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Biomedical subjects

C A Howard

Publications and source records attributed to C A Howard.

32 records · Page 2Linked to original sources
PubMed1988

Spirometric prediction equations for Hispanic children and adults in New Mexico.

We conducted a population-based survey of respiratory diseases and lung function in a New Mexico Hispanic community, and developed spirometric prediction equations based on data from 576 children and adults. Spirometric test procedures were followed as recommended by the American Thoracic Society. For children 6 through 18 yr of age, we used a logarithmic model to predict spirometric parameters. We used simple linear regression for adults 25 through 80 yr of age. On the basis of exploratory analyses, we excluded adult subjects who were obese, defined as a body mass index of 30 kg/m2 or greater. This report describes these regressions. We did not perform regression analysis for those subjects between 19 and 24 yr of age because of small numbers and the inappropriateness of grouping these subjects with older adults for regression analysis. As an alternative to a regression equation for this age group specifically, we propose linear interpolation between values obtained using prediction equations developed for children and for adults. Finally, we compared the percent predicted values obtained from our internal prediction equations with equations from other populations of white children and adults. In general, the comparison equations underestimated the percent predicted values in our population.

Adolescent↗
PubMed1987

Salivary cotinine levels and involuntary tobacco smoke exposure in children and adults in New Mexico.

We conducted a population-based household survey of respiratory disease in 2,029 children and adults and measured salivary cotinine levels by radioimmunoassay in 1,360 nonsmokers and ex-smokers. At all ages median and mean cotinine levels among nonsmokers and ex-smokers increased with the number of smokers in the home. The prevalence of a detectable level of cotinine was about 35% for those not living with a cigarette smoker and was greater with the number of cigarettes smoked by household members. In a multiple logistic regression model, the major determinants of a detectable level of cotinine in children were mother's smoking (odds ratio (OR) = 3.2), father's smoking (OR = 2.1), and smoking of other household members (OR = 4.0). Among adults, the effects of spouse's smoking were smaller with OR = 1.3 and 1.4 for husband's and wife's smoking, respectively. We conclude that in the general population cotinine can be frequently detected in the saliva of nonsmokers, even among those not living with a smoker.

Adolescent↗
PubMed1986

Identification of DNA repair and damage induced proteins from Neurospora crassa.

The response of Neurospora crassa to DNA damage induced by UV irradiation has been studied using two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). Whole cell extracts of irradiated and untreated cultures were compared. Five polypeptides that show changes in response to DNA damage have been identified. Several mutagen sensitive strains of Neurospora were also tested for polypeptide changes on 2-D PAGE. Profiles of whole cell extracts of these mutant strains were compared to wild type. Two changes were observed in the meiotic mutant, mei-3 and one change was detected in the excision repair mutant, upr-1. Two changes were also detected in the allelic mutants, uvs-3 and nuh-4. Profiles of uvs-3 and nuh-4 revealed one polypeptide that was missing and another polypeptide which appeared to shift to a more basic position. This same shift was detected in wild type after induction by UV irradiation or heat shock.

DNA Repair↗
PubMed1984

The human lymphocyte in vitro cytogenetic assay: positive and negative control observations on approximately 30000 cells.

Data are presented from the cytogenetic analysis of the peripheral lymphocytes from 94 male and 15 female donors. However, a much smaller number of regular donors were selected for regular use. A total of 28674 cells were analysed and these acted as negative and positive controls in the in vitro human lymphocyte tests accumulated in this laboratory over a 6-year period. The significant observations were:. (1) in untreated and solvent control treated cultures (a) no chromosomal interchanges were observed in 21570 cells; (b) the incidence of dicentrics was less than 1 per 10000 cells; (c) other types of aberrations were seen with an increased frequency, chromosomal gaps being the most variable. (2) The reference clastogens mitomycin C and cyclophosphamide produced high and remarkably consistent yields of all types of aberrations. It is concluded that when screening compounds in vitro for new genotoxins, aberrations such as chromosomal interchanges and dicentrics (due to their rarity in negative control cultures) should be accorded greater significance than the several other types of aberrations routinely seen. These conclusions emphasize the value of maintaining and updating adequate historical control records.

Antibiotics, Antineoplastic↗
PubMed1983

Survey research in New Mexico Hispanics: some methodological issues.

A prevalence survey of respiratory diseases was conducted in Albuquerque, New Mexico, with the objective of explaining differing patterns of respiratory disease epidemiology in Hispanic and non-Hispanic whites (Anglos). The study population was selected at random from the 1978 R.L. Polk & Co. Directory. This paper focuses on methodological issues raised during the conduct of the study: response rates, potential language barriers and bias, and identification of Hispanics by surnames. Mail, telephone, and personal interview approaches were used to obtain adequate response rates, which ranged from 60% in Hispanic males to 78% in Anglo females; 22% of Hispanic males refused interview. Fewer Hispanics returned mailed questionnaires than responded to telephone interviewing. Spanish language was increasingly preferred as the respondent's age increased. Two methods of ethnic identification by surname (1980 Census List of Spanish Surnames and a computer program, GUESS (Generally Useful Ethnic Search System) were compared to the self-reported ethnicity of respondents. The GUESS Program was more sensitive than the census list, but the census list was more specific. The combination of both methods produced a 90% sensitivity and 97% specificity in males. Intermarriage reduced the accuracy in females.

Adult↗
PubMed1982

Malignant melanoma of the skin in New Mexico 1969-1977.

We assessed the occurrence of malignant melanoma of the skin in New Mexico from 1969-1977. Incidence data, collected by the New Mexico Tumor Registry, were supplemented with mortality data supplied by the State Bureau of Vital Statistics. These data were analyzed for variation by site, sex, and ethnic group. Malignant melanoma occurrence varied with ethnicity. Incidence rates for non-Hispanic whites (Anglos) exceeded comparison US rates, and were approximately six times higher than for other ethnic groups. Annual incidence rates for Hispanics, American Indians, and blacks of both sexes ranged from 0.0-1.8 cases per 100,000. As anticipated from other studies, the lower extremities were the most common site in Anglo women, and the trunk was the most common site in Anglo men. In contrast, the trunk was the most common site for both Hispanic men and women. A statistically significant trend of increasing incidence was demonstrated only for the Anglo women. Mortality rates varied widely during the study period and did not correlate with incidence rates.

Adolescent↗
PubMed1982

Respiratory disease in a New Mexico population sample of Hispanic and non-Hispanic whites.

To characterize the epidemiologic features of respiratory diseases among Hispanics, we conducted a prevalence survey in Bernalillo County, New Mexico. The ATS-DLD-78 respiratory symptoms questionnaire was completed by 633 Hispanics and 1,038 Anglos (non-Hispanic whites) with an overall response rate of 72%. The prevalence of major respiratory diseases differed between the groups. Physician-confirmed chronic bronchitis or emphysema, and asthma were reported less often by Hispanics. Although patterns of cigarette usage (current, previous, never) were similar, current and cumulative cigarette consumption was significantly lower in Hispanics. Most differences in symptom frequency and the lower Hispanic prevalence of chronic bronchitis or emphysema were attributable to lower cigarette consumption by Hispanics. However, the prevalence of asthma remained significantly lower among Hispanics after controlling for cigarette smoking. These results documented differences in the prevalence of respiratory disease between the Hispanics and Anglos, which were partially explained by the distributions of known risk factors.

Adult↗
PubMed1981

Lithium carbonate and granulocyte production: dose optimization.

To determine the optimal dose of lithium for inducing granulocytosis, the authors administered lithium carbonate to normal volunteers at five dose levels. The authors performed assessments of circulating and marginated blood pools of granulocytes and of marrow reserve granulocytes to confirm that the early granulocytosis following lithium administration is due to increased granulocyte production rather than redistribution. At 300 mg/day and 600 mg/day, lithium had no significant effect on granulocyte production. Doses of 900, 1200, and 1500 mg/day, corresponding to lithium levels of 0.55 to 1.50 mEq/liter, were associated with increased granulocyte production. Within this therapeutic range, no correlation between lithium level and granulocyte production was demonstrated. This study suggests that any lithium dose which achieves a lithium level of greater than 0.55 mEq/liter, i.e., doses greater than or equal to 900 mg/day, is adequate to induce granulocytosis. While lithium did not increase platelet production, doses of 900 mg/day to 1500 mg/day were associated with decreased bleeding times.

Adult↗
PubMed1981

Clinical assessment of cimetidine myelotoxicity.

After case reports of alleged cimetidine-induced neutropenia, we investigated the possibility that cimetidine might produce occult bone marrow injury by a mechanism other than idiosyncratic hypersensitivity. We performed hydrocortisone challenge tests to assess the bone marrow granulocyte reserves before, during, and after cimetidine administration. No decrease in marrow granulocyte reserves was associated with the administration of cimetidine. When cimetidine and lithium were given to volunteers, the granulocytosis normally associated with lithium was not diminished. Although a general myelosuppressive effect of cimetidine has been postulated by others, we found no evidence of such a phenomenon in this study. Idiosyncratic drug sensitivity is probably the mechanism of cimetidine-induced neutropenia.

Agranulocytosis↗
PubMed1979

Augmentation of clinical services in rural areas by health sciences students.

Over a five-year period 230 senior-level students in medicine, nursing, and pharmacy served in clinics located throughout five rural communities. Students participated in the development of the clinics and in the organization of services that otherwise would not have been delivered. Community-based preceptors helped integrate the students' learning about community processes. The project provided experiential learning and interdisciplinary interactions that were enthusiastically received by the students. Follow-up surveys suggested that the experience reinforced interest in eventual practice in rural areas and in interdisciplinary settings. The project demonstrated that students were able to provide clinical services which were useful and acceptable to the communities and which were supported by local practitioners.

Ambulatory Care Facilities↗
PubMedDate not supplied

Acculturation, education, and income as determinants of cigarette smoking in New Mexico Hispanics.

Surveys of cigarette smoking among Hispanics in the Southwest have shown a pattern of smoking distinct from that of non-Hispanic whites, but determinants of smoking by Hispanics remain inadequately characterized. We have assessed household income, education, and language preference as predictors of cigarette smoking in 1072 Hispanic adults residing in a community in New Mexico. Cigarette smoking status (never, former, or current smoker) varied strongly with educational attainment, showing the anticipated gradient of increasing smoking as level of education declined. In contrast, cigarette smoking status did not vary in a consistent pattern with reported language preference. A composite measure of socioeconomic status, combining education and household income, predicted continued smoking among ever smokers, whereas language preference had no effect. In males, the age at which subjects started to smoke increased significantly with increasing education; a similar trend in females did not reach statistical significance. Determinants of numbers of cigarettes smoked daily were not identified. The findings suggest that, as in other U.S. populations, Hispanics in the Southwest with lower education and less income should be targeted for smoking prevention and cessation.

Acculturation↗