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Biomedical subjects

J Reid

Publications and source records attributed to J Reid.

At least 217 records · Page 12Linked to original sources

Atrioventricular sequential pacing: comparison with ventricular pacing using systolic time intervals.

Nine patients with programmable atrioventricular sequential pacers were studied using systolic time intervals (QS2--the total electrical and mechanical systole, left ventricular ejection time, and pre-ejection period). These measurements were obtained by simultaneous recording of the electrocardiogram, phonocardiogram, and carotid pulse tracing. There was a dramatic fall of left ventricular ejection time (LVET) and an increase of the pre-ejection time (PEP) in all patients when the pacers were programmed from the atrioventricular to the ventricular mode at constant heart rate. This resulted in an increase of the ratio PEP/LVET from .428 to .574 suggesting loss of ventricular function. These measurements all reversed to baseline values when the pacers were re-programmed back to the atrioventricular mode. This study suggests systolic time intervals might be useful to select non-invasively pacer parameters such as mode, rate, and effective PR interval in order to provide the best hemodynamics in a given patient.

Aged↗

Educating mothers: how effective are MCH clinics?

Detailed records were kept of interactions between nurses, mothers and children at 18 child health clinics run from six centres in Madang Province, Papua New Guinea. The time spent with mother and child was rarely more than two minutes. Family planning advice was given to only one mother and nutrition advice to mothers of one-quarter of the underweight children. Most of the time was spent weighing, examining and treating children. Nurses of these teams clearly give low priority to nutrition and family planning education. This is the result of several factors. These include the way clinics are organized, the structure of the health service and the attitudes and motivation of nurses. One way of promoting the preventive and educational role of clinics would be to make them problem-oriented, focusing on at-risk families rather than individual children. This would help nurses to set goals and to see the rewards of their work.

Child↗

The cardiovascular effects of centrally administered substance P in the anaesthetised rabbit.

The cardiovascular effects of Substance P (SP) administered into the cisterna magna (i.c.) of the pentobarbitone anaesthetised rabbit have been investigated. SP given i.c. in low doses (0.2-10 ng/kg) caused a dose related rise in blood pressure and bradycardia. Both responses were attenuated by pretreatment with intravenous (i.v.) pentolinium. SP given i.v. (1 ng/kg-1 microgram/kg) caused a dose related fall in pressure and tachycardia. The pressor response observed after i.c. administration was reduced by pretreatment with morphine and enhanced by naloxone. Bilateral sinoaortic denervation also enhanced the pressor effect of SP, but after deafferentation naloxone had no further effect. Pretreatment with clonidine abolished this rise in pressure. It is concluded that the central administration of SP has a direct pressor effect whereas the bradycardia appears to result from both direct and indirect effects, leading to a decrease in cardiac sympathetic activity. Both actions are mediated by the autonomic nervous system. SP may be involved in the central regulation of blood pressure and modulation of baroreceptor reflex activity.

Anesthesia↗

Recovery in vivo and in vitro of alpha-adrenoceptor responses and radioligand binding after phenoxybenzamine.

Phenoxybenzamine is an irreversible, selective alpha 1-adrenoceptor antagonist that results in long-lasting attenuation of the effects of alpha-adrenoceptor agonists in vivo and in vitro. We have studied in rabbits the time course of recovery of in vivo pressor responses to phenylephrine and in vitro contractile responses of spiral strips of renal artery to phenylephrine and noradrenaline. The maximum number of binding sites and the dissociation constant has been determined using 3H-prazosin in spleen and heart membranes prepared at intervals up to 8 days after phenoxybenzamine 5 mg/kg intravenously. In vitro contractile responses recovered over 2-3 days and by 4 days the EC50 was lower than control. In vivo pressor responses recovered over 5-8 days to control levels. The number of binding sites was only 50% of control at 8 days. It is proposed that under the conditions studied the recovery of binding sites may provide an index of turnover of alpha-adrenoceptors. The results also suggest that postreceptor mechanisms contribute to the increased responses observed in vitro.

Animals↗

Gastric emptying of solids in man.

The influence of the type and size of solid particles on their emptying from the stomach was studied using isotopically labelled chicken liver and inert particles in normal subjects and in patients who had undergone gastric surgery. In normal subjects, initial emptying of the liver was slower than that of inert particles both for large liver cubes (1 cm) and small cubes (0.3 cm). Liver emptying subsequently accelerated to be faster than emptying of the inert particles. Overall emptying of the liver given as small cubes was faster than large cubes; 50% emptied in 50 minutes and 70 minutes respectively. In the postoperative subjects, emptying of the liver and of the inert particles was identical. The findings are consistent with the hypothesis that solid foods such as liver are ground down and 'liquified' by the action of gastric peristalsis before being discharged to the duodenum. Ingested particle size appears to influence the rapidity of this process, which should be distinguished from the propulsive function of the stomach where small solid particles are concerned.

