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Biomedical subjects

A T Gibson

Publications and source records attributed to A T Gibson.

26 records · Page 2Linked to original sources
PubMed1993

Growth retardation after dexamethasone administration: assessment by knemometry.

Knemometry has been used to measure lower leg growth during 32 nine day courses of dexamethasone in 26 babies ranging from 24 to 32 weeks' gestation at birth. Mean leg length velocity was 0.37 mm/day in the 10 days before steroids. Administration of dexamethasone was associated with a decrease in velocity in all babies, and in 15 leg shortening was documented. Mean leg length velocity during steroid treatment was -0.003 mm/day. After the course of dexamethasone was completed there was an immediate increase in leg length velocity to a mean of 0.52 mm/day over the first 10 days then falling to a value similar to the growth velocity observed before treatment. Leg length had reached the value predicted by growth before steroids about 30 days after dexamethasone. The reduction in leg length velocity occurred despite a significant increase in energy intake and decrease in oxygen requirements.

Anthropometry↗
PubMed1978

A study of the composition of pericardial fluid, with special reference to the probable mechanism of fluid formation.

The composition of pericardial fluid and simultaneously withdrawn plasma have been measured in rabbits and greyhounds. 1. Sodium and chloride distributions were found to be not markedly different from the ratio predicted for a passive distribution. The small deviation found in greyhounds could be largely corrected by the in vitro dialysis of plasma against pericardial fluid. 2. Calcium and magnesium were distributed in a manner expected from a passive ultrafiltrate of plasma. 3. Pericardial fluid was found to contain between one quarter and one third of the protein of plasma. 4. Separation of the protein constituents demonstrated a far higher proportion of albumin to other proteins in the pericardial fluid. 5. The osmolality of plasma was slightly higher than that of pericardial fluid, as would be expected from a plasma ultrafiltrate. 6. The potassium concentration of pericardial fluid was higher than the plasma concentration in all animals studied. This difference could be abolished, and an expected distribution obtained in the samples from greyhounds, by the in vitro dialysis of plasma against pericardial fluid. This observation for potassium cannot be attributed to haemolysis of blood in pericardial fluid samples or to the use of any inappropriate references. It is suggested that the elevated potassium concentration of pericardial fluid may reflect the lability of the cardiac intracellular potassium during cardiac contraction. 7. The results obtained in this study do not support the concept of an active secretion of pericardial fluid as has been claimed by others. The distribution of ions would appear to be passive and to follow the values predicted by the Gibbs-Donnan relationship.

Animals↗
PubMed1978

A study of the routes by which protein passes from the pericardial cavity to the blood in rabbits.

The routes by which radioiodinated serum albumin placed in the pericardial cavity gains access to the circulation have been investigated in rabbits. 1. Eighty per cent of pericardial cavity protein passes through the parietal pericardium and into the circulation through the thoracic duct. 2. A small amount of protein is drained through the right lymph duct; this is probably derived from protein passing from the pericardial cavity into the pleural cavity. 3. There is no apparent movement of protein directly into blood vessels of the parietal pericardium. For theoretical reasons movement of protein across the visceral pericardium and into the blood vessels of the myocardium is also unlikely. 4. A small amount of protein enters the circulation when both major lymphatics are ligated. It is proposed that lymphatic uptake may continue and secondary lymphovenous junctions will open as a result of raised intralymphatic pressure.

Animals↗
PubMedDate not supplied

Unusual case of tracheal agenesis.

We describe the clinical presentation and pathological features of an unusual case of tracheal agenesis. The axial derivatives of the primitive foregut between the larynx and stomach were represented by a single structure featuring sequential segmentation into regions showing exclusively tracheal or esophageal differentiation in a pattern that is not easily classified by existing nosologic systems nor explained by the conventional hypothesis of dysontogenesis.

Abnormalities, Multiple↗
PubMedDate not supplied

Surfactant and the neonatal lung.

Deficiency of pulmonary surfactant is responsible for a substantial proportion of the mortality and morbidity in infants born prematurely. Surfactant replacement therapy has been extensively investigated and has become a central part of neonatal intensive care in the UK over the last 3 years. Evidence for the efficacy of this treatment is provided as is a discussion of the different surfactant preparations available and different protocols for administration.

Clinical Protocols↗