Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 31
Filtrar
Más filtros

Bases de datos
Tipo del documento
Intervalo de año de publicación
1.
Zhonghua Gan Zang Bing Za Zhi ; 31(7): 692-697, 2023 Jul 20.
Artículo en Zh | MEDLINE | ID: mdl-37580250

RESUMEN

Objective: To analyze the occurrence of recompensation conditions in patients with chronic hepatitis B virus-related decompensated cirrhosis after entecavir antiviral therapy. Methods: Patients with hepatitis B virus-related decompensated cirrhosis with ascites as the initial manifestation were prospectively enrolled. Patients who received entecavir treatment for 120 weeks and were followed up every 24 weeks (including clinical endpoint events, hematological and imaging indicators, and others) were calculated for recompensation rates according to the Baveno VII criteria. Measurement data were compared using the Student t-test or Mann-Whitney U test between groups. Categorical data were compared by the χ (2) test or Fisher's exact probability method between groups. Results: 283 of the 320 enrolled cases completed the 120-week follow-up, and 92.2% (261/283) achieved a virological response (HBV DNA 20 IU/ml). Child-Pugh and MELD scores were significantly improved after treatment (8.33 ± 1.90 vs. 5.77 ± 1.37, t = 12.70, P < 0.001; 13.37 ± 4.44 vs. 10.45 ± 4.58, t = 5.963, P < 0.001). During the 120-week follow-up period, 14 cases died, two received liver transplants, 19 developed hepatocellular cancer, 11 developed gastroesophageal variceal bleeding, and four developed hepatic encephalopathy. 60.4% (171/283) (no decompensation events occurred for 12 months) and 56.2% (159/283) (no decompensation events occurred for 12 months and improved liver function) of the patients had achieved clinical recompensation within 120 weeks. Patients with baseline MELD scores > 15 after active antiviral therapy achieved higher recompensation than patients with baseline MELD scores ≤15 [50/74 (67.6%) vs. 109/209 (52.2%), χ (2) = 5.275, P = 0.029]. Conclusion: Antiviral therapy can significantly improve the prognosis of patients with hepatitis B virus-related decompensated cirrhosis. The majority of patients (56.2%) had achieved recompensation. Patients with severe disease did not have a lower probability of recompensation at baseline than other patients.


Asunto(s)
Várices Esofágicas y Gástricas , Hepatitis B Crónica , Hepatitis B , Humanos , Antivirales/efectos adversos , Várices Esofágicas y Gástricas/complicaciones , Hemorragia Gastrointestinal/complicaciones , Hepatitis B/tratamiento farmacológico , Virus de la Hepatitis B/genética , Hepatitis B Crónica/complicaciones , Hepatitis B Crónica/tratamiento farmacológico , Cirrosis Hepática/complicaciones , Resultado del Tratamiento
2.
J Viral Hepat ; 24(3): 246-252, 2017 03.
Artículo en Inglés | MEDLINE | ID: mdl-28025872

RESUMEN

There are little data on the timing of initiating lamivudine therapy for preventing transmission of hepatitis B in highly viremic mothers. Between May 2008 and January 2015, we retrospectively enrolled mothers with HBV DNA >6 log10  copies/mL who received lamivudine during pregnancy, and we compared them to untreated mothers. The primary measurement was the vertical transmission rate. The secondary outcomes were the mothers' and infants' safety. Among 249 consecutive mothers enrolled, 66 and 94 received lamivudine during the second and third trimesters, respectively, and 89 were untreated. At delivery, maternal mean HBV DNA levels were significantly lower in mothers who received lamivudine (4.45 log10; vs 7.16 log10  copies/mL; P<.001). Lamivudine treatment was well tolerated. However, early treatment during the second trimester did not significantly increase the percentage of mothers achieving HBV DNA levels of <6 log10  copies/mL compared to those treated during the third trimester (98.5% vs 94.7%; P=.40). At the age of 28 weeks, the vertical transmission rates were significantly lower in the lamivudine-treated mothers vs in the untreated mothers (0% [0/160] vs 5.62% [5/89]; P<.001), but the rates were similar when comparing the two subgroups treated with lamivudine (0% [0/66] vs 0% [0/94], P>.05). The birth defect rates and mothers' and infants' adverse events were similar among the groups. Lamivudine treatment initiated in the second or third trimester for mothers with HBV DNA levels below 9 log10  copies/mL was equally safe and effective in preventing vertical transmission. Thus, lamivudine should be deferred until the third trimester to minimize foetal exposure and drug resistance.


