Intestinal apoptotic changes linked to metabolic status in fasted and refed rats

Intestinal apoptosis and expression of apoptosis inducers - the cytokines TNFalpha, TGFbeta1 - and the intestinal transcription factor Cdx2, were studied according to two different metabolic and hormonal phases which characterize long-term fasting: the long period of protein sparing during which energy expenditure is derived from lipid oxidation (phase II), and the later phase characterized by a rise in body protein utilization and plasma corticosterone (phase III). Apoptosis was further studied in 2, 6, and 24 h refed rats. Morphological apoptotic events were observed by environmental and conventional scanning electron microscopy and a TUNEL test was used to characterize the final stages of apoptotic death. The gene and protein expressions of TNFalpha, TGFbeta1, and Cdx2 were measured. Apoptotic events and TNFalpha, TGFbeta1, and Cdx2 gene and protein expressions did not vary significantly during phase II as compared to the normally fed animals. However, a phase III fasting induced a delay in intestinal epithelial apoptosis, along with a 92, 58, and 25% decrease in TNFalpha, TGFbeta1, and Cdx2 mRNAs, respectively. The amounts of TNFalpha, TGFbeta1, and Cdx2 proteins decreased by 70, 36, and 25%, respectively. Apoptosis was restored rapidly after a 2 h refeeding following the phase III, accompanied by a significant increase in TNFalpha, TGFbeta1, and Cdx2 mRNA and the protein levels, compared to the phase III fasting values. The concomitant decreases in cytokines and Cdx2 and in apoptotic cells during phase III suggest the preservation of enterocytes during this critical fasting period in order to optimize nutrient absorption as soon as food is available and thus, to rapidly restore body mass

Formação continuada dos professores dos anos iniciais do ensino fundamental e sua implicação para o trabalho docente

O presente artigo apresenta dados parciais de uma pesquisa referente as ações de formação continuada para os docentes que trabalham nos anos iniciais da Rede Municipal de Ensino de uma cidade da região sul do Brasil. O objetivo central é conhecer as percepções dos professores dos anos iniciais do ensino fundamental sobre as características mais importantes que um curso de formação continuada deveria contemplar. Fundamentaram teoricamente os dados Imbernón (2009), Gatti (2009), Romanowski (2010) e Formosinho (2009). Entende-se a formação continuada como um processo contínuo de mudança e ressignificação, e não mais como um acúmulo de conhecimento por meio de palestras e cursos. A pesquisa desenvolvida é do tipo survey e o questionário foi o instrumento de coleta de dados. Responderam ao instrumento de pesquisa, 140 professores dos anos iniciais do Ensino Fundamental, concursados, formados em pedagogia e com 40 horas de contrato de trabalho. Os resultados apontaram que as características que mais se sobressaem são o enfoque nas práticas pedagógicas e o envolvimento e participação do professor nessa formação. Assim, percebe-se o anseio dos docentes para serem ouvidos, e que seus conhecimentos e experiências vividas no cotidiano escolar sejam levadas em consideração na hora de planejar as ações de formação continuada. Os dados mostram que a Secretaria de Educação poderia se beneficiar com as ideias, opiniões e sugestões dos professores, caso os ouvisse sobre suas necessidades formativas

The Torpid State:Recent Advances in Metabolic Adaptations and Protective Mechanisms(dagger)

Torpor and hibernation are powerful strategies enabling animals to survive periods of low resource availability. The state of torpor results from an active and drastic reduction of an individual's metabolic rate (MR) associated with a relatively pronounced decrease in body temperature. To date, several forms of torpor have been described in all three mammalian subclasses, i.e., monotremes, marsupials, and placentals, as well as in a few avian orders. This review highlights some of the characteristics, from the whole organism down to cellular and molecular aspects, associated with the torpor phenotype. The first part of this review focuses on the specific metabolic adaptations of torpor, as it is used by many species from temperate zones. This notably includes the endocrine changes involved in fat- and food-storing hibernating species, explaining biomedical implications of MR depression. We further compare adaptive mechanisms occurring in opportunistic vs. seasonal heterotherms, such as tropical and sub-tropical species. Such comparisons bring new insights into the metabolic origins of hibernation among tropical species, including resistance mechanisms to oxidative stress. The second section of this review emphasizes the mechanisms enabling heterotherms to protect their key organs against potential threats, such as reactive oxygen species, associated with the torpid state. We notably address the mechanisms of cellular rehabilitation and protection during torpor and hibernation, with an emphasis on the brain, a central organ requiring protection during torpor and recovery. Also, a special focus is given to the role of an ubiquitous and readily-diffusing molecule, hydrogen sulfide (H2S), in protecting against ischemia-reperfusion damage in various organs over the torpor-arousal cycle and during the torpid state. We conclude that (i) the flexibility of torpor use as an adaptive strategy enables different heterothermic species to substantially suppress their energy needs during periods of severely reduced food availability, (ii) the torpor phenotype implies marked metabolic adaptations from the whole organism down to cellular and molecular levels, and (iii) the torpid state is associated with highly efficient rehabilitation and protective mechanisms ensuring the continuity of proper bodily functions. Comparison of mechanisms in monotremes and marsupials is warranted for understanding the origin and evolution of mammalian torpor

Geophagy Practices and the Content of Chemical Elements in the Soil Eaten by Pregnant Women in Artisanal and Small Scale Gold Mining Communities in Tanzania.

Geophagy, a form of pica, is the deliberate consumption of soil and is relatively common across Sub-Saharan Africa. In Tanzania, pregnant women commonly eat soil sticks sold in the market (pemba), soil from walls of houses, termite mounds, and ground soil (kichuguu). The present study examined geophagy practices of pregnant women in a gold mining area of Geita District in northwestern Tanzania, and also examined the potential for exposure to chemical elements by testing soil samples. We conducted a cross sectional study using a convenience sample of 340 pregnant women, ranging in age from 15-49 years, who attended six government antenatal clinics in the Geita District, Tanzania. Structured interviews were conducted in June-August, 2012, to understand geophagy practices. In addition, soil samples taken from sources identified by pregnant women practicing geophagy were analysed for mineral element content. Geophagy was reported by 155 (45.6%) pregnant women with 85 (54.8%) initiating the practice in the first trimester. A total of 101 (65%) pregnant women reported eating soil 2 to 3 times per day while 20 (13%) ate soil more than 3 times per day. Of 155 pregnant women 107 (69%) bought pemba from local shops, while 48 (31%) consumed ground soil kichuguu. The estimated mean quantity of soil consumed from pemba was 62.5 grams/day. Arsenic, chromium, copper, iron, manganese, nickel and zinc levels were found in both pemba and kichuguu samples. Cadmium and mercury were found only in the kichuguu samples. Based on daily intake estimates, arsenic, copper and manganese for kichuguu and copper and manganese for pemba samples exceed the oral Minimum Risk Levels designated by the U.S. Agency for Toxic Substance and Disease Registry. Almost 50% of participants practiced geophagy in Geita District consistent with other reports from Africa. Both pemba and kichuguu contained chemical elements at varying concentration, mostly above MRLs. As such, pregnant women who eat soil in Geita District are exposed to potentially high levels of chemical elements, depending upon frequency of consumption, daily amount consumed and the source location of soil eaten

Seasonal variations in the diet and food selection of the Algerian hedgehog Atelerix algirus

The Algerian hedgehog Atelerix algirus is an insectivorous species. However, the exact composition of its natural diet remains largely undetermined, especially in relation to seasonal variations in food availability. From March to November, we simultaneously analysed the composition of 180 hedgehog faecal samples and food availability in the Soumman Valley, Algeria to assess food selection in this species. The faeces contained 196 different prey species, of which 92% belonged to the class Insecta. The highest prey species diversity was found in the Coleoptera order (100 species recorded) and the highest species occurrence was found in Hymenoptera (65% of the prey items, mainly represented by the harvester ant Messor barbarus, a crop-ravaging species). This study shows that the Algerian hedgehog is mainly a generalist species with a diet that is strongly linked to food availability. However, seasonal variations were observed in prey selection, and a notable shift in food preference was observed during autumn. The exact nature of these changes in feeding behaviour remains to be investigated, notably in relation to changes in energy requirements of this species before hibernation, in terms of quantity and/or quality

Étude du fonctionnement testiculaire chez le hérisson d’algérie (Atelerix algirus)

Cette étude nous montre que le Hérisson d’Algérie présente un cycle sexuel caractérisé par un repos automnal, une reprise hivernale et une activité printanière.The analysis of the histological sections of the testis and the epididymis of the Hedgehog showed that during the month of October, spermatogenesis is stopped at the primary spermatocyte stage and the seminiferous tubes are small (19.66±3.56 µm). During the months of May and June, spermatogenesis was activated. The seminiferous tubules increased in size (28.27±3.28 µm) and showed signs of spermatogenetic activity. This study shows that the Algerian Hedgehog has a sexual cycle characterized by an autumnal rest, a winter recovery and spring activit

Acute toxicity of two pesticides (dursban, mancozeb) and their combined mixture on the terrestrial isopod Armadillidium vulgare (Oniscidea, Isopoda)

Our study focused on evaluating an acute toxicity test, where woodlice (Armadillidium vulgare) which is the most abandoned in our region , were exposed to pesticides (dursban and mancozeb) most used in Algeria.The concentrations of the pesticids tested are 720 mg/kg,360 mg/kg,90 mg/kg, 45 mg/kg for dursban; 800 mg/kg, 400 mg/kg, 200 mg/kg,100 mg/kg for mancozeb and 720/800 mg/kg, 360/400 mg/kg,90/200 mg/kg, 45/100 mg/kg for the mixture of dursban and mancozeb.Our results show that dursban was highly toxic (69% mortality after 28 days of the test) compared to mancozeb (19.5% mortality). On the other hand, in the case of the mixture (dursban ± mancozeb), the toxicity was lower (63% mortality) compared to the dursban tested alone. Contamination of woodlice with dursban and a mixture of dursban and mancozeb revealed morphological effects such as alteration of the marsupial cavity and expulsion of eggs from the outside of this cavity. Dursban and the mixture of dursban and mancozeb are toxic to Armadillidium vulgare, but mancozeb alone is not toxic. Dursban should be banned because it is bad for soil fauna and therefore probably for biodiversity in general and even human health

Intestinal gluconeogenesis and glucose transport according to body fuel availability in rats

Intestinal hexose absorption and gluconeogenesis have been studied in relation to refeeding after two different fasting phases: a long period of protein sparing during which energy expenditure is derived from lipid oxidation (phase II), and a later phase characterized by a rise in plasma corticosterone triggering protein catabolism (phase III). Such a switch in body fuel uses, leading to changes in body reserves and gluconeogenic precursors, could modulate intestinal gluconeogenesis and glucose transport. The gene and protein levels, and the cellular localization of the sodium-glucose cotransporter SGLT1, and of GLUT5 and GLUT2, as well as that of the key gluconeogenic enzymes phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (Glc6Pase) were measured. PEPCK and Glc6Pase activities were also determined. In phase III fasted rats, SGLT1 was up-regulated and intestinal glucose uptake rates were higher than in phase II fasted and fed rats. PEPCK and Glc6Pase mRNA, protein levels and activities also increased in phase III. GLUT5 and GLUT2 were down-regulated throughout the fast, but increased after refeeding, with GLUT2 recruited to the apical membrane. The increase in SGLT1 expression during phase III may allow glucose absorption at low concentrations as soon as food is available. Furthermore, an increased epithelial permeability due to fasting may induce a paracellular movement of glucose. In the absence of intestinal GLUT2 during fasting, Glc6Pase could be involved in glucose release to the bloodstream via membrane trafficking. Finally, refeeding triggered GLUT2 and GLUT5 synthesis and apical recruitment of GLUT2, to absorb larger amounts of hexoses