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4.
Actas Dermosifiliogr ; 114(9): 827-828, 2023 10.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-37286079
5.
Rev. bras. plantas med ; 18(2): 480-487, 2016. tab
Artigo em Português | LILACS, Repositório RHS | ID: lil-787950

RESUMO

RESUMO O estudo objetivou conhecer o processo de trabalho dos enfermeiros da atenção primária em relação à Política Nacional de Plantas Medicinais e Fitoterápicos. O referencial foi baseado em Guareschi e Kleinman. A abordagem foi qualitativa, descritiva. Fizeram parte dos estudos enfermeiros de 21 municípios da região Sul do estado do Rio Grande do Sul. Os dados foram coletados por questionário autoadministrado, no período de junho a agosto de 2013. A análise seguiu a proposta operativa de Minayo, emergindo dois temas: processo de trabalho dos enfermeiros e a Política Nacional de Plantas Medicinais e Fitoterápicos; viabilização desta na atenção primária. Observou-se o desconhecimento da política, apesar de ter sido constatado a indicação de plantas medicinais no processo de trabalho. A política é viável quando o enfermeiro organiza grupos, coloca em prática o diálogo interdisciplinar, e contempla a questão dos aspectos culturais do usuário.


ABSTRACT This study aimed to understand nurses’ work processes in primary health care in relation to the National Politics of Medicinal Plants and Phytotherapies. The referential was based on Guareschi and Kleinman. The approach was qualitative and descriptive. Nurses from 21 towns of Southern Rio Grande do Sul participated. Data collection was a self-administrated questionnaire, in the period of June to August of 2013. The analysis followed Minayo’s operative proposal, two themes emerged: nurses’ work processes and the National Politics of Medicinal Plants and Phytotherapies and the viability of this in primary health care. The ignorance of the policy, but they indicate medicinal plants in the work process. The policy is practicable, when the nurses make groups, put the interdisciplinary dialogue in practice and contemplate the users’ cultural aspects.


Assuntos
Humanos , Atenção Primária à Saúde , Programas Nacionais de Saúde , Enfermeiros/classificação , Plantas Medicinais/classificação , Formulação de Políticas , Enfermagem
6.
Rev. bras. plantas med ; 17(4,supl.1): 722-729, 2015.
Artigo em Português | LILACS | ID: lil-770365

RESUMO

RESUMO O objetivo deste trabalho é descrever o conhecimento popular relacionado à espinheira-santa (Maytenus ilicifolia) entre erveiros e feirantes que comercializam a planta no centro de Pelotas, Rio Grande do Sul, Brasil. Foi realizada uma pesquisa de abordagem qualitativa, exploratória e descritiva, de agosto a outubro de 2013. Entrevistas semi-estruturadas, com questões sobre os saberes e práticas relacionados à espinheira-santa, foram aplicadas a cinco erveiros e três feirantes do mercado informal de plantas medicinais. Para a análise dos dados foi utilizada a proposta operativa de Minayo, sendo Capra o referencial teórico para este estudo. Foi verificado que o saber relacionado ao uso da espinheira-santa é transmitido de geração a geração, embora existam outras fontes de conhecimento. As indicações do uso popular da espinheira-santa com finalidade terapêutica estão relacionadas a distúrbios gástricos, cicatrização e depuração do sangue. As diferentes formas dos sujeitos deste estudo interagirem com o ambiente, com sua família e em outras relações interpessoais resultam em diferentes saberes relacionados à espinheira-santa.


ABSTRACT The aim of this study was to describe the popular knowledge related to the espinheira-santa (Maytenus ilicifolia) among herbalists and marketers that sell this plant in the center of Pelotas/Rio Grande do Sul State, Brazil. A qualitative, exploratory and descriptive research was performed between August and July of 2013. Semi-structured interviews, with questions regarding the knowledge and practices related to this plant, were applied to five herbalists and three marketers inserted in the informal market of medicinal plants. The operative proposal by Minayo was used in order to analyze the data, and the theoretical framework by Capra was used in the discussion. The popular knowledge related to the use of espinheira-santa is passed on from generation to generation, although nowadays there are other sources ofinformation. The popular clueswith therapeutic purposes are related to gastric disorders, healing and blood clearance. The study participants have different forms of interaction with the environment, the family and other interpersonal relationships, resulting in different popular knowledges related to this medicinal plant.