Asunto(s)
Antivirales/administración & dosificación , Hepatitis B Crónica/tratamiento farmacológico , Hepatitis B Crónica/transmisión , Transmisión Vertical de Enfermedad Infecciosa/prevención & control , Lamivudine/administración & dosificación , Complicaciones Infecciosas del Embarazo/tratamiento farmacológico , Adulto , Antivirales/efectos adversos , Anomalías Congénitas/epidemiología , ADN Viral/sangre , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/epidemiología , Femenino , Hepatitis B Crónica/prevención & control , Humanos , Recién Nacido , Lamivudine/efectos adversos , Masculino , Embarazo , Segundo Trimestre del Embarazo , Tercer Trimestre del Embarazo , Estudios Retrospectivos , Factores de Tiempo , Resultado del Tratamiento , Carga Viral , Adulto Joven
3.
J Viral Hepat ; 22(8): 675-81, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25417914

RESUMEN

Entecavir (ETV) is a first-line antiviral therapy for treating chronic hepatitis B (CHB); however, some patients have suboptimal response to ETV. Currently, there are limited data on how to approach these patients. Therefore, our aim was to compare the effectiveness of two alternate therapies--tenofovir (TDF) monotherapy and combination therapy of ETV+TDF--in CHB patients with ETV partial virological response. We conducted a retrospective study of 68 patients who had partial virological response to ETV, defined as having detectable HBV DNA following at least 12 months of ETV, and were switched to TDF monotherapy (n = 25) or ETV+TDF (n = 43). Patients were seen in seven US liver/community-based clinics and started on ETV between 2005 and 2009. The majority of patients were male; the vast majority were Asian and had positive hepatitis B e antigen (HBeAg). Patients in both groups had similar pretreatment characteristics. Complete viral suppression (CVS) rates with TDF monotherapy and ETV+TDF were similar after 6 months (71% vs 83%, P = 0.23) and 12 months (86% vs 84%, P = 0.85), and there was no statistically significant difference in CVS rates even when only patients with higher HBV DNA levels at switch (>1000 IU/mL) were evaluated. Multivariate analysis indicated that ETV+TDF was not an independent predictor of CVS compared to TDF monotherapy (OR = 1.19, P = 0.63). In conclusion, TDF monotherapy and ETV+TDF are comparable in achieving CVS in CHB patients with partial virological response to ETV. Long-term alternate therapy with one pill (TDF monotherapy) vs two pills (ETV+TDF) could lead to lower nonadherence rates and better treatment outcomes.


Asunto(s)
Antivirales/uso terapéutico , Guanina/análogos & derivados , Hepatitis B Crónica/tratamiento farmacológico , Tenofovir/uso terapéutico , Adulto , Anciano , ADN Viral/sangre , Quimioterapia/métodos , Femenino , Guanina/uso terapéutico , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Resultado del Tratamiento , Carga Viral , Adulto Joven
4.
J Viral Hepat ; 19(3): 213-9, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22329376

RESUMEN

Both entecavir (ETV) and tenofovir (TDF) are potent antiviral agents for hepatitis B virus (HBV). Suboptimal response (SOR) following antiviral therapy is associated with an increased risk of subsequent treatment failure and viral resistance. It remains unclear whether switching to TDF is a reasonable approach in patients with SOR to ETV treatment. This study was aimed to determine how HBV patients with SOR to ETV respond to TDF monotherapy. Data of patients with SOR to ETV (failure to achieve >1 log(10) HBV-DNA reduction during the last 24 weeks of ETV treatment) who were switched to TDF monotherapy during 2005 and 2010 were reviewed. Treatment adherence was assessed by pill-count. Fourteen patients (2.9%) were identified from a total cohort of 482 ETV-treated patients. All 14 patients were Chinese and were infected with HBV genotype C (71%) or B (29%). Nine patients were men, and the median age was 41.5 years (19-64). Twelve were treatment naïve (one lamivudine- and one peginterferon-experienced patient); 85.7% were HBeAg positive. The median baseline HBV-DNA was 7.55 (5.30-9.40) log(10) copies/mL, and 57% had abnormal serum alanine aminotransferase (ALT) levels. Precore and/or basal core promoter mutations were detected in four patients, whereas no genotypic resistance was detected at baseline and before switching to TDF. The median duration of ETV treatment was 64.5 (26-126) weeks. The median HBV-DNA at the time of switching to TDF was 3.69 (3.00-4.90) log(10) copies/mL. The median HBV-DNA reduction from baseline and during the last 6-month observation period prior to switching to TDF was 4.04 (0.51-6.06) log(10) and 0.43 (-0.09-1.13) log(10) copies/mL, respectively. After the switching to TDF, all 14 patients (100%) achieved undetectable HBV-DNA and ALT normalization within a median duration of 30 weeks. In 12 patients who were HBeAg positive, HBeAg seroconversion was observed in two patients after TDF treatment of 75- and 84-weeks duration. There was no virological breakthrough observed after switching to TDF with a median follow-up period of 50 (24-160) weeks. TDF treatment was safe and well tolerated. In conclusion, suboptimal response to ETV is rare (approximately 3%). TDF monotherapy is safe and very effective in the management of HBV patients with SOR to ETV.


Asunto(s)
Adenina/análogos & derivados , Antivirales/uso terapéutico , Virus de la Hepatitis B/efectos de los fármacos , Hepatitis B Crónica/tratamiento farmacológico , Organofosfonatos/uso terapéutico , Adenina/efectos adversos , Adenina/uso terapéutico , Adulto , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Guanina/análogos & derivados , Guanina/uso terapéutico , Antígenos e de la Hepatitis B/sangre , Hepatitis B Crónica/sangre , Hepatitis B Crónica/virología , Humanos , Masculino , Cumplimiento de la Medicación , Persona de Mediana Edad , Organofosfonatos/efectos adversos , Tenofovir , Resultado del Tratamiento , Adulto Joven
5.
Aliment Pharmacol Ther ; 47(8): 1181-1200, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-29479728

RESUMEN

BACKGROUND: Hepatitis B virus (HBV) infection is common with major clinical consequences. In Asian Americans, the HBsAg carrier rate ranges from 2% to 16% which approximates the rates from their countries of origin. Similarly, HBV is the most important cause of cirrhosis, hepatocellular carcinoma (HCC) and liver related deaths in HBsAg positive Asians worldwide. AIM: To generate recommendations for the management of Asian Americans infected with HBV. METHODS: These guidelines are based on relevant data derived from medical reports on HBV from Asian countries as well as from studies in the HBsAg positive Asian Americans. The guidelines herein differ from other recommendations in the treatment of both HBeAg positive and negative chronic hepatitis B (CHB), in the approach to HCC surveillance, and in the management of HBV in pregnant women. RESULTS: Asian American patients, HBeAg positive or negative, with HBV DNA levels >2000 IU/mL (>104 copies/mL) and ALT values above normal are candidates for anti-viral therapy. HBeAg negative patients with HBV DNA >2000 IU/mL and normal ALT levels but who have either serum albumin <3.5 g/dL or platelet count <130 000 mm3 , basal core promoter (BCP) mutations, or who have first-degree relatives with HCC should be offered treatment. Patients with cirrhosis and detectable HBV DNA must receive life-long anti-viral therapy. Indications for treatment include pregnant women with high viraemia, coinfected patients, and those requiring immunosuppressive therapy. In HBsAg positive patients with risk factors, life-long surveillance for HCC with alpha-fetoprotein (AFP) testing and abdominal ultrasound examination at 6-month intervals is required. In CHB patients receiving HCC treatments, repeat imaging with contrast CT scan or MRI at 3-month intervals is strongly recommended. These guidelines have been assigned to a Class (reflecting benefit vs. risk) and a Level (assessing strength or certainty) of evidence. CONCLUSIONS: Application of the recommendations made based on a review of the relevant literature and the opinion of a panel of Asian American physicians with expertise in HBV treatment will inform physicians and improve patient outcomes.


Asunto(s)
Antivirales/uso terapéutico , Asiático , Hepatitis B Crónica/tratamiento farmacológico , Guías de Práctica Clínica como Asunto , Carcinoma Hepatocelular/tratamiento farmacológico , Consenso , Humanos , Cirrosis Hepática/tratamiento farmacológico , Neoplasias Hepáticas/tratamiento farmacológico
6.
Oncogene ; 36(22): 3178-3192, 2017 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-28092672

RESUMEN

Simultaneous hyperactivation of stress-activated protein kinase/c-Jun N-terminal protein kinase (SAPK/JNK) and mitogen-activated protein kinase kinase/extracellular signal-regulated kinase (MEK/ERK) signaling cascades has been reported in carcinogenesis. However, how they are integrated to promote oncogenesis remains unknown. By analyzing breast invasive carcinoma database (The Cancer Genome Altas), we found that the mRNA expression levels of both JNK1 and ERK2 are positively correlated with the mRNA level of EEA1, an endosome associated protein, indicating the potential JNK/ERK crosstalk at endosome. Unbiased screen of different endosome-associated Rab GTPases reveals that late endosome serves as a unique platform to integrate JNK/ERK signaling. Furthermore, we identify that BPGAP1 (a BCH domain-containing, Cdc42GAP-like Rho GTPase-activating protein) promotes MEK partner 1 (MP1)-induced ERK activation on late endosome through scaffolding MP1/MEK1 complex. This regulatory function requires phosphorylation of BPGAP1 by JNK at its C terminal tail (Ser424) to unlock its autoinhibitory conformation. Consequently, phosphorylated BPGAP1 facilitates endosomal ERK signaling transduction to the nucleus, driving cell proliferation and transformation via the ERK-Myc-CyclinA axis. BPGAP1 therefore provides a crucial spatiotemporal checkpoint where JNK and MP1/MEK1 work in concert to regulate endosomal and nuclear ERK signaling in cell proliferation control.


Asunto(s)
Proteínas Activadoras de GTPasa/metabolismo , Sistema de Señalización de MAP Quinasas , Carcinogénesis , Quinasas MAP Reguladas por Señal Extracelular/genética , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Proteínas Activadoras de GTPasa/genética , Humanos , Proteínas Quinasas JNK Activadas por Mitógenos/genética , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Unión Proteica , Transducción de Señal , Transfección
7.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 52(7): 404-409, 2017 Jul 09.
Artículo en Zh | MEDLINE | ID: mdl-29972903

RESUMEN

Objective: To investigate the effect of corticotomy-facilitated orthodontics on the treatment time and final outcome in skeletal class Ⅱ division 1 patients. Methods: Twenty adult skeletal class Ⅱ division 1 patients treated with two maxillary first premolar extractions were included and randomly divided into two groups (the corticotomy group and the control group). The treatment time was recorded and the changes of soft and hard tissue were compared by using three-dimensional measurement and analysis of cone-beam CT images before and after treatment. Results: There was no significant difference in the alignment time between two groups, while the time of maxillary space closure and the total treatment time in corticotomy group ([5.8±1.3] and [24.9±5.1] months, respectively) were shorter than that in the control group ([9.9±1.1] and [30.8±4.6] months, respectively) and the differences were significant (P<0.01). In the corticotomy group, the retraction amount of the upper central in cisal margin, apical tip, supradentale, labrale superius and the increase of nasolabial angle were greater than those in the control group (P<0.05). Conclusions: In patients with mild to moderate skeletal class Ⅱ division 1 malocclusion, corticotomy-facilitated orthodontics can not only shorten the treatment time, but is more conductive to the retraction of upper anterior teeth and improvement of the profile.


Asunto(s)
Maloclusión Clase II de Angle/cirugía , Alveolo Dental/cirugía , Adulto , Diente Premolar/cirugía , Tomografía Computarizada de Haz Cónico , Humanos , Maxilar , Tempo Operativo , Extracción Dental , Técnicas de Movimiento Dental
8.
Aliment Pharmacol Ther ; 43(1): 134-44, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26510638

RESUMEN

BACKGROUND: Entecavir (ETV) has been shown to be safe and efficacious in randomised controlled trials in highly selected patients with hepatitis B virus (HBV) infection. AIM: To determine the safety and effectiveness of ETV in 'real-world' HBV patients in the United States (US). METHODS: Treatment-naïve HBV patients ≥18 years old who received ETV for ≥12 months between 2005 and 2013 were included in a retrospective, cohort study. Rates of ALT normalisation, undetectable HBV DNA, HBeAg and HBsAg loss/seroconversion, adverse events (AE) and clinical outcomes were evaluated. RESULTS: Of 841 patients, 658 [65% male, 83% Asian; median age 47 years] met the inclusion criteria. 36% were HBeAg+ and 9.3% cirrhotic. 89% had abnormal ALT. Baseline median HBV DNA was 5.8 log 10 IU/mL. Median duration of ETV treatment was 4 years. Rates of ALT normalisation at 1, 3 and 5 years were 37.2%, 48.7% and 56.2% in HBeAg+ and 39.6%, 46.8% and 55.6% in HBeAg- patients. HBV DNA was undetectable at 1, 3 and 5 years in 34.6%, 64.7% and 84.6% in HBeAg+ patients, and 81.9%, 90.3% and 96.2% in HBeAg patients. Five-year cumulative probability of HBeAg loss and seroconversion was 46% and 33.7% and HBsAg loss was 4.6%. ETV was discontinued due to adverse events in 1.2% of patients. Hepatic decompensation occurred in 0.8%, liver cancer in 2.7% and death in 0.6%. CONCLUSION: Entecavir treatment was safe in a large cohort of US patients, but ALT normalisation and hepatitis B virus DNA suppression rates were lower than previously reported in clinical trials.


Asunto(s)
Antivirales/uso terapéutico , Guanina/análogos & derivados , Hepatitis B Crónica/tratamiento farmacológico , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Antivirales/administración & dosificación , Antivirales/efectos adversos , Femenino , Guanina/administración & dosificación , Guanina/efectos adversos , Guanina/uso terapéutico , Antígenos de Superficie de la Hepatitis B/inmunología , Antígenos e de la Hepatitis B/inmunología , Virus de la Hepatitis B/genética , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Adulto Joven
9.
J Mol Biol ; 264(4): 675-95, 1996 Dec 13.
Artículo en Inglés | MEDLINE | ID: mdl-8980678

RESUMEN

The Fis protein from Escherichia coli and Salmonella typhimurium regulates many diverse reactions including recombination, transcription, and replication and is one of the most abundant DNA binding proteins present in the cell under certain physiological conditions. As a specific regulator, Fis binds to discrete sites that are poorly related in primary sequence. Analysis of DNA scission by a collection of Fis conjugates to 1,10-phenanthroline-copper combined with comparative gel electrophoresis has shown that the structures of Fis-DNA complexes are highly variable, displaying overall DNA curvatures that range from < or = 50 degrees to > or = 90 degrees. This variability is primarily determined by differential wrapping of flanking DNA around Fis. By contrast, DNA bending within the core recognition regions appears similar among the binding sites that were analyzed. Flanking DNA contacts by Fis depend on the nucleotide sequence and are mediated by an electrostatic interaction with arginine 71 and a hydrogen bond with asparagine 73, both of which are located outside of the helix-turn-helix DNA binding motif. These contacts strongly influence the kinetics of binding. These data, combined with the crystal structure of Fis, have enabled us to generate new models for Fis-DNA complexes that emphasize the variability in DNA structures within the flanking regions.


Asunto(s)
Proteínas Portadoras/química , Proteínas de Unión al ADN/química , ADN/química , Conformación de Ácido Nucleico , Conformación Proteica , Secuencia de Bases , Sitios de Unión , Proteínas Portadoras/metabolismo , ADN/metabolismo , Proteínas de Unión al ADN/metabolismo , Dimerización , Electroforesis en Gel de Poliacrilamida , Factor Proteico para Inverción de Estimulación , Secuencias Hélice-Giro-Hélice , Enlace de Hidrógeno , Factores de Integración del Huésped , Modelos Moleculares , Oligodesoxirribonucleótidos/química , Oligodesoxirribonucleótidos/metabolismo , Fenantrolinas
10.
Protein Sci ; 8(9): 1780-8, 1999 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-10493579

RESUMEN

We have recently constructed hyperactive human deoxyribonuclease I (DNase I) variants that digest double-stranded DNA more efficiently under physiological saline conditions by introducing positively charged amino acids at eight positions that can interact favorably with the negatively charged DNA phosphates. In this study, we present data from supercoiled DNA nicking, linear DNA digestion, and hyperchromicity assays that distinguish two classes of DNase I hyperactive variants based upon their activity dependence on Ca2+. Class A variants are highly dependent upon Ca2+, having up to 300-fold lower activity in the presence of Mg2+ alone compared to that in the presence of Mg2+ and Ca2+, and include Q9R, H44K, and T205K, in addition to wild-type DNase I. In contrast, the catalytic activity of Class B variants, which comprise the E13R, T14K, N74K, S75K, and N110R hyperactive variants, is relatively Ca2+ independent. A significant proportion of this difference in Ca2+-dependent activity can be attributed to one of the two structural calcium binding sites in DNase I. Compared to wild-type, the removal of Ca2+ binding site 2 by alanine replacements at Asp99, Asp107, and Glu112 decreased activity up to 26-fold in the presence of Mg2+ and Ca2+, but had no effect in the presence of Mg2+ alone. We propose that the rate-enhancing effect of Ca2+ binding at site 2 can be replaced by favorable electrostatic interactions created by proximal positively charged amino acid substitutions such as those found in the Class B variants, thus reducing the dependence on Ca2+.


Asunto(s)
Calcio/fisiología , Desoxirribonucleasa I/metabolismo , Sitios de Unión/genética , Línea Celular , ADN/metabolismo , ADN Superhelicoidal/metabolismo , Desoxirribonucleasa I/genética , Estabilidad de Enzimas/genética , Humanos , Isoenzimas/genética , Isoenzimas/metabolismo , Mutagénesis Sitio-Dirigida , Mutación Puntual
11.
Protein Sci ; 4(11): 2279-88, 1995 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-8563624

RESUMEN

We have converted the Drosophila engrailed homeodomain into a sequence-specific nuclease by linking the protein to the chemical nuclease 1,10-phenanthroline-copper (OP-Cu). Unique cysteines were introduced at six positions into the homeodomain by site-directed mutagenesis for the covalent attachment of OP-Cu. The varied DNA-binding affinity and specificity of these mutants and the DNA cleavage pattern of their OP-Cu derivatives allowed us to assess the crystal structure of the engrailed homeodomain-DNA complex. We have also achieved site-specific double-stranded DNA scission with one of the homeodomain mutants, E28C, which has the potential of being used to identify engrailed binding sites in the genome. Because the homeodomain is so well conserved among members of the homeodomain-containing protein family, other homeodomain proteins can be converted into nucleases by attaching OP-Cu at position 28 of their homeodomains.


Asunto(s)
ADN/metabolismo , Drosophila , Proteínas de Homeodominio/química , Hormonas de Insectos/química , Fenantrolinas/química , Factores de Transcripción/química , Animales , Secuencia de Bases , Sitios de Unión , Cisteína/química , ADN/química , Proteínas de Drosophila , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Hormonas de Insectos/genética , Hormonas de Insectos/metabolismo , Modelos Moleculares , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Relación Estructura-Actividad , Factores de Transcripción/genética , Factores de Transcripción/metabolismo
12.
Protein Sci ; 7(3): 628-36, 1998 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-9541395

RESUMEN

Human deoxyribonuclease I (DNase I), an enzyme used to treat cystic fibrosis patients, has been systematically analyzed by site-directed mutagenesis of residues at the DNA binding interface. Crystal structures of bovine DNase I complexed with two different oligonucleotides have implicated the participation of over 20 amino acids in catalysis or DNA recognition. These residues have been classified into four groups based on the characterization of over 80 human DNase I variants. Mutations at any of the four catalytic amino acids His 134, His 252, Glu 78, and Asp 212 drastically reduced the hydrolytic activity of DNase I. Replacing the three putative divalent metal ion-coordinating residues Glu 39, Asp 168, or Asp 251 led to inactive variants. Amino acids Gln 9, Arg 41, Tyr 76, Arg 111, Asn 170, Tyr 175, and Tyr 211 were also critical for activity, presumably because of their close proximity to the active site, while more peripheral DNA interactions stemming from 13 other positions were of minimal significance. The relative importance of these 27 positions is consistent with evolutionary relationships among DNase I across different species, DNase I-like proteins, and bacterial sphingomyelinases, suggesting a fingerprint for a family of DNase I-like proteins. Furthermore, we found no evidence for a second active site that had been previously implicated in Mn2+-dependent DNA degradation. Finally, we correlated our mutational analysis of human DNase I to that of bovine DNase I with respect to their specific activity and dependence on divalent metal ions.


Asunto(s)
Desoxirribonucleasa I/metabolismo , Animales , Sitios de Unión , Catálisis , Cationes Bivalentes , Bovinos , Análisis Mutacional de ADN , Proteínas de Unión al ADN/química , Proteínas de Unión al ADN/metabolismo , Desoxirribonucleasa I/química , Histidina/química , Humanos , Enlace de Hidrógeno , Metales , Modelos Moleculares , Plásmidos , Proteínas Recombinantes , Especificidad de la Especie , Relación Estructura-Actividad
13.
Gene ; 215(2): 291-301, 1998 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-9714828

RESUMEN

We have cloned human and murine DNase I-like cDNAs, termed LS-DNase, which are expressed at high levels in liver and spleen tissues. LS-DNase expression is highly specific to macrophage populations within these and other tissues. Mature LS-DNase from both species is a secreted, non-glycosylated protein containing 285 residues, with a calculated molecular mass of 33 kDa and a basic isoelectric point. Human and murine LS-DNase are highly conserved and share 83% identity. Sequence analysis reveals that LS-DNase shares 46% amino acid sequence identity with DNase I. However, several residues identified as important for interaction of human DNase I with actin are not conserved in both human and murine LS-DNase. Consistent with this observation, recombinant human LS-DNase possesses a DNA hydrolytic activity which, unlike DNase I, is not inhibited by G-actin. The existence of a family of DNase I-like molecules that have tissue-specific expression patterns and the possible role of a macrophage specific DNase are discussed.


Asunto(s)
Endodesoxirribonucleasas/genética , Macrófagos/enzimología , Actinas/metabolismo , Adulto , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Línea Celular , Clonación Molecular , Cartilla de ADN , Desoxirribonucleasa I/metabolismo , Endodesoxirribonucleasas/biosíntesis , Endodesoxirribonucleasas/química , Femenino , Regulación Enzimológica de la Expresión Génica , Humanos , Riñón , Hígado/citología , Hígado/enzimología , Masculino , Ratones , Datos de Secuencia Molecular , Sondas de Oligonucleótidos , Especificidad de Órganos , Reacción en Cadena de la Polimerasa , Embarazo , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/química , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Bazo/citología , Bazo/enzimología , Transfección
14.
Zhonghua Nei Ke Za Zhi ; 31(11): 686-8, 730, 1992 Nov.
Artículo en Zh | MEDLINE | ID: mdl-1284878

RESUMEN

Viral markers were studied in 79 cases of viral hepatitis with hepatic failure. The results were shown as follows: 8 cases were positive for anti-HAV IgM (10.12%); 76 cases positive for HBsAg or anti-HBc IgM (96.20%) and 41 cases positive for anti-HCV antibodies (51.89%). Among those with anti-HCV positive, 35 cases were co-infected with HBV, 5 cases with HAV and/or HCV, only one was infected with HCV alone 2 cases were HD-Ag positive (2.52%) and one not identified (1.27%). With the reference of clinical findings, patients co-infected with HBV/HCV or anti-HBc IgM positive were more critical and usually entail higher mortality. In cases with HCV co-infections, the positive HBV replication markers seems to be reduced. Hepatic failure without HBV replicative markers had a high rate of hepatic coma as well as poor outcome.


Asunto(s)
Anticuerpos Antihepatitis/análisis , Hepatitis Viral Humana/inmunología , Sobreinfección/inmunología , Adulto , Anciano , Ensayo de Inmunoadsorción Enzimática , Femenino , Hepacivirus/inmunología , Encefalopatía Hepática/etiología , Anticuerpos contra la Hepatitis B/análisis , Anticuerpos contra la Hepatitis C , Virus de la Hepatitis Delta/inmunología , Hepatitis Viral Humana/complicaciones , Hepatitis Viral Humana/microbiología , Hepatovirus/inmunología , Humanos , Masculino , Persona de Mediana Edad , Pronóstico
16.
Peptides ; 38(1): 181-8, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22986020

RESUMEN

Several studies have documented cardiovascular effects of apelin, including enhanced inotropy and vasodilation. However, these cardiovascular effects are short lived due to the predicted short circulating half-life of the apelin peptide. To address this limitation of apelin, we pursued N-terminal PEGylation of apelin and examined the cardiovascular effects of the PEGylated apelin. A 40kDa PEG conjugated apelin-36 (PEG-apelin-36) was successfully produced with N-terminal conjugation, high purity (>98%) and minimum reduction of APJ receptor binding affinity. Using an adenylate cyclase inhibition assay, comparable in vitro bioactivity was observed between the PEG-apelin-36 and unmodified apelin-36. In vivo evaluation of the PEG-apelin-36 was performed in normal rats and rats with myocardial infarction (MI). Cardiac function was assessed via echocardiography before, during a 20 min IV infusion and up to 100 min post peptide infusion. Similar increases in cardiac ejection fraction (EF) were observed during the infusion of PEG-apelin-36 and apelin-36 in normal rats. However, animals that received PEG-apelin-36 maintained significantly increased EF over the 100 min post infusion monitoring period compared to the animals that received unmodified apelin-36. Interestingly, EF increases observed with PEG-apelin-36 and apelin-36 were greater in the MI rats. PEG-apelin-36 had a prolonged circulating life compared to apelin-36 in rats. There were no changes in aortic blood pressure when PEG-apelin-36 or apelin-36 was administered. To our knowledge this is the first report of apelin PEGylation and documentation of its cardiovascular effects.


Asunto(s)
Sistema Cardiovascular/efectos de los fármacos , Péptidos y Proteínas de Señalización Intercelular/farmacología , Polietilenglicoles/química , Administración Intravenosa , Animales , Apelina , Receptores de Apelina , Presión Arterial/efectos de los fármacos , Presión Sanguínea/efectos de los fármacos , Línea Celular , Ecocardiografía , Femenino , Semivida , Humanos , Péptidos y Proteínas de Señalización Intercelular/química , Péptidos y Proteínas de Señalización Intercelular/farmacocinética , Masculino , Infarto del Miocardio/tratamiento farmacológico , Ratas , Ratas Endogámicas Lew , Receptores Acoplados a Proteínas G/metabolismo
20.
Proc Soc Exp Biol Med ; 205(1): 29-34, 1994 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-8115348

RESUMEN

Focal glomerulosclerosis is the predominant glomerular lesion in patients with drug addiction. Since mesangial expansion has been considered a precursor of glomerulosclerosis we investigated whether the use of these drugs can cause accumulation of macromolecules into mesangium which may contribute to the expansion of mesangium. The majority of drug addicts at times take drugs in groups and may thus be exposed to a variety of drugs (cocaine, alcohol, and heroin). Therefore, we studied the effect of cocaine, alcohol, and morphine alone or in combination on the accumulation of radiolabeled human immunoglobulin-G (IgG) aggregates (AHIgG125I) into glomeruli/mesangium. Cocaine enhanced accumulation of AHIgG125I at 8 hr. Glomerular levels of AHIgG125I levels were also higher in morphine treated rats when compared with untreated animals. Alcohol did not alter the deposition of AHIgG125I. But at an earlier time (4 hr) alcohol enhanced the effect of cocaine on accumulation of IgG aggregates into the mesangium. The combined effects of morphine and cocaine, or morphine and alcohol were not different than the effect of morphine alone. The enhanced accumulation of phlogogenic macromolecules into the mesangium may not only increase the quantity of mesangial matrix but may also alter the quality of matrix. This may be playing an important role in the development of glomerular injury.


Asunto(s)
Cocaína/toxicidad , Etanol/toxicidad , Mesangio Glomerular/metabolismo , Glomeruloesclerosis Focal y Segmentaria/etiología , Inmunoglobulina G/metabolismo , Glomérulos Renales/efectos de los fármacos , Morfina/toxicidad , Alcoholismo/complicaciones , Animales , Interacciones Farmacológicas , Mesangio Glomerular/ultraestructura , Oro , Humanos , Radioisótopos de Yodo , Glomérulos Renales/inmunología , Glomérulos Renales/metabolismo , Hígado/efectos de los fármacos , Hígado/metabolismo , Pulmón/efectos de los fármacos , Pulmón/metabolismo , Masculino , Ratas , Ratas Sprague-Dawley , Bazo/efectos de los fármacos , Bazo/metabolismo , Trastornos Relacionados con Sustancias/complicaciones
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA