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Biomedical subjects

H H Dayal

Publications and source records attributed to H H Dayal.

At least 19 recordsLinked to original sources
PubMed1999

Polyatomics in zinc isotope ratio analysis of plasma samples by inductively coupled plasma-mass spectrometry and applicability of nonextracted samples for zinc kinetics.

Inductively coupled plasma-mass spectrometry (ICP-MS) is a powerful tool for both quantitative multielement analyses of inorganic elements and measurement of isotope ratios (IRs). The main disadvantage of this technique is the existence of polyatomic isobaric interferences at some key masses. Zinc has been investigated for such potential interferences in serum or plasma. The Zn isotopes, 66Zn and 68Zn, have no apparent interferences, but 32S1602 and 32S2 are isobaric with 64Zn. The possible effects of S and other major components of blood plasma-Na, K, Cl, P, Ca-on Zn IRs were investigated using a series of mineral solutions which simulated human plasma with respect to these elements. The mixture of all mineral elements interfered only with 64Zn (6.66 ng/mL) and 70Zn (8.51 ng/mL). Interferences to 66Zn, 67Zn, and 68Zn were minimal containing 0.90, 0.94, and 0.39 ng/mL, respectively. The copresence of Na or S shifted 35Cl16O2 (atomic mass 67 coming from Cl solution) to 35Cl2 which reduced the contribution to 67Zn. The hypothesis that Zn IRs obtained from plasma at various intervals after the intravenous administration of enriched 67Zn to humans would reflect those obtained after extraction of Zn was therefore tested. To compare the two pretreatment methods, "extraction" versus "nonextraction," specimens were collected from 10 human subjects at intervals of 5 min to 24 h postinjection, and in 4 subjects from 5 min to 9 d postinjection. Two separate aliquots of plasma from each time-point were dried and digested with hydrogen peroxide, and the residue dissolved in nitric acid. One specimen was subjected to zinc extraction using ammonium diethyldithiocarbamate chelate followed by back extraction into nitric acid. The matching aliquot received no further pretreatment. The normalized IRs obtained from 67Zn/66Zn and 67Zn/68Zn in both the "extracted" and "nonextracted" samples agreed well (r2 = 0.976 and r2 = 0.985, respectively) compared to those from other ratios (r2 = 0.838 for 67Zn/64Zn and r2 = 0.747 for 67Zn/70Zn). Considering the minimum possibility of isobaric interferences in plasma samples, 67Zn/68Zn obtained from "nonextracted" samples is sufficient for routine Zn kinetic analysis by ICP-MS.

Argon↗
PubMed1998

Effect of cigarette smoking on major histological types of lung cancer in men.

This study examined the effect of cigarette smoking parameters such as intensity, duration, age at initiation, and quitting on the development of different histological types of lung cancer in men. We used data from a case-control study conducted in Philadelphia between 1985 and 1987. Cases included 482 men with histologically confirmed lung cancer diagnosed in 15 selected hospitals in Philadelphia. Controls were selected from a neighborhood survey of men in Philadelphia conducted concurrently to the case recruitment. Most aspects of smoking were associated with all the major histological types of lung cancer. Number of cigarettes smoked per day was the strongest predictor of risk of developing lung cancer. Early age at initiation of smoking significantly increased the risk of small cell carcinoma (odds ratio = 3.0; 95% CI, 1.1-8.4). Quitting smoking reduced the risk of squamous cell and adenocarcinoma; however, it did not affect the risk of small cell lung cancer. The findings of this study suggest the need for greater emphasis on smoking prevention programs, especially in adolescents.

Adenocarcinoma↗
PubMed1998

Effects of repletion with zinc and other micronutrients on neuropsychologic performance and growth of Chinese children.

The knowledge that zinc is essential for growth and neuropsychologic performance and a report of zinc-responsive stunting in Chinese children prompted this project. This article summarizes findings from a 10-wk, double-blind, controlled trial of zinc repletion in 740 urban, 6-9-y-old first graders from low-income families in Chongqing, Qingdao, and Shanghai, People's Republic of China. Treatments were 20 mg Zn alone (Z), 20 mg Zn with micronutrients (ZM), and micronutrients alone (M). The M mixture was based on National Research Council guidelines. Nutrients that might interfere with zinc retention were excluded or given in lower amounts. Main outcomes were changes in neuropsychologic performance and knee height. Hemoglobin, serum ferritin, plasma and hair zinc, and whole blood and hair lead were also measured. Anemia was not common, and serum ferritin concentrations were usually within the range of normal. Mean baseline plasma zinc concentrations were marginal in children from Chongqing and Qingdao and normal in children from Shanghai. After treatment with ZM or M plasma zinc increased. Hair zinc tended to decrease after all treatments. Mean baseline whole blood lead concentrations were slightly below the limit considered excessive for children by the US Centers for Disease Control and Prevention. Neuropsychologic performance and growth were most improved after treatment with ZM. These findings were consistent with the presence of zinc and other micronutrient deficiencies.

Brain↗
PubMed1997

A preliminary report: effects of zinc and micronutrient repletion on growth and neuropsychological function of urban Chinese children.

OBJECTIVE: Zinc is essential for growth and cognition of experimental animals. Past research found zinc repletion improved growth of stunted Chinese children. Therefore we measured effects of zinc repletion on growth and neuropsychological functions of children. DESIGN: Double-blind randomized controlled treatment trial. SETTING: Elementary schools in low income districts of Chongqing, Qingdao and Shanghai. SUBJECTS: Three hundred-seventy-two 6 to 9 year old first graders. INTERVENTIONS: Treatments were 20 mg zinc, 20 mg zinc with micronutrients, or micronutrients alone. The micronutrient mixture was based on guidelines of the US NAS/NRC. Treatments were assigned to classrooms of 40 or more children each, and administered by teachers 6 days per week for 10 weeks. MEASURES OF OUTCOME: Changes in knee height and neuropsychological functions. RESULTS: Zinc alone had the least effect on growth while zinc with micronutrients had the largest effect; micronutrients alone had an intermediate effect. Zinc-containing treatments improved neuropsychological functions, but micronutrients alone had little effect. CONCLUSIONS: The findings confirm the essentiality of zinc for growth of children, and show, for the first time, the essentiality of zinc for neuropsychological functions of children. In addition, the need for repletion of other potentially limiting nutrients in studies examining the effects of specific nutrients on growth and neuropsychological functions was confirmed.

Analysis of Variance↗
PubMed1996

Race, socioeconomic status and survival in three female cancers.

OBJECTIVES: Although many studies have reported that socioeconomic status (SES) and race affect cancer survival, researchers have not established whether SES and race affect survival independently. The research reported here addresses this question with special attention to cancers affecting large numbers of women in the US. METHODS: The authors analyzed data on survival among patients in the Centralized Cancer Patient Data System (CCPDS) with cancers of the breast (n = 6896), cervix (n = 2209) and uterine corpus (n = 1492). RESULTS: According to Cox proportional hazards models, race predicted survival in all three cancers, while socioeconomic status predicted survival for cancers of the breast and uterine corpus. Interaction effects between race and SES were generally not statistically significant. This study includes larger numbers of observations within specific forms of cancer and covers a broader patient population than most previous investigations. These features promote detectability of SES effects, comparability among disease sites, and generalizability to cancer patients throughout the US. CONCLUSIONS: Findings imply that SES and race affect cancer mortality risk independently of each other, and that the impact of SES and race may vary by malignancy. Survival disadvantages due to race-which may be more pronounced among women than men-should remain a continuing concern.

Adult↗
PubMed1994

Passive smoking in obstructive respiratory disease in an industrialized urban population.

We examined the risk of obstructive respiratory disease associated with tobacco smoke in indoor air, independent of active smoking, ambient air pollution, and some of the other sources of residential indoor air pollution. Data came from a probability sample survey of nine neighborhoods in Philadelphia conducted in 1985-1986, leading to information on approximately 4200 individuals. While for never-smokers the prevalence of obstructive respiratory conditions was proportional to the level of environmental tobacco smoke, this second-hand smoke was not a factor in the frequency of such problems among current smokers. In a series of analyses restricted to never-smokers, each of the 219 index cases of obstructive respiratory disease was matched by age, gender, and neighborhood to three randomly selected controls where matching by neighborhood effectively controlled for ambient air pollution. Both matched and unmatched two-sample analyses showed a statistically significant difference (P = 0.019 and 0.016, respectively) between cases and controls with respect to the level of tobacco smoke in the indoor environment. A conditional logistic regression-matched analysis revealed that heating and cooking as sources of indoor air pollution were not associated with the case/control status. However, the odds ratio for passive smoking at a level of more than one pack per day in the house environment was 1.86 (95% CI, 1.21-2.86). The results show that passive smoking is a significant risk factor for obstructive respiratory disease for never-smokers in an industrialized urban population.

Case-Control Studies↗
PubMed1994

Hazardous chemicals: psychological dimensions of the health sequelae of a community exposure in Texas.

STUDY OBJECTIVE: A chemical spill from an oil refinery exposed the local community to more than 40,000 lb of highly toxic and corrosive hydrofluoric acid. A community based symptom prevalence study found an association between exposure and physical symptoms: the psychological impact of the disaster and its potential effect on the reporting of physical symptoms is examined here. DESIGN: The study used a population based survey design consisting of two phases: phase I, the exposure phase, and, phase II, the symptom prevalence phase. SUBJECTS: In phase I, information indicative of exposure was collected on 10,811 individuals in a door to door survey of a geographically defined area. In phase II, symptom prevalence information was gathered through in-person interviews with 2509 subjects selected from the phase I census in a sampling scheme that balanced across the exposure categories with regard to age, gender, and predisposition. The refusal rate in both phases was < 5%. MEASUREMENT AND MAIN RESULTS: Stepwise logistic regression analyses were used to assess the relative predictive importance of psychological variables and hydrofluoric acid exposure in explaining the reported physical symptoms two years after the disaster. The findings show a linear relationship between the level of hydrofluoric acid exposure and the degree of psychological stress two years after the accident. High exposure had a long term (more than two years) impact on physical health for some self reported symptoms, even after controlling for the psychological impact. Some physical symptom reports, however, were better explained by psychological status than by exposure to hydrofluoric acid. The physical symptoms for which exposure was the major predictor were those for which the biological plausibility of a relationship with hydrofluoric acid exposure was direct. CONCLUSIONS: Measures of psychological status should be included in symptom studies of health sequelae to man-made disasters so that the physical effects of exposure can be more accurately assessed.

Adolescent↗
PubMed1992

A community-based epidemiologic study of health sequelae of exposure to hydrofluoric acid.

An accident at an oil refinery in Texas City, Texas, released around 40,000 lb of hydrogen fluoride, exposing the community to the highly toxic and corrosive substance. A population-based epidemiologic study was conducted to evaluate the impact of the accident on the health of the community. Exposure assessment was done using a multipronged approach through a door-to-door survey of 10,811 individuals. A symptom survey resulting in 1994 completed interviews was conducted with a stratified random sample selected from the exposure study database. The sampling was balanced with respect to age, gender, and predisposition across the three ordinal exposure categories. The results show a strong dose relationship (P < 10(-4)) between the exposure and symptoms reported following the accident and 2 years later, most notably breathing and eye symptoms. However, substantial improvement in health was reported over the 2-year period regardless of the level of exposure. Problems of recall bias and behavioral sensitization are considered and it is recognized that the study may have overestimated the effect. It is also recognized that the study may not have completely unraveled the relative importance of exposure and host response in health outcome, since the two were probably conflated in the exposure measure. Nevertheless, the independence of predisposition and reported level of exposure, the magnitude of effect and its consistency, the unmistakable dose response, the large sample size, and the mutual corroboration of various findings make it difficult to dismiss the interpretation that the hydrofluoric acid exposure indeed caused health problems in the community that continued for at least 2 years after the accident.

Accidents, Occupational↗
PubMed1985

Race, socioeconomic status, and other prognostic factors for survival from prostate cancer.

Survival data on prostate cancer patients from 11 Comprehensive Cancer Centers contributing data to the Centralized Cancer Patient Data System were analyzed to examine the contribution of various factors to the probability of survival from prostate carcinoma. Application of a number of exclusion criteria resulted in a series of 2,513 patients (1,032 blacks and 1,481 Caucasians) for whom complete data on variables of interest were available. The stage of disease at diagnosis was a major determinant of survival. The proportion of blacks presenting the disease in advanced stage was substantially higher than that of Caucasians--a difference which was maintained within each socio-economic status (SES) category. Caucasian patients had a better prognosis than blacks for each disease stage. A dose-response relationship between SES and survival prognosis was observed and this relationship persisted for each stage of the disease. Although both race and SES turned out to be significant in regression models in which one or the other was considered, the model including both race and SES showed only SES to be a significant factor. Hence it can be hypothesized that the racial difference in the survival prognosis for prostate cancer is, to a large extent due to the differences in the distribution of SES in the two races.

Adult↗
PubMed1983

Research in cancer patient education and compliance.

A study design has been presented which has the advantage of combining the research questions of education program evaluation and patient compliance. While it would be possible to evaluate education programs in other ways (e.g., using a sample of all program participants rather than a sample of all patients for whom a regimen was recommended), such an alternative design would not assess the potentially significant proportion of noncompliance which might occur when the regimen recommendation is made. It is the specification of inception cohorts as the study population that allows the accrual of more complete compliance data for the regimen as well as evaluation data for the education program. Given the recognized need for data on the compliance of cancer patients, the added cost of specifying inception cohorts for education program evaluations seems small. The proposed research design has the potential to contribute to cancer control programs: 1. a careful evaluation of new education programs for patients; 2. modifications of education programs based on feedback from professionals and patients during the initial implementation; 3. needed data on cancer patient compliance with extended detection and treatment regimens; and 4. increased understanding of the process of patient compliance, including identification of key variables in the health belief model which account for compliance among cancer patients.

Evaluation Studies as Topic↗
PubMed1982

Race and socio-economic status in survival from breast cancer.

The survival data on 515 white and 388 black female breast cancer patients seen at the Medial College of Virginia between 1968 and 1977 were analyzed to study the effect of age, stage and race on survival prognosis. For a subset of the data representing patients from the city of Richmond (117 white and 206 black), socio-economic status (SES) information was generated on the basis of six predictors of SES and, in addition, the role of social class was studied. Each of these factors has a significant association with survival time. In particular, the probability of surviving a given length of time after diagnosis is ordered according to the socio-economic level and the statistical test for dose response show a highly significant directional relationship. Age and stage do not explain the difference in survival between the two races. Race and SES are highly associated; a higher proportion of blacks than whites come from the lower end of the socio-economic scale. Moreover, the racial difference in survival becomes insignificant when it is adjusted for the distribution of socio-economic levels. This suggests that the observed difference in breast cancer survival between blacks and whites is, to a large extent, due to the difference between the two races with respect to the distribution of socio-economic status.

Adult↗
PubMed1982

Factors associated with racial differences in survival for prostatic carcinoma.

The survival data on 99 white and 292 black patients with a carcinoma of the prostate from the city of Richmond seem at the Medical College of Virginia between 1968 and 1977 were analyzed. Black patients with prostatic cancer have significantly poorer survival prognosis than whites. The distribution of stage at diagnosis is unfavorable to blacks in comparison to whites. Also, blacks present with less differentiated tumors. Degree of differentiation and clinical stage are highly associated and both are important predictors of survival. The prognosis differential between the two races does not seem to be due to difference in the biology of the disease; it is more likely due to the 'environment', defined in the broadest sense. Socio-economic status is associated with race and explains the racial difference in survival.

Age Factors↗