Temperature influence and social interaction on the frequency of electric organ discharges in Rhamphicthys rostratus.

The frequency of electric organ discharges (EOD) of a gymnotiform fish of "pulse" frequency (40-100 Hz) from South America - Ramphicthys rostratuswas studied. The animals were settled in pairs in a aquarium and thus observed: variation in EOD frequency had at least two components: one more positively correlated with temperature, another less positively correlated due to social interaction.

Trypanosoma cruzi: effect of phenothiazines on the parasite and its interaction with host cells

Phenothiazines were observed to have a direct effect on Trypanosoma cruzi and on its in vitro interaction with host cells. They caused lysis of trypomastigotes (50 uM/24 h) and,to a lesser extent, epimastigote proliferation. Treatment of infected peritoneal macrophages with 12.5 uM chlorpromazine or triflupromazine inhibited the infection; this effect was found to be partially reversible if the drugs were removed after 24 h of treatment. At 60 uM, the drugs caused damage to amastigotes interiorized in heart muscle cells. However, the narrow margin of toxity between anti-trypanossomal activity and damage to host cells mitigates against in vivo investigation at the present time. Possible hypothesis for the mechanism of action of phenothiazines are discussed.

Effects of azadirachtin on Rhodnius prolixus: immunity and trypanosoma interaction

The effects of azadirachtin, a tetranortriterpenoid from the neem tree Aradirachta indica J. on both immunity and Trypanosoma cruzi interaction within Rhodniusprolixus and other triatomines, were presented Given through a blood meal, azadirachtin affected the immune reactivity as shown by a significant reduction in numbers of hemocytes and consequently nodule formation follwing challenge with Enterobacter cloacae ß12, reduction in ability to produce antibacterial activities in the hemolymph when injected with bacteria, and decreased ability to destroy the infection caused by inoculation of E. cloacae cells. A single dose of azadirachtin was able to block the development of T. cruzi in R. prolixus if given through the meal at different intervals, together with, before or after parasite infection. Similary, these results were observed with different triatomine species and different strains of T. cruzi. Azadirachtin induced a permanent resistance of the vector against reinfection with T. cruzi. The significance of these data is discussed in relation to the general mode of azadirachtin action in insects.

Clinical treatment adherence of health care workers and students exposed to potentially infectious biological material

OBJECTIVE To assess adherence to clinical appointments by health care workers (HCW) and students who suffered accidents with potentially infectious biological material. METHOD A retrospective cross-sectional study that assessed clinical records of accidents involving biological material between 2005 and 2010 in a specialized unit. RESULTS A total of 461 individuals exposed to biological material were treated, of which 389 (84.4%) were HCWs and 72 (15.6%) students. Of the 461 exposed individuals, 307 (66.6%) attended a follow-up appointment. Individuals who had suffered an accident with a known source patient were 29 times more likely to show up to their scheduled follow-up appointments (OR: 29.98; CI95%: 16.09-55.83). CONCLUSION The predictor in both univariate and multivariate analyses for adherence to clinical follow-up appointment was having a known source patient with nonreactive serology for the human immunodeficiency virus and/or hepatitis B and C.

Genotype and environment interaction on soybean yield in Mato Grosso State, Brazil

The objective of this work was to investigate the genotype-environment interaction in Mato Grosso State, MT. The relative importance of locations, years, sowing dates and cultivars and their interactions was analyzed from data collected in regional yield trials performed in a randomized complete block design with four replications, from 1994-1995 through 1999-2000, in nine locations and two sowing dates. Individual and pooled analyses of variance over years and locations were performed. Complementary analyses of variances partitioned MT State in two main and five smaller regions, respectively: North and South of Cuiabá; and MT-South-A (Pedra Preta area), MT-South-B (Rondonópolis and Itiquira), MT-East (Primavera do Leste and Campo Verde), MT-Central (Nova Mutum, Lucas do Rio Verde and Sorriso) and MT-Parecis (Campo Novo dos Parecis and Sapezal). Locations are relatively more important than years for yield testing soybeans in the MT State, therefore, investment should be made in increasing locations rather than years to improve experimental precision. Partitioning the MT State into regions has little impact on soybean yield testing results and, consequently, on the efficiency of the soybean breeding program in the State. Breeding genotypes with broad adaptation for the MT State is an efficient strategy for cultivar development.

Rotavirus and reovirus interaction with mouse peritoneal resident phagocytic cells

Rotaviruses and reoviruses are involved in human and animal diseases. It is known that both viruses penetrate the gastrointestinal tract but their interaction with phagocytic cells is unknown. To study this interaction, peritoneal resident phagocytic cells were used and rotavirus and reovirus replication in peritoneal phagocytic cells was observed. However, rotavirus replication in these cells led to the production of defective particles since MA-104 cells inoculated with rotavirus phagocytic cell lysate did not show any evidence of virus replication. On the basis of these results, we suggest that, although reovirus dissemination may be helped by these phagocytic cells, these cells may control rotavirus infection and probably contribute to the prevention of its dissemination.

