Comparison of three diagnostic techniques for the detection of leptospires in the kidneys of wild house mice (Mus musculus)

Forty-one wild house mice (Mus musculus) were trapped in an urban area, near railways, in Santa Fe city, Argentina. Both kidneys from each mouse were removed for bacteriological and histological examination. One kidney was inoculated into Fletcher semi-solid medium and isolates were serologically typed. The other kidney was microscopically examined after hematoxylin-eosin, silver impregnation and immunohistochemical stains. Leptospires, all of them belonging to the Ballum serogroup, were isolated from 16 (39%) out of 41 samples. The presence of the agent was recorded in 18 (44%) and in 19 (46%) out of 41 silver impregnated and immunohistochemically stained samples respectively. Additionally, leptospires were detected in high number on the apical surface of epithelial cells and in the lumen of medullary tubules and they were less frequently seen on the apical surface of epithelial cells or in the lumen of the cortical tubules, which represents an unusual finding in carrier animals. Microscopic lesions consisting of focal mononuclear interstitial nephritis, glomerular shrinkage and desquamation of tubular epithelial cells were observed in 13 of 19 infected and in 10 of 22 non-infected mice; differences in presence of lesions between infected and non-infected animals were not statistically significant (P=0,14). The three techniques, culture, silver impregnation and immunohistochemistry, had a high agreement (k³0.85) and no significant differences between them were detected (P>0.05). In addition, an unusual location of leptospires in kidneys of carrier animals was reported, but a relationship between lesions and presence of leptospires could not be established.

Screening of antigenemia and isolation of Cryptococcus neoformans and C. gattii from cloaca and crop of birds in the state of Paraná, Brazil

Cryptococcus neoformans and C. gattii are associated with dry bird excreta but rarely recovered from birds' digestive tract. The objective of the present study was (1) to verify the existence of C. neoformans and C. gattii in crop and cloaca of wildlife and captivity birds hypothesizing about a possible primary source of this yeast in the excreta, and (2) to determine the fungi's invasive capability in avian species through latex agglutination. For that purpose, 172 cloacal and 77 crop samples of domestic pigeon, Passerine, and Psittacine birds were collected. None of these samples was positive, suggesting that the yeast is not saprobiotic in the digestive tract of these birds. Only one out of 82 serum samples collected from pigeons and Psittacine birds was positive (title 1:2) showing that Cryptococcus sp. probably has a low invasive capability in birds, and is thus considered only a dry excreta colonizer.

Functional characterization and localization of AQP3 in the human colon

Water channels or aquaporins (AQPs) have been identified in a large variety of tissues. Nevertheless, their role in the human gastrointestinal tract, where their action is essential for the reabsorption and secretion of water and electrolytes, is still unclear. The purpose of the present study was to investigate the structure and function of water channels expressed in the human colon. A cDNA fragment of about 420 bp with a 98% identity to human AQP3 was amplified from human stomach, small intestine and colon by reverse transcription polymerase chain reaction (RT-PCR) and a transcript of 2.2 kb was expressed more abundantly in colon than in jejunum, ileum and stomach as indicated by Northern blots. Expression of mRNA from the colon of adults and children but not from other gastrointestinal regions in Xenopus oocytes enhanced the osmotic water permeability, and the urea and glycerol transport in a manner sensitive to an antisense AQP3 oligonucleotide, indicating the presence of functional AQP3. Immunocytochemistry and immunofluorescence studies in human colon revealed that the AQP3 protein is restricted to the villus epithelial cells. The immunostaining within these cells was more intense in the apical than in the basolateral membranes. The presence of AQP3 in villus epithelial cells suggests that AQP3 is implicated in water absorption across human colonic surface cells.

Angiotensin-(1-7) potentiates the coronary vasodilatatory effect of bradykinin in the isolated rat heart

It has been shown that angiotensin-(1-7) (Ang-(1-7)) infusion potentiates the bradykinin (BK)-induced hypotensive response in conscious rats. The present study was conducted to identify Ang-(1-7)-BK interactions in the isolated rat heart perfused according to the Langendorff technique. Hearts were excised and perfused through the aortic stump under a constant flow with Krebs-Ringer solution and the changes in perfusion pressure and heart contractile force were recorded. Bolus injections of BK (2.5, 5, 10 and 20 ng) produced a dose-dependent hypotensive effect. Ang-(1-7) added to the perfusion solution (2 ng/ml) did not change the perfusion pressure or the contractile force but doubled the hypotensive effect of the lower doses of BK. The BK-potentiating Ang-(1-7) activity was blocked by pretreatment with indomethacin (5 mg/kg, ip) or L-NAME (30 mg/kg, ip). The Ang-(1-7) antagonist A-779 (50 ng/ml in Krebs-Ringer) completely blocked the effect of Ang-(1-7) on BK-induced vasodilation. These data suggest that the potentiation of the BK-induced vasodilation by Ang-(1-7) can be attributed to the release of nitric oxide and vasodilator prostaglandins through an Ang-(1-7) receptor-mediated mechanism.

The role of complement in the modulation by fluid-phase IgG of the production of reactive oxygen species by polymorphonuclear leukocytes stimulated with IgG immune complexes

The production of reactive oxygen species (ROS) by polymorphonuclear leukocytes (PMN) can be induced by immune complexes and is an important component of phagocytosis in the killing of microorganisms, but can also be involved in inflammatory reactions when immune complexes are deposited in tissues. We have observed that fluid-phase IgG can inhibit the generation of ROS by rabbit PMN stimulated with precipitated immune complexes of IgG (ICIgG) in a dose-dependent manner, acting as a modulatory factor in the range of physiological IgG concentrations. This inhibitory effect is compatible with the known affinity (Kd) of monomeric IgG for the receptors involved (FcRII and FcRIII). The presence of complement components in the immune complexes results in a higher stimulation of ROS production. In this case, however, there is no inhibition by fluid-phase IgG. The effect of complement is strongly dependent on the presence of divalent cations (Ca2+ or Mg2+) in the medium, whereas the stimulation of ICIgG (without complement) does not depend on these cations. We have obtained some evidence indicating that iC3b should be the component involved in the effect of complement through interaction with the CR3 receptor. The absence of the inhibitory effect of fluid-phase IgG in ROS production when complement is present in the immune complex shows that complement may be important in vivo not only in the production of chemotactic factors for PMN, but also in the next phase of the process, i.e., the generation of ROS.

Central actions of glucocorticoids in the control of body fluid homeostasis: Review

The involvement of the hypothalamic-pituitary-adrenal axis in the control of body fluid homeostasis has been extensively investigated in the past few years. In the present study, we reviewed the recent results obtained using different approaches to investigate the effects of glucocorticoids on the mechanisms of oxytocin and vasopressin synthesis and secretion in response to acute and chronic plasma volume and osmolality changes. The data presented here suggest that glucocorticoids are not only involved in the mechanisms underlying the fast release but also in the transcriptional events that lead to decreased synthesis and secretion of these neuropeptides, particularly oxytocin, under diverse experimental conditions of altered fluid volume and tonicity. The endocannabinoid system, through its effects on glutamatergic neurotransmission within the hypothalamus and the nuclear factor κB-mediated transcriptional activity, seems to be also involved in the specific mechanisms by which glucocorticoids exert their central effects on neurohypophyseal hormone synthesis and secretion.

Addressing conflicts of interest in the research paper: a societal demand in contemporary science?

In the last decade, dialogue between science and society has found a forum in an increasing number of publications on topics such as public engagement with science and public trust in science. Concerning the latter, issues that include cases of research misconduct, accountability in research, and conflicts of interest (COIs) have shaped global discussions on the communication of science. In the publication setting, the perception that hiding COIs and/or not managing them well may affect public trust in the research record has grown among editors. We conducted a search for editorials addressing COIs between 1989 and 2011, using four major databases: Medline/PubMed, Embase, Scopus, and Web of Knowledge. We explored the content of these editorials and the relationship they established between COIs and the public trust in science. Our results demonstrate that the relationship between disclosure of COIs and public trust in science has become a major concern among editors. We, thus, argue that COIs should be discussed more openly and frequently in graduate courses in the sciences, around the globe, not only in biomedical but also in non-biomedical areas. This is a critical issue in contemporary science, as graduate students are the future voices and decision-makers of the research community. Therefore, COIs, especially in the broader context of science and society, merit closer attention from policymakers, researchers, and educators. At times of great expectations for public engagement with science, mishandling of COIs may have undesirable consequences for public engagement with science and confidence in the scientific endeavor.

Assessing development and the idea of development in the 1950s in Brazil

The decade of 1950s was a crucial period of the industrialization of the Brazilian economy. The dominant school of thought was the national-developmentalism, which was not restricted to the sphere of economic production but also encompassed political and socio-cultural processes of change. Combining repression, persuasion and paternalism, the national state took a significantly political and economic responsibility in the social, material and symbolic modernization during the Vargas and Kubitschek administrations. However, internal disputes, foreign demands and a long legacy of socio-spatial inequalities prevented the achievement of more socially inclusive goals, leading a legacy of unanswered questions that still have currency today.

The conclusion of the deduction of taste in the dialectic of the power of judgment aesthetic in Kant

In this paper, it is argued that only in the section on dialectic in the Critique of Judgment does Kant reach a definitive and conclusive version of deduction, after discovering the concept of the supersensible. In the section on the deduction of pure aesthetic judgments, Kant does not satisfactorily explain the critical distinction between the sensible nature of humanity and the supersensible nature of human reason presupposed in the concept of universal communicability. While the concept of the supersensible illustrates this distinction, it is only through this concept that Kant that can justify the specific possibility of claiming subjective validity in taste. The priority of the solution found in the dialectic is illustrated not only by a comparative analysis of the two sections, but also by a historical reconstruction of the process of the formation of the work, which shows that the first formulation of the concept of validity coincides with the use of the concept of the supersensible.