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Biomedical subjects

K Jennings

Publications and source records attributed to K Jennings.

At least 73 records · Page 4Linked to original sources
PubMed1985

19F NMR spectroscopy study of the metabolites of flucloxacillin in rat urine.

19F NMR spectroscopy was used to monitor the metabolites of flucloxacillin in the urine of a rat dosed with its sodium salt. 19F NMR signals were detected and quantified from flucloxacillin and three metabolites. The 19F NMR method involves minimal sample preparation and is free from interference by endogenous urine components. High-field spin-echo 1H NMR spectroscopy and HPLC were used to confirm the results.

Animals↗
PubMed1984

Role of exercise testing early after myocardial infarction in identifying candidates for coronary surgery.

It has been suggested that ST depression in lead V5 or equivalent on early exercise testing after acute myocardial infarction predicts a high risk of death. To evaluate exercise testing and radionuclide ventriculography in this context 103 consecutive patients with myocardial infarction who were able to undertake a limited exercise test before discharge from hospital were exercised and underwent gated blood pool scanning. No serious complications resulted from exercise testing. Twenty nine patients developed ST depression in lead V5, 19 had exertional hypotension, 31 developed a heart rate of greater than or equal to 130 beats/min, and 15 had complex ventricular arrhythmias. Death during the first year after discharge from hospital was associated with exertional hypotension (p less than 0.001) and a heart rate on exercise testing of greater than or equal to 130 beats/min (p less than 0.05); these two variables identified all nine deaths. Inability to complete the exercise protocol for any reason was also predictive of death (p less than 0.01). Ventricular arrhythmias and ST depression in lead V5 induced by exercise were not significantly associated with an increased risk of death. The mean (SD) radionuclide ejection fraction in the patients who died was 29 (16%) compared with 43 (11)% in the patients who survived (p less than 0.001). ST changes on exercise testing after myocardial infarction appear to be less predictive of later complications than haemodynamic signs, which may indicate left ventricular damage rather than ischaemia.

Adult↗
PubMed1983

"Reciprocal" depression of the ST segment in acute myocardial infarction.

In acute myocardial infarction depression of the ST segment in leads distant from those showing ST elevation has been considered to be "reciprocal" but might reflect local ischaemia. To examine this possibility 103 consecutive patients who underwent exercise testing early after myocardial infarction were reviewed. Treadmill exercise testing was performed a mean of 12 (range 5-30) days after infarction using a limited Naughton protocol. Thirty five (34%) of the patients had had reciprocal change, defined as greater than or equal to 1 mm ST depression in leads remote from the site of the infarct, within 48 hours of infarction. Twenty two (63%) of the 35 patients developed exercise induced ST depression in the leads previously showing reciprocal change. Coronary artery disease was assessed in 10 of these patients by arteriography and in four at necropsy: all but one had stenosis of greater than or equal to 50% in a coronary artery supplying the reciprocal territory in addition to the disease in the vessel to the infarct site. Of patients with reciprocal ST depression, 23.5% experienced nonfatal reinfarction, pulmonary oedema after discharge, or death compared with only 9.5% of patients without reciprocal ST depression. Eight (23.5%) patients with reciprocal depression had ventricular fibrillation while in hospital compared with only two (3%) patients without. Reciprocal ST depression in acute myocardial infarction may reflect ischaemia in territory distant from the site of infarction and is associated with a high risk of fatal arrhythmias and late morbidity.

Adult↗
PubMed1983

Plasma digoxin: assay anomalies in Fab-treated patients.

Using a variety of radioimmunoassay methods, plasma digoxin concentrations were measured in two patients before and after the administration of ovine Fab antibody fragments to remove the effects of digoxin. Gross method-dependent anomalies in the results due to in vitro drug interaction were observed. More widespread use of immunotherapy may invalidate data obtained by direct immunoassay techniques.

Digoxin↗
PubMed1982

Isolated disease of left anterior descending coronary artery. Angiocardiographic and clinical study of 218 patients.

The angiocardiographic and clinical findings in 218 patients with significant obstruction confined to the left anterior descending coronary artery were reviewed to study the influence of the site of obstruction and of the collateral circulation on clinical presentation and prognosis. One hundred and fifty-six patients had been managed medically, 51 had had aortocoronary bypass operations, and 11 had had left ventricular aneurysms excised. The artery was divided into three segments: left anterior descending 1 (LAD1) from its origin to the first septal branch, left anterior descending 2 (LAD2) from the first septal to the first diagonal branch, and left anterior descending 3 (LAD3) the remaining distal vessel. Cardiogenic shock occurred only in patients with LAD1 lesions, but apart from this the clinical presentation bore no consistent relation to the site of disease. Patients with proximal lesions were more likely to have a "positive" exercise test, had more severely impaired left ventricular function, and had a worse prognosis than those with more distal disease. Non-visualisation of collateral vessels in patients with left anterior descending occlusion was associated with extensive infarction, and patients who presented with infarction had more severely impaired ventricular function than those who presented with angina and subsequently had an infarction. Left ventricular function was poor at the time of angiography in 11 of 12 of those who subsequently died; it is therefore unlikely that the prognosis of patients with isolated left anterior descending obstruction could be improved by expanding the indication for aortocoronary bypass from that of severe angina.

Adult↗
PubMed1980

The effect of prenylamine on the QT interval of the resting electrocardiogram in patients with angina pectoris.

Resting ECGs were recorded in 29 patients with angina pectoris before, during and after treatment with prenylamine 180 mg daily. The QT interval became significantly prolonged after one week of treatment. The prolongation persisted as long as therapy was continued, which was up to 6 months. After withdrawal of treatment the QT interval returned to normal within 2 weeks. In this study no serious problems were encountered by those patients in whom the QT interval was prolonged.

