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.
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Question: Context: The aim of this study was the analysis of total, early and late complications following venous access port implantation between 1998 and 2008 at the Department of Surgery of the University of Rostock, Germany. A comparison between different implantation techniques addressing success rate, complication rate and duration of operation was performed. These results were further analysed in regard to the level of training of the participating surgeons.', 'A retrospective analysis of 1423 venous access port implantations between 1998 and 2008 was performed.', "The rate of total complications was 13.8%. Among 4.7% early complications pneumothorax was the most common. The rate of late complications was 9.1%. Most common were infection (4.9%) followed by dysfunction of the catheter (3.5%). 1322 venous access port implantations were performed using puncture of the subclavian vein and Seldinger's technique. 101 operations were performed by direct access through dissection of the cephalic vein and open introduction of the catheter. Operation time in the open group was significantly longer than in the puncture group (46.5min vs. 38.7min, p=0.005). There were significantly more late complications (9.6% vs. 2%, p=0.01) and total complications (14.5% vs. 4%, p=0.005) in the puncture group vs. the open access group. Primary success rates of open access vs. puncture were 100% and 96.8%, respectively. The rate of complications was independent of the experience status of the surgeon. However, the rate of total and late complications significantly decreases with number of performed operations.\Question: Is [ Venous Access Port Implantation an Ideal Teaching Operation - An Analysis of 1423 Cases ]?

Answer: Venous port implantation is a relatively simple procedure despite its possible complications. An open access technique is safer than puncture. The rate of complications significantly decreases with increasing number of performed operations. Therefore venous port implantation and especially the open access method is an ideal teaching operation in a structured surgical training programme.

Question: Context: Cytokeratin 19 is significant for indicating cancer cells, and Cyfra 21-1 is a fragment of cytokeratin 19. This retrospective study was designed to define the prognostic value of serum Cyfra 21-1 in epithelial ovarian cancers (EOC).', 'Serum Cyfra 21-1 concentration was obtained from 42 patients with EOC prior to treatment. Various prognostic aspects were examined using univariable and multivariable analyses. The standard serum marker cancer antigen 125 was measured simultaneously and compared in this analysis.', 'Serum levels of both Cyfra 21-1 and cancer antigen 125 were associated with positive retroperitoneal lymph nodes and platinum resistance; higher levels of Cyfra 21-1 (3.0ng/mL as the cut-off) were associated with shorter disease-free survival (16 months vs. 28 months, p=0.001) and overall survival (29 months vs. 41 months, p=0.007) than lower levels. Further univariable analysis showed that Cyfra 21-1, poor differentiation, and retroperitoneal lymph node metastasis were related to platinum resistance and mortality. Multivariable analysis indicated retroperitoneal lymph node metastasis and serum Cyfra 21-1 were independent risk factors for both disease-free survival and overall survival.\Question: Is serum cytokeratin-19 fragment ( Cyfra 21-1 ) a prognostic indicator for epithelial ovarian cancer?

Answer: The pretreatment level of serum Cyfra 21-1 had remarkable prognostic significance for EOC, indicating poor survival when it was elevated above 3.0ng/mL.

Question: Context: The objective of this study was to determine the quantitative influence of vitamin K epoxide reductase complex subunit 1 (VKORC1) and cytochrome P450 2C9 (CYP 2C9) polymorphisms on warfarin dose requirements in Turkish patients.', 'A total of 205 patients taking warfarin for >2 months were enrolled in the study. Deoxyribonucleic acid (DNA) samples from these patients were genotyped for polymorphisms in VKORC1 and CYP2C9 genes. A linear regression analysis was used to determine the independent effects of genetic and non-genetic factors on mean warfarin dose requirements.', 'The VKORC1 promoter polymorphism (3673 G>A) was associated with differences in weekly mean varfarin dose: for GG genotype the dose was 43.18 mg/week, for GA genotype 33.78 mg/week and for AA genoype 25.83 mg/week (P < 0.0001). Patients who carried VKORC1 and CYP2C9 variants needed a 40% lower mean weekly warfarin dose compared to wild types. Variables associated with lower warfarin dose requirements were VKORC1 3673 AA or GA genotype (both P < 0.0001), one or two CYP2C9 variant alleles (both P < 0.0001), increasing age (P < 0.0001) and non-indication of venous thromboembolism for warfarin therapy (P = 0.002).\Question: Are vKORC1 and CYP2C9 polymorphisms associated with warfarin dose requirements in Turkish patients?

Answer:
Polymorphisms in VKORC1 and CYP2C9 genes were important determinants of warfarin dose requirements in Turkish patients.