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1.
Mol Hum Reprod ; 27(6)2021 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-34009290

RESUMO

Male infertility affects about 7% of the general male population. Balanced structural chromosomal rearrangements are observed in 0.4-1.4% of infertile males and are considered as a well-established cause of infertility. However, underlying pathophysiological mechanisms still need to be clarified. A strategy combining standard and high throughput cytogenetic and molecular technologies was applied in order to identify the candidate genes that might be implicated in the spermatogenesis defect in three male carriers of different balanced translocations. Fluorescence in situ hybridization (FISH) and whole-genome paired-end sequencing were used to characterize translocation breakpoints at the molecular level while exome sequencing was performed in order to exclude the presence of any molecular event independent from the chromosomal rearrangement in the patients. All translocation breakpoints were characterized in the three patients. We identified four variants: a position effect on LACTB2 gene in Patient 1, a heterozygous CTDP1 gene disruption in Patient 2, two single-nucleotide variations (SNVs) in DNAH5 gene and a heterozygous 17q12 deletion in Patient 3. The variants identified in this study need further validation to assess their roles in male infertility. This study shows that beside the mechanical effect of structural rearrangement on meiosis, breakpoints could result in additional alterations such as gene disruption or position effect. Moreover, additional SNVs or copy number variations may be fortuitously present and could explain the variable impact of chromosomal rearrangements on spermatogenesis. In conclusion, this study confirms the relevance of combining different cytogenetic and molecular techniques to investigate patients with spermatogenesis disorders and structural rearrangements on genomic scale.


Assuntos
Estudos de Associação Genética/métodos , Sequenciamento de Nucleotídeos em Larga Escala , Infertilidade Masculina/genética , Espermatogênese/genética , Translocação Genética , Adulto , Astenozoospermia/genética , Dineínas do Axonema/genética , Sequência de Bases , Pontos de Quebra do Cromossomo , Humanos , Hibridização in Situ Fluorescente , Masculino , Pessoa de Meia-Idade , Fosfoproteínas Fosfatases/genética , Polimorfismo de Nucleotídeo Único , Sequenciamento do Exoma , Sequenciamento Completo do Genoma , beta-Lactamases/genética
2.
Hum Reprod ; 33(12): 2162-2167, 2018 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-30357338

RESUMO

The accurate genetic screening of pre-implantation embryos currently entails the use of technically challenging and biologically invasive biopsies of the human embryos. Investigating a more conservative sampling approach has emerged as a timely and desired alternative. Circulating cell-free embryonic DNA is present in the blastocoel fluid and spent culture media of blastocysts, and this has lately been sought as an attractive source of genetic information. The genetic analysis of cell-free embryonic DNA has been reported, to be useful in evaluating the genetic constitution of embryos; thus, providing a potential alternative to conventional biopsy-derived pre-implantation genetic testing (PGT). In this review, we have summarized these non-invasive alternative applications of PGT and discussed their current limitations and future clinical implications.


Assuntos
Blastocisto , Testes Genéticos , Diagnóstico Pré-Implantação , Técnicas de Cultura Embrionária , Feminino , Fertilização in vitro , Humanos , Gravidez
3.
Clin Genet ; 86(2): 177-80, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25180400

RESUMO

To create a diagnostic document describing the utilization of pre-implantation genetic testing (PGT) in the absence of monitoring and regulation. Retrospective cohort study of couples undergoing PGT between 2004 and 2007 in Lebanon. The clinical indications for 192 PGT cycles performed during the study period were gender selection (96.3%), chromosomal aneuploidy (3.1%), and balanced translocation (0.5%). When gender selection was sought, the selection of a son was desired in 94.1% of cases. Of couples undergoing PGT for sex selection, 16.2% were childless, 8.6% had one child of the opposite gender, 28.1% had two same-gender children, 29.7% had three same-gender children, and 11.9% had four or more. Our findings demonstrate the morally questionable consequences of self-regulated systems in which physicians are the sole gatekeepers of norms and ethics.


