Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 293
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
2.
Heredity (Edinb) ; 116(1): 75-83, 2016 01.
Artigo em Inglês | MEDLINE | ID: mdl-26264548

RESUMO

A significant feature of the genomes of Lepidoptera, butterflies and moths, is the high conservation of chromosome organization. Recent remarkable progress in genome sequencing of Lepidoptera has revealed that syntenic gene order is extensively conserved across phylogenetically distant species. The ancestral karyotype of Lepidoptera is thought to be n=31; however, that of the most well-studied moth, Bombyx mori, is n=28, and diverse studies suggest that three chromosomal fusion events occurred in this lineage. To identify the boundaries between predicted ancient fusions involving B. mori chromosomes 11, 23 and 24, we constructed fluorescence in situ hybridization (FISH)-based chromosome maps of the European corn borer, Ostrinia nubilalis (n=31). We first determined a 511 Mb genomic sequence of the Asian corn borer, O. furnacalis, a congener of O. nubilalis, and isolated bacterial artificial chromosomes and fosmid clones that were expected to localize in candidate regions for the boundaries using these sequences. Combined with FISH and genetic analysis, we narrowed down the candidate regions to 40 kb-1.5 Mb, in strong agreement with a previous estimate based on the genome of a butterfly, Melitaea cinxia. The significant difference in the lengths of the candidate regions where no functional genes were observed may reflect the evolutionary time after fusion events.


Assuntos
Evolução Biológica , Mapeamento Cromossômico , Genoma de Inseto , Mariposas/genética , Sintenia , Animais , Cromossomos Artificiais Bacterianos , Genes de Insetos , Genótipo , Hibridização in Situ Fluorescente , Masculino , Telômero/genética , Zea mays
3.
J Obstet Gynaecol ; 36(4): 479-82, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26471310

RESUMO

Pregnant women tend to fall and increased body postural instability, namely body sway, may be one of the causative factors. We had a clinical impression that pregnant women after long-term bed rest tend to fall. We hypothesised that such women may show increased body sway, which we attempted to determine. Pregnant women (n = 161) were divided into three groups: (i) women with preterm labour after 2-week bed rest, (ii) those after 4-week bed rest, and (iii) those without bed rest or preterm labour. Body sway was analysed using stabilometry, that is, computed analysis of movement of the centre of gravity. The 3 groups fundamentally showed the same stabilometric measurements. Women with oedema showed greater medial-lateral sway than those without it. Factors other than oedema yielded no differences in stabilometric parameters. Long-term bed rest fundamentally did not increase body sway to the extent that stabilometry could reveal it. It may be prudent to consider that pregnant women with oedema tend to fall.


Assuntos
Acidentes por Quedas , Repouso em Cama/efeitos adversos , Movimento , Equilíbrio Postural , Complicações na Gravidez/fisiopatologia , Adulto , Edema/complicações , Edema/fisiopatologia , Feminino , Humanos , Postura , Gravidez , Complicações na Gravidez/etiologia
4.
Nat Commun ; 15(1): 6205, 2024 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-39080257

RESUMO

Asteroids smaller than 10 km are thought to be rubble piles formed from the reaccumulation of fragments produced in the catastrophic disruption of parent bodies. Ground-based observations reveal that some of these asteroids are today binary systems, in which a smaller secondary orbits a larger primary asteroid. However, how these asteroids became binary systems remains unclear. Here, we report the analysis of boulders on the surface of the stony asteroid (65803) Didymos and its moonlet, Dimorphos, from data collected by the NASA DART mission. The size-frequency distribution of boulders larger than 5 m on Dimorphos and larger than 22.8 m on Didymos confirms that both asteroids are piles of fragments produced in the catastrophic disruption of their progenitors. Dimorphos boulders smaller than 5 m have size best-fit by a Weibull distribution, which we attribute to a multi-phase fragmentation process either occurring during coalescence or during surface evolution. The density per km2 of Dimorphos boulders ≥1 m is 2.3x with respect to the one obtained for (101955) Bennu, while it is 3.0x with respect to (162173) Ryugu. Such values increase once Dimorphos boulders ≥5 m are compared with Bennu (3.5x), Ryugu (3.9x) and (25143) Itokawa (5.1x). This is of interest in the context of asteroid studies because it means that contrarily to the single bodies visited so far, binary systems might be affected by subsequential fragmentation processes that largely increase their block density per km2. Direct comparison between the surface distribution and shapes of the boulders on Didymos and Dimorphos suggest that the latter inherited its material from the former. This finding supports the hypothesis that some asteroid binary systems form through the spin up and mass shedding of a fraction of the primary asteroid.

5.
Nat Commun ; 15(1): 6206, 2024 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-39080275

RESUMO

Spacecraft observations revealed that rocks on carbonaceous asteroids, which constitute the most numerous class by composition, can develop millimeter-to-meter-scale fractures due to thermal stresses. However, signatures of this process on the second-most populous group of asteroids, the S-complex, have been poorly constrained. Here, we report observations of boulders' fractures on Dimorphos, which is the moonlet of the S-complex asteroid (65803) Didymos, the target of NASA's Double Asteroid Redirection Test (DART) planetary defense mission. We show that the size-frequency distribution and orientation of the mapped fractures are consistent with formation through thermal fatigue. The fractures' preferential orientation supports that these have originated in situ on Dimorphos boulders and not on Didymos boulders later transferred to Dimorphos. Based on our model of the fracture propagation, we propose that thermal fatigue on rocks exposed on the surface of S-type asteroids can form shallow, horizontally propagating fractures in much shorter timescales (100 kyr) than in the direction normal to the boulder surface (order of Myrs). The presence of boulder fields affected by thermal fracturing on near-Earth asteroid surfaces may contribute to an enhancement in the ejected mass and momentum from kinetic impactors when deflecting asteroids.

6.
Br J Cancer ; 109(2): 472-81, 2013 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-23799843

RESUMO

BACKGROUND: The polypeptide N-acetylgalactosaminyltransferases (GalNAc-Ts) family of enzymes regulates the initial steps of mucin-type O-glycosylation. N-acetylgalactosaminyltransferases might show novel patterns of GalNAc-T glycosylation on tumour-derived proteins, which could influence cancer biology, but its mechanisms are unclear. We investigated the association of GalNAc-T3 and -T6 expressions with clinicopathological features and prognoses of patients with renal cell carcinomas (RCCs). METHODS: Expressions of GalNAc-T3/6 and cell-adhesion molecules were analysed immunohistochemically in 254 paraffin-embedded tumour samples of patients with RCC. RESULTS: Of 138 GalNAc-T3+ cases, 46 revealed significant co-expression with GalNAc-T6. N-acetylgalactosaminyltransferases-3+ expression showed a close relationship to poor clinical performance and large tumour size, or pathologically high Fuhrman's grading, and presence of vascular invasion and necrosis. The GalNAc-T3-positivity potentially suppressed adhesive effects with a significantly low ß-catenin expression. Univariate and multivariate analyses showed the GalNAc-T3+ group, but not the GalNAc-T6+ group, to have significantly worse survival rates. CONCLUSION: N-acetylgalactosaminyltransferases-3 expression independently predicts high-grade tumour and poor prognosis in patients with RCC, and may offer a therapeutic target against RCC.


Assuntos
Biomarcadores Tumorais/metabolismo , Carcinoma de Células Renais/patologia , Neoplasias Renais/patologia , N-Acetilgalactosaminiltransferases/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/genética , Carcinoma de Células Renais/enzimologia , Linhagem Celular Tumoral , Estudos de Coortes , Feminino , Humanos , Neoplasias Renais/enzimologia , Masculino , Pessoa de Meia-Idade , N-Acetilgalactosaminiltransferases/genética , Gradação de Tumores , Prognóstico , Estudos Retrospectivos , Polipeptídeo N-Acetilgalactosaminiltransferase
7.
Nat Genet ; 18(2): 111-7, 1998 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9462738

RESUMO

To elucidate the molecular mechanisms whereby expanded polyglutamine stretches elicit a gain of toxic function, we expressed full-length and truncated DRPLA (dentatorubral-pallidoluysian atrophy) cDNAs with or without expanded CAG repeats in COS-7 cells. We found that truncated DRPLA proteins containing an expanded polyglutamine stretch form filamentous peri- and intranuclear aggregates and undergo apoptosis. The apoptotic cell death was partially suppressed by the transglutaminase inhibitors cystamine and monodansyl cadaverine (but not putrescine), suggesting involvement of a transglutaminase reaction and providing a potential basis for the development of therapeutic measures for CAG-repeat expansion diseases.


