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Biomedical subjects

A Rogers

Publications and source records attributed to A Rogers.

At least 163 records · Page 9Linked to original sources
PubMed1987

Postpropranolol vasodilation in adrenalectomized glucocorticoid hypertensive rats.

Acute beta-adrenoreceptor blockade results in an enhanced blood pressure-lowering effect in glucocorticoid hypertensive rats in the absence of the adrenals. To evaluate the possible mechanism of this enhanced blood pressure-lowering effect, systemic and regional hemodynamics were determined by the radioactive microsphere technique before and after propranolol administration in bilaterally adrenalectomized (AX) and sham-operated (SH) glucocorticoid hypertensive rats. Propranolol decreased mean blood pressure (BP) and heart rate (HR) to a greater extent in the AX animals. In response to propranolol, cardiac output (CO) decreased equally in both the AX and SH animals. Regional vascular responses to propranolol were similar between the AX and SH animals, except in muscle. In muscle propranolol significantly decreased blood flow and increased resistance in the SH animals. In marked contrast, in the AX animals propranolol significantly increased blood flow and decreased vascular resistance. The results of this study show that in adrenalectomized glucocorticoid hypertensive rats, the enhanced BP lowering effect of acute beta-adrenoreceptor blockade is not mediated by changes in CO. Additionally, in glucocorticoid hypertensive rats acute beta-adrenoreceptor blockade causes selective vasodilation in skeletal muscle.

Adrenalectomy↗
PubMed1986

Seroepidemiology of Campylobacter pyloridis.

A total of 1158 sera were tested by an enzyme linked immunosorbent assay (ELISA) for IgG and IgA antibodies to Campylobacter pyloridis. When used to test sera from gastroendoscopy patients this method had a sensitivity of 91% and a specificity of 75%. Ninety-eight of 108 infected patients (91%) were seropositive whereas only 23 of 92 (25%) uninfected patients were seropositive (p less than 0.001). Positive serology was also associated with histological gastritis (p less than 0.001). When sera from occupational groups were compared to random blood donor sera, meat workers, freezing works veterinary surgeons and pest control officers had significantly higher seropositivity. Cook Island (33 of 85 (39%)), Samoan (57 of 129 (44%)) and Tongan (39 of 56 (70%)) blood donors also had greater seropositivity than random blood donors (15 of 102 (15%)), (p less than 0.001 for all three ethnic groups). Seropositivity increased with age. The results indicate that C pyloridis infection is common among certain groups within New Zealand. The implication of this finding with respect to the hypothesis that C pyloridis is aetiologically related to dyspepsia and peptic ulcer disease is discussed.

Adolescent↗
PubMed1986

Hemodynamic effects of a new type III phosphodiesterase inhibitor (CI-914) for congestive heart failure.

Hemodynamic response after intravenous and oral administration of a new phosphodiesterase inhibitor, CI-914, was studied in 13 patients with severe congestive heart failure. Comparable significant increases in cardiac index of 26% (p less than 0.01) and 19% (p less than 0.02) after intravenous and oral administration were observed. Systemic vascular resistance, right atrial and pulmonary artery wedge pressure decreased significantly after intravenous drug administration. Although similar changes occurred after oral administration, they were not statistically significant. Peak CI-914 plasma concentration occurred 2.3 +/- 2.2 hours after oral drug administration and exhibited measurable hemodynamic effects for up to 10 to 12 hours. Seven of the 13 patients received long-term oral CI-914 for as long as 12 weeks and exhibited an improvement in New York Heart Association functional class and exercise capacity. Five patients died with progressive heart failure, 1 patient died suddenly and 1 died of sepsis. The drug was well tolerated and appears to have potential as a cardiotonic agent.

Administration, Oral↗
PubMed1986

Low-dose (diagnostic-like) x-ray as a cocarcinogen in mouse colon carcinoma.

To test the hypothesis that low-dose (diagnostic-like) radiation may play the part of a cocarcinogen in inflammatory bowel disease, we used four groups of BALB/C mice, (a control, dimethylhydrazine, dimethylhydrazine plus low-dose radiation, and low-dose radiation). We found no protective or carcinogen effects of the radiation in combination with dimethylhydrazine compared to dimethylhydrazine alone. This type of negative experimental finding is important in that individuals with inflammatory bowel disease have many diagnostic x-rays throughout life.

Animals↗
PubMed1986

Parameterized multistate population dynamics and projections.

"This article reports progress on the development of a population projection process that emphasizes model selection over demographic accounting. Transparent multiregional/multistate population projections that rely on parameterized model schedules are illustrated [using data primarily from a number of developed countries, particularly Sweden], together with simple techniques that extrapolate the recent trends exhibited by the parameters of such schedules." The author notes that "the parameterized schedules condense the amount of demographic information, expressing it in a language and variables that are more readily understood by the users of the projections. In addition, they permit a concise specification of the expected temporal patterns of variation among these variables, and they allow a disaggregated focus on demographic change that otherwise would not be feasible."

Demography↗
PubMed1986

I.v. infusion of opioids for cancer pain: clinical review and guidelines for use.

To assess the safety, efficacy, and use of continuous iv infusion (CI) of opioids for cancer pain, we reviewed the clinical experience of 36 patients who received 46 CIs. CI was always preceded by a period of repetitive dosing of opioids. Morphine was used in 36 CIs, methadone in four, hydromorphone in four, oxymorphone in one, and levorphanol in one. Mean doses during CI were the morphine equivalent of 17 mg/hour (range, 0.7-100) at the start, 69 mg/hour (range, 4-480) at the maximum, and 52 mg/hour (range, 1-480) at termination. Pain relief was acceptable during 28 CIs, unacceptable during 17, and unknown during one. There were few toxic effects other than sedation. Twenty-five patients died, 12 resumed im or oral opioids, six continued CI with a different opioid (yielding analgesia in two), and outcome was undetermined in three. This review suggests that (a) CI is safe, (b) analgesia may require rapid escalation of infusion rates, (c) patient response varies and lack of acceptable analgesia may occur in up to one-third, (d) ineffective CI with one drug may be followed by success with another, (e) CI should be preceded by a period of repetitive iv boluses with the same drug, and (f) guidelines can be developed which incorporate pharmacokinetic principles.

Adolescent↗
PubMed1985

Effect of insulin on renal phosphorus handling in the rat: interaction with PTH and nicotinamide.

Previous studies suggested an antiphosphaturic action of insulin. However, effects of parathyroid hormone (PTH), anti-natriuresis, or other variables were not vigorously controlled. Recently it has been suggested that nicotinamide restores phosphaturia in several antiphosphaturic states. Clearance studies were therefore performed in acutely parathyroidectomized rats to test the hypothesis that insulin abolishes the phosphaturic action of PTH and that this effect is prevented by nicotinamide. Superimposition of euglycemic hyperinsulinemia on PTH infusion (plasma insulin 19.1 +/- 2.7 vs. 9.8 +/- 1.1 microU/ml, P less than 0.05) during steady-state Pi excretion decreased fractional excretion (FE) of Pi compared with PTH-infused controls (3.16 +/- 0.61 vs. 18.02 +/- 0.81%, P less than 0.001). Renal cortical NAD+ was lower in the former than the latter group (455 +/- 22 vs. 689 +/- 30 pmol/mg, P less than 0.01). Nicotinamide pretreatment prevented the antiphosphaturic action of insulin and the decrease in cortical NAD+ in both the presence and absence of exogenous PTH. These studies offer direct evidence that in acutely parathyroidectomized rats insulin can abolish the phosphaturic action of PTH, independent of glomerular filtration rate, the filtered loads of Pi and glucose, FENa+, and cAMP excretion, an effect that is prevented by nicotinamide pretreatment. In the absence of nicotinamide pretreatment, superimposition of insulin on PTH infusion was associated with a decrease in renal cortical NAD+. A role for intracellular NAD+, probably indirect, in the antiphosphaturic action of insulin is suggested.

Animals↗
PubMed1985

Analysis of asbestos fibers and asbestos bodies in tissue samples from human lung. An international interlaboratory trial.

In order to compare methods of counting asbestos fibers in lung tissue, seven laboratories participated in an interlaboratory trial in which tissue samples from five human lungs were analyzed. In some laboratories, fiber concentrations were assessed with the light microscope and, in others, with either scanning or transmission electron microscopes. Within each laboratory the ranking of the results was similar, but there were marked differences in the absolute values obtained by the different laboratories. It is concluded that the laboratories participating in this trial appear to produce internally consistent results, but there is difficulty in directly comparing results from one laboratory to the next.

Aged↗
PubMed1984

The restoration of medical ethics.

The ethical behaviour of doctors has been influenced by recent social and political changes. This paper discusses some of the changes which may have resulted from two far-reaching changes, a major political change, the nationalisation of medicine in the National Health Service (NHS), and a social change, the establishment of the permissive society. Some of the ethical consequences of these changes which are not considered of benefit to the profession or its patients are discussed. The recognition of these changes and their open debate is now essential so that the restitution of professional standards may take place.

Ethics↗
PubMed1983

Assortative mating and the segregation variance.

Feldman and Cavalli-Sforza (Theoret. Pop. Biol. (1979), 15, 276-307; (1981), 19, 370-377) have emphasized the role of the segregation variance in models of assortative mating for continuous characters. This note examines its behavior in the context of a general additive model. Using known results concerning the effects of assortative mating and selection on genic variance and correlations among uniting gametes it is shown that the effects of these processes on segregation variance wil be small if the effective number of loci is large. Thus models in which the segregation variance remains constant are approximate descriptions of the behavior of characters determined by many loci.

Analysis of Variance↗
PubMed1983

Patterns of family migration: two methodological approaches.

"It is widely recognized that many internal migrations are undertaken by individuals whose moves are dependent on those of others. For example, children migrate with their parents and wives with their husbands. This paper suggests two formulations of family migration that permit the introduction of such family dependencies into the population projection process."

Demography↗
PubMed1983

Migration and settlement: a multiregional comparative study.

"In 1976, the International Institute for Applied Systems Analysis initiated a study of migration and population distribution patterns in its seventeen member nations. In each country, the analysis was carried out by national scholars using techniques of multiregional demography. In this paper the authors describe the organization of the study, discuss the data bases used, evaluate the main results obtained, and review some of the methodological research that has been generated by the study. Among the...conclusions are recommendations for researchers wishing to carry out a multiregional demographic analysis." Consideration is given to national and subnational patterns of mortality, fertility, and migration; age composition; and regional population distribution.

Age Distribution↗