Adult↗
PubMed1980

Warm auto-antibody with anti-G specificity.

A case involving a warm auto-antibody with anti-G specificity is described. The patient has the most probable genotype of R1R2. At the time of admission this patient had a positive direct antiglobulin test with no detectable antibody in the serum. The use of absorption and elution techniques suggested the presence of a specific antibody with specificity confirmed using the rare cells rG. This auto-antibody did not seem to cause significant in vivo hemolysis.

Aged↗
PubMed1978

Neurotransmitter modulation, phosphodiesterase inhibitor effects, and cyclic AMP correlates of afterdischarge in peptidergic neurites.

The neuroendocrine bag cells in the abdominal ganglion of Aplysia generate a long-lasting synchronous afterdischarge upon brief stimulation of an afferent pathway. After this afterdischarge the cells become refractory to further synaptic stimulation. We find that synchrony, afterdischarge, and prolonged refractoriness are properties that can be expressed in the isolated asomatic neurites of the bag cells. We have distinguished two independent types of refractoriness. The first (type I) is seen as a failure of action potentials generated in the tips of bag cell neurites to invade cell somata. The second form of refractoriness (type II) controls the duration of afterdischarge such that stimuli after the first afterdischarge produce only very short afterdischarges or fail to elicit an afterdischarge. Type II refractoriness is sensitive to serotonin and certain of its analogues, and to dopamine and the methylxanthine phosphodiesterase inhibitors. Extracellularly applied serotonin suppresses an ongoing afterdischarge while dopamine and the phosphodiesterase inhibitors, when applied at the end of the first afterdischarge, generate a subsequent afterdischarge of long duration without further electrical stimulation. None of these compounds influenced the degree of type I refractoriness. We have shown that both serotonin and dopamine stimulate the formation of cyclic AMP in the bag cell clusters and in the pleurovisceral connectives and that the occurrence of an afterdischarge is associated with a specific increase in total cyclic AMP in bag cell bodies. Moreover, afterdischarges can be generated in unstimulated preparations by extracellular application of the cyclic AMP analogues, 8-benzylthio-cyclic AMP or 8-methylthio-cyclic AMP. Our data suggest that serotonin and/or dopamine may control bag cell activity and that activation of adenylate cyclase is linked to bag cell afterdischarge.

Action Potentials↗
PubMed1978

Some aspects of the cardiovascular pharmacology of UK 14,275 in patients with coronary artery disease.

1. A phosphodiesterase inhibitor, UK 14,275 (Pfizer) was administered intravenously to six patients with suspected coronary artery disease under-going diagnostic cardiac catheterisation to assess its inotropic activity. 2. Intracardiac haemodynamic measurements included pulmonary and systemic arterial pressure. Left ventricular end diastolic pressure and left ventricular dP/dtmax were also measured, in addition to cardiac output using the indocyanine green dye technique. 3. UK 14,275 resulted in a significant increase in LV dP/dtmax and cardiac output. 4. No chronotropic action was observed using this agent. 5. This agent may have potential therapeutic value in the management of cardiovascular failure associated with low cardiac output.

Aged↗
PubMed1978

Clinical electrophysiological effects of atenolol--a new cardioselective beta-blocking agent.

Atenolol, a cardioselective beta-blocking agent, at dose levels of 0.03, 0.06, and 0.12 mg/kg intravenously, produced prolongation of atrioventricular nodal conduction in 22 patients with suspected coronary artery disease. In a dose of 0.12 mg/kg body weight atenolol produced significant prolongation of sinus cycle length, sinus node recovery time, atrioventricular node conduction, and the effective and functional refractory periods of the atrium and the atrioventricular node. No significant effects were observed on the His Purkinje system or the effective refractory periods of the ventricle. In these actions atenolol closely resembles propranolol. However, because in contrast to propranolol it increases atrial refractoriness, it may have advantages in the treatment of atrial arrhythmias.

Atenolol↗
PubMed1976

A study of labetalol in patients of European, West Indian and West African origin.

1 Hypertension in West Indians and Africans is common and has an unacceptably high mortality in the younger patients. 2 Fifty-three patients received labetalol (a combined alpha- and beta-adrenoreceptor antagonist) as part of an open evaluation of its anti-hypertensive effect. Ten non-caucasian patients were included. 3 Significant reductions in systolic and diastolic pressures were obtained in the caucasian patients, the African and West Indian patients remaining refractory to therapy.

Adult↗
PubMedDate not supplied

A sensitive high-performance liquid chromatographic assay for the cholecystokinin-B antagonist, CI-988, in human and monkey plasma.

A sensitive and specific high-performance liquid chromatographic assay for the non-peptide cholecystokinin subtype B receptor antagonist, CI-988, in human and cynomolgus monkey plasma has been developed and validated. The method involves isolation of CI-988 and internal standard by batch robotic solid phase extraction with a C18 cartridge, liquid chromatographic separation on a C18 column and quantitation by fluorescence detection. The human plasma assay is linear from 0.25 to 500 ng/mL for a 1.00-mL plasma aliquot. Assay precision for CI-988 based on human plasma quality control samples was within +/- 7.2% relative standard deviation with an accuracy of +/- 5.6% relative error. The monkey plasma assay is linear from 1.00 to 250 ng/mL for a 0.500-mL plasma aliquot. Assay precision based on monkey plasma quality control samples was within +/- 11.0% relative standard deviation with an accuracy of +/- 2.6% relative error.

Animals↗
PubMedDate not supplied

Benchmarking for strategic action.

By focusing on three key elements--customer expectations, competitor strengths and vulnerabilities, and organizational competencies--a company's benchmarking effort can be designed to drive the strategic planning process.

Costs and Cost Analysis↗