Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 30
Filtrar
Más filtros

Banco de datos
Tipo del documento
Intervalo de año de publicación
1.
BMC Infect Dis ; 21(1): 1101, 2021 Oct 26.
Artículo en Inglés | MEDLINE | ID: mdl-34702177

RESUMEN

BACKGROUND: The survival of coronaviruses are influenced by weather conditions and seasonal coronaviruses are more common in winter months. We examine the seasonality of respiratory infections in England and Wales and the associations between weather parameters and seasonal coronavirus cases. METHODS: Respiratory virus disease data for England and Wales between 1989 and 2019 was extracted from the Second-Generation Surveillance System (SGSS) database used for routine surveillance. Seasonal coronaviruses from 2012 to 2019 were compared to daily average weather parameters for the period before the patient's specimen date with a range of lag periods. RESULTS: The seasonal distribution of 985,524 viral infections in England and Wales (1989-2019) showed coronavirus infections had a similar seasonal distribution to influenza A and bocavirus, with a winter peak between weeks 2 to 8. Ninety percent of infections occurred where the daily mean ambient temperatures were below 10 °C; where daily average global radiation exceeded 500 kJ/m2/h; where sunshine was less than 5 h per day; or where relative humidity was above 80%. Coronavirus infections were significantly more common where daily average global radiation was under 300 kJ/m2/h (OR 4.3; CI 3.9-4.6; p < 0.001); where average relative humidity was over 84% (OR 1.9; CI 3.9-4.6; p < 0.001); where average air temperature was below 10 °C (OR 6.7; CI 6.1-7.3; p < 0.001) or where sunshine was below 4 h (OR 2.4; CI 2.2-2.6; p < 0.001) when compared to the distribution of weather values for the same time period. Seasonal coronavirus infections in children under 3 years old were more frequent at the start of an annual epidemic than at the end, suggesting that the size of the susceptible child population may be important in the annual cycle. CONCLUSIONS: The dynamics of seasonal coronaviruses reflect immunological, weather, social and travel drivers of infection. Evidence from studies on different coronaviruses suggest that low temperature and low radiation/sunlight favour survival. This implies a seasonal increase in SARS-CoV-2 may occur in the UK and countries with a similar climate as a result of an increase in the R0 associated with reduced temperatures and solar radiation. Increased measures to reduce transmission will need to be introduced in winter months for COVID-19.


Asunto(s)
COVID-19 , Infecciones del Sistema Respiratorio , Niño , Preescolar , Humanos , Infecciones del Sistema Respiratorio/epidemiología , SARS-CoV-2 , Estaciones del Año , Tiempo (Meteorología)
2.
Br J Cancer ; 111(4): 716-25, 2014 Aug 12.
Artículo en Inglés | MEDLINE | ID: mdl-24921920

RESUMEN

BACKGROUND: A frequent mechanism of acquired multidrug resistance in human cancers is overexpression of ATP-binding cassette transporters such as the Multi-Drug Resistance Protein 1 (MDR-1). Nutlin-3, an MDM2-p53 antagonist, has previously been reported to be a competitive MDR-1 inhibitor. METHODS: This study assessed whether the structurally diverse MDM2-p53 antagonists, MI-63, NDD0005, and RG7388 are also able to modulate MDR-1 function, particularly in p53 mutant neuroblastoma cells, using XTT-based cell viability assays, western blotting, and liquid chromatography-mass spectrometry analysis. RESULTS: Verapamil and the MDM2-p53 antagonists potentiated vincristine-mediated growth inhibition in a concentration-dependent manner when used in combination with high MDR-1-expressing p53 mutant neuroblastoma cell lines at concentrations that did not affect the viability of cells when given alone. Liquid chromatography-mass spectrometry analyses showed that verapamil, Nutlin-3, MI-63 and NDD0005, but not RG7388, led to increased intracellular levels of vincristine in high MDR-1-expressing cell lines. CONCLUSIONS: These results show that in addition to Nutlin-3, other structurally unrelated MDM2-p53 antagonists can also act as MDR-1 inhibitors and reverse MDR-1-mediated multidrug resistance in neuroblastoma cell lines in a p53-independent manner. These findings are important for future clinical trial design with MDM2-p53 antagonists when used in combination with agents that are MDR-1 substrates.


Asunto(s)
Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/metabolismo , Antineoplásicos/farmacología , Resistencia a Antineoplásicos , Neuroblastoma/tratamiento farmacológico , Proteínas Proto-Oncogénicas c-mdm2/antagonistas & inhibidores , Proteína p53 Supresora de Tumor/antagonistas & inhibidores , Subfamilia B de Transportador de Casetes de Unión a ATP , Antineoplásicos/metabolismo , Línea Celular Tumoral , Cisplatino/farmacología , Doxorrubicina/farmacología , Sinergismo Farmacológico , Humanos , Imidazoles/farmacología , Indoles/farmacología , Concentración 50 Inhibidora , Neuroblastoma/metabolismo , Piperazinas/farmacología , Proteínas Proto-Oncogénicas c-mdm2/metabolismo , Pirrolidinas/farmacología , Compuestos de Espiro/farmacología , Proteína p53 Supresora de Tumor/metabolismo , Verapamilo/farmacología , Vincristina/metabolismo , Vincristina/farmacología , para-Aminobenzoatos/farmacología
3.
Epidemiol Infect ; 137(11): 1538-47, 2009 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19371450

RESUMEN

The effects of temperature on reported cases of a number of foodborne illnesses in England and Wales were investigated. We also explored whether the impact of temperature had changed over time. Food poisoning, campylobacteriosis, salmonellosis, Salmonella Typhimurium infections and Salmonella Enteritidis infections were positively associated (P<0.01) with temperature in the current and previous week. Only food poisoning, salmonellosis and S. Typhimurium infections were associated with temperature 2-5 weeks previously (P<0.01). There were significant reductions also in the impact of temperature on foodborne illnesses over time. This applies to temperature in the current and previous week for all illness types (P<0.01) except S. Enteritidis infection (P=0.079). Temperature 2-5 weeks previously diminished in importance for food poisoning and S. Typhimurium infection (P<0.001). The results are consistent with reduced pathogen concentrations in food and improved food hygiene over time. These adaptations to temperature imply that current estimates of how climate change may alter foodborne illness burden are overly pessimistic.


Asunto(s)
Infecciones por Campylobacter/epidemiología , Enfermedades Transmitidas por los Alimentos/epidemiología , Intoxicación Alimentaria por Salmonella/epidemiología , Temperatura , Inglaterra/epidemiología , Efecto Invernadero , Humanos , Modelos Biológicos , Riesgo , Salmonella enteritidis , Salmonella typhimurium , Gales/epidemiología
4.
Bone Marrow Transplant ; 36(6): 491-7, 2005 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-16044139

RESUMEN

In an effort to improve the outcome of poor-risk lymphoma patients, we evaluated a novel regimen of tandem high-dose chemotherapy (THDC) with autologous stem cell transplantation. A total of 41 patients (median age 40 years, range 15-68 years) with poor-risk non-Hodgkin's lymphoma and Hodgkin's disease were enrolled. THDC consisted of melphalan (180 mg/m2) and escalating dose mitoxantrone (30-50 mg/m2) (MMt) for the first conditioning regimen, and thiotepa (500 mg/m2), carboplatin (800 mg/m2), and escalating dose etoposide phosphate (400-850 mg/m2), (ETCb) as the second regimen. In all, 31 patients (76%) completed both transplants, with a median time between transplants of 55 days (range 26-120). The maximum tolerated dose was determined as 40 mg/m2 for mitoxantrone and 550 mg/m2 for etoposide phosphate. The overall toxic death rate was 12%. Following high-dose chemotherapy, 10 of 24 evaluable patients (42%) were in CR. The two-year overall survival and event-free survival is 67% (95% CI, 52-81%) and 45%, (95% CI, 29-61%) for the 41 patients enrolled; and 69% (95% CI, 525-586%) and 48% (95% CI, 30-67%) for the 31 patients completing both transplants. This THDC regimen is feasible but with notable toxicity in heavily pretreated patients; its role in the current treatment of high-risk lymphoma remains to be determined.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Trasplante de Células Madre Hematopoyéticas/métodos , Linfoma/terapia , Adolescente , Adulto , Anciano , Protocolos de Quimioterapia Combinada Antineoplásica/toxicidad , Femenino , Trasplante de Células Madre Hematopoyéticas/mortalidad , Humanos , Linfoma/complicaciones , Linfoma/mortalidad , Masculino , Dosis Máxima Tolerada , Melfalán/administración & dosificación , Persona de Mediana Edad , Mitoxantrona/administración & dosificación , Proyectos Piloto , Riesgo , Análisis de Supervivencia , Acondicionamiento Pretrasplante/métodos , Trasplante Autólogo
5.
J Clin Pathol ; 28(9): 728-30, 1975 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-1100680

