RESUMEN
We show that the enhancement of the saturation scale in large nuclei relative to the proton is significantly influenced by the effects of quantum evolution and the impact parameter dependence of dipole cross sections in high energy QCD. We demonstrate that there is a strong A dependence in diffractive deeply inelastic scattering and discuss its sensitivity to the measurement of the recoil nucleus.
RESUMEN
Vascular endothelial growth factor receptor-3 (VEGFR-3/Flt4) binds two known members of the VEGF ligand family, VEGF-C and VEGF-D, and has a critical function in the remodelling of the primary capillary vasculature of midgestation embryos. Later during development, VEGFR-3 regulates the growth and maintenance of the lymphatic vessels. In the present study, we have isolated and cultured stable lineages of blood vascular and lymphatic endothelial cells from human primary microvascular endothelium by using antibodies against the extracellular domain of VEGFR-3. We show that VEGFR-3 stimulation alone protects the lymphatic endothelial cells from serum deprivation-induced apoptosis and induces their growth and migration. At least some of these signals are transduced via a protein kinase C-dependent activation of the p42/p44 MAPK signalling cascade and via a wortmannin-sensitive induction of Akt phosphorylation. These results define the critical role of VEGF-C/VEGFR-3 signalling in the growth and survival of lymphatic endothelial cells. The culture of isolated lymphatic endothelial cells should now allow further studies of the molecular properties of these cells.
Asunto(s)
Apoptosis/fisiología , Factores de Crecimiento Endotelial/farmacología , Factores de Crecimiento Endotelial/fisiología , Endotelio Vascular/fisiología , Endotelio/fisiología , Sistema Linfático/fisiología , Sistema de Señalización de MAP Quinasas/fisiología , Proteínas Tirosina Quinasas Receptoras/fisiología , Receptores de Factores de Crecimiento/fisiología , Apoptosis/efectos de los fármacos , Técnicas Biosensibles , Capilares/embriología , Capilares/fisiología , División Celular , Movimiento Celular , Supervivencia Celular , Células Cultivadas , Endotelio/citología , Endotelio Vascular/citología , Activación Enzimática , Humanos , Cinética , Sistema Linfático/citología , Microcirculación/fisiología , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Proteína Quinasa C/metabolismo , ARN Mensajero/genética , Proteínas Tirosina Quinasas Receptoras/genética , Receptores de Factores de Crecimiento/genética , Receptores de Factores de Crecimiento Endotelial Vascular , Piel/irrigación sanguínea , Venas Umbilicales , Factor C de Crecimiento Endotelial Vascular , Factor D de Crecimiento Endotelial Vascular , Receptor 3 de Factores de Crecimiento Endotelial VascularRESUMEN
Few data on the influence of lymphatic microvessel density (MVD) on survival in cancer are available since until recently there was no reliable immunohistological marker for lymphatic endothelium. Using an antibody staining podoplanin, a novel marker for lymphatic endothelium, lymphatic MVD in tissue samples of 85 patients with cervical cancer classification pT1b treated by radical hysterectomy was investigated. Survival was determined using univariate and multivariate analyses. Lymphatic MVD was also compared to MVD assessed by immunostaining against factor VIII-related antigen, which is considered a marker for blood vessels. Patients with >5 lymphatic microvessels/0.25 mm(2) field had significantly better overall survival (mean 91.8 months) than those with < or =5 lymphatic microvessels/field in univariate analysis (mean 113 months) (p = 0.0105, log-rank test). In multivariate analysis, lymphatic node involvement (p =0.0183), vessel infiltration (p =0.0158) and lymphatic MVD (p =0.0269) remained independent prognostic factors. No correlation between lymphatic MVD and various clinical and histopathological parameters was observed. Correlation between lymphatic MVD and MVD assessed by immunostaining against factor VIII was only weak (p = 0.004, r = 0.312, Spearman's coefficient of correlation). Our results suggest that increased lymphatic MVD is associated with favorable prognosis in early-stage cervical cancer.
