Comparison of moulting methods for layers: high-zinc diet versus fasting.

The serum biochemical profiles, thyroid hormones, body weights and the production and quality of eggs subsequent to moulting, were compared in laying hens subjected to conventional forced moulting or forced moulting with a diet high in zinc. A total of 200 Dekalb White laying hens in their second production cycle were studied. Blood sampling was conducted in a factorial experimental design (2 × 3) with two methods of moulting (fasting or zinc) and three sampling periods (pre-moult, moult and subsequent peak). Total egg protein content, including globulins, was greater with the zinc diet, whereas egg weight and albumen percentage were greater after fasting. The zinc method resulted in an increased shell thickness and calcium percentage but lower percentage of phosphorus. During the moulting period, the hens in the zinc group had heavier mean body weights. It was concluded that moulting with a high-zinc diet could replace fasting, without negative effects on body weight, biochemical variables or subsequent egg quality and production. The zinc method was also better for the birds' welfare.

Hospital visitors as controls in case-control studies.

OBJECTIVE: Selecting controls is one of the most difficult tasks in the design of case-control studies. Hospital controls may be inadequate and random controls drawn from the base population may be unavailable. The aim was to assess the use of hospital visitors as controls in a case-control study on the association of organochlorinated compounds and other risk factors for breast cancer conducted in the main hospital of the "Instituto Nacional de Câncer" - INCA (National Cancer Institute) in Rio de Janeiro (Brazil). METHODS: The study included 177 incident cases and 377 controls recruited among female visitors. Three different models of control group composition were compared: Model 1, with all selected visitors; Model 2, excluding women visiting relatives with breast cancer; and Model 3, excluding all women visiting relatives with any type of cancer. Odds ratios (OR) and 95% confidence intervals were calculated to test the associations. RESULTS: Age-adjusted OR for breast cancer associated with risk factors other than family history of cancer, except smoking and breast size, were similar in the three models. Regarding family history of all cancers, except for breast cancer, there was a decreased risk in Models 1 and 2, while in Model 3 there was an increased risk, but not statistically significant. Family history of breast cancer was a risk factor in Models 2 and 3, but no association was found in Model 1. In multivariate analysis a significant risk of breast cancer was found when there was a family history of breast cancer in Models 2 and 3 but not in Model 1. CONCLUSIONS: These results indicate that while investigating risk factors unrelated to family history of cancer, the use of hospital visitors as controls may be a valid and feasible alternative.

[Epidemiological research trends in chronic diseases]. / Tendências da investigação epidemiológica em doenças crônicas.

Identification of adult risk factors has contributed to a decrease in the occurrence of cardiovascular diseases and some types of cancer, particularly in developed countries. However, the prevailing etiologic model emphasizes risk factors associated with life style and occupational exposures. This emphasis leads to an excessive individualization of risk, weakening the link between epidemiology and public health. This article comments on the opinions of epidemiologists concerning the failures, limitations, and evolution of modern epidemiology that have helped redirect the field's theoretical underpinnings. Alternatives to the current model tend to integrate findings from molecular biology with classic risk factors and early adverse conditions in life, taking into account all these causal influences in hierarchical levels of organization. The author identifies and comments on three important approaches in this evolution: molecular epidemiology, the theory of early life factors, and multilevel models.

Organochlorines and breast cancer: a case-control study in Brazil.

Breast cancer is an important cause of morbidity and mortality in Brazil. Some studies have analyzed the potential role of organochlorine compounds in breast cancer etiology. These chemical compounds have been widely used in agriculture and in vector-control programs in Brazil. A case-control study was carried out in the main cancer hospital of the Instituto Nacional de Câncer in Rio de Janeiro to investigate exposure to organochlorinated pesticides as a risk factor for breast cancer. We investigated 177 cases of invasive breast cancer at the hospital, between May 1995 and July 1996, and 350 controls selected among female visitors at the same hospital. In addition to information obtained from interviews, blood samples were taken, to analyze residual amounts of organochlorine by gas chromatography using an electron capture detector. [1,1-Dichloro-2, 2-bis(p-chlorophenyl)ethylene] (DDE) was determined in sera of 457 women from a total of 493 participants who had serum samples available. Residues of hexachlorobenzene were found in 11 women only. No statistically significant association was found between breast cancer risk and serum level of DDE or history of exposure to pesticides. Serum levels of DDE (ng/ml) were similar in patients (median = 3.1, mean = 5.1) and controls (median = 3.1, mean = 4.8) (p = 0.93). The age-adjusted odds ratio of breast cancer for women in the upper quintile compared with those in the lowest quintile was 0.90 (95% confidence interval 0.47-1.73). When adjusted for other variables, the risk remained not statistically significant (upper quintile odds ratio = 0.79, 95% confidence interval 0.39-1.60). In our hands, exposure to organochlorinated pesticides measured by history or serum analysis was thus not a risk factor for breast cancer.

Detection and analysis of apoptosis in peripheral blood cells from breast cancer patients.

Apoptosis is a well-known specific process of cell death that normally occurs in physiological situations such as tissue or organ development and involution. During tumor growth there is a balance between proliferation and cell death which involves apoptotic mechanisms. In the present study genomic DNAs from 120 breast tumor biopsies were analyzed by agarose gel electrophoresis and none of them presented the fragmentation pattern characteristic of the apoptosis process. However, 33% of the 105 breast cancer patients clearly showed the apoptotic pattern when DNA from blood cells was analyzed. None of the DNAs from healthy volunteer blood cells showed any trace of apoptosis. Since the breast cancer patients were not receiving chemo- or hormone therapy, the possible relationship between blood cortisol levels and the apoptotic pattern found in patient blood cells was investigated. Using a chemoluminescence immunodetection assay, similar cortisol levels were observed in breast cancer patient sera presenting or not apoptotic blood cells and in healthy volunteer sera. Analysis of the clinical data obtained from 60 of these patients showed that patients bearing tumors of smaller size (under 20 mm) were more susceptible to the apoptotic effect in blood cells. According to the Elston grade, it was observed that 7 of 12 patients with grade III tumors (58%) presented apoptotic peripheral blood cells, in contrast to 10 of 48 patients with grade I and grade II tumors. These observations may reflect the immunosuppression characteristic of some breast cancer patients, which may contribute to tumor growth. Therefore, further studies are necessary to elucidate the factor(s) involved in such massive blood cell death.

