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Biomedical subjects

R B Stewart

Publications and source records attributed to R B Stewart.

At least 109 records · Page 6Linked to original sources
PubMed1987

Renal artery stenosis: an example of how the periphery can modulate voluntary alcohol drinking.

Voluntary alcohol drinking, using a free-access procedure, was studied in rats three weeks after unilateral renal artery stenosis was produced by applying a 0.20 mm solid silver clip to the left renal artery (Two-Kidney, One-Clip, Hypertension). The group of animals with the arterial clip drank significantly less alcohol and more water than a sham-operated group. The two groups, however, drank similar amounts of a palatable glucose solution, suggesting that they did not differ in taste sensitivity. Blood alcohol levels measured for six hours following a 2.5 g/kg intraperitoneal injection of alcohol indicated that the difference in alcohol consumption between the two groups could not be accounted for in terms of differences in drug disposition or metabolism. These findings provide an example of a previously unknown type of control which originates in the periphery and contributes to the regulation of voluntary alcohol drinking.

Alcohol Drinking↗
PubMed1987

The firstborn's adjustment to the birth of a sibling: a longitudinal assessment.

41 middle-class families were interviewed at 1 month prepartum and 1, 4, 8, and 12 months after the birth of a second child to assess the reaction and adjustment of firstborn children to this event. Family members were also observed in a semistructured play session in order to obtain information concerning changes in familial interaction patterns. A log linear analysis was conducted to fit a hierarchical model to a 2 (child gender) X 2 (infant gender) X 4 (time of measurement relative to birth of infant) X 2 (presence or absence of problematic regressive behavior) X 14 (type of problematic behavior reported) matrix. A model with 2 statistically significant effects was found to fit the observed frequency matrix quite well, goodness-of-fit (GF) chi 2(312, N = 2,296) = 97.47, p less than .99. This model suggests (1) that the type of response displayed by the firstborns varied as a function of time since the birth; that their initial responses were either imitations of the infant or confrontations with the mother or infant, whereas responses at 4 months postpartum were characterized by numerous anxiety behaviors but fewer imitations or confrontations, and later responses were primarily confrontations with the increasingly intrusive and independent infant; and (2) that a greater frequency of problematic behavior was reported by the mothers of same-sex sibling dyads, especially at the 1- and 8-month postpartum assessments. Observational data indicated that mothers dramatically decreased their interactions with the firstborn children over time but that fathers tended to remain relatively stable in their frequencies of interaction.

Adult↗
PubMed1987

Effect of thioridazine on phenytoin serum concentration: a retrospective study.

Serum phenytoin concentrations before and after the addition of thioridazine were retrospectively compared in 27 adults to determine if an interaction occurred between these two drugs. A change in the serum phenytoin concentration of +/- 4 micrograms/ml was considered clinically significant; by this definition four patients (14.8 percent) had an increase, two (7.4 percent) had a decrease, and most (77.8 percent) demonstrated no change. The mean difference was 0.8 microgram/ml +/- 3.7 micrograms/ml and was not found to be statistically significant (p less than 0.1). Clinically important alterations in phenytoin serum concentration as caused by thioridazine appear to be infrequent.

Adolescent↗
PubMed1987

Drug use in an ambulatory elderly population: a five-year update.

Drug usage was studied in an ambulatory elderly population in Dunedin, Florida. Prescription and nonprescription drug use in these 2834 participants was compared with use during a period five years earlier. The average number of medications increased from 3.2 in 1978-80 to 3.7 in 1983-85. The most commonly prescribed medications in this population were hydrochlorothiazide-triamterene (13.5 percent), digoxin (9.6 percent), and hydrochlorothiazide (8.4 percent). There was a large increase in the use of nutritional supplements in the past five years, with 18.0 percent of these subjects reporting the use of vitamin E and 15.7 percent taking vitamin C. The general philosophy in geriatrics is to use the fewest drugs possible; however, it appears that the elderly are, in fact, receiving an increasing number of medications.

Age Factors↗
PubMed1987

Clinical research in the elderly: ethical and methodological considerations.

Clinically oriented research in the elderly is of growing interest because of increasing numbers of older persons, the relative lack of research data with this population, and recent Food and Drug Administration mandates to study drugs in the elderly. Studies of young, healthy persons cannot necessarily be extrapolated to the elderly due to changes associated with aging and the increased number of concomitant disease states and medications. Subject recruitment may be more time consuming in finding subjects with the appropriate inclusion criteria and lack of exclusion criteria who are willing to participate. Additional concern must be placed on protecting the subject's rights while allowing autonomous decision making. Likewise, protocols may need to be flexible enough to include persons with concomitant disease and medications.

Aged↗
PubMed1987

Evaluation of gamma radiation levels for reducing pathogenic bacteria and fungi in animal sewage and laboratory effluents.