Asunto(s)
Ganglios Linfáticos/patología , Microcirculación/patología , Neoplasias del Cuello Uterino/diagnóstico , Adenocarcinoma/irrigación sanguínea , Adenocarcinoma/diagnóstico , Adenocarcinoma/metabolismo , Braquiterapia , Carcinoma Adenoescamoso/irrigación sanguínea , Carcinoma Adenoescamoso/diagnóstico , Carcinoma Adenoescamoso/metabolismo , Carcinoma de Células Escamosas/irrigación sanguínea , Carcinoma de Células Escamosas/diagnóstico , Carcinoma de Células Escamosas/metabolismo , Femenino , Humanos , Inmunohistoquímica , Ganglios Linfáticos/irrigación sanguínea , Ganglios Linfáticos/metabolismo , Metástasis Linfática , Glicoproteínas de Membrana/biosíntesis , Microcirculación/metabolismo , Análisis Multivariante , Invasividad Neoplásica , Pronóstico , Factores de Tiempo , Neoplasias del Cuello Uterino/irrigación sanguínea , Neoplasias del Cuello Uterino/metabolismo , Factor de von Willebrand/biosíntesisRESUMEN
Lymphovascular space invasion was shown to play a key role in the progression of cervical cancer. Because of the absence of a specific marker for lymphatic vessels, earlier studies could not reliably distinguish between blood and lymphatic vessel invasion. By immunostaining for podoplanin, a novel marker for lymphatic endothelium, and for factor VIII-related antigen, we determined lymphatic and blood vessel invasion in tissue samples of 98 patients with cervical cancer pT1b treated by radical hysterectomy. Eleven (11.2%) specimens showed invasion of blood vessels, 20 (20.4%) showed invasion of lymphatic vessels, and 15 (15.3%) showed invasion of blood and lymphatic vessels. There was a strong association of lymphatic vessel invasion and lymph node involvement (P < 0.001). In univariate analysis, both blood and lymphatic vessel invasion failed to reach a statistically significant influence on overall survival, but a significant influence on disease-free survival was found (P = 0.0002 and P < 0.0001, respectively). In multivariate analysis of disease-free survival, only blood vessel invasion remained statistically significant (P = 0.0457). Lymphatic vessel invasion reached significance when lymph node status was excluded from the model (P = 0.0025). Both lymphatic vessel and blood vessel invasion occur frequently in early-stage cervical cancer. Determination of the vessel status may be of clinical importance because it signifies the risk of recurrent disease.
Asunto(s)
Biomarcadores/análisis , Sistema Linfático/metabolismo , Glicoproteínas de Membrana/metabolismo , Neovascularización Patológica/metabolismo , Neoplasias del Cuello Uterino/irrigación sanguínea , Factor de von Willebrand/metabolismo , Adulto , Biopsia , Femenino , Humanos , Histerectomía , Técnicas para Inmunoenzimas , Escisión del Ganglio Linfático , Metástasis Linfática , Análisis Multivariante , Análisis de Supervivencia , Neoplasias del Cuello Uterino/patología , Neoplasias del Cuello Uterino/cirugíaRESUMEN
BACKGROUND: The influence of lymphatic microvessel density (MVD) on survival in epithelial ovarian cancer is still unknown, owing to the fact that until recently no reliable immunohistologic markers for lymphatic endothelium were available. MATERIALS AND METHODS: By using a polyclonal antibody staining podoplanin, a novel marker for lymphatic endothelium, lymphatic MVD in tissue samples of 90 patients with epithelial ovarian cancer treated by radical surgery and chemotherapy was investigated. Survival analysis was performed using univariate and multivariate analysis. Furthermore, lymphatic MVD was compared to MVD assessed by CD34 immunostaining. RESULTS: Lymphatic MVD was significantly lower than CD34 MVD (p < 0.0001). There was no significant association between lymphatic MVD and various histological and clinical parameters. Lymphatic MVD had no influence on overall survival and disease free survival (p = 0.4627 and p = 0.4337, respectively; log-rank test). CONCLUSION: The formation of lymphatic vessels has no influence on the progression of epithelial ovarian cancer.
Asunto(s)
Endotelio Linfático/irrigación sanguínea , Mesotelioma/irrigación sanguínea , Neoplasias Ováricas/irrigación sanguínea , Factores de Edad , Animales , Biomarcadores , Endotelio Linfático/patología , Femenino , Estudios de Seguimiento , Humanos , Glicoproteínas de Membrana/análisis , Mesotelioma/química , Mesotelioma/clasificación , Mesotelioma/patología , Microcirculación/patología , Persona de Mediana Edad , Estadificación de Neoplasias , Neoplasias Ováricas/química , Neoplasias Ováricas/clasificación , Neoplasias Ováricas/patología , Pronóstico , Conejos , RecurrenciaRESUMEN
Despite intensive research over the past decade, the exact lineage relationship of Kaposi's sarcoma (KS) tumor cells has not yet been settled. In the present study, we investigated the expression of two markers for lymphatic endothelial cells (EC), ie, vascular endothelial growth factor receptor-3 (VEGFR-3) and podoplanin, in AIDS and classic KS. Both markers were strongly expressed by cells lining irregular vascular spaces in early KS lesions and by tumor cells in advanced KS. Double-staining experiments by confocal laser microscopy established that VEGFR-3-positive and podoplanin-positive cell populations were identical and uniformly expressed CD31. By contrast, these cells were negative for CD45, CD68, and PAL-E, excluding their hemopoietic and blood vessel endothelial cell nature. Podoplanin expression in primary KS tumor lysates was confirmed by Western blot analysis. Both splice variants of VEGFR-3 were found in KS-tumor-derived RNA by RT-PCR. In contrast to KS tumor cells in situ, no expression of VEGFR-3 and podoplanin was detected in any of four KS-derived spindle cell cultures and in one KS-derived autonomously growing cell line (KS Y-1). Our findings that KS tumor cells express two lymphatic EC markers in situ strongly suggest that they are related to or even derived from the lymphatic EC lineage. Lack of these antigens on cultured cells derived from KS lesions indicates that they might not represent tumor cells that grow in tissue culture, but rather other cell types present in KS lesions.
Asunto(s)
Sistema Linfático/citología , Sistema Linfático/metabolismo , Glicoproteínas de Membrana/metabolismo , Proteínas Tirosina Quinasas Receptoras/metabolismo , Receptores de Superficie Celular/metabolismo , Sarcoma de Kaposi/metabolismo , Sarcoma de Kaposi/patología , Western Blotting , Línea Celular , Endotelio/citología , Endotelio/metabolismo , Humanos , ARN Mensajero/metabolismo , Proteínas Tirosina Quinasas Receptoras/genética , Receptores de Superficie Celular/genética , Células Tumorales Cultivadas/metabolismo , Receptor 3 de Factores de Crecimiento Endotelial VascularAsunto(s)
Glomérulos Renales/citología , Glicoproteínas de Membrana/fisiología , Inmunoglobulina G/inmunología , Enfermedades Renales/inmunología , Glicoproteínas de Membrana/química , Glicoproteínas de Membrana/inmunología , Peso Molecular , Nefrosis/inducido químicamente , Proteinuria/inmunología , Puromicina AminonucleósidoRESUMEN
Angiosarcomas apparently derive from blood vessel endothelial cells; however, occasionally their histological features suggest mixed origin from blood and lymphatic endothelia. In the absence of specific positive markers for lymphatic endothelia the precise distinction between these components has not been possible. Here we provide evidence by light and electron microscopic immunohistochemistry that podoplanin, a approximately 38-kd membrane glycoprotein of podocytes, is specifically expressed in the endothelium of lymphatic capillaries, but not in the blood vasculature. In normal skin and kidney, podoplanin colocalized with vascular endothelial growth factor receptor-3, the only other lymphatic marker presently available. Complementary immunostaining of blood vessels was obtained with established endothelial markers (CD31, CD34, factor VIII-related antigen, and Ulex europaeus I lectin) as well as podocalyxin, another podocytic protein that is also localized in endothelia of blood vessels. Podoplanin specifically immunolabeled endothelia of benign tumorous lesions of undisputed lymphatic origin (lymphangiomas, hygromas) and was detected there as a 38-kd protein by immunoblotting. As paradigms of malignant vascular tumors, poorly differentiated (G3) common angiosarcomas (n = 8), epitheloid angiosarcomas (n = 3), and intestinal Kaposi's sarcomas (n = 5) were examined for their podoplanin content in relation to conventional endothelial markers. The relative number of tumor cells expressing podoplanin was estimated and, although the number of cases in this preliminary study was limited to 16, an apparent spectrum of podoplanin expression emerged that can be divided into a low-expression group in which 0-10% of tumor cells contained podoplanin, a moderate-expression group with 30-60% and a high-expression group with 70-100%. Ten of eleven angiosarcomas and all Kaposi's sarcomas showed mixed expression of both lymphatic and blood vascular endothelial phenotypes. By double labeling, most podoplanin-positive tumor cells coexpressed endothelial markers of blood vessels, whereas few tumor cells were positive for individual markers only. From these results we conclude that (1) podoplanin is a selective marker of lymphatic endothelium; (2) G3 angiosarcomas display a quantitative spectrum of podoplanin-expressing tumor cells; (3) in most angiosarcomas, a varying subset of tumor cells coexpresses podoplanin and endothelial markers of blood vessels; and (4) all endothelial cells of Kaposi's sarcomas expressed the lymphatic marker podoplanin.
Asunto(s)
Endotelio Linfático/metabolismo , Endotelio Vascular/metabolismo , Hemangiosarcoma/metabolismo , Glicoproteínas de Membrana/metabolismo , Neoplasias Vasculares/metabolismo , Antígenos CD34/metabolismo , Biomarcadores de Tumor/análisis , Capilares/metabolismo , Capilares/patología , Células Cultivadas , Endotelio Linfático/patología , Endotelio Vascular/patología , Factor VIII/metabolismo , Técnica del Anticuerpo Fluorescente Indirecta , Hemangiosarcoma/irrigación sanguínea , Hemangiosarcoma/patología , Humanos , Técnicas para Inmunoenzimas , Glicoproteínas de Membrana/inmunología , Molécula-1 de Adhesión Celular Endotelial de Plaqueta/metabolismo , Proteínas Tirosina Quinasas Receptoras/metabolismo , Receptores de Superficie Celular/metabolismo , Sialoglicoproteínas/metabolismo , Receptor 3 de Factores de Crecimiento Endotelial Vascular , Neoplasias Vasculares/irrigación sanguínea , Neoplasias Vasculares/patologíaRESUMEN
AIMS: Angiosarcomas apparently derive from endothelia of the blood vasculature, however occasionally their histologic features suggest mixed origin from blood and lymphatic endothelia. In the absence of specific positive markers for lymphatic endothelia the precise distinction between these components was not possible so far. Here we provide evidence that podoplanin, a approximately 38 kD membrane glycoprotein of podocytes is a specific marker of lymphatic endothelium that was used to identify the relative fraction of tumor cells with lymphatic or blood vascular endothelial phenotype in vascular tumors. METHODS: Podoplanin was localized in normal human skin and kidney cortex by immunohistochemistry on paraffin sections, double immunofluorescence on frozen sections with PAL-E, immunoelectron microscopy and by immunoblotting. 45 vascular tumors (29 benign lesions, 11 angiosarcomas and 5 gastrointestinal Kaposi's sarcomas) were evaluated for podoplanin expression. Complementary staining was obtained with established endothelial markers (CD 31, CD 34, Factor VIII related antigen, UEA I) and with podocalyxin, another podocytic protein mainly present in endothelia of blood vessels. RESULTS: In human tissues podoplanin is specifically expressed in the endothelium of lymphatics, but not in blood vasculature or in hemangiomas. This expression is preserved in endothelia of all benign lymphatic tumorous lesions and all Kaposi's sarcomas examined. By contrast 10 out of 11 G3 angiosarcomas contained only variable fractions of podoplanin-expressing tumor cells. Most tumor cells coexpressed podoplanin and markers of blood vessel phenotype. CONCLUSIONS: (1) Podoplanin is a selective marker of lymphatic endothelium; (2) G3 angiosarcomas display a quantitative spectrum of podoplanin-expressing tumor cells; (3) In the majority of angiosarcomas tumor cells coexpress podoplanin and endothelial markers of blood vessels; (4) All endothelial cells of Kaposi's sarcomas expressed the lymphatic marker podoplanin.
