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Biomedical subjects

H Brown

Publications and source records attributed to H Brown.

At least 127 records · Page 7Linked to original sources
PubMed1991

Personality. Type A behavior, and the effects of beta-blockade.

In a previous report, it was shown that a dimension of personality entitled dependence/independence could be used to distinguish the cardiovascular and catecholaminergic response to stress in type A individuals. This study is a continuation of the previous work. It examines the relative effects of beta-blockade on stress-induced changes in heart rate, blood pressure, and catecholamines in two groups of type A individuals who differ in reactivity. Sixty-six healthy, middle-aged men with type A behavior were classified as dependent (high reactivity) or independent (low reactivity). The effects of beta-blockade on the two groups were tested in a randomized, double-blind, crossover trial utilizing a mental stressor, a physical stressor, and work day monitoring. Results showed that, in comparison with the independent type As, those who had been classified as dependent had higher heart rates in all three stress conditions and had higher epinephrine levels during both the mental and physical stressors. For both groups, beta-blockade lowered the heart rate and systolic blood pressure but increased norepinephrine with the mental stressor and epinephrine and norepinephrine with the physical stressor. It also reduced the mean work day heart rate. For the dependent type As, the drug had a greater effect on increasing epinephrine during the physical stressor and by reducing the percent of the work day spent in high heart rate zones. The results are discussed from the point of view of identifying type As who may be particularly coronary prone and the potential effects of beta-blockade on the reactivity associated with type A behavior.

Adult↗
PubMed1991

Antibiotic treatment and associated prolonged prothrombin time.

The incidence and type of pathology causing a prolonged prothrombin time and clinical bleeding episodes were assessed in a multicentre study of 1109 patients receiving cefotetan, a N-methyl-thiotetrazole (NMTT), or equivalent antibiotics. There was no significant difference in the incidence of a prolonged prothrombin time (9.9% with cefotetan, 8.0% with comparable antibiotics) of clinical bleeding episodes. However, prothrombin time increases of greater than 12 seconds were significantly (p = 0.002) greater with cefotetan (3.8%) than with comparators (0.8%). In both antibiotic groups increases in prothrombin time were more likely following surgery and in patients who were older, with a high platelet count, low albumin, or higher urea and creatinine concentrations. All antibiotic treatment can be associated with prolonged prothrombin times and new agents should always be assessed in a large multicentre study before the practical, clinical importance of haemostatic defects can be defined.

Adolescent↗
PubMed1991

Basic medical physiology: the whole is more than the sum of its parts.

In this article we examine the role of basic medical physiology in medical school education. We discuss the historical background, courses in this subject, and methods of teaching it. We conclude that the teaching of medical physiology should emphasize the study of organ systems and of the intact body. The techniques should emphasize meticulous observation, the posing of hypotheses, and the subsequent testing of the hypotheses, i.e., the use of the method used successfully in research. Students should learn the power of the experimental approach and to appreciate the immense variability possible in responses in complex organisms. They should also learn that principles of statistical probability applied logically can detect important differences in data that may be obscured by this variability. They should learn that there are no rigid answers when studying an individual and that they must continue to learn throughout their lives.

Animals↗
PubMed1989

Temazepam withdrawal in elderly hospitalized patients: a double blind randomised trial comparing abrupt versus gradual withdrawal.

31 of 36 elderly mainly confused hospitalized patients (69-98 years) taking temazepam 10 mgs nocte for more than one month completed a double blind randomised placebo controlled trial comparing abrupt versus gradual withdrawal of temazepam. Hours of sleep were recorded for all patients during a 7 day baseline period while taking temazepam 10 mg nocte. Then the abrupt withdrawal (AW) group (n = 15) received placebo for 10 nights and the gradual withdrawal (GW) group (n = 16) received temazepam 5 mg for the first 4 nights, 2 mg for the next 4 nights and placebo for the last 2 nights. There was no significant difference in mean hours of nightly sleep during the baseline period between the AW group (5.9 +/- 1.1 SD) and GW group (5.8 +/- 1.1 SD) and between the baseline and withdrawal periods in each group (withdrawal periods, AW 5.6 +/- 1.2, GW 5.6 +/- 1.0). There was no rebound insomnia when temazepam was withdrawn either abruptly or gradually in long-term hospitalised elderly patients and may not be effective as a long-term hypnotic.

Aged↗
PubMed1989

Responses of left and right ventricular ejection fractions to aerobic and anaerobic phases of upright and supine exercise in normal subjects.

The effects of aerobic and anaerobic exercise on ventricular performance were studied in 13 normal subjects who underwent simultaneous pulmonary gas exchange evaluation and exercise radionuclide ventriculography in the supine and upright postures. Right and left ventricular ejection fraction was measured serially at 2-minute intervals during exercise. The anaerobic threshold occurred at 74% and 80% of maximum heart rate, respectively, during upright and supine exercise. Left and right ventricular ejection fractions rose from rest to the anaerobic threshold (p less than 0.01, p less than 0.01, respectively) and there was a further increase between the anaerobic threshold and maximum exercise (p less than 0.01, p less than 0.01, respectively). The rate of rise of ejection fraction beyond the anaerobic threshold was slightly blunted compared with the rise prior to attaining the anaerobic threshold. There was no significant difference in ventricular performance between supine and upright exercise. The data demonstrate that ventricular performance increases steadily during exercise and is not limited by the conversion of aerobic to anaerobic metabolism.

Adult↗
PubMed1988

The spinal accessory nerve plexus, the trapezius muscle, and shoulder stabilization after radical neck cancer surgery.

A clinical and anatomic study of the spinal accessory, the eleventh cranial nerve, and trapezius muscle function of patients who had radical neck cancer surgery was conducted. This study was done not only to document the indispensibility of the trapezius muscle to shoulder-girdle stability, but also to clarify the role of the eleventh cranial nerve in the variable motor and sensory changes occurring after the loss of this muscle. Seventeen male patients, 49-69 years of age, (average of 60 years of age) undergoing a total of 23 radical neck dissections were examined for upper extremity function, particularly in regard to the trapezius muscle, and for subjective signs of pain. The eleventh nerve, usually regarded as the sole motor innervation to the trapezius, was cut in 17 instances because of tumor involvement. Dissection of four fresh and 30 preserved adult cadavers helped to reconcile the motor and sensory differences in patients who had undergone loss of the eleventh nerve. The dissections and clinical observations corroborate that the trapezius is a key part of a "muscle continuum" that stabilizes the shoulder. Variations in origins and insertions of the trapezius may influence its function in different individuals. As regards the spinal accessory nerve, it is concluded that varying motor and sensory connections form a plexus with the eleventh nerve, accounting, in part, for the variations in motor innervation and function of the trapezius, as well as for a variable spectrum of sensory changes when the eleventh nerve is cut. For this reason, it is suggested that the term "spinal accessory nerve plexus" be used to refer to the eleventh nerve when it is considered in the context of radical neck cancer surgery.

Accessory Nerve↗
PubMed1987

Sequence variation in S-antigen genes of Plasmodium falciparum.

S-antigens are soluble heat-stable antigens released into the circulation at the time of schizogony of Plasmodium falciparum. Many serologically distinct S-antigens exist and we have shown that this diversity results from repetitive sequences that vary in repeat number, length, sequence and/or reading frame among different S-antigens. We present here the complete sequence of the S-antigen of a Vietnamese isolate V1. The major repeat of 33 base-pairs can be considered to be derived by a deletion event from a 45 base-pair sequence that is located at the 3' repeat boundary and is related in sequence to all S-antigen repeats known so far. We also show that the non-repetitive coding region of the S-antigen gene of V1 is identical to that of K1 and only two amino acids different to that of NF7. In contrast, the sequences are considerably different to those of the FC27 and Wellcome isolates. We conclude that S-antigen genes are highly polymorphic in the repetitive regions but show more restricted diversity in non-repetitive regions.

Amino Acid Sequence↗