RESUMEN
A tumor-associated inflammatory response has recently been found to contribute to the considerable interindividual variability in cytotoxic drug clearance seen in cancer patients. Circulating inflammatory markers, such as C-reactive protein (CRP) and interleukin-6 (IL-6), correlate with excessive drug toxicity caused by reduced CYP3A4-mediated metabolism. This article outlines the use of a transgenic mouse model of human CYP3A4 regulation to demonstrate that extrahepatic tumors elicit an inflammatory response, leading to transcriptional repression of the CYP3A4 gene as well as of other drug clearance pathways.
Asunto(s)
Antineoplásicos/farmacocinética , Inhibidores del Citocromo P-450 CYP3A , Citocromo P-450 CYP3A/genética , Neoplasias/genética , Neoplasias/patología , Transcripción Genética/fisiología , Animales , Antineoplásicos/uso terapéutico , Citocromo P-450 CYP3A/metabolismo , Humanos , Inflamación/genética , Inflamación/metabolismo , Tasa de Depuración Metabólica/efectos de los fármacos , Tasa de Depuración Metabólica/fisiología , Ratones , Ratones Transgénicos , Neoplasias/tratamiento farmacológico , Neoplasias/metabolismo , Transcripción Genética/efectos de los fármacos , Transgenes/efectos de los fármacos , Transgenes/fisiología , Ensayos Antitumor por Modelo de Xenoinjerto/métodosRESUMEN
Nonalcoholic steatohepatitis (NASH) and alcoholic liver disease have similar pathological features. Because CYP2E1 plays a key role in alcoholic liver disease with its ability to stimulate lipid peroxidation, we tested the proposal that CYP2E1 could also be a factor in the development of NASH. In a dietary model - mice fed a methionine- and choline-deficient (MCD) diet - liver injury was associated with both induction of CYP2E1 and a 100-fold increase in hepatic content of lipid peroxides. Microsomal NADPH-dependent lipid oxidases contributed to the formation of these lipid peroxides, and in vitro inhibition studies demonstrated that CYP2E1 was the major catalyst. To further define the role of CYP2E1 as an initiator of oxidative stress in NASH, Cyp2e1(-/-)mice were administered the MCD diet. CYP2E1 deficiency neither prevented the development of NASH nor abrogated the increased microsomal NADPH-dependent lipid peroxidation, indicating the operation of a non-CYP2E1 peroxidase pathway. In Cyp2e1(-/-) mice with NASH (but not in wild-type mice), CYP4A10 and CYP4A14 were upregulated. Furthermore, hepatic microsomal lipid peroxidation was substantially inhibited by anti-mouse CYP4A10 antibody in vitro. These results show that experimental NASH is strongly associated with hepatic microsomal lipid peroxidation. CYP2E1, the main enzyme associated with that process in wild-type mice, is not unique among P450 proteins in catalyzing peroxidation of endogenous lipids. We have now identified CYP4A enzymes as alternative initiators of oxidative stress in the liver.
Asunto(s)
Citocromo P-450 CYP2E1/metabolismo , Sistema Enzimático del Citocromo P-450/metabolismo , Hígado Graso/enzimología , Hepatitis/enzimología , Peroxidación de Lípido , Oxigenasas de Función Mixta/metabolismo , Animales , Catálisis , Deficiencia de Colina , Citocromo P-450 CYP2E1/genética , Citocromo P-450 CYP4A , Hígado Graso/patología , Femenino , Expresión Génica , Hepatitis/patología , Metionina/deficiencia , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Microsomas , Pérdida de PesoRESUMEN
In this study we have analyzed the inducible as well as constitutive hepatic expression of Cyp2e1 in a genetic model of obesity and non-insulin dependent (type II) diabetes, the leptin-deficient ob/ob mouse. In obese mice, Cyp2e1 levels were decreased compared to lean littermates. Treatment with leptin increased hepatic Cyp2e1 in obese mice to the levels observed in lean animals, but failed to alter Cyp2e1 expression in lean animals. As expected, leptin also reduced food intake in treated mice compared to saline-treated controls. In obese mice pair-fed the reduced amount of food, there was a significant increase in Cyp2e1 mRNA but no increase in Cyp2e1 protein or enzyme activity. Fasting and administration of acetone and 4-methylpyrazole increased Cyp2e1 mRNA as well as protein and activity in both obese and lean mice. The present data indicate that while Cyp2e1 is still inducible in obese mice by xenobiotics and fasting, full constitutive expression of Cyp2e1 requires leptin to be present. This effect of leptin appears to be at least partly independent of the hypothalamic control of food intake.
