RESUMEN
Oil sand operations in Alberta, Canada will eventually include returning treated process-affected waters to the environment. Organic constituents in oil sand process-affected water (OSPW) represent complex mixtures of nonionic and ionic (e.g., naphthenic acids) compounds, and compositions can vary spatially and temporally, which has impeded development of water quality benchmarks. To address this challenge, it was hypothesized that solid phase microextraction fibers coated with polydimethylsiloxane (PDMS) could be used as a biomimetic extraction (BE) to measure bioavailable organics in OSPW. Organic constituents of OSPW were assumed to contribute additively to toxicity, and partitioning to PDMS was assumed to be predictive of accumulation in target lipids, which were the presumed site of action. This method was tested using toxicity data for individual model compounds, defined mixtures, and organic mixtures extracted from OSPW. Toxicity was correlated with BE data, which supports the use of this method in hazard assessments of acute lethality to aquatic organisms. A species sensitivity distribution (SSD), based on target lipid model and BE values, was similar to SSDs based on residues in tissues for both nonionic and ionic organics. BE was shown to be an analytical tool that accounts for bioaccumulation of organic compound mixtures from which toxicity can be predicted, with the potential to aid in the development of water quality guidelines.
Asunto(s)
Yacimiento de Petróleo y Gas , Contaminantes Químicos del Agua , Alberta , Ácidos Carboxílicos , Lípidos , Compuestos OrgánicosRESUMEN
The fermentation of three arabinoxylan (AX) fractions from wheat by the human fecal microflora was investigated in vitro. Three AX fractions, with average molecular masses of 354, 278, and 66 kDa, were incorporated into miniature-scale batch cultures (with inulin as a positive prebiotic control) with feces from three healthy donors, aged 23-29. Microflora changes were monitored by the culture-independent technique, fluorescent in situ hybridization, and short chain fatty acid (SCFA) and lactic acid production were measured by high-performance liquid chromatography. Total cell numbers increased significantly in all treated cultures, and the fermentation of AX was associated with a proliferation of the bifidobacteria, lactobacilli, and eubacteria groups. Smaller but statistically significant increases in bacteroides and clostridia groups were also observed. All AX fractions had comparable bifidogenic impacts on the microflora at 5 and 12 h, but the 66 kDa AX was particularly selective for lactobacilli. Eubacteria increased significantly on all AX fractions, particularly on 66 kDa AX. As previously reported, inulin gave a selective increase in bifidobacteria. All supplemented cultures showed significant rises in total SCFA production, with a particularly high proportion of butyric acid being produced from AX fermentation. The prebiotic effect, that is, the selectivity of AX for bifidobacteria and lactobacilli groups, increased as the molecular mass of the AX decreased. This suggests that molecular mass may influence the fermentation of AX in the colon.
Asunto(s)
Colon/metabolismo , Heces/microbiología , Triticum/metabolismo , Xilanos/metabolismo , Adulto , Colon/microbiología , Ácidos Grasos Volátiles/análisis , Femenino , Fermentación , Humanos , Hibridación Fluorescente in Situ , Ácido Láctico/análisis , MasculinoRESUMEN
Temozolomide is an alkylating agent with activity in the treatment of melanoma metastatic to the brain. Lomustine is a nitrosurea that crosses the blood brain barrier and there is evidence to suggest that temozolomide may reverse resistance to lomustine. A multicentre phase I/II study was conducted to assess the maximum-tolerated dose (MTD), safety and efficacy of the combination of temozolomide and lomustine in melanoma metastatic to the brain. Increasing doses of temozolomide and lomustine were administered in phase I of the study to determine the MTD. Patients were treated at the MTD in phase II of the study to six cycles, disease progression or unacceptable toxicity. Twenty-six patients were enrolled in the study. In phase I of the study, the MTD was defined as temozolomide 150 mg m(-2) days 1-5 every 28 days and lomustine 60 mg m(-2) on day 5 every 56 days. Dose-limiting neutropaenia and thrombocytopaenia were observed at higher doses. Twenty patients were treated at this dose in phase II of the study. No responses to therapy were observed. Median survival from starting chemotherapy was 2 months. The combination of temozolomide and lomustine in patients with brain metastases from melanoma does not demonstrate activity. The further evaluation of this combination therefore is not warranted.
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias Encefálicas/tratamiento farmacológico , Dacarbazina/análogos & derivados , Lomustina/administración & dosificación , Melanoma/tratamiento farmacológico , Administración Oral , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Neoplasias Encefálicas/secundario , Dacarbazina/administración & dosificación , Dacarbazina/efectos adversos , Relación Dosis-Respuesta a Droga , Esquema de Medicación , Femenino , Estudios de Seguimiento , Humanos , Lomustina/efectos adversos , Masculino , Dosis Máxima Tolerada , Melanoma/secundario , Persona de Mediana Edad , Neutropenia/inducido químicamente , Temozolomida , Trombocitopenia/inducido químicamente , Insuficiencia del TratamientoRESUMEN
Menopausal estrogen replacement therapy is thought to be responsible for the recent decline in colorectal cancer (CRC) incidence among women. In the C57BL/6J-Min/+ mouse, an animal model of CRC, 17beta-estradiol (E(2)) prevents tumor formation in ovariectomized females. We examined human CRC intestinal cell lines to determine whether particular E(2) metabolites produced anti-tumor effects. Treatment of CRC cells with 2-methoxyestradiol (2-MeOE(2)) increased expression of p53 and p21(WAF1/CIP1) proteins and induced apoptosis, but did not produce changes in expression of estrogen receptor (ER)alpha or ERbeta. The finding that 2-MeOE(2) induces p53-mediated colon cell apoptosis in vitro supports a role for 2-MeOE(2) as an endogenous mediator of intestinal tumor suppression.
Asunto(s)
Apoptosis/efectos de los fármacos , Neoplasias Colorrectales/patología , Estradiol/análogos & derivados , Estradiol/farmacología , Células Tumorales Cultivadas/efectos de los fármacos , Proteína p53 Supresora de Tumor/metabolismo , 2-Metoxiestradiol , Western Blotting , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/metabolismo , Inhibidor p21 de las Quinasas Dependientes de la Ciclina , Ciclinas/metabolismo , Receptor alfa de Estrógeno , Receptor beta de Estrógeno , Humanos , Poli(ADP-Ribosa) Polimerasas/metabolismo , Receptores de Estrógenos/metabolismo , Células Tumorales Cultivadas/metabolismoRESUMEN
OBJECTIVE: To measure quality of life (QoL), using validated health status instruments, of patients with functioning IPAA for CUC. PATIENTS AND METHODS: Between 1986 and 1997, a total of 77 patients had an IPAA. Thirteen patients were excluded [6 excised, 3 awaiting ileostomy closure, 2 lost to follow up, 2 serious unrelated illnesses]. Postal survey using SF36 and EuroQol questionnaires. Age, sex, year of pouch construction and stool frequency were documented. RESULTS: Fifty-six patients (87.5%) replied. Male:female ratio; 3:2. Median age; 34 years (range 13-64). Median time since pouch construction; 4 years (range 1-10 years). Median SF36 scores (range); physical function 86.6 (0-100), physical role 81.6 (0-100), body pain 78.4 (22-100), general health 61.6 (5-100), vitality 57.6 (5-100), social function 75.4 (25-100), emotional role 83.5 (0-100), mental health 70.7 (16-100). All the SF36 scores were within the normal range, as were the EuroQol scores. Median EuroQol score (range); 0.85 (-0.07-1.0). Median EuroQol thermometer score (range); 83.3 (20-100). There was no correlation between objective QoL score and age, gender, stool frequency and year of pouch construction. CONCLUSION: The QoL for patients with a functioning IPAA for CUC measured using validated health status instruments is normal. Age, gender, stool frequency and year of construction do not affect QoL outcome after the IPAA for ulcerative colitis.
RESUMEN
GABA(B) receptors are G-protein-coupled receptors that mediate the slow and prolonged synaptic actions of GABA in the CNS via the modulation of ion channels. Unusually, GABA(B) receptors form functional heterodimers composed of GABA(B1) and GABA(B2) subunits. The GABA(B1) subunit is essential for ligand binding, whereas the GABA(B2) subunit is essential for functional expression of the receptor dimer at the cell surface. We have used real-time reverse transcriptase-polymerase chain reaction to analyse expression levels of these subunits, and their associated splice variants, in the CNS and peripheral tissues of human and rat. GABA(B1) subunit splice variants were expressed throughout the CNS and peripheral tissues, whereas surprisingly GABA(B2) subunit splice variants were neural specific. Using novel antisera specific to individual GABA(B) receptor subunits, we have confirmed these findings at the protein level. Analysis by immunoblotting demonstrated the presence of the GABA(B1) subunit, but not the GABA(B2) subunit, in uterus and spleen. Furthermore, we have shown the first immunocytochemical analysis of the GABA(B2) subunit in the brain and spinal cord using a GABA(B2)-specific antibody. We have, therefore, identified areas of non-overlap between GABA(B1) and GABA(B2) subunit expression in tissues known to contain functional GABA(B) receptors. Such areas are of interest as they may well contain novel GABA(B) receptor subunit isoforms, expression of which would enable the GABA(B1) subunit to reach the cell surface and form functional GABA(B) receptors.
Asunto(s)
Sistema Nervioso Central/metabolismo , Receptores de GABA-B/metabolismo , Animales , Encéfalo/metabolismo , Femenino , Humanos , Masculino , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-Dawley , Receptores de GABA-B/genética , Médula Espinal/metabolismo , Bazo/metabolismo , Distribución Tisular , Útero/metabolismoRESUMEN
The vanilloid receptor-1 (VR1) is a ligand-gated, non-selective cation channel expressed predominantly by sensory neurons. VR1 responds to noxious stimuli including capsaicin, the pungent component of chilli peppers, heat and extracellular acidification, and it is able to integrate simultaneous exposure to these stimuli. These findings and research linking capsaicin with nociceptive behaviours (that is, responses to painful stimuli in animals have led to VR1 being considered as important for pain sensation. Here we have disrupted the mouse VR1 gene using standard gene targeting techniques. Small diameter dorsal root ganglion neurons isolated from VR1-null mice lacked many of the capsaicin-, acid- and heat-gated responses that have been previously well characterized in small diameter dorsal root ganglion neurons from various species. Furthermore, although the VR1-null mice appeared normal in a wide range of behavioural tests, including responses to acute noxious thermal stimuli, their ability to develop carrageenan-induced thermal hyperalgesia was completely absent. We conclude that VR1 is required for inflammatory sensitization to noxious thermal stimuli but also that alternative mechanisms are sufficient for normal sensation of noxious heat.
Asunto(s)
Hiperalgesia/etiología , Neuronas Aferentes/fisiología , Receptores de Droga/fisiología , Adenosina Trifosfato/metabolismo , Animales , Ácidos Araquidónicos/farmacología , Conducta Animal , Capsaicina/farmacología , Carragenina , Células Cultivadas , Electrofisiología , Endocannabinoides , Femenino , Ganglios Espinales/citología , Ganglios Espinales/fisiología , Marcación de Gen , Calor , Concentración de Iones de Hidrógeno , Inflamación/inducido químicamente , Inflamación/etiología , Masculino , Ratones , Ratones Endogámicos C57BL , Dolor , Alcamidas Poliinsaturadas , Receptores de Droga/genética , Células Madre , Canales Catiónicos TRPV , Ácido gamma-Aminobutírico/metabolismoRESUMEN
U-73122, an N-aminosteroid homologue of N-ethylmaleimide (NEM), widely used as an inhibitor of phospholipase C, was found to be a potent inhibitor (IC50 5.5+/-0.5 microM) of the binding of [3H]mepyramine to guinea-pig cerebellar membranes. The succinimido analogue, U-73343, also inhibited the binding of [3H]mepyramine (estimated IC50 24+/-1 microM), but NEM was only a weak inhibitor, even at 10 mM. The interaction of U-73122 and U-73343 with the H1 receptor was effectively irreversible, on the time-scale of the experiment. There is no indication that reaction with a receptor thiol residue is involved in the binding of U-73122, since preincubation of membranes with 2 mM NEM did not significantly increase the IC50 for the inhibition of [3H]mepyramine binding by U-73122. We conclude that U-73122 binds to the histamine H1 receptor in the concentration range in which it acts as an inhibitor or PLC. This compromises the use of U-73122 to provide evidence that an H1 agonist action is mediated via PLC. The tight binding of U-73343 to the receptor appears to be primarily a function of the hydrophobic nature of the compound.
Asunto(s)
Estrenos/metabolismo , Pirrolidinonas/metabolismo , Receptores Histamínicos H1/metabolismo , Animales , Unión Competitiva , Estrenos/farmacología , Etilmaleimida/metabolismo , Etilmaleimida/farmacología , Cobayas , Concentración 50 Inhibidora , Cinética , Masculino , Inhibidores de Fosfodiesterasa/metabolismo , Inhibidores de Fosfodiesterasa/farmacología , Pirilamina/antagonistas & inhibidores , Pirilamina/metabolismo , Pirrolidinonas/farmacología , Tritio , Fosfolipasas de Tipo C/antagonistas & inhibidoresRESUMEN
The 21.7-kb replicase locus of mouse hepatitis virus strain A59 (MHV-A59) encodes several putative functional domains, including three proteinase domains. Encoded closest to the 5' terminus of this locus is the first papain-like proteinase (PLP-1) (S. C. Baker et al., J. Virol. 67:6056-6063, 1993; H.-J. Lee et al., Virology 180:567-582, 1991). This cysteine proteinase is responsible for the in vitro cleavage of p28, a polypeptide that is also present in MHV-A59-infected cells. Cleavage at a second site was recently reported for this proteinase (P. J. Bonilla et al., Virology 209:489-497, 1995). This new cleavage site maps to the same region as the predicted site of the C terminus of p65, a viral polypeptide detected in infected cells. In this study, microsequencing analysis of the radiolabeled downstream cleavage product and deletion mutagenesis analysis were used to identify the scissile bond of the second cleavage site to between Ala832 and Gly833. The effects of mutations between the P5 and P2' positions on the processing at the second cleavage site were analyzed. Most substitutions at the P4, P3, P2, and P2' positions were permissive for cleavage. With the exceptions of a conservative P1 mutation, Ala832Gly, and a conservative P5 mutation, Arg828Lys, substitutions at the P5, P1, and P1' positions severely diminished second-site proteolysis. Mutants in which the p28 cleavage site (Gly247 / Val248) was replaced by the Ala832 / Gly833 cleavage site and vice versa were found to retain processing activity. Contrary to previous reports, we determined that the PLP-1 has the ability to process in trans at either the p28 site or both cleavage sites, depending on the choice of substrate. The results from this study suggest a greater role by the PLP-1 in the processing of the replicase locus in vivo.
Asunto(s)
ADN Viral/genética , Endopeptidasas/genética , Genes Virales , Virus de la Hepatitis Murina/genética , Secuencia de Aminoácidos , Animales , Eliminación de Gen , Ratones , Datos de Secuencia Molecular , Virus de la Hepatitis Murina/enzimología , Transcripción GenéticaRESUMEN
OBJECTIVE: Our purpose was to prove our hypothesis that once preterm uterine contractions and/or labor is controlled with intravenous tocolysis, oral terbutaline, as a maintenance drug, does not prolong pregnancy. STUDY DESIGN: Before discharge, 184 patients between 24 and 35 completed weeks' gestation were prospectively randomized to continued bed rest either with or without oral terbutaline. Assignment was made with stratification into four groups: group 1, those patients with a Bishop score > or = 5 with oral terbutaline (n = 50); group 2, those with a Bishop score > or = 5 without oral terbutaline (n = 53); group 3, those with a Bishop score < 5 with oral terbutaline (n = 41); group 4, those with a Bishop score < 5 without oral terbutaline (n = 40). Oral terbutaline was discontinued at 37 completed weeks. RESULTS: No statistically significant differences were found in the number of readmissions, the number of unscheduled hospital visits, and the neonatal outcomes among the four groups. The gestational age at delivery and percent of deliveries at > or = 37 weeks were not significantly different when group 1 was compared with group 2 and group 3 was compared with group 4. CONCLUSION: Oral terbutaline maintenance does not improve pregnancy outcome in patients who have had initial successful intravenous tocolysis.
Asunto(s)
Trabajo de Parto Prematuro/prevención & control , Pacientes Ambulatorios , Terbutalina/uso terapéutico , Administración Oral , Adulto , Reposo en Cama , Peso al Nacer , Cesárea , Parto Obstétrico , Femenino , Edad Gestacional , Humanos , Recién Nacido , Enfermedades del Recién Nacido/epidemiología , Tiempo de Internación , Morbilidad , Embarazo , Terbutalina/administración & dosificaciónRESUMEN
Sequence analysis of the mouse hepatitis virus, strain A59 (MHV-A59) genome predicts the presence of two papain-like proteinases encoded within the first open reading frame (ORF 1a) of the replicase gene. The more 5' of these domains, the leader papain-like proteinase, is responsible for the cleavage of the amino terminal protein, p28. The core of this proteinase domain was defined to between amino acids 1084 and 1316 from the beginning of ORF 1a. Through the use of deletion analysis coupled with in vitro expression, we studied the role of the coding region between p28 and the leader papain-like proteinase on the cleavage of p28 itself. Expression of a series of deletion mutants showed processing of p28, albeit at lower levels. Reduced p28 production resulting from a 0.4-kb deletion positioned between p28 and the proteinase domain suggests an involvement of this region in catalytic processing. Some mutants displayed cleavage patterns indicative of a second cleavage site. Interestingly, this new cleavage site identified in vitro maps to a position similar to the expected cleavage site of a p65 polypeptide detected in MHV-A59-infected cells. Mutagenesis of the catalytic His1272 residue demonstrates that both cleavages observed are mediated by the leader papain-like proteinase encoded in ORF 1a.
Asunto(s)
Virus de la Hepatitis Murina/enzimología , Papaína/biosíntesis , Papaína/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Sitios de Unión , Proteasas Similares a la Papaína de Coronavirus , Cartilla de ADN , Electroforesis en Gel de Poliacrilamida , Epítopos/análisis , Genoma Viral , Histidina , Ratones , Datos de Secuencia Molecular , Virus de la Hepatitis Murina/genética , Mutagénesis Sitio-Dirigida , Sistemas de Lectura Abierta , Papaína/aislamiento & purificación , Plásmidos , Reacción en Cadena de la Polimerasa , Sistemas de Lectura , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/aislamiento & purificación , Mapeo Restrictivo , Eliminación de SecuenciaRESUMEN
Mouse hepatitis virus strain A59 encodes a papain-like cysteine proteinase (PLP-1) that, during translation of ORF1a, cleaves p28 from the amino terminus of the growing polypeptide chain. In order to determine the amino acid sequences surrounding the p28 cleavage site, the first 4.6 kb of murine hepatitis virus strain A59 ORF1a was expressed in a cell-free transcription-translation system. Amino-terminal radiosequencing of the resulting downstream cleavage product demonstrated that cleavage occurs between Gly-247 and Val-248. Site-directed mutagenesis of amino acids surrounding the p28 cleavage site revealed that substitutions of Arg-246 (P2) and Gly-247 (P1) nearly eliminated cleavage of p28. Single-amino-acid substitutions of other residues between P7 and P2' were generally permissive for cleavage, although a few changes did greatly reduce proteolysis. The relationship between the p28 cleavage site and other viral and cellular papain proteinase cleavage sites is discussed.
Asunto(s)
Virus de la Hepatitis Murina/química , Papaína/fisiología , Proteínas Virales/metabolismo , Secuencia de Aminoácidos , Animales , Ratones , Datos de Secuencia Molecular , Alineación de Secuencia , Relación Estructura-Actividad , Proteínas Virales/químicaRESUMEN
A 65-kDa protein has been detected in mouse hepatitis virus A59 (MHV-A59)-infected DBT cells using polyclonal antibodies directed against polypeptides encoded by the 5' 1.8 kb of gene 1. The presence of this 65-kDa protein (p65) was previously predicted from immunoprecipitation studies of gene 1 expression in MHV-A59-infected DBT cells with other antisera (1). p65 was rapidly labeled in virus-infected cells at late times of infection; however, its cleavage from the polyprotein was significantly delayed compared to the amino-terminal gene 1 polyprotein cleavage product, p28. Similar to p28, p65 was cleaved from the growing polyprotein without detectable intermediate precursors. Kinetic analysis of p65 with specific antibodies indicates that p65 is immediately adjacent to p28 in the gene 1 polyprotein. The proteolytic activity responsible for the carboxy-terminal cleavage of p65, as well as the function of the p65 protein, remains to be determined.
Asunto(s)
Genes Virales/genética , Virus de la Hepatitis Murina/genética , Procesamiento Proteico-Postraduccional , Proteínas Virales/metabolismo , Animales , Células Cultivadas , Cinética , Ratones , Peso Molecular , Sistemas de Lectura Abierta/genética , Pruebas de Precipitina , Biosíntesis de Proteínas , Proteínas Recombinantes de Fusión/biosíntesis , Proteínas Virales/químicaRESUMEN
During translation of Murine hepatitis virus (MHV-A59) ORF1a, p28, the N-terminal polypeptide is cleaved from the growing polypeptide chain. Amino terminal radiosequencing of the resulting downstream cleavage product demonstrated that cleavage occurs between Gly247 and Val248. Site directed mutagenesis of amino acids surrounding the p28 cleavage site revealed that substitutions of Arg246 (P2) and Gly247 (P1) nearly eliminated cleavage of p28. Single amino acid substitutions of other residues between P7 and P2' were generally permissive for cleavage although a few changes did greatly reduce proteolysis. The amino acids around the p28 cleavage site represent a new sequence recognized by a virus encoded papain-like proteinase.
Asunto(s)
Virus de la Hepatitis Murina/metabolismo , Proteínas Virales/metabolismo , Secuencia de Aminoácidos , Animales , Arginina , Sitios de Unión , Glicina , Ratones , Datos de Secuencia Molecular , Virus de la Hepatitis Murina/genética , Mutagénesis Sitio-Dirigida , Sistemas de Lectura Abierta , Mutación Puntual , Reacción en Cadena de la Polimerasa , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Mapeo Restrictivo , Proteínas Virales/biosíntesis , Proteínas Virales/químicaRESUMEN
Rupture of the left ventricle during the immediate postoperative period is a serious, but uncommon complication of mitral valve replacement. This review article outlines the pathological findings, possible causative mechanisms and current management of this cardiac surgical catastrophe.
Asunto(s)
Rotura Cardíaca/etiología , Prótesis Valvulares Cardíacas/efectos adversos , Ventrículos Cardíacos , Válvula Mitral/cirugía , Complicaciones Posoperatorias , Anciano , Femenino , Humanos , Incidencia , Masculino , Complicaciones Posoperatorias/epidemiologíaRESUMEN
MHV gene 1 contains two ORFs in different reading frames. Translation proceeds through ORF 1a into ORF 1b via a translational frame-shift. ORF 1a potentially encodes three protease activities, two papain-like activities and one poliovirus 3C-like activity. Of the three predicted activities, only the more amino terminal papain-like domain has been demonstrated to have protease activity. ORF 1a polypeptides have been detected in infected cells by the use of antibodies. The order of polypeptides encoded from the 5' end of the ORF is p28, p65, p290. p290 is processed into p240 and p50. Processing of ORF1a polypeptides differs during cell free translation of genome RNA and in infected cells, suggesting that different proteases may be active under different conditions. Two RNA negative mutants of MHV-A59 express greatly reduced amounts of p28 and p65 at the non-permissive temperature. These mutants may have defects in one or more viral protease activities. ORF 1b, highly conserved between MHV and IBV, potentially contains polymerase, helicase and zinc finger domains. None of these activities have yet been demonstrated. ORF 1b polypeptides have yet been detected in infected cells.
Asunto(s)
Virus de la Hepatitis Murina/metabolismo , Precursores de Proteínas/metabolismo , Procesamiento Proteico-Postraduccional , Proteínas Virales/metabolismo , Animales , Anticuerpos Antivirales/inmunología , Sistema Libre de Células , Células Cultivadas , Genes Virales/genética , Ratones , Modelos Genéticos , Virus de la Hepatitis Murina/genética , Sistemas de Lectura Abierta/genética , Biosíntesis de Proteínas , Análisis de Secuencia , Especificidad de la Especie , Proteínas Virales/genética , Proteínas Virales/inmunologíaRESUMEN
The effects of a single challenge with 60,000 infective Ostertagia ostertagi larvae on blood and gastrointestinal mucosal gastrin concentrations, gastrin-producing G-cell numbers in the pyloric mucosa and growth of different parts of the gut were investigated in 16, two-and-a-half-month-old calves. Infected calves exhibited a rise in abomasal pH which was accompanied by a 145 per cent increase in wet weight of the fundic mucosa (P < 0.05) and a significant rise in blood total gastrin concentrations (P < 0.01). Circulating little gastrin (G-17) was unaffected. Pyloric mucosal total gastrin concentrations remained unaltered in the infected calves until day 28 when levels fell to 36.9 per cent of control group values (P < 0.01). Pyloric mucosal G-cell numbers declined during the experiment in the infected group. It is suggested that release of previously stored tissue gastrin and not a change in G-cell numbers contributes to the hypergastrinaemia associated with ostertagia infection in the calf.
Asunto(s)
Enfermedades de los Bovinos , Mucosa Gástrica/patología , Gastrinas/metabolismo , Ostertagiasis/veterinaria , Animales , Bovinos , Gastrinas/sangre , Técnicas para Inmunoenzimas , Ostertagia/aislamiento & purificación , Ostertagiasis/sangre , Ostertagiasis/patología , Recuento de Huevos de Parásitos , Pepsinógenos/sangre , Radioinmunoensayo , Valores de ReferenciaRESUMEN
Polypeptide products of MHV-A59 gene 1 have been identified in infected DBT cells and in the products of in vitro translations of genome RNA. In this paper we report the identification in infected cell lysates of a 65-kDa polypeptide (p65) encoded in ORF 1a. Studies on the kinetics of appearance and processing of p65 show that p65 is detectable after p28 but before the appearance of p290, p240 and p50. No homologue of the p65 polypeptide identified in infected cell lysates was immunoprecipitated from in vitro translations of genomic RNA, providing further evidence that in vitro processing of polypeptides encoded in ORF 1a of gene 1 differs from that which occurs late in infection of DBT cells. Although the function of p65 is unknown, two MHV-A59 ts mutants isolated and characterized by Baric et al. (3,4) do not produce detectable levels of p65 at the non-permissive temperature indicating that p65 may play an important role in the virus life cycle.
Asunto(s)
Virus de la Hepatitis Murina/genética , ARN Viral/genética , Proteínas Virales/genética , Animales , Astrocitoma , Ratones , Mutación , Sistemas de Lectura Abierta , Biosíntesis de Proteínas , Procesamiento Proteico-Postraduccional , Temperatura , Células Tumorales Cultivadas , Proteínas Virales/metabolismoRESUMEN
The secretion of insulin-like growth-factor-binding proteins (IGFBPs) and expression of the genes encoding IGFBP-1, IGFBP-2 and IGFBP-3 have been studied in a panel of cell lines derived from breast carcinomas, Wilms' tumour, neuroblastoma, retinoblastoma, colon carcinoma, liver adenocarcinoma, Burkitt's lymphoma and a non-small-cell lung carcinoma. All cell lines, with the exception of the Burkitt's lymphoma cell line, secreted IGFBPs, as detected by affinity labelling. A 34-kDa BP was present in the conditioned media of all IGFBP-secreting cell lines, whereas BPs ranging from 18 kDa to 53 kDa were variably secreted. All IGFBP-secreting cell lines expressed the IGFBP-2 gene as determined by Northern blot analysis. The Wilms' tumour, the neuroblastoma and the retinoblastoma cell line expressed the IGFBP-2 gene only. All other cell lines, with the exception of the Burkitt's lymphoma, expressed the IGFBP-2 gene and, in addition, either the IGFBP-1 gene and/or the IGFBP-3 gene. IGFBP-1 gene expression could be detected by reverse transcriptase polymerase chain reaction only. IGFBP-3 gene expression was detected by Northern blot analysis, but transcripts were less abundant than IGFBP-2 mRNAs. These findings indicate that the expression of multiple BP genes and the secretion of BPs may be a common property of tumour cells.