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Biomedical subjects

G Long

Publications and source records attributed to G Long.

At least 55 records · Page 3Linked to original sources
PubMed1991

Effects of ACE inhibition on renal haemodynamics in essential hypertension and hypertension associated with chronic renal failure.

Angiotensin II has many actions in the kidney, including regulation and distribution of renal circulation and glomerular filtration, as well as effects on mesangial contraction and on the filtration coefficient. The reduction in circulating and intrarenal angiotensin II by angiotensin converting enzyme (ACE) inhibitors in essential hypertension is associated with a significant increase in renal blood flow and a decrease in filtration fraction, without changes in glomerular filtration rate. In addition, administration of ACE inhibitors can reduce proximal sodium reabsorption via changes in peritubular hydrostatic and oncotic forces resulting from the fall in postglomerular capillary resistance. In severe hypertension the state of the renal vasculature does not allow ACE inhibition to induce similar haemodynamic changes and, therefore, it cannot contribute to renal sodium handling that requires the recruitment of alternate mechanisms. In spite of this, ACE inhibitors may exert a protective effect on the renal function of patients with severe hypertension as well as in those with renal impairment, by lowering systemic and, probably, intraglomerular pressure, reducing proteinuria and slowing the progression of renal failure.

Adolescent↗
PubMed1985

Dose-response toxicity studies on tributoxyethyl phosphate orally administered to Sprague-Dawley rats.

The response of the peripheral nervous system to various dose levels of tributoxyethyl phosphate (TBOP) was investigated in Sprague-Dawley rats. Groups of randomized female and male rats (10 rats/gender/dose level) were administered a single oral dose of TBOP (1.0 to 3.2 g/kg for females; 1.0 to 9.0 g/kg for males). Physiological parameters were measured in surviving rats three weeks following TBOP administration. A significant reduction (p less than 0.05) in caudal nerve conduction velocity (NCV) was observed in both female and male rats. Light and electron microscopic examination of sciatic nerve sections showed degenerative changes in both myelinated and unmyelinated fibers of female (2.0 g/kg) and male (6.8 g/kg) groups. Advanced degeneration was observed only in the highest dose level of both genders (3.2 g/kg for females; 8.0 and 9.0 g/kg for males). Although similar morphological changes were observed in both genders, females were more susceptible than males to the toxic effects of this compound.

Administration, Oral↗
PubMed1984

Induction of electrophysiological and morphological changes in Sprague-Dawley rats fed tributoxyethyl phosphate.

The effects of a widely used trialkyl phosphate (TP), tributoxyethyl phosphate (TBOP), on the peripheral nervous system of Sprague-dawley (SD) rats were investigated. Male and female SD rats were administered this chemical by gavage over a period of 18 weeks (low dose: 0.25 ml kg-1; high dose: 0.50 ml kg-1). Electrophysiological changes observed at 18 weeks in all test animals included a significant reduction (P less than 0.001) in nerve conduction velocity and an important increase (P less than 0.001) of both relative (RRP) and absolute refractory period (ARP). Light and electron microscopic examination of sciatic nerve from all test animals showed the presence of degenerating myelin sheaths accompanied by axonal swelling. An advanced stage of degeneration was indicated by the presence of lamellated electron dense inclusions in unmyelinated nerve fibres.

Animals↗
PubMed1984

Subacute oral toxicity of tri-n-butyl phosphate in the Sprague-Dawley rat.

Tri-n-butyl phosphate was administered by gavage to male and female Sprague-Dawley rats for 14 consecutive days (low dose: 0.14 ml kg-1; high dose: 0.42 ml kg-1). Effects of this chemical were investigated at the end of the feeding period. Histopathological examination of the testes (high-dose group) showed the presence of microscopic degenerative changes in the seminiferous tubules. No other abnormal microscopic changes were observed.

Administration, Oral↗
PubMed1983

Millions of medical care dollars for indigents.

