Short-term exposure to dexamethasone promotes autonomic imbalance to the heart before hypertension

Hypertension is one of the chronic side effects of dexamethasone (DEX) treatment; however, almost nothing is known about its acute effects. Therefore, the aim of this study was to investigate the possible mechanisms involved in blood pressure control after acute or short-term DEX treatment in adult animals. Eighty Wistar rats were divided into four groups: C1 and C5, for rats treated with saline for 1 or 5 days, respectively; D1 and D5, for rats treated with DEX for 1 or 5 days, respectively (decadron, 1 mg/kg, i.p.). Heart rate was increased in DEX treatment, but arterial pressure and cardiac muscle mass were not altered. Only few and isolated changes on gene expression and protein level of renin-angiotensin system components were observed. Five days of DEX treatment, but not one day, determined an increase in sympathetic component of spectral analysis (+75.93%, P < .05) and a significant reduction of parasympathetic component (–18.02%, P < .05), which contributed to the autonomic imbalance to the heart (LF/HF, +863.69%). The results of this present study demonstrated, for the first time, that short-term exposure to DEX treatment impairs the autonomic balance to the heart before hypertension, which was independent of renin-angiotensin system.     

Covid-19 post-infectious acute transverse myelitis responsive to corticosteroid therapy: report of two clinical cases

Journal of NeuroVirology - SARS-COV-2 infection has affected millions of individuals with a wide range of clinical manifestations, including central and peripheral nervous systems through several...     

Understanding the HER family in breast cancer: interaction with ligands,dimerization and treatments

Barros F F T, Powe D G, Ellis I O & Green A R
(2010) Histopathology 56 , 560–572 Understanding the HER family in breast cancer: interaction with ligands, dimerization and treatments Breast carcinoma is the most frequent type of cancer affecting women. Among the recently described molecular and phenotypic classes of breast cancer, human epidermal growth factor receptor 2 (HER2)‐positive tumours are associated with a poor prognosis. HER2 plays an important role in cancer progression being targeted to provide predictive and prognostic information. Moreover, HER2 is related to cancer resistance against a variety of therapies; however, trastuzumab (herceptin) has proved successful in treatment of this subgroup. Nevertheless, resistance to this drug may be acquired by patients after a period of treatment, which indicates that other molecular mechanisms might influence success of this therapy. Dimerization between members of the HER family may contribute to resistance against treatments due to different combinations that trigger different downstream pathways. This is promoted by ligands, which are expressed as transmembrane precursor protein molecules and have a conserved epidermal growth factor‐like domain. Through resistance to trastuzumab, other drugs are being developed to interact in different domains of HER2 protein. It might be a good strategy to apply new drugs simultaneously to trastuzumab due to act in different domains of HER2. The study of interaction between receptors/ligands will characterize specifically their signalling pathway and understand which strategy to acquire.     

Evaluation of three Brazilian antivenom ability to antagonize myonecrosis and hemorrhage induced by Bothrops snake venoms in a mouse model.

Despite preventing death after snakebites, there is little evidence that polyvalent antivenoms (PAVs) protect against myotoxicity and local damages. We evaluated antibothropic Brazilian PAVs from three manufacturers against the myotoxicity and hemorrhagic activity of Bothrops jararacussu and B. jararaca venoms, respectively, by using two protocols: preincubation of PAVs with venom, and i.v. pretreatment with PAVs, prior to the venom inoculation. In this investigation, we used doses of PAVs ranging from 0.4 to 4.0mL/mg of venom equivalent up to 10 times the amount recommended by the producers for the clinical practice in Brazil. In our preincubation protocol in vivo, PAVs antagonized myotoxicity of B. jararacussu venom by 40-95%, while our pretreatment protocol antagonized myotoxic activity by 0-60%. Preincubation of antivenoms with B. jararaca venom antagonized its hemorrhagic activity by 70-95%, while pretreatment antagonized hemorrhagic activity by 10-50%. Although all PAVs demonstrated partial antagonism against both venoms, the magnitude of these effects varied greatly among the manufactures. The results suggest that the current clinical doses of these PAVs may have negligible antimyotoxic effect.     

Human bocavirus infection in children with gastroenteritis, Brazil

Human bocavirus (HBoV) was detected in 14 (2%) of 705 fecal specimens from Brazilian children with gastroenteritis. Coinfection with rotavirus, adenovirus, or norovirus was found in 3 (21.4%) HBoV-positive specimens. None of the HBoV-positive patients had respiratory symptoms.