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Biomedical subjects

K Smith

Publications and source records attributed to K Smith.

At least 523 records · Page 29Linked to original sources
PubMed1982

Regulation of elastin synthesis in developing sheep nuchal ligament by elastin mRNA levels.

Levels of elastin production in explant culture of fetal sheep nuchal ligament and corresponding levels of translatable elastin mRNA were determined in parallel studies during a period of rapid growth of the embryo. The identity of the explant culture and cell-free products was confirmed by peptide mapping, immunoprecipitation, and the characteristic lack of histidine and methionine. Elastin production was quantitated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and radioimmune precipitation. The translation products could be labeled with methionine only when NH2-terminally donated as f-Met-tRNAfMet. Explant cultures showed a large rise in elastin production from 70 days after conception to 150 days after conception. Cell-free translation of RNA demonstrated a parallel in elastin mRNA levels and in elastin mRNA per cell. It appears, therefore, that the marked emphasis the differentiating nuchal ligament places on elastin production is modulated, at least in part, by the quantities of available elastin mRNA.

Aging↗
PubMed1982

The value of exercise on a psychiatric hospital unit.

A number of reports in the literature have shown the value of exercise programs in reducing depression among psychiatric patients. Most of these papers have dealt with outpatients; this paper recounts a study of hospitalized inpatients who elected to participate in a six-week exercise program. After six weeks, participants showed significant decreases in their levels of reported depression, and nonsignificant trends toward a decrease in anxiety and an increase in their sense of accomplishment. The program did not ameliorate many disturbing feelings such as anger and fear, nor did it elicit a wide range of positive affects such as cooperation and feelings of acceptance. However, the authors conclude that a well-designed exercise program has enough potential benefit to make it a regular part of a psychiatric inpatient program.

Adult↗
PubMed1982

Development of a laboratory animal model for infectious bovine keratoconjunctivitis.

Guinea pigs, gerbils, voles, golden hamsters and Chinese hamsters exposed to experimental infection with Moraxella bovis by ocular instillation or associated routes showed transient infections only and no clinical signs. Five strains of mice were of similarly low susceptibility but another, the C57 Bl strain, was relatively susceptible and treatment with corticosteroid before infection regularly produced keratoconjunctivitis. This system therefore offers a promising model for studies on infectious bovine keratoconjunctivitis.

Animals↗
PubMed1982

Sinus and atrioventricular nodal function: Preoperative and early postoperative assessment in children.

Ninety-three rapid atrial pacing studies were performed in 38 children to compare preoperative and early postoperative function of the sinus and atrioventricular (AV) nodes. The interval between the preoperative and postoperative studies was under 6 months in the majority of patients. Postoperative studies were performed within 48 hours of operation and between 4 and 8 days after operation. Sinus nodal function as measured by sinus nodal recovery time (SNRT) was an unreliable index in determining depression since the number who improved postoperatively (10/55) was nearly equal to the number that worsened (12/55). The majority who had abnormal function postoperatively demonstrated a junctional rather than sinus recovery focus. This finding appears a more definitive and more reproducible indicator of sinus node depression in the postoperative patient. Postoperative AV nodal function was decreased (as measured by the cycle length [CL] at which Wenckebach periodicity occurred) in 15 of 55 studies (27%) of the entire group. There was nearly an equal chance for improvement (24%) in function. This also applied to those patients who had sequential studies. Therefore, this method of assessment for AV nodal function was unreliable, or else the operation did not affect the node significantly. The latter is unlikely in view of late postoperative data. The greatest utility of this test was to determine the capability for AV conduction in certain patients with slow escape rhythms in the absence of surface P waves, and to differentiate complete heart block from AV dissociation when atrial activity was absent. Despite the variability of effects on the sinus and AV nodes in these patients, those who demonstrated depression had a significantly higher incidence of dysrhythmias (80% of patients with sinus nodal depression and 100% of patients with AV nodal depression).

Adolescent↗
PubMed1981

Modulation of tropoelastin production and elastin messenger ribonucleic acid activity in developing sheep lung.

During fetal development of the sheep lung, elastin content continually increases. For examination of the processes controlling this elastin accumulation, an explant culture system was characterized with respect to changes in tropoelastin production in sheep lung during fetal and early postnatal development. Relative tropoelastin production in cultured lung explants, quantitated by immunoprecipitation, was about 0.3% of total [14C] valine incorporation during the period from 55 to 104 days after conception. This percentage began to increase by 112 days after conception, reached a maximum value of about 1.0% by 135 days after conception, and then declined to 0.5% soon after birth. The absolute rate of tropoelastin production paralleled these changes in relative tropoelastin production. For evaluation of the processes controlling tropoelastin production in the developing sheep lung, total cellular RNA prepared from 68-day-old fetal, 107-day-old fetal, and 147-day-old fetal lung was translated in a rabbit reticulocyte lysate system. Elastin mRNA activity, expressed as the amount of elastin precursor translated per microgram per microgram of DNA, increased about 3-fold during fetal lung development, and elastin precursor synthesis, expressed as a proportion of total translational activity, increased in parallel. It appears, therefore, that elastin production in developing fetal lung is modulated, at least in part, by the amount of available translatable elastin mRNA present in the tissue.

Animals↗
PubMed1981

Using a battery of tests to predict suicide in a long-term hospital: a quantitative analysis.

Examined the Wechsler-Bellevue, Rorschach, TAT and Word Association Tests of 40 Patients for quantitative indications of suicide potential. Ten of these patients had completed suicide, 10 "serious" attempts, 10 "mild" attempts and 10 had never made a suicide attempt. In addition to a study of the quantification of major aspects of the tests, various published hypotheses also were examined. No quantitative aspect of the data differentiated all four groups. When the "completed" and "serious" attempters were compared to the "mild" and "no" attempters, the more lethal patients were found to give more movement responses and more total responses. Those who completed suicide also had a larger difference than others between their Verbal and Performance IQs. Of the published hypotheses, only the Roth & Blatt and Sapolsky hypotheses received significant support.

Hospitals, Psychiatric↗
PubMed1981

Developmental regulation of elastin synthesis.

The regulation of elastin production has been evaluated and compared in two systems in the developing sheep: nuchal ligament and lung. Absolute rates of production in explant culture were estimated by immunoprecipitation of newly synthesized elastin and determination of precursor pool specific activities. Lung elastin production increased about 2.5-fold while nuchal ligament production increased about 9-fold during the latter half of gestation. In comparison, the activities of elastin messenger RNA(mRNAE) of these tissues were determined in a cell-free system by immunoprecipitation. The increases in mRNAE activity largely paralleled the rises in elastin production, suggesting that elastin synthesis in these tissues is regulated, at least in part, by the availability of translationally active mRNAE.

Aging↗
PubMed1981

Effectiveness of terbutaline and theophylline alone and in combination in exercise-induced bronchospasm.

Theophylline and terbutaline, alone and in combination, were evaluated for effectiveness in treating exercise-induced bronchospasm (EIB) when used at doses that should be tolerated by adolescents taking them intermittently: theophylline, 250 mg (fast release) and terbutaline, 2.5 mg. Twenty-one subjects, 12 to 19 years of age, with EIB performed standardized exercise tests on four separate days and received either theophylline, terbutaline, the combination, or placebo in a prerandomized double-blind manner prior to exercise. Exercise tests were performed two and five hours after each study drug administration. Blood samples were drawn before and again two and five hours after drug administration for theophylline level. Pulmonary function [forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and forced expiratory flow rate (FEF 25% to 75%)] was recorded before and after exercise. All of the active treatments were better than placebo in diminishing EIB. The combination was statistically better than terbutaline or theophylline alone. The effect of theophylline was not significantly different from that of terbutaline. The combination induced significantly more tremor than either agent individually. Either drug alone or the two in combination is effective for diminishing EIB. Although the combination may have additive properties for some patients, the increased incidence of tremor may diminish its appeal. Either drug alone or in combination is effective in decreasing EIB for at least five hours, which makes them practical choices for treatment of school-aged children.

Adolescent↗
PubMed1981

Dysbaric osteonecrosis: a consequence of intravascular bubble formation, endothelial damage, and platelet thrombosis.

Survival and turnover of platelets, fibrinogen, and plasminogen were measured in association with hyperbaric exposure in man. In addition, kinetic and vascular studies were carried out in a hyperbaric swine model to assess the role of vascular injury and thrombosis in the pathogenesis of dysbaric osteonecrosis. In man, significant increases in platelet and fibrinogen consumption were directly associated with dive depth and with repetitive exposure at lesser depths. The increased destruction of platelets and fibrinogen was not accompanied by reduced blood levels because of compensatory shifts in production rats and distribution between circulating and storage compartments. Platelet consumption was substantially greater than fibrinogen destruction with respect to both severity and duration. Platelet function inhibitors decreased platelet consumption. Increased fibrinogen consumption was sometimes associated with reduced plasminogen survival, but levels of fibrinogen/fibrin degradation products were never measurably altered from normal values. The relationships among platelet and fibrinogen consumption, vascular changes, and dysbaric osteonecrosis were studied in hyperbaric swine. Consumption of hemostatic factors was most severe with rapid, uncontrolled decompression, low oxygen concentrations, and deeper or repetitive dives. Platelet consumption induced by hyperbaric exposure resolved spontaneously with time, suggesting a repair process after the simulated diving conditions were discontinued. Interruption of increased platelet and fibrinogen consumption in the swine model required either moderation of the dive profile or a combination of drugs that inhibit platelet function (dipyridamole or sudoxicam) together with an anticoagulant (warfarin or heparin). Repeated hyperbaric exposure under conditions that uniformly produced femoral osteonecrosis and consumption of platelets and fibrinogen was associated with detectable endothelial injury and arterial intimal lesion formation. Since the diving characteristics of increasing depth and inadequate decompression were associated with both the most severe consumption and the highest frequency of intravascular bubble formation, we postulate that intravascular bubbles, formed during hyperbaria, produce osteonecrosis, perhaps through the following sequence: (1) bubble-related endothelial cell damage; (2) platelet thrombus formation with secondary fibrin deposition; (3) microvascular occlusion; and (4) platelet-dependent arterial narrowing through intimal lesion formation. The role of antithrombotic therapy in the prevention of dysbaric osteonecrosis remains to be determined.

Animals↗
PubMed1981

Model workshop on nutrition counseling for dietitians.

The purpose of the workshop on nutrition counseling was twofold: (a) to enhance nutritionists' and dietitians' knowledge of counseling and basic interviewing skills, behavioral weight control counseling skills, and adherence counseling skills and (b) to quantitatively evaluate improvement and maintenance of the newly acquired skills. Changes in these areas indicated that it is possible to improve certain skills and to maintain those improvements over time.

Counseling↗