Activity and functional interaction of alternative oxidase and uncoupling protein in mitochondria from tomato fruit

Cyanide-resistant alternative oxidase (AOX) is not limited to plant mitochondria and is widespread among several types of protists. The uncoupling protein (UCP) is much more widespread than previously believed, not only in tissues of higher animals but also in plants and in an amoeboid protozoan. The redox energy-dissipating pathway (AOX) and the proton electrochemical gradient energy-dissipating pathway (UCP) lead to the same final effect, i.e., a decrease in ATP synthesis and an increase in heat production. Studies with green tomato fruit mitochondria show that both proteins are present simultaneously in the membrane. This raises the question of a specific physiological role for each energy-dissipating system and of a possible functional connection between them (shared regulation). Linoleic acid, an abundant free fatty acid in plants which activates UCP, strongly inhibits cyanide-resistant respiration mediated by AOX. Moreover, studies of the evolution of AOX and UCP protein expression and of their activities during post-harvest ripening of tomato fruit show that AOX and plant UCP work sequentially: AOX activity decreases in early post-growing stages and UCP activity is decreased in late ripening stages. Electron partitioning between the alternative oxidase and the cytochrome pathway as well as H+ gradient partitioning between ATP synthase and UCP can be evaluated by the ADP/O method. This method facilitates description of the kinetics of energy-dissipating pathways and of ATP synthase when state 3 respiration is decreased by limitation of oxidizable substrate.

Development of new heparin-like compounds and other antithrombotic drugs and their interaction with vascular endothelial cells

The anticlotting and antithrombotic activities of heparin, heparan sulfate, low molecular weight heparins, heparin and heparin-like compounds from various sources used in clinical practice or under development are briefly reviewed. Heparin isolated from shrimp mimics the pharmacological activities of low molecular weight heparins. A heparan sulfate from Artemia franciscana and a dermatan sulfate from tuna fish show a potent heparin cofactor II activity. A heparan sulfate derived from bovine pancreas has a potent antithrombotic activity in an arterial and venous thrombosis model with a negligible activity upon the serine proteases of the coagulation cascade. It is suggested that the antithrombotic activity of heparin and other antithrombotic agents is due at least in part to their action on endothelial cells stimulating the synthesis of an antithrombotic heparan sulfate.

The Need for Pedagogical Qualifications for Teaching Cardiology to Undergraduate Students

OBJECTIVE: To report a training program in cardiology emphasizing changes in its pedagogical practice. These changes were put into practice by some teachers at the Medical School of Porto Alegre of the University of Rio Grande do Sul (FAMED/UFRGS) aiming to make faculty and student activities more dynamic and to promote more efficacious learning. The training program is directed at 5th semester medical students and aims at a behavioral change in teachers and students to promote more interaction, to favor exchanges, and to make the teaching-learning process easier, always maintaining the patient in the center of the medical activity. METHODS: The program emphasizes the definition of general and specific objectives for each activity to be developed by the students, with training in the area of admission to the cardiology service, with special emphasis on behavioral change in the cognitive, motor, affective, and attitudinal areas. Knowledge was developed by means of interactive seminars with initial and final assessment tests to identify students' and teachers' performance. The students were evaluated in an immediate, continuous, and progressive way in their daily activities and through comparison of the results of 2 tests, one applied at the beginning of the training and the other at its end. These 2 tests contained the same questions. RESULTS: We systematically assessed 560 students over 4 years. The mean grades of the tests performed prior to and after the 244 seminars were 7.38±1.66 and 9.17± 0.82, respectively (p<0.0001). For the tests applied at the beginning and at the end of the training, the mean grades were 5.61±1.61 and 9.37±0.90, respectively (p<0.0001). CONCLUSION: The program proved to be efficient both for the students' learning and for assessing their performance in a systematic and objective way.