Assuntos
Governança Clínica , Testes Genéticos/estatística & dados numéricos , Diagnóstico Pré-Implantação/estatística & dados numéricos , Feminino , Humanos , Masculino
5.
Clin Exp Obstet Gynecol ; 40(3): 327-30, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24283158

RESUMO

OBJECTIVE: To evaluate the ovarian response to ovarian stimulation in women with idiopathic premature ovarian failure (POF) in a prospective, controlled, and sequential crossover pilot study. MATERIALS AND METHODS: Ten women with idiopathic premature ovarian failure and normal karyotype were included in the study. Phase I was comprised of three consecutive control cycles consisting each of estrogen progestin sequential therapy. Phase II was comprised of three consecutive treatment cycles combining the use of gonadotropin-releasing hormone agonist (GnRHa) in the background of estrogen priming, followed by gonadotropin ovarian stimulation and corticosteroid immunosuppression. RESULTS: Ovulation rates in the treatment cycles (0/10; 0%) did not differ from control cycles (0/10; 0%). CONCLUSIONS: The findings of this pilot study showed that the combination of estrogen priming, corticosteroid immune-suppression, GnRHa pituitary desensitization, and followed by gonadotropin ovarian stimulation is ineffective in restoring ovarian function in women with idiopathic POF.


Assuntos
Indução da Ovulação/métodos , Insuficiência Ovariana Primária/terapia , Adolescente , Adulto , Protocolos Clínicos , Feminino , Humanos , Projetos Piloto , Insuficiência Ovariana Primária/fisiopatologia , Adulto Jovem
6.
J Med Genet ; 47(12): 797-802, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19643772

RESUMO

Microcephalic osteodysplastic primordial dwarfism type II (MOPD II, MIM 210720) and Seckel syndrome (SCKL, MIM 210600) belong to the primordial dwarfism group characterised by intrauterine growth retardation, severe proportionate short stature, and pronounced microcephaly. MOPD II is distinct from SCKL by more severe growth retardation, radiological abnormalities, and absent or mild mental retardation. Seckel syndrome is associated with defective ATR dependent DNA damage signalling. In 2008, loss-of-function mutations in the pericentrin gene (PCNT) have been identified in 28 patients, including 3 SCKL and 25 MOPDII cases. This gene encodes a centrosomal protein which plays a key role in the organisation of mitotic spindles. The aim of this study was to analyse PCNT in a large series of SCKL-MOPD II cases to further define the clinical spectrum associated with PCNT mutations. Among 18 consanguineous families (13 SCKL and 5 MOPDII) and 6 isolated cases (3 SCKL and 3 MOPD II), 13 distinct mutations were identified in 5/16 SCKL and 8/8 MOPDII including five stop mutations, five frameshift mutations, two splice site mutations, and one apparent missense mutation affecting the last base of exon 19. Moreover, we demonstrated that this latter mutation leads to an abnormal splicing with a predicted premature termination of translation. The clinical analysis of the 5 SCKL cases with PCNT mutations showed that they all presented minor skeletal changes and clinical features compatible with MOPDII diagnosis. It is therefore concluded that, despite variable severity, MOPDII is a genetically homogeneous condition due to loss-of-function of pericentrin.


