Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 74
Filtrar
Más filtros

Tipo del documento
Intervalo de año de publicación
1.
Nature ; 602(7898): 585-589, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-35197615

RESUMEN

Fast radio bursts (FRBs) are flashes of unknown physical origin1. The majority of FRBs have been seen only once, although some are known to generate multiple flashes2,3. Many models invoke magnetically powered neutron stars (magnetars) as the source of the emission4,5. Recently, the discovery6 of another repeater (FRB 20200120E) was announced, in the direction of the nearby galaxy M81, with four potential counterparts at other wavelengths6. Here we report observations that localized the FRB to a globular cluster associated with M81, where it is 2 parsecs away from the optical centre of the cluster. Globular clusters host old stellar populations, challenging FRB models that invoke young magnetars formed in a core-collapse supernova. We propose instead that FRB 20200120E originates from a highly magnetized neutron star formed either through the accretion-induced collapse of a white dwarf, or the merger of compact stars in a binary system7. Compact binaries are efficiently formed inside globular clusters, so a model invoking them could also be responsible for the observed bursts.

2.
Nature ; 577(7789): 190-194, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31907402

RESUMEN

Fast radio bursts (FRBs) are brief, bright, extragalactic radio flashes1,2. Their physical origin remains unknown, but dozens of possible models have been postulated3. Some FRB sources exhibit repeat bursts4-7. Although over a hundred FRB sources have been discovered8, only four have been localized and associated with a host galaxy9-12, and just one of these four is known to emit repeating FRBs9. The properties of the host galaxies, and the local environments of FRBs, could provide important clues about their physical origins. The first known repeating FRB, however, was localized to a low-metallicity, irregular dwarf galaxy, and the apparently non-repeating sources were localized to higher-metallicity, massive elliptical or star-forming galaxies, suggesting that perhaps the repeating and apparently non-repeating sources could have distinct physical origins. Here we report the precise localization of a second repeating FRB source6, FRB 180916.J0158+65, to a star-forming region in a nearby (redshift 0.0337 ± 0.0002) massive spiral galaxy, whose properties and proximity distinguish it from all known hosts. The lack of both a comparably luminous persistent radio counterpart and a high Faraday rotation measure6 further distinguish the local environment of FRB 180916.J0158+65 from that of the single previously localized repeating FRB source, FRB 121102. This suggests that repeating FRBs may have a wide range of luminosities, and originate from diverse host galaxies and local environments.

3.
J Environ Manage ; 262: 110313, 2020 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-32250796

RESUMEN

In an attempt to improve cost-effectiveness, it has become increasingly popular to adapt wildlife crossing structures to enable people to also use them for safe passage across roads. However, the required needs of humans and wildlife may conflict, resulting in a structure that does not actually provide the perceived improvement in cost-effectiveness, but instead a reduction in conservation benefits. For example, lighting within crossing structures for human safety at night may reduce use of the structure by nocturnal wildlife, thus contributing to barrier and mortality effects of roads rather than mitigating them. In this study, we experimentally evaluated the impact of artificial light at night on the rate of use of wildlife crossing structures, specifically underpasses, by ten insectivorous bat species groups in south-eastern Australia. We monitored bat activity before, during and after artificially lighting the underpasses. We found that bats tended to avoided lit underpasses, and only one species consistently showed attraction to the light. Artificial light at night in underpasses hypothetically increases the vulnerability of bats to road-mortality or to the barrier effect of roads. The most likely outcomes of lighting underpasses were 1. an increase in crossing rate above the freeway and a decrease under the underpasses, or 2. a reduction in crossing rate both above freeways and under the underpasses, when structures were lit. Our results corroborate those of studies on terrestrial mammals, and thus we recommend that underpasses intended to facilitate the movement of wildlife across roads should not be lit.


Asunto(s)
Quirópteros , Animales , Animales Salvajes , Humanos , Iluminación , Mamíferos , Australia del Sur
4.
Iran J Vet Res ; 25(1): 41-47, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39156799

RESUMEN

Background: Maedi-visna (MV) is a small ruminant lentiviral (SRLV) disease affecting sheep and goats, and causes pathological alterations in various organs including lungs, pulmonary lymph nodes, mammary glands, joints, and CNS. Aims: Present study was focused to detect the MV virus (MVV) nucleic acid and MVV p28 antigen in different organs of the spontaneously MVV affected sheep and goats. Methods: Total of 657 samples were collected from sheep and goats (169 blood, 136 lungs, 96 pulmonary lymph nodes, 74 brain, 54 mammary gland, 78 joints, and 50 spleen) and screened for MVV nucleic acid using nested PCR assay. Serum samples were screened for SRLV antibodies by cELISA. Immunolocalization of MVV was demonstrated by using the polyclonal antibody against p28 antigen by immunohistochemistry in lungs, lymph nodes, mammary glands, and joint tissues. Results: Out of 657 samples, 10.7% (70) were found positive for MVV. Among different organs, lungs showed highest positivity (25.7%) followed by mammary glands (14.8%), blood (9.5%), joint tissues (7.7%), brain (5.4%), and pulmonary lymph node (1.0%). SRLV antibodies were detected in 29.2% of the serum samples of both sheep and goats by cELISA. MVV p28 antigen immunostaining was observed in lungs, lymph nodes, mammary glands, and joint tissues. However, the presence of MVV p28 antigen could not be demonstrated in the brain tissues. Conclusion: The highest positivity of MVV in lung tissues indicated higher predilection of the virus in the pulmonary tissue.

6.
Indian J Lepr ; 81(2): 75-9, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-20509336

RESUMEN

The transmission of leprosy has been universally accepted to be primarily, through nasal dissemination from multibacillary patients to the susceptible persons. However, the possibility of leprosy transmission through prolonged skin contact with abraded leprous skin or through skin inoculation can not be ruled out. We report a case of development of a paucibacillary leprosy patch close to the site of a local trauma, after an interval of about 13-14 years, in a HIV positive subject. Also discussed are the various hypotheses in the aetiopathogenesis of leprosy like entry route of lepra bacilli into the body, viability of lepra bacilli in the environment and evolution of skin and nerve lesions of leprosy.


Asunto(s)
Terapia Antirretroviral Altamente Activa/efectos adversos , Infecciones por VIH/tratamiento farmacológico , VIH-1 , Síndrome Inflamatorio de Reconstitución Inmune/inducido químicamente , Lepra Dimorfa/etiología , Infecciones Oportunistas Relacionadas con el SIDA/inmunología , Infecciones por VIH/complicaciones , Infecciones por VIH/inmunología , Humanos , Lepra Dimorfa/inmunología , Lepra Dimorfa/patología , Masculino , Persona de Mediana Edad , Piel/patología
7.
Indian J Lepr ; 81(4): 205-8, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-20704077

RESUMEN

An untreated case of BL presented with clinical features of type 2 reaction (T2R) confirmed by histopathology. The case was a 18-year-old female with borderline lepromatous leprosy who developed annular vesiculobullous eruptions oversome of the pre-existing plaques on arms and upper back along with fever and severe neuritis after a short course of ofloxacin intake prescribed for urinary tract infection. In addition to the above lesions, some of the existing lesions showed acute exacerbation characterized by erythema, oedema, tenderness and vesiculobullous eruption. This can be considered as an example of leprous exacerbation as described in older literature. T2Rs are common in lepromatous leprosy and not so uncommonly are observed in borderline lepromatous leprosy. The vesiculobullous and crusted lesions developing over the existing borderline plaques, some of them presenting in an annular pattern in T2R in the form of leprous exacerbation, have been reported rarely in the literature.


Asunto(s)
Eritema Nudoso/patología , Lepra Dimorfa/patología , Lepra Lepromatosa/patología , Enfermedades Cutáneas Vesiculoampollosas/patología , Adolescente , Clofazimina/administración & dosificación , Relación Dosis-Respuesta a Droga , Quimioterapia Combinada , Eritema Nudoso/tratamiento farmacológico , Femenino , Glucocorticoides/administración & dosificación , Humanos , Leprostáticos/administración & dosificación , Lepra Dimorfa/complicaciones , Lepra Dimorfa/tratamiento farmacológico , Lepra Lepromatosa/tratamiento farmacológico , Prednisolona/administración & dosificación , Recurrencia , Piel/patología , Enfermedades Cutáneas Vesiculoampollosas/complicaciones , Enfermedades Cutáneas Vesiculoampollosas/tratamiento farmacológico , Resultado del Tratamiento
8.
Indian J Lepr ; 80(3): 275-8, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-19432358

RESUMEN

The clinical features of cutaneous sarcoidosis and leprosy are some times difficult to differentiate and there have been many reports where pulmonary sarcoidosis was treated as pulmonary tuberculosis or a case of sarcoidosis was treated with anti-leprosy multidrug therapy, before a correct diagnosis was made. So far there has been only one published case report of leprosy and sarcoidosis co-infection, where tuberculoid leprosy developed in a case of sarcoidosis, known for over a decade. We are reporting a case of dual affliction, where sarcoidosis was discovered (on routine screening) in a case of lepromatous leprosy, after administration of 2 years of multidrug therapy. The role of mycobacterial antigens (among a vast array of different animate or inanimate particles) in causation of sarcoidosis, is still speculative, as reviewed from literature.


Asunto(s)
Lepra Lepromatosa/complicaciones , Sarcoidosis/etiología , Femenino , Humanos , Persona de Mediana Edad
9.
J Commun Dis ; 40(1): 27-36, 2008 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-19127666

RESUMEN

Rabies, a disease of antiquity continues to be a major public health problem in India. Multiple factors contribute to high mortality and morbidity due to animal bites. An effective strategy for control of rabies takes into account the epidemiology of animal bites, rabies and factors influencing post exposure treatment. The study was carried out as a part of Agreement for Performance of Work (APW) from World Health Organization (WHO) during the period April 2001 to September 2002. Two sets of proformae were developed and used after field testing to interview cases of animal bites and get retrospective information about rabies cases. The study was carried out at six selected centres across the country viz. Delhi, Hyderabad, Raipur, Jamnagar, Coonoor and Rajahmundry and was co-ordinated by National Institute of Communicable Diseases (NICD), Delhi. The officials engaged in the study work were thoroughly trained in the study methodology before the start of the study itself. To maintain quality and uniformity supervisory checks were done during the survey. A total of 1357 fresh animal bite victims were interviewed (exit interview) from the anti-rabies centres (ARCs). Dog bites caused maximum morbidity (92%). Second most common biting animal was monkey (3.2%), followed by cat (1.8%), fox (0.4%) etc. Most bites (64.3%) were unprovoked bites by stray (64.7%) animals. In this study 72.4% animal bite victims were males and 47.5% were children in age group of 2-18 years. 63% had Category III exposure as per the WHO classification. Before coming to ARCs 58.5% people had washed the wound with water/soap or water alone. Some of the bite victims (10.8%) had also applied chillies, salt, turmeric powder, lime, snuff powder, paste of leaves, acid, ash given by Peer Baba (magician) etc. These practices varied from one region to another. The practice of wound washing at the ARC which is an important component of animal bite management was being practiced at only one of the six centres. Of the six centres, Rabies Immunoglobulin (RIG) was available and was being used at only two centres. The study was conducted in public sector ARCs where Nervous Tissue Vaccine (NTV) was available free of cost. All the centres were using NTV except Coonoor, which is using indigenously produced Tissue Culture Vaccine along with NTV. Analysis of 192 case records of rabies cases, from two centres, revealed that dog bites caused maximum mortality (96.9%). Nearly 40% were children below 15 years of age and 78.6% were males indicating that it is an exposure related disease. In all cases, failure to seek timely and appropriate treatment led to development of disease. This paper provides an overview of epidemiology of animal bites and retrospective information about rabies patients. There is a need to strengthen Information, Education and Communication (IEC) programme regarding merits of local wound management including "do's and don'ts". ARCs should be strengthened in terms of facilities and availability of safe and effective anti rabies immunobiologicals. There is a need to create awareness regarding epidemiology and at-home and hospital management of animal bites among the service providers and general community.


Asunto(s)
Mordeduras y Picaduras/epidemiología , Mordeduras y Picaduras/virología , Vacunas Antirrábicas/uso terapéutico , Rabia/epidemiología , Rabia/prevención & control , Adolescente , Adulto , Animales , Animales Domésticos/virología , Animales Salvajes/virología , Niño , Preescolar , Femenino , Humanos , Entrevistas como Asunto , Masculino , Vigilancia de la Población , Rabia/fisiopatología , Adulto Joven
10.
Pathol Res Pract ; 214(5): 679-685, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-29615337

RESUMEN

Epithelioid glioblastoma (e-gbm) is a recently described variant of glioblastoma (GBM) which is associated with short survival and now added as a provisional entity to WHO 2016 classification of CNStumors. About half of these tumors show characteristic BRAF-V600E mutation. However, unlike conventional GBMs, e-gbm lack specific diagnostic and prognostic markers. Hence, we aimed to molecularly characterize these tumors. An extensive review of literature was performed.In a multi-institutional effort, all the cases of glioblastoma of year 2017 were reviewed. Cases with predominant epithelioid morphology were analysed. Seven cases of e-gbm (adults:4 and pediatric: 3) were identified. Duration of symptoms varied from 2 weeks to one month. Radiologically, all cases were supratentorial, contrast enhancing with solid and cystic appearance. Majority of the cases were immunopositive for GFAP (71%), EMA (71%), S100 (71%) and vimentin (85%). All the cases showed ATRX, INI-1 and H3K27me3 expression. BRAFV600Emutation was seen in 28% of cases. TERT mutation was seen in 40% cases, while one case showed EGFR amplification. H3F3A mutations and PTEN deletions were seen in none. Although e-gbms are rare, epithelioid morphology of a CNS tumor in a young adult or children with areas of necrosis needs thorough histomorphological and genetic workup.


Asunto(s)
Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patología , Glioblastoma/genética , Glioblastoma/patología , Astrocitoma/genética , Astrocitoma/metabolismo , Astrocitoma/patología , Neoplasias Encefálicas/metabolismo , Glioblastoma/metabolismo , Humanos , Mutación/genética , Fosfohidrolasa PTEN/genética , Proteínas Proto-Oncogénicas B-raf/genética
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA