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1.
J Hepatol ; 81(1): 33-41, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38906621

RESUMO

BACKGROUND & AIMS: Oral antiviral therapy with nucleos(t)ide analogues (NAs) for chronic hepatitis B (CHB) is well-tolerated and lifesaving, but real-world data on utilization are limited. We examined rates of evaluation and treatment in patients from the REAL-B consortium. METHODS: This was a cross-sectional study nested within our retrospective multinational clinical consortium (2000-2021). We determined the proportions of patients receiving adequate evaluation, meeting AASLD treatment criteria, and initiating treatment at any time during the study period. We also identified factors associated with receiving adequate evaluation and treatment using multivariable logistic regression analyses. RESULTS: We analyzed 12,566 adult treatment-naïve patients with CHB from 25 centers in 9 countries (mean age 47.1 years, 41.7% female, 96.1% Asian, 49.6% Western region, 8.7% cirrhosis). Overall, 73.3% (9,206 patients) received adequate evaluation. Among the adequately evaluated, 32.6% (3,001 patients) were treatment eligible by AASLD criteria, 83.3% (2,500 patients) of whom were initiated on NAs, with consistent findings in analyses using EASL criteria. On multivariable logistic regression adjusting for age, sex, cirrhosis, and ethnicity plus region, female sex was associated with adequate evaluation (adjusted odds ratio [aOR] 1.13, p = 0.004), but female treatment-eligible patients were about 50% less likely to initiate NAs (aOR 0.54, p <0.001). Additionally, the lowest evaluation and treatment rates were among Asian patients from the West, but no difference was observed between non-Asian patients and Asian patients from the East. Asian patients from the West (vs. East) were about 40-50% less likely to undergo adequate evaluation (aOR 0.60) and initiate NAs (aOR 0.54) (both p <0.001). CONCLUSIONS: Evaluation and treatment rates were suboptimal for patients with CHB in both the East and West, with significant sex and ethnic disparities. Improved linkage to care with linguistically competent and culturally sensitive approaches is needed. IMPACT AND IMPLICATIONS: Significant sex and ethnic disparities exist in hepatitis B evaluation and treatment, with female treatment-eligible patients about 50% less likely to receive antiviral treatment and Asian patients from Western regions also about 50% less likely to receive adequate evaluation or treatment compared to Asians from the East (there was no significant difference between Asian patients from the East and non-Asian patients). Improved linkage to care with linguistically competent and culturally sensitive approaches is needed.


Assuntos
Antivirais , Disparidades em Assistência à Saúde , Hepatite B Crônica , Humanos , Feminino , Masculino , Antivirais/uso terapêutico , Estudos Transversais , Pessoa de Meia-Idade , Estudos Retrospectivos , Hepatite B Crônica/tratamento farmacológico , Hepatite B Crônica/etnologia , Adulto , Disparidades em Assistência à Saúde/estatística & dados numéricos , Disparidades em Assistência à Saúde/etnologia , Fatores Sexuais , Etnicidade/estatística & dados numéricos , Saúde Global
2.
Rhinology ; 62(1): 111-118, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-37865935

RESUMO

BACKGROUND: Serum eosinophil cationic protein (ECP) levels affect the surgical outcome of chronic rhinosinusitis (CRS) with nasal polyps. Primary CRS can be classified into type 2 (T2) and non-T2. We aimed to differentiate the role of serum ECP levels in surgical outcomes between the distinct endotypes of primary CRS. METHODS: We prospectively enrolled patients with bilateral primary CRS who underwent surgical treatment with postoperative follow-up for at least 12 months. Endotyping and serum parameter measurements were completed within 1 week before surgery. RESULTS: In total, 113 patients were enrolled, including 65 with T2 CRS and 48 with non-T2 CRS. Patients in the T2 CRS group with uncontrolled CRS had significantly higher serum ECP levels than those in patients in the non-T2 CRS group. An optimal cut-off value was obtained at 17.0 λg/L using the receiver operating characteristic curve, attaining a sensitivity of 91.7% and specificity of 56.6%. Multivariate logistic regression analysis showed that a higher serum ECP level was an independent factor for postoperative uncontrolled disease. The hazard ratio was 11.3 for the T2 group, with serum ECP levels over 17.0 λg/L. In the non-T2 group, no parameters were significantly correlated with postoperative uncontrolled CRS. CONCLUSIONS: Serum ECP levels appear to be a feasible predictor of postoperative uncontrolled disease in patients with T2 CRS as preoperative serum ECP levels >17.0 λg/L in these patients have an approximately 16.7-fold increased risk of postoperative uncontrolled disease and should be closely monitored.


Assuntos
Pólipos Nasais , Rinite , Rinossinusite , Sinusite , Humanos , Proteína Catiônica de Eosinófilo , Rinite/etiologia , Doença Crônica , Sinusite/complicações , Pólipos Nasais/complicações , Pólipos Nasais/cirurgia , Eosinófilos
3.
Mol Psychiatry ; 23(2): 422-433, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-27843151

RESUMO

The lack of reliable measures of alcohol intake is a major obstacle to the diagnosis and treatment of alcohol-related diseases. Epigenetic modifications such as DNA methylation may provide novel biomarkers of alcohol use. To examine this possibility, we performed an epigenome-wide association study of methylation of cytosine-phosphate-guanine dinucleotide (CpG) sites in relation to alcohol intake in 13 population-based cohorts (ntotal=13 317; 54% women; mean age across cohorts 42-76 years) using whole blood (9643 European and 2423 African ancestries) or monocyte-derived DNA (588 European, 263 African and 400 Hispanic ancestry) samples. We performed meta-analysis and variable selection in whole-blood samples of people of European ancestry (n=6926) and identified 144 CpGs that provided substantial discrimination (area under the curve=0.90-0.99) for current heavy alcohol intake (⩾42 g per day in men and ⩾28 g per day in women) in four replication cohorts. The ancestry-stratified meta-analysis in whole blood identified 328 (9643 European ancestry samples) and 165 (2423 African ancestry samples) alcohol-related CpGs at Bonferroni-adjusted P<1 × 10-7. Analysis of the monocyte-derived DNA (n=1251) identified 62 alcohol-related CpGs at P<1 × 10-7. In whole-blood samples of people of European ancestry, we detected differential methylation in two neurotransmitter receptor genes, the γ-Aminobutyric acid-A receptor delta and γ-aminobutyric acid B receptor subunit 1; their differential methylation was associated with expression levels of a number of genes involved in immune function. In conclusion, we have identified a robust alcohol-related DNA methylation signature and shown the potential utility of DNA methylation as a clinically useful diagnostic test to detect current heavy alcohol consumption.


Assuntos
Consumo de Bebidas Alcoólicas/genética , Transtornos Relacionados ao Uso de Álcool/genética , Metilação de DNA/efeitos dos fármacos , Adulto , Idoso , Consumo de Bebidas Alcoólicas/metabolismo , Transtornos Relacionados ao Uso de Álcool/metabolismo , Biomarcadores/sangue , População Negra/genética , Ilhas de CpG/genética , Epigênese Genética , Etanol/sangue , Etanol/metabolismo , Feminino , Estudo de Associação Genômica Ampla , Humanos , Masculino , Pessoa de Meia-Idade , População Branca/genética
4.
Clin Genet ; 92(2): 150-157, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28233300

RESUMO

BACKGROUND: Mutations in the DNAJB6 gene have been identified as a rare cause of dominantly inherited limb-girdle muscular dystrophy or distal-onset myopathy. MATERIALS AND METHODS: Exome sequencing was performed to investigate a Taiwanese family with a dominantly inherited distal-onset myopathy. Functional effects of the causal mutation were investigated in vitro. RESULTS: Exome sequencing of the two affected individuals in this family identified a heterozygous mutation, c.287C>T (p.Pro96Leu) in the DNAJB6 gene, which co-segregated with the myopathy within all 12 family members. Notably, this mutation is novel and localizes within the glycine and phenylalanine-rich (G/F) domain and alters an amino acid residue previously reported with a different mutation. Furthermore, immunofluorescence analyses and filter trap assay demonstrated that the c.287C>T (p.Pro96Leu) mutation possessed a dominant negative effect on the anti-aggregation function of DNAJB6 protein. CONCLUSION: This study expands the molecular spectrum of DNAJB6 mutations and also emphasizes the pathogenic role of DNAJB6 dysfunction in distal-onset myopathy.


Assuntos
Miopatias Distais/genética , Predisposição Genética para Doença , Proteínas de Choque Térmico HSP40/genética , Chaperonas Moleculares/genética , Proteínas do Tecido Nervoso/genética , Adulto , Idade de Início , Miopatias Distais/diagnóstico por imagem , Miopatias Distais/fisiopatologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Músculo Esquelético/diagnóstico por imagem , Músculo Esquelético/fisiopatologia , Mutação , Mutação de Sentido Incorreto/genética , Sequenciamento do Exoma
5.
Clin Epigenetics ; 13(1): 36, 2021 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-33593402

RESUMO

BACKGROUND: Smoking remains one of the leading preventable causes of death. Smoking leaves a strong signature on the blood methylome as shown in multiple studies using the Infinium HumanMethylation450 BeadChip. Here, we explore novel blood methylation smoking signals on the Illumina MethylationEPIC BeadChip (EPIC) array, which also targets novel CpG-sites in enhancers. METHOD: A smoking-methylation meta-analysis was carried out using EPIC DNA methylation profiles in 1407 blood samples from four UK population-based cohorts, including the MRC National Survey for Health and Development (NSHD) or 1946 British birth cohort, the National Child Development Study (NCDS) or 1958 birth cohort, the 1970 British Cohort Study (BCS70), and the TwinsUK cohort (TwinsUK). The overall discovery sample included 269 current, 497 former, and 643 never smokers. Replication was pursued in 3425 trans-ethnic samples, including 2325 American Indian individuals participating in the Strong Heart Study (SHS) in 1989-1991 and 1100 African-American participants in the Genetic Epidemiology Network of Arteriopathy Study (GENOA). RESULTS: Altogether 952 CpG-sites in 500 genes were differentially methylated between smokers and never smokers after Bonferroni correction. There were 526 novel smoking-associated CpG-sites only profiled by the EPIC array, of which 486 (92%) replicated in a meta-analysis of the American Indian and African-American samples. Novel CpG sites mapped both to genes containing previously identified smoking-methylation signals and to 80 novel genes not previously linked to smoking, with the strongest novel signal in SLAMF7. Comparison of former versus never smokers identified that 37 of these sites were persistently differentially methylated after cessation, where 16 represented novel signals only profiled by the EPIC array. We observed a depletion of smoking-associated signals in CpG islands and an enrichment in enhancer regions, consistent with previous results. CONCLUSION: This study identified novel smoking-associated signals as possible biomarkers of exposure to smoking and may help improve our understanding of smoking-related disease risk.


Assuntos
Estudo de Associação Genômica Ampla/métodos , Família de Moléculas de Sinalização da Ativação Linfocitária/genética , Fumar Tabaco/sangue , Fumar Tabaco/genética , Negro ou Afro-Americano/genética , Idoso , Estudos de Casos e Controles , Estudos de Coortes , Ilhas de CpG , Metilação de DNA , Exposição Ambiental/efeitos adversos , Epigênese Genética , Epigenoma , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Fumantes/estatística & dados numéricos , Fumar Tabaco/etnologia , Reino Unido/epidemiologia , População Branca/genética , Indígena Americano ou Nativo do Alasca/genética
6.
Ann Rheum Dis ; 68(7): 1213-9, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18678579

RESUMO

OBJECTIVE: To identify the position of a gout susceptibility gene. METHODS: A genome-wide scan was performed using 382 random polymorphic microsatellite markers spread across 22 autosomes in a Taiwanese family with gout to screen for the gout susceptibility genetic marker. Its association with gout by 33 single nucleotide polymorphisms (SNP) in 148 matched case-control subjects was confirmed. The family with gout comprised eight patients with gout and 10 gout-free subjects; case-control subjects were 74 male patients with gout and 74 healthy controls matched by age. RESULTS: Analysis of the genome-wide scan results by a non-parametric linkage method found that chromosome 4q21 contains a locus significantly linked with gout (D4S3243 at 81 289 553 bp; p = 0.004; LOD score = 5.13). In SNP genotyping analysis at the neighbourhood regions of marker D4S3243 for the case-control subjects, the polymorphisms rs7688672 and rs6837293, located on the cGMP-dependent protein kinase II (cGK II) gene, were found to relate significantly to gout disease in a recessive model after adjustment of hyperuricaemia (OR = 2.89, 95% CI 1.19 to 7.02 and OR = 2.72, 95% CI 1.13 to 6.54, respectively). CONCLUSIONS: This study suggests that the cGK II gene on chromosome 4q21 is most likely to harbour gout disease independently of hyperuricaemia and is inherited recessively.


