Methionine transport by pig colonic mucosa measured during early post-natal development. New-born pig proximal colon, incubated in vitro, transports methionine with a Km of 0-33 mM and a Vmax of 0-62 mumole cm-2h-1. There is still a net transport of methionine on day 4, but the Km now increases to 10 mM and the Vmax falls to 0-15 mumole cm-2h-1. There is no net transport of methionine across proximal colons taken from 10-day-old pigs. 2. The mean intramucosal concentration of methionine, following incubation in medium containing 1 mM methionine, is 7-18+/-0-8 mM for the new-born, 0-55+/-0-05 mM for the 4-day-old and 0-31+/-0-06 mM for the 10-day-old pig. 3. Both methionine and glucose cause an immediate increase in the short-circuit current of new-born and 1-day-old pig colons. The kinetics for this interaction with methionine gives a Km for methionine of 0-24 mM and a maximum effect of 27 muA cm-2. This effect is not seen in 4- or 10-day-old pigs. 4. Net Na+ transport across the new-born pig proximal colon, measured in the absence of methionine, is about three times that calculated from the measured short-circuit current. Methionine increases the mucosal to serosal flux of Na+ by an amount roughly equal to that predicted from the increase in short-circuit current. The ability of glucose and methionine to affect short-circuit current is lost by day 4. 5. Short-circuit current, measured in the absence of methionine or glucose, increases between day 1 and 2 of post-natal life. This increased electrogenicity is maintained for up to at least 10 days after birth. 6. The pig proximal colon has many of the properties of a small intestine at birth. It actively transports methionine and the presence of methionine stimulates the absorption of Na+. These effects could be physiologically important in the pig, where the normal absorptive function of the intestine is temporarily inhibited at birth by the intestinal transmission of immune globulins.


Electrical properties of pig colonic mucosa measured during early post-natal development. Microvillar membrane (Vm) and transmural (Vt) potential differences were measured in proximal colon taken from pigs at birth and up to 10 days of age. 2. Vm remained independent of the age of the animal provided it was measured in the absence of methionine. The over-all mean was -43-3 mV. Adding methionine to fluid bathing the mucosal surface of new-born pig colon caused a 9-8 mV depolarization of Vm and a 6-7 mV increase in Vt. These effects, which were Na+-dependent, were not seen in the 10-day-old animal. 3. Substituting SO4(2-) for Cl- in methionine-free medium caused a hyperpolarization in Vm. Increasing the concentration of K+ caused corresponding depolarization. Substituting choline for Na+ had no effect on VmCl- and K+ movement across the microvillar membrane together account for the bulk of the measured membrane potential. These results apply to all stages of development. 4. Na+ uptake across the microvillar membrane of the new-born pig colon was increased in the presence of methionine. This effect disappeared in older animals. Na+ uptake in the absence of methionine doubled during the first 24 h of post-natal life. This increase was maintained using colons taken from older animals. 5. Methionine depolarization of Vm in the new-born pig colon is probably caused by the electrogenic influx of Na+. The ability of the colon to actively concentrate methionine within tis mucosa disappears at the same time as methionine ceases to affect Vm and Vt. It is suggested that methionine and Na+ form a ternary complex with a carrier in the brush border of the new-born pig colon and that this carrier is lost or modified during early post-natal development.


Effect of regional alpha- and beta-adrenergic blockade on blood flow in the resting forearm during contralateral isometric handgrip. In a previous study we have shown that an isometric handgrip is accompanied by a rapid decrease in vascular resistance in the resting (contralateral) forearm, lasting for about 1 min, which in all probability is neurogenic. 2. In the present study the distribution of the vasodilatation was investigated by analysing O2 saturation in a deep vein, draining mainly muscle tissue. Some possible neurogenic mechanisms for the vasodilatation were tested by repeating the handgrip after local beta- and alpha-adrenergic blockade of the resting forearm with propranolol and phentolamine, respectively. 3. Without blockades the forearm vascular resistance decreased and the deep vein O2 saturation increase to similar degrees on contralateral handgrip. Propranolol markedly reduced both the decrease in resistance and the increase in deep vein O2 saturation. Phentolamine did not alter the initial decrease in resistance, but with phentolamine resistance continued to decrease after 1 min. 4. It is concluded that the rapid decrease in vascular resistance in the resting forearm on contralateral handgrip takes place, to a great extent, in muscle. It is mediated by neurogenic beta-adrenergic mechanisms and if the contraction is prolonged it gradually changes to a vasoconstriction mediated by alpha-adrenergic mechanisms.


Quantitative analysis of retinal ganglion cell classifications. The classification of cat retinal ganglion cells as X or Y on the basis of linearity or nonlinearity of spatial summation has been confirmed and extended. Recordings were taken from optic tract fibres of anaesthetized, paralysed cats. 2. When an alternating phase sine wave grating was used as a stimulus, X cells had null positions and Y cells responded at all positions of the grating. 3. These results did not depend on the temporal wave form or the temporal frequency of pattern alternation over a wide range. 4. At high spatial frequencies for the particular cell, a Y cell gave abig 'on-off' response, or frequency doubling, at all positions of the grating, while an X cell did not. 5. The use of contrast sensitivity versus spatial phase also served to differentiate the two cell types. With an alternating sine grating stimulus X cells had a sinusoidal dependence on spatial phase, while each Y cell's sensitivity depended in a complicated manner on spatial phase. 6. Sensitivity versus spatial phase for different Fourier components of the neural response also separated the two classes of cells. Significant second harmonic distortion was present in Y cells. The second harmonic component was spatial phase insensitive, and became dominant at high spatial frequencies. 7. The maximum of the 2nd/1st harmonic ratio was taken as an index of nonlinearity. X cells always had a nonlinearity index less than 1 while in Y cells this index always exceeded 1. 8. Response to spots, diffuse light and drifting gratings were compared to the nonlinearity index as a basis for classifying cells. The nonlinearity index was most reliable because it was least dependent on retinal eccentricity.


Linear and nonlinear spatial subunits in Y cat retinal ganglion cells. 1. The mechanism which makes Y cells different from X cells was investigated. 2. Spatial frequency contrast sensitivity functions for the fundamental and second harmonic responses of Y cells to alternating phase gratings were determined. 3. The fundamental spatial frequency response was predicted by the Fourier transform of the sensitivity profile of the Y cell. The high spatial frequency cut-off of a Y cell's fundamental response was in this way related to the centre of the cell's receptive field. 4. The second harmonic response of a Y cell did not cut off at such a low spatial frequency as the fundamental response. This result indicated that the source of the second harmonic was a spatial subunit of the receptive field smaller in spatial extent than the centre. 5. Contrast sensitivity vs. spatial phase for a Y cell was measured under three conditions: a full grating, a grating seen through a centrally located window, a grating partially obscured by a visual shutter. The 2nd/1st harmonic sensitivity ratio went down with the window and up with the shutter. These results implied that the centre of Y cells was linear and also that the nonlinear subunits extended into the receptive field surround. 6. Spatial localization of the nonlinear subunits was determined by means of a spatial dipole stimulus. The nonlinear subunits overlapped the centre and surround of the receptive field and extended beyond both. 7. The nature of the Y cell nonlinearity was found to be rectification, as determined from measurements of the second harmonic response as a function of contrast. 8. Spatial models for the Y cell receptive field are proposed.


Properties of a facilitating calcium current in pace-maker neurones of the snail, Helix pomatia. 1. Simultaneous measurements of local voltage clamp currents from patches of soma membrane and K activity at the soma surface were used to analyse the time and voltage dependence of the slow inward current in bursting pace-maker neurones of the snail (Helix pomatia). 2. At low levels of depolarization (less than or equal to mV) a net inward current is recorded simultaneously with an efflux of K ions from the cell. 3. With larger depolarizations (20-170 mV from holding potential of -50 mV) the deficit in net outward charge transfer compared with K efflux and the appearance of inward-going tail currents following repolarization, reveal a persistent inward-going current also under these conditions. This inward current is carried primarily by Ca ions, as demonstrated by its voltage dependence (a minimum at about + 115 mV) and its disappearance in Co-Ringer. It is identified with the slow inward Ca current Iin slow (Eckert & Lux, 1976). 4. The inward current predicted from comparisons of current trajectories reaches a maximum at 15-20 msec (for depolarizations from -50 to 0 mV) and gradually declines with sustained depolarization. 5. Partial inactivation is removed by repolarization to -50 mV and the Ca dependent deficit is greater in the sum of repeated voltage clamp pulses than during sustained depolarization. It is largest for pulses of 25-100 msec duration, decreasing as pulse duration increases. 6. Responses to repeated activation with 100 msec pulses with different repolarization intervals reveal a minimum Iin slow at short intervals (e.g. 20 msec) due to failure to remove partial inactivation. At intermediate intervals (e.g. 200-400 msec) Iin slow shows facilitation. This is revealed in calculations of the net charge transfer and current deficits and is also shown in the tail currents following repolarization. The deficit increases progressively with repetitive stimulation. With longer intervals (e.g. 800-1000 msec) defacilitation during repeated stimulation after the first two pulses is revealed in calculations of deficits, current trajectories and in the tail currents. 7. Although facilitation depends on duration of repolarization between pulses, increasing intermediate hyperpolarizations from the holding potential of -50 mV are usually ineffective in increasing Iin slow. Strong preceding hyperpolarization can even decrease the magnitude of Iin slow and prevent its facilitation with repetitive stimulation,whereas preceding depolarizing pulses can increase Iin slow without preventing its facilitation with repetitive stimulation. 8. The properties of Iin slow are contrasted with previously described membrane conductances and compared with properties attributed to Ca fluxes in other systems.


Control of the delayed outward potassium currents in bursting pace-maker neurones of the snail, Helix pomatia. The net outward current in bursting pace-maker neurones of the snail (Helix pomatia) during sustained and repeated voltage clamp pulses was studied. The properties of currents remaining in cobalt-Ringer or after TEA injection were compared with those in untreated cells. 2. With sustained voltage clamp depolarizations the net outward current first increases to a maximum at 150 msec and then declines to 60% or less of its peak intensity. This depression, which is greater during repetition of short pulses (e.g. 100 msec pulses at 0-5 sec intervals), represents a true decrease in the outward flow of K (designated IK) and is not due to a decreased driving force resulting from extracellular K accumulation. The steady-state current-voltage (I-V) relationship for IK is N-shaped (Heyer & Lux, 1976). 3. A component of IK persists when Ca and Mg in the medium are replaced by Co (ICo-res). With voltage clamp depolarizations ICo-res increases rapidly to a maximum and then partially inactivates with voltage dependent time constants of hundredths or tenths of seconds. Repolarization removes the inactivation. Thus, repeated stimulation with short pulses does not increase the depression of ICo-res-ICo-res (e.g. measured during voltage steps from holding potentials of -50 to near 0 mV) is smaller in test pulses preceded by depolarization and larger in pulses preceded by hyperpolarization. The steady state I-V relationship is not N-shaped. ICo-res is blocked by intracellular injection of tetraethylammonium (TEA). 4. Repeated voltage clamp depolarization to near 0 mV with 100 msec pulses for neurones with large Ca currents in normal Ringer produces a long-term depression which is maximal with 300-400 msec repolarizations (to -50 mV) between pulses. This corresponds with stimulus parameters for the maximum Ca current (Heyer & Lux, 1976). Intracellular injection of Ca2+ (also Ba2+ and Co2+) likewise reduces the total net outward current and especially the delayed outward current under voltage clamp. 5. The component of IK which is removed by Co is identified as Ca dependent and designated IK(Ca). With single voltage clamp pulses IK(Ca) follows the approximate time course and voltage dependence of the slow inward Ca current (Iin slow; Heyer & Lux, 1976). Several lines of evidence suggest that Ca ions moving through the membrane activate IK(Ca). 6. Part of IK cannot be blocked by intracellular TEA injection. In different neurones the magnitude of the IK component resistant to TEA (ITEA-res) is approximately proportional to the relative magnitudes of Iin slow.ITEA-res does not inactivate with sustained depolarization and shows pronounced long-term depression with repetitive stimulation at intermediate intervals and an increased outward current at the onset of the second and subsequent pulses following short repolarizations. The steady-state I-V relationship is N-shaped. ITEA-res is abolished by extracellular Co. 7. A net inward current with low depolarizations can be measured after TEA injection...


Atrial receptors in the cat.

Atrial receptors in the cat. Action potentials were recorded from slips of the cervical vagi in anaesthetized cats. Single functional units with atrial patterns of discharge (type A, B and Intermediate) were first obtained and then attempts were made to alter (i.e. convert) their patterns of discharge. Finally the points of origin of their action potentials were located. The investigations were done in five stages. 2. In the first series, thirty unselected units were investigated in thirty cats. Twenty-five of these were located in the endocardium of vein-atrial system and consisted of two type A, fifteen type B and eight Intermediate type units. The remaining five units were located elsewhere in the chest Conversion of the pattern of discharge was achieved in sixteen of the twenty-five atrial units. Both atrial type A units were converted. 3. In the second series, eight type A units were selectively studied in twelve cats. Five were located in the atrial endocardium and all were converted. Of the other three units which were located at other sites in the chest, one could not be converted. 4. In the third series, four type A units which could not be converted were selectively studied in twenty cats. All were located outside the atria. 5. In the fourth series, three type B units which could not be converted were selectively studied in six cats. These units were located in the pulmonary veins and in the lateral walls of the atria. 6. In the fifth series, fifty-five units were investigated in three anaesthetized spontaneously breathing cats. The proportion of the types of units were similar to that obtained in the artificially respired cats (first series). 7. The present study has shown that atrial receptors with a type A pattern of discharge are relatively rare in the cat and that conversion of the patterns of discharge is a common phenomenon. Evidence is presented which suggests that there is one basic type of atrial receptor whose pattern of discharge is determined by their precise location in the vein-atrial system.


Permeability of individual human erythrocytes to thiourea. The osmotic swelling to haemolysis of individual red blood cells by isosmotic thiourea has been studied using microcine photography. 2. Crenation occurs immediately upon addition of isosmotic thiourea. The cell becomes a crenated sphere without volume decrease. 3. Subsequently, the cell volume increases linearly with time with maximum swelling occurring at about 102 sec which is 81% of the total haemolysis time. 4. At maximum swelling, the cell volume is 92% greater than the initial cell volume. This volume increase is about double that measured with other permeating substances. 5. The much larger maximum volume implies that thiourea increases the area of the cell membrane. This increase varies from 0 to 75% for individual cells, with a mean of 22%. 6. Membrane expansion varies inversely as the initial cell membrane area and cell volume (r=0-790). 7. Using the increased surface area, increased maximum volume and the swelling time, the mean permeability is calculated to be 5-52 X 10(-7) cm/sec (S.D. of mean=+/-1-19 X 10(-7) cm/sec). The distribution of permeabilities represents a normal distribution. 8. The pre-lytic potassium loss ranged from 0 to 36% with a mean value of 16-5%. This is consistent with values reported in the literature for slow haemolysis. As with other permeants the distribution is skewed towards lower values. 9. Membrane permeability of individual cells varies with the amount of membrane expansion observed. Coefficient of correlation between permeability and expansion index is 0-674. 10. There is no correlation between permeability and the reciprocal of the haemolysis time (r=-0-035). The correlation between permeability and the reciprocal of the swelling time is also poor (r=0-303), probably owing to the variability in membrane expansion by thiourea in individual cells. 11. As has been shown previously for faster permeants, the permeability coefficient cannot be calculated from the haemolysis time. Because thiourea alters the membrane area and the haemolytic volume, the coefficient cannot be calculated from the swelling time unless the changes in the membrane area are also taken into account.


The responses to nerve stimulation of the salivary gland of Nauphoeta cinerea Olivier. A study has been made with intracellular electrodes of the responses of acini of the salivary gland of Nauphoeta cinerea Olivier to salivary duct nerve stimulation. The gland is a paired structure and offers the possibility of investigating the interaction between ipsi- and contralateral nerve stimulation. 2. The characteristics of the responses are as previously described for field stimulation (House, 1973). The latency is of the order of 1 sec and almost independent of the amplitude of the response which may attain a hyperpolarization of about 80 mV. The depolarization which sometimes follows can be disassociated from the preceding hyperpolarization and is presumably an independent response. 3. The stimulus-response relationship shows that acini are multiply innervated. Those close to the mid line recieve axons from both ipsi- and contralateral salivary duct nerves. The response to a test stimulus T can be augmented by an immediately preceding conditioning stimulus C, the joint response being greater than the sum of the separate responses. This effect occurs even when C and T are delivered to different nerves. For longer intervals between C and T, the response to T is depressed.


Intracellular membrane junctions during the exocytosis of insulin. In the process of insulin release by exocytosis, a fusion between the membranes of secretory vesicles and the plasma membrane occurs which is followed by the rupture of these membranes and the formation of an exocytotic stoma. As revealed by freeze-fracturing, the membrane structure is altered in the region of membrane interaction. An accumulation of membrane-associated particles can be observed in membranes of secretory vesicles contacting the plasma membrane. At the exocytotic stoma the boundary between granule limiting membrane and plasma membrane is occasionally outlined by a ring-like aggregation of membrane-associated particles. The effects of hypertonic solutions on tissue structure indicate that the membrane junctions during exocytosis are permeable to ions and small molecules, forming a communication between the interior of the secretory vesicle and the extracellular space.


Destruction of the sodium conductance inactivation by a specific protease in perfused nerve fibres from Loligo. Intracellular perfusion of giant axons from Loligo forbesi with a crude protein extract of Pronase dissolved in a KF solution suppresses the process of fast inactivation of the Na conductance (the h-process in the Hodgkin-Huxley terminology). 2. The results with protease inhibitors indicate that the most substrate specific endopeptidase present in pronase, alkaline proteinase b, destroys the h-process. 3. After destruction of the inactivation the conductance rise upon depolarization followed cube law kinetics. Values of the time constant taum before and after destruction of the h-process were very similar. 4. After destruction of the inactivation process the following properties were tested: cation selectivity, instantaneous conductance and internal receptor sites for tetrodotoxin (TTX) and tetraethylammonium (TEA). No detectable changes in selectivity or instantaneous conductance were observed. No internal receptors for TTX affecting the Na conductance were found but a TEA receptor is exposed by the protein hydrolysis. 5. TEA derivatives (triethylammonium, TEA-, with an aliphatic chain, Cn) induce a partial block of the steady-state sodium current and induce a time-dependent blockage of the conductance. 6. The first effect of TEA-Cn could be described in terms of a unimolecular reaction with the following equilibrium constants: 50, 2-5, 1-0, 0-4 and 0-025 mM for TEA-C2, TEA-C4, TEA-C5, TEA-C7 and TEA-C9 respectively. 7. From the dependence of the equilibrium dissociation constant on the length of the alkyl chain we estimated the free-energy change in 560 cal/mole of CH2. The gain in free energy per CH2 group transferred from aqueous medium to the interior of a non-polar medium is 1000 cal. 8. Although with the data at hand it is impossible to propose the amino-acid sequence of the site cleaved by alkaline proteinase b, we propose that an important functional component is arginine (or lysine).


The initial psychotherapy interview: a content analysis of the verbal responses of novice and experienced therapists. This study tested and confirmed the clinical impressions that (a) the novice psychotherapist may focus so much upon the exact words and nonverbal behavior patterns of his client (the process of making "concrete" statements) that he may lose sight of the larger picture that his client may be revealing at any given moment during the interview; (b) the experienced psychotherapist, on the other hand, seems to be responding to the words of the patient at a level of abstraction that attempts to integrate and understand the messages that the patient is trying to convey about himself; and (c) this latter process is reflected in the making of relatively more "abstract" comments than is true of the novice. Ss were 24 first-year psychiatric residents and 19 staff psychologists and psychiatrists at a veterans hospital and a medical school. The learning theory implications of these findings is discussed.


Relationship between auditory-visual integration, reading readiness, and conceptual tempo. A modified downward extension of Birch and Belmont's auditory-visual integration test was correlated with the Metropolitan Readiness Test for 82 middle class kindergarten children. From this same sample the test performances of an equal numer (n = 11) of impulsive females, impulsive males, reflective females, and reflective males were compared with use of a 2 X 2 analysis of variance. An analysis of convariance was employed to further examine test performance. Metropolitan scores were equated for Verbal IQ; for auditory-visual integration, test response time and Verbal IQ were individually held constant. Auditory-visual integration variance accounted for 29% of Metropolitan variance. Reflectives performed significantly better than impulsives on the auditory-visual integration test with or without response time or WPPSI Verbal IQ held constant; they performed significantly better than impulsives on the Metropolitan, but this did not maintain when scores were equated for WPPSI Verbal IQ.


Word imagery modalities and learning in the deaf and hearing. The study explored the modality specific hypothesis of imagery concreteness. Twenty-four male and female deaf and hearing adolescents learned lists of paired associates that were either high visual and low auditory imagery words or the obverse. It was predicted that the deaf group would perform as well as the hearing group with pairs of high visual imagery, but worse with materials of high auditory imagery. The results failed to demonstrate the expected interaction. However, indirect support for the hypothesis was provided by a third order interaction trend analysis which suggested that the deaf group experienced difficulty in learning the high auditory imagery word pairs.


Methodological problems in the study of fears. The purpose of this paper is to elucidate methodological problems in the study of fears and to make suggestions that will facilitate future research. The most basic problem begins with a definition of "fear". Other considerations include methods of assessment, classification, and the instruments used.


The effects of perceived status and linguistic diversity upon judgment of speaker attributes and message effectiveness. It has been shown previosly that high linguistic diversity positively affects listeners' judgments of speaker attributes and message effectiveness. Diversity refers to the degree of lexical and syntactic redundancy in a message. In the present study it was predicted that listeners' initial perceptions of a speaker's status would influence their judgments of high- and low-diversity messages. Ss were 46 male and female undergraduates at The University of Iowa. Three competing predictions were offered, and the results supported a status-attribution explanation. A high-status speaker was rated especially negatively when he delivered a low-diversity message. High- and low-diversity messages did not differ in their evaluative consequences for a low-status speaker; in this case both message types produced ratings that fell between the relatively positive or negative ratings given to the high-status speaker.


Perceptions of color preferences-a clue to marital prediction? In a study of marital adjustment prediction (N = 75 couples), each spouse was asked to indicate a color preference for nine common household articles and predict which color the spouse would choose. A discrepancy score between perceived and actual choices was calculated and compared with scores on the Nye-MacDougall Martial Adjustment Scale. The correlation coefficient between the discrepancy score and ego's marital adjustment was -.27 for the sample as a whole, -.33 for husbands, and -.21 for wives. The correlation between the discrepancy score and mate's marital adjustment was -.17 for the whole sample, -.10 for husbands, and -.23 for wives.


Performance under health-engendering and health-depressing conditions. Undergraduate psychology majors (four males, four females) were trained to role play health-engendering (HE) and health-depressing (HD) behaviors. Introductory psychology students (N = 48) were tested under different role playing conditions. Measures were taken before and after the role playing by an investigator who played a neutral role. A balanced two-way design was used. Four groups (N = 12 each) were thus formed: males under HE conditions, males under HD conditions, females under HE conditions, and females under HD conditions. Results indicated that the Ss did discriminate the roles when asked to rate a variety of characteristics. On two measures of learning (CVC lists and abbreviated digit span) the role of E had no effect; the role playing did not interfere with performance. It was found that the self figure in the human figure drawing was significantly smaller under HD conditions. This finding lends support to the body image hypothesis.


A scale for the measurement of attitudes to mental illness. An instrument consisting of 40 semantic differential scales was administered to 125 female student nurses who were instructed to rate the concepts "normal person," "typical mental case," and "mad man." The mean scores on the three ratings were significantly different (p less than .001). Coefficient alpha ranged from .90 to .93, and average item-correlation (total minus item) from .41 to .47. These results justify further use of the instrument.


Incidental serial reaction time: normal and schizophrenic response to the onset and cessation of auditory signals. This study tested the hypothesis that incidental serial reaction time (ISRT) latencies would be slower and more variable for schizophrenic than for normal Ss. It was predicted that the response of both groups to a manipulated stimulus dynamism would be proportionate, however,despite a difference in level of performance characterizing each sample. S responded to a series of 1000 Hz audiometric tones, signaling tone onset by pressure on a hand-switch, and offset by release. Thirty Ss without history of psychiatric disorder (16M, 14F) and 30 chronic schizophrenic patients (15M, 15F) were examined. All patients were drug-free and bore diagnoses of long standing. Signal tone length (1-3 sec) and interstimulus interval (1.5-15 sec) were varied randomly. Intensity levels were determined, in part, by reference to the individual threshold (T l, T j5 db) and partly by prior selection of fixed values to be used with all Ss (10 and 40 db). Mean ISRT response was significantly slowed for the schizophrenic group, and these latencies were markedly more variable. Increased signal intensity reduced the latency of ISRT, significantly, in each group. The stimulus dynamism induced change in ISRT was altogether similar for both groups, over a range of 15-65 db. No evidence for a diminished vigilance from the beginning to the end of the experimental sitting was found, for either sample.


A comparison of the WISC and WISC-R in a juvenile delinquent population. WISC and WISC-R subtest and IQ scores were compared in two samples of juveniles referred to a large metropolitan juvenile probation department (Ns = 180 and 185, respectively). The samples were equated for age, sex, race, and grade level. Significant differences were found on six of the 10 subtests. There were also significant differences between WISC and WISC-R scores on the Verbal, Performance, and Full Scale scores. In each case the WISC-R score was lower than the WISC score with the exception of the Arithmetic subtest. We conclude from these data that juvenile delinquents score significantly lower on the WISC-R than on the WISC. Psychologists using the WISC-R where the WISC had been previously used should educate their referral sources and other users of scores from the WISC-R to the differences in the test scores between the WISC and WISC-R.


The effect of the Yom Kippur war on anxiety level in Israeli children. Peacetime and wartime anxiety levels in fifth and sixth grade Israeli boys and girls (N = 85) were compared as a function of sex, socioeconomic status, degree of war related stress, and self-concept. The Sarason General Anxiety Scale and the Tennessee Self-Concept Scale had been administered to the children in May, 1973. The anxiety scale was readministered along with a war stress questionnaire during the Yom Kippur War in December, 1973. The general anxiety level of the children nearly doubled, with the children who reported the lowest peacetime anxiety levels reporting the highest wartime levels. Contrary to expectation, the rise in anxiety level was not related to personal war stress or to self-concept.


Children's self-evaluation of performance as a function of sex, age, feedback, and sex-typed task label. Children in grades 3 and 5 (N = 160) performed a task which was labeled either sex-appropriate or sex-inappropriate. Following the task, prearranged feedback (success or failure) was provided, and the children evaluated the importance of ability, effort, task difficulty, and luck in determining their performance. Girls attributed failure to lack of ability more than did boys. Further, girls but not boys attributed failure to poor ability more than they attributed success to good ability. Successful boys emphasized ability more than luck, whereas successful girls did not. Sex-typed labeling of the task did not influence casual attributions, performance, or the attractiveness of the task to the child. Third and fifth graders displayed similar patterns of causal attribution.


The stability of four kinds of perceptual erros on the Bender-Gestalt. The test-retest reliability of the Bender-Gestalt Test was investigated for 157 second graders from two middle-class schools. The test-retest interval ranged from 11 days through 15 days. Testing was conducted in accordance with the Koppitz procedure, but errors of distortion, rotation, integration, and preservation were determined separately. The total time required to reproduce the designs were also recorded. The reliability estimate for the Koppitz score was generally satisfactory, but the estimates obtained for the four separate error categories and total working time were substantially smaller.


Personality discriminants of cognitive perception abilities. Discriminant analyses, using California Psychological Inventory scores, age, and Miller Analogies Test scores, were run on groups of graduate students in counselor training who were high or low on perceptual-cognitive tasks. Twenty male and 23 female Ss watched videotaped sessions in which each of two male and two female expressors talked for three minutes about each of three prescribed subject areas. Perceiver Ss then reacted to a semantic differential as they thought the expressors had previously reacted. Absolute difference scores were established for each S in each of three cognitive dimensions for each expressor sex, and a summary score was also established. Analyses were run on each of these seven scores. Implications for further research and for potential use of the phenomenon were discussed.


A note on the relationship of internality-externality, self-acceptance, and self-ideal discrepancies. To correct deficiencies in an earlier study testing the hypotheses that externals, compared to internals, exhibit a larger self-ideal discrepancy, lower self-concept, and lower self-acceptance, 55 male and female art and theatre undergraduate majors were administered the Adult Nowicki-Strickland Internal-External Scale and the Index of Adjustment and Value. Findings by analysis of variance indicated support for all hypotheses.


Effects of extroversion and neuroticism on learning and memory: a test of Eysenck's theory of individual differences in arousal. Forty Ohio University female undergraduates were classified as stable extroverts, neurotic extroverts, stable introverts, and neurotic introverts, as measured by the Eysenck Personality Inventory. Subjects were asked to learn four paired-associate lists-two forms of both simple and difficult lists. The dependent variables were errors in the learning of the lists to criterion and recall scores at short-term (15 second) and long-term (15 minute) recall intervals. The hypothesized interactions were not significant. Explanations for the negative findings involved the methodology and the questionable applicability of Eysenck's biologically based personality dimensions for defining individual differences in learning and recall.


Empirical validation of diagnostic similarities from a structural perspective. In an effort to establish definitive patterns of patient variables for the diagnostic categories used by psychiatry, this study investigated the similarity between diagnostic classes as perceived by psychiatrists when evaluating patients from their own caseloads. A grid method was used to evaluate the diagnostic process. Thirteen psychiatrists rated their own patients on the constructs generated from their own personal dimensions. An overall analysis of the data demonstrated that patients within a diagnostic category were seen as more similar to one another than were patients from different diagnostic categories. Similarities between diagnostic classes showed that neurotic/situational maladjustment, personality disorder/alcoholic, and psychotic/alcoholic were the most similar pairs of unlike diagnoses. Examination of the process of diagnosis showed the functional similarity between some diagnostic classes. Specific areas of diagnostic similarity were present in a system that produced overall diagnostic clarity. Implications for the use of the grid method in psychiatric training were discussed.


Dynamics of contraceptive failures.

Dynamics of contraceptive failures. The purpose of this study was to explore the vicissitudes of contraceptive efforts and practice, and human behavior contributing to contraceptive failure. A consecutive sample of 481 women, who visited various gynecological out-patient clinics of a New York City municipal hospital between August 1974 and August 1975, served as the study population. There were 181 women with planned pregnancies and 300 women with unplanned pregnancies. The data were gathered in personal interviews. By comparison of both groups it was discovered that the women with unplanned pregnancies, because of their lower frustration tolerance level, had been led by successive difficulties related to contraceptive efforts and practice to episodic, faulty, or nonuse of technically effective contraceptive methods. Thereafter, psychological processes and mechanisms gave rise to a false sense of security, which virtually prevented them from resuming contraceptive practice. These psychological processes and mechanisms also govern other spheres of human behavior and merit systematic investigation.


Psychological differentiation in Nigerian children. The human figure drawings of 646 male and female Nigerian primary school children were analyzed with the use of Witkin's Articulation of Body Concept (ABC) scale. There was a significant association between age and ABC scores for the Ss as a group. The correlation between age and ABC scores was significant with male Ss and almost so with female Ss. These findings are on the whole consistent with the results of previous research conducted in different sociocultural settings.


Sex effects in leader behavior self-descriptions and job satisfaction. This study investigated possible sex differences in leadership among supervisory employees (N = 72) of a large psychiatric hospital by comparing male and female self-descriptions of their own leader behaviors, as well as their satisfaction with various aspects of their jobs. Female leaders described themselves as performing more consideration and tolerance of uncertainty leader behaviors and as being more satisfied with co-workers than male leaders. The possibility, suggested by sex role stereotypes, that self-perceptions of consideration behavior for females and initiating structure for males are related to job satisfaction was not affirmed by the findings. Although some differences were found, the results generally support indications from studies based on subordinate descriptions that there actually may be few job-related differences between male and female leaders.


Sibsize, family environment, cognitive performance, and affective characteristics. The study examined to what extent relationships between sibsize and the cognitive and affective chaarcteristics of children were mediated by family environments. The Alice Heim nonverbal intelligence test (AH4), the Watts Vernon English test, and the Vernon graded mathematics test were used to assess the cognitive performance of 15-year-old children (383 boys and 396 girls). The Ss formed part of a longitudinal national study of English school children. Also schedules were administered to measure children's educational and occupational aspirations, self-concepts, and attitudes toward school. From parental interviews a family environment index consisting of both distal and proximal measures was constructed. The Jackknife technique was used in the analysis to adjust significance levels. Regression surface analysis indicated that at each environment level, sibsize was related only to the English achievement of girls and boys and to the aspirations of girls. However, the shapes of the surfaces suggest that if parents create differential learning environments for different siblings then the behaviors of the siblings are likely to vary, which provides tentative support for the confluence model of sibsize influences on the behaviors of children.


Short-term retention in retarded adolescents as a function of load, delay, and interpolated activity. The present study investigated certain variables influencing the short-term retention of retarded adolescents. Forty trainable and 40 educable retarded adolescents were shown slides containing arrays of 2, 3, 4, or 5 chromatic pictures to be recalled after varying periods (0, 18, 36, and 140 sec) of filled or unfilled activity. Results indicated that recall in the unfilled condition remained relatively stable over time, while in the filled condition recall was deleteriously affected by a distracter task (p less than .01). No significant retention slope differences were observed between the two IQ groups. As is typically found with nonretarded adults, the curve of forgetting for the retarded individuals described a negatively accelerated function. With increasing proactive interference there were increasing decrements in short-term recall, with neither IQ group differing from the other. It was suggested that both decay and interference contribute to the short-term forgetting of retarded people.


Effects of evaluating task competence on the self-concept of children from different socioeconomic status levels. Previous studies reported low SES children with higher self-concepts than high SES children; this experimental study probes explanatory factors. One hundred sixty second grade boys and girls were measured on self-concept following a design-copying task on which they received either a positive or a negative evaluation, either through the E's evaluative statements or through presentation of standards for the task. Direction of evaluation was reflected in children's ratings of their own work. There was an interaction between direction of evaluation and SES as they affected self-concept, with negative evaluation leading to enhanced self-concept scores of low SES children.


MMPI characteristics of good and poor social problem-solvers among psychiatric patients. In an attempt to delineate more precisely the relationship between problem-solving cognition in the social sphere and psychopathology, male (N = 83) and female (N = 107) psychiatric patients were divided into groups of good and poor problem-solvers on the Means-Ends Problem-Solving (MEPS) Procedure and contrasted on MMPI scales and indices of psychopathology. Poor problem-solvers among males, but not among females, were found to be (a) more clearly schizophrenic and socially inadequate, with significantly higher scores on the Pd, Sc, and Si scales; (b) more clearly psychotic on the Goldberg Index; and (c) more likely to have elevated F scale raw scores. The present findings explicate those of earlier studies in suggesting that male patients higher in social problem-solving ability are not only likely to be more socially competent, but also are more likely to be less severely impaired in terms of psychopathology. A possible explanation for the sex difference is that problem-solving cognition and psychopathology are not so directly related in females as in males.


An examination of the relationship between personality traits and motivational dynamics. The relationship between personality traits and motivational dynamics was investigated with focus on issues concerning their independence. Matched 16 Personality Factor (PF) and Motivational Analysis Test (MAT) questionnaires were obtained on 691 male and female undergraduates and Air Force personnel, and the scales were factor analyzed. Thirteen factors were indicated of which five were purely personality and four motivational, thus pointing to the independence of the two domains.


Performance of student nurses on the Edwards Personal Preference Schedule. One hundred sixty-seven female nursing students in a baccalaureate program were administered the Edwards Personal Preference Schedule. Comparisons were made with the original norms for college women and with recently published norms for a group of urban college women, as well as with data for a group of nursing students collected at the time of the appearance of the original norms. While nursing students reflected some of the significant changes occurring among college women between 1959 and 1973, they continued to maintain a profile of needs consistent with the traditional view of those in their profession.


Relevant stimuli and auditory evoked potentials. Four cats, classically conditioned to a flashing light paired with food reinforcement, were tested for amplitude changes of click-evoked potentials during increasing hours of deprivation. Signal averaged evoked potentials from the auditory cortex, cochlear nucleus, and round window electrodes showed no significant changes in amplitude, but significant changes were found in the variance as food deprivation increased. Such changes are more consistent with expected changes in the CNS than the amplitude changes of the auditory cortex found by Saunders and Chabora.


[T.D.F. (time-dose-fractioned irradiation) and tolerance to low flow and low fractioned irradiation (author's transl)]. 1. The factor (T.D.F.) defined by ORTON and ELLIS for regularly distributed discontinuous irrdiation may be dissociated from Ellis' equation. The essential fact is that, in principle, the T.D.F. is given as 100 for all techniques which are associated with full tolerance or, if desired, exact saturation of the normal supporting tissue. 2. From this standpoint, all techniques in which T.D.F. = 100 have the same effectiveness as the N.S.D., i.e. 1,800 Rads given at a flow of approximately 10 Rads per minute. A TD.F. greater or less than 100 should be considered as evaluating the effective dose as a percentage of the N.S.D. The total dose administered effectively as a percentage of N.S.D., Dt/18 represents by contrast the actual dose. 3. With discontinuous treatment of 50 or 100 Rads/minute, the ratio effective dose over actual dose = T.D.F. 18/Dt represents the coefficient of reduction in effectiveness due to fractioning. Crf (the T.D.F. of which is given in the tables of Orton and Ellis). In the case of continuous uninterrupted treatment, the coefficient of reduction of effectiveness by protraction Crp is calculated using Orton's equation. With treatment given on an interrupted basis (split) the reduction in effectiveness Crs is calculated on the basis of the appendix ratio of Orton and Ellis. 4. In low flow rate, low fractioned treatment, in interrupted sections, the overall coefficient of reduction of effectiveness equals the product of the three mentioned above: Crg = Crf-Crp-Crs. 5. Dissociation of the T.D.F. factors from Ellis' equation makes it possible to generalise its principle and to extend it to all normal tissue (kidney, lung, intestine, marrow), the T.D.F. of which represents that state in which radiolesions are maximally compatible with reversibility, in the immediate or in the shortest possible time. It would be theoretically possible, using a suitable experimental technique, to develop, for each of these particularly senstive organs, tables analogous to those provided by ORTON and ELLIS for supporting tissue in conditions which seem acceptable to many.


Indications for combination of irradiation and surgery. 1) The concept "either irradiation or surgery" for all clinical situations should be eliminated. In many clinical situations, one must think of the combined treatment both for the primary lesion and the regional metastases. Conservatism in both disciplines is to be preferred. 2) If irradiation has no place as the sole treatment for a disease, for example soft tissue sarcomas or parotid tumors, it does not mean that it has no place in the management of the disease. 3) The sequence of the modalities of treatment depends upon the structures involved and the extent of the surgical procedure. If one has to choose between a relatively low dose preoperative irradiation, like 3,000 to 4,000 rads or 5,000 to 6,000 rads postoperatively, the theoretical advantages of preoperative irradiation are outweighed by the proven effectiveness of postoperative irradiation in controlling the locoregional disease.


[Quantitative study of the regression of mammary cancers after irradiation (author's transl)]. Quantitative study of the regression 50 mammary cancers after radiotherapy showed that it took an exponential course. The graphic impression was confirmed by statistical study of the linearity of the regression. A time for half-disappearance can therefore be useful in order to distinguish the regression of mammary cancer after irradiation. Its mean value for 47 of our cases was 17.8 days. The significance of this parameter is certainly complex; it is possible that a prognostic value can be attributed to it.


[The problem of sterility in men and women after wide area sub-diaphragmatic irradiation (author's transl)]. Sub-diaphragmatic irradiation in an upside down Y pattern for Hodgkin's disease results in sterility in the women. Protection consists of irradiating the lumbar chain only when possible or by displacement of the ovary before irradiation, and laterally for preference. Although subsequent pregnancy is then possible, the genetic risk remains. In the male, Y irradiation results in prolonged virtually complete azoospermia. Associated chemotherapy also causes definitive sterility in the male. Collection for a sperm bank before treatment is advised.