Assuntos
Apoptose , Proteínas do Tecido Nervoso/biossíntese , Proteínas do Tecido Nervoso/genética , Transglutaminases/antagonistas & inibidores , Repetições de Trinucleotídeos , Animais , Apoptose/efeitos dos fármacos , Sequência de Bases , Células COS , Cadaverina/análogos & derivados , Cadaverina/farmacologia , Cistamina/farmacologia , Primers do DNA , Inibidores Enzimáticos/farmacologia , Humanos , Dados de Sequência Molecular , Doenças Neurodegenerativas/genética , Putrescina/farmacologia , Proteínas Recombinantes/biossíntese , Transfecção
8.
PLoS One ; 18(1): e0273823, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36706103

RESUMO

Anaphes (Anaphes) flavipes (Foerster), a fairyfly (Hymenoptera: Mymaridae) native of Europe, is an economically important egg parasitoid for the natural control of Oulema spp. leaf beetle (Coleoptera: Chrysomelidae) pests of cereal crops such as barley, oats, rye, and wheat in Europe, and for the classical biological control of the invasive Oulema melanopus (L.) in North America. A morphologically very similar Anaphes (Anaphes) nipponicus Kuwayama, known from mainland China, Japan, Republic of Korea, Far East of Russia and Taiwan, is an egg parasitoid of Oulema oryzae (Kuwayama), a pest of rice mainly in temperate parts of East Asia. The nuclear 28S-D2 and ITS2 and the mitochondrial COI genes were used as markers to compare specimens of A. (Anaphes) flavipes reared from eggs of an Oulema sp. on barley in Germany with those of A. (Anaphes) nipponicus reared from eggs of O. oryzae on rice in Honshu Island, Japan. Because the resulting sequences are practically identical, within an expected intraspecific genetic variability, conspecificity of these two nominal species has been confirmed, and consequently A. (Anaphes) nipponicus Kuwayama, 1932, syn. n. is synonymized with A. (Anaphes) flavipes (Foerster, 1841). Taxonomic notes and illustrations are provided for the specimens of both sexes of A. (Anaphes) flavipes from Japan to facilitate their recognition.


Assuntos
Besouros , Hordeum , Himenópteros , Oryza , Animais , Feminino , Masculino , Besouros/genética , Grão Comestível , Europa (Continente) , Ásia Oriental , Avena
9.
Br J Cancer ; 104(12): 1882-9, 2011 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-21587259

RESUMO

BACKGROUND: The family of polypeptide N-acetylgalactosaminyltransferases (GalNAc-Ts) is responsible for the altered glycosylation in cancer. The purpose of our study was to investigate the clinical significance of two isoforms, GalNAc-T6 and -T3, and their correlation with the prognosis of pancreatic cancer. METHODS: Immunohistochemistry was used to analyse GalNAc-T6 and -T3 expressions in 70 clinicopathologically characterised pancreatic cancer cases. RESULTS: Positive expressions of GalNAc-T6 and -T3 were immunohistochemically identified in 51% (36 of 70) and in 77% (54 of 70) of patients, respectively. A close relationship was noted between GalNAc-T6 positive expression and pathological well/moderate differentiated type (P=0.001), small tumour size (P=0.044), absence of vascular invasion (P=0.009), and low stage of the American Joint Committee on Cancer systems (P=0.043). The expression of GalNAc-T3 significantly correlated with good differentiation (P=0.001), but not with other clinicopathologic features. Furthermore, univariate and multivariate analyses revealed that GalNAc-T6 expression was an independent prognosis indicator for the disease, whereas GalNAc-T3 expression had no impact on clinical outcome, even though 33 of 36 GalNAc-T6-positive cases also had a positive expression of GalNAc-T3 (P=0.001, r=0.356). CONCLUSION: Both GalNAc-T6 and -T3 expressions correlated significantly with tumour differentiation, whereas only GalNAc-T6 expression predicted prognosis in pancreatic cancer.


