PubMed Health⌕ Search

Biomedical subjects

C R Mehta

Publications and source records attributed to C R Mehta.

8 recordsLinked to original sources
PubMed1988

Exact inference for matched case-control studies.

In an epidemiological study with a small sample size or a sparse data structure, the use of an asymptotic method of analysis may not be appropriate. In this paper we present an alternative method of analyzing data for case-control studies with a matched design that does not rely on large-sample assumptions. A recursive algorithm to compute the exact distribution of the conditional sufficient statistics of the parameters of the logistic model for such a design is given. This distribution can be used to perform exact inference on model parameters, the methodology of which is outlined. To illustrate the exact method, and compare it with the conventional asymptotic method, analyses of data from two case-control studies are also presented.

Algorithms↗
PubMed1986

Anxiety levels in patients randomized to adjuvant therapy versus observation for early breast cancer.

We studied anxiety levels in 68 patients who had been randomized to adjuvant chemotherapy v observation on two Eastern Cooperative Oncology Group (ECOG) protocols. All subjects were women who had undergone total or modified radical mastectomy for breast cancer. Immediately before breast protocol randomization and again 3, 6, and 12 months later, patients completed two self-report measures: the State-Trait Anxiety Inventory and the SCL-90. There were no consistent trends in anxiety levels over time. At each test point, patients under observation displayed higher anxiety scores than did patients receiving adjuvant therapy, but these differences failed to attain statistical significance. Power calculations indicate that these results rule out the possibility of major differences in anxiety levels among patients randomized to observation v adjuvant therapy, but a larger patient sample is required before a definitive statement can be made about smaller differences.

Aged↗
PubMed1986

An intervention study of tobacco chewing and smoking habits for primary prevention of oral cancer among 12,212 Indian villagers.

In a house-to-house screening survey, 12,212 tobacco chewers and smokers were selected from the rural population in the Ernakulam district, Kerala state, India. These individuals were interviewed for their tobacco habits and examined for the presence of oral cancer and precancerous lesions, first in a baseline survey, and then annually, over a five-year period. They were educated using personal and mass media communication to give up their tobacco habits. The control group was provided from the results of the first five years of a 10-year follow-up study conducted earlier by the authors in the same area with the same methodology but on different individuals without any educational intervention. The stoppage of the tobacco habit was substantially higher in the intervention group (9.4%) compared to the control group (3.2%). A logistic regression analysis showed that the behavioural intervention was helpful to all categories of individuals, however, the effect was different for different categories: intervention was more helpful to men, chewers, and those with a long duration of the habit. These individuals rarely quit their habit without intervention.

Adolescent↗
PubMed1979

MACC chemotherapy for adenocarcinoma and epidermoid carcinoma of the lung: low response rate in a Cooperative Group Study. Eastern Cooperative Oncology Group.

The MACC (methotrexate, adriamycin, cyclophosphamide, CCNU) regimen was administered to 43 patients with advanced epidermoid and adenocarcinoma of the lung. Only 5 patients (12%), all of whom were ambulatory responded with partial remissions. Median time to progression for the 5 responders was 20 weeks from start of treatment. Median survival was 15.5 weeks for patients with epidermoid cancer and 14.4 weeks for those with adenocarcinoma. Hematologic toxicity was severe, with 2 treatment-related deaths during profound myelosuppression. White blood counts below 2000/microliter were reported in 47%, and below 1,000/microliter in 26%. Since the activity of this regimen, given as it was in full doses, is not superior to that achieved with standard doses of single agents which are less toxic, further employment of the MACC regimen is not recommended, either for advanced disease or as a surgical adjuvant.

Adenocarcinoma↗
PubMed1979

Cancer mortality among beekeepers.

Carcinogenic effects of bee venom were evaluated in a mortality study of 580 occupationally exposed beekeepers. The subjects were identified through obituary notices published between 1949 and 1978 in three journals of the U.S. beekeeping industry. Death certificates of beekeepers were examined for causes of mortality, and proportionate mortality ratios were compared with those for the general U.S. population. Beekeepers had a slightly lower than expected fraction of deaths from cancer. The deficit of lung cancers in male beekeepers was significant (p less than 0.05) and may indicate that fewer beekeepers were cigarette smokers. The frequencies of other cancers did not differ significantly from expectation. Non-Hodgkin lymphoma developed in four persons, and was expected in two. Mortality from diseases other than cancer showed no unusual patterns. At least two persons died from accidents directly related to the care of beehives. Analysis of a subgroup of 377 males with major roles in the beekeeping industry showed no substantial differences in distribution of causes of death. This study of beekeepers reveals neither adverse nor beneficial effects of intense exposure to bee stings.

Bee Venoms↗
PubMed1979

The genetics of PLT response. II. HLA-DRw is a major PLT-stimulating determinant.

PLT response is restricted by the HLA-D region. The present study was undertaken to help define the role of HLA-DRw in PLT restimulation. Haplotype-primed intrafamily PLT cells were made against specificities HLA-DRw1, HLA-DRw3, and HLA-DRw7; each PLT was then restimulated with cells from a 35-member unrelated panel. Restimulation values for each PLT were subjected to bimodal clustering analysis. In addition, blocking experiments were performed with other intrafamily and homozygous typing cell PLT after preincubation with B cell alloantisera. The results show a high correlation (0.881 less than or equal to r less than or equal to 1.00) between the HLA-DRw specificity of the priming haplotype and the HLA-DRw specificity of unrelated panel cells that restimulate in PLT. When stimulating cells were absorbed with the corresponding DRw alloantisera or p29,34 heteroantiserum (against B cell specific antigens), PLT restimulation was significantly blocked. However, the PLT cells treated with antisera showed no effect. The results strongly suggest that HLA-DRw is the principal PLT-stimulating determinant.

Binding, Competitive↗