Group mentoring for junior medical students: perceptions of mentees and mentors

Entering medical school can be associated with a number of difficulties that can hinder students' performance. Mentoring programs are designed to help students circumvent difficulties and improve their learning and personal development. The current study aimed to evaluate the perceptions of both students and mentors regarding a recently introduced, group-based mentoring program designed to support first-year students. After one year of regular meetings, students and mentors' perceptions of the program were assessed by means of structured questionnaires. Response content categories were identified through multiple readings. Both regular attendees and non-participating students had positive opinions about the program. Mentors were highly satisfied at having participated and acknowledged that the program has been useful not only for assisting students, but also for fostering their own personal and professional development. In conclusion, the group-based mentoring program is feasible and can elicit positive views from both mentors and students. In addition, faculty members' participation as mentors can also be beneficial, since the program appears to contribute to their own personal and professional development

Interaction between substance P and gastrin-releasing peptide on thyrotropin secretion by rat pituitary in vitro

The effect of substance P (SP) on thyrotropin (TSH) secretion is controversial. In this study we evaluated the effect of SP on TSH secretion by hemipituitaries of 3-month-old Wistar rats in vitro and its interaction with gastrin-releasing peptide (GRP) at equimolar concentrations (1 µM and 10 µM). TSH release was measured under basal conditions and 30 min after incubation in the absence or presence of SP, GRP or both peptides. Pituitary TSH content was also measured in the pituitary homogenate after incubation. SP at both concentrations caused a significant (P<0.05) increase in TSH secretion compared with all other groups, which was approximately 60% (1 µM) and 85% (10 µM) higher than that of the control group (23.3 ± 3.0 ng/ml). GRP at the lower concentration did not produce a statistically significant change in TSH secretion, whereas at the concentration of 10 µM it produced a 50% reduction in TSH. GRP co-incubated with substance P completely blocked the stimulatory effect of SP at both concentrations. Pituitary TSH content decreased in the SP-treated group compared to controls (0.75 ± 0.03 µg/hemipituitary) at the same proportion as the increase in TSH secretion, and this effect was also blocked when GRP and SP were co-incubated. In conclusion, in an in vitro system, SP increased TSH secretion acting directly at the pituitary level and this effect was blocked by GRP, suggesting that GRP is more potent than SP on TSH secretion, and that this inhibitory effect could be the predominant effect in vivo.

Effect of ATP and 2-oxoglutarate on the in vitro interaction between the NifA GAF domain and the GlnB protein of Azospirillum brasilense

Azospirillum brasilense is a diazotroph that associates with important agricultural crops and thus has potential to be a nitrogen biofertilizer. The A. brasilense transcription regulator NifA, which seems to be constitutively expressed, activates the transcription of nitrogen fixation genes. It has been suggested that the nitrogen status-signaling protein GlnB regulates NifA activity by direct interaction with the NifA N-terminal GAF domain, preventing the inhibitory effect of this domain under conditions of nitrogen fixation. In the present study, we show that an N-terminal truncated form of NifA no longer required GlnB for activity and lost regulation by ammonium. On the other hand, in trans co-expression of the N-terminal GAF domain inhibited the N-truncated protein in response to fixed nitrogen levels. We also used pull-down assays to show in vitro interaction between the purified N-terminal GAF domain of NifA and the GlnB protein. The results showed that A. brasilense GlnB interacts directly with the NifA N-terminal domain and this interaction is dependent on the presence of ATP and 2-oxoglutarate.

Decomposition of ground biomass of secondary forest and yield of annual crops in no tillage

ABSTRACT The objective of this work was to evaluate the dynamics of decomposition process of chopped secondary forest system, previously enriched with legumes Inga velutina Willd. and Stryphnodendron pulcherrimum (Willd.) Hochr. and the contribution of this process to the nutrient input to the cultivation of corn and bean under no-tillage. The experimental design was a randomized block, split plot with four replications. The plots were two species (I. velutina and S. pulcherrimum) and the subplots were seven times of evaluation (0, 7, 28, 63, 189, 252, 294 days after experiment installation). There was no difference (p ≥ 0.05) between the secondary forest systems enriched and no interaction with times for biomass waste, decomposition constant and half-life time. The waste of S. pulcherrimum trees had higher (p < 0.05) C/N ratio than that I. velutina. However, this one was higher (p < 0.05) in lignin content. Nevertheless, the dynamics of residue decomposition was similar. The corn yield was higher (p < 0.05) in cultivation under I.velutina waste. Meanwhile, the beans planted after corn, shows similar (p > 0.05) yield in both areas, regardless of the waste origin.

Higher education of tourism in Spain and its adaptation to the European higher education area

The international tourism system has deeply undergone structural changes in the last decades which not remain outside the subsystem higher education in tourism, especially in the European case. This article has two objectives: firstly, describes the European higher education area and the objectives, skills and subjects taught in the main Spanish universities that offer higher education in tourism. On the other hand, in the light of knowledge that researchers' descriptive models, provide experience of the implementation of European credit and thorough a deeply review of the literature on the topic higher education in tourism, to propose strategies that will enable other tourism higher education systems approach to the European reality. These policy proposals are aimed at agents and elements from higher education in tourism subsystem and they specifically include: the institutions providing education in tourism, the curriculum, the teaching methods, teachers and students.