Detection and analysis of apoptosis in peripheral blood cells from breast cancer patients

Apoptosis is a well-known specific process of cell death that normally occurs in physiological situations such as tissue or organ development and involution. During tumor growth there is a balance between proliferation and cell death which involves apoptotic mechanisms. In the present study genomic DNAs from 120 breast tumor biopsies were analyzed by agarose gel electrophoresis and none of them presented the fragmentation pattern characteristic of the apoptosis process. However, 33 per cent of the 105 breast cancer patients clearly showed the apoptotic pattern when DNA from blood cells was analyzed. None of the DNAs from healthy volunteer blood cells showed any trace of apoptosis. Since the breast cancer patients were not receiving chemo- or hormone therapy, the possible relationship between blood cortisol levels and the apoptotic pattern found in patient blood cells was investigated. Using a chemoluminescence immunodetection assay, similar cortisol levels were observed in breast cancer patient sera presenting or not apoptotic blood cells and in healthy volunteer sera. Analysis of the clinical data obtained from 60 of these patients showed that patients bearing tumors of smaller size (under 20 mm) were more susceptible to the apoptotic effect in blood cells. According to the Elston grade, it was observed that 7 of 12 patients with grade III tumors (58 per cent) presented apoptotic peripheral blood cells, in contrast to 10 of 48 patients with grade I and grade II tumors. These observations may reflect the immunosuppression characteristic of some breast cancer patients, which may contribute to tumor growth. Therefore, further studies are necessary to elucidate the factor(s) involved in such massive blood cell death.

[Non-communicable chronic diseases in Brazil: from risk factors to social impact]. / Doenças crônicas não-transmissíveis no Brasil: dos fatores de risco ao impacto social.

The current epidemiologic profile of Brazil includes both the diseases of underdevelopment and those associated with modern life. Consequently, the country faces the difficult task of carrying out health promotion and protection activities aimed at controlling communicable diseases as well as noncommunicable chronic diseases (NCDs). This study sought to describe the epidemiologic situation of Brazilian adults with regard to NCDs and to present available data on the quality of care provided for these diseases and their social impact. To these ends, a literature review was conducted for the period 1964-1995--that is, since the beginning of the production and dissemination of data on cardiovascular diseases, cancer, and diabetes. Of the 153 bibliographic references that were discovered, 97 were used. The social, political, economic, and health inequities that exist among Brazil's geographic regions are reflected in the national scientific production, which is concentrated in the Southeast and South. Most of the studies based on primary data come from those regions. Information is scarce from the North-east, except the city of Salvador. Therefore, the health profile of adults--including risk factors and morbidity and mortality--can be better delineated for residents of the South and Southeast of the country, whereas for the other regions the necessary information is practically nonexistent. Risk factors linked to life-style are as widespread and important in Brazil as they are in industrialized countries. Prevalence and mortality rates among persons with or without certain socio-environmental risks (such as low level of schooling or unskilled occupations) indicate that NCDs predominate in the lowest social strata. Inter-regional differences in the prevalence of arterial hypertension and diabetes mellitus, the most common fatal cardiovascular causes, and the predominant cancers, as well as morbidity and mortality in both sexes, illustrate the political, social, and economic inequities of development in each region. Comparisons with other countries of the incidence of cardiovascular diseases in a capital in the Northeast or mortality from cardiovascular diseases in the capitals in the South and Southeast show, in the first case, that Salvador has the highest incidence among the Western countries analyzed and, in the second case, that the mortality data rank among the top seven. Cardiovascular diseases and diabetes show increasing trends, with the exception of a small decline for ischemic heart disease and cerebrovascular disease in the municipality of São Paulo. Deaths rates in hospitals from specific cardiovascular diseases and avoidable complications of diabetes are high, especially among indigent patients as opposed to private patients. Premature mortality, as measured by productive years of life lost, reflects the poor quality of medical care and the absence of targeted control programs. These data, combined with other sources of information, such as consents for treatment and pensions paid for illness, give some idea of the impact of NCDs on the society. The authors point to the basic research that could be done in all the country's regions to serve as a basis for planning and implementing populational strategies to reduce risk factors and to treat and control chronic noncommunicable diseases in Brazil.

[Increasing risk of skin melanoma in Brazil]. / Risco crescente de melanoma de pele no Brasil.

The occurrence of cutaneous malignant melanoma in Brazil is analysed on the basis of available mortality data from the National Ministry of Health and from the incidence data of six Population-based Cancer Registries (Recife, Fortaleza, S. Paulo, Porto Alegre, Goiânia e Belém). The incidence in these State capitals has an intermediate pattern if compared to the world pictures. For Porto Alegre, the capital that had the highest rates, a comparison between the periods 1979-1982 and 1987 showed a proportional increases of 38% among males and 11% among females. The conclusion is reached that it is necessary to undertake studies in Brazil among fairskinned people from particular communities which may show a potentialized risk for the development of cutaneous melanoma in order to be able to define what kind of specific control actions should be developed.