instruction:
In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.
question:
Context: By using the techniques of PCR and restriction fragment length polymorphism (RFLP), we established a classification method for HBV genome based on viral S gene of asymptomatic HBV carriers (AsC).', 'By using this method we classified HBV DNA of AsC living in Guangzhou, Shenyang, Beijing and Chongqing.', 'Among the AsC of Guangzhou, genotype B was 32.8%, genotype C 42.7%, mixed genotypes B and C 23.0%, others 1.6%; among the AsC of Chongqing, genotype B was 35.0%, genotype C 40.0%, mixed genotypes B and C 25.0%; among the AsC of Beijing, genotype B was 25.0%, genotype C 50.0%, mixed genotypes B and C 25.0%; among the AsC of Shenyang, genotype B was 11.1%, genotype C 88.9%. The prevalent HBV strains in China are genotype C and genotype B, and genotype C is the main genotype in west China.\Question: Does [ Establishment of a method for classification of HBV genome and it 's application ]?
answer:
The established method for genotyping is simple and convenient. Using this method, we also classified HBV DNA of the patients with chronic hepatitis B and liver cirrhosis living in Guangzhou, and found that mixed genotypes B and C was in 50.0% of the patients detected, suggesting the mixed infection might lead to a severe damage of the liver tissue.

question:
Context: The blasticidin S resistance gene (bsr) is a selectable marker used for gene transfer experiments. The bsr gene encodes for blasticidin S (BS) deaminase, which has a specific activity upon BS. Therefore, its expression is supposed to be harmless in cells. The work reported on herein consisted of experiments to verify a possible toxicity of bsr on mammalian cells, which include several cell lines and primary cultures.', 'Murine keratinocyte BALB/MK and human primary keratinocyte cells transduced with the retroviral vector LBmSN, which has an improved expression system of bsr, namely bsrm, died in five days after the transduction. Meanwhile the control vector LBSN, which expresses bsr, did not provoke cell death. The lethal activity of bsrm was observed only in human keratinocytes and BALB/MK cells among the cell types tested here. Death appears to be mediated by a factor, which is secreted by the BALB/MK transduced cells.\Question: Is over expression of the selectable marker blasticidin S deaminase gene toxic to human keratinocytes and murine BALB/MK cells?
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By our study we demonstrated that the expression of bsrm gene is toxic to human keratinocytes and BALB/MK cells. It is likely over expression of BS deaminase gene is responsible for the death.

question:
Context: The aim of this study was to visualize early stage prostate cancer (Cap) in a clinical setting. In previous studies, the results of magnetic resonance imaging (MRI) for screening Cap have rarely been confirmed by well-designed multisite prostate biopsy.', 'The prostate glands of 90 men with elevated prostate-specific antigen (PSA) were imaged by dynamic contrast-enhanced MRI (DCE-MRI) before transrectal ultrasound-guided 14-cores prostate biopsy. Each core was divided into three subcore fractions (total of 42 fractions) to generate a histological localization diagram, which was compared with localization-visualized DCE-MRI.', "The detection rate of Cap in 57 patients with PSA < 10.0 ng/ml was 36.8% as determined by the initial biopsy. DCE-MRI uncovered 92.9% of the clinically significant Caps and its specificity was 96.2% for the first biopsy session. One case with positive DCE-MRI and a negative primary biopsy was positive with additional biopsies. All of 26 DCE-MRI positive cases had significant Cap, and two of eight patients with histological Cap and negative or equivocal imaging had significant cancer. In total, 9 of 20 cases with DCE-MRI stage T2 underwent radical prostatectomy. All of them had organ-confined disease, although 33-77% (mean 63%) of them were expected to be rated T3 or higher by Partin's table.\Question: Is dynamic contrast-enhanced magnetic resonance imaging ( DCE-MRI ) a useful modality for the precise detection and staging of early prostate cancer?
answer:
DCE-MRI can identify early stage Cap with high sensitivity and specificity, and can predict the histological grade to some extent. DCE-MRI prior to biopsy should be applied to younger patients with surgical indications. Otherwise, we recommend the definitive diagnosis of Cap by utilizing DCE-MRI alone.