The effect of storage on the biomechanical behavior of articular cartilage--a large strain study. The transplantation of stored shell osteochondral allografts is a potentially useful alternative to total joint replacements for the treatment of joint ailments. The maintenance of normal cartilage properties of the osteochondral allografts during storage is important for the allograft to function properly and survive in the host joint. Since articular cartilage is normally under large physiological stresses, this study was conducted to investigate the biomechanical behavior under large strain conditions of cartilage tissue stored for various time periods (i.e., 3, 7, 28, and 60 days) in tissue culture media. A biphasic large strain theory developed for soft hydrated connective tissues was used to describe and determine the biomechanical properties of the stored cartilage. It was found that articular cartilage stored for up to 60 days maintained the ability to sustain large compressive strains of up to 40 percent or more, like normal articular cartilage. Moreover, the equilibrium stress-strain behavior and compressive modulus of the stored articular cartilage were unchanged after up to 60 days of storage.


A noninvasive method of measuring Max(dP/dt) of the left ventricle by Doppler echocardiography. Although slightly affected by alterations in preload, the maximum first derivative of left ventricular pressure with respect to time, Max(dP/dt), is widely regarded as a simple and convenient index of cardiac contractility for clinical use. The feasibility of noninvasive, hence repeatable, measurement of Max(dP/dt) will certainly lead to re-evaluation of its usefulness. Max(dP/dt) is given by the following equation: Max(dP/dt) = rho c Max(du/dt), where rho is the blood density, c the pulse wave velocity, and mu the flow velocity in the aorta. This equation has been previously validated in animal experiments and has now been applied to the clinical setting for the first time. In 20 patients without aortic stenosis, left ventricular pressure was measured with a catheter-tip micromanometer, aortic ejection flow velocity was measured by Doppler echocardiography, and pulse wave velocity by mechanocardiography or Doppler echocardiography. Then, delta c Max (du/dt was calculated from the measured data and compared with measured Max (dP/dt). A significant positive correlation was found between them (rho c Max (du/dt) = 0.96 x Max (dP/dt) + 6.52, r = 0.83, p < 0.001). In 11 patients with hypertension, rho c Max (du/dt) was obtained before and after long-term (average 13.1 months) treatment with antihypertensive drugs. In spite of the expected reduction in blood pressure and the regression of left ventricular mass, rho c Max (du/dt) remaioned unchanged. In 9 patients with dilated cardiomyopathy, the effects of beta 1-agonist were tested at the beginning of therapy (30 mg/day denopamine) and 6 months later. The increase in rho c Max (du/dt) observed 1 hour after oral administration of he drug had not changed significantly 6 months later. We conclude that the index rho c Max (du/dt), is useful in assessing the contractile state of the left ventricle noninvasively.


A general method of determining the frequency-dependent propagation coefficient and characteristic impedance of an artery in the presence of reflections. An iterative method of calculating propagation parameters at harmonics of heart rate for a uniform vascular segment from a combination of four arterial waveform measurements is presented. Measurements of blood pressure, vascular diameter, and blood flow-rate may be combined arbitrarily provided only that at least one measurement of pressure and one of flow-rate be included; the requirement of four measurements implies at least two measurement sites along the vessel. The analysis is thus a generalization of those associated with previous methods of determining propagation parameters, allowing for instance relaxation of the requirement of equal spacing in the three-point method. Results are presented for the propagation of an impulse along a rubber tube when the measurements are pressure at two sites, flow-rate and diameter.


Does vibration cause poststenotic dilatation in vivo and influence atherogenesis in cholesterol-fed rabbits? Arterial post-stenotic dilatation (PSD) is a fusiform swelling immediately down-stream to a stenosis. It is characterized by the presence of turbulent blood flow and wall vibration which has been claimed by others to be causal by producing structural weakening. We tested the hypothesis that vibration causes PSD in vivo by attaching electromagnetic and pneumatic vibrators to the aortic wall in chronic rabbits. We also observed whether mechanical vibration of the aorta in vivo influenced the distribution of oil-red-O lesions during one percent dietary cholesterol feeding. Low mass vibration gauges were developed to measure the vibration. Electromechanical vibrators having a ceramic magnet slug within a coil supplied with 50 Hz were glued to the aorta of chronic rabbits and the vibration maintained for an average of 8 weeks. Despite greater amounts of energy imparted to the wall there was no dilatation or difference in oil-red-O staining from the controls. Five weeks vibration at 100 Hz and an amplitude equal to the normal diameter pulse also produced no dilatation. We conclude that vibration does not cause PSD in vivo and suggest that its cause is likely to involve the vascular muscle stimulated by the effect of turbulent flow on the endothelium.


Numerical analysis of flow in an elastic artery model. Oscillatory and pulsatile flows of Newtonian fluids in straight elastic tubes are simulated numerically with the aid of Ling and Atabek's "local flow" assumption for the nonlinear convective acceleration terms. For the first time, a theoretical assessment of the local flow assumption is presented, and the range of validity of the assumption is estimated by comparison with perturbation solutions of the complete flow problem. Subsequent simulations with the local flow model indicate that the flow field and associated wall shear stress are extremely sensitive to the phase angle between oscillatory pressure and flow waves (impedance phase angle). This phase angle, which is a measure of the wave reflection present in the system, is known to be altered by arterial disease (e.g., hypertension) and vasoactive drugs. Thus, the paper elucidates a mechanism by which subtle changes in systemic hemodynamics (i.e., phase angles) can markedly influence local wall shear stress values.


Advanced spectral estimators for detailed blood flow studies. Recent publications have emphasized the relationship between the spectrum of the backscattered acoustic signal, beam geometry, and flow patterns in the measurement of blood flow by Doppler ultrasound. On this basis, we believe that in the future more importance will be placed on analyzing various characteristics of the spectral shape rather than absolute parameters of measurement, such as the mean frequency. The potential of this approach for extracting more information from the raw Doppler signal is introduced by considering the Spectral Broadening Index (SBI). We explain the use of the SBI parameter for measuring flow angle under restricted flow conditions. This is done by using an analytic/computational model for prediction of the spectral broadening effect. By simulation study, the performance of various spectral estimators for determining the SBI from finite Doppler signal segments is evaluated.


Numerical simulation of steady flow in a model of the aortic bifurcation. The governing equations of steady flow of an incompressible viscous fluid through a 3-D model of the aortic bifurcation are solved with the finite element method. The effect of Reynolds number on the flow was studied for a range including the physiological values (200 < or = Re < or = 1600). The symmetrical bifurcation, with a branch angle of 70 degrees and an area ratio of 0.8, includes a tapered transition zone. Secondary flows induced by the tube curvature are observed in the daughter tubes. Transverse currents in the transition zone are generated by the combined effect of diverging and converging walls. Flow separation depends on both the Reynolds number and the inlet wall shear.


Pulsatile flow in a constricted channel. A nonuniform channel is used as a simple model of a constricted arterial vessel. Flow patterns have been calculated for pulsatile flow with both sinusoidal and nonsinusoidal flow rates for a range of Reynolds number, Re, and Strouhal number, St. The results show that even for relatively low frequency flows a strong vortex wave will be generated with a complex wall shear stress distribution and peak values much greater than those found in steady or unsteady parallel flow. The vortex wave increases in strength with increasing Re and St, with its total length and wavelength independent of Re but inversely proportional to St. The form of the imposed flow rate is found to have an important effect on the flow and the shear stress distribution.


Chaotic oscillations in a simple collapsible-tube model. A steady flow through a segment of externally pressurized, collapsible tube can become unstable to a wide variety of self-excited oscillations of the internal flow and tube walls. A simple, one-dimensional model of the conventional laboratory apparatus, which has been shown previously to predict steady flows and multiple modes of oscillation, is investigated numerically here. Large amplitude oscillations are shown to have a relaxation structure, and the nonlinear interaction between different modes is shown to give rise to quasiperiodic and apparently aperiodic behavior. These predictions are shown to compare favorably with experimental observations.


Longitudinal tension variation in collapsible channels: a new mechanism for the breakdown of steady flow. There are several mechanisms potentially involved in the breakdown of steady fluid flow in a collapsible tube under external pressure. Here we investigate one that has received little attention in the past: the fact that the longitudinal tension in the tube wall, T, decreases with distance downstream as a consequence of the viscous shear stress exerted by the fluid. If the tube is long enough, or the initial tension small enough, T may fall to zero before the end of the collapsible tube, and unsteady motion would presumably then ensue; this is what we mean by "breakdown." We study the phenomenon theoretically, when the flow Reynolds number is of order one, using lubrication theory in a symmetric two-dimensional channel in which the collapsible tube is replaced by membranes occupying a segment of each wall. The resulting nonlinear ordinary differential equations are solved numerically for values of the dimensionless parameters that cover all the qualitatively different types of solution (e.g., in which the channel is distended over all its length, collapsed over all its length, or distended in the upstream part and collapsed downstream). Reducing the longitudinal tension has a marked effect on the shape of the collapsible segment, causing it to become much more deformed for the same flow rate and external pressure. Indeed, the wall slope is predicted to become very large when the downstream tension is very small, so the model is not self-consistent then. Nevertheless, the parameter values for which T becomes zero are mapped out and are expected to be qualitatively useful.(ABSTRACT TRUNCATED AT 250 WORDS)


Possible sources of discrepancy between sphygmomanometer cuff pressure and blood pressure quantified in a collapsible-tube analogue. This paper examines the assumption that the audible events detected as Korotkov sounds in sphygmomanometry occur when blood pressure equals arm-cuff pressure. Several effects that contribute to discrepancy between these pressures are quantified using an idealised arm-and-cuff system consisting of a thick-walled collapsible tube subject to external compression along a central part of its length. The effects studied are (1) transverse pressure difference, resulting from tissues sustaining a part of the external compression through (a) circumferential bending stiffness and (b) longitudinal curvature of the tensed localised neck at the site of initial collapse, (2) longitudinal pressure difference between upstream pressure and pressure at the collapse point due to both (a) viscous and (b) inertial pressure drop. These effects are found to compensate partially for each other; the pressure within the vessel at the collapse point is less than the cuff pressure, but is also less than the blood pressure at the upstream end of the cuff. All four of the contributing terms increase proportionally to the flow-rate raised to a power greater than one, except the viscous pressure drop. Owing to a progressive shortening of the collapsed neck as flow-rate increases, the viscous term is almost independent of the flow-rate. The overall discrepancy displays less flow-rate dependency and is smaller than some of the terms which contribute to it. This means that considerable accuracy is needed if measurements of the effects are to be used to correct the raw data on cuff pressure at the time of Korotkov sound emission so as to obtain an improved estimate of the blood pressure.


Blood flow in a brachial artery compressed externally by a pneumatic cuff. Blood flow in human brachial arteries, compressed by a pneumatic cuff for blood pressure measurement, is examined using several different noninvasive techniques. From the experimental results it is shown that, when arterial pressure distal to the cuff is always lower than cuff pressure, flow in the artery under the cuff becomes supercritical near the cuff downstream margin and no reflection occurs there and the reflected wave from the peripheral vascular system of the arm does not propagate beyond the cuff downstream margin. Therefore an unsteady transition from supercritical to subcritical flow occurs near the cuff downstream margin. When the peak value of distal arterial pressure exceeds cuff pressure, a reflection occurs near the cuff downstream margin. The reflection becomes stronger corresponding to decrement of the cuff pressure and the whole artery segment under the cuff inflates fully at systole. At diastole, however, the artery segment under the cuff does not collapse completely and, hence, the phenomenon becomes that of pressure wave propagation in a partially collapsed artery segment.


Steady flow through collapsible tubes: measurements of flow and geometry. Compliant tubes attain a complex three-dimensional geometry when the external pressure exceeds the internal pressure and the tube is partially collapsed. A new technique for remote measurement of dynamic surfaces was applied to classical experiments with collapsible tubes. This work presents measurements of the three-dimensional structure of the tube as well as pressure and flow measurements during static loading and during steady-state fluid flow. Results are shown for two tubes of the same material and internal diameter but with different wall thicknesses. The measured tube laws compare well with previously published data and suggest the possible existence of a similarity tube law. The steady flow measurements did not compare well with the one-dimensional theoretical predictions.


6R instrumented spatial linkages for anatomical joint motion measurement--Part 1: Design. Six-revolute-joint instrumented spatial linkages (6R ISLs) have become often-used devices to measure the complete six-degree-of-freedom motion of anatomical joints. Accuracy of motion measurement depends on ISL design and calibration technique. In this paper, a design process is outlined that uses computer graphics and numerical methods as aids in developing 6R ISLs that (i) physically assemble within the desired range of motion of the joint; (ii) do not collide with either the experimental apparatus or the subject joint; (iii) avoid singular linkage configurations that can cause forces to be applied to the joint; and (iv) measure selected anatomical motions most accurately. It is found that a certain subgroup of 6R linkages are suitable for accurate measurement of specific motions, and can be the basis for new ISL designs. General guidelines are developed that can assist in the generation of unique linkage designs for different anatomical joints. The design process is demonstrated in the creation of an ISL to measure knee motion.


Evaluation of precision grip using pneumatically controlled loads. Precise control of grip force and finger movement is a fundamental aspect of motor tasks in which an object is held and manipulated between the subject's fingers. A new device to measure motor performance which simultaneously records grip force and finger movement is described. The subject holds a small, compressible cylinder between thumb and index finger. The load opposing finger movements is controlled pneumatically and may be altered with computer software. Different types of loads (e.g., constant load, spring load) may be applied. In addition, reactions to perturbing stimuli (e.g., fast changes of load) may be measured. Construction principles and examples of tasks investigating different aspects of hand function are presented in the paper.


Effects of aging on the content, composition and synthesis of sphingomyelin in the central nervous system. Sphingomyelin (SPH) content and composition in different regions of the brain were analyzed in 2.5, 21.5 and 26.5-month-old rats. SPH content increased in the cerebral hemispheres, cerebellum and medulla oblongata plus pons as age increased. The highest SPH content was observed in 26.5-month-old rats, with values increasing by 1.74, 2.75 and 0.88-fold, respectively, over 2.5-month-old rats. The SPH fatty acid composition of brains from aged rats was markedly different from that of adult rats. Between 2.5 and 26.5 months of age the monoenoic/saturated fatty acid ratio increased from 0.22, 0.30 and 0.54 to 0.54, 0.68 and 1.03 in cerebral hemispheres, cerebellum and medulla oblongata plus pons, respectively. The percentage and content of fatty acids longer than 22 carbon atoms esterified to SPH increased with age from 18, 26 and 44 to 48, 52 and 62 mole % in cerebral hemispheres, cerebellum and medulla oblongata plus pons in 26.5-month-old rats. In subcortical white matter from aged rats, monoenoic 22-26 carbon atom fatty acids increased more than the saturated ones in 21.5-month-old rats relative to 2.5-month-old rats. In vitro synthesis of SPH from [3H]choline and [3H]palmitic acid in cerebral cortex and cerebellum showed no significant differences between adult rats and those 21.5 months of age. In cerebellum and in cerebral cortex, [14C]serine incorporation increased in aged rats. The results suggest that aging induces increases in both SPH content and in the monoenoic/saturated fatty acid ratio. These increases are quantitatively different in all brain regions analyzed.


Chronic drug infusion into the scala tympani of the guinea pig cochlea. This research describes a unique, effective and inexpensive delivery system to provide discrete quantities of drugs on a chronic basis to the inner ear. The amount of the drug administered and specific timing of each administration are under investigator control. A micro-injection system mounted atop an animal's head is shown to permit repeated application of agents which effectively block neural responsiveness (tetrodotoxin) on a daily basis for periods up to 2 weeks. Cannulation of the inner ear and chronic delivery of control substances (artificial perilymph) do not affect function. This system may be used to administer drugs to other compartments of the body (e.g., the brain) on a chronic basis for neurophysiologic and neuropharmacologic investigations.


Determination of beta-carotene in plasma, blood cells and buccal mucosa by electrochemical detection. The beta-carotene concentrations in plasma, blood cells and buccal mucosal cells were determined by high-performance liquid chromatography with electrochemical detection. This method was 1,000 times more sensitive than the conventional spectrophotometric method. Polymorphonuclear cells and red blood cells had lower beta-carotene levels than the other cells. After oral administration of 580 mg/day of all-trans beta-carotene to human male volunteers for a week, the beta-carotene concentrations in all cell types increased at least several times above the original levels.


Gender and dietary fat affect alpha-tocopherol status in F344/N rats. For four weeks, groups of eight male and eight female F344/N rats were fed diets containing 15.5, 20, 30 or 40% of energy (en%) as fat. The fat was composed of corn oil and beef tallow with 9 en% from linoleate in all diets. Females had greater mean hepatic alpha-tocopherol levels, whereas males had greater plasma alpha-tocopherol and cholesterol concentrations. In males, the plasma ratio of alpha-tocopherol/cholesterol was significantly greater than in females (P < 0.05). Plasma alpha-tocopherol increased with increasing en% fat (r = 0.51, P < 0.001) in both sexes, but dietary fat did not alter hepatic alpha-tocopherol levels. These results suggest that plasma alpha-tocopherol may serve as a biomarker of total dietary fat intake and that in F344/N rats gender differences affect alpha-tocopherol and cholesterol status.


The RIPP density estimate: an alternative method for the estimation of peri-stimulus spike density. Cross-correlation between stimuli and neuronal discharges determines the peri-stimulus spike density. This density function is usually estimated by the peri-stimulus time histogram (PSTH). In this paper an alternative method for spike-density estimation is considered that employs estimation of the rate of an inhomogeneous Poisson process by Jth waiting times. This procedure is called the RIPP density estimate. It involves sorting the spike times for all trials and obtaining the Poisson rates for successive groups of spikes. By application of this procedure to simulated action-potential sequences from the leaky-integrator model subject to a realistic input, it is shown that the RIPP density estimate reveals much more information from a given set of spike train data than a PSTH. An application of the RIPP density estimate to experimental spike train data from a human hand muscle motoneuron subject to a low-threshold-afferent volley is also presented.


NEUROLAB, a comprehensive program for the analysis of neurophysiological and behavioural data. A comprehensive and versatile computer software for IBM-compatible microcomputers has been developed. It is designed for quantitative off-line analysis of A/D-sampled intracellular or extracellular recordings and behavioural or stimulus data. The program works with single files or file sets. It supports data to be viewed on the monitor and allows sectioning of interesting data for common analysis. It offers 19 filters/operators for data processing and comprehensive possibilities to set and calculate trigger points. Data of trigger points can be exported as ASCII files. Standard neurophysiological histograms like interval-, PST-, phase histograms or auto- and cross-correlograms can be obtained. Time-dependent and phase-dependent averaging is possible for all original and filtered data. All graphical output on the display can directly be copied to a plotter/laser printer or HP-GL file by keyboard commands.


Human milk in disease: lipid composition. Differences in the lipid composition of human milk have been described in maternal diseases known to affect fat metabolism. Diseases such as diabetes, cystic fibrosis, hypobetalipoproteinemia and Type I hyperlipoproteinemia affect the quantity and quality of human milk fat. Increased fatty acid chain elongation and changes in desaturation (especially delta 6 desaturase), as well as changes in lipid class composition, have been shown in diabetes and cystic fibrosis, whereas compensatory increases in medium-chain fatty acids have been described in hypobetalipoproteinemia and Type I hyperlipoproteinemia. It is important to realize that these observations were made either on single women or on very small groups of women. In infant diseases, such as breast milk jaundice and ectopic eczema, changes in polyunsaturated fatty acids in maternal milk have been described.


The absorption of fish oils and concentrates. Both preventive and curative therapies have created a considerable demand for eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. The most common sources for omega 3 fatty acids are fish oil. The concentrations of EPA and DHA in commercial oils, after modest enrichment, reach about 300 mg/g; alternative technologies can produce reasonably priced fish oils containing 400 or even 500 mg/g of omega 3 acids. When the acids are liberated from the glycerides, concentrates of ethyl esters or free acids with 65 to 70% total omega 3 fatty acids (at least 50% EPA + DHA) are readily prepared. Difficulties have arisen because most clinical trials have used fish oils of unspecified composition, and some trials are now based on either ethyl esters or free acids. There are at least three different, but not mutually exclusive, absorption routes in humans, namely the preduodenal route, the lymphatic route via chylomicrons, and the route via the portal vein to the liver. This makes it difficult to compare results. The difficulty in obtaining dose-related clinical data may in part be due to the form in which the omega 3 acids are offered and due in part to the natural presence of these fatty acids in the body. The nontriglyceride forms, especially the free acids, have been advocated for standardization of trials to facilitate interlaboratory comparisons.


