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1.
Rev Sci Instrum ; 83(6): 063707, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22755634

RESUMO

Multi-beam interference (MBI) provides the ability to form a wide range of sub-micron periodic optical-intensity distributions with applications to a variety of areas, including photonic crystals (PCs), nanoelectronics, biomedical structures, optical trapping, metamaterials, and numerous subwavelength structures. Recently, pattern-integrated interference lithography (PIIL) was presented as a new lithographic method that integrates superposed pattern imaging with interference lithography in a single-exposure step. In the present work, the basic design and systematic implementation of a pattern-integrated interference exposure system (PIIES) is presented to realize PIIL by incorporating a projection imaging capability in a novel three-beam interference configuration. A fundamental optimization methodology is presented to model the system and predict MBI-patterning performance. To demonstrate the PIIL method, a prototype PIIES experimental configuration is presented, including detailed alignment techniques and experimental procedures. Examples of well-defined PC structures, fabricated with a PIIES prototype, are presented to demonstrate the potential of PIIL for fabricating dense integrated optical circuits, as well as numerous other subwavelength structures.

2.
Nat Genet ; 29(3): 345-9, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11687802

RESUMO

Hearing impairment affects about 1 in 1,000 children at birth. Approximately 70 loci implicated in non-syndromic forms of deafness have been reported in humans and 24 causative genes have been identified (see also http://www.uia.ac.be/dnalab/hhh). We report a mouse transcript, isolated by a candidate deafness gene approach, that is expressed almost exclusively in the inner ear. Genomic analysis shows that the human ortholog STRC (so called owing to the name we have given its protein-stereocilin), which is located on chromosome 15q15, contains 29 exons encompassing approximately 19 kb. STRC is tandemly duplicated, with the coding sequence of the second copy interrupted by a stop codon in exon 20. We have identified two frameshift mutations and a large deletion in the copy containing 29 coding exons in two families affected by autosomal recessive non-syndromal sensorineural deafness linked to the DFNB16 locus. Stereocilin is made up of 1,809 amino acids, and contains a putative signal petide and several hydrophobic segments. Using immunohistolabeling, we demonstrate that, in the mouse inner ear, stereocilin is expressed only in the sensory hair cells and is associated with the stereocilia, the stiff microvilli forming the structure for mechanoreception of sound stimulation.


Assuntos
Cromossomos Humanos Par 15/genética , Células Ciliadas Auditivas/metabolismo , Perda Auditiva Neurossensorial/genética , Mutação/genética , Proteínas/genética , Sequência de Aminoácidos , Animais , Pré-Escolar , Mapeamento Cromossômico , Clonagem Molecular , Consanguinidade , Análise Mutacional de DNA , Éxons/genética , Perfilação da Expressão Gênica , Marcadores Genéticos/genética , Humanos , Peptídeos e Proteínas de Sinalização Intercelular , Masculino , Proteínas de Membrana , Camundongos , Microscopia de Fluorescência , Dados de Sequência Molecular , Proteínas/química , RNA Mensageiro/análise , RNA Mensageiro/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sequências de Repetição em Tandem/genética
3.
Nat Genet ; 26(1): 51-5, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10973247

RESUMO

Usher syndrome type 1 (USH1) is an autosomal recessive sensory defect involving congenital profound sensorineural deafness, vestibular dysfunction and blindness (due to progressive retinitis pigmentosa)1. Six different USH1 loci have been reported. So far, only MYO7A (USH1B), encoding myosin VIIA, has been identified as a gene whose mutation causes the disease. Here, we report a gene underlying USH1C (MIM 276904), a USH1 subtype described in a population of Acadian descendants from Louisiana and in a Lebanese family. We identified this gene (USH1C), encoding a PDZ-domain-containing protein, harmonin, in a subtracted mouse cDNA library derived from inner ear sensory areas. In patients we found a splice-site mutation, a frameshift mutation and the expansion of an intronic variable number of tandem repeat (VNTR). We showed that, in the mouse inner ear, only the sensory hair cells express harmonin. The inner ear Ush1c transcripts predicted several harmonin isoforms, some containing an additional coiled-coil domain and a proline- and serine-rich region. As several of these transcripts were absent from the eye, we propose that USH1C also underlies the DFNB18 form of isolated deafness.


Assuntos
Proteínas de Transporte/genética , Mutação da Fase de Leitura , Células Ciliadas Auditivas Internas/patologia , Perda Auditiva Neurossensorial/genética , Mutação , Degeneração Retiniana/genética , Proteínas Adaptadoras de Transdução de Sinal , Alelos , Animais , Sequência de Bases , Northern Blotting , Proteínas de Transporte/biossíntese , Proteínas de Transporte/química , Proteínas de Ciclo Celular , Proteínas do Citoesqueleto , Análise Mutacional de DNA , DNA Complementar/metabolismo , Éxons , Saúde da Família , Deleção de Genes , Biblioteca Gênica , Células Ciliadas Auditivas Internas/metabolismo , Células Ciliadas Vestibulares/metabolismo , Heterozigoto , Humanos , Imuno-Histoquímica , Íntrons , Camundongos , Repetições Minissatélites/genética , Modelos Genéticos , Dados de Sequência Molecular , Linhagem , Isoformas de Proteínas , Estrutura Terciária de Proteína , Splicing de RNA/genética , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Homologia de Sequência do Ácido Nucleico , Distribuição Tecidual , Transcrição Gênica
4.
Proc Natl Acad Sci U S A ; 96(2): 529-34, 1999 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-9892667

RESUMO

During the course of a study aimed at identifying inner ear-specific transcripts, a 1,906-bp murine cDNA predicted to encode a secreted 469-aa protein with two domains of homology with the secreted phospholipases A2 was isolated. This transcript is specifically expressed in the inner ear from embryonic day 9.5. The encoded 95-kDa glycoprotein is the major protein of the utricular and saccular otoconia and thus was named otoconin-95. By immunohistofluorescence, otoconin-95 also was detected in the cupulae of the semicircular canals and in previously undescribed transient granular structures of the cochlea. Otoconin-95 was found to be synthesized by various nonsensory cell types, but not by the supporting cells of the sensory epithelia, which produce the otoconial precursor vesicles. In addition, multiple isoforms generated by differential splicing were observed in different combinations during development. Based on the present results, we propose a model for the formation of the otoconia.


Assuntos
Calcificação Fisiológica/genética , Glicoproteínas/genética , Membrana dos Otólitos/química , Processamento Alternativo/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Proteínas de Ligação ao Cálcio , Clonagem Molecular , Orelha/crescimento & desenvolvimento , Desenvolvimento Embrionário e Fetal , Proteínas da Matriz Extracelular , Imunofluorescência , Regulação da Expressão Gênica no Desenvolvimento/genética , Glicoproteínas/química , Imuno-Histoquímica , Hibridização In Situ , Camundongos , Dados de Sequência Molecular , Membrana dos Otólitos/embriologia , Fosfolipases A/genética , RNA Mensageiro/genética , Análise de Sequência de DNA
5.
Health Care Manag ; 3(1): 1-7, 1997 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10169491

RESUMO

Despite increasing demand and numerous problems associated with its delivery, long-term care has been largely ignored in the recent debates over health care reform. The gap between concept and reality is explored in detail, along with possible approaches to the creation of a system that is humane, fair, and equitable.


Assuntos
Assistência de Longa Duração , Responsabilidade Social , Criança , Reforma dos Serviços de Saúde , Humanos , Seguro de Assistência de Longo Prazo , Medicaid , Medicare , Qualidade da Assistência à Saúde , Estados Unidos
6.
Health Care Manag ; 3(1): 77-86, 1997 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10169504

RESUMO

The pharmacotherapeutic approach to patient management in long-term care is fraught with uncertainties and perils, including overprescription, overmedication, and adverse drug events as well as escalating costs. The author argues for alternative protocols that emphasize behavior modification, exercise, supervised hydration, and well-monitored nutrition.