RESUMEN

Urines from patients with symptoms of urinary tract infection yielded mixed growths of different colony types of Escherichia coli. The different colony types were found to be variants of single infecting strains caused by mutation or by phase action. It is suggested that care should be exercised in the interpretation of apparently mixed growths from urine.


Asunto(s)
Escherichia coli/aislamiento & purificación , Infecciones Urinarias/microbiología , Bacteriófagos , Femenino , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Mutación , Serotipificación , Orina/microbiología
6.
J Med Microbiol ; 51(11): 1001-1008, 2002 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-12448685

RESUMEN

In 2000, an unusual increase of morbidity and mortality among illegal injecting drug users in the UK and Ireland was reported and Clostridium novyi was identified as the likely source of the serious infection, although infections due to C. botulinum and Bacillus cereus were also reported. Because heroin was a possibile source of infection, this study investigated the microflora of heroin samples seized in England during 2000 and 2002. Two methods were developed for the examination of the microflora of heroin. The first consisted of suspension of the drug in maximum recovery diluent (MRD) which was inoculated directly into Clostridium Botulinum Isolation Cooked Meat Broth (CBI). The second method rendered the heroin soluble in citric acid, concentrated particulate material (and bacterial cells) by filtration and removed heroin residues by washing with citric acid and phosphate-buffered saline before placing the filter in CBI broth. Duplicate CBI broths from both methods were incubated without heating and after heating at 60 degrees C for 30 min. Subcultures were made after incubation for 7 and 14 days on to eight different solid media. The methods were evaluated with heroin samples spiked with either C. botulinum or C. novyi spore suspensions; recovery of 10 spores in the original sample was demonstrated. Fifty-eight heroin samples were tested by citric acid solubilisation and 34 by the MRD suspension technique. Fifteen different gram-positive species of four genera were recognised. No fungi were isolated. Aerobic endospore-forming bacteria (Bacillus spp. and Paenibacillus macerans) were the predominant microflora isolated and at least one species was isolated from each sample. B. cereus was the most common species and was isolated from 95% of all samples, with B. licheniformis isolated from 40%. Between one and five samples yielded cultures of B. coagulans, B. laterosporus, B. pumilus, B. subtilis and P. macerans. Staphylococcus spp. were isolated from 23 (40%) samples; S. warneri and S. epidermidis were the most common and were cultured from 13 (22%) and 6 (10%) samples respectively. One or two samples yielded cultures of S. aureus, S. capitis and S. haemolyticus. The remainder of the flora detected comprised two samples contaminated with C. perfringens and two samples with either C. sordellii or C. tertium. Multiple bacterial species were isolated from 43 (74%) samples, a single species from the remaining 15. In 13 samples B. cereus alone was isolated, in one B. subtilis alone and in one sample B. pumilus alone. C. botulinum and C. novyi were not isolated from any of the heroin samples. Recommendations for the optimal examination of the microflora of heroin are given.


