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1.
Disabil Rehabil ; : 1-12, 2023 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-37431170

RESUMO

PURPOSE: The aim of this review is to assess the efficacy and safety of using heat and cold therapy for adults with lymphoedema. METHODS: A multi-database search was undertaken. Only studies which included adults with lymphoedema who were treated with heat or cold therapy reporting any outcome were included. Screening, data extraction, and assessment of bias were undertaken by a single reviewer and verified by a second. Due to the substantial heterogeneity, a descriptive synthesis was undertaken. RESULTS: Eighteen studies were included. All nine studies which assessed the effects of heat-therapy on changes in limb circumference reported a point estimate indicating some reduction from baseline to end of study. Similarly, the five studies evaluating the use of heat-therapy on limb volume demonstrated a reduction in limb volume from baseline to end-of-study. Only four studies reported adverse events of which all were deemed to be minor. Only two studies explored the effects of cold therapy on lymphoedema. CONCLUSIONS: Tentative evidence suggests heat-therapy may have some benefit in treating lymphoedema with minimal side effects. However, further high-quality randomised controlled trials are required, with a particular focus on moderating factors and assessment of adverse events.Implications for rehabilitationThis review highlights the potential benefit that heat therapy may have on reducing limb circumference and volume for adults with lymphoedema.There was no evidence that controlled localised heat therapy was unsafe.The current evidence-base is at a point where no specific clinical recommendations can be made.The use of heat therapy should only be applied as part of a methodologically robust study to treat lymphoedema.

2.
Sci Rep ; 10(1): 8498, 2020 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-32444633

RESUMO

With efforts to restore large mammal populations following extirpations, it is vital to quantify how they are impacted by human activities and gain insights into population dynamics in relation to conservation goals. Our objective was to characterize cause-specific mortality of black bears (Ursus americanus) throughout their range. We first quantified cause-specific mortality for 247 black bears in one harvested and two non-harvested populations. We then simulated a small recolonizing population with and without anthropogenic mortality. Lastly, we conducted a meta-analysis of all published black bear mortality studies throughout North America (31 studies of 2630 bears). We found anthropogenic mortality was greater than natural mortality, non-harvest anthropogenic mortality (e.g. poaching, defense of property, etc.) was greater in non-harvested populations, and harvesting was one of the major causes of mortality for bears throughout their range. Our simulation indicated that removing anthropogenic mortality increased population size by an average of 23% in 15 years. We demonstrated that bears are exposed to high levels of anthropogenic mortality, and the potential for human activities to slow population growth in expanding populations. Management and conservation of wide-ranging mammals will depend on holistic strategies that integrate ecological factors with socio-economic issues to achieve successful conservation and coexistence.


Assuntos
Conservação dos Recursos Naturais , Atividades Humanas , Longevidade , Dinâmica Populacional , Ursidae/fisiologia , Animais , Feminino , Humanos , Masculino , América do Norte , Densidade Demográfica
3.
BJOG ; 127(2): 250-259, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31498547

RESUMO

OBJECTIVE: To compare the vaginal microbiota of women living with HIV (WLWH) with the vaginal microbiota of women with recurrent bacterial vaginosis (BV) and healthy women without HIV to determine if there are differences in the vaginal microbiome, what factors influence these differences, and to characterise HIV clinical parameters including viral load and CD4 count in relation to the vaginal microbiome. DESIGN: Observational cohort study. SETTING: Canada. POPULATION: Women aged 18-49 years who were premenopausal and not pregnant were recruited into three cohorts: healthy women, WLWH and women with recurrent BV. METHODS: Demographic and clinical data were collected via interviews and medical chart reviews. Vaginal swabs were collected for Gram-stain assessment and microbiome profiling using the cpn60 barcode sequence. MAIN OUTCOME MEASURES: To compare overall community composition differences, we used compositional data analysis methods, hierarchical clustering and Kruskal-Wallis tests where appropriate. RESULTS: Clinical markers such as odour and abnormal discharge, but not irritation, were associated with higher microbial diversity. WLWH with unsuppressed HIV viral loads were more likely than other groups to have non-Gardnerella-dominated microbiomes. HIV was associated with higher vaginal microbial diversity and this was related to HIV viral load, with unsuppressed women demonstrating significantly higher relative abundance of Megasphaera genomosp. 1, Atopobium vaginae and Clostridiales sp. (all P < 0.05) compared with all other groups. CONCLUSIONS: In WLWH, unsuppressed HIV viral loads were associated with a distinct dysbiotic profile consisting of very low levels of Lactobacillus and high levels of anaerobes. TWEETABLE ABSTRACT: Vaginal microbiomes in WLWH with viral load >50 copies/ml have distinct dysbiotic profiles with high levels of anaerobes.


Assuntos
Infecções por HIV/microbiologia , Infecções por HIV/virologia , Vagina/microbiologia , Vaginose Bacteriana/microbiologia , Carga Viral , Adulto , Anaerobiose , Canadá , Estudos de Coortes , Feminino , Infecções por HIV/fisiopatologia , Humanos , Pessoa de Meia-Idade , Recidiva , Vaginose Bacteriana/fisiopatologia
5.
J Appl Microbiol ; 122(3): 785-795, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27930839

RESUMO

AIMS: The purpose of this study was to identify the volatile molecules produced by the pathogenic Gram-negative bacterium Klebsiella pneumoniae (ATCC 13883) during in vitro growth using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC-TOFMS). METHODS AND RESULTS: Klebsiella pneumoniae ATCC 13883 was incubated in lysogeny broth to mid-exponential and stationary growth phases. Headspace volatile molecules from culture supernatants were concentrated using solid-phase microextraction (SPME) and analysed via GC×GC-TOFMS. Ninety-two K. pneumoniae-associated volatile molecules were detected, of which 78 (85%) were detected at both phases of growth and 14 (15%) were detected at either mid-exponential or stationary growth phases. CONCLUSIONS: This study has increased the total number of reported K. pneumoniae-associated volatile molecules from 77 to 150, demonstrating the sensitivity and resolution achieved by employing GC×GC-TOFMS for the analysis of bacterial headspace volatiles. SIGNIFICANCE AND IMPACT OF THE STUDY: This study represents an early-stage comprehensive volatile metabolomic analysis of an opportunistic bacterial pathogen. Characterizing the volatile molecules produced by K. pneumoniae during in vitro growth could provide us with a better understanding of this organisms' metabolism, an area that has not been extensively studied to date.


Assuntos
Klebsiella pneumoniae/metabolismo , Metaboloma , Cromatografia Gasosa-Espectrometria de Massas/métodos , Klebsiella pneumoniae/crescimento & desenvolvimento , Metabolômica , Microextração em Fase Sólida , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/química
6.
Theriogenology ; 80(9): 1097-103, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24054553

RESUMO

The objective of this study was to evaluate the sensitivity of a commercially available real-time polymerase chain reaction (PCR) test for the detection of Tritrichomonas fetus in individual and pooled direct preputial samples. Two samples were collected and processed once a week from nine T. fetus-infected bulls (n = 121) and placed into either an InPouch TF or 2 mL of PBS. Preputial samples were also collected into both media and PBS from 1016 other bulls. All pouches were cultured and evaluated as per manufacturer's instructions. The prepuce samples collected directly into PBS were individually evaluated using real-time PCR by a commercial diagnostic laboratory. Direct preputial samples were then randomly divided for pooling into groups of 5 and 10 samples, ensuring that every pool had one sample from a known infected bull before testing using real-time PCR. Sensitivity was estimated for culture and real-time PCR of the 121 direct and culture-enriched individual samples from nine infected bulls. There were no differences (P = 0.12) among the sensitivity estimates for culture, 95.0% (95% confidence interval [CI]: 89.6%-97.7%); real-time PCR of culture-enriched samples, 95.9% (95% CI: 90.7-98.2); and direct preputial samples, 90.1% (95% CI: 83.5-94.2). There was also no significant difference (P = 0.08) between the sensitivity of real-time PCR for direct preputial samples in 110 pools of 5 (83.6%, 95% CI: 75.6-89.4) or 10 samples (77.3%, 95% CI: 68.6-84.1). The use of three sequential direct samples, collected in PBS at weekly intervals and tested by real-time PCR, increased the sensitivity to 100% for pools of 5 and 96% for pools of 10. In conclusion, direct preputial samples collected in PBS and tested by real-time PCR individually have comparable sensitivity to culture and real-time PCR in enriched samples. The use of pooled direct preputial samples appears to be relatively sensitive. However, this strategy requires repeated sampling to optimize sensitivity. Real-time PCR testing of preputial samples collected directly into PBS with the option of pooling would decrease the cost associated with screening bulls, and increase the feasibility of large epidemiological studies and active surveillance.