Assuntos
Cromossomos Humanos Par 21/genética , Proteínas Quinases Dependentes de GMP Cíclico/genética , Predisposição Genética para Doença/genética , Gota/genética , Adulto , Estudos de Casos e Controles , Proteína Quinase Dependente de GMP Cíclico Tipo II , Humanos , Escore Lod , Masculino , Linhagem , Polimorfismo Genético
7.
Rheumatology (Oxford) ; 47(5): 617-21, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18356176

RESUMO

OBJECTIVES: To investigate the associations between gout tophus and polymorphisms 869T/C and -509C/T in TGF-beta1 gene. METHODS: The polymorphisms 869T/C and -509C/T were determined in 73 gout patients and 114 healthy controls among male Taiwanese using the PCR-restriction fragment length polymorphism method. Each patient was matched with 1-2 controls by age within 1-2 yrs. The tophus number was measured from all the patients' arms and legs. RESULTS: Neither 869T/C nor -509C/T showed a significant association between patients and controls in the proportions of genotypes, allele frequency or dominant and recessive models. The mean number of tophi for all patients was 1.53 +/- 3.44, showing a significant difference in distribution among the genotypes at polymorphism 869T/C (P = 0.006), but not those in polymorphism -509C/T (P > 0.05). Those carrying genotype CC at polymorphism 869T/C have a mean number of tophi 0.35 (+/- 1.11), which is significantly lower than those carrying genotype TT (3.73 +/- 4.67; P < 0.05). Those with genotype TT at polymorphism 869T/C also had 11.06 times the likelihood of having at least one tophus compared with the genotype CC after adjustment of hyperuricaemia (95% CI = 1.84, 66.36; P = 0.009). However, except for the tophus number, these two polymorphisms did not show any significant association with the clinical characteristics or biochemical markers. CONCLUSIONS: The polymorphism 869T/C in TGF-beta1 gene has a significant association with the occurrence of tophus in gout patients.


Assuntos
Gota/patologia , Articulações/patologia , Polimorfismo Genético , Fator de Crescimento Transformador beta1/genética , Adulto , Análise de Variância , Estudos de Casos e Controles , Estudos Transversais , Frequência do Gene , Predisposição Genética para Doença , Genótipo , Haplótipos , Humanos , Desequilíbrio de Ligação , Masculino , Pessoa de Meia-Idade , Polimorfismo de Fragmento de Restrição
8.
Clin Exp Rheumatol ; 26(5): 841-7, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-19032817

RESUMO

OBJECTIVE: To explore the associations between the polymorphisms and protein levels of interleukin-6 (IL-6) gene and gout disease. METHODS: A total of 120 male gout patients and 184 healthy controls were enrolled. Each patient was matched with 1-2 gout-free controls by age within three years. Four polymorphisms in the promoter of IL-6 gene, including -597G/A, -572C/G, -373A(m)T(n), and -174G/C, and the IL-6 levels were analyzed. The clinical characteristics and biochemical markers in plasma were measured, including age of gout onset, duration of gout history, tophus number, gout attack frequency, uric acid, total cholesterol, triglycerides and creatinine. RESULTS: The mean IL-6 level for gout patients was 9.80 (+/-11.76 pg/ml) which showed no significant difference from the controls (7.06+/-7.58 pg/ml, p=0.230). When the IL-6 levels were dichotomized according to the median value (5 pg/ml), there were significantly higher proportions of the gout patients (59.66%) than controls (44%) with high IL-6 levels (OR=1.88, 95% CI=1.17-3.02, p=0.008). Unique genotype was found at polymorphisms -174G/C and -597G/A. Neither the polymorphisms -572C/G nor -373A(m)T(n) in the genotype or allele distributions showed a significant association related to clinical characteristics, biochemical markers, IL-6 levels or gout disease (all p>0.05). CONCLUSIONS: Those with gout disease have greater proportions of high IL-6 levels in plasma than controls, and there is no significant association between the four polymorphisms in the promoter region of IL-6 gene and gout disease.


Assuntos
Gota/genética , Interleucina-6/genética , Polimorfismo de Nucleotídeo Único/genética , Regiões Promotoras Genéticas/genética , Adulto , Idoso , Estudos de Casos e Controles , Frequência do Gene , Predisposição Genética para Doença/genética , Humanos , Interleucina-6/sangue , Masculino , Pessoa de Meia-Idade , Razão de Chances
9.
Aliment Pharmacol Ther ; 48(1): 44-54, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29797518

RESUMO

BACKGROUND: Hepatitis B virus (HBV) is the leading cause of hepatocellular carcinoma (HCC) worldwide. It remains incompletely understood in the real world how anti-viral therapy affects survival after HCC diagnosis. METHODS: This was an international multicentre cohort study of 2518 HBV-related HCC cases diagnosed between 2000 and 2015. Cox proportional hazards models were utilised to estimate hazard ratios (HR) with 95% (CI) for anti-viral therapy and cirrhosis on patients' risk of death. RESULTS: Approximately, 48% of patients received anti-viral therapy at any time, but only 17% were on therapy at HCC diagnosis (38% at US centres, 11% at Asian centres). Anti-viral therapy would have been indicated for >60% of the patients not on anti-viral therapy based on American criteria. Patients with cirrhosis had lower 5-year survival (34% vs 46%; P < 0.001) while patients receiving anti-viral therapy had increased 5-year survival compared to untreated patients (42% vs 25% with cirrhosis and 58% vs 36% without cirrhosis; P < 0.001 for both). Similar findings were seen for other patient subgroups by cancer stages and cancer treatment types. Anti-viral therapy was associated with a decrease in risk of death, whether started before or after HCC diagnosis (adjusted HR 0.62 and 0.79, respectively; P < 0.001). CONCLUSIONS: Anti-viral therapy improved overall survival in patients with HBV-related HCC across cancer stages and treatment types but was underutilised at both US and Asia centres. Expanded use of anti-viral therapy in HBV-related HCC and better linkage-to-care for HBV patients are needed.


Assuntos
Antivirais/uso terapêutico , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/mortalidade , Hepatite B/tratamento farmacológico , Hepatite B/mortalidade , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/mortalidade , Padrões de Prática Médica/estatística & dados numéricos , Idoso , Ásia/epidemiologia , Carcinoma Hepatocelular/virologia , Estudos de Coortes , Uso Indevido de Medicamentos/estatística & dados numéricos , Feminino , Mau Uso de Serviços de Saúde/estatística & dados numéricos , Hepatite B/complicações , Vírus da Hepatite B/fisiologia , Humanos , Prescrição Inadequada/estatística & dados numéricos , Cirrose Hepática/complicações , Cirrose Hepática/tratamento farmacológico , Cirrose Hepática/mortalidade , Cirrose Hepática/virologia , Neoplasias Hepáticas/virologia , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Análise de Sobrevida , Estados Unidos/epidemiologia
10.
J Mater Chem B ; 3(5): 814-823, 2015 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-32262172

RESUMO

A-B block copolymer micelles comprised of thermoresponsive hydrophilic PNIPAAm (poly(N-isopropylacrylamide)) coronae and hydrophobic PNP (poly(N-acryloyl-2-pyrrolidone)), PMNP (poly(N-acryloyl-5-methoxy-2-pyrrolidone)), or PBNP (poly(N-acryloyl-5-butoxy-2-pyrrolidone)) cores were examined to identify how systematic adjustments to core-segment structure affect micellar physicochemical properties, drug loading efficiency (DLE), and thermoresponsive drug release among these novel systems. Critical micelle concentrations (CMCs) were found to decrease by two orders of magnitude in the order of PNIPAAm-PNP, PNIPAAm-PMNP, and PNIPAAm-PBNP indicating that minor modifications to the pyrrolidone scaffold significantly affect its hydrophobic character. Moreover, the structural modifications were also found to influence micelle size and intermicellar aggregation that occurs above the lower critical solution temperature (LCST). In line with the CMC data, DLE values of doxorubicin-loaded (i.e., DOX-loaded) micelles increase in the order of PNIPAAm-PNP, PNIPAAm-PMNP, and PNIPAAm-PBNP, a trend attributed to enhanced cohesive forces (i.e. London dispersion forces) between DOX and core as the latter becomes more hydrophobic. When heated above the LCST, DOX release decreases in the order of PNIPAAm-PNP, PNIPAAm-PMNP, and PNIPAAm-PBNP suggesting that release processes are impeded by the cohesive forces responsible for efficient encapsulation. Finally, cytotoxicity assays performed above the LCST reveal that DOX-loaded micelles are as cytotoxic as the free drug in formulations where DOX concentrations are equivalent.