Assuntos
Humanos , Plantas Medicinais/classificação , Participação da Comunidade , Maytenus/metabolismo , Assistência Médica/classificação
7.
Phys Chem Chem Phys ; 16(42): 23044-55, 2014 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-25247609

RESUMO

Two homopolyimides and the corresponding block copolyimide, all based on the 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA), have been synthesized and fully atomistic models have been studied using molecular dynamics (MD) simulation. The respective diamines were 1,3-phenylenediamine (mPDA) and 2,3,5,6-tetramethyl-1,4-phenylenediamine (durene). These polyimides are potential candidates for gas separation applications. The synthesized polymers were processed as dense flat membranes. The effects of diamine structure were investigated at the molecular level and an attempt to compare the structural features of homo- and block copolyimides was made. Amorphous models were generated using a hybrid pivot Monte Carlo-MD sampling preparation technique. Average model densities were validated against experimental measurements on the dense films. Cohesive energies, Hildebrand solubility parameters, conformational characteristics, intermolecular interactions and available void spaces were analysed for each system. The durene diamine was found to hinder stacking and increase the available space. This is associated with the steric effect of the methyl substituents. In general, 6FDA-mPDA/durene exhibits an intermediate behaviour with respect to its base polyimides. For most of the examined properties, the differences between different size simulated systems were minor with the exception of the free volume distribution.

8.
Rev. bras. plantas med ; 16(3): 628-636, jul.-set. 2014. tab
Artigo em Português | LILACS | ID: lil-722284

RESUMO

Uma busca foi realizada na literatura, visando sumarizar as pesquisas realizadas e obter informações acerca da utilização de plantas medicinais no processo de cicatrização de feridas. Utilizaram-se os descritores: Plantas Medicinais e Cicatrização de Feridas e seus equivalentes em inglês e espanhol, com o operador booleano "AND" em três bases eletrônicas de dados (PubMed, LILACS e COCHRANE). Foram selecionados 57 artigos para compor a revisão. Os resultados apontam que um total de 52 plantas medicinais e um composto de ervas foram estudados experimentalmente ou clinicamente, quanto aos seus efeitos no auxílio do processo de cicatrização, sendo que a maioria (88,5%) apresentou eficácia. Com isso, verifica-se que a utilização de plantas medicinais trata de importante alternativa no tratamento de feridas, que começa a fazer parte da atenção à saúde brasileira, o que sugere novos estudos de comprovação clínica, custos, e benefícios e a constante atualização acerca das publicações realizadas.


It was done a literature search aiming to sumarize earlier conducted researches and in order to obtain information on the use of medicinal plants in wound healing process. The descriptors used were as follows: Medicinal Plants and Wound Healing and their equivalents in English and Spanish with the Boolean operator "AND" in three electronic databases (PubMed, LILACS and COCHRANE). Fifty seven articles were chosen to compose the review. The findings from a total of fifty two medicinal plants and one herbal compound that were experimentally or clinically studied in respect to their effects in wound healing process indicate that the majority of them (eighty eight point five per cent) showed efficacy. Thus, it can be seen that the use of medicinal plants is an important alternative in wounds treatment that becomes part of Brazilian health care, suggesting further studies of clinical evidence, costs and benefits and constantly updating on produced publications.


Assuntos
Plantas Medicinais/efeitos adversos , Cicatrização/fisiologia , Extratos Vegetais/efeitos adversos , Saúde Pública/classificação , Fitoterapia/instrumentação
9.
Rev. bras. plantas med ; 14(1): 50-56, 2012. tab
Artigo em Português | LILACS | ID: lil-644613

