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1.
Zhonghua Gan Zang Bing Za Zhi ; 30(11): 1280-1284, 2022 Nov 20.
Artigo em Chinês | MEDLINE | ID: mdl-36891712

RESUMO

Portal vein thrombosis (PVT) is one of the common complications of cirrhosis, which induces or aggravates ascites and upper gastrointestinal bleeding and even impacts the difficulty of liver transplantation by raising portal pressure, hence deteriorating the prognosis of patients. With the revelation of PVT-related research findings in recent years, the recognition of its mechanism and clinical risks has deepened. This article reviews the latest progress in PVT formation mechanisms and treatment strategies to improve clinicians' recognition of the pathogenesis and aid in formulating reasonable prevention and treatment.


Assuntos
Transplante de Fígado , Trombose Venosa , Humanos , Veia Porta/patologia , Cirrose Hepática/complicações , Cirrose Hepática/patologia , Trombose Venosa/complicações , Transplante de Fígado/efeitos adversos , Hemorragia Gastrointestinal/patologia
2.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 56(12): 1277-1281, 2021 Dec 09.
Artigo em Chinês | MEDLINE | ID: mdl-34915665

RESUMO

With the increasing integration of artificial intelligence (AI) with other fields, machine learning, one of the major methods in AI, has been extensively applied in dentistry in the stage of diagnosis, therapy and prognosis evaluation. Nowadays, numerous studies have reported the applications of machine learning in orthodontics in two major aspects, including image identification and clinical decision support system. Herein, we reviewed the application progress of machine learning in orthodontics in order to provide new insight for the future precision medicine.


Assuntos
Ortodontia , Inteligência Artificial , Aprendizado de Máquina
3.
Zhonghua Zhong Liu Za Zhi ; 43(10): 1094-1099, 2021 Oct 23.
Artigo em Chinês | MEDLINE | ID: mdl-34695901

RESUMO

Objective: To evaluate the performance of high risk human papilloma virus (HR-HPV) E6/E7 mRNA in triaging women with atypical squamous cells of undetermined signification (ASCUS). Methods: The ASCUS cohort determined by liquid-based cytology test in the cervical cancer screening queue in Luoshan County, Xinyang City, Henan Province 2017 were selected. The population underwent colposcopy biopsy and pathological tests, combined with HPV16 or 18 (HPV16/18), HR-HPV DNA and HPV E6/E7 mRNA test. By using the pathological result as the gold standard, the sensitivity, specificity, positive predictor (PPV), negative prediction (NPV), referral rate and 95% confident interval (CI) of HPV E6/E7 mRNA, HR-HPV DNA, HPV16/18 were calculated, respectively. Results: The average age of 312 ASCUS women was 52.6±7.3 years old. Among the 290 women diagnosed as normal by pathology, 64 (22.1%) were HPV E6/E7 mRNA positive, 86 (29.7%) were HR-HPV DNA positive, and 19 (6.6%) were HPV16/18 positive. All of the cervical intraepithelial neoplasia (CIN) cases determined by pathology were both HPV E6/E7 mRNA and HR-HPV DNA positive. The sensitivity, specificity, PPV, NPV and referral rate of HPV E6/E7 mRNA for predicting CIN2+ lesion in women with ASCUS were 100.0% (95%CI: 72.3, 100.0), 77.8% (95%CI: 72.8, 82.1), 13.0% (95%CI: 7.2, 22.3), 100.0% (95%CI: 98.4, 100.0) and 24.7%. Compared with HPV E6/E7 mRNA, the sensitivity of HR-HPV DNA was similar with HPV E6/E7 mRNA, but with a lower specificity [70.2% (95%CI: 64.8, 75.1), P<0.05], a higher referral rate (32.1%, P<0.05); while HPV 16/18 had a high specificity (93.4%, 95%CI: 90.0, 95.7) and a low sensitivity (30.0%, 95%CI: 10.8, 60.3). Based on the age stratification by age 45, the sensitivity of HPV E6/E7 mRNA in both age groups was 100.0%. The specificity of HPV E6/E7 mRNA in group of ≥45 years was a little higher than that in group of <45 years [79.0% (95%CI: 73.7, 83.5) versus 68.3% (95% CI: 53.0, 80.4)], but the difference was not statistically significant (P>0.05). Conclusions: The ASCUS woman triaging effect of HPV E6/E7 mRNA detection is better than those of HR-HPV and HPV16/18 under certain conditions. The application of HPV E6/E7 mRNA detection to triage ASCUS population can avoid unnecessary colposcopy referral and reduce the missed diagnosis of cervical lesions.