Assuntos
Antígenos/genética , Estudos de Coortes , Consanguinidade , Nanismo/diagnóstico por imagem , Nanismo/genética , Família , Feminino , Ligação Genética , Loci Gênicos/genética , Genótipo , Crescimento e Desenvolvimento/genética , Mãos/diagnóstico por imagem , Quadril/diagnóstico por imagem , Humanos , Perna (Membro)/diagnóstico por imagem , Masculino , Microcefalia/diagnóstico por imagem , Microcefalia/genética , Mutação/genética , Radiografia
7.
Int J Cosmet Sci ; 33(5): 432-42, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21401652

RESUMO

One of the main functions of the skin is to protect the organism against environmental threats, such as thermal stress. Aquaporin-3 (AQP3) facilitates water and glycerol transport across cell membranes and therefore regulates osmotic balance in different situations of stress. This mechanism seems to be particularly important for the resistance of different organisms to cold stress. Consequently, we were interested in investigating the effect of cold and osmotic stress on AQP3 expression in normal human keratinocytes. We developed a new active ingredient to stimulate aquaporins in skin and demonstrated the partial restoration of AQP3 expression in keratinocytes transfected with AQP3 siRNA. Moreover, we examined the effect of cold stress on cell morphology and the impact of a pre-treatment with the active ingredient. Our results indicated that induction of AQP3 helped maintain a correct organization of the actin cytoskeleton, preserving cell morphology and preventing cells from rounding. Immunofluorescent staining revealed cytoplasmic localization of AQP3 and its translocation to the cell membrane following osmotic stress. Histological ex vivo studies of skin under different conditions, such as cold environment and tape-stripping, indicated that increase in AQP3 expression appears to be involved in skin protection and showed that the pattern of AQP3 expression was more enhanced in the active ingredient-treated samples. In vivo confocal microscopy by Vivascope showed a generally healthier appearance of the skin in the treated areas. These results attest to the potential value of the active ingredient in optimizing environmental stress resistance and protecting the skin from stratum corneum damage.


Assuntos
Aquaporina 3/biossíntese , Queratinócitos/efeitos dos fármacos , Pele/efeitos dos fármacos , Aquaporina 3/genética , Células Cultivadas , Imunofluorescência , Humanos , Queratinócitos/citologia , Microscopia de Fluorescência , Pressão Osmótica , RNA Interferente Pequeno/genética , Pele/citologia
8.
Int J Cosmet Sci ; 33(5): 398-407, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21382056

RESUMO

The stem cell factor (SCF) and its protein-tyrosine kinase receptor KIT are together implicated in the regulation of diverse biological processes and particularly in melanogenesis. Indeed, this signalling pathway controls melanoblast migration from the neural crest during embryogenesis and allows the communication between keratinocytes and melanocytes in the adult. In melanocytes, the binding of SCF to its transmembrane receptor leads to the activation of signalling pathways implicating protein kinases which finally control the expression of pigmentation-related genes. We have developed a biological compound called IV09.007, which we previously described as a modulator of the SCF/KIT signalling pathway with a pro-pigmenting effect. In the present work, we have studied the expression and localization of both SCF and KIT mRNAs and proteins in the skin or skin-derived cell lines. Then, we explored with a microarray approach the ability of IV09.007 to modulate the expression of genes in human keratinocytes and melanocytes in culture. Thereby, we observed the regulation of genes implicated in DNA repair, mainly related to base/nucleotides excision pathways. A modulated transcriptional response was also observed for some genes implicated in the response against oxidative stress, in apoptosis inhibition and in lowering inflammatory immune response. These microarray results predicted a conferred protective effect of IV09.007 and we verified this hypothesis by performing comet assays on UVB-irradiated keratinocytes or melanocytes, to demonstrate the efficacy of IV09.007 on preventing DNA damage.


Assuntos
Dano ao DNA , Perfilação da Expressão Gênica , Queratinócitos/efeitos da radiação , Proteínas Proto-Oncogênicas c-kit/metabolismo , Transdução de Sinais , Fator de Células-Tronco/metabolismo , Raios Ultravioleta , Adulto , Linhagem Celular , Feminino , Humanos , Queratinócitos/metabolismo , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase em Tempo Real
9.
Ophthalmic Genet ; 42(6): 744-746, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34282983

RESUMO

INTRODUCTION: Cataract is a major condition characterized by ocular lens opacification, resulting from alteration in the lens architecture, lens proteins or both. It is responsible for about one-third of infants' blindness worldwide. Variants in the FYCO1 gene have been associated with autosomal recessive infantile cataract. MATERIAL AND METHODS: We conducted whole exome sequencing (WES) in a nine months old male patient who was referred for genetic investigation because of infantile cataract. WES analysis revealed the presence of a homozygous pathogenic variant (c.2365C>T) in exon 8 of the FYCO1 gene. RESULTS AND DISCUSSION: This is the first report on a Lebanese infant with infantile cataract and cortical atrophy which was not previously reported, resulting from a novel homozygous FYCO1 variant; thus expanding the clinical phenotypic spectrum of FYCO1 involvement.


Assuntos
Catarata/genética , Códon sem Sentido/genética , Córtex do Cristalino/patologia , Proteínas Associadas aos Microtúbulos/genética , Mutação , Atrofia , Catarata/congênito , Catarata/diagnóstico , Consanguinidade , Éxons/genética , Genes Recessivos , Homozigoto , Humanos , Lactente , Masculino , Linhagem , Reação em Cadeia da Polimerase , Sequenciamento do Exoma
10.
Clin Transl Oncol ; 23(11): 2302-2308, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33934271

RESUMO

BACKGROUND: This study aims to genomically characterize melanoma of unknown primary (MUP) in comparison to melanomas of cutaneous primary (MCP). METHODS: Eligible cases were collected from the MSK-IMPACT™ Clinical Sequencing Cohort published in the cBioPortal database. Genomic analysis was performed using a hybridization-capture-based next-generation sequencing assay designed to detect mutations, small insertions and deletions, copy number alterations, and genomic rearrangements. RESULTS: Among 462 patients of whom 18.4% had MUP, brain metastasis was more common among patients with MUP (23% vs 7.1%). The differences in genomic profiling between MCP and MUP did not reach statistical significance. The 187 MCP and 44 MUP patients treated with immune checkpoint inhibitors had a median overall survival of 49 and 44 months, respectively (p = 0.705). CONCLUSIONS: The differences in somatic mutation patterns and survival outcomes were not statistically significant. These findings may allude to similar carcinogenic processes but should be considered exploratory and interpreted with caution.


Assuntos
Melanoma/genética , Neoplasias Primárias Desconhecidas/genética , Neoplasias Cutâneas/genética , Neoplasias Encefálicas/secundário , Variações do Número de Cópias de DNA , Bases de Dados Genéticas , Feminino , Deleção de Genes , Rearranjo Gênico , Genes da Neurofibromatose 1 , Genes p53 , Perfil Genético , Genômica , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Neoplasias Pulmonares/secundário , Masculino , Melanoma/tratamento farmacológico , Melanoma/mortalidade , Melanoma/secundário , Mutação , Neoplasias Primárias Desconhecidas/tratamento farmacológico , Neoplasias Primárias Desconhecidas/mortalidade , Neoplasias Primárias Desconhecidas/patologia , Proteínas Tirosina Quinases/genética , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas B-raf/genética , Neoplasias Cutâneas/tratamento farmacológico , Neoplasias Cutâneas/mortalidade , Neoplasias Cutâneas/patologia , Telomerase/genética
12.
Int J Cosmet Sci ; 32(6): 446-57, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20572889

RESUMO

Researches on longevity and anti-ageing molecules have clearly evidenced the potential to increase lifespan of the cells. These recent scientific data raise interests and questions on the capacity of the cells to live longer and maintain their fundamental mechanisms of protection, reparation or degradation of abnormal proteins to maintain their capital of healthy and functional cellular activity. In this concern, this study was focused on the ubiquitin-proteasome system as an essential cellular tool to maintain the pool of functionally active proteins allowing renewal of proteins and degradation of damaged proteins. As the proteasome keeps the 'cells health capital', it should be particularly interesting to associate the maintenance of the proteasome activity with increasing longevity. Indeed, although oxidative stress damage increases with ageing leading to collagen and cellular membrane alterations, it also leads to a reduction in the proteasome activity which is critical for the cells. The aim of this study was to better understand the cellular role of the proteasome and to provide new data showing the skin beneficial effects in activating the overall system of ubiquitination and proteasomal degradation. For this purpose, in vitro, ex vivo and in vivo experiments were performed to evaluate the effects of maintaining the ubiquitin-proteasome activity in basal and stress conditions on young versus aged cells. Experiments have included evaluation of a newly developed dimerized tripeptide targeting specifically the ubiquitin-proteasome pathway. Our results have demonstrated that maintenance of this essential mechanism that participates in abnormal protein elimination and protein renewal allows maintaining cellular integrity that correlates with visible skin benefits.


Assuntos
Queratinócitos/metabolismo , Estresse Oxidativo/fisiologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Envelhecimento da Pele/fisiologia , Pele/metabolismo , Ubiquitina/metabolismo , Adulto , Biópsia , Método Duplo-Cego , Histocitoquímica , Humanos , Immunoblotting , Queratinócitos/citologia , Microscopia Confocal , Pessoa de Meia-Idade , Carbonilação Proteica/fisiologia , Pele/citologia , Perda Insensível de Água , Adulto Jovem
13.
Int J Cosmet Sci ; 32(2): 143-54, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20412219

RESUMO

Image processing steps and analysis techniques were developed for the quantification of photomicrographs obtained from light and fluorescence microscopy. The substrates examined were either skin cell cultures, such as normal human keratinocytes (NHK) or fibroblasts, or ex vivo skin sections. Examples of the analyses are provided for the comparison of skincare active ingredient treated samples vs. placebo to demonstrate the utility of the methods to quantify and provide numerical data for a procedure that is typically qualitative in nature and based on observations by a histologist. Quantifiable experiments that are discussed include: Fontana Masson staining for melanin expression; Nile red staining to detect cellular lipid droplets; nuclei staining with diamidino-phenylindole (DAPI); and immunofluorescent staining of protein expression with a primary antibody directed against the protein (antigen) and a secondary antibody tagged with a fluorescent dye (Alexa Fluor 488) against the primary antibody.


Assuntos
Cosméticos/farmacologia , Processamento de Imagem Assistida por Computador/métodos , Higiene da Pele/métodos , Pele/anatomia & histologia , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Humanos , Imuno-Histoquímica/métodos , Técnicas In Vitro , Queratinócitos/citologia , Queratinócitos/efeitos dos fármacos , Microscopia de Fluorescência/métodos , Pele/citologia , Pele/efeitos dos fármacos
14.
Eur J Med Genet ; 62(12): 103607, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30579973

RESUMO

Transcription Factor AP-2 Beta (TFAP2B) functions in the differentiation of neural crest cell derivatives and contributes to the embryogenesis of the ductus arteriosus. Mutations of TFAP2B produces Char syndrome. Char syndrome is an autosomal dominant disorder comprising facial dysmorphism, hand anomalies, and patent ductus arteriosus (PDA). In this report, we describe a proband with a de novo TFAP2B frameshift mutation c.650delG p.(Gly217Alafs*32) in the basic domain. The proband presented mainly with musculoskeletal features of Char syndrome. No PDA was identified at presentation suggesting that this syndrome may prove to be phenotypically heterogeneous. This report will help illustrate the genotype/phenotype correlation of TAFB2 mutations and better delineate the clinical features in Char syndrome.


Assuntos
Anormalidades Múltiplas/genética , Permeabilidade do Canal Arterial/genética , Face/anormalidades , Dedos/anormalidades , Fenótipo , Fator de Transcrição AP-2/genética , Anormalidades Múltiplas/patologia , Permeabilidade do Canal Arterial/patologia , Face/patologia , Dedos/patologia , Humanos , Lactente , Masculino , Mutação
15.
Drugs Exp Clin Res ; 31(3): 89-99, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16033247

RESUMO

Recently, it has become indispensable for anti-aging active ingredients to provide a visible and immediate smoothing antiwrinkle effect. In Quercus suber, suberin is the most important structural component of cork cell walls. Studies have shown that suberin is made up mostly of hydroxycarboxylic acids and that it is endowed with many special mechanical and chemical properties that evoke a possible smoothing effect on the surface of the skin. Therefore, we were interested in investigating the effect of this cork extract on the skin's surface in a double-blind clinical study. The study was conducted in 15 healthy volunteers, aged 22 to 52 years. The volunteers applied a gel formula with 3% of cork extract, or placebo gel, on each forearm. Skin surface roughness was evaluated visually by pictures and by silicone replicas 1 and 2 h after application, followed by statistical analysis using the matched-pairs McNemar statistical test. McNemar analysis of the pictures revealed that application of cork extract on the skin resulted in a highly significant reduction of roughness 1 h after application. This effect was observed in 73.3% of volunteers. Two hours after cork extract application, a highly significant improvement of skin roughness was found in 78.6% of volunteers. Moreover, silicone replica treatment confirmed significant improvement in average of roughness at 2 h. These results demonstrate that cork extract provides a remarkable and highly significant tensor and smoothing effect on the skin, which could be of great use in anti-aging skin care products.


Assuntos
Lipídeos de Membrana/uso terapêutico , Quercus/química , Envelhecimento da Pele/efeitos dos fármacos , Pele/efeitos dos fármacos , Administração Cutânea , Adulto , Método Duplo-Cego , Feminino , Humanos , Lipídeos , Masculino , Lipídeos de Membrana/administração & dosagem , Pessoa de Meia-Idade , Extratos Vegetais/administração & dosagem , Extratos Vegetais/uso terapêutico , Estruturas Vegetais/química
16.
Drugs Exp Clin Res ; 31(4): 131-40, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16223202

RESUMO

Cotton honeydew extract is composed of a unique combination of oligosaccharides, including fructose, glucose, inositol, melezitose, saccharose, trehalose and trehalulose. Studies have shown that these oligosaccharides exhibit a protective effect. Therefore, we were interested in studying the effect of these oligosaccharides on normal and damaged human hair. Both clinical and scanning electron microscopy (SEM) studies were performed. Standardized human hair samples were used to determine the effect of a rinse-off mask with 1% cotton honeydew extract on the ultrastructure of hair. In addition, hair samples were submitted to different aggressions, following various experimental protocols. SEM showed that, without extra aggression, the cuticle scales appeared to lie more smoothly in the hair in cotton honeydew extract-treated samples than in untreated samples. The extract-treated hair samples were also less prone to chipping. In contrast, the control, untreated hair samples retained a dry and damaged appearance and were prone to chipping and progressive splitting. In a clinical study, 15 volunteers had half of their hair treated with a formula with 1% honeydew extract and the other half was left untreated as a control. Pictures and visual evaluation of the hair showed that the honeydew extract formula left the hair with a smoothness that was far superior to the control side and this result was confirmed by SEM. In addition, mRNA studies on epidermal cells were performed and confirmed the stimulating effect of honeydew extract on keratin synthesis. These results demonstrate that cotton honeydew extract can be of great use in hair care products and cosmetics.


Assuntos
Cosméticos , Gossypium/química , Preparações para Cabelo , Extratos Vegetais/farmacologia , Adulto , Linhagem Celular , Feminino , Cabelo/ultraestrutura , Humanos , Queratinas/biossíntese , Queratinas/genética , Microscopia Eletrônica de Varredura , Pessoa de Meia-Idade , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
17.
Endocrinology ; 141(1): 354-65, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10614658

RESUMO

Internalization of G protein-coupled receptors is crucial for resensitization of phosphorylation-desensitized receptors, but also for their long term desensitization through sequestration. To elucidate the mechanisms regulating cell surface availability of the somatostatin (SRIF) receptor subtype sst5, we characterized its internalization properties in transfected COS-7 cells using biochemical, confocal microscopic, and electron microscopic techniques. Our results demonstrated rapid and efficient sequestration of specifically bound [125I]Tyr0-D-Trp8-SRIF (up to 45% of bound radioactivity). Combined immunocytochemical detection of sst5 and visualization of a fluorescent SRIF analog by confocal microscopy revealed that whereas the internalized ligand progressively clustered toward the cell center with time, immunoreactive receptors remained predominantly associated with the plasma membrane. The preservation of cell surface receptors was confirmed by binding experiments on whole cells revealing a lack of saturability of [125I]Tyr0-D-Trp8-SRIF binding at 37 C. Binding was rendered saturable by the drug monensin, showing that receptor recycling played a key role in the preservation of cell surface receptors. Electron microscopy demonstrated that in addition to receptor recycling, internalization of receptor-ligand complexes triggered a massive recruitment of sst5 receptor molecules from intracellular stores to the membrane. This combination of recycling and recruitment of spare receptors may protect sst5 from long term down-regulation through sequestration and, therefore, facilitate extended SRIF signaling.


Assuntos
Endocitose/fisiologia , Receptores de Somatostatina/metabolismo , Transfecção/genética , Animais , Células COS , Membrana Celular/metabolismo , Membrana Celular/ultraestrutura , Endocitose/efeitos dos fármacos , Endocitose/genética , Cinética , Ligantes , Microscopia Confocal , Microscopia Eletrônica , Somatostatina/análogos & derivados , Somatostatina/metabolismo
18.
Peptides ; 21(4): 577-87, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10822115

RESUMO

The preparation of a pure 125I-labeled monoiododerivative of mouse leptin is described. This radiolabeled analog has been used to characterize and localize central and peripheral leptin binding sites (Ob-R) of the mouse at different stages of its development. The affinity values found in membrane homogenates of various mouse tissues are similar and range between 0.1 and 0.3 nM, indicating that all the Ob-R isoforms have a similar affinity. Leptin binding sites are highly expressed at the membrane level in lung, intestine, kidney, liver, and skin and to a lesser degree in stomach, heart, and spleen. Brain, thymus, and pancreas homogenates are devoid of any specific binding. The distribution of mouse Ob-R has also been explored by autoradiography and dipping techniques on whole mouse sections. In lung, leptin binding sites are located at the pulmonary parenchyma and at the bronchiolar epithelial level. Binding sites are expressed all along the digestive tract from the tongue to the rectum (esophagus, stomach, intestine, colon, and rectum). In muscular visceral structures (stomach, intestine, and bladder) the binding is mainly present in the lamina propria. During development, leptin receptors are early expressed in the liver, kidney, and bone. In the lung, the Ob-R level increased gradually from birth to adulthood where the expression is maximal. By contrast, leptin receptors located in the medulla of the kidney remain remarkably constant all along the development. A broad signal is present in cartilage and bone particularly in vertebrae, limb, and ribs. Interestingly, leptin receptors are barely detectable in the mouse brain except in the choroid plexus and leptomeninges, whereas in the rat brain leptin binding sites are located in the thalamus, the piriform cortex, the cerebellum (at the granular and molecular cell layer), and the pineal gland.


Assuntos
Proteínas de Transporte/metabolismo , Leptina/metabolismo , Receptores de Superfície Celular , Animais , Animais Recém-Nascidos , Autorradiografia , Sítios de Ligação , Encéfalo/embriologia , Encéfalo/crescimento & desenvolvimento , Encéfalo/metabolismo , Cromatografia Líquida de Alta Pressão , Embrião de Mamíferos , Humanos , Radioisótopos do Iodo , Ligantes , Pulmão/embriologia , Pulmão/crescimento & desenvolvimento , Pulmão/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Obesidade/metabolismo , Especificidade de Órgãos , Ensaio Radioligante , Ratos , Ratos Wistar , Receptores para Leptina , Proteínas Recombinantes/metabolismo
19.
Cancer Genet Cytogenet ; 155(2): 138-42, 2004 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15571799

RESUMO

Variants of the t(8;21)(q22;q22) involving chromosomes 8, 21, and other chromosomes account for approximately 3% of all t(8;21)(q22;q22) in acute myeloid leukemia (AML) patients. In this paper, we report a case of AML-M2 with a t(8;12;21)(q22;p12 approximately p13;q22) associated with chromosomal abnormalities, including loss of the Y chromosome and trisomy 8q22 approximately qter. Using a dual-color fluorescence in situ hybridization (FISH) analysis with ETO and AML1 probes, we demonstrated an ETO/AML1 fusion signal on the derivative chromosome 8. Using whole painting probes for chromosomes 8 and 12, we demonstrated a three-way translocation, t(8;12;21)(q22;p12 approximately p13;q22). Reverse transcription polymerase chain reaction (RT-PCR) analysis showed the presence of AML1/ETO fusion transcript. The present case highlights the importance of the combination of approaches, i.e., standard karyotyping, FISH, and RT-PCR, for the detection of variants of t(8;21)(q22;q22), shedding light on region 8q22 approximately qter which could harbor potential genes responsible for leukemogenesis.


Assuntos
Cromossomos Humanos Par 12 , Cromossomos Humanos Par 21 , Cromossomos Humanos Par 8 , Variação Genética , Leucemia Mieloide Aguda/genética , Translocação Genética , Adulto , Idade de Início , Medula Óssea/patologia , Códon de Terminação , Subunidade alfa 2 de Fator de Ligação ao Core , Sondas de DNA , Eletroforese em Gel de Ágar , Humanos , Imunofenotipagem , Hibridização in Situ Fluorescente , Cariotipagem , Proteínas de Fusão Oncogênica/genética , Proteína 1 Parceira de Translocação de RUNX1 , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Transcrição/genética , Trissomia/diagnóstico , Trissomia/genética
20.
Braz J Med Biol Res ; 31(11): 1479-89, 1998 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9921286

RESUMO

This paper reviews the use of confocal microscopy as it pertains to the identification of G-protein coupled receptors and the study of their dynamic properties in cell cultures and in mammalian brain following their tagging with specific fluorescent ligands. Principles that should guide the choice of suitable ligands and fluorophores are discussed. Examples are provided from the work carried out in the authors' laboratory using custom synthetized fluoresceinylated or BODIPY-tagged bioactive peptides. The results show that confocal microscopic detection of specifically bound fluorescent ligands permits high resolution appraisal of neuropeptide receptor distribution both in cell culture and in brain sections. Within the framework of time course experiments, it also allows for a dynamic assessment of the internalization and subsequent intracellular trafficking of bound fluorescent molecules. Thus, it was found that neurotensin, somatostatin and mu- and delta-selective opioid peptides are internalized in a receptor-dependent fashion and according to receptor-specific patterns into their target cells. In the case of neurotensin, this internalization process was found to be clathrin-mediated, to proceed through classical endosomal pathways and, in neurons, to result in a mobilization of newly formed endosomes from neural processes to nerve cell bodies and from the periphery of cell bodies towards the perinuclear zone. These mechanisms are likely to play an important role for ligand inactivation, receptor regulation and perhaps also transmembrane signaling.


Assuntos
Receptores de Neuropeptídeos/metabolismo , Endocitose , Fluorescência , Proteínas de Ligação ao GTP , Ligantes , Microscopia Confocal , Entorpecentes/metabolismo , Neurotensina/metabolismo , Peptídeos , Ligação Proteica , Somatostatina/metabolismo
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