Discovery of a Necroptosis Inhibitor Improving Dopaminergic Neuronal Loss after MPTP Exposure in Mice.

Parkinson's disease (PD) is the second most common neurodegenerative disorder, mainly characterized by motor deficits correlated with progressive dopaminergic neuronal loss in the substantia nigra pars compacta (SN). Necroptosis is a caspase-independent form of regulated cell death mediated by the concerted action of receptor-interacting protein 3 (RIP3) and the pseudokinase mixed lineage domain-like protein (MLKL). It is also usually dependent on RIP1 kinase activity, influenced by further cellular clues. Importantly, necroptosis appears to be strongly linked to several neurodegenerative diseases, including PD. Here, we aimed at identifying novel chemical inhibitors of necroptosis in a PD-mimicking model, by conducting a two-step screening. Firstly, we phenotypically screened a library of 31 small molecules using a cellular model of necroptosis and, thereafter, the hit compound effect was validated in vivo in a sub-acute 1-methyl-1-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP) PD-related mouse model. From the initial compounds, we identified one hit-Oxa12-that strongly inhibited necroptosis induced by the pan-caspase inhibitor zVAD-fmk in the BV2 murine microglia cell line. More importantly, mice exposed to MPTP and further treated with Oxa12 showed protection against MPTP-induced dopaminergic neuronal loss in the SN and striatum. In conclusion, we identified Oxa12 as a hit compound that represents a new chemotype to tackle necroptosis. Oxa12 displays in vivo effects, making this compound a drug candidate for further optimization to attenuate PD pathogenesis.

Differential reactivity of serum immunoglobulins from Brazilian wild mammals to staphylococcal A and streptococcal G proteins.

Human pathogens have evolved to infect vertebrate hosts other than human beings without causing symptoms of the disease, thus permitting them to complete their life cycle and to develop into infectious forms. The identification and management of infected animals are alternatives to control dissemination of the disease and to prevent human illness. In the current study, the potential use of staphylococcal A or streptococcal G proteins was evaluated with enzyme-linked immunosorbent assays (ELISAs) for seroepidemiological studies. Sera were collected from animals that were representative of 23 different Brazilian wild mammals. A high protein A binding rate was observed in all animals, except for the orders Didelphimorphia, Artiodactyla, and Rodentia, in which affinity was medium or low. Affinity for streptococcal G protein was higher in animals of the order Artiodactyla, whereas no streptococcal G protein binding was observed in samples obtained from felines (order Carnivora). Bacterial protein binding to mammalian immunoglobulins was confirmed by immunoblotting. The results suggest that secondary detection systems should be better investigated in ELISA protocols before their implementation in seroepidemiological studies involving wild mammals.

Effects of food pattern change and physical exercise on cafeteria diet-induced obesity in female rats.

Obesity affects a large number of people around the world and appears to be the result of changes in food intake, eating habits and physical activity levels. Changes in dietary patterns and physical exercise are therefore strongly recommended to treat obesity and its complications. The present study tested the hypothesis that obesity and metabolic changes produced by a cafeteria diet can be prevented with dietary changes and/or physical exercise. A total of fifty-six female Wistar rats underwent one of five treatments: chow diet; cafeteria diet; cafeteria diet followed by a chow diet; cafeteria diet plus exercise; cafeteria diet followed by a chow diet plus exercise. The duration of the experiment was 34 weeks. The cafeteria diet resulted in higher energy intake, weight gain, increased visceral adipose tissue and liver weight, and insulin resistance. The cafeteria diet followed by the chow diet resulted in energy intake, body weight, visceral adipose tissue and liver weight and insulin sensitivity equal to that of the controls. Exercise increased total energy intake at week 34, but produced no changes in the animals' body weight or adipose tissue mass. However, insulin sensitivity in animals subjected to exercise and the diet was similar to that of the controls. The present study found that exposure to palatable food caused obesity and insulin resistance and a diet change was sufficient to prevent cafeteria diet-induced obesity and to maintain insulin sensitivity at normal levels. In addition, exercise resulted in normal insulin sensitivity in obese rats. These results may help to develop new approaches for the treatment of obesity and type 2 diabetes mellitus.

Antibiotic prophylaxis in cholecystectomies in a teaching hospital in Brazil.

BACKGROUND: Medical literature reports that adequate prophylaxis with antibiotics can reduce the incidence of postoperative infections. OBJECTIVE: To investigate the impact of adopting multiple practices for improving the rational use of antibiotic prophylaxis in patients undergoing cholecystectomy and evaluate, during 2 periods, compliance with the hospital Drug Committee's recommendation and guidelines published in the medical literature. METHODS: Data were collected from patients' medical records at the Hospital de Clínicas de Porto Alegre (HCPA), Brazil, in 2003. We evaluated 222 procedures as set by guidelines published in the literature and the hospital's recommendation. RESULTS: In 24.5% of the cases, the choice of whether to use the prophylactic antibiotic was not made according to the guidelines. The choice of the antibiotic agent, prophylaxis duration, dose administered, and time for administration was appropriate in 95%, 80.5%, 100%, and 81.8% of cases, respectively. A significant improvement in guideline compliance was observed since multiple practices were adopted to improve the rational use of antibiotic prophylaxis. CONCLUSIONS: Compliance with the guidelines for antibiotic prophylaxis for cholecystectomy, in combination with a greater integration among the professionals involved in the HCPA Infection Control Service, resulted in a more appropriate use of these prophylactic agents. Improving physicians' awareness of the importance of meeting guidelines is critical and will benefit patients and the hospital as a whole.

Prescribing practice for antibiotic prophylaxis for cesarean section in a teaching hospital in Brazil.

BACKGROUND: The contribution of antibiotic prophylaxis to reduce surgical wound infection and endometritis after cesarean section is well-known. Despite the knowledge about the effectiveness of antibiotic prophylaxis with this procedure, the administrative regimens are often inappropriate. METHODS: The use of antibiotic prophylaxis in cesarean section was evaluated in a reference school hospital. Data were collected from medical records, and they correspond to the 9-month observation during 1995 and 1996. RESULTS: The cesarean section rate was 26.4% in this period. The total procedures observed was 587. Antibiotic prophylaxis was prescribed in 358 procedures (61%). Cephalothin was the most prescribed drug (98.6%), with a regimen of 2 g intravenously after clamping of the umbilical cord and 2 more doses of 1g every 6 hours. Antibiotic prophylaxis was indicated more frequently in patients younger than 30 years and in those with rupture of membranes for more than 6 hours; such differences were significant (P <.05 and P <.00001, respectively). CONCLUSION: The prescribers met the hospital guidelines for antibiotic prophylaxis in only 37.1% of the cesarean sections performed.

Evidence that similar neurotransmitter mechanisms in amygdala, hippocampus and medial septum regulate memory consolidation of avoidance behavior in rats

A injeçäo de ácido DL-amino-5-fosfonopentanóico (AP5) ou escopolamina na amígdala, no septo medial ou no hipocampo, imediatamente após o treino, causa amnésia retrógrada para um aprendizado de esquiva inibitória em ratos. A picrotoxina, no entanto, causa facilitaçäo retrógrada da memória e bloqueia o efeito do AP5 e da escopolamina. O timolol näo tem efeito próprio mas cancela as açöes da picrotoxina. O AP5 é um antagonista de receptores a N-metil-D- aspartato (NMDA) dos aminoácidos excitatórios; a escopolamina é um antagonista dos receptores colinérgicos muscarínicos; a picrotoxina bloqueia o canal de cloro estimulado pelos receptores GABA-A; e o timolol é um antagonista dos ß adrenoreceptores. Os resultados indicam que, na amígdala, no septo medial e no hipocampo, receptores NMDA e muscarínicos säo necessários para a consolidaçäo da memória, receptores GABA-A inibem a açäo dos anteriores, e receptores ß noradrenérgicos modulam a açäo dos receptores GABA-A. A amígdala, o septo medial e o hipocampo operam de forma näo redundante na consolidaçäo da memória