The medically indigent, a group traditionally underserved with health care, can obtain some needed free services from Hill-Burton facilities. These facilities (hospitals, nursing homes, clinics, and agencies) received Hill-Burton funds for their building programs and have, as a result, an obligation to provide a certain amount of uncompensated medical care to a defined medically indigent population. Health systems agencies (HSAS) or other interested agencies and groups can play an integral role in highlighting the Hill-Burton Program and helping the medically indigent obtain free care, This paper describes the Hill-Burton Program and explains how one HSA identified the Hill-Burton facilities in its area, determined the extent of their obligations, obtained allocation plans, and publicized and promoted the available health care services. From the interest shown by the community it was apparent that the HSA had provided a much needed and appreciated service that could be duplicated across the country by HSAS or other community groups.

Financing, Government↗
PubMed1983

Effects of tri-n-butyl phosphate on the peripheral nervous system of the Sprague-Dawley rat.

Tri-n-butyl phosphate, a widely used plasticizer and solvent, was orally administered to male and female Sprague-Dawley rats for 14 consecutive days (low dose: 0.28 mL/kg; high dose: 0.42 mL/kg). Effects of this industrial chemical were investigated on the peripheral nervous system of these animals. A significant (P less than 0.05) reduction in conduction velocity of caudal nerve was observed in high dose male rats. Electron microscopic examination of sciatic nerve showed morphological changes such as retraction of Schwann cell processes surrounding unmyelinated fibres in both sexes of high dose groups.

Animals↗
PubMed1981

The effect on heart rate of neuromuscular blockade reversal by pyridostigmine.

Pyridostigmine without atropine, pyridostigmine with atropine or neostigmine with atropine were used to antagonise neuro-muscular blockade induced by d-tubocurarine in forty otherwise healthy, female patients recovering from gynaecological surgery. Pulse rates fell significantly (P less than 0.01, control heart rate 72 +/- 18 beats/min (M +/- SD) to 55 +/- 13 beats/min) at ten minutes after pyridostigmine (10 mg/70 kg), necessitating administration of atropine (1.25 mg/70 kg) by fifteen minutes after pyridostigmine. After an initial rise in rate, pulse rates also fell significantly (P less than 0.01, control heart rate 70 +/- 12 beats/min to 44 +/- 11 beats/min) at fifteen minutes after injection of neostigmine (2.5 mg/70 kg) with atropine (1.25 mg/70 kg). By contrast when pyridostigmine and atropine were used together, pulse rates rose and then fell, but mean values never fell below control during a twenty-minute observation period. It was concluded that pyridostigmine should not be given alone, but requires the use of atropine to prevent bradycardia. This combination may, however, provide a more stable heart rate than that seen with neostigmine and atropine in usual doses, when these drugs are used to antagonise d-tubocurarine.

Adolescent↗
PubMed1979

Cutaneous and venous complications of pentazocine abuse.

A 55-year-old man with a two-year history of intramuscular pentazocine abuse had classical cutaneous findings as well as secondary venous thrombosis, which, to our knowledge, is previously undescribed. Histologic evaluation, including direct immunofluorescent microscopy, did not establish the mechanism of tissue destruction.

Humans↗
PubMed1976

Plasma protein binding and placental transfer of bupivacaine.

The maternal venous and umbilical venous plasma concentrations of bupivacaine were determined at delivery following epidural administration of the drug to 31 women in labor. In each case the umbilical venous plasma concentration of bupivacaine was lower than the maternal venous plasma concentration. There was no significant difference between the concentration of unbound bupivacaine in umbilical venous and maternal venous plasma at delivery. The difference in umbilical and maternal plasma concentrations of bupivacaine appears to be a consequence of greater bupivacaine binding to maternal than to fetal total plasma protein. The intersubject variation of the ratio of bupivacaine concentration in fetal plasma/bupivacaine concentration in maternal plasma was found to be related to individual variation in the extent of protein binding of bupivacaine in maternal and umbilical plasma and correlated positively with the variation of the ratio of total protein concentration in umbilical and maternal plasma.

Blood Proteins↗
PubMed1974

The effects of r- and K-selection on components of variance for two quantitative traits.

The genetic and environmental components of variance for two quantitative characters were measured in the descendants of Drosophila melanogaster populations which had been grown for several generations at densities of 100, 200, 300, and 400 eggs per vial. Populations subject to intermediate densities had a greater proportion of phenotypic variance available for selection than populations from either extreme. Selection on either character would be least effective under pure r-selection, a frequent attribute of selection programs.

Alleles↗