Assuntos
N-Acetilgalactosaminiltransferases/análise , Neoplasias Pancreáticas/mortalidade , Adulto , Idoso , Linhagem Celular Tumoral , Feminino , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Neoplasias Pancreáticas/enzimologia , Neoplasias Pancreáticas/patologia , Prognóstico , Polipeptídeo N-Acetilgalactosaminiltransferase
10.
Acta Paediatr ; 99(7): 1102-4, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20219036

RESUMO

UNLABELLED: A 4-month-old boy was diagnosed with Kawasaki disease. The ordinary treatments with intravenous gammaglobulin and metylpredonisolone were not effective. Infliximab (5 mg/kg) was administrated on 13th day of illness which led to defeverscence and improvement of clinical manifestations. On 23 days of illness, however, desquamative papules and plaques developed on both the extensor surfaces of the forearms and legs. In addition, typical subungual desquamations of fingers and toes followed crusted hyperkeratosis which resembled supprative acrodermatitis. Skin biopsy from the forearm showed inflammatory dyskeratosis with marked hyperkeratosis, epithelial parakeratotsis, loss of granular layer and dominant infiltration of CD8 + T-cells. Local treatment of steroid followed improvement of skin lesions within a few weeks. CONCLUSION: Although previous reports described the beneficial effects of infliximab in patients with Kawasaki disease, it is possible that the administration of infliximab modify psoriasiform skin lesion associated with Kawasaki disease.


Assuntos
Acrodermatite/etiologia , Anticorpos Monoclonais/efeitos adversos , Síndrome de Linfonodos Mucocutâneos/tratamento farmacológico , Psoríase/etiologia , Acrodermatite/diagnóstico , Antebraço/patologia , Humanos , Lactente , Infliximab , Masculino , Síndrome de Linfonodos Mucocutâneos/complicações , Psoríase/diagnóstico
11.
J Exp Biol ; 212(Pt 24): 4072-8, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19946086

RESUMO

Ultrasonic hearing is widespread among moths, but very few moth species have been reported to produce ultrasounds for sexual communication. In those that do, the signals are intense and thus well matched for long distance communication. By contrast, males of the Asian corn borer moth (Crambidae) were recently shown to whisper extremely low-intensity ultrasonic courtship songs close to females. Since low sound levels will prevent eavesdropping by predators, parasites and conspecific rivals, we predicted low intensity ultrasound communication to be widespread among moths. Here we tested 13 species of moths including members of the Noctuidae, Arctiidae, Geometridae and Crambidae. Males of nine species, 70%, produced broadband ultrasound close to females. Peak frequencies ranged from 38 to above 100 kHz. All sounds were of low intensity, 43-76 dB SPL at 1 cm [64+/-10 dB peSPL (mean +/- s.d.), N=9 species]. These quiet and/or hyper-frequency ultrasounds are audible to nearby mates, but inaudible to unintended receivers. Although largely unknown because it is so inconspicuous, acoustic communication using low intensity ultrasound appears to be widespread among hearing moths. Thus, acoustic communication may be the norm rather than the exception.


Assuntos
Corte , Mariposas/fisiologia , Ultrassom , Vocalização Animal/fisiologia , Animais , Quirópteros/fisiologia , Feminino , Masculino , Pressão , Som
12.
Chem Commun (Camb) ; 53(17): 2630-2633, 2017 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-28195292

RESUMO

We report the synthesis and characterisation of palladium complexes bearing an N-heterocyclic carbene-phosphine oxide bidentate ligand and their use as catalysts for ethylene polymerisation and ethylene/polar monomer copolymerisation.

13.
Transplant Proc ; 49(7): 1634-1638, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28838454

RESUMO

BACKGROUND: We report a case of acute rejection of a liver graft, together with the occurrence of de novo donor-specific antibodies (DSAs), in a 53-year-old Japanese man who had undergone deceased-donor liver transplantation. METHODS: The graft rejection was triggered by low cyclosporine levels and pegylated interferon treatment for the recurrence of hepatitis C virus (HCV) infection 18 months after transplantation. Although the graft was ABO-compatible, pre-formed DSA B51 was detected; therefore, total plasma exchange was performed and intravenous rituximab (500 mg/body) was administered before transplantation. RESULTS: DSA was absent 6 months after transplantation. HCV recurrence was treated with pegylated interferon-α-2a. Renal function deteriorated with this anti-HCV therapy, with serum cyclosporine levels decreasing to 50 ng/mL. A rapid virologic response was achieved, but liver function deteriorated after 3 months of anti-HCV therapy, with histologic evidence of acute cellular rejection and formation of de novo DSAs. Anti-thymocyte globulin was administered for 5 days, which led to immediate improvement in liver function. However, renal function declined, warranting hemodialysis. The patient recovered 2 months after acute rejection, although de novo DSAs persisted. CONCLUSIONS: Careful immunologic monitoring may be required for patients receiving interferon therapy for HCV infection to maintain sufficient blood levels of immunosuppressive agents and to prevent acute liver graft rejection.


Assuntos
Antivirais/efeitos adversos , Ciclosporinas/sangue , Rejeição de Enxerto/induzido quimicamente , Interferon-alfa/efeitos adversos , Transplante de Fígado/efeitos adversos , Polietilenoglicóis/efeitos adversos , Anticorpos/imunologia , Especificidade de Anticorpos , Soro Antilinfocitário/uso terapêutico , Rejeição de Enxerto/sangue , Rejeição de Enxerto/imunologia , Hepacivirus/imunologia , Hepatite C Crônica/tratamento farmacológico , Hepatite C Crônica/virologia , Humanos , Imunossupressores/sangue , Masculino , Pessoa de Meia-Idade , Monitorização Imunológica , Plasmaferese , Complicações Pós-Operatórias/tratamento farmacológico , Complicações Pós-Operatórias/virologia , Proteínas Recombinantes/efeitos adversos , Recidiva , Doadores de Tecidos
14.
Biochim Biophys Acta ; 1252(2): 245-50, 1995 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-7578230

RESUMO

Cytochrome P-450 accepts electrons from electron transfer proteins to facilitate monooxidation reactions. It is suggested that basic amino acids such as Lys and Arg on the P-450 molecular surface interact with acidic amino acids such as Glu and Asp of the electron transfer protein. Safranine T is a basic compound which mediates electron transfer with illumination. It was found with flash photolysis that an electron from photo-reduced safranine T quickly reaches the heme iron of cytochrome P-450 1A2 (P-450 1A2). The photo-induced reduction kinetics of P-450 1A2 were analyzed by the Runge-Kutta method on the second order assumption. The electron-transfer rate constant from safranine T to P-450 1A2 was 2.1 x 10(6) M-1s-1. The rate constant was remarkably increased up to 3.1 x 10(8) M-1s-1 by adding cholic acid, while that was drastically reduced down to 3.5 x 10(4) M-1s-1 by adding Emulgen 913. The electron-transfer rate of a His163-Glu mutant, which has a 40 mV lower redox potential than that of the wild type, was the same as that of the wild type in the absence of the detergents, although the reduced fraction of the mutant was 30% lower than that of the wild type. The electron-transfer rate of the mutant also changed significantly by adding the detergents in the same way as the wild type. Based on these results, together with optical absorbance and fluorescence data, we discuss the inter- and intramolecular electron-transfer mechanism of P-450 1A2.


Assuntos
Sistema Enzimático do Citocromo P-450/química , Oxirredutases/química , Fenazinas/química , Animais , Ácido Cólico , Ácidos Cólicos , Citocromo P-450 CYP1A2 , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/isolamento & purificação , Detergentes , Cinética , Fígado/enzimologia , Mutação , Nonoxinol , Oxirredução , Oxirredutases/genética , Oxirredutases/isolamento & purificação , Fotoquímica , Ratos , Saccharomyces cerevisiae/enzimologia , Espectrometria de Fluorescência
15.
Diabetes ; 49(11): 1880-9, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11078455