[Practical use of lithium borate in thermoluminescent dosimetry (author's transl)]. The authors recall the functional principles of thermoluminescent dosimeters: heating, apparatus for measuring the emitted light, circulation of nitrogen, reference source. They take this opportunity to stress the essential role played by the circulation of nitrogen over the dosimeters which equilibrates the temperature of the photo multiplier, reduces the emission of unwanted light, prevents the combustion of dust or other possible impurities and finally improves the reproductibility of the measurements even for high dosod for finding the optimum working conditions for the heating apparatus of the planchette in the most simple T.L.D. readers and in those where the heating apparatus of the planchette has a pre-heating phase. They then study the dosimetric properties of lithium borate incorporated in thin teflon discs (type DLB. 0.13 and 0.4). This shows itself to be very interesting for certain uses because it is a solid dosimeter which does not require annealing between two measurements. The reproductibility of the measurements obtained with this material, the stability of its response relative to the delay between radiation and reading (fading), its response relative to the absorbed dose plus the nature and the energy of the rays, are presented with the usual reservations made for this type of dosimetry. The authors conclude by citing a few applications where they have been able to achieve a satisfactory result with the aid of lithium borate.


[Dosimetry of high energy electron beams from a linear accelerator (author's transl)]. The dosimetric characteristics of the electron beams from the Sagittaire (C.G.R. MeV) linear accelerator are presented. The variations in dose output with the distance from the source are indicated for the usual treatment distances. The measurements carried out demonstrating the deviations from the inverse square law for distances. The graphs for the variation in dose output in terms of the opening of the collimator are given for square and rectangular openings. The measurements demonstrate the preponderant influence of the short side 1 of the rectangular field of the relative variation in dose output. The variations in the graphs of the deep yield in terms of beam energy, distance from the source and field dimension were studied. For the different energies, the influence of the distance from the collimator and the dimension of the field on the dose at entry and on the depth of the maximum was shown. Measurements of the deep yields were carried out in the case of rectangular fields. In each case, the side of the equivalent square field corresponding to the same deep yield as a 1 X L rectangular field was determined; a comparison was carried out with the equivalent square field defined for colbat radiation.


[Development and use of an automatic conversational system for the calculation of dose in teleradiotherapy (author's transl)]. The authors describe the equipment and methods of calculation used for a system of automatic conversational dosimetry with a mini-computer. They present the dialogue of the physician with the calculator and indicate the conditions they required of such a system: i.e. rapidity of response, simplicity of use, verification of data, precision, adaptability. Testing involved 800 dosimetric cases including 300 cases of routine clinical dosimetry.


[Technical modification of moulds construction for gynecological curietherapy (author's transl)]. The authors describe a new, faster and less-laborious method of moulds construction for gynecological curietherapy.


[Adaptation of an A.G.S. endo-uterine catheter for hysterographic examination during radium therapy (author's transl)]. The authors propose an endo-uterine catheter which will permit a hysterographic examination to be made during utero-vaginal radium therapy, thus making it possible to check: --that the catheter has advancec correctly after insertion; --that the uterine cavity intact: --that the catheter is in the correct place; --its retention during treatment. By using radio-opaque rings and small balloons in the hysterographic examination, it is possible to locate: --the external orifice of the cervix; --the urethral meatus; --the anterior wall of the rectum and the posterior wall of the bladder. In this way, the target volume is loated  with precision, and the length, position and activity of the various radio-active sources can be adapted accordingly.


The production, morphology, karyotypes and transport of spermatozoa from tertiary trisomic mice and the consequences for egg fertilization. Tertiary trisomic males, carrying the small translocation chromosome from the T(1;13)7OH reciprocal mouse translocation as the extra chromosome, are oligospermic. Uterine and oviductal sperm counts were congruent to 10% of normal. Of the uterine spermatozoa, 77-2% were morphologically abnormal compared with 24-6% in the oviduct. Oligospermy in the tertiary trisomic males leads to delayed fertilization; 34-8% of the 109 eggs scored between 5-5--9-5 hr after mating were fertilized compared with 52-1% (n=343) at Day 2. Of the 179 morulae/blastocysts recovered at Day 4, 46-9% contained the small marker chromosome, which agrees with earlier cytological studies on secondary spermatocytes. These results indicate that euploid and aneuploid spermatozoa are formed in about equal numbers and there is no relationship between sperm morphology and karyotype.


Effects of alpha-chlorohydrin on the metabolism of testicular and epididymal spermatozoa of rams. Spermatozoa were collected from the rete testis and vas deferens of conscious rams. The endogenous oxygen uptake of the spermatozoa was unaffected by alpha-chlorohydrin added in vitro, although this compound abolished the stimulation of oxygen uptake caused by the addition of glycerol. The metabolism of [14C]glycerol by testicular and epididymal spermatozoa was markedly reduced by alpha-chlorohydrin, CO2 production and lactate accumulation being almost totally inhibited. These effects were dependent upon a period of preincubation of the spermatozoa with alpha-chlorohydrin alone, since the presence of glycerol protected the spermatozoa from its action. Longer exposure and a higher concentration of alpha-chlorohydrin were needed with testicular than with epididymal spermatozoa to achieve a maximal effect. The metabolism of [14C]glucose by both sperm types was also inhibited by alpha-chlorohyrin. Spermatozoa of the ram are therefore susceptible to the action of alpha-chlorohydrin throughout the epididymis, although more mature spermatozoa are more affected. It is suggested that alpha-chlorohydrin is converted to an intermediate which is the agent responsible for the inhibition of glycolysis in spermatozoa.


Histochemical studies of delta5-3beta-, 20lapha- and 20beta-hydroxysteroid dehydrogenases and possible progestagen production in hamster eggs. Hamster eggs at various developmental stages were studied histochemically fro the presence of delta5-3beta-hydroxysteroid dehydrogenase (HSD) (pregnenolone as the substrate and NAD as the cofactor), 20alpha-HSD (20alpha-hydroxypregn-4-en-3-one and NADP) and 20 beta-HSD (20beta-hydroxypregn-4-en-3-one and NAD). All three enzymes were absent from ovarian eggs but were demonstrated in unfertilized and fertilized eggs up to the blastocyst stage. The activities varied only slightly.


Cytochalasin B-induced triploidy in mouse oocytes fertilized in vitro. Mouse eggs and spermatozoa were treated in various ways with 5 or 10 mug cytochalasin B/ml. The fertilization rate in vitro was reduced by treatment with the drug but 80-90% of the eggs fertilized were triploid. Many of the experimental eggs were penetrated by one or more spermatozoa but remained unfertilized (75% compared with 9% in control eggs). It is suggested that cytochalasin B weakens the zona reaction and interferes with fusion of gametes but does not prevent the block to polyspermy.


A comparison of the ultrastructure of spray-frozen and freeze-etched or freeze-dried bull and boar spermatozoa with that after chemical fixation. The ultrastructure of bull and boar spermatozoa was investigated following different cryopreparation methods and chemical fixation. Spray-freezing was used for cryofixation in both freeze-etching and freeze-drying studies. Freeze-etching of boar spermatozoa revealed that the arrangement of the postnuclear striations differed from that in the bull. Freeze-drying gave excellent results for structural preservation, which were equal to those of chemical fixation. Some structural details not visible in chemically fixed cells were detected in freeze-dried and vacuum-embedded bull and boar spermatozoa, e.g. the arrangement of the lamellar nuclear contents, known from freeze-fractures, and a fine lamellar structure of the acrosomal contents. Cryofixation by spray-freezing combined with freeze-drying makes any contact of the cells with fixatives, buffer solutions and dehydration media unnecessary, and potentially provides all the advantages of ultrathin sectioning required for histochemical studies.


Changes in the concentrations of testosterone and androstenedione in the plasma and testis of the guinea-pig from birth to death. Testosterone and androstenedione concentrations in the plasma and testis of male guinea-pigs were estimated by gas chromatography at intervals (36 stages) from birth to death. Four main periods of androgenic activity were recognized. The neonatal period, from birth to Day 16, is characterized by a precocious but transient peak in plasma testosterone concentration at Days 2 and 3. The pubertal period from Days 16 to 90 can be subdivided into a prepubertal period starting on Day 16 and marked by a sudden linear increase in plasma and testicular testosterone concentration together with an increase in testicular and seminal vesicle weight, and a postpubertal period, from Day 50 (the time of hormonal puberty) to Day 90, characterized by high and stable androgen levels while testicular and genital tract development continues. Adulthood spans the period between Months 3-6 and Month 24; plasma and testicular concentrations of testosterone and androstenedione are stable but lower than those observed during puberty. The period of senescence occurs between Months 24 and 28 and is marked by a fall in testosterone secretion and involution of the seminiferous tubules and accessory sex glands.


Developmental patterns of enzymes in mouse testis. Study of the activities of hyaluronidase, lactate dehydrogenase isoenzyme-X and the dehydrogenases of sorbitol, alpha-glycerophosphate, glucose-6-phosphate, malate, glyceraldehyde-3-phosphate and isocitrate in the testes of mice of different ages showed that the changes were correlated with the stages of spermatogenic cell differentiation. The first 4 enzymes had activities which were low in newborn mice and high in adults; this pattern was reversed for the other enzymes.


Effects of superovulation on fetal development and hormone levels in the pregnant hamster. Treatment of hamsters with 30 i.u. PMSG induced ovulation of 46 ova/animal, 90% of which were fertilized. CL growth was normal. About 27 zygotes/animal implanted and at term (Day 16) the litter size of the PMSG-treated hamsters was 21 compared to the normal number of 10. Parturition occurred at the normal time. Average weight at birth was about 500 mg less for young of PMSG-treated mothers than for controls. Differences were found in the serum progesterone and oestradiol concentrations of the treated and control hamsters, but serum FSH and LH levels were similar.