Adult↗

Cytostasis of tumor cell lines by granulocytes from cancer patients and normal human donors.

Granulocytes of normal human donors were previously shown to have cytostatic activity in vitro against a variety of tumor cell lines. In the present study, we have compared the levels of granulocyte-mediated cytostatic activity in cancer patients and normal donors. In an initial study of 25 tumor-bearing patients and 21 individuals with benign or no disease, decreased cytostatic activity was observed in 84% of the cancer patients. Nine cancer patients with no evidence of disease had reactivity in the normal range. Granulocytes separated by a one-step method on a double Ficoll-Percoll gradient showed decreased reactivity. This procedure eliminated the differences previously detected between tumor-bearing patients and controls. Addition of either pooled normal AB human serum or autologous serum to the assay restored the reactivity. Only with autologous serum and not with allogeneic serum, were the differences between tumor-bearing patients and controls again seen. Therefore, in a subsequent study, we examined the effect of serum on cytostasis by normal granulocytes that were isolated on double gradients. We observed lowered serum restorative activity (SRA) in 41 of the 46 (89%) tumor-bearing patients tested. Fractionation of sera by Sephadex G-200 chromatography indicated that SRA of both cancer patients and normal donors was in the 100,000 molecular weight region.

Breast Neoplasms↗

The glyceryl [14C]tripalmitate breath test: a reassessment.

Several reports have been published commending the use of 14C-labelled triglyceride breath tests in the assessment of fat malabsorption. We report further studies using gyceryl [14C]tripalmitate. Corrections for age, weight or metabolic rate failed to improve the test's ability to discriminate between malabsorbers and control subjects. A correction for respiratory quotient improved the linear correlation observed between the breath test results and daily faecal fat excretion. The significance of these findings is discussed and a number of problems identified which, at present, are preventing the introduction of breath tests for fat malabsorption into routine clinical practice.

Adult↗

Association of depressed postoperative lymphoproliferative responses to alloantigens with poor prognosis in patients with stage I lung cancer.

Thirty-five patients with Stage I carcinoma of the lung were tested postoperatively to assess lymphoproliferative responses. Depressed lymphocyte proliferation (LP) responses to alloantaigen in the mixed leukocyte culture (MLC) as measured by thee relative proliferation index (RPI) were associated with a significantly shorter disease-free interval. In this group of patients, the immunologic responses predicted subsequent clinical course better than the TNM classification or the histological type of the tumor, and therefore this procedure appears promising for improved staging of patients with early stages of lung cancer (stage I lung cancer and T1N0M0). The depressed response to alloantaigen was a more sensitive discriminator of disease recurrence than PHA alone or even conbined with PHA.

Adenocarcinoma↗

Benign gastric ulceration in pernicious anemia.

Benign gastric ulceration occurred in a patient with pernicious anemia in association with aspirin therapy. Previous reports of benign gastric ulceration in patients with achlorhydria are reviewed, and the potential role of aspirin in the pathogenesis of benign ulceration in the absence of acid is discussed.

Achlorhydria↗

Raynaud's phenomenon induced by sulphasalazine.

Sulphasalazine-induced Raynaud's phenomenon is reported in a patient who showed no other features of a drug-induced lupus syndrome. The vascular disturbance disappeared when the drug was withdrawn on 3 occasions. A simple technique for assessing the circulatory abnormality in Raynaud's phenomenon is described.

Adult↗

A comparative study of automated blood pressure recorders.

Four automated blood pressure machines (Arteriosonde 1225, Bosomat 11D, Elag Koln BE 237R and Omron HEM 3) have been compared with each other and with the Hawksley Random Zero Sphygmomanometer in 18 subjects with a wide range of BP. Each form of measurement provided a high degree of internal consistency. The Arteriosonde 1225 consistently recorded systolic and diastolic pressures which were below the values obtained with the Random Zero instrument (P=0.001). The other 3 automated machines recorded BPs which did not differ significantly from the Random Zero or from each other. Heart rate readings did not differ significantly for any of the machines compared to manual recording. The disparity attributable to the Arterisonde could result from its being the only form of measurement to use an ultrasonic rather than a microphonic recording technique. However, the cheaper and more portable automated machines produce results which closely reflect those obtained by using a mercury sphygmomanometer.

Blood Pressure Determination↗