Asunto(s)
Citocromo P-450 CYP2E1/biosíntesis , Leptina/metabolismo , Hígado/enzimología , Obesidad/enzimología , Acetona/farmacología , Animales , Citocromo P-450 CYP2E1/genética , Citocromo P-450 CYP2E1/metabolismo , Diabetes Mellitus Tipo 2/enzimología , Diabetes Mellitus Tipo 2/genética , Inducción Enzimática , Ayuno , Femenino , Fomepizol , Regulación de la Expresión Génica/efectos de los fármacos , Leptina/administración & dosificación , Leptina/deficiencia , Ratones , Ratones Endogámicos C57BL , Obesidad/genética , Obesidad/metabolismo , Pirazoles/farmacología , XenobióticosRESUMEN
The cDNAs for two CYP3A genes were isolated from the livers of rats using an RT-PCR approach with CYP3A subfamily-specific primers. Sequence analysis revealed these cDNAs to be identical to CYP3A9, which had previously been isolated from rat brain and nasal epithelium and the recently described CYP3A18. The hepatic expression of both genes was sexually dimorphic. Thus CYP3A18 mRNA levels were 25-fold higher in male livers compared to females, while CYP3A9 showed a reverse pattern with 6-fold higher expression in the liver of females. Exposure of male rats to the female pattern of growth hormone secretion led to an increase in hepatic CYP3A9 mRNA expression and suppressed expression of CYP3A18. These findings indicate that the CYP3A subfamily in rats has both male- and female-specific isoforms which are regulated by growth hormone in a manner similar to some other sexually dimorphic cytochrome P450s.
Asunto(s)
Regulación Enzimológica de la Expresión Génica , Hormona del Crecimiento/farmacología , Caracteres Sexuales , Animales , Clonación Molecular , ADN Complementario/genética , Femenino , Humanos , Recién Nacido , Hígado/enzimología , Masculino , Orquiectomía , Ratas , Ratas Wistar , Análisis de Secuencia de ADN , Distribución TisularRESUMEN
In this correspondence, a simple one-dimensional (1-D) differencing operation is applied to bilevel images prior to block coding to produce a sparse binary image that can be encoded efficiently using any of a number of well-known techniques. The difference image can be encoded more efficiently than the original bilevel image whenever the average run length of black pixels in the original image is greater than two. Compression is achieved because the correlation between adjacent pixels is reduced compared with the original image. The encoding/decoding operations are described and compression performance is presented for a set of standard bilevel images.
RESUMEN
A gene in equine herpesvirus 1 (EHV-1, equine abortion virus) homologous to the glycoprotein H gene of herpes simplex virus (HSV) was identified and characterised by its nucleotide and derived amino acid sequence. The EHV-1 gH gene is located at 0.47-0.49 map units and contains an open reading frame capable of specifying a polypeptide of 848 amino acids, including N- and C-terminal hydrophobic domains consistent with signal and membrane anchor regions respectively, and 11 potential sites for N-glycosylation. Alignment of the amino acid sequence with those published for HSV gH, varicella zoster virus gpIII, Epstein Barr virus gp85 and human cytomegalovirus p86 shows similarity of the EHV gene with the 2 other alpha-herpesviruses over most of the polypeptide, but only the C-terminal half could be aligned for all 5 viruses. The identical positioning of 6 cysteine residues and a number of highly conserved amino acid motifs supports a common evolutionary origin of this gene and is consistent with its role as an essential glycoprotein of the herpesvirus family. An origin of replication is predicted to occur at approximately 300 nucleotides downstream of the EHV-1 gH coding region, on the basis of similarity to other herpesvirus origins.
Asunto(s)
Genes Virales , Herpesvirus Équido 1/genética , Homología de Secuencia de Ácido Nucleico , Simplexvirus/genética , Proteínas del Envoltorio Viral/genética , Secuencia de Aminoácidos , Secuencia de Bases , Replicación del ADN , ADN Viral , Datos de Secuencia Molecular , Mapeo RestrictivoRESUMEN
Nd:glass optical waveguides were fabricated on silicon substrates by rf sputtering. Lasing was achieved at a wavelength of 1.05 microm with a dye laser pump threshold of approximately 100 m W.
RESUMEN
A gene in equine herpesvirus 1 (EHV-1; equine abortion virus) equivalent to the gB glycoprotein gene of herpes simplex virus (HSV) has been identified by DNA hybridization and nucleotide sequencing. A 4.3 kbp EHV-1 PstI-ClaI sequence (0.40 to 0.43 map units) contained an open reading frame flanked by appropriate control elements and was capable of encoding a polypeptide of 980 amino acids. This had 50 to 60% identity over a 617 amino acid conserved region with the gB gene products of HSV and three other alphaherpesviruses, and 20 to 30% identity with those of human cytomegalovirus and Epstein-Barr virus. Analysis of the amino acid sequence predicts a long signal peptide, hydrophobic and hydrophilic domains and N-glycosylation sites, and has identified a probable internal proteolytic cleavage site. The EHV-1 gB open reading frame appears to be overlapped at its 5' end by 135 nucleotides of the 3' end of an upstream open reading frame the potential translation product of which has approximately 50% identity with HSV gene ICP 18.5 and VZV gene 30 products.
Asunto(s)
Genes Virales , Glicoproteínas/genética , Herpesviridae/genética , Herpesvirus Équido 1/genética , Simplexvirus/genética , Proteínas del Envoltorio Viral/genética , Secuencia de Aminoácidos , Secuencia de Bases , ADN Viral/genética , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Péptidos/genética , Plásmidos , Homología de Secuencia de Ácido NucleicoRESUMEN
We have identified the equine herpesvirus 1 (EHV-1) thymidine kinase gene (TK) by DNA-mediated transformation and by DNA sequencing. Alignment of the amino acid sequence of the EHV-1 TK with the TKs from 3 other herpesviruses revealed regions of homology, some of which correspond to the previously identified substrate binding sites, while others have as yet, no assigned function. In particular, the strict conservation of an aspartate within the proposed nucleoside binding site suggests a role in ATP binding for this residue. Comparison of 5 herpes TKs with the thymidylate kinase of yeast revealed significant similarity which was strongest in those regions important to catalytic activity of the herpes TKs, and, therefore we propose that the herpes TK may be derived from a cellular thymidylate kinase. The implications for the evolution of enzyme activities within a pathway of nucleotide metabolism are discussed.
Asunto(s)
Secuencia de Bases , Herpesviridae/enzimología , Herpesvirus Équido 1/enzimología , Nucleósido-Fosfato Quinasa/genética , Fosfotransferasas/genética , Homología de Secuencia de Ácido Nucleico , Timidina Quinasa/genética , Secuencia de Aminoácidos , Animales , Línea Celular Transformada , Genes , Herpesvirus Équido 1/genética , Ratones , Datos de Secuencia Molecular , Saccharomyces cerevisiae/enzimología , Timidina Quinasa/aislamiento & purificaciónRESUMEN
The genome of an Australian isolate of equine herpesvirus type 1 (equine abortion virus) has been analysed using the restriction endonucleases EcoRI, BglII and BamHI, and a physical map constructed. Terminal fragments were identified by exonuclease treatments, and linkage of fragments was deduced by a combination of single- and double-digest experiments and cross-blot hybridizations. The genome has a mol. wt. of 100 x 10(6) and is comprised of a short unique region bounded by repetitive sequences, which is present in both orientations in approximately equal amounts in the DNA population, and a long unique region existing in only one orientation.
Asunto(s)
Proteínas Bacterianas , ADN Viral/análisis , Desoxirribonucleasas de Localización Especificada Tipo II , Genes Virales , Herpesviridae/genética , Herpesvirus Équido 1/genética , Enzimas de Restricción del ADN , Desoxirribonucleasa BamHI , Desoxirribonucleasa EcoRI , Peso Molecular , Hibridación de Ácido Nucleico , Secuencias Repetitivas de Ácidos NucleicosRESUMEN
A 35-year-old white female is presented for case review. According to H. M. Worth, the classification polyostotic fibrous dysplasia, leontiasis ossea type, would be appropriate. Bone lesions are present in the skull, all facial bones, ribs, pelvic girdle and extremities. The patient's oral/maxillofacial appearance is characterized by massive bony protuberances, hypertelorism and malocclusion, resulting in a grossly distorted leonine mask-like facies. Serum alkaline phosphatase levels are high and, in spite of five facial operations, the patient's disease process continues.
Asunto(s)
Huesos Faciales/patología , Displasia Fibrosa Ósea/patología , Displasia Fibrosa Poliostótica/patología , Adulto , Femenino , Humanos , Enfermedades Mandibulares/patología , Enfermedades Maxilares/patología , Cirugía PlásticaRESUMEN
This report described primary malignant melanoma of the maxilla in the region of the palate and gingiva, the two most common locations of oral melanoma. It fulfilled the three criteria for a primary lesion as described by Greene and others, that is, malignant melanoma was demonstrated in the oral mucosa by biopsy examination, intraepidermal activity was present, and melanoma was not present at any other site. Treatment consisted of partial maxillectomy and the immediate use of maxillofacial prosthetics to offer the patient the maximum comfort in early rehabilitation.
Asunto(s)
Neoplasias Gingivales/patología , Neoplasias Maxilares/patología , Melanoma/patología , Neoplasias Palatinas/patología , Diagnóstico Diferencial , Humanos , Masculino , Persona de Mediana Edad , Invasividad NeoplásicaRESUMEN
Six hundred cases of cleidocranial dysostosis have been reported since the disorder was first described in 1898. This is the first case reported with cystic involvement.
Asunto(s)
Displasia Cleidocraneal/complicaciones , Quiste Dentígero/complicaciones , Enfermedades Mandibulares/complicaciones , Adolescente , Alveolectomía , Trasplante Óseo , Displasia Cleidocraneal/diagnóstico por imagen , Quiste Dentígero/diagnóstico por imagen , Quiste Dentígero/cirugía , Humanos , Masculino , Enfermedades Mandibulares/diagnóstico por imagen , Enfermedades Mandibulares/cirugía , Radiografía Panorámica , Trasplante HomólogoRESUMEN
Dermoid cysts of the floor of the mouth comprise aproximately 0.01 per cent of all oral cystic lesions. This case is presented because of its large size, its unusual location, and the difficulty encountered in removing the mass.