The acute effect of oestrogen injection on plasma LH in freemartin heifers. The acute effects on plasma LH concentrations of an injection of oestradiol-17beta were studied in 7 non-cyclic heifers and 19 freemartins. One freemartin showed a normal LH surge due to the positive feedback effect of oestrogen on the hypothalamus. Of the other 18 freemartins, 4 showed positive increases in plasma LH and 6 were unclassified. There was no correlation between the degree of chimaerism and responsiveness to oestrogen. The results also showed that injected oestradiol suppressed the spontaneous fluctuations of plasma LH.


The inhibition of in-vitro ovulation from follicles of the teleost, Oryzias latipes, by cytochalasin B. Ovulation in vitro from isolated follicles of the teleost fish, Oryzias latipes (the madaka), is completely and reversibly inhibited by cytochalasin B. Ultrastructural examination of treated follicles shows no morphological changes in microfilament populations within the follicle, but shows an increasing number of small holes in the basal lamina between the epithelial (thecal) cells and the follicle cells with increasing duration of exposure. It is suggested that these correlate with the decreasing success of ovulation after drug removal after longer incubations with cytochalasin B.


A highly efficient method for washing mammalian spermatozoa. A simple method has been developed for washing spermatozoa: the cell suspension is layered over a solution containing Ficoll and, after centrifugation, the original suspending medium remains as an undiluted layer above the Ficoll solution while the spermatozoa form a loose pellet at the bottom. Removal of the supernatant layers is easily and completely accomplished by aspiration. When ram spermatozoa were washed by this method, as much as 99-6% of the original medium could be removed during a single washing cycle, while up to 98% of the cells were recovered. Mechanical damage to the cells was minimal and repeatability was high.


Changes in steroid hormones in plasma and myometrium and uterine activity in ewes during late pregnancy and parturition. In 7 ewes during late pregnancy, peripheral plasma concentrations of oestrogens were correlated with uterine activity (P less than 0-01; r=+0-47). In myometrial tissue, the concentration of progesterone was similar to that in plasma; it rose to a plateau from Days 115 to 130 of pregnancy and then fell, but was still detectable during parturition. Myometrial oestrogen concentration was much higher than in plasma; from a peak at Days 100-115 it decreased, but rose sharply just before parturition.


Relaxin immunoactivity in human plasma during a 24-hr period. Relaxin was secreted episodically in all 6 human subjects studied. A 24-hr rhythm was detected in the pooled data, with maximum secretion in the early-midmorning hours and a nadir in the early evening.


Gastrointestinal injuries.

Gastrointestinal injuries. Any wound that penetrates the abdomen may involve the gastrointestinal tract whether controlled for a specific operation of diagnostic procedure or uncontrolled when secondary to blunt or penetrating trauma. The first important consideration is the prevention of complications. The choice of incisions, the managment of the contaminated peritoneal cavity, intestinal fistulas and specific bowel injuries and the importan differences in the treatment of injuries to small intestine versus to large intestine and rectum be considered. Bowel viability must also be determined.


Chorioamnionitis.

Chorioamnionitis. Chorioamnionitis is an inflammatory reaction occurring in the fetal membranes of the placenta. It is usually associated with premature rupture of the membranes, whether spontaneous or artificial. Rupture of the fetal membranes sets off a time bomb that threatens both maternal and fetal welfare. The seriousness of this threat is dependent upon several variables: the length of gestation, economic status of the patient and the duration of the rupture. There is a controversy about the relative importance of these variables and about the proper degree of aggressiveness necessary to achieve optimum fetal salvage. When chorioamnionitis occurs, most obstetricians agree that the uterus should be evacuated by the most expeditious route. Usually oxytocic induction will accomplish delivery without difficulty, but should it fail to effect cervical ripening and dilatation within a reasonable time, cesarean section should be performed without further delay. If cesarean section is necessary in the presence of gross infection, hysterectomy is advocated by some.


Genitourinary tuberculosis simulating cervical carcinoma. A bulky, necrotic cervix with parametrial thickening often elicits an initial diagnostic impression of carcinoma of the cervix. A case is presented in which such a lesion proved to be tuberculosis of the cervix with combined genitourinary tuberculosis.


Studies on Parafilaria bovicola (Tubangui 1934). 1. Clinical observations and chemotherapy. A detailed examination on a group of oxen naturally infested with Parafilaria bovicola suggested a prepatent period varying from 238 to 250 days. In these animals 54% of all lesions bled only once, 22% a second time and 24% more than twice. Of all active lesions 42% occurred in the shoulder region and decreased from this area both cranially and caudally. The same tendency was noticeable on carcasses after slaughter. During the observation period May 1974 to February 1975 the number of positive animals increased, reaching peak values during September - October 1974, after which a decline was noticed. The filaricidal effects of nine compounds were tested. These were suramin (used in combination with diethylcarbamazine citrate), thiacetarsamide sodium, fenchlorphos, phosmet, mebendazole, fenbendazole, levamisole hydrochloride and trichlorphon.


Cestodosis in battery-housed laying hens. Cestodosis in battery-housed laying hens severely reduced egg production particularly at the time of peak production. Hens were able to consume large numbers of Musca domestica, the intermediate host of Choanotaenia infundibulum following the use of an aerosol insecticide to control flies. A considerable discharge of cestodes followed the use of "Lintex" in the feed resulting in a marked improvement in egg production. The use of an insect growth regulator in the feed showed promise in controlling the breeding of flies.


The influence of seasonal changes in the determination of selenium in liver of various animals by neutron activation analysis and high-resolution spectrometry. Selenium levels in the liver of animals living in the Umfolozi Game Reserve in Natal and in the Sabi Sand Nature Reserve in the Eastern Transvaal were studied by instrumental neutron activation analysis. The distribution of the selenium content was followed for about 16 months and attempts have been made to explain seasonal fluctuations of the selenium level.


Pulmonary hypertension in relationship to acidaemia after maximum forced exercise. A further preliminary report. Pulmonary hypertension was shown to occur in wild young zebra and wildebeest subject to forced exercise over 2 to 5 km distance. Measurements of pulmonary arterial pressure were made on a Devices recorder connected to a catheter passed via the jugular vein. Systemic pressure was recorded after puncture of the dorsal aorta. The electrocardiogram, PO2, PCO2 and pH were determined and enzyme levels such as CPK were estimated. Reduction of the pulmonary hypertension occurred after bicarbonate infusion.


Caseous lymphadenitis in sheep -- methods of infection. Depending on the route of infection, experimental exposure of 30 sheep to Corynebacterium pseudotuberculosis resulted in either mucopurulent vaginitis, prosthitis, conjunctivitis, rhinitis, or in subcutaneous abscessation. Caseous lymphadenitis, from which the organism could be recovered in 52 out of 56 instances, occurred in every instance with the exception of animals infected by the preputial route.


Laboratory and field control of clinical mastitis in dairy cows around Bulawayo. The organisms responsible for clinical mastitis in dairly herds around Bulawayo were identified and their antibiotic sensitivity was determined. Streptococci, staphylococci and coliforms were responsible for 37%, 28% and 29,5% of cases respectively. Antibiotic resistance increased over the 3 year period. The high incidence of coliform mastitis is discussed, as is the effect of dry cow therapy on peri-natal mastitis and the nature of the scheme of control. The laboratory is considered an essential adjunct to other control methods.


The incidence and sources of penicillin in milk supplied to the city of Johannesburg. The incidence of penicillin in bulk milk supplies to the city has varied from 1,2% to 2,6% over the past five years, and 3,2% of 366 pasteurised milk samples examined in 1975 were found to contain penicillin. Investigation of the sources revealed numerous instances of producers, milkers and veterinarians who had not acted responsibly in regard to the marketing of milk from treated cows. Details are provided. The legal and professional obligations of the veterinarian are emphasized. Reference is made to the dye marking registered intramammary formulations for farmer treatment of mastitis.


Attempted artificaial infection or impala, blue wildebeest, buffalo, kudu, giraffe and warthog with heartwater. Intravenous injection of Cowdria ruminantium infected blood produced no sings of disease in four impala, Aepyceros melampus; three blue wildebeest, Connochaetes taurinus; a buffalo, Syncerus caffer; a kudu, Tragelaphus strepsiceros; a giraffe. Giraffa camelopardalis and a warthog, Phacochoerus aethiopicus. a control sheep injected with the same blood reacted severely and showed typical lesions of heartwater at autopsy.


The yellow mongoose (Cynictis penicillata) as a latent focus of rabies in South Africa. The role of C. penicillata as a latent focus of rabies in South Africa is discussed. A description of the colony life, feeding and breeding habits and the relationship of the Yellow Mongoose to the Suricate Meerkat and Ground Squirrel is given. Observations on the epidemiology and symptomatology of rabies in the Yellow Mongoose are reported and various methods of control are suggested.


The incidence of epistaxis in racehorses in South Africa. In South Africa 2,41% of horses bleed in a race. If all raced until they were 7 years old probably another 2,12% would bleed. Many others bleed after the race or during exercise or at rest. The incidence of epistaxis is significantly greater in geldings than in females and uncastrated males (P less than 0,001). There is an age distribution of bleeding which is highest at 4 years and lowest at 2 years of age (P less than 0,001).


Toxoplasmosis as a public health hazard. Recent advances in the epidemiology and life cycle of toxoplasmosis are reviewed. Cats play a key role. Toxoplasma has a coccidian-type entero-epithelial cycle with oocyst prodlction in the feline host. An extra-intestinal cycle occurs in both feline and non-feline hosts. The worldwide distribution and the public health significance of toxoplasmosis as a zoonosis is discussed, with particular reference to available data regarding Southern Africa.


A practical synthesis of codeine from dihydrothebainone. The conversion of dihydrothebainone to codeine or thebaine has been achieved in high yield. Bromination and dehydrobromination constructs the 4,5-oxide bridge to give 1-bromo- and 1,7-dibromodihydrocodeinone which yield dihydrocodeinone practically quantitatively after catalytic debromination. Ketalization and acid-catalyzed elimination of methanol give excellent yields of delta6-dihydrothebaine to which is added methyl hypobromite using N-bromoacetamide in methanol. The action of potassium tert-butoxide in Me2SO on the resulting 7-bromodihydrocodeinone dimethyl ketal gives codeinone dimethyl ketal selectivity at 60 degrees while at 120 degrees thebaine is the exclusive product. Hydrolysis to codeinone and borohydride reduction give codeine in 70% overall yield. The bromo intermediates in the formation of the 4,5-oxide bridge have been examined. 1,5beta, 7alpha-Tribromodihydrothebainone has been identified as the main product in the tribromination of dihydrothebainone.


