Bayesian inference to study genetic control of resistance to gray leaf spot in maize.

Gray leaf spot (GLS) is a major maize disease in Brazil that significantly affects grain production. We used Bayesian inference to investigate the nature and magnitude of gene effects related to GLS resistance by evaluation of contrasting lines and segregating populations. The experiment was arranged in a randomized block design with three replications and the mean values were analyzed using a Bayesian shrinkage approach. Additive-dominant and epistatic effects and their variances were adjusted in an over-parametrized model. Bayesian shrinkage analysis showed to be an excellent approach to handle complex models in the study of genetic control in GLS, since this approach allows to handle overparametrized models (main and epistatic effects) without using model-selection methods. Genetic control of GLS resistance was predominantly additive, with insignificant influence of dominance and epistasis effects.

Human insulin allergy-immediate and late type III reactions in a long-standing IDDM patient.

UNLABELLED: Human insulin allergy-immediate or late type III reaction-is a rare event. We report the case of a 33-year-old female patient with insulin-dependent diabetes mellitus for 25 years who presented, in the last 8 years, mild but generalized urticaria partially controlled with oral antihistamines. There was no improvement after changing from mixed beef-pork to human insulin. In the last 3 years another allergic manifestation began: small, localized, subdermal and painful non-erythematous nodules with central hematomas at injection sites, occurring 6-8 h after the insulin injection and lasting for 48 h. The following maneuvers had no benefit: (1) Human insulin (NPH or Lente) administered with dexametasone or xylocain locally, (2) Short acting human insulin with or without previous boiling, (3) Anti-histamine cetirizine dihydrochloride-10 mg/day. The allergic symptoms disappeared only after treatment with short acting human insulin (up to 100 U/day) associated to prednisone-40 mg/day and cetirizine dihydrochloride for 4 months. However, after stopping prednisone the urticaria reappeared and it was relieved with insulin desensitization. The pain at the site of injections persisted. CONCLUSION: This long-standing IDDM patient presented two types of reactions to human insulin: the immediate type (systemic urticaria), treated with antihistamines and desensitization, and the Arthus' type III reaction (nodules and hematomas occurring 6-8 h after the insulin injection) that required glucocorticoid therapy for more than 4 months.

[The sensitivity and specificity of the ergometric test for the diagnosis of coronary disease]. / Sensibilidade e especificidade do teste ergométrico para o diagnóstico da doença coronária.

According to the principles of probabilistic analysis, sensitivity and specificity of a diagnostic test are fixed values. Nevertheless, most authors consider them to be inconstant values, specially when applied to the diagnosis of coronary heart disease by exercise stress test. In this paper, we review the basic concepts on sensitivity and specificity of diagnostic tests and try to explain their supposed variability, when related to exercise test, as a function of undue comparison between ST-segment response and the findings of cinecoronariography. Based on the essential difference between coronary heart disease and ischemic heart disease, we demonstrate why such an equivocal comparison can lead to false results of sensitivity and specificity of exercise tests relative to coronary heart disease. As a result, their alleged variability depends most on the prevalence of ischemia throughout the spectrum of coronary heart disease in the studied population. As a matter of fact, unless one can rely on a method as a gold standard for the diagnosis of ischemic heart disease, the real sensitivity and specificity of exercise stress test should be considered as unknown values.