Assuntos
Revisão de Uso de Medicamentos , Assistência de Longa Duração/normas , Sistemas de Medicação , Síndrome da Imunodeficiência Adquirida/complicações , Idoso , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Gastroenteropatias/tratamento farmacológico , Humanos , Doenças do Sistema Nervoso/tratamento farmacológico , Fenômenos Fisiológicos da Nutrição , Doenças Respiratórias/tratamento farmacológico , Tuberculose/complicações , Tuberculose/tratamento farmacológico , Estados Unidos
7.
Nat Genet ; 15(2): 157-64, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9020840

RESUMO

A candidate gene for Branchio-Oto-Renal (BOR) syndrome was identified at chromosome 8q13.3 by positional cloning and shown to underlie the disease. This gene is a human homologue of the Drosophila eyes absent gene (eya), and was therefore called EYA1. A highly conserved 271-amino acid C-terminal region was also found in the products of two other human genes (EYA2 and EYA3), demonstrating the existence of a novel gene family. The expression pattern of the murine EYA1 orthologue, Eya1, suggests a role in the development of all components of the inner ear, from the emergence of the otic placode. In the developing kidney, the expression pattern is indicative of a role for Eya1 in the metanephric cells surrounding the 'just-divided' ureteric branches.


Assuntos
Síndrome Brânquio-Otorrenal/genética , Proteínas de Drosophila , Drosophila melanogaster/genética , Proteínas do Olho/genética , Genes , Família Multigênica , Proteínas/genética , Transativadores , Adulto , Sequência de Aminoácidos , Animais , Sequência de Bases , Região Branquial/embriologia , Clonagem Molecular , DNA Complementar/genética , Orelha Interna/embriologia , Orelha Média/embriologia , Desenvolvimento Embrionário e Fetal/genética , Éxons/genética , Proteínas do Olho/fisiologia , Proteínas Fetais/biossíntese , Proteínas Fetais/genética , Regulação da Expressão Gênica no Desenvolvimento , Biblioteca Gênica , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Rim/embriologia , Camundongos , Dados de Sequência Molecular , Proteínas Nucleares , Biossíntese de Proteínas , Proteínas Tirosina Fosfatases , Proteínas/fisiologia , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Especificidade da Espécie
8.
Nat Genet ; 15(2): 186-9, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9020846

RESUMO

The Jervell and Lange-Nielsen (JLN) syndrome (MIM 220400) is an inherited autosomal recessive disease characterized by a congenital bilateral deafness associated with a QT prolongation on the electrocardiogram, syncopal attacks due to ventricular arrhythmias and a high risk of sudden death. JLN syndrome is a rare disease, which seems to affect less than one percent of all deaf children. Linkage to chromosome 11p15.5 markers was found by analysing four consanguinous families. Recombinants allowed us to map the JLN gene between D11S922 and D11S4146, to a 6-cM interval where KVLQT1, a potassium channel gene causing Romano-Ward (RW) syndrome, the dominant form of long QT syndrome, has been previously localized. An homozygous deletion-insertion event (1244, -7 +8) in the C-terminal domain of this gene was detected in three affected children of two families. We found that KVLQT1 is expressed in the stria vascularis of mouse inner ear by in situ hybridization. Taken together, our data indicate that KVLQT1 is responsible for both JLN and RW syndromes and has a key role not only in the ventricular repolarization but also in normal hearing, probably via the control of endolymph homeostasis.


Assuntos
Surdez/genética , Perda Auditiva Bilateral/genética , Síndrome do QT Longo/genética , Canais de Potássio de Abertura Dependente da Tensão da Membrana , Canais de Potássio/genética , Deleção de Sequência , Adulto , Animais , Pré-Escolar , Consanguinidade , Análise Mutacional de DNA , Surdez/fisiopatologia , Morte Súbita Cardíaca/etiologia , Orelha Interna/irrigação sanguínea , Endolinfa/fisiologia , Feminino , Perda Auditiva Bilateral/fisiopatologia , Sistema de Condução Cardíaco/fisiopatologia , Humanos , Hibridização In Situ , Lactente , Canais de Potássio KCNQ , Canal de Potássio KCNQ1 , Síndrome do QT Longo/fisiopatologia , Masculino , Camundongos , Dados de Sequência Molecular , Linhagem , Polimorfismo Conformacional de Fita Simples
9.
Proc Natl Acad Sci U S A ; 94(26): 14450-5, 1997 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-9405633

