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Biomedical subjects

M A Lewis

Publications and source records attributed to M A Lewis.

At least 235 records · Page 13Linked to original sources
PubMed1984

Peer pressure and risk-taking behaviors in children.

We asked 771 children in grades 5-8 about the dares or challenges they received from other children. A pilot study established categories for classification of the actions proposed ("What did they try to get you to do?"); the techniques utilized ("How did they try to get you to do that?"); and children's responses ("What did you say or do?"). Peer pressure was reported most frequently by 8th grade students. About 50 per cent of the dares encouraged problem behaviors that placed the children (or others) at risk for personal injury, or the potential development of habits hazardous to their health. With increasing age, more occurred in the school environment and fewer involved risk of personal injury. Among 7th and 8th graders, more boys were dared to perform acts of violence, and more girls were challenged to be sexually active.

Adolescent↗
PubMed1984

A randomized trial of A.C.T. (asthma care training) for kids.

A randomized control trial of a curriculum, A.C.T. (Asthma Care Training) for Kids, was conducted. Seventy-six children between the ages of 8 and 12 years, whose asthma required treatment with medications at least 25% of the days per month, were randomly assigned to control and experimental groups. The control group received 4 1/2 hours of lecture presentations on asthma and its management. The experimental groups (consisting of four to seven children and their parents) received five 1-hour sessions comprising "the treatment." Children and their parents were interviewed before the sessions and 3, 6, and 12 months after the completion of the experimental treatment. Use of emergency rooms and hospitals was determined by reviewing the records of these patients (all members of the Los Angeles Kaiser Permanente health care system) for the period of 1 year before and 1 year after the treatment. Results include (1) equivalent increases in knowledge and changes in beliefs in both groups, (2) significant changes in the self-reported compliance behaviors of the experimental group only, and (3) significant reductions in emergency room visits and days of hospitalization among those receiving the experimental treatment, compared with the control group. These changes represent an estimated savings of approximately $180 per child per year for those in the experimental group.

Asthma↗
PubMed1983

Comparative acute toxicities of surfactants to aquatic invertebrates.

Investigations of the toxicity of surfactants to aquatic invertebrates have been limited primarily to determining the effects on a few species. In this study, the 48-hr LC50 values for three surfactants are reported for six species of aquatic invertebrates. The acute toxicities (LC50) for each surfactant (mg/liter) varied 159 to 580 X and were as follows: C11.8LAS (anionic), 1.7 (Dero sp.) to 270 (Asellus sp.); C14-15 alkylethoxylate (nonionic), 1.0 (Dugesia sp.) to 6.8 (Rhabditis sp.); CTAC (cationic), 0.1 (Gammarus sp.) to 58 (Asellus sp.). When compared to previously developed data, Daphnia magna was typically found to be the most sensitive of all species tested, including fish, to the surfactants.

Animals↗
PubMed1983

A multiple extraction--centrifugation method for the recovery of viruses from waste water treatment plant effluents and sludges.

Absorption of 14C-labelled poliovirus-2 to sedimentable solids of primary sludge samples collected from a secondary treatment facility during a 6-month period averaged 94%; for anaerobically digested sludge, 99%. The extent of virus adsorption was influenced by the amount of solids. Maximal adsorption occurred at or above 0.5% solids with sludge diluted with deionized water and above 1.5% solids when diluted with the respective particle-free sludge supernatants. A Tris-HCl buffer containing NaCl, glycerol, and serum was found to efficiently elute poliovirus-2 from primary sludge solids. By means of re-extraction and concentration by centrifugation (the TEC procedure), the average recoveries of poliovirus-2 were 92-94% based upon either infectivity or radioactivity analyses. Similarly, recoveries were 90-92% for poliovirus-2 in digested sludge. Maximum elution was dependent upon all four TEC buffer components and the restriction of solids to less than or equal to 1.0%. The procedure was found to be more efficient than glycine-NaOH and Freon procedures or elution with beef embryo extract. As adapted for effluents the procedure increased the yield and improved the consistency of virus recovery. The arithmetic mean titers and obtained during a monitoring study for primary and digested sludge were 4.2 X 10(5) and 5.1 X 10(3) plaque-forming units (pfu)/L; for primary, secondary, and final effluents 2.3 X 10(5), 4.7 X 10(3), and 4.7 X 10(2) pfu/L, respectively.

Centrifugation↗
PubMed1980

Child-initiated health care.

For us, the 1970s have meant involvement in a variety of settings and a slow but progressive exploration of the extent to which children can and should be involved actively in the processes of their own health care. All of the evidence suggests that children are far more competent than adults believe them to be and, given the opportunity, they might grow up to do that which we as adults do very poorly - take care of ourselves. While studies of health-related beliefs and behaviors of children were relatively uncommon prior to the 1970s, we predict that the 1980s will see a flurry of activity in this area as it becomes apparent that the attitudes and behaviors which are the principle determinants of health status in adulthood are formed very early, and that these can be influenced for the better by those who care about the health of children.

Child Behavior↗
PubMed1980

Managing nurse practitioners in ambulatory care: what are the issues?

Current emphasis on cost containment of health care services has spurred interest in the expansion of primary care in ambulatory care centers. While nurse practitioners can contribute significantly to ambulatory care, their effectiveness depends on the climate in which they perform--nursing administrators play a key role in creating that climate. This article discusses the issues nursing administrators face in the selection, management, evaluation, and reimbursement of nursing practitioners.

Ambulatory Care↗
PubMed1979

Ornithine decarboxylase activity and DNA synthesis after treatment of cells in culture with 12-O-tetradecanoylphorbol-13-acetate.

The ability of the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) to induce the enzyme ornithine decarboxylase (ODC) and to stimulate DNA synthesis was studied in four different cell types in vitro. The effects of this agent on each cell type were different: (a) in hamster embryo cells, TPA induced ODC but had no effect on DNA synthesis; (b) TPA induced ODC and stimulated DNA synthesis in BALB/c 3T3 mouse cells; (c) it did not induce ODC in human fibroblasts but did stimulate DNA synthesis; and (d) it induced neither ODC nor DNA synthesis in rat embryo fibroblasts. In contrast to the effects of TPA, ODC was induced and DNA synthesis was stimulated in all cell types by fresh serum-containing medium. Treatment of the cells with a combination of fresh medium and TPA resulted in an approximate summation of the effects of treatment with each agent alone. These results emphasize the differences in the responses of various cells to TPA. They also show that in some cells, at least, the induction of ODC and stimulation of DNA synthesis following TPA treatment can be regulated independently.

Animals↗
PubMed1978

Informed consent by children and participation in an influenza vaccine trial.

Two hundred thirteen school children, ages six to nine, were presented the opportunity to participate in an experimental trial of swine influenza vaccine. In non-directive question and answer sessions, all groups of children except one composed only of six year olds elicited all relevant information on the details of the trial and the associated risks and benefits. Forty-six per cent of the subjects declined to participate. Letters requiring informed consent of the parents were sent to the homes of the others. Almost 15 per cent of these parents agreed to their children's participation. In this setting, children initiate their own visits to the school nurse practitioner. A significant association was found between volunteering for the study and higher use of services (but not for medical reasons). Younger children and boys, regardless of their patterns of use, were less inclined to volunteer for the experiment.

Age Factors↗
PubMed1978

Objective assessment of prior air traffic control-related experience through the use of an occupational knowledge test.

The Occupational Knowledge Test (OKT) 101-B was administered to 784 air traffic control trainees who entered the FAA Academy's 16-week training course in 1976. All trainees completed the nonradar laboratory portion of the training and, in addition, completed a preemployment questionnaire. Based on responses to the questionnaire, the trainees were assigned to one of three experience groups, corresponding to groups given credit for experience using Civil Service Commission (CSC) selection procedures. It was found that the OKT was highly correlated with experience (r = 0.64) and, in addition, had a higher correlation with successful completion of the nonradar lab than did experience (r = 0.25 vs. 0.12). It was determined that use of an OKT score of 75 or above to assign extra credit would result in a failure rate of 3.1% for those receiving credit, while use of the current experience scale would result in a failure rate of 7.6% for those receiving extra credit on the CSC selection battery. The results held up for a cross-validation sample of 432 trainees who entered the Academy during 1977. Based on the results, it is recommended that an OKT score of 75 or above be used to assign extra credit for experience in the selection of air traffic controllers.

Aviation↗
PubMed1977

The potential impact of sexual equality on health.

There are major differences between the sexes in morbidity and mortality rates. At all ages males have higher death rates and are more frequently afflicted with the chronic diseases associated with considerable reductions in longevity. Trend data indicate that males have become relatively more disadvantaged during a period characterized by major advances in medicine and increased access to care. In contrast, rates of disability and use of services are higher among females. There is some evidence that these differences are associated more with behavioral than with biologic factors. Certain shifts in age-specific mortality rates reflect sex-role-related changes in behavior--e.g., increased consumption of tobacco by women and a reversal in sex mortality ratio for cancer of the lung. Changes in sex roles may affect directly, or indirectly through family dynamics, the health status of both sexes.

Acute Disease↗