Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 70
Filtrar
1.
J Eur Acad Dermatol Venereol ; 38(1): 31-41, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37818828

RESUMEN

Treating atopic dermatitis (AD) in pregnant or breastfeeding women, and in women and men with AD aspiring to be parents is difficult and characterized by uncertainty, as evidence to inform decision-making on systemic anti-inflammatory treatment is limited. This project mapped consensus across dermatologists, obstetricians and patients in Northwestern Europe to build practical advice for managing AD with systemic anti-inflammatory treatment in men and women of reproductive age. Twenty-one individuals (sixteen dermatologists, two obstetricians and three patients) participated in a two-round Delphi process. Full consensus was reached on 32 statements, partial consensus on four statements and no consensus on four statements. Cyclosporine A was the first-choice long-term systemic AD treatment for women preconception, during pregnancy and when breastfeeding, with short-course prednisolone for flare management. No consensus was reached on second-choice systemics preconception or during pregnancy, although during breastfeeding dupilumab and azathioprine were deemed suitable. It may be appropriate to discuss continuing an existing systemic AD medication with a woman if it provides good disease control and its benefits in pregnancy outweigh its risks. Janus kinase (JAK) inhibitors, methotrexate and mycophenolate mofetil should be avoided by women during preconception, pregnancy and breastfeeding, with medication-specific washout periods advised. For men preconception: cyclosporine A, azathioprine, dupilumab and corticosteroids are appropriate; a 3-month washout prior to conception is desirable for methotrexate and mycophenolate mofetil; there was no consensus on JAK inhibitors. Patient and clinician education on appropriate (and inappropriate) AD treatments for use in pregnancy is vital. A shared-care framework for interdisciplinary management of AD patients is advocated and outlined. This consensus provides interdisciplinary clinical guidance to clinicians who care for patients with AD before, during and after pregnancy. While systemic AD medications are used uncommonly in this patient group, considerations in this article may help patients with severe refractory AD.


Asunto(s)
Ciclosporina , Dermatitis Atópica , Embarazo , Masculino , Humanos , Femenino , Ciclosporina/uso terapéutico , Metotrexato/uso terapéutico , Lactancia Materna , Dermatitis Atópica/tratamiento farmacológico , Azatioprina/uso terapéutico , Ácido Micofenólico/uso terapéutico , Consenso , Antiinflamatorios/uso terapéutico
2.
Lipids ; 36(9): 997-1006, 2001 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-11724473

RESUMEN

"Isomeric fatty acids" is a term that refers to the trans- and positional isomers formed during hydrogenation of naturally occurring oils. The purposes of this paper are as follows: (i) to summarize potential exposure of infants to isomeric fatty acids by reviewing estimates of isomeric fatty acids in the maternal diet, in human milk, and in infant formula/infant foods, and (ii) to evaluate the evidence for adverse effects of isomeric fatty acids on infant development with respect to growth and essential fatty acid status. Estimates of the intake of trans-fatty acids vary widely both within and across populations. Current estimates of trans-fatty acids in the North American population are 4-11% of total fatty acids or 3-13 g/(person x d), whereas in Mediterranean countries in which olive oil is the primary fat and in Far Eastern countries in which little commercially hydrogenated fat is consumed, per capita consumption of trans-fatty acids is <1-2 g/d. The trans-fatty acid content of human milk reflects the cross-cultural variation in the maternal diet, with trans-fatty acids in human milk samples ranging from 6 to 7% in North America to <0.5% in Hong Kong. Trans-fatty acids are transferred from the maternal diet through the placenta to the developing fetus or through milk to the breast-fed infant. In some studies, plasma trans-fatty acids are inversely related to birth weight and head circumference. The hypothesis that dietary trans-fatty acids could inhibit biosynthesis of long-chain polyunsaturated fatty acids with 20 and 22 carbon atoms and thus affect infant development is supported by studies demonstrating an inverse correlation of plasma trans-fatty acids with n-3 and n-6 longchain polyunsaturated fatty acids in infants. However, no such relationship has been observed in human milk. A definitive answer concerning a potentially adverse effect of dietary trans-fatty acids on infant development awaits future studies.


Asunto(s)
Ácidos Grasos/química , Ácidos Grasos/fisiología , Estado de Salud , Animales , Dieta , Asia Oriental , Ácidos Grasos/farmacología , Femenino , Crecimiento/efectos de los fármacos , Humanos , Lactante , Isomerismo , Región Mediterránea , Leche Humana/metabolismo , América del Norte
3.
J Neurooncol ; 52(3): 263-72, 2001 May.
Artículo en Inglés | MEDLINE | ID: mdl-11519857

RESUMEN

Glioblastoma multiforme (WHO grade IV; GBM) is the most common primary brain tumor with a median survival of less than one year despite multimodal treatment regimens. However, a small subgroup of GBM patients has a better clinical outcome, with a small number of patients surviving several years. Apoptosis, a genetically determined program of cell suicide, may be induced as a consequence of critical DNA damage. However, due to defects in the signaling pathways, cancer cells may escape apoptosis, despite carrying irreversible DNA damage. In the present study, we have analyzed tumors of two age-matched, equally treated groups of GBM patients with different postoperative time to tumor progression (TTP), defined as 'short-term' for TTP of less than 6 months (n = 54), and 'long-term' for TTP of more than 12 months (n = 39) for alterations in apoptosis regulatory pathways: Mutations of the TP53 tumor suppressor gene and/or nuclear accumulation of its gene product p53, expression of Waf/p21, CD95 (Apo1/Fas), and Bcl-2. TP53 mutations were found in 12 out of 54 (22%) GBMs of short-term survivors and 8 out of 35 (23%) tumors of long-term survivors; the respective numbers for nuclear p53 protein accumulation were 12/53 (23%) and 10/37 (27%). Waf1/p21 expression was found in 13/53 (25%) tumors of short-term survivors and 9/35 (26%) GBMs of long-term survivors. The respective numbers for Bcl-2 expression were 25/42 (60%) and 22/36 (61%) and for CD95 (Apo1/Fas) expression 20/49 (41%) and 14/36 (39%) GBMs. The percentage of alterations in genes/proteins involved in the apoptotic pathway investigated here was virtually identical in the two groups of clinically different GBM patients. Thus, our data imply that none of these alterations investigated per se has a strong impact on the overall survival of GBM patients.


Asunto(s)
Neoplasias Encefálicas/mortalidad , Núcleo Celular/metabolismo , Ciclinas/biosíntesis , Genes p53 , Glioblastoma/mortalidad , Proteínas de Neoplasias/biosíntesis , Proteínas Proto-Oncogénicas c-bcl-2/biosíntesis , Proteína p53 Supresora de Tumor/metabolismo , Receptor fas/biosíntesis , Adulto , Anciano , Apoptosis/genética , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Inhibidor p21 de las Quinasas Dependientes de la Ciclina , Ciclinas/genética , Daño del ADN , ADN de Neoplasias/genética , Femenino , Perfilación de la Expresión Génica , Genes bcl-2 , Glioblastoma/genética , Glioblastoma/metabolismo , Humanos , Pérdida de Heterocigocidad , Masculino , Persona de Mediana Edad , Proteínas de Neoplasias/genética , Polimorfismo Conformacional Retorcido-Simple , Pronóstico , Análisis de Supervivencia , Sobrevivientes , Receptor fas/genética
4.
J Biol Chem ; 276(39): 36460-6, 2001 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-11486005

RESUMEN

The yeast Snf1 kinase and its metazoan orthologues, the AMP-activated protein kinases, are activated in response to nutrient limitation. Activation requires the phosphorylation of a conserved threonine residue in the activation loop of the catalytic subunit. A phosphopeptide antibody was generated that specifically recognizes Snf1 protein that is phosphorylated in its activation loop on threonine 210. Using this reagent, we show that phosphorylation of threonine 210 correlates with Snf1 activity, since it is detected in cells subjected to glucose limitation but not in cells grown in abundant glucose. A Snf1 mutant completely lacking kinase activity was phosphorylated normally on threonine 210 in glucose-starved cells, eliminating the possibility that the threonine 210 modification is due to an autophosphorylation event. Cells lacking the Reg1 protein, a regulatory subunit for the Glc7 phosphatase, showed constitutive phosphorylation of Snf1 threonine 210. Exposure of cells to high concentrations of sodium chloride also induced phosphorylation of Snf1. Interestingly, Mig1, a downstream target of Snf1 kinase, is phosphorylated in glucose-stressed but not sodium-stressed cells. Finally, cells lacking the gamma subunit of the Snf1 kinase complex encoded by the SNF4 gene exhibited normal regulation of threonine 210 phosphorylation in response to glucose limitation but are unable to phosphorylate Mig1 efficiently. Our data indicate that activation of the Snf1 kinase complex involves two steps, one that requires a distinct upstream kinase and one that is mediated by the gamma subunit of the kinase itself.


Asunto(s)
Proteínas Portadoras , Regulación Enzimológica de la Expresión Génica , Regulación Fúngica de la Expresión Génica , Proteínas Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas de Saccharomyces cerevisiae , Treonina/metabolismo , Factores de Transcripción/metabolismo , Proteínas Quinasas Activadas por AMP , Alelos , Western Blotting , Dominio Catalítico , Activación Enzimática , Epítopos/metabolismo , Proteínas Fúngicas/metabolismo , Genotipo , Glucosa/metabolismo , Iones , Modelos Biológicos , Mutación , Fosfoproteínas Fosfatasas/metabolismo , Fosforilación , Fosfotreonina/metabolismo , Mutación Puntual , Pruebas de Precipitina , Unión Proteica , Proteína Fosfatasa 1 , Saccharomyces cerevisiae/enzimología , Transducción de Señal , Sodio/farmacología , Cloruro de Sodio/farmacología
5.
EMBO J ; 19(18): 4936-43, 2000 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-10990457

RESUMEN

The Snf1 kinase and its mammalian homolog, the AMP-activated protein kinase, are heterotrimeric enzymes composed of a catalytic alpha-subunit, a regulatory gamma-subunit and a beta-subunit that mediates heterotrimer formation. Saccharomyces cerevisiae encodes three beta-subunit genes, SIP1, SIP2 and GAL83. Earlier studies suggested that these subunits may not be required for Snf1 kinase function. We show here that complete and precise deletion of all three beta-subunit genes inactivates the Snf1 kinase. The sip1Delta sip2Delta gal83Delta strain is unable to derepress invertase, grows poorly on alternative carbon sources and fails to direct the phosphorylation of the Mig1 and Sip4 proteins in vivo. The SIP1 sip2Delta gal83Delta strain manifests a subset of Snf phenotypes (Raf(+), Gly(-)) observed in the snf1Delta 10 strain (Raf(-), Gly(-)), suggesting that individual beta-subunits direct the Snf1 kinase to a subset of its targets in vivo. Indeed, deletion of individual beta-subunit genes causes distinct differences in the induction and phosphorylation of Sip4, strongly suggesting that the beta-subunits play an important role in substrate definition.


Asunto(s)
Proteínas Serina-Treonina Quinasas/química , Proteínas Serina-Treonina Quinasas/genética , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Proteínas Quinasas Activadas por AMP , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico , Western Blotting , División Celular/genética , Proteínas de Unión al ADN/metabolismo , Epítopos/química , Proteínas Fúngicas/metabolismo , Eliminación de Gen , Prueba de Complementación Genética , Glucosa/farmacología , Glicósido Hidrolasas/metabolismo , Modelos Biológicos , Mutagénesis Sitio-Dirigida , Fenotipo , Fosforilación , Estructura Terciaria de Proteína , Proteínas Represoras/metabolismo , Saccharomyces cerevisiae/enzimología , Transactivadores/metabolismo , beta-Fructofuranosidasa
6.
J Neurol ; 247(6): 455-60, 2000 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-10929275

RESUMEN

The overall prognosis for patients with glioblastoma multiforme is extremely poor. However, a small proportion of patients enjoy prolonged survival. This study investigated retrospectively the extent to which erroneous histopathological classification may contribute to long-term survival of patients initially diagnosed with "glioblastoma multiforme." We compared two age- and gender-matched patient groups with different postoperative time to tumor progression (TTP), defined as "short-term" for TTP of less than 6 months (n = 54), and "long-term" for TTP of more than 12 months (n = 52). Histological specimens of the corresponding tumors, all primarily diagnosed as glioblastoma multiforme, were reevaluated according to the current World Health Organization (WHO) classification of central nervous system tumors, with the investigators being blinded to clinical outcome. Among the tumors from short-term TTP patients, one tumor (2%) was reclassified as anaplastic oligoastrocytoma (WHO grade III) while the remaining 53 were confirmed as glioblastoma multiforme. In contrast, 13 tumors (25%) from the long-term TTP patients were reclassified, mostly as anaplastic oligodendroglioma (WHO grade III; n = 7) or anaplastic oligoastrocytoma (WHO grade III, n = 2), respectively. In addition, three were reclassified as anaplastic astrocytoma (WHO grade III), and one was identified as anaplastic pilocytic astrocytoma (WHO grade III). Our data indicate that a sizable proportion of glioblastoma patients with long-term survival actually carry malignant gliomas with oligodendroglial features. The correct histopathological recognition of these tumors has not only prognostic but also therapeutic implications, since oligodendroglial tumors are more likely to respond favorably to chemotherapy.


Asunto(s)
Neoplasias Encefálicas/mortalidad , Neoplasias Encefálicas/patología , Glioblastoma/mortalidad , Glioblastoma/patología , Adulto , Anciano , Errores Diagnósticos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Variaciones Dependientes del Observador , Estudios Retrospectivos , Tasa de Supervivencia , Factores de Tiempo
7.
J Neuropathol Exp Neurol ; 59(6): 544-58, 2000 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-10850867

RESUMEN

Brain tumors pose a particular challenge to molecular oncology. Many different tumor entities develop in the nervous system and some of them appear to follow distinct pathogenic routes. Molecular genetic alterations have increasingly been reported in nervous system neoplasms. However, a considerable number of affected genes remain to be identified. We present here a comprehensive allelotype analysis of 466 nervous system tumors based on loss of heterozygosity (LOH) studies with 129 microsatellite markers that span the genome. Specific alterations of the EGFR, CDK4, CDKN2A, TP53, DMBT1, NF2, and PTEN genes were analyzed in addition. Our data point to several novel genetic loci associated with brain tumor development, demonstrate relationships between molecular changes and histopathological features, and further expand the concept of molecular tumor variants in neuro-oncology. This catalogue may provide a valuable framework for future studies to delineate molecular pathways in many types of human central nervous system tumors.


Asunto(s)
Alelos , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/patología , Humanos , Pérdida de Heterocigocidad , Repeticiones de Microsatélite , Biología Molecular/métodos , Mutación/genética , Análisis de Supervivencia
8.
Pharm Res ; 17(2): 222-8, 2000 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-10751039

RESUMEN

PURPOSE: To investigate concentration dependent permeabilities and metabolism kinetics of thymotrinan (TP3) versus thymocartin (TP4) in nasal epithelium in vitro. METHODS: Excised bovine nasal mucosa was used as an in vitro model. Permeabilities were studied in a diffusion chamber, metabolism kinetics in a reflection kinetics set-up. Studies were performed at various TP3 and TP4 concentrations. The 3H-mannitol flux was measured to monitor junctional permeability. Potential Ca(2+)-complexation was investigated using a Ca(2+)-selective electrode. RESULTS: Permeability of TP3 was negligible at 0.1 and 0.2 mM and increased drastically above 0.4 mM up to -2 X 10(-5) cm s(-1). In the presence of 2 mM TP4 the TP3 permeabilites were significantly above (approximately 4 x 10(-5) cm s(-1)) the level of TP3 without TP4, and TP3 metabolism was totally inhibited. TP3 and TP4 showed a significant concentration dependent effect on the permeability of 3H-mannitol. A hyperosmolarity effect of the peptide solutions was excluded. Transepithelial electrical resistance (TEER; approximately 30 ohms cm2) was unchanged by either TP3 or TP4. At 1 mM TP3 the mucosal-to-serosal permeability was four times higher than serosal-to-mucosal, indicating enzyme polarization. In reflection kinetics studies, TP3 degradation was slightly higher on the mucosal than on the serosal side. TP3 and TP4 followed the same non-linear metabolism kinetics. CONCLUSIONS: Increase in permeability at high TP concentrations involves competitive enzyme saturation combined with self-enhanced paracellular permeation.


Asunto(s)
Adyuvantes Inmunológicos/farmacocinética , Células Epiteliales/enzimología , Mucosa Nasal/citología , Oligopéptidos/farmacocinética , Fragmentos de Péptidos/farmacocinética , Timopoyetinas/farmacocinética , Aminopeptidasas/metabolismo , Animales , Unión Competitiva , Calcio/farmacocinética , Bovinos , Permeabilidad de la Membrana Celular/efectos de los fármacos , Impedancia Eléctrica , Metabolismo Energético/efectos de los fármacos , Técnicas In Vitro , Manitol/farmacocinética , Mucosa Nasal/enzimología , Especificidad por Sustrato , Tritio
9.
J Pharm Sci ; 89(3): 396-407, 2000 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10707019

RESUMEN

The present work aims at the validation of excised bovine nasal mucosa as an in vitro model to address transport and metabolism pathways relative to the nasal mucosal uptake of therapeutic peptides. Preservation of the viability of the excised tissue in the course of in vitro studies of up to 3 h was demonstrated by (i) positive viability staining, (ii) constant transepithelial electrical resistance (42 +/- 12 Omega cm(2)), (iii) constant rates of metabolic turnover, and (iv) linear permeation profiles of therapeutic peptides and (3)H-mannitol. Using 1-leucine-4-methoxy-2-naphthylamide as a model substrate, we observed no difference between bovine and human nasal aminopeptidase activity. By a series of therapeutic peptides, no direct correlation was found between their effective permeability coefficients (from 0. 1 x 10(-5) to 5 x 10(-5) cm s(-1)) and their respective molecular masses (from 417 to 3,432 Da), indicating that other factors dominate nasal permeability. For instance, the permeabilities of metabolically labile peptides were concentration dependent and saturable, as demonstrated for two short thymopoietin fragments, Arg-Lys-Asp (TP3) and Arg-Lys-Asp-Val (TP4). By permeation studies using gonadorelin and two gonadorelin derivatives, buserelin and Hoe 013, without and in the presence of the chemical enhancer bacitracin, we also verified the ability of the model to assess chemical enhancer effects and their reversibility. In conclusion, our work demonstrates the potential of the investigated in vitro model, excised bovine nasal mucosa, to explore mechanistic aspects of nasal transport and metabolism of therapeutic peptides.


Asunto(s)
Mucosa Nasal/metabolismo , Preparaciones Farmacéuticas/metabolismo , Absorción , Aminopeptidasas/metabolismo , Animales , Transporte Biológico Activo , Calcitonina/metabolismo , Bovinos , Permeabilidad de la Membrana Celular/efectos de los fármacos , Electrofisiología , Excipientes , Inmunohistoquímica , Técnicas In Vitro , Linfocitos/metabolismo , Modelos Biológicos , Reproducibilidad de los Resultados , Timopoyetinas/metabolismo
10.
J Muscle Res Cell Motil ; 21(6): 577-86, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-11206135

RESUMEN

p0071 is a member of the armadillo gene family that is expressed in a wide variety of mammalian tissues and cell types with a prominent cell-cell contact association in epithelial cells. Here, we report the expression and localization patterns of p0071 in differentiating human skeletal muscle cells and in normal and diseased human skeletal muscle tissues. Northern blots revealed expression of p0071 mRNA in adult skeletal muscle tissue. RT-PCR analysis and Western blotting experiments identified two differentially spliced isoforms of p0071. The balance between these isoforms shifted during in vitro differentiation of isolated muscle cells from predominant expression of the short variant to a preponderance of the larger variant from day 6 onwards. Immunolocalization studies in mature skeletal muscle tissue revealed that p0071 is a constituent of myofibrils with a distinct localization at the level of sarcomeric N2-lines. During myofibrillogenesis, p0071 was not detected in non-striated nascent myofibrils, but became apparent shortly after the development of compact Z-discs in early myotubes. Furthermore, we studied the expression of p0071 in a wide variety of neuromuscular disorders by indirect immunofluorescence. Here, the myofibrillar staining of p0071 was preserved in all the disease entities included in our study. Our results provide the first evidence that a member of the armadillo multigene family is a constituent of the contractile apparatus in human skeletal muscle. The localization of p0071 at the level of I-bands and the timepoint of its integration into developing myofibrils suggest a possible role in the organization of thin filaments.


Asunto(s)
Proteínas del Citoesqueleto/genética , Proteínas del Citoesqueleto/metabolismo , Proteínas de Drosophila , Proteínas de Insectos/metabolismo , Desarrollo de Músculos , Músculo Esquelético/crecimiento & desarrollo , Músculo Esquelético/metabolismo , Sarcómeros/metabolismo , Transactivadores , Factores de Edad , Proteínas del Dominio Armadillo , Diferenciación Celular/fisiología , Células Cultivadas , Regulación del Desarrollo de la Expresión Génica/fisiología , Humanos , Proteínas de Insectos/clasificación , Proteínas de Insectos/genética , Contracción Muscular/fisiología , Músculo Esquelético/ultraestructura , Enfermedades Neuromusculares/metabolismo , Enfermedades Neuromusculares/patología , Enfermedades Neuromusculares/fisiopatología , Placofilinas , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , ARN Mensajero/metabolismo , Sarcómeros/ultraestructura , Transducción de Señal/fisiología
12.
J Pathol ; 188(2): 168-73, 1999 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-10398160

RESUMEN

The MEN1 gene on chromosome 11q13 is mutated in patients afflicted with multiple endocrine neoplasia syndrome type 1 (MEN1). These patients develop endocrine tumours of the pancreas, the parathyroid, and the anterior pituitary. In order to determine the role of MEN1 in sporadic pituitary adenomas, 61 pituitary adenomas were analysed from patients without evidence of a familial tumour syndrome. Single strand conformation polymorphism (SSCP) analysis was performed for the entire coding sequence of MEN1. Fragments with aberrant migration patterns were sequenced bidirectionally. Only a single somatic mutation was detected in this series. In addition, several previously reported and three novel polymorphisms were observed. Loss of heterozygosity analysis with 12 polymorphic markers, however, identified 13 pituitary adenomas with allelic deletions on chromosome 11. Allelic losses occurred significantly more often in pituitary adenomas with hormone secretion than in non-functioning adenomas. These data suggest that MEN1 mutations are rare events in sporadic pituitary adenomas. However, the discrepancy of only 1/61 adenomas with MEN1 mutation but 13/61 (22 per cent) with allelic loss on chromosome 11 may suggest the presence of a yet unknown tumour suppressor gene, relevant to the pathogenesis of sporadic pituitary adenomas.


Asunto(s)
Adenoma/genética , Neoplasia Endocrina Múltiple/genética , Neoplasias Hipofisarias/genética , Cromosomas Humanos Par 11 , Cartilla de ADN , Eliminación de Gen , Humanos , Pérdida de Heterocigocidad , Mutación , Polimorfismo Genético , Polimorfismo Conformacional Retorcido-Simple , Análisis de Secuencia de ADN
13.
Mol Cell Biol ; 19(7): 4561-71, 1999 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10373505

RESUMEN

The Std1 protein modulates the expression of glucose-regulated genes, but its exact molecular role in this process is unclear. A two-hybrid screen for Std1-interacting proteins identified the hydrophilic C-terminal domains of the glucose sensors, Snf3 and Rgt2. The homologue of Std1, Mth1, behaves differently from Std1 in this assay by interacting with Snf3 but not Rgt2. Genetic interactions between STD1, MTH1, SNF3, and RGT2 suggest that the glucose signaling is mediated, at least in part, through interactions of the products of these four genes. Mutations in MTH1 can suppress the raffinose growth defect of a snf3 mutant as well as the glucose fermentation defect present in cells lacking both glucose sensors (snf3 rgt2). Genetic suppression by mutations in MTH1 is likely to be due to the increased and unregulated expression of hexose transporter genes. In media lacking glucose or with low levels of glucose, the hexose transporter genes are subject to repression by a mechanism that requires the Std1 and Mth1 proteins. An additional mechanism for glucose sensing must exist since a strain lacking all four genes (snf3 rgt2 std1 mth1) is still able to regulate SUC2 gene expression in response to changes in glucose concentration. Finally, studies with green fluorescent protein fusions indicate that Std1 is localized to the cell periphery and the cell nucleus, supporting the idea that it may transduce signals from the plasma membrane to the nucleus.


Asunto(s)
Proteínas Fúngicas/metabolismo , Regulación Fúngica de la Expresión Génica , Glucosa/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas de Transporte de Monosacáridos/metabolismo , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Proteínas Adaptadoras Transductoras de Señales , Clonación Molecular , Proteínas Fúngicas/genética , Regulación Enzimológica de la Expresión Génica , Proteínas Facilitadoras del Transporte de la Glucosa , Glicósido Hidrolasas/genética , Glicósido Hidrolasas/metabolismo , Proteínas Fluorescentes Verdes , Péptidos y Proteínas de Señalización Intracelular , Proteínas Luminiscentes/metabolismo , Proteínas de la Membrana/genética , Proteínas de Transporte de Monosacáridos/genética , Mutagénesis , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Saccharomyces cerevisiae/metabolismo , beta-Fructofuranosidasa
14.
J Neuropathol Exp Neurol ; 58(1): 40-5, 1999 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-10068312

RESUMEN

Over the last years, distinct genetic lesions have been associated with individual tumor entities. Stereotactic biopsy has become an essential diagnostic tool in surgical neuro-oncology. In order to evaluate the potential of molecular analyses in stereotactic biopsies, we examined a series of 156 human brain tumors from patients undergoing stereotactic biopsy for molecular alterations typically seen in astrocytic gliomas and compared those results with a control group of 268 astrocytic tumors obtained at open surgery. Stereotactic biopsies of astrocytomas with borderline histopathological features between the WHO grades II and III showed a higher rate of allelic losses on chromosome 10 than those of the WHO grade II from open surgery (p = 0.011). Stereotactic biopsies of astrocytomas with borderline histopathological features between the WHO grades III and IV showed a higher rate of allelic losses on chromosome 10 than those of the WHO grade III from open surgery (p = 0.013). This indicates that stereotactic biopsies with features intermediate between grades are likely to correspond to the higher malignancy grade. Our data demonstrate that molecular genetic approaches can be successfully applied to stereotactic glioma biopsies. The difference in the distribution of malignancy associated genetic alterations between a stereotactic and openly resected group of gliomas indicates that histopathology may underestimate the malignant potential in some stereotactic specimens. We propose to further evaluate the molecular analysis of stereotactic glioma biopsies as a useful adjunct to standard histopathological procedures.


Asunto(s)
Neoplasias Encefálicas/patología , Glioma/patología , Pérdida de Heterocigocidad , Manejo de Especímenes/métodos , Biopsia , Neoplasias Encefálicas/clasificación , Cromosomas Humanos Par 10 , Cromosomas Humanos Par 17 , Cromosomas Humanos Par 19 , Receptores ErbB/genética , Estudios de Evaluación como Asunto , Eliminación de Gen , Glioma/clasificación , Humanos , Técnicas Estereotáxicas
15.
Biochemistry ; 37(47): 16582-90, 1998 Nov 24.
Artículo en Inglés | MEDLINE | ID: mdl-9843425

RESUMEN

We studied the mechanisms involved in the translocation of human calcitonin (hCT) through excised bovine nasal mucosa (net mucosal-to-serosal permeability approximately 10(-)5 cm s-1). To determine structural requirements for the suggested vesicular internalization two carboxyfluorescein-labeled (fl) hCT fragments, the C-terminal fragment [Nalpha-fl]hCT(9-32) and the N-terminal fragment [Lys(fl)18]hCT(1-24) were synthesized. In presence of the endocytosis inhibitor cytochalasin D mucosal-to-serosal and serosal-to-mucosal hCT permeabilities were equal. Pathway visualization by confocal laser scanning microscopy showed punctated fluorescence indicating vesicular internalization of both hCT and [Nalpha-fl]hCT(9-32). In contrast, the N-terminal fragment lacking the beta-sheet forming C-terminus (25-32) was not internalized. Circular dichroism showed that, when interacting with neutral and negatively charged liposomes, hCT adopts beta-sheet conformation. In a concentrated aqueous solution, beta-sheet formation induces hCT self-assembly and fibrillation. High partitioning of hCT into lipid bilayer membranes was reflected by an apparent partition coefficient log D(pH 7.4) = 2.5 (liposome-buffer equilibrium dialysis). We propose that the high lipid partitioning and beta-sheet formation result in C-terminus-restricted supramolecular self-assembly of hCT and [Nalpha-fl]hCT(9-32) in lipid membranes. Vesicular internalization is suggested to be associated with self-assembly induced perturbation of the lipid bilayer. Condensed hCT self-assemblies may explain the high capacity of net mucosal-to-serosal hCT permeation, which compares favorably with the low transport capacity of receptor-mediated endocytosis.


Asunto(s)
Calcitonina/metabolismo , Lípidos de la Membrana/metabolismo , Mucosa Nasal/metabolismo , 1,2-Dipalmitoilfosfatidilcolina/metabolismo , Secuencia de Aminoácidos , Animales , Transporte Biológico , Calcitonina/química , Bovinos , Permeabilidad de la Membrana Celular , Dicroismo Circular , Epitelio/metabolismo , Humanos , Liposomas/metabolismo , Microscopía Confocal , Datos de Secuencia Molecular , Fosfatidilgliceroles/metabolismo , Estructura Secundaria de Proteína
16.
Genetics ; 150(1): 31-42, 1998 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-9725828

RESUMEN

The calcium-dependent protein phosphatase calcineurin plays an essential role in ion homeostasis in yeast. In this study, we identify a parallel ion stress response pathway that is independent of the calcineurin signaling pathway. Cells with null alleles in both STD1 and its homologue, MTH1, manifest numerous phenotypes observed in calcineurin mutants, including sodium, lithium, manganese, and hydroxyl ion sensitivity, as well as alpha factor toxicity. Furthermore, increased gene dosage of STD1 suppresses the ion stress phenotypes in calcineurin mutants and confers halotolerance in wild-type cells. However, Std1p functions in a calcineurin-independent ion stress response pathway, since a std1 mth1 mutant is FK506 sensitive under conditions of ion stress. Mutations in other genes known to regulate gene expression in response to changes in glucose concentration, including SNF3, RGT2, and SNF5, also affect cell growth under ion stress conditions. Gene expression studies indicate that the regulation of HAL1 and PMR2 expression is affected by STD1 gene dosage. Taken together, our data demonstrate that response to ion stress requires the participation of both calcineurin-dependent and -independent pathways.


Asunto(s)
Calcineurina/metabolismo , Estrés Oxidativo , Saccharomyces cerevisiae/metabolismo , Sodio/metabolismo , Adaptación Fisiológica/genética , Secuencia de Bases , Cartilla de ADN , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Dosificación de Gen , Regulación Fúngica de la Expresión Génica , Glucosa/metabolismo , Homeostasis , Mutación , Fenotipo , Saccharomyces cerevisiae/fisiología , Transducción de Señal
17.
Gene ; 215(1): 131-41, 1998 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-9666103

RESUMEN

The STD1 gene of Saccharomyces cerevisiae was isolated independently as a multicopy suppressor of a dominant negative mutation in the TATA-binding protein and of a mutation in the Snf1/Snf4 kinase complex, suggesting that Std1 might couple the Snf1 kinase signaling pathway to the transcriptional machinery. In order to identify the protein domains that specify these activities of the Std1 protein, a plasmid library of randomly mutagenized STD1 genes was screened for loss of function alleles using complementation of the raffinose growth defect of a std1-, mth1- strain as an assay. One missense allele (P236S) with complete loss of function at 30 degreesC and four missense alleles (L173F, E225K, S269L and E274K) that conferred a temperature sensitive phenotype were identified. The C-terminal 20 residues of Std1 were essential for SUC2 derepression, whereas the deletion of the N-terminal 96 residues did not affect SUC2 gene induction. Std1 mutants that lost the ability to induce SUC2, were also unable to suppress the growth defect caused by the expression of the dominant negative TBPDelta57 protein, suggesting that these two genetic screens may be detecting the same biological activity.


Asunto(s)
Aminoácidos/fisiología , Proteínas Portadoras/genética , Proteínas de Unión al ADN/genética , Proteínas Fúngicas/fisiología , Proteínas de Transporte de Membrana , Proteínas de Plantas/genética , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Factores de Transcripción/genética , Alelos , Aminoácidos/química , Aminoácidos/genética , Proteínas Portadoras/metabolismo , Clonación Molecular , ADN de Hongos/análisis , ADN de Hongos/genética , ADN de Hongos/aislamiento & purificación , Proteínas de Unión al ADN/metabolismo , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Eliminación de Gen , Regulación Fúngica de la Expresión Génica , Biblioteca de Genes , Genes Fúngicos/genética , Genes Supresores/genética , Genes Supresores/fisiología , Péptidos y Proteínas de Señalización Intracelular , Mutagénesis Sitio-Dirigida , Mutación/genética , Proteínas de Plantas/metabolismo , Polimorfismo Conformacional Retorcido-Simple , Saccharomyces cerevisiae/crecimiento & desarrollo , Saccharomyces cerevisiae/fisiología , Análisis de Secuencia de ADN , Supresión Genética/genética , Proteína de Unión a TATA-Box , Temperatura , Factores de Transcripción/metabolismo , Transcripción Genética/genética , Activación Transcripcional/genética
18.
J Biol Chem ; 273(26): 16082-9, 1998 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-9632660

RESUMEN

A large number of plasmids have been shown to replicate by a rolling circle (RC) mechanism. The initiators encoded by these plasmids have origin-specific, nicking-closing activity that is required for the initiation and termination of RC replication. Since the initiators of many RC plasmids are rate-limiting for replication, these proteins are usually inactivated after supporting one round of replication. In the case of the pT181 plasmid, inactivation of the initiator RepC protein occurs by the attachment of an oligonucleotide to its active tyrosine residue. We have generated the inactivated form of RepC, termed RepC*, in vitro and investigated the effects of attachment of the oligonucleotide on its various biochemical activities. Our results demonstrate that while RepC* is inactive in nicking-closing and replication activities due to the blockage of its active tyrosine residue, it is competent in origin DNA binding and DNA religation activities. We have investigated the oligomeric state of RepC and RepC* and found that RepC exists as a dimer in solution and can oligomerize on the DNA. We have generated heterodimers in vitro between the wild-type and epitope-tagged RepC proteins. In electrophoretic mobility shift experiments, the initiator heterodimers generated a novel DNA-protein complex, demonstrating that it binds to DNA as a dimer. We have shown that a DNA binding mutant of RepC can be targeted to the origin in the presence of the wild-type protein primarily through a protein-protein interaction. Interestingly, RepC* is defective in its ability to oligomerize on the DNA. RepC* inhibited the DNA binding and replication activity of wild-type RepC to only a very limited extent, suggesting that it may play only a minor regulatory role in replication in vivo. Based on these and earlier results, we propose a model for the role of RepC during the initiation and termination of pT181 RC replication.


Asunto(s)
Proteínas Bacterianas/metabolismo , Replicación del ADN , Proteínas de Unión al ADN/metabolismo , Oligonucleótidos/farmacología , Origen de Réplica/efectos de los fármacos , Secuencia de Bases , Centrifugación por Gradiente de Densidad , ADN Bacteriano/metabolismo , Dimerización , Datos de Secuencia Molecular , Conformación de Ácido Nucleico , Plásmidos/metabolismo , Tirosina/metabolismo
19.
Z Kardiol ; 87(3): 218-26, 1998 Mar.
Artículo en Alemán | MEDLINE | ID: mdl-9586157

RESUMEN

Imaging of cardiac masses is technically highly demanding. Imaging techniques should fulfill the following requirements: excellent spatial and temporal resolution, short imaging time, broad availability, low cost. Diagnostic questions include: tumor origin, size, extension, tissue type, functional consequences of tumor involvement. Transthoracic echocardiography is the imaging technique of choice in most patients. If clinical questions remain, TEE, CT or MRI can be used as secondary imaging techniques. Advantages of MRI include: excellent spatial and temporal resolution, multiplanar capabilities, large field of view, lack of radiation. Pericardial and intracardiac as well as paracardiac masses are depicted in great detail and therapeutically relevant information is usually obtained in addition to what is known from echocardiography. Although tissue differentiation is possible, a histologic diagnosis cannot be obtained. Disadvantages of MRI are artifacts in patients with severe arrhythmias or dyspnoea.


Asunto(s)
Neoplasias Cardíacas/diagnóstico , Imagen por Resonancia Magnética , Neoplasias Cardíacas/secundario , Humanos , Miocardio/patología , Pericardio/patología , Sensibilidad y Especificidad
20.
Peptides ; 19(3): 599-607, 1998.
Artículo en Inglés | MEDLINE | ID: mdl-9533651

RESUMEN

In vitro permeation of human calcitonin (hCT), salmon calcitonin (sCT), and the somatostatin analog octreotide (SMS) through excised bovine nasal mucosa was studied applying donor/receiver experiments and confocal laser scanning microscopy. Permeabilities of gonadorelin, buserelin, Hoe013, and of thymopoietin fragments TP5 and TP4 were also included. Apparent permeability coefficients (Peff) ranged between 4 x 10(-5) (SMS) and 1.7 x 10(-5) cm s(-1) (TP4). Such Peff are typical for leaky-type airway epithelia. The order of permeabilities was: SMS >> hCT, sCT > buserelin, Hoe013 >> TP5 > TP4, LHRH. The relatively high permeability of hCT and sCT contrasted to their high molecular weight. At 37 degrees C, the permeability of hCT from mucosal to serosal (m-to-s) was found two-fold higher (p < 0.05) than from serosal to mucosal (s-to-m). Controls using 3H-mannitol showed equal permeabilities in both directions. At 4 degrees C, permeation of hCT was reduced but equal in both directions (m-to-s and s-to-m). As evaluated by confocal laser scanning microscopy, uptake studies with FITC-18-hCT revealed intracellular fluorescence in the epithelial cells, at 10 min/10 microM exposure in the form of fluorescent vesicles. By combination of these findings, an endocytotic pathway is suggested to contribute to the transport of hCT through nasal epithelium.


Asunto(s)
Calcitonina/metabolismo , Mucosa Nasal/metabolismo , Péptidos/metabolismo , Animales , Transporte Biológico , Bovinos , Colorantes Fluorescentes , Humanos , Técnicas In Vitro , Cinética , Microscopía Fluorescente , Permeabilidad , Temperatura
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...