Comparison of methods for the in vitro assembly of postmortem human brain microtubules that retain the microtubule-associated protein tau. Several methods for the in vitro assembly of microtubules from postmortem human brain were compared for the purpose of obtaining microtubule preparations that best retained their microtubule-associated proteins. The polymerized microtubules from the preparations were examined by negative staining and electron microscopy and shown to consist of well-formed microtubules with varying amounts of abnormal assembly products that differed between methods. The microtubule protein was analyzed by SDS-polyacrylamide gel electrophoresis, quantitative densitometry, as well as trans-blotted onto membranes which were reacted with monoclonal antibodies to tubulin subunits and microtubule-associated proteins. All the preparations were found to contain both the alpha- and beta-tubulin subunits with quantitative differences, but they varied most, both quantitatively and qualitatively, in their content of microtubule-associated proteins. The optimal method for the assembly of soluble tubulin from postmortem human brain cytosol into intact microtubules which specifically retained most of their MAPs, especially tau, employed 4 M glycerol assembly buffer in the presence of 10 microM taxol and 1 mM GTP. The isolation methods were used to compare young and aged brains, and there were fewer microtubule-associated proteins, especially tau, associated with the microtubules in advanced age, in all preparations.


Effect of fish oil on the fatty acid composition of human milk and maternal and infant erythrocytes. To examine the effect of fish oil supplementation on the fatty acid (FA) composition of human milk and maternal and infant erythrocytes, five lactating women were supplemented with 6 g of fish oil daily for 21 d. Usual maternal diets contained 1,147 mg of total n-3 FA, with 120 mg from very long-chain (> C18) n-3 FA. Supplementation increased dietary levels to 3,092 mg of total n-3 FA and 2,006 mg of very long-chain n-3 FA. Milk samples were collected daily, prior to fish oil ingestion, and at 4-h intervals on days 1, 7, 14 and 21. Milk n-3 FA content increased within 8 h and reached steady state levels within one week. The n-6 fatty acid content decreased. Erythrocyte eicosapentaenoic acid content increased from 0.24% to 1.4% (P < 0.01) in mothers and from 0.11% to 0.70% (P < 0.05) in infants. Docosapentaenoic acid increased from 1.4% to 2.2% (P < 0.05) in mothers and from 0.30% to 0.78% (P < 0.01) in infants. There was no significant change in docosahexaenoic acid or n-6 fatty acid content. Maternal platelet aggregation responses were variable. No differences in milk or plasma tocopherol levels were noted.


Positional specificity of gastric hydrolysis of long-chain n-3 polyunsaturated fatty acids of seal milk triglycerides. Long-chain n-3 polyunsaturated fatty acids (n-3 PUFA) of marine oils are important dietary components for both infants and adults, and are incorporated into milks following maternal dietary intake. However, little is known about the hydrolysis of these PUFA from milk triglycerides (TG) by lipases in suckling young. Seals, like humans, possess gastric lipase; however, the milk lipids of seals and sea lions are almost devoid of the readily hydrolyzable medium-chain fatty acids, and are characterized by a large percentage (10-30%) of n-3 PUFA. Gastric hydrolysis of milk lipids was studied in vivo in suckling pups of three species (the California sea lion, the harp seal and the hooded seal) in order to elucidate the actions and specificity of gastric lipases on milk TG in relation to fatty acid composition and TG structure. Regardless of milk fat content (31-61% fat) or extent of gastric hydrolysis (10-56%), the same fatty acids were preferentially released in all three species, as determined by their relative enrichment in the free fatty acid (FFA) fraction. In addition to 16:1 and 18:0, these were the PUFA of 18 carbons and longer, except for 22:6n-3. Levels of 20:5n-3 were most notably enriched in FFA, at up to five times that found in the TG. Although 22:6n-3 was apparently also released from the TG (reduced in the diglyceride), it was also notably reduced in FFA.(ABSTRACT TRUNCATED AT 250 WORDS)


n-3 fatty acid requirements of the newborn. Whether docosahexaenoic acid (22:6n-3) is an essential nutrient for term or preterm infants, or if not, the quantity of dietary linolenic acid (18:3n-3) needed to support sufficient synthesis of 22:6n-3 for assimilation in the central nervous system is unknown. Infants fed formulas have lower plasma and red blood cell (RBC) levels of 22:6n-3 than breast fed infants. No relationship between the intake of 18:3n-3 in formula (0.8 or 4.5% of fatty acids, 18:2n-6/18:3n-3 ratio 35:1 or 7:1, respectively) and the infant's RBC 22:6n-3 was found. Premature infants (< 33 wk gestation) also showed a decrease in RBC 22:6n-3 during feeding with formula containing 18:3n-3 as the only n-3 fatty acid. However, a marked decrease in plasma and RBC 22:6n-3 occurred between premature birth and the start of full enteral feeding at 1-2 wk of age. This was not reversed by breast milk or formula feeding. Piglets, which are appropriate for studies of infant lipid metabolism, had decreased brain synaptic plasma membrane, retina and liver 22:6n-3 and increased 22:5n-6 when fed formula with 0.8% fatty acids (0.3% of kcal) as 18:3n-3. Formula with 4.0% fatty acids (1.7% of kcal) as 18:3n-3 resulted in similar accretion of 22:6n-3 in the organs compared to milk fed animals. The studies suggest the dietary requirement for 18:3n-3 in term animals in energy balance exceeds 0.3% diet kcal.(ABSTRACT TRUNCATED AT 250 WORDS)


Addition of long-chain polyunsaturated fatty acids to formula for very low birth weight infants. Thirty-four premature infants who were appropriate for gestational age and weighing less than 1500 g at birth were fed "preemie" SMA-24 formula, "preemie" SMA-24 formula manufactured to contain C20 and C22 omega 6 and omega 3 fatty acids (LCPE-SMA), or expressed milk (EBM). Blood samples were drawn from a small arm vein during the first week of life and after 28 days of feeding. The fatty acid content of plasma phospholipids was determined. Infants fed SMA-24 had a high content of 18:2 omega 6 in plasma phospholipids. Feeding LCPE-SMA normalized plasma phospholipid levels of C20 and C22 omega 6 and omega 3 fatty acids to be similar to levels of C20 and C22 omega 6 and omega 3 fatty acids found in infants fed EBM, and significantly higher than characteristic levels for infants fed SMA-24. Feeding LCPE-SMA or EBM results in a balanced incorporation of C20 and C22 omega 6 and omega 3 fatty acids into phospholipids derived from the liver or perhaps the small intestine.


First year growth of preterm infants fed standard compared to marine oil n-3 supplemented formula. Very low birth weight (VLBW) infants (748-1390 g, n = 65) were randomly assigned to receive control or marine oil-supplemented formula when they achieved intakes > 454 kJ (110 kcal)/kg/d of a formula designed for VLBW infants. Study formulas with or without marine oil were provided until 79 wk of postconceptional age (PCA), first in a formula designed for preterm infants followed by a formula designed for term infants. Infants were studied at regular intervals through 92 wk PCA. Weight, length, and head circumference were determined by standardized procedures and normalized to the National Center for Health Statistics figures for growth of infants born at term of the same age and gender. Mean normalized weight, weight-to-length, and head circumference were greatest at 48 wk and decreased thereafter. The decline in normalized weight was greater in infants fed the marine oil-supplemented formula. Beginning at 40 wk, marine oil-supplemented infants compared to controls had significantly poorer Z-scores for weight, length and head circumference. In addition, birth order (negatively) and maternal height (positively) influenced weight and length achievement in infancy as shown previously in infants born at term.


Human mammary gland function at the onset of lactation: medium-chain fatty acid synthesis. The onset of medium-chain fatty acid synthesis in the human mammary gland was investigated. Colostrum and serum were collected from 31 healthy women and the fatty acid composition of total lipid was analyzed by gas-liquid chromatography. Although colostrum/serum ratios for most fatty acids range from 0.7-2.4, very low levels of 10:0 and 12:0 were present in serum lipids as compared to much higher concentrations of these fatty acids in colostrum lipids (colostrum/serum ratio 16.23 and 17.11 for 10:0 and 12:0, respectively). We have previously found that medium-chain fatty acid levels are very low in prepartum mammary secretions (6-10 wk before term delivery) but are higher and similar in colostrum of women who deliver preterm (3-14 wk) or at full term. The data indicate that parturition, irrespective of length of pregnancy, is the trigger for medium-chain fatty acid synthesis in the human mammary gland.


Lactation curves and effect of pup removal on milk fat of C57Bl/6J mice fed different diet fats. Groups of C57Bl/6J mice, fed either a cis (C-Diet) or trans diet (T-Diet) were milked without preconditioning at 6, 8, 10 and 12 days postpartum. On day 10, groups of mice were also milked 4, 6 and 18 h after separation of the pups. Except for the 18-h separation, all T-Diet fed animals produced milk of lower fat content than did the C-Diet animals (P < 0.001) throughout the lactation period measured. In the C-Diet mice, the 6-h separation period resulted in a decrease (P < or = 0.03) in fat, but the diet-depressed milk fat of T-Diet animals was not decreased further until the 18-h separation period. Milk volume increased as lactation progressed and was greatly increased as a result of preconditioning (P < or = 0.001), even at 4 h of separation when fat was not reduced, and was always greater for T-Diet animals. Within diet groups, fatty acid composition was similar throughout the lactation period studied and was not affected by preconditioning except in the 18-h separation period, when de novo fatty acids were significantly reduced (P < or = 0.05). The data are consistent with the hypothesis that preconditioning results in lowered milk fat values and that preconditioning techniques can explain discrepancies in literature values for murine milk fat.


Bile salt stimulated lipase: comparative studies in ferret milk and lactating mammary gland. Bile salt stimulated lipase (BSSL) activity is 10-20 times higher in ferret milk than in human milk. We have used the ferret to study BSSL activity in lactating mammary gland and in mammary cells isolated by hyaluronidase-collagenase treatment followed by Ficoll gradient centrifugation. Furthermore, we have compared the characteristics of BSSL in the tissue preparations (homogenate or cells) to BSSL of ferret milk and to BSSL purified from ferret and human milk. The characteristics of BSSL in ferret mammary gland preparations and milk were similar to those of human milk BSSL--absolute requirement of primary bile salts, pH optimum of 7.5-9.0, stability at pH 3-9 and inhibition by eserine (physostigmine) and by serum. Purified ferret milk BSSL had a lower molecular weight (90kD) than did human milk BSSL (125 kD). There was an 86% homology of the N-terminal amino acid sequence between BSSL of ferret and of human milk. The marked similarity in characteristics between BSSL in ferret and human milk and the high activity of BSSL in ferret milk (520 U/mL colostrum and 250 U/mL mature milk) indicate that this species is an ideal animal model for the study of the synthesis and secretion of this digestive lipase which constitutes a significant portion (1-2%) of total milk protein.


