Showing papers by "University of São Paulo published in 1997"
TL;DR: In this paper, the laser power dependence of the spectra of oxides and oxyhydroxides was investigated by using Raman microscopy, and it was shown that increasing laser power causes the characteristic bands of hematite to show up in the spectrum of most of the compounds studied.
Abstract: Hematite (α-Fe2O3), magnetite (Fe3O4), wustite (FeO), maghemite (γ-Fe2O3), goethite (α-FeOOH), lepidocrocite (γ-FeOOH) and δ-FeOOH were studied by Raman microscopy. Such compounds have already been studied by Raman spectroscopy, but there are some disagreements in the reported data. Here, Raman microscopy was employed to investigate the laser power dependence of the spectra of these oxides and oxyhydroxides. Low laser power was used for the reference spectra in order to minimize the risks of spectral changes due to sample degradation. The results obtained show that increasing laser power causes the characteristic bands of hematite to show up in the spectra of most of the compounds studied whereas the hematite spectrum undergoes band broadening and band shifts. © 1997 John Wiley & Sons, Ltd.
2,569 citations
TL;DR: In this article, a new chemical evolution model for the Galaxy that assumes two main infall episodes, for the formation of the halo-thick disk and thin disk, respectively, is presented.
Abstract: We present a new chemical evolution model for the Galaxy that assumes two main infall episodes, for the formation of the halo-thick disk and thin disk, respectively. We do not try to take into account explicitly the evolution of the halo since our model is better suited for computing the evolution of the disk (thick plus thin), but we implicitly assume that the timescale for the formation of the halo was of the same order as the timescale for the formation of the thick disk. The formation of the thin disk is much longer than that of the thick disk, implying that the infalling gas forming the thin disk comes not only from the thick disk but mainly from the intergalactic medium. The timescale for the formation of the thin disk is assumed to be a function of Galactocentric distance, leading to an inside-out picture for the Galaxy's building. The model takes into account the most up-to-date nucleosynthesis prescriptions and adopts a threshold in the star formation process, which naturally produces a hiatus in the star formation rate at the end of the thick-disk phase, as suggested by recent observations. The model results are compared with an extended set of observational constraints both for the solar neighborhood and for the whole disk. Among these constraints, the tightest is the metallicity distribution of the G-dwarf stars, for which new data are now available. Our model fits these new data very well. The model also predicts the evolution of the gas mass, the star formation rate, the supernova rates, and the abundances of 16 chemical elements as functions of time and Galactocentric distance. We show that, in order to reproduce most of these constraints, a timescale of ≤1 Gyr for the (halo) thick disk and of 8 Gyr for the thin disk's formation in the solar vicinity are required. We predict that the radial abundance gradients in the inner regions of the disk (R < 1 R☉) are steeper than in the outer regions, a result confirmed by recent abundance determinations, and that the inner gradients steepen during the Galactic lifetime. The importance and the advantages of assuming a threshold gas density for the onset of the star formation process are discussed.
843 citations
TL;DR: The authors review the clinical features of Huntington's disease and analyze some genetic and pathophysiologic aspects, that can help to improve the understanding of this disorder involving the basal ganglia.
629 citations
TL;DR: There is no explanation, presently, for iron presence in the nucleus, but it certainly imposes a prooxidant trend that needs to be counterbalanced in some way, and evidence is reviewed that nuclear metallothionein plays a role in this regard.
545 citations
TL;DR: Acid-etching of dentine produces profound changes in the chemical composition and physical properties of the matrix which can influence the quality of resin-dentine bonds, their strength and perhaps their durability.
545 citations
TL;DR: In this paper, the synthesis, characterization and spectroscopic properties of the compound Eu(thenoyltrifluoroacetonate), 2(dibenzyl sulfoxide) which is highly luminescent under UV excitation are described.
389 citations
TL;DR: This article examined the evidence that the evolution of modern humans is integrally related to the development of the Upper Palaeolithic and similar technologies, and concluded that there is only a weak relationship.
Abstract: The origins and evolution of modern humans has been the dominant interest in palaeoanthropology for the last decade, and much archaeological interpretation has been structured around the various issues associated with whether humans have a recent African origin or a more ancient one. While the archaeological record has been used to support or refute various aspects of the theories, and to provide a behavioural framework for different biological models, there has been little attempt to employ the evidence of stone tool technology to unravel phylogenetic relationships. Here we examine the evidence that the evolution of modern humans is integrally related to the development of the Upper Palaeolithic and similar technologies, and conclude that there is only a weak relationship. In contrast there is a strong association between the evolution and spread of modern humans and Grahame Clark's Mode 3 technologies (the Middle Stone Age/Palaeolithic). The implications of this for the evolution of Neanderthals, the multiple pattern of human dispersals, and the nature of cognitive evolution, are considered.
374 citations
TL;DR: In this paper, an insight into the in situ FTIR spectroscopy method as applied in Electrochemistry is given, and particular aspects inherent to the electrochemical method are described in a concise form.
371 citations
TL;DR: In this article, the authors examined the aerodynamic collection characteristics of the impactor inlet and the reproducibility of the sample mass collection of a PM10 sampler and compared them with one built from the same design in the US and comparable results were obtained.
Abstract: An integral part of several International Atomic Energy Agency sponsored coordinated research programmes involving the sampling and analysis of ambient airborne particules was the development of a PM10 sampler Each participant was provided with such a sampler so that comparable samples would be obtained by each of the participating groups Thus, in order to understand the characteristics of this sampler, we undertoke several characterization studies in which we examined the aerodynamic collection characteristics of the impactor inlet and the reproducibility of the sample mass collection One of the samplers machined in Belgium was compared with one built from the same design in the US and comparable results were obtained The sampler was operated side-by-side with a commercial PM10 beta gauge and an IMPROVE-design 25 μm cut-point cyclone Although the sampler was not wind tunnel tested as required for certification as a reference sampler, it does provide a collection efficiency that generally
286 citations
TL;DR: Two patients homozygous for substitution mutations in CYP17, the gene encoding P450c17, are found, demonstrating a novel mechanism for loss of enzymatic activity.
Abstract: Human male sexual differentiation requires production of fetal testicular testosterone, whose biosynthesis requires steroid 17,20-lyase activity. Patients with putative isolated 17,20-lyase deficiency have been reported. The existence of true isolated 17,20-lyase deficiency, however, has been questioned because 17 alpha-hydroxylase and 17,20-lyase activities are catalyzed by a single enzyme, microsomal cytochrome P450c17, and because the index case of apparent isolated 17,20-lyase deficiency had combined deficiencies of both activities. We studied two patients with clinical and hormonal findings suggestive of isolated 17,20-lyase deficiency. We found two patients homozygous for substitution mutations in CYP17, the gene encoding P450c17. When expressed in COS-1 cells, the mutants retained 17 alpha-hydroxylase activity but had minimal 17,20-lyase activity. Substrate competition experiments suggested that the mutations did not alter the enzyme's substrate-binding capacity, but co-transfection of cells with P450 oxidoreductase, the electron donor used by P450c17, indicated that the mutants had a diminished ability to interact with redox partners. Computer-graphic modelling of P450c17 suggests that both mutations lie in or near the redox-partner binding site, on the opposite side of the haem from the substrate-binding pocket. These mutations alter electrostatic charge distribution in the redox-partner binding site, so that electron transfer for the 17,20-lyase reaction is selectively lost or diverted to uncoupling reactions. These are the first proven cases of isolated 17,20-lyase deficiency, and they demonstrate a novel mechanism for loss of enzymatic activity.
276 citations
TL;DR: The findings suggest that SLE patients have a lipid profile abnormality which is aggravated by disease activity and may reside in a defect of VLDL metabolism, which may increase the risk of developing coronary artery disease.
Abstract: Objective: To determine the influence of systemic lupus erythematosus (SLE), disease activity, and anticardiolipin antibodies (aCL) on lipid profile, in order to identify patients with high risk for coronary artery disease (CAD).Methods: Fasting lipid profiles were performed in 36 consecutive female SLE patients without any therapy and 30 controls. Exclusion criteria were diabetes mellitus, CAD, liver or thyroid disease, ingestion of lipid-raising drugs, serum creatinine ≥ 1.5 mg/dl, and proteinuria ≥ 0.5 g/d. Disease activity was measured by SLEDAI.Results: High levels of VLDL-C and TG and low levels of HDL-C, the 'lupus pattern', were observed in inactive SLE compared to controls (P < 0.05). Active disease enhanced this difference inducing a more striking increase in VLDL-C and TG levels and also a decrease in HDL-C and LDL-C levels compared to inactive SLE patients (P < 0.05), characterizing the 'active lupus pattern'. Moreover, a significant correlation was found between SLEDAI scores and all lipid fr...
TL;DR: It is suggested that coronary angioplasty triggers cellular activation with an inflammatory response that could contribute to restenosis and induces a significant decrease in ex vivo-stimulated neutrophil superoxide generation and aggregation.
TL;DR: EPR spin-trapping studies using N-tert-butyl-alpha-phenylnitrone indicated that the yield of thiyl radical adducts had a pH profile comparable with that found for oxygen consumption, consistent with two different pathways participating in the reaction of peroxynitrite with low-molecular-mass thiols.
Abstract: Peroxynitrite mediates the oxidation of the thiol group of both cysteine and glutathione. This process is associated with oxygen consumption. At acidic pH and a cysteine/peroxynitrite molar ratio of < or = 1.2, there was a single fast phase of oxygen consumption, which increased with increasing concentrations of both cysteine and oxygen. At higher molar ratios the profile of oxygen consumption became biphasic, with a fast phase (phase I) that decreased with increasing cysteine concentration, followed by a slow phase (phase II) whose rate of oxygen consumption increased with increasing cysteine concentration. Oxygen consumption in phase I was inhibited by desferrioxamine and 5,5-dimethyl-1-pyrroline N-oxide, but not by mannitol; superoxide dismutase also inhibited oxygen consumption in phase I, while catalase added during phase II decreased the rate of oxygen consumption. For both cysteine and glutathione, oxygen consumption in phase I was maximal at neutral to acidic pH: in contrast, total thiol oxidation was maximal at alkaline pH. EPR spin-trapping studies using N-tert-butyl-alpha-phenylnitrone indicated that the yield of thiyl radical adducts had a pH profile comparable with that found for oxygen consumption. The apparent second-order rate constants for the reactions of peroxynitrite with cysteine and glutathione were 1290 +/- 30 M-1.S-1 and 281 +/- 6 M-1.S-1 respectively at pH 5.75 and 37 degrees C. These results are consistent with two different pathways participating in the reaction of peroxynitrite with low-molecular-mass thiols: (a) the reaction of the peroxynitrite anion with the protonated thiol group, in a second-order process likely to involve a two-electron oxidation, and (b) the reaction of peroxynitrous acid, or a secondary species derived from it, with the thiolate in a one-electron transfer process that yields thiyl radicals capable of initiating an oxygen-dependent radical chain reaction.
TL;DR: The dorsal premammillary nucleus showed the most striking increase in Fos levels, and cell body-specific chemical lesions therein virtually eliminated two major components of defensive behavior but increased exploratory behavior, suggesting that this caudal hypothalamic nucleus plays a critical role in the expression of behavioral responses sometimes critical for survival of the individual.
TL;DR: In this article, the authors used ultrasonography on cows and heifers of the Nelore breed of Bos indicus cattle to study the growth of the follicle in the first and second stages of the natural or prostaglandin-induced estrous cycle.
TL;DR: In this paper, the authors used pedotransfer functions that describe the influence of soil properties and tillage on the water release curve (WRC) and the soil resistance curve (SRC).
