Biomedical subjects
Publications and source records attributed to M R Smith.
A method for efficient electrophoretic transfer of DNA fragments from polyacrylamide gels to nitrocellulose sheets was developed. Hybridization to these fragments can be performed by standard techniques. The method is also applicable to agarose gels, allowing this transfer method to be used for DNA ranging from 40 to at least 23,000 bp.
An evaluation of a case-based, problem-oriented, modular curriculum in geriatrics for medical students was designed by the authors to investigate (a) whether students would demonstrate cognitive knowledge gain in geriatrics, (b) whether students' attitudes toward the elderly would change favorably, (c) whether suggested learning activities in geriatrics would positively influence students' ratings of these activities in geriatrics, and (d) which institutional characteristics facilitate implementation of the new curriculum. The results indicated that using the modules did produce statistically significant gains in students' cognitive knowledge of geriatrics. Using the modules did not, however, influence the students' attitudes toward the elderly. Clinical or related learning activities involving elderly persons were rated positively by students; however, only two of the participating medical schools in the evaluation provided such experiences. Data from questionnaires and site visits identified several factors which may be helpful in the implementation of geriatrics or other new curricular material into existing curricular structures.
An experimental study was performed to assess the possible tumour-promoting action of urothelial trauma caused by repeated intravesical diathermy, catheterisation, and the instillation of water, glycine and saline in the rat bladder which had previously been exposed to an initiating dose of the carcinogen N-methyl-N-nitrosourea. An increase in tumours and inflammatory changes was observed, especially in the group treated with water, and the significance of the findings is discussed.
The purpose of this double blind clinical trial was to determine the anticaries activity of a dentifrice containing 0.78% sodium monofluorophosphate in a silica gel abrasive base compared with a placebo under conditions of supervised brushing. 1154 schoolchildren, ages 9-12, were recruited in a non-fluoridated semi-rural area of northeastern Connecticut. Subjects were stratified according to school, grade and sex, and then randomly divided into two groups. Each school day, children brushed their teeth for 1 min under supervision by project personnel. Weekend and vacation usage was ad libitum. Caries examinations and radiographic readings were performed by the same examiner (J.R.). After 12 months, the 996 subjects examined showed that the group using the test dentifrice had significantly (less than 0.05) lower DMFT (25.0%) and DMFS (19.1%) increments than the group using the placebo. After 24 months the 876 subjects examined showed that the test group continued to have significantly lower DMFT (24.5%) and DMFS (24.7%) increments than the placebo group. Surface protection after 24 months ranged from 22.1% for occlusal to 37.1% for interproximal surfaces.
Kent has made seven statements that should inspire responses from linguists, kinesiologists, and developmentalists, among others. His goal of reforming our current theoretical perspective on the development of speech will be accomplished, in part, by their corrections, elaborations, and further speculations. Not all of his statements have the same status or consequence for an evolving theory of development. Those on the anatomic and neurological differences between infants and adults are much less controversial than those on the initial separateness of the perception and production systems or those on the relation of rhythmic behavior to phonology. Across all the statements, two major topics merit discussion: 1) the relevant descriptive terms of the vocal behavior of infants and 2) the relation of vocal activity to other behavior.
From a linguistic perspective, the Bellman-Goldberg thesis of a necessary relationship between the abilities of organisms to move and communicate is very interesting. Since several concepts and terms are represented in both the thesis and contemporary linguistic literature, these items are discussed in further detail. Questions of the implicit assumptions of the homology of the motor and linguistic systems are also raised here. Finally, there are requests for further clarification on issues of evolution in this test of the strength of the thesis.
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Müllerian dysgenesis, a common developmental anomaly presenting as primary amenorrhea, is characterized by absence of the vagina and absence or rudimentary development of the uterus. Anatomic anomalies of the axial skeleton, inguinal canal, and kidney often accompany this psychologically devastating condition. Twenty-two cases are reviewed in regard to associated clinical features, principles of treatment, and adequacy of outcome. A good functional result can be achieved either by the use of a progressive nonsurgical self-dilatation technique, or by surgical cavitation with skin grafting, although histologic and steroid receptor properties of the latter are less physiologic than those of the former.
Bleeding time, coagulation tests and platelet aggregation response to adenosine diphosphate (ADP), epinephrine, arachidonic acid, ristocetin and collagen were determined in 18 normal male volunteers in a randomized, double-blind, placebo-controlled parallel study. Six subjects each received either placebo or 4.0 g of either mezlocillin or ticarcillin every 6 h for 7 days. In the placebo-treated or mezlocillin-treated groups no changes in plasma coagulation tests or bleeding time were observed. Randomly scattered decreases in platelet aggregation responses to ADP, epinephrine or arachidonic acid were noted in some subjects in both the placebo and mezlocillin groups. In contrast to these observations, in the ticarcillin treated group the bleeding time was abnormally prolonged to more than 18 min in three of six volunteers. In two of these subjects, bleeding time was prolonged after only seven ticarcillin doses (28.0 g) and in the third subject after a total of 21 doses (84.0 g). A significant decrease in platelet aggregation (P less than 0.005) induced by ADP was found in these volunteers. Although platelet aggregation response to arachidonic acid and epinephrine also appeared to be reduced in this group, correlation between increased bleeding time and abnormal platelet function was not possible because of the small number of subjects. No changes in other coagulation function were observed. The results suggest that the risk of bleeding disorder is very high with therapeutic doses of ticarcillin but not with comparable doses of mezlocillin.
Porcine mucosal heparin was chemically depolymerized. The depolymerization was stopped at different steps to obtain two low molecular weight (LMW) heparins with a molecular weight of 10 000 and 6000, respectively. The LMW heparins were tested in vitro for anti-clotting activities and for platelet serotonin release in different systems in comparison with normal heparins, dermatan and heparan sulphate. After addition of various amounts of heparin preparations to washed platelets, no significant release was observed for all tested heparins. On the contrary, different heparins showed an inhibition of serotonin-release induced by collagen in platelet rich plasma, whereas the ADP-induced release was increased. The effect on the platelet release appears related to the molecular weight. In fact, it is significant only for normal heparins whereas it is not for LMW heparins. A good relation was observed, also, between anti-activated factor X activity/antiglobal clotting activity (Xa/APTT) ratio of different heparins and the effect on platelet release.
2-Bromoethanesulfonate (BES) inhibition of methanogenesis from methanol by resting-cell suspensions or cell extracts of Methanosarcina was reversed by coenzyme M. BES inhibition of methylcoenzyme M methylreductase activity in cell-free extracts was reversed by methylcoenzyme M but not by coenzyme M. Methanol/coenzyme M methyltransferase activity was not inhibited by 10 microM BES. Inhibition of methylreductase by BES and 3-bromopropionate was competitive with methylcoenzyme M, but inhibition by 2-bromoethanol exhibited mixed kinetics. The Ki values for the inhibitors in cell-free extracts were similar to the concentrations which inhibited intact cells. BES-resistant mutants of strain 227 were apparently permeability mutants because in vitro assays showed that mutant and parent strain methylreductases were equally sensitive to BES.
More than 100,000 clinical caries trials were simulated utilizing the negative binomial distribution on a UNIVAC 1100 computer. In each trial, the raw data and logarithmic transformed data were analyzed using a standard t test analysis. The results were summarized as estimates of the power functions for each case. In almost all cases, the transformed data gave greater power than did the untransformed data. In several common situations, the differences were dramatic.
A young man developed reversible acute renal failure after a large overdose of phenazopyridine. The renal failure was treated by peritoneal dialysis. Analysis of blood and urine samples failed to demonstrate the parent drug but a metabolite with similar ultraviolet absorption was detected. No parent drug or metabolites were detected in the peritoneal dialysate.
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Ventricular enlargement in schizophrenia as measured by ventricular-brain ratio (VBR) has been described by three different research groups. Because of the possibility that the samples might not be representative of the broad population of schizophrenic patients, questions have been raised about generalizability. The authors report on ventricular enlargement in a rigorously defined but representative sample of schizophrenic patients intermittently hospitalized but living in the community. They provide additional evidence that ventricular enlargement does occur in schizophrenic patients, although not at rates as high as those previously reported. Issues related to the definition of ventricular enlargement, as well as the effects of sampling and choice of a control group, are discussed.
The authors explored the clinical correlates of ventricular enlargement in schizophrenia by comparing 16 patients with "large" ventricles (ventricles more than I SD above the control mean) with 16 patients with the smallest ventricles from a sample of 52 schizophrenic patients. Patients with ventricular enlargement showed some impairment in the sensorium and had a preponderance of "negative" symptoms (e.g., alogia, affective flattening, avolition, anhedonia), while those with small ventricles were characterized by "positive" symptoms (e.g., delusions, hallucinations, positive formal thought disorder, bizarre behavior). These findings suggest that combining a measure of brain structure with the clinical picture may provide a useful new approach to the classification of schizophrenia.