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Biomedical subjects

P Little

Publications and source records attributed to P Little.

103 records · Page 6Linked to original sources
PubMed1988

Gallstones at autopsy and cholecystectomy: a comparative study.

An examination of 613 post-mortems gave a prevalence of biliary disease at autopsy of 36.5%, higher than reported previously in Australia. This consisted of an asymptomatic gallstone prevalence of 18.9%, with a further 5.7% of the autopsies having granular biliary sludge and 11.9% having had a previous cholecystectomy. Although the rate of occurrence of cholesterol gallstones was approximately half that of the pigment gallstones and pigment biliary sludge combined, no significant association between the sex of the postmortems and stone type was observed at autopsy (chi 2(1) = 0.1: P greater than 0.05). The ratio of biliary disease between females and males was approximately 2:1. Gallstones and biliary sludge from 310 cholecystectomy patients showed that cholesterol gallstones were approximately twice as common in men, and approximately six times as common in women than pigment gallstones. In this group of patients there was a significant association between the sex of the patient and the rate of occurrence of stone type. The rate of occurrence of cholesterol gallstones was significantly higher than pigment gallstones in both the males and females at cholecystectomy (chi 1(2) = 18.97; P less than 0.0001). A female to male ratio of approximately 2:1 was also observed. A statistically significant higher rate of pigmented biliary disease was observed at autopsy than at cholecystectomy. (chi 2 = 101.0; P less than 0.0001). Analyses on biliary sludge, a filterable, fine granular pigmented material in bile, suggest that it may be the direct precursor for a number of different gallstone types.

Adult↗
PubMed1988

Cerebral depression due to propylene glycol in a patient with chronic epilepsy--the value of the plasma osmolal gap in diagnosis.

A case of propylene glycol poisoning is described in a 39 year old woman which resulted in her admission to hospital in status epilepticus. She had had a long-standing history of uncontrollable epilepsy. The diagnosis of propylene glycol poisoning resulted directly from the finding of a high plasma osmolal gap on admission. This finding would have been missed if later samples only had been analysed. Plasma osmolality and the osmolal gap should be considered first line investigations in patients presenting with metabolic acidosis and cerebral signs and symptoms. Since her discharge from hospital a year ago the patient has had no further seizures.

Acidosis↗
PubMed1988

Serum from partially hepatectomized rats induces primary hepatocytes to enter S phase: a role for prostaglandins?

Serum obtained from partially hepatectomized rats 1, 3 or 24 h after operation was more effective in stimulating DNA synthesis in primary adult rat hepatocytes than serum from sham-operated rats; exposure to the serum for 2 h was sufficient to promote growth. Serum from the partially hepatectomized rats contained elevated levels of PGE2 and PGF2 alpha; it promoted hepatocytes to release prostaglandins into their culture medium. Growth-promoting effects of the serum and its capacity to elicit prostaglandin release into the culture medium were inhibited by 0.1 mM-indomethacin or 1 mM-aspirin. 0.1 mM-indomethacin also prevented DNA synthesis if the inhibitor were added 4 h after growth had been initiated by serum from partially hepatectomized rats, suggesting that prostaglandins continue to be important for the maintenance of hepatocyte growth for at least 6 h.

Animals↗
PubMed1986

The relationship between coronary pressure during reperfusion and myocardial recovery after hypothermic cardioplegia.

The aim of this study was to document the relationship between coronary pressure during reperfusion and myocardial recovery after hypothermic cardioplegia. Isolated canine hearts perfused by a support dog were subjected to 2 hours of cardioplegia at 20 degrees C. Three hearts were reperfused at each of the following pressures: 20, 40, 60, 80, 100, and 150 mm Hg. The reperfusion period lasted 30 minutes, with the pressure being raised gradually from zero to the test level over the first 2 minutes, then being held constant until the end of the period. The results showed that the normal dog heart after 2 hours of hypothermic cardioplegia is tolerant to a wide range of coronary pressures during reperfusion. Hearts reperfused at pressures between 40 and 100 mm Hg had similar values for coronary blood flow, coronary sinus oxygen saturation, myocardial oxygen consumption, lactate flux, contractility, and myocardial adenosine triphosphate content. If coronary reperfusion pressure was 20 mm Hg, [corrected] myocardial rewarming was delayed, myocardial oxygen consumption was decreased, and myocardial ischemia was manifested by marked lactate efflux, high myocardial lactate concentration, and depletion of adenosine triphosphate. If pressure was 150 mm Hg, coronary flow was excessive. To place these results in the context of coronary artery disease, we measured reperfusion pressure in coronary arteries distal to a stenosis in 10 patients studied at the time of coronary bypass grafting. In 13 arteries with major stenoses, distal mean coronary pressure averaged 31 mm Hg while the simultaneously measured mean aortic or radial artery pressure averaged 66 mm Hg. Thus the average gradient across the stenoses was 35 mm Hg (range 15 to 60 mm Hg). We concluded that in normal hearts without ischemic damage, reperfusion can be conducted satisfactorily at mean coronary pressures from 40 to 100 mm Hg. In setting the tolerable limits for reperfusion pressure in patients with severe coronary artery disease, one should make allowance for pressure gradients of up to 60 mm Hg between the aorta and the distal coronary artery.

Adenosine Triphosphate↗
PubMed1984

Plasma noradrenaline kinetics in humans.

Recently developed radiotracer methods for measuring the overall rate of release of noradrenaline to plasma, for the body as a whole, can be used to estimate 'total sympathetic nervous system activity' in humans. These techniques find application in clinical studies of sympathetic nervous physiology and pharmacology. The inherent weakness of any biochemical test of global sympathetic tone such as this lies in the fact that sympathetic nervous system responses typically show regional differentiation. Biochemical indices of overall sympathetic activity are insufficiently discriminating to delineate patterns of sympathetic nervous response, representing instead an algebraic sum of all regional increases or decreases in sympathetic tone. Modification of the whole-body radiotracer methodology enables organ-specific sympathetic nervous system activity to be estimated, from measurements of regional release of noradrenaline to plasma. This should facilitate investigation of possible sympathetic pathophysiology in disease states. Illustrative of potential application of the method are preliminary findings of increased renal sympathetic nervous tone in young patients with essential hypertension, and of selective activation of sympathetic nerves to the kidney by diuretics.

Humans↗
PubMed1984

Two patients with abnormalities of regional sympathetic nervous tone.

The traditional biochemical tests of sympathetic nervous system function used in clinical diagnosis (urine and plasma catecholamine measurements) are indices of "overall" sympathetic nervous activity, and incapable of detecting localised changes in sympathetic tone confined to individual organs. Recently developed radiotracer methods, which enable the pattern of sympathetic nervous dysfunction in disease states to be delineated, were used to detect abnormalities in regional sympathetic nervous system activity in two patients presenting problems in management. In one, the abnormality of sympathetic function was iatrogenic, a post-sympathectomy denervation of the lower regions of the body, associated with incapacitating postural hypotension. In the other, unexplained persistent sinus tachycardia proved to be due to an increase in sympathetic nervous tone restricted to the innervation of the heart. Knowledge of the underlying sympathetic nervous pathophysiology in these patients influenced the choice of drugs subsequently used in their treatment.

Dihydroergotamine↗
PubMed1981

Uptake of lead by vegetable foodstuffs during cooking.

Uptake of Pb by foodstuffs during cooking has been identified as an additional potential source of human exposure to Pb. Vegetables and rice cooked in water containing Pb may adsorb up to 80% of the Pb in the water. The amount of Pb adsorbed was dependent upon the concentration of Pb in the water, type of vegetable, water hardness, salting of the water, duration of cooking and the available surface-area of the vegetables. Substantial deposition of Pb also occurred on the surfaces of the saucepan itself (Al greater than enamel greater than Teflon), with subsequent desorption under certain cooking conditions. During tea-making, the concentration of Pb in water was reduced by 30-40% due to adsorption of Pb by the tea-bags. The dietary significance of the adsorption of Pb by foodstuffs during cooking as an additional source of human Pb uptake is assessed.

Adsorption↗
PubMed1980

The structure of the human gamma-globin gene locus and its relation to the delta/beta-globin gene locus.

Previous maps of the human gamma-globin gene locus and the human delta/beta-globin gene locus have been linked to one another by the identification of a DNA fragment, generated by BamHI, that contains portions of the A gamma- and delta-globin genes. The intergene distances are: between G gamma and A gamma, 3500 base pairs; between A gamma and delta, 13,500 base pairs; between delta and beta, 5500 base pairs. All genes contained introns between the EcoRI and BamHI intragenic sites. All genes were transcribed from the same strand.

Base Sequence↗