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Mesenchymal stromal cells (MSCs) have long been considered a potential tool for treatment of allergic inflammatory diseases, owing to their immunomodulatory characteristics. In recent decades, the medical utility of MSCs has been evaluated both in vitro and in vivo, providing a foundation for therapeutic applications. However, the existing limitations of MSC therapy indicate the necessity for novel therapies. Notably, small extracellular vesicles (sEV) derived from MSCs have emerged rapidly as candidates instead of their parental cells. The acquisition of abundant and scalable MSC-sEV is an obstacle for clinical applications. The potential application of MSC-sEV in allergic diseases has attracted increasing attention from researchers. By carrying biological microRNAs or active proteins, MSC-sEV can modulate the function of various innate and adaptive immune cells. In this review, we summarise the recent advances in the immunomodulatory properties of MSCs in allergic diseases, the cellular sources of MSC-sEV, and the methods for obtaining high-quality human MSC-sEV. In addition, we discuss the immunoregulatory capacity of MSCs and MSC-sEV for the treatment of asthma, atopic dermatitis, and allergic rhinitis, with a special emphasis on their immunoregulatory effects and the underlying mechanisms of immune cell modulation.
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Asma , Vesículas Extracelulares , Células Madre Mesenquimatosas , MicroARNs , Humanos , Vesículas Extracelulares/metabolismo , MicroARNs/metabolismo , Asma/terapia , Asma/metabolismo , InmunomodulaciónRESUMEN
BACKGROUND: Frailty is the third most common complication of diabetes after macrovascular and microvascular complications. The aim of this study was to develop a validated risk prediction model for frailty in patients with diabetes. METHODS: The research used data from the China Health and Retirement Longitudinal Study (CHARLS), a dataset representative of the Chinese population. Twenty-five indicators, including socio-demographic variables, behavioral factors, health status, and mental health parameters, were analyzed in this study. The study cohort was randomly divided into a training set and a validation set at a ratio of 70 to 30%. LASSO regression analysis was used to screen the variables for the best predictors of the model based on a 10-fold cross-validation. The logistic regression model was applied to explore the associated factors of frailty in patients with diabetes. A nomogram was constructed to develop the prediction model. Calibration curves were applied to evaluate the accuracy of the nomogram model. The area under the receiver operating characteristic curve and decision curve analysis were conducted to assess predictive performance. RESULTS: One thousand four hundred thirty-six patients with diabetes from the CHARLS database collected in 2013 (n = 793) and 2015 (n = 643) were included in the final analysis. A total of 145 (10.9%) had frailty symptoms. Multivariate logistic regression analysis showed that marital status, activities of daily living, waist circumference, cognitive function, grip strength, social activity, and depression as predictors of frailty in people with diabetes. These factors were used to construct the nomogram model, which showed good concordance and accuracy. The AUC values of the predictive model and the internal validation set were 0.912 (95%CI 0.887-0.937) and 0.881 (95% CI 0.829-0.934). Hosmer-Lemeshow test values were P = 0.824 and P = 0.608 (both > 0.05). Calibration curves showed significant agreement between the nomogram model and actual observations. ROC and DCA indicated that the nomogram had a good predictive performance. CONCLUSIONS: Comprehensive nomogram constructed in this study was a promising and convenient tool to evaluate the risk of frailty in patients with diabetes, and contributed clinicians to screening the high-risk population.
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Diabetes Mellitus , Fragilidad , Humanos , Actividades Cotidianas , Fragilidad/diagnóstico , Fragilidad/epidemiología , Estudios Longitudinales , Diabetes Mellitus/diagnóstico , Diabetes Mellitus/epidemiologíaRESUMEN
Aging has gradually accelerated in China, and achieving successful aging of older adults has become a public health concern. Intergenerational support is crucial for Chinese older adults in later life due to the culture of filial piety. However, the association between successful aging and intergenerational support remains poorly understood in China. This study aimed to examine the association between patterns of intergenerational support and successful aging of older adults in China. The present study is a secondary analysis of data obtained from the follow-up survey of the China Health and Retirement Longitudinal Study 2018. Data were analyzed using descriptive statistics and logistic regressions. Bidirectional intergenerational support was associated with successful aging in the participants. In addition, there was an association between different intergenerational financial, caring, and emotional support patterns and elements of successful aging.
