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Biomedical subjects

A McDonald

Publications and source records attributed to A McDonald.

At least 109 records · Page 6Linked to original sources
PubMed1989

Primary prevention of hypertension by nutritional-hygienic means. Final report of a randomized, controlled trial.

A 5-year trial involving 201 men and women with high-normal blood pressure at baseline demonstrated the ability to reduce the incidence of hypertension in participants randomized to nutritional-hygienic intervention compared with a control group. The incidence of hypertension was 8.8% among 102 intervention group participants vs 19.2% among 99 control group members. The odds ratio for the incidence of hypertension in the control group was 2.4. Mean trial blood pressure also was lower in the intervention compared with the control group (-1.2 and -1.9 mm Hg, respectively, for diastolic blood pressure at work-site and office visits and -1.3 and -2.0 mm Hg, respectively, for systolic blood pressure at the two sites). Net weight loss in the intervention group averaged 2.7 kg during the trial; sodium intake was reduced by 25% and reported alcohol intake decreased by 30%. The majority of intervention participants also reported an increase in physical activity. Effect on blood pressure was related particularly to degree of weight loss. Results indicate that even a moderate reduction in risk factors for hypertension among hypertension-prone individuals contributes to the primary prevention of the disease.

Adult↗
PubMed1988

Characterization and properties of nine human ovarian adenocarcinoma cell lines.

Four series of cell lines have been derived from patients with ovarian adenocarcinoma. Nine cell lines have been established at one from a solid metastasis. Six lines were derived from the ascites or pleural effusion of patients with poorly differentiated adenocarcinoma: PEO1, PEO4, and PEO6 from one patient, PEA1 and PEA2 from a second, and PEO16 from a third. Three lines (PEO14 and PEO23 from ascites and TO14 from a solid metastasis) were derived from a patient with a well-differentiated serous adenocarcinoma. Each set of cell lines was morphologically distinct. The five cell lines PEO1, PEO4, PEO6, PEA1, and PEA2 had cloning efficiencies on plastic of 1-2% and only a few cells in these lines expressed alkaline phosphatase or vimentin. Only a low percentage of these cells reacted with the monoclonal antibodies 123C3 and 123A8 but most reacted with OC125. Conversely the cell lines PEO14, TO14, PEO23, and PEO16 were characterized by low cloning efficiency values (less than 0.05%), marked expression of alkaline phosphatase and vimentin, and good reaction with 123C3 and 123A8 but not OC125. These four cell lines also exhibited dome formation. Four of the cell lines, PEO1, PEO4, PEO6, and PEO16, have been xenografted into immune-deprived mice and found to be tumorigenic.

Adenocarcinoma↗
PubMed1987

Epidemiological studies of sodium transport and hypertension.

Red blood cell membrane cation transport was measured in five population-based surveys and two randomized, controlled, dietary intervention studies to examine its associations with demographic, biological, and dietary variables in free-living individuals. A total of 508 individuals, 255 with high blood pressure, were studied. Both sexes, blacks and whites, and several age groups were represented. The intervention studies included short-term dietary sodium restriction in normotensive adolescents, and a 4-year multifactorial trial on weight, sodium, and alcohol in hypertensive adults. The findings from these surveys and intervention studies are summarized in this report. Sodium-stimulated lithium countertransport was significantly related to diastolic blood pressure in white adults (r = 0.28, p less than 0.001), and to systolic blood pressure in black children (r = 0.50, p less than 0.005) and white adolescents (r = 0.31, p less than 0.05). Lithium countertransport was related to sex and race, but not age. Body mass index had an independent relationship with lithium countertransport in some age groups. Lithium countertransport was lower in normotensive adults than in both younger and older hypertensive adults. Lithium countertransport did not differ significantly between subjects with hypertension treated with antihypertensive medications and those with untreated hypertension. Short-term dietary sodium restriction did not influence lithium countertransport in normotensive adolescents. Long-term dietary intervention was associated with low lithium countertransport in hypertensive adults able to maintain blood pressure control without medication. These findings indicate that lithium countertransport is related to blood pressure and hypertension among free-living individuals.

Adolescent↗
PubMed1986

The role of weight in the positive association between age and blood pressure.