Assuntos
Infecções Protozoárias em Animais/diagnóstico , Tritrichomonas foetus/genética , Animais , Bovinos , Masculino , Reação em Cadeia da Polimerase em Tempo Real , Sensibilidade e Especificidade
7.
Parasitology ; 140(9): 1133-7, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23714582

RESUMO

In 2009, a haplotype closely related to European strains of Echinococcus multilocularis was detected in a dog from the Quesnel region of British Columbia, Canada. We now report the establishment of this same haplotype in 7 coyotes (Canis latrans) trapped within 40 km of Quesnel, BC. In addition, 3 coyotes and 1 red fox (Vulpes vulpes) harboured adult cestodes morphologically compatible with that of E. multilocularis (overall prevalence 33% in 33 carnivores). None of 156 potential intermediate hosts, including 131 representatives of two highly suitable rodent species, Peromyscus maniculatus and Microtus pennsylvanicus, trapped from a region 120-210 km south of Quesnel were infected. This report confirms the establishment and local transmission of a European-type strain of E. multilocularis (the causative agent of human alveolar hydatid disease), in wildlife in a forested region of North America where this cestode had not been previously detected, with significance for public and animal health.


Assuntos
Coiotes , Equinococose/veterinária , Echinococcus multilocularis/isolamento & purificação , Raposas , Doenças dos Roedores/epidemiologia , Animais , Animais Selvagens , Colúmbia Britânica/epidemiologia , Cães , Equinococose/epidemiologia , Equinococose/transmissão , Echinococcus multilocularis/classificação , Echinococcus multilocularis/fisiologia , Doenças Endêmicas/veterinária , Florestas , Haplótipos , Humanos , Prevalência , Saúde Pública , Doenças dos Roedores/transmissão , Roedores
8.
J Appl Microbiol ; 114(6): 1671-86, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23448257

RESUMO

AIMS: To describe the diversity and metabolic potential of microbial communities in uranium mine tailings characterized by high pH, high metal concentration and low permeability. METHODS AND RESULTS: To assess microbial diversity and their potential to influence the geochemistry of uranium mine tailings using aerobic and anaerobic culture-based methods, in conjunction with next generation sequencing and clone library sequencing targeting two universal bacterial markers (the 16S rRNA and cpn60 genes). Growth assays revealed that 69% of the 59 distinct culturable isolates evaluated were multiple-metal resistant, with 15% exhibiting dual-metal hypertolerance. There was a moderately positive correlation coefficient (R = 0·43, P < 0·05) between multiple-metal resistance of the isolates and their enzyme expression profile. Of the isolates tested, 17 reduced amorphous iron, 22 reduced molybdate and seven oxidized arsenite. Based on next generation sequencing, tailings depth was shown to influence bacterial community composition, with the difference in the microbial diversity of the upper (0-20 m) and middle (20-40 m) tailings zones being highly significant (P < 0·01) from the lower zone (40-60 m) and the difference in diversity of the upper and middle tailings zone being significant (P < 0·05). Phylotypes closely related to well-known sulfate-reducing and iron-reducing bacteria were identified with low abundance, yet relatively high diversity. CONCLUSIONS: The presence of a population of metabolically-diverse, metal-resistant micro-organisms within the tailings environment, along with their demonstrated capacity for transforming metal elements, suggests that these organisms have the potential to influence the long-term geochemistry of the tailings. SIGNIFICANCE AND IMPACT OF THE STUDY: This study is the first investigation of the diversity and functional potential of micro-organisms present in low permeability, high pH uranium mine tailings.


Assuntos
Bactérias/classificação , Mineração , Urânio , Bactérias/isolamento & purificação , Bactérias/metabolismo , Biodiversidade , Biotransformação , Concentração de Íons de Hidrogênio , Ferro/metabolismo , Metais/toxicidade , Dados de Sequência Molecular , Permeabilidade , Filogenia , RNA Ribossômico 16S/genética , Cloreto de Sódio/toxicidade
9.
Environ Sci Technol ; 44(11): 4184-90, 2010 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-20504046

RESUMO

The influence of bacterial flagella on cell transport has been examined using three Salmonella enterica serovars with different motility phenotypes. Both a packed bed (PB) column and radial stagnation point flow system (RSPF) were employed to investigate bacterial deposition kinetics onto quartz over a range of conditions. The aim of this study was to better understand the role of motility on the deposition behavior of Salmonella, an important food- and waterborne pathogen. In both the PB column and RSPF systems, flagellated strains showed higher deposition, indicating the nonmotile cells can be transported further than the motile. At late-exponential growth phase, the deposition of the functional flagellated motile strain was enhanced, much more so than the dysfunctionally flagellated nonmotile and nonflagellated strains, highlighting the role of flagellar motion in cellular deposition and retention through available pore spaces and irregularities on quartz surfaces.


Assuntos
Flagelos/fisiologia , Salmonella enterica/fisiologia , Flagelos/ultraestrutura , Cinética , Microscopia Eletrônica de Varredura , Salmonella enterica/crescimento & desenvolvimento
10.
Benef Microbes ; 1(2): 197-207, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21831757

RESUMO

The effects of diets supplemented with either chickpea or its main oligosaccharide raffinose on the composition of the faecal microbial community were examined in 12 healthy adults (18-65 years) in a randomised crossover intervention study. Subjects consumed their usual diet supplemented with soups and desserts that were unfortified, or fortified with either 200 g/d of canned chickpeas or 5 g/d of raffinose for 3 week periods. Changes in faecal bacterial populations of subjects were examined using 16S rRNA-based terminal restriction fragment length polymorphisms (T-RFLP) and clone libraries generated from the diet pools. Classification of the clone libraries and T-RFLP analysis revealed that Faecalibacterium prausnitzii, reported to be an efficient butyrate producer and a highly metabolically active bacterium in the human intestinal microbiota, was more abundant in the raffinose diet and the chickpea diet compared to the control diet. However, no significant difference was observed in the faecal total short chain fatty acid concentration or in the levels of the components (butyrate, acetate and propionate) with the chickpea diet or the raffinose diet compared to the control diet. Bifidobacterium species were detected by T-RFLP in all three diet groups and quantitative real-time PCR (qPCR) analysis showed a marginal increase in 16S rRNA gene copies of Bifidobacterium with the raffinose diet compared to control (P>0.05). The number of individuals showing TRFs for the Clostridium histolyticum - Clostridum lituseburense groups, which include pathogenic bacteria species and putrefactive bacteria, were lower in the chickpea diet compared to the other two treatments. Diet appeared to affect colonisation by a high ammonia-producing bacterial isolate which was detected in 83%, 92% and 42% of individuals in the control, raffinose and chickpea groups, respectively. Our results indicate that chickpea and raffinose have the potential to modulate the intestinal microbial composition to promote intestinal health in humans.


Assuntos
Bactérias/classificação , Bactérias/isolamento & purificação , Biodiversidade , Cicer , Dieta/métodos , Fezes/microbiologia , Rafinose/administração & dosagem , Adulto , Bactérias/genética , Análise por Conglomerados , Estudos Cross-Over , DNA Bacteriano/genética , DNA Ribossômico/genética , Ácidos Graxos Voláteis/análise , Fezes/química , Humanos , Filogenia , Polimorfismo de Fragmento de Restrição , RNA Ribossômico 16S/genética
11.
J Fish Dis ; 32(12): 1007-16, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19573134

RESUMO

A bacterium was isolated from the mid-gut of healthy black tiger shrimp, Penaeus monodon, based on a large zone of inhibition in mixed culture on solid medium. The isolate was a Gram-positive, motile spore former, with an optimum pH range for growth in tryptone soya broth containing 2% NaCl of between pH 6 and 9. The bacterium was highly salt tolerant with concentrations between 0% and 8% having no detrimental effect on growth. The isolate was identified as Bacillus pumilus based on physiological capabilities using the API50CHB and Biolog systems. Amplification and sequencing of the 16S rRNA gene followed by phylogenetic analysis confirmed its identity. The Bacillus pumilus isolate was strongly inhibitory against the marine bacterial pathogens Vibrio alginolyticus, V. mimicus and V. harveyi, and weakly inhibitory against V. parahaemolyticus in cross-streaking assays on solid medium. The organism was marginally self-inhibitory, and inhibited B. licheniformis and B. subtilis. The suitability of the B. pumilus isolate for use as a probiotic in farmed shrimp was further supported by the absence of any of the known B. cereus enterotoxin genes. Based on these in vitro results, in vivo safety and efficacy trials are underway to determine suitability of the novel strain as a commercial probiotic.


Assuntos
Antibiose/fisiologia , Bacillus/fisiologia , Penaeidae/microbiologia , Probióticos , Animais , Bacillus/genética , Bacillus/crescimento & desenvolvimento , Bacillus/isolamento & purificação , Pesqueiros , Intestinos/microbiologia , Biologia Marinha , RNA Ribossômico 16S/genética , Tolerância ao Sal , Vibrio/crescimento & desenvolvimento
12.
Vet Pathol ; 46(2): 269-72, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19261638

RESUMO

Severe destructive polyarthropathy with fibrillation and erosion of articular cartilage, deformation of articular surfaces, and proliferation of periarticular soft tissue was diagnosed in 5 bovine fetuses aborted in the last trimester. There was involvement of a single coxofemoral joint in 2 fetuses, both elbows, and a stifle in 1, both stifles and tarsal joints in another, and, in the most severely affected fetus, both hips, stifles, and shoulders as well as 1 carpus. In affected joints, the articular cartilage was irregularly reduced in thickness and contained fibrovascular tissue and, in some cases, inflammatory cells and fibrin. Four of 5 fetuses had microscopic placentitis; all had mild lymphoplasmacytic conjunctivitis. Ureaplasma spp. was identified in 4 cases by polymerase chain reaction or culture. Fetal arthropathy and Ureaplasma diversum-associated joint pathology have not been previously reported in the veterinary literature; however, other Ureaplasma spp. are known to cause reproductive disease and arthritis in humans.


Assuntos
Feto Abortado/microbiologia , Aborto Animal/microbiologia , Doenças dos Bovinos/microbiologia , Artropatias/veterinária , Infecções por Ureaplasma/veterinária , Animais , Bovinos , Doenças dos Bovinos/patologia , Feminino , Artropatias/microbiologia , Artropatias/patologia , Doenças Placentárias/microbiologia , Doenças Placentárias/veterinária , Gravidez , Infecções por Ureaplasma/microbiologia , Infecções por Ureaplasma/patologia
13.
Philos Trans A Math Phys Eng Sci ; 365(1854): 1213-26, 2007 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-17293338

RESUMO

The Swift X-ray Telescope (XRT) has discovered that flares are quite common in early X-ray afterglows of gamma-ray bursts (GRBs), being observed in roughly 50% of afterglows with prompt follow-up observations. The flares range in fluence from a few per cent to approximately 100% of the fluence of the prompt emission (the GRB). Repetitive flares are seen, with more than four successive flares detected by the XRT in some afterglows. The rise and fall times of the flares are typically considerably smaller than the time since the burst. These characteristics suggest that the flares are related to the prompt emission mechanism, but at lower photon energies. We conclude that the most likely cause of these flares is late-time activity of the GRB central engine.

14.
Phys Rev Lett ; 97(10): 106804, 2006 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-17025844

RESUMO

Graphene has an unusual low-energy band structure with four chiral bands and half-quantized and quantized Hall effects that have recently attracted theoretical and experimental attention. We study the Fermi energy and disorder dependence of its spin Hall conductivity sigma(xy)(SH). In the metallic regime we find that vertex corrections enhance the intrinsic spin Hall conductivity and that skew scattering can lead to sigma(xy)(SH) values that exceed the quantized ones expected when the chemical potential is inside the spin-orbit induced energy gap. We predict that large spin Hall conductivities will be observable in graphene even when the spin-orbit gap does not survive disorder.

15.
Leukemia ; 20(10): 1809-18, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16932348

RESUMO

Among the topoisomerase (topo) II isozymes (alpha and beta), topo IIbeta has been suggested to regulate differentiation. In this study, we examined the role of topo IIbeta in all-trans retinoic acid (ATRA)-induced differentiation of myeloid leukemia cell lines. Inhibition of topo IIbeta activity or downregulation of protein expression enhanced ATRA-induced differentiation/growth arrest and apoptosis. ATRA-induced apoptosis in topo IIbeta-deficient cells involved activation of the caspase cascade and was rescued by ectopic expression of topo IIbeta. Gene expression profiling led to the identification of peroxiredoxin 2 (PRDX2) as a candidate gene that was downregulated in topo IIbeta-deficient cells. Reduced expression of PRDX2 validated at the mRNA and protein level, in topo IIbeta-deficient cells correlated with increased accumulation of reactive oxygen species (ROS) following ATRA-induced differentiation. Overexpression of PRDX2 in topo IIbeta-deficient cells led to reduced accumulation of ROS and partially reversed ATRA-induced apoptosis. These results support a role for topo IIbeta in survival of ATRA-differentiated myeloid leukemia cells. Reduced expression of topo IIbeta induces apoptosis in part by impairing the anti-oxidant capacity of the cell owing to downregulation of PRDX2. Thus, suppression of topo IIbeta and/or PRDX2 levels in myeloid leukemia cells provides a novel approach for improving ATRA-based differentiation therapy.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , DNA Topoisomerases Tipo II/metabolismo , Proteínas de Ligação a DNA/metabolismo , Leucemia Mieloide/metabolismo , Tretinoína/farmacologia , Apoptose/fisiologia , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/fisiologia , Divisão Celular/efeitos dos fármacos , Divisão Celular/fisiologia , DNA Topoisomerases Tipo II/genética , Proteínas de Ligação a DNA/antagonistas & inibidores , Proteínas de Ligação a DNA/genética , Dicetopiperazinas , Regulação para Baixo/efeitos dos fármacos , Regulação para Baixo/fisiologia , Inibidores Enzimáticos/farmacologia , Regulação Enzimológica da Expressão Gênica , Regulação Leucêmica da Expressão Gênica , Células HL-60 , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Humanos , Leucemia Mieloide/patologia , Leucemia Mieloide/fisiopatologia , Peroxidases/genética , Peroxidases/metabolismo , Peroxirredoxinas , Piperazinas/farmacologia , RNA Mensageiro/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Inibidores da Topoisomerase II
16.
Nature ; 437(7060): 851-4, 2005 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-16208363

RESUMO

Gamma-ray bursts (GRBs) come in two classes: long (> 2 s), soft-spectrum bursts and short, hard events. Most progress has been made on understanding the long GRBs, which are typically observed at high redshift (z approximately 1) and found in subluminous star-forming host galaxies. They are likely to be produced in core-collapse explosions of massive stars. In contrast, no short GRB had been accurately (< 10'') and rapidly (minutes) located. Here we report the detection of the X-ray afterglow from--and the localization of--the short burst GRB 050509B. Its position on the sky is near a luminous, non-star-forming elliptical galaxy at a redshift of 0.225, which is the location one would expect if the origin of this GRB is through the merger of neutron-star or black-hole binaries. The X-ray afterglow was weak and faded below the detection limit within a few hours; no optical afterglow was detected to stringent limits, explaining the past difficulty in localizing short GRBs.

17.
Science ; 309(5742): 1833-5, 2005 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-16109845

RESUMO

Gamma-ray burst (GRB) afterglows have provided important clues to the nature of these massive explosive events, providing direct information on the nearby environment and indirect information on the central engine that powers the burst. We report the discovery of two bright x-ray flares in GRB afterglows, including a giant flare comparable in total energy to the burst itself, each peaking minutes after the burst. These strong, rapid x-ray flares imply that the central engines of the bursts have long periods of activity, with strong internal shocks continuing for hundreds of seconds after the gamma-ray emission has ended.

18.
Nature ; 436(7053): 985-8, 2005 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-16107840

RESUMO

'Long' gamma-ray bursts (GRBs) are commonly accepted to originate in the explosion of particularly massive stars, which give rise to highly relativistic jets. Inhomogeneities in the expanding flow result in internal shock waves that are believed to produce the gamma-rays we see. As the jet travels further outward into the surrounding circumstellar medium, 'external' shocks create the afterglow emission seen in the X-ray, optical and radio bands. Here we report observations of the early phases of the X-ray emission of five GRBs. Their X-ray light curves are characterised by a surprisingly rapid fall-off for the first few hundred seconds, followed by a less rapid decline lasting several hours. This steep decline, together with detailed spectral properties of two particular bursts, shows that violent shock interactions take place in the early jet outflows.

19.
J Vet Diagn Invest ; 17(2): 194-7, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15825505

RESUMO

A young, partially blind Holstein steer was affected by mild cerebral atrophy. Formalin-fixed cerebral gray matter was diffusely yellow brown. Microscopically, there were eosinophilic, autofluorescent granules primarily in the cytoplasm of cerebral neurons. There was also extensive retinal atrophy with complete loss of the rod and cone layers. Ultrastructural examination of affected cerebral neurons revealed a mixture of granular osmiophilic and lamellar patterns in the cytoplasmic storage bodies. This suggests the existence of neuronal ceroid-lipofuscinosis in the Holstein breed.


Assuntos
Doenças dos Bovinos/patologia , Lipofuscinoses Ceroides Neuronais/veterinária , Degeneração Retiniana/veterinária , Telencéfalo/patologia , Animais , Atrofia/veterinária , Cegueira/etiologia , Cegueira/veterinária , Bovinos , Doenças dos Bovinos/etiologia , Doenças dos Bovinos/fisiopatologia , Imuno-Histoquímica/veterinária , Masculino , Lipofuscinoses Ceroides Neuronais/patologia , Lipofuscinoses Ceroides Neuronais/fisiopatologia , Neurônios/patologia , Neurônios/ultraestrutura , Degeneração Retiniana/etiologia , Degeneração Retiniana/patologia , Telencéfalo/fisiopatologia
20.
Vet Pathol ; 38(6): 715-20, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11732808

RESUMO

Streptozocin (STZ) induces diabetes mellitus in sheep and pigs. To test the effect of STZ in cattle, cows were given 75-150 mg STZ per kilogram of body weight. Cows receiving 150 mg/kg required euthanasia within 24 hours after infusion because of the severe systemic effects of STZ. Seven cows receiving doses of < or = 100 mg/kg had mild to marked decrease in islet immunoreactivity for insulin and in pancreatic islet density and mild to severe tubulointerstitial nephritis. Two cows receiving 75 and 85 mg/kg STZ regained their ability to produce insulin and return blood glucose to basal levels. One cow given 100 mg/kg STZ developed insulin insufficiency consistent with type I diabetes mellitus. These findings demonstrate the susceptibility of the bovine pancreas to STZ: however, severe systemic complications were encountered. Alternative dosages and methodologies should be considered in future attempts to induce diabetes in cattle using STZ.


Assuntos
Doenças dos Bovinos/patologia , Diabetes Mellitus Experimental/patologia , Modelos Animais de Doenças , Animais , Glicemia/metabolismo , Bovinos , Doenças dos Bovinos/metabolismo , Diabetes Mellitus Experimental/metabolismo , Feminino , Teste de Tolerância a Glucose/veterinária , Imuno-Histoquímica/veterinária , Insulina/metabolismo , Pâncreas/efeitos dos fármacos , Pâncreas/patologia , Estreptozocina
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