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1.
Agric Syst ; 190: 103092, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-36567889

RESUMO

CONTEXT: During crises, adaptation or recovery measures or plans at local or national scales may not necessarily address longer-term or structural problems such as climate change mitigation. OBJECTIVE: This article describes farmers and policymakers' responses to mitigate the adverse effects of Covid-19 on the agricultural sector. We then assess the responses' possible effects on greenhouse gas (GHG) emissions. METHODS: The study is based on surveys conducted with farmers, traders, and extension staff in Burkina Faso, Colombia, and France, and literature. We used the Cool Farm Tool calculator to assess GHG emissions associated with fertilizer production, crop production and produce transportation to international markets for the three main cash crops in the three countries. RESULTS AND CONCLUSIONS: We identified contrasting responses by the agricultural sector mostly driven by changes in the consumption patterns at local or international levels. We also identified contrasting state responses to mitigate Covid-19. These responses at farm and policy scales led to similar trends in decreasing carbon dioxide (CO2) emissions across the studied countries. However, none of the studied countries linked Covid-19 response measures to long-term climate change mitigation actions. Therefore, an opportunity to sustain Covid-19 induced short-term decreases in GHG emissions was overlooked. SIGNIFICANCE: Analyzing the impacts that Covid-19 had on agricultural systems and the decision taken by policymakers to handle its direct and indirect effects can help society draw lessons on how to improve climate action.

2.
Prog Urol ; 19(12): 902-6, 2009 Dec.
Artigo em Francês | MEDLINE | ID: mdl-19963189

RESUMO

Lapeyronie's disease occurs mostly in middle age men and consists in pain and bending or arching of the penis during erection. This could negatively impact quality of life. A good knowledge of the physiopathology is necessary to adapt the different treatment modalities.


Assuntos
Induração Peniana/terapia , Humanos , Masculino , Induração Peniana/fisiopatologia
3.
Bull Cancer ; 96(10): 979-88, 2009 Oct.
Artigo em Francês | MEDLINE | ID: mdl-19744918

RESUMO

Several risk estimation models for breast or ovarian cancers have been developed these last decades. All these models take into account the family history, with different levels of sophistication. Gail model was developed in 1989 taking into account the family history (0, 1 or > or = 2 affected relatives) and several environmental factors. In 1990, Claus model was the first to integrate explicit assumptions about genetic effects, assuming a single gene dominantly inherited occurring with a low frequency in the population. BRCAPRO model, posterior to the identification of BRCA1 and BRCA2, assumes a restricted transmission with only these two dominantly inherited genes. BOADICEA model adds the effect of a polygenic component to the effect of BRCA1 and BRCA2 to explain the residual clustering of breast cancer. At last, IBIS model assumes a third dominantly inherited gene to explain this residual clustering. Moreover, this model incorporates environmental factors. We applied the Claus, BRCAPRO, BOADICEA and IBIS models to four clinical situations, corresponding to more or less heavy family histories, in order to study the consistency of the risk estimates. The three more recent models (BRCAPRO, BOADICEA and IBIS) gave the closer estimations. These estimates could be useful in clinical practice in front of complex analysis of breast and/or ovarian cancers family history.


Assuntos
Neoplasias da Mama/genética , Saúde da Família , Modelos Genéticos , Fatores Etários , Feminino , Genes BRCA1 , Genes BRCA2 , Predisposição Genética para Doença/genética , Humanos , Família Multigênica , Mutação/genética , Neoplasias Ovarianas/genética , Medição de Risco/métodos , Fatores de Risco
4.
Bull Cancer ; 96(9): 875-900, 2009 Sep.
Artigo em Francês | MEDLINE | ID: mdl-19751997

RESUMO

Organised since 1990 in France, cancer genetics has been strengthened since 2003 by the programme "Plan Cancer" which resulted in an improvement of the organisation of activities. The aim of this review is to present an update of the estimation of the needs of the population in this field for the next ten years, provided by a group of experts mandated by the French National Cancer Institute. Identification and management of major hereditary predispositions to cancer have a major impact on decrease in mortality and incidence. Sensitivity of criteria for the detection of BRCA1/2 mutations could be substantially improved by enlarging the indication for genetic testing to isolated cases of ovarian cancer occurring before 70 years and to familial cases occurring after this age limit. In the Lynch syndrome, the present criteria would have an excellent sensitivity for the detection of mutations in the mismatch repair (MMR) genes if the pre-screening of tumours on microsatellite instability (MSI) phenotype was effective, but these criteria are actually poorly applied. However, genetic testing should not be proposed to all the patients affected by tumours belonging to the spectrum of major predispositions and a fortiori to unaffected persons unless an affected relative has been identified as a carrier. The prescription of tests should continue to be strictly controlled and organised, in patients as well as in at-risk relatives. The enlargement of criteria and the improvement in the spreading of recommendations should result in an increase of genetic counselling activity and of the prescriptions of tests by a factor 2 to 4, and to a lesser extent in the clinical management of at risk persons. In a near future, it appears important to mandate experts on specific issues such as the determinants of the lack of effective application of tumour screening for MSI phenotype, the recommendations for the identification and the management of MYH-associated polyposis, or the predictive value of tumour characteristics for the identification of BRCA1/2 mutations. The expected increase in cancer genetics activity will need an optimal organisation to increase the throughput. Such measures will help in facing up to new predispositions that will probably be identified in common cancers.


Assuntos
Predisposição Genética para Doença/genética , Testes Genéticos , Necessidades e Demandas de Serviços de Saúde , Neoplasias/genética , Fatores Etários , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/genética , Neoplasias da Mama/prevenção & controle , Neoplasias Colorretais/diagnóstico , Neoplasias Colorretais/genética , Neoplasias Colorretais/prevenção & controle , Neoplasias Colorretais Hereditárias sem Polipose/genética , Feminino , Previsões , França , Genes BRCA1 , Genes BRCA2 , Testes Genéticos/psicologia , Necessidades e Demandas de Serviços de Saúde/organização & administração , Necessidades e Demandas de Serviços de Saúde/estatística & dados numéricos , Necessidades e Demandas de Serviços de Saúde/tendências , Humanos , Masculino , Mutação , Neoplasias/diagnóstico , Neoplasias/prevenção & controle , Neoplasias Ovarianas/diagnóstico , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/prevenção & controle
6.
Genes Chromosomes Cancer ; 42(1): 1-9, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15390180

RESUMO

Epidemiological studies have indicated that ataxia-telangiectasia (AT) heterozygotes in AT families have an increased risk of cancer, particularly of breast cancer (BC). However, in BC case-control studies, no significant differences were found in the frequency of ATM mutations between patients and controls. In such studies missense mutations were found more frequently than truncating mutations, suggesting that the cancer risk depends on mutation type. To investigate this possibility, we assessed the risk of BC according to the type and position of the ATM truncating mutation in extended AT families. DNA or RNA that had been isolated from blood or buccal cells of AT children and their relatives was screened for ATM germ-line mutations using restriction endonuclease fingerprinting, the protein truncation test, fluorescence-assisted mismatch analysis, and direct sequencing. The standardized incidence ratio of cancer associated with ATM heterozygosity status and type of mutation was estimated. We tested for genotype-phenotype correlations by simulations, permuting mutations among parental branches. No significant difference was found in the relative risk of breast cancer or any other type of cancer based on mutation type. However, the occurrence of BC may be associated with truncating mutations in certain binding domains of the ATM protein (e.g., P53/BRCA1, beta-adaptin, and FAT domains; P = 0.006). In this limited sample set, the presence of missense or truncating ATM mutations was not associated with different cancer risks. The risk of BC appeared to be associated with the alteration of binding domains rather than with the length of the predicted ATM protein.


Assuntos
Ataxia Telangiectasia/genética , Mutação , Neoplasias/epidemiologia , Neoplasias/genética , Proteínas Serina-Treonina Quinases/genética , Proteínas Mutadas de Ataxia Telangiectasia , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/genética , Proteínas de Ciclo Celular , Criança , Proteínas de Ligação a DNA , Feminino , França/epidemiologia , Humanos , Mutação de Sentido Incorreto , Polimorfismo de Nucleotídeo Único , Fatores de Risco , Deleção de Sequência , Proteínas Supressoras de Tumor
7.
J Clin Epidemiol ; 57(7): 662-71, 2004 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15358394

RESUMO

OBJECTIVE: The interest in studying gene-environment (GxE) interaction is increasing for complex diseases. A design combining both related and unrelated controls (e.g., population-based and siblings) is proposed to increase the power to detect GxE interaction. STUDY DESIGN AND SETTING: We used simulations to assess the efficiency of the case-combined-control design relative to a classical case-control study under a variety of assumptions. RESULTS: The case-combined-control design appears more efficient and feasible than a classical case-control study for detecting interaction involving rare exposures and/or genetic factors. The number of available sibling controls per case and the frequencies of the risk factors are the most important parameters for determining relative efficiency. Relative efficiencies decrease as the frequency of the gene (G) increases. A positive correlation in exposure (E) between siblings decreases relative efficiency. CONCLUSIONS: Although the case-combined-control design may not be efficient for common genes with moderate effects, it appears to be a useful alternative in certain situations where classical approaches remain unrealistic.


Assuntos
Meio Ambiente , Predisposição Genética para Doença , Neoplasias da Mama/genética , Estudos de Casos e Controles , Exposição Ambiental/efeitos adversos , Estudos de Viabilidade , Feminino , Humanos , Projetos de Pesquisa , Irmãos
8.
Gut ; 53(9): 1322-8, 2004 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15306593

RESUMO

BACKGROUND: Colorectal cancer (CRC) is the second most common cause of death from cancer in France. A family history of CRC increases an individual's risk of developing CRC. Family history has been suggested to have a greater impact on proximal than distal tumours. AIM: We estimated the familial risk of CRC and other cancers, and examined how risk varies according to localisation of the tumour in the colorectal tract. SUBJECTS: We recorded all cases of CRC diagnosed between 1993 and 1998 in the region served by the Calvados Cancer Registry. A trained interviewer asked all participants about their family history of cancer. STATISTICAL METHODS: Familial risk was estimated from a cohort analysis of the relatives of the CRC cases. The expected numbers of cancers were calculated from Calvados incidence rates. Familial relative risks were calculated using standardised incidence ratios. RESULTS: Our findings showed that colon cancer had a stronger familial/genetic component (relative risk (RR) 1.47) than rectal cancer (RR 0.98). The familial/genetic component appeared stronger for proximal colon cancer than for distal colon cancer only among women (RR 2.24 v RR 1.45). CRC appeared to be positively associated with leukaemia (RR 1.77), stomach cancer (RR 1.32), and testicular cancer (RR 3.13), and negatively associated with urinary bladder cancer (RR 0.57) within families. The cancer spectrum associated with CRC among younger participants included prostate (RR 1.93), uterus (RR 2.49), and thyroid (RR 3.85) cancers. CONCLUSION: If our results are confirmed, follow up guidelines for patients with a family history of CRC should depend on the sex and tumour site of affected relatives to avoid needless invasive screening.


Assuntos
Neoplasias do Colo/genética , Síndromes Neoplásicas Hereditárias/epidemiologia , Neoplasias Retais/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias do Colo/epidemiologia , Neoplasias do Colo/patologia , Neoplasias Colorretais/epidemiologia , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Feminino , França/epidemiologia , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-Idade , Síndromes Neoplásicas Hereditárias/patologia , Neoplasias Retais/epidemiologia , Neoplasias Retais/patologia , Sistema de Registros , Medição de Risco/métodos , Fatores Sexuais
9.
Eur J Cancer ; 39(13): 1904-11, 2003 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12932670

RESUMO

This study aimed to assess the familial relative risk for colorectal cancer (CRC) and its variation according to age and gender. A population-based family study was carried out in France, from 1993 to 1998, including 761 families. Familial CRC risks were estimated from a cohort analysis of the relatives. No obvious decrease in CRC risk was found with increasing age, except when either the proband, or the relative, were in the youngest age class. The effect of the relatives' and probands' ages on the CRC risk differed according to their gender. The cumulative risk of CRC increased at an earlier age in male relatives of probands younger than 60 years of age, than in female relatives. This result suggests that mechanisms specific to females, possibly interacting with genetic factors, explain the difference in the cumulative risks between families with male and female probands.


Assuntos
Neoplasias Colorretais/genética , Adolescente , Adulto , Distribuição por Idade , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Estudos de Coortes , Neoplasias Colorretais/epidemiologia , Feminino , França/epidemiologia , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Linhagem , Vigilância da População , Medição de Risco , Fatores de Risco , Distribuição por Sexo
10.
Int J Cancer ; 93(2): 288-93, 2001 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-11410879

RESUMO

Epidemiological studies have suggested that ataxia-telangiectasia (AT) heterozygotes have a predisposition to cancer, especially breast cancer in women. Now, haplotyping can identify heterozygotes for AT mutation (ATM) in AT families, allowing the risk of cancer associated with ATM heterozygosity status to be better assessed. We report a family study of AT patients, in which we estimated the risk of cancer according to ATM heterozygosity status. We analyzed demographic characteristics and occurrence of cancer in 1,423 relatives of AT patients. Haplotyping was performed in living relatives. The probability of being heterozygotes for ATM was calculated for deceased relatives. The risk of developing cancer was estimated in the cohort of relatives, and expected numbers of cancer cases were calculated from French age period-specific incidence rates. The number of cancers at all sites in the total population of relatives was not higher than expected. However, significant heterogeneity was found according to ATM heterozygosity status. This is mainly due to the increased risk of breast cancer previously observed in obligate heterozygotes. In obligate heterozygotes, relative risk (RR) was non-significantly increased for thyroid cancer, leukemia and liver cancer. Risks of ovarian, lung, pancreatic, kidney, stomach and colorectal cancers were non-significantly increased in the group with 0.5 probability of being heterozygotes. The RR was not significantly increased for any site of cancer, except for breast. Therefore, there is no evidence that specific screening of relatives of AT patients would be justified at particular sites other than the breast. However, the amplitude of the risk of breast cancer estimated in heterozygous women does not appear to justify a separate screening program from that already available to women with a first-degree relative affected by breast cancer.


Assuntos
Ataxia Telangiectasia/complicações , Heterozigoto , Neoplasias/etiologia , Proteínas Serina-Treonina Quinases/genética , Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia , Proteínas de Ciclo Celular , Criança , Pré-Escolar , Segregação de Cromossomos , Proteínas de Ligação a DNA , Feminino , França/epidemiologia , Predisposição Genética para Doença , Haplótipos , Humanos , Masculino , Neoplasias/epidemiologia , Fatores de Risco , Proteínas Supressoras de Tumor
11.
Am J Epidemiol ; 153(3): 265-74, 2001 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-11157414

RESUMO

The interest in studying gene-environment interaction is increasing for complex diseases. However, most methods of detecting gene-environment interactions may not be appropriate for the study of interactions involving rare genes (G:) or uncommon environmental exposures (E:), because of poor statistical power. To increase this power, the authors propose the counter-matching design. This design increases the number of subjects with the rare factor without increasing the number of measurements that must be performed. In this paper, the efficiency and feasibility (required sample sizes) of counter-matching designs are evaluated and discussed. Counter-matching on both G: and E: appears to be the most efficient design for detecting gene-environment interaction. The sensitivity and specificity of the surrogate measures, the frequencies of G: and E:, and, to a lesser extent, the value of the interaction effect are the most important parameters for determining efficiency. Feasibility is also more dependent on the exposure frequencies and the interaction effect than on the main effects of G: and E: Although the efficiency of counter-matching is greatest when the risk factors are very rare, the study of such rare factors is not realistic unless one is interested in very strong interaction effects. Nevertheless, counter-matching appears to be more appropriate than most traditional epidemiologic methods for the study of interactions involving rare factors.


Assuntos
Meio Ambiente , Modelos Genéticos , Estudos de Casos e Controles , Estudos de Coortes , Métodos Epidemiológicos , Estudos de Viabilidade , Genética , Humanos , Análise por Pareamento , Projetos de Pesquisa , Sensibilidade e Especificidade
12.
Int J Epidemiol ; 29(2): 214-23, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10817116

RESUMO

BACKGROUND: Studies have found that reproductive factors might have a variable effect on the occurrence of breast cancer (BC) according to the existence or not of a family history of BC. The effect of a family history of BC on the risk of BC may also vary according to the age at diagnosis and the degree of kinship. This may confound the relation between familial risk and reproductive factors. A combined analysis was performed to study the interaction between familial risk and reproductive factors according to degree of familiality, age at interview and menopausal status. METHODS: The present analysis included 2948 cases and 4170 controls in seven case-control studies from four countries. The combined relative risks were estimated using a Bayesian random-effects logistic regression model. RESULTS: The main effects of reproductive life factors on the risk of BC are in agreement with previous studies. Two-way interactions between subject's age or menopausal status and a family history of BC were not significant. Although the three-way interaction between age, familial risk and parity was not significant, familial risk seemed to be increased slightly for women with high parity compared with women with low parity in the older age group, and seemed to be slightly decreased for women with high parity compared with women with low parity in younger women. The subject's age also appeared to have an effect on the interaction between familial risk and the age at first childbirth (P = 0.1). CONCLUSIONS: A possible influence of reproductive and menstrual factors on familial risk of BC has been suggested previously and was also evident in the present study. Three-way interactions between age, family history and parity or age at first childbirth might exist and they merit further investigation.


Assuntos
Neoplasias da Mama/epidemiologia , Menopausa , História Reprodutiva , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Teorema de Bayes , Neoplasias da Mama/etiologia , Neoplasias da Mama/genética , Suscetibilidade a Doenças/epidemiologia , Feminino , Saúde Global , Humanos , Incidência , Pessoa de Meia-Idade , Linhagem , Sistema de Registros/estatística & dados numéricos , Estudos Retrospectivos , Fatores de Risco
13.
Cardiovasc Res ; 43(2): 398-407, 1999 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-10536670

RESUMO

OBJECTIVES: Anthracyclines cause apoptotic death in many cell types through activation of the ceramide pathway. We tested the hypothesis that doxorubicin induces cardiac myocyte apoptosis through ceramide generation. METHODS: Adult rat ventricular myocytes were grown in the presence of 10% fetal calf serum, and exposed to 0.5 microM doxorubicin (Dox) for 1 h on the day of cell isolation (day 0). We used the membrane-permeant ceramide analog C2-ceramide (C2-cer) to mimic the effects of endogenous ceramide and PDMP to induce endogenous ceramide accumulation. Apoptosis was assessed upon morphological criteria and DNA fragmentation by the TUNEL method and agarose gel electrophoresis. Ceramide concentration was assessed using the DAG kinase assay. RESULTS: Myocyte exposure to Dox was associated with cellular and nuclear alterations typical of apoptosis on day 7 but not on day 3. At day 7, the percentage of TUNEL-positive myocytes was markedly increased in Dox-treated cultures compared to control (Cl) cultures (82 +/- 3 vs. 12 +/- 1%, n = 7; p < 0.001); internucleosomal DNA fragmentation was confirmed by the observation of DNA ladders. These alterations were associated with an increase in the intracellular ceramide concentration (1715 +/- 243 vs. 785 +/- 99 pmol/mg prot, n = 5; p < 0.01), a phenomenon also detected on day 3 (731 +/- 59 vs. 259 +/- 37 pmol/mg prot, n = 5; p < 0.001). Incubation of myocytes at day 0 with 50 microM C2-cer induced rapid cell shrinkage and DNA fragmentation (45 +/- 3 vs. 10 +/- 1% TUNEL-positive myocytes on day 1 in C2-cer-treated and Cl cultures, respectively; n = 6, p < 0.001). Myocyte exposure to 10 microM PDMP for 7 days (n = 5), caused ceramide accumulation (1.7-fold increase vs. Cl, p < 0.01), and a marked increase in the percentage of TUNEL-positive myocytes (62 +/- 6 vs. 11 +/- 3% in Cl cultures, p < 0.001). Ventricles of rats injected intraperitoneally with a cumulative dose of 14 mg/kg Dox over a period of 2 weeks also showed an increased ceramide concentration 2 weeks later (11.01 +/- 0.64 vs. 5.24 +/- 0.88 pmol/mg prot, n = 6; p < 0.001). CONCLUSION: Our study confirms the existence of a functional ceramide pathway related to apoptosis in cardiac myocytes, and points to its possible involvement in doxorubicin-induced cardiomyopathy.


Assuntos
Antibióticos Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Cardiomiopatias/metabolismo , Ceramidas/metabolismo , Doxorrubicina/farmacologia , Miocárdio/metabolismo , Animais , Células Cultivadas , Fragmentação do DNA , Inibidores Enzimáticos/farmacologia , Marcação In Situ das Extremidades Cortadas , Masculino , Morfolinas/farmacologia , Ratos , Ratos Wistar , Fatores de Tempo
14.
Br J Cancer ; 80(7): 1042-5, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10362113

RESUMO

Epidemiological studies in ataxia telangiectasia (AT) families have suggested that AT heterozygotes could have an increased cancer risk, especially breast cancer (BC) in women. It has also been suggested that an increased sensibility of AT heterozygotes to the effect of ionizing radiation could be responsible for the increased BC risk. BC relative risk (RR) estimation in AT heterozygotes within families ascertained through AT children is presented here. Family data collected included demographic characteristics, occurrence of cancers, past radiation exposures and blood samples. DNA samples were studied using seven ATM linked microsatellites markers allowing AT haplotypes reconstitution. The relative risk of BC was assessed using French estimated incidence rates. A significant increase risk of BC is found among obligate ATM heterozygotes with a point estimate of 3.32 (P = 0.002). BC relative risk calculated according to age is significantly increased among the obligate ATM heterozygotes female relatives with an age < or = 44 years (RR = 4.55, P = 0.005). The BC relative risk is statistically borderline among the obligate ATM heterozygote female relatives with an age > or = 45 years (RR = 2.48, P = 0.08). The estimated BC relative risk among ATM heterozygotes is consistent with previously published data. However, the increased risk is only a little higher than classical reproductive risk factors and similar to the risk associated with a first-degree relative affected by BC.


Assuntos
Ataxia Telangiectasia/complicações , Ataxia Telangiectasia/genética , Neoplasias da Mama Masculina/genética , Neoplasias da Mama/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/epidemiologia , Neoplasias da Mama Masculina/epidemiologia , Criança , Pré-Escolar , Feminino , França , Triagem de Portadores Genéticos , Haplótipos , Heterozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Medição de Risco
15.
J Natl Cancer Inst Monogr ; (26): 49-54, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10854486

RESUMO

Advances in molecular genetic techniques have led to an increased ability to examine gene-environment interactions. Studies to detect gene-environment interactions are motivated by different situations, including 1) most identified cancer genes having associated lifetime risks less than 100% (i.e., incomplete penetrance), 2) hereditary factors that control the metabolism of carcinogens that may modulate risk of disease as hypothesized in pharmacogenetics, and 3) inconsistent associations across studies between a cancer and a suspected risk factor. The above situations and others have led to increased study of interaction between genetic and environmental factors. Less studied so far, but with increased potential for the future, is interaction between identified genes. Gene-gene interaction studies would also be motivated by the situations described above. Approaches to detect gene-environment and gene-gene interactions are reviewed. Available risk estimates, required types of subjects, and feasibility of the proposed study designs are discussed; efficiency and power for interaction assessment are summarized where available. In general, most designs allow for estimating risk associated with a genetic factor, environmental factor, and interaction effect. Although power and efficiency for detecting interactions have been assessed for specific situations in some of the methods, further investigations are needed to define the efficiency spectra of each design.


Assuntos
Genes , Projetos de Pesquisa , Estudos de Casos e Controles , Exposição Ambiental , Família , Humanos
16.
Br J Cancer ; 77(9): 1525-36, 1998 May.
Artigo em Inglês | MEDLINE | ID: mdl-9652773

RESUMO

In this paper, a combined analysis was performed to study the interaction between familial risk and reproductive life factors. In particular, the interaction between familial risk and breast cell mitotic activity (BCMA), as assessed by duration of ovarian activity, was investigated because of the potential importance of mitotic activity on genetically susceptible cells. The present analysis included 3152 cases and 4404 controls in seven case-control studies from four countries. The interaction effect was estimated in each study separately, then combined using two different methods: a multivariate weighted average and a Bayesian random-effects model. The main effects of reproductive life factors on the risk of breast cancer were in agreement with the previous findings. In particular, an increased duration of BCMA before the first childbirth and over life was found to increase the risk of breast cancer (P < 0.001). Slightly increasing but non-significant, familial risks were observed with increasing number of children (P = 0.17), increasing age at first childbirth (P > 0.2) and increasing duration of BCMA (P > 0.2). There was no modification in familial risk with age at menarche and no clear pattern with menopause characteristics. A weak influence of reproductive and menstrual factors on the familial risk emerged from the present study.


Assuntos
Neoplasias da Mama , Reprodução , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/genética , Estudos de Casos e Controles , Feminino , Humanos , Menopausa , Pessoa de Meia-Idade , Medição de Risco , Fatores de Risco
18.
Am J Hum Genet ; 61(3): 678-90, 1997 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9326334

RESUMO

Considerable progress has been made in the characterization of the genetic component of breast cancer (BC). However, BC still remains a complex disease involving a genetic component and many other risk factors essentially linked to reproductive-life factors. To search for interactions between genetic and reproductive-life factors in the etiology of BC, a systematic family study was performed in two French hospitals from December 1987 to January 1990 and led to recruitment of 288 families, the IGRC data ("IGRC" refers to the Institut Gustave Roussy and Institut Curie, where the data were obtained). Detailed information on reproductive factors was recorded for probands and female first-degree relatives. Segregation analysis of BC was conducted by taking into account a variable age at onset of disease, by use of the class D regressive logistic model, as implemented in the REGRESS computer program. Segregation analyses of BC in IGRC data showed evidence for the segregation of a dominant gene and additional sister-sister dependence, both when reproductive factors were ignored and when they were included. A significant interaction was detected between the dominant gene and age when reproductive factors were taken into account. Among the reproductive factors included in segregation analysis, parity was found to interact with the dominant-gene effect, and there was an indication of an interaction, albeit not significant, between the dominant gene and age at menarche. Whereas the usual protective effect conferred on breast-cancer risk by high parity remained in nonsusceptible women, it disappeared in susceptible women. The increased BC risk associated with a late age at menarche was higher in susceptible women than in nonsusceptible women. Interactions between inherited predisposition to BC and reproductive factors were detected here for the first time by segregation analysis. It would be of major interest to confirm these results by family studies in other populations.


Assuntos
Neoplasias da Mama/etiologia , Neoplasias da Mama/genética , Reprodução/fisiologia , Aborto Espontâneo , Adulto , Idade de Início , Idoso , Idoso de 80 Anos ou mais , Feminino , França , Genes Dominantes , Humanos , Funções Verossimilhança , Menarca , Menopausa , Pessoa de Meia-Idade , Paridade , Gravidez , Análise de Regressão , Fatores de Risco
19.
J Biol Chem ; 272(27): 17196-203, 1997 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-9202042

RESUMO

The role of cytosolic phospholipase A2 (cPLA2) in the regulation of ceramide formation was examined in a cell line (L929) responsive to the cytotoxic action of tumor necrosis factor alpha (TNFalpha). In L929 cells, the addition of TNFalpha resulted in the release of arachidonate, which was followed by a prolonged accumulation of ceramide occurring over 5-12 h and reaching 250% over base line. The formation of ceramide was accompanied by the hydrolysis of sphingomyelin and the activation of three distinct sphingomyelinases (neutral Mg2+-dependent, neutral Mg2+-independent, and acidic enzymes). The variant cell line C12, which lacks cPLA2, is resistant to the cytotoxic action of TNFalpha. TNFalpha was able to activate nuclear factor kappaB in both the wild-type L929 cells and the C12 cells. However, TNFalpha was unable to cause the release of arachidonate or the accumulation of ceramide in C12 cells. C6-ceramide overcame the resistance to TNFalpha and caused cell death in C12 cells to a level similar to that in L929 cells. The introduction of the cPLA2 gene into C12 cells resulted in partial restoration of TNFalpha-induced arachidonate release, ceramide accumulation, and cytotoxicity. This study suggests that cPLA2 is a necessary component in the pathways leading to ceramide accumulation and cell death.


Assuntos
Ceramidas/metabolismo , Fosfolipases A/metabolismo , Fator de Necrose Tumoral alfa/farmacologia , Animais , Ácido Araquidônico/metabolismo , Divisão Celular/efeitos dos fármacos , Citosol/enzimologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Cinética , Magnésio/metabolismo , Camundongos , NF-kappa B/metabolismo , Fosfolipases A2 , Esfingomielinas/metabolismo , Células Tumorais Cultivadas
20.
J Biol Chem ; 271(32): 19251-5, 1996 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-8702606

RESUMO

Development of atherosclerosis is believed to involve proliferation of smooth muscle cells (SMC). Our laboratory previously demonstrated that the growth of bovine aortic SMC was stimulated by mildly oxidized low density lipoproteins (oxLDL) and that the mitogenic effect of oxLDL was greater than that induced by native LDL (Augé, N., Pieraggi, M. T., Thiers, J. C., Nègre-Salvayre, A., and Salvayre R.(1995) Biochem. J. 309, 1015-1020). Since the lipid mediator ceramide has been described to be proliferative, the present work aimed at studying the potential involvement of the so-called sphingomyelin-ceramide pathway in the signal transduction cascade induced by oxLDL. Incubation of SMC with UV-oxidized LDL induced sphingomyelin hydrolysis (32%), which peaked at 60 min and was accompanied by a concomitant increase of intracellular ceramide level. The effect of oxidized LDL on sphingomyelin turnover exhibited the same LDL dose dependence as their mitogenic effect. Exogenous bacterial sphingomyelinase induced sphingomyelin hydrolysis and ceramide generation and also stimulated cell growth, in contrast to exogenous phospholipases A2, C, or D. This mitogenic effect was reproduced by incubating the cells with the cell-permeant ceramides, N-acetyl- and N-hexanoylsphingosines. Altogether, these data strongly suggest for the first time that activation of the sphingomyelin-ceramide pathway may play a pivotal role in the oxLDL-induced SMC proliferation and atherogenesis.


Assuntos
Ceramidas/metabolismo , Lipoproteínas LDL/fisiologia , Transdução de Sinais , Esfingomielinas/metabolismo , Animais , Bovinos , Divisão Celular/fisiologia , Células Cultivadas , Humanos , Hidrólise , Músculo Liso Vascular/citologia , Oxirredução , Esfingomielina Fosfodiesterase/metabolismo
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