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Envejecimiento , Jubilación , Humanos , Anciano , Estudios Longitudinales , Encuestas y Cuestionarios , China , Relaciones IntergeneracionalesRESUMEN
Hematopoietic stem cells (HSCs) maintain quiescence under steady state; however, they are compelled to proliferate and expand to replenish the blood system under stress. The molecular basis underlying stress hematopoiesis remains to be fully understood. In this study, we reported that IRF7 represents an important regulator of stress hematopoiesis. Interferon regulatory factor 7 (IRF7) was dispensable for normal hematopoiesis, whereas its deficiency significantly enhanced hematopoietic stem and progenitor cells (HSPCs) regeneration and improved long-term repopulation of HSCs under stress. Mechanistic studies showed that CXCR4 was identified as a downstream target of IRF7. Overexpression of CXCR4 abrogated the enhanced proliferation and regeneration of IRF7-deficient HSPCs under stress. Similar results were obtained in HSCs from human umbilical cord blood. These observations demonstrated that IRF7 plays an important role in hematopoietic regeneration under stress.
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Trasplante de Células Madre de Sangre del Cordón Umbilical/métodos , Hematopoyesis/fisiología , Factor 7 Regulador del Interferón/metabolismo , Estrés Oxidativo/fisiología , Receptores CXCR4/metabolismo , Animales , Células Cultivadas , Sangre Fetal/metabolismo , Sangre Fetal/trasplante , Humanos , Factor 7 Regulador del Interferón/antagonistas & inhibidores , Factor 7 Regulador del Interferón/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Receptores CXCR4/genéticaRESUMEN
Group 2 innate lymphoid cells (ILC2s) play an important role in the control of tissue inflammation and homeostasis. However, the role of ILC2s in patients with end-stage renal disease (ESRD) has never been illustrated. In this study, we investigated ILC2s in ESRD patients and their clinical significance. Results showed that the frequencies and absolute numbers of ILC2s, not group 1 innate lymphoid cells or innate lymphoid cell precursors, were significantly elevated in the peripheral blood of ESRD patients when compared with those from healthy donor controls. Moreover, ILC2s from ESRD patients displayed enhanced type 2 cytokine production and cell proliferation. Plasma from ESRD patients significantly increased ILC2 levels and enhanced their effector function after in vitro treatment. The expression of phosphorylation of STAT5 in ILC2s, as well as the amounts of IL-2 in plasma, were increased in ESRD patients when compared with those from healthy donors. Clinically, ESRD patients with higher ILC2 frequencies displayed lower incidence of infectious complications during a mean of 21 month follow-up study. The proportions of ILC2s were negatively correlated with the prognostic biomarkers of chronic kidney disease, including serum parathyroid hormone, creatinine, and phosphorus, whereas they were positively correlated with serum calcium. These observations indicate that ILC2s may play a protective role in ESRD.
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Inmunidad Innata , Fallo Renal Crónico/inmunología , Subgrupos Linfocitarios/inmunología , Adulto , Animales , Biomarcadores/sangre , Estudios de Casos y Controles , Proliferación Celular , Células Cultivadas , Citocinas/metabolismo , Progresión de la Enfermedad , Femenino , Estudios de Seguimiento , Voluntarios Sanos , Humanos , Fallo Renal Crónico/sangre , Fallo Renal Crónico/mortalidad , Fallo Renal Crónico/terapia , Recuento de Linfocitos , Subgrupos Linfocitarios/metabolismo , Masculino , Persona de Mediana Edad , Cultivo Primario de Células , Pronóstico , Diálisis Renal/estadística & datos numéricosRESUMEN
Objective To investigate the effects of self-made carriers on the cryopreservation of ovarian tissue of sheep. Methods Thirty-two ovaries were randomly assigned to fresh group,programmed freezing group,self-made carrier I vitrification group,and self-made carrier â ¡ vitrification group.The morphology,proliferation,apoptosis,and estrogen level of the ovarian tissue in each group were observed. Results After cryopreservation,the morphology normal rate of the primordial follicles in programmed freezing group,self-made carrier I vitrification group,and self-made carrier â ¡ vitrification group were 74.2%,72.8%,and 72.3%,respectively,lower than that(83.7%)in the fresh group(χ2=13.079,P=0.004).The percentage of normal primary follicles in programmed freezing group was lower than that in the fresh group(χ2=12.486,P=0.000).The percentage of normal primary follicles showed no significant difference between vitrification groups and fresh group(P=1.000,P=0.972).There was no significant difference in estrogen level or the positive expression rate of PCNA among the 4 groups(F=0.363,P=0.780;χ2=0.359,P=0.949).The number of apoptotic cells in cryopreservation groups was significantly higher than that in the fresh group(F=37.584,P=0.000),and it was significantly higher in the programmed freezing group than in the two vitrification groups(F=18.992,P=0.000). Conclusion Compared with slow programmed freezing,the vitrification with self-made carriers could well preserve the activity of cells in large sheep ovarian tissue blocks.