Abstract: The least limiting water range, LLWR, is the range of soil water content within which plant growth is least limited by water potential, aeration, and mechanical resistance. Little information is available on the influence of soil property or management practice on LLWR. The LLWR calculation is based on the water release curve (WRC) and the soil resistance curve (SRC). This study tested the hypothesis that pedotransfer functions (PTF) that describe the influence of soil properties and tillage on the WRC and the SRC could be used to assess the influence of these factors on the LLWR. Thirty-two paired sampling sites were located along two parallel transects in a side by side comparison of no-till and conventional tillage. The transects crossed three soil types: Aquic Hapludalf, Psammentic Hapludalf, and Typic Hapludalf. Clay content (CLAY) varied from 5.8 to 37.4%, organic carbon (OC) varied from 9 to 39 g kg -1 , and the bulk density (D b ) varied from 0.96 to 1.71 g cm -3 . Multiple regression analyses showed that WRC was related (R 2 = 0.94) with CLAY, OC, and D b whereas the SRC was related with CLAY and OC (R 2 = 0.86). Tillage had no independent effect in either of the two functions. Values of LLWR, calculated from the PTF, varied from 0 to 0.3093 cm 3 cm -3 . The LLWR was negatively related with CLAY and D b and positively related with OC. The analyses supported the hypothesis illustrating the value of PTF in assessing the sensitivity of LLWR to soil properties.
TL;DR: Patients who have traumatic brain injuries in the presence of hypotension and receive HSD are about twice as likely to survive as those who receive standard of care.
Abstract: Background: Resuscitation with hypertonic saline/dextran (HSD) has been suggested to be efficacious in patients who have traumatic brain injury and are hypotensive. We undertook a cohort analysis of individual patient data from previous prospective randomized double-blinded trials to evaluate improvements in survival at 24 hours and discharge after initial treatment with HSD in patients who had traumatic brain injury (head region Abbreviated Injury Score ≥ 4) and hypotension (systolic blood pressure ≤ 90 mm Hg). Methods: All variables and end points were defined before initiation of data handling. Investigators were blind as to the treatment. Case report forms were received from six studies. Of these, 223 patients met the inclusion for traumatic brain injury. Comparisons between HSD and standard of care were made using stratified analysis and logistic regression to assess efficacy, confounding, and interaction. Potential confounding variables of pre-fluid treatment, Glasgow Coma Scale score (3-8 vs. 9-15), injury type, and systolic blood pressure can be considered a priori factors that were known before randomization. Effects of the various trials was also considered. Results: Treatment with HSD resulted in a survival until discharge of 37.9% (39 of 103) compared with 26.9% (32 of 119) with standard of care (p = 0.080). Using logistic regression, adjusting for trial and potential confounding variables, the treatment effect can be summarized by the odds ratio of 2.12 (p = 0.048) for survival until discharge. Conclusion: Patients who have traumatic brain injuries in the presence of hypotension and receive HSD are about twice as likely to survive as those who receive standard of care.
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TL;DR: Questiona-se a atual definicao de saude da Organizacao Mundial da Saude: "situacao de perfeito bem-estar fisico, mental e social" da pessoa, considerada ultrapassada, por visar a uma perfeicao inatingivel, atentando-se as proprias caracteristicas da personalidade.
Abstract: Objections to the present WHO (World Health Organization) definition of HEALTH, as "the state of perfect physical, mental and social well-being", are expressed. It is considered to be anachronistic, first because it aims at perfection which is unaltainelle because of distict personality characteristics. As the main support for this idea, the necessary renunciation of part of man's drive to liberty in exchange for the lesser insecurity provided by social life (Freud, Castoriadis and Mc Dougall), is groted. The validity of distinguishing between "soma", "psyche" and "society" is questioned and the concept of the "integrated man", alluding to Pierre Marty and to Freud himself is adapted, and situations are recalled in which the interaction of the three aspects mentioned above is actually evident. Finally, the notion of the quality of life, in accordance with an antipositivistic taken from Bion, point of view, is discussed, and the concept that reality is that of each human being, is adapted. This priority and the proposal to rescue subjectivism which was also observed by Foucault when he studied mental disease, leads to a last criticism of the present definition of health, based exclusively on external, objective evaluations.
01 Jan 1997
TL;DR: O questionario McGill as mentioned in this paper considered instrumentos for avaliacao da dor das dimensoes sensitiva-discriminativa, afetiva-motivacional, cognitiva-avaliativa, and cognitive-avalia-avaliation for a lingua portuguesa.
Abstract: Dor e uma experiencia multidimensional e subjetiva. O desenvolvimento de instrumentos que possibilitem a avaliacao da dor nos seus diversos aspectos, e fundamental para a compreensao do quadro algico, implementacao da terapeutica e apreciacao de sua eficacia. O questionario McGill e considerado um dos melhores instrumentos para a avaliacao das dimensoes sensitiva-discriminativa, afetiva-motivacional e cognitiva-avaliativa da dor. Apresentar proposta de sua adaptacao para a lingua portuguesa e o objetivo deste estudo.
TL;DR: Low- intensity, but not high-intensity, exercise training decreases heart rate and cardiac output and, consequently, attenuates hypertension in spontaneously hypertensive rats (SHR).
Abstract: The decrease in cardiac sympathetic tone and heart rate after low-intensity exercise training may have hemodynamic consequences in spontaneously hypertensive rats (SHR). The effects of exercise tra...
TL;DR: The essential amino acids lysine, threonine, methionine and isoleucine are synthesised in higher plants via a common pathway starting with aspartate through the regulation of the pathway, and the properties of the key enzymes described.
TL;DR: In this paper, the authors show that the dependence on the bombarding energy of the real bare potential is mostly due to the intrinsically nonlocal nature of the effective one-body interaction.
Abstract: The mean field interaction between complex quantum many-body systems (nucleus-nucleus, cluster-cluster, etc.) is still an open question in current physics research. The study of this matter is a fundamental step in the understanding of many-body dynamics. In the nucleus-nucleus case, significant progress has been achieved concerning this question during the last decade [1], as a consequence of the measurement of accurate and extensive elastic scattering data at intermediate energies. Nuclear rainbow scattering, first observed in a systems [2 ‐4] and later in light heavy ions [5 ‐ 7], probes the nucleus-nucleus potential not only at the surface region but also at smaller distances, and ambiguities in the real part of the potentials have been removed. The resulting phenomenological interactions have significant dependence upon the bombarding energies. Some theoretical models have been developed to account for this energy dependence through realistic mean field potentials. Nowadays, the most successful models seem to be those based on the DDM3Y interaction [8 ‐ 10] which is an improvement of the originally energyindependent double-folding potential [11]. But, in order to fit the data, the density- and energy-dependent DDM3Y potential needs a renormalization factor which besides being system dependent [1,12] is still slightly energy dependent [1]. In this Letter we show, by an extensive description of elastic scattering data using an optical integro-differential equation, that the dependence on the bombarding energy of the real bare potential is mostly due to the intrinsically nonlocal nature of the effective one-body interaction. The real bare potential (by bare we mean the average, mean field, interaction with no coupled channels effects) is constructed using the folding model. It contains no adjustable parameters and is energy independent. The absorptive part is taken to be a three parameters WoodsSaxon interaction. We also supply a simple approach to obtain the local-equivalent energy-dependent potential. Before we set the stage for the analysis of elastic scattering data, we first describe our theoretical model. When dealing with nonlocal interactions, one is required to solve the integro-differential equation 2 ¯ h 2
TL;DR: In this article, a collective experience of three large urban trauma centers with 510 patients (316 stab wounds, 194 gunshot wounds) who were hemodynamically stable and had no urgent indications for celiotomy was presented.
Abstract: Background Considerable skepticism still exists about the role of diagnostic laparoscopy in the evaluation of penetrating abdominal trauma. The reported experience with therapeutic laparoscopy has been limited. Methods Retrospective analysis of a collective experience from three large urban trauma centers with 510 patients (316 stab wounds, 194 gunshot wounds) who were hemodynamically stable and had no urgent indications for celiotomy. Results Laparotomy was avoided in 277 of the 510 patients (54.3%) either because of nonpenetration or insignificant findings on laparoscopy. All were discharged uneventfully after a mean hospital stay of 1.7 days. Twenty-six had successful therapeutic procedures on laparoscopy (diaphragmatic repair in 16 patients, cholecystectomy in 1 patient, hepatic repair in 6 patients, and closure of gastrotomy in 3 patients) with uneventful recovery. In the remaining 203 patients, laparotomy was therapeutic in 155. Fifty-two patients had nontherapeutic celiotomy for exclusion of bowel injuries or as mandatory laparotomy for penetrating gunshot wounds (19.7%). The overall incidence of nontherapeutic laparotomy was 10.2%. Complications from laparoscopy were minimal (10 of 510) and minor. Conclusions Laparoscopy has an important diagnostic role in stable patients with penetrating abdominal trauma. In carefully selected patients, therapeutic laparoscopy is practical, feasible, and offers all the advantages of minimally invasive surgery.
TL;DR: A patient who had delayed motor milestones, proximal weakness, premature exertional fatigue, and episodes of exercise-induced pigmenturia, and partial-complex seizures is reported, which should alert clinicians to the possibility of CoQ10 deficiency.
Abstract: Coenzyme Q10 (CoQ10) transfers electrons from complexes I and II of the mitochondrial respiratory chain to complex III. There is one published report of human CoQ10 deficiency describing two sisters with encephalopathy, proximal weakness, myoglobinuria, and lactic acidosis. We report a patient who had delayed motor milestones, proximal weakness, premature exertional fatigue, and episodes of exercise-induced pigmenturia. She also developed partial-complex seizures. Serum creatine kinase was approximately four times the upper limit of normal and venous lactate was mildly elevated. Skeletal muscle biopsy revealed many ragged-red fibers, cytochrome c oxidase-deficient fibers, and excess lipid. In isolated muscle mitochondria, impaired oxygen consumption was corrected by the addition of decylubiquinone. During standardized exercise, ventilatory and circulatory responses were compatible with a defect of oxidation-phosphorylation, which was confirmed by near-infrared spectroscopy analysis. Biochemical analysis of muscle extracts revealed decreased activities of complexes I+II and I+III, while CoQ10 concentration was less than 25% of normal. With a brief course of CoQ10 (150 mg daily), the patient reported subjective improvement. The triad of CNS involvement, recurrent myoglobinuria, and ragged-red fibers should alert clinicians to the possibility of CoQ10 deficiency.
TL;DR: This study presents data on the population density, spatial distribution, and seed dispersal ecology of Brazilnut trees at a pristine stand located within the Kayap6 Indian Area of southeastern Amazonia, Para, Brazil and suggests that, once edaphic and climatic conditions are suitable, the highly contagious spatial distiibution of Bertholletia trees at the landscape level can be largely affected by the quantitatively domiinant effect of short-distance dispersal by caviomorph rodents
Abstract: Seeds of the Brazilnut tIee (Bertholletia excelsa Humb. & Bonpl., Lecythidaceae) sus- tain one of the imiost important extractive industries in neotropical foiests. Yet little is known about the demogiaphy aind seed dispersal ecology of Bertholletia, particularly in natural stands which have inot been prevriously hai-rested. This study presents data on the population density, spatial distribution, aind seed dispersal ecology of Brazilnut trees at a pristine stand located within the Kayap6 Indian Area of southeastern Amazonia, Para, Brazil. Brazilnut trees were primarily found within groves (castaizhais) of 75 to 149 trees, with a few isolated trees in between. Although the density of trees 10 cm in diameter at breast height (hereafter, dbh) at two groves was 4.8 to 5.1 trees ha-', the overall deinsity for the entire study area of c. 950 ha was estimated at 1.3 tree ha-'. Within-gi-ove neaiest ineighbour distances averaged 21 m and weie markedly skewed towaids even shorter distances. Seed dispersal experiments uising 709 maikedl seeds indlicated that this pattern can be largely explained by the highly restricted seed shadows imparted by the main seed dispersal agents of Bertholletia at this site, the red-rumped agouti (Dasyprocta leporina). Agoutis on average scatterhoard Bertholletia seeds to an average distaince of 5 m, and rarely beyond 20 m, from seed stations. We suggest that, once edaphic and climatic conditions aie suitable, the highly contagious spatial distiibution of Ber-tholletia trees at the landscape level can be largely accouinted foi by the quantitatively domiinant effect of short-distance dispersal by caviomorph rodents, and rare events of long-distance dispersal provided by other vectors. This mechanism of grove forma- tion need not resort to untested conjectures of human dispersal and intentional planting in prehis- toric and historic times as it has often been suggested in the literature.
TL;DR: In this article, a simple isotope mixing model was used to evaluate the relative proportion of water vapour generated by plant transpiration and by soil evaporation at two sites in the Amazon basin.
Abstract: Using a simple isotope mixing model, we evaluated the relative proportion of water vapour generated by plant transpiration and by soil evaporation at two sites in the Amazon basin. Sampling was carried out at two different soil covers (forest and pasture), in a seasonal tropical rainforest at eastern Amazon where major deforestation is the result of land-use change, and compared to a less seasonal central Amazon forest. In both forests, vapour from transpiration was responsible for most, if not all, of the water vapour generated in the forest, while it could not be detected above the grassy pastures. Thus the canopy transpiration may be a major source of water vapour to the forest and perhaps to the atmosphere during the dry season. The results are discussed in relation to predictive models based on net radiation that usually are not able to distinguish between transpiration and evaporation.
TL;DR: It is concluded that moderate, transient hyperthermia, even if occurring 1 day after a 7-minute global ischemic insult, exacerbates the extent of isChemic neuronal injury.
Abstract: We investigated whether moderate, transient whole-body hyperthermia (approximately 39.6 degrees C), if imposed 1 day following a brief episode of forebrain ischemia, would affect the neuropathologic outcome. Forty-two Wistar rats were subjected to either a 5- or 7-minute period of bilateral common carotid artery occlusion plus hypotension (50 mm Hg), or to the equivalent sham procedure. Twenty-four hours later, rats of one subgroup were placed into a hyperthermic chamber containing high-intensity lamps designed to elevate rectal temperature to 39 to 40 degrees C for 3 hours. Normothermic subgroups received the same procedures, but the heating lamps were turned off. Eight days after brain ischemia or the sham procedure, brains were perfusion-fixed, and numbers of ischemic-appearing CA1 pyramidal neurons were counted. In rats with 7-minute forebrain ischemia, delayed hyperthermia increased mean numbers of ischemic neurons by 2.6- to 2.7-fold in all subsectors of area CA1 (p < 0.05, ANOVA). Delayed hyperthermia in 5-minute ischemic rats also tended to increase mean numbers of ischemic neurons (by 11-fold in lateral, 6-fold in middle, and 5-fold in medial CA1 subsectors), but these differences were not statistically significant. We conclude that moderate, transient hyperthermia, even if occurring 1 day after a 7-minute global ischemic insult, exacerbates the extent of ischemic neuronal injury.
TL;DR: Three drug treatments used to increase the release of 5-HT from terminals of the dorsal raphe nucleus enhanced inhibitory avoidance (learned fear) in the elevated T-maze, a new animal model of anxiety.
TL;DR: Compared to other New World monkeys, lion tamarins used larger home range areas and exhibited longer daily path lengths than would be predicted by group biomass alone, suggesting that this pattern of foraging and use of space may be explained by the relatively greater availability of cryptic prey and their microhabitats in forests that are flooded and/or have closed canopies.
Abstract: In this paper we describe the use of space and feeding ecology of seven groups of golden lion tamarins observed for a total of 2,164 hr in Poco das Antas Reserve, Rio de Janeiro, Brazil. Relative to habitat availability in the home ranges of these groups, lion tamarins spent more time than expected in relatively undisturbed swamp forests and less time than expected in more degraded hillside and pasture habitats. Home range area was correlated with group biomass but not group size. Golden lion tamarins fed primarily on fruits and small animal prey, but relied heavily on floral nectar during seasonal periods of relatively low fruit availability. Compared to other New World monkeys, lion tamarins used larger home range areas and exhibited longer daily path lengths than would be predicted by group biomass alone. We suggest that this pattern of foraging and use of space may be explained by the relatively greater availability of cryptic prey and their microhabitats in forests that are flooded and/or have closed canopies than in forests that are in earlier stages of succession where prey may be more susceptible to desiccation during the dry season.
TL;DR: It is concluded that the decrease in neuron density with age is accompanied by an apparent increase in the fibrous components of the myenteric ganglia.
Abstract: We have examined the number of nerve cells present in the myenteric plexus of the human large intestine using a nonhistochemical method (Giemsa) in laminar preparations of the muscularis externa in tw