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Biomedical subjects

J S Scott

Publications and source records attributed to J S Scott.

At least 127 records · Page 7Linked to original sources
PubMed1988

Beta-adrenergic blockade in ponies with recurrent obstructive pulmonary disease.

Ponies with recurrent airway obstruction have hyperresponsive airways during acute disease exacerbations but not during clinical remission. We examined the effect of beta-adrenergic blockade with propranolol on airway responsiveness to aerosol histamine in six ponies with recurrent airway obstruction and six age- and gender-matched controls. Measurements were made with principal ponies in clinical remission (period A) and during an acute period of airway obstruction (period B). beta-Adrenergic blockade did not change airway responsiveness, dynamic compliance (Cdyn), or pulmonary resistance (RL) in either group of ponies at period A or in the control ponies at period B. In principal ponies at period B, propranolol significantly increased RL but was without effect on Cdyn or airway responsiveness. We conclude that the beta-adrenergic system is involved in the control of central airway caliber in principal ponies at period B but that this system does not seem to be involved in the mechanism of airway hyperresponsiveness to histamine.

Airway Resistance↗
PubMed1988

Alpha 1-adrenergic-induced airway obstruction in ponies with recurrent pulmonary disease.

We examined the response of five ponies with recurrent airway obstruction (principals) and five age- and gender-matched controls to the aerosol alpha-adrenergic agonist phenylephrine after blockade with propranolol and atropine. Measurements were made with principal ponies in clinical remission (period A) and during acute airway obstruction (period B). The blockade had no effect on base-line pulmonary mechanics in control ponies during periods A and B or in the principal ponies during period A. However, in the principal ponies during period B, blockade increased dynamic compliance (Cdyn) and decreased pulmonary resistance (RL). Phenylephrine had no effect on the controls during either period. In the principals, phenylephrine decreased Cdyn and increased RL during both periods. The alpha 1-agonist aerosol prazosin shifted the phenylephrine dose-response curves to the right, but prasozin did not bronchodilate the principals during period B. This suggests that the role of alpha 1-adrenergic receptors in airway narrowing in ponies with recurrent airway obstruction is minimal. However, the response to phenylephrine in only the principal ponies suggests an increase in alpha-receptor numbers and/or activity in these animals compared with controls.

Airway Obstruction↗
PubMed1988

Effects of atropine in ponies with recurrent airway obstruction.

The effects of atropine on lung function and airway reactivity in two groups of ponies were measured. Principal ponies had a history of recurrent airway obstruction when housed in a barn and fed hay; control ponies had no history of airway obstruction. Principal and control ponies were paired, and measurements were made when principal ponies were in clinical remission (period A) and during an acute attack of airway obstruction (period B). Atropine did not alter pulmonary resistance (RL), dynamic compliance (Cdyn), or airway responsiveness in either group of ponies at period A or in the controls at period B. In principal ponies at period B, atropine did not alter Cdyn or the concentration of aerosol histamine required to decrease Cdyn to 65% of base line (ED65Cdyn) but reduced RL and the change in RL induced by 0.1 mg/ml histamine (delta RL0.1). It is likely that the latter observation was due to geometric changes in the airways, because the change in RL and in delta RL0.1 were significantly correlated. The results of this study show little resting bronchomotor tone in normal ponies, but a major portion of the increase in RL in principals at period B is mediated via muscarinic receptors. Little evidence exists for muscarinic receptor involvement in the response to aerosol histamine in either principal or control ponies.

Aerosols↗
PubMed1988

Evidence for secondary 5 alpha-reductase deficiency in genital and supra-pubic skin of subjects with androgen insensitivity syndrome.

The activity of 5 alpha-reductase in genital and supra-pubic skin (homogenate or fibroblasts) from subjects with complete or incomplete androgen insensitivity syndrome was low compared with mean activity in samples from normally differentiated male controls. Also, in two subjects with incomplete androgen insensitivity syndrome the ratio of the concentration of testosterone to that of 5 alpha-dihydrotestosterone in plasma was raised after hCG stimulation but normal under basal conditions. In three subjects with complete androgen insensitivity syndrome there was no evidence of raised ratios of testosterone to 5 alpha-dihydrotestosterone in plasma under basal or hCG-stimulated conditions. The activities of other steroid metabolizing enzymes, e.g. 17 beta-hydroxysteroid dehydrogenase, 3 alpha/beta-hydroxysteroid dehydrogenase, were not decreased. The low 5 alpha-reductase activity of androgen insensitive subjects reported here, and by others, may imply that this enzyme in genital skin is in some way androgen dependent, or responsive to other factors associated with androgen insensitivity syndrome.

17-Hydroxysteroid Dehydrogenases↗
PubMed1988

Prospective payment for physician services: a "RAP" (radiology, anesthesiology, pathology) on the future.

Development of a prospective payment system for physician services under Medicare and Medicaid is still being considered in Washington. The first step will be to "bundle" radiology, anesthesiology and pathology ("RAP") services into existing Medicare DRG schedules. Other hospital-based physician services, including surgery and medical management, may also be included.

Anesthesiology↗
PubMed1988

Aerosolized Micropolyspora faeni antigen as a cause of pulmonary dysfunction in ponies with recurrent airway obstruction (heaves).

Ponies with recurrent airway obstruction (principal ponies) and their controls were given aerosolized Micropolyspora faeni antigen via endotracheal tube during a period when the principal ponies were in disease remission. In both groups of ponies, we performed bronchoalveolar lavage (BAL) and measured pulmonary function at base line, and 5 hours after aerosol administration of 30 ml of 0.9% NaCl solution or 30 ml of 1% w/v particulate M faeni antigen in 0.9% NaCl solution. In both groups of ponies, aerosolized M faeni antigen increased WBC count, neutrophil numbers, and albumin concentration in BAL fluid, but macrophage numbers decreased. In the principal ponies, BAL mast cell numbers were decreased 5 hours after administration of M faeni antigen. The M faeni antigen had no effect on the mechanical properties of the lungs or on gas exchange in the control ponies, but did increase respiratory frequency minute ventilation and pulmonary resistance, and decreased arterial oxygen tension in the principal ponies. Changes in pulmonary function were apparent only in the principal ponies, which suggests that neutrophils, per se, do not cause pulmonary dysfunction and that M faeni may be one of the etiologic agents involved in chronic obstructive pulmonary disease.

Aerosols↗
PubMed1987

False positive results of tests for syphilis and outcome of pregnancy: a retrospective case-control study.

In a retrospective case-control study 64 women yielding a false positive result to a test for syphilis in pregnancy were compared with 128 controls individually matched for age, parity, hospital of delivery, and year of delivery. There were significantly more unsuccessful pregnancies, mainly spontaneous abortions during the first and second trimesters, among women with persistent false positive results. There was no significant difference between groups in the mean birth weights of liveborn infants. The antibodies responsible for the false positive result may indicate the presence of an immunological disturbance. Women who give a false positive result should be carefully managed throughout their pregnancy.

Abortion, Spontaneous↗
PubMed1987

Incomplete masculinization due to a deficiency of 17 beta-hydroxysteroid dehydrogenase: comparison of prepubertal and peripubertal siblings.

Incomplete masculinization due to a deficiency of 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) was investigated in siblings aged 4 years (Case 1) and 12 years (Case 2). Diagnosis was based on increased ratios of androstenedione (A) to testosterone (T) in blood, and impaired reduction of A to T by 17 beta-HSD in vitro in the testes. Impairment was total in Case 2 but partial in Case 1. Case 2 also showed deficient conversion of dehydroepiandrosterone (DHA) to androstenediol and of oestrone to oestradiol by 17 beta-HSD which were normal in Case 1. Oxidation of T to A by 17 beta-HSD and conversion of 17 alpha-hydroxyprogesterone to A by 17,20 desmolase were normal in the testes of both siblings. 3 beta-HSD conversion of DHA to A was normal in Case 1, but markedly increased in Case 2. In contrast to testicular findings, 17 beta-HSD reduction of A to T in genital skin fibroblasts from Case 2 was normal and diagnosis would not have been possible from studies of measurements of this enzyme in skin. The severity of the testicular 17 beta-HSD deficiency in the peripubertal compared with the prepubertal sibling suggests either considerable intra-familial variation in the extent of the enzyme defect or that puberty may aggravate this disorder. The normal reductive action of 17 beta-HSD in skin, despite impaired action in testes, suggests involvement of more than one iso-enzyme.

17-Hydroxysteroid Dehydrogenases↗
PubMed1987

Micropolyspora faeni causes airway inflammation but not hyperresponsiveness in sensitized ponies.

We assessed the effect of aerosol Micropolyspora faeni challenge in two groups of ponies by measuring lung function, airway reactivity to aerosol histamine, and bronchoalveolar lavage fluid cytology. One group of ponies was sensitized by subcutaneous injection of M. faeni in complete Freund's adjuvant, and the other group served as control. In both groups of ponies, measurements were made at base line and 5 h after aerosol administration of 30 ml of saline or 30 ml of 1% wt/vol particulate M. faeni antigen in saline. Saline challenge had no effect on any of the measured variables. M. faeni challenge had no effect on pulmonary mechanics or gas exchange in the control group but significantly increased respiratory frequency and minute ventilation and decreased arterial CO2 tension in the sensitized ponies. In both groups of ponies, aerosol M. faeni challenge significantly increased total white blood cell count and neutrophil numbers in bronchoalveolar lavage fluid while large mononuclear cell numbers decreased. Airway responsiveness was unaltered by saline or M. faeni challenge in both pony groups. We conclude that aerosol M. faeni challenge induces pulmonary neutrophilia and abnormalities of ventilation but is not accompanied by airway hyperresponsiveness in sensitized ponies.

Aerosols↗
PubMed1987

The effect of cysteamine, cystamine, and the structurally related compounds taurine, N-acetyl-cysteine, and D-penicillamine on plasma prolactin levels in normal and estrogen-primed hyperprolactinemic rats.

Studies were undertaken to evaluate the effects of cysteamine (CSH), cystamine (CS-S), N-acetyl-cysteine, D-penicillamine, and a major metabolite of CSh, taurine, on plasma PRL levels in normal and estrogen-primed hyperprolactinemic rats. Both CSH and CS-S caused a marked decrease in plasma PRL concentration in hyperprolactinemic rats. The effects of CSH and CS-S lasted for at least 6 h but returned toward pretreatment levels 24 h later. In normal rats a fall in basal plasma PRL concentration was not readily observed but after stimulation with TRH or metaclopramide, PRL secretion elicited by these stimuli was markedly inhibited by CSH and CS-S. The response to TRH or MCP 24 h after treatment with CSH was variable with CS-S appearing to cause an unexpected increase in PRL release in response to TRH or metaclopramide. The structurally related compounds, taurine, N-acetyl-cysteine, and D-penicillamine did not cause any reduction of plasma PRL levels in hyperprolactinemic rats. This may be due, in the case of taurine, to a loss of the free sulfydryl group, in the case of N-acetyl-cysteine, a change in basicity because of a carboxyl group and derivatization of the amino group and D-penicillamine, again a change in basicity due to a free carboxyl group as well as an altered structural relationship between the free amino and sulfydryl groups. These studies indicate that CSH and CS-S by possible reduction to CSH cause a reversible depletion in plasma PRL in normal and hyperprolactinemic rats. Because both substances inhibit different receptor-mediated stimuli, their mechanism of action is likely to be mediated at a common locus involved with the synthesis and release of PRL.

Acetylcysteine↗
PubMed1987

Effect of clenbuterol on histamine-induced airway obstruction in ponies.

We determined the effect of IV administered beta 2-adrenergic receptor agonist clenbuterol on pulmonary function and on the response to histamine in 12 healthy ponies. Measurements were made at base line and after saline solution or clenbuterol was administered IV at a dosage of 0.2, 0.8, or 1.6 micrograms/kg. The dosage of clenbuterol used in each study was unknown to the investigators until all the data had been analyzed. Intravenous administration of saline solution or clenbuterol did not alter base-line pulmonary function significantly. Aerosol histamine administration significantly decreased arterial oxygen tension and dynamic compliance and increased pulmonary resistance, respiratory frequency, and minute ventilation, but had no effect on arterial carbon dioxide tension and tidal volume. The magnitude of change in these variables was unaffected by previous administration of clenbuterol at any of the dosages tested. We conclude that clenbuterol at the dosages tested is not a bronchodilator in healthy ponies and does not exert a significant protective effect against aerosol histamine-induced airway narrowing.

Airway Obstruction↗
PubMed1986

Maternal antibodies against fetal cardiac antigens in congenital complete heart block.

An immunologic basis for congenital heart block has been proposed previously. To investigate the association between congenital heart block and maternal antibodies capable of crossing the placenta, we used immunofluorescence to examine serum samples from 41 mothers and 8 affected children, together with serum from controls, for antibodies to fetal cardiac tissue. Twenty-one mothers (51 percent) had IgG antibody reactive with fetal heart tissue, as compared with only 9 of 94 controls (10 percent; P less than 0.001). Three of 8 affected babies, but none of 50 healthy babies, had similar antibodies. The antibodies reacted with all myocardial tissue and were not directed specifically to the conduction system. They also reacted with other fetal tissues and could be distinguished from nuclear and smooth-muscle autoantibodies. We also observed a higher occurrence of antibodies to cytomegalovirus, but not to Epstein-Barr virus, in these mothers. Autopsy specimens from babies with congenital heart block examined by immunoperoxidase staining showed deposition of immunoglobulin and complement components in all cardiac tissues. These findings strengthen the case implicating immune reactivity related to maternal antibody in the development of some but not all cases of congenital heart block.

Antibodies, Antinuclear↗