RESUMO
BACKGROUND: The skin is the first organ that manifests changes in response to zinc deficiency. However, the molecular mechanism underlying how zinc is involved in skin homeostasis, especially its epigenetic regulation, is largely unknown. OBJECTIVES: In this study we demonstrate the importance of zinc levels and the zinc transporter ZIP10 in the epigenetic maintenance of human epidermal homeostasis. METHODS: Adult human skin, including skin appendages, were stained with anti-ZIP10 antibody. Histone acetyltransferase (HAT) activity was assessed after treating human keratinocytes with ZIP10 small interfering (si)RNAs or the zinc chelator TPEN. ZIP10- or HAT-regulated genes were analysed based on limma bioinformatics analysis for keratinocytes treated with ZIP10 siRNAs or a HAT inhibitor, or using a public database for transcription factors. A reconstituted human skin model was used to validate the role of ZIP10 in epidermal differentiation and the functional association between ZIP10 and HAT. RESULTS: ZIP10 is predominantly expressed in the interfollicular epidermis, epidermal appendages and hair follicles. ZIP10 depletion resulted in epidermal malformations in a reconstituted human skin model via downregulation of the activity of the epigenetic enzyme HAT. This decreased HAT activity, resulting from either ZIP10 depletion or treatment with the zinc chelator TPEN, was readily restored by zinc supplementation. Through bioinformatics analysis for gene sets regulated by knockdown of SLC39A10 (encoding ZIP10) and HAT inhibition, we demonstrated that ZIP10 and HATs were closely linked with the regulation of genes related to epidermal homeostasis, particularly filaggrin and metallothionein. CONCLUSIONS: Our study suggests that ZIP10-mediated zinc distribution is crucial for epidermal homeostasis via HATs. Therefore, zinc-dependent epigenetic regulation could provide alternatives to maintaining healthy skin or alleviating disorders with skin barrier defects.
Assuntos
Proteínas de Transporte de Cátions/metabolismo , Epiderme/enzimologia , Epigênese Genética/fisiologia , Histona Acetiltransferases/metabolismo , Zinco/deficiência , Adulto , Benzoatos/farmacologia , Proteínas de Transporte de Cátions/genética , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/genética , Linhagem Celular , Quelantes/farmacologia , Regulação para Baixo , Epiderme/efeitos dos fármacos , Epigênese Genética/efeitos dos fármacos , Etilenodiaminas/farmacologia , Proteínas Filagrinas , Técnicas de Silenciamento de Genes , Histona Acetiltransferases/antagonistas & inibidores , Histona Acetiltransferases/genética , Humanos , Ácidos Hidroxâmicos , Queratinócitos , Nitrobenzenos , Cultura Primária de Células , Pirazóis/farmacologia , Pirazolonas , RNA Interferente Pequeno/metabolismo , Zinco/administração & dosagem , Zinco/metabolismoRESUMO
BACKGROUND: Cell migration plays a major role in the immune response and in tumorigenesis. Interferon-inducible T-cell alpha chemoattractant (ITAC) elicits a strong chemotactic response from immune cells. OBJECTIVES: To examine the effect of ITAC on melanocyte migration and pigmentation and its involvement in related disorders, and to investigate potential key players in these processes. METHODS: Human melanocytes or melanoma cells were treated with ITAC and a migration assay was carried out. Global gene expression analysis was performed to find genes regulated by ITAC treatment. The function of key players involved in ITAC-induced cellular processes was addressed using knockdown or overexpression experiments in combination with ITAC treatment. ITAC expression in the inflammation-associated hypopigmentary disorder, vitiligo, was examined. RESULTS: Among CXCR3 ligands, only ITAC induced melanocyte migration. ITAC treatment upregulated the expression of histone deacetylase 5 (HDAC5) and downregulated that of p53, a known target of HDAC5. Through knockdown or overexpression of HDAC5 and p53, we confirmed that HDAC5 mediates ITAC-induced migration by decreasing levels of p53 via deacetylation. In addition, ITAC treatment could decrease pigmentation in a p53- and HDAC5-dependent manner. Finally, the increased migration of human melanoma cells by ITAC treatment and the increased ITAC expression in the epidermis of vitiligo skin were verified. CONCLUSIONS: This study provides in vitro evidence for the migratory and hypopigmentation effects of ITAC on melanocytic cells, gives translational insights into the roles of ITAC in pathological conditions, and suggests that HDAC5 and its substrate p53 are potent targets for regulating ITAC-induced cellular processes.
