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Biomedical subjects

P Harris

Publications and source records attributed to P Harris.

At least 181 records · Page 10Linked to original sources
PubMed1989

Pre- and post-treatment distribution pattern of 123I-MIBG in patients with phaeochromocytomas and paragangliomas.

123I-metaiodobenzylguanidine (MIBG) localizes in adrenergic neurones. A comparison of % washout of MIBG, during two time intervals, from various organs was carried out in seven normal volunteers and 11 patients with phaeochromocytoma and/or paraganglioma pre- and post-treatment using MIBG. % washout of MIBG during the time intervals of 30 min to 4 h were as follows: heart, controls 26.1 +/- 3.8 v. patients 51.5 +/- 9.1, (p less than 0.001), lungs, controls 36.5 +/- 5.3 v. patients 47.3 +/- 5.8, (p less than 0.05), liver, controls 26.5 +/- 5.7 v. patients 53.4 +/- 12.0 (p less than 0.01). Following treatment the % washout of MIBG from these tissues between 30 min and 4 h were similar in both groups of subjects. This observation coincided with the normalization of plasma catecholamine levels in most of the treatment group. There was no significant difference between the treatment and control groups, in the % washout of MIBG from these tissues during the 4 h and 22 h time intervals either before or after treatment. We conclude that quantitative scintigraphy 30 min to 4 h after MIBG administration is a useful technique to evaluate the pathophysiological effects of high circulating catecholamines in patients with phaeochromocytomas and/or paragangliomas.

3-Iodobenzylguanidine↗
PubMed1989

Are pulmonary haemodynamics of importance to survival in chronic obstructive lung disease?

Although the magnitude of pulmonary arterial pressure has been shown to be related to mortality from chronic obstructive lung disease, it does not necessarily follow that pulmonary hypertension is an important cause of death. In the majority of patients with chronic obstructive lung disease the degree of pulmonary hypertension is trivial and the cardiac output is unimpaired. The development of oedema in such cases is probably mediated through renal, neural and humoral mechanisms which may be more directly linked to the effects of CO2 retention than to disturbed pulmonary haemodynamics.

Hemodynamics↗
PubMed1989

Pulmonary endocrine cells in pulmonary arterial disease.

Pulmonary endocrine cells containing bombesin or calcitonin have been identified in human lungs by the peroxidase-antiperoxidase method. The numbers of such cells were greatly increased in patients with plexogenic pulmonary arteriopathy whether that condition was associated with primary pulmonary hypertension or with pulmonary hypertension from intracardiac shunts. The numbers of endocrine cells tended to be increased, but to a lesser extent in patients with pulmonary hypertension and medial hypertrophy of the muscular pulmonary arteries in the absence of plexogenic arteriopathy. Increased numbers of endocrine cells comprised both greater numbers of solitary cells and a pronounced clustering, often of a disorganized nature.

Adolescent↗
PubMed1988

Role of arterial pressure in the oedema of heart disease.

The primary function of the heart is maintenance of the arterial pressure that is essential for perfusion of the tissues. Cardiac output is mainly regulated by control systems acting through the arterial pressure, whereby the heart matches its output to the perfusion of the tissues, in which blood is distributed according to local vascular resistances. When the heart is disabled, the body intensifies to an abnormal degree the renal, nervous, and endocrine mechanisms through which arterial pressure is maintained. As a result, the kidneys retain excess salt and water; the volume of extracellular liquid, including the plasma, expands; and the systems that limit the blood volume are overridden.

Blood Pressure↗
PubMed1988

Subacute infantile mountain sickness.

A description is given of a disease of infants occurring in Lhasa, Tibet at an altitude of 3600 m. Typically if affects infants who have been born at low altitude and subsequently brought to residue in Lhasa, and it is usually fatal within a few weeks or months. There is extreme medial hypertrophy of muscular pulmonary arteries and muscularization of pulmonary arterioles, together with dilatation of the pulmonary trunk and massive hypertrophy and dilatation of the right ventricle. The disease is distinct from acute or chronic mountain sickness and appears to be the human counterpart of 'brisket disease' in cattle.

Altitude Sickness↗
PubMed1988

Plexiform lesion in bronchopulmonary anastomosis.

A cellular lesion developed in the bronchial component of a bronchopulmonary anastomosis in a girl of 6 years with primary pulmonary hypertension. Its histological features were consistent with those of a plexiform lesion.

Arterio-Arterial Fistula↗
PubMed1988

Pulmonary endocrine cells in various species in the Himalaya.

The numbers, morphology and distribution of pulmonary endocrine cells in goats, sheep and the yak and its interbreeds with cattle, dzos and stols, were studied after their demonstration by means of the peroxidase-antiperoxidase technique with a polyclonal antiserum raised in the rabbit to human neuron-specific enolase, a marker for neuroendocrine cells. The numbers, morphology and distribution were related to species and not to residence at high altitude. Pulmonary endocrine cells were common and mainly distributed as solitary cells in the epithelium of the bronchial tree in sheep. They were much less common and found mainly as clusters in the alveolar capillary walls in goats and in the yak and its interbreeds with cattle.

Altitude↗
PubMed1988

Molecular cloning of the alpha subunit of human and guinea pig leukocyte adhesion glycoprotein Mo1: chromosomal localization and homology to the alpha subunits of integrins.

The cell-surface glycoprotein Mo1 is a member of the family of leukocyte cell adhesion molecules (Leu-CAMs) that includes lymphocyte function-associated antigen 1 (LFA-1) and p150,95. Each Leu-CAM is a heterodimer with a distinct alpha subunit noncovalently associated with a common beta subunit. Leu-CAMs play crucial roles in cell-cell and cell-matrix interactions. We describe the isolation and analysis of two partial cDNA clones encoding the alpha subunit of the Leu-CAM Mo1 in humans and guinea pigs. A monoclonal antibody directed against an epitope in the carboxyl-terminal portion of the guinea pig alpha chain was used for immunoscreening a lambda gt11 expression library. The sequence of a 378-base-pair insert from one immunoreactive clone revealed a single continuous open reading frame encoding 126 amino acids including a 26-amino acid tryptic peptide isolated from the purified guinea pig alpha subunit. A cDNA clone of identical size was isolated from a human monocyte/lymphocyte cDNA library by using the guinea pig clone as a probe. The human clone also encoded a 126-amino acid peptide including the sequence of an additional tryptic peptide present in purified human Mo1 alpha chain. RNA gel blots revealed that mature Mo1 alpha chain mRNA is approximately 5 kilobases in guinea pigs and humans. Southern analysis of DNA from hamster-human hybrids localized the human Mo1 alpha chain to chromosome 16, which has been shown to contain the gene for the alpha chain of lymphocyte function-associated antigen 1. A comparison of the Mo1 alpha chain coding region revealed significant homologies with carboxyl-terminal portions of the alpha subunits of fibronectin, vitronectin, and platelet IIb/IIIa receptors. These data suggest that the alpha subunits of Leu-CAMs evolved by gene duplication from a common ancestral gene and strengthen the hypothesis that the alpha subunits of these heterodimeric cell adhesion molecules on myeloid and lymphoid cells, platelets, and fibroblasts are evolutionary related.

Amino Acid Sequence↗
PubMed1988

Haemodynamic and regional blood flow changes after acute pulmonary microembolism in conscious rabbits.

The central and peripheral haemodynamic effects of pulmonary embolisation with microspheres were measured in conscious rabbits in which the autonomic and central nervous systems were functioning normally. Sufficient microspheres were given to reduce cardiac output (measured by thermodilution) by one half. This fall in cardiac output was accompanied by a severe fall in arterial pressure and an increase in heart rate and right atrial pressure. Under these conditions cardiac output responded less than normally to an increased right atrial pressure imposed by an infusion of saline. Changes in regional blood flow and resistance were measured with radioactive microspheres injected into the left ventricle. Myocardial blood flow was unaffected by pulmonary embolisation. Cerebral flow was slightly increased. Renal, intestinal, dermal, and skeletal muscle blood flows were all reduced. Myocardial and cerebral tissue vascular resistances decreased; splenic and dermal vascular resistances increased; and renal and skeletal muscle vascular resistances were unchanged.

Animals↗
PubMed1988

The value of two-dimensional echocardiography and pulsed Doppler technique in facilitating percutaneous catheterization of the subclavian vein.

We have found combined two-dimensional echocardiographic imaging and range-gated pulsed Doppler flow mapping to be very useful and accurate in identifying the location and course of the subclavian vein. It can be efficiently utilized to minimize the incidence of iatrogenic complications during percutaneous central venous catheterization. This is particularly relevant in patients who are predisposed to a high risk of complications from the procedure.

Catheterization, Central Venous↗
PubMed1988

The effects of high intensity exercise on the plasma concentration of lactate, potassium and other electrolytes.

To study the effect of short term high intensity exercise on plasma lactate, potassium, sodium and chloride concentrations, five Thoroughbred horses were galloped on a treadmill at a 5 degree incline. Following a standardised warm-up period, they were galloped at 8, 10, or 12 metres/sec for 2 mins. One horse also galloped at 14 metres/sec for 1.5 mins. Sequential arterial and/or venous blood samples were collected during exercise and recovery. At 12 metres/sec, the effect of different recovery modes, ie, standing, walking or trotting, on the electrolytes was also examined. There was a progressive rise in plasma potassium concentration during galloping, with peak values occurring at the end of the exercise bout. In some cases, values above 10 mmol/litre were recorded at the highest workloads. Plasma lactate concentrations peaked during early recovery, with values up to 32 mmol/litre. A high correlation existed between peak potassium and lactate concentrations (venous r = 0.923, and arterial r = 0.989). Following exercise there was a rapid return to baseline plasma potassium concentrations, but by 12 mins recovery there was still an elevated lactate concentration, the extent depending on the intensity of the exercise bout and the recovery mode. There was a small rise in plasma sodium but no significant change in plasma chloride concentrations during exercise. However, when adjusted for the decrease in plasma volume, as determined from total plasma protein concentration, there was a decrease in circulating amounts of both electrolytes.

Animals↗
PubMed1988

Atypical myoglobinuria: an acute myopathy in grazing horses.

Four out of 12 horses grazing a field in Berkshire, England, suffered a prostrating illness and died within 12 to 72 h. Serum biochemical abnormalities, including markedly elevated muscle enzymes, were demonstrated and at post mortem widespread myodegeneration was found in both skeletal muscle and myocardium. Urine analysis revealed myoglobinuria, and renal changes were seen histologically. Although similar pathologically, the clinical syndrome and circumstances of the outbreak were not typical of equine exertional rhabdomyolysis (EER). The outbreak bore a striking resemblance to other reported sporadic outbreaks of an atypical myoglobinuria occurring in grazing horses. A number of potential aetiological and contributory factors (including herbicide toxicity) were considered, but the aetiology remains unresolved.

Animals↗