Assuntos
Células Escamosas Atípicas do Colo do Útero , Infecções por Papillomavirus , Neoplasias do Colo do Útero , Detecção Precoce de Câncer , Feminino , Papillomavirus Humano 16/genética , Papillomavirus Humano 18/genética , Humanos , Pessoa de Meia-Idade , Papillomaviridae/genética , Infecções por Papillomavirus/diagnóstico , RNA Mensageiro/genética , Sensibilidade e Especificidade , Triagem , Neoplasias do Colo do Útero/diagnóstico
4.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 55(10): 794-798, 2020 Oct 09.
Artigo em Chinês | MEDLINE | ID: mdl-33045794

RESUMO

Temporomandibular disorders (TMD) is one of the most common diseases in the orofacial region. The occurrence, development and outcome of TMD are affected by many factors. Among various risk factors, the psychological factors, especially anxiety, depression and somatic symptoms, are getting more and more attention in the etiology, diagnosis and treatment of TMD. Psychological factors are associated with the occurrence of TMD, and the accurate diagnostic criteria is conducive to the assessment of the patient's psychological state. If necessary, an appropriate psychological treatment according to a patient's psychological status can effectively improve the effect of clinical treatment. This article, based on domestic and international literatures, reviews the research progress of the correlation between the psychological factors and the etiology, diagnosis and treatment of TMD, in order to provide new ideas for clinicians to diagnose and treat TMD.


Assuntos
Transtornos da Articulação Temporomandibular , Ansiedade , Humanos , Fatores de Risco , Transtornos da Articulação Temporomandibular/diagnóstico , Transtornos da Articulação Temporomandibular/terapia
5.
Zhonghua Yu Fang Yi Xue Za Zhi ; 54(2): 192-197, 2020 Feb 06.
Artigo em Chinês | MEDLINE | ID: mdl-32074709

RESUMO

Objective: This study aimed to evaluate the clinical performance of p16/Ki-67 dual staining for triage high risk HPV (HR-HPV) infected women. Method: Target objects were women who infected HR-HPV and received colposcopy examination between April and December of 2016 at the Second Affiliated Hospital of Zhengzhou University. Gynecologists collected the cervical exfoliated cells from eligible women for p16/Ki-67 dual staining, LBC testing and HPV DNA testing. Histology diagnosis were used as gold standard. Sensitivities, specificities, positive predictive values (PPVs), negative predictive values (NPVs) of p16/Ki-67 dual staining, LBC testing and HPV16/18 testing for triage of HR-HPV positive population were calculated and compared. Results: A total of 295 HR-HPV infected women were selected, and the mean age was (44.29±11.48) years old. Positive rates of p16/Ki-67 dual staining, HPV16/18 testing and LBC testing were 70.17% (207), 56.95% (168) and 85.76% (253), respectively. When CIN2+as the endpoint, among the three triage methods, sensitivity of p16/Ki-67 dual staining was 90.00% (95%CI: 85.06%-93.43%), higher than the value of HPV 16/18 testing, but lower than the value of LBC testing. Specificity, PPV and NPV of p16/Ki-67 dual staining were the highest [71.58% (95%CI: 61.81%-79.67%), 86.96% (95%CI:81.69%-90.88%) and 77.27% (95%CI: 67.49%-84.78%)]. When detection for CIN3+, sensitivity of p16/Ki-67 dual staining was 92.90% (95%CI: 87.74%-95.99%), lower than the value of LBC testing, but higher than the value of HPV16/18 testing. Specificity of p16/Ki-67 dual staining was 55.00% (95%CI: 46.74%-63.00%), lower than the value of HPV16/18 testing, but higher than the value of LBC testing. PPV of p16/Ki-67 dual staining was 69.57% (95%CI: 62.99%-75.43%), lower than the value of HPV 16/18 testing, but higher than the value of LBC testing. NPV of p16/Ki-67 dual staining was 87.50% (95%CI: 78.99%-92.87%), higher than value of HPV 16/18 testing, but lower than the value of LBC testing. Conclusion: p16/Ki-67 dual staining has better clinical effects than HPV 16/18 testing and LBC testing for triage women with HR-HPV infection.


