RESUMO
Reliance on anthelmintic drugs to control internal parasites in sheep is no longer sustainable because of the development of resistance to these drugs in parasite populations. Genetic selection may offer an alternative long-term solution, as differences in parasite resistance exist both within and among sheep breeds. However, selection for parasite resistance may have correlated effects on other production traits. The objectives of this study were to estimate genetic parameters for weaning (WFEC) and postweaning (PWFEC) fecal egg counts (FEC) and assess their relationship with birth (BWT), weaning (WWT), and postweaning (PWWT) BW in Katahdin lambs. The study used WFEC (n = 2,537), PWFEC (n = 3.421), BWT (n = 12,869), WWT (n = 10,961), and PWWT (n = 7,812) from 12,869 lambs measured between 2003 and 2015 in 13 flocks enrolled in the U.S. National Sheep Improvement Program. Animal and sire models were fitted to the data using the ASReml statistical package. Records were corrected for fixed effects of dam age, joint effect of type of birth and rearing, and management group (defined by joint effects of flock, sex, and birth year and season); lamb age in days at each measurement time was fitted as a covariate. Maternal additive and maternal permanent environmental effects were not significant (P > 0.05), but litter effects influenced (P < 0.01) both WFEC and PWFEC. Heritability estimates ranged from 0.18 to 0.26 for WFEC and 0.23 to 0.46 for PWFEC, depending on the model used. Heritability estimates from sire models were higher than estimates from animal models. Direct additive, litter, residual, and phenotypic correlations between WFEC and PWFEC were 0.82, 0.25, 0.15, and 0.29, respectively. Bivariate analyses revealed low to moderate correlations between BW and FEC. Moderate heritabilities for FEC in this study indicated that genetic progress for this trait can be achieved in Katahdin lambs and that selection for low FEC should have little or no effect on BW.
Assuntos
Anti-Helmínticos/uso terapêutico , Fezes/parasitologia , Helmintíase Animal/parasitologia , Helmintos/isolamento & purificação , Contagem de Ovos de Parasitas/veterinária , Doenças dos Ovinos/parasitologia , Animais , Peso Corporal/genética , Cruzamento , Clima , Feminino , Masculino , Fenótipo , Estações do Ano , Ovinos , DesmameRESUMO
Recent studies on sheep and goat farms in the southern United States indicate that multiple-anthelmintic resistance in Haemonchus contortus is becoming a severe problem. Though many factors are involved in the evolution of resistance, the proportion of the parasite population under drug selection is believed to be the single most important factor influencing how rapidly resistance develops. Therefore, where prevention of resistance is an important parallel goal of worm control, it is recommended to leave a portion of the animals untreated. Recently, a novel system called FAMACHA was developed in South Africa, which enables clinical identification of anemic sheep and goats. When H. contortus is the primary parasitic pathogen, this system can be applied on the farm level to reduce the number of treatments administered, thereby increasing the proportion of the worm population in refugia. Since most studies validating the FAMACHA method have been performed in South Africa, it is important that the method be tested in other regions before its use is broadly recommended. We performed a validation study of FAMACHA by testing the system in sheep (n = 847) and goats (n = 537) of various breeds and ages from 39 farms located in Arkansas, Georgia, Louisiana, Florida, and the US Virgin Islands. The color of the ocular conjunctiva of all animals were scored on a 1-5 scale using the FAMACHA card, and blood samples were collected from each animal for determination of packed cell volume (PCV). Fecal samples were also collected from a majority of the animals tested for performance of fecal egg counts (FEC). Correlations between PCV and eye scores, PCV and FEC, and FEC and eye scores were all highly significant for both sheep and goats (P < 0.001). Data for both FAMACHA scores and PCV were evaluated using two separate criteria for anemia: eye score values of 3, 4 and 5 or 4 and 5, and PCV values of < or =19 or < or =15 were considered anemic. Specificity was maximized when eye score values of 4 and 5 were considered anemic and PCV cut off for anemia was < or =19, but sensitivity was low. In contrast, sensitivity was 100% for both sheep and goats when eye score values of 3, 4 and 5 were considered anemic and PCV cut off was < or =15, but specificity was low. In both sheep and goats, predictive value of a negative was greater than 92% for all anemia and eye score categories, and was greater than 99% for both eye score categories when an anemia cutoff of < or =15 was used. Predictive value of a positive test was low under all criteria indicating that many non-anemic animals would be treated using this system. However, compared to conventional dosing practices where all animals are treated, a large proportion of animals would still be left untreated. These data indicate that the FAMACHA method is an extremely useful tool for identifying anemic sheep and goats in the southern US and US Virgin Islands. However, further studies are required to determine optimal strategies for incorporating FAMACHA-based selective treatment protocols into integrated nematode control programs.
Assuntos
Anemia/veterinária , Cor de Olho , Doenças das Cabras/parasitologia , Hemoncose/veterinária , Haemonchus/crescimento & desenvolvimento , Doenças dos Ovinos/parasitologia , Anemia/diagnóstico , Anemia/parasitologia , Animais , Arkansas , Reações Falso-Negativas , Reações Falso-Positivas , Fezes/parasitologia , Florida , Georgia , Doenças das Cabras/diagnóstico , Cabras , Hemoncose/diagnóstico , Hemoncose/parasitologia , Hematócrito/veterinária , Louisiana , Contagem de Ovos de Parasitas/veterinária , Valor Preditivo dos Testes , Ovinos , Doenças dos Ovinos/diagnóstico , Ilhas Virgens AmericanasRESUMO
OBJECTIVE: To compare the incidence of type 2 diabetes between low-income Mexican-Americans residing in San Antonio, Texas, and low-income residents in Mexico City, Mexico. RESEARCH DESIGN AND METHODS: Using data from the San Antonio Heart Study and the Mexico City Diabetes Study, we compared the incidence of type 2 diabetes in 35- to 64-year-old low-income Mexican-American residents of San Antonio with similarly aged low-income residents of Mexico City. Because of the different follow-up times in the two studies, Poisson regression was used to compare the rates of diabetes. Potential risk factors for diabetes were also analyzed to determine whether they explained or contributed to a difference in incidence. RESULTS: The age- and sex-adjusted incidence of type 2 diabetes was significantly higher in San Antonio (RR 2.01) compared with Mexico City. This difference was seen primarily in the oldest age group (55-64 years of age) and remained statistically significant after adjusting for a number of diabetes risk factors, including demographic, anthropometric, and metabolic variables. Follow-up rates were similar in both cities. CONCLUSIONS: We conclude that there was a higher incidence of type 2 diabetes in San Antonio than in Mexico City, and that difference occurred primarily in individuals in the oldest age group. The potential mediating factors we examined did not account for this difference. Other factors, such as exercise and diet, which were not available for analysis in this study, in addition to a cohort effect, may have contributed to the difference in incidence of type 2 diabetes in the two cities. In addition, there was no evidence of a higher case fatality among diabetic individuals from Mexico City compared with San Antonio.
Assuntos
Diabetes Mellitus Tipo 2/epidemiologia , Adulto , Distribuição por Idade , Glicemia/metabolismo , Índice de Massa Corporal , HDL-Colesterol/sangue , Demografia , Feminino , Seguimentos , Teste de Tolerância a Glucose , Humanos , Renda , Masculino , México/epidemiologia , Pessoa de Meia-Idade , Distribuição de Poisson , Pobreza , Análise de Regressão , Fatores de Risco , Fatores Sexuais , Texas/epidemiologia , Triglicerídeos/sangue , População UrbanaRESUMO
OBJECTIVE: Several studies have examined the influence of smoking cessation on weight gain. However, to date no study has examined this association in Mexican Americans (MA). DESIGN: Using data collected from the San Antonio Heart Study, a population-based study of diabetes and cardiovascular disease, we examined the association between smoking cessation and weight gain in 1930 Mexican Americans and 1126 non-Hispanic whites (NHW). Smoking cessation was defined as self-reported smoking at baseline but not at follow-up. RESULTS: Although there was no significant ethnic difference in the prevalence of smoking at baseline (27.2% in MA and 25.4% in NHW, P = 0.309), a greater proportion of MA smoked at follow-up compared to NHW (19.7% vs 16.5%, P = 0.037). However, there was no significant ethnic difference in the percentage of individuals who stopped smoking during the follow-up period. A two-fold greater percentage of MA quitters than NHW quitters became overweight or obese, defined as a body mass index greater than or equal to 25 kg/m2 (7.4% vs 3.1%). However, this difference did not quite reach statistical significance (P = 0.072). Using linear regression to predict change in weight or body mass index from baseline to follow-up, smoking cessation was predictive of either weight gain or BMI gain in both ethnic groups. However, smoking status accounted for only 1.0% of the variance in these outcomes, and the estimated risk of becoming overweight or obese attributable to smoking cessation was only 7.4% in MA and 3.1% in NHW. CONCLUSION: We conclude that there is an ethnic difference in the influence of smoking cessation on weight gain in MA and NHW. However, in both ethnic groups this effect is quite small and makes only a slight contribution to the overall increase in prevalence of obesity in this population.
Assuntos
Hispânico ou Latino , Obesidade/epidemiologia , Obesidade/etiologia , Abandono do Hábito de Fumar , População Branca , Adulto , Índice de Massa Corporal , Feminino , Humanos , Modelos Lineares , Masculino , México/etnologia , Aumento de PesoRESUMO
Acanthosis nigricans (AN) is a skin condition associated with hyperinsulinemia and insulin resistance and has been shown to be a risk factor for type 2 diabetes. The influence of genetic factors on AN and the basis of its association with type 2 diabetes and its risk factors are unknown. Using data from 397 participants from two Mexican American family studies, we investigated the heritability of AN and its genetic correlation with other diabetes risk factors. AN was examined as both a continuous trait and a dichotomous trait by means of a previously described validated scale. The results indicated that the heritability (h2) for AN, when examined as a continuous trait, was high (0.58+/-0.10) and statistically significant (P<0.001). The h2 for AN as a dichotomous trait was estimated to be moderate (0.23+/-0.05) and was also significant (P=0.018). The additive genetic correlations between AN (either as a continuous trait or a dichotomous trait) and type 2 diabetes and its risk factors, including body mass index and fasting insulin, were high or moderately high and statistically significant. The random environmental correlations, by contrast, were low and statistically insignificant. These data suggest that genes that influence AN have pleiotropic effects on diabetes and its risk factors.
Assuntos
Acantose Nigricans/genética , Diabetes Mellitus Tipo 2/genética , Americanos Mexicanos/genética , Acantose Nigricans/complicações , Adulto , Índice de Massa Corporal , Diabetes Mellitus Tipo 2/etiologia , Feminino , Humanos , Insulina/sangue , Masculino , Pessoa de Meia-Idade , Linhagem , Fenótipo , Fatores de Risco , TexasRESUMO
This paper presents preliminary data regarding the prevalence and risk factors for autoimmune thyroid disease in IDDM probands ascertained from the Children's Hospital of Pittsburgh IDDM Registry for 1950-1965 (n = 669). Living IDDM probands who participated in the 1990 follow-up survey (n = 380) were recruited for the Familial Autoimmune and Diabetes Study. Siblings and parents were also invited to participate. To date, 255 IDDM probands and 597 parents and siblings have been evaluated. The diagnosis of autoimmune thyroid disease was based on a clinical evaluation, medical history, and laboratory determinations. Graves disease was rare in this cohort (n = 5). However, Hashimoto's thyroiditis was common among women. Prevalence rates ranged from 54% for IDDM women age < 40 years to 75% for those > 50 years. Corresponding age-specific estimates for female relatives were 22% and 44%, respectively. Approximately one-half of the Hashimoto's individuals were euthyroid; they were more likely to have other autoantibodies and a positive family history than those who were hypothyroid or had no thyroid disease. Genetic analyses revealed a 2-fold increase in DQA1*0501-DQB1*0201 among the Hashimoto's compared to the non-Hashimoto's haplotypes. These findings suggested that Hashimoto's thyroiditis was common in IDDM families, which may be due, in part, to common disease susceptibility genes.
Assuntos
Doenças Autoimunes/epidemiologia , Diabetes Mellitus Tipo 1/epidemiologia , Tireoidite Autoimune/epidemiologia , Adolescente , Adulto , Idoso , Doenças Autoimunes/genética , Criança , Pré-Escolar , Estudos de Coortes , Comorbidade , Suscetibilidade a Doenças , Feminino , Doença de Graves/epidemiologia , Doença de Graves/genética , Antígenos HLA-DQ/genética , Cadeias alfa de HLA-DQ , Cadeias beta de HLA-DQ , Haplótipos/genética , Humanos , Masculino , Pessoa de Meia-Idade , Pais , Pennsylvania/epidemiologia , Prevalência , Fatores de Risco , Tireoidite Autoimune/genéticaRESUMO
No abstract available for this article.
RESUMO
BACKGROUND AND METHODS: The safety of long-term immunosuppression with cyclosporine in renal-transplant recipients is not well understood. This drug may cause a progressive toxic nephropathy, but it also preserves renal function because it prevents rejection. To determine the effect of cyclosporine on renal function and graft rejection, we conducted a retrospective analysis of data on 1663 renal-transplant recipients at six centers. RESULTS: The rate of graft survival was 78 percent (median follow-up, 36 months). Grafts were was lost in 279 patients (17 percent), mostly because of acute rejection (68 patients) or chronic graft dysfunction that was unresponsive to a reduction in the dose of cyclosporine (125 patients); 92 patients died with functioning grafts. The median change in the serum creatinine concentration in all patients after transplantation was less than 0.001 mg per deciliter per month (< 0.09 mumol per liter per month). Patients who had episodes of rejection had decreased rates of long-term graft function and survival. Eight percent of patients with functioning grafts at one year had first episodes of rejection more than one year after transplantation. These late first rejections were associated with noncompliance with therapy (in 34 percent), blood cyclosporine concentrations that were marginally lower than those of patients who had no episodes of rejection, and a low rate of successful reversal of rejection (77 percent, vs. 97 percent in patients with rejection during the first year; P < 0.001). CONCLUSIONS: The majority of renal-transplant patients tolerate long-term cyclosporine therapy without evidence of progressive toxic nephropathy. Graft failure is most often due to rejection.
Assuntos
Ciclosporina/uso terapêutico , Sobrevivência de Enxerto/efeitos dos fármacos , Transplante de Rim , Adulto , Creatinina/sangue , Ciclosporina/efeitos adversos , Feminino , Seguimentos , Rejeição de Enxerto/complicações , Rejeição de Enxerto/prevenção & controle , Humanos , Rim/efeitos dos fármacos , Rim/fisiopatologia , Masculino , Recidiva , Insuficiência Renal/induzido quimicamente , Estudos RetrospectivosRESUMO
Alzheimer's disease is the leading cause of dementia in the elderly. Most patients do not have an obvious family history and are classified as sporadic. Genetic factors in early and late-onset Alzheimer's disease are now well documented. This paper reviews the known genetic loci associated with Alzheimer's disease with an emphasis on the role of apolipoprotein E in late-onset familial and sporadic disease. Apolipoprotein E allele 4 is a susceptibility gene that is found in approximately 50% of patients with Alzheimer's disease. Hypotheses about apolipoprotein E function that may lead to Alzheimer's disease are also discussed.
Assuntos
Doença de Alzheimer/genética , Idade de Início , Animais , Apolipoproteínas E/genética , Apolipoproteínas E/fisiologia , Cromossomos/genética , HumanosRESUMO
Eight boys aged 9.5 to 17 years, on regular hemodialysis for chronic renal failure, were treated for 0.4 to 1.3 years with the anabolic steroid oxandrolone. The effects on linear growth, skeletal maturation, cell mass, and the fasting levels and response to intravenous glucose of BG, IRI, NEFA, BCAA, and IRG were measured. Following treatment there was a significant increase in mean growth velocity, growth velocity standard deviation score related to bone age, and cell mass. Overall skeletal maturation was not accelerated, and only a small advance in pubertal status was seen. There was a decrease in fasting levels of BG and NEFA; fasting BCAA and IRG were increased. The response to intravenous glucose was altered; there was a decrease in peak BG response, an increase in peak IRI response, and a more marked fall in plasma NEFA and BCAA levels. Fasting IRG levels correlated with fasting BG levels, and fell significantly following intravenous glucose both before and after treatment. Hepatotoxicity, which was reversible, was seen in a ninth boy who did not complete the study. The only other side effect, salt and water retention, was controlled by a reduction in oxandrolone dosage. These preliminary results suggest that anabolic steroids may be useful to stimulate anabolism and growth in uremic children, and that their effect is mediated by an increase in insulin secretion and/or an improvement in tissue sensitivity to insulin. Further studies with careful monitoring are required to substantiate the effect on final height and the risks involved.