This study used cross-sectional data for 19,704 white men and 13,895 white women from the Chicago Heart Association Detection Project in Industry (November 1967 to January 1973) to investigate whether weight explains the association between age and blood pressure, and in particular, whether age is associated with blood pressure and hypertension in the absence of overweight. The relations among age, relative weight, and blood pressure were examined through assessment of mean blood pressure levels and prevalence of hypertension in 25 subgroups stratified by age (18-24, 25-34, 35-44, 45-54, and 55-64 years) and by relative weight (less than 100%, 100-109%, 110-119%, 120-134%, and greater than or equal to 135%). For all five relative weight groups, for both men and women, mean diastolic blood pressure was higher at successive ages. This phenomenon was also seen for systolic blood pressure after ages 35-44 years for men, and after ages 25-34 years for women. On the other hand, the higher the relative weight was, the higher the blood pressure was. Regression analysis demonstrated that the observed relation between age and blood pressure was consistent for all five relative weight groups, including those at desirable weight. These data indicate that for US subjects, age and blood pressure are generally associated in the absence of overweight.

Adolescent↗
PubMed1985

The production and assessment of monoclonal antibodies to cortisol.

In an extensive series of experiments, Balb/C mice and Lou rats were immunised with 3-O-(carboxymethyl)oximinocortisol conjugated to bovine serum albumin. The spleen cells from selected animals were fused with cells from mouse or rat plasmacytoma lines. Out of many hundreds of hybridomas screened, more than seventy produced antibody that bound 125I-labeled cortisol. These cultures were investigated further for stability of antibody production, affinity for cortisol and cross-reactivity with other steroids. An unexpected but consistent finding was that immunised rats produced antibody which cross-reacted with 11-deoxycortisol to a level greater than 100% and this characteristic was reproduced by rat-rat hybridomas. Strategies designed to improve the chances of generating non-cross-reactive anti-cortisol monoclonal antibodies did not appear to be successful. Nevertheless, several monoclonals were identified with properties that suggest they may be useful for the development of sensitive and specific cortisol assays.

Animals↗
PubMed1985

Kinetics of intravenous and oral pentoxifylline in healthy subjects.

The kinetics of a sustained-release formulation of pentoxifylline were compared with those of a capsule and an intravenous infusion. Ten healthy subjects received each of the oral pentoxifylline formulations (400 mg) three times a day for 9 days in a random crossover fashion. Pentoxifylline (200 mg) was also given intravenously on a separate day. After intravenous pentoxifylline, plasma levels declined in a biphasic manner, with a terminal t1/2 of 1.63 +/- 0.8 hr. Plasma clearance was 1333 +/- 481 ml/min and the volume of distribution was 168 +/- 82.3 l. Cumulation of pentoxifylline in plasma after repeated dosing was minimal. Plasma levels of the active 5-hydroxylated metabolite were generally higher than those of the parent drug after both routes of administration. Urinary excretion of two acid metabolites after oral and intravenous dosing indicated almost complete absorption of drug-related substances from both of the oral formulations, although bioavailability averaged 20% to 30%.

Administration, Oral↗
PubMed1984

Disposition of cefotaxime in rat, dog and man.

The excretory pathway for the elimination of 14C-cefotaxime (14C-HR 756) was found to be the same for rat, dog and man with elimination into the urine being the most important route, accounting for greater than 80% of the dosed radioactivity. The amounts of unchanged cefotaxime eliminated in the urine ranged from 20-32% in rat and dog to 56% in man. The major metabolite in each species was the microbiologically active desacetyl cefotaxime, which was present in both plasma and urine. Two further metabolites, recently identified as the stereoisomeric forms of the opened beta-lactam ring form of desacetyl cefotaxime lactone were also found in the urine of dog and man.

Adult↗
PubMed1984

Cefotaxime: sites and pathway of metabolic conversion.

This paper examines the metabolism of 14C-cefotaxime (14C-HR 756) in the rat and attempts to identify the metabolic events in this and other species. In rat desacetyl cefotaxime is usually the major excretion product and sole metabolite of cefotaxime. However, when renal elimination of this metabolite is prevented by bilateral nephrectomy, two further metabolites, the stereoisomeric opened beta-lactam ring forms of desacetyl cefotaxime lactone, are also produced. These metabolites are found in the urine of man and dogs dosed with cefotaxime. It is suggested that generation of these metabolites is dependent on formation of the lactone form of the desacetyl metabolite. Evidence is also presented showing that these metabolic conversions occur in the liver.

Animals↗
PubMed1984

The meaning of risk taking behaviour.

This article seeks to share an understanding of that which is important for people who are working and moving with young people at levels other than their own. To 'work the street' is to be present on the street and move with the numbers of young people who, for whatever reason, have chosen to be there between 6 pm and 6 am. These young people express 'risk taking' behaviour.

Adolescent↗