927 resultados para strategy of development
Resumo:
S100A8 (also known as CP10 or MRP8) was the first member of the S100 family of calcium-binding proteins shown to be chemotactic for myeloid cells. The gene is expressed together with its dimerization partner S100A9 during myelopoiesis in the fetal liver and in adult bone marrow as well as in mature granulocytes. In this paper we show that S100A8 mRNA is expressed without S100A9 mRNA between 6.5 and 8.5 days postcoitum within fetal cells infiltrating the deciduum in the vicinity of the ectoplacental cone. Targeted disruption of the S100A8 gene caused rapid and synchronous embryo resorption by day 9.5 of development in 100% of homozygous null embryos. Until this point there was no evidence of developmental delay in S100A8(-/-) embryos and decidualization was normal. The results of PCR genotyping around 7.5-8.5 days postcoitum suggest that the null embryos are infiltrated with maternal cells before overt signs of resorption. This work is the first evidence for nonredundant function of a member of the S100 gene family and implies a role in prevention of maternal rejection of the implanting embryo. The S100A8 null provides a new model for studying fetal-maternal interactions during implantation.
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Despite several studies on adult amphibians, only larvae of the striped marsh frog (Limnodynastes peronii) have been reported to possess the ability to compensate for the effects of cool temperature on locomotor performance by thermal acclimation. In this study, we investigated whether this thermal acclimatory ability is shared by adult L. peronii. We exposed adult L. peronii to either 18 or 30 degrees C for 8 weeks and tested their swimming and jumping performance at six temperatures between 8 and 35 degrees C. Acute changes in temperature affected both maximum swimming and jumping performance, however there was no difference between the two treatment groups in locomotor performance between 8 and 30 degrees C. Maximum swimming velocity of both groups increased from 0.62 +/- 0.02 at 8 degrees C to 1.02 +/- 0.03 m s(-1) at 30 degrees C, while maximum jump distance increased from similar to 20 to > 60 cm over the same temperature range. Although adult L. peronii acclimated to 18 degrees C failed to produce a locomotor response at 35 degrees C, this most likely reflected a change in thermal tolerance limits with acclimation rather than modifications in the locomotor system. As all adult amphibians studied to date are incapable of thermally acclimating locomotor performance, including adults of L. peronii, this acclimatory capacity appears to be absent from the adult stage of development. (C) 2000 Elsevier Science Inc. All rights reserved.
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Visual system abnormalities are commonly encountered in the fetal alcohol syndrome although the level of exposure at which they become manifest is uncertain. In this study we have examined the effects of either low (ETLD) or high dose (ETHD) ethanol, given between postnatal days 4-9, on the axons of the rat optic nerve. Rats were exposed to ethanol vapour in a special chamber for a period of 3 h per day during the treatment period. The blood alcohol concentration in the ETLD animals averaged similar to 171 mg/dl and in the ETHD animals similar to 430 mg/dl at the end of the treatment on any given day. Groups of 10 and 30-d-old mother-reared control (MRC), separation control (SC), ETLD and ETHD rats were anaesthetised with an intraperitoneal injection or ketamine and xylazine, and killed by intracardiac perfusion with phosphate-buffered glutaraldehyde. In the 10-d-old rat optic nerves there was a total of similar to 145000-165000 axons in MRC, SC and ETLD animals. About 4 % of these fibres were myelinated. The differences between these groups were not statistically significant. However, the 10-d-old ETHD animals had only about 75000 optic nerve axone (P < 0.05) of which about 2.8 % were myelinated. By 30 d of age there was a total of between 75000 90000 optic nerve axons, irrespective of the group examined. The proportion of axons which were myelinated at this age was still significantly lower (P < 0.001) in the ETHD animals (similar to 77 %) than in the other groups (about 98 %). It is concluded that the normal stages of development and maturation of the rat optic nerve axons, as assessed in this study, can be severely compromised by exposure to a relatively high (but not low) dose of ethanol between postnatal d 4 and 9.