Sewage samples collected from animal wastes and from effluents at an animal disease laboratory were inoculated with known numbers of pathogenic organisms and subjected to various doses of gamma radiation from a 60Co source. Surviving test organisms were quantitatively determined by selective and enrichment techniques. The experiment was modeled as a quantal assay in which probit analysis was applied to obtain D10 values. The D10 value represents the irradiating dose required to reduce the population by 90%. The D10 value ranged from 13.4 krad for Campylobacter fetus to 156.6 krad for Streptococcus faecalis in animal sewage. However, the D10 value for the laboratory effluent was generally lower. Based on the estimated D10 values, the rating of the test organisms in decreasing order of radiosensitivity appeared as follows: Brucella abortus, Campylobacter fetus subsp. fetus, Campylobacter jejuni, Campylobacter coli, Campylobacter laridis, Mycobacterium fortuitum, Aspergillus fumigatus, Salmonella muenster, Candida albicans, Clostridium difficile and Streptococcus faecalis. If the D5 and D1 values were utilized, this listing would be only slightly altered.

Bacteria↗
PubMed1987

Immune response in skunks to a vaccinia virus recombinant expressing the rabies virus glycoprotein.

Striped skunks (Mephitis mephitis) were vaccinated with a vaccinia virus recombinant expressing the rabies virus glycoprotein. Virus neutralizing antibodies to rabies virus were present at 14 days postvaccination by the following routes: scarification (6/6), intramuscular (4/4) and intestinal (5/8). Six out of seven skunks that ate vaccine filled baits had virus neutralizing antibodies at 28 days. When challenged intramuscularly with street virus, the survival rates were 5/7 for the bait-fed group, 4/8 for the intestinal group, 3/4 for the intramuscular group, 5/6 for the animals that were scarified, and 0/8 for controls. This is the first report of a high rate of immunization of skunks with a rabies vaccine administered orally.

Animals↗
PubMed1987

The clinical pharmacist in drug research and development. Pharmacoepidemiology.

From the inception of drug monitoring research programs, pharmacists have played a key role in their design and implementation. As greater emphasis is placed on the value of these data bases, pharmacists will be increasingly called upon to conduct epidemiologic studies. Formalized training in the principles of epidemiology and biostatistics will allow pharmacists to expand their role in this important area of research.

Drug Industry↗
PubMed1986

Voluntary alcohol intake in the hypertension prone Dahl rat.

Previous work in our laboratory has shown that alterations in the sodium content of the diet which alter salt appetite, can modify ethanol self-selection and intoxication. The present experiment investigates the relationship between the intakes of sodium and ethanol on the one hand and the development of hypertension, by measuring voluntary ethanol consumption and blood pressure in two rat lines, the salt sensitive (SS) and salt resistant (SR) Dahl rats, specially bred to show differential sensitivity to dietary sodium supplements. All rats were given 24 hr access to 6% (v/v) ethanol and water and first offered a control diet (0.5% Na) followed by a 4% and then an 8% sodium supplemented diet. While on the control diet there were significant between strain differences in ethanol consumption, suggesting that the SS animals came genetically prepared to consume more ethanol. Blood pressure measured at regular intervals indicated significant changes only in the SS rats even though both lines as well as a group of Wistar rats, added for purposes of comparison, all increased their ethanol intake to the salt supplemented diets. A second experiment suggested that the initial difference in consumption between the SS and SR lines may be related to central nervous system sensitivity since differences were found in salt appetite but not in taste sensitivity or in the absorption, distribution or metabolism of the drug. These findings demonstrate that the Dahl SS rat is predisposed to consume more ethanol than the SR rat even before exposure to the hypertension-inducing diet, and that this predisposition is probably central in origin.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohol Drinking↗
PubMed1986

Conditioned place aversion mediated by orally self-administered ethanol in the rat.

The hypothesis was tested that ethanol, self-administered via the oral route, would mediate a conditioned preference for the environment in which the drug was consumed. Ten rats were trained to drink an 8% (weight/volume) ethanol solution in association with one environment and had a different environment paired with the availability of water. Ten control animals had only water available in both environments. The experimental animals drank more ethanol solution than water and achieved doses in excess of their metabolic capacity as confirmed by blood ethanol levels. The drug was functioning as a positive reinforcer, yet the rats avoided the environment in which ethanol was consumed, indicating aversive properties of the drug. The control animals showed no change in preference for the environments associated with water. The conditioned place aversion observed was in accordance with previous studies in which rats were passively dosed using non-oral routes of administration but was paradoxical since the ethanol was actually self-administered.

Alcohol Drinking↗
PubMed1986

Symptom prevalence in the elderly. An evaluation of age, sex, disease, and medication use.

Prevalence of reported symptoms was studied in 1927 women and 1140 men over 65 years of age in an ambulatory health screening program. Reports of 28 common symptoms were obtained from a standardized questionnaire completed by participants at the time of their fourth annual visit to the program. A comparison was made of the prevalence of specific symptoms by sex, age, disease states, and drug use patterns. The most common symptoms reported by women were nocturia (80.4%), swollen feet or ankles (30.5%), cold feet and/or legs (28.6%), and irregular heartbeat (23.2%), whereas men complained most often of nocturia (79.8%), irregular heartbeat (24.8%), cold feet and/or legs (23.6%), and tinnitus (23.1%). Women reported a mean of 3.99 symptoms compared with 3.22 reported by men (P less than .0001). In women their was a statistically significant association for most symptoms in subjects reporting the use of medication compared with a group who did not use medication. In men the use of medication was less highly correlated with reports of symptoms. Nearly 100% of participants reported having at least one disease state. The number of symptoms reported was strongly related to the number of disease states, and after adjusting for diseases, women reported more symptoms than men. The best predictor of symptom prevalence was the number of disease states followed by the number of drugs used and then age.

Age Factors↗
PubMed1986

Catheter-mediated electrical ablation: the relation between current and pulse width on voltage breakdown and shock-wave generation.

Barotrauma from arc induced shock waves may result in dangerous sequelae during ablation of arrhythmogenic foci. In this report, maximum pulse amplitude and pulse width determinations were made to assess avoidance of shock-wave generation using rectangular constant current pulses. Energy delivery appears to be optimal between 80-100 microseconds. If higher energies are required, multiple pulses will be needed to avoid barotrauma.

Animals↗
PubMed1986

Isolation and characterization of cephalothin-susceptible Campylobacter coli from slaughter cattle.

In a recent meat survey, 10 of 13 (77%) Campylobacter coli isolates were susceptible to cephalothin. These organisms were isolated from nine slaughter cattle from eight meat packing establishments. All 10 isolates grew at 43 degrees C but not at 25 degrees C, were catalase and oxidase positive, and were susceptible to nalidixic acid (30 micrograms) and cephalothin (30 micrograms). The cultures were subsequently identified as C. coli serogroup 20, biotype I (Lior scheme). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that protein and lipopolysaccharide profiles of whole cell preparations of the 10 cephalothin-susceptible strains and the reference strain for C. coli serogroup 20 were very similar. The plasmid profiles of these 11 strains were identical.

Abattoirs↗
PubMed1986

Wide complex tachycardia: misdiagnosis and outcome after emergent therapy.

The extent and consequence of misdiagnosis of wide complex tachycardia (QRS, 120 ms or more; heart rate, 100 or more beats/min) presenting emergently were assessed. Forty-six consecutive episodes of wide complex tachycardia were reviewed and their tachycardia mechanisms subsequently established. All 8 episodes of supraventricular tachycardia with aberrant conduction were correctly diagnosed, whereas 15 of 38 episodes of ventricular tachycardia (39%) were misdiagnosed as supraventricular tachycardia at the time initial therapy was given. Ventriculoatrial dissociation was evident in 11 (73%) of the electrocardiograms of misdiagnosed ventricular tachycardia. Patients with misdiagnosed episodes had poorer outcomes than those with episodes correctly diagnosed (p = 0.0003). Verapamil was administered to patients in 13 of the 15 episodes of misdiagnosed ventricular tachycardia; hemodynamic deterioration occurred in all 13 episodes. Wide complex tachycardia is often incorrectly diagnosed as supraventricular tachycardia when, in fact, the 12-lead electrocardiogram strongly suggests ventricular tachycardia. Verapamil is commonly administered in these circumstances and is frequently associated with a poor outcome.

Adolescent↗
PubMed1986

Vitamin E effect on symptoms and laboratory values in the elderly.

The effect of vitamin E use on selected medical disorders and laboratory parameters was studied in a large ambulatory elderly population. Information obtained from a standardized questionnaire concerning reports of numerous clinical disorders, such as hypertension, fatigue, and vaginal bleeding, was used to determine whether the use of vitamin E predisposed to those conditions. During a 2-year period, information was available on 369 vitamin E users and 1,861 non-users. No differences were noted in the prevalence of reported clinical disorders between the two groups, except that men using vitamin E complained more often of shortness of breath (p less than .04) and angina (p less than .03). There were no significant differences between vitamin E users and controls in any hematologic parameters studied. After the groups had been adjusted for age and sex differences, only one biochemical parameter, serum glutamic-oxaloacetic transaminase (SGOT) in men, was found to be significantly different in vitamin E users as compared with controls. Use of vitamin E by the participants in this study appeared to have little influence on clinical disorders or hematologic or biochemical parameters.

Aged↗