Assuntos
Movimento Celular/efeitos dos fármacos , Quimiocina CXCL11/farmacologia , Histona Desacetilases/metabolismo , Hipopigmentação/enzimologia , Melanócitos/efeitos dos fármacos , Células Cultivadas , Regulação para Baixo/fisiologia , Células Epidérmicas , Técnicas de Silenciamento de Genes , Histona Desacetilases/deficiência , Humanos , RNA Mensageiro/metabolismo , Receptores CXCR/metabolismo , Proteínas Repressoras/deficiência , Proteína Supressora de Tumor p53/metabolismo , Regulação para Cima/fisiologiaRESUMO
BACKGROUND: Maintenance of water balance in the stratum corneum (SC) is determined by the content of intercellular lipids and natural moisturizing factors (NMFs) in corneocytes. AIM: To investigate the association between the NMFs and (pro)filaggrin and the proteases responsible for the processing of (pro)filaggrin to NMFs in the SC of hydrated and dry skin areas of healthy human subjects. METHODS: The SC hydration state and the transepidermal water loss (TEWL) were measured using a Corneometer and a Tewameter, respectively. Proteases, (pro)filaggrin and NMFs were extracted from SC samples obtained by tape-stripping of the tested skin. Expression levels of (pro)filaggrin were determined by dot blotting and western blotting, and total NMFs by ultra-high performance liquid chromatography. Expression of the proteases caspase-14, calpain-1 and bleomycin hydrolase was measured by western blotting. RESULTS: The levels of (pro)filaggrin were not significantly different between hydrated and dry skin, whereas the level of total NMFs was significantly reduced in dry skin. A negative correlation between (pro)filaggrin and NMFs was found in dry skin (Pearson correlation coefficient r = - 0.57, *P < 0.05). Bleomycin hydrolase expression was significantly decreased in the SC of dry skin. CONCLUSIONS: These results suggest that the low hydration state of dry skin may be due to the reduction in (pro)filaggrin degradation caused by decreased bleomycin hydrolase expression.
Assuntos
Cisteína Endopeptidases/metabolismo , Epiderme/metabolismo , Proteínas de Filamentos Intermediários/metabolismo , Adulto , Calpaína/metabolismo , Caspase 14/metabolismo , Cromatografia Líquida de Alta Pressão , Epiderme/fisiologia , Feminino , Proteínas Filagrinas , Humanos , Masculino , Pessoa de Meia-Idade , Perda Insensível de Água/fisiologiaRESUMO
BACKGROUND: Cathepsin G, a serine protease that is activated by ultraviolet (UV) radiation, increases matrix metalloproteinase-1 (MMP-1) expression in fibroblasts through fibronectin (Fn) fragmentation and promotes the conversion of proMMP-1 to active MMP-1. OBJECTIVES: This study investigated whether [2-[3-[[(1-benzoyl-4-piperidinyl)methylamino]carbonyl]-2-naphthalenyl]-1-(1-naphthalenyl)-2-oxoethyl]-phosphonic acid (KPA), a cathepsin G inhibitor, plays any role in extracellular matrix (ECM) damage in an in vitro 3D dermal equivalent (DE) and an in vivo ultraviolet B (UVB)-irradiated hairless mice. METHODS: We examined the potential ECM-protective effects of a cathepsin G inhibitor in an in vitro 3D DE model and an in vivo UVB-irradiated hairless mouse skin model. RESULTS: Among five known serine protease inhibitors, KPA showed the strongest potency and selectivity against cathepsin G. KPA inhibited the cathepsin G-mediated MMP-1 increase and alleviated the downregulation of mRNAs encoding collagen and tissue inhibitor of matrix metalloproteinase-1 in an in vitro 3D DE model. Most importantly, topical application of KPA (0.025%) to the dorsal skin of hairless mice enhanced collagen expression and attenuated UVB-induced Fn fragmentation and upregulation of MMP-2 and MMP-9 activities. CONCLUSIONS: Cathepsin G inhibitors may be useful for the prevention of UVB-induced photoaging through amelioration of ECM damage and MMP upregulation.
Assuntos
Catepsina G/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Fibronectinas/metabolismo , Naftalenos/farmacologia , Compostos Organofosforados/farmacologia , Piperidinas/farmacologia , Envelhecimento da Pele/efeitos dos fármacos , Pele/efeitos da radiação , Raios Ultravioleta/efeitos adversos , Animais , Western Blotting , Colágeno/metabolismo , Elastina/química , Elastina/metabolismo , Ensaio de Imunoadsorção Enzimática , Feminino , Metaloproteinase 1 da Matriz/metabolismo , Camundongos , Camundongos Pelados , Modelos Animais , Reação em Cadeia da Polimerase em Tempo Real , Pele/metabolismo , Inibidor Tecidual de Metaloproteinase-1/metabolismoRESUMO
Several studies have reported that 1,2-alkanediols show increasing anti-microbial activity as their alkane chain length increases. However, there are no reports on the influence of alkane chain length on the skin irritation potential of 1,2-alkanediols. To investigate the influence of alkane chain length on the skin irritation potential of 1,2-alkanediols. The objective and subjective (sensory) skin irritation potentials of five 1,2-alkanediols - 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol and 1,2-decanediol - were evaluated. We also estimated percutaneous absorption by measuring in vitro skin penetration using a Franz diffusion cell system. Like anti-microbial activity, sensory irritation potential increased as alkane chain length increased, most likely due to increasing membrane interference and/or intrinsic toxicity of 1,2-alkanediols. 1,2-Hexanediol showed the lowest objective skin irritation potential, which increased when the alkane chain length decreased or increased. Furthermore, percutaneous absorption negatively correlated with the alkane chain length of 1,2-alkanediols. These results show that a lower skin absorption potential is not indicative of a low skin irritation potential. Our results suggest that the factors and processes involved in skin irritation potential are complex and that skin irritation potential is influenced by intrinsic toxicity and the potential for penetration or integration in the lipid bilayer.
Assuntos
Alcanos/química , Alcanos/toxicidade , Irritantes/química , Irritantes/toxicidade , Pele/efeitos dos fármacos , Adulto , Anti-Infecciosos/química , Anti-Infecciosos/toxicidade , Feminino , Humanos , Masculino , Testes de Sensibilidade MicrobianaRESUMO
BACKGROUND: In this retrospective study, we developed and internally validate a nomogram for predicting 5-year metastasis probability for nonmetastatic extremity osteosarcoma. PATIENTS AND METHODS: We reviewed 365 osteosarcoma patients treated at our institute from 1990 to 2003. Clinicopathologic variables were recorded. Multivariate analysis using Cox proportional hazards regression was done and this Cox model was used as the basis for the nomogram. RESULTS: By American Joint Committee on Cancer (AJCC) staging system, 141 patients (38.6%) were stage IIA and 224 (61.4%) were stage IIB. Multivariate Cox model identified patient age at diagnosis, tumor size, humeral location, and tumor necrosis rate after chemotherapy as correlated with metastasis-free survival. The degree of contribution of each covariate to the total point was tumor location, tumor necrosis rate, maximal tumor diameter, and age in decreasing order. The concordance index for the model was 0.78. Nomogram discrimination was superior to that of AJCC stage (concordance index 0.78 versus 0.68; P = 0.02) and histologic response grouping (concordance index 0.78 versus 0.69; P = 0.0004). CONCLUSIONS: We devised a nomogram for nonmetastatic osteosarcoma that proposes improved estimates of metastasis over AJCC staging system or tumor necrosis rate. We suggest that this nomogram allows individualized risk assessments and could be used as the basis for risk-adapted therapy.