RESUMO

Este trabalho teve como objetivo investigar as plantas medicinais utilizadas por idosos assistidos em uma Unidade Básica de Saúde de Pelotas-RS, com diagnóstico de Diabetes mellitus, como terapia complementar no tratamento dos sintomas da doença. Caracterizou-se por pesquisa qualitativa, realizada em julho de 2009, no município de Pelotas-RS. Foram entrevistados 18 idosos com idade entre 60 e 77 anos, sendo 14 do sexo feminino. Os participantes citaram 20 plantas medicinais utilizadas como terapia complementar no tratamento do Diabetes mellitus. Entre estas, as mais citadas utilizadas para diminuir os níveis de glicose no sangue foram Sphagneticola trilobata, Bauhinia spp. e Syzygium cumini, sendo que para as duas últimas há comprovação científica do efeito hipoglicemiante. A infusão foi a forma de preparo predominante. Considera-se importante a realização de estudos farmacológicos que investiguem os efeitos das plantas utilizadas pela população, a fim de que o uso proporcione os benefícios desejados e não cause danos à saúde.


This study aimed to investigate medicinal plants used as complementary therapy by the elderly with diabetes mellitus, assisted by a Health Basic Unit in Pelotas (RS, Brazil). This qualitative research was conducted in July 2009. Eighteen 60 to 77 years old elderly (14 of them female) were interviewed. The participants identified 20 medicinal plants used as complementary therapies in the treatment of diabetes mellitus. Among these, the most used ones to reduce the levels of glucose in the blood were Sphagneticola trilobata, Bauhinia spp. and Syzygium cumini. For the last two plants, there are scientific proofs of hypoglycemic effects. The infusion was the predominant form of preparation. Studies to investigate the pharmacological effects of plants used by the population have become very important, for providing scientific information on their possible health benefits and side effects.


Assuntos
Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Idoso , Plantas Medicinais/efeitos adversos , Diabetes Mellitus/diagnóstico , Diabetes Mellitus/reabilitação , Terapias Complementares/instrumentação , Doença Crônica , Enfermagem
10.
J Am Chem Soc ; 130(29): 9332-41, 2008 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-18576638

RESUMO

Apurinic/apyrimidinic endonuclease 1 (APE1), a member of the divalent cation-dependent phosphoesterase superfamily of proteins that retain the conserved four-layered alpha/beta-sandwich structural core, is an essential protein that functions as part of base excision repair to remove mutagenic and cytotoxic abasic sites from DNA. Using low-temperature solid-state (25)Mg NMR spectroscopy and various mutants of APE1, we demonstrate that Mg(2+) binds to APE1 and a functional APE1-substrate DNA complex with an overall stoichiometry of one Mg(2+) per mole of APE1 as predicted by the X-ray work of Tainer and co-workers (Mol, C. D.; Kuo, C. F.; Thayer, M. M.; Cunningham, R. P.; Tainer, J. A. Nature 1995, 374 , 381-386). However, the NMR spectra show that the single Mg(2+) site is disordered. We discuss the probable reasons for the disorder at the Mg(2+) binding site. The most likely source of this disorder is arrangement of the protein-ligands about the Mg(2+) (cis and trans isomers). The existence of these isomers reinforces the notion of the plasticity of the metal binding site within APE1.


Assuntos
Dano ao DNA , Reparo do DNA , DNA Liase (Sítios Apurínicos ou Apirimidínicos)/química , DNA Liase (Sítios Apurínicos ou Apirimidínicos)/metabolismo , Magnésio/química , Magnésio/metabolismo , Ressonância Magnética Nuclear Biomolecular/métodos , Sequência de Bases , Humanos , Cinética , Mutagênese Sítio-Dirigida , Ligação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Especificidade por Substrato
11.
Poult Sci ; 85(4): 706-11, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16615354

RESUMO

Axial x-ray microcomputed tomography is a cost-effective technique with the potential to assess bone mineral density (mg/cc) in both cortical and cancellous bone in Single Comb White Leghorn hens. The technique requires little sample preparation and involves relatively simple data processing. The system described in this research is based on compact fan-beam type tomography, using a tungsten-anode x-ray tube with a relatively small focal spot (approximately 5 microm), coupled with a high-resolution x-ray detector system (approximately 10 microm). To produce a real 3-D data set using microcomputed tomography, x-ray projection views were acquired at 720 equally spaced angular positions (0.5 degrees) around the object of interest. These groups of views were then used to reconstruct a computed tomography image. A test grid with orthogonal test lines was used to calculate bone volume and bone surface. From these calculations, parallel plate equations were used to derive trabecular architectural parameters such as average trabecular plate thickness and average trabecular plate separation. Three-dimensional microarchitecture was evaluated using specialized stereological analysis software. Significant relationships between apparent bone mineral density (mg/cc) and 3-D structure were observed in femoral specimens from 66-wk-old Single Comb White Leghorn hens.