11.
Rheumatology (Oxford) ; 46(11): 1662-6, 2007 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17938134

RESUMO

OBJECTIVE: To investigate the associations between polymorphisms in the promoter of the tumour necrosis factor-alpha (TNF-alpha) gene and gout. METHODS: The polymorphisms -308G/A and -863C/A in the TNF-alpha gene were determined in 106 gout patients and 159 healthy controls among male Taiwanese using the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) method. The biochemical markers, including Glutamic-oxaloacetic transaminase (GOT), Glutamic-pyruvic transaminase (GPT), uric acid, creatinine, total cholesterol (TC), triglycerides (TG), body mass index (BMI) and hypertension, as well as alcohol consumption were measured. RESULTS: The gout patients had 9.43% (10/106) with genotype AA at polymorphism -863C/A showing a significantly higher fraction than controls (0.63%; 1/159, P < 0.001). The crude results also showed that the gout patients had significantly higher portions of abnormal GOT, GPT, creatinine, TC, TG, alcohol consumption, hypertension and hyperuricaemia than controls (P < 0.05), but the -308G/A, BMI and genotype CA at -863C/A did not show the same significant difference (P > 0.05). After adjustment by a stepwise logistic regression method, the hyperuricaemia, creatinine, GPT, TG and alcohol consumption as well as genotype AA at polymorphism -863C/A were found to be significantly associated with gout. CONCLUSION: The genotype AA at polymorphism -863C/A in a recessive model showed a significant association with developing gout independent of hyperuricaemia, abnormal creatinine, higher TG, GPT and alcohol consumption.


Assuntos
Gota/genética , Polimorfismo Genético , Fator de Necrose Tumoral alfa/genética , Adulto , Idoso , Alanina Transaminase/sangue , Consumo de Bebidas Alcoólicas/efeitos adversos , Biomarcadores/sangue , Creatinina/sangue , Estudos Transversais , Predisposição Genética para Doença , Genótipo , Gota/sangue , Gota/etiologia , Humanos , Hiperuricemia/complicações , Masculino , Pessoa de Meia-Idade , Regiões Promotoras Genéticas/genética , Triglicerídeos/sangue
12.
Epidemiol Infect ; 133(6): 1119-22, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16274510

RESUMO

Between March and July 2003, 671 cases of severe acute respiratory syndrome (SARS) were diagnosed in Taiwan with a total of 84 fatalities. After the epidemic, a serological survey was conducted involving the asymptomatic household contacts. Household contacts of 13 index patients were enrolled in the study. Contact history and clinical symptoms of the household contacts were recorded by standardized questionnaires. Blood samples of patients and household contacts were collected at least 28 days after symptom onset in the index patients or household exposure in the contacts for SARS-associated coronavirus (SARS-CoV) IgG testing. On the basis of this investigation, 29 persons (25 adults and 4 children) were identified as having had unprotected exposure to the index cases before infection-control practices were implemented. Laboratory evaluation of clinical specimens showed no evidence of transmission of SARS-CoV infection to any contacts. This investigation demonstrated that subclinical transmission among household contacts was low in the described setting.


Assuntos
Anticorpos Antivirais/sangue , Síndrome Respiratória Aguda Grave/transmissão , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/imunologia , Adulto , Busca de Comunicante , Feminino , Humanos , Imunoglobulina G/sangue , Masculino , Pessoa de Meia-Idade , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/isolamento & purificação , Estudos Soroepidemiológicos , Síndrome Respiratória Aguda Grave/epidemiologia
13.
Protein Expr Purif ; 23(3): 432-9, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11722180

