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Biomedical subjects

S H Foster

Publications and source records attributed to S H Foster.

7 recordsLinked to original sources
PubMed1989

Antagonism of leukotriene receptors and administration of a 5-lipoxygenase inhibitor do not affect hypoxic vasoconstriction.

The role of leukotrienes in hypoxic vasoconstriction remains controversial. Our previous study using the lipoxygenase inhibitor BW 755C in dogs failed to show a substantive role for leukotrienes in hypoxic vasoconstriction. To clarify further the role of leukotrienes, we designed 3 protocols. In the first protocol, we examined the effects of LTD4 boluses on the pulmonary circulation in 6 anesthetized dogs. LTD4, 1 microgram/kg, (a large dose relative to other species) produced no detectable constriction of the pulmonary artery, while systemic vascular resistance increased 41 +/- 17% (SD), left atrial pressure rose 3.5 +/- 1.5 mmHg, and cardiac output fell 18 +/- 8%. Two leukotriene receptor antagonists, LY171883 and L-648051, decreased these effects by more than 50%. In the second protocol, we tested these antagonists in 7 anesthetized, paralyzed, closed-chest dogs with acute left lower lobe atelectasis. Two manifestations of hypoxic vasoconstriction were examined: shunt fraction (as an inverse indicator of regional constriction in response to local hypoxia) and the pulmonary pressor response to global alveolar hypoxia (as an index of general hypoxic vasoconstriction). During normoxia before administration of the inhibitor, shunt fraction, measured using an SF6 infusion, was 25 +/- 7%. The pulmonary pressor response to hypoxia, defined as the increase in pulmonary end-diastolic gradient (PDG) produced by 10% O2 inhalation, averaged +10.5 +/- 3.6 mmHg. The increase in pulmonary vascular resistance (PVR) with hypoxia was +2.4 +/- 1.7 mmHg/L/min. Then, during normoxia, 1 of the 2 antagonists was administered. Shunt fraction was unchanged (26 +/- 4%; p = 0.5). The pressor response to hypoxia was slightly less but remained substantial (the increase in PDG with hypoxia was +7.9 +/- 2.8 mmHg; p less than 0.05; the increase in PVR was +1.8 +/- 1.2 mmHg/L/min, p less than 0.10). In the third protocol we gave RG 5901, a relatively specific 5-lipoxygenase inhibitor, to 5 dogs with lobar atelectasis. The indices of hypoxic vasoconstriction were not affected by RG 5901. Shunt fraction was 29.5 +/- 8.1% before and 27.0 +/- 7.4% after RG 5901 (p greater than 0.05). The pressor response to hypoxia was +8.9 +/- 2.1 mmHg before and +8.7 +/- 3.7 mmHg after RG 5901 (p greater than 0.05). We conclude that in dogs, hypoxic vasoconstriction does not appear to be mediated by leukotrienes.

Acetophenones↗
PubMed1987

Effectiveness of language intervention with the language/learning disabled.

This paper uses a meta-analytic procedure to assess the effectiveness of language intervention with the language/learning disabled. A total of 43 studies were coded and analyzed for design, subject, and treatment characteristics. A mean effect size (ES) of 1.041 was achieved suggesting that the average language-disordered child moved from the 50th percentile to the 85th percentile as a result of language intervention. An analysis of the data for this study revealed several significant (p less than .05) ES differences for subject and treatment characteristics. The nature of the differences and their relationship to intervention are discussed.

Child↗
PubMed1983

Fibroma in a Nine-banded armadillo (Dasypus novemcinctus).

An adult male Nine-banded armadillo (Dasypus nonemcintus) had a large tumour between the first and second phalanges of the right fore-foot. The tumour was of dermal origin, consisted of dense interlacing bundles of collagen, and contained numerous fibroblasts with elongate nuclei and sparse cytoplasm. Mitotic figures were not observed, there was no evidence of lipid accumulation, and there was no metastasis to regional lymph nodes or other tissues. Electron microscopy showed that the major cells of the tumour were fibroblasts. These did not contain nuclear or cytoplasmic inclusions but had dense bodies in the nucleus and there was a conspicuous absence of lysosomes. This lesion was considered to be a benign fibroma of undetermined aetiology.

Animals↗
PubMed1978

Nonfatal methazolamide-induced aplastic anemia.

An 83-year-old man developed nonfatal aplastic anemia after taking methazolamide for three months. We made a diagnosis of methazolamide-induced aplastic anemia, discontinued all medication, gave the patient platelet and red blood cell transfusions, and treated him with oxymetholone. Approximately four months after initiation of treatment, the patient felt well, and he is currently receiving packed red blood cell transfusions every three weeks.

Acetazolamide↗
PubMed1977

Chemical analysis of an angiofibroma from a patient with tuberous sclerosis.

Amino-acid analyses on the acid hydrolysates of an angiofibroma and skin established that the former tissue contained less collagen than skin based on the reduced content of hydroxyproline, glycine, proline and alanine in the tumour. From lysosomal enzyme measurements it became evident that the specific activities of the hexosaminidases, beta-glucuronidase and beta-galactosidase were elevated. Analyses of the alcohol insoluble fraction following pronase digestion revealed that the tumour contained more acidic glycosaminoglycan (AG) than skin as assessed by uronic acid and hexosamine measurements. More outstanding, however, was the seven-fold increase in the total carbohydrate in the AG fraction of the tumour. The overall composition of this fraction was very similar to comparable material from foetal skin except that the tumour fraction contained increased sulphate concentration.

Adult↗