Chronic Stress Improves NO- and Ca2+ Flux-Dependent Vascular Function: A Pharmacological Study

Background: Stress is associated with cardiovascular diseases. Objective: This study aimed at assessing whether chronic stress induces vascular alterations, and whether these modulations are nitric oxide (NO) and Ca2+ dependent. Methods: Wistar rats, 30 days of age, were separated into 2 groups: control (C) and Stress (St). Chronic stress consisted of immobilization for 1 hour/day, 5 days/week, 15 weeks. Systolic blood pressure was assessed. Vascular studies on aortic rings were performed. Concentration-effect curves were built for noradrenaline, in the presence of L-NAME or prazosin, acetylcholine, sodium nitroprusside and KCl. In addition, Ca2+ flux was also evaluated. Results: Chronic stress induced hypertension, decreased the vascular response to KCl and to noradrenaline, and increased the vascular response to acetylcholine. L-NAME blunted the difference observed in noradrenaline curves. Furthermore, contractile response to Ca2+ was decreased in the aorta of stressed rats. Conclusion: Our data suggest that the vascular response to chronic stress is an adaptation to its deleterious effects, such as hypertension. In addition, this adaptation is NO- and Ca2+-dependent. These data help to clarify the contribution of stress to cardiovascular abnormalities. However, further studies are necessary to better elucidate the mechanisms involved in the cardiovascular dysfunction associated with stressors. (Arq Bras Cardiol. 2014; [online].ahead print, PP.0-0)

Dipyridamole stress myocardial perfusion by computed tomography in patients with left bundle branch block

Abstract Background: Functional tests have limited accuracy for identifying myocardial ischemia in patients with left bundle branch block (LBBB). Objective: To assess the diagnostic accuracy of dipyridamole-stress myocardial computed tomography perfusion (CTP) by 320-detector CT in patients with LBBB using invasive quantitative coronary angiography (QCA) (stenosis ≥ 70%) as reference; to investigate the advantage of adding CTP to coronary computed tomography angiography (CTA) and compare the results with those of single photon emission computed tomography (SPECT) myocardial perfusion scintigraphy. Methods: Thirty patients with LBBB who had undergone SPECT for the investigation of coronary artery disease were referred for stress tomography. Independent examiners performed per-patient and per-coronary territory assessments. All patients gave written informed consent to participate in the study that was approved by the institution’s ethics committee. Results: The patients’ mean age was 62 ± 10 years. The mean dose of radiation for the tomography protocol was 9.3 ± 4.6 mSv. With regard to CTP, the per-patient values for sensitivity, specificity, positive and negative predictive values, and accuracy were 86%, 81%, 80%, 87%, and 83%, respectively (p = 0.001). The per-territory values were 63%, 86%, 65%, 84%, and 79%, respectively (p < 0.001). In both analyses, the addition of CTP to CTA achieved higher diagnostic accuracy for detecting myocardial ischemia than SPECT (p < 0.001). Conclusion: The use of the stress tomography protocol is feasible and has good diagnostic accuracy for assessing myocardial ischemia in patients with LBBB.

Soluble ST2 Testing: A Promising Biomarker in the Management of Heart Failure

Abstract ST2 is a member of the interleukin-1 receptor family biomarker and circulating soluble ST2 concentrations are believed to reflect cardiovascular stress and fibrosis. Recent studies have demonstrated soluble ST2 to be a strong predictor of cardiovascular outcomes in both chronic and acute heart failure. It is a new biomarker that meets all required criteria for a useful biomarker. Of note, it adds information to natriuretic peptides (NPs) and some studies have shown it is even superior in terms of risk stratification. Since the introduction of NPs, this has been the most promising biomarker in the field of heart failure and might be particularly useful as therapy guide.

Analysis of phenotypes altered by temperature stress and hipermutability in Drosophila willistoni

Drosophila willistoni (Sturtevant, 1916) is a species of the willistoni group of Drosophila having wide distribution from the South of USA (Florida) and Mexico to the North of Argentina. It has been subject of many evolutionary studies within the group, due to its considerable ability to successfully occupy a wide range of environments and also because of its great genetic variability expressed by different markers. The D. willistoni 17A2 strain was collected in 1991 in the state of Rio Grande do Sul, Brazil (30°05'S, 51°39'W), and has been maintained since then at the Drosophila laboratory of UFRGS. Different to the other D. willistoni strains maintained in the laboratory, the 17A2 strain spontaneously produced mutant males white-like (white eyes) and sepia-like (brown eyes) in stocks held at 17°C. In order to discover if this strain is potentially hypermutable, we submitted it to temperature stress tests. Eighteen isofemale strains were used in our tests and, after the first generation, all the individuals produced in each strain were maintained at 29°C. Different phenotype alterations were observed in subsequent generations, similar to mutations already well characterized in D. melanogaster (white, sepia, blistered and curly). In addition, an uncommon phenotype alteration with an apparent fusion of the antennae was observed, but only in the isofemale line nº 31. This last alteration has not been previously described as a mutation in the D. melanogaster species. Our results indicate that the D. willistoni 17A2 strain is a candidate for hypermutability, which presents considerable cryptic genetic variability. Different factors may be operating for the formation of this effect, such as the mobilization of transposable elements, effect of inbreeding and alteration of the heat-shock proteins functions.

The vitellogenin gene family of Aedes aegypti

We have been interested in identifying genes that play a role in reproduction of the mosquito Aedes aegypti. Our interests are currently focused on the vitellogenin genes which in the mosquito are expressed only in the fat body in response to the insect steroid hormone, 20-hydroxyecdysone. Four of the five vitellogenin genes in the genome have been cloned. We have examined the relationships between these genes and find that they form a small gene family exhibiting different levels of relationship.

From a mono to a digenetic life-cycle: how was the jump for flagellates of the family trypanosomatidae?

It has been found that species of the digenetic genus Trypanosoma as well as species of monogenetic trypanosomatids of insects can grow in the lumen of the scent glands of opossums reproducing the cycle they perform in the intestinal tract of their insect hosts. Based on these findings, speculations are made on the incompletely known cycles of many mammalian trypanosomes and on the evolution of the family Trypanosomatidae.

Screening of the antimalarial activity of plants of the Cucurbitaceae family

Crude ethanolic extracts (CEEs) from two species of Cucurbitaceae, Cucurbita maxima and Momordica charantia (commonly called "abóbora moranga" and melão de São Caetano", respectively) were assayed for antimalarial activity by the 4-d suppressive test. The CEE of dry C. maxima seeds showed strong antimalarial activity following oral administration (259 and 500 mg/kg), reducing by 50% the levels of parasistemia in Plasmodium berghey-infected mice. Treatment of normal animals with 500 mg/Kg of the extract three days before intravenous injection of P. berghei caused a significant 30% reduction in parasitemic levels. No effect was observed when the animals were treated with the CEE only on the day of inoculation. Oral administration of the CEE of dry M. charantia leaves adminstered orally was ineffective up to 500 mg/Kg in lowering the parasitemic levels of malarious mice.

On some family related parasites (Nematoda, Cucullanidae) from the marine fish Paralonchurus brasiliensis (Steindachner, 1875) (Pisces, Ostraciidae)

Dichelyne (Cucullanellus) elongatus (Tornquist, 1931) Petter, 1974 and Cucullanus pulcherrimus Barreto, 1918, from Paralonchurus brasiliensis (Steind., 1875) are redescribed and two specimens of Dichelyne (Cucullanellus) sp. are also reported in this host, despite lack of previously, was again identified in Brazil since its original description and posterior illustration. The present findings represent also a new host record for the referred genera: Dichelyne Jagerskiold, 1902 and Cucullanus Mueller, 1777. D. (C.) elongatus is also referred in Brazil for the first time.

Re-description of Trypanosoma corvi Stephens and Christophers,1908 Emend. Baker, 1976 and remarks on the Trypanosomes of the Avian Family Corvidae

The trypomastigote, epimastigote and amastigote stages of Trypanosoma corvi Stephens and Christophers, 1908 emend. Baker, 1976 from the peripheral blood, heart and bone marrow are described herein. Other trypanosomes described from the Corvidae are compared to T. corvi and their status is discussed.

Thevetia peruviana (Family: Apocynaceae) in the control of slug and snail pests

An aqueous extract prepared from Kernels of the fruit of Thevetia peruviana (Pers.) Schumann (Family : Apocynaceae) was found under experimental conditions, to be toxic ti the slug Laevicaulis alte (Férussac) and the snail Achatina fulica Bowdich, the important agrihorticultural pests of Indo-Pacific countries. Concentrations as low as 1% (w/v) killed all the slugs exposed in less than 981.00 (± SD 22.76) min, and 2% of the extract killed 100% of the slugs L. alte and 50%, 50% and 30% of the snail A. fulica in between 92.34 (± SD 6.63) - 321.33 (± SD 4.14) and 271.20 (± SD 17.54) - 298.26 (± SD 16.69) min respectively. The most effective concentration of the extract was 20%; it killed 100% of exposed slugs and snails within a short time (40-50 and 90-1440 min respectively) when the extract was exposed on the soil in experimental trays or when it was applied to potato slices offered as food to the gastropods.

Aspects of immunity for the AMA-1 family of molecules in humans and non-human primates malarias

The apical membrane antigen (AMA-1) family of malaria merozoite proteins is characterised by a high degree of inter-species conservation. Evidence that the protein (PK66/AMA-1) from the simian parasite Plasmodium knowlesi was protective in rhesus monkeys suggested that the 83kDa P. falciparum equivalent (PF83/AMA-1) should be investigated for protective effects in humans. Here we briefly review pertinent comparative data, and describe the use of an eukaryotic full length recombinant PF83/AMA-1 molecule to develop a sensitive ELISA for the determination of serological responses in endemic populations. The assay has revealed surprisingly high levels of humoral response to this quantitatively minor antigen. We also show that PK66/AMA-1 inhibitory mAb's are active against merozoites subsequent to release from schizont-infected red cells, further implicating AMA-1 molecules in red cell invasion.

Prevalence and factors associated to the epidemic neuropathy in a population assisted by a family doctor in Cuba

With the outbreak of an epidemic neuropathy (EN) of unknown ethiology, a study of the prevalence and factors associated to the disease was carried out in the Zamora community, municipality of Marianao, Havana City. There were 11 patients identified with EN for a prevalence rate of 1.7/100. The major risk group was the one between 45 and 64 years of age, female sex, black skin. In the univaried analysis, a high prevalence ratio (PR) was found linked to beverage intake (PR=5.32 95%; confidence intervals (CI) = 1.2-24.4), frequent drugs intake (PR=6.59; CI=1.8-24.6), consumption of edible of non certified fats (PR=4.48; CI=1.2-16.7) and the smoking habit (PR=3.6; CI=1.1-12.2). More than73/100 (CI= 68.7-78.3) of the people under serologic study were infected with Coxsakie virus A-9 (strain 47) isolated from a patient still under research. It seems there are many factors like linder intake, antecedents of hemorrhagic conjuntivitis, nutritional aspects and others that, with the virus isolated were associated with this epidemiologic situation.