Tooth ontogeny in the upper jaw and tongue of the rainbow trout (Salmo gairdneri). Tooth development has been studied in the upper jaw and tongue of a series of rainbow trout embryos (Salmo gairdneri). The sequence of tooth ontogeny in the maxillary bone differs significantly from that seen in the premaxillary bone. In the maxillary bone the teeth developed in an almost perfect alternating sequence from front to back, the teeth occupying the odd-numbered tooth positions developing ahead of those occupying the even-numbered tooth positions. However an alternating sequence was not encountered in the premaxillary bone of the rainbow trout where, from tooth position 4, teeth developed in sequence, and at approximately the same rate, in both directions. The significance of this difference was discussed. The teeth on the tongue developed in an alternating sequence, the fourth tooth developing first followed by the second tooth. The teeth in positions one, three and five later developed simultaneously. Evidence was presented which indicated that resorption of a tooth may commence from its pulpal surface in association with the appearance of multinucleated giant cells and not from the external surface in relation to a successional tooth. This was particularly so in the case of lingual teeth where the successor was laterally positioned or in midline teeth which lacked successional teeth.


Effects of 6-hydroxydopamine lesions of the nucleus accumbens septi and olfactory tubercle on feeding, locomotor activity, and amphetamine anorexia in the rat. Bilateral 6-hydroxydopamine lesions of the nucleus accumbens septi (NAS) and olfactory tubercle (OT) caused enhanced intake of wet mash in 23-hr-food-deprived rats tested in photocell activity cages during restricted 30-min sessions. This mild hyperphagia was accompanied by a significant hypoactivity in the group with NAS/OT lesions. No hyperphagia was observed during a prolonged 120-min test session or in free-feeding tests conducted in the home cage. Anorexia induced by d-amphetamine (.5 and 1.5 mg/kg) was unaltered by the lesion, although the locomotor stimulant action of the drug was attenuated. A second experiment showed that the NAS/OT lesion also enhanced food intake in the photocell cages during 30-min sessions with dry food pellets but that food-associated drinking was concomitantly reduced. The results are consistent with the hypothesis that the behavioral changes caused by mesolimbic neuron destruction result in part from an inability to switch from one behavioral activity to another.


Clinical, radiographical, and histological evaluation of porous rooted polymethylmethacrylate dental implants. Forty-three porous rooted polymethylmethacrylate (PMMA) dental implants were inserted into twenty-four dogs. Successful implants were maintained for up to three years. Histological sections with the implants in situ of implants revealed a soft tissue-implant interface similar to natural teeth. Bone and fibrous tissue ingrowth into the pores attached the implant to the bone. Failures were attributed to mechanical weakness of the implant, thin buccal cortical bone, and excessive implant-gingiva interface.


A white band and a transparent zone observed at an interface between a polymerizing polyfunctional monomer and a poly(methyl methacrylate) rod, I. Macro- and microscopic studies were made of an interfacial microstructure which developed between a bifunctional monomer and a PMMA rod (or beads) during polymerization. The microstructure consisted of a white band and a blue transparent zone.


The role of cutaneous receptors in the menton tap silent period. The neuromuscular mechanisms of the electromyographic silent period are poorly understood but clinically significant. Our purpose was to isolate the contribution of cutaneous afferents from the chin to the latency and the duration of the EMG silent period. Under the conditions of our experiment, the afferents of the mental nerve have no observable influence on the latency or the duration of the silent period educed by a menton tap.


Cell production in the normal and lathyrogenic rat periodontal ligament (PDL). Thirty male albino rats weighing 200 g. each were separated into two groups. 15 rats received 0.2% 3-amino propionitrile fumarate (BAPN) in drinking water. 15 rats served as controls. Within three weeks eruption rate diminished by 50%. On the 22nd experimental day each rat received one dose of 1 microCi/g. body weight tritiated thymidine (1.9 Ci/mM). 5 rats of each group were then killed after 1 hour; 1 week and 2 weeks. The PDL cell migration rate was evaluated autoradiographically. It diminishes proportionally with the eruption rate. In the BAPN treated animals, the mean total periodontal ligament (PDL) cell count is 55.5% higher than that of the control.


Modification of human parotid saliva proteins by oral streptococcus sanguis. Polyacrylamide gel electrophoresis was used to analyze the effect of Streptococcus sanguis on the anionic proteins in human parotid gland saliva. Cell-free culture supernatants and washed-cell preparations from 23 strains of S. sanguis caused marked modification of various salivary proteins. Control studies showed that the alterations in protein profiles by the bacteria were not due to attachment of protein to the cells. Protease inhibitors were used to confirm that proteolysis by distinct enzymatic activities was responsible for most of the modifications. There was no discernible relationship between the degradation patterns and the various immunologic or genetic groups of S. sanguis. Proteins which contained high concentrations of proline were extensively degraded by S. sanguis. This effect could be blocked with the protease inhibitor phenylmethyl-sulphonyl fluoride.


Health for and by the people.

Health for and by the people. The need to extend the search for health beyond the current efforts to control disease is emphasized by citing the deficienceis of the current health care model systems. The escalating costs of health care delivery, the emphasis of the current system on treating episodic illnesses rather than chronic disabilities, and the fact that the health care system has less of an impact on health status than socio-economic and life style factors represent major deficiencies in health care delivery. Further, the fragmentation and specialization in education and health care, the exclusion of behavioral science teaching, and the teaching of behavioral determinants of diseases are additional deficiencies of health professions education. The need to develop clear and explicit national health policies, including monitoring of health both of people and communities using indices that relate not only to diseases but also to the qualitative aspect of life, is viewed as an essential prerequisite for the health care system. The assignment of much greater priority to the training of a community health worker and health educator is stressed.


Analysis of answer changes by dental students on multiple choice tests in pathology: attack on an educational myth. The outcome of answer changes on multiple choice examination questions was studied in four groups. Roughly 80 percent of changes profited students or left final numbers of errors unaffected. The ratio of number of wrong to right changes/right to wrong changes ranged from 2.5:1 to 6.2:1. These changes deviated very significantly from chance expectations. The ratio of percent of changers profiting to losing ranged from 3.2:1 to 11.7:1. Revisions resulted in clearly significant decreases in prechange numbers of errors, leading to a mean gain per answer changer of 2.4 to 5.3 percent in test score. Findings were consistent with those of others gathered from different populations and disciplines. Together, they dispel the myth that changing initial responses more often is detrimental than beneficial. Students should be encouraged to review their examinations, and to change answers if they have reason.


Manual dexterity as a predictor of quality of care among dental practitioners. This study explores the relationship between time to complete a manual dexterity exercise and quality of restorative dentistry. Ninety-seven general practitioners volunteered to take part in the study. An average of 14 patients per office were recalled and an average of five recent restorations per patient were examined clinically by trained peer reviewers. Subsequently, 74 of the 97 dentists participated in a session in which the O'Connor Tweezer Dexterity test was administered. Pearson correlations between speed on the test of tweezer dexterity and quality measures indicated that, on the average, those practitioners who took longer to complete the tweezer test achieved significantly higher scores on restorative quality.


Q factor analysis applied to describe attitudes toward dental care. This study used a modified form of Q factor analysis to introduce students to methods to identify and describe patient and provider attitudes toward dental care. Factor analysis of questionnaire results and a person by person correlation matrix allowed students to compare their own attitudes with those of their patients, faculty, and significant people in their lives. Results indicate certain issues regarding dental care on which all subjects agree. Subjects grouped themselves along different factors according to the relative importance each issue had for them. By identifying these issues and groupings, students had a systematic description of their specific "dentist-patient relationship." By including clusters of people significant in their own lives, students became personally involved in the purpose, methods, and results of the analysis.


Minimizing costs for casting gold alloy in student preclinical courses and commercial laboratory clinical use. With inflation producing a consistantly rising price for casting gold alloy, student use in preclinical courses and clinic use in commercial laboratory castings represent a significant cost to the student and the school. The New Jersey Dental School has developed and instituted a plan to decrease student cost and manage commercial laboratory fees by the purchase of a year's supply of gold. Students use the gold alloy and pay only for lost amounts, while the school replaces the gold used by the commercial laboratory.


Prevalence of mandibular dysfunction in young adults. A sample of students (739) were questioned and examined for symptoms and signs associated with mandibular dysfunction. The most frequently mentioned symptoms were headache, TMJ sounds, and pain in the face or neck. No significant differences were found between men and women with symptoms other than headache. The most common dysfunctional signs were dull occlusal sounds on repeated, firm closure of the teeth, tenderness of muscles in the jaw or head, and sounds on condylar movement. Women had a higher prevalence of these signs. Subjects who were aware of bruxism (7.9%) were more likely to have tenderness of the masseter muscle and limited mouth opening. Limited mouth opening was associated with dull occlusal sounds, pain on opening the mouth, and sounds in TMJs. Headaches were associated with tenderness in muscles and joints. Subclinical signs associated with dysfunction occurred more frequently than did awareness of symptoms.


Enhanced anticaries action from drinking water containing 5 ppm fluoride. Dental examinations were conducted on 1,878 adolescent schoolchildren native to seven US cities in five states, where the water was fluoride-deficient, fluoridated, or contained approximately 5 ppm of naturally occurring fluoride. Dental caries experience was considerably lower in all the communities with fluoridated water than in Boston, which had water deficient in fluoride, and ranged from 38% to 83% fewer mean DMF for the children in the regions with fluoridated water than for the children in Boston. Moreover, dental caries experience was significantly lower in Midland, Tex (5 to 7 ppm fluoride) than in each of the four cities with fluoridated water, and approximately 50% of the children in Midland had no caries. This report provides strong evidence that a much greater protection against human dental caries can result from a higher concentration of fluoride than is customarily recommended as best for prevention of caries. Fluoridating community waters to concentrations higher than 1 to 2 ppm fluoride, however, is not suggested because of the high risk of producing unesthetic enamel fluorosis.


An assessment of the Alabama Smile Keeper school dental health education program. An evaluation of the Alabama Smile Keeper Dental Health Education Program was necessary to determine if educating teachers to teach preventive dentistry improved the oral hygiene and knowledge of dental health of elementary schoolchildren. Four hundred seventy-five students at the Maxwell Air Force Base elementary school in grades 1 through 6 were tested using a series of written examinations and scores from a plaque index (Greene's OHI-S Index) before and after the education program. Levels of plaque were significantly reduced immediately after instruction and retention test scores were significantly lower four months later than preinstruction test scores. Written examinations proved that knowledge increased immediately after instruction and retention test scores were significantly better than preinstruction test scores.


Nitrous oxide-induced myelopathy-neuropathy: potential for chronic misuse by dentists. The myelopathy and neuropathy associated with chronic misuse of nitrous oxide are potentially reversible if the habit is discontinued. This occurred in each of the reported cases, including our case, when it was transiently discontinued. Although a causal relationship between nitrous oxide and this myelopathy-neuropathy has not been proved, the circumstantial evidence is convincing. Both physicians and dentists should be aware of this potentially serious complication of chronic self-administration of nitrous oxide, especially in persons inclined to misuse drugs. Dentists, with their access to nitrous oxide, may be particularly at risk.


Tuberculosis of the tongue.

Tuberculosis of the tongue. A case of pulmonary tuberculosis of the tongue is reported, and tuberculosis of the upper airway in a VA Hospital is reviewed. A regimen of triple antituberculous drugs, isoniazid, ethambutol, and rifampin, was prescribed. Repeated radiographs of the chest showed considerable improvement of the pulmonary lesions. The lesion of the tongue was surgically excised as a diagnostic procedure and has not recurred.


Fusion of teeth.

Fusion of teeth. Three case reports of fusion are presented. Clinical problems relating to fusion may be unacceptable appearance or alignment of teeth, and periodontal conditions. It is suggested that all succedaneous teeth that are joined or fused together by dentin be referred to as fused teeth because of the frequent difficulty in differentiating fusion and gemination in the adult dentition.


[Studies of the dental methacrylic resins. (V) Effects of molecular weight and temperature on the plasticity (author's transl)]. The plasticity, the douing time, and the working time, of the mixture of powder-liquid type methacrylic resin were measured under the various circumstances of the elapsed time and the certain temperature. Six polymethyl methacrylates, whose molecular weight was prepared by mean of gamma-ray irradiation, were used as the polymer of resin, again methyl methacrylate being used as the monomer of resin. The results obtained are as follows: (1) The plasticity is reduced with the increase of the molecular weight of the polymer. (2) The plasticity, generally, is reduced with the time elapsed, but its values appear at 10 min. and 5 min. elapsed at 16 degrees C and 23 degrees C respectively. (3) The plasticities of the mixtures of polymers with 6 X 10(4), 8 X 10(4), 20 X 10(4) and 34 X 10(4) molecular weights are increased with the increase of temperature. The plasticities of the mixtures of polymers with 60 X 10(4) and 74 X 10(4) molecular weights at 0 min. time elapsed, indicate their maximum value at 30 degrees C. At 5 min. time elapsed plasticities of all mixtures indicate their maximum value at 23 degrees C. Over 5 min. time elapsed, however, the plasticity is reduced with the increase of temperature. (4) The doughing time and the working time are reduced with the increase of molecular weight of the polymer and the temperature.


[Rheological studies on deformation for dental waxes. 2. Stress relaxation behavior of inlay wax (author's transl)]. The rheological properties of inlay wax were investigated by experiment of stress relaxation, thermal expansion, thermal analysis and X-ray diffraction. The results obtained were as follows. The solid-solid phase transition caused by phase transition of paraffin was observed. The stress relaxation curves of inlay wax were obtained at various temperature, and from these curves the stress relaxation master curve was composed by application of time-temperature superposition principle. The temperature dependence of sift factor was devided into two regions of Arrhenius type, and the activation energy was about 60 kcal/mol at the temperature lower than 23 degrees C and 120 kcal/mol at higher temperature. This fact suggests that the relaxation mechanism of inlay wax can be classified into two different modes. The relaxation mechanism at lower temperature region is explained by crystalline relaxation, and at higher temperature is considered to depend upon the solid-solid phase transition process of inlay wax. Calculating from the activation energy, for each 2 degrees C rise in temperature, the rate of rheological change for inlay wax is approximately two-fold at lower temperature region, and about four-fold at higher temperature region.


[On the ageing characteristics of commercial Elgiloy (author's transl)]. An age-hardening phenomenon in commercial Elgiloy was studied by means of resistivity, hardness and X-ray diffraction. The increase in hardness during ageing in the range 400-800 degrees C was accompanied by a pronounced increase in resistivity. The X-ray diffraction study showed that any precipitate was not taken place by ageing. The proposed mechanism of hardening during involves the segregation of solute atoms to stacking faults by the SUZUKI's chemical interaction mechanism.


[Effects of gold on age-hardening in Ag-25 wt. % Pd-7 wt. % Cu alloys (author's transl)]. Effects of third elements (0, 1, 2, 4, 6, 8 and 12 wt. % Au) on the age-hardening in Ag-25 wt. % Pd-7 wt. % Cu alloys were studied by means of electrical resitivity, micro-hardness measurement, optical microscopy observation and X-ray diffraction. The results are summarized as follows. (1) The temperature range of an initial increase in resistivity was lowered with increasing concentration of gold. (2) The age-hardening process was retarded by the addition of gold. (3) Changes in X-ray diffraction patterns which was aged at lower temperature range exhibited that continuous precipitation process. On the other hand, changes in diffraction patterns aged at higher temperature range showed discontinuous precipitation process. (4) The lattice parameters of alpha phase and alpha2 phase (Ag-rich) were found to decrease with increase in gold content, while the lattice parameter of PdCu type superlattice was found to increase with increase in gold. (5) The nature of the interface between precipitates and the matrix was discussed on the basis of the changes in lattice parameter obtained.


[Studies of calcium phosphate glass-ceramics--development of dental materials. (Part 2) Acid resistance--(author's transl)]. It is well known that minerals of bone or tooth are essentially of CaO-P2O5 system. Glass and the crystallized product, i.e., so-called "glass-ceramics" of which chemical composition is 55 CaO . 45 P2O5 (in mole %) and have been developed for biomaterials were subjected to chemical durability test. Human enamel was also tested for the comparison of the data with them. All the specimens were ground to powders in size from 74 to 140 micrometer. A hundred milligram of the powders were immersed into 100 ml. of N/10 acetate buffer (1 mol acetic acid) solution (pH 4.1) at a constant temperature of 37 degrees C. Amount of Ca2+ and P5+ dissolved were determined by an atomic absorption method and Fiske-Subbarow method, respectively. The order of dissolution is human enamel greater than glass greater than glass-ceramics: the amount of Ca2+ (SCa) and P5+ (Sp) with soaking time (t) was expressed by the following equations, :formula: (see book). The glass and the glass-ceramics show good resistance against a weak acid.


[Studies on the cytotoxic action of various silicone rubber impression materials by means of cell culture (author's transl)]. Biological test of the silicone rubber impression materials was done by utilizing tissue cultures of L strain cells. Criteria for cytotoxicity were based upon response index in agar diffusion method which was determined by zone index and lysis index, and morphological observations of the cells. The materials used were chosen among those which were commercially available. Base material, catalyst, unset and set mixes of both materials were tested respectively. X-ray fluorescence analysis of the material was also performed. Following results were obtained. 1) Base material of all the materials showed zone index of a range between 11.8 mm and 18.6 mm. On the otherhand, lysis index was relatively small and minimum response index was 11.8 mm/8.6 mm. The cells appeared normal after cultivation with the base materials, though tissue culture medium became opaque due to dissolution of the base materials. It is revealed that the above results mean little cytotoxicity to the cells. 2) Catalyst, on the otherhand, yielded intense cytotoxicity. Minimum response index for the catalyst was 13.4 mm/14.8 mm. Morphological observation was parallel to the results of agar diffusion method. 3) Unset mixes also yielded intense to moderate cytotoxicity. 4) Set mixes showed a similar in level of cytotoxicity to the unset mixes. 5) X-ray fluorescence analysis of the materials revealed existence of such elements as Si, Sr, Sn, S, Cu and Fe. Moreover, Zn was found in materials A, B, C, D and E; P in materials A and B, and Pb in materials E and F. However, it was unable to show what compound was formed by these elements. It is expected that the present results could give a clue on animal experiments or clinical use from the view point of biocompatibility of silicone rubber impression materials.


[Recrystallization process in the 20 carat dental gold alloy (author's transl)]. An annealing process of the 20 carat dental gold alloy was studied by hardness testing, electrical resistivity measurement and optical microscopic observation. The material was cold rolled to 67.4% and 90.7% in reduction and subsequently annealed in the temperature range from 300 degrees to 500 degrees C. Microscopic observation, electrical resistivity and hardness testing revealed that the annealing process were three distinguishable stages, recovery, recrystallization and grain boundary migration. Activation energies, the order of the reaction involved, and frequency factors for various annealing processes were established.


[Effects of electrical stimulus upon L-strain cells. (Part 2)--Response of the cells to alternative current prior to cultivation (author's transl)]. In order to examine the effects of voltage, current time and frequency of the alternative current on cell multiplication and morphology during initial stage of cell cultivation, alternative currents of varying intensity were applied to the L-strain cells in the tissue culture medium, i.e. YLH solution supplemented with 5% bovine serum which was considered as an electrolyte solution. The following results were obtained: 1) The rates of cell multiplication depended on the frequency (0.01 Hz-10 KHz), when voltage and current time were kept constant. In particular, they were remarkably depressed in the low frequency range. In a certain frequency range, a maximum value of the rates of cell multiplication was recorded. It was considered that there is certainly a least inhibitive frequency range in the rates of cell multiplication. 2) The lower and the shorter the voltage and current time were, the lower were the frequency level at the threshold of marked inhibition of the rates of cell multiplication brought. 3) An arbitrary equation for the relationship between the rates of cell multiplication and frequency was determined: The rates of cell multiplication upon cell multiplication were proportional to (A + log F), where A was a constant value and F was the applied frequency. According to the equation above, the depression upon cell multiplication was calculated, when the values of voltage and current time were given. 4) It was found that the results of the rates of cell multiplication were parallel to the results of the morphological observations. It was presumed that the main factor governing cell multiplication during application of the alternative current was due to change of the compositions of medium which was electrolyzed.


[A study on the effects of beryllium addition upon biological and physical properties of dental cobalt-chromium alloys (author's transl)]. The effects of beryllium addition to a dental cobalt-chromium alloy on biological compatibility as well as physical properties were examined and the following results were obtained. 1. Slight, but significant depression of the rates of cell multiplication was obtained with the experimental groups, i.e., alloy with no beryllium added as well as alloys with beryllium of up to 3.0 per cent by weight, compared to control group, which contained no alloys, but a glass disk. Within the experimental groups no significant difference in the rates of cell multiplication was found between the alloys with beryllium addition ranging from zero up to 2.0% by weight. However, alloy with 3.0% beryllium yielded slight, but significant depression of the rates of cell multiplication. Pure beryllium metal revealed severe cytotoxicity. 2. Cell morphology of the experimental groups confirmed the above results of the rate of cell multiplication. 3. Increase of beryllium within the alloys resulted in increase of tensile strength as well as Rockwell hardness, while elongation and fusion temperature were brought down. 4. Metallographs of alloys and cast specimens confirmed the results of the mechanical properties. The more beryllium was added, the smaller was the alloy crystal observed. 5. Loss of beryllium in the alloy was found during such procedures as melting each metal for making up alloys and casting. It is considered that the present results will be able to lend suggestions to beryllium use in dentistry with regard to biological compatibility as well as physical properties.


[Studies on the marginal leakage around various restorative materials. Part 1: Testing method and condition (author's transl)]. Standardized cavities prepared in bovine teeth were restored with 4 types of filling materials, lathe-cut amalgam, spherical amalgam, silicate cement and composite resin. Restored teeth were immersed in 4 degrees C and 60 degrees C dye solution alternately by automatic device which makes it possible to change the immersion interval and number optionally. By means of measuring the depth of dye penetration, the marginal leakage induced during the thermal change was evaluated and the effects of the immersion interval and number were investigated. Results are as follows. 1) It is possible to obtain the marginal leakage quantitatively by means of measuring the depth of dye penetration. 2) The marginal leakage around various restorations are significantly influenced by the immersion interval and number. 3) The depth of dye penetration varies with types of filling materials. 4) The optimum immersion interval and number are 2 minutes and 60-120 times to evaluate the marginal leakage around various restorative materials.


[Dilatometry of gypsum bonded investment (author's transl)]. Although many investigations on the thermal expansion of dental investments have already been done, the conditions upon which thermal expansion was measured were not always definitely shown and the phenomena on thermal behavior of dental investments were not reasonably interpreted. In this investigation the effects of W/P ratio of samples, heating rate and furnace atmosphere were studied by "Push Rod" Dilatometer in order to attempt to standardise dilatometry of dental investments. All experiments were designed with two-way layout techniques. The main results were as follows, 1) W/P ratio, heating rate and furnace atmosphere have significant effects on the thermal expansion curves of the gypsum bonded investments. 2) One steep expansion and three stages of shrinkage in heating process of these investments from room temperature to about 900 degrees C were observed. 3) The quantity of the steep expansion, first and second stages of shrinkage and the expansion at 650 degrees C were affected by W/P ratio. 4) The temperature at which the steep expansion or shrinkage occurred were affected by heating rate. 5) Furnace atmosphere affected on both quantity of the steep expansion or shrinkage and their temperature. It also affected on the expansion at 650 degrees C. Then, these factors should be considered in dilatometry of gypsum bonded investments and in dental practice.


[Fundamental studies of elastic impression materials (part III). Viscoelastic properties from start of mix for alginate impression materials (author's transl)]. The viscoelastic properties during setting of commercial alginate impression materials vary considerably from one product to another. In order to obtain an acculate impression, it is important to understand these differences in viscoelastic properties. The purpose of this investigation is to develop the method of measuring viscoelastic properties during setting and to determine precise setting characteristic of commercial alginate impression materials. The materials used in this investigation were mixed according to the manufacturer's recommendation at a temperature of 23 +/- 0.5 degrees C and transferred after 60 sec from start of mixing to the testing instrument in an air cabinet at 32 +/- 0.5 degrees C and allowed to set. The mixing time for materials was 30 seconds. The apparatus used in this investigation is the oscillating rheometer modifiied by Inoue and Wilson (1977). The working times of impression materials procured at retail in alginate paste were shorter than those of alginate Impression materials in powder. Alginate, Jeltrate (regular), Xantalgin (normal) and Zelgan had long working time. In case of these materials, the variation of elastic modulus during the time of working was small markedly. All other materials used in this investigation, with the exception of Alginate, indicated a considerable increase torsional shear modulus after the setting time determined by the method of British standard.


Development of lingual brachet technique. (Esthetic and hygienic approach to orthodontic treatment) (Part 1) Background and design. The present study relates to a development of the new technique and the new appliances, for the treatment of malocclusion and minor tooth movement. The primary purpose of the present study consists in to reduce mental burden of the patients receiving orthodontic treatment and to improve effect of the treatment further by making the appliance invisible when mouth is opened. The second purpose of the study is in orthodontic treatment carried out from lingual side, to control all teeth movement in oral cavity in three dimensions so that the normal occlusion may be operated. The third purpose of the present study is to make the exchange of wire readily when the wire with bigger elasticity is exchanged by turns during the process of the treatment. The background and the design of appliances for the lingual-bracker technique(lingual-bracket mushroom arch wire technique) is found out in this report.


[Development of lingual-bracket technique. (Esthetic and hygienic approach to orthodontic treatment) (Part 2) Manufacture and treatment (author's transl)]. The present study relates to a development of the new technique and the new appliances, for the treatment of malocclusion and minor tooth movement. The primary purpose of the present study consists in to reduce mental burden of the patients receiving orthodontic treatment and to improve effect of the treatment further by making the appliance invsible when mouth is opened. The second purpose of the study is in orthodontic treatment carried out from lingual or palatal side, to control all teeth movement in oral cavity in three dimensions so that the normal occlusion may be operated. The third purpose of the present study is to make the exchange of wire readily when the wire with bigger elasticity is exchanged by turns buring the process of the treatment. The product of appliances and the outline of treatment for the lingual-bracket technique (lingual-bracket mushroom arch wire technique) is found out in this report.


[Effect of porosity on strength and hardness of dental stone (author's transl)]. The strength and hardness of dental stone were found to have better a correlation with porosity than with water-powder ratio. Within the range of porosity of less than 34 vol-%, the strength and hardness varied logarythmically with a linear change in porosity.


Cell contact to metal surface.

Cell contact to metal surface. In order to observe cell contact with various metals, the pulp cells of human origin were grown on vacuum evaporated metal film in such tissue culture mediums as Medium 199 supplemented with 10% calf serum. Medium 199 (serum free), Hanks' balanced salt solution (serum free) and calcium and magnesium ions free balanced salt solution (serum free). Secondary electron images of the cells were observed. The following findings were recorded. 1) Differences of metal did not give any discernible effects in cell morphology, except cytotoxic metals which gave severe deteriorating effects to the cells. 2) Lack of serum appeared to give unfavourable effects to cell growth, but no decisive, positive evidences for cell contact were obtained. 3) The effect of calcium and magnesium ions on cell contact was not substantiated. Importance of accumulation of informations on cell to material contact was stressed in order to develop various biomaterials compatible to the cells. Further approaches to understand the phenomena in the subject were discussed.


[Polymerization shrinkage and fitness of denture (author's transl)]. Polymerization shrinkage causes dimensional change of denture during the processing. We can not control the amount of shrinkage but can control the initiation points and the direction of polymerization. Heat conductivities of dough and mould, the distance from heating or cooling place, and amount of MMA etc. have influence on the polymerization. Polymerization shrinkage mainly appears on the point where polymerize last. In the case of heat processing the shrinkage mainly appeared on the point where heat supply was slow. On the other hand in that of self-curing resin, the polymerization starts at the center of the mass when the mould is immersed in an ice water bath and the shrinkage appeared on the surface of mass. Dentures were prepared by heat processing resin conventionally heated in a water bath, heated from mucous side only on a heat plate, and self-curing fluid resin. An amount of filled light body silicone impression materials between the denture and cast was minimum in the case of the one side heat processed denture. That was middle in the self-cured. The maximum case was conventional heat cured denture.


[Preparation of clear thermosetting resin for veneered crown from several bisMEPP monomers (author's transl)]. The whitish translucent shade of a thermosetting resin cured from a mixture of a 2,2-Bis (p-methacryloxy (ethoxy)1-2 phenyl)-propane monomer and PMMA pearls makes it difficult to reconstruct a shade of the natural tooth. The attempt to improve the transparency of the mixed polymer was made in this study. Varying the molecular weight of BisMEPP monomer, PMMA polymer and curing temperature, cured specimens were prepared and their transparency was measured with a spectrophotometer. The results obtained are as follows. 1) In any molecular weight of PMMA, BisMEPP with 2.3 to 3.3 average number of ethylene oxide linkage showed the highest transpalency on the specimen. 2) With increasing the curing temperature, transpalency of the specimens made from BisME4.0 PP increased. With another molecular of BisMEPP, transpalency of the cured specimens showed the highest transpalency at the curing temperature of 120 degrees C. 3) With increasing the molecular weight of PMMA, the transpalency increased.


[Re-examination of dehydration process of gypsum by micro-DTA (author's transl)]. The results obtained by macro-DTA were not reproducible because they were largely influenced by the packing method, the amount of samples and many other factors related to each apparatus. The dehydration process of gypsum was investigated by micro-DTA in this study. The results were compared with those of macro-DTA studies. Two endothermic peaks were generally observed. These peaks tended to overlap with the increase of particle size. As the water vapor pressure decreased, the two peaks shifted to lower temperature and finally overlapped completely. The effect of the amount of samples was very similar to that of the atmosphere. When the amount was less than about 1 mg, only a single peak was observed. The dehydration process of gypsum was discussed on the basis of a phase diagram of the system of CaSO4-H2O. Moreover, the activation energies of the first and second dehydration reactions were calculated by Kissinger's method. The former was about 25 kcal/mol and the latter was about 24 kcal/mol. They werein good agreement with those obtained by other workers.


[Studies on dental self-curing resins. (17). Adhesion of PMMA with bovine enamel or dental alloys (author's transl)]. We synthesized 4-methacryloxyethyl trimellite acid (4-MET) and anhydride (4-META), and tried them as a reactive comonomer for adhesives to bovine enamel. In the case of non-etched enamel, tensile adhesive strength was 40-50 Kg/cm2 after one day immersion in 37 degrees C water, but it decreased below 10 Kg/cm2 after a month immersion in 37 degrees C water. It could be concluded that this adhesion was not sufficient for practical usage. Then we applied this method to an etched enamel. After a series of experiments we concluded that it was necessary to etch bovine enamel surface with 30% citric acid for practical usage. Adhesion of some dental alloys with a PMMA rod was also studied and adhesive strength in Co-Cr alloy was over 150 Kg/cm2 either after one month immersion in 37 degrees C water or 60 times thermal cycles between 4 degrees C and 60 degrees C.


[Cytotoxicity of some dental cements in a cell culture system (author's transl)]. Four dental cements of zinc phosphate cement, polycarboxylate cement, zinc oxide-eugenol cement and epoxy resin cement have been tested by means of cell culture method using L strain cell. The cells were cultured with a test piece of the cements in the incubator of 37 degrees C. The test pieces of powder, liquid, un-set cement and set cement were prepared. Cell multiplication, medium pH and zone index in agar diffusion method were measured and also cell morphological changes were observed around the test piece. Test pieces of the four un-set cements showed cytotoxic action at 2 hours administration, although the cytotoxicity of their cements decreased after setting. pH 7.2 of the normal medium was changed to 4.6 with un-set zinc phosphate cement. The other cements affected slightly comparing with zinc phosphate cement. The largest zone index which indicates degree of cytotoxicity, were observed around the test piece of the liquid of zinc phosphate cement. In this study, a biocompatibility of four dental cements was investigated and the following results were obtained. 1. Zinc phosphate cement showed strong cytotoxic action under the un-set condition, and the cytotoxicity almost disappeared after setting. 2. Polycarboxylate cement showed weaker cytotoxic action than zinc phosphate cement. However the cytotoxicity did not disappear after setting. 3. Zinc oxide-eugenol cement showed cytotoxic action which was similar to polycarboxylate cement, but it was slightly stronger than that of polycarboxylate cement. 4. Epoxy resin cement showed the weakest cytotoxic action than other three cements under the un-set condition. The cytotoxicity of set epoxy resin cement was strong, followed by zinc oxide-eugenol cement.


Evaluation of facial osteotomy with the aid of Moiré contourography. The Moiré method, a new technique for recording contour lines on the body surface, was applied to the evaluation of facial osteotomy in patients with oro-facial disharmony. The advantages of the methods are three-dimensional, with no contact. Small changes of the facial profile after osteotomies were measured three-dimensionally and the prediction of probable facial contour changes by osteotomies is discussed.


Correction of jaw deformities involving simultaneous osteotomy of the mandible and maxilla. A one-stage surgical correction of gnathic deformities involving both jaws is described. It permits both the establishment of a normal occlusion and correct alignment of the occlusal plane to the skull. The osteotomy commences with the mandible. Its new position is oriented to the (as yet) untouched maxilla with the aid of an intermediate occlusal splint produced as a result of cephalometric evaluation and cast model surgery. The mandible is secured at its osteotomy sites by bone screws, in the correct final position. The maxilla is then oriented to the mandible, now correctly positioned with the aid of a second, preformed occlusal splint again produced on the basis of cast model surgery. Following intermaxillary fixation and internal wire suspension the splint is left in place until bony consolidation has taken place. External fixation is not required. The procedure enables the cephalometrically established measurements for the movements of both jaws to be easily reproduced with a high degree of accuracy. The technique is described in detail and discussed on the basis of clinical examples.


The tongue flap for reconstruction in a case of Möbius syndrome. A case report. This paper deals with the extension of the tongue flap technique for reconstruction of deficient perioral structures in a case of Möbius syndrome. Some important surgical considerations, such as the vascularisation of the tongue, design of the flap, location of the flap base etc, are discussed and the operative procedures and the result are demonstrated.


Diagnostic and therapeutic problems of myxomas (myxofibromas) of the jaws. During the period from 1969 to 1977 11 cases of myxoma or myxofibroma in the jaw region have been treated at the Maxillofacial Surgery Clinic of the University of Mainz. Various kinds of diagnostic problems are discussed. We observed, inter alia, rapid tumour growth and a imitative dynamics in the radiographs, giving rise to a suspicion of malignancy in some cases. The locally infiltrative type of growth of myxomas must be taken into account during therapy, since insufficiently radical management is liable to be followed by a recurrence.


Plunging or cervical ranula. Review of the literature and report of 4 cases. A review of the literature pertaining to plunging ranula is presented with special emphasis on the historical development of the various aetiological theories and treatment recommendations. Also 4 cases of plunging ranula are presented; three were treated by extirpation of the sublingual gland and one was treated by exteriorization of the ranula into the oral cavity. The treatment methods used here are discussed in relationship to the accepted aetiological theory.


Results of treatment of midfacial fractures. Indications for exploration and drainage of the maxillary sinuses. The results of late follow-up of 45 patients with midfacial fractures are reported. The intervals between accident and follow-up ranged from 6 months to 6 years. Methods of treatment are discussed, with emphasis on frontomaxillary or zygomaticomaxillary wire suspension and external fixation. The late results and complications in this series are compared with those previously described in the literature. Since opinions differ as to the basic necessity for surgical exploration and drainage of the sinuses following midfacial fracture, the influence of the latter procedure was investigated statistically. In the group of Le Fort II and III fractures the results following revision were compared with those in sinuses which were not revised: the radiographs (chi2 0.415) and sensory testing (chi2 1.668) showed no significant differences. This supports our opinion that surgical exploration and drainage of the sinuses should continue to be limited to cases which fulfill the strict criteria described in this paper.


Localized nodular synovitis of the temporomandibular joint. A case report. A case of localized nodular synovitis of the temporomandibular joint is described and discussed. There are no cases previously reported in the literature. The distinction between synovitis of the villo-nodular type and that of the localized nodular type can be made, given the close collaboration of clinician and pathologist. The recognition of these to clinical entities of nearly similar histomorphological pattern is of great importance, as they differ in clinical course, treatment and prognosis.


Copper in dental amalgams.

Copper in dental amalgams. The relationship between microstructure and physical and electro-chemical properties of the copper-containing dental amalgams has been discussed in an attempt to understand the role of copper in currently used dental amalgams.


A study of the contour and external surface of class V composite resin fillings. Twenty-five Class V Composite-resin, Adaptic fillings were prepared on extracted human teeth under five different matrices. White stones and flame diamonds were used as polishing devices. The smoothest surface was obtained with celluloid strip and the most acceptable contour obtained with preformed matrix.


Comparison of the accuracy of denture bases by a non-parametric method. A comparison of the accuracy of denture bases made from a conventional acrylic and four modified acrylic resins was made with the use of a non-parametric method. Twenty-five identical maxillary stone casts were made and five dentures for each resin were processed by conventional compression moulding techniques. The fit of each denture at the molar-to-molar region on its cast was evaluated by five evaluators who independently ranked the twenty-five dentures from best to worst fit after processing, after polishing, and after storage in water at 37 degrees C for 42 days. The ranking data were analysed by Kendall's coefficient of concordance, the Kruskal-Wallis statistic, and the Mann-Whitney test. Excellent agreement among observers was obtained. After storage in water, two modified acrylic resins, Hydrocryl and Vitalon II, had a better fit on their casts than the conventional acrylic, Lucitone Hypro. Luciton 199 had the same and Hircoe had a poorer fit than Lucitone Hypro.


Bite force and oral function in complete denture wearers. Oral function was evaluated in complete denture wearers by using a questionnaire, clinical examination and bite force measurements. Ten patients with satisifactory and ten with unsatisfactory dentures were studied and six of the latter patients were reexamined 1 year after the insertion of new dentures. The bite force values were compared with those obtained in ten dentate controls. No significant differences in bite force were found between the satisfactory and unsatisfactory denture groups. Individual values varied much in both groups. The six patients re-examined were satisfied with their new dentures and thought they had improved chewing but no significant increase of bite force was found. The maximal bite force was 5-6 times greater in the dentate subjects than in the denture wearers. Edentulous persons are very handicapped in masticatory function and even clinically satisfactory complete dentures are poor substitutes for natural teeth.


Reproducibility of the normalized electromyographic recordings of the masseter muscle by using the EMG recording during maximal clenching as a standard. A method of normalizing the integrated EMG recordings from the masseter muscles is introduced. For each subject investigated the maximal clenching force is remarkably constant and reproducible. This makes it possible to normalize the integrated EMG recordings to the EMG activity at the maximal clenching force without having to measure this force at the beginning of every experiment. These normalized integrated EMG activities give a good quantitative impression of the static force exerted by the masseter muscle, and therefore can be compared quantitatively over several experiments. The realtionship between the normalized integrated EMG activities and the clenching force is linear up to approximately 80% of the maximal clenching force.


A clinical study of marginal integrity and tarnish behaviour of three Cu-rich amalgam systems. Three high Cu-gamma2 free amalgams and one conventional amalgam were used in a clinical study to evaluate degree of marginal integrity and surface discoloration occurring for time periods of up to two years. Two hundred and seventy restorations were placed in Class I and II cavities in sixty-two paedodontic patients. Amalgams were prepared from conventional alloy, Cu admixed, Dispersalloy and three parts 50Ag-20Sn-30Cu mixed with one part conventional alloy. Restorations were evaluated by three groups of clinicians. Ridit means obtained from all three groups of evaluations were in good agreement. The lower ridits indicate better marginal integrity and less tarnish. Marginal integrity of amalgams prepared from Cu-admix did not differ appreciably (0.41) from the ridit associated with initial placement (0.39). Conventional amalgams had the highest ridit (0.65) for marginal integrity whereas the ternary/conventional and Dispersalloy restorations were intermediate (0.55 and 0.52). The ridit for tarnish and surface discoloration was decidedly higher for the Cu-admix (0.73) than for the other systems investigated which had ridits of the order of 0.50 compared to an initial ridit for tarnish of 0.28.


The relationship between bruxism and temporomandibular joint dysfunction as shown by computer analysis of nocturnal tooth contact patterns. Whilst there are many causes of temporomandibular joint dysfunction, one of the most frequently encountered is bruxism. The two conditions have many aetiological factors in common and there is a rational physiological reason why bruxism could cause temporomandibular joint dysfunction. In fact, experimental bruxism performed under laboratory conditions has been found to cause such joint dysfunction. This contention is supported by direct measurements of nocturnal tooth contact. Patients with temporomandibular joint dysfunction were found to differ from control subjects to a degree which was statistically significant.


Treatment planning for the management of selected dento-facial abnormalities. Existing treatment planning aids for the management of dento-facial abnormalities do not adequately assess the neuromuscular status of the oro-facial soft tissues. Where an element of mandibular overclosure exists the patient assessment technique provides a reproducibile and clinically acceptable occlusal vertical dimension of occlusion. In the three cases treated a functional impression technique for establishing the upper lip support produced a reproducible profile which was both aesthetically and functionally satisfactory.


Condylar displacements related to dynamic and static recordings of the comfortable zone. In a previous study it was found that the distance between the borders of the comfortable zone was considerably wider when the zone was recorded statically rather than dynamically. However, it was not reported how condylar displacements may be related to the zonal borders. Therefore, an attempt is made in the present study to translate zonal border recordings into the equivalent amount of condylar rotation. Using a dental articulator, it was found that the condyles rotated 4.96 degrees, when the comfortable zone was recorded statically, and 2.50 degrees, when the zone was recorded dynamically. The difference, 2.46 degrees, was statistically significant (P less than 0.001).


Leukemic infiltration of the testis during long-term remission. Of 33 boys with acute lymphocytic leukemia treated at the Cincinnati Children's Hospital during 1971--1974, 14 remained in clinical and bone marrow remission for periods longer than 2.5 yr. Of these 14 patients, 8 then developed testicular leukemia. In 7 of these 8 patients, testicular infiltration was the first or only evidence of relapse. In 2 of the patients the gonads were not grossly abnormal, and testicular relapse was discovered as a result of routine wedge biopsy before therapy was to have been stopped. This experience has led to our policy of routine testicular biopsy in boys with acute lymphocytic leukemia who have had continuous remission for 3 yr and who are otherwise candidates for discontinuance of maintenance therapy.


The presence of "creeping attachment" in human gingiva. Standardized photography was used to determine the presence of "creeping attachment" after free autogenous graft procedures on localized areas of root recessions. "Creeping attachment" occurred in all seven experimental teeth with an average of 0.89 +/- 0.46 mm and a range of 0.38--0.61 mm during a period of 1 year. The results encourage the use of grafts over exposed root surface in an attempt for gingival coverage.


Preliminary clinical studies of bioceramic in periodontal osseous defects. In six patients, porous tricalcium phosphate ceramic (400 to 500 micrometer pore diameter and 50% pore volume) was used to repair naturally occurring periodontal osseous defects. These patients were evaluated clinically, radiographically and hematologically. The clinical evaluation indicated that there was no adverse inflammatory response at the implant site except the anticipated immediate postsurgical trauma. Radiographically, there was a significant increase in bone height with a mean gain of 5.2 mm. Whether or not this gain consisted of bone and/or ceramic is yet to be conclusively determined. The SMA-12 blood chemistry study revealed that no significant change occurred pre- or post-operatively (P less than 0.01). Although the number of patients in our study was limited, the results are very promising. The ceramic is nontoxic to human tissue and repair of the periodontium is most likely obtainable, the desired objective being the restoration of the natural state of the periodontium.


The natural history of periodontal disease in man. The rate of periodontal destruction before 40 years of age. This longitudinal study of randomly selected Norwegian students and academicians has shown that 50% of the 17-year olds have lost no periodontal support, and the other 50% exhibited slight localized loss of attachment primarily on buccal surfaces of first molars and first bicuspids of both jaws. At 21 all students show one or more of these lesions as well as loss of attachment on interproximal surfaces. At 30 years of age the mean cumulative loss is still less than 1 mm. As they approach 40 years of age the mean individual loss of attachment is slightly above 1.5 mm or 10% of the total periodontal support, and the mean annual rate of attachment loss is 0.08 for interproximal surfaces and 0.1 mm for buccal surfaces. No case of juvenile periodontitis (periodontosis) or adult aggressive periodontitis were seen in this population. Seventy percent of the 15-year-old Sri Lankans have no or very little loss of periodontal support. However, approximately 30% exhibit localized lesions measuring between 2 and 9 mm and more than 1% have one or more root surfaces with 10 mm loss of attachment or more. In this age group the lesions occur at the interproximal and buccal aspects of lower central incisors and in first molars of both jaws. At 30 years of age the mean loss of attachment is 3.11 mm and approximately 25% of the tea laborers have lesions extending 10 mm or more below the cemento-enamel junction. As the Sri Lankan approaches 40 years of age the mean loss of attachment is 4.50 mm and the mean rate of progress of the lesion is 0.20 mm per year for buccal surfaces and 0.30 mm for interproximal surfaces. This study suggests that without interference the periodontal lesion progresses at a relatively even pace and that the progress is continuous.


Psychological factors involved in maxillofacial prosthetics. 1. No significant difference existed between the MMPI means of the test group and the MMPI means of the Mayo Clinic patient group. 2. The means of the test group and the Mayo Clinic patient group deviated from the MMPI normative data. 3. No apparent change in personality of the test group was suggested by the MMPI. 4. A much larger percentage of the patients than expected failed to complete the initial MMPI. One patient refused, and four patients had a raw score of "cannot say" responses greater than 120, thus invalidating the test. 5. The changes in the means of the ACL scales of total number checked, autonomy, change, and abasement were significant (p less than .05). 6. The patient became more outgoing and optimistic, as measured by the ACL, during the immediate postoperative period. 7. Speech and mastication were problems for some patients even after prosthodontic rehabilitation. 8. Most of the rehabilitated patients resumed their normal social habits. 9. The patients in the study seemed to respond to the new situation according to their already existing personality structure.


Biocompatibility evaluation of casting alloys in hamsters. A number of base metal and low gold-content alloys were evaluated in hamster cheek pouches for biocompatibility. No adverse weight changes and no abnormal behavioral patterns were noted in any of the test groups over the 14-day period of the study. Gross examination of the cheek pouches containing the alloys was no different from that of the controls. None of the alloys tested showed significant adverse histopathologic reactions. The recorded changes in incidences and degree of response were essentially no different from those of the negative control material.


Pharmacokinetics of levamisole.

Pharmacokinetics of levamisole. Levamisole is rapidly absorbed following oral, intramuscular, or subcutaneous administration to several animal species. Extensive metabolism occurs with rapid excretion of drug and metabolites, equally distributed between urine and feces in rats. In man a single oral dose of 150 mg produces a peak levamisole plasma level of 0.5 microgram/ml after 2-4 hours. Unchanged drug represented only one third of total plasma radioactivity. Urinary and fecal excretion of radioactivity amounted to 60% and 4% respectively after 24 hours, with only small amounts of unchanged drug being excreted. Levamisole syrup and tablets were bio-equivalent.


The place of levamisole in the armamentarium for rheumatoid arthritis. Levamisole is a welcome addition to the list of penicillamine-like drugs. Many patients fail to respond to these drugs or develop adverse reactions requiring withdrawal of treatment. Levamisole will be a useful alternative for these patients.


Measurements of humoral immunity during treatment with levamisole in rheumatoid arthritis--a review. Treatment with levamisole in patients with rheumatoid arthritis reduced significantly titers of rheumatoid factor and the amount of circulating immune complexes as determined by the Clq binding activity. It took between three and six months to observe a significant effect. Levamisole treatment had less effect on the amount of immunoglobulins in serum: the values were rarely abnormal before treatment and the changes were small, but reached statistical significance at six months. The effect on complement and complement components could not be evaluated as properly controlled studies were lacking.


The non-hematological side effects of levamisole in the treatment of rheumatoid arthritis--a review. The non-hematological side effects of levamisole include (1) sensorineural reactions, the most common of which is alterating of taste and smell; (2) idiosyncratic or allergic reactions such as rash and a febrile, influenza-like illness; and (3) gastro-intestinal symptoms. The sensorineural reactions are seldom of sufficient severity to require discontinuation of treatment. Rash and febrile illness have resulted in withdrawal of levamisole in 7% and 1.5% of cases, respectively, but usually remit spontaneously within a brief interval and are not hazardous except when associated with agranulocytosis. Rash due to levamisole occurs more frequently in rheumatic disease patients than in other conditions. Gastro-intestinal symptoms are mild, quickly reversible, and possibly dose-related; some controlled trails have shown a similar frequency of gastro-intestinal symptoms in the placebo group.


A study of the hematological side effects of levamisole in rheumatoid arthritis with recommendations. Agranulocytosis, which must be differentiated from leukopenia, was seen as the most severe side effect of levamisole in the treatment of rheumatoid arthritis (RA). By sending a detailed questionnaire to each investigator known to have been confronted with leukotoxic side effects, data were collected on 88 patients with agranulocytosis, 43 patients with leukopenia and three with thrombocytopenia. The presence of HLA B27 in seropositive RA patients was found to be an important predisposing factor for agranulocytosis. This blood dyscrasia caused by levamisole was similar to the agranulocytosis found with other antirheumatic and anti-inflammatory drugs and could be classified as agranulocytosis of the immunological type. In this form no bone marrow toxicity occurred and the agranulocytosis was always spontaneously reversible on discontinuation of the drug. Although the incidence of agranulocytosis did not seem to be reduced by any of the treatment schemes, high risk patients could be detected by the single day per week regimen. Treatment with 150 mg levamisole on one day per week, with leukocyte count 10 hours after each intake of the drug, undoubtedly appeared to be the most efficient way to prevent agranulocytosis and makes this drug safe in the treatment of RA.


Adverse reactions to the principal drugs used in rheumatoid arthritis--a review. The five basic antirheumatic drugs: antimalarials, immunosuppressive agents, gold salts, penicillamine and levamisole induce side effects in a large number of patients. Some of these are specific to one group of drugs, while others are common to all of them.


[Morbus Hodgkin as a second malignancy in acute lymphoblastic leukaemia (author's transl)]. 19 months after the clinical manifestation of acute lymphoblastic leukaemia, Hodgkin's disease, stage Ia, of the cervical lymphnodes developed in a 10 year old girl during continuous complete remission of leukaemia under chemotherapy. After a regional irradiation and after completing the antileukamic therapy the patient is at present off therapy, healthy and without signs of relapse of both malignant systemic diseases. The coincidence of acute lymphoblastic leukaemia in children with other malignant neoplasias is rare. The expected frequency of second malignancies and the theories concerning oncogenesis are shortly reviewed.


Chromosomal evidence for the transplantability of the Shay chloroleukemia. Chloroma cells, which were shown to contain the X and Y chromosomes, were used to induce Shay chloroleukemia (SCL) in female recipients. Karyotype analyses of leukemic myeloblasts which appeared in the peripheral blood of the female recipients during blast crisis demonstrated invariably the presence of the X and Y chromosomes. These results directly demonstrate that transmission of SCL is the result of donor cell colonization and therefore SCL can be considered a true transplantable leukemia. Reports by other workers of viral association with this disease are discussed in light of our results.


Erythroid cell differentiation.

Erythroid cell differentiation. Normal and transformed erythroid cell precursors provide the opportunity for study of a number of problems relevant to the regulation of proliferation and differentiation in a developmental system. Evidence is presented which suggests that the hormone, erythropoietin, has a primary role in regulating precursor cell proliferation. A wide variety of chemicals can modify the rate at which proliferating transformed precursors initiate expression of the genetic program characteristic of terminal erythroid differentiation. Several sites of inducer action, including the plasma membrane and chromatin, are suggested as part of the pathway which leads to the complex pattern of gene transcription responsible for differentiation.


A reappraisal of the results of stopping therapy in childhood leukemia. We examined the results of stopping therapy in children with acute lymphocytic leukemia. Of 639 patients in eight consecutive "total therapy" studies, 278 (44 per cent) had all treatment stopped, usually after 2 1/2 years of complete remission. About one fifth (55 of 278) of this group have relapsed, mainly in the bone marrow. The relapse rate for the first year off therapy was higher than that for the next three years (0.16 vs. 0.04, P less than 0.01). The life-table estimates of the four-year relapse rates were 0.24 for all patients and 0.22 for patients receiving adequate central-nervous system prophylaxis. Boys had a higher relapse rate than girls (0.33 vs. 0.15 P less than 0.01). None of the 79 patients who remained in complete remission for at least four years off therapy have yet relapsed. Acute lymphocytic leukemia appears curable in over one third of all newly diagnosed patients who receive treatment for approximately 2 1/2 years.


Health care in early infancy.

Health care in early infancy. The pattern of illness and of health care during the first 16 weeks of life in a cohort of 1210 infants was examined. Children from families in the lower social strata had a significantly increased risk of respiratory illness and gastrointestinal disturbance and received less routine well baby care than children from more socially advantaged backgrounds. A number of policy changes which might improve the distribution of health care resources are examined.


A double-blind controlled study of the use of diethylpropion hydrochloride (Tenuate) in obese patients in a rural practice. A double-blind, placebo-controlled, cross-over study has been carried out to compare long-acting diethylpropion hydrochloride (Tenuate Dospan, Wm. S. Merrell Company, hereafter referred to as TD) in a rural general practice. TD was found to produce significantly more weight loss than placebo and side effects were not significantly greater. The need for the treatment of obese patients in general practice is discussed, as is the role of anorexiant therapy.


Asthma: the doctor's failure in communication. Forty-one children with asthma and their parents were interviewed to assess their level of understanding of the disease, drug therapy and prognosis, to define their fears and anxieties and to elucidate the extent to which asthma had interfered with activities and family life. Knowledge of the disease and its natural history was poor, understanding of drug therapy inadequate and anxieties relating to death, separation, permanent lung damage, curtailment of activities were common.


"Precordial catch": a benign syndrome of chest pain in young persons. A common syndrome of brief, sharp, severe precordial pain in 45 healthy young persons is described. The pain occurs at variable intervals, out of the blue. It typically occurs during rest or very mild activity and never on exertion. The onset is usually in adolescence. Most patients were of light or medium build, were nonsmokers and essentially healthy. It affects males and females. Recognition of the syndrome of precordial catch and reassurance of its benign nature will allay anxiety.


Grieving responses: a comparison after home or hospital care. This study, over a five year period in a general practice, has shown that grieving is resolved in a much more desirable way if a dying patient is nursed at home by relatives rather than by strangers in a hospital.


General practitioners and professional satisfaction. One hundred and eighty-five general practitioners participated in a study regarding satisfaction from the doctor-patient relationship. Of these, 71% responded in writing to an open-ended item concerning personal satisfaction. Written responses were assigned to one or more of nine groupings formed by considering the content of general practice and conceptualising characteristics of the doctor-patient relationship. Four characteristics--activity, authority, objectivity and radionality (the clinical model) were assigned 299 written responses. Four characteristics--affinity, continuity, intimacy and reciprocity (the relational model) were assigned 287 responses. The paper discusses the two models, their respective characteristics and physician responses.


The use of ultrasound in threatened abortion. One hundred and twenty-seven pregnancies complicated by painless vaginal bleeding before 20 weeks of gestation were scanned. In the 51 cases where pregnancy continued the scan was normal in 80%. In an additional 10% the only abnormalities were either a low placental implantation or a twin pregnancy, one sac of which was blighted. In another 6% the initial scan was difficult to interpret and a repeat scan was normal. In the remaining 2% an error was made. In the 76 cases where the pregnancy did not continue the scan was abnormal in 83%, there was a low placental implantation but no other abnormality in 4% and in an additional 6.5% a repeat scan was abnormal after an initial normal scan. In the remaining five cases there was one error, abortion occurred probably for obstetrical reasons in three and there was one twin pregnancy where only one sac was abnormal but both were aborted. Ectopic pregnancy was diagnosed in only 33% of cases while molar pregnancy was diagnosed in 75% and in the one which ultrasound failed to diagnose the appearances suggested abortion was inevitable.


Non-vertiginous fluctuating hearing loss. Not all fluctuating hearing loss is due to Eustachian insufficiency. Not all sensorineural loss is untreatable. Fluctuating hearing loss due to endolymphatic hydrops is discussed, and the use of a low sodium diet, diuretics and vasodilators in the treatment of this disorder is described. To be effective, the treatment must be initiated early. Five typical cases are described, showing the typical presentation and response to treatment.


Antistreptococcal antibody titres in the serum of school children in Auckland. Geometric mean titres for serum antistreptococcal antibodies in a group of 12-year-old Auckland children are presented. The mean titres did not change over a period of 12 months in paired samples. The values obtained are similar to published figures from other parts of the world, suggesting the techniques used provide comparable data.


Unilateral breast-feeding: a new clue to the diagnosis of thyrotoxicosis. Two thyrotoxic women who had breast-fed exclusively at the right breast are reported. This phenomenon may prove to be a useful clue to undiagnosed thyrotoxicosis in the postpartum period.


Consulting with parents about children's misbehaviour. This paper summarised a case of a consultant helping a couple to reduce aggressive behaviour in their nine-year-old son. Within a programme of positive reinforcement plus extinction, the parents made the critical decisions about methods and criteria. Comparisons and contrasts were made with another case in which parents were also used as mediators, but were less actively involved in decisions about treatment and outcomes.


Agranulocytosis associated with an infected mandibular fracture. This report describes a case of agranulocytosis associated with an infected mandibular fracture. Because agranulocytosis is most frequently associated with drug sensitivity, drug therapy is usually stopped or changed when the disease is discovered. This case demonstrates the need to evaluate the causes of agranulocytosis before stopping or changing a patient's medications.


Pulsed electromagnetic energy therapy in third molar surgery. Pulsed electromagnetic energy is being increasingly employed to reduced symptoms and enhance the healing process following tissue injury. A double-blind placebo-controlled trial has been carried out to assess the value of electromagnetic energy in third molar surgery, but no significant benefit has been found.


Regional blood flow and collateral circulation of the tongue in the dog studied by hydrogen polarography. Regional lingual blood flow was measured by hydrogen polarography under control conditions and after the subsequent ligation of pertinent arteries in dogs. The results indicate a nonhomogeneous blood supply for the tongue and the existence of a complex collateral circulation in the lingual areas studied.


Giant-cell tumor of the maxilla. Report of a case. Giant-cell tumor of the jaw presents difficulty in diagnosis. It is rare in the head and neck regions and may resemble, clinically and histologically, other types of jaw lesion. However, histologic study may distinguish this lesion from a giant-cell granuloma, an osteogenic sarcoma, and most epulides. Adequate surgical excision with a long-term follow-up is the recommended treatment of choice.


Osteitis deformans. Report of a long-standing case with extensive oral involvement. Presented is a case of osteitis deformans (Paget's disease of bone) with a 38-year history after diagnosis. The patient had nearly the entire spectrum of symptoms that can result from widespread involvement of the skeletal system with this disease. Diffuse involvement of the maxilla and mandible resulted in postextraction complications which are common in Paget's disease of the bone.


Transantral odontoma. A case report.

Transantral odontoma. A case report. Described is the case of a 30-year-old black man with a history of acute pansinusitus, headaches, and intermittent right nasal stuffiness. The history, clinical signs and symptoms, and roentgenographic findings were consistent with the diagnosis of a transantral complex odontoma. Finding of this entity is extremely rare in this region.


Oral mucosal white lesions associated with excessive use of Listerine mouthwash. Report of two cases. Two patients were observed to have asymptomatic, diffuse, filmy white lesions involving large portions of the oral mucosa. Both patients admitted to the topical use of Listerine mouthwash in excess of recommended doses. Other considerations in the differential diagnosis were eliminated by history. The lesions showed complete regression in 2 weeks following discontinuance of the lavage.


Kinky hair disease. Report of a case.

Kinky hair disease. Report of a case. A confirmed case of kinky hair disease is described. Findings include a defect in copper metabolism, peculiar facies, retrognathia, skeletal open-bite, generalized gingival enlargement, and skeletal radiographic abnormalities.


Oral manifestations of chronic granulomatous disease. Chronic granulomatous disease (CGD) has been recognized as a specific entity since 1957. Although a significant number of patients with this inherited disorder of leukocyte function exhibit oral manifestations which might be seen by the dentist, the dental literature contains no descriptions of this disease. The purpose of this article is to present a case of CGD exhibiting oral lesions, to document these lesions clinically and histopathologically, and to discuss the differential diagnosis of this disorder.


The papillary cystadenoma of minor salivary gland origin. This article reviews the literature of the papillary cystadenoma of minor salivary gland origin and discusses and attempts to clarify the true nature of these lesions. The criteria for diagnosis are presented, and classification of this lesion based on the Histological Typing of Salivary Gland Tumours (World Health Organization) is suggested. In addition, an interesting variant, which we have called the papillary cystadenoma, mucous-cell type, is presented.


Cervicofacial actinomycosis following surgical trauma in rats. Cervicofacial actinomycosis in man is often associated with physical trauma. The presence of intrabony abscesses in rat mandibles following surgical trauma supports the clinical observation that antecedent trauma is an important factor in the pathogenesis of cervicofacial actinomycosis.


Dens evaginatus (tuberculated cusps): genetic and treatment considerations. This report documents the occurrence of a rare dental anomaly, dens evaginatus, in several members of a family of Guatemalan Indian descent. Previous reports on this anomaly reveal that the majority of cases have occurred in persons of Mongoloid extraction. These same reports have suggested a genetic component in the etiology of the anomaly, with most cases, however, occurring randomly. This is the first report in which the trait has been reported in successive generations. The precise mechanism of genetic transmission is still not entirely clear, although autosomal dominant inheritance is probable.


Solitary maxillary central incisor and normal stature. Two children, one boy and one girl, each with solitary maxillary deciduous and permanent central incisors, normal height, and normal plasma growth hormone levels, are reported. Review of the literature reveals fourteen reports of patients with a similar dental anomaly. Of these, three are normal in height. The height and growth rate of patients with a single maxillary central incisor should be evaluated prior to growth hormone evaluation; such investigation should be undertaken only if the height is two standard deviations below the mean or if there is evidence of plateauing of linear growth.


Intraoral xeroradiography.

Intraoral xeroradiography. This study compared the diagnostic usefulness of images of dental structures made with two xeroradiographic (XR) processes with those made by conventional radiography. The xerographic systems employed were a Xerox 125 system (designed for mammography) as well as a new experimental xerographic instrument designed for dental use. Structures evaluated included osseous trabecular detail, caries, dental anatomy, soft tissue, and dental restorations. In general, the resolution and detail of these dental structures were noticeably better on conventional films than on the XR 125 images. In addition, the presence of artifacts around the margins of metallic restorations on the XR 125 image severely inhibited detection of recurrent caries. In contrast, XR images formed by the new experimental process were equal to or superior to conventional films in resolving detail of dental struitures. Also, the experimental XR process required less radiation exposure than conventional radiography.


The effect of irradiation on developing teeth. Although the consequences of ionizing irradiation on adult teeth have been adequately described in the literature, there have been few reports concerning the adverse effects on the developing dentition. A case is presented in which the jaws were irradiated at an early age and it was possible to examine some of the abnormal teeth in detail by using clinical, radiographic, and histologic techniques.


Submandibular duct stenosis as a complication of Ludwig's angina. A case of submandibular duct stenosis subsequent to Ludwig's angina is presented. It illustrates the importance of outpatient follow-up after apparent infections.


Occlusal acrylic index used to observe palatal bone cuts. The use of an acrylic occlusal index prior to wiring a full palatal coverage splint into place offers an easy way to check for "hang-up" areas and help in placement of bone grafts while the segments are held in the predetermined position.


Extravasation cyst diagnostic curettement: a treatment. Report of 15 cases and suggested treatment. Fifteen cases of extravasation lesions of the mandible have been treated. In six cases, the lesions were entered surgically, explored, and directly curetted following preliminary diagnosis by needle aspiration. Healing was uneventful in all cases, and bone regeneration occurred rapidly. Hemorrhage was easily controlled, and the surgery was considered a minor procedure. Nine cases were treated by a combined diagnostic-curettement technique. The entire procedure was quickly performed under local anesthesia. There was little chance of injury to surrounding structures, and there were few postoperative sequelae. The resolution of the lesion and bone regeneration occurred in a time span similar to that of the surgical treatment of lesions.


Mucocutaneous lymph node syndrome. Review of a recently described disease complex. Mucocutaneous lymph node syndrome (MLNS) has been accepted in Japan as a newly recognized disease affecting most frequently patients under 5 years of age. It is now apparent that the syndrome, having been defined, is also recognized with increasing frequency in the continental United States and Canada in children of non-Japanese ancestry. MLNS is characterized by (1) fever, (2) bilateral congestion of the conjunctivae, (3) changes in the oral cavity, consisting of strawberry tongue, erythema of the oral mucosa, and sicca of the lips, (4) indurative edema and erythema of the hands and feet followed by desquamation of the fingertips, (5) polymorphous exanthema, and (6) cervical lymphadenopathy. The clinical signs and symptoms are somewhat reminiscent of other related conditions. To prevent potentially fatal cardiac complications associated with MLNS, prompt and accurate diagnosis is imperative so that the patient may be referred to a physician for careful monitoring during convalescence.


Median rhomboid glossitis caused by Candida? The etiology and pathogenesis of median rhomboid glossitis have been subjects of controversial discussions for a long time. In recent years, the possible role of Candida albicans has been stressed. The findings in 18 patients with median rhomboid glossitis only support partly the hypothesis of Candida albicans being an important etiologic factor.


Dental management of leukemic patients.

Dental management of leukemic patients. Three cases involving the oral management of patients with acute leukemia are described. Of particular interest is that the patients had abnormal responses to oral disease, probably related to their compromised host defenses. Because of the difficulty in treating oral disease in leukemic persons while they are undergoing chemotherapy, it is extremely important that such patients have dental evaluations and, if possible, treatment prior to initiation of medical management for their neoplasia.


Minor salivary gland calculi. A clinicopathologic study of forty-seven new cases. An analysis of forty-seven previously unreported cases of minor salivary gland calculi revealed that they were usually solitary, firm, freely movable, small masses. Also, we noted that these calculi exhibited a striking predilection for the upper lip and buccal mucosa of adults. The organic matrix of all calculi was similar; however, the amount of mineralized material was variable. A variety of types of epithelial metaplasia was noted in the pericalcular ducts, with the most common type being squamous-cell metaplasia. Chronic periductal and lobular inflammation in addition to duct ectasia were common findings. The cause of minor salivary gland calculi is not known; however, local factors, such as duct morphology or biochemical alterations, or both, may be involved.


Necrotizing sialometaplasia. A review of the literature and report of two additional cases. Necrotizing sialometaplasia is a nonneoplastic, inflammatory, variably ulcerated, occasionally bilateral, self-healing lesion of human salivary glands which is often confused clinically and histologically with squamous cell or mucoepidermoid carcinoma. On the basis of thirty-three documented cases, the lesion occurs primarily in the minor salivary glands of the palate (87.9 percent), with 63.6 percent arising in the fifth and sixth decades (average age 46.0 years, range 22 to 68 years). There is a marked predilection for males (ratio of males to females. 2.7:1) and a questionable predominance in Caucasians (60.6 percent). Numerous etiologic factors have been proposed; however, on the basis of previous animal experimentation, the lesion appears to be infarctive in nature.


Adult rhabdomyoma of soft palate.

Adult rhabdomyoma of soft palate. A case of adult rhabdomyoma of the soft palate in a 60-year-old man studied by methods including electron microscopy, is reported. The patient was free of recurrence 2 years later. The eleven previously documented cases of adult rhabdomyoma involving the oral cavity are reviewed. The concept that rhabdomyoma is a neoplasm rather than a hamartoma is favored. Adequate local excision appears to be curative. The differences between the cardiac and extracardiac forms of rhabdomyoma as well as between adult rhabdomyoma and especially granular-cell myoblastoma and fetal rhabdomyoma are presented.


Solitary intraoral keratoacanthoma. Report of a case. The keratoacanthoma is a tumorlike proliferation which is rarely seen in the oral cavity. Both clinically and microscopically, it may bear close resemblance to squamous-cell carcinoma. The following article discusses the keratoacanthoma and, in addition, presents a case report of solitary intraoral keratoacanthoma.


Fetal alcohol syndrome.

Fetal alcohol syndrome. A case of fetal alcohol syndrome in an 8-month-old infant is presented. Several of the maxillofacial anomalies associated with this syndrome were present. In addition, a large dentigerous cyst was found, a rare lesion occurring with a deciduous tooth and never before reported in association with fetal alcohol syndrome.


An analysis of the sensitivity of non-rereduced PRS medium in endodontic therapy. A total of 244 paired samples were obtained from sixty-one root canal systems at four specific stages of endodontic treatment. Half the samples were placed in a commonly used endodontic medium and incubated aerobically. The remaining samples were placed in PRS medium and incubated in an anaerobic environment. The rereduction procedure, used to remove oxygen entering the PRS medium at the time of insertion of the sample, was not employed. A statistical analysis of the results indicates that the non-rereduced PRS medium is not as sensitive as rereduced PRS and offers no significant advantages over trypticase soy broth with 0.1 percent agar.


Root canal treatment with calcium hydroxide. I. Effect of overfilling and refilling. Root canals of dog premolar teeth were negotiated and overfilled with calcium hydroxide paste. After 30 days, half of the treated teeth were refilled up to the apical limit. Root canals not filled were considered as the control group. Ninety days after the first treatment, histologic analysis showed more favorable results in the refilled root canals. The overfilling elicits calcium hydroxide resorption and the ingrowth of periapical connective tissue into the root canal.


Root canal treatment with calcium hydroxide. II. Effect of instrumentation beyond the apices. Root canals of dog premolar teeth were instrumented beyond the apices and enlarged up to the size of a No. 40 or 80 file and filled with calcium hydroxide up to the foramen. Ninety days later the histologic data showed more favorable results with the root canals instrumented until file No. 80.


A study of the quality of duplicated radiographs. The resolution, contrast, and clinical appearance of radiographs and duplicate radiographs made with two types of duplicating film were compared. Duplicating conditions evaluated were type and shape of light, light-film distance, type of exposure surface, and developer temperature. Major observations were as follows: both Kodak and DuPont films produced clinically acceptable duplicates; Kodak film was faster; DuPont film responded better in incandescent photoflood light than Kodak film; clear glass with appropriate light-film distance was the best exposure surface.


[Denture cleaning with an enzyme-containing laundry detergent]. An enzyme containing laundry detergent (Rex) was tested as a denture cleanser. It was found more satisfactory than the denture cleansers available on the Norwegian market.


Proton nuclear magnetic resonance characterization of heme disorder in hemoproteins. A proton NMR method is described for determining the orientation of a porphyrin within the heme pocket of a hemoprotein. The pattern of the hyperfine-shifted heme methyl resonances in low-spin ferric model compounds is demonstrated to characteristically reflect the position of a localized low-symmetry perturbation on the pi system. The specific assignments via deuteration of the two interconvertible sets of methyl resonances observed for deuteroporphyrin-reconstituted sperm whale metmyoglobin cyanide lead to the conclusion that the low-symmetry perturbations on the heme due to the apo-protein contacts differ for the two protein components by a 180 degrees rotation about the alpha-gamma meso axis. Hence the heme in the reconstituted myoglobin is "disordered" in solution, and the altered functional properties of the reconstituted protein cannot be simply attributed to the local effect of the heme substituent. This NMR technique has applicability for determining the relative heme orientation in related hemoproteins, and may clarify the origin of doubling of heme resonances observed in several native hemoproteins.


A model for hydration of peptides and its application to the conformational analysis of terminally blocked amino acids and dipeptides. A theoretical model for peptide structure, which takes into account the effects of hydration in conformational energy calculations, is described. The free energy of hydration is composed of a term for "specific hydration," representing solute-water hydrogen bonding, and a term for "non-specific hydration," describing the interaction of the solute with water molecules in a first-neighbor shell. Minimum-energy conformations were computed for the hydrated N-acetyl-N'-methylamides of the 20 naturally occurring amino acids, and the results were compared with those computed in the absence of hydration. The relative energies of many conformations and the width of some low-energy regions of the (ø, Psi) conformational maps are altered when the free energy of nonspecific hydration is included. The term for specific hydration causes large charges of the energy, but only in some regions of the maps. Observed vicinal coupling constants are approximated better by the computation when hydration is included. Conformational preferences of the individual residues in hydrated dipeptides are similar to those computed for the hydrated single residues, showing that intraresidue interactions predominate in dipeptides. This supports the concept of the importance of short-range interactions in proteins. Bend probabilities were computed and compared with observed frequencies of occurrence of bends in proteins of known structure. Computed values improve only for some of the dipeptides containing polar residues or glycine when hydration is included. For bends involving two nonpolar residues, computations omitting hydration give better results.


Chemical synthesis of genes for human insulin. A rapid chemical procedure has been developed and used for the synthesis of 29 oligodeoxyribonucleotides to build synthetic genes for human insulin. The gene for insulin B chain, 104 base pairs, and the one for A chain, 77 base pairs, were designed from the amino acid sequence of human polypeptides. They bear single-stranded cohesive termini for the EcoRI and BamHI restriction endonucleases and are designed to be inserted separately into a pBR322 plasmid. The synthetic fragments, deca- to pentadecanucleotides, were synthesized by a block phosphotriester method with trinucleotides as building blocks. Final purification was by high-performance liquid chromatography. All 29 oligonucleotides were pure and had the correct sequences.


Displacement and aberrant methylation in vitro of H-1 histone in rat liver nuclei after half-saturation of chromatin with polycations. Radiomethyl incorporation in vitro into Nepsilon-methyllysine of histones from rat liver nuclei incubated in the presence of S-adenosyl[methyl-3H]methionine is stimulated if the polycations polylysines, protamines, or histones are added to the incubation mixture. Maximal stimulation occurs at a cation/nucleotide ratio of 0.5. Past this point stimulation drops, except in the case of very lysine-rich histone H-1, for which the maximal level of incorporation remains constant upon further addition of this histone. Bio-Gel P-10 chromatography, differential precipitation, and gel electrophoresis of radiomethylated histones indicate that although the usual incorporation of radiomethyl into histone H-3 is not affected, active methylation of H-1 occurs in the presence of polycations. Column chromatographic amino acid analysis reveals that the methylation of H-1 will specifically generate Nepsilon-monomethyllysine. Except for this condition, H-1 is never methylated in vivo or in incubated cell nuclei. Because H-1 is the weakest bound histone in chromatin, the above phenomena may be explained by assuming that, within the chromatin, polycations displace the lysine-rich histone towards the nucleosome, which results in its abberant methylation, assuming that the native nucleosome is the seat of the histone lysine methyltransferase.


Interaction of bacteriophage lambda repressor with nonoperator DNA containing single-strand gaps. In direct binding assays, purified lambdaind+ repressor displayed high affinity for nonoperator DNA containing single-strand gaps. Its affinity for this same DNA but completely double-stranded, nicked, or denatured was considerably lower. In contrast, purified lambdaind- repressor had 1/10th the affinity for the gapped DNA, a level comparable to that of purified lac repressor. In the presence of limiting amounts of ind+ repressor, nonoperator DNA containing gaps could be shown to compete effectively with lambda DNA for binding of repressor. A previous model of lambda induction [Sussman, R. & Ben-Zeev, H. (1975) Proc. Natl. Acad. Sci. USA 72, 1973--1976], based on the assumption that this phenomenon involves the binding of repressor to lesions in the host DNA, is reevaluated in the light of the data reported here.


Properties of muscarinic acetylcholine receptors in heart cell cultures. The binding of acetylcholine to receptors in the intact heart causes a decrease in the frequency (chronotropic effect) and force (ionotropic effect) of contraction. The studies reported here demonstrate a chronotropic response of cultured embryonic chicken heart cells to the muscarinic agonist carbamoylcholine. This response is markedly decreased after a 3-hr incubation with 0.1 mM carbamoylcholine. In order to determine whether agonist-induced alterations in muscarinic receptors were responsible for this decrease, we studied the effects of incubation with carbamoylcholine on the binding of the (3)H-labeled muscarinic antagonist quinuclidinyl benzilate (QNB) to homogenates of heart cell cultures. [(3)H]QNB binding to homogenates of cultures of embryonic hearts of chicks 9 days in ovo was characterized and shown to have properties similar to those of muscarinic receptors in intact hearts. Binding was both specific and saturable. [(3)H]QNB was displaced by muscarinic agonists and antagonists in concentrations consistent with their known potency. Binding was poorly inhibited by the nicotinic antagonist D-tubocurarine. Kinetic analysis of the binding of QNB by muscarinic receptors showed that initially the reaction proceeds by formation of a rapidly reversible complex with a K(d) of 1.8 nM, which is converted to a slowly reversible form. These properties of muscarinic receptors in heart cell cultures are strikingly similar to those observed in homogenates of intact hearts. Homogenates of heart cell cultures bound 84 +/- 6 fmol (mean +/- SD) of QNB per mg of protein. The number of receptors remained stable from day 4 to day 8 in culture. Incubation of cultures with 0.1 mM carbamoylcholine for 3 hr decreased QNB binding by 55%, to 38 +/- 5 fmol/mg protein. When cell cultures were first homogenized and then incubated with carbamoylcholine, no decrease in QNB binding sites could be detected. Thus, incubation with carbamoylcholine causes loss of muscarinic binding sites as well as decreased physiologic responsiveness to muscarinic agonists.


Change in quantity and size distribution of small circular DNAs during development of chicken bursa. Small circular DNAs ranging in contour length from 0.06 to 3.5 micrometers have been isolated from bursas of 19-day chicken embryos and 4- to 5-week-old chickens. Small circular DNA is present in bursas of 19-day embryos at approximately 0.2 molecules per cell and is very heterogeneous, lacking distinct size classes; most molecules have contour lengths of less than 0.04 micrometers. In contrast, small circular DNA is present in bursas of 4- to 5-week old chickens at about 4 molecules per cell, and although this DNA is still heterogeneous, it contains a major distinct class of molecules 0.8 micrometers in size. These small circular DNAs may be products of developmental gene rearrangements occurring in the chromosomal DNA of lymphocytes in the bursa.