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Biomedical subjects

R Donnelly

Publications and source records attributed to R Donnelly.

135 records · Page 8Linked to original sources
PubMed1987

An evaluation of the pharmacodynamics and pharmacokinetics of nicardipine combined with enalapril in essential hypertension.

Recent observations suggest that calcium antagonists may enhance the antihypertensive effects of angiotensin-converting enzyme (ACE) inhibitors. Twelve essential hypertensives who had blood pressures greater than 160/90 after a minimum of 6 weeks of monotherapy with the ACE inhibitor enalapril 20 mg daily received additional treatment with nicardipine 30 mg t.i.d. and placebo, each for 2 weeks, in a double-blind crossover study. The combination of nicardipine with enalapril was well tolerated. The addition of the first dose of nicardipine was associated with significant reductions (p less than 0.05) in blood pressure during the first 4 h: from a baseline of 165/99 to 128/80 (supine) at 2 h after nicardipine as compared with 167/101-146/90 following placebo. Two weeks of combined treatment with nicardipine and enalapril significantly reduced the predosing blood pressure, 12 h after the last dose of nicardipine (158/96 as compared with 172/106 with placebo), and there were further significant reductions in blood pressure during the subsequent dosage interval. The profile of plasma ACE inhibition and the pharmacokinetics of enalaprilat were unaffected by the addition of nicardipine. These results suggest that nicardipine and enalapril are an effective and well-tolerated antihypertensive combination.

Adult↗
PubMed1987

Acute and chronic ketanserin in essential hypertension: antihypertensive mechanisms and pharmacokinetics.

1. In nine patients with essential hypertension, following single and multiple doses of ketanserin, assessments were made of blood pressure and heart rate, QT interval, and pressor responses to phenylephrine and angiotensin II. 2. Significant reductions in blood pressure occurred for 6 h after the first dose, on average 23/14 mm Hg supine, and there was a comparable antihypertensive effect after 1 month's treatment. 3. There were small but significant rightward shifts (1.5 to 2-fold) in the phenylephrine pressor-response curves but no changes in the responsiveness to angiotensin II. 4. The QT interval (QTc) was significantly increased after 1 month's treatment: at 1 h after dosing 334 +/- 32 ms after 1 month of ketanserin compared with 302 +/- 31 ms after placebo. 5. The elimination half-life and AUC for ketanserin were both significantly increased at steady state compared with the first dose: respectively 13.4 vs 4.3 h for half-life and 830 vs 437 ng ml-1 h for AUC. 6. Ketanserin had no significant effects on baroreflex function, plasma renin activity, aldosterone, catecholamines and 24 h urinary excretion.

Adult↗
PubMed1987

Enalapril in essential hypertension: the comparative effects of additional placebo, nicardipine and chlorthalidone.

The effect of adding placebo, a calcium antagonist, nicardipine and a thiazide diuretic, chlorthalidone, each for 2 weeks, to ongoing treatment with the ACE inhibitor, enalapril was evaluated in seven patients with essential hypertension. Compared with placebo, nicardipine and chlorthalidone both significantly enhanced the antihypertensive effect of enalapril: average blood pressure reductions over 8 h were respectively 26/16 and 33/17 mm Hg (supine) but the time-course of these augmented effects was significantly different. In particular, blood pressure control with the addition of nicardipine, despite apparently being at steady state, was significantly attenuated during the latter part of the dosage interval and therefore was less well sustained at 24 h. In contrast, an effect throughout 24 h appeared possible with the chlorthalidone-enalapril combination.

Acetylcholinesterase↗
PubMed1986

Effect of isoprinosine on sialylation of interleukin-2.

The effects of Isoprinosine (ISO) on interleukin-2 (IL-2) production by human peripheral blood mononuclear cells (PBMC) were investigated. Treatment (of human PBMC) with ISO enhanced IL-2 production by PBMC from 7 of 10 normal individuals. However, no augmentation of IL-2 production was observed when cultures of HUT-78 cells, a human leukemic T cell line, were treated with ISO. IL-2 purified from supernatants of human PBMC treated with ISO exhibited pI values of 5.5 and 6.4. IL-2 prepared from untreated PBMC exhibited a single pI value of 8.2. The pI value of IL-2 prepared from ISO-treated PBMC shifted to 8.2 after treatment with neuraminidase, demonstrating that the IL-2 molecules isolated from ISO-treated PBMC possessed sialic acid. The pI values of the IL-2 isolated from ISO-treated and untreated HUT-78 culture supernatants were identical (pI = 7.8) and were not modified by neuraminidase treatment. These results suggest that the increase in IL-2 production following treatment of PBMC with ISO may be mediated through the activation of a distinct subset of IL-2 producing cells. Furthermore, the sialylation of IL-2 may be of physiologic and immunopharmacologic importance.

Adjuvants, Immunologic↗
PubMed1983

Dietary ascorbic acid and resistance to experimental renal candidiasis.

Guinea pigs were maintained for various periods of time on low (0.5 mg/day), intermediate (20 mg/day), or high (100 and 500 mg/day) levels of dietary ascorbic acid. Animals in each experimental group were challenged with Candida albicans via cardiac injection, and the course of infection in the kidneys was assessed. The results show that the animals receiving only 0.5 mg of ascorbic acid per day were significantly more susceptible to the infection than animals maintained on any higher level of dietary ascorbic acid. The greater susceptibility of the guinea pigs in the 0.5-mg level group was evident, however, only during "early" stages of the infection (until about day 3). Guinea pigs receiving high levels of dietary ascorbic acid were no more resistant at any time after infection, or with any challenge dose, than those receiving an intermediate dietary level. Although these data suggest that vitamin C may be involved in resistance to candidiasis, tissue levels of ascorbic acid do not change significantly with time after infection. These results indicate that low levels of dietary ascorbic acid increase susceptibility to candidiasis, yet high (or "megadose") levels of dietary vitamin C do not show any effect on resistance to this microorganism.

Animals↗
PubMed1983

Liver dysfunction associated with gold therapy for rheumatoid arthritis.

Hepatic toxicity is rarely associated with gold therapy. Three patients with rheumatoid arthritis who developed jaundice during the course of chrysotherapy are described. Jaundice occurred both early and late in the course of therapy. differing grades of severity of dysfunction were encountered. Liver biopsy revealed intrahepatic cholestasis. Significance of jaundice occurring during gold therapy is discussed.

Aged↗
PubMedDate not supplied

Expression of the beta 3-adrenoceptor gene polymorphism (Trp64Arg) in obese diabetic and non-diabetic subjects.

1. A missense mutation (Trp64Arg) in the beta 3-adrenoceptor (beta 3-AR) gene has been associated with weight gain, insulin resistance and earlier-onset non-insulin-dependent diabetes mellitus (NIDDM), but the strength of these associations varies considerably between populations and the functional significance of Trp64Arg remains unclear. 2. The Trp64Arg mutation was investigated in obese NIDDM (n = 50) and obese non-diabetic (n = 53) subjects by polymerase chain reaction (PCR) amplification of genomic DNA and digestion of the 210 bp product by BstOI. The Arg allele was found in 22.3% of all subjects, but there were no homozygotes for the mutation. Non-diabetic subjects heterozygous for the mutation were more obese and Trp/Arg diabetics had a slightly younger age of onset of NIDDM (47 vs 51 years, respectively), but there were no significant differences in mutation frequency between the two groups. Metabolic parameters (e.g. fasting lipids and glycaemic control) were similar among diabetic subjects with and without the Trp64Arg mutation. 3. In conclusion, the frequency of the Trp64Arg mutation of the beta 3-AR was higher in this obese population compared with some previous studies, but there was no evidence that Trp64Arg confers an increased susceptibility to NIDDM among obese insulin-resistant subjects or that diabetics with the mutation fare worse in terms of lipid or glucose metabolism.

DNA↗