RESUMO

To investigate the role of insulin receptor substrate (IRS)-2 in vivo, we generated IRS-2-deficient mice by gene targeting. Although homozygous IRS-2-deficient mice (IRS-2-/- mice) had a body weight similar to wild-type mice, they progressively developed type 2 diabetes at 10 weeks. IRS-2-/- mice showed insulin resistance and a defect in the insulin-stimulated signaling pathway in liver but not in skeletal muscle. Despite insulin resistance, the amount of beta-cells was reduced to 83% of that in wild-type mice, which was in marked contrast to the 85% increase in the amount of beta-cells in IRS-1-deficient mice (IRS-1-/- mice) to compensate for insulin resistance. Thus, IRS-2 plays a crucial role in the regulation of beta-cell mass. On the other hand, insulin secretion by the same number of cells in response to glucose measured ex vivo was significantly increased in IRS-2-/- mice compared with wild-type mice but was decreased in IRS-1-/- mice. These results suggest that IRS-1 and IRS-2 may play different roles in the regulation of beta-cell mass and the function of individual beta-cells.


Assuntos
Diabetes Mellitus Tipo 2/etiologia , Resistência à Insulina , Ilhotas Pancreáticas/patologia , Fígado/efeitos dos fármacos , Fosfoproteínas/deficiência , Fosfoproteínas/fisiologia , Animais , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patologia , Marcação de Genes , Hiperplasia , Insulina/metabolismo , Insulina/farmacologia , Proteínas Substratos do Receptor de Insulina , Secreção de Insulina , Peptídeos e Proteínas de Sinalização Intracelular , Ilhotas Pancreáticas/metabolismo , Fígado/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Camundongos Knockout , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Fosfoproteínas/genética , Transdução de Sinais/efeitos dos fármacos
18.
Endocrinology ; 124(6): 2659-65, 1989 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-2498061

RESUMO

To evaluate the possible existence of masked gonadotropin-binding sites and the functional role of the binding sites in porcine granulosa cells (GCs), we characterized the effects of neuraminidase (NA) pretreatment on [125I]human LH and [125I]human FSH binding to porcine GCs and the functionality of the unmasked receptors exposed by NA pretreatment. NA pretreatment at 37 C for 30 min increased specific FSH binding (P less than 0.01) and had no effect on LH binding to the GCs harvested from follicles of different sizes. Analysis of equilibrium binding experiments revealed that NA increased the number of FSH-binding sites without altering the affinity. In addition, pretreatment with NA resulted in progressive loss of cell membrane-bound sialic acid (P less than 0.01). To evaluate whether the unmasked FSH receptors constitute functional gonadotropin-binding sites, we measured the amounts of cAMP and 17 beta-estradiol produced by cultured GCs pretreated with NA. cAMP formation by GCs pretreated with NA was significantly (P less than 0.02) greater than that by GCs pretreated with medium alone in the presence of ovine FSH. Moreover, 17 beta-estradiol formation significantly increased (P less than 0.05) in GCs pretreated with NA compared with that in GCs pretreated with medium alone. However, there was no difference between medium-treated and NA-treated GCs in cAMP formation stimulated by forskolin. We suggest that porcine GCs contain a population of masked FSH-binding sites exposed by in vitro pretreatment of NA, and the binding sites constitute functional receptors capable of increasing cAMP and 17 beta-estradiol formation with FSH stimulation. Moreover, a possible involvement of plasma membrane-associated sialic acid in the masking/unmasking mechanism of FSH-binding sites was suggested.


Assuntos
Células da Granulosa/metabolismo , Neuraminidase/farmacologia , Receptores do FSH/metabolismo , Animais , Membrana Celular/metabolismo , Células Cultivadas , Feminino , Hormônio Foliculoestimulante/metabolismo , Cinética , Hormônio Luteinizante/metabolismo , Receptores do LH/metabolismo , Ácidos Siálicos/metabolismo , Suínos
19.
Endocrinology ; 133(5): 2127-32, 1993 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-8404662

RESUMO

Recent reports indicate that protein kinase C may play an important role in the process of gonadotropin-induced ovulation in the ovary. In the present study, we examined the effect of the protein kinase C inhibitor, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), on LH-stimulated tissue type plasminogen activator (tPA) activity in cultured rat granulosa cells. Granulosa cells were obtained from PMSG-treated rats and cultured for 48 h in the presence or absence of H-7 (0.1-60 microM) with ovine LH (30 ng/ml), phorbol 12-myristate 13-acetate (10(-8) M), phorbol 12,13-dibutyrate (10(-8) M), or (Bu)2cAMP (5 mM). After culture, tPA activity in the conditioned medium was assayed by fibrin autography technique after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. H-7 (1.0-60 microM) inhibited LH-, phorbol 12-myristate 13-acetate-, or phorbol 12,13-dibutyrate-stimulated tPA activity dose dependently, and each ID50 was approximately 8 microM. However, H-7 did not inhibit (Bu)2cAMP-stimulated tPA activity. To investigate the effect of H-7 on the ovulatory process in vivo, PMSG-treated immature rats were injected with H-7 (10(-9)-10(-3) M) into the unilateral ovarian bursa just before human CG administration. After 24 h, the number of oocyte-cumulus complexes in the oviduct was counted. H-7 suppressed the number of oocytes released from treated ovaries dose-dependently. The light microscopical observation revealed that ovaries treated with H-7 contained a few corpora lutea and many large unruptured follicles. The results of the present study suggest that the suppressive effects of H-7 on human CG-induced ovulation might be partly due to the inhibition of tPA secretion by rat granulosa cells via protein kinase C inhibition.


Assuntos
Células da Granulosa/metabolismo , Hormônio Luteinizante/farmacologia , Ovulação/efeitos dos fármacos , Proteína Quinase C/metabolismo , Ativador de Plasminogênio Tecidual/metabolismo , 1-(5-Isoquinolinasulfonil)-2-Metilpiperazina , Animais , Bucladesina/farmacologia , Células Cultivadas , Feminino , Gonadotropinas Equinas/farmacologia , Células da Granulosa/efeitos dos fármacos , Isoquinolinas/farmacologia , Ovário/citologia , Ovário/efeitos dos fármacos , Ovário/fisiologia , Dibutirato de 12,13-Forbol/farmacologia , Piperazinas/farmacologia , Proteína Quinase C/antagonistas & inibidores , Ratos , Ratos Sprague-Dawley , Acetato de Tetradecanoilforbol/farmacologia
20.
Endocrinology ; 131(3): 1063-8, 1992 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-1324147

RESUMO

In the present study we examined the existence of receptors for basic fibroblast growth factor (bFGF) and its regulation in rat granulosa cells. The binding of labeled bFGF to rat granulosa cells was dose-dependently displaced by unlabeled bFGF, but not other growth factors. FSH induced a dose-dependent increase in specific binding for bFGF to cultured rat granulosa cells. FSH treatment did not change the binding affinity (Kd, 2.8-3.0 x 10(-10) M) of the bFGF receptor, but increased the total number of bFGF-binding sites, whereas treatment with several steroid hormones had no effect on the specific binding of bFGF. Since cycloheximide, a protein synthesis inhibitor, inhibited the increase in bFGF binding induced by FSH, it is suggested that protein synthesis might be involved in the FSH stimulation of bFGF receptor induction. Furthermore, bFGF stimulated tissue plasminogen activator activity in a dose-dependent manner, and FSH-primed granulosa cells were more responsive to bFGF action, with a decrease in the ED50 from 5.0 to 1.5 ng/ml. The antibody against human bFGF neutralized the stimulatory effect of bFGF on tissue plasminogen activator secretion. The present study suggests that FSH induces functional receptors for bFGF in granulosa cells and that bFGF may play a role in the process of differentiation under the influence of FSH.


Assuntos
Fator 2 de Crescimento de Fibroblastos/metabolismo , Hormônio Foliculoestimulante/farmacologia , Células da Granulosa/metabolismo , Receptores de Superfície Celular/biossíntese , Animais , Anticorpos , Células Cultivadas , Cicloeximida/farmacologia , Relação Dose-Resposta a Droga , Feminino , Fator 2 de Crescimento de Fibroblastos/imunologia , Células da Granulosa/efeitos dos fármacos , Cinética , Hormônio Luteinizante/farmacologia , Prolactina/farmacologia , Ratos , Ratos Endogâmicos , Receptores de Superfície Celular/efeitos dos fármacos , Receptores de Superfície Celular/metabolismo , Receptores de Fatores de Crescimento de Fibroblastos , Ativador de Plasminogênio Tecidual/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA