Control of the phosphorylation of the astrocyte marker glial fibrillary acidic protein (GFAP) in the immature rat hippocampus by glutamate and calcium ions: possible key factor in astrocytic plasticity

The present review describes recent research on the regulation by glutamate and Ca2+ of the phosphorylation state of the intermediate filament protein of the astrocytic cytoskeleton, glial fibrillary acidic protein (GFAP), in immature hippocampal slices. The results of this research are discussed against a background of modern knowledge of the functional importance of astrocytes in the brain and of the structure and dynamic properties of intermediate filament proteins. Astrocytes are now recognized as partners with neurons in many aspects of brain function with important roles in neural plasticity. Site-specific phosphorylation of intermediate filament proteins, including GFAP, has been shown to regulate the dynamic equilibrium between the polymerized and depolymerized state of the filaments and to play a fundamental role in mitosis. Glutamate was found to increase the phosphorylation state of GFAP in hippocampal slices from rats in the post-natal age range of 12-16 days in a reaction that was dependent on external Ca2+. The lack of external Ca2+ in the absence of glutamate also increased GFAP phosphorylation to the same extent. These effects of glutamate and Ca2+ were absent in adult hippocampal slices, where the phosphorylation of GFAP was completely Ca2+-dependent. Studies using specific agonists of glutamate receptors showed that the glutamate response was mediated by a G protein-linked group II metabotropic glutamate receptor (mGluR). Since group II mGluRs do not act by liberating Ca2+ from internal stores, it is proposed that activation of the receptor by glutamate inhibits Ca2+ entry into the astrocytes and consequently down-regulates a Ca2+-dependent dephosphorylation cascade regulating the phosphorylation state of GFAP. The functional significance of these results may be related to the narrow developmental window when the glutamate response is present. In the rat brain this window corresponds to the period of massive synaptogenesis during which astrocytes are known to proliferate. Possibly, glutamate liberated from developing synapses during this period may signal an increase in the phosphorylation

Options listing and the volatility of the underling asset: a study on the derivative market function

There are basic misunderstandings on derivative markets. Some professionals believe that they are a kind of casinos and have no utility for the investors. This work looks at the effects of options introduction in the Brazilian market, seeking for another benefit for this introduction: changes in the stocks risk leveI. Our results are the same found in the US and other markets: the options introduction reduces the stocks volatility. We also found that there is a slight indication that the volatility becames more stochastic with this alternative.

Key factors in working capital management in the Brazilian market

Many studies have been conducted in corporate finance regarding long-term investment and financing decisions. However, short-term asset investments play a significant role in the balance sheet of companies. Moreover, financial managers dedicate significant amounts of time and effort to the subject of working capital management, balancing current assets and liabilities. This paper provides insights regarding the key factors of working capital management by exploring the internal variables of a number of companies. This study used data from 2,976 Brazilian public companies from 2001 to 2008, and found that debt level, size and growth rate can affect the working capital management of companies.

Competitiveness of tourist destinations: the study of 65 key destinations for the development of regional tourism

Tourism has reached world importance in the economy. The competition in tourism has intensified between destinations, whether the destinations are cities, regions or countries. In this sense, the evaluation of the tourism competitiveness of these destinations may be helpful in planning and prioritizing actions that will benefit the industry. This article discusses the concept of competitiveness by the multidimensional view of performance, efficiency and unit analysis. Using the theoretical framework lifted, this article shows the 'Study on the competitiveness of the 65 destinations inducers of regional tourism development' prepared by the Tourism Ministry, the Brazilian Support Service to Micro and Small Enterprises (Sebrae) and Getulio Vargas Foundation (FGV), its assumptions that guided this study as well its methodological aspects. Based on this methodology, it was carried out a diagnosis of these 65 destinations selected by the Brazilian Ministry of Tourism to be inducers of tourism in their respective regions. The result of competitiveness reached by these 65 inductors destinations is presented in this article, providing a map of the level of competitiveness of tourism in Brazil.

Effects of the length and timing of nighttime naps on task performance and physiological function

OBJECTIVE: To examine the effects of the length and timing of nighttime naps on performance and physiological functions, an experimental study was carried out under simulated night shift schedules. METHODS: Six students were recruited for this study that was composed of 5 experiments. Each experiment involved 3 consecutive days with one night shift (22:00-8:00) followed by daytime sleep and night sleep. The experiments had 5 conditions in which the length and timing of naps were manipulated: 0:00-1:00 (E60), 0:00-2:00 (E120), 4:00-5:00 (L60), 4:00-6:00 (L120), and no nap (No-nap). During the night shifts, participants underwent performance tests. A questionnaire on subjective fatigue and a critical flicker fusion frequency test were administered after the performance tests. Heart rate variability and rectal temperature were recorded continuously during the experiments. Polysomnography was also recorded during the nap. RESULTS: Sleep latency was shorter and sleep efficiency was higher in the nap in L60 and L120 than that in E60 and E120. Slow wave sleep in the naps in E120 and L120 was longer than that in E60 and L60. The mean reaction time in L60 became longer after the nap, and faster in E60 and E120. Earlier naps serve to counteract the decrement in performance and physiological functions during night shifts. Performance was somewhat improved by taking a 2-hour nap later in the shift, but deteriorated after a one-hour nap. CONCLUSIONS: Naps in the latter half of the night shift were superior to earlier naps in terms of sleep quality. However performance declined after a 1-hour nap taken later in the night shift due to sleep inertia. This study suggests that appropriate timing of a short nap must be carefully considered, such as a 60-min nap during the night shift.

HIV rapid testing as a key strategy for prevention of mother-to-child transmission in Brazil

OBJECTIVE: To assess the feasibility of HIV rapid testing for pregnant women at maternity hospital admission and of subsequent interventions to reduce perinatal HIV transmission. METHODS: Study based on a convenience sample of women unaware of their HIV serostatus when they were admitted to delivery in public maternity hospitals in Rio de Janeiro and Porto Alegre, Brazil, between March 2000 and April 2002. Women were counseled and tested using the Determine HIV1/2 Rapid Test. HIV infection was confirmed using the Brazilian algorithm for HIV infection diagnosis. In utero transmission of HIV was determined using HIV-DNA-PCR. There were performed descriptive analyses of sociodemographic data, number of previous pregnancies and abortions, number of prenatal care visits, timing of HIV testing, HIV rapid test result, neonatal and mother-to-child transmission interventions, by city studied. RESULTS: HIV prevalence in women was 6.5% (N=1,439) in Porto Alegre and 1.3% (N=3.778) in Rio de Janeiro. In Porto Alegre most of women were tested during labor (88.7%), while in Rio de Janeiro most were tested in the postpartum (67.5%). One hundred and forty-four infants were born to 143 HIV-infected women. All newborns but one in each city received at least prophylaxis with oral zidovudine. It was possible to completely avoid newborn exposure to breast milk in 96.8% and 51.1% of the cases in Porto Alegre and Rio de Janeiro, respectively. Injectable intravenous zidovudine was administered during labor to 68.8% and 27.7% newborns in Porto Alegre and Rio de Janeiro, respectively. Among those from whom blood samples were collected within 48 hours of birth, in utero transmission of HIV was confirmed in 4 cases in Rio de Janeiro (4/47) and 6 cases in Porto Alegre (6/79). CONCLUSIONS: The strategy proved feasible in maternity hospitals in Rio de Janeiro and Porto Alegre. Efforts must be taken to maximize HIV testing during labor. There is a need of strong social support to provide this population access to health care services after hospital discharge.

Immunopathology of human schistosomiasis mansoni: I. Immunomodulatory influences on T cell function

Cell mediated immune response was studied in patients with recent and chronic Schistosoma mansoni infection. Precultured peripheral mononuclear cells showed significantly higher responses to S. mansoni adult worm antigen (SAWA) when compared to fresh cell preparations. The addition of each patient serum to the precultured cells reactions to SAWA or recall antigens demonstrated a strong inhibitory serum action, which was also noted on allogeneic cells derived from healthy subjects. The CD4 subset was the main responding cell to SAWA being this reactivity highly suppressed by the presence of the monocyte macrophage accessory cells. We stressed the simultaneous inhibitory action of humoral and cellular factors on the specific cell response to S. mansoni.

Labeling of Salmonella Typhymurium with iodine-131 to study phagocytic function in rats

The present study describes a method for labeling Salmonella typhymurium with iodine-131 to evaluate both the morphological and the functional characteristics of the reticulo-endothelial system. A suspension containing 2 x 10(9) bacteria per ml was labeled with carrier-free Na131I without reductor, with a labeling yield of 46.5 ± 3% and 3.5 ± 1.3% of free Iodine-131. The biodistribution of the labeled bacteria in rats was studied with a large field-of-view scintillation camera equiped with a pinhole collimator. Whole body images were obtained 15 and 30 minutes after intravenous injection of the labeled microorganisms. Images showed accumulation of bacteria in the liver and both normal and transplanted spleens of the animals. Autoradiographs of liver and spleen demonstrated labeled bacteria within the cells of the reticulo-endothelial system. The method described is easy to perform, has a good labeling yield and allows the functional evaluation of the reticulo-monophagocytic system, including transplanted spleens.

Lymphocyte subpopulations and neutrophil function in chronic human Chagas' disease

The absolute numbers of total leukocytes, lymphocytes, T cells, helper/inducer, suppressor/cytotoxic and B cells were decreased in the peripheral blood of patients with chronic Chagas' disease. Since antilymphocyte antibodies were present only in a minority of patients they probably cannot account for the abnormalities in lymphocyte subsets. Patient neutrophils stimulated with endotoxin-treated autologous plasma showed depressed chemotactic activity and this seems to be an intrinsic cellular defect rather than plasma inhibition. Random migration of neutrophils was normal. Reduction of nitroblue tetrazolium by endotoxin- stimulated neutrophils was also decreased. These findings further document the presence of immunosuppression in human Chagas' disease. They may be relevant to autoimmunity, defense against microorganisms and against tumor cells at least in a subset of patients with more severe abnormalities.

Adrenal function in 23 children with paracoccidioidomycosis

Adrenal involvement by Paracoccidioides brasiliensis was described at necropsies and in many clinical studies, but only in adults. Therefore, the aim of this study was to evaluate adrenal function in children with paracoccidioidomycosis. Twenty-three children with the systemic form of paracoccidioidomycosis were evaluated and divided in two Groups: Group A (n = 8) included children before treatment and Group B (n = 15) children after the end of treatment. Plasma cortisol (basal and after ACTH test), ACTH, renin activity, aldosterone, sodium and potassium were measured. They were within normal range in all cases, except for renin activity and aldosterone, which were elevated in some cases. Group A patients showed basal and post-ACTH cortisol levels significantly greater than Group B patients. The results showed that adrenal function was not compromised in these children with paracoccidioidomycosis.

TWO NEW RECORDS OF Isomyia paurogonita FANG AND FAN, 1986 AND Sumatria latifrons Malloch, 1926 (DIPTERA: CALLIPHORIDAE) FROM NORTHERN THAILAND, WITH REVISED KEY TO THE SPECIES OF Isomyia

During the annual fly survey at Doi Nang Kaew in Doi Saket District, Chiang Mai Province of Thailand in 2011, Isomyia paurogonitaFang & Fan, 1986 (Diptera: Calliphoridae) and Sumatria latifrons Malloch, 1926 (Diptera: Calliphoridae) were collected for the first time in Thailand. They are the rare species of the subfamily Rhiniinae (tribe Cosminini). Prior to this finding, fifteen species of Isomyia and two species of Sumatriawere recorded from Thailand. Therefore, 96 blow fly species have been found in this country. These new locality records of both flies are very important for further research on their biology and ecology in Thailand.

Liver function evaluation in leptospirosis with colloidal gold 1 9 8 Au

Eight patients with leptospirosis were studied with colloidal gold 1 9 8 Au. The radiocolloidal hepatic distribution was altered, presenting a non-homogeneous tiver concentration in seven cases, and a minute to moderate splenic visualization in five. Two patients presented doubtful splenic image, and one seemed to be normal. Liver scanning with colloidal gold 1 9 8 Au is demonstra ted to be a good liver function test.