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Criopreservación , Vitrificación , Animales , Femenino , Congelación , Folículo Ovárico , Ovario , OvinosRESUMEN
WHAT IS KNOWN AND OBJECTIVE: Ceritinib is a new, oral, potent and selective second-generation anaplastic lymphoma kinase (ALK) inhibitor approved by the Food and Drug Administration of the United States in April 2014. It is active in crizotinib-resistant patients, especially in patients with non-small cell lung cancer (NSCLC) and brain metastasis. The aim of this study was to analyse the effects and side effects of ceritinib in ALK-rearranged NSCLC. METHODS: We searched articles published from January 1980 to March 2019 in PubMed, EMBASE, Cochrane Library and Web of Science. The pooled estimate and 95% CI were calculated with DerSimonian-Laird method and the random effect model. RESULTS AND DISCUSSION: From 15 articles, 2,598 patients were included in the meta-analysis. Eleven studies reported the ORR, and the DCR was presented in 10 studies. The ORR and DCR of ceritinib were 0.48 (95% CI, 0.39-0.57) and 0.76 (95% CI, 0.69-0.82), respectively. The PFS and OS were presented in nine and three eligible studies, respectively. The PFS and OS of ceritinib were 7.26 months (95% CI, 5.10-9.43) and 18.73 months (95% CI; 14.59-22.87). These results suggested that ceritinib can effectively treat patients with ALK-rearranged NSCLC. Diarrhoea, nausea and vomiting were the three most common AEs and occurred in 69% (95% CI 51.7-87.1%), 66% (95% CI 47.0-85.8%) and 51% (95% CI 35.9-66.8%) of patients, respectively. Considering serious gastrointestinal AEs, antiemetic and antidiarrhoeal drugs should be considered to improve a patient's tolerance to ceritinib. WHAT IS NEW AND CONCLUSION: Ceritinib is effective in the treatment of patients with ALK-rearranged NSCLC with crizotinib resistance. The DCR was up to 76%, and PFS was extended to 7.6 months. The AEs were acceptable.
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Quinasa de Linfoma Anaplásico/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Neoplasias Pulmonares/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/uso terapéutico , Pirimidinas/efectos adversos , Pirimidinas/uso terapéutico , Sulfonas/efectos adversos , Sulfonas/uso terapéutico , Neoplasias Encefálicas/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Humanos , Neoplasias Pulmonares/metabolismoRESUMEN
Two psychrotolerant facultative anaerobes, strains B7-2T and B5T, were isolated from the Zoige Wetland on the Qinghai-Tibetan Plateau. The 16S rRNA gene sequences of strains B7-2T and B5T shared high similarity (>99â%) with those of the type strains of the genus Trichococcus, while their digital DNA-DNA hybridization values with each other (49â%) and with the reference type strains (48-23â%) were lower than 70â%, which suggest that they represent two novel species of the genus Trichococcus. Cells of strains B7-2T and B5T were immotile cocci, grew in the temperature range of 4-37 °C (optimum 25 °C) and were alkaliphilic with optimum growth at pH 9.0. The major components of the cellular fatty acids were C16â:â0, anteiso-C17â:â0 and C18â:â0 for strain B7-2T, and C16â:â0, anteiso-C17â:â0, C18â:â1ω9c and C18â:â0 for strain B5T. The genomic DNA G+C contents were 46.0 and 46.7 mol% for strains B7-2T and B5T, respectively. Based on physiological and genomic characteristics, it is suggested that strains B7-2T and B5T represent two novel species within the genus Trichococcus, for which the names Trichococcus paludicola sp. nov. and Trichococcus alkaliphilus sp. nov. are proposed. The type strains are B7-2T (=DSM 104691T=KCTC 33886T) and B5T (=DSM 104692T=KCTC 33885T), respectively.
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Carnobacteriaceae/clasificación , Filogenia , Humedales , Técnicas de Tipificación Bacteriana , Composición de Base , Carnobacteriaceae/genética , Carnobacteriaceae/aislamiento & purificación , China , ADN Bacteriano/genética , Ácidos Grasos/química , Hibridación de Ácido Nucleico , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADNRESUMEN
In the title compound, [Ni(C(6)H(12)N(4)O(3))(2)](NO(3))(2)·4H(2)O, the Ni(II) cation is located on an inversion center and is N,O,O'-chelated by two nitrilo-tris-(acetamide) mol-ecules in a distorted octa-hedral geometry. The complex cations, nitrate anions and lattice water mol-ecules are connected by O-Hâ¯O and N-Hâ¯O hydrogen bonds, forming a three-dimensional supra-molecular structure.
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OBJECTIVE: To investigates factors affecting the positive rate of blocking antibody treated by paternal lymphocyte immunotherapy in patients with recurrent spontaneous abortion (RSA). METHODS: From January 2008 to August 2012, 326 RSA cases undergoing treatment in Infertility Center of Qilu Hospital were studied retrospectively. Those patients were divided into 2 groups randomly: 260 cases in intradermal injection group were administered via bilateral forearm intradermal injections for immunotherapy once 21 days, then the blocking antibody was determined after 2 (23 cases) , 3(73 cases), 4 (74 cases) , 5(90 cases) times respectively, while in subcutaneous injection group, the 66 cases were administered via subcutaneous injection once 21 days, the blocking antibody measured after 3 times; In both cases, the blocking antibody was all determined 2 weeks later. The positive rate of blocking antibodies and the rate of successful pregnancy was recorded, and then followed up after the blocking antibody turning positive. RESULTS: (1) Positive rate of blocking antibodies:the positive rate of blocking antibodies were 17% (4/23) , 58% (42/73), 72% (53/74) and 84% (76/90) in the 2, 3, 4, and 5 times of intradermal injection group, respectively (P < 0.05). In subcutaneous injection group, the positive rate of blocking antibodies was 38 % (25/66), which was significantly lower than that in group intradermal injection receiving 3 times immunotherapy (P < 0.05). (2) The rate of pregnancy:the 176 patients out of 200 patients were pregnant when antibody was positive after immunotherapy, with 71.6% (126/176) of patients gained successful pregnancy(the length of pregnancy more than 5 months). CONCLUSIONS: The route and frequency of administration of immunotherapy could influence the positive rate of blocking antibody. The rate of successful pregnancy will be increased after blocking antibody turning positive.
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Aborto Habitual/inmunología , Anticuerpos Bloqueadores/sangre , Padre , Inmunoterapia/métodos , Linfocitos/inmunología , Aborto Habitual/terapia , Adulto , Anticuerpos Bloqueadores/metabolismo , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Inyecciones Subcutáneas , Activación de Linfocitos/inmunología , Masculino , Persona de Mediana Edad , Embarazo , Índice de Embarazo , Resultado del Tratamiento , Adulto JovenRESUMEN
Noise-induced hearing loss (NIHL) is one of the most prevalent acquired sensorineural hearing loss etiologies and is characterized by the loss of cochlear hair cells, synapses, and nerve terminals. Currently, there are no agents available for the treatment of NIHL because drug delivery to the inner ear is greatly limited by the blood-labyrinth barrier. In this study, we used mesenchymal stem cell-derived small extracellular vesicles (MSC-sEVs) as nanoscale vehicles to deliver brain-derived neurotrophic factor (BDNF) and evaluated their protective effects in a mouse model of NIHL. Following intravenous administration, BDNF-loaded sEVs (BDNF-sEVs) efficiently increased the expression of BDNF protein in the cochlea. Systemic application of sEVs and BDNF-sEVs significantly attenuated noise-induced cochlear hair cell loss and NIHL in CBA/J mice. BDNF-sEVs also alleviated noise-induced loss of inner hair cell ribbon synapses and cochlear nerve terminals. In cochlear explants, sEVs and BDNF-sEVs effectively protected hair cells against H2O2-induced cell loss. Additionally, BDNF-sEVs remarkably ameliorated H2O2-induced oxidative stress, cell apoptosis, and cochlear nerve terminal degeneration. Transcriptomic analysis revealed that many mRNAs and miRNAs were involved in the protective actions of BDNF-sEVs against oxidative stress. Collectively, our findings reveal a novel therapeutic strategy of MSC-sEVs-mediated BDNF delivery for the treatment of NIHL.
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Vesículas Extracelulares , Pérdida Auditiva Provocada por Ruido , Animales , Ratones , Factor Neurotrófico Derivado del Encéfalo , Cóclea/metabolismo , Vesículas Extracelulares/metabolismo , Pérdida Auditiva Provocada por Ruido/tratamiento farmacológico , Pérdida Auditiva Provocada por Ruido/prevención & control , Peróxido de Hidrógeno/metabolismo , Ratones Endogámicos CBARESUMEN
BACKGROUNDS: Allergic airway inflammation is prevalent worldwide and imposes a considerable burden on both society and affected individuals. This study aimed to investigate the therapeutic advantages of mesenchymal stem cells (MSCs) overexpressed interleukin-10 (IL-10) for the treatment of allergic airway inflammation, as both IL-10 and MSCs possess immunosuppressive properties. METHODS: Induced pluripotent stem cell (iPSC)-derived MSCs were engineered to overexpress IL-10 via lentiviral transfection (designated as IL-10-MSCs). MSCs and IL-10-MSCs were administered intravenously to mice with allergic inflammation induced by ovalbumin (OVA), and the features of allergic inflammation including inflammatory cell infiltration, Th cells in the lungs, and T helper 2 cell (Th2) cytokine levels in bronchoalveolar lavage fluid (BALF) were examined. MSCs and IL-10-MSCs were co-cultured with CD4+ T cells from patients with allergic rhinitis (AR), and the levels of Th2 cells and corresponding type 2 cytokines were studied. RNA-sequence was performed to further investigate the potential effects of MSCs and IL-10-MSCs on CD4+ T cells. RESULTS: Stable IL-10-MSCs were established and characterised by high IL-10 expression. IL-10-MSCs significantly reduced inflammatory cell infiltration and epithelial goblet cell numbers in the lung tissues of mice with allergic airway inflammation. Inflammatory cell and cytokine levels in BALF also decreased after the administration of IL-10-MSCs. Moreover, IL-10-MSCs showed a stronger capacity to inhibit the levels of Th2 after co-cultured with CD4+ T cells from patients with AR. Furthermore, we elucidated lower levels of IL-5 and IL-13 in IL-10-MSCs treated CD4+ T cells, and blockade of IL-10 significantly reversed the inhibitory effects of IL-10-MSCs. We also reported the mRNA profiles of CD4+ T cells treated with IL-10-MSCs and MSCs, in which IL-10 played an important role. CONCLUSION: IL-10-MSCs showed positive effects in the treatment of allergic airway inflammation, providing solid support for the use of genetically engineered MSCs as a potential novel therapy for allergic airway inflammation.
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Células Madre Mesenquimatosas , Rinitis Alérgica , Animales , Humanos , Ratones , Líquido del Lavado Bronquioalveolar , Citocinas/metabolismo , Modelos Animales de Enfermedad , Inflamación/terapia , Inflamación/metabolismo , Interleucina-10/genética , Interleucina-10/metabolismo , Pulmón , Células Madre Mesenquimatosas/metabolismo , Ratones Endogámicos BALB C , OvalbúminaRESUMEN
The title compound, [Ni(4)(C(6)H(5)N(3)O)(2)(C(6)H(6)N(3)O)(2)(C(5)H(5)N)(4)](NO(3))(2), is a tetra-nuclear nickel complex containing a single-decker cation, located on an inversion center. The two unique Ni(II) cations are N,N',N'',O-chelated by carbox-imid-amid-ate(2-) and carboximidamidate(1-) anions, forming a distorted four-coordinate planar structure, while the other two Ni(II) atoms are N,N',O,O'-chelated by the same bridging ligands and two pyridine mol-ecules, affording six-coordinated metals in an octa-hedral geometry. The cation is isostructural with the complex crystallized with perchlorate counter-ions in place of nitrate.
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OBJECTIVE: To study the expression of gene associated with retinoid-interferon-induced mortality-19(GRIM-19) in preimplantation embryo of mice and explore its role in embryonic development. METHODS: The protein and mRNA expressions of GRIM-19 in 2-cell, 4-cell, 8-cell, morula, and blastocyst phases of mice preimplantation embryo were detected by Western blot analysis and Real-time polymerase chain reaction (PCR). RESULTS: GRIM-19 was continuously expressed in every stage of preimplantation embryo of mice. Western blot analysis and Real-time PCR demonstrated a gradual increase of GRIM-19 expression from 2-cell, which reached a peak in 8-cell phase and then decreased progressively. CONCLUSIONS: The expression of GRIM-19 in mouse preimplantation embryos changes as at different developmental phases. GRIM-19 may play an important role during embryonic development.
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Blastocisto/metabolismo , Interferones/farmacología , NADH NADPH Oxidorreductasas/metabolismo , Tretinoina/farmacología , Animales , Blastocisto/efectos de los fármacos , Femenino , Ratones , NADH NADPH Oxidorreductasas/genética , Embarazo , ARN Mensajero/genéticaRESUMEN
In the title dinuclear compound, [Zn(2)(C(6)H(6)N(3)O)(2)(C(6)H(7)N(3)O)(2)](NO(3))(2), the Zn(II) cation is N,N'-chelated by one pyridine-2-carboxamide oximate anion and one pyridine-2-carboxamide oxime mol-ecule, and is further bridged by an oxime O atom from the adjacent pyridine-2-carboxamide oximate anion, forming a distorted trigonal bipyramidal coordination. Two pyridine-2-carboxamide oximate anions bridge two Zn(II) cations to form the centrosymmetric dinuclear mol-ecule. Extensive O-Hâ¯O, N-Hâ¯O and O-Hâ¯N hydrogen bonds are present in the crystal structure.
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OBJECTIVE: To screen the antithrombotic active fraction of Naodesheng. METHODS: The collagen and adrenaline-induced thrombosis by tail intravenous injection in mice was used. Based on orthogonal design, the support vector machine model was established for pharmacodynamics prediction of TCM prescriptions. RESULTS: The model established in this study could predict the drug actions of different combinations. CONCLUSION: The pharmacodynamic actions of several formulas are superior to that of the original formula and CD has the best effect.
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Medicamentos Herbarios Chinos/química , Medicamentos Herbarios Chinos/farmacología , Fibrinolíticos/química , Fibrinolíticos/farmacología , Máquina de Vectores de Soporte , Trombosis/tratamiento farmacológico , Algoritmos , Animales , Fraccionamiento Químico , Simulación por Computador , Combinación de Medicamentos , Descubrimiento de Drogas/métodos , Medicamentos Herbarios Chinos/aislamiento & purificación , Femenino , Fibrinolíticos/aislamiento & purificación , Masculino , Ratones , Ratones Endogámicos , Modelos Estadísticos , Plantas Medicinales/química , Distribución Aleatoria , Relación Estructura-Actividad , Trombosis/inducido químicamenteRESUMEN
A new alkaloid (1), together with five known compounds (2-6), has been isolated from the stem of Sparganium stoloniferum Buch.-Ham. The structure of the new compound was elucidated as 3-isobutyl-tetrahydro-imidazo[1,2-a]pyridine-2,5-dione on the basis of physical and chemical evidence and spectral analysis. Compound 6 was obtained for the first time from the Sparganium genus.
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Alcaloides/aislamiento & purificación , Medicamentos Herbarios Chinos/aislamiento & purificación , Magnoliopsida/química , Piridonas/aislamiento & purificación , Alcaloides/química , Medicamentos Herbarios Chinos/química , Estructura Molecular , Tallos de la Planta/química , Piridonas/químicaRESUMEN
OBJECTIVE: To explore the mechanism for adefovir dipivoxil (ADV) resistance occurred in chronic hepatitis B patients of a series of phase III clinical trails. METHODS: 30 resistant HBV strains were selected out from 177 cases of ADV treated chronic hepatitis B patients. HBV polymerase RT region were amplified by nested PCR and analyzed with the standard nucleotide sequence of HBV strains deposited in GeneBank. RESULTS: 21 out of 30 HBV strains were primary resistant strains, among them 5 HBV strains (23.8%, 5/21) had the polymorphism site of rtN118H. While the other 9 HBV strains showed secondary resistance, variations in conservative region C (rtM207V) and other non-conservative regions were found. The classic mutation sites such as rtN236T and rtA181V/T were not found. CONCLUSIONS: Polymorphism site of rtN118H might be responsible for HBV primary resistance to ADV therapy. rtM207V variation in HBV RT C domain and other variation sites might play a role in HBV secondary resistance to ADV treatment, and natural resistant quasispecies may be the basis for the ADV quick resistance. These conclusions await further confirmation by phenotype test.