Neutral glycolipids of human and bovine milk. The neutral glycolipids of milk, a small fraction of the total lipids, are of potential biological importance. The simultaneous quantitation of the simple (less than five sugars) glycosphingolipids of human milk samples was achieved by high-pressure liquid chromatography. The samples, representing various stages of lactation, parity of the nursing child, and age of the mother, contained similar glycolipid patterns, but with varying individual glycolipid concentrations. The cerebrosides are major glycosphingolipids of human milk: the non-hydroxylated fatty acid (NFA)-containing species are present at 1.8 microM, and the hydroxylated and/or short-chain fatty acid-containing species (HFA) are present at 1.7 microM; NFA lactosylceramide is present at 931 nM. The cerebrosides appear to be primarily galactosylceramides (galactocerebrosides); glucosylceramides (glucocerebrosides) are a minor component. Globotriaosylceramide (Gb3) is found at 50 nM and 73 nM for the NFA and HFA species, respectively, while globoside (Gb4) is found at 45 nM and 46 nM for the NFA and HFA species. Bovine milk glycosphingolipids differ from those of human milk, with bovine milk containing mainly NFA glucosylceramide (8 microM) and NFA lactosylceramide (17 microM); bovine milk contains little Gb3 or Gb4.


Oxidative interactions of cholesterol in the milk fat globule membrane. The effects of oxidative interactions between cholesterol and milk fat globule membrane (MFGM) components, i.e., nonlipid fraction, total lipid, nonpolar lipid and polar lipid, on cholesterol oxidation were studied in the presence and absence of water. In the dry state, cholesterol natively present in MFGM appeared to be protected at 135 degrees C. The nonpolar lipid and nonlipid fraction contributed to the protective effect of MFGM. Added cholesterol accelerated the oxidation of membrane lipid fractions. At 75 degrees C, pure cholesterol and membrane lipid fractions did not show significant interaction. However, cholesterol and other lipids in MFGM were less stable than when these were heated separately. When cholesterol and membrane lipids were mixed in an aqueous medium at 75 degrees C, each accelerated the oxidation of the other. The MFGM exhibited a high protective effect on cholesterol oxidation in an aqueous environment. The nonlipid fraction protected cholesterol against oxidation, whereas the lipid fraction was destructive. In the absence of water, the net balance between these two opposing factors was destructive. The presence of water reversed the balance in favor of protection.


Fatty acid composition of black bear (Ursus americanus) milk during and after the period of winter dormancy. Black bears give birth and lactate during the 2-3-mon fast of winter dormancy. Thereafter the female emerges from the den with her cubs and begins to feed. We investigated fatty acid patterns of milk from native Pennsylvania black bears during the period of winter dormancy, as well as after den emergence. Throughout winter dormancy, milk fatty acid composition remained relatively constant. The principal fatty acids at all times were 14:0, 16:0, 16:1, 18:0, 18:1, 18:2n-6, 18:3n-3 and 20:4n-6. After den emergence, large changes occurred in almost all the fatty acids, particularly in 18:2n-6 and 18:3n-3. Large variability among the active free-ranging animals likely reflected differences in diet. In a carnivore, with apparently limited de novo synthesis of fatty acids, milk fatty acid composition may be affected by factors such as transition from reliance on stored lipids to feeding, and by temporal changes in dietary intake.


High-performance liquid chromatography of human milk triacylglycerols and gas chromatography of component fatty acids. Human milk triacylglycerols were separated by high-performance liquid chromatography. A 5-mu Supelcosil LC-18 column (Supelco, Inc., Bellefonte, PA) was used with acetone/acetonitrile (64:36, vol/vol) as mobile phase. Triacylglycerols were tentatively identified based on theoretical carbon number and relative retention time. Despite changes resulting from dietary fat variation, the major component triacylglycerols were those composed of palmitic, oleic and linoleic acids. Triacylglycerols with palmitic, stearic and oleic acids were present as minor components. Fatty acids were quantified by gas chromatography relative to an internal standard. Ratios of n-6/n-3 fatty acids were found to be higher than previously reported.


Co-existence of colonies with different serotypes and other biological characteristics in clinical isolates of Pseudomonas aeruginosa. The biological characteristics of individual colonies of Pseudomonas aeruginosa from 138 specimens were investigated. Of these isolates, 90 (65.2%) formed colonies of similar appearance and morphology, and 48 (34.8%) formed colonies which differed either in appearance or morphology. The individual colonies of 138 isolates were tested for serotype. The former 90 isolates formed only the colonies with one kind of serotype, whereas 17 of the latter 48 isolates formed the colonies with more than one kind of serotype. All the 9 isolates tested also differed in other biochemical characteristics: acid productions from xylose, mannitol and maltose, urease production and gelatin liquefaction. beta-Lactamase activity was investigated in 7 isolates forming colonies with more than one serotype. There were no marked differences in beta-lactamase activity among the different colonies in 5 isolates but marked differences among those in the other 2 isolates.


Characterization of an amorphous and soluble hemagglutinin from Yersinia pseudotuberculosis. Yersinia pseudotuberculosis which were screened out depending on auto-agglutination and Ca2+ dependency, were examined for their production of hemagglutinin (HA), and its purification and characterization were performed. The HA with a broad reactivity with various mammalian erythrocytes was recovered from the culture supernatant of these strains grown at 37 C but not 25 C. HAs from two strains, R148R and T1040, were purified by salt precipitation, gel filtration and anion-exchange chromatography by HPLC. Both purified HAs were cysteine-deficient acidic protein with an apparent molecular weight in the range of 15,000 to 16,000. N-terminal amino acid sequences of the first 25 residues were found to share 12% identity with that of afimbrial adhesin from enterotoxigenic Escherichia coli 2230. Immunoelectron microscopy and immunodiffusion test with polyclonal antiserum raised against the purified R148RHA demonstrated that the HA was associated with the amorphous aggregates which were detached from bacteria. These results suggest that the HA of Y. pseudotuberculosis belongs to a third type of HA produced by the yersinial species.


Sensitivity of polymerase chain reaction assay for Rickettsia tsutsugamushi in patients' blood samples. We developed a nested polymerase chain reaction (PCR) method to detect Rickettsia tsutsugamushi (R. tsutsugamushi) DNA and determined its sensitivity. Primers were selected from the DNA sequence of the 58-kDa group-specific antigen gene of the Karp strain. The target sequence of rickettsial DNA was detectable as the band corresponding to 88 bp in 1.0 microgram of the DNA extracted from BS-C-1 cells infected with R. tsutsugamushi. Rickettsia-specific bands were observed not only for the homologous Karp strain, but also for four heterologous strains: two other reference strains (Gilliam and Kato) and two prototype strains prevalent in Miyazaki district (Irie and Hirano). The minimum copy number detectable by this method was estimated to be five rickettsiae. All of nine peripheral blood mononuclear cell samples from patients with tsutsugamushi disease who were seen 2-11 days after disease onset tested positive for rickettsial DNA. The PCR assay method presented here could be a specific diagnostic tool for tsutsugamushi disease, especially in its early acute stage.


Species dependency of in vitro macrophage activation by bacterial peptidoglycans. The effect of various bacterial cell wall components on in vitro biological function of murine peritoneal exudate macrophages was evaluated. We examined four different parameters of metabolic activity and monokine secretion. Peritoneal exudate macrophages from rats and guinea pigs, all of the strains tested, were stimulated by whole bacterial cell wall preparations, purified bacterial cell wall peptidoglucans, its water-soluble peptidolglycan fragments, muramyl dipeptides and amphipathic substances. Murine peritoneal exudate macrophages were activated by amphipathic substances of gram-positive bacteria. However, macrophages from mice, irrespective of strains, were not stimulated in the in vitro assay systems by purified bacterial cell wall peptidoglycan, water-soluble bacterial peptidoglycan fragments or muramyl dipeptides. These results suggest that macrophage activation by bacterial peptidoglycan in vitro is animal species specific.


Killing of Escherichia coli by mononuclear phagocytes and neutrophils stimulated in vitro with beta-1,3-D-polyglucose derivatives. Human monocytes, human peritoneal macrophages, mouse peritoneal macrophages and human peripheral neutrophils pretreated with beta-1,3-D-polyglucose derivatives showed pronounced bactericidal capacity to Escherichia coli compared to control cells. The increased bactericidal capacity was detectable in mononuclear phagocytes over a wide range of concentrations of bacteria. Granulocytes, however, showed bactericidal capacity only at low concentrations of bacteria. The pretreated mononuclear phagocytes released significant amounts of IL-1 and PGE2. However, there was no significant release of tumor necrosis factor (TNF). By incubating unstimulated cells with purified IL-1 and TNF, the bactericidal activity of neutrophils and mononuclear phagocytes was enhanced. Our data indicate that the inability of neutrophils stimulated with beta-1,3-D-polyglucose derivatives to kill large numbers of bacteria could be overcome by a combined treatment with purified IL-1 or TNF in addition to beta-1,3-D-polyglucose derivatives. By incubating unstimulated cells with medium from beta-1,3-D-polyglucose-treated human peritoneal macrophages, the bactericidal activity of the cells was enhanced to the same extent as cells pretreated with purified TNF and IL-1. Cells incubated with IL-1-depleted medium from beta-1,3-D-polyglucose-treated human peritoneal macrophages, showed reduced bactericidal activity compared to cells incubated with undepleted medium. These studies demonstrate that beta-1,3-D-polyglucose-treated mononuclear phagocytes and neutrophils show enhanced bactericidal activity. The enhanced activity is partly caused by stimulation of the cells with IL-1 released from mononuclear phagocytes and partly by other unknown effects of beta-1,3-D-polyglucose derivatives on both mononuclear phagocytes and neutrophils.


The patterns and transmissibility of antibiotic resistance among clinical strains of Pseudomonas aeruginosa. Four hundred and ninety-eight predominantly pyocin-type 10 clinical strains of Pseudomonas aeruginosa were analyzed for resistance to carbenicillin, cefoperazone, cefotaxime, ceftazidime, gentamicin, amikacin and netilmicin. Based on NCCLS-recommended MIC breakpoints, 245 strains were found to be resistant, of which 41.6% were resistant to carbenicillin, 38% to gentamicin, 37.8% to netilmicin, 26.3% to cefoperazone, 17.9% to cefotaxime, 0.6% to amikacin and none to ceftazidime. Quadruple resistance to carbenicillin, cefoperazone, gentamicin and netilmicin was the most frequent pattern observed. Resistance to older antibiotics (kanamycin, streptomycin and tetracycline) and to mercuric chloride were also common. Conjugation experiments suggested that self-transmissible and non-transmissible plasmids occurred in at least 66 strains.


cDNA cloning of an aspartic proteinase secreted by Candida albicans. cDNA of an aspartic proteinase secreted by Candida albicans No. 114 was isolated using the polymerase chain reaction (PCR). The primary structure of the enzyme was deduced from the nucleotide sequence of the cDNA and compared with the structures of Saccharomyces cerevisiae proteinase A and vacuolar aspartyl proteinase of C. albicans. The mature aspartic proteinase consisted of 341 amino acid residues, and was 17.6 and 15.3% identical with the proteinase A and the aspartyl proteinase, respectively. Two active aspartic acid sites and the amino acids near those sites were conserved in the aspartic proteinase. We also showed that there is another gene of aspartic proteinase than that of strain ATCC10231 reported by Hube et al (J. Med. Vet. Mycol. 29 (1991)) in the same C. albicans genome, both in that strain and in No. 114.


Commentary on the possible effect of hormones in food on human growth. A change in the shape and size of young Americans' heads has been empirically observed with, specifically, a tendency toward dolicocephalic and smaller heads. It is known that hormones in food are likely to affect the growth process. In recent decades this factor distinguished the diet of Americans from the diet of Europeans. It is suggested that the general acceleration of growth in the most recent American generation could have been caused by accumulated hormonal residues in diet. The general acceleration of growth caused by hormones affects long bones more than any other tissue, and it triggers inhibitors of growth during earlier stages of flat bone development. Because of that, the relative size of the skull (flat bone structure) with respect to the body is diminished. This change of body/head proportion could be accompanied by a diminution in the absolute size of the skull as well.


Pregnancy and breast cancer: a possible explanation for the negative association. We propose that pregnancy protects against breast cancer, in part, because it results in excretion of lipophilic carcinogens by the mother through the fetal fat and vernix caseosa. We review several lines of epidemiologic and toxicologic evidence in support of this idea, including concordances between known or suspected risk factors for cancer of the female breast and known or suspected risk factors for increased body burdens of lipophilic carcinogens.


An update of the zinc deficiency theory of schizophrenia. Identification of the sex determining system as the site of action of reproductive zinc deficiency. The following article updates the GZD theory of schizophrenia (1) by showing that male transmission of risk, the parental age effect, racial differences in birth seasonality, the disturbed sex ratios in the offspring of schizophrenic mothers and the association between diabetes and schizophrenia are explained by changes to zinc homeostasis. A genetic component to the disorder is now seen as unnecessary, transmission of risk by either parent, and twin concordance differences can be explained by other means. The primary site of action of GZD is identified as the putative ZFY sex determining system. Evidence suggesting that other mental disorders might be caused by GZD is also discussed.


Vitamin C--the primate fertility factor? The loss of the ability of primates and man to synthesise ascorbic acid (vitamin C) is usually seen as an evolutionary accident, with no benefit to the species. This paper argues that the loss of this biosynthetic ability has allowed vitamin C to act as a 'fertility factor' in primate societies. It is argued that the requirement for vitamin C increases with age, and so in times of food shortages the older members of society suffer higher mortality than the younger. This reduces the median age of the population towards the younger and most fertile members, and so enables the population to regrow rapidly when food resources are restored.


Mechanism of general adaptation.

Mechanism of general adaptation. An analysis of theories and results of corresponding studies indicate that the adaptive processes in organisms have to be discriminated to specific and nonspecific adaptive responses. The integrated sum of specific adaptive responses constitute homeostatic regulation in order to maintain a constant level of rigid constants of the body's internal milieu. The constancy of rigid constants (temperature, pH, osmotic pressure, and contents of ions, water and p0(2)) is necessary to ensure the optimal activity of enzymes. The nonspecific adaptive responses are directed towards the mobilization of the organism's reserves for energy and protein synthesis. Additionally, a general activation of the body's defence faculties is included into the nonspecific adaptive responses. The nonspecific adaptive responses constitute a coordinated mechanism of general adaptation. The mobilization of the reserve for protein synthesis is connected with induction of the adaptive synthesis of the enzyme and structural proteins in order to restore and develop the functional capacity of cellular structures that were highly active during acute influence of various stressors.


The origin of the mammalian brain as a case of evolutionary irreversibility. The origin of the mammalian neocortex is usually considered as an improvement in the design of the brain. I suggest that the mammalian neocortex arose as a consequence of contingent adaptations in which there was no specific selection for more elaborate cognitive abilities. This perspective differs from the current view of brain evolution as a progressive phenomenon towards increased intelligence.


An electromagnetic theory of life--II: Testing. Serious problems and contradictions face the long-standing chemical reaction theory of life. Arguments favoring an alternative view featuring electromagnetic micromechanisms were presented in the December 1989 issue of this Journal (27, 31). However, the theory had an extremely general form which was forbidding to laboratory demonstration. It became clear that its essentially conceptual form needed to be transformed to a testable theory which ultimately could lead to laboratory verification. Now, with the recognition of the role of chaos theory in finding order within chaos in the kinetics of cell metabolism, the electromagnetic theory of life has become better grounded and more amenable to laboratory testing and evaluation. I thus focus on certain theoretical advances as well as the application of new technologies to test the hypothesis of 5 specific target areas. With the verification of electromagnetic processes in life, we anticipate that the biomedical sciences will be propelled to a wealth of solutions to many vexing problems.


On consciousness: what is the role of emergence? Can consciousness be understood as the ongoing active creation of information (of meaning)? 'Emergence', the central concept in this hypothesis, plays an essentially different role in it than in theories previously proposed.


Energy transformations in the biosynthesis of the immune system: their relevance to the progression and treatment of AIDS. Dysfunction of the immune system is observed in diseases where metabolic respiration is inhibited. Anabolites that enhance oxidative phosphorylation will provide the ATP essential for the biosynthesis of the cellular components and antibodies of the immune system. The induction of Coenzyme Q10 has been observed to protect against tumor growth and to enhance viral immunity in experimental animals. In a pilot study in AIDS patients the energy mediating catalyst elicited remarkable improvement. Additional cellular respiratory stimulants are considered as palliative synergists designed to enhance immunity in HIV infection. Competing antagonists to metabolic respiration acting to negate the effect of F delta in mediating optimal immune response to HIV are evaluated.


Are sense-antisense peptide interactions between HIV-1 (gp120), CD4, and the proto oncogene product p56lck important? The finding that codons for hydrophobic and hydrophilic amino acids are generally complemented by codons for hydrophilic and hydrophobic amino acids respectively has led to a novel observation. The antisense peptides coded for by the complementary DNA strand of biologically active peptides are able to bind their active sense counterparts with high specificity. Sense-antisense relationships have been observed in several peptide species as well as in receptor-ligand interactions. The idea that sense-antisense interactions are biologically relevant and indeed feasible among complex molecules prompts the examination of virus-host cell interactions. We propose such a sense-antisense interaction exists between the HIV glycoprotein gp120 and the intracellular domain of the HIV receptor CD4. This interaction is at a site which may be occupied by the proto oncogene product p56lck.


Serotonin-GABA treatment is hypothesized for self-injury in Lesch-Nyhan syndrome. The self-injurious movements of Lesch-Nyhan patients are considered extremely severe and currently intractable. Lesch-Nyhan syndrome is a genetic disorder of purine metabolism resulting in several abnormalities, one of which is elevated levels of xanthine. The author reasons that elevated plasma xanthine sets off a chain of events that produce excessive endogenous convulsants and diminished endogenous anticonvulsants. Treatment is proposed for self-injury in Lesch-Nyhan that entails reducing production of two endogenous convulsants (kynurenine and quinolinic acid) and enhancing two endogenous anticonvulsants (serotonin and gamma aminobutyric acid).


Is erythema toxicum neonatorum a mild self-limited acute cutaneous graft-versus-host-reaction from maternal-to-fetal lymphocyte transfer? Erythema toxicum neonatorum (ETN) is a common, self-limited neonate dermatosis affecting worldwide about 50% of newborns--mostly second and later deliveries--irrespective of sex and race. Its etiology still remains obscure: some reaction of the skin of the newborn in adapting to its new environment is the favorite hypothesis to date. A suggested viral or allergic nature could not be confirmed by adequate agent or antigen isolation respectively. In this paper a hypothesis is presented that ETN is a self-limited acute cutaneous graft-versus-host reaction (GVHR) caused in the transiently immunosuppressed newborn by maternal lymphocytes transferred shortly prior to or during delivery.


Compartmental syndrome in Duchenne muscular dystrophy: early evaluation of an epiphenomenon leading to wasting, weakness and contracture. Elevation of intracompartmental calf pressure in Duchenne Muscular Dystrophy can cause compartmental syndrome which accelerates mechanical muscle damage. Relief of increased pressure by fasciotomy inhibits this process. Intermittent pressure monitoring may prove of value in the routine orthopaedic management of patients with this disease. A historically controlled study to determine long term clinical benefit is in progress.


Seasonal birth distribution of west European soccer players: a possible explanation. Twice as many top soccer players from The Netherlands, Belgium and France are born in August, as compared to July. A creeping selection mechanism, inadvertently caused by organisational aspects of the youth soccer competition in the countries mentioned, could be the explanation.


High-dose flunitrazepam anesthesia.

High-dose flunitrazepam anesthesia. Benzodiazepines have receptors in the nervous system as well as in the kidney, liver, skeletal and ileal muscle, lungs and the heart. Flunitrazepam is a benzodiazepine with pronounced hypnotic effects in the usual dosage. High dose flunitrazepam anesthesia is suggested for prolonged surgical procedures as an alternative to the well known high-dose opiate anesthesia. Its reversal using flumazenil can shorten the post-operative anesthetic effect.


Commitment reversion model of unrestricted cell growth. Through the analysis of accumulated experimental data of cell growth, a model of unrestricted cell growth is presented here. This model is based hypothetically on the cellular commitment to senescence as in the previously presented commitment theory. Cells are divided into 3 types, namely uncommitted cells, committed cells and terminal cells. The division of an uncommitted cell produces an uncommitted cell itself and a committed cell of the first generation. This committed cell goes through a limited number of cell divisions until the cells become non-dividing terminal cells. It is hypothesized that during a committed cell division, there is a very small probability that an uncommitted cell may be generated. With computer simulations, it is estimated that a committed cell of the first generation may divide around 30 times until they become non-dividing terminal cells, and that the probability of an uncommitted cell regeneration for each committed cell division may be 2(-H). This hypothesis may possibly clarify some aspects of the biological phenomena of cell growth, which can not be explained by the previous commitment theory, such as the growth pattern of cultured diploid cells, cancer initiation and promotion, and cancer progression and metastasis.


Prevalence of malnutrition among children in an urban squatter settlement in Petaling Jaya. In a study of mild to significant malnutrition in an urban squatter settlement, the weights for age of 297 children between birth and ten years, and the heights for age and weights for height of 197 children between two to ten years were analysed. Using NCHS standards, the overall prevalence of underweight was found to be 18.9%, stunting 15.2%, and wasting 11.2%. Age and ethnicity were significantly associated with the prevalence of underweight and stunting. The growth achievement of children below the age of two years were significantly better off than the older children, and Chinese children significantly better off than Malay and Indian children.


Dose requirement and effect of nicardipine on lipid profile in mild to moderate essential hypertensives. Twenty eight patients who satisfied the entry criteria and had completed an initial 2 weeks treatment with placebo were titrated fortnightly with doses of Nicardipine ranging from 30 mg to 90 mg daily in two or three divided doses. Nicardipine treatment significantly reduced blood pressures both in the supine and standing positions (p < 0.0004) when compared with placebo treatment. Heart rates however did not change significantly. Forty six percent (13/28) of patients on 20 mg twice daily, 25% (7/28) on 10 mg three times daily, 18% (5/28) of patients on 20 mg three times daily and 11% (3/28) on 30 mg three times daily achieved supine diastolic blood pressures < 90 mm Hg. Nicardipine treatment at 16 weeks and at 24 weeks did not significantly alter the lipid profile when compared to the end of placebo treatment period. No other biochemical abnormalities were reported during the study period. Except for 2 cases of mild pedal oedema and 2 cases of transient headaches, no serious side-effects were encountered.


Comparative study of plain-film radiographs of maxillary sinuses between radiologists and clinicians. Maxillary sinuses plain film radiographs of 59 patients were reviewed and reported by both clinicians or Radiologists at the University Hospital, Kuala Lumpur. There was agreement in 52 reports of the plain film radiographs however there was partial differences in about seven cases. This gave an impression that the ENT specialist and the Radiologist were both capable of reporting plain film radiographs of maxillary sinuses, even though the radiologist has no opportunity of doing detail clinical examination of the patient.


Risk factor awareness and expectations of outpatients attending the Cardiology Clinic, Universiti Kebangsaan Malaysia. One hundred consecutive patients attending the UKM (Universiti Kebangsaan Malaysia) Cardiology Clinic completed a questionnaire enquiring about their own assessment of their knowledge about their illness, their awareness of cardiac risk factors and their expectations in their management. Only 11% of our patients had graduated from tertiary education. 59% of our patients were being treated for ischaemic heart disease. Although only 28% of our patients considered having considerable knowledge of their illness, a majority of our patients were aware of cardiac risk factors. This was independent of the formal education achieved. However this awareness did not necessarily result in appropriate behaviour; 32% of patients admitted to smoking despite being aware of the harmful effects of smoking. 74% of our patients expected a cure from their doctors; only 37% of our patients thought they required medication indefinitely. Thus, patients could be made aware of their illness regardless of their formal educational status. However this may not necessarily result in appropriate behaviour. The high expectations which the patients have of their doctors is unrealistic and may be detrimental to appropriate long-term management of their chronic illness.


Prevalence of peptic ulcer in 82 Kelantanese Malaysians with non-alcoholic cirrhosis. A review of 82 (68 male) Kelantanese patients with non-alcoholic cirrhosis who underwent gastroduodenal endoscopy revealed duodenal and gastric ulcers in 4.9% and 7.3% of patients respectively. Comparing with prevalence rates of peptic ulcer disease reported in the literature, there was no evidence to suggest that duodenal ulcers occur more frequently in patients with non-alcoholic cirrhosis. There is a suggestion, albeit a tenuous one, that non-alcoholic cirrhosis may be associated with gastric ulceration.


Perforating eye injuries due to intraocular foreign bodies. The results of sixty-four perforating eye injuries with intraocular foreign bodies (IOFB) treated at University Hospital over ten years were reported. Compared to an earlier report we found that the population at risk was the same and consisted of patients under 35 years (70%), males (95.3%) and work related (86%). The commonest causes of IOFB were hand hammer (64.1%) and grass cutting (20.3%). We also noted that while the incidence of cases had increased by 23%, the final visual outcome has improved significantly due to advances in preoperative diagnosis and surgical techniques. Preoperative factors found to have a statistically significant effect on the final visual outcome were the size of the IOFB, poor initial visual acuity, and the presence of the following complications: cataract, iris damage and vitreous haemorrhage. The outcome was also worse in posterior segment IOFBs but this was not statistically significant.


Results of meniscal surgery of the knee. From 1988 to 1990, eighty operations on eighty knees of seventy-nine patients with a clinical diagnosis of meniscal tear was entered into a prospective study. The clinical diagnosis was correct in 76% of patients. Excellent or good results were achieved in 90% of knees which had only meniscal lesions but dropped to 70.5% when other intraarticular pathologies coexisted with the meniscal lesions. Excellent or good results were achieved in 71% of the knees in the presence of Anterior Cruciate Ligament (ACL) deficiency.


All trans-retinoic acid in the treatment of promyelocytic leukaemia--a case report. A six year old Chinese boy with relapsed Acute Promyelocytic Leukaemia (APML) failed to respond to reinduction with Daunorubicin and Cytarabine infusion. He was successfully treated with all trans-Retinoic Acid (45 mg/m2/day) orally. After four weeks of treatment, he was in complete remission. The side effects of all trans-Retinoic Acid were negligible.


Prenatal diagnosis of intestinal obstruction due to ileal atresia. A case of intestinal obstruction due to ileal atresia where the diagnosis was made prenatally by ultrasound is presented. Close monitoring of the fetus was done ultrasonographically to look for any evidence of meconium peritonitis. The baby was delivered preterm but weighed 3.3 kg. Laparotomy and enterostomy was done and the baby is currently well.


Cassava (ubi kayu) poisoning in children. Three sisters with cassava poisoning are described. A review of the toxic properties of cassava is presented together with discussion on the methods of its preparation, its adverse effects on man, its detoxification in the body, and the treatment of its poisoning.


[Bone clefts of the median facial structures. An anatomical study]. After reviewing the literature concerning rare facial fissions, the authors describe the skull of a young woman with an incomplete bone fission of the median facial structures. They focus on the associated bone anomalies observed in the skeleton of the nose and upper jaw.


[The importance of direct immunofluorescence in the diagnosis of oral lichen planus. A clinical study and proposal of new diagnostic criteria]. A series of 40 lesions of various kinds as lichen planus are examined using samples stained with trichromic test. HLA-DR expression with immunoperoxidase technique and direct immunofluorescence using the standard techniques. The aim of the study was to discover the usefulness for diagnosis of direct immunofluorescence, above all in histologically uncertain cases. The results suggest the view that direct immunofluorescence is essential for diagnosis of lichen planus, in all clinical aspects. The author concludes with description of clinical proceeding for differential diagnosis between white and erosive lesions of mouth.


[The anthropomorphic proportions of the face: an evaluation of the response to orthodontic surgical treatment of Angle class III]. The purpose of this investigation was: to examine the anthropometric facial presurgical and postsurgical indices of patients having a dento-skeletal class III malocclusion and who were treated with the orthodontic-surgical procedure. To evaluate the postsurgical response of the soft tissues, according to the type of approach: mandibular surgery or maxillo-mandibular surgery. To recognize, if it is possible, what indices are to be considered more involved in the esthetic change. Ninety pre and postoperative frontal photographs of 45 subjects were studied. The subjects were 32 females and 15 males who had a dento-skeletal class III malocclusion and who had undergone the orthodontic-surgical treatment (21 had sagittal bilateral mandibular osteotomy, 24 had sagittal bilateral mandibular osteotomy + Le Fort I). The photographs were taken with lips in repose, relaxed soft tissue and centric occlusion. The mean age of the patients was 23 years (ranging 16-35). The post-treatment follow-up went from 1 to 3 years. 11 frontal landmarks: n = nasion, sn = subnasale, sto = stomion, sl = sublabiale, gn = gnathion, go = gonion (bilateral), zy = zygoma (bilateral), ch = cheilion (bilateral) were recognized and 3 horizontal and 5 vertical measurements were taken: zygomatic width (zy-zy), mouth width (ch-ch), gonial width (go-go); face height (n-gn), lower face height (sn-gn), upper face height (n-sto), height of lower third of the face (sto-gn), medial vertical chin height (sl-gn). 11 pre and post-treatment facial indices were obtained from the ratio per cent of the measurements previously mentioned using the method of Farkas: Facial (n-gn-zy-zy), Mandible-face width (go-go/zy-zy), Upper face (n-sto/zy-zy), Mandible width-face height (go-go/n-gn), Mandibular (sto-gn/go-go), Mouth face width (ch-ch/zy-zy), Lower face-face height (sn-gn/n-gn), Mandible face height (sto-gn/n-gn), Mandible-upper face height (sto-gn/n-sto), Mandible-lower face height (sto-gn/sn-gn), Chin-face height (sl-gn/sn-gn). In each patient the mean values, with their standard deviations, were calculated according to the sex for each index. A different group of average values was calculated according to the sex and to the type of surgical approach; 17 females and 4 males underwent a mandibular setback osteotomy and 15 females and 9 males underwent a sagittal bilateral mandibular osteotomy + Le Fort I osteotomy.(ABSTRACT TRUNCATED AT 400 WORDS)


[Cyclosporin in a bioadhesive formulation in the therapy of oral erosive lichen planus. A clinico-experimental evaluation]. This study illustrates the possible topical therapy of OLP with cyclosporine A under bioadhesive gel formula. The treatment was carried out on 6 patients for 8 weeks in much lower (48 mg/day) than those used by other authors. The novelty of this study lies in the use of a bioadhesive formula with carbosymethylcellulose which allows CsA to remain on oral mucosa for about two hours. The remarkable results have shown a reduction ranging from 50 to 80% of oral lesions, thus proposing its specific use in all the forms resisting usual therapy.


[Diabetic disease and periodontal disease. Diabetes and periodontopathy]. Diabetic patients have been reported to be more susceptible to gingivitis and periodontitis than healthy subjects, and these diseases are commonly considered to be oral complications of diabetes. The influence of diabetes on the onset and development of periodontal disease has been studied for many years but clear agreement is still lacking on the nature of the relationship between diabetes and these oral disorders. In fact recent observational epidemiological studies suggest that diabetes should not be considered as the direct cause of periodontal disease but rather as a systemic promoting factor, able to produce conditions suitable for local agents producing gingivitis and periodontitis. The overriding oral problem in diabetes is infection, like with any of the dermal lesions in the diabetic. In fact periodontal disease is caused by specific bacteria (Bacteroides Gingivalis, Actinobacillus actinomycetemcomitans) growing in the periodontal pocket so that the bacterial products such as histolytic enzymes, endotoxins or exotoxins may exert a direct effect. Particular attention has been directed to the neutrophils and to their role in antibacterial defense. In fact a reduced phagocytosis, leukotaxis and leucocyte index have been reported in neutrophils from diabetics. The careful metabolic control was reported by most of the Authors to lower the incidence and to reduce the severity of periodontal disease. This may be related both to the improvement in leukocyte function and to a change in gingival fluid rendering it less suitable for bacterial growth. In diabetics also local factors, such as decreased pH of salivary fluid and a reduced salivary flow, seem to play an important role.(ABSTRACT TRUNCATED AT 250 WORDS)


[The role of biopsy of the minor salivary glands in the diagnosis of Sjögren's syndrome]. After a short critical review of the latest literature, the authors evaluate the role of minor salivary gland biopsy in the diagnosis of Sjögren's syndrome. The histological factors typical of this syndrome are examined in this context.


[Epidemiological studies of the dental-periodontal health conditions in 2 samples of the school-age population of the city of Turin]. The paper reports the results of a study of the prevalence of teeth-parodontal diseases found in two groups from the school population, aged between 13 and 19, resident in Turin. The structure of the survey, the clinical methods of collecting data and the statistical processing of data were carried out according to OMS directives regarding the study of oral pathologies.


[A case of a carcinoma arising in lichen planus in a subject with diabetes mellitus and arterial hypertension (Grinspan's syndrome)]. The authors describe a clinical case observed at the Inst of Oral & Maxillofacial Surgery characterized by three simultaneous symptoms: arterious hypertension, diabetes mellitus, oral erosive lichen planus. Grinspan & his co-workers observed this syndrome. The results of their research were exposed at the Congress on Dermatology in Buenos Aires, 1963. In 1965 in a repetitive study Grupper & Avul seemed confirm the existence of this symptomatological triad; therefore the authors defined this complex as "Grinspan's syndrome". Further researches conducted by other authors (Jolly, Powell. Howell e Rick) confirmed the association hypertension-diabetes-"erosive" lichen. However there were other worthwhile studies (Lozada-Nur, Christensen) which emphasized a not significant high frequency of patients with diabetes and high blood pressure and the oral sugar tolerance like random specimens of common people. Besides the authors notice that their clinical case is interesting not only because of their simultaneous presence of the three symptoms but also because of the bioptic appearance of a cancer likely appeared on a pre-existing inveterate lichenoid lesion.


Bilirubin encephalopathy in a term infant after planned home delivery. A term infant was delivered at home by his father after a pregnancy which involved no organized medical care. By the third day of life the infant developed fever, poor feeding and severe jaundice. The infant was found to have a serum indirect bilirubin of 49 mg/dl secondary to isoimmune hemolytic anemia due to anti-c antibody. The infant survived but suffers from clinical manifestations of kernicterus.


Tetanus surveillance--United States, 1989-1990. During the period 1989-1990, 117 cases of tetanus were reported from 34 states, for an average annual incidence of 0.02/100,000 population. Fifty-eight percent of patients were > or = 60 years of age, while seven (6%) were < 20 years of age, including one case of neonatal tetanus. Among adults, the risk of tetanus in those > 80 years of age was more than 10 times the risk in persons ages 20-29 years. The case-fatality rate increased with age, from 17% in persons 40-49 years of age to 50% in those > or = 80 years of age. Only 11% of patients reported having received a primary series of tetanus toxoid before disease onset, while 31% lacked a history of tetanus vaccination. Tetanus occurred following an acute injury in 78% of patients. Of patients who sought medical care, only 58% received tetanus toxoid as part of wound prophylaxis. Tetanus remains a severe disease that primarily affects unvaccinated or inadequately vaccinated older adults. Increased efforts are needed to reduce the risk of tetanus among the elderly. Health-care providers should take every opportunity to review the vaccination status of their patients and provide tetanus vaccine when indicated.


Pertussis surveillance--United States, 1989-1991. The licensure of whole-cell pertussis vaccine combined with diphtheria and tetanus toxoids as DTP in the 1940s--and its widespread use in infants and children--led to a dramatic decline in the incidence of reported pertussis. In the prevaccine era, the average annual incidence and mortality for reported pertussis were 150 cases and six deaths per 100,000 population, respectively. From 1989 to 1991, pertussis cases were reported by state and local health departments to CDC through two distinct national surveillance systems: the National Notifiable Diseases Surveillance System (NNDSS) and the Supplementary Pertussis Surveillance System (SPSS). During the period 1989-1991, 11,446 pertussis cases were reported to the NNDSS (4,157 in 1989; 4,570 in 1990; and 2,719 in 1991), for an unadjusted annual incidence of 1.7, 1.8, and 1.1 cases per 100,000 population in 1989, 1990, and 1991, respectively. For the period 1989-1991, case reports were received through the SPSS on 9,480 (83%) of the 11,446 patients reported to the NNDSS. Age-specific incidence and hospitalization rates were highest among children < 1 year of age and declined with increasing age. Long-term trends suggest an increase in the reported incidence of pertussis in the United States since 1976. The peak in reported pertussis cases in 1990 represents the highest annual incidence of pertussis since 1970. However, the incidence of pertussis declined 41% from 1990 through 1991. Whether the long-term increase in reported pertussis is a true increase in incidence is unclear; the observed increase may be a function of improved surveillance.(ABSTRACT TRUNCATED AT 250 WORDS)


[Simulated modeling of biopolymer molecular structure]. A simple approach for simulation of structure of biopolymers and their complexes is developed, including methods for conformational analysis "in vacuum" and methods for estimation of free energy of transfer between organic phase and water, evaluating hydrophobic interactions. The possibilities of the described methods are demonstrated by the simulation of the structure of C60-hydrocarbon polymer and glycine and alanine peptides.


[De novo proteins with a given spatial structure: new approaches to design and analysis]. Based on the molecular theory of protein structure the de novo protein was designed in order to obtain the tertiary fold which has not yet been observed in natural proteins, namely four-stranded antiparallel beta-sheet covered by two alpha-helixes. The gene coding for this protein (named albebetin) was chemically synthesized, cloned in plasmid with SP6 phage promoter and expressed in mRNA-dependent cell-free translation system. An approach was developed to study albebetin using only nanogram amounts of radio labelled protein without previous purification. The preliminary analysis of its structure by gel-filtration, urea-gradient electrophoresis and limited proteolysis revealed compactness and stability of the de novo protein.


[Electron-conformational interactions at the active site of reduced bacterial cytochrome P450cam induced by a substrate and analysis of the electron structure of heme]. Magnetic circular dichroism (MCD) spectra in the Soret region (360-480 nm) of camphor-free and camphor-bound reduced bacterial cytochrome P450cam from Pseudomonas putida were recorded and analysed in the temperature range from 2 K to 290 K. The temperature dependences of the MCD intensity are qualitatively changed by binding of substrate to the enzyme. In the absence of camphor the linear increase of the MCD intensity with 1/T at T < 4.2 K gives evidence for degeneracy or near degeneracy of the ground electronic state. In the presence of substrate the degeneracy is removed and temperature profiles show saturation behaviour at T < 4.2 K and wavelength dependence of their high-temperature parts. The temperature profiles for the long-wavelength region of the Soret band have a maximum approximately at 15 K, whereas the MCD intensity increases in a monotonous manner up to saturation in the short-wavelength region. The wavelength dependence of temperature profiles gives evidence for the co-existence of two different forms of substrate-bound reduced P450cam. The following conclusions were obtained from a theoretical analysis of the temperature profiles. In the absence of substrate there are very small if any rhombic distortions at the heme iron, and a parameter D of axial zero-field splitting is negative (D = -8.3 cm-1 and -6.2 cm-1 for P450cam and P450LM2, respectively). In the presence of substrate the two forms of reduced P450cam have positive parameters D but of different values (D1 = 12 cm-1 and D2 = 28 cm-1), and there are large rhombic distortions at the heme iron. More than two-fold difference between the D values made it possible to isolate temperature-dependent contributions of the two enzyme forms from the total MCD spectra and to simulate the alterations of the MCD spectra with temperature for reduced P450cam in the presence of substrate. Taking into account the drastic effect of substrate binding on the ground electronic state of reduced P450cam one can suggest that substrate binding induces the transition of enzyme from an inactive to an active state.


[SLS--a new type of polynucleotide chain folding]. Short tandem repeats (5-8 base pairs) are not uncommon in the prokaryotic and eukaryotic DNA. Regions with such sequence motifs, when under superhelical stress, manifest unusual sensitivity to single-strand specific nuclease. To explain this, it has been suggested that one DNA thread should be shifted relatively to another, so that they could form two single-stranded loops protruding from the opposite chains and separated on the DNA helix by the length of a direct repeat. The structure was proposed to play a role in the regulation of transcription, organization of chromatin and in the recombination. Such type of folding could have been extra-stabilized by base pairing between the loops. This attractive possibility of the interloop minihelix formation requires a delicate stereochemical analysis and direct experimental support. Formation of the interloop minihelix in the Slipped Loop Structure (SLS) was tested by a chemical modification method at one nucleotide level resolution. The results show that bases located within the proposed interloop helix are well protected from the probes used. This fact encourages us to publish a 3-D model for the SLS-form DNA (and RNA). The SLS is characterized by a remarkable symmetry having three mutually perpendicular dyad axes. Scanning the bank of nucleotide sequences has revealed more than 500 sites, the transcripts of which are capable of folding into the SLS form, which allow us to regard the SLS form as a novel universal structural form. Remarkably, the abundance of SLS in intrones three times exceeds that of the coding sequences. This may reflect a functional role (or roles) of the SLS conformation.


[DNA sequencing by hybridization with an oligonucleotide matrix (SHOM). The theory of DNA elution after hybridization]. The theoretical treatment of the process of washing out of a single stranded DNA fragment after hybridization with short oligonucleotides immobilized within the polyacrylamide gel layer is presented. The theory describes satisfactorily the main body of experimental findings, obtained earlier in connection with the elaboration of a new DNA sequencing method based on hybridization with the matrix of immobilized oligonucleotides [K.R. Khrapko et al.@J. DNA Sequencing Mapp. 1991. V. 1. P. 373-388]. In particular the theory explains and describes well quantitatively the observed dependence of the "washing off temperature" Tw on the concentration of the immobilized oligonucleotides. The Tw dependence on inherent physico-chemical parameters such as the enthalpy and the entropy of duplex formation and on those selected by the experimenter (washing time duration, the gel thickness etc.) is also considered. A simple approximate expression for the calculation of "washing off temperature" is given. Some inconsistencies between calculated and observed washing curves are discussed.


[A triple-stranded "clip" from the oligonucleotide 3'-(dA)10-pO(Ch2Ch2O)3p-(dT)10-pO(CH2CH2O)3-p-(dT)10(-5)]. The temperature dependence of the UV- and CD-spectra of the oligonucleotides 3'-d(A)10-L-(T)10-5' [anti(AT)], 3'-d(A)10-L-d(T)10-3' [par(AT)] and 3'-d(A)10-L-(dT)10-L-(dT)10-5' [tripl(ATT)] (L = -PO(CH2CH2O) 3p-) in the phosphate buffer at pH 7 under different concentrations of NaCL and in the presence or absence of 0.01 M MgCl2 was studied. All registered structural changes are the result of intramolecular processes if the concentrations of the oligonucleotides is low (about 2.2.10(-5) M). Par(AT) and anti(AT) exist in the only two forms, transforming into each other: under low temperatures they exist as hairpins with the parallel or antiparallel orientation of chains accordingly which transform into unfolded chains when the temperature increased. In contrast trip(ATT) exists in the three different forms depending on the temperature and ion conditions. They are: the three- stranded clip, the two-stranded hairpin with a single stranded "tail" and completely unfolded chain. For the first time this work presents thermodynamic parameters of the triplex formation from deoxyoligonucleotides depending on NaCl concentration. We have registered the CD spectra to one-, two-, and three-stranded forms. Ethidium bromide binding to three-stranded "clip" was investigated, and it was established that molecules of the dye may intercalate into the "clip" with formation of stable complexes (the constant of association 10(6) M-1). It is maximum three molecules of ethidium bromid which may bound to one molecule of the three-stranded clip. It has been shown that the suggested synthetic model (three oligonucleotide blocks combined by hydroxyalkyl chains) is the most convenient for physico-chemical investigations of triplexes today.


[Parallel DNA helices. Conformational analysis of regular poly(dG).poly(dC) helices with different variants of base binding]. We have performed a conformational analysis of DNA double helices with parallel directed backbone strands. The calculations were made for homopolymers poly(dG).poly(dC). All possible models of base binding were checked. By the potential energy optimization the dihedral angles and helices parameters of stable conformations of parallel double polynucleotides were calculated. The dependences of conformational energy on the base pair structure were studied. Possible structure of parallel helices with various nucleotide composition are discussed.


[Extracellular alkaline ribonuclease of Bacillus thuringiensis var. subtoxicus]. Intraspecific selection of Bacillus thuringiensis strains producing extracellular alkaline ribonucleases was carried out. Subtoxicus subspecies with increased expression of the enzyme was detected. A method was developed to isolate preparative amounts of homogeneous extracellular RNase of B. thuringiensis var. subtoxicus. The physico-chemical and catalytic properties of the enzyme was studied and compared with extracellular RNases of others Bacillus species. The conclusion about the structural and evolutional conservation of Bacillus extracellular RNases was drawn.


[Decomposition fluorescence spectra of tryptophan residues in proteins based on log-normal components by a least squares method]. An algorithm of decomposition of protein tryptophan spectra into components was developed. The spectral shape of components is described by a uniparametric log-normal function. Rise of certainty and accuracy of resolution of widely overlapping smooth spectral components (a typical uncorrect reverse problem) was achieved using several regularizing factors: (i) the set of experimental spectra used were measured at several quencher concentrations; (ii) the functional being minimized, along with the root mean square residuals of intensities, the term depending on the obedience to the Stern-Volmer law; (iii) an extra information is used--the number of experimental values greatly exceeds the number of parameters to be estimated. The minimum of functional is determined by a consecutive setting of all possible combinations of component spectral maxima values, which allows to avoid sticking in the local minima of noisy functional. The real experimental noise restricts the decomposition into not more than three components. The decomposition error does not exceed the experimental one. The algorithm functioning is illustrated by resolution of tryptophan fluorescence spectra of papain into one, two, and three components.


[Conformational transition of parallel DNA in solutions with decreased water activity]. Conformations of parallel deoxyoligonucleotides 5'd(CTATAGGGAT)3'/5'd(GATATCCCTA)3' and 5'd(TGATTGATCGATTGTTTGCATGCACACGTTTTTGTGAGCG)3'/'5'd (ACTAACTAGCTAACAAACGTACGTGTGCAAAAACACTCGC)3' were studied in solution by CD method. A cooperative change in the CD spectra is observed in trifluoroethanol (TFE) solutions at decreased water activity (relative humidity). This distinctive change is supposed to stem from a cooperative conformational transition of parallel double helix from a B-like form with C2'endo sugar conformation to a A-like form designated as Ap. The free energy difference between Ap- and B-like conformations of the parallel decaduplex is close to that for antiparallel decaduplex with the nucleotide sequence studied. A-phility of a parallel helix is dependent on its sequence.


[L-shaped structure from two alpha-helices with a proline residue between them]. L-shaped structures formed by two consecutive alpha-helices joined by short connections are considered. The L-structures with the alpha m gamma beta/delta alpha n-conformations are of particular value since they usually have Pro residues in the second positions of the second alpha-helices. These structures can be divided into two classes, the right-turned and left-turned L-structures, depending on whether the second alpha-helix is located on the right or the left, relative to the first one when viewed from the hydrophobic core. Stereochemical analysis shows that in an ideal case the left- and right-turned L-structures should have different sequence patterns of hydrophobic, hydrophilic and proline residues. These sequence patterns can be used in the prediction of the L-shaped structures as well as in protein design and engineering.


[Study of the dynamics of human serum albumin by coherent Rayleigh dispersion of Mossbauer radiation]. The measurements of angle dependencies of total and elastic Rayleigh scattering of Mossbauer radiation intensities have been performed for human serum albumin (HSA) with hydration degrees h = 0.13 and h = 0.4. The extended model was developed for calculating the inelastic intensity of Rayleigh scattering. Original data for HSA and published data on met-Mb were fitted within the frame of this model. The best agreement with experiment was obtained when two types of intraglobular motions were taken into account: individual motions of small side-chain groups and cooperative (mechanical) motions of segments (most probable alpha-helices). Long-range correlated motions are essential at low hydration degree. The possibilities of application of the coherent version of RSMS technique are described.


Mammary gland-specific nuclear factor activity is positively regulated by lactogenic hormones and negatively by milk stasis. The mammary gland-specific nuclear factor (MGF) is a crucial contributor to the regulation of transcription from the beta-casein gene promoter. The beta-casein gene encodes a major milk protein, which is expressed in mammary epithelial cells during lactation and can be induced by lactogenic hormones in the clonal mammary epithelial cell line HC11. We have investigated the specific DNA-binding activity of MGF in mammary epithelial cells in vivo and in vitro. Comparison of MGF in HC11 cells and mammary gland cells from lactating mice revealed molecules with identical DNA-binding properties. Bandshift and UV cross-linking experiments indicated that MGF in HC11 cells has a higher mol wt than MGF found in mice. Little MGF activity was detected in nuclear extracts from HC11 cells cultured in the absence of lactogenic hormones. Lactogenic hormone treatment of HC11 cells led to a strong induction of MGF activity. The induction of MGF activity as well as utilization of the beta-casein promoter were suppressed when epidermal growth factor was present in the tissue culture medium simultaneously with the lactogenic hormones. In lactating animals, MGF activity is regulated by suckling, milk stasis, and systemic hormone signals. The mammary glands from maximally lactating animals, 16 days postpartum, contain drastically reduced MGF activity after removal of the pups for only 8 h. The down-regulation of MGF by pup withdrawal was slower in early lactation, 6 days postpartum. We also investigated the relative contributions of local signals, generated by milk stasis, and systemic hormone signals to the regulation of MGF activity. The access to one row of mammary glands of lactating mothers was denied to the pups for 24 h. High levels of MGF were found in the accessible mammary glands, and intermediate levels of MGF were found in the inaccessible glands of the same mouse. Very low MGF levels were detected when the pups were removed from the dams for 24 h. We conclude that systemic as well as local signals cooperate in the in vitro regulation of MGF activity.


[Spatial structure of (1-36)bacterioopsin solubilized in a methanol-chloroform mixture with sodium dodecylsulfate micelles]. Spatial structures of proteolytic segment A (sA) of bacterioopsin of Halobacterium halobium (residues 1-36) solubilized in the mixture of methanol-chloroform (1:1), 0.1 M LiClO4 or in perdeuteriated sodium dodecyl sulfate (SDS) micelles, were determined by 2D 1H-NMR techniques. Most of the resonances in 1H-NMR spectra of fragment A were assigned using DQF-COSY, TOCSY and NOESY spectra. Deuterium exchange rates for amide protons were measured in series of NOESY spectra. 324 and 400 NOESY cross-peak volumes were measured in NOESY spectra of sA in mixture of organic solvents and SDS micelles, respectively. The sA structure was determined by local structure analysis, distance geometry calculation with program DIANA and systematic search for energetically allowed side chain rotamers consistent with NOESY cross-peak volumes. The structures of sA are similar in both milieus. These structures have the right-handed alpha-helical region from Pro-8 to Met-32 with root mean square deviation (RMSD) of 0.25 A between back bone heavy atoms and fit well with Pro-8 to Met-32 alpha-helical region in electron cryo-microscopy (ECM) model of bacteriorhodopsin [4]. The C-terminal region Gly-33-Asp-36 is disordered in both milieus, while N-terminal region Ala-2-Gly-6 in organic solvents has a fixed structure (RMSD of 0.25 A) stabilized by the Thr-5 NH...O=C Gln-3 and Ile-4 NH...O = C Ala-2 hydrogen bonds. This region of sA in SDS micelles has disordered structure with RMSD of 1.44 A for back bone heavy atoms. Torsion angles chi 1 of sA were unequivocally determined for 72% of side chains in the alpha-helical region and are identical in both milieus.