Assuntos
Infecções por Papillomavirus/diagnóstico , Coloração e Rotulagem , Triagem/métodos , Adulto , Feminino , Pesquisa sobre Serviços de Saúde , Papillomavirus Humano 16/isolamento & purificação , Papillomavirus Humano 18/isolamento & purificação , Humanos , Antígeno Ki-67/isolamento & purificação , Pessoa de Meia-Idade , Medição de Risco , Sensibilidade e Especificidade
6.
Zhonghua Zhong Liu Za Zhi ; 40(6): 475-480, 2018 Jun 23.
Artigo em Chinês | MEDLINE | ID: mdl-29936777

RESUMO

Objective: To explore the relationship between high risk HPV (HR-HPV) DNA load and cervical lesions in HR-HPV single/ multiple infections. Methods: Two thousand six hundred and forty-six women from Shanxi, Henan and Xinjiang were recruited into a cervical cancer screening program. Cervical exfoliated cell specimens collected from all of the participants were detected by hybrid capture Ⅱ (HC2), cytological diagnosis was performed according to the Bethesda System, and pathological diagnosis was interpreted using cervical intraepithelial neoplasia (CIN) terminology.Totally 571 cervical specimens were selected and retested to ascertain the HPV types and single/ multiple infections by liner array, a PCR-based method. Semi-quantitative result of HR-HPV DNA load (pg/ml) was estimated by HR HC2.According to the taxonomy of "International Human Papillomavirus Reference Center" , 13 HR-HPVs, including HPV16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59 and 68, which could be detected by HR HC2 were divided into 4 subgroups. Results: The positive rate of HR-HPV in normal cervix (436 cases), CIN1 (88 cases), CIN2+ (47 cases) group were 29.82%, 85.23% and 100%, respectively. The overall prevalence and median viral load increased coordinating with the pathological degree of cervical lesions (P<0.001). The positive rate and viral load of single infection with HR-HPV belongs to α9 species increased coordinating with the pathological degree of cervical lesions (P<0.05). The viral load of single infection with HR-HPV belongs to α7 species in CIN1 group was higher than those of normal group and CIN2+ group, but without statistical significance (P=0.130). The viral load of multiple infections in CIN1 group was 559.13 pg/ml, significantly higher than 37.73 pg/ml of normal histology (P=0.025), but without significant difference of 332.91 pg/ml of CIN2+ group (P=0.790). The median viral load of HPV single infection in CIN1 group was 167.93 pg/ml, significantly lower than 559.73 pg/ml of multiple infections (P=0.044). The incidence of co-infection with HR-HPVs belong to α9 species was 80.56%, dominated in all patterns of multiple infections and their median viral load increased coordinating with the pathological degree of cervical lesions, but without significant difference (P>0.05). The incidence of co-infection with HR-HPVs belong to α7 species was 66.67%, their median viral load in CIN1 group was higher than that of CIN2+ group, but without statistical significance (P>0.05). Conclusions: Viral loads of single/ multiple infections with HR-HPVs belong to different species show different tendencies coordinating with the pathological degree of cervical lesions. Women with high grade of cervical lesion were dominantly infected with high viral load of HR-HPVs belong to α9 species, and the viral load of multiple infections is higher than that of single infection in low grade of cervical lesion.


Assuntos
DNA Viral/análise , Papillomaviridae/isolamento & purificação , Displasia do Colo do Útero/virologia , Carga Viral , Coinfecção/epidemiologia , Coinfecção/virologia , Detecção Precoce de Câncer , Feminino , Papillomavirus Humano 16 , Humanos , Incidência , Programas de Rastreamento , Pessoa de Meia-Idade , Papillomaviridae/classificação , Infecções por Papillomavirus/diagnóstico , Reação em Cadeia da Polimerase , Prevalência , Neoplasias do Colo do Útero , Carga Viral/genética , Displasia do Colo do Útero/diagnóstico , Displasia do Colo do Útero/patologia
7.
Zhonghua Zhong Liu Za Zhi ; 40(4): 313-318, 2018 Apr 23.
Artigo em Chinês | MEDLINE | ID: mdl-29730922

RESUMO

Objective: To evaluate the feasibility and effectiveness of isothermal human papillomavirus (HPV) DNA amplification test as a primary screening test in the early detection of cervical cancer. Methods: From June to August 2016, 2, 774 women aged 30-64 years old from Inner Mongolia were recruited for cervical cancer screening. HPV DNA was detected by Isomega and cobas4800. INNO-LiPA HPV Genotyping Extra was served as a reference method for the cases whose results were inconsistent by using these two methods. Histological diagnosis was considered as a gold standard to estimate the effectiveness and accuracy of Isomega and cobas4800 for detecting CIN2 or greater. Results: The concordance of Isomega and cobas4800 was 94.84% (Kappa=0.82) for high risk HPV (HR-HPV), 99.68% (Kappa=0.95) for HPV16, 99.78% (Kappa=0.91) for HPV18 and 94.34% (Kappa=0.76) for other HR-HPV types. The concordances of Isomega and the reference were 99.71% (Kappa=0.96), 99.86% (Kappa=0.94) and 96.76% (Kappa=0.87) for HPV16, 18 and other HR-HPV, respectively, while the concordances of cobas4800 and the reference were 99.82% (Kappa=0.97), 99.86% (Kappa=0.94) and 97.51% (Kappa=0.90), respectively. The sensitivity and specificity of Isomega for detecting CIN2+ (including CIN2, CIN3 and squamous cell carcinoma) were 87.76% and 82.94%, respectively, while those of cobas4800 were 89.80% and 85.06%, respectively. Conclusions: The concordances of Isomega and cobas4800 is confident. These two methods can accurately detect the HPV16 and 18 genotyping, and have good sensitivity and specificity for clinical diagnosis and population screening of cervical cancer.


Assuntos
DNA Viral/análise , Testes de DNA para Papilomavírus Humano/métodos , Papillomavirus Humano 16/genética , Técnicas de Amplificação de Ácido Nucleico/métodos , Neoplasias do Colo do Útero/diagnóstico , Adulto , Carcinoma de Células Escamosas/diagnóstico , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/virologia , China , Detecção Precoce de Câncer/métodos , Estudos de Viabilidade , Feminino , Humanos , Pessoa de Meia-Idade , Infecções por Papillomavirus/diagnóstico , Gravidez , Sensibilidade e Especificidade , Neoplasias do Colo do Útero/genética , Neoplasias do Colo do Útero/virologia , Displasia do Colo do Útero/diagnóstico , Displasia do Colo do Útero/genética , Displasia do Colo do Útero/virologia
8.
Zhonghua Bing Li Xue Za Zhi ; 47(4): 269-273, 2018 Apr 08.
Artigo em Chinês | MEDLINE | ID: mdl-29690666

RESUMO

Objective: To investigate the human papillomavirus (HPV) positive rate and its usefulness in predicting CIN2+ in women with atypical squamous cells of undetermined significance (ASC-US) cervical cytology. Methods: A pooled analysis was conducted using published data of hospital classification, HPV positive rate and histopathologic diagnosis in ASC-US population during 2005 to 2017 from 104 studies which enrolled 28 923 ASC-US samples. Results: The overall HPV positive rate was 52.09% (range from 12.06% to 88.68%). The HPV positive rate in 79 tertiary hospitals of 21 244 cases was 52.46%, slightly higher than the 50.87% in 22 second-class hospitals of 6 925 cases. There was no significant difference between specialized hospitals and general hospitals. In addition, the positive rate of HC2 conducted in 66 hospitals with 19 791 cases was 53.13%, which was slightly higher than 51.10% of reverse hybridization from 24 hospitals with 6 338 cases. In 73 studies of 18 163 cases with histological diagnosis, the sensitivity of HPV for detecting CIN2+ was 90.16% (95%CI: 88.91% to 91.28%), specificity was 53.08% (95%CI: 53.02% to 54.57%), positive predictive value was 23.24% and negative predictive value was 97.24%. Conclusion: HPV detection is clinically validated for ASC-US triage, but there is a wide variation of HPV positive rate in population of cervical cytological diagnosis as ASC-US in China, suggesting different diagnostic level between regions and hospitals and further improvement is needed.


Assuntos
Células Escamosas Atípicas do Colo do Útero/virologia , Papillomaviridae/isolamento & purificação , Infecções por Papillomavirus/virologia , Displasia do Colo do Útero/virologia , China , Feminino , Humanos , Sensibilidade e Especificidade , Triagem , Esfregaço Vaginal
9.
Zhonghua Zhong Liu Za Zhi ; 38(4): 241-5, 2016 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-27087368

RESUMO

Human papillomavirus (HPV) infection is the necessary cause of cervical cancer. There is a close relationship between the amount of DNA, mRNA and protein expression in the natural history of virus and the cervical lesion. This article is aimed to elaborate the natural history and genital tract distribution of high risk HPV, and also evaluate the HPV based cervical cancer screening technology from the perspective of the natural history of HPV, which is meaningful for screening and clinical practice in devising and utilizing different detection technology.


Assuntos
Detecção Precoce de Câncer/métodos , Papillomaviridae/isolamento & purificação , Infecções por Papillomavirus/diagnóstico , Neoplasias do Colo do Útero/virologia , DNA Viral/análise , Feminino , Humanos , Papillomaviridae/genética , RNA Mensageiro/análise , RNA Viral/análise , Neoplasias do Colo do Útero/diagnóstico
10.
Zhonghua Zhong Liu Za Zhi ; 38(4): 277-82, 2016 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-27087374

RESUMO

OBJECTIVE: To investigate the distribution of human papillomavirus (HPV) in the diseased areas cut from HPV-positive cervical adenocarcinoma (ADC) detected by laser capture microdissection (LCM). METHODS: Paraffin-embedded specimens diagnosed as ADC between 2005 and 2010 were collected from 9 hospitals in 7 regions across China. HPV genotyping was conducted on paraffin sections using sandwich technique and LCM in order to identify HPV infection in the tumor tissues. HE and p16 immunohistochemistry staining were performed to make histological diagnosis. RESULTS: A total of 169 cervical adenocarcinoma cases were recruited, including 94 cases of mucinous adenocarcinoma (ADC-CX), 9 cases of adenosquamous carcinoma (ASC), 19 cases of minimal deviation adenocarcinoma (ADC-MIN), 14 cases of clear cell adenocarcinoma (ADC-CC), 8 cases of endometrioid adenocarcinoma (ADC-ENDO), 9 cases of serous adenocarcinoma (ADC-SER) and 16 cases of adenocarcinoma not otherwise specified (ADC-NOS). Fourteen types of high risk HPV were detected in the whole tissue section (WTS). HPV16 was the most common type, and the second was HPV18 and HPV52, respectively. Compared with WTS, the HPV-positive rate detected by LCM was lower. The HPV positive rates were significantly different among different subtypes of cervical adenocarcinoma (P<0.001). After LCM, the HPV positive rate was 50.8% and 66.7% in the single infection and multiple, infection groups respectively (P=0.14). The positive rates of p16 was significantly different among different subtypes of cervical adenocarcinoma (P<0.001). p16-positive rate was 73.9% in the HPV-positive samples after LCM, significantly higher than the 38.5% of negative samples (P<0.001). CONCLUSIONS: Laser capture dissection technique can more precisely reflect the HPV distribution in cervical adenocarcinomas. The etiological association between HPV infection and cervical adenocarcinoma occurrence is not as close as that reported in the literature.


Assuntos
Adenocarcinoma de Células Claras/virologia , Carcinoma Adenoescamoso/virologia , Cistadenocarcinoma Seroso/virologia , Microdissecção e Captura a Laser , Papillomaviridae/isolamento & purificação , Infecções por Papillomavirus/diagnóstico , Neoplasias do Colo do Útero/virologia , Adenocarcinoma Mucinoso , Carcinoma Endometrioide , China , Neoplasias do Endométrio , Feminino , Genótipo , Papillomavirus Humano 16/isolamento & purificação , Papillomavirus Humano 18/isolamento & purificação , Humanos , Imuno-Histoquímica , Infecções por Papillomavirus/complicações , Infecções por Papillomavirus/virologia
11.
Int J Neurosci ; 119(2): 291-304, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19125380

RESUMO

The present study investigated the effects of food restriction (FR) on memory and the expression of synapsin I in the brain of young mice. The results showed that 20% FR did not retard the body weight gain of mice, while the 60% and 80% FR reduced the mice's body weight. The memory after 24 hr of learning was not changed by FR, whereas long-term memory was improved significantly in 20% FR mice. In addition, 60% and 80% FR did not impair the mice's memory. The transcriptional expression of synapsin I in mice brain was up-regulated by 20% FR, and down-regulated by 60% and 80% FR.


Assuntos
Aprendizagem da Esquiva/fisiologia , Encéfalo/crescimento & desenvolvimento , Encéfalo/metabolismo , Privação de Alimentos/fisiologia , Memória/fisiologia , Sinapsinas/metabolismo , Envelhecimento/metabolismo , Animais , Peso Corporal/fisiologia , Restrição Calórica/métodos , Regulação para Baixo/fisiologia , Masculino , Transtornos da Memória/metabolismo , Transtornos da Memória/fisiopatologia , Transtornos da Memória/terapia , Camundongos , Regulação para Cima/fisiologia
12.
Chin Med J (Engl) ; 107(4): 260-4, 1994 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8088192

RESUMO

Isoptin SR was used in 65 essential hypertensive patients. 240mg Isoptin SR (German Knoll Pharmaceutical company) per day was used in group A (35 cases) for 6 weeks, and in group B (30 cases) for 24 weeks, BP in group A and B decreased obviously in the first and second week after treatment. Marked effective rate and total effective rate were 65.7% and 74.3% respectively in group A, and 70.0% and 83.3% in group B. There were no significant changes of HR in group A before and after treatment while there was a decrease of HR in group B (P < 0.001). Left atrium (LA) decreased after 6 weeks in group A with an obvious increase of E/A ratio. There was significant decrease in LA, increase in E/A ratio, regression of IVS, LVPW and LVMI, but no changes in SV, CO, LVEF after 24 weeks of treatment of Isoptin SR in group B. E/A ratio was very sensitive and occurred earliest both in group A and group B. Side effects such as headache, dizziness, constipation, insomnia, peripheral oedema, sinus bradycardia occurred mainly in the first week of treatment. These symptoms disappeared gradually in the course of continued administration of Isoptin SR.


Assuntos
Hipertensão/tratamento farmacológico , Hipertrofia Ventricular Esquerda/tratamento farmacológico , Verapamil/uso terapêutico , Adulto , Idoso , Pressão Sanguínea/efeitos dos fármacos , Preparações de Ação Retardada , Feminino , Humanos , Hipertensão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Função Ventricular/efeitos dos fármacos , Verapamil/farmacologia
13.
Cancer Res ; 52(1): 32-5, 1992 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-1727384

RESUMO

A plasmid has been constructed in which the expression of human O6-methylguanine-DNA methyltransferase (MGMT) complementary DNA is driven by the Rous sarcoma virus promoter sequence. We had previously shown that transfection of this plasmid into Chinese hamster ovary (CHO) cells results in the expression of MGMT and in increased cellular resistance to N-methyl-N'-nitro-N-nitrosoguanidine and 1-(2-chloroethyl)-1-nitrosourea (CNU) but not N-nitroso-N-ethylurea (ENU). In the present study, the Rous sarcoma virus promoter-MGMT was transfected into DNA excision repair-deficient CHO UV41 cells to investigate the phenotype associated with MGMT expression in the absence of DNA excision repair. Both the UV41/MGMT and CHO/MGMT cells expressed similar levels of MGMT and exhibited a similar increased resistance to N-methyl-N'-nitro-N-nitrosoguanidine. The UV41 cells were 20-fold more sensitive to CNU than the wild-type CHO cells. Expression of MGMT increased the resistance to CNU about 6-fold in both cell lines, but the difference between the two cell lines attributable to the excision repair defect still persisted. The UV41 cells were 2- to 3-fold more sensitive than the wild-type CHO cells to the monofunctional alkylating agents 1-(2-hydroxyethyl)-1-nitrosourea and ENU, but the MGMT phenotype did not alter sensitivity. This suggests that alkylation at the O6 position of guanine has no role in cytotoxicity of ethylating agents and that monofunctional DNA damage has little role in the cytotoxicity of CNU. Since MGMT can prevent the formation of G-C interstrand cross-links formed by CNU, other excision repair-sensitive DNA adducts must play a major role in the sensitivity of UV41 cells to this bifunctional alkylating agent. These results suggest that DNA intrastrand cross-links may be major contributors to the cytotoxicity of CNU.


Assuntos
Reparo do DNA , DNA/metabolismo , Etilnitrosoureia/análogos & derivados , Etilnitrosoureia/farmacologia , Metiltransferases/metabolismo , Animais , Células CHO/efeitos dos fármacos , Linhagem Celular , Cricetinae , Humanos , Metilnitronitrosoguanidina , O(6)-Metilguanina-DNA Metiltransferase , Fenótipo , Transfecção
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