RESUMO

Dehydrodolichyl diphosphate synthase (DDPPs) catalyzes the sequential condensation of isopentenyl diphosphate with farnesyl diphosphate to synthesize long-chain dehydrodolichyl diphosphate, which serves as a precursor of glycosyl carrier in glycoprotein biosynthesis in eukaryotes. To perform kinetic and structural studies of DDPPs, we have expressed yeast DDPPs using Escherichia coli as the host cell. Thioredoxin and His tag were utilized to increase the solubility of the recombinant protein and facilitate its purification using Ni-nitrilotriacetic acid (NTA) column. The protein was overexpressed in E. coli but mostly existed in pellet in the absence of detergent. The low quantity of soluble DDPPs was purified using Ni-NTA, Mono Q anion-exchange, and size-column chromatographies. The protein in the pellet was solubilized with 7 M urea and purified using Ni-NTA under denaturing condition. The protein refolding was achieved via the stepwise dialysis to remove the denaturant in the presence of 6 mM beta-mercaptoethanol. Detergent n-octyl-beta-d-glucopyranoside and Triton X-100 increased the solubility of the DDPPs so that refolding can be performed at higher protein concentration. Alternatively, on-column refolding was carried out in a single step to obtain the active protein in large quantities. beta-Mercaptoethanol and Triton were both required in this quick refolding process. The kinetic studies indicated that the soluble and refolded DDPPs have comparable activities (k(cat) = 2 x 10(-4) s(-1)). Unlike its bacterial homologue, undecaprenyl diphosphate synthase, yeast DDPPs activity was not enhanced by Triton.


Assuntos
Alquil e Aril Transferases/química , Alquil e Aril Transferases/genética , Escherichia coli/genética , Leveduras/enzimologia , Alquil e Aril Transferases/isolamento & purificação , Alquil e Aril Transferases/metabolismo , Detergentes/química , Fosfatos de Dolicol/metabolismo , Expressão Gênica , Histidina/metabolismo , Corpos de Inclusão/metabolismo , Cinética , Dobramento de Proteína , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/isolamento & purificação , Proteínas Recombinantes de Fusão/metabolismo , Solubilidade , Trombina/metabolismo , Transformação Genética
14.
J Biol Chem ; 276(50): 47474-82, 2001 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-11581264

RESUMO

The Escherichia coli undecaprayl-pyrophosphate synthase (UPPs) structure has been solved using the single wavelength anomalous diffraction method. The putative substrate-binding site is located near the end of the betaA-strand with Asp-26 playing a critical catalytic role. In both subunits, an elongated hydrophobic tunnel is found, surrounded by four beta-strands (betaA-betaB-betaD-betaC) and two helices (alpha2 and alpha3) and lined at the bottom with large residues Ile-62, Leu-137, Val-105, and His-103. The product distributions formed by the use of the I62A, V105A, and H103A mutants are similar to those observed for wild-type UPPs. Catalysis by the L137A UPPs, on the other hand, results in predominantly the formation of the C(70) polymer rather than the C(55) polymer. Ala-69 and Ala-143 are located near the top of the tunnel. In contrast to the A143V reaction, the C(30) intermediate is formed to a greater extent and is longer lived in the process catalyzed by the A69L mutant. These findings suggest that the small side chain of Ala-69 is required for rapid elongation to the C(55) product, whereas the large hydrophobic side chain of Leu-137 is required to limit the elongation to the C(55) product. The roles of residues located on a flexible loop were investigated. The S71A, N74A, or R77A mutants displayed 25-200-fold decrease in k(cat) values. W75A showed an 8-fold increase of the FPP K(m) value, and 22-33-fold increases in the IPP K(m) values were observed for E81A and S71A. The loop may function to bridge the interaction of IPP with FPP, needed to initiate the condensation reaction and serve as a hinge to control the substrate binding and product release.


Assuntos
Alquil e Aril Transferases/química , Escherichia coli/química , Escherichia coli/enzimologia , Alanina/química , Alquil e Aril Transferases/genética , Alquil e Aril Transferases/metabolismo , Sequência de Aminoácidos , Animais , Ácido Aspártico/química , Sítios de Ligação , Catálise , Cristalografia por Raios X , Detergentes/farmacologia , Dimerização , Cinética , Bicamadas Lipídicas/metabolismo , Modelos Biológicos , Modelos Moleculares , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Mutação , Octoxinol/farmacologia , Ligação Proteica , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Homologia de Sequência de Aminoácidos , Fatores de Tempo
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