Asunto(s)
Hemangiosarcoma/patología , Sistema Linfático/patología , Glicoproteínas de Membrana/análisis , Biomarcadores/análisis , Endotelio/patología , Humanos , Corteza Renal/citología , Valores de Referencia , Sensibilidad y Especificidad , Piel/citologíaRESUMEN
The genotoxic properties of 2',2'-difluorodeoxycytidine (dFdC) were characterised using diploid, mortal low-passage fibroblasts (LPF cells) and the spontaneously transformed fibroblast cell line V79. In both cell types, incorporation of dFdC into the DNA led to an increase of DNA single-strand breaks evaluated by an in situ nick translation assay and to an accumulation of cells in the S-phase of the cell cycle. At concentrations below those leading to cell cycle arrest, dFdC neither induced sister chromatid exchange (SCE) nor structural chromosome aberrations in LPF cells, whereas V79 cells accumulated SCEs as well as chromosome breaks over a broad dose range. In LPF cells treated with dFdC, chromosomal alterations were detected by the micronucleus assay within a narrow concentration range, whereas in V79 cells, a dose-dependent increase in the appearance of micronuclei was seen up to cytotoxic concentrations. In addition, V79 cells went into apoptosis, as evaluated by nuclear fragmentation and condensation, whereas this phenomenon was not detectable in LPF cells.
Asunto(s)
Antimetabolitos Antineoplásicos/toxicidad , Desoxicitidina/análogos & derivados , Mutágenos/toxicidad , Apoptosis/efectos de los fármacos , Ciclo Celular/efectos de los fármacos , División Celular/efectos de los fármacos , Línea Celular Transformada , Células Cultivadas , Aberraciones Cromosómicas , Daño del ADN , Desoxicitidina/toxicidad , Humanos , Pruebas de Micronúcleos , Intercambio de Cromátides Hermanas/efectos de los fármacos , GemcitabinaRESUMEN
Common chimpanzees (Pan troglodytes) infected with hepatitis C virus (HCV) show a disease progression similar to that observed for human patients. Although most infected animals develop a chronic hepatitis, virus persistence is associated with an ongoing immune response, for which the beneficial or detrimental effects are uncertain. Lines of virus-specific cytotoxic CD8+ T lymphocytes (CTL) have been previously established from liver biopsies of two common chimpanzees chronically infected with HCV-1. The viral epitopes recognized by six lines of CTL have been defined using synthetic peptides and shown to consist of 8 to 9-residue peptides derived from various viral proteins. Five of the epitopes derive from sequences that vary among strains of HCV. The majority of the corresponding variant epitopes from different HCV strains were either recognized less efficiently or not at all by the CTL, suggesting their response may have limited potential for controlling replication of HCV variants. Complementary DNAs encoding class I alleles of the two common chimpanzees, Patr-A, -B, and -C were cloned, sequenced, and transfected individually into a class I-deficient human cell line. Analysis of peptide presentation by the class I transfectants to CTL identified the Patr class I allotypes that present the six epitopes defined here and an additional epitope defined previously. The assignment of epitopes to class I allotypes based upon analysis of the transfected cells correlates precisely with the segregation of antigen-presenting function within a panel of common chimpanzee cell lines and the expression of class I heavy chains as defined by isoelectric focusing. Five of the HCV-1 epitopes are presented by Patr-B allotypes, two epitopes are presented by a Patr-A allotype, and none is presented by Patr-C allotypes.
Asunto(s)
Presentación de Antígeno , Linfocitos T CD8-positivos/inmunología , Hepacivirus/inmunología , Antígenos de Histocompatibilidad Clase I/inmunología , Pan troglodytes/inmunología , Linfocitos T Citotóxicos/inmunología , Secuencia de Aminoácidos , Animales , Enfermedad Crónica , Epítopos/inmunología , Antígenos de la Hepatitis C/inmunología , Hígado/citología , Hígado/inmunología , Datos de Secuencia Molecular , Oligopéptidos/inmunología , Fragmentos de Péptidos/inmunología , Homología de Secuencia de Aminoácido , Especificidad de la EspecieRESUMEN
A cytotoxic T lymphocyte (CTL) line, derived from the liver of a common chimpanzee (Pan troglodytes) with hepatitis C, specifically recognized a hepatitis C viral 9-mer peptide (KHP-DATYSR in single-letter amino acid code) bound by the major histocompatibility complex (MHC) class I molecule, Patr-A04. This same CTL line also recognized the identical peptide bound by a structurally different class I molecule, Papa-A06, derived from the separate chimpanzee species, Pan paniscus or pygmy chimpanzee. These class I allotypes differ by six amino acids but, in spite of the structural differences, share the same antigen-presenting function. This is the first observation of antigen presentation to a given T cell receptor by different MHC class I allotypes from separate species.
Asunto(s)
Presentación de Antígeno , Antígenos de la Hepatitis C/inmunología , Antígenos de Histocompatibilidad Clase I/inmunología , Pan troglodytes/inmunología , Péptidos/inmunología , Animales , Linfocitos B/citología , Linfocitos B/inmunología , Línea Celular , Citotoxicidad Inmunológica , Antígenos de Histocompatibilidad Clase I/genética , Antígenos de Histocompatibilidad Clase I/aislamiento & purificación , Focalización Isoeléctrica , Pan troglodytes/clasificación , Pan troglodytes/genética , Especificidad de la Especie , Linfocitos T Citotóxicos/citología , Linfocitos T Citotóxicos/inmunologíaRESUMEN
Daudi, a lymphoblastoid B cell line derived from an African Burkitt lymphoma does not express HLA-A,B,C antigens at the cell surface. Although HLA-A,B,C heavy chains are made normally they do not assemble into functional molecules because beta 2-microglobulin is absent. Previous serological analysis of somatic cell hybrids indicated that the HLA haplotypes of Daudi encoded HLA-A1, A10(A26), B17, and B16(38) antigens. Here we describe the application of molecular methods: ARMS-PCR, cDNA cloning and sequencing, immunoprecipitation and gel electrophoresis, to define the class I genotype of the Daudi cell line which is HLA-A*0102, A*6601, B*5801, B*5802, Cw*0302 and Cw*0602. With the exception of the B38 antigen, which is not a product of the alleles defined, the genotype is consistent with the serological description. Two previously undiscovered alleles emerged from this analysis: A*0102 and B*5802. The A*0102 allele differs from A*0101 by 5 nucleotide substitutions within exon 2 where it has a motif shared with A*30 alleles; the B*5802 allele differs from B*5801 by 3 substitutions in exon 3 where it has a motif shared with B*14 alleles. Subtyping HLA-A1 alleles showed A*0102 was well represented amongst individuals typed serologically as A1 in an African population but was absent from caucasoids. B*5802 has been found in a second individual. Thus the novel A and B alleles are not specific to the Daudi tumor. Overall, this analysis of a single East African cell illustrates the power of molecular methods to define new class I HLA alleles in non-caucasoid populations.
Asunto(s)
Genes MHC Clase I/genética , Antígenos HLA-A/genética , Antígenos HLA-B/genética , Células Tumorales Cultivadas/inmunología , África Oriental , Alelos , Secuencia de Bases , Población Negra/genética , ADN/sangre , Frecuencia de los Genes , Antígenos HLA-A/clasificación , Antígenos HLA-B/clasificación , Antígenos HLA-C/clasificación , Antígenos HLA-C/genética , Humanos , Datos de Secuencia Molecular , Reacción en Cadena de la PolimerasaRESUMEN
A protein binding to a minor-group human rhinovirus (HRV2) was purified from HeLa cell culture supernatant. The amino acid sequences of tryptic peptides showed identity with the human low density lipoprotein (LDL) receptor (LDLR). LDL and HRV2 mutually competed for binding sites on human fibroblasts. Cells down-regulated for LDLR expression yielded much less HRV2 upon infection than cells with up-regulated LDLR. Virus also bound to the large subunit of the alpha 2-macroglobulin receptor/LDLR-related protein (alpha 2MR/LRP). LDLR-deficient fibroblasts yielded considerably less virus in the presence of receptor-associated protein (RAP), providing evidence that alpha 2MR/LRP also acts as a minor group HRV receptor.
Asunto(s)
Receptores de LDL/metabolismo , Receptores Virales/metabolismo , Rhinovirus/metabolismo , Secuencia de Aminoácidos , Unión Competitiva , Células Cultivadas , Fibroblastos/metabolismo , Fibroblastos/microbiología , Células HeLa , Humanos , Hiperlipoproteinemia Tipo II/metabolismo , Hiperlipoproteinemia Tipo II/microbiología , Datos de Secuencia Molecular , Fragmentos de Péptidos/genética , Receptores de LDL/clasificación , Receptores de LDL/genética , Receptores Virales/genéticaRESUMEN
A mammalian cell infected with a human rhinovirus or enterovirus has a much reduced capability to translate capped mRNAs (the host cell shutoff), while still allowing translation of uncapped viral RNA. Biochemical and genetic evidence suggests that the viral proteinase 2A induces cleavage of the eukaryotic initiation factor (eIF) 4 gamma (also known as p220) component of eIF-4 (formerly called eIF-4F). However, neither the mechanism underlying the specific proteolysis of eIF-4 gamma nor the influence of this cleavage on the translation of capped mRNAs has been clarified. Such studies have been hampered by a lack of large quantities of a purified 2A proteinase. Therefore, the mature proteinases 2A of human rhinovirus 2 and coxsackievirus B4 were expressed in soluble form in Escherichia coli. A four-step purification protocol was developed; 1 mg of highly purified 2A proteinase per gram wet weight of E. coli was obtained. Both enzymes cleaved directly eIF-4 gamma as part of the purified eIF-4 complex. Addition of HRV2 2A proteinase to HeLa cell cytoplasmic translation extracts resulted in eIF-4 gamma cleavage and drastically reduced the translation of capped mRNA; addition of purified eIF-4 restored translation to the initial level. However, translation of a reporter gene driven by the 5'-untranslated region of human rhinovirus 2 was translated 2-3-fold more efficiently in the presence of HRV2 2A proteinase.
Asunto(s)
Cisteína Endopeptidasas/metabolismo , Factores de Iniciación de Péptidos/metabolismo , Picornaviridae/enzimología , Biosíntesis de Proteínas/efectos de los fármacos , Proteínas Virales , Secuencia de Aminoácidos , Cisteína Endopeptidasas/farmacología , Escherichia coli/genética , Factor 4F Eucariótico de Iniciación , Expresión Génica , Células HeLa , Humanos , Datos de Secuencia Molecular , Factores de Iniciación de Péptidos/farmacología , Péptidos/química , Péptidos/metabolismo , Plásmidos , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacología , Especificidad por Sustrato , Transformación BacterianaRESUMEN
To test the value of currently proposed angiographic categorizations of vein of Galen malformations and a hypothesis regarding the causes of vein of Galen malformations and of accompanying hydrocephalus, as well as to assess the relative utility of MR imaging and CT in clinical evaluation, we reviewed the clinical and radiologic records of 34 patients with vein of Galen malformations. Patients were divided into two groups on the basis of the angiographic demonstration of either an arteriovenous malformation nidus or a direct arteriovenous fistula to the wall of the vein of Galen or one of its tributaries. Patients with such a nidus (n = 17) could be distinguished from those with arteriovenous fistulas alone (n = 17) on the basis of age at presentation (p less than .01) and presenting symptoms. Venous constraints, thought to be etiologically important, were identified in 31 of 34 patients. The presence or absence of hydrocephalus was explainable by mass effect in only 24 of 32 patients. In seven of 32 cases, no obvious mass effect was seen in the presence of hydrocephalus, but arteriographic evidence of venous hypertension was present in all patients with hydrocephalus. MR provided improved depiction of both arterial and venous anatomy as compared with CT. Parenchymal abnormalities were uncommon. No patients had subarachnoid hemorrhages. We conclude that MR is superior to CT in the clinical evaluation of vein of Galen malformations, that the angiographic finding of a nidus separates patients with vein of Galen malformations into clinical and therapeutically relevant groups, and that simple mass effect on the aqueduct is not an adequate explanation for all cases of hydrocephalus in patients with this disease.
Asunto(s)
Angiografía Cerebral , Venas Cerebrales/anomalías , Imagen por Resonancia Magnética , Tomografía Computarizada por Rayos X , Venas Cerebrales/diagnóstico por imagen , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Estudios RetrospectivosRESUMEN
The distributions of the cerebral gray matter, the white matter, and the intracranial cerebrospinal fluid (CSF) were measured in 14 patients with Alzheimer disease (AD) and in 14 healthy control subjects. The measurements, derived from two specifically designed magnetic resonance inversion-recovery sequences, compensate for partial signal averaging. The percentage of the gray matter in the brains of AD patients (44.9% +/- 4.4) was significantly lower than in control subjects (50.2% +/- 3.2). The most significant reduction (P less than .001) occurred in the temporal lobes (13.8%) and a central region (12.8); the reduction in frontal lobe (11.2%) and occipital lobe (9.2%) was also statistically significant (P less than .01). There was an increase in the CSF volume in the temporal, occipital, and frontal regions; no region showed a significant difference in the white matter content. The findings of diffuse changes and temporal lobe involvement in AD are consistent with pathologic observations of cortical cell loss.
Asunto(s)
Enfermedad de Alzheimer/diagnóstico , Encéfalo/patología , Imagen por Resonancia Magnética/métodos , Anciano , Enfermedad de Alzheimer/líquido cefalorraquídeo , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Lóbulo Temporal/patologíaRESUMEN
Corticosteroids are commonly used in the treatment of connective tissue diseases such as systemic lupus erythematosus. Although they are usually efficacious, osteoporosis leading to spine compression fractures is not uncommon. In this case report, we describe an elderly patient with systemic lupus erythematosus on long-term corticosteroid therapy who presented with symptoms of acute abdomen with minimal low back symptoms. No intraabdominal process was found by abdominal studies and exploratory laparotomy. Increased lower back symptoms led to further skeletal spine studies, which initially demonstrated a compression fracture at the twelfth thoracic (T12) vertebra. Later, a T8 and a fourth lumbar (L4) compression fracture were also found. Her abdominal and lower back symptoms resolved on conservative therapy. Although the rate of these occurrences are unknown, compression spine fractures should be considered in elderly patients presenting with acute abdomen after being on long-term corticosteroid therapy.
Asunto(s)
Fracturas Espontáneas/complicaciones , Obstrucción Intestinal/etiología , Vértebras Lumbares/lesiones , Fracturas de la Columna Vertebral/complicaciones , Vértebras Torácicas/lesiones , Anciano , Femenino , Fracturas Espontáneas/inducido químicamente , Humanos , Lupus Eritematoso Sistémico/tratamiento farmacológico , Prednisona/efectos adversos , Prednisona/uso terapéutico , Fracturas de la Columna Vertebral/inducido químicamente , Factores de TiempoRESUMEN
The authors described a rare case of the middle ear tuberculosis in 4 years old child. It was the mastoiditis, which was operated upon. Two years without recurrency in observation.