RESUMO

Efforts to identify the specific components of the mammalian inner ear have been hampered by the small number of neuroepithelial cells and the variety of supporting cells. To circumvent these difficulties, we used a PCR-based subtractive method on cDNA from 2-day-old mouse cochlea. A cDNA encoding a predicted 2910-amino acid protein related to mucin has been isolated. Several lines of evidence indicate, however, that this protein does not undergo the O-glycosylation characteristic to mucins. As confirmed by immunocytochemistry and biochemical experiments, this protein is specific to the inner ear. Immunohistofluorescence labeling showed that this protein is a component of all the acellular membranes of the inner ear: i.e., the tectorial membrane of the cochlea, the otoconial and accessory membranes of the utricule and saccule, the cupula of the semicircular canals, and a previously undescribed acellular material covering the otoconia of the saccule. The protein has been named otogelin with reference to its localization. A variety of nonsensory cells located underneath these membranes could be identified as synthesizing otogelin. Finally, this study revealed a maturation process of the tectorial membrane, as evidenced by the progressive organization of otogelin labeling into thick and spaced radial fiber-like structures.


Assuntos
Orelha Interna/metabolismo , Glicoproteínas/genética , Glicoproteínas de Membrana/genética , Sequência de Aminoácidos , Animais , Clonagem Molecular , DNA Complementar/genética , DNA Complementar/isolamento & purificação , Orelha Interna/anatomia & histologia , Técnica Indireta de Fluorescência para Anticorpo , Glicoproteínas/metabolismo , Glicoproteínas de Membrana/metabolismo , Camundongos , Dados de Sequência Molecular , Análise de Sequência
10.
Brain Res Dev Brain Res ; 97(1): 76-87, 1996 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-8946056

RESUMO

Insulin-like growth factor type 1 receptor (IGF-1R) is a tyrosine kinase with a key role in development. The primary structure of IGF-1R is known for mammalian species, but not for birds. The avian embryo, however, provides an ideal system for the experimental study of neurogenesis. We therefore cloned the complete coding sequence of the chicken IGF-1R from a cDNA library and analyzed its embryonic expression by Northern blot and in situ hybridization. The deduced chicken IGF-1R precursor of 1363 amino acids was 85% identical to human IGF-1R and did not show deletions or insertions in critical positions, when compared to its mammalian homologues. Notably, all cysteine residues in the extracellular domains, and 15 of the 17 N-linked glycosylation sites found in human IGF-1R were also present in the chicken receptor. An 11 kb transcript was abundant in developing nervous tissues, kidney, pancreas and the gastrointestinal tract. The early in situ expression patterns in 20-somite embryos revealed high levels of IGF-1R mRNA in the neuroepithelia, notochord and somites. At embryonic day 4 (E4), high concentrations of IGF-1R transcripts were found again primarily in the neuroepithelia and, to a lesser degree, in the sensory ganglia and diverse mesenchymal derivatives. During the second half of embryonic development, IGF-1R expression in the CNS was particularly abundant in telencephalic regions, including the olfactory bulb, hippocampus, striatum and piriform cortex, and also in the optic tectum and cerebellum. By the use of cDNA cloning and in situ hybridization this study reveals conserved amino acid sequence elements between birds and mammals, and developmental expression patterns that are compatible with an important role of this receptor in growth, differentiation and maturation of the avian CNS.


Assuntos
Sequência Conservada , Sistema Nervoso/embriologia , Receptor IGF Tipo 1/genética , Animais , Northern Blotting , Embrião de Galinha , Clonagem Molecular , DNA Complementar/análise , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Hibridização In Situ , Mamíferos , Dados de Sequência Molecular , RNA Mensageiro/análise , Homologia de Sequência de Aminoácidos
11.
Dev Biol ; 175(1): 118-31, 1996 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-8608858

RESUMO

The bird olfactory system has a simple structure and affords an attractive developmental model for the study of olfactory morphogenesis and differentiation. We have cloned and characterized several chick olfactory receptor (COR) genes belonging to the superfamily of seven-transmembrane domain proteins. In situ hybridization analysis of their spatiotemporal patterns of expression during development reveals several important characteristics. COR expression starts early in placodal cells (Embryonic Day 5, E5). Changes in their expression pattern then correlate with the onset of synaptogenesis (E8). The adult pattern, achieved before hatching, shows that cells expressing a particular COR are not regionalized within the epithelium. By double-label in situ hybridization, we clearly demonstrate that a single cell does not coexpress different COR genes (or subsets of CORs) at any stage of development. Following bulbar deafferentation, COR expression ceases more rapidly than expected from previous axotomy experiments. Concomitantly, a reactivation of the Cash-1 gene, which is involved in early neuronal specification, could be an early sign of olfactory neuronal regeneration. Modulation of COR and Cash-1 expression points to a simultaneous process of neuronal degeneration and regeneration in the olfactory epithelium after axotomy. COR expression is restricted to the olfactory epithelium except during early stages (before synaptogenesis). At that time, cells distributed along the olfactory nerve, from the placode to the anterior telencephalon, also express CORs. This cell population is different from the luteinizing hormone releasing hormone neurons migrating from the placode. Our results show that the olfactory neurons or neuroblasts choose to express one COR before establishing functional connections with the bulb. Later on, bulboepithelial connections seem important not only for olfactory neuron survival but also for stimulation of COR expression. In addition, beyond their implication in functional odor detection, CORs could be involved, at early stages, in processes of olfactory morphogenesis, including the establishment of a bulbar chemotopy.


Assuntos
Proteínas Aviárias , Neurônios Receptores Olfatórios/embriologia , Receptores Odorantes/biossíntese , Sequência de Aminoácidos , Animais , Sequência de Bases , Fatores de Transcrição Hélice-Alça-Hélice Básicos , Southern Blotting , Embrião de Galinha , Galinhas , Proteínas de Ligação a DNA/biossíntese , Feminino , Expressão Gênica , Biblioteca Genômica , Imuno-Histoquímica , Hibridização In Situ , Masculino , Proteínas de Membrana/biossíntese , Proteínas de Membrana/genética , Dados de Sequência Molecular , Bulbo Olfatório/embriologia , RNA Mensageiro/genética , Receptores Odorantes/genética , Homologia de Sequência de Aminoácidos , Fatores de Tempo , Fatores de Transcrição/biossíntese
13.
Health Care Manag ; 2(1): 61-70, 1995 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10165643

RESUMO

The need to control governmental health expenditures has led to experiments with mandated managed care for Medicaid recipients. Loss of freedom to choose care providers was considered a worthy sacrifice. The authors examine the historical and legislative background, including research and demonstration projects. Although they view some form of rationing as inevitable, they argue that Medicaid recipients should not be singled out to bear the main part of the burden.


Assuntos
Participação da Comunidade/legislação & jurisprudência , Programas de Assistência Gerenciada/estatística & dados numéricos , Medicaid/legislação & jurisprudência , Planos Governamentais de Saúde/legislação & jurisprudência , Serviço Hospitalar de Emergência/estatística & dados numéricos , Mau Uso de Serviços de Saúde , Pesquisa sobre Serviços de Saúde , Kentucky , Programas de Assistência Gerenciada/legislação & jurisprudência , Medicaid/organização & administração , Projetos Piloto , Estados Unidos , Wisconsin
14.
Health Care Manag ; 1(1): 135-44, 1994 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10152349

RESUMO

Today's health care professionals must deal with problems of financial viability, competitiveness, quality control, and consumer focus. The major theme of this article is how appropriate is the education system that trains and prepares health care managers for these challenges. Because we are not in the health care business, but rather in the business of managing health care, the authors suggest that a new educational paradigm that incorporates indepth study of business disciplines be the health administration educational model for the 21st century. Whether or not the proposed model is alien to our basic traditional concepts of health care management, the viability of our institutions will be at stake if they do not implement a healthy business protocol to the services they provide.


Assuntos
Reforma dos Serviços de Saúde/tendências , Administração Hospitalar/educação , Modelos Educacionais , Educação de Pós-Graduação , Reforma dos Serviços de Saúde/legislação & jurisprudência , Administração Hospitalar/tendências , Liderança , Inovação Organizacional , Estados Unidos
15.
Proc Natl Acad Sci U S A ; 90(6): 2461-5, 1993 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-8460158

RESUMO

The human KAL gene is responsible for the X chromosome-linked Kallmann syndrome. A partial cDNA sequence from the chicken KAL homologue was determined and used to study expression of the KAL gene, by in situ hybridization, during chicken development, from day 6 of incubation. The KAL gene is mainly expressed in neurons of the central nervous system during the second half of embryonic life. High levels of transcript were detected in mitral neurons of the olfactory bulbs, in striatal neurons, in Purkinje cells of the cerebellum, in retinal neurons, and in isolated neurons of the brainstem and spinal cord. No expression was observed in glial cells. A low level of expression was observed in some mesenchymal derivatives. In the adult, expression is maintained or increased in several neuronal populations, especially in optic tectum and striatum. A possible role for the KAL protein in synaptogenesis at these stages is discussed. These results in the chicken embryo help to elucidate the mechanisms of anosmia and gonadotropin-releasing hormone deficiency, which define Kallmann syndrome. In addition, most of the occasional symptoms described in Kallmann syndrome patients, such as cerebellar ataxia, abnormal ocular movements, abnormal spatial visual attention, mirror movements, and renal aplasia, could be ascribed to malfunction of areas that, in the chicken, express the KAL gene.


Assuntos
Encéfalo/embriologia , Proteínas da Matriz Extracelular , Proteínas do Tecido Nervoso/genética , Neurônios/fisiologia , Sequência de Aminoácidos , Animais , Sequência de Bases , Northern Blotting , Encéfalo/citologia , Embrião de Galinha , Galinhas , Éxons , Biblioteca Genômica , Humanos , Hibridização In Situ , Dados de Sequência Molecular , Neurônios/citologia , Reação em Cadeia da Polimerase , Células de Purkinje/citologia , RNA Mensageiro/análise , RNA Mensageiro/genética , Retina/citologia , Retina/embriologia , Homologia de Sequência de Aminoácidos
16.
Mol Cell Biol ; 12(8): 3548-55, 1992 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-1352852

RESUMO

In eukaryotic cells, nucleus-cytoplasm exchanges play an important role in genomic regulation. We have analyzed the localization of four nuclear antigens in different growth conditions: two replicative proteins, DNA polymerase alpha and proliferating cell nuclear antigen (PCNA), and two oncogenic regulatory proteins, c-Myc and c-Fos. A kinetic study of subcellular localization of these proteins has been done. In cultures in which cells were sparse, these proteins were detected in the nucleus. When proliferation was stopped by the high density of culture cells or by serum starvation, these proteins left the nucleus for the cytoplasm with different kinetics. DNA polymerase alpha is the first protein to leave the nucleus, with the PCNA protein, c-Fos, and c-Myc leaving the nucleus later. In contrast, during serum stimulation c-Fos and c-Myc relocalize into the nucleus before the replicative proteins. We also noticed that in sparse cell cultures, 10% of the cells exhibit a perinuclear staining for the DNA polymerase alpha, PCNA, and c-Myc proteins but not for c-Fos. This peculiar staining was also observed as an initial step to nuclear localization after serum stimulation and in vivo in Xenopus embryos when the G1 phase is reintroduced in the embryonic cell cycle at the mid-blastula stage. We suggest that such staining could reflect specific structures involved in the initiation of the S phase.


Assuntos
Ciclo Celular/fisiologia , DNA Polimerase II/metabolismo , Proteínas Nucleares/metabolismo , Proteínas Proto-Oncogênicas c-fos/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Células 3T3 , Animais , Autoantígenos/metabolismo , Linhagem Celular , Núcleo Celular/metabolismo , DNA Polimerase II/análise , Embrião não Mamífero/fisiologia , Cinética , Camundongos , Proteínas Nucleares/análise , Antígeno Nuclear de Célula em Proliferação , Proteínas Proto-Oncogênicas c-fos/análise , Proteínas Proto-Oncogênicas c-myc/análise , Frações Subcelulares/metabolismo , Xenopus laevis
17.
J Cell Sci ; 102 ( Pt 1): 63-9, 1992 May.
Artigo em Inglês | MEDLINE | ID: mdl-1354219

RESUMO

The immunocytological distribution of the proliferating cell nuclear antigen (PCNA), a protein involved in DNA replication, has been examined during the early development of Xenopus laevis. The protein is uniformly detected in nuclei during early stages up to the neurula stage. PCNA is detected by its distinctive cyclical pattern during early development, remaining detectable only during the period of S phase of each cell cycle. Immunological detection of PCNA is therefore a useful and specific non-isotopic marker of S-phase cells in the embryo. PCNA associates with typical karyomeric structures, suggesting that DNA replication starts before the nuclear compartment is entirely formed. At the midblastula transition, a new pattern of PCNA staining becomes apparent. First, a new type of PCNA staining is detected at the nuclear periphery. Second, mitotic clusters with different PCNA distributions suggest that the onset of desynchronization of the cell cycle at this stage is not random.


Assuntos
Ciclo Celular/fisiologia , Núcleo Celular/metabolismo , Embrião não Mamífero/fisiologia , Proteínas Nucleares/isolamento & purificação , Xenopus laevis/embriologia , Animais , Blastocisto/química , Blastocisto/metabolismo , Núcleo Celular/química , Embrião não Mamífero/metabolismo , Desenvolvimento Embrionário , Fertilização/fisiologia , Cinética , Proteínas Nucleares/metabolismo , Antígeno Nuclear de Célula em Proliferação
18.
Dev Biol ; 141(1): 183-92, 1990 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-1697269

RESUMO

The coding sequence of the proliferating cell nuclear antigen (PCNA) was characterized in the amphibian Xenopus laevis. The deduced protein sequence shares an extensive homology (89%) with the mammalian PCNA coding sequences. Xenopus PCNA is expressed beginning in early oogenesis and reaches a level of 3 X 10(7) transcripts per mature oocyte, whereas proliferative somatic cells contain 3 X 10(2) PCNA transcripts per cell. Most of the PCNA protein is expressed during late oogenesis and one single stage VI oocyte contains the amount of PCNA protein present in 4 X 10(5) somatic cells in culture. Thus most, if not all, of the PCNA required for early development is stored as a maternal gene product. Part of the mRNA stockpile is degraded during the cleavage stage and then new PCNA zygotic expression at the neurula stage maintains a constitutive value of 30 transcripts per cell until the tailbud stage. The maternal protein is maintained at a constant level during embryonic development at least until the swimming tadpole stage. The protein is localized in the nuclei at all stages of oogenesis and development that were examined.


Assuntos
Autoantígenos/genética , Proteínas Nucleares/genética , Xenopus/embriologia , Sequência de Aminoácidos , Animais , Autoantígenos/biossíntese , Sequência de Bases , Northern Blotting , Western Blotting , Divisão Celular/fisiologia , Técnicas In Vitro , Dados de Sequência Molecular , Proteínas Nucleares/biossíntese , Hibridização de Ácido Nucleico , Oogênese , Antígeno Nuclear de Célula em Proliferação , Biossíntese de Proteínas , RNA/análise , Homologia de Sequência do Ácido Nucleico , Transcrição Gênica
19.
Int J Dev Biol ; 34(1): 51-9, 1990 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-1975504

RESUMO

Our laboratory is studying genes involved in the regulation of the balance between cell growth and differentiation during embryonic development in Xenopus. We have analyzed the developmental expression of the proto-oncogenes c-myc, and KiRas 2B, the proliferating cell nuclear antigen (PCNA), and the tumor suppressor gene p53. These genes, usually expressed during cell proliferation, are expressed in the oocyte in large quantities, but the majority of their maternal RNAs are degraded by the gastrula stage. The expression of c-myc and the localization of the protein indicate that c-myc has the characteristics expected for a gene involved in the regulation of the mid-blastula transition, when zygotic expression is turned on in the embryo. Its expression during late development or during regeneration indicates that it enables the cells to remain competent for cycling during organogenesis. In vitro systems that reproduce the principal cellular functions during early development are used as model systems to understand the mechanisms involved in early embryogenesis.


Assuntos
Embrião não Mamífero/fisiologia , Expressão Gênica , Proto-Oncogenes , Xenopus laevis/embriologia , Animais , Divisão Celular , Feminino , Modelos Biológicos , Proteínas Nucleares/genética , Oócitos/fisiologia , Antígeno Nuclear de Célula em Proliferação , Proteínas Tirosina Quinases/genética , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas c-myc , Xenopus laevis/genética
20.
Artigo em Romano | MEDLINE | ID: mdl-2532772

RESUMO

The present paper reports on a case of malignant melanoma of the iris masked by a relapsing iridocyclitis. The authors discuss the pathophysiological processes that may accompany the tumour.


Assuntos
Neoplasias da Íris/diagnóstico , Melanoma/diagnóstico , Adulto , Diagnóstico Diferencial , Feminino , Humanos , Iridociclite/diagnóstico , Iris/patologia , Iris/cirurgia , Neoplasias da Íris/patologia , Neoplasias da Íris/cirurgia , Melanoma/patologia , Melanoma/cirurgia , Recidiva
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