Are isomeric alkenes used in species recognition among neo-tropical stingless bees (Melipona spp)

The majority of our understanding of the role of cuticular hydrocarbons (CHC) in recognition is based largely on temperate ant species and honey bees. The stingless bees remain relatively poorly studied, despite being the largest group of eusocial bees, comprising more than 400 species in some 60 genera. The Meliponini and Apini diverged between 80-130 Myr B.P. so the evolutionary trajectories that shaped the chemical communication systems in ants, honeybees and stingless bees may be very different. Therefore, the main aim of this study was to study if a unique species CHC signal existed in Neotropical stingless bees, as shown for many temperate species, and if so what compounds are involved. This was achieved by collecting CHC data from 24 colonies belonging to six species of Melipona from North-eastern Brazil and comparing this new data with all previously published CHC studies on Melipona. We found that each of the eleven Melipona species studied so far each produced a unique species CHC signal based around their alkene isomer production. A remarkable number of alkene isomers, up to 25 in M. asilvai, indicated the diversification of alkene positional isomers among the stingless bees. The only other group to have really diversified in alkene isomer production are the primitively eusocial Bumblebees (Bombus spp), which are the sister group of the stingless bees. Furthermore, among the eleven Neotropical Melipona species we could detect no effect of the environment on the proportion of alkane production as has been suggested for some other species

Evaluation of a protocol for coronary artery disease investigation in asymptomatic elderly hemodialysis patients

Jose Jayme G De Lima,1 Luis Henrique W Gowdak,1 Flavio J de Paula,1 Henrique Cotchi S Muela,2 Elias David-Neto,1 Luiz A Bortolotto1 1Heart Institute (InCor) and Renal Transplant Unit, Division of Urology, Hospital das Clínicas, University of São Paulo Medical School, São Paulo, SP, Brazil; 2Department of Medicine, Agostinho Neto University Medical School, Luanda, Angola Background: Coronary artery disease (CAD) is prevalent in older patients on dialysis, but the prognostic relevance of coronary assessment in asymptomatic subjects remains undefined. We tested the usefulness of a protocol, based on clinical, invasive, and noninvasive coronary assessment, by answering these questions: Could selecting asymptomatic patients for coronary invasive assessment identify those at higher risk of events? Is CAD associated with a worse prognosis?Methods: A retrospective study including 276 asymptomatic patients at least 65 years old on the waiting list, prospectively evaluated for CAD and followed up until death or renal transplantation, were classified into two groups: 1) low-risk patients who did not undergo coronary angiography (n=63) and 2) patients who did undergo angiography (n=213). The latter group was reclassified into patients with significant CAD or normal angiograms/nonsignificant CAD.Results: CAD (≥70% stenosis) occurred in 124 subjects (58%). The incidence of death by any cause, coronary death, and major cardiovascular (CV) events were similar in patients selected or not for angiography and in those with or without significant CAD. Myocardial revascularization (surgical/percutaneous) was performed in only 21/276 patients (7.6%) and did not result in a reduction in mortality.Conclusion: In older patients on renal replacement therapy, the prevalence of CAD was high, but coronary investigation was not useful as a risk stratification tool and also resulted in a rather small proportion of patients eligible for intervention. Therefore, in the elderly, coronary investigation should not be considered routine in asymptomatic patients. Keywords: elderly, hemodialysis, coronary artery disease, kidney transplantation, cardiovascular, chronic kidney diseas

Human leukocyte antigens and malignant essential hypertension

The purpose of this study was to investigate an association between human leukocyte antigens (HLA) and the susceptibility to malignant hypertension. the presence of HLA-A -B, -DR, and -DQ was determined in 33 white and in 23 mulatto Brazilian patients with malignant essential hypertension. No statistically significant differences were detected between patients and control subjects. It is nevertheless important to note that we have observed an increased frequency of DR3 in the mulatto patients (34.8% v 21.4%). We consider that this finding supports the existence of an HLA-DR3 association with hypertension in the black population, as has been claimed by other authors. (C) 1998 American Journal of Hypertension, Ltd.Universidade Federal de São Paulo, Escola Paulista Med, São Paulo, BrazilUniversidade Federal de São Paulo, Inst Coracao, Hosp Clin, Fac Med, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, São Paulo, BrazilUniversidade Federal de São Paulo, Inst Coracao, Hosp Clin, Fac Med, São Paulo, BrazilWeb of Scienc