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1.
Klin Onkol ; 37(6): 462-466, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38158235

RESUMO

BACKGROUND: Breast cancer is recognized as a major clinical challenge in gynecological diseases worldwide. Exosomes are small vesicles derived from multicellular bodies that are secreted by many cells into the extracellular environment and thus participate in intercellular communication through the transfer of genetic information such as encoded and non-encoded RNAs to target cells. Tumor-derived exosomes are thought to be a rich source of microRNAs (miRNAs) that can regulate the function of other cancer cells in the tumor microenvironment. However, the exact mechanisms by which tumor cell-derived exosomes affect their neighboring cells, as well as the biological function of exosomal miRNAs in receptor cells, are not well understood. MATERIALS AND METHODS: In this study, after overexpression of miR-205 in breast cancer cells (MDA-MB-231 class), cell-derived exosomes were successfully isolated and characterized by electron microscopy and dynamic light scattering. RESULTS: Determination of miR-205 expression levels in exosomes secreted from engineered cells confirmed the high expression of this miRNA in exosomes. It was also found that treatment of tumor exosomes carrying this miRNA had an apoptotic induction effect and also had a significant effect on reducing the expression of Bcl-2 gene transcript in a time-dependent manner in breast cancer cells (P < 0.001). CONCLUSION: Overall, this study suggests that exosomal transfer of tumor suppressor miRNAs to cancer cells could be a suitable platform for nucleic acid transfer to these cells and be highly effective in cancer treatment.


Assuntos
Neoplasias da Mama , Exossomos , MicroRNAs , Humanos , Feminino , Neoplasias da Mama/patologia , Exossomos/genética , Linhagem Celular Tumoral , MicroRNAs/genética , MicroRNAs/metabolismo , Microambiente Tumoral
2.
J Med Case Rep ; 15(1): 488, 2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-34602094

RESUMO

BACKGROUND: Melkersson-Rosenthal syndrome is a rare disease characterized by the triad of recurrent orofacial swelling with facial paralysis and fissured dorsal tongue. Histologically, noncaseating granulomatous inflammation occurs that confirms the diagnosis. Overlaps between granulomatous diseases such as sarcoidosis and Crohn's disease are described. Systemic corticosteroid therapy is the treatment of choice for acute attacks. CASE PRESENTATION: We here present a case of a 59-year-old White woman suffering from Melkersson-Rosenthal syndrome with a past history of sarcoidosis on therapy with leflunomide in combination with low-dose tacrolimus successfully treated with the anti-leprosy drug clofazimine after failure of systemic steroid therapy. CONCLUSIONS: We propose clofazimine as an alternative treatment in steroid-refractory cases.


Assuntos
Doença de Crohn , Paralisia Facial , Síndrome de Melkersson-Rosenthal , Sarcoidose , Terapia Comportamental , Feminino , Humanos , Síndrome de Melkersson-Rosenthal/complicações , Síndrome de Melkersson-Rosenthal/diagnóstico , Síndrome de Melkersson-Rosenthal/tratamento farmacológico , Pessoa de Meia-Idade , Sarcoidose/complicações , Sarcoidose/diagnóstico , Sarcoidose/tratamento farmacológico
3.
J Chem Phys ; 151(11): 114907, 2019 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-31542012

RESUMO

Janus particles interfacially self-assemble into different structures when incorporated into multiphase systems. Dissipative particle dynamics simulations are employed herein to investigate the interplay between aggregation mechanisms and phase separation in polymer blends. Shorter rods with a standing configuration become increasingly "caged" or trapped in larger aggregates as weight fraction increases, which is reflected in the way that their diffusion is coupled to their aggregation rates. Janus rods of higher aspect ratios that are tilted at the interface aggregate side-by-side and are able to hinder phase separation kinetics. This is due to a combination of individual Janus rod conformations at the interface, their intrinsic aggregation mechanisms, aggregate fractal dimension, and aggregation rates, and can also be traced back to the scaling of the diffusion coefficient of aggregates with their size. Findings presented provide insight into the mechanisms governing two dimensionally growing colloidal aggregates at fluid interfaces, more specifically, those associated with Janus particles, and shed light on the potential of these systems in paving the way for designing new functional materials.

5.
Climacteric ; 20(1): 67-71, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28064523

RESUMO

OBJECTIVES: Our aim was to explore the experiences of Iranian postmenopausal women who sought medical help for their symptomatic vulvovaginal atrophy (VVA). METHODS: Five focus group discussions (FGDs) were conducted. Participants had to be postmenopausal; had bothersome symptoms of VVA for which they came to the clinic; had previously sought medical help for their VVA; and had confirmed physical signs of VVA upon examination by a gynecologist. RESULTS: Twenty-five women, aged 49-60 years participated in the five FGDs. Twenty women said they currently had >1 VVA symptom at presentation to the clinic. Four major themes emerged from the women's narrative stories: (1) negative impact of VVA on women's life, (2) psychological distress associated with VVA, (3) negative impact of VVA on marriage and relationship, (4) inadequate symptom relief from available treatments due to lack of awareness of VVA treatment options. None of the participants reported ongoing treatment of their VVA with local low-dose estrogen. Women further commented that, although local estrogen products were costly, they would like to use them if they were prescribed. CONCLUSIONS: Considering the negative impact of VVA symptoms on women's lives, health professionals in Iran should be prescribing approved and effective therapies for symptomatic women.


Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Pós-Menopausa , Vagina/patologia , Vulva/patologia , Atrofia/tratamento farmacológico , Atrofia/psicologia , Estrogênios/uso terapêutico , Feminino , Grupos Focais , Humanos , Irã (Geográfico) , Pessoa de Meia-Idade , Qualidade de Vida , Comportamento Sexual/psicologia , Estresse Psicológico/etiologia
6.
Artigo em Inglês | LILACS-Express | LILACS, VETINDEX | ID: biblio-1467334

RESUMO

Abstract Due to increased number of herbicide resistant weeds, it is needed to explore the allelopathic potential of plants as an alternative. The research was conducted to investigate allelopathic effects of Carica papaya L. leaf powder and aqueous extract on seeds as well as pre-germinated seeds of Avena fatua L., Helianthus annuus L., Rumex dentatus L., Zea mays L. and Triticum aestivum L. on filter paper and soil in Weed Management Program Laboratory, Department of Plant and Environmental Protection at PARC Institute of Advanced Studies in Agriculture, National Agriculture Research Centre, Islamabad, Pakistan. Germination percentage (%), radicle length (cm) and plumule length (cm) were parameters observed for Plant leaf powder bioassay and Aqueous extract method. Most significant growth inhibition was observed in A. fatua seedlings in filter paper method. A. fatua radicle length was reduced by C. papaya aqueous extract (80%) and leaf powder (89%) bioassays. Plumule length was reduced under the influence of aqueous extract (57-73%) and powdered material (59-77%). The inhibitory effects on other test species were in sequence of H. annuus followed by Z. mays and R. dentatus. The aqueous extract showed non-significant effect on wheat seed germination, radicle and plumule growth. It is suggested that C. papaya aqueous extract can be used as source of weed management in wheat crop.


Resumo Devido ao aumento do número de ervas daninhas resistentes aos herbicidas, é necessário explorar o potencial alelopático das plantas como uma alternativa. A pesquisa foi conduzida com o objetivo de investigar os efeitos alelopáticos do pó foliar de Carica papaya e do extrato aquoso das sementes, bem como das sementes pré-germinadas de Avena fatua, Helianthus annuus, Rumex dentatus, Zea mays e Triticum aestivum em papel de filtro e solo no Laboratório do Programa de Manejo de Ervas Daninhas, Departamento de Plantas e Proteção Ambiental do Instituto PARC de Estudos Avançados em Agricultura, Centro Nacional de Pesquisa Agrícola, Islamabad, Paquistão. A porcentagem de germinação (%), o comprimento radicular e o comprimento da plúmula (cm) foram os parâmetros observados para o 'Bioensaio de Pó de Folha de Planta' e o 'Método de Extração Aquoso'. A maior inibição do crescimento foi observada em mudas de A. fatua no método de papel de filtro. O comprimento radicular de A. fatua foi reduzido com os extratos aquosos de C. papaya (80%) e pó de folhas (89%). O comprimento das plúmulas foi reduzido sob a influência do extrato aquoso (57-73%) e material em pó (59-77%). Os efeitos inibitórios em outras espécies-teste foram na sequência de H. annuus seguido por Z. mays e R. dentatus. O extrato aquoso apresentou efeito não significativo na germinação das sementes de trigo, nos crescimentos radiculares e das plúmulas. Sugere-se que o extrato aquoso de C. papaya pode ser utilizado como fonte de manejo de plantas daninhas na cultura do trigo.

7.
Gene Ther ; 23(2): 196-204, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26348595

RESUMO

The X-linked RP3 gene codes for the ciliary protein RPGR and accounts for over 10% of inherited retinal degenerations. The critical RPGR-ORF15 splice variant contains a highly repetitive purine-rich linker region that renders it unstable and difficult to adapt for gene therapy. To test the hypothesis that the precise length of the linker region is not critical for function, we evaluated whether adeno-associated virus-mediated replacement gene therapy with a human ORF15 variant containing in-frame shortening of the linker region could reconstitute RPGR function in vivo. We delivered human RPGR-ORF15 replacement genes with deletion of most (314 codons, 'short form') or 1/3 (126 codons, 'long form') of the linker region to Rpgr null mice. Human RPGR-ORF15 expression was detected post treatment with both forms of ORF15 transgenes. However, only the long form correctly localized to the connecting cilia and led to significant functional and morphological rescue of rods and cones. Thus the highly repetitive region of RPGR is functionally important but that moderate shortening of its length, which confers the advantage of added stability, preserves its function. These findings provide a theoretical basis for optimizing replacement gene design in clinical trials for X-linked RP3.


Assuntos
Dependovirus/genética , Proteínas do Olho/genética , Terapia Genética , Retinose Pigmentar/terapia , Processamento Alternativo , Animais , Modelos Animais de Doenças , Receptor Quinase 1 Acoplada a Proteína G/genética , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Regiões Promotoras Genéticas , Células Fotorreceptoras Retinianas Cones/fisiologia , Células Fotorreceptoras Retinianas Bastonetes/fisiologia , Retinose Pigmentar/genética
8.
East Mediterr Health J ; 21(1): 29-38, 2015 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-25907190

RESUMO

No tools to assess women's general sexual and reproductive health needs have been validated in the Iranian context. This study in Sari in Mazandaran province of the Islamic Republic of Iran was conducted to evaluate the psychometric properties of a Persian version of the Sexual and Reproductive Health Needs Assessment Questionnaire (first developed for the International Organization for Migration and United Nations Population Fund). The Persian version of the questionnaire was found to have adequate face and content validity (quantitative and qualitative) for assessing sexual and reproductive health needs among women (content validity index = 0.88). The test-retest reliability showed that, except for the domain of sexually transmitted infections, all domains of the questionnaire had an acceptable reliability (intra-class correlation coefficients > 0.5). This questionnaire is a valid tool for assessing the sexual and reproductive health needs of Iranian women and planning/designing strategies to meet them.


Assuntos
Avaliação das Necessidades/organização & administração , Serviços de Saúde Reprodutiva/organização & administração , Saúde da Mulher , Adolescente , Adulto , Feminino , Humanos , Irã (Geográfico) , Pessoa de Meia-Idade , Psicometria , Reprodutibilidade dos Testes , Comportamento Sexual , Infecções Sexualmente Transmissíveis/epidemiologia , Fatores Socioeconômicos , Maus-Tratos Conjugais/psicologia , Inquéritos e Questionários
9.
Clin Exp Dermatol ; 40(3): 324-30, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25476471

RESUMO

BACKGROUND: Bullous pemphigoid (BP) is a subepidermal blistering disease, characterized by autoantibodies directed against BP180 and BP230. Collecting saliva is an easy and painless way of obtaining biological samples, and can be used for diagnosis of autoimmune diseases. AIM: To compare the diagnostic accuracy of serum and salivary BP180-NC16a and BP230-C3 in the initial diagnosis of BP. METHODS: We assessed 50 patients newly diagnosed with BP and 50 healthy controls. The diagnosis of BP was confirmed based on clinical, histopathological and immunofluorescence findings. Serum and saliva samples were collected from both groups, and BP180 and BP230 titres were assessed using commercially available ELISA kits. RESULTS: Using serum, the sensitivity of the serum BP180 and BP230 ELISA assays was 88% and 48%, respectively, and the specificity of both was 96%. Using saliva with the cutoff value proposed by the manufacturer, sensitivity was 56.2% and 14.6%, and specificity was 98% and 100%, respectively. Using the best calculated cutoff for saliva, sensitivity increased to 87.5% and 77.1%, and specificity to 96% and 62%, respectively. There was a significant correlation between serum and saliva BP180 levels and the severity of skin disease. Both serum and saliva BP230 levels were significantly higher in patients with mucosal involvement. CONCLUSION: Serum BP180 NC16a ELISA is a sensitive and specific test for the initial diagnosis of BP, whereas serum BP230-C3 ELISA is highly specific, but less sensitive. Saliva may be a noninvasive and convenient alternative for use in the BP180 NC16a ELISA to diagnose BP.


Assuntos
Autoantígenos/análise , Proteínas de Transporte/análise , Proteínas do Citoesqueleto/análise , Proteínas do Tecido Nervoso/análise , Colágenos não Fibrilares/análise , Penfigoide Bolhoso/diagnóstico , Adulto , Idoso , Idoso de 80 Anos ou mais , Autoantígenos/sangue , Biomarcadores/análise , Biomarcadores/sangue , Proteínas de Transporte/sangue , Estudos de Casos e Controles , Proteínas do Citoesqueleto/sangue , Distonina , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas do Tecido Nervoso/sangue , Colágenos não Fibrilares/sangue , Penfigoide Bolhoso/imunologia , Análise de Regressão , Saliva/química , Sensibilidade e Especificidade , Colágeno Tipo XVII
10.
J Mech Behav Biomed Mater ; 4(7): 1123-31, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21783121

RESUMO

In this investigation, semiempirical and numerical studies of blood flow in a viscoelastic artery were performed using the Cosserat continuum model. The large-amplitude oscillatory shear deformation model was used to quantify the nonlinear viscoelastic response of blood flow. The finite difference method was used to solve the governing equations, and the particle swarm optimization algorithm was utilized to identify the non-Newtonian coefficients (k(υ) and γ(υ)). The numerical results agreed well with previous experimental results.


Assuntos
Artérias/fisiologia , Circulação Sanguínea , Elasticidade , Modelos Biológicos , Resistência ao Cisalhamento , Algoritmos , Fenômenos Biomecânicos , Humanos , Hidrodinâmica , Rotação , Viscosidade
11.
Eur J Med Res ; 15(11): 504-6, 2010 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-21159575

RESUMO

Cryptococcus neoformans is the most common cause of life threatening meningoencephalitis in HIV-infected patients. Diagnosis is based on tests for cryptoccocal antigen in serum and cerebrospinal fluid, and on culture of the organism. We present a case of AIDS-related cryptococcal meningoencephalitis unresponsive to antifungal combination therapy, despite of evidence of fungal susceptibility in vitro. Significant decreases in cryptococcal antigen titers in serum and cerebrospinal fluid did not correlate with progress in disease and fatal outcome.


Assuntos
Infecções Oportunistas Relacionadas com a AIDS/tratamento farmacológico , Antifúngicos/uso terapêutico , Meningite Criptocócica/tratamento farmacológico , Infecções Oportunistas Relacionadas com a AIDS/líquido cefalorraquidiano , Adulto , Evolução Fatal , Humanos , Masculino , Meningite Criptocócica/líquido cefalorraquidiano
12.
Pak J Biol Sci ; 13(7): 335-9, 2010 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-20836289

RESUMO

The aim of this study was to evaluate the relationship between maternal serum magnesium levels and preterm birth. This Nested case-control study carried out on 20 with preterm birth and 20 women at term birth at Imam Khomeini Hospital in Sari/Iran in 2008. The women with singleton gestation and intact fetal membrane suspected to preterm labor (case group), 10 cc blood samples were drawn into syringes and sent to laboratory of the hospital immediately. Sampling for control group was same as the case group. These samples recognized as control group just as birth occurring after week 37. Finally, serum magnesium level measured. Data analyzed using chi2, t-test and OR (Odd's Ratio). There was a relationship between the number of prenatal visits (p = 0.008) and stressful events associated with preterm birth (p < 0.02). Serum magnesium level was associated with preterm birth OR = 4.75, CI 95% = (0.48-46.91), Sensitivity, specificity, positive and negative predictive value of serum magnesium for preterm birth was 95, 50, 66.5 and 83.33%, respectively. Although, there was a correlation between serum magnesium levels and preterm birth, due to methodology of the study, a cohort study with the same cut off point and supplementation of magnesium in RTC studies is recommended.


Assuntos
Magnésio/sangue , Trabalho de Parto Prematuro/sangue , Nascimento Prematuro/sangue , Adulto , Estudos de Casos e Controles , Feminino , Idade Gestacional , Humanos , Irã (Geográfico) , Razão de Chances , Gravidez , Curva ROC , Sensibilidade e Especificidade , Adulto Jovem
13.
Gene Ther ; 17(1): 117-31, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19710705

RESUMO

Aryl hydrocarbon receptor-interacting protein-like 1 (AIPL1) is required for the biosynthesis of photoreceptor phosphodiesterase (PDE). Gene defects in AIPL1 cause a heterogeneous set of conditions ranging from Leber's congenital amaurosis (LCA), the severest form of early-onset retinal degeneration, to milder forms such as retinitis pigmentosa (RP) and cone-rod dystrophy. In mice, null and hypomorphic alleles cause retinal degeneration similar to human LCA and RP, respectively. Thus these mouse models represent two ends of the disease spectrum associated with AIPL1 gene defects in humans. We evaluated whether adeno-associated virus (AAV)-mediated gene replacement therapy in these models could restore PDE biosynthesis in rods and cones and thereby improve photoreceptor survival. We validated the efficacy of human AIPL1 (isoform 1) replacement gene controlled by a promoter derived from the human rhodopsin kinase (RK) gene, which is active in both rods and cones. We found substantial and long-term rescue of the disease phenotype as a result of transgene expression. This is the first gene therapy study in which both rods and cones were targeted successfully with a single photoreceptor-specific promoter. We propose that the vector and construct design used in this study could serve as a prototype for a human clinical trial.


Assuntos
Proteínas de Transporte/genética , Receptor Quinase 1 Acoplada a Proteína G/genética , Terapia Genética , Atrofia Óptica Hereditária de Leber/terapia , Degeneração Retiniana/terapia , Células Fotorreceptoras Retinianas Bastonetes/metabolismo , Proteínas Adaptadoras de Transdução de Sinal , Animais , Proteínas do Olho , Técnicas de Transferência de Genes , Humanos , Camundongos , Diester Fosfórico Hidrolases/metabolismo , Células Fotorreceptoras Retinianas Cones/metabolismo
14.
Clin Sci (Lond) ; 101(6): 739-47, 2001 12.
Artigo em Inglês | MEDLINE | ID: mdl-11724664

RESUMO

Android obesity is associated with increased cortisol secretion. Direct effects of cortisol on gluconeogenesis and other parameters of insulin resistance were determined in normal subjects. Gluconeogenesis was determined using the reciprocal pool model of Haymond and Sunehag (HS method), and by the Cori cycle/lactate dilution method of Tayek and Katz (TK method). Glucose production (GP) and gluconeogenesis were measured after a 3 h baseline infusion and after a 4-8 h pituitary-pancreatic infusion of somatostatin, replacement insulin, growth hormone (GH), glucagon and a high dose of cortisol (hydrocortisone). The pituitary-pancreatic infusion maintains insulin, GH and glucagon concentrations within the fasting range, while increasing the concentration of only one hormone, cortisol. Two groups of five subjects were each given high-dose cortisol administration, and results were compared with those from a group of six 'fasting alone' subjects (no infusion) at 16 and 20 h of fasting. Fasting GP (12 h fasting) was similar in all groups, averaging 12.5+/-0.2 micromol x min(-1) x kg(-1). Gluconeogenesis, as a percentage of GP, was 35+/-2% using the HS method and 40+/-2% using the TK method. After 16 h of fasting, GP had fallen (11.5+/-0.6 micromol x min(-1) x kg(-1)) and gluconeogenesis had increased (55+/-5% and 57+/-5% of GP by the HS and TK methods respectively; P<0.05). High-dose cortisol infusion for 4 h increased serum cortisol (660+/-30 nmol/l; P<0.05), blood glucose (7.9+/-0.5 mmol/l; P<0.05) and GP (14.8+/-0.8 micromol x min(-1) x kg(-1); P<0.05). The increase in GP was due entirely to an increase in gluconeogenesis, determined by either the HS or the TK method (66+/-6% and 65+/-5% of GP respectively; P<0.05). Thus cortisol administration in humans increases GP by stimulating gluconeogenesis. Smaller increases in serum cortisol may contribute to the abnormal glucose metabolism known to occur in the metabolic syndrome.


Assuntos
Gluconeogênese/efeitos dos fármacos , Hidrocortisona/farmacologia , Obesidade/fisiopatologia , Adulto , Aminoácidos/sangue , Glicemia/efeitos dos fármacos , Glicemia/metabolismo , Jejum/sangue , Ácidos Graxos não Esterificados/sangue , Glucose/biossíntese , Humanos , Pessoa de Meia-Idade , Obesidade/sangue , Síndrome
15.
Mol Vis ; 5: 41, 1999 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-10617778

RESUMO

PURPOSE: Patients with fundus albipunctatus uniformly experience difficulty with vision at night. Their retinas are spotted with characteristic light yellow flecks of unknown composition that typically spare the macula. A defect in the transport or utilization of visual cycle retinoids is thought to underlie this recessive disorder with variable clinical expression. To elucidate the molecular defect we considered the genes for interphotoreceptor retinoid-binding protein (RBP3) and 11-cis retinol dehydrogenase (RDH5) as candidates for this disease. METHODS: We examined two unrelated families with fundus albipunctatus. The diagnosis was determined clinically and RBP3 and RDH5 were analyzed by molecular screening methods and direct genomic sequencing. RESULTS: Each family had two affected members with typical fundus albipunctatus. The affected members were siblings born to unaffected parents who were seventh cousins in the first family and unrelated in the second family. The probands from both families were clinically similar except for the fundus dots that were more extensive in the second family to the point of involving the parafoveal region. In the initial phase of genetic screening RBP3 defects were ruled-out as the cause of the disease in both families. In contrast, RDH5 mutations were found in the affected siblings in both families. The proband in one had a homozygotic Gly238Trp missense mutation (GGG -> TGG) involving exon 4 and in the other carried compound heterozygotic changes Arg280His (CGC -> CAC) and Ala294Pro (GCC -> CCC) in exon 5. The disease phenotype was only manifested in family members with two abnormal RDH5 alleles consistent with autosomal recessive inheritance in both pedigrees. CONCLUSIONS: These findings strongly implicate defects of RDH5 as the cause of fundus albipunctatus and point to a heterogeneity of RDH5 mutations in this form of congenital stationary night blindness with variable expressivity.


Assuntos
Oxirredutases do Álcool/genética , Oftalmopatias Hereditárias/genética , Proteínas do Olho , Cegueira Noturna/genética , Doenças Retinianas/genética , Proteínas de Ligação ao Retinol/genética , Adulto , Sequência de Bases , DNA/química , Feminino , Humanos , Masculino , Mutação , Cegueira Noturna/congênito , Linhagem , Reação em Cadeia da Polimerase , Polimorfismo Conformacional de Fita Simples , Doenças Retinianas/congênito
16.
Proc Natl Acad Sci U S A ; 95(6): 2824-7, 1998 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-9501174

RESUMO

Rhodopsin kinase (RK), a rod photoreceptor cytosolic enzyme, plays a key role in the normal deactivation and recovery of the photoreceptor after exposure to light. To date, three different mutations in the RK locus have been associated with Oguchi disease, an autosomal recessive form of stationary night blindness in man characterized in part by delayed photoreceptor recovery [Yamamoto, S. , Sippel, K. C., Berson, E. L. & Dryja, T. P. (1997) Nat. Genet. 15, 175-178]. Two of the mutations involve exon 5, and the remaining mutation occurs in exon 7. Known exon 5 mutations include the deletion of the entire exon sequence [HRK(X5 del)] and a missense change leading to a Val380Asp substitution in the encoded product (HRKV380D). The mutation in exon 7 is a 4-bp deletion in codon 536 leading to premature termination of the encoded polypeptide [HRKS536(4-bp del)]. To provide biochemical evidence for pathogenicity of these mutations, wild-type human rhodopsin kinase (HRK) and mutant forms HRKV380D and HRKS536(4-bp del) were expressed in COS7 cells and their activities were compared. Wild-type HRK catalyzed light-dependent phosphorylation of rhodopsin efficiently. In contrast, both mutant proteins were markedly deficient in catalytic activity with HRKV380D showing virtually no detectible activity and HRKS536(4-bp del) only minimal light-dependent activity. These results provide biochemical evidence to support the pathogenicity of the RK mutations in man.


Assuntos
Proteínas do Olho , Mutação , Cegueira Noturna/congênito , Proteínas Quinases/genética , Sequência de Aminoácidos , Animais , Células COS , Receptor Quinase 1 Acoplada a Proteína G , Humanos , Luz , Dados de Sequência Molecular , Cegueira Noturna/etiologia , Cegueira Noturna/genética , Fosforilação/efeitos da radiação , Proteínas Quinases/metabolismo , Proteínas Recombinantes/metabolismo , Rodopsina/metabolismo , Homologia de Sequência de Aminoácidos
17.
J Biol Chem ; 273(9): 5124-31, 1998 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-9478965

RESUMO

The G protein-coupled receptor kinases (GRKs) are critical enzymes in the desensitization of activated G protein-coupled receptors. Six members of the GRK family have been identified to date. Among these enzymes, GRK1 (rhodopsin kinase) is involved in phototransduction and is the most specialized of the family. GRK1 phosphorylates photoactivated rhodopsin, initiating steps in its deactivation. In this study, we found that human retina expressed all GRKs except GRK4. Based on results of molecular cloning and immunolocalization, it appears that both rod and cone photoreceptors express GRK1. This conclusion was supported by the cloning of only GRK1 from cone-dominated chicken retina. Human photoreceptors also transcribe a splice variant of GRK1, which differs in its C-terminal region next to the catalytic domain. This novel variant, GRK1b, is produced by retention of the last intron. mRNA encoding GRK1b is exported to the cytosol; however, the level of the protein is relatively low compared with GRK1 (now called GRK1a), and GRK1b appears to have very low catalytic activity. Thus, these studies suggest that rods and cones, express the same form of GRK1.


Assuntos
Proteínas do Olho/biossíntese , Células Fotorreceptoras/metabolismo , Proteínas Quinases/biossíntese , Processamento Alternativo , Sequência de Aminoácidos , Animais , Especificidade de Anticorpos , Sequência de Bases , Galinhas , Éxons , Proteínas do Olho/genética , Proteínas do Olho/imunologia , Imunofluorescência , Fóvea Central , Receptor Quinase 1 Acoplada a Proteína G , Expressão Gênica , Humanos , Dados de Sequência Molecular , Proteínas Quinases/genética , Proteínas Quinases/imunologia , RNA Mensageiro/isolamento & purificação , Especificidade da Espécie , Visão Ocular
18.
Proc Natl Acad Sci U S A ; 95(1): 328-33, 1998 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-9419375

RESUMO

Rhodopsin kinase (RK), a specialized G-protein-coupled receptor kinase expressed in retina, is involved in quenching of light-induced signal transduction in photoreceptors. The role of RK in recovery after photoactivation has been explored in vitro and in vivo experimentally but has not been specifically defined in humans. We investigated the effects on human vision of a mutation in the RK gene causing Oguchi disease, a recessively inherited retinopathy. In vitro experiments demonstrated that the mutation, a deletion of exon 5, abolishes the enzymatic activity of RK and is likely a null. Both a homozygote and heterozygote with this RK mutation had recovery phase abnormalities of rod-isolated photoresponses by electroretinography (ERG); photoactivation was normal. Kinetics of rod bleaching adaptation by psychophysics were dramatically slowed in the homozygote but normal final thresholds were attained. Light adaptation was normal at low backgrounds but became abnormal at higher backgrounds. A slight slowing of cone deactivation kinetics in the homozygote was detected by ERG. Cone bleaching adaptation and background adaptation were normal. In this human in vivo condition without a functional RK and probable lack of phosphorylation and arrestin binding to activated rhodopsin, reduction of photolyzed chromophore and regeneration processes with 11-cis-retinal probably constitute the sole pathway for recovery of rod sensitivity. The role of RK in rods would thus be to accelerate inactivation of activated rhodopsin molecules that in concert with regeneration leads to the normal rate of recovery of sensitivity. Cones may rely mainly on regeneration for the inactivation of photolyzed visual pigment, but RK also contributes to cone recovery.


Assuntos
Proteínas do Olho , Cegueira Noturna/genética , Proteínas Quinases/genética , Visão Ocular/genética , Animais , Células COS , Criança , Eletrorretinografia , Éxons , Receptor Quinase 1 Acoplada a Proteína G , Deleção de Genes , Genótipo , Humanos , Cinética , Masculino , Cegueira Noturna/enzimologia , Reação em Cadeia da Polimerase
19.
Exp Eye Res ; 65(2): 249-53, 1997 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-9268593

RESUMO

We explored the possibility that defects in the rhodopsin kinase gene might cause retinitis pigmentosa (RP) by evaluating 160 unrelated cases with dominant RP and 151 unrelated cases with recessive RP. One of five missense changes was discovered in each of six cases of dominant RP, but none of the missense changes cosegregated with disease among relatives. Heterozygous missense changes were found in two cases of recessive RP, and a heterozygous frameshift mutation was found in one additional case of recessive RP. Although the same DNA sequence alterations could be found heterozygously in the only affected sibling of each index case of recessive RP, no defect could be found in the other allele. Hence, none of the changes found in the cases of dominant or recessive RP was proven to be a cause of RP. The data indicate that defects in the rhodopsin kinase gene causing RP are either rare or nonexistent.


Assuntos
Proteínas do Olho , Mutação , Proteínas Quinases/genética , Retinose Pigmentar/genética , Códon , Feminino , Receptor Quinase 1 Acoplada a Proteína G , Heterozigoto , Humanos , Masculino , Linhagem , Polimorfismo Genético
20.
Genomics ; 35(3): 571-6, 1996 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-8812493

RESUMO

G-protein-dependent receptor kinases (GRKs) play a key role in the adaptation of receptors to persistent stimuli. In rod photoreceptors rhodopsin kinase (RK) mediates rapid desensitization of rod photoreceptors to light by catalyzing phosphorylation of the visual pigment rhodopsin. To study the structure and mechanism of GRKs in human photoreceptors, we have isolated and characterized cDNA and genomic clones derived from the human RK locus using a bovine rhodopsin kinase cDNA fragment as a probe. The RK locus, assigned to chromosome 13 band q34, is composed of seven exons that encode a protein 92% identical in amino acid sequence to bovine rhodopsin kinase. The marked difference between the structure of this gene and that of another recently cloned human GRK gene suggests the existence of a wide evolutionary gap between members of the GRK gene family.


Assuntos
Cromossomos Humanos Par 13 , Proteínas do Olho , Proteínas Quinases/genética , Células Fotorreceptoras Retinianas Bastonetes , Sequência de Aminoácidos , Animais , Sequência de Bases , Bovinos , Linhagem Celular , Mapeamento Cromossômico , DNA Complementar , Éxons , Receptor Quinase 1 Acoplada a Proteína G , Humanos , Células Híbridas , Íntrons , Dados de Sequência Molecular , Homologia de Sequência de Aminoácidos
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