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Biomedical subjects

M Howard

Publications and source records attributed to M Howard.

At least 235 records · Page 13Linked to original sources
PubMed1974

A rapid, simple assay for digoxin.

An extremely rapid radioimmunoassay for digoxin is described which is precise over the range of concentrations required to determine whether, or not, a patient has digoxin toxicity. The assay is based on the use of (125)-iodine-labelled digoxin and of a gel equilibration technique for the separation of antibody-bound and free digoxin. The results obtained compare closely with those by a conventional radioimmunoassay and the technique is sufficiently simple to enable its performance by relatively inexperienced laboratory staff.

Binding Sites, Antibody↗
PubMed1972

Myocardial and skeletal muscle concentrations of digoxin in patients on long-term therapy.

The digoxin content was measured in samples of left ventricular papillary muscle, skeletal muscle, and plasma obtained during mitral valve replacement from eight patients on maintenance treatment with the drug. The content in papillary muscle ranged from 15.5 to 132 ng/g (mean 77.7) and in skeletal muscle from 7.5 to 23 ng/g (mean 11.3). The ratio of myocardial digoxin concentration to plasma concentration varied between patients from 39:1 to 155:1. No simple relationship exists between plasma levels of digoxin and its concentration in the heart muscle, but total myocardial concentration may not accurately reflect therapeutic activity.

Adult↗
PubMed1971

Plasma concentrations of digoxin after oral administration in the fasting and postprandial ste.

After the oral administration of 0.5 mg of digoxin in tablet form to fasting subjects peak plasma levels were reached in 30 to 60 minutes. Levels then fell to reach a plateau at six to eight hours. When the same dose was given after food the peak plasma concentrations were significantly lower, but the concentrations reached in samples obtained from two to eight hours after the dose did not differ appreciably from corresponding samples obtained in the fasting experiments.In a four-week cross-over study of 21 patients on maintenance therapy, digoxin taken regularly in the fasting state produced plasma concentrations similar to those obtained when the drug was taken after meals.The rapid appearance of digoxin in the blood suggests that the oral route of administration is adequate for most patients who require rapid digitalization, and the timing of maintenance dosage in relation to meals is unimportant.

Administration, Oral↗
PubMed1968

Rapid, sensitive assay for staphylococcal enterotoxin and a comparison of serological methods.

Reversed passive hemagglutination was used to assay enterotoxin in culture filtrates and in food samples. With cells tanned and then sensitized with antitoxin globulin and preserved with either formaldehyde or pyruvic aldehyde, as little as 0.0007 mug of enterotoxin was detectable. The results of hemagglutination tests compared well with those obtained by quantitative precipitin tests or by immunodiffusion, but hemagglutination was 50 to 100 times more sensitive than the immunodiffusion technique. In addition, results of the hemagglutination test were available within a few hours, and neither elimination of interfering proteins from food extracts nor concentration of the sample, both of which are necessary for immunodiffusion, was required for this procedure.

Antitoxins↗
PubMedDate not supplied

Practice what we preach? HIV knowledge, beliefs, and behaviors of adolescents and adolescent peer educators.

The purpose of this article is to (a) describe the knowledge, beliefs, and sexual behaviors of urban adolescents and adolescent peer educators, and (b) identify elements needed to design effective HIV/AIDS prevention programs for out-of-school youth. Thirty-three predominantly African American adolescents (female = 14; male = 19) between the ages of 14 and 24 in a large urban city including adolescent (n = 18) and adolescent peer educators (n = 15) participated. Paper-and-pencil questionnaire and focus-group interviewing methods were used. Adolescents and adolescent peer educators had a moderately high level of HIV knowledge, confidence in their ability to use condoms, and beliefs that condom use would not decrease sexual pleasure or imply infidelity. Both groups reported low perceptions of susceptibility of HIV infection. Engagement in sexual risk behavior was low, but was significantly higher among males. Although adolescent male peer educators engaged in a higher frequency of risk behaviors over time, they had a lower frequency of sexual risk behaviors in the past 2 months compared with male adolescents. Study findings showed that HIV prevention interventions need to include information about specific risk behaviors, such as using condoms for oral sex, and cleaning drug paraphernalia. Community-based and church programs, visible HIV prevention messages, specifically those aimed at increasing perceptions of HIV risk, and the development of condom-use skills were identified by adolescents and adolescent peer educators as relevant approaches to reduce HIV infection among this population.

Adolescent↗
PubMedDate not supplied

Mothers' decision-making processes regarding health care for their children.

This research study explored mothers' decision-making processes regarding health care for their children. Identifying how decisions are made by mothers about health care for their children will assist health care professionals to be appropriate advocates for mothers, to improve quality of life, and to contain costs of health care for children. A sample of 114 rural mothers (51 with one child, 63 with more than one child) completed questionnaires identifying demographics, social support, client and professional interaction elements, self-determinism, competence in problem-solving skills, and relationships to responses to health care scenarios. Qualitative data were also gathered by structured in-depth interviews of 7 subjects. ANOVA, correlations, and factor analysis were completed to analyze data. Most of the mothers' decisions were based on the perceived degree of seriousness, mother's degree of fear of the child's condition, attitude of the health care provider, previous experience with the situation, and social support for the mother. There were no significant differences in decision-making processes by first time mothers and by mothers with more than one child. Implications include teaching mothers assessment skills to identify serious versus nonserious situations and to utilize other social supports.

Adolescent↗
PubMedDate not supplied

The hippocampus and delayed recall: bigger is not necessarily better?

Healthy young female participants were tested on a measure of delayed verbal recall and then received volumetric Magnetic Resonance Imaging (MRI) scans. The analysis of the MRI scans focused on the volume of the hippocampus. Left hippocampal volume was negatively associated with the level of delayed verbal recall performance. This relationship was confirmed in further testing. This finding is consistent with a previous report of a similar relationship in healthy elderly individuals, but not in patients with Alzheimer's disease, in whom the opposite relationship was observed. An explanation of these findings in terms of impaired neural pruning of the hippocampus is advanced, whereby insufficient pruning of the hippocampus during childhood and adolescence (following adequate growth) may lead to reduced mnemonic efficiency.

Adult↗
PubMedDate not supplied

Activation systems in contrast idiosyncrasy.

Both animal and human data suggest the possibility that the C1 esterase inhibitor may play an important controlling role in contrast media systemic reactions. This critical controlling protein has a major inhibitory effect on C1, kallikrein, activated factor XII of the intrinsic coagulation system, and on plasmin. In addition, it probably has other inhibitory effects not so well documented. Any circumstance that contributes to a continuing activation of the complement, coagulation, kinin, or fibrinolytic systems may result in partial consumption of the inhibitor and predispose the individual to adverse reactions to contrast challenge.

Anaphylaxis↗
PubMedDate not supplied

Glucocorticoid-induced elevations of C1-esterase inhibitor: a mechanism for protection against lethal dose range contrast challenge in rabbits.

Rabbits pretreated with methylprednisolone acquired significant protection against an intravenous challenge of meglumine iodipamide. In comparison to controls, the pretreated rabbits showed moderate elevations of Factor XII, and rather striking elevations of C1-esterase inhibitor. Treated rabbits also showed significantly less granulocytosis. It is believed that the protective effect can be ascribed to the modulation of acute phase reactants by increased concentrations of C1-esterase inhibitor.

Animals↗