Conversion of Thebaine to Codeine.

Conversion of Thebaine to Codeine. An improved conversion of thebaine to codeine has been developed. Oxymercuration of thebaine with mercuric acetate in refluxing methanol, followed by hydrolysis of the intermediate 7-acetomercurineopinone dimethyl ketal with 3 N acetic acid, or, alternatively, reduction of the organomercury compound with sodium borohydride and mild acid hydrolysis of the resulting neopinone dimethyl ketal, gives neopinone in 95-100% yields. Either acid- or alkali-catalyzed isomerization to codeinone leads to the equilibrium mixture consisting of codeinone-neopinone, 3:1. Complete conversion to codeinone in 85-90% yield results from treatment of neopinone with anhydrous hydrogen chloride or hydrogen bromide in ether-methylene chloride, followed by elimination of hydrogen halide from the intermediate 8-halodihydrocodeinone. The known borohydride reduction of codeinone then gives codeine in 85% overall yield from thebaine.


Modification of the 5' position of purine nucleosides. 1. Synthesis and biological properties of alkyladenosine-5'-carboxylates. A series of esters of adenosine-5'-carboxylic acid has been prepared. Most of the compounds were nontoxic, causing prolonged increases in coronary sinus PO2 when administered to anesthetized dogs; the ethyl ester was most active. Nitrosation and oxidation of the ethyl ester 12 gave respectively inactive inosine ethyl ester 30 and the fairly active N1-oxide ethyl ester 29.


Inhibitors of tRNA methyltransferases. S-Adenosylsulfonium salts. Three new compounds have been synthesized and tested as in vitro inhibitors of normal and tumor tRNA methyltransferases. These compounds are 5'-methylethyl(5'adenosyl) sulfonium chloride (MEAS), 5'-methylpropyl-(5'adenosyl)sulfonium chloride (MPAS), and 5'-ethylpropyl(5'-adenosyl)sulfonium chloride (EPAS) They were prepared by reacting an alkyl iodide with the appropriate alkyladenosyl thioether. Inhibition assays revealed all three compounds to be inhibitors of normal and tumor tRNA methyltransferases. The propyl compounds were slightly better inhibitors of the tumor tRNA methyl transferases. MPAS, EPAS, and MEAS had KI's of 58.5, 61.7, and 24.5, respectively, for the normal tRNA methyltransferases and 15.3, 13.8, and 44.3, respectively, for the tumor tRNA methyltransferases.


(2-Piperidine)- and (2-pyrrolidine)ethanones and -ethanols as inhibitors of blood platelet aggregation. (E)-4-[4-(Methylthio)phenyl]-1-(2-piperidinyl)-3-buten-2-one hydrochloride (44, RMI 14 133A) was found to inhibit ADP-induced aggregation of blood platelets. It was selected from a large series of (2-piperidinyl)- and (2-pyrrolidinyl)ethanones synthesized by a modified Schopf reaction from enolate magnesium salts of beta-keto acids and 2,3,4,5-tetrahydropyridine trimer or 3,4-dihydro-2H-pyrrole trimer, respectively. Evaluation of the compounds was carried out in vitro on human blood platelets. Structure-activity relationships are discussed. 44 also inhibited platelet aggregation ex vivo in guinea pigs. Subacute toxicity evaluation in dogs and guinea pigs showed it to have an unfavorable therapeutic ratio. 1-[4'-Chloro(1,1'-biphenyl)-4-yl-a1-2-(2-piperdinyl)ethanone hydrochloride (18, RMI 12436A) was found to lower serum cholesterol levles in rats with concurrent accumulation of (3beta)-cholesta-5,7-dien-3-ol, suggesting inhibition of 7-dehydrocholesterol delta7-reductase.


Catechol O-methyltransferase. 9. Mechanism of inactivation by 6-hydroxydopamine. A series of methylated analogues of 6-hydroxydopamine (6-OHDA) has been synthesized and evaluated as irreversible inhibitors of catechol O-methyltransferase (COMT). These analogues have been prepared in an effort to elucidate the mechanism involved in the inactivation of this enzyme by 6-OHDA. The analogues prepared had methyl groups incorporated in the 2 and/or 5 positions of 6-OHDA so as to block nucleophilic attakc at these positions in the corresponding oxidation products [6-hydroxydopamine-p-quinone (6-OHDAQ), aminochromes I and II]. Such 2- and/or 5-methylated 6-OHDA analogues were found to be inhibitors of COMT with the inactivation apparently resulting from modification of an essential amino acid residue at the active site of the enzyme. The activity of these analogues as inhibitors of COMT argues against a mechanism involving a 1,4 Michael addition reaction by a protein nucleophile at the 2 or 5 positions on 6-OHDAQ or on the corresponding aminochromes. Instead, an alternative mechanism is proposed to explain these data, which involves attack of a protein nucleophile at the carbonyl group in the 6 position of 6-OHDAQ or at the imine functionality on aminochromes I and II. The results of the present experiments have provided insight into the mechanism involved in inactivation of COMT by 6-OHDA. In addition, this study has provided considerable insight into the chemical reactivity of the electrophilic species generated after oxidation of 6-OHDA.


Potential antitumor agents. 14. 4-Substituted 2-formylpyridine thiosemicarbazones. A series of 4-substituted 2-formylpyridine thiosemicarbazones has been synthesized which contain a tertiary N at the 4 position. These materials were obtained by reacting 4-nitro-2-picoline N-oxide, either directly or after conversion to the corresponding 4-chloro derivative, with a variety of secondary amines. Rearrangement of the 4-substituted 2-picoline N-oxides with Ac2O yielded respective methyl acetates, which upon acid hydrolysis, MnO2 oxidation, and reaction with thiosemicarbazide resulted in the desired compounds. An alternate procedure which consisted of reacting 4-chloro-2-formylpyridine ethylene acetal with various amines, followed by hydrolysis and reaction with thiosemicarbazide, was also employed. Introduction of an alkyl group at the 3 position of the pyridine ring of 4-morpholino-2-formylpyridine thiosemicarbazone was achieved by utilizing 2,3-dimethyl-4-nitropyridine N-oxide; this material was converted to the corresponding 4-chloro derivative which was then subjected to nucleophilic substitution. 4-Morpholino-2-formylpyridine thiosemicarbazone was the most active antineoplastic agent of this series in mice bearing Sarcoma 180 ascites cells and was significantly  superior to 5-hydroxy-2-formylpyridine thiosemicarbazone in this test system.


Synthesis and antilipidemic properties of cis-7-chloro-3a, 8b-dihydro-3a-methylfuro[3,4-b]benzofuran-3(1H)-one, a tricyclic clofibrate related lactone having a structural resemblance to mevalonolactone. The synthesis for the title lactone 2, designed to be an antagonist of the enzyme HMG-CoA reductase (E.C.1.1.1.34), is described. Lactone 2, its synthetic tricyclic hemiacetal precursor 4, and clofibrate were investigated for their antilipidemic activity in 7-day treated normal and in Triton WR-1339 induced hyperlipidemic male Sprague-Dawley rats. After 7-day drug administration to normal rats, lactone 2 was less effective than clofibrate in lowering HMG-CoA reductase activity and serum cholesterol; however, unlike clofibrate, lactone 2 did not increase liver weight or liver-body weight ratio or lower serum triglycerides. Since hemiacetal 4 selectively influenced triglycerides in normal animals, lactone 2 and hemiacetal 4 appear to have differential hypolipidemic effects. In the Triton hyperlipidemic model 2 and 4 lowered elevated triglycerides; only 4 significantly reduced elevated cholesterol levels; but neither 2 nor 4 was as effective as clofibrate. Differences in the observed antilipidemic properties for clofibrate, 2, and 4 in the two animal models are discussed. On the basis of preliminary biological data described in this article it is concluded that tricyclic analogues 2 and 4 represent reasonable leads for the development of new antilipidemic agents.


3,3-Diphenyl-3-(2-alkyl-1,3,4-oxadiazol-5-yl)propylcycloalkylamines, a novel series of antidiarrheal agents. A series of 4-amino-2,2-diarylbutyronitriles (3) prepared for testing as inhibitors of gastrointestinal propulsive activity did not show any enhancement over such existing agents as diphenoxylate and loperamide. However, conversion of the nitrile group to a 2-methyl-1,3,4-oxadiazol-5-yl function led to compounds 5g and 5j, statistically equipotent to diphenoxylate and loperamide in the mouse and showing a very low order of analgesic activity. Structural modifications determined that the best separation of antipropulsive and analgesic effects was obtained when the amino group was bicyclic and the oxadiazole ring had a 2-methyl substituent. The most potent compounds were and analogues of diphenoxylate and loperamide where the oxadiazole ring was present, but these compounds had marked analgesic activity.


Investigation of the effect of the solvent medium on the conformational behavior of phenylethylamines by empirical method. The effect of dielectric constant (solvent medium) on the conformational behavior of six phenylethylamines has been investigated using the empirical method. Various physical properties, such as rotamer population, dipolemoment, optical anisotropy, and depolarization ratios are examined. The effective intramolecular dielectric constant has been varied from 1.0 (vacuum) to 80.0 (highly polar medium). It is shown that all these properties truly depend on the magnitude of the dielectric constant (nature of the solvent medium), but the effect is more pronounced when the dielectric constant is less than about 30.0. In addition, the effect of various groups has been assessed by using the above-mentioned properties. In general, allthe six compounds studied here possess three energy minima corresponding to one trans and two gauche forms. These energy minima have shifted only once when the dielectric constant is increased from 1.0 to 5.0. Thus, it is concluded that the nature of the solvent medium is critical in assessing percent population, ionic character, and polarizability of the molecule but not in describing the energy minima.


Physicochemical-activity relationships in asymmetrical analogues of methoxychlor. Compounds of the general formula 2-aryl-2-(p-methoxyphenyl)-1,1,1-trichloroethane have been prepared and tested for toxicity toward houseflies, pretreated for 1 h with 2mug of piperonyl butoxide. The majority of the compounds synthesized were chosen with the aid of computer programs designed to ensurewell-spread sets of minimally correlated physicochemical parameter values. A nonlinear two-dimensional representation was used to map the active region of physiochemical parameter space and a regression equation was obtained relating the observed toxicity to a combination of these physicochemical parameters. The equation indicates that toxicity increases with the hydrophobicity of the molecules but is decreased markedly by the introduction of bulky substituents into the ortho positions of the benzene ring and less markedly by bulky substituents in the meta and para positions. Substituents which donate electrons to the benzene ring by the "resonance" effect favor high toxicity. The equation performs well in forecasting the toxicity of further members of the series.


Charge distribution of histamine monocation in its "essential" conformation. With the atomic nuclei in positions earlier defined as the "essential" conformation for activity of the histamine monocation, the charge distribution is obtained by integrating the square of the molecular wave function. The results with ab initio wave functions indicate that the positive charge is evenly dispersed over the molecular skeleton and that pictures of receptors involving localized negative sites may be invalid. A detailed description of electron distribution is given.


Black students in medical schools.

Black students in medical schools. This paper presents an assessment and comparison of two groups of black medical students and the problems they confronted in medical school. Data were obtained from a sample of blacks who attended medical school during the years 1971 to 1974 and from black physicians who graduated from medical school in 1970 or before. A comparison of the two groups revealed statistically significant differences in the impact of others on the decision to enter medicine and in the sources of financial support; also the data suggest differences in perceived discrimination and in the time at which the individual decided to become a physician. The information from the 1971-1974 group illuminates the type and intensity of problems they encountered and the importance of various programs designed to aid black medical students. Overall, the findings of this study indicate a need for new efforts to recruit and to retain black students in medical schools.


Training teachers in the anatomical sciences. A number of medical schools have initiated workshops to improve faculty teaching skills. Little effort, however, has been directed toward the pedagogical training of graduate students who are destined to become future medical science teachers. To help solve this problem, the faculty of the Department of Anatomy in the University of Nebraska College of Medicine recently developed a prototype teacher training program for graduate students in anatomy. Through formal course work and practical classroom experience, students are developing the skills requisite for effective teaching of the anatomical sciences. Student and faculty response to the training program has been enthusiastic, and the objectives and structure of the program can be applied to the production of competent and skilled teachers in other areas of the basic and clinical sciences.


Cystoscopy in nonhuman primates.

Cystoscopy in nonhuman primates. Cystoscopy can be routinely performed in female rhesus macaques using a pediatric cystoscope. It reveals no major differences between the rhesus and human bladder. Ureteral physiology is also similar to that of man.


Optical principles of endoscopy.

Optical principles of endoscopy. Those optical characteristics which are of importance in the evaluation and comparison of endoscopes are, in general, easily observed and evaluated. An understanding of these characteristics and the means by which they are observed and measured is of benefit to beginning as well as experienced endoscopists. These factors will be defined and methods of observing, measuring and comparing them described.


ATP-Dependent chloride influx into internally dialyzed squid giant axons. Measurements were made of 36C1 influx into squid giant axons whose internal solutes were controlled by means of internal dialysis. When the intracellular chloride concentration was 50mM and the internal concentration of adenosine 5'-triphosphate (ATP) was 4mM, the average chloride influx was 11.6 pmoles/cm2 x sec. When the axons were dialyzed with an ATP-free solution, the average influx fell to 5.1 pmoles/cm2 x sec. The effect was fully reversible upon the return of ATP to the dialysis fluid. Chloride-36 influx in the presence and absence of ATP was found to be inversely related to the internal chloride concentration.


Use of current-voltage diagrams in locating peak energy barriers in cell membranes. The current-voltage relations obtained by integrating the Nernst-Planck equations for a variety of energy profiles are obtained. A simple and approximate method for comparing these relations is described. The method is based on using a linearized transform of current-voltage relations for an Eyring single barrier model. A parameter, gamma, related to the location of the single barrier in the Eyring model, and to the shape of the barrier in other models, is readily obtained from the slopes of the linearized relations. It is then a simple matter to determine whether a given current-voltage relation allows discrimination between any particular energy profiles. The results show that the equivalent Eyring model does not always place the peak energy barrier in the same position as other models and that quite large errors in the assignment of position may be made if such a model is used. The results are also used to test the ability of some experimental current-voltage diagrams to discriminate between various energy profiles.


Surface charges on membranes.

Surface charges on membranes. The equations of membrane potential developed by Kobatake and coworkers have been applied to the literature data on the resting membrane potential of the crayfish and Myxicola axons to derive values for the surface charge density present on the axon membranes. Some shortcomings of the method are briefly discussed. The value for the surface charge density derived for the squid axon membrane agreed with a similar value derived from measurements of shifts in Na and/or potassium conductance-voltage relations following changes in the concentration of calcium in the solutions bathing the axons.


Influence of membrane heterogeneity on kinetics of nonelectrolyte tracer flows. In a composite membrane with heterogeneous channels, prevention of net volume flow with hydrostatic pressure differences and/or impermeant osmotic solutes may induce positive isotope interaction (coupling of isotope flows) consequent to circulation of volume flow. The permeability coefficient for net flow will then exceen the tracer permeability coefficient. A permeant osmotic solute will induce either positive or negative isotope interaction, according to whether membrane heterogeneity is more marked for the test solute or the osmotic solute, respectively. Thus membrane heterogeneity may account for phenomena commonly attributed to "single file diffusion". For sufficiently small flows the general flux ratio relationship for homogeneous membranes will continue to apply.


Thermodynamic analysis of nonelectrolyte permeation across the toad urinary bladder. Permeability coefficients (P's) and apparent activation energies (Ealpha's) for nonelectrolyte permeation across the toad urinary bladder have been analyzed in terms of the thermodynamics of partition between membrane lipids and water. Particular attention has been paid to the contributions made by -CH2- and -OH groups: on the average, the addition of one -CH2- group to a molecule increases P fourfold, while the addition of one -OH group reduces P 500-fold. Using these changes in P, we have calculated the incremental free energies (delta delta F), enthalpies (delta delta H), and entropies (delta delta S) for partition, hydration, and solution in membrane lipids. The results for toad bladder have been compared and contrasted with those extracted from the literature for red blood cells, lecithin liposomes, and bulk phase lipid solvents. The partition of -CH2- groups into toad bladder and red cell membranes is dominated by entropy effects, i.e., a decrease in entropy of the aqueous phase that "pushes" the group out of water, and an increase in entropy of the membrane lipid that "pulls" the group into the membrane. This process resembles that in "frozen" liposome membranes. In "melted" liposomes and bulk lipid solvents the free energy of solution in the lipid is controlled by enthalpy of solution. PArtition of -OH groups in all systems is governed by hydrogen bonding between the -OH group and water. However, the solution of the -OH group in the toad bladder membranes is complex, and processes such as dimer and tetramer formation in the lipid phase may be involved. The results presented in this and the previous paper are discussed in terms of the structure of phospholipid bilayer membranes. Attention is drawn to the possible role of structural defects in the quasi-crystalline structure of the lipid (so-called 2 gl klinks) in the permeation of small molecules such as water, urea, methanol and acetamide.


Role of membrane-bound Ca in ghost permeability to Na and K. The permeability of red cell ghosts to K is determined by the amount of membrane-bound Mg which, in turn, depends on internal Mg. Contrasting with such effect, an increase in cellular Ca raises K permeability. To test whether this action is due to a competitive displacement of membrane Mg, the free Ca content of human red cell ghosts was altered by means of Ca-EGTA buffers. Net Na and K movements as well as Ca and Mg bindings were assessed after incubation in a Na-medium at 37 degrees C. Raising Ca from 3 X 10(-7) to 1 X 10(-2) M caused a large K efflux with very little Na gain. Under similar conditions, Ca binding was increased without affecting membrane-bound Mg. Both Ca binding and K loss were markedly diminished by either adding ATP to the hemolytic medium or increasing internal Mg at a fixed Ca concentration. A Scatchard analysis showed three Ca binding sites, two of them having high affinity. It is concluded that Ca action does not arise from a displacement of membrane-bound Mg but from binding to different sites in the membrane. Presumably, high affinity sites are involved in the control of K permeability.


Adsorption of albumin on rabbit sperm membranes. When mammalian sperm cells are exposed to solutions of albumin there are changes in the membranes of some species that resemble those that normally occur in the uterus prior to fertilization. We have shown that albumin molecules absorb on to the membranes of ejaculated rabbit sperm cells, and that the equilibrium binding constant, K, (1) varies inversely with the albumin concentration, (2) is independent of the sperm cell concentration in the range of 10(6)--10(7) per ml, (3) is independent of the time of exposure of the sperm cells to the albumin solution, and (4) decreases in the presence of Ca++ and Mg++ ions. An unusual aspect of the adsorption is that if the albumin concentration is given the symbol [A], K[A] is a constant in our measurements. This means that for virtually the entire range of [A] studied, the sperm cells bind albumin so that half of the available surface is coated and half remains uncoated. This situation is rather remarkable and it suggests a role that adsorption could play in the physical processes preceding fertilization. In purely physical systems, the optimum for the bridging and flocculation of particles that are coated with adsorbed macromolecular films occurs when half of the available surface is covered. The sperm cell appears to provide the optimal situation for interacting with itself or with another surface.


Intracortical connections in the snakes Natrix sipedon and Thamnophis sirtalis. The association and commissural connections between the four cortical areas in water (Natrix sipedon) and garter (Thamnophis sirtalis) snakes were studied by placing lesions on the cortical surface and studying the resulting degeneration in Fink-Heimer preparations. Lateral cortex projects to the outer one third of layer 1 of ipsilateral medial cortex. Dorsal cortex projects to the middle third of layer 1 of ipsilateral medial cortex. Dorsomedial cortex projects bilaterally to the inner third of layer 1 and to layer 3 of medial cortex. It also projects to layer 1 of contralateral dorsomedial cortex. Medial cortex projects ipsilaterally to each of the other cortical areas. With the apparent exception of the projection of medial cortex to lateral cortex, each projection is organized such that each rostrocaudal segment of a cortical area projects to all segments of the target area lying at the same or more caudal levels.