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This paper uses a fully operational inter-regional computable general equilibrium (CGE) model implemented for the Brazilian economy, based on previous work by Haddad and Hewings, in order to assess the likely economic effects of road transportation policy changes in Brazil. Among the features embedded in this framework, modelling of external scale economies and transportation costs provides an innovative way of dealing explicitly with theoretical issues related to integrated regional systems. The model is calibrated for 109 regions. The explicit modelling of transportation costs built into the inter-regional CGE model, based on origin-destination flows, which takes into account the spatial structure of the Brazilian economy, creates the capability of integrating the inter-regional CGE model with a geo-coded transportation network model enhancing the potential of the framework in understanding the role of infrastructure on regional development. The transportation model used is the so-called Highway Development and Management, developed by the World Bank, implemented using the software TransCAD. Further extensions of the current model specification for integrating other features of transport planning in a continental industrialising country like Brazil are discussed, with the goal of building a bridge between conventional transport planning practices and the innovative use of CGE models. In order to illustrate the analytical power of the integrated system, the authors present a set of simulations, which evaluate the ex ante economic impacts of physical/qualitative changes in the Brazilian road network (for example, a highway improvement), in accordance with recent policy developments in Brazil. Rather than providing a critical evaluation of this debate, they intend to emphasise the likely structural impacts of such policies. They expect that the results will reinforce the need to better specifying spatial interactions in inter-regional CGE models.
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Inflorescence and floral development of three species of Indigofera (Leguminosae-Papilionoideae), I. lespedezioides, I. spicata, and I. suffruticosa, were investigated and compared with that of other papilionoid groups, especially with members of the recently circumscribed Millettioid clade, which was merged as sister to Indigofereae in a recent cladistic analysis. Although Indigofera is a genus of special interest, because of its great richness in species and its economic importance, few studies have been made of floral development in the genus or in Indigofereae as a whole. Flower buds and inflorescences were analysed at several stages of development in the three species. Our results confirmed that Indigofera species bear a usual inflorescence type among legumes, the raceme, which comprises flowers initiated in acropetal succession, each with a subtending bract and no bracteoles initiated. The inception of the floral organs is as follows: sepals (5), petals (5), carpel (1), outer stamens (5), and, finally, inner stamens (5). Organ initiation in the sepal, petal, and both stamen whorls is unidirectional, from the abaxial side; the carpel cleft is adaxial. The vexillum is larger than other petals at maturity, covering the keels, which are fused edge-to-edge. Nine filaments are fused to form an adaxially open sheath, and the adaxial stamen of the inner whorl remains free (diadelphous androecium) in the mid-stage of development. Most of the infra-generic differences occurred in the later stages of development. Data on floral development in Indigofera obtained here were also compared with those from other members of Papilionoideae. This comparison showed that the early expression of zygomorphy is shared with other members of the Millettioid clade but is rarely found in other papilionoids, corresponding to a hypothetically morphological synapomorphy in the pair Indigoferae plus millettioids.
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This work characterized the population structure of the hermit crab Loxopagurus loxochelis (Moreira, 1901) in terms of size frequency distribution and sex ratio. Specimens were collected monthly, over a period of one year (from July 2002 to June 2003), in seven transects (from 5 to 35 m of depth) using fishing boat equipped with two double-rig trawl nets, in Caraguatatuba and Ubatuba regions (state of Sao Paulo, Brazil). A total of 366 hermit crabs were collected in Caraguatatuba [222 males (60.65%), 114 non-ovigerous females (31.15%) and 30 ovigerous females (8.20%)] and 126 hermit crabs in Ubatuba [81 males (64.28%), 38 non-ovigerous females (30.16%) and seven ovigerous females (5.56%)]. In Caraguatatuba the highest incidence of ovigerous females occurred during winter (July 2002), whereas in Ubatuba, the number was incipient. The cephalothoracic shield length ranged from 2.0 to 7.9mm (5.29 +/- 0.96mm) in Caraguatatuba, and from 2.7 to 7.5mm (5.32 +/- 0.95mm) in Ubatuba. The mean size of males was significantly larger than the mean size of females in both regions. Overall sex ratio was in favor of males (1.54:1 in Caraguatatuba and 1.9:1 in Ubatuba). Sexual dimorphism was recorded to L. loxochelis by the presence of males in the largest size classes, following the standard pattern observed in Decapoda. There was an unimodal size distribution for both sexes, with normal distributions in both regions. The higher number of males in relation to females may indicate the existence of different growth and mortality rates between the sexes. Despite of the different geomorphologic characteristics between Caraguatatuba and Ubatuba regions, the dynamics of development was similar for both populations.
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This paper describes algorithms that can identify patterns of brain structure and function associated with Alzheimer's disease, schizophrenia, normal aging, and abnormal brain development based on imaging data collected in large human populations. Extraordinary information can be discovered with these techniques: dynamic brain maps reveal how the brain grows in childhood, how it changes in disease, and how it responds to medication. Genetic brain maps can reveal genetic influences on brain structure, shedding light on the nature-nurture debate, and the mechanisms underlying inherited neurobehavioral disorders. Recently, we created time-lapse movies of brain structure for a variety of diseases. These identify complex, shifting patterns of brain structural deficits, revealing where, and at what rate, the path of brain deterioration in illness deviates from normal. Statistical criteria can then identify situations in which these changes are abnormally accelerated, or when medication or other interventions slow them. In this paper, we focus on describing our approaches to map structural changes in the cortex. These methods have already been used to reveal the profile of brain anomalies in studies of dementia, epilepsy, depression, childhood and adult-onset schizophrenia, bipolar disorder, attention-deficit/ hyperactivity disorder, fetal alcohol syndrome, Tourette syndrome, Williams syndrome, and in methamphetamine abusers. Specifically, we describe an image analysis pipeline known as cortical pattern matching that helps compare and pool cortical data over time and across subjects. Statistics are then defined to identify brain structural differences between groups, including localized alterations in cortical thickness, gray matter density (GMD), and asymmetries in cortical organization. Subtle features, not seen in individual brain scans, often emerge when population-based brain data are averaged in this way. Illustrative examples are presented to show the profound effects of development and various diseases on the human cortex. Dynamically spreading waves of gray matter loss are tracked in dementia and schizophrenia, and these sequences are related to normally occurring changes in healthy subjects of various ages. (C) 2004 Published by Elsevier Inc.
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Little attention has been given to the contextual politics of service delivery reforms. By focusing on cases of reform in the healthcare sector and, to a lesser extent, in the main policies in the social service sector in India, Mexico and Brazil, this article explores two dimensions of analysis which have enormous relevance in understanding the reach and effectiveness of service delivery reforms: (1) the historical timing of reforms and sectorial baselines, and (2) the degree and institutional locus of local discretion in policy. Findings show that depending on both dimensions, there is an extraordinary variation as to the degree, interests involved and meaning of changes which, in theory, correspond to these countries` commitment to the service delivery reforms, However, consideration of the contextual politics is relevant not for the sake of diversity but for the similarities that this diversity reveals, pointing to underlying analytic dimensions that receive attention in this article.
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Aims: We evaluated the effect of botulinum toxin type A (BTX-A) injections in the trigone on the antireflux mechanism and evaluated its short-term efficacy. Materials and Methods: Between April and December 2006, 21 patients (10 men and 11 women) were prospectively evaluated. All were incontinent due to refractory NDO and underwent detrusor injection of 300 units of BTX-A, including 50 units into the trigone. Baseline and postoperative evaluation after eight weeks included cystogram, urinary tract ultrasound and urodynamics. Results: At baseline, 20 patients had no vesicoureteral (VUR) and one had grade II unilateral VUR. Postoperative evaluation revealed no cases of de novo VUR and the patient with preinjection VUR had complete resolution of the reflux. Ultrasound showed 5 (23.8%) patients with hydronephrosis before BTX-A injection and only one (4.8%) at the followup evaluation (p=0.066). After treatment, 9 (42.8%) patients became dry, 11 (52.4%) were improved and one (4.8%) had no improvement. Improved patients received antimuscarinic treatment and 8 (38.1%) became dry, with a final total continence rate of 80.1%. Cystometric capacity increased from 271 +/- 92 to 390 +/- 1189 ml (p = 0.002), reflex volume varied from 241 +/- 96 to 323 +/- 201 ml (p = 0.020) and maximum detrusor pressure reduced from 66 +/- 39 to 38 +/- 37 cm H2O (p < 0.001). Conclusions: Our results confirm the safety of trigone injections of BTX-A in terms of development of VUR and upper urinary tract damage. Whether they are beneficial for patients with NDO or other causes of voiding dysfunction will need further studies.
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The role of physiological understanding in improving the efficiency of breeding programs is examined largely from the perspective of conventional breeding programs. Impact of physiological research to date on breeding programs, and the nature of that research, was assessed from (i) responses to a questionnaire distributed to plant breeders and physiologists, and (ii) a survey of literature abstracts. Ways to better utilise physiological understanding for improving breeding programs are suggested, together with possible constraints to delivering beneficial outcomes. Responses from the questionnaire indicated a general view that the contribution by crop physiology to date has been modest. However, most of those surveyed expected the contribution to be larger in the next 20 years. Some constraints to progress perceived by breeders and physiologists were highlighted. The survey of literature abstracts indicated that from a plant breeding perspective, much physiological research is not progressing further than making suggestions about possible approaches to selection. There was limited evidence in the literature of objective comparison of such suggestions with existing methodology, or of development and application of these within active breeding programs. It is argued in this paper that the development of outputs from physiological research for breeding requires a good understanding of the breeding program(s) being serviced and factors affecting its performance. Simple quantitative genetic models, or at least the ideas they represent, should be considered in conducting physiological research and in envisaging and evaluating outputs. The key steps of a generalised breeding program are outlined, and the potential pathways for physiological understanding to impact on these steps are discussed. Impact on breeding programs may arise through (i) better choice of environments in which to conduct selection trials, (ii) identification of selection criteria and traits for focused introgression programs, and (iii) identifying traits for indirect selection criteria as an adjunct to criteria already used. While many breeders and physiologists apparently recognise that physiological understanding may have a major role in the first area, there appears to be relatively Little research activity targeting this issue, and a corresponding bias, arguably unjustified, toward examining traits for indirect selection. Furthermore, research on traits aimed at crop improvement is often deficient because key genetic parameters, such as genetic variation in relevant breeding populations and genetic (as opposed to phenotypic) correlations with yield or other characters of economic importance, are not properly considered in the research. Some areas requiring special attention for successfully interfacing physiology research with breeding are discussed. These include (i) the need to work with relevant genetic populations, (ii) close integration of the physiological research with an active breeding program, and (iii) the dangers of a pre-defined or narrow focus in the physiological research.
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Background-In the Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial, an initial strategy of coronary revascularization and optimal medical treatment (REV) compared with an initial optimal medical treatment with the option of subsequent revascularization (MED) did not reduce all-cause mortality or the composite of cardiovascular death, myocardial infarction, and stroke in patients with type 2 diabetes mellitus and stable ischemic heart disease. In the same population, we tested whether the REV strategy was superior to the MED strategy in preventing worsening and new angina and subsequent coronary revascularizations. Methods and Results-Among the 2364 men and women (mean age, 62.4 years) with type 2 diabetes mellitus, documented coronary artery disease, and myocardial ischemia, 1191 were randomized to the MED and 1173 to the REV strategy preselected in the percutaneous coronary intervention (796) and coronary artery bypass graft (377) strata. Compared with the MED strategy, the REV strategy at the 3-year follow-up had a lower rate of worsening angina (8% versus 13%; P < 0.001), new angina (37% versus 51%; P = 0.001), and subsequent coronary revascularizations (18% versus 33%; P < 0.001) and a higher rate of angina-free status (66% versus 58%; P = 0.003). The coronary artery bypass graft stratum patients were at higher risk than those in the percutaneous coronary intervention stratum, and had the greatest benefits from REV. Conclusions-In these patients, the REV strategy reduced the occurrence of worsening angina, new angina, and subsequent coronary revascularizations more than the MED strategy. The symptomatic benefits were observed particularly for high-risk patients.
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This work characterizes the effects of ambient levels of urban particulate matter (PM(2.5)) from the city of Sao Paulo on spermatogenesis using mice exposed during the embryo-fetal and/or postnatal phases of development. Parental generations (BALB/c mice) were exposed to air pollution in chambers with or without filtering PM(2.5) for 4 months. Animals were mated, and half of the 1-day-old offspring were moved between chambers, which yielded prenatal and postnatal groups. Remaining offspring comprised the non-exposed and pre+postnatal exposed groups. After 90 days, the animals were sacrificed for testis collection and weighing. Optical microscopy was used for the morphometric analyses of the cell counts, spermatogenic cycle, proliferation, and apoptosis. Prenatally exposed animals presented reduced body and testicular weight with an increased gonadosomatic index (GSI). Testicular volume also decreased, as well as the tubular diameter in testes of the same animals. Proliferation, apoptosis, and spermatogenic cycle analyses showed no significant differences among groups. However, the tubules at stage VII of pre- and postnatal animals presented a reduced number of elongated spermatids. Pre+postnatal group presented higher spermatid head retention at stages VIII-XII. These results show that ambient levels of PM(2.5) from Sao Paulo city affect spermatogenesis by damaging sperm production.
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The neotropical tick Amblyomma cajennense is a significant pest to domestic animals, the most frequently human-biting tick in South America and the main vector of Brazilian spotted fever (caused by Rickettsia rickettsii), a deadly human disease. The purpose of this study is to characterize the adult A. cajennense salivary gland transcriptome by expressed sequence tags (ESTs). We report the analysis of 1754 clones obtained from a cDNA library, which reveal mainly transcripts related to proteins involved in the hemostatic processes, especially proteases and their inhibitors. Remarkably, five types of possible serine protease inhibitors were found, including a molecule with a distinguished structure that contains repeats of the active motif of hirudin inhibitors. Besides, other components that may be active over the host immune system or acting as defensins against infecting microorganisms were also described, including a molecule similar to insect venom allergens. The conjunction of components from this transcriptome suggests a diverse strategy of A. cajennense tick during feeding, but emphasized in the coagulation system. (c) 2008 Published by Elsevier Ltd.
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Turkey coronavirus (TCoV) is a causative agent associated with poult enteritis and mortality syndrome (PEMS) in turkeys worldwide. The disease is an acute, highly contagious enteric disease that is characterized by depression, anorexia, diarrhea, and high mortality in commercial turkey flocks. The presence of TCoV in 12 intestinal-content samples, from turkey flocks aged between 10 and 104 days and exhibiting severe enteritis, was monitored during the period of 2004 to 2006. TCoV detection was accomplished by a reverse transcriptase-polymerase chain reaction (RT-PCR) through amplification of the 3` UTR region, followed by amplification of genes 3 and 5. Molecular characterization of the viruses was done through amplification of genes 3 and 5 and showed evidence of genetic similarity between them, although they differed from sequences of other TCoVs described in the literature. In relation to gene 3, samples showed a greater relationship with chicken infectious bronchitis virus (IBV), while gene 5 showed greater identity with pheasant coronavirus (PhCoV). Our results suggest that the strategy of amplification of the 3` UTR region, followed by sequencing of genes 3 and 5, has proven to be an effective means of detecting TCoV in intestinal contents.
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Menadione is a naphthoquinone used as a vitamin K source in animal feed that can generate reactive oxygen species (ROS) and cause apoptosis. Here, we examined whether menadione reduces development of preimplantation bovine embryos in a ROS-dependent process and tested the hypothesis that actions of menadione would be reduced by insulin-like growth factor-1 (IGF-1). Menadione caused a concentration-dependent decrease in the proportion of embryos that became blastocysts. All concentrations tested (1, 2.5, and 5.0 mu M) inhibited development. Treatment with 100 ng/ml IGF-1 reduced the magnitude of the anti-developmental effects of the two lowest menadione concentrations. Menadione also caused a concentration-dependent increase in the percent of cells positive for the TUNEL reaction. The response was lower for IGF-1-treated embryos. The effects of menadione were mediated by ROS because (1) the anti-developmental effect of menadione was blocked by the antioxidants dithiothreitol and Trolox and (2) menadione caused an increase in ROS generation. Treatment with IGF-1 did not reduce ROS formation in menadione-treated embryos. In conclusion, concentrations of menadione as low as 1.0 mu M can compromise development of bovine preimplantation embryos to the blastocyst stage of development in a ROS-dependent mechanism. Anti-developmental actions of menadione can be blocked by IGF-1 through effects downstream of ROS generation.