RESUMEN

The Ionospheric Connections Explorer (ICON) payload includes an Ion Velocity Meter (IVM) to provide measurements of the ion drift motions, density, temperature and major ion composition at the satellite altitude near 575 km. The primary measurement goal for the IVM is to provide the meridional ion drift perpendicular to the magnetic meridian with an accuracy of 7.5 ms-1 for all daytime conditions encountered by the spacecraft within 15° of the magnetic equator. The IVM will derive this parameter utilizing two sensors, a retarding potential analyzer (RPA) and an ion drift meter (IDM) that have a robust and successful flight heritage. The IVM described here incorporates improvements in the design and operation to produce the most sensitive device that has been fielded to date. It will specify the ion drift vector, from which the component perpendicular to the magnetic field will be derived. In addition it will specify the total ion density, the ion temperature and the fractional ion composition. These data will be used in conjunction with measurements from the other ICON instruments to uncover the important connections between the dynamics of the neutral atmosphere and the ionosphere through the generation of dynamo currents perpendicular to the magnetic field and collisional forces parallel to the magnetic field. Here the configuration and operation of the IVM instrument are described as well as the procedures by which the ion drift velocity is determined. A description of the subsystem characteristics, which allow a determination of the expected uncertainties in the derived parameters, is also given.

RESUMEN

The objective of this study was to determine the impact of integrated parasite management (IPM) training, including FAMACHA(©) eyelid color scoring, on the ability of U.S. sheep and goat producers to control gastrointestinal nematodes (GIN) on their farms. A survey was developed and provided to over 2000 producers trained from 2004 to 2008 in IPM with questions involving farm size (number of sheep/goats), location (U.S. state), impact of training on parasite control efforts and parasite problems on farm, and IPM practices used. Responses were divided into U.S. Census regions of the U.S. Descriptive statistics and logistic regression were used to describe results. Most of the 729 respondents were from the southern region of the U.S. (54.3%) and were small-scale producers (50 or less animals; 64.8%). Nearly all of the respondents (95.1%) agreed that IPM workshop attendance made a difference in their ability to control and monitor parasitism in their herd or flock and employed IPM practices to control GIN (96.3%). The most popular practices respondents used were rotational grazing (71.2%), genetic selection (choosing a parasite resistant breed and/or culling susceptible animals; 52.7%), grain supplementation on pasture to improve nutrition (44.0%), and increased height of plants being grazed (41.8%). Although reporting using a practice decreased (P<0.05) the likelihood of reporting fewer problems, for each 1-point increase in the number of practices which producers employed to control internal parasitism in their herd or flock, they were 16% more likely to report fewer GIN problems (P<0.05). Approximately 75% of respondents indicated an economic benefit of IPM on their farm (P<0.05), and those reporting savings of over $80 were more likely to report fewer problems (P<0.05) with parasites after the training while those reporting no economic benefit were less likely to report fewer problems with GIN (P<0.001). Overall, IPM training resulted in positive impacts for producers responding to the survey and should continue.

Asunto(s)

Crianza de Animales Domésticos/educación , Crianza de Animales Domésticos/estadística & datos numéricos , Educación/normas , Enfermedades Gastrointestinales/veterinaria , Enfermedades de las Cabras/prevención & control , Infecciones por Nematodos/veterinaria , Enfermedades de las Ovejas/prevención & control , Animales , Enfermedades Gastrointestinales/parasitología , Enfermedades Gastrointestinales/prevención & control , Enfermedades de las Cabras/parasitología , Cabras , Nematodos/fisiología , Infecciones por Nematodos/prevención & control , Evaluación de Programas y Proyectos de Salud , Ovinos , Enfermedades de las Ovejas/parasitología , Estados Unidos

RESUMEN

Although the highly pathogenic avian influenza H5N1 virus continues to cause infections in both avian and human populations, the specific zoonotic risk factors remain poorly understood. This review summarizes available evidence regarding types of contact associated with transmission of H5N1 virus at the human-animal interface. A systematic search of the published literature revealed five analytical studies and 15 case reports describing avian influenza transmission from animals to humans for further review. Risk factors identified in analytical studies were compared, and World Health Organization-confirmed cases, identified in case reports, were classified according to type of contact reported using a standardized algorithm. Although cases were primarily associated with direct contact with sick/unexpectedly dead birds, some cases reported only indirect contact with birds or contaminated environments or contact with apparently healthy birds. Specific types of contacts or activities leading to exposure could not be determined from data available in the publications reviewed. These results support previous reports that direct contact with sick birds is not the only means of human exposure to avian influenza H5N1 virus. To target public health measures and disease awareness messaging for reducing the risk of zoonotic infection with avian influenza H5N1 virus, the specific types of contacts and activities leading to transmission need to be further understood. The role of environmental virus persistence, shedding of virus by asymptomatic poultry and disease pathophysiology in different avian species relative to human zoonotic risk, as well as specific modes of zoonotic transmission, should be determined.

