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Biomedical subjects

C A Henry

Publications and source records attributed to C A Henry.

At least 37 records · Page 2Linked to original sources
PubMed1990

Central infusion of aldosterone increases blood pressure by mechanisms independent of Na retention.

Experiments were performed to test the hypothesis that Na retention and Na in the diet are not required to initiate central aldosterone induced hypertension. Rats were fed either standard rat chow or Na-deficient diet and infused intracerebroventricularly (i.c.v.) with aldosterone (28 ng/h) dissolved in artificial cerebrospinal fluid (vehicle) or vehicle alone. In Na-replete rats the central infusion of aldosterone did not promote Na or water retention, prior to increases in systolic blood pressure (SBP). Infusion of aldosterone in Na-deficient rats also initiated a rise in SBP, although the response was delayed. In neither group of rats did aldosterone infusion significantly change plasma Na, K, renin, norepinephrine (NE) or vasopressin (AVP) concentrations. There was no significant increase in plasma aldosterone concentration in Na replete rats centrally infused with aldosterone. Infusion of vehicle had no effect on SBP. We conclude that central aldosterone infusion initiates an increase in blood pressure by a mechanism independent of Na retention. Furthermore, increased concentrations of systemic renin, vasopressin, and activation of the sympathetic nervous system do not appear to be involved in maintaining hypertension.

Aldosterone↗
PubMed1988

Nitroglycerine/N-acetylcysteine in the management of unstable angina pectoris.

N-acetylcysteine (NAC) has been shown to potentiate the haemodynamic and antiplatelet effects of nitroglycerine (NTG) in man, and to limit the development of haemodynamic tolerance to NTG. These effects may be mediated. by the formation of S-nitroso-NAC, which induces vasodilation and strongly inhibits platelet aggregation. In a randomized double-blind study in 46 patients with severe unstable angina pectoris unresponsive to standard treatment (including cutaneous nitrates and calcium antagonists in 45 patients) we compared the effects of intravenous (IV) NTG with those of IV NTG combined with IV NAC (5 g 6 hourly). Treatment with NTG/NAC (24 patients) was associated with a similar frequency of episodes of chest pain as treatment with NTG alone (22 patients), but somewhat fewer increments in infusion rate for pain control (10 vs 17; P NS). The NTG/NAC group had a significantly lower incidence of acute myocardial infarction than the NTG/placebo group (3 vs 10 patients; P = 0.013). Symptomatic hypotension occurred frequently in the NTG/NAC group (7 vs 0 patients; P = 0.006). It is concluded that combined administration of NTG and NAC in patients with unstable angina pectoris may augment the clinical efficacy of NTG, largely by reducing the incidence of acute myocardial infarction. However, the high incidence of severe hypotension with NTG/NAC suggests that this regimen should be used with some caution.

Acetylcysteine↗
PubMed1988

Combined use of nitroglycerin and N-acetylcysteine in the management of unstable angina pectoris.

The vasodilator effects of nitroglycerin (NTG) are mediated via activation of guanylate cyclase; this process is believed to require the availability of free sulfhydryl groups. Previous studies in man have shown that the sulfhydryl donor N-acetylcysteine (NAC) potentiates the systemic and coronary vasodilator effects of NTG. Furthermore, interaction of NTG and NAC may lead to the formation of S-nitroso-NAC, which strongly inhibits platelet aggregation. The effects of intravenous NTG combined with intravenous NAC (5 g 6 hourly) were compared with those of intravenous NTG alone in a double-blind trial in 46 patients with severe unstable angina pectoris unresponsive to conventional treatment, which included calcium antagonists and cutaneous nitrates in all but one patient. Treatment with NTG/NAC (24 patients) and that with NTG alone (22 patients) was associated with a similar frequency of episodes of chest pain and of increments in NTG infusion rate for pain control (10 vs 17; p = NS). The NTG/NAC group had a significantly lower incidence of acute myocardial infarction than the NTG/placebo group (three vs 10 patients; p = .013). Symptomatic hypotension occurred frequently in the NTG/NAC group (seven vs 0 patients; p = .006). Lactate-pyruvate ratios and venous NTG concentrations were not significantly affected by NAC. Subsequently, another 20 consecutive patients were treated with intravenous NTG and continuously infused NAC (10 g/day). Seven remained pain free during the first 24 hr of NTG infusion; 11 required increments in NTG infusion rate for pain control. Acute myocardial infarction occurred in one patient, while none developed symptomatic hypotension.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcysteine↗
PubMed1988

Primary lymphoma of the large intestine.

Three cases of primary colonic lymphoma are presented and the literature for this disease is reviewed. Colonic lymphoma occurs in from 0.5 to 2 per cent of all cases of neoplastic disease of the colon, and comprises 15 to 20 per cent of cases of primary gastrointestinal lymphoma. The disease can occur at any age, from 3 years to 89 years; the average age is 50 years. Men are affected twice as often as women. The disease most commonly presents as a painful abdominal mass. The cecum is the area of involvement in 70 per cent of cases. The tumors are usually large, averaging over 7 centimeters. The most common histological types are histiocytic or lymphocytic tumors. Surgery is the principle treatment mode; about half are thought to be potentially curable at the time of surgical exploration. The role of adjuvant therapy has not yet been clearly defined, although data from some studies indicate increased survival in those patients given adjuvant radiation therapy. Survival is decreased in patients with tumors larger than 5 centimeters or with histiocytic cell type. Overall 5-year survival is 39 per cent.

Aged↗
PubMed1987

Isolation of hepatocytes from postnatal mice.

A method for the isolation of hepatocytes from postnatal (1- to 3-week-old) mice has been developed. Cell isolation was carried out by retrograde perfusion of the liver with a collagenase-containing bicarbonate buffer. Viable cells were separated by selective adsorption onto collagen membranes. Cell viability was assessed by measuring ATP and glutathione content, lactate:pyruvate ratio, and the rate of protein synthesis. Comparisons of these parameters were made with those in cells isolated from adult mice and with values in whole liver. These hepatocytes were capable of metabolizing acetaminophen to its known hepatic conjugates and were susceptible to acetaminophen toxicity. This procedure for isolating mouse hepatocytes should be useful for the study of hepatic drug metabolism and its relationship to toxicity in the postnatal mouse.

Acetaminophen↗
PubMed1987

Relationships of serum opsonins and complement in human experimental gingivitis.

This study assessed the phagocytosis of polymorphonuclear neutrophils and the opsonic capacity of serum in experimental human gingivitis. Relationships were sought among these two measurements, clinical indices of gingivitis and complement-related opsonins. Measurements of chemiluminescence provided an index of phagocytosis and of opsonic capacity. Test group Plaque Index scores were higher than the control group on Days 7, 14, and 21, while the Gingival Index of the test group was elevated only on Day 21. Phagocytosis of test subjects' PMNs and opsonic capacity of their sera were no different from that of the controls'. Levels of C3 in both nonactivated and activated sera of the test group were significantly lower than that of the control group only on Day 14. In the test group, differences of per cent C3 conversion occurred between Days 14 and 21, and Plaque Index scores were inversely correlated with the order of per cent C3 data on these same days. Our results also indicate that complement contributes significantly to the serum opsonic capacity. The levels of developing plaque and subsequent gingival inflammation are apparently related to the degree of complement activation.

Adult↗
PubMed1985

Microbiology teaching in American dental schools.

A comprehensive questionnaire on current practices relevant to teaching microbiology to dental students was sent to all dental schools in the United States. The survey collected information on resources available, modes of teaching, and evaluation processes. Seventy percent (42/60) of the schools responded. Great variation was found in the teaching of microbiology largely due to the variety of educational resources, perspective of subject matter by the faculty, and the backgrounds of entering students. Data are presented that document the integration of microbiology with other courses, placement of microbiology in the curriculum, class attendance policies, availability of advanced selective and/or elective courses, and National Board reviews. These and other data indicate some prevailing trends in the teaching of microbiology to dental students.

Curriculum↗
PubMed1984

Neutrophil chemotaxis and periodontal health relationships of young adult people in Thailand.

Polymorphonuclear neutrophils (PMN) from 26 young patients with periodontitis exhibited about 10 per cent less chemotaxis compared to healthy-matched control subjects. This modest but significant reduction of PMN chemotaxis occurred when the attractants were derived from either autologous or heterologous sera. The lower chemotaxis function was attributable to the nature of the PMN in periodontitis and not to the capacity of the patients' serum to generate chemo-attractants. Random migration of PMN was the same in both patients and controls. Kinetic studies with endotoxin-activated human sera showed no difference between the PMN of two periodontitis patients and their controls. No significant correlations were found between chemotaxis and the clinical periodontal indices; however, PMN chemotactic values were lower in localized periodontitis than in the generalized form of the disease.

Adult↗
PubMed1984

Neutrophil chemi-luminescence and opsonic activities of young people with periodontitis in Thailand.

The polymorphonuclear neutrophils (PMN) produced significantly-higher chemi-luminescence (CL) peak values than neutrophils of healthy-paired controls when each population of cells was challenged with zymosan pre-opsonized with autologous serum. This enhanced CL was not attributable to the metabolic activity of the cells, but was shown, by cross-over experiments and additional testing with a single source of cells, to be directly associated with the opsonizing capacity of the patient's serum. The results suggest that peripheral PMN from young periodontitis patients have oxidative metabolic activities similar to subjects free of this disease, and that the enhanced PMN metabolism of patients may be due to a corresponding increase of serum opsonins.

Adult↗
PubMed1977

The effect of adsorption on the acid production of caries and noncaries-producing streptococci.

Eighteen different Streptococcus strains including S mutans, sanguis, mitis, salivarius, bovis, and 2F2, were assayed for their relative adsorption to synthetic hydroxyapatite and for quantities of lactic acid produced while in the adsorbed state. The results indicated that all S mutans and some S sanguis have an enhanced metabolic activity while adsorbed to hydroxapatite as compared to control suspensions without hydroxyapatite.

Adsorption↗