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Biomedical subjects

S Epstein

Publications and source records attributed to S Epstein.

At least 271 records · Page 15Linked to original sources
PubMed1976

Effect of oxygen in graded concentrations upon tracheal mucous velocity. A study in anesthetized dogs.

Graded concentrations of oxygen were used to establish dose-duration relations for the effect of oxygen on tracheal mucous velocity and tracheobronchial histologic findings in the anesthetized dog. Observations of tracheal mucous velocity were made during 30-hour periods of breathing air (100-percent humidified and warmed to 38 degrees C) and oxygen mixtures (also 100-percent humidified and warmed to 38 degrees C). In animals breathing oxygen mixtures, the baseline tracheal mucous velocity was taken as the value while breathing room air at the experiment's start. No statistically significant differences in tracheal mucous velocity occurred during air breathing. Tracheal mucous velocity fell 45 percent from the baseline value after breathing 100-percent oxygen for two hours (P less than 0.01), fell 42 percent after 75-percent oxygen for nine hours (P less than 0.01) and fell 51 percent after 50-percent oxygen for 30 hours (P less than 0.001). Histologic examination of the trachea and major bronchi after six hours of 100-percent oxygen and 12 hours of 75-percent oxygen revealed signs of acute tracheobronchitis. Minor histologic alterations in the tracheobronchial tree occurred both in animals breathing air and 50-percent oxygen for 30 hours; therefore, histologic evidence of oxygen toxicity could not be established at 30 hours. These findings indicate that in the anesthetized dog, oxygen depresses mucous transport as a function of inspired oxygen concentration (FIO2) and that even FIO2 as low as 0.05 might be deleterious.

Acute Disease↗
PubMed1976

Effect of beta-adrenergic agonists aerosolized by freon propellant on tracheal mucous velocity and cardiac output.

The present study was designed to assess the effects of two beta-adrenergic agonists, isoproterenol sulfate and carbuterol hydrochloride, and aerosolized Freon propellant (a mixture of Freon II, Freon 12, and Freon 114) on tracheal mucous velocity and cardiac output in anesthetized dogs. Five groups of ten animals each received the following dosages of aerosols: Freon, 20 puffs; isoproterenol, four puffs; carbuterol, four puffs; isoproterenol, 20 puffs; and carbuterol, 20 puffs. The puff was delivered by a standard metered aerosol; each puff of isoproterenol spray contained 75 mug of isoproterenol sulfate, and each puff of carbuterol spray contained 100 mug of carbuterol hydrochloride. Tracheal mucous velocity was not changed by receiving Freon, but administration of both isoproterenol and carbuterol caused a significant increase in this measurement, with peak increases ranging from 74 to 111 percent above control values. The duration of action for four and 20 puffs of isoproterenol and for four puffs of carbuterol was two hours. Twenty puffs of carbuterol increased tracheal mucous velocity for three hours. Administration of carbuterol effected a slightly larger increase in cardiac output than isoproterenol. The duration of action for the increased cardiac output was shorter than the duration of action for the increased tracheal mucous velocity. These studies indicate that beta-adrenergic agonists may have an important role in improving mucous transport in patients with chronic obstructive pulmonary disease in whom mucociliary clearance is depressed.

Adrenergic beta-Agonists↗
PubMed1976

The effect of an extraluminal transducer on the reproductive capability of the rabbit.

An extraluminally attached microminiature force transducer, designed for reproductive tract contractility measurements, was investigated in terms of its effects on the physiology of the uterotubal junction in the rabbit. The presence or attachment process of the extraluminal force transducer (EFT) did not affect the rate of pregnancy or the number of embryonic implantation sites whether the attached device was silicone rubber or polyethylene-encased. The uterotubal junction was able to retain the blastocyst for the required time after mating, while an examination of postembryonic mortality revealed a rate of one resorption in some experimental groups. The gestation period was unaffected by the EFT, ranging from 30 to 40 days with a mode of 32, while histologic examinations revealed formation of a thin fibroblastic layer, some increased vascularity, and no abnormal leukocytic accumulation.

Animals↗
PubMed1975

Massive deposition of mineral oil after prolonged ingestion.

A patient in whom prolonged mineral oil (liquid paraffin) ingestion caused the deposition of this material in the small intestine, abdominal lymph nodes, the liver, spleen and lungs, is described. The results of chemical and histochemical identification of the isolated material are presented. A description of the gross and microscopic pathology is followed by a brief consideration of some aspects of the subject of mineral oil ingestion. Prolonged unrestricted ingestion of mineral oil is dangerous and may cause structural and functional abnormalities which lead to severe malnutrition and death.

Humans↗
PubMed1975

The effect of prolonged lithium carbonate administration on the thyrotrophin and prolactin response to thyrotrophin-releasing hormone.

Thyrotrophin (TSH) and prolactin (PRL) responses to intravenous thyrotrophin-releasing hormone (TRH) were measured in euthyroid patients suffering from psychiatric disease on long-term lithium carbonate (LC) and phenothiazine therapy. These responses were retested after oral tri-iodothyronine (T3) 120 mug/day had been given for a week. The raised basal TSH and the suppression of the exaggerated responses to TRH by T3 found in some of the patients suggest a mild disturbance of thyroid function in patients on long-term LC therapy, even in the face of clinical euthyroidism and otherwise normal thyroid function. Basal serum PRL levels and the responses to TRH were elevated in 2 of 5 patients, probably associated with phenothiazine administration. In all 5, a moderate blunting of the PRL responses after TRH was produced by T3. The suppressive effect of T3 on TRH-induced PRL responses was unexpected and suggests a modifying role of thyroid hormones on PRL secretion, although further studies are needed to confirm this possibility.

Female↗
PubMed1975

Somatostatin and serum gastrin in normal subjects and in patients with pernicious anaemia, chronic liver and renal disease.

The effects of somatostatin (growth hormone release inhibiting hormone) on basal gastrin were studied in patients suffering from pernicious anaemia and chronic renal and liver disease, and during sequential arginine/insulin-stimulated gastrin release in normal subjects. When basal gastrin concentrations were normal (10-50 pg/ml) in controls and in patients who were in renal and liver failure, somatostatin had no effect on gastrin levels. Raised basal gastrin levels in pernicious anaemia and in 2 cases of chronic renal disease, were significantly inhibited by somatostatin with a half-life (T 1/2) of 3-4 minutes. Arginine infusion caused an insignificant rise in serum gastrin which was unaffected by somatostatin, whereas insulin hypoglycaemia significantly stimulated gastrin release, which was inhibited by somatostatin.

Adult↗
PubMed1975

Failure of adrenergic alpha and beta receptor blockade to elevate the TSH and prolactin response to TRH in hyperthyroidism.

The effects of adrenergic alpha and beta receptor blockade on the thyrotrophin and prolactin responses to TRH were studied in groups of hyperthyroid patients who received either oral propranolol and phenoxybenzamine or intravenous propranolol and rogitine. The flat TSH and prolactin responses to TRH in the untreated hyperthyroid patients were not altered by oral or intravenous adrenergic alpha and beta receptor blockade suggesting that catecholamines do not play a major role in the feedback suppression of TSH and prolactin in hyperthyroidism.

Adrenergic alpha-Antagonists↗
PubMed1975

Tracheal mucous transport in experimental canine asthma.

Tracheal mucous velocity (TMV) was measured in experimental canine asthma. All 10 sensitive dogs exposed to an aerosol of Ascaris suum extract showed a decrease in TMV to about one-third of base-line values within 45 min whereas only half of them (reactors) responded with bronchospasm as measured by a significant reduction in specific respiratory system conductance (SGrs). Mean TMV remained decreased at the end of the 2-h observation period when mean SGrs had returned to base-line values in the reactors. Neither TMV nor SGrs changed in nonsensitive animals who inhaled ragweed antigen. Aerosols of acetylcholine and histamine increased TMV thereby excluding these mediators as responsible for the impairment of mucous transport in asthma. Nebulization of A. suum antigen together with a selective antagonist of slow reacting substance of anaphylaxis (srs-a) produced a marked increase of TMV in all dogs regardless of whether or not bronchospasm was elicited. This suggests that the observed decrease in TMV may be related to the release of SRS-A during the immunologic reaction.

Animals↗
PubMed1975

Diffusing capacity, membrane diffusing capacity, capillary blood volume, pulmonary tissue volume, and cardiac output measured by a rebreathing technique.

A rebreathing method for estimating diffusing capacity, membrane diffusing capacity, pulmonary capillary blood volume, pulmonary capillary blood flow, and pulmonary tissue volume consists of rebreathing into a bag for 15 sec while acetylene, (18O)-carbon monoxide, oxygen, and helium are continuously sampled by a mass spectrometer. Because the masses of carbon monoxide and nitrogen are nearly identical at 28, it was necessary to use a stable isotope, C18O, to distinguish this gas with the mass spectrometer. Comparison of the pulmonary capillary blood flow by the rebreathing technique with the simultaneously obtained indicator dilution measurement in anesthetized dogs revealed good agreement. Estimations of pulmonary tissue volume appeared to be quite reproducible and consistent; the values tended to be somewhat smaller and less variable among normal subjects than reported by other investigators. After subtraction of capillary blood volume, tissue volume was 311 plus or minus 73 ml at rest and increased significantly to 352 plus or minus 61 ml at 75 watts of exercise. Pulmonary tissue volume in dogs using the rebreathing method averaged 9.2 ml per kg of body weight, a mean comparable to previously reported estimates using the ether plethysmographic method. The slope of pulmonary capillary blood flow (cardiac output in normal subjects) as a function of oxygen consumption during exercise in normal subjects of 0.0060 times oxygen consumption in milliliter per min was identical to published values. The rebreathing technique provides a rapid, reliable, noninvasive method for estimating pulmonary hemodynamic parameters.

Acetylene↗
PubMed1975

Disappearance rates of plasma growth hormone after intravenous somatostatin in renal and liver disease.

Plasma immunoreactive growth hormone (hGH) was measured before, during and after the administration of intravenous somatostatin to 3 patients with chronic renal failure and 4 with severe liver disease who had elevation of basal hGH. During somatostatin infusion, the hGH levels declined acutely in a linear fashion when log hGH was plotted against time. Rather surprisingly, the plasma hGH half disappearance time (t 1/2) was 27 min and 18 min in liver and renal disease respectively. These values do not differ from data obtained on normal subjects using exogenous hGH, labelled or unlabelled. Control data on normal subjects using this technique are not available as it was not possible to measure subnormal levels of plasma hGH with the required precision. It is possible that our findings of plasma hGH T 1/2 in liver and renal disease within the normal range reported using exogenous hGH might suggest that high levels of plasma hGH found in these two diseases are primarily caused by hypersecretion rather than impaired clearance.

Growth Hormone↗
PubMed1975

Effect of cuffed endotracheal tubes on tracheal mucous velocity.

The inflated cuffed endotracheal tube produces a significant depression of tracheal mucous velocity in anesthetized dogs after one hour. This effect occurs with bot low and high compliance cuffs but is not observed with an uncuffed tube. This phenomenon is another factor that must be considered in establishing criteria for the frequency of cuff deflation in patients supported by mechanical ventilators.

Animals↗