Asunto(s)

Subtipo H5N1 del Virus de la Influenza A/fisiología , Gripe Aviar/transmisión , Gripe Humana/transmisión , Zoonosis , Animales , Aves , Humanos , Gripe Aviar/virología , Gripe Humana/virología

RESUMEN

OBJECTIVE: Persistent stress and life events affect the course of ulcerative colitis and irritable bowel syndrome by largely unknown mechanisms. Corticotropin-releasing hormone (CRH) has been implicated as an important mediator of stress-induced abnormalities in intestinal mucosal function in animal models, but to date no studies in human colon have been reported. The aim was to examine the effects of CRH on mucosal barrier function in the human colon and to elucidate the mechanisms involved in CRH-induced hyper-permeability. DESIGN: Biopsies from 39 volunteers were assessed for macromolecular permeability (horseradish peroxidase (HRP), (51)Cr-EDTA), and electrophysiology after CRH challenge in Ussing chambers. The biopsies were examined by electron and confocal microscopy for HRP and CRH receptor localisation, respectively. Moreover, CRH receptor mRNA and protein expression were examined in the human mast cell line, HMC-1. RESULTS: Mucosal permeability to HRP was increased by CRH (2.8+/-0.5 pmol/cm(2)/h) compared to vehicle exposure (1.5+/-0.4 pmol/cm(2)/h), p = 0.032, whereas permeability to (51)Cr-EDTA and transmucosal electrical resistance were unchanged. The increased permeability to HRP was abolished by alpha-helical CRH (9-41) (1.3+/-0.6 pmol/cm(2)/h) and the mast cell stabilizer, lodoxamide (1.6+/-0.6 pmol/cm(2)/h). Electron microscopy showed transcellular passage of HRP through colonocytes. CRH receptor subtypes R1 and R2 were detected in the HMC-1 cell line and in lamina propria mast cells in human colon. CONCLUSIONS: Our results suggest that CRH mediates transcellular uptake of HRP in human colonic mucosa via CRH receptor subtypes R1 and R2 on subepithelial mast cells. CRH-induced macromolecular uptake in human colon mucosa may have implications for stress-related intestinal disorders.

Asunto(s)

Colon/ultraestructura , Hormona Liberadora de Corticotropina/fisiología , Mastocitos/metabolismo , Adulto , Anciano , Biopsia , Colon/metabolismo , Femenino , Humanos , Inmunohistoquímica , Masculino , Mastocitos/ultraestructura , Microscopía Electrónica de Transmisión , Persona de Mediana Edad , Permeabilidad , ARN Mensajero/metabolismo , Receptores de Hormona Liberadora de Corticotropina/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa

RESUMEN

The bulk motion of the neutral gas at altitudes between about 200 and 600 km is an important factor in predicting the onset of plasma instabilities that are known to distort and/or disrupt high frequency radio communications. These neutral winds have historically been quite difficult to measure, especially from a moving spacecraft. A new space science instrument called the ram wind sensor has been developed to measure the component of the neutral gas velocity that lies along the orbit track of a satellite in low Earth orbit. Laboratory tests of an engineering model of the instrument have been carried out using a supersonic neutral argon beam, in order to validate the measurement concept. The results show that the technique is viable for measurements of neutral flow velocities in future satellite missions.

RESUMEN

Samples of bulk tank milk from dairies across the United States, taken as part of the National Animal Health Monitoring Dairy 2002 survey, were analyzed for the presence of several genes encoding virulence factors associated with enterohemorrhagic forms of Escherichia coli (EHEC) using real-time and conventional PCR assays. Samples from 859 farms in 21 states were collected and enriched in EC medium at 42.5 degrees C to amplify any E. coli present, and DNA was isolated from the resulting biomass. The eaeA gene encoding intimin, a virulence factor associated with enteropathogenic forms of E. coli and EHEC, was detected in 199 (23%) of the samples. Thirty-six samples (4.2%) were positive for eaeA, the gamma allele of the translocated intimin receptor (gamma-tir), found in EHEC strains of O157:H7, and one or both shiga-like toxin genes (stx1 and stx2), a combination that may be indicative of the presence of O157:H7 EHEC. Testing these 36 samples with a commercially available real-time PCR kit for detection of O157:H7 indicated that 5 samples could be contaminated with O157:H7. A multiplex PCR to detect the presence of fliC, rfbE, and hlyA genes found in O157:H7 reduced to 2 (0.2% of all samples) the number of samples likely to be contaminated with this organism. A strain of O157:H7 (eaeA+, gamma-tir+, stx2+, rfbE+, fliC+, hlyA+) was subsequently isolated from one sample. Thirty-four eaeA-positive samples did not contain detectable gamma-tir but did contain one or both of the stx genes suggesting the presence of EHEC strains other than O157:H7. These results indicate a low incidence of O157:H7 in bulk tank milk but suggest that a risk from other enteropathogenic and EHEC forms of E. coli may exist and that PCR targeting virulence factors associated with highly pathogenic forms of E. coli may be an effective means of detecting potential dangers in raw milk.

