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Biomedical subjects

B Brown

Publications and source records attributed to B Brown.

At least 235 records · Page 13Linked to original sources
PubMed1988

Evaluation of applied potential tomography as a new non-invasive gastric secretion test.

Applied potential tomography (APT) is a new, non-invasive technique that can yield sequential images of changes in the resistivity of gastric contents. Studies were performed to investigate the application of APT to measure gastric acid secretion. Experiments in 20 normal volunteers showed that changes in gastric resistivity were closely correlated with changes in the volume (r = 0.80), the acidity (r = 0.83) and the total conductivity of gastric contents (r = 0.87). Studies in 13 patients referred for a pentagastrin test showed that changes in gastric resistivity before pentagastrin were closely correlated with basal acid output measured on a separate occasion (r = 0.85, p less than 0.001), while changes in gastric resistivity after pentagastrin were correlated with maximal acid output (r = 0.58, p less than 0.05). Ingestion of alcohol by six normal subjects decreased gastric resistivity markedly, probably due to alcohol induced gastric acid secretion as it was prevented by cimetidine. Applied potential tomography is a safe non-invasive method of measuring gastric acid secretion. The equipment is simple to use, and the test is comfortable and acceptable to patients.

Adolescent↗
PubMed1988

Medical evacuations from offshore structures.

A retrospective study was carried out on medical evacuations from the installations of four major oil or gas producing companies, or both, operating offshore on the United Kingdom continental shelf. The study covered 1976-84 during which 2162 evacuations were recorded. Of these, 137 (7.7%) required the use of a chartered helicopter. In the earlier years of the study there were substantially more injuries sustained than episodes of illness recorded but from 1980 onwards the cases of illness equalled those of injury. Using the International Classification of Diseases, the digestive system was responsible for most evacuations for illness and of those, about half (115 evacuations) were for dental problems. Suspected fractures were responsible for about one third of those evacuated for an injury but injuries of hands and eye conditions were particularly common, accounting for 25% of all evacuations. As the age of the evacuee increased the proportion of evacuations for injury decreased and that for illness increased. The mean age for evacuation for injury was 28.3 years and for illness 34.4 years. Few evacuations were required for those aged over 45.

Accidents, Occupational↗
PubMed1988

Reflex effect of skeletal muscle mechanoreceptor stimulation on the cardiovascular system.

To determine the potential for mechanical stimulation of skeletal muscle to contribute to the reflex cardiovascular response to static contraction (exercise reflex), we examined the cardiovascular effects caused by either passive stretch or external pressure applied to the triceps surae muscles. First, the triceps surae were stretched to an average developed tension of 4.8 +/- 0.3 kg. This resulted in increases in mean arterial pressure (MAP) of 28 +/- 7 mmHg, dP/dt of 1,060 +/- 676 mmHg/s, and heart rate (HR) of 6 +/- 2 beats/min (P less than 0.05). Additionally, increments of 0.3, 0.5, 1.0, 2.0, 4.0, and 8.0 kg of tension produced by passive stretch elicited pressor responses of -6 +/- 1, 7 +/- 1, 16 +/- 3, 21 +/- 8, 28 +/- 6, and 54 +/- 9 mmHg, respectively. External pressure, applied with a cuff to the triceps surae to produce intramuscular pressures (125-300 mmHg) that were similar to those seen during static contraction, also elicited small increases in MAP (4 +/- 1 to 10 +/- 1 mmHg) but did not alter HR. Transection of dorsal roots L5-L7 and S1 abolished the responses to passive stretch and external pressure. Moreover, when the triceps surae were stretched passively to produce a pattern and amount of tension similar to that seen during static hindlimb contraction, a significant reflex cardiovascular response occurred. During this maneuver, the pressor response averaged 51% of that seen during contraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Afferent Pathways↗
PubMed1988

Influence of underlying disease process on the utility of cellulitis needle aspirates.

A prospective microbiological evaluation of 87 patients with acute cellulitis was performed. Adult patients with cellulitis with diabetes mellitus or malignant disorders had a greater frequency of positive cultures. Qualitative leukocyte disorders associated with these underlying disease states was hypothesized as a contributing factor to this higher yield.

Acute Disease↗
PubMed1988

Fluctuations in intra-ocular pressure with sleep: I. Time course of IOP increase after the onset of sleep.

Ten normal subjects slept over a series of four nights for time periods of 30 minutes, 1, 2 and 4 hours. Intra-ocular pressure (IOP) measurements were made using a non-contact tonometer before and after sleep. The subjects showed a significant increase in IOP of 3.45 mm Hg after 30 minutes of sleep and a further IOP increase thereafter to 6.41 mm Hg above baseline. Such increases in IOP after sleep in normal subjects suggest that glaucoma patients and those suspected of having glaucoma should be monitored overnight to assess their IOP control mechanisms.

Data Interpretation, Statistical↗
PubMed1987

Chromosome aberrations and sister chromatid exchanges in Chinese hamster ovary cells: evaluations of 108 chemicals.

Results from the testing of 108 coded chemicals in Chinese hamster ovary (CHO) cells for the induction of chromosome aberrations and sister chromatid exchanges (SCEs) are presented. All chemicals were tested with and without exogenous metabolic activation, using protocols designed to allow testing up to toxic doses. Cell harvest times could also be extended if chemical-induced cell cycle delay was seen. Chromosome aberrations were induced by 43 of the chemicals, and 66 induced SCEs; 37 of the chemicals were positive for both endpoints.

Animals↗
PubMed1987

Effect of discontinuance of type A behavioral counseling on type A behavior and cardiac recurrence rate of post myocardial infarction patients.

Three hundred post infarction participants who had received type A behavioral counseling in the Recurrent Coronary Prevention Project, (RCPP) agreed to be followed for 1 additional year after stopping 4.5 years of continuous type A behavioral counseling. One hundred fourteen participants who had served for 4.5 years as controls in the RCPP Study, thus receiving no type A behavioral counseling, volunteered to receive such counseling for 1 year. Eleven of the 300 previously type A counseled RCPP participants were lost to follow-up at the end of the additional year. The remaining 289 subjects at risk were found to have maintained their previously reduced intensity of type A behavior. Their previously observed relatively low cardiac recurrence rate during the additional year also did not significantly change. Ten of the 114 previous control RCPP participants were lost to follow-up at the end of the additional year. The remaining 104 subjects who had received a year's type A behavioral counseling showed a significantly reduced intensity of type A behavior and a similar significant decrease in both the cardiac mortality and morbidity rate. These results suggest that the decline in the intensity of type A behavior and also in the cardiac recurrence rate previously observed in post infarction subjects exposed to type A behavioral counseling persists for at least 1 year after cessation of such counseling.

Counseling↗
PubMed1987

Surgery on the hemophiliac patient. Special considerations.

Optimum care of patients with hemophilia requires cooperation among the hematologist, the surgeon, nurses, and blood bank personnel. Relatively normal hemostasis can be achieved and maintained in factor-deficient individuals in the perioperative period. Surgical procedures in patients with hemophilia can be accomplished safely with careful monitoring of coagulation factor levels and appropriate replacement therapy.

Factor VIII↗
PubMed1987

Sensitivity to changes in size and velocity in young and elderly observers.

Thresholds for detection of change of size and for detection of change of velocity were measured in young and elderly observers. No differences in thresholds between these subject groups were found at the fovea or in more peripheral retina. The results indicate a degree of functional redundancy in the peripheral retina of elderly subjects, even though there is evidence of reduced numbers of functional photoreceptors in the periphery.

Adolescent↗
PubMed1987

Diurnal variation of intraocular pressure and the overriding effects of sleep.

Intraocular pressure (IOP) was recorded regularly over a 24-h period in 13 normal subjects. All subjects showed a dramatic rise in IOP after sleep, ranging from 37 to 248%. In a second experiment, IOP decreased when 15 subjects remained upright and awake throughout the night. When sleep was not permitted IOP was lowest at 3:00 a.m. (0300); when six of these subjects were permitted to sleep from 0600 to 0800, they showed a rapid and significant increase in IOP of up to 150%, whereas the remaining nine subjects showed (posturally induced) increases of up to 38%.

Adolescent↗
PubMed1987

Effects of the bogus-pipeline on enhancing validity of self-reported adolescent drug use measures.

This study examined effects of a bogus objective measure (bogus-pipeline) on self-reports of experimentation, frequency, intentions, beliefs, and attitudes related to alcohol, tobacco, and other drug use. One hundred ninety-one adolescents (means age = 11.74 years) were assigned randomly to one of three conditions: a bogus-pipeline with saliva collection, a bogus-pipeline only, or a questionnaire only control. A significantly greater percentage of participants in the questionnaire only condition (28%) reported having experimented with alcohol, compared to those in the bogus-pipeline only condition (22%), and the bogus-pipeline with saliva condition (21%). No differences were found across conditions for subject experimentation with other drugs, frequency of drug use, intentions to use drugs, and beliefs and attitudes related to drug use (p greater than .05). The discrepancy among studies suggesting a validity enhancing effect due to bogus-pipeline procedures and those indicating no effect may be accounted for by variables including age, experimental setting, population under study, and drug types. The broad, unquestioned application of the bogus-pipeline in tobacco, alcohol, and other drug use prevention programs, or epidemiological studies of drug use, cannot be recommended at present.

Adolescent↗
PubMed1986

The effects of antihypertensive therapy on the quality of life.

We conducted a multicenter randomized double-blind clinical trial among 626 men with mild to moderate hypertension to determine the effects of captopril, methyldopa, and propranolol on their quality of life. Hydrochlorothiazide was added if needed to control blood pressure. After a 24-week treatment period, all three groups had similar blood-pressure control, although fewer patients taking propranolol required hydrochlorothiazide. Patients taking captopril alone or in combination with a diuretic were least likely to withdraw from treatment because of adverse effects (8 percent vs. 20 percent for methyldopa and 13 percent for propranolol). The treatment groups were similar in scores for sleep dysfunction, visual memory, and social participation. However, patients taking captopril, as compared with patients taking methyldopa, scored significantly higher (P less than 0.05 to less than 0.01) on measures of general well-being, had fewer side effects, and had better scores for work performance, visual-motor functioning, and measures of life satisfaction. Patients taking propranolol also reported better work performance than patients taking methyldopa. Patients taking captopril reported fewer side effects and less sexual dysfunction than those taking propranolol and had greater improvement (P less than 0.05 to less than 0.01) on measures of general well-being. Our findings show that antihypertensive agents have different effects on the quality of life and that these can be meaningfully assessed with available psychosocial measures.

Adult↗
PubMed1986

Alteration of type A behavior and its effect on cardiac recurrences in post myocardial infarction patients: summary results of the recurrent coronary prevention project.

One thousand thirteen post myocardial infarction patients were observed for 4.5 years to determine whether their type A (coronary-prone) behavior could be altered and the effect such alteration might have on the subsequent cardiac morbidity and mortality rates of these individuals. Eight hundred sixty-two of these individuals were randomly assigned either to a control section of 270 participants who received group cardiac counseling or an experimental section of 592 participants who received both group cardiac counseling and type A behavioral counseling. The remaining 151 patients, serving as a "comparison group," did not receive group counseling of any kind. Using the "Intention-to-Treat" principle, we observed markedly reduced type A behavior at the end of 4.5 years in 35.1% of participants given cardiac and type A behavior counseling compared with 9.8% of participants given only cardiac counseling. The cumulative 4.5-year cardiac recurrence rate was 12.9% in the 592 participants in the experimental group that received type A counseling. This recurrence rate was significantly less (p less than 0.005) than either the recurrence rate (21.2%) observed in the 270 participants in the control group or the recurrence rate (28.2%) in those of the comparison group not receiving any special treatment. After the first year, a significant difference in number of cardiac deaths between the experimental and control participants was observed during the remaining 3.5 years of the study. Overall, the results of this study demonstrate for the first time, within a controlled experimental design, that altering type A behavior reduces cardiac morbidity and mortality in post infarction patients.

Behavior Therapy↗
PubMed1986

Relative levels of thecal blood flow in atretic and non-atretic ovarian follicles of the conscious sheep.

The relative level of blood flow through thecal capillaries (RTF) in individual atretic and non-atretic follicles greater than 1 mm was measured in conscious ewes by injecting 15 micron radioactive microspheres into the aorta near the origin of the ovarian artery, and determining the ratio of radioactivity per mg protein in theca of individual follicles to that in the non-luteal portion (stroma plus follicles less than 1 mm diameter) of the corresponding ovary. In follicles greater than 1 mm diameter, RTF in those showing advanced stages of atresia (stages IV and V) was significantly less than that in non-atretic (stage I) follicles. RTF values in non-atretic (stage I), early atretic (stage II) and moderately atretic (stage III) follicles did not differ significantly. There was no effect of follicular diameter (P greater than 0.05) on the relative level of blood flow within individual thecae or of atresia on thecal protein content. These data indicate that reduced thecal blood flow is associated with advanced atresia of antral follicles and are in accordance with the findings of previous histological studies. Whether thecal ischaemia is a factor involved in the onset of atresia, or occurs as a consequence of the degenerative process, remains uncertain.

Animals↗
PubMed1986

On death and dying.

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Attitude of Health Personnel↗
PubMed1986

Reaction times to edges of variable sharpness in age-related maculopathy.

An experiment was conducted to measure reaction times to edges of varying sharpness profiles presented on an oscilloscope in aged normals, subjects with age-related maculopathy (ARM), and subjects who had 6/6 acuity with drusen and/or pigmentary changes visible ophthalmoscopically, i.e., subjects at risk of developing ARM. Mean reaction time increased with decreased sharpness of the edge profiles for all groups tested. In subjects with ARM there was a further increase in mean reaction time of up to 20% for all edge profiles. In the group at risk of developing ARM there was a small but significant increase in mean reaction time for all edge profiles. It appears that there are measurable functional deficits in subjects whose acuity is normal but who show signs of developing ARM. This performance decrement may be important in the recognition of signs and signals in the driving environment, inasmuch as edge sharpness has been identified as an important component of sign conspicuity.

Aged↗