Assuntos
Densidade Óssea/fisiologia , Osso e Ossos/anatomia & histologia , Galinhas/anatomia & histologia , Tomografia Computadorizada por Raios X/veterinária , Animais , Feminino , Membro Posterior/anatomia & histologia , Membro Posterior/metabolismo , Tomografia Computadorizada por Raios X/métodos
12.
Cytogenet Genome Res ; 105(2-4): 412-21, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15237229

RESUMO

RNA interference (RNAi) has been extensively used for sequence-specific silencing of gene function in mammalian cells. The latest major breakthrough in the application of RNAi technology came from experiments demonstrating RNAi-mediated gene repression in mice and rats. After more than two decades of functional mouse research aimed at developing and continuously improving transgenic and knock-out technology, the advent of RNAi knock-down mice represents a valuable new alternative for studying gene function in vivo. In this review we provide some basic insight as to how RNAi can induce gene silencing to then focus on recent findings concerning the applicability of RNAi for regulating gene function in the mouse. Reviewed topics will include delivery methods for RNAi-mediating molecules, a comparison between traditional knock-out and innovative transgenic RNAi technology and the generation of graded RNAi knock-down phenotypes. Apart from the exciting possibilities RNAi provides for studying gene function in mice, we discuss several caveats and limitations to be considered. Finally, we present prospective strategies as to how RNAi technology might be applied for generating conditional and tissue-restricted knock-down mice.


Assuntos
Técnicas Genéticas , Interferência de RNA , Alelos , Animais , Previsões , Marcação de Genes , Variação Genética , Genômica , Camundongos
13.
J Environ Qual ; 32(4): 1414-21, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12931897

RESUMO

Irrigated areas in Brazil's Central São Francisco River Valley have experienced declines in productivity, which may be a reflection of changes in soil chemical properties due to management. This study was conducted to compare the chemical composition of soil solutions and cation exchange complexes in a five-year-old grove of irrigated mango (Mangifera indica L. cv. Tommy Atkins) with that of an adjacent clearing in the native caatinga vegetation. A detailed physiographic characterization of the area revealed a subsurface rock layer, which was more undulating than the current land surface, and identified the presence of a very saline and sodic (1045 microS cm(-1), sodium adsorption ratio [SAR] = 5.19) ground water table. While changes in concentrations of Ca, Mg, and K could be attributed to direct management inputs (fertilization and liming with dolomite), increases in Na suggested average annual capillary rise from the ground water table of 28 L m(-2). Accordingly, soil salinity levels appeared to be more dependent on surface elevation than the elevation of the rock layer or sediment thickness. The apparent influence of land surface curvature on water redistribution and the solution chemistry was more pronounced under irrigated mango production. In general, salinity levels had doubled in the mango grove and nearly tripled under the canopies, after only five years of irrigation. Though critical saline or sodic conditions were not encountered, the changes observed indicate a need for more adequate monitoring and management of water and salt inputs despite the excellent water quality of the São Francisco River.


Assuntos
Cloreto de Sódio/análise , Solo , Abastecimento de Água , Agricultura , Brasil , Monitoramento Ambiental , Sedimentos Geológicos/química , Mangifera , Água/química
14.
J Pediatr Health Care ; 15(5): 236-43, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11562641

RESUMO

INTRODUCTION: With the advent of new vaccines, improvements in established vaccines, and the availability of new combination vaccines, parents' decisions about vaccinating their children have become more complicated. This study examined parents' decision-making processes pertaining to whether to have their children vaccinated for varicella to gain a better understanding about how parents make vaccination decisions for their children. The "Awareness-to-Action Model" was used to examine parents' decision-making process before the action to vaccinate or refuse vaccination occurs. METHOD: This study used a cross-sectional design and logistic regression to test the explanatory power of several factors related to the parental decision-making process. A stratified random sample of 262 members of Kaiser Permanente Hawaii participated in the study. Data were collected through telephone interviews. RESULTS: In the "Awareness-to-Action Model," the decision construct was statistically significant in explaining parents' decisions to have their child vaccinated. The overall model correctly classified 80% of the sample as accepters or nonaccepters of the vaccination for their child. This study provides a model that enables health care providers to understand parental decisions about vaccines. This knowledge can help target interventions to increase vaccine compliance, thus minimizing the risk of diseases preventable by vaccine.


Assuntos
Varicela/prevenção & controle , Tomada de Decisões , Conhecimentos, Atitudes e Prática em Saúde , Imunização , Adulto , Pré-Escolar , Estudos Transversais , Feminino , Havaí , Humanos , Lactente , Modelos Logísticos , Masculino , Modelos Psicológicos
15.
Gerontologist ; 41(1): 51-60, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11220815

RESUMO

The authors interviewed adults in five ethnic groups, used factor analysis to quantify attitudes toward planning for death, and used path analysis to test the relative influence of respondent characteristics, including ethnicity, and attitude factors (Advocacy to Discuss/Document Wishes, Trust in Family and Physician to Make Decisions, Reliance on Religious Guidance, Fears and Anxiety About Life's End, and Fatalism About Death's Timing) on support for physician-assisted suicide (PAS). Findings verified that attitude factors had a direct effect on PAS support but that, contrary to the hypothesis, ethnicity had a direct effect on support for PAS as well.


Assuntos
Atitude Frente a Morte , Suicídio Assistido , Adulto , Idoso , Asiático , Catolicismo , Características Culturais , Interpretação Estatística de Dados , Educação , Etnicidade , Humanos , Entrevistas como Assunto , Pessoa de Meia-Idade , Religião , Inquéritos e Questionários , Estados Unidos
16.
Mol Carcinog ; 28(1): 31-41, 2000 May.
Artigo em Inglês | MEDLINE | ID: mdl-10820486

RESUMO

In order to determine the role of N-ras overexpression and mutation in malignant liver cell transformation, wild-type and mutated N-ras were transfected into the rat liver epithelial cell line OC/CDE 22, and N-ras expression, growth kinetics, growth in soft agar, and tumorigenicity in vivo as well as the involvement of the mitogen-activated protein kinase (MAPK) signal transduction pathway in the expression of the malignant phenotype were analyzed. Although OC/CDE 22 cells transfected with wild-type N-ras showed a high expression of N-ras at the mRNA and protein levels, the cells did not grow in soft agar and were not tumorigenic in vivo. In contrast, OC/CDE 22 cells transfected with mutated N-ras showed anchorage-independent growth and were tumorigenic. When cultured in fetal bovine serum-supplemented medium, OC/CDE 22 cells expressing mutant N-ras showed a higher proliferation rate than nontransfected OC/CDE 22 cells or OC/CDE 22 cells transfected with wild-type N-ras. When held in serum-free medium, untreated OC/CDE 22 cells did not grow at all, while OC/CDE 22 cells transfected with wild-type or mutant N-ras proliferated at a similar rate, which can be explained by the high MAPK activity in these cells. Selective inhibition of the MAPK cascade abolished the growth of OC/CDE 22 cells carrying mutant N-ras in soft agar; furthermore, these cells ceased pile up and formed monolayers on Petri dishes. Thus, activation of the MAPK signaling pathway, though alone not sufficient to malignantly transform liver cells (as shown in liver cells overexpressing wild-type N-ras), is not only essential for growth control but also for the expression of the malignant phenotype (as demonstrated in liver cells transformed by mutated N-ras).


Assuntos
Transformação Celular Neoplásica , Genes ras , Neoplasias Hepáticas/genética , Animais , Bovinos , Linhagem Celular , Regulação Neoplásica da Expressão Gênica , Mutação , Ratos
17.
J Burn Care Rehabil ; 21(2): 162-4; discussion 164-70, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10752750

RESUMO

Cigarettes are the most common ignition source for fatal house fires, which cause approximately 29% of the fire deaths in the United States. A common scenario is the delayed ignition of a sofa, chair, or mattress by a lit cigarette that is forgotten or dropped by a smoker whose alertness is impaired by alcohol or medication. Cigarettes are designed to continue burning when left unattended. If they are dropped on mattresses, upholstered furniture, or other combustible material while still burning, their propensity to start fires varies depending on the cigarette design and content. The term "fire-safe" has evolved to describe cigarettes designed to have a reduced propensity for igniting mattresses and upholstered furniture. Legislative interest in the development of fire-safe smoking materials has existed for more than 50 years. Studies that showed the technical and economic feasibility of commercial production of fire-safe cigarettes were completed more than 10 years ago. Despite this, commercial production of fire-safe smoking materials has not been undertaken. The current impasse relates to the lack of consensus on a uniform test method on which to base a standard for fire-safe cigarettes. Although the fire-safe cigarette is a potentially important burn prevention tool, commercial production of such cigarettes will not occur until a standard against which fire-starting performance can be measured has been mandated by law at the state or federal level. The burn care community can play a leadership role in such legislative efforts.


Assuntos
Queimaduras/prevenção & controle , Incêndios/prevenção & controle , Nicotiana , Plantas Tóxicas , Fumar/legislação & jurisprudência , Humanos , Prevenção Primária/métodos , Segurança , Estados Unidos
18.
Development ; 126(24): 5669-78, 1999 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-10572043

RESUMO

Recent studies of inner ear development suggest that hair cells and support cells arise within a common equivalence group by cell-cell interactions mediated by Delta and Notch proteins. We have extended these studies by analyzing the effects of a mutant allele of the zebrafish deltaA gene, deltaA(dx2), which encodes a dominant-negative protein. deltaA(dx2/dx2 )homozygous mutants develop with a 5- to 6-fold excess of hair cells and a severe deficiency of support cells. In addition, deltaA(dx2/dx2) mutants show an increased number of cells expressing pax2.1 in regions where hair cells are normally produced. Immunohistological analysis of wild-type and deltaA(dx2/dx2) mutant embryos confirmed that pax2.1 is expressed during the initial stages of hair cell differentiation and is later maintained at high levels in mature hair cells. In contrast, pax2.1 is not expressed in support cells. To address the function of pax2.1, we analyzed hair cell differentiation in no isthmus mutant embryos, which are deficient for pax2.1 function. no isthmus mutant embryos develop with approximately twice the normal number of hair cells. This neurogenic defect correlates with reduced levels of expression of deltaA and deltaD in the hair cells in no isthmus mutants. Analysis of deltaA(dx2/dx2); no isthmus double mutants showed that no isthmus suppresses the deltaA(dx2) phenotype, probably by reducing levels of the dominant-negative mutant protein. This interpretation was supported by analysis of T(msxB)(b220), a deletion that removes the deltaA locus. Reducing the dose of deltaA(dx2) by generating deltaA(dx2)/T(msxB)(b220 )trans-heterozygotes weakens the neurogenic effects of deltaA(dx2), whereas T(msxB)(b220) enhances the neurogenic defects of no isthmus. mind bomb, another strong neurogenic mutation that may disrupt reception of Delta signals, causes a 10-fold increase in hair cell production and is epistatic to both no isthmus and deltaA(dx2). These data indicate that deltaA expressed by hair cells normally prevents adjacent cells from adopting the same cell fate, and that pax2.1 is required for normal levels of Delta-mediated lateral inhibition.


Assuntos
Proteínas de Ligação a DNA/genética , Regulação da Expressão Gênica no Desenvolvimento , Células Ciliadas Auditivas/embriologia , Proteínas de Membrana/genética , Fatores de Transcrição/genética , Animais , Biomarcadores , Diferenciação Celular , Orelha Interna/citologia , Orelha Interna/embriologia , Dosagem de Genes , Células Ciliadas Auditivas/citologia , Peptídeos e Proteínas de Sinalização Intracelular , Mutagênese , Fator de Transcrição PAX2 , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Proteínas de Peixe-Zebra
19.
Exp Cell Res ; 236(2): 418-26, 1997 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-9367626

RESUMO

In the present study the establishment and characterization of a nontumorigenic liver epithelial cell line (HACL-1) derived from a human hepatocellular adenoma is described. The HACL-1 cells have a finite life span (i.e., they proliferate for a period of 2 months and then senesce), show cell-cell contact inhibition, do not grow in soft agar, are not tumorigenic when injected in nude mice, and possess a normal diploid karyotype. The cultured cells resemble hepatocytes, but exhibit some features of dedifferentiation. At the ultrastructural level the cells are endowed with round or oval nuclei, abundant cytoplasmic organelles, and varying amounts of glycogen. The rough endoplasmic reticulum is disorganized, while peroxisomes and matrix granules within mitochondria are lacking. HACL-1 cells are cytokeratin 18-positive as well as (transiently) albumin- and alpha-fetoprotein-positive, but do not express cytokeratin 19. Furthermore, no mutations were observed in exons 5-8 of the tumor suppressor gene p53. Taken together these results show that HACL-1 cells are nontumorigenic proliferating liver epithelial cells, which might prove to be of great value in future studies on diverse aspects of human liver cell biology and carcinogenesis.


Assuntos
Adenoma de Células Hepáticas , Biomarcadores Tumorais , Neoplasias Hepáticas , Células Tumorais Cultivadas , Adenoma de Células Hepáticas/patologia , Animais , Senescência Celular , Células Epiteliais/patologia , Genes p53 , Humanos , Cariotipagem , Neoplasias Hepáticas/patologia , Camundongos , Camundongos Nus , Especificidade de Órgãos , Análise de Sequência de DNA , Células Tumorais Cultivadas/patologia
20.
Biochemistry ; 35(36): 11605-11, 1996 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-8794740

RESUMO

Carbonic anhydrase V (CA V) is a mitochondrial enzyme that catalyzes the hydration of CO2 to produce bicarbonate and a proton. The catalytic properties of wild-type murine CA V suggest the presence of a proton shuttle residue having pKa = 9.2, the role of which is to transfer a proton from zinc-bound water to solution in the hydration direction to regenerate the zinc hydroxide form of the enzyme. Two likely candidates for shuttle residues are the tyrosines at positions 64 and 131 in the active site cavity. The crystal structure of wild-type carbonic anhydrase V [Boriack-Sjodin et al. (1995) Proc. Natl. Acad. Sci. U.S.A. 92, 10949-10953] shows that the side chain of Tyr 64 is forced into an orientation pointing away from the zinc by Phe 65, although Tyr 131 is oriented toward the zinc. We have prepared mutants of murine CA V replacing both Tyr 64 and Tyr 131 with His and Ala and investigated the proton shuttle mechanism using stopped-flow spectrophotometry and the depletion of 18O from CO2 measured by mass spectrometry. Experiments with both single and double mutations showed that neither position 64 nor position 131 was a prominent site for proton transfer. However, a double mutant of CA V containing the two replacements, Tyr 64-->His and Phe 65-->Ala, demonstrated enhanced proton transfer with an apparent pKa of 6.8 and maximal contribution to kcat of 2.2 x 10(5) s-1. In addition to the altered catalytic properties, the crystal structure of the His 64/Ala 65 double mutant strongly suggested proton transfer by His 64 after removal of the steric hindrance of Phe 65. This is the first structure-based design of an efficient proton transfer site in an enzyme.


Assuntos
Anidrases Carbônicas/química , Prótons , Animais , Sítios de Ligação , Dióxido de Carbono/metabolismo , Anidrases Carbônicas/genética , Anidrases Carbônicas/metabolismo , Catálise , Cristalografia por Raios X , Escherichia coli/genética , Cinética , Camundongos , Camundongos Endogâmicos BALB C , Mitocôndrias/enzimologia , Modelos Moleculares , Mutagênese Sítio-Dirigida , Conformação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Tirosina/química , Tirosina/metabolismo , Água/metabolismo , Zinco/metabolismo
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