Asunto(s)

Escherichia coli O157/aislamiento & purificación , Microbiología de Alimentos , Leche/microbiología , Reacción en Cadena de la Polimerasa/métodos , Factores de Virulencia/análisis , Adhesinas Bacterianas/análisis , Adhesinas Bacterianas/genética , Animales , Cartilla de ADN/química , Escherichia coli O157/genética , Escherichia coli O157/patogenicidad , Proteínas de Escherichia coli/análisis , Proteínas de Escherichia coli/genética , Separación Inmunomagnética , Incidencia , Receptores de Superficie Celular/análisis , Receptores de Superficie Celular/genética , Toxina Shiga I/análisis , Toxina Shiga I/genética , Toxina Shiga II/análisis , Toxina Shiga II/genética , Estados Unidos , Factores de Virulencia/genética

RESUMEN

The intestinal epithelium acts as a barrier restricting uptake of luminal macromolecules such as dietary antigens and microbes. Here, we examined the role of cholinergic signalling in the regulation of permeability to macromolecules. Mouse jejunum was mounted in Ussing chambers and permeability was determined by measuring the flux of the antigen-sized protein, horseradish peroxidase (HRP), across the tissue. Baseline HRP permeability was significantly reduced by neural blockade with tetrodotoxin or cholinergic muscarinic antagonism with atropine, suggesting that ongoing release of endogenous acetylcholine from enteric nerves regulates barrier function. Exogenous addition of the muscarinic agonist bethanechol caused significant increases in both HRP flux and the area of HRP-containing endosomes in enterocytes. Bethanechol-enhanced HRP flux was abrogated by the M3 receptor antagonist, 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP), the phospholipase A(2) inhibitor quinacrine, and the cyclooxygenase inhibitor indomethacin. Complementary in vitro studies showed direct effects of bethanechol on T84 epithelial cells, where increased HRP uptake was associated with increased F-actin, and increased cytosolic phospholipase A(2) (cPLA(2)) phosphorylation. Taken together, these results provide evidence for cholinergic regulation of transepithelial transport of macromolecules, mainly mediated by activation of M3 receptors with subsequent involvement of phospholipase A(2) and cyclooxygenase products.

Asunto(s)

Inserción Epitelial/metabolismo , Agonistas Muscarínicos/farmacología , Receptores Muscarínicos/metabolismo , Actinas/metabolismo , Animales , Transporte Biológico Activo , Western Blotting , Células Cultivadas , Citoesqueleto/efectos de los fármacos , Citoesqueleto/ultraestructura , Citosol/efectos de los fármacos , Citosol/enzimología , Cámaras de Difusión de Cultivos , Endosomas/efectos de los fármacos , Endosomas/ultraestructura , Enterocitos/efectos de los fármacos , Enterocitos/ultraestructura , Inserción Epitelial/efectos de los fármacos , Inserción Epitelial/enzimología , Peroxidasa de Rábano Silvestre , Humanos , Técnicas In Vitro , Indicadores y Reactivos , Masculino , Ratones , Ratones Endogámicos BALB C , Permeabilidad , Fosfolipasas A/metabolismo , Fosforilación , Prostaglandina-Endoperóxido Sintasas/metabolismo , Receptores Muscarínicos/efectos de los fármacos , Transducción de Señal/efectos de los fármacos

RESUMEN

BACKGROUND AND AIMS: Chronic psychological stress, including water avoidance stress (WAS), induces intestinal mucosal barrier dysfunction and impairs mucosal defences against luminal bacteria. The aim of this study was to determine the ability of a defined probiotic regimen to prevent WAS induced intestinal pathophysiology. METHODS: Male rats were subjected to either WAS or sham stress for one hour per day for 10 consecutive days. Additional animals received seven days of Lactobacillus helveticus and L rhamnosus in the drinking water prior to stress and remained on these probiotics for the duration of the study. Rats were then sacrificed, intestinal segments assessed in Ussing chambers, and mesenteric lymph nodes cultured to determine bacterial translocation. RESULTS: All animals remained healthy for the duration of the study. Chronic WAS induced excess ion secretion (elevated baseline short circuit current) and barrier dysfunction (increased conductance) in both the ileum and colon, associated with increased bacterial adhesion and penetration into surface epithelial cells. Approximately 70% of rats subjected to WAS had bacterial translocation to mesenteric lymph nodes while there was no bacterial translocation in controls. Probiotic pretreatment alone had no effect on intestinal barrier function. However, WAS induced increased ileal short circuit current was reduced with probiotics whereas there was no impact on altered conductance. Pretreatment of animals with probiotics also completely abrogated WAS induced bacterial adhesion and prevented translocation of bacteria to mesenteric lymph nodes. CONCLUSION: These findings indicate that probiotics can prevent chronic stress induced intestinal abnormalities and, thereby, exert beneficial effects in the intestinal tract.

Asunto(s)

Traslocación Bacteriana/efectos de los fármacos , Absorción Intestinal/efectos de los fármacos , Probióticos/farmacología , Estrés Psicológico/fisiopatología , Animales , Adhesión Bacteriana/efectos de los fármacos , Enfermedad Crónica , Enterocitos/microbiología , Enterocitos/ultraestructura , Mucosa Intestinal/microbiología , Mucosa Intestinal/ultraestructura , Lactobacillus/fisiología , Ganglios Linfáticos/microbiología , Masculino , Mesenterio , Microscopía Electrónica , Permeabilidad/efectos de los fármacos , Ratas , Ratas Endogámicas BN , Estrés Psicológico/microbiología , Estrés Psicológico/patología

RESUMEN

Sixty-one Listeria monocytogenes strains from raw milk were analyzed with an automated repetitive element-based PCR (rep-PCR) system to examine the utility of this system for serotype grouping and to determine whether specific regional relationships could be identified. Results of the similarity analysis revealed two primary clusters of L. monocytogenes isolates. Cluster 2 exclusively contained serogroup 1/2a isolates; however, two 1/2a isolates were also found in cluster 1. Isolates of serogroups 1/2b, 4b, 3b, and 4c were also in cluster 1. Clusters 1 and 2 were separated at a relative similarity of 86%. Listeria species other than L. monocytogenes (L. ivanovii, L. seeligeri, L. welshimeri, L. grayi, and L. innocua) had similarity scores of less than 80% in pairwise comparisons with the L. monocytogenes isolates. Thus, this method may be useful for species identification once an isolate is characterized as Listeria. When rep-PCR fingerprints of the L. monocytogenes 1/2a isolates were compared, there was no apparent regional grouping. However, discrimination between isolates suggests that the rep-PCR assay might be useful for tracking L. monocytogenes 1/2a and for tracking isolates across regions or within smaller ecological niches. The automated rep-PCR method could not discriminate between serotypes 1/2b and 4b but may be useful for discriminating between 1/2a and other serotypes and for tracking isolates within serotype 1/2a.

Asunto(s)

ADN Bacteriano/análisis , Contaminación de Alimentos/análisis , Listeria monocytogenes/clasificación , Leche/microbiología , Reacción en Cadena de la Polimerasa/métodos , Animales , Automatización , Bovinos , Análisis por Conglomerados , ADN Bacteriano/genética , Microbiología de Alimentos , Humanos , Listeria monocytogenes/aislamiento & purificación , Filogenia , Serotipificación , Especificidad de la Especie

RESUMEN

Samples of bulk tank milk from dairies across the United States, taken as part of the National Animal Health Monitoring System Dairy 2002 survey, were analyzed for the presence of Salmonella enterica using a commercially available real-time polymerase chain reaction (PCR) kit. Samples from 854 farms in 21 states were collected and enriched in tetrathionate broth to amplify any salmonellae present, and DNA was isolated from the resulting biomass. One hundred one samples (11.8%) were shown to contain Salmonella enterica using the real-time PCR assay, whereas conventional culture techniques detected the pathogen in only 22 (2.6%) of the samples. A conventional PCR assay targeting a different gene from Salmonella enterica confirmed the presence of the organism in 94 of the real-time PCR-positive samples. Thus, assay of milk samples by real-time PCR indicates that the prevalence of Salmonella enterica in US bulk tank milk is substantially higher than previously reported.

Asunto(s)

Industria Lechera , Leche/microbiología , Reacción en Cadena de la Polimerasa , Salmonella enterica/genética , Salmonella enterica/aislamiento & purificación , Animales , ADN Bacteriano/análisis , Modelos Logísticos , Estados Unidos

RESUMEN

Pigeon paramyxovirus-1 (PPMV-1) was isolated from pigeons from east-central Alabama and used in association with chicken anemia virus (CAV), infectious bursal disease virus (IBDV), or finch Mycoplasma gallisepticum (MG) in specific-pathogen-free chickens to assess dinical disease and pathology. PPMV-1 infection in all groups was conducted at day 10 of age via the ocular route. The low passage PPMV-1 isolate was inoculated into chickens in different groups at 10 days post-CAV infection, 6 days post-IBDV infection, and 6 days post-finch MG infection, respectively. Additionally, to obtain information on the status of paramyxovirus infection in the wild bird population of the region, we used a multispecies competitive enzyme-linked immunosorbent assay kit to assess serum samples from 180 wild birds representing 24 species obtained throughout 2001. Mild respiratory signs characterized by sneezing were observed in PPMV-1-infected chicks. In the brain, PPMV-1 caused disseminated vasculitis in the neuropile and meninges, sometimes with small foci of gliosis. Most brains had only mild lesions. In the upper respiratory tract, lesions were confined to the larynx and proximal trachea as hyperplasia of laryngeal mucosa-associated lymphoid tissue. In the lung, PPMV-1 caused minimal to moderate multifocal interstitial pneumonia. Lymphocytic expansion occurred in the interstitium of the Harderian gland. PPMV-1 in the spleen caused expansion of the white pulp as a result of hypertrophy of the macrophages in the periarteriolar sheaths accompanied by lymphocytic hyperplasia at the periphery. No severe aggravation of either signs or lesions could be attributed to any of the avian pathogens used in association with PPMV-1. The serologic survey in wild birds showed antibody levels that were considered negative or doubtful. Interestingly, significantly (P < 0.05) higher mean titers were observed during the months of October and November 2001, following closely multiple PPMV-1 episodes of mortality in wild collard doves in northwestern Florida.

Asunto(s)

Avulavirus , Pollos/virología , Passeriformes/virología , Enfermedades de las Aves de Corral/patología , Enfermedades de las Aves de Corral/virología , Virosis/veterinaria , Alabama , Animales , Encéfalo/patología , Encéfalo/virología , Virus de la Anemia del Pollo , Columbidae/virología , Ensayo de Inmunoadsorción Enzimática/veterinaria , Virus de la Enfermedad Infecciosa de la Bolsa , Mycoplasma gallisepticum , Virus de la Enfermedad de Newcastle , Sistema Respiratorio/patología , Sistema Respiratorio/virología , Pruebas Serológicas/veterinaria , Organismos Libres de Patógenos Específicos , Virosis/patología

RESUMEN

Salmonella-spedfic bacteriophages (BP) and competitive exclusion (CE) were used to reduce Salmonella colonization in experimentally infected chickens. A "cocktail" of distinct phage (i.e., phage showing different host ranges and inducing different types of plaques on Salmonella Typhimurium [ST] cultures) was developed. The killing activity of the selected BPs on ST cultures differed significantly, as determined in in vitro killing assays. BPs were administered orally to the chickens several days prior and after ST challenge but not simultaneously. BPs were readily isolated from the feces of the BP-treated chickens approximately 48 hr after administration. A CE product consisting of a defined culture of seven different microbial species was used either alone or in combination with BP treatment. CE was administered orally at hatch. Salmonella counts in intestine, ceca, and a pool of liver/spleen were evaluated in Salmonella-challenged chickens treated with BP or with BP and CE. In both trials 1 and 2, a beneficial effect of the phage treatment on weight gain performance was evident. A reduction in Salmonella counts was detected in cecum and ileum of BP-, CE-, and BP+CE-treated chickens as compared with nontreated birds. In trial 1, BP treatment reduced ST counts to marginal levels in the ileum and reduced counts sixfold in the ceca. A reduction of Salmonella counts with BP, CE, and BP+CE treatments was evident in chickens from trial 2. Both CE and BP treatments showed differences in the reduction of Salmonella counts after challenge between spedmens obtained at days 4 and 14 postchallenge in ceca, liver/spleen, and ileum. The preliminary data presented in this report show that isolation and characterization of Salmonella-specific BP is uncomplicated and feasible on a larger scale. Results indicate a protective effect of both Salmonella-specific BPs and a defined competitive exclusion product against Salmonella colonization of experimentally infected chickens. These results are encouraging for further work on the use of BP as an effective alternative to antibiotics to reduce Salmonella infections in poultry.

Asunto(s)

Pollos , Enfermedades de las Aves de Corral/microbiología , Enfermedades de las Aves de Corral/prevención & control , Salmonelosis Animal/prevención & control , Fagos de Salmonella , Salmonella typhimurium/virología , Animales , Peso Corporal , Intestinos/microbiología , Hígado/microbiología , Probióticos , Especificidad de la Especie , Organismos Libres de Patógenos Específicos , Bazo/microbiología

RESUMEN

BACKGROUND AND AIMS: The exact nature of the epithelial barrier defect in Crohn's disease remains to be elucidated. Previously we showed increased permeability to proteins in ileal Crohn's disease. Our aims were to study if this barrier defect (a) involves endocytotic uptake of antigens and (b) is related to low grade inflammation not detectable by histology. METHODS: Macroscopically normal segments of distal ileum of Crohn's disease patients (n = 10) were subgrouped into non-inflamed (histologically unaffected) and slightly inflamed tissues and studied in Ussing chambers, with normal ileal specimens from colon cancer patients (n = 9) as controls. Endocytotic uptake into enterocytes of the protein antigen horseradish peroxidase was assessed by measuring the area of horseradish peroxidase containing endosomes in electron photomicrographs. Mucosal tumour necrosis factor alpha (TNF-alpha) mRNA was quantified using real time polymerase chain reaction. For comparison, the effects of low doses of TNF-alpha on endosomal uptake of horseradish peroxidase were studied in cultured T84 cells grown on filter supports. RESULTS: The area of horseradish peroxidase containing endosomes was increased (p<0.001) in enterocytes of non-inflamed ileum of Crohn's disease (2.8 (0.7) mum(2)/300 mum(2)) compared with control ileum (0.6 (0.06)). In non-inflamed mucosa, a significant association between endosomal uptake and mucosal expression of TNF-alpha mRNA (p = 0.03) was found. Low concentrations of TNF-alpha (0.25-1.0 ng/ml) enhanced the endosomal uptake of horseradish peroxidase in polarised T84 cells, without affecting transepithelial electrical resistance. CONCLUSIONS: Our findings suggest increased endosomal uptake of antigens in ileal Crohn's disease that may be mediated by TNF-alpha. These data highlight the transcellular route of antigen uptake in barrier dysfunction and implicate the interaction between epithelial cells and the innate immune system in the development of mucosal inflammation.

Asunto(s)

Antígenos/metabolismo , Enfermedad de Crohn/metabolismo , Íleon/metabolismo , Mucosa Intestinal/metabolismo , Factor de Necrosis Tumoral alfa/fisiología , Adulto , Línea Celular , Relación Dosis-Respuesta a Droga , Endosomas/metabolismo , Femenino , Peroxidasa de Rábano Silvestre/farmacocinética , Humanos , Masculino , Persona de Mediana Edad , Permeabilidad , ARN Mensajero/genética , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/farmacología

RESUMEN

Bovine enteroviruses are members of the family Picornaviridae, genus Enterovirus. Whilst little is known about their pathogenic potential, they are apparently endemic in some cattle and cattle environments. Only one of the two current serotypes has been sequenced completely. In this report, the entire genome sequences of bovine enterovirus 2 (BEV-2) strain PS87 and a recent isolate from an endemically infected herd in Maryland, USA (Wye3A) are presented. The recent isolate clearly segregated phylogenetically with sequences representing the BEV-2 serotype, as did other isolates from the endemic herd. The Wye3A isolate shared 82 % nucleotide sequence identity with the PS87 strain and 68 % identity with a BEV-1 strain (VG5-27). Comparison of BEV-2 and BEV-1 deduced protein sequences revealed 72-73 % identity and showed that most differences were single amino acid changes or single deletions, with the exception of the VP1 protein, where both BEV-2 sequences were 7 aa shorter than that of BEV-1. Homology modelling of the capsid proteins of BEV-2 against protein database entries for picornaviruses indicated six significant differences among bovine enteroviruses and other members of the family Picornaviridae. Five of these were on the 'rim' of the proposed enterovirus receptor-binding site or 'canyon' (VP1) and one was near the base of the canyon (VP3). Two of these regions varied enough to distinguish BEV-2 from BEV-1 strains. This is the first report and analysis of full-length sequences for BEV-2. Continued analysis of these wild-type strains should yield useful information for genotyping enteroviruses and modelling enterovirus capsid structure.

Asunto(s)

Enfermedades de los Bovinos/virología , Brotes de Enfermedades , Infecciones por Enterovirus/veterinaria , Enterovirus Bovino/genética , Genoma Viral , Animales , Secuencia de Bases , Proteínas de la Cápside/genética , Bovinos , Enfermedades de los Bovinos/epidemiología , Infecciones por Enterovirus/epidemiología , Enterovirus Bovino/clasificación , Heces/virología , Maryland/epidemiología , Epidemiología Molecular , Datos de Secuencia Molecular , Filogenia , ARN Viral/análisis , Alineación de Secuencia , Moldes Genéticos

RESUMEN

The objective of this study was to determine the prevalence of Salmonella, Listeria monocytogenes, and fecal coliforms in bulk tank milk in the United States. As part of the NAHMS Dairy 2002 survey, 861 bulk tank milk samples were collected from farms in 21 states. Milk was directly plated on selective agars for direct bacterial enumeration and was enriched in selective broths to increase detection sensitivity. Somatic cell counts (SCC) and standard plate counts (SPC) were also determined. Coliforms were detected in 95% (818 of 860) of the samples, and the average SCC was 295,000 cells/mL. Twenty-two samples (2.6%) were culture-positive for Salmonella, and 9 serotypes were identified: Montevideo (n = 7), Newport (n = 4), Muenster (n = 2), Meleagridis (n = 2), Cerro (n = 2), 44:Z36 (Z38) (n = 2), Dublin (n = 1), Anatum (n = 1), and 9, 12:nonmo-tile (n = 1). Listeria monocytogenes was isolated from 56 (6.5%) samples, and serotyping of these isolates yielded 5 serotypes (1/2a, 1/2b, 3b, 4b, and 4c). Of the L. monocytogenes isolates, 93% were serotypes 1/2a, 1/2b, and 4b, the most common human clinical isolates. Regional differences in L. monocytogenes and Salmonella prevalence were observed, but more studies are needed to determine the validity of these differences. There were no apparent relationships between SCC or SPC and incidence of Salmonella or L. monocytogenes. Although the prevalence of L. monocytogenes and Salmonella was low, these pathogens represent a potential risk to consumers of raw milk and raw milk products.

Asunto(s)

Industria Lechera , Enterobacteriaceae/aislamiento & purificación , Heces/microbiología , Listeria monocytogenes/aislamiento & purificación , Leche/microbiología , Salmonella/aislamiento & purificación , Animales , Recuento de Células , Recuento de Colonia Microbiana , Industria Lechera/instrumentación , Industria Lechera/normas , Embalaje de Alimentos , Listeria monocytogenes/clasificación , Leche/citología , Serotipificación

RESUMEN

Central corticotrophin releasing-factor (CRF) signalling pathways are involved in the endocrine, behavioural and visceral responses to stress. Recent studies indicate that peripheral CRF-related mechanisms also contribute to stress-induced changes in gut motility and intestinal mucosal function. Peripheral injection of CRF or urocortin inhibits gastric emptying and motility through interaction with CRF2 receptors and stimulates colonic transit, motility, Fos expression in myenteric neurones and defecation through activation of CRF1 receptors. With regard to intestinal epithelial cell function, intraperitoneal CRF increases ion secretion and mucosal permeability to macromolecules. The motility and mucosal changes induced by peripheral CRF mimic those induced by acute stress. In addition, CRF receptor antagonists given peripherally prevent acute restraint and water avoidance stress-induced delayed gastric emptying, stimulation of colonic motor function and mucosal permeability. Similarly, early trauma enhanced intestinal mucosal dysfunction to an acute stressor in adult rats and the response is prevented by peripheral injection of CRF antagonist. Chronic psychological stress results in reduced host defence and initiates intestinal inflammation through mast cell-dependent mechanisms. These findings provide convergent evidence that activation of peripheral CRF receptors and mast cells are important mechanisms involved in stress-related alterations of gut physiology.

Asunto(s)

Hormona Liberadora de Corticotropina/fisiología , Motilidad Gastrointestinal/fisiología , Transducción de Señal/fisiología , Estrés Fisiológico/fisiopatología , Animales , Humanos , Mucosa Intestinal/fisiología , Receptores de Hormona Liberadora de Corticotropina/fisiología

RESUMEN

A real-time reverse transcriptase/polymerase chain reaction (RRT-PCR) assay was developed using hydrolysis probes for the detection of avian influenza virus (AIV) and the H5 and H7 subtypes. The AIV specific primers and probes were directed to regions of the AIV matrix gene that are conserved among most type A influenza viruses. The H5 and H7 primers and probes are directed to H5 and H7 hemagglutinin gene regions that are conserved among North American avian influenza viruses. The sensitivity and specificity of this RRT-PCR assay was compared to virus isolation (VI) in chicken embryos with 1550 clinical swab samples from 109 live-bird markets (LBMs) in New York and New Jersey. RRT-PCR detected influenza in samples from 61 of 65 (93.8%) of the LBMs that were the sources of VI positive samples. Of the 58 markets that were positive for H7 influenza by hemagglutination inhibition assay, RRT-PCR detected H7 influenza in 56 markets (96.5%). Too few H5 positive samples were obtained to validate the H5 RRT-PCR assay in this study. Although RRT-PCR was less sensitive than VI on an individual sample basis, this study demonstrated that the AIV and H7 RRT-PCR assays are good tools for the rapid screening of flocks and LBMs.

Asunto(s)

Virus de la Influenza A/patogenicidad , Gripe Aviar/diagnóstico , Enfermedades de las Aves de Corral/virología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Animales , Enfermedades de las Aves/diagnóstico , Enfermedades de las Aves/virología , Pollos , Patos , Ensayo de Inmunoadsorción Enzimática/métodos , Virus de la Influenza A/aislamiento & purificación , Enfermedades de las Aves de Corral/diagnóstico , Sensibilidad y Especificidad , Struthioniformes

RESUMEN

The purpose of this study was to determine the efficacy of a portable real-time PCR system in detecting Salmonella spp. in raw milk. The 200 bulk milk samples chosen for this study constituted a subset of the samples for a larger study; this subset contained 24 samples that were culture positive for Salmonella and 176 that were culture negative. Milk was both plated directly on selective agar and plated after enrichment in selective media. Presumptive Salmonella colonies were isolated by direct culturing of five samples, while Salmonella was isolated from the remaining 19 positive samples only after enrichment. Presumptive Salmonella isolates were serotyped, and isolates from 22 samples were confirmed to be Salmonella isolates. PCR assays of culture-positive milk prior to enrichment yielded no evidence of Salmonella. DNA extracts of bacterial pellets from the enriched samples were analyzed for Salmonella by real-time PCR with the Ruggedized Advanced Pathogen Identification Device (RAPID). Fifty-four samples from the enrichment pellets tested positive for Salmonella by real-time PCR. Two samples that tested positive for Salmonella by culture and serotyping tested Salmonella negative by real-time PCR. Serotyping identified isolates from these samples as Salmonella Montevideo. All DNA extracts of Salmonella Montevideo isolates tested positive for Salmonella by real-time PCR. Thirty-three samples tested negative by culture and positive by real-time PCR. These results indicate that the portable real-time PCR system appears to be a useful tool for detecting Salmonella in raw milk. Additionally, the combination of enrichment and real-time PCR techniques used in this study can yield results in 24 h, compared with the 48 to 72 h required for traditional culture.

Asunto(s)

Contaminación de Alimentos/análisis , Leche/microbiología , Reacción en Cadena de la Polimerasa/métodos , Salmonella/aislamiento & purificación , Animales , Bovinos , Medios de Cultivo , ADN Bacteriano/análisis , Microbiología de Alimentos , Humanos , Salmonella/genética , Sensibilidad y Especificidad , Análisis de Secuencia de ADN , Serotipificación

RESUMEN

An influenza pandemic could arise unexpectedly with rapid spread across the world. The efficiency of production of a vaccine and the ability to administer it widely will be among the most important factors in the ability to protect public health. The current process for producing inactivated or live attenuated influenza vaccines requires six to nine months. That reduces considerably the likelihood that the vaccine will be available during the first wave of the pandemic. Therefore, a key element of preparedness is to optimize the production process and to reduce the vaccine development time. During the 1997 H5N1 outbreak in Hong Kong, seed viruses were prepared for production of inactivated and live-attenuated vaccines. We used the cold-adapted A/Ann Arbor/6/60 as the donor virus to generate live attenuated vaccines containing genetically modified HA and NA genes from H5N1 influenza viruses. These reassortants were shown to be safe and protective in animal models. This study indicates that production of live attenuated avian influenza vaccines is feasible and that development of a library of reassortants containing different subtype HA and NA genes may reduce the vaccine preparation time for future influenza pandemics.

Asunto(s)

Antígenos Virales/inmunología , Virus de la Influenza A/inmunología , Gripe Humana/prevención & control , Humanos , Vacunas contra la Influenza/administración & dosificación , Gripe Humana/epidemiología

RESUMEN

BACKGROUND & AIMS: We previously described a system for enhanced transepithelial transport of antigen in which both the amount of specific antigen and its rate of transport were dramatically increased in intestine of sensitized rats compared with controls. This study investigated the essential components mediating antigen uptake in mice genetically deficient for interleukin (IL)-4 or CD23. METHODS: Mice were actively or passively sensitized to horseradish peroxidase (HRP). Jejunal segments from control or sensitized mice were mounted in Ussing chambers and challenged with HRP from the luminal side. Tissues were processed for electron microscopy, and photomicrographs were analyzed for antigen uptake (location and area of HRP-containing endosomes). Immunohistochemistry and reverse-transcription polymerase chain reaction were used to detect epithelial CD23 expression. RESULTS: Actively sensitized IL-4(+/+), but not IL-4(-/-) mice, displayed increased transepithelial antigen transport and CD23 expression on enterocytes. Passively sensitized IL-4(+/+) and IL-4(-/-) mice displayed elevated antigen transport after transfer of immune serum but not if the serum was depleted of immunoglobulin (Ig) E or IL-4. IL-4 added to cultured IEC-4 cells up-regulated expression of CD23 messenger RNA. The augmented antigen uptake was inhibited by anti-CD23 and was absent in sensitized CD23(-/-) mice. CONCLUSIONS: Our studies indicate that IL-4 regulates IgE/CD23-mediated enhanced transepithelial antigen transport in sensitized mouse intestine.

Asunto(s)

Hipersensibilidad a los Alimentos/metabolismo , Inmunoglobulina E/metabolismo , Interleucina-4/metabolismo , Mucosa Intestinal/metabolismo , Receptores de IgE/metabolismo , Animales , Anticuerpos/farmacología , Transporte Biológico/inmunología , Células Cultivadas , Endosomas/metabolismo , Células Epiteliales/citología , Células Epiteliales/inmunología , Células Epiteliales/metabolismo , Hipersensibilidad a los Alimentos/genética , Hipersensibilidad a los Alimentos/inmunología , Expresión Génica/inmunología , Peroxidasa de Rábano Silvestre , Interleucina-4/genética , Mucosa Intestinal/citología , Mucosa Intestinal/inmunología , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Noqueados , ARN Mensajero/análisis , Receptores de IgE/genética , Regulación hacia Arriba/inmunología