956 resultados para Central and peripheral chemoreflex


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Achiridae is an important family of the order Pleuronectiformes widely distributed in North, Central, and South America with freshwater and marine species. In the present study cytogenetic analyses comprising conventional and molecular techniques were carried out in seven species of this family. The following diploid numbers (2n) and fundamental numbers (FN) were obtained: Achirus declivis 2n = 34, FN = 52; Achirus lineatus 2n = 40, FN = 66; Catathyridium jenynsi 2n = 40 and FN = 50; Gymnachirus nudus 2n = 36 and FN = 50; Hypoclinemus mentalis 2n = 38 and FN = 54; Trinectes paulistanus 2n = 42 and FN = 52; and Trinectes sp. 2n = 38 and FN = 54. All species presented a single nucleolar organizer region (NOR) bearing chromosome pair and C-band positive segments mainly distributed at the pericentromeric position. The wide variation observed in chromosome number and FN suggests the occurrence of larger chromosome rearrangements in the family Achiridae if compared with other families of the same order.

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Sorubim lima is a migratory catfish that do not reproduce in lenthic environments such as those formed after construction of hydroelectric power plants. An alternative for conservation of the species in these environments is the stocking with fingerlings produced in captivity. The technique used to reproduce it in captivity was the induction by carp pituitary hormone, with dosage of 5 mg.kg(-1) for females (1 mg.kg(-1) in the first dose and 4 mg.kg(-1) in the second) and 3 mg.kg(-1) for males (1 mg.kg(-1) in the first dose and 2 mg.kg(-1) in the second), with an interval of 14 hours. The determination of extrusion moment of oocytes was made by monitoring the migration of nucleus from central to peripheral position. After UTA 264.5 (accumulated thermal units) the oocytes were obtained by compression of the ventral region of the female, and male were sacrificed for extraction of sperm. The eggs were kept in an incubator and the time of hatching of larvae was 370 UTA. The larvae were initially fed with plankton and showed no cannibalism. Moreover, they were not demanding about the food, accepting prepared rations after fifteenth day of life. The weight gain of larvae was very low even close to 20 mm in length (14 days), not exceeding 0.05 mg per day. After that both weight and length increased rapidly.

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Breeds of sheep with resistance to nematode infection often display a reduced periparturient rise (PPR) in faecal egg counts (FEC) when compared with susceptible sheep. This trial was carried out to compare the resistance of Santa Ines, an indigenous Brazilian breed of sheep, and Ile de France ewes to natural infections by gastrointestinal nematodes, especially in the periparturient period. Twelve Santa lnes and 10 Ile de France ewes were estrus synchronized and then mated (December 2001). Lambing occurred from 30 April to 19 June 2002 and the lambs were weaned at 60 days of age. Faecal egg counts, packed cell volume (PCV), total plasma protein levels and peripheral eosinophils counts were determined from November 2001 to September 2002. To prevent deaths, individual treatment with anthelmintics was provided to ewes with FEC higher than 4000 eggs per gram (EPG) or with PCV lower than 21%. The percentage of Santa Ines ewes treated with anthelmintics was lower than that of Ile de France sheep. Eight of the 10 Ile de France ewes were treated, with one of them requiring four treatments, one requiring three treatments, and two requiring two treatments. The remaining four received a single treatment. In contrast, only 5 of the 12 Santa lnes ewes required treatment and for each this was done only once. The mean values of PCV were in the normal range in the Santa Ines ewes. In contrast, mean PCVs of Ile de France ewes reached a low of 24.5% in the second month after lambing and were significantly lower than Santa Ines 1 month before lambing (P < 0.05) and 2 months after lambing (P < 0.07). The mean plasma protein level was significantly lower in the Ile de France ewes in the second month after lambing (P < 0.01) coinciding with a reduction in PCV. The ewes of both breeds had high mean numbers of eosinophils in blood, which increased even further post-weaning when a marked reduction in FEC occurred. Haemonchus larvae were the most numerous genus in faecal cultures for both breeds followed by Trichostrongylus, Oesophagostomum and Cooperia. A periparturient rise in FEC was observed in both breeds. However, Santa Ines ewes showed a higher capacity to support the infection in an environment contaminated with large number of infective larvae of gastrointestinal nematodes. (C) 2004 Elsevier B.V. All rights reserved.

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The mature testicular vesicles of the species Pseudonannolene tocaiensis have three portions: a peripheral portion; a central portion that is typically secretory and between these two an intermediary portion, a lumen filled with spermatozoa. Both secretory and peripheral portions present the same type of cells. The ultrastructural analysis of the peripheral portion suggests it is involved in hormone synthesis. The secretory portion probably contributes to the production of spermatic fluid, compensating for the absence of male accessory glands in this species. (c) 2007 Elsevier Ltd. All rights reserved.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)National Science Foundation (NSF)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The phylogeny of Celastraceae subfamily Salacioideae (ca. 255 species in the Old and New World tropics) and tribe Lophopetaleae (ca. 29 species in southern Asia and the Austral-Pacific) was inferred using morphological characters together with plastid (matK, trnL-F) and nuclear (ITS and 26S rDNA) genes. Brassiantha, a monotypic genus endemic to New Guinea, is inferred to be more closely related to the clade of Dicarpellum (New Caledonia) and Hypsophila (Queensland, Australia) than it is to Hippocrateoideae or Salacioideae. This unambiguously supported resolution indicates that a nectary disk positioned outside the stamens has been convergently derived in these two lineages. The clade of Kokoona and Lophopetalum is resolved as more closely related to Breria and Elaeodendron than it is to Hippocrateoideae or Salacioideae. Sarawakodendron, a monotypic genus endemic to Borneo, is resolved as sister to Salacioideae. Salacioideae are inferred to have an Old World origin that was followed by a single successful radiation within Central and South America. We infer that capsular fruits are primitive within the clade of Hippocrateoideae + Sarawakodendron + Salacioideae, with berries a synapomorphy for Salacioideae. Based on the resolution of Sarawakodendron as sister to Salacioideae, we hypothesize that the filaments of Sarawakodendron arils are homologous to the spiral filaments in the mucilagenous pulp of Salacioideae.

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Background: Hyperhomocysteinemia is a major risk factor for cerebral and peripheral vascular diseases, as well as cortical and hippocampal injury, including an increased risk of dementia and cognitive impairment. Elevated serum homocysteine (Hcy) concentrations are common in patients with Parkinson's disease (PD) who have been treated with levodopa; however, physical exercises can help reduce Hcy concentrations. The aim of the present study was to compare serum Hcy levels in patients with PD who partook in regular physical exercises, sedentary PD patients, and healthy controls.Methods: Sixty individuals were enrolled in the present study across three groups: (i) 17 patients who did not partake of any type of exercise; (ii) 24 PD patients who exercised regularly; and (iii) 19 healthy individuals who did not exercise regularly. All participants were evaluated by Hoehn and Yahr scale, the Unified Parkinson's Disease Rating Scale (UPDRS) and Schwab and England scale (measure daily functionality). The serum levels of Hcy were analyzed by blood samples collected of each participant. An analysis of variance and a Tukey's post hoc test were applied to compare and to verify differences between groups. Pearson's correlation and stepwise multiple regression analyses were used to consider the association between several variables.Results: Mean plasma Hcy concentrations in individuals who exercised regularly were similar to those in the healthy controls and significantly lower than those in the group that did not exercise at all (P = 0.000). In addition, patients who did not exercise were receiving significantly higher doses of levodopa than those patients who exercised regularly (P = 0.001). A positive relationship between levodopa dose and Hcy concentrations (R(2) = 0.27; P = 0.03) was observed in patients who did not exercise, but not in those patients who exercised regularly (R(2) = 0.023; P = 0.15).Conclusions: The results of the present study suggest that, even with regular levodopa therapy, Hcy concentrations in PD patients who exercise regularly are significantly lower than in patients who do not exercise and are similar Hcy concentrations in healthy controls.

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A maioria dos peixes da família Rivulidae são popularmente conhecidos como anuais por completarem todo seu ciclo biológico em pequenos corpos de água temporários que secam obrigatoriamente em determinados períodos do ano causando a morte dos indivíduos adultos. Possuem características biológicas peculiares como pequeno porte, maturação sexual precoce, reprodução contínua, um elaborado padrão de corte e uma grande capacidade reprodutiva entre os peixes. Os rivulídeos se encontram amplamente distribuídos nas Américas do Norte, Central e Sul. Este trabalho analisou a dieta e a biologia reprodutiva de Cynopoecilus melanotaenia. Foram coletados 263 exemplares e a análise de 233 conteúdos gastrointestinais revelou uma dieta invertívora composta principalmente por microcrustáceos (Cladocera, Amphipoda e Ostracoda) e insetos imaturos (Chaoboridae, Culicidae, Syrphidae, mas principalmente larvas de Chironomidae). Foi registrada a lepidofagia na dieta dos machos. A fecundidade foi estimada pela análise de 59 pares de ovários maduros e variou entre 2 a 157 ovócitos (média, 19 ± 26[DP]). A espécie apresentou desova parcelada, uma estratégia para aumentar a chance de sobrevivência a depleções prolongadas. Este trabalho apresenta a primeira investigação sobre a biologia reprodutiva de C. melanotaenia. Os resultados encontrados sugerem a estratégia reprodutiva oportunista de C. melanotaenia e fornecem novas informações biológicas que podem contribuir para pesquisas de conservação e manutenção da espécie em seu ambiente natural.

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Spatial analysis and fuzzy classification techniques were used to estimate the spatial distributions of heavy metals in soil. The work was applied to soils in a coastal region that is characterized by intense urban occupation and large numbers of different industries. Concentrations of heavy metals were determined using geostatistical techniques and classes of risk were defined using fuzzy classification. The resulting prediction mappings identify the locations of high concentrations of Pb, Zn, Ni, and Cu in topsoils of the study area. The maps show that areas of high pollution of Ni and Cu are located at the northeast, where there is a predominance of industrial and agricultural activities; Pb and Zn also occur in high concentrations in the northeast, but the maps also show significant concentrations of Pb and Zn in other areas, mainly in the central and southeastern parts, where there are urban leisure activities and trade centers. Maps were also prepared showing levels of pollution risk. These maps show that (1) Cu presents a large pollution risk in the north-northwest, midwest, and southeast sectors, (2) Pb represents a moderate risk in most areas, (3) Zn generally exhibits low risk, and (4) Ni represents either low risk or no risk in the studied area. This study shows that combining geostatistics with fuzzy theory can provide results that offer insight into risk assessment for environmental pollution.

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