Asunto(s)
Bacillus cereus/aislamiento & purificación , Técnicas de Tipificación Bacteriana/métodos , Clostridium/aislamiento & purificación , Contaminación de Medicamentos , Bacterias Grampositivas/aislamiento & purificación , Heroína/análisis , Medios de Cultivo , Reproducibilidad de los Resultados , Staphylococcus aureus/aislamiento & purificación , Factores de Tiempo
7.
Cancer Genet Cytogenet ; 111(1): 18-20, 1999 May.
Artículo en Inglés | MEDLINE | ID: mdl-10326585

RESUMEN

A patient with BCR/ABL negative myeloproliferative syndrome with a 46,XY,del(3)(q21), t(4;15)(p16;q24) karyotype is described. Fluorescence in situ hybridization performed with chromosomes 4 and 15 painting probes confirmed a novel reciprocal (4;15) translocation. The absence of crkl tyrosine phosphorylation, no activation of the abl kinase as measured by autophosphorylation, and a normal-size abl transcript suggest an alternative mechanism for leukemogenesis to that operative in Ph positive BCR/ABL positive chronic myeloid leukemia. A number of genes potentially relevant to tumorigenesis, some involving the ras signaling pathway, map to the 4p16 and 15q24 chromosome regions.


Asunto(s)
Proteínas de Fusión bcr-abl/genética , Trastornos Mieloproliferativos/genética , Translocación Genética , Reacción de Fase Aguda , Western Blotting , Pintura Cromosómica , Cromosomas Humanos Par 15 , Cromosomas Humanos Par 4 , Progresión de la Enfermedad , Humanos , Masculino , Persona de Mediana Edad , Fosforilación
8.
J Infect ; 42(4): 243-50, 2001 May.
Artículo en Inglés | MEDLINE | ID: mdl-11545566

RESUMEN

OBJECTIVES: To genetically characterize an unusual genotype of Cryptosporidium from the stools of humans with diarrhoea and to identify risk factors in the affected patients. METHODS: DNA was extracted from human faeces where Cryptosporidium oocysts were detected by light microscopy. Cryptosporidial gene fragments from six different loci were analysed by PCR alone, PCR/RFLP and by DNA sequencing. Oocysts were characterized by light and immunofluorescence microscopy and epidemiological data was collected from the affected patients. RESULTS: Analysis of the Cryptosporidium oocyst wall protein (COWP) gene amplified from > 2000 human faecal samples identified 19 patients all of which produced an unusual RFLP profile. Subsequent DNA sequence analysis of this and an additional four genetic loci (including 18S rRNA sequences) confirmed these as a homogeneous group which was genetically distinct from Cryptosporidium parvum. The isolates were identified as Cryptosporidium meleagridis since the gene sequences were identical to those from this species recovered from birds. Conventional microscopy showed oocysts indistinguishable from C. parvum and reacted strongly with two different commercially available anti-oocyst monoclonal antibodies. None of the patients showed risk factors unusual for cryptosporidiosis; however, ten of the cases occurred during the summer/autumn, six had a history of foreign travel, four were co-infected with Giardia, two were HIV positive, and six were without identifiable immunocompromising factors. CONCLUSIONS: This study further confirms that C. meleagridis, in addition to C. parvum, is involved in human disease. The study also highlights the lack of basic information on the host range of this genus of parasites, the complexity of the transmission routes involved in human cryptosporidiosis, and the value of molecular techniques in identify hitherto unrecognised differences in Cryptosporidium from human faeces.


Asunto(s)
Criptosporidiosis/diagnóstico , Cryptosporidium/genética , Heces/parasitología , Adolescente , Adulto , Anciano , Animales , Niño , Preescolar , Criptosporidiosis/parasitología , Cryptosporidium/patogenicidad , Cartilla de ADN , Femenino , Genotipo , Humanos , Masculino , Microscopía Fluorescente , Microscopía de Polarización , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa/métodos , Polimorfismo de Longitud del Fragmento de Restricción , Factores de Riesgo , Análisis de Secuencia de ADN
9.
J Food Prot ; 62(8): 877-82, 1999 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10456740

RESUMEN

The microbiological quality of 4,162 samples of cooked rice from restaurants and take-away premises in the United Kingdom was examined, including ready-to-eat rice purchased at point-of-sale and rice that was stored precooked for reheating on demand. The majority of point-of-sale cooked rice samples (1,855 of 1,972; 94%) were of acceptable microbiological quality, but 15 (1%) samples were of unacceptable quality (Bacillus spp. and B. cereus, > or = 10(5) CFU/g; Escherichia coli, > or = 10(4) CFU/g), indicating a potential risk to health. The prevalence of Bacillus spp., B. cereus, and E. coli was significantly greater in precooked stored rice than in point-of-sale cooked rice (P < 0.005 to 0.0005). Bacillus spp. (> or = 10(4) CFU/g), B. cereus (> or = 10(4) CFU/g), and E. coli (> or = 10(2) CFU/g) were present in 7%, 2%, and 9% of precooked stored samples, respectively, compared to 2%, 0.5%, and 1%, respectively in point-of-sale samples. Although final heating at the point of sale reduces the levels of microorganisms present in rice it will not inactivate the B. cereus emetic toxin if present. Rice from Indian premises was of poorer microbiological quality than that from Chinese and other premises. Although most point-of-sale cooked rice samples (94%) were of an acceptable microbiological quality, evidence from this study indicates that the microbiological quality of cooked rice sold from certain outlets in the UK is of concern.


Asunto(s)
Bacterias/aislamiento & purificación , Manipulación de Alimentos/métodos , Calor , Oryza/microbiología , Restaurantes/normas , Bacillus/aislamiento & purificación , Bacillus cereus/aislamiento & purificación , Bacterias Aerobias/aislamiento & purificación , Recuento de Colonia Microbiana , Escherichia coli/aislamiento & purificación , Manipulación de Alimentos/normas , Microbiología de Alimentos , Oryza/normas , Reino Unido
10.
Acta Cytol ; 41(6): 1839-44, 1997.
Artículo en Inglés | MEDLINE | ID: mdl-9390154

RESUMEN

BACKGROUND: Fine needle aspiration biopsy (FNAB) affords a less expensive, less morbid approach to masses within the complex anatomy of the mediastinum as opposed to surgical biopsy. Given the current state of computed tomography guidance and the available cell block preparations and ancillary studies, definitive diagnosis of mediastinal tumors is possible. CASE: A 19-year-old male presented with weight loss and muscle weakness. Computed tomography revealed an anterior superior mediastinal mass with attachment to the posterior sternum and anterior aorta. FNAB yielded hyperchromatic cells with densely clumped chromatin and prominent nucleoli. These were present as single cells and clusters. Cell block preparations were studied with immunoperoxidase methods and were strongly positive for chromogranin and glucagon, supporting the diagnosis of carcinoid tumor. Surgical excision yielded a 7-cm, unencapsulated, red-brown tumor with medium-sized cells with oval to round nuclei, scant and granular cytoplasm and coarse "salt and pepper" chromatin with prominent nucleoli. The cells were arranged in islands and bands and were associated with prominent capillaries and dense, collagenous septae. Immunoperoxidase and electron microscopy demonstrated numerous intracytoplasmic, nonspecific neurosecretory granules and positivity for somatostatin, synaptophysin, cytokeratin and chromogranin. CONCLUSION: FNAB affords an accurate and timely diagnosis of an anterior mediastinal tumor without the necessity for open biopsy and also offers accurate surgical planning and decreased morbidity.


Asunto(s)
Tumor Carcinoide/patología , Neoplasias del Timo/patología , Adulto , Biomarcadores de Tumor/análisis , Biopsia con Aguja/métodos , Tumor Carcinoide/diagnóstico por imagen , Tumor Carcinoide/cirugía , Tumor Carcinoide/ultraestructura , Nucléolo Celular/patología , Cromatina/patología , Cromograninas/análisis , Gránulos Citoplasmáticos/patología , Gránulos Citoplasmáticos/ultraestructura , Glucagón/análisis , Humanos , Masculino , Neoplasias del Timo/diagnóstico por imagen , Neoplasias del Timo/cirugía , Neoplasias del Timo/ultraestructura , Tomografía Computarizada por Rayos X
13.
Br Med Bull ; 56(1): 209-35, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-10885117

RESUMEN

Pathogenic protozoa are commonly transmitted to food in developing countries, but food-borne outbreaks of infection are relatively rare in developed countries. The main protozoa of concern in developed countries are Toxoplasma, Cryptosporidium and Giardia, and these can be a problem in immunocompromised people. Other protozoa such as Entamoeba histolytica, Cyclospora cayetanensis and Sarcocystis can be a food-borne problem in non-industrialised countries. C. cayetanensis has emerged as a food-borne pathogen in foods imported into North America from South America. Microsporidia may be food-borne, although evidence for this is not yet available. The measures needed to prevent food-borne protozoa causing disease require clear assessments of the risks of contamination and the effectiveness of processes to inactivate them. The globalisation of food production can allow new routes of transmission, and advances in diagnostic detection methods and surveillance systems have extended the range of protozoa that may be linked to food.


Asunto(s)
Parasitología de Alimentos , Infecciones por Protozoos/transmisión , Animales , Apicomplexa , Humanos , Microsporidiosis/transmisión , Microbiología del Agua
14.
Cancer ; 64(7): 1531-3, 1989 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-2550125

RESUMEN

During the period 1970 to 1987, 11 patients with small cell carcinoma of the esophagus were treated at Memorial Sloan-Kettering Cancer Center, New York. This rare tumor was responsible for 1.1% of all patients with esophageal tumors seen on the inpatient services during that period. Using a clinical staging system similar to that employed in small cell cancer of the lung, eight of 11 patients had extensive disease. Although responses were seen to multidrug combination chemotherapy regimens used alone or with sequential radiation, the overall prognosis for small cell esophageal cancer was poor, with a median survival of 7.5 months. Only one patient lived for greater than 2 years.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Carcinoma de Células Pequeñas/tratamiento farmacológico , Neoplasias Esofágicas/tratamiento farmacológico , Anciano , Anciano de 80 o más Años , Carcinoma de Células Pequeñas/radioterapia , Carcinoma de Células Pequeñas/cirugía , Cisplatino/administración & dosificación , Terapia Combinada , Ciclofosfamida/administración & dosificación , Doxorrubicina/administración & dosificación , Evaluación de Medicamentos , Neoplasias Esofágicas/radioterapia , Neoplasias Esofágicas/cirugía , Etopósido/administración & dosificación , Femenino , Humanos , Masculino , Pronóstico , Vincristina/administración & dosificación
15.
J Protozool ; 38(6): 237S-240S, 1991.
Artículo en Inglés | MEDLINE | ID: mdl-1818185

RESUMEN

Antigens extracted from Cryptosporidium oocysts, which had been purified from faeces or chick egg culture, were electrophoresed in sodium dodecyl sulfate-polyacrylamide gels, and blotted onto nitrocellulose membranes. A Cryptosporidium genus-specific monoclonal antibody MAb-C1 bound to multiple bands using several detection techniques, and these corresponded to bands detected using immune rabbit antisera. Using a detection system with fluorescein isothiocyanate (FITC)-labelled MAb-C1 and alkaline phosphatase-labelled anti-FITC, bands were detected between 50 and 300 kDa. Blots were examined directly and by using a laser scanner. The system was shown to be specific for Cryptosporidium spp., giving no staining with a variety of other pathogens, and with negative samples. The oocyst antigen which bound MAb-C1 was stable, and banding patterns were not significantly affected by pretreatment of oocysts with proteinase K, trypsin, formalin, or sodium hypochlorite, methods commonly used during preparation and storage of C. parvum oocysts. However, banding was reduced with potassium dichromate. Of 76 samples containing Cryptosporidium oocysts, 53 showed one or more MAb-C1 staining bands. Cryptosporidium baileyi and C. parvum could be clearly differentiated by their banding patterns, indicating that the system will distinguish between species. Some isolates, including a single isolate of C. muris, produced weak bands which made interpretation difficult. The technique showed differences between isolates of C. parvum, with two different banding types found in human isolates, and other banding types seen in calf and lamb isolates. This method provides a useful way of characterising isolates which may be new species.


Asunto(s)
Cryptosporidium/clasificación , Animales , Anticuerpos Monoclonales , Western Blotting , Bovinos , Pollos , Electroforesis en Gel de Poliacrilamida , Humanos , Serotipificación , Ovinos
16.
J Immunol ; 159(10): 4720-8, 1997 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-9366395

RESUMEN

An important step in the oncogenic transformation of hemopoietic cells and the subsequent development of leukemia is the proliferation of tumor cells in the absence of exogenous growth factors. In most cases of chronic myelocytic leukemia and in some cases of acute myelocytic leukemia and acute lymphocytic leukemia, the bcr-abl oncogene is involved in this process. Although the BCR-Abl oncoprotein demonstrates enhanced tyrosine kinase activity in leukemic cells, the mechanism by which this leads to growth factor independence remains poorly defined. One proposed mechanism is the activation of cytokine signal transduction pathways, possibly by an autocrine loop involving IL-3 and/or granulocyte-macrophage CSF. Examination of several different cell lines expressing BCR-Abl demonstrates that some of these cells have constitutive activation of the JAK/STAT signaling pathway. We have found the constitutive activation of STAT5 in most, but not all, cell lines expressing BCR-Abl. This constitutive activation of STAT5 is variably associated with a corresponding activation of JAK kinases. Ab blocking studies show that the activation of STAT5 in these cell lines cannot be attributed to the activation of an IL-3/granulocyte-macrophage CSF-driven autocrine loop. Interestingly, samples of peripheral blood cells derived from patients with acute myelocytic leukemia and chronic myelocytic leukemia, which express BCR-Abl, demonstrate constitutive activation of STAT family members. These studies suggest that in a variety of leukemic states, BCR-Abl may use a bypass mechanism to activate cytokine signal transduction pathways.


Asunto(s)
Proteínas de Unión al ADN/metabolismo , Proteínas de Fusión bcr-abl/biosíntesis , Leucemia Mielógena Crónica BCR-ABL Positiva/metabolismo , Leucemia Mieloide Aguda/metabolismo , Proteínas de la Leche , Proteínas Tirosina Quinasas/metabolismo , Transactivadores/metabolismo , Animales , Proteínas de Unión al ADN/sangre , Activación Enzimática , Proteínas de Fusión bcr-abl/sangre , Factor Estimulante de Colonias de Granulocitos y Macrófagos/antagonistas & inhibidores , Factor Estimulante de Colonias de Granulocitos y Macrófagos/metabolismo , Humanos , Interferón gamma/sangre , Interleucina-3/antagonistas & inhibidores , Interleucina-3/metabolismo , Leucemia Mielógena Crónica BCR-ABL Positiva/sangre , Leucemia Mielógena Crónica BCR-ABL Positiva/enzimología , Leucemia Mieloide Aguda/enzimología , Ratones , Proteínas Tirosina Quinasas/sangre , Factor de Transcripción STAT1 , Factor de Transcripción STAT5 , Transducción de Señal , Transactivadores/sangre , Células Tumorales Cultivadas
17.
Emerg Infect Dis ; 7(1): 49-56, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11266294

RESUMEN

We developed a sensitive nested polymerase chain reaction procedure for the Cryptosporidium oocyst wall protein (COWP) gene. Amplification and genotyping were successful in 95.2% of 1,680 fecal samples, 77.6% by the unnested and 17.6% by the nested COWP procedure. The COWP gene was amplified from 2,128 fecal samples: 71 from livestock animals and 2,057 from humans. This series included 706 cases from seven drinking water-associated outbreaks and 51 cases from five swimming pool-associated outbreaks, as well as 1,300 sporadic cases.


Asunto(s)
Reacción en Cadena de la Polimerasa , Proteínas Protozoarias/genética , Animales , Cryptosporidium/crecimiento & desarrollo , Genotipo , ARN Ribosómico 18S/genética , Agua/parasitología , Abastecimiento de Agua
18.
Epidemiol Infect ; 130(3): 469-79, 2003 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12825731

RESUMEN

In England and Wales over the last 30 years there have been 25 reported outbreaks of infection, associated with private water supplies (PWS). The majority (16 outbreaks) were reported after the introduction of enhanced surveillance. Although PWS only serve 0.5% of the population, 36% of drinking water outbreaks are associated with PWS. The main pathogen, campylobacter, was implicated in 13 (52%) outbreaks. Most reported outbreaks (88%) occurred in commercial or Category Two supplies, which potentially affect larger populations. The main factors implicated in these outbreaks are temporary or transient populations, treatment (lack or failure), the presence of animals and heavy rains. The public health problem associated with PWS could be prevented by the identification and understanding of risk factors, by the proper protection of water sources and adequate treatment and maintenance. This could be facilitated through the introduction of a risk assessment as part of a scheme for PWS.


Asunto(s)
Enfermedades Transmisibles/epidemiología , Brotes de Enfermedades , Microbiología del Agua , Abastecimiento de Agua , Control de Enfermedades Transmisibles , Enfermedades Transmisibles/microbiología , Brotes de Enfermedades/prevención & control , Inglaterra/epidemiología , Humanos , Factores de Riesgo , Gales/epidemiología
19.
J Clin Microbiol ; 38(11): 3984-90, 2000 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11060056

RESUMEN

Cryptosporidium present in 1,705 fecal samples from humans and 105 from livestock animals were analyzed by PCR-restriction fragment length polymorphism of the Cryptosporidium oocyst wall protein. Overall, genotype 1 (human exclusive type) was detected in 37.8% of the samples from humans, genotype 2 (broad host range) was detected in 61.5%, a third genotype designated genotype 3 (Cryptosporidium meleagridis) was detected in 0.3%, and both genotypes 1 and 2 were recovered from 0.4%. All samples from livestock yielded genotype 2. Among 469 patients infected during eight drinking water-related outbreaks, five outbreaks were predominantly due to genotype 1, and three were due to genotype 2. Fifty-four samples were collected from patients involved with five swimming pool-associated outbreaks: two outbreaks were due to genotype 1, one was due to genotype 2, and the remaining two involved both genotypes 1 and 2. Among 26 family outbreaks and 1 children's nursery outbreak (2 to 3 members per group), the same genotype was recovered from the different members of each outbreak: 13 were due to genotype 1, and 14 were due to genotype 2. In eighteen patients reporting contact with animals and/or farms, genotype 1 was recovered from one patient and genotype 2 was recovered from the remaining 17. Among the sporadic cases, there were distinct geographical and temporal variations in the distribution of the genotypes. The spring peak in cases was due to genotype 2. Genotype 1 was significantly more common in patients infected during the late-summer-autumn peak and in those with a history of foreign travel.


Asunto(s)
Criptosporidiosis/epidemiología , Cryptosporidium/clasificación , Cryptosporidium/genética , Heces/parasitología , Animales , Animales Domésticos/parasitología , Criptosporidiosis/parasitología , Cryptosporidium/aislamiento & purificación , Genes Protozoarios , Genotipo , Humanos , Epidemiología Molecular , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción , Reino Unido/epidemiología
20.
Epidemiol Infect ; 124(3): 417-25, 2000 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-10982065

RESUMEN

Results from statutory testing of private water supplies in nine Public Health Laboratories in England were compiled, and the effects of supply class, source, treatment and location on water quality were examined. A total of 6551 samples from 2911 supplies was examined, over a 2-year period, of which 1342 (21%) samples, and 949 (33%) supplies on at least one occasion, failed current regulations for Escherichia coli. Total coliforms, including E. coli, were detected in 1751 (27%) samples from 1215 (42%) supplies. The percentage of samples positive for E. coli was highest in summer and autumn, and lowest in winter. Samples taken from larger supplies and from boreholes were less frequently contaminated than those from other sources. Chlorination, filtration or UV light treatment improved the bacteriological quality of supplies, but still resulted in a low level of compliance with the regulations. The public health implications of the study are discussed.


Asunto(s)
Escherichia coli/aislamiento & purificación , Abastecimiento de Agua , Cloro , Recolección de Datos , Inglaterra/epidemiología , Infecciones por Escherichia coli/prevención & control , Filtración , Humanos , Salud Pública , Política Pública , Estaciones del Año , Microbiología del Agua
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA