Patterns of sugar consumption in early infancy.

A study is described in which patterns of sugar consumption in early infancy have been investigated in a rural area in Britain. A representative group of 94 mothers of first babies aged 8-11 months answered questions on the introduction of various foods and drinks containing sugar to their babies' diet. A diet sheet was completed in order to estimate the frequency of sugar consumption on the previous day for both the mother and her child. The findings show that babies received sweet items on an average of 4.3 separate occasions and that 77% of the meals and snacks given to babies contained sugar. The study describes some of the specific ways which sugar is first introduced and concludes that the frequency of sugar consumption is high, even in the 1st year of life.


Changes of dental treatment pattern in Norway in the 1970s.

With the aim of gauging utilization rates of dental services, a series of cross-sectional studies were performed in 1973, 1975 adnd 1977. Cluster samples of 1,600 individuals covering the Norwegian population aged 15 and above were interviewed by trained interviewers using standardized questions. The percentage of respondents who reported having seen a dentist within the last 12 months increased from 58 to 64. The receipt of tooth fillings was the predominant course of treatment and was reported by 55% of the interviewees. The percentage reporting preventive services increased from 15 to 26% at the expense of those reporting "blood and vulcanite" denistry. Fifty-two percent, increasing to 53% of the interviewers, claimed to have seen a dentist on a regular basis during the last 5 years. However, this proportion was conceivably overreported. Control questions indicated that 40-45% should be considered regular treatment attenders. Change is apparently taking place in the treatment pattern. The proportion of regular treatment attenders seems to increase by 0.5-1% per year. The treatment profile is also shifting: extractions and denture services are diminishing, preventive services are gaining, while restorative dentistry stands still - for the time being.


Survey of state funds available for rehabilitation of patients with cleft lip/palate.

An effort was made to determine the amount of funds budgeted in each of the 50 U.S. states for total rehabilitation of patients with cleft lip and/or cleft palate. Questionnaires were sent following a pilot letter to the directors of each state Department of Health. Total funds per patient ranged from $17,442 for Delaware to a low of $426 for Wisconsin. Dental funds per patient ranged from $4,214 dollars for Wyoming to a low of $192 for New York.


The ultrastructure of human osteosarcoma: a study of nine cases.

Electron microscopic study of 9 osteosarcomas corroborates the light microscopic observation that cells with osteoblastic, chondroblastic and fibroblastic features occur in osteosarcomas. Two types of multinucleated giant cells were observed, one was osteoclast-like. The other had anaplastic and degenerative changes. The intercellular matrix is composed of collagen fibers, amorphous ground substance with osteoid and tumor bone. Contrary to many previous electron microscopic reports, osteosarcomas contain more than one cell type.


Evaluation of quandrant dentistry in provision of dental care.

The chairtime required for a single Class I or Class II amalgam restoration at 163 sittings was compared with the chairtime required for 99 cases in which two restorations in a quandrant were treated at the same sitting. The "Quadrant Dentistry Efficiency Rate" was calculated and it was found that quadrant dentistry resulted in a saving of between 30% and 50% of chairtime. The individual speed of the three dentists treating the children did not greatly influence the percentage of chairtime saved.


An epidemiologic survey of periodontal disease in Dutch adults.

An epidemiologic survey was carried out to assess the prevalence and severity of periodontal disease in randomly selected samples of employed populations in the Netherlands. Of the 1,337 persons examined by five examiners, 19.8% were edentulous; 61% of dentate persons had intense gingivitis in an average of 2.4 segments of their mouths; 53% had pockets of 3-6 mm and a further 10.1% had pockets of greater than 6 mm. The prevalence of gingivitis and pocketing increased with increasing age and decreasing levels of education. As no measures of predicting compliance were used and because treatment philosophies differ, no reasonable assessment of treatment needs could be made.


Dental health in a group of Swedish 8-year-olds followed since the age of 3.

A study was made of the dental health of a group of 8-year-old children studied earlier as 3-, 4- and 5-year-olds, including examination of caries, gingivitis and occlusion, as well as certain data on oral habits and fluoride prophylaxis. Caries was found in 92% of the children. The mean DMFS-value was 3.1 and the mean defs-value 8.8. A statistically significant correlation was demonstrated between caries indices at 3 and 8 years of age in the group as a whole. Children with a defs-value higher than the mean defs-value at the age of 3, had a higher mean DMFS-value at the age of 8 than the rest of the group. Sagittal relationships remained largely unchanged between 3 and 8 years of age, while the number of children with an anterior open bite decreased from 51% to 4% during the same time, probably due to a decrease in sucking habits.


Dental caries in South African white children aged 1-5 years.

The dentitions of 499 white preschoolchildren aged 1-5 years from a low fluoride area were examined with mirror and probe. The dmft values ranged from 1.0 +/- 2.0 at 1 year of age to 5.1 +/- 4.5 at 5 years of age while the overall mean for the group was 3.7 +/- 4.1. ""Rampant" caries prevalence varied according to the definition used. It is suggested that for epidemiologic studies rampant caries should be defined as a dmft value of 5 or more and that labial caries should be regarded as a specific entity.


Periodontal disease and oral hygiene in Israeli youth (14-17 years of age).

The purpose of the pesent study was to obtain current information regarding periodontal disease and oral hygiene status. The survey was conducted in Israel amon 9th-12th grade students, 14-17 years of age. A total of 1,320 schoolchildren were examined. During the examination only periodontal status and oral hygiene were checked. Periodontal status was recorded according to Russell's Periodontal Index (PI). Oral cleanliness was assessed according to GREENE & VERMILLION'S Simplified Oral Hygiene Index (OHI-S). The mean PI found was 0.22. The results indicated an increase in the mean PI with age. No difference was found in average PI values between girls and boys. On the other hand, significantly lower mean OHI-S values were recorded for girls as compared with boys in the total study population and within the different age groups. Mean OHI-S decreased with age, indicating improvement.


Prevalence of dental caries and quality of restorations among new immigrants to Israel.

The purpose of the present investigation was to gather information on the prevalence of dental caries and the quality of restorations of new immigrants to Israel, and to compare those two categories among immigrants from different regions of origin. New immigrants, residents of four absorption centers in Israel, were included in the study. Altogether, 1,031 immigrants (417 Eastern European, 338 Western European/North American and 276 South American) were examined. The results indicate that new immigrants to Israel from Eastern Europe are affected with more carious teeth (D), are missing more teeth (M), and have received quantitatively less treatment (F) than immigrants from Western Europe/North American and South America. The South America are an intermediate group. A similar distribution was found between the groups by their respective ages. The quality of dental restoration was found to be statistically higher among immigrants from Western European/North American and South American origins with the latter group exhibiting an intermediate level of quality of dental restorations.


Epidemiology of dental caries in 5-year-old children in Israel.

The objective of this study was to assess the prevalence of dental caries in the earliest age at which children were organized as a group in the national education system and to find possible associations with variables that may help to identify "groups at risk" in this population. A total of 965 children, 5 years old, were examined. They were selected by a method to form a representative sample of all West Jerusalem compulsory kindergarten classes in 1971. Caries, gingivitis and oral hygiene were assessed and demogrphic data were collected. It was found that 84% of the children were affected with mean dif value of 4.7 (+/- 3.6). Association was found between caries and social class. The high morbidity suggests that organized services should be planned for this age group. Since the resources are limited, efforts should be directed mainly towards "groups at risk".


Actual caries development compared with expected caries activity.

In 18 schoolboys, 16 years old, the actual caries development during 1 year was compared with the expected caries activity which was predicted from evaluations of four selected tests: (1) the buffer capacity, (2) the titer of Streptococcus mutans in stimulated whole saliva, (3) clinical evaluation of rate of plaque formation, and (4) a quantitation of a salivary agglutinin reacting with a serotype c strain of S. mutans. According to previous experiences the estimated value for each factor was classified for each individual either as a negative (carries-provoking) or as a non-negative factor. The score of negative factors could thus vary between 0 and 4 for each individual. A good relationship was observed between the caries increment during 1 year and the sum of the scores from the tests representing expected caries activity. This observation indicates the possibility of selecting the most caries susceptible individuals in a population by using the four parameters. A selection can be made from two or three of the tests but then the degree of differentiation becomes lower. No parameter could singly be used as an indication of the potential caries activity in the individual test.


Skin manifestations of leukemias and lymphomas.

The diseases discussed in this paper include chronic lymphocytic leukemia, monocytic leukemia, chronic granulocytic leukemia, acute leukemias, Hodgkin's disease, and lymphosarcoma. Cutaneous manifestations of these disorders are often sufficiently different to indicate a certain leukemia or lymphoma. The cutaneous manifestations of leukemias and lymphomas may help the clinician suspect the diagnosis.


[Suggestions for endosseous implantations from a prosthetic viewpoint].

It is suggested that intra-osseous implants should not be evaluated on the basis of "difficult cases", but by finding out whether there are indications for its preferential use in competition with usual prosthetic materials and methods.


[Comparative light and scanning electron microscopic studies of the human gingiva by means of the filter imprint method].

The structure of the mucosal surface can be reproduced almost unchanged by the filter imprint method. Scan electronmicroscopic investigations of the tissue surface and the surface cells removed by the imprint technique demonstrate that only the uppermost cell layer is removed and that these cells retain their layer distribution, form and fine surface structure. It is therefore possible to describe the cells in the print morphologically by light microscopy and to characterize them functionally by differential staining.


[Effect of oxygen and humidity on UV-polymerizable sealing materials].

The influence of humidity, oxygen and protecting gases on the wetting capacity of UV polymerisable adhesives is examined by means of border-angle measurements. The thickness of the upper layer not polymerisable through the presence of oxygen is determined and its effect on the surface structure of compounds is clarified by scanning electron microsc-investigations. For solution the use of a protecting gas is discussed.


[The adhesion of sealants to dental enamel].

The test product VM 4 of the Kulzer company, Bad Homburg v.d.H., was tested and compared with the commercial products Nuva Seal, Enamelite, and Palakav. Extracted and sealed teeth were kept in water at 37 degrees C for 67 days and subsequently the adhesive strength between dental surface and sealant was tested in tensile strength tests.


[The static (latent) bone cavity. A contribution of 3 cases to the unknown etiology].

During one year 3 patients with static (latent) bone cavities were observed in the Clinic and Policlinic for maxil-lofacial surgery of the University of Münich. The findings are compared with reports from the literature and possible causes are discussed.


[Appearance and diagnosis of odontomas].

Odontomata are relatively seldom encountered. The diagnosis is made accidentally or from abnormal findings such as persistance of a milk tooth, disturbances in tooth eruption, diastema and others. Localisation is established by X-ray.


[Parotid and submandibular gland aplasia with atresia of the lacrimal canaliculi].

A genesis of the large salivary glands is rare. Aetiology and pathogenesis of the non-formation of these glands is uncertain. On account of marked xerostomia this non-formation is of special significance for preventive dental measures.


[Comparative studies on the plaque forming effect of sorbitol and saccharose containing chocolate].

Dental plaque values determined immediately after consuming Sorbitol-containing chocolates were significantly lower than those after consuming Saccharose containing chocolate. These data support indirectly the results of clinical experiments concerning the reduced cariogenicity of Sorbitol-containing sweets.


[Spatial variations of the mechanical properties of dental enamel and dentin].

Cuts with a Vickers diamond were made in five horizontal planes of the upper third of the crown of human lower premolars. At the same time the depth of entry was registered directly during the cutting with adot screen with a distance of about 150 mu between the dots. The depth of the cuts obtained was determined by optical measurement of breadth. Only in the fissure enamel was a slight hardening in the cervical direction observed. With a 5 p loading of the cutter diamond the reversible (elastic) deformation in the dentine is 0,4 +/- 0,1 micrometer greater than in the enamel. The optically determined cutting depth (irreversible deformation) amounted to 1,2 +/- 0,1 micrometer or 2,1 +/- 0,2 micrometer in enamel and dentine.


[Problems of an infectious jaw cyst in the mixed dentition. Case report].

The article describes the complicated treatment of a jaw cyst, caused by an infected temporary tooth. The genesis and the clinical characteristics of jaw cysts in young patients, as well as the importance of due time extraction of the strongly ruined temporary teeth is discussed.


[Effect of radioprotectars from various chemical compound classes on dynamic work capacity and carbohydrate metabolism].

The influence of radioprotectors cystamine, mexamine and gammaphos on the physical performance capacity and carbohydrate metabolism was subjected to a comparative study. Cystamine and mexamine were found to lower the capacity of the animals to endure physical loads, this being attended by falling stocks of glycogen in the liver and muscles and a rising level of the blood lactate and pyruvate in comparison with controls. Gammaphos has no effect on the performance capacity of the animals and carbohydrate metabolism.


[Physiological and pathophysiological investigations on neuronal mechanisms of locomotion in the cats (author's transl)].

Electromyographic investigation was carried out on the cats in order to analyse the neuronal mechanisms of locomotive movements. 1. When normal unrestrained cats walked gastrocnemius muscle, an extensor, began the activities 77.4 +/- 12.1 msec prior the stance phase. This evidence shows that locomotive movement is preprogrammed in the central nervous system. 2. When hemisection was applied to the spinal cord, reciprocal activities in the antagonistic muscles disappeared for several days. However, the reciprocity resumed again eventually. 3. When two hemisections on both sides were applied at different levels of the spinal cord at intervals of more than 30 days, the cat could not stand for 20-30 days after the second hemisection, but eventually could stand. The reciprocity between the antagonistic muscles were greatly disturbed in many cases. 4. In several cases placing reaction could not be elicited in the two hemisected cats. The possible roles of descending tracts in locomotion were discussed.


On estimating number of genes by genotype assay.

The method of genotype assay, proposed by Jinks and Towey (1976) for estimating the number of effective factors in a polygenic system, assumes independent segregation if applied to number of genes. Their results are extended to include the case of linked genes, and the ratio of expected number of effective factors to number of genes is computed for a range of models. Unless all genes are on different chromosomes or many generations of inbreeding are used, the estimate of gene number is biased downwards.


Inducers of erythroleukemic differentiation. Relationship of structure to activity among planar-polar compounds.

Hexamethylenebisacetamide is a potent inducer of erythroid differentiation in murine erythroleukemia cells. A series of chemical compounds structurally related to hexamethylenebisacetamide were tested for inducing activity including polymethylene chains terminally substituted with various combinations of carboxylate, amino, amide, or sulfoxide groups. Effective "dimerization" of dimethyl sulfoxide through a linear polymethylene chain increases its inducing activity by a magnitude similar to that observed when N-methylacetamide is effectively dimerized in such a manner. It was found that all potent inducing agents possess both a hydrophilic and hydrophobic portion of the molecule, as well as a planar portion. All are Lewis bases, possessing a free electron pair available for hydrogen bonding. The polymethylene chain joining functional groups must be flexible and must be 5 to 6 carbon atoms in length to achieve maximal activity. Introduction of triple or double (cis or trans) bonds into the polymethylene chain does not alter activity.


Development of bacterial plaque in the oral cavity.

Dental plaque may be defined as bacterial aggregations upon the teeth and other solid structures inserted in the oral cavity. It is formed by oral microorganisms which attach to the teeth in sheltered areas along the gingival margin, on the approximal surfaces, and in pits and fissures on the masticatory surfaces. The plaque increases in quantity either by multiplication of already attached organisms, or by continuous addition to the deposits of bacteria from the saliva. Structural analyses indicate that the organisms are held together in an exracellular matrix partly produced by the organisms and partly derived from saliva. The microflora of plaque is complex and shows great individual variation. There are also characteristic differences in plaque from different sites on the teeth. Thus dento-gingival plaque is qualitatively different from that of the occlusal fissures. Furthermore, the relative proportion of different types of microorganisms may vary with the age of the deposit. Such information must be taken in consideration when attempts are made to develop chemical agents for the purpose of inhibiting plaque formation in order to prevent periodontal disease and caries.


Use of Hibitane following periodontal surgery.

A number of studies have assessed the effect of chlorhexidine on the postoperative healing of periodontal wounds. Available data suggest that rinsing with a 0.2% chlorhexidine gluconate solution does not influence healing while a conventional dressing is in place, but once this is removed healing is enhanced by either a chlorhexidine rinse or gel. Dressings incorporating chlorhexidine also hasten wound healing. Studies undertaken in dogs clearly demonstrate that the beneficial effect of this agent is due to its ability to remove existing plaque deposits and prevent new plaque formation.


Safety of Hibitane. I. Laboratory experiments.

The safety evaluation of chlorhexidine (Hibitane) in animal species will be briefly reviewed. The relevance of these studies to human use will be discussed, and species comparisons made where possible. Animal studies with chlorhexidine were begun more than two decades ago and the evaluation of its safety has been under continual review ever since. Chlorhexidine is poorly absorbed after oral administration, well tolerated after parenteral administration and its percutaneous absorption is abolutely minimal. No clinical or histological effects have been obtained in any animal study to cause hesitation in the light of proliferating applications of chlorhexidine in human use. The various toxicological studies in animals will be described and in particular the results of a 2-year study in rats will be outlined. In this, as an in earlier long-term study, there were no effects whatsoever to suggest that chlorhexidine treatment could give rise to any kind of tumourigenic effect or any other toxic sign.


Safety of Hibitane. II. Human experience.

Chlorhexidine has been widely used in medical practice since its introduction on to the marked in the early 1950s. Primarily it has been used for topical antisepsis, e.g. pre-surgery skin preparation, burns prophylaxis, and prior to obstetrical/gynaecological procedures. This extensive experience has demonstrated the virtual absence of sensitization and a low irritancy potential for the compound. Only one significant adverse effect has been identified during medical use, namely, the production of sensorineural deafness after direct instillation into the middle ear, a property shared by several commonly used antiseptics. The encouraging reports of the use of chlorhexidine for plaque control prompted further safety investigations. It has been shown that absorption after oral ingestion is very low, and long-term oral use has not produced changes in haematological and biochemical parameters. Occasional oral intolerance of mouthrinse formulations has been reported, although no histological abnormalities were present in gingival biopsies taken after 18 months' daily use. Very occasionally, a reversible swelling of the parotid glands has been reported after use of chlorhexidine in mouthrinse formulations, but not after other methods of administration. Tooth discoloration, which shows wide inter-individual variation is seen after all dental formulations. This undesirable cosmetic effect would appear to represent the only significant argument against everyday prophylactic oral use of chlorhexidine.


Autologous tooth transplantation to replace molars lost in patients with juvenile periodontitis.

A method is described to replace perodontally destroyed first molars in patients with juvenile periodontitis by auto-transplantation of third molars. Fifteen molars which had been extracted due to periodontal destruction were replaced by autologous third molars with incomplete root formation. The patients were then observed for a period up to 7 years. In all cases complete regeneration of the alveolar bone took place and radiographically a normal periodontal membrane was extablished. All of the transplanted teeth continued their root formation and there was no radiographic evidence for root resorption, ankylosis or necrosis of the pulp. None of the transplanted teeth displayed pocket depths over 3 mm and no abnormal mobility was detectable.


A four-year longitudinal study of the impact on learning structure on dental student lifestyle values.

Acquiring values is an important part in the education of dental students. This study describes how the values of 109 dental students changed over four years in the dental school's learning environment. Data describe the dental school learning environment as highly teacher-centered, in which authority is vested in faculty, in which activities are highly programmed, and in which communication is one-way, teacher-to-student. The data also indicate significant changes in dental students' values after four years in this environment. Learning from and sharing with others, interpersonal communication, and close relationships with others are valued less by students while more value is placed on their own interests and goals.


A survey of patient and auxiliary problems as they relate to behavioral dentistry curricula.

The attempt to prepare students to manage problems in their dental practices must be preceded by precise identification of specific problems. The purpose of this study was to identify such problems. A random sample of practicing dentists cited collecting fees, poor patient motivation, patient fear, and broken or cancelled appointments as their most commonly encountered patient problems. The most commonly cited auxiliary problems were retraining auxiliary personnel and poor motivation. The dentists gave support to courses addressing these topics in the third and fourth years of the dental curriculum. The survey supports the increasing emphasis on behavioral dentistry curricula and identifies the most relevant topics for such courses.


Cardiopulmonary resuscitation training in american dental schools and requirement for state licensure.

A questionnaire was sent to every American dental school and each state and regional testing agency, requesting information on the teaching of basic cardiopulmonary resuscitation (BCPR) and its inclusion in the requirements for state dental licensure. The data indicates that 81 percent of the schools teach a course in BCPR and the remaining 19 percent may do so in the future. Presently, 5 states require certification in BCPR for licensure and 17 states indicated they will require BCPR certification shortly.


A progress report on six year's experience with a flexible, modular dental curriculum.

A flexible, modular curriculum, using self-instructional teaching packages, was implemented in 1972 with the first class of students at the University of Florida College of Dentistry. With only minor modifications in design, this program has been utilized continuously since that time. A reaction to the preconceived advantages and disadvantages of this system is presented. In general, the program has been well received, and is considered a feasible and appropriate approach to dental education.


Dental clinical evaluation: a review of the research.

Preclinical and clinical evaluation in dental education needs systematic study. Research on the main variables affecting reliable and valid clinical evaluation is reviewed to identify research findings applicable to clinical evaluation settings. The research reviewed shows that performance criteria should be objectively stated, that measurement scales should contain few points, and that evaluator training may improve reliability. Suggestions for the design of future evaluation studies are provided in an effort to expand the scope and usefulness of this type of research.


The University of Rochester predental program: finding and motivating potential dental students.

While many dental schools have cooperative programs with various undergraduate schools, the University of Rochester has developed a unique program that emphasizes dental career opportunities and demonstrates how dental research relates to other disciplines. Through active participation in research, predental students become more highly motivated and appreciate more fully the relationship of dentistry to other aspects of health care. Dental schools benefit from such a predental program in that they are presented with a more complete picture of the dental school candidate. In addition to his grades and biographical data, they have an indication of his interests, his creativity and how well he functions in a research environment.


Metastatic tumors of the hand: a report of six cases.

Six metastatic tumors of the hand of mammary, renal, pulmonary, colonic, and humeral origins are described. The areas involved were the distal phalanges, the metacarpal bones, a carpal bone, the nail bed, and the soft tissue of the dorsum of the hand. All six patients died within a few months after the metastatic lesions were diagnosed correctly. Metastases to the bone can cause destruction, pain, and swelling and may be misdiagnosed before operation as osteomyelitis. Metastases to the soft tissues tend to be asymptomatic and can closely mimic benign soft tissue tumors.


Membranes from a transplantable osteogenic sarcoma responsive to parathyroid hormone and prostaglandins: regulation of adenylate cyclase and of hormone metabolism.

Adenylate cyclase activity in particulate fractions from a transplantable rat osteogenic sarcoma was stimulated in a dose-dependent manner by prostaglandins E1 and E2 (PGE1 and PGE2) and parathyroid hormone (PTH). Prostaglandin F2alpha was active at a high concentration (3 x 10(-4) mol/l). Pretreatment of membranes with collagenase plus hyaluronidase reduced the magnitude of the PTH effect but did not affect the size of the PGE1 effect. Guanosine 5'-triphosphate and its synthetic analogue 5'-guanylylimidodiphosphate (Gpp(NH)p) activated adenylate cyclase in particulate preparations from the osteogenic sarcoma. The latter agent produced much larger effects, although the concentrations required for half-maximal enzyme activation were the same for both agonists (approximately 2 x 10(-6) mol/l). The effects of PTH and Gpp(NH)p were supra-additive at some concentrations of hormone. The effects of PGE1 and Gpp(NH)p were supra-additive at all hormone concentrations tested. Pre-incubation of membrane particles for 6 min with PTH produced an enzyme activation which was not reversed by dilution through washing; pre-incubation with PGE1 did not produce this effect. The response of membrane adenylate cyclase to Gpp(NH)p (10(-4) mol/l) was 75% greater in preparations pre-incubated with PTH than in membranes pre-incubated in buffer alone or in buffer containing PGE1. The basal rate of cyclic AMP production in the  adenylate cyclase assay system decreased over a 35 min incubation period. This decrease was prevented by addition of PTH or PGE1. Addition of NaF or Gpp(NH)p produced a steady increase in the rate of production of cyclic AMP with time. Membrane preparations did not reduce the biological activity of PTH and did not degrade 125I-labelled PTH. The results demonstrate that the PTH- and PGE-responsive adenylate cyclases of the osteogenic sarcoma have distinctly different properties and that particulate preparations of the tumour do not metabolize PTH.


Management of severe cerebral edema in the metabolic encephalopathy of Reye-Johnson syndrome.

Fifteen critically ill children with the diagnosis of Reye-Johnson syndrome were treated with techniques developed to maintain adequate cerebral perfusion pressure and levels of circulating blood glucose. One child died, three sustained neurological deficit, and nine children (70%) recovered without significant neurological dysfunction. The technique developed during the period these children were treated, the indications for their use, and factors that can interfere with maintaining adequate cerebral perfusion in patients with increased intracranial pressure from metabolic encephalopathy are described. The results suggest that neurological damage in this syndrome results from neuronal injury secondary to inadequate cerebral perfusion and/or hypoglycemia, and that neurological dysfunction like hepatic dysfunction should produce minimal mortality and morbidity if cerebral perfusion and adequate levels of circulating blood glucose are sustained during the period of increased intracranial pressure and liver failure.


Determination of N,N-dimethylindolealkylamines in plasma, blood and urine extracts by radioimmunoassay and high pressure liquid chromatography.

A sensitive radioimmunoassay for N,N-dimethylindolealkylamine derivatives has been developed. It is possible to detect 200 to 700 femtomoles of 5-hydroxy-N,N-dimethyltryptamine, 5-methoxy-N,N-dimethyltryptamine or N,N-dimethyltryptamine in a given sample. Antibodies were produced in rabbits immunized with a conjugate prepared by reacting 5-hydroxy-N,N-dimethyltryptamine with a diazotized dl-p-amino-phenylalanine bovine serum albumin conjugate. For identification of immunoreactive material high pressure liquid chromatography was used to separate these compounds from each other and from known cross-reacting compounds found in physiological specimens. After chromatography, individual fractions were analyzed by the radioimmunoassay. This combination of high pressure liquid chromatography and radioimmunoassay has permitted the identification and quantification of these compounds in extracts of urine, plasma and whole blood from normal individuals.


Acute leukemia following cyclophosphamide therapy for Sjögren's syndrome.

A fatal myeloproliferative syndrome diagnosed as subacute myelomonocytic leukemia developed in a patient with Sjögren's syndrome following treatment with cyclophosphamide. Although patients with Sjögren's syndrome have a recognized increased risk of developing lymphoproliferative disorders, particularly reticulum cell sarcoma, there is no evidence to support a similar predisposition to leukemia. As immunosuppressive therapy is becoming more common in the treatment of patients with rheumatoid arthritis, there have been recent reports of patients developing fatal myeloproliferative disorders after receiving immunosuppressive therapy. Review of these cases shows similar duration of therapy, and cyclophosphamide, among others, has been implicated as the leukemogenic agent in other patients. We feel that great caution should be exercised in the use of immunosuppressive drugs in patients with chronic, nonfatal disorders sich as rheumatoid arthritis and Sjögren's syndrome.


Adult acute lymphoblastic leukaemia: a five-year experience.

The case histories of all patients for whom the diagnosis of acute lymphoblastic leukaemia (ALL) was made over a five-year period at the Royal Adelaide Hospital and Institute of Medical and Veterinary Science were studied. There were 34 patients with a median age of 47.5 years. Adequate follow-up was obtained on 33 patients, and their median survival was 5.4 months. The remission rate was 77% in the under-30 years age group, but only 15% in the over-30 years age group. The median duration of remission was 24 months while the median survival of remitters has not yet been reached. The median survival of non-remitters was two months with 100% being dead at 12-3 months. Of 20 patients without remission, seven died of haemorrhage and/or infection before an adequate trial of therapy had been completed, while nine patients had "adequate" intensive therapy but failed to achieve remission.


Positive monospot tests preceding the diagnosis of acute monocytic leukemia in two adolescents.

The early detection and treatment of two cases of acute monocytic leukemia (AMoL) was hampered by the presence of positive slide tests for infectious mononucleosis (IM). This assumes great importance with the recent development of specific therapy, effective for certain subtypes of nonlymphocytic leukemia.


Cis-diamminedichloroplatinum (NSC-119875) in childhood malignancies: a Southwest Oncology Group study.

Children with malignancies resistant to conventional therapy were treated with cis-diamminedichloroplatinum (PDD), 15 to 20 mg/m2, given daily by rapid intravenous infusion for 5 days at 3-wk intervals. Eleven of 24 children with acute lymphocytic leukemia (ALL) received two or more courses; among these no remissions occurred. Fifty-four children with solid tumors were treated: 25 neuroblastoma, 9 rhabdomyosarcoma, 4 Ewing sarcoma, 2 testicular embryonal carcinoma, 2 retinoblastoma, and 12 miscellaneous tumors. One complete remission, 3 partial remissions, and 2 improvements were observed in children with neuroblastoma. One girl with metastatic osteogenic sarcoma achieved a partial remission. One child with metastatic testicular embryonal carcinoma showed improvement. The side effects were vomiting controlled by antiemetics in 26 children and transient elevations of serum creatinine and BUN in 14 children. Nineteen of 39 children with solid tumors, who received more than one course of PDD, had moderately severe myelosuppression caused by PDD. In summary, PDD is a promising agent in neuroblastoma, osteogenic sarcoma, and testicular embryonal carcinoma, and an ineffective agent in ALL. The effect of PDD on other types of solid tumors should be evaluated in the future.


Blastic transformation in chronic myelogenous leukemia: experience with 50 patients.

Fifty consecutive patients with blastic chronic myelogenous leukemia were evaluated clinically, morphologically, biochemically, and therapeutically. Forty-five patients had a preceding stable phase (38 Ph'+, 7 Ph'-); five patients presented with de novo Ph+ blast crisis. The most frequent clinical signs of impending blast crisis were weakness, fatigue, increasing splenomegaly, anemia, thrombocytopenia, marrow fibrosis, and a rising neutrophil alkaline phosphatase. Fever (unrelated to infection), skin infiltration, lymphadenopathy, hepatomegaly, thrombocytosis, and basophilia were much less common. The development of aneuploidy occurred in less than one-half of the total group. Myeloblastic morphology at blastic transformation was most frequent with occasional lymphoblastic, promyelocytic, and undifferentiated cases seen. Terminal deoxynucleotidyl transferase was present in one-third of the patients, but had no clear-cut relationship to the morphology. Response to treatment was generally disappointing (two complete and 15 partial remissions in 45 treated patients).


Repeated use of L-asparaginase in multi-drug therapy of childhood leukemia.

The capacity of 1-asparaginase in two separate schedules (consecutive and intermittent), along with vincristine and prednisone to produce multiple responses, was evaluated in previously treated children with acute leukemia in relapse. The response rates varied inversely with previous 1-asparaginase exposure. A history of prior resistance to prednisone and vincristine appeared to reduce the response rate. Hypersensitivity reactions occurred in 14%.


[So-called Pindborg's tumor: calcifying odontogenic epithelial tumor].

A case of Pindborg's tumour or calcifying odontogenous epithelial tumour in the included +3 of a young girl is presented. The histogenetic explanation given by the first workers to the earliest cases--origin in residues of the enamel organic matrix--is accepted as the most probable, though it is pointed out that the small number of reported cases make doubt and uncertainty inevitable. An interesting point about the case is that its clinical course was followed for several years after surgery.


[Fractures of the orbito-zygomatico-malar complex].

Reference is made to the increasing number and severity of orbito-zygomatico-malar fractures brought about by the greater number of vehicles on the orads and their higher speeds. Fracture lines in such cases very considerably. An account is given of the therapeutical approaches usually followed at the Parma University Odontostomatological Clinic, based on experience acquired in 275 cases.


Progress of infants fed Karitane Milk Food compared with those on breast or homogenised milk.

A study was made of three groups of babies, one breast fed, one having Karitane Milk Food, the third homogenised milk. Blood sodium and urea were measured in the neonatal period. The urea levels were significantly higher in babies having homogenised milk compared with those fed Karitane or breast milk. Haemoglobin was measured in the neonatal period, and at 3, 6, 10 1/2 and 18 months. At six months, haemoglobin levels were significantly higher in Karitane milk fed than in homogenised milk fed babies. Serum cholesterol and triglyceride were measured in cord blood, and at 6 and 18 months of age. Serum triglyceride levels in babies on Karitane Milk Food were significantly higher than those on homogenised milk. Increments in weight, height and head circumference were compared. Karitane milk fed babies gained significantly more weight than breast fed between three and six months of age.


Cardiac rhythm problems in subarachnoid haemorrhage: report of two patients.

Two patients were admitted with the provisional diagnosis of ischaemic heart disease. Both patients had lumbar punctures and the final diagnosis of subarachnoid haemorrhage with complicating cardiac arrhythmias was made in both cases.


A two year follow-up of a hypertension screening programme Napier 1973-1975.

Two years after a hypertension screening survey conducted at Napier in 1973 the blood pressure levels of 350 adults were re-examined. The sample comprised 152 persons previously referred for investigation because of high blood pressure detected during the 1973 survey, a matched control group of 146 normotensives and a small supplementary control group. Of the 152 persons in the referred group 31 (20.4%) were under medical supervision at the time of the 1973 survey, 89 (58.5%) attended a doctor within the next 12 months and 32 (21.1%) took no further action. Two years later the 31 cases previously under medical supervision had remained on therapy but only 43 of the 89 new cases were receiving treatment at the time of re-examination. More than 50% of the cases in the referred group showed a decrease in the mean systolic pressure of 10mmHg or greater over the two-year period compared with 20.5% of the normotensive control group. Only 32% of referred cases were regarded as effectively controlled at the time of re-examination ie had mean systolic pressures less than 160mmHg and mean diastolic pressures less than 95mmHg. The low level of effective control resulting from the earlier survey casts further doubt on the value of mass screening procedures for hypertension.


Cigarette smoking habits, attitudes and associated social factors in adolescents.

Cigarette smoking habits and attitudes and associated social factors of 997 third and fourth form pupils were studied, using an interviewer administered questionnaire, in two co-educational secondary schools as part of a smoking intervention programme. Overall, 32 percent of the pupils were regular smokers with 15% smoking more than two cigarettes per day. The majority of smokers began smoking before secondary school; boys started earlier than girls,nd heavy smokers earlier than light smokers. The commonest reason for giving up smoking was personal dislike. Heavy smokers were more likely to have respiratory symptoms than other pupils. The smoking habits of the pupils were related to those of their parents, siblings and friends. The majority of pupils thought cigarette smoking bad for their health irrespective of their own smoking habits.


Poisoning, burns, and other accidents experienced by a thousand Dunedin three year olds: a report from the Dunedin multidisciplinary child development study.

Poisoning, burns, and other accidents experienced by 1037 Dunedin children during their first three years of life are described. 7.8% of the children ingested poison, 4.9% were burned, and 21.4% experienced other accidents for which medical advice was sought. The children who had been poisoned were of significantly lower intelligence than the remainder although those who had had other accidents did not differ significantly in this respect. The mothers of children poisoned or who had had accidents were not significantly different from the remainder in terms of general mental ability or training in child development.


Experience with a slow-release formulation of oxprenolol.

Fifteen hypertensive patients with well controlled blood pressure on antihypertensive regiments consisting of a diuretic (in all but one) and a thrice-daily regimen of oxprenolol, were switched to an equal total daily dose of slow-release oxprenolol given once daily. Other drugs were continued unchanged. Observations on blood pressure and heart rate during half-day tests (lying, standing and post-exercise) indicated a little loss of control of the blood pressure towards the end of the 24-hour period when the next daily dose was due. Ectopic beats associated with exertion were observed more frequently at the end of the 24-hour period. Maximum advantage would seem to be gained by giving slow-release oxprenolol as a twice daily regimen with two-thirds of the daily dose in the morning and one-third at night.


Medical rehabilitation unit--Palmerston North, the first four years.

The first four years of the Palmerston NORTH Medical Rehabilitation Unit are described. Reference is given to buildings, patients and staff considerations and organisation of the Unit. The outcome of the Unit's activities are discussed. Evaluation is attempted. Attention is drawn to the value of work assessment in a hospital setting.


A controlled smoking intervention programme in secondary schools.

This paper reports the result of an attempt to modify the cigarette smoking habits and attitudes of third and fourth form secondary school pupils. Baseline data was collected in two schools using an interviewer administered questionnaire. In one school a new intervention programme based on curriculum development was introduced. The other school had routine anti-smoking education only. The smoking habits and attitudes of the pupils were remeasured after seven months. In neither school was there a change in either smoking habits or attitudes. The implications of these results for future health education programmes are discussed.


A family with a high incidence of cancer.

Five generations of a family have been studied. A high number have been found to have had cancer. Although the cancers have been mainly colon and rectum they have not been confined to the large bowel. Nineteen members of the family are under the age of 20. The management of these members is discussed.


The activity of methyl benzoquate and clopidol against Eimeria maxima: synergy and drug resistance.

Synergy between clopidol and methyl benzoquate against Eimeria maxima was shown to be supra-additive. Collateral sensitivity to these drugs could not be demonstrated in resistant lines of this parasite. Resistance to methyl benzoquate and clopidol was not transferred when lines of E. maxima, resistant to the respective drugs, were propagated together. The failure to demonstrate this phenomenon was judged not to be due to synergy between the drugs. Attempts to induce simultaneous was readily acquired by a line of E. maxima resistant to clopidol. Induced resistance to clopidol in a methyl benzoquate-resistant line required numerous passages.


[Anaemia induced by vitamin B12 or folate deficiency: diagnostic value of the "dU suppression" test (author's transl)].

The "dU suppression" test, studying thymine-DNA synthesis from deoxyuridine is abnormal in folate and vitamin B12 deficiency, these two vitamins being involved in this reaction. We have done it in 7 cases of anaemia by folate deficiency, 12 cases of anaemia by vitamin B12 deficiency, in 3 cases of combined deficiency, in 3 cases of acute myeloïd leukaemia, 2 cases of sideroblastic anaemia and 2 cases of intoxication by antifolate. This test is very sensitive: it is abnormal even when there is an anaemia related to a vitamin deficiency with only very light morphologic abnormalities and can discriminate the cases, mainly in myelodysplastic syndromes, where folate deficiency is only an epiphenomen in the genesis of anaemia. The abnormalities of the "dU suppression" are quite corrected by added folate derivatives in folate deficiency. However, cobalamin derivatives did not correct completely the test in vitamin B12 deficiency except when a folate compound is also added. The "dU suppression" test becomes normal about one week after starting vitaminotherapy in vitamin B12 deficiency.


Sugar pucker geometries at the intercalation site of propidium diiodide into miniature RNA and DNA duplexes in solution.

We have evaluated the sugar pucker geometry at the intercalation site of propidium diiodide into the self-complementary dinucleoside monophosphate duplexes cytidylylguanosine and deoxycytidylyldeoxyguanosine as a function of the nucleotide/drug ratio in aqueous solution. Our solution results support the observation by Sobell and coworkers [Sobell, H.M., Tsai, C.C., Jain, S.C. & Gilbert, S.G. (1977) J. Mol. Biol. 114, 333--365] of a C3' endo (3'-5')C2' endo sugar pucker geometry in the 2:2 intercalation complex of ethidium bromide into the iodocytidylylguanosine duplex in the crystalline state. We demonstrate further that the mixed sugar pucker observed for the intercalation of propidium diiodide into the miniature RNA duplex in solution persists in the intercalative complex of this trypanocidal drug into the corresponding miniature DNA duplex in solution.


Charge stabilization mechanism in the visual and purple membrane pigments.

The effects of charged groups of rhodopsin and bacteriorhodopsin on the potential energy surface of their chromophore are examined, taking into account the protein dielectric effect. It is found that the barriers for twisting double bonds of an isolated chromophore can be drastically reduced when the chromophore interacts with the protein charges. New types of local minima are found in the ground-state potential surface of the protein-chromophore complex. These minima correspond to "charge-stabilized intermediates" which are formed when a shift of the chromophore positive charge to the ring is stabilized by the ionization of a properly placed acidic group of the protein and by partial alternation of the bond lengths of the chromophore. It is suggested that the absorption of light by rhodopsin and bacteriorhodopsin may be used not only for isomerization about double bonds, but also for trapping such charge-stabilized intermediates. Thus, for example, it is concluded that prelumirhodopsin might be still in the cis configuration. Both the mechanism of the proton pump system of the purple membrane and the dark reaction of the visual and purple membrane pigments are considered. The connection between the finding of the present work and the mechanism of storage of light energy in photobiology is indicated.


The beta bulge: a common small unit of nonrepetitive protein structure.

A beta bulge is a region between two consecutive beta-type hydrogen bonds which includes two residues (positions 1 and 2) on one strand opposite a single residue (position x) on the other strand. Compared to regular beta structure, a beta bulge puts the usual alternation of side-chain direction out of register on one of the strands, introduces a slight bend in the beta sheet, and locally accentuates the usual right-handed strand twist. Almost all beta bulges are between antiparallel strands, usually between a narrow rather than a wide pair of hydrogen bonds. Ninety-one examples are listed. The two commonest types are the "classic" beta bulge, with position 1 in approximately alpha-helical conformation, and the "G1" beta bulge, with a required glycine at position 1 in approximately left-handed alpha-helical conformation, G1 bulges almost always occur in combination with a type II tight turn. The functional roles of beta bulges probably include compensating for the effects of a single-residue insertion or deletion within beta structure and providing the strong local twist required for form closed beta barrel structures.


Insulin binding to solubilized material from fat cell membranes: evidence for two binding species.

The components of fat cell membranes responsible for the binding of insulin were solubilized by treatment with the nonionic detergent Triton X-100. By using a polyethylene glycol precipitation method to assay specific insulin binding, the soluble preparation was shown to have insulin-binding characteristics similar to those of intact fat cells. Further studies of this preparation by polyacrylamide gel electrophoresis in the presence of (125)I-labeled insulin demonstrated two distinct insulin binding activities, designated species I and II. The two species were separated by electrophoresis in the absence of iodo-labeled hormone and eluted from the gel. Scatchard analysis of the insulin binding data for species I showed a curvilinear plot with the initial portion having a K(d) of 1.3 x 10(-10) M. The Scatchard plot for species II was linear with a K(d) of 6.0 x 10(-9) M. Desoctapeptide insulin and glucagon failed to compete for the insulin-binding sites in both species whereas desalanine insulin was an effective competitor. High concentrations of proinsulin competed with the iodo-labeled hormone for binding to species I but not to species II. In the presence of a low concentration of (125)I-labeled insulin (0.3 nM) some species I activity appeared to be converted to species II activity; there was no evidence of interconversion between the two species in the absence of insulin. Neither species degraded insulin as measured by trichloroacetic acid precipitation or rebinding to intact fat cells. These findings indicate the existence in the adipocyte plasma membrane of two insulin-binding species that have distinct physicochemical properties.


Phage T4 endonuclease V stimulates DNA repair replication in isolated nuclei from ultraviolet-irradiated human cells, including xeroderma pigmentosum fibroblasts.

The repair mode of DNA replication has been demonstrated in isolated nuclei from UV-irradiated human cells. Nuclei are incubated in a mixture containing [(3)H]thymidine triphosphate and bromodeoxyuridine triphosphate in a 1:5 ratio. The (3)H at the density of parental DNA in alkaline CsCl density gradients is then a measure of repair. In nuclei prepared from WI38 cells 30 min after irradiation, repair replication is UV dependent and proceeds at approximately the in vivo rate for 5 min. Repair replication is reduced in irradiated nuclei or in nuclei prepared immediately after irradiation. It is Mg(2+)-dependent and stimulated by added ATP and deoxyribonucleoside triphosphates. No repair replication is observed in nuclei from xeroderma pigmentosum (complementation group A) cells. However, upon addition of coliphage T4 endonuclease V, which specifically nicks DNA containing pyrimidine dimers, repair replication is observed in nuclei from irradiated xeroderma pigmentosum cells and is stimulated in WI38 nuclei. The reaction then persists for an hour and is dependent upon added ATP and deoxyribonucleoside triphosphates. The repair label is in stretches of roughly 35 nucleotides, as it is in intact cells. Added pancreatic DNase does not promote UV-dependent repair synthesis. Our results support the view that xeroderma pigmentosum (group A) cells are defective in the incision step of the DNA excision repair pathway, and demonstrate the utility of this system for probing DNA repair mechanisms.


Identification of 5,8-oxyretinoic acid isolated from small intestine of vitamin A-deficient rats dosed with retinoic acid.

A retinoid was isolated by a multistep procedure from the small intestines of vitamin A-deficient rats given a single dose of retinoic acid. The compound, designated 8II, was pure, as demonstrated by four high-pressure liquid chromatographic procedures. It was positively identified as 5,8-oxyretinoic acid by ultraviolet spectrophotometry, mass spectrometry, and spectral and chromatographic comparison to known compounds. It is probable that 5,8-oxyretinoic acid was produced from 5,6-epoxyretinoic acid under the acidic conditions used in the isolation. It is highly probable, therefore, that the natural product is 5,6-epoxyretinoic acid.


Purification of the tetrodotoxin-binding component associated with the voltage-sensitive sodium channel from Electrophorus electricus electroplax membranes.

The tetrodotoxin-binding component associated with the voltage-sensitive sodium channel from electroplax  membranes of Electrophorus electricus has been purified. The toxin-binding site could be efficiently solubilized with Lubrol-PX, resulting in an extract of high initial specific activity. Purification was facilitated by the development of a rapid, quantitative binding assay. The binding component was stabilized during purification by the use of mixed lipid/detergent micelles of defined composition, and by the saturation of the site with tetrodotoxin. The purification was achieved by means of a highly selective adsorption of the toxin-binding component to DEASE-Sephadex A-25, followed by desorption at high ionic strength and chromatography over Sepharose 6B. Final peak specific activities were at least 50% of the specific activity expected for a pure, undenatured toxin-binding componenet of 230,000 molecular weight. The purified material exhibited a sedimentation coefficient of approximately 8 S and an unusual Stokes radius of 95 A. Purified material showed a relatively simple pattern on sodium dodecyl sulfate/polyacrylamide gel electrophoresis, being comprised of only three polypeptides.


Peroxidized coelenterazine, the active group in the photoprotein aequorin.

The photoprotein aequorin emits light by an intramolecular reaction when Ca2+ is added under either aerobic or anaerobic conditions. Previously reported evidence has indicated two possibilities: (i) the functional group of aequorin is coelenterazine itself, a compond that plays key roles in the bioluminescence of various other types of organisms, or (ii) it is the enolized form of this compound. Present data rule out both of these possibilities, through elucidation of the structure of the yellow compound that is split off aequorin by treatment with NaHSO3. The yellow compound is now shown to be a tertiary alcohol of coelenterazine on the basis of chemical reactions, mass spectral data, and relationships to known derivatives of coelenterazine. From this structure and the method of forming the yellow compound from aequorin, aequorin evidently contains a peroxide of coelenterazine as the active group. The presence of such a peroxide is consistent with the fact that aequorin yields free coelenterazine upon treatment with Na2S2O4. Although there is no applicable technique at present to determine with assurance the specific state of the peroxide in the protein, a study with 18O tracer indicates that a linear peroxide structure is more likely than the alternative possibility of a dioxetane structure.


Conformation of dopamine at the dopamine receptor.

Tritiated dopamine was used to label the dopamine receptor in membranes isolated from the rat corpus striatum. Scatchard analysis of displacement of [3H]dopamine by nonradioactive dopamine indicated the presence of two binding sites. The similarities in affinity, capacity, and drug specificity of the high-affinity site in the striatal membranes from rat and the binding site in the membranes from the calf caudate nucleus suggest that [3H]dopamine labels the same site in both species. In order to determine what conformation of dopamine is preferred at the dopamine receptor site, conformationally restricted analogs of dopamine--namely, the cis and trans 2-amino-1(3,4-dihydroxyphenyl)cyclobutane hydrochlorides--were tested for their affinity to the receptor. Compared to the cis conformation, the trans-restricted analogs had more affinity for the receptor site, indicating that dopamine probably interacts with the receptor in the trans conformation.


Selective complexing of the "nuclear" 5S estradiol receptor by a serum component, 5S-CA.

A component present in several sera interacts selectively with the 5S "nuclear" form of estradiol receptor but not with the 4S "cytosol" form. This component is therefore referred to as "5S-complexing activity (5S-CA)." This selective interaction occurs with 5S receptor from mouse, calf, or rat. In addition, 5S-CA recognizes the nuclear form of the receptor from hypothalamic as well as uterine tissue Thus, 5S-CA indicates a general similarity in the chemical nature of 5S nuclear receptors prepared from several sources. Using 5S-CA as a chemical probe for the nuclear form of the estradiol receptor, I have shown the chemical as well as physical similarity of 5S receptors prepared in vivo (by injection of [3H]estradiol and subsequent isolation from nuclear/myofibrillar extracts) and in vitro (by labeling of cytoplasmic extracts and subsequent chromatography on columns of DNA-cellulose). These results indicate a distinctive chemical property of nuclear 5S forms of estradiol receptor. The data are interpreted with regard to models for 5S receptor formation. 5S-CA was found in sera from animals immunized against various antigens. The importance of testing for 5S-CA in antisera directed against steroid derivatives, steroid receptors, and other steroid-binding proteins is discussed.


Inverted repeated DNA from Chinese hamster ovary cells studied with cloned DNA fragments.

Fragments from the DNA of Chinese hamster ovary cells produced by restriction endonuclease EcoRI were cloned in Charon 16A lambda bacteriophage and examined for the ability to hybridize in situ with 32P-labeled double-stranded regions from heterogeneous nuclear RNA (hnRNA). Of 235 clones tested, 87 (37%) contained sequences that hybridized with the double-stranded hnRNA. Nine of these were examined for the presence of inverted repeat DNA structures (ir-DNA) by electron microscopy. All nine contained at least two elements of ir-DNA. Analysis of heteroduplexes formed from the DNAs of the different clones as well as T1 fingerprint analysis of the double-stranded hnRNA hybridized to each of the nine clones suggest that there is detectable nucleotide sequence homology in the various ir-DNAs. There are ca 3 X 10(5) ir-DNA pairs in the haploid Chinese hamster ovary cell genome.


Hapten mimic elicits antibodies recognizing prostaglandin E2.

Antibodies that recognized the prostaglandin (PG) E structure were elicited from rabbits. 9-Deoxy-9-methylene-PGF2alpha, a stable isosteric mimic of PGE2, was conjugated to two different protein immunogens and the immune response system was duped into producing antibodies with poor recognition for prostaglandins other than the hapten mimic (9-deoxy-9-methylene-PGF2alpha) and its isosteric counterparts (PGE1 and PGE2). With this procedure, crossreaction that would ordinarily arise from the chemical or metabolic instability of an authentic PGE2 immunogen was avoided. Antibodies raised against a keyhole limpet hemocyanin conjugate of 9-deoxy-9-methylene-PGF2alpha had an average intrinsic association constant, Ko = 2.6 X 10(9) liters.mole-1, for PGE2. Crossreaction was low for a number of related prostaglandins, and a sensitive radioimmunoassay procedure with a detection limit of 6 pg was developed.


Nitrogenase and nitrogenase reductase associate and dissociate with each catalytic cycle.

Nitrogenase and nitrogenase reductase dissociate after each electron is transferred between them, as shown by the occurrence of a lag phase approximately as long as the average turnover time of nitrogenase before hydrogen evolution occurs. Because nitrogenase was present in the reaction mixture in large excess over nitrogenase reductase, the electrons donated by nitrogenase reductase must have been distributed randomly over all of the nitrogenase present. This is accomplished by nitrogenase reductase molecules associating randomly with nitrogenase molecules for each cycle of electrons transferred. The fact that ATP is hydrolyzed without a lag indicates both that electron transfer occurs during the lag and the ATP hydrolysis is coupled to electron transfer from nitrogenase reductase to nitrogenase and not to substrate reduction. The observations support the suggestion that it now is desirable to alter nomenclature to designate the MoFe protein as nitrogenase and the Fe protein as nitrogenase reductase.


DNA unwinding induced by photoaddition of psoralen derivatives and determination of dark-binding equilibrium constants by gel electrophoresis.

Derivatives of furo[3,2-g]coumarin (psoralen) can bind to the DNA double helix and, in the presence of long-wavelength UV light, the bound psoralen may react covalently with pyrimidine residues on one or both strands of the helix. By using agarose gel electrophoresis, we have determined the unwinding angle associated with each of four different psoralen derivatives to be 28 degrees +/- 4 degrees . For 4,5',8-trimethylpsoralen (trioxsalen) the unwinding angle was found to be independent of the initial DNA superhelix density in the range that is accessible to agarose gel electrophoresis. Also by using agarose gel electrophoresis, we have determined the unwinding angle for ethidium intercalation. This was done by the total relaxation of supercoiled DNA in the presence of a series of ethidium concentrations. By using published values for the association constant for ethidium binding to DNA and evaluating the final superhelix density (after removal of ethidium) of the DNA on gels, we calculated an unwinding angle of 29 degrees +/- 3 degrees . Assuming an unwinding angle of 28 degrees for the noncovalent intercalation of psoralen derivatives, we used the same procedure to determine intercalation binding constants. The association constants for 4'-aminomethyltrioxsalen were 300-1400 M(-1) in NaCl at 0.2-0.05 M and 300-2500 M(-1) in Mg(2+) at 4-0.5 mM. The association constant for 4'-hydroxymethyltrioxsalen in 0.5 mM Mg(2+) was determined to be 70 M(-1).


Mode of action of the hemin-controlled inhibitor of protein synthesis: studies with factors from rabbit reticulocytes.

Previously [de Haro, C., Datta, A & Ochoa, S. (1978) Proc. Natl. Acad. Sci. USA 75, 243--247] it was shown with initiation factors from Artemia salina embryos that the activity of the initiator methionyl-tRNA binding factor eIF-2 is stimulated by another factor (ESP, for eIF-2 stimulating protein) present, like eIF-2, in ribosomal salt washes. Incubation of eIF-2 with translational inhibitor from rabit reticulocytes, in the presence of ATP, abolished the ESP effect. At physiological concentrations eIF-2 was virtually inactive without ESP. These observations indicated that the translational inhibitor acts by converting eIF-2 to a form that is not stimulated by ESP. The same observations have now been made with eIF-2 and ESP from rabbit reticulocytes but, in this case, the dependence of eIF-2 activity on ESP is much more pronounced than with the A. salina factors. eIF-2 from reticulocytes interacts with ESP from A. salina and conversely.


Nucleosomes associated with newly replicated DNA have an altered conformation.

In vitro DNA synthesis was studied in HeLa cell nuclei, with emphasis on the question of whether newly replicated DNA is associated with nucleosomes. The newly replicated DNA was twice as sensitive to digestion by micrococcal nuclease as mature chromatin DNA, reaching a limit digest at 20-25% acid-insoluble product. Examination of the intermediates of digestion by micrococcal nuclease showed the nuclease-resistant, new DNA to be complexed in nucleosomes. However, structural differences were evident at both the polynucleosomal and the core particle level. The nucleosomes on newly replicated DNA were arranged with a repeat size of 165-170 base pairs-i.e., smaller than the 185-base-pair repeat of mature chromatin. The heterogeneity of polynucleosomal multimers, evident in digests of whole chromatin, was reduced in newly replicated chromatin such that the multimers resolved as sharply defined bands. Nucleosomal core particles associated with newly replicated DNA had a different conformation from particles in mature chromatin based on the following lines of evidence: (i) during micrococcal nuclease digestion, the monomer nucleosomes did not accumulate but were rapidly degraded under certain conditions; (ii) micrococcal nuclease limit digest patterns and DNase I digestion patterns, both of which reflect internal nucleosomal protein DNA associations, differed significantly from control patterns. These findings bear directly on models postulated for nucleosome-DNA interactions during chromation replication. A possible mechanism to account for the conformational change and its role in replication are discussed.


Amino-terminal sequence analysis of the structural proteins of Sindbis virus.

The structural proteins of Sindbis virus, an enveloped virus which belongs to the Togavirus family, have been subjected to automated Edman degradation using improved techniques. Extensive NH2-terminal sequences of about 50 residues were determined for each of the two membrane glycoproteins. In both cases the NH2 terminus of the molecule was found to be similar in composition to typical water-soluble proteins. The viral capsid protein was found to have a blocked alpha-amino group. This is consistent with other observations that viral proteins derived from the NH2 terminus of precursor molecules are often blocked.


Structural polymorphism within the amino-terminal region of MM, NN, and MN glycoproteins (glycophorins) of the human erythrocyte membrane.

MM, NN, and MN glycoproteins of human erythrocytes from single donors were cleaved by cyanogen bromide into three fragments-A, B, and C-which, upon gel electrophoresis, appeared to be common to the three antigens. Phenol/aqueous urea partitioning and gel filtration were used to separate the peptides quantitatively. Peptide C lacked carbohydrate and homoserine and represented the carboxyl-terminal portion of the glycoproteins. Peptides A and B contained one homoserine each and accounted for all the carbohydrate of the glycoproteins. The peptide portion of glycopeptide A from MM, NN, or MN antigens consisted of eight amino acid residues, of which six were homologous and two varied according to blood type. The variants were serine and glycine in glycopeptide A(MM), leucine and glutamic acid in A(NN), and half-residues of serine, glycine, leucine, and glutamic acid in A(MN). Serine was the amino-terminal residue in A(MM), leucine in A(NN), and one half residue of serine and leucine in A(MN). Each glycopeptide carried two tetrasaccharides (2 NANA, 1 Gal, 1 GalNAc) and one trisaccharide (NANA, Gal, GalNAc) linked O-glycosidically to one serine and two threonines as determined by beta-elimination and sulfite addition. The carbohydrate units were attached to serine and threonine located in the invariant region, because the amino-terminal serine residue could be oxidized by periodate. The M-N antigens are believed to be products of allelic genes which are expressed exclusively in homozygotes and equimolarly in heterozygotes.


Mutations of bacteriophage T7 that affect initiation of synthesis of the gene 0.3 protein.

Two different mutations that greatly diminish the rate of synthesis of the gene 0.3 protein of bacteriophage T7 have been characterized. One is in the initiator triplet for the 0.3 protein, changing it from AUG to ACG. This mutation was found to have little effect on binding of ribosomes to the 0.3 mRNA in vitro, although 0.3 protein synthesis was greatly depressed in vitro as well as in vivo. A suppressor mutation that partially restores the wild-type rate of synthesis was found to lie within the 0.3 RNA but not close to the mutant ACG (more than 64 nucleotides away). The second mutation is a G-to-A transition located 11 bases to the 5' side of the initiator AUG. This change eliminates a possible five-base pairing with a sequence near the 3' end of 16S ribosomal RNA, an interaction previous workers have proposed to be important for initiation of protein synthesis. This mutation causes the site of ribosome binding to shift about 15 bases to the 3' side, centering on an internal AUG, but this new site has only a poor potential interaction with 16S RNA. A suppressor mutation that restores the rate of 0.3 protein synthesis to essentially wild-type levels and also restores wild-type ribosome-binding behavior was found to lie adjacent to the original mutation, creating a new four-base complementarity with 16S RNA. These results provide strong support for the idea that a pairing interaction between mRNA and 16S RNA is involved in specific initiation of protein synthesis in Escherichia coli and indicate that this interaction may be important in selecting the site in mRNA at which the ribosomes bind.


Moleuclar field theory of reversible unfolding of biopolymers.

A simple and general model of reversible conformational changes in biopolymers that lends itself to accounting for cooperativity without resort to a detailed description of the elementary steps is presented. It is suggested that the model permits the description of transitions in specific instances in which long-range effects are present and no simplifying feature allows for a more detailed theory in a straightforward way. The proposed phenomenological approach is based on the concept of molecular field which led to the first theory of ferromagnetism. Equations are given for the temperature dependence of optical properties and of the specific heat, from which the cooperativity parameter introduced by the theory can be obtained when the reaction enthalpy of the elementary step or the number of concerted elements is known. In the limit of a strong molecular field, heterogeneity in composition of a melting sequence does not affect the sharpness of the corresponding transition. Accounting for long-range effects allows for all-or-none transitions that are sharper than those derived from the two-state model. The feasibility of applying the molecular field concept is illustrated by comparing the results for poly(A).2 poly(U) triple helices (which exhibit hysteresis) and those for poly(A).poly(U) double helices (which separate reversibly).Tertiary structure is considered, among the sources of cooperativity that possibly may be represented in terms of a molecular field. On the basis of recent results for tRNA(1) (val), it is suggested that the proposed approach may be applicable, in particular, to transfer ribonucleic acids.


Determination of molecular motion in membranes using periodic pattern photobleaching.

The lateral diffusion of a fluorescent phospholipid probe in oriented multibilayers of dimyristoylphosphatidylcholine has been measured by observing the redistribution of fluorescence after photobleaching of the membranes in a periodic pattern of parallel stripes. The diffusion constant D of the fluorescent lipid was found to vary between 1.5 X 10(-11) cm2/sec at 9.6 degrees and 2.0 X 10(-10) at 22.5 degrees in the monoclinic phase. Preliminary studies of dipalmitoylphosphatidylcholine liposomes in the Lbeta' and Pbeta' phases yielded diffusion constants of the order of 10(-11) cm2/sec. These data are relevant to earlier discussions of the rate of complement activation by hapten-sensitized liposomal membranes [Brûlet, P. and McConnell, H. M. (1976) Proc. Natl. Acad. Sci. USA 73,2977--2981; Parce, J. W., Henry, N. and McConnell, H.M. (1978) Proc. Natl. Acad. Sci. USA 75, 1515--1518)]. We have also used this method to study the motion of fluorescent antibodies bound to murine EL-4 tumor cells. Pattern photobleaching techniques have the advantages that cellular or liposomal translation has no major adverse effect on the measurements, that certain nondiffusive motions can be detected and characterized, and that diffusive or other motions can be recorded photographically.


In vitro differentiation of a fast Na+ conductance in embryonic heart cell aggregates.

Aggregates of 3-day chick cardiac myocytes, after 2 days of gyration culture, lack a tetrodotoxin-sensitive, fast Na+ conductance. After 2--3 additional days in vitro these aggregates were shown by three different criteria to have developed such a conductance mechanism: (a) action potential upstroke velocities greater than 90 V/sec; (b) suppression of spontaneous activity by tetrodotoxin; and (c) presence of a fast component of inward current recorded during voltage clamp. These membrane properties were similar to those of aggregates derived from 7-day hearts that had developed in ovo. The differentiation of fast Na+ conductance channels was a dependent upon active protein synthesis but not upon the presence of exogenous macromolecules.


Role of estrogen receptor binding and transcriptional activity in the stimulation of hyperestrogenism and nuclear bodies.

The effects of estradiol and nafoxidine on nuclear estrogen receptor binding, RNA polymerase activities, and uterine ultrastructure were studied. Animals were either injected with estradiol, implanted with estradiol/paraffin pellets, or injected with nafoxidine. Animals treated with nafoxidine or estradiol implants showed sustained long-term nuclear retention of estrogen receptor and increased nuclear RNA polymerase activities for up to 72 hr. A single injection of estradiol caused initial increases in these variables which returned to control levels by 24 hr after hormone treatment. Uterine tissue was examined by light and electron microscopy 72 hr after hormone treatments. Uteri from eith estradiol-implanted or nafoxidine-treated animals showed markedly increased hypertrophy of the luminal epithelial cells. Nuclei in sections of the uteri of these hyperestrogenized animals displayed a large number and wide array of nuclear bodies composed of a filamentous capsule and granular cores. We conclude that hyperestrogenization, a condition that eventually results in abnormal cell growth, is correlated with increased and sustained nuclear binding of the estrogen receptor, increased and sustained RNA polymerase activity, and the appearance of nuclear bodies.


De novo induction of a gene product during heterologous epithelial--mesenchymal interactions in vitro.

Mesenchymal specification of epithelial cytodifferentiation and morphogenesis has been considered to be a general feature of various epithelial-mesenchymal interacting systems (e.g., salivary gland, mammary gland, feather, hair, and tooth morphogenesis). In contrast, we have demonstrated that a mesenchyme can be induced by a heterologous epithelium to synthesize in quantity a specific gene product(s) unorthodox to the organ from which the mesenchyme was taken. Stage 22-23 avian limb bud epithelium induced 17-day embryonic mouse tooth mesenchyme to differentiate into cartilage. Peptide analysis (cyanogen bromide cleavage after purification of extracted collagen chains) demonstrated that heterologous tissue recombinations produced type II collagen [alpha(II)](3) (i.e., cartilage-type) in addition to type I collagen [alpha(I)](2)alpha(2). Intact or reconstituted mouse molar tooth organs synthesized type I collagen and type I trimer [alpha(I)](3) collagen. Immunohistochemical criteria using anti-type II collagen antibodies identified type II collagen in cartilage-like matrix within the mesenchymal component of heterologous tissue recombinants. Cartilage has never been described during in vivo or in vitro tooth tissue differentiation or associated with the pathology of dental papilla mesenchyme. These results support the hypothesis that epithelial-mesenchymal interactions during embryonic development can selectively induce de novo synthesis of unique gene products.


Induction of murine erythroleukemia differentiation by actinomycin D.

Murine erythroleukemia cells are induced to differentiate by 0.5-5 ng of actinomycin D per ml. Murine erythroleukemia cells cultured with actinomycin D prolong cell doubling time but achieve the same density after 5 days as cells without inducer. Actinomycin D causes over 95% of the cells to become benzidine-reactive. [(3)H]Actinomycin D uptake into DNA can be detected within 2 hr and reaches a maximum (approximately 0.1 pmol/10(6) cells) by 10-12 hr. It is estimated that about one out of 10(5) dG.dC pairs is bound to actinomycin D. Commitment to differentiation, assayed by transfer of cells to culture without inducer, was detected as early as 5 hr. Unlike Me(2)SO, which causes a transient prolongation in G(1) at about 15-20 hr, cells cultured with actinomycin D show a more sustained increase in the proportion of the cells in G(1). Globin mRNA accumulation was detectable by 19 hr in culture. Alteration in DNA stability in alkaline sucrose gradients was detected by 19 hr. Actinomycin D induces synthesis of Hb(maj) and Hb(min) in approximately equal amounts. A decrease in rates of synthesis of RNA, DNA, and total protein occurs in cells cultured with actinomycin D, as well as in cells cultured with Me(2)SO. No evidence for an early action of actinomycin D at the plasma membrane was obtained by measurement of changes in cell volume or (86)RbCl uptake. Taken together, the present results indicate that actinomycin D is a potent inducer of differentiation of murine erythroleukemia cells and suggest that the target of its effect may be at the level of DNA.


Steroid hormones mediate reversible phenotypic transition between transformed and untransformed states in mouse fibroblasts.

Hydrocortisone at physiological concentrations reversibly inhibits DNA synthesis in ST1 cells (a line of mouse fibroblasts possessing 40 chromosomes and derived from Swiss 3T3 cells). This inhibitory activity is a property of glucocorticoids, but the beta-OH of C-11 of glucocorticoids is not essential for the inhibition. The steroid hormone restores to ST1 cells dependency on serum, density, and anchorage for growth. When injected into nude mice, ST1 cells generated malignant invasive fibrosarcoma. Injections of dexamethasone into tumor-bearing animals blocked tumor growth. The steroid hormone seems to induce a reversible transition between a transformed and a "normal" phenotype. ST1 cells treated or untreated with hydrocotisone are not responsive to fibroblast growth factor, epidermal growth factor, or prostaglandin F2alpha whereas they are responsive to a factor that is a contaminant in bovine serum albumin.


Coordinate control of 3T3 cell proliferation by platelet-derived growth factor and plasma components.

DNA synthesis and cell division were measured in Swiss mouse 3T3 cells cultured in different concentrations of cell-free plasma-derived serum and increasing amounts of a platelet-derived growth factor. In plasma-derived serum alone, the cells were quiescent and they were arrested in the Go/G1 phase of the cell cycle. Addition of a platelet-derived growth factor to quiescent cells maintained in plasma-derived serum stimulated both DNA synthesis and cell division. When plasma components were present at high concentration (5%, vol/vol), the amount of platelet factor added to the cultures determined the number of cell doublings. Plasma-derived molecules were required for the platelet factor to stimulate DNA synthesis and cell division in the maximal number of cells. In addition, plasma components had to be present for recently divided cells to respond to the platelet factor. When 3T3 cells were cultured in excess platelet factor and limiting amounts of plasma-derived serum (0.5%, vol/vol), the cells underwent one doubling and then ceased to proliferate. Addition of fresh plasma-derived serum to these cells induced a second round of cell division. Plasma components and the platelet-derived growth factor acted in a coordinate fashion to regulate the proliferation of Swiss 3T3 cells.


Endocytosis of cholera toxin into neuronal GERL.

Cholera toxin linked covalently by glutaraldehyde to horseradish peroxidase was incubated with cultured chicken sympathetic neurons at 4 degrees. Cells were washed and brought to 37 degrees to permit endocytosis of bound toxin on plasma membranes. Massive internalization of the ligand into vesicles and cisterns of the Golgi--endoplasmic reticulum--lysosome (GERL) system was demonstrated by the cytochemical reaction for the enzyme. Surface binding and subsequent endocytosis of the cholera toxin--enzyme conjugate was inhibited when conjugate and monosialoganglioside (GM1) were simultaneously applied to cells at 4 degrees. Cholera toxin is not toxic to neurons at the levels used. These results indicate that GERL is the primary site of endocytosis of presumed complexes of cholera toxin with its plasma membrane receptor (GM1 ganglioside-containing moieties). It is suggested that, in neurons, plasma-membrane bound ligands are taken up primarily into GERL.


Existence of only a single functional pool of adenosine triphosphate in human erythrocytes.

The question of whether separate "membrane" and "soluble" pools of ATP exist in erythrocytes has been examined. Phosphoglycerate kinase (EC 2.7.2.3)-derived ("membrane") ATP was labeled by short-term incubation with inorganic [32P]phosphate. Pyruvate kinase (EC 2.7.1.40)-derived ("soluble")ATP is not labeled under these circumstances. The specific activity of the gamma-phosphate of "soluble" ATP was then evaluated by the addition of 2-deoxyglucose and measurement of the specific activity of 2-deoxyglucose-6-[32P]phosphate formed. This specific activity was essentially the same as the overall specific activity of erythrocyte ATP gama-phosphate, indicating that no functional pools of phosphoglycerate kinase-derived and pyruvate kinase-derived ATP exist in erythrocytes.


Somatic cell origin of teratocarcinomas.

Malignant teratocarcinomas arise from developmentally totipotent normal stem cells. Whether the targets are embryonal somatic cells or germinal cells has long been a matter of controversy. Past experiments on teratocarcinoma induction by ectopic grafting of early rodent embryos or fetal germinal ridges have remained ambiguous because embryos ordinarily soon form germ cells, and parthenogenetic germ cells form "embryos." In order to interrupt the developmental cycle at its most telling point, day 6 (egg-cylinder stage) mouse embryos of genetically sterile types were grafted; in such grafts, only a terminal residue of totipotent embryonal somatic ("ectoderm") cells is available, and subsequent germ cell development is severely impaired. One graft series, from S1(J)/+ matings, comprised 25% S1(J)/S1(J) presumptive sterile embryos; these grafts formed tumors containing embryonal carcinoma cells as often (47%) as did control +/+ grafts (41%) on the same genetic background. In another series, from W/+ matings, tumors of the sterile W/W genotype were individually identified by means of a closely linked marker, phosphoglucomutase (PGM, EC 2.7.5.1; Pgm-1 locus), coding for electrophoretic enzyme variants and incorporated into the stock. Four tumors were obtained (out of 16) that had the PGM-1D phenotype diagnostic for W/W, and that also contained embryonal carcinoma cells. Therefore, the malignancy arises here in susceptible somatic embryonal stem cells at the terminal stage of their capacity for totipotency. Other teratocarcinomas-whether induced or spontaneous-of ostensible germ-cell origin by parthenogenesis may also depend upon development of the same somatic target cells before neoplastic conversion can occur. A general model based on these experiments is proposed for all malignancies: Malignant transformation of a particular kind of normal stem cell may be possible only when that stem cell has progressed to the threshold of further differentiation.


An ordered sequence of events is required before BALB/c-3T3 cells become committed to DNA synthesis.

An ordered sequence of events must be completed before cells become committed to synthesize DNA. A platelet-derived growth factor (PDGF), present in heated (100 degrees ) extracts of human platelets, induces density-inhibited BALB/c-3T3 cells to become competent to proliferate. Platelet-poor plasma induces these competent cells to leave the competence point, progress through G(0)/G(1), and enter the S phase. Treatment of G(0)-arrested, incompetent cells with plasma, before the addition of PDGF, did not shorten the latent period for DNA synthesis or increase the rate of entry into the S phase. Growth arrest points in the plasma-dependent progression sequence were detected in G(0)/G(1). PDGF-treated competent cells were exposed to an optimal concentration of plasma (5%) for various lengths of time and were then transferred to medium lacking plasma; the subsequent readdition of plasma stimulated the cells to enter the S phase. The lag period until DNA synthesis, in such experiments, was dictated by the length of the initial exposure to plasma. PDGF-treated competent cells that were incubated with plasma for 5 hr during the initial exposure did not leave the competence point; they began DNA synthesis 12 hr after the readdition of plasma. However, a population of cells treated with plasma for 10 hr became arrested at a point 6 hr before DNA synthesis, whereas a population treated with plasma for 12-15 hr became arrested at a point immediately before DNA synthesis. Cells remained arrested at this latter point for as long as 24 hr, and these arrested cells were not committed to DNA synthesis. The addition of plasma induced immediate entry into the S phase with an apparent first-order rate of entry being determined by the plasma concentration. This plasma-dependent commitment (transition) to DNA synthesis was blocked by cycloheximide but not by hydroxyurea. Removal of the hydroxyurea allowed cells to enter the S phase synchronously in the absence of plasma.


Cloned single repeating units of 5S DNA direct accurate transcription of 5S RNA when injected into Xenopus oocytes.

Single and multiple repeating units of three types of Xenopus 5S DNA recombined with the plasmid pMB9 serve as templates for the accurate synthesis of 5S RNA after their injection into Xenopus laevis oocyte nuclei. All 15 cloned single repeating units of X. laevis oocyte 5S DNA that were tested supported 5S RNA synthesis. Three cloned fragments of X. borealis oocyte 5S DNA and one cloned single repeating unit of X. borealis somatic 5S DNA were templates for 5S RNA synthesis. We conclude that the majority of repeating units of 5S DNA in these multigene families contain the information for accurate initiation and termination of 5S RNA synthesis. The ability of this system to detect sequence changes that affect transcription is demonstrated.


Stepwise mutation model and distribution of allelic frequencies in a finite population.

A mathematical theory is developed that enables us to derive a formula for the equilibrium distribution of allelic frequencies in a finite population when selectively neutral alleles are produced in stepwise fashion (stepwise mutation model). It is shown that the stepwise mutation model has a remarkable property that distinguishes it from the conventional infinite allele model (Kimura-Crow model): as the population size increases indefinitely while the product of the effective population size and the mutation rate is kept at a fixed value, the mean number of different alleles contained in the population rapidly reaches a plateau which is not much larger than the effective number of alleles (reciprocal of homozygosity).


Genetic analysis of the G1 period: isolation of mutants (or variants) with a G1 perior from a Chinese hamster cell line lacking G1.

Cells of the Chinese hamster line V79-8 multiply without a G1 period (i.e., they are G1(-)) and have an average generation time of 9.5 hr. After mutagenesis and selection we have derived five stable mutants (or variants) of this line that have longer generation times. In each case the increase in generation time is due solely to the introduction of a G1 period into the cell cycle, with no measurable effect on S, G2, or M. Fusions among these five G1(+) mutant lines and another presumably nonmutant G1(+) line (V79-743) produce hybrid cells lacking a G1 period in all but one case. These complementation tests define five complementation groups among these six G1(+) cell lines. The six G1(+) lines represent five different causes or bases for the presence of a G1 period. The two G1(+) mutants belonging to complementation group V are temperature sensitive for expression of the G1(+) phenotype (G1 congruent with 0, 4, and 6 hr at 33 degrees , 37 degrees , and 39 degrees , respectively). In all cases the G1(-) state is dominant over the G1(+) state, suggesting that the presence of G1 represents a "deficient" condition. Mutants of this type may be useful in the analysis of the switch from G1(-) to G1(+) that occurs normally in cleaving embryos and in elucidation of the genetic mechanism(s) responsible for the presence of a measurable G1 in most cells.


Nutritional inhibition of genetically determined renal disease and autoimmunity with prolongation of life in kdkd mice.

Striking inhibition of development of renal disease and prolongation of lifespan have been achieved in kdkd mice by restricting their daily food intake. Restricting protein intake alone did not prolong life nor did it inhibit development of kidney disease. The kdkd nephronophthisis, although very different histologically from the renal disease of B/W mice, may also have immunological components. Like the immunologically based renal disease of B/W mice, renal disease in kdkd mice is decreased or eliminated histologically by dietary restriction, which inhibits development of autoimmunity directed toward the erythrocytes of these mice. Further analysis will be needed to elucidate the cause of progressive renal disease in both the kdkd and B/W models and to permit understanding of the profound influence of restriction of food intake on development and progression of these very different renal diseases.


Muscarinic cholinergic receptors in murine lymphocytes: demonstration by direct binding.

Using [3H]quinuclidinyl benzilate as a specific cholinergic muscarinic ligand, it has been demonstrated that lymphocytes have muscarinic binding sites. There are approximately 200 sites per cell and the dissociation constant for quinuclidinyl benzilate is approximately 1 X 10(-9) M. Quinuclidinyl benzilate receptor binding is blocked by atropine and oxotremorine.


Primary structure of murine major histocompatibility complex alloantigens: isolation, biochemical characterization, and preliminary alignment of CNBr fragments from the H-2Ib glycoprotein.

Radiochemical methodology has been applied in studies directed toward the determination of the amino acid sequence of the murine H-2Kb gene product. Five major CNBr fragments, which comprise the NH2-terminal 80% of the intact glycoprotein and include the H-2Kb fragment isolated by papain cleavage, were isolated and characterized. By means of amino-terminal sequence analysis, homology to other products of the major histocompatibility complex, identification of partial CNBr cleavage products, and localization of the site of papain cleavage, it was possible to align the fragments obtained from the molecule in the following order: the NH2-terminal fragment, designated IIIn, contains 23 residues and is followed by fragment IIIa, which contains 29 residues. Two peptides Ib (Mr 11,500) and Ia (Mr 12,000), each of which contains a carbohydrate moiety, are followed by fragment Ic (Mr 5800), which includes the site of papain cleavage. The data indicate the presence of disulfide bonds between fragments Ib and Ia and between Ia and Ic.


Diabetic cataract formation: potential role of glycosylation of lens crystallins.

A high glucose concentration in vivo or an increased glucose of glucose 6-phosphate concentration in vitro has been found to lead to the glycosylation of epsilon-amino groups of lysine residues in bovine and rat lens crystallins. In vitro, this glycosylation imparts an increased susceptibility of the crystallins to sulfhydryl oxidation. Disulfide crosslinks result in the formation of high molecular weight aggregates and an opalescence in the crystallin solutions. The addition of reducing agents prevents as well as reverses the formation of high molecular weight aggregates and the opalescence of the crystallins. These phenomena suggest a new interpretation of previous results on cataract formation and a new approach for development of drugs to prevent cataracts.


Endorphins may function in heat adaptation.

Administration of the opiate antagonist naloxone to rats after acute or chronic heat exposure precipitates an increase in colonic temperature, an increase in escape attempts, and a decrease in body weight. These changes are accompanied by signs associated with hyperthermia such as salivation, diarrhea, and an abnormal extended posture. Although brain endorphin involvement is possible, hypophysectomy diminishes the intensity and magnitude of these naloxone effects, indicating that the naloxone effect in intact animals may be due to a functional antagonism of pituitary endorphins. These observations suggest that endorphins attenuate physiological responses to thermal and noxious stimuli triggered in common neuroanatomical pathways by heat.


Hormonal induction of the secretory immune system in the mammary gland.

The secretory immune system of the mammary gland is undeveloped in virgin mice but becomes active at term and during lactation. This change appears to depend on migration to the mammary gland of precursors of IgA-secreting cells derived from the gut-associated lymphoid tissue, an origin which explains the specificity of milk IgA antibodies for enteric organisms. Because development of the epithelial components of the mammary gland is clearly under hormonal control, we examined the effect of mammotropic hormones on differentiation of the immune elements. Under a combined regimen of progesterone, estrogen, and prolactin, development of the glandular epithelium occurs with concomitant increments in the number of IgA-secreting plasma cells and amount of intraepithelial IgA. These increases appear to be due to enhanced capacity of the gland to attract or retain precursors of IgA plasma cells derived from gut-associated lymphoid tissue. Testosterone, which antagonizes lactation, also antagonizes development of the secretory immune system and decreases cellular trapping in the lactating gland. The ability of the gland to trap IgA immunoblasts is probably contingent upon a hormone-induced increase in receptors.