Changes in sensitivity of the isolated guinea-pig vas deferens induced by a lyophilized Phoradendron latifolium leaf infusion

The effect of a lyophilized mistletoe infusion (LMI) was studied on isolated guinea-pig vas deferens. LMI caused a contraction which was partially blocked by phentolamine but not by atropine. LMI caused a shift to the left of the norepinephrine concentration-effect curve (CEC), an effect which appeared to be blocked by atropine and was absent in animals previously treated with reserpine and α-methyl-para-tyrosine. The increase of the norepinephrine maximal response induced by LMI was not blocked by atropine or pharmacological denervation. LMI caused a shift to the right of the acetylcholine CEC and had no effect on the acetylcholine maximal response. These results suggest that the effects seem to be due mainly to the presence of potassium ion in the LMI; however, the participation of muscarinic agonist(s) of reduced intrinsic activity or some tyramine-like substance could not be ruled out.

Influence of the estrous cycle on the sensitivity to catecholamines in right atria from rats submitted to foot-shock stress

We investigated the mechanisms of the alterations in sensitivity to catecholamines in right atria from female rats exhibiting regular 4-day estrous cycles after three foot-shock sessions at estrus, metestrus, and diestrus or at diestrus, proestrus, and estrus. Right atria from stressed rats sacrificed at diestrus showed subsensitivity to noradrenaline and adrenaline. After in vitro sympathetic denervation (38 μM 6-hydroxydopamine) plus inhibition of neuronal reuptake (0.1 μM desipramine) subsensitivity to noradrenaline was abolished, but it was again evident when extraneuronal uptake was also inhibited (10 μM phenoxybenzamine and 30 μM corticosterone). The same pretreatment abolished the subsensitivity to adrenaline. After addition of 1 μM butoxamine, a β2-adrenoceptor antagonist, the tissues from stressed rats were subsensitive to adrenaline. Right atria from stressed rats sacrificed at estrus did not show any alteration in sensitivity to catecholamines. We conclude that after foot-shock stress, right atria from female rats sacrificed at diestrus showed subsensitivity of the chronotropic response to catecholamines as a result of a conformational alteration of β1-adrenoceptors, simultaneously with an increase in β2-adrenoceptor-mediated response. The mechanisms seem to be similar to those which underlie stress-induced alterations in catecholamine sensitivity in right atria from male rats. However, during estrus there are some protective factors that prevent the effects of stress on right atria.

Characteristics of Yersinia pseudotuberculosis isolated from animals in Brazil

Strains (105) of Yersinia pseudotuberculosis isolated in Brazil between 1982 and 1990 mere bio-serotyped. They were also studied for plasmid profile, autoagglutination and calcium dependence at 37 degrees C, Congo red uptake, pyrazinamidase activity, esculin hydrolysis, salicin fermentation and drug sensitivity: 95.24% were biotype 2, serogroup O:3; 2.86% were biotype 1, serogroup O:1; and 1.90% were biotype 2, non-agglutinable. Plasmids were found in 77.14% of the strains (one in each strain). There was total correlation between the presence of the virulence plasmid and autoagglutination, calcium dependence at 37 degrees C and Congo red uptake. The esculin, salicin and pyrazinamidase tests were not efficient in differentiating pathogenic from non-pathogenic Y, pseudotuberculosis isolates. All strains were highly sensitive to the drugs used. These results indicate that Y. pseudotuberculosis is a potential pathogen for humans in Brazil, especially because the bio-serogroups detected among animals are those most frequently associated with human diseases.

Mastite subclínica causada por Staphylococcus aureus: Custo-benefício da antibioticoterapia de vacas em lactação

Economic evaluation of the treatment bovine subclinical mastitis caused by S. aureus was evaluated. Two hundred and seventy udder quarters with or without subclinical mastitis were distributed into four groups, in conformity to lactational stage and treatments. Group 1 included animals treated between 10 and 60 days of lactation; group 2 included animals treated from 61 days of lactation to two months before drying; group 3 included animals no treated between 10 and 60 days of lactation; group 4 included animals no treated from 61 days of lactation to two months before drying. Treatment with gentamicin (150mg) was accomplished by intramammary doses, once a day, after performing sensitivity tests. The mammary quarters were re-evaluated after 30 days. The costs with the treatment were calculated considering a S. aureus prevalence of 5% as well as expenses with antibiotic, milk disposal, tests of drug sensitivity and workload. There was loss of income of 2% and 14% in the groups 1 and 2, respectively, when compared with the values before the treatment. In such case, the treatment of bovine subclinical mastitis caused by S. aureus in the lactation was economically unviable.

Detecção da produção de slime por estafilococos coagulase-negativa isolados de cateter venoso central

Slime production is an important virulence factor of coagulase-negative Staphylococcus spp., allowing them to attach to smooth surfaces of biomaterials, and it has been associated with infections of implanted medical devices. In the present study the production of slime capsules in 27 strains of coagulase-negative Staphylococcus was investigated by culture in Congo Red agar (77.7% positivity), spectrophotometric or microplate method (81.4% positivity) and scanning electron microscopy (88.9% positivity). The resistance of coagulase-negative strains of Staphylococcus to various antimicrobial agents was also determined by agar disk diffusion. The proportion of strains resistant to penicillin G, oxacillin, erythromycin, clindamycin and gentamicin among the slime-producing staphylococci was 88.9%, 70.4%, 81.5%, 66.7% and 59.2%, respectively; all of the coagulase-negative staphylococci were susceptible to vancomycin. The strains isolated from central venous catheters were identified by a conventional method and the API Staph system. The 27 coagulase-negative Staphylococcus strains were identified as: S. saprophyticus (3.7%), S. xylosus (7.4%), S. haemolyticus (14.8%), S. epidermidis (37.0%), S. warneri (14.8%), S. lugdunensis (7.4%), S. hominis (7.4%), S. schleiferi (3.7%) and S. chromogenes (3.7%). It can be concluded that in the most of the coagulase-negative Staphylococcus species there was an association between slime production, the nosocomial origin of the strains and reduced sensitivity to the antibiotics, suggesting a pathogenic potential in the hospital environment.

Usefulness of Mycobacterium tuberculosis molecular typing in a tuberculosis low-endemic agro-industrial setting of Brazil

To highlight the transmission and major phylogenetic clades of Mycobacterium tuberculosis, a retrospective study was carried out at two health facilities in a small agro-industrial area in São Paulo, Brazil, that has a low tuberculosis incidence rate. IS6110-RFLP and spoligotyping were performed on the isolates, with the former revealing that 31.3% (35/112) of strains were clustered. Epidemiological links were found in 16 of the 35 clustered patients and were associated with transmission among patients living in public housing. Spoligotyping grouped 62.8% of the strains. The T genetic family predominated among the isolates. Of interest is that five strains had a pattern characteristic of African or Asian origin (ST535), and two others were of the rare localized type ST1888 (BRA, VEN). In addition, three new types-1889, 1890, and 1891-were identified. Spoligotyping showed that some ST may be circulating to or from Brazil, and RFLP revealed ongoing transmission in inadequately ventilated public-housing buildings. This may point to a failure in tuberculosis control policy.

Immunomodulatory effects of low dose chemotherapy and perspectives of its combination with immunotherapy

Given that cancer is one of the main causes of death worldwide, many efforts have been directed toward discovering new treatments and approaches to cure or control this group of diseases. Chemotherapy is the main treatment for cancer; however, a conventional schedule based on maximum tolerated dose (MTD) shows several side effects and frequently allows the development of drug resistance. On the other side, low dose chemotherapy involves antiangiogenic and immunomodulatory processes that help host to fight against tumor cells, with lower grade of side effects. In this review, we present evidence that metronomic chemotherapy, based on the frequent administration of low or intermediate doses of chemotherapeutics, can be better than or as efficient as MTD. Finally, we present some data indicating that noncytotoxic concentrations of antineoplastic agents are able to both up-regulate the immune system and increase the susceptibility of tumor cells to cytotoxic T lymphocytes. Taken together, data from the literature provides us with sufficient evidence that low concentrations of selected chemotherapeutic agents, rather than conventional high doses, should be evaluated in combination with immunotherapy. Copyright © 2012 UICC.

Ethopharmacological analysis of the open elevated plus-maze in mice

Exposure of rodents to an open elevated plus-maze (oEPM) elicits antinociception and increases plasma corticosterone levels. However, no studies have yet assessed the defensive behaviour repertoire of animals in this modified test. In Experiment 1, factor analysis was employed to characterise the behavioural profile of mice exposed to the oEPM. Experiments 2 and 3 assessed the effects of acute alprazolam (0.5-1.5. mg/kg; diazepam 0.5-1.5. mg/kg), pentylenetetrazole (10.0-30.0. mg/kg), yohimbine (2.0-6.0. mg/kg), mCPP (0.3-3.0. mg/kg), and acute and chronic fluoxetine (10.0-30.0. mg/kg) and imipramine (1.0-15.0. mg/kg) on behaviours identified in Experiment 1. The factor analyses revealed that behaviour in the oEPM can largely (77% total variance) be accounted for in terms of 3 factors: factor 1 ('. depth exploration'; e.g. head-dipping on the arms), factor 2 ('. cautious exploration of arms'; e.g. flatback approach), and factor 3 ('. risk assessment'; stretched attend postures - SAP). Experiments 2 and 3 showed that, over the dose range used, alprazolam selectively attenuated all measures of defensiveness. Similar, though more modest, effects were seen with diazepam. Confirming the intensity of the emotional response to the oEPM (nociceptive, endocrine and behavioural), relatively few significant behavioural changes were seen in response to the anxiogenic compounds tested. Although acute fluoxetine or imipramine treatment failed to modify behaviour in the oEPM, chronic fluoxetine (but not chronic imipramine) attenuated total flat back approach and increased head dipping outside the central square. Together, the results indicate that the oEPM induces behavioural defensive responses that are sensitive to alprazolam and chronic fluoxetine. © 2013 Elsevier B.V.

Systemic CA-MRSA infection following trauma during soccer match in inner Brazil: Clinical and molecular characterization

Even though community-acquired methicillin resistant Staphylococcus aureus (CA-MRSA) was described a decade ago, reports from Brazil are scarce and cases occurred in large urban centers. We report MRSA sepsis in a 16-year-old male from a small town and who had no history of exposure to healthcare or recent travel. After trauma during a soccer match, he presented swelling in the right thigh, which evolved in a month to cellulitis complicated by local abscess, orchitis and pneumonia. The patient presented severe sepsis, with fever and respiratory failure. Laboratory findings included blood leukocyte counts above 40,000/mm3 and thrombocytopenia. He was submitted to mechanical ventilation and therapy with vancomycin and imipenem. He had a slow but favorable response to therapy and was discharged after six weeks of hospitalization. MRSA grew from blood cultures and respiratory aspirates obtained before antimicrobial therapy. The isolate belonged to sequence type 5, spa type t311, harbored SCCmec type IV and genes for Panton-Valentine leukocidin and Enterotoxin A. The pulsed-field gel electrophoresis pattern was distinct from North American classic CA-MRSA clones. However, the sequence type and the spa type revealed that the clone belong to the same clonal complex isolated in Argentina. This is the first CA-MRSA infection reported in that region, with significant epidemiologic and clinical implications. © 2013 Elsevier Inc.