Assuntos
Antineoplásicos/uso terapêutico , Neoplasias Ósseas/tratamento farmacológico , Neoplasias Ósseas/cirurgia , Nomogramas , Procedimentos Ortopédicos , Osteossarcoma/tratamento farmacológico , Osteossarcoma/cirurgia , Adolescente , Adulto , Fatores Etários , Neoplasias Ósseas/mortalidade , Neoplasias Ósseas/patologia , Quimioterapia Adjuvante , Criança , Pré-Escolar , Extremidades , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Necrose , Terapia Neoadjuvante , Metástase Neoplásica , Estadiamento de Neoplasias , Osteossarcoma/mortalidade , Osteossarcoma/patologia , Seleção de Pacientes , Valor Preditivo dos Testes , Modelos de Riscos Proporcionais , Reprodutibilidade dos Testes , Estudos Retrospectivos , Medição de Risco , Fatores de Tempo , Resultado do Tratamento , Adulto JovemRESUMO
Two separate libraries, prepared via parallel synthesis, were employed to identify low-molecular-weight SH2-targeted ligands for the Lck tyrosine protein kinase. These libraries were constructed to furnish non-amino acid analogues of the (1) Glu-Glu and (2) Ile residues of the Lck SH2 domain peptide ligand Ac-pTyr-Glu-Glu-Ile-amide. The lead compound acquired in this study exhibits a dissociation constant for the Lck SH2 domain that is comparable to that displayed by Ac-pTyr-Glu-Glu-Ile-amide. These results demonstrate that the standard amino acid residues Glu-Glu-Ile can be completely replaced with non-amino acid moieties without loss of SH2 affinity.
Assuntos
Amidas/síntese química , Cumarínicos/síntese química , Proteína Tirosina Quinase p56(lck) Linfócito-Específica/química , Tirosina/análogos & derivados , Tirosina/síntese química , Domínios de Homologia de src , Amidas/química , Técnicas de Química Combinatória , Cumarínicos/química , Ensaio de Imunoadsorção Enzimática , Ligantes , Tirosina/químicaRESUMO
The adjacent yrhI and yrhJ genes were identified by the Bacillus subtilis genome sequencing project. We now report that yrhJ (renamed CYP102A3) encodes a cytochrome P450 and that yrhI (renamed bscR) encodes a repressor that negatively regulates the transcription of the bscR-CYP102A3 operon. The transcriptional initiation site of bscR has been mapped by primer extension analysis. An 18-bp perfect palindromic sequence centered 65.5 bp downstream from the transcriptional initiation site of bscR has been identified as the binding site for BscR by gel mobility shift assays. Base substitutions in the 18-bp inverted repeat resulted in derepression of the bscR-xylE transcriptional fusion in vivo. bscR-xylE fusion studies and Northern blot analysis revealed that oleic acid and palmitate could induce the expression of the bscR-CYP102A3 operon to a considerable extent. However, only oleic acid was capable of preventing the binding of BscR to its operator DNA in vitro, suggesting that the induction of CYP102A3 expression by oleic acid and palmitate in B. subtilis might be mediated through different mechanisms.
Assuntos
Bacillus subtilis/genética , Proteínas de Bactérias/fisiologia , Sistema Enzimático do Citocromo P-450/genética , Regulação Bacteriana da Expressão Gênica , Regulação Enzimológica da Expressão Gênica , Oxigenases de Função Mista/genética , Óperon , Proteínas Repressoras/fisiologia , Sequência de Aminoácidos , Bacillus subtilis/efeitos dos fármacos , Bacillus subtilis/metabolismo , Proteínas de Bactérias/genética , Sequência de Bases , Sítios de Ligação , Sistema Enzimático do Citocromo P-450/biossíntese , Sistema Enzimático do Citocromo P-450/química , Indução Enzimática , Repressão Enzimática , Oxigenases de Função Mista/biossíntese , Oxigenases de Função Mista/química , NADPH-Ferri-Hemoproteína Redutase , Ácido Oleico/farmacologia , Palmitatos/farmacologia , Regiões Promotoras Genéticas , Estrutura Terciária de Proteína , RNA Bacteriano/biossíntese , Sequências Repetitivas de Ácido Nucleico , Proteínas Repressoras/genética , Sítio de Iniciação de Transcrição , Ativação TranscricionalRESUMO
The NBT test is a non-specific test of neutrophil membrane stimulation which has application to the study of neutrophil function, particularly in the septicaemic patient. An improved cytochemical test which eliminates potential sources of laboratory error has been developed. Venous or capillary blood samples may be studied and the technique can be applied to the neutropenic patient since available neutrophils are concentrated by cytocentrifugation. Clinical evaluation in 443 patients is described.
Assuntos
Infecções/diagnóstico , Nitroazul de Tetrazólio , Sais de Tetrazólio , Adolescente , Adulto , Idoso , Infecções Bacterianas/diagnóstico , Preservação de Sangue , Centrifugação , Criança , Pré-Escolar , Endotoxinas/farmacologia , Heparina/farmacologia , Humanos , Lactente , Pessoa de Meia-Idade , Doenças Parasitárias/diagnóstico , Sepse/diagnóstico , Fatores de Tempo , Viroses/diagnósticoRESUMO
Public concern over chemical hazards is increasing in a context where overall life expectancy has rapidly improved. However, people's expectations of safety continue to exceed the presently attained levels and a mistrust of technological expertise is pervasive. Paradoxically this may arise because the ordinary person has assimilated scientific notions of causality that partially replace religious or magical explanations for accidents and catastrophes. The public's perceptions of risk frequently diverge considerably (in either direction) from the probabilistic risk assessments made by engineers and scientists. Both assessments are usually wrong: reconciliation rather than confrontations should be sought. The public is not 'irrational', it has different reasons and values. A brief view is given of the methodology and main findings of research on perceived risk, both comparative approaches and those where perceptions of a single hazard are explored in detail. Illustrative studies of community attitudes to pesticides, chemical food additives and of people's beliefs about nuclear power are outlined.
Assuntos
Acidentes , Atitude Frente a Saúde , Intoxicação/prevenção & controle , Humanos , Indústrias , Modelos Psicológicos , Praguicidas/intoxicação , Probabilidade , Risco , Segurança , Reino UnidoRESUMO
Given that the best available means have been used to assess the risks arising from a chemical process or product, it is a crucial aspect of management to inform the employees and the public. This task of communicating may fall to industry, government, regulating authority, professional association or an environmental protection group. It requires some understanding of the public's perceptions of the risks involved and an ethical duty to try to modify attitudes judged to be either over-anxious or complacent. There is as yet no structured knowledge on communication about chemical hazards as such. Also, circumstances vary enormously. Hence, this paper deploys the general analytic framework constructed within social psychology and reviews the extensive experimental research (and some field studies) with the aim of providing understanding and some guidance. It considers the basic modelling of attitude change as induced by printed or verbal communications. The variables influencing the effectiveness of communications are divided into: the source (e.g. his/her credibility, power or attractiveness); the message (e.g. emotional versus logical; one-sided versus both-sided arguments); and modality or media effects (e.g. spoken versus written; the mass media; campaigns).
Assuntos
Atitude Frente a Saúde , Comunicação , Intoxicação/prevenção & controle , Acidentes de Trabalho/prevenção & controle , Emoções , Medo , Humanos , Doenças Profissionais/induzido quimicamente , Doenças Profissionais/prevenção & controle , Risco , SegurançaRESUMO
This study examined bidirectional relationships between age at first sexual intercourse and academic goals and achievement. It was hypothesized that lower educational goals and achievement would be associated with initiating sexual intercourse at a younger age, and that initiating sexual activity early would be associated with a decrease in subsequent academic achievement and goals. In longitudinal data spanning 11 years, evidence was found for bidirectional effects. One interpretation of these results is that adolescents with high educational goals and achievement delay having intercourse because of the perceived risks (e.g., pregnancy and sexually transmitted diseases may jeopardize their plans for the future). Conversely, adolescents who engage in sexual intercourse at young ages might undergo a change in attitudes, including reduced interest in academic achievement and goals. The specific educational variables most strongly related to adolescent sexual intercourse in this study differed substantially by race and gender.
Assuntos
Logro , Comportamento do Adolescente , Coito , Educação , Objetivos , Adolescente , Adulto , Negro ou Afro-Americano/estatística & dados numéricos , Fatores Etários , Análise de Variância , Feminino , Humanos , Masculino , Teoria Psicológica , Análise de Regressão , Fatores Sexuais , Estados Unidos , População Branca/estatística & dados numéricosRESUMO
The development of the atmospheric boundary layer (ABL) plays a key role in affecting the variability of atmospheric constituents such as aerosols, greenhouse gases, water vapor, and ozone. In general, the concentration of any tracers within the ABL varies due to the changes in the mixing volume (i.e. ABL depth). In this study, we investigate the impact on the near-surface aerosol concentration in a valley site of 1) the boundary layer dilution due to vertical mixing and 2) changes in the wind patterns. We use a data set obtained during a 10-day field campaign in which a number of remote sensing and in-situ instruments were deployed, including a ground-based aerosol lidar system for monitoring of the ABL top height (zi), a particle counter to determine the number concentration of aerosol particles at eight different size ranges, and tower-based standard meteorological instruments. Results show a clearly visible decreasing trend of the mean daytime zi from 2900 m AGL (above ground level) to 2200 m AGL during a three-day period which resulted in increased near-surface pollutant concentrations. An inverse relationship exists between the zi and the fine fraction (0.3-0.7 µm) accumulation mode particles (AMP) on some days due to the dilution effect in a well-mixed ABL. These days are characterized by the absence of daytime upvalley winds and the presence of northwesterly synoptic-driven winds. In contrast, on the days with an onset of an upvalley wind circulation after the morning transition, the wind-driven local transport mechanism outweighs the ABL-dilution effect in determining the variability of AMP concentration. The interplay between the ABL depth evolution and the onset of the upvalley wind during the morning transition period significantly governs the air quality in a valley and could be an important component in the studies of mountain meteorology and air quality.
Assuntos
Aerossóis/análise , Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Atmosfera/química , Monitoramento Ambiental , Vento , MeteorologiaAssuntos
Derivados de Benzeno/síntese química , Cumarínicos/síntese química , Oligopeptídeos/síntese química , Domínios de Homologia de src , Derivados de Benzeno/química , Cumarínicos/química , Ensaio de Imunoadsorção Enzimática , Ligantes , Modelos Moleculares , Oligopeptídeos/química , Relação Estrutura-AtividadeAssuntos
Neoplasias da Mama/diagnóstico , Educação em Saúde , Palpação , Autocuidado/métodos , Austrália , Feminino , HumanosRESUMO
BACKGROUND: Genistein increases CPT1A, a rate-limiting enzyme in the beta-oxidation pathway, enzyme activity by increasing CPT1A transcription in HepG2 cells and, consequently, suppresses high fat induced obesity in C57BL/6J mice. Genistein and daidzein are the most abundant isoflavones in soy. AIM OF STUDY: To investigate the effect of co-treatment of genistein and L-carnitine on CPT1A enzyme activity and to determine whether daidzein also increases CPT1A activity and to establish a cell line that can be used to screen chemicals to regulate CPT1A transcription. METHODS: The enzyme activities of CPT1A were determined after HepG2 cells were incubated with 10 microM genistein or 10 microM daidzein or 1 mM L-carnitine or in combination with 10 microM genistein and 1 mM L-carnitine or in combination with 10 microM daidzein and 1 mM L-carnitine. The mRNA expression levels of CPT1A were determined by real time PCR method after HepG2 cells were incubated with 10 microM genistein or 10 microM daidzein. A suggested CPT1A promoter region was cloned from human genomic DNA and the CPT1A promoter-luciferase reporter gene construct was made, and the promoter-reporter gene construct was transfected into human hepatoma cell line Huh7. RESULTS: The enzyme activity of CPT1A was at least 2.3- fold higher in L-carnitine and genistein co-treated HepG2 cells than either single-agent treated cells. Daidzein also significantly increased the mRNA expression of CPT1A as well as the enzyme activity of CPT1A. A stable Huh7 cell line, which was selected after Huh7 cells were transfected with CPT1A promoter luciferase reporter gene construct, was characterized by confirming that luciferase activity of the cell line can be regulated by genistein and daidzein as well as clofibrate, a well-known CPT1A mRNA up-regulating drug. CONCLUSIONS: Genistein and daidzein can up-regulate CPT1A enzyme activity through up-regulation of CPT1A transcription. Co-treatment of L-carnitine and genistein additively increases CPT1A enzyme activity in HepG2 cells. A stable Huh7 cell line transfected with the CPT1A promoter luciferase reporter gene was established and characterized.
Assuntos
Carnitina O-Palmitoiltransferase/metabolismo , Carnitina/farmacologia , Regulação Enzimológica da Expressão Gênica , Isoflavonas/farmacologia , Fígado/enzimologia , RNA Mensageiro/metabolismo , Carcinoma Hepatocelular , Carnitina O-Palmitoiltransferase/efeitos dos fármacos , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Genisteína/farmacologia , Humanos , Luciferases/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Glycine max/química , Transcrição Gênica , Transfecção , Células Tumorais Cultivadas , Regulação para CimaRESUMO
BACKGROUND: Polymorphisms of the solute carrier family 11 member 1 (Slc11a1) gene have previously been associated with susceptibility to infectious disease, anti-tumor defenses, and autoimmune diseases. We postulated that polymorphisms of the gene may also be associated with susceptibility to post-transplant lymphoproliferative disease (PTLD), a disease thought to be related to an impaired immune response to Epstein-Barr virus (EBV) in immunosuppressed patients. METHODS: Whole blood samples were obtained from 45 pediatric patients who underwent liver transplantation. Polymerase chain reaction (PCR) was used to amplify a 3' region of the gene that includes an exon 15 single-nucleotide substitution (referred to as D543N) and a 4-bp deletion polymorphism (referred to as 3'-UTR). PCR products were digested using AvaII and FokI restriction enzymes for the D543N and 3'-UTR polymorphisms, respectively. PTLD disease status and EBV virus serum titers of all patients were obtained from hospital records. RESULTS: Six of the 45 pediatric transplant recipients developed PTLD. An association was found between 3'-UTR polymorphisms of Slc11a1 and incidence of PTLD after liver transplantation (P = 0.005). In addition, post-transplant serum EBV titers were higher (P = 0.009) for recipients with certain Slc11a1 polymorphisms. No association was found between the D543N polymorphism and incidence of PTLD. CONCLUSION: 3'-UTR polymorphisms of the Slc11a1 gene appear to be associated with susceptibility to PTLD and the immune response to EBV in pediatric liver transplant recipients. Genotyping of pediatric patients undergoing liver transplantation may enable early identification of patients at high risk for developing high EBV titers and/or PTLD.
Assuntos
Proteínas de Transporte de Cátions/genética , Transplante de Fígado/fisiologia , Transtornos Linfoproliferativos/genética , Regiões 3' não Traduzidas/genética , Adolescente , Proteínas de Transporte de Cátions/imunologia , Criança , Pré-Escolar , Infecções por Vírus Epstein-Barr/sangue , Infecções por Vírus Epstein-Barr/complicações , Infecções por Vírus Epstein-Barr/genética , Infecções por Vírus Epstein-Barr/imunologia , Feminino , Predisposição Genética para Doença , Humanos , Imunidade Celular/imunologia , Lactente , Transplante de Fígado/efeitos adversos , Transplante de Fígado/imunologia , Transtornos Linfoproliferativos/etiologia , Transtornos Linfoproliferativos/imunologia , Transtornos Linfoproliferativos/virologia , Masculino , Polimorfismo GenéticoRESUMO
Nanostructures of self-assembled monolayers (SAMs) are designed and produced using coadsorption and nanografting techniques. Because the structures of these artificially engineered domains are predesigned and well-characterized, a systematic investigation is possible to study the mechanical responses to force modulation under atomic force microscope tips. Force modulation imaging reveals characteristic contrast sensitivity to changes in molecular-level packing, molecule chain lengths, domain boundaries, and surface chemical functionalities in SAMs. By means of actively tuning the driving frequency, the resonances at the tip-surface contact are selectively activated. Therefore, specific surface features, such as the edges of the domains and nanostructures or desired chemical functionalities, can be selectively enhanced in the amplitude images. These observations provide a new and active approach in materials characterization and the study of nanotribology using atomic force microscopy.
RESUMO
A wide variety of proteins have been shown to recognize and bind to specific amino acid sequences on other proteins. These sequences can be readily identified using combinatorial peptide libraries. However, peptides containing these preferred sequences ("consensus sequence peptides") typically display only modest affinities for the consensus sequence-binding site on the intact protein. In this report, we describe a parallel synthesis strategy that transforms consensus sequence peptides into high affinity ligands. The work described herein has focused on the Lck SH2 domain, which binds the consensus peptide acetyl-Tyr(P)-Glu-Glu-Ile-amide with a K(D) of 1.3 micrometer. We employed a strategy that creates a series of spatially focused libraries that challenge specific subsites on the target protein with a diverse array of functionality. The final lead compound identified in this study displayed a 3300-fold higher affinity for the Lck SH2 domain than the starting consensus sequence peptide.
Assuntos
Sequência Consenso , Peptídeos/química , Sequência de Aminoácidos , Ligantes , Proteína Tirosina Quinase p56(lck) Linfócito-Específica/química , Ressonância Magnética Nuclear Biomolecular , Peptídeos/metabolismoRESUMO
The kinetics of the ruthenium-promoted cis,cis to trans,trans isomerization of 1,1,2,2,5,5,6,6-octamethyl-1,2,5,6-tetrasilacycloocta-3,7-diene were investigated. Incubation of a ruthenium alkylidene complex, (Cy(3)P)RuCl(2)(==CHPh)Ru(p-cymene)Cl(2), in CD(2)Cl(2) for 5 days at 40 degrees C afforded a catalytically active ruthenium species that was shown to be responsible for promoting the isomerization. The isomerization was observed to proceed in two steps: (1) conversion of the starting cis,cis isomer to a proposed cis,trans intermediate and (2) subsequent conversion of the intermediate to the product trans,trans isomer. Kinetic studies demonstrated that the two steps are first-order with respect to the concentrations of the cis,cis isomer, the intermediate, and the ruthenium alkylidene complex. The data were further consistent with a mechanism involving bimolecular hydride addition-elimination during the two isomerization steps.