Objective To investigate the interseed dose attenuation for multiple 125I seeds.Methods Monte Carlo simulation was done by Geant 4 to investigate the dose distribution of single seed and multiple seeds.The results were compared with the dose calculation method from TG43-U1 and examined by experiments.Results The difference of single seed dose distribution between Monte Carlo method and line source model was ± 3％.The difference between Monte Carlo method and experiment result was ± 5％.The interseed dose attenuation of multiple seeds at the interesting points was 3.8％ to 13.2％ and the average interseed dose attenuation was 7.2％.The difference of experiment result and Monte Carlo result was less than 6％.Conclusions The interseed attenuation is about 7％ and the maximum value may be larger than 13％ for multiple seeds.The interseed dose attenuation may be larger in tissue.So it is not accurate to calculate the dose distribution by using TG43-U1.

Objective:This study aimed to detect the special methylation profile in peripheral blood for hepatocellular carcinoma (HCC). Methods:The methylation status of 12 tumor suppressor genes (TSGs) in the plasma of 55 HCCs and 54 chronic liver diseases (CLDs) was tested by methylation-specific PCR (MSP). Results:In HCC, the methylation frequencies were 78.18%in APC, 63.64%in cyclin D2, 58.18% in TFPI2, 49.09% in DKK3, 49.09% in GSTP1, 47.27% in p16, 40.00% in Sigma 14-3-3, 18.18% in SFRP2, 16.36% in ppENK, 9.09% in DKK2, 7.27% in NPTX2, and 5.45% in LHX1. In CLD, the methylation frequencies were 27.78% in APC, 22.22%in cyclin D2, 7.41%in TFPI2, 3.70%in DKK3, 16.67%in GSTP1, 37.04%in p16, 37.04%in Sigma 14-3-3, 11.11%in SFRP2, 20.37%in ppENK, 7.41%in DKK2, 7.41%in NPTX2, and 9.26%in LHX1. The methylation frequencies of APC, cyclin D2, TFPI2, DKK3, and GSTP1 were higher in HCC than in CLD (P<0.01). The methylation index (MI) of the five-gene methylation profile was statistically higher in HCC (median, 0.6;IQR, 0.4-0.8) than CLD (median, 0.2;IQR, 0-0.2) (P<0.01). In HCC, MI was statistically related to the patient's age. Older patients with HCC had a higher MI. No significant correlation was observed between MI and other clinicopathological data. Moreover, MI was not related to the disease free survival and the overall survival in HCC. Conclusion:This five-gene methylation profile may be a promising biomarker for the assistant diagnosis of HCC.

AIM :To investigate the association of primary open-glaucoma (POAG), intraocular pressure (IOP) and systemic blood pressure in a rural population aged 50 years old or above in Shaanxi Province, China.METHODS: In the population-based, cross-sectional study, 1 775 (83.53%) residents, aged 50 years old or above, from 3 counties of Shaanxi Province, China, undertook an interview with a standard questionnaire and a detailed eye examination, including logarithm of the minimum angle of resolution visual acuity, slit-lamp biomicroscopy, applanation tonometry and dilated fundus examination. Two blood pressure reading in the sitting position were taken. Gonioscopy was performed if a narrower peripheral anterior chamber (less than one fourth of the corneal thickness) was indicated. Automated visual field testing was performed by participants assessed to have suspicion of glaucomatous disc damage or if IOP was 22mmHg or higher.RESULTS: IOP significantly correlated with systemic blood pressure, and both IOP and systolic blood pressure increased significantly with increasing age. No association between POAG and hypertension was found. The frequency of POAG increased significantly with lower diastolic perfusion pressure.CONCLUSION: Data in our study are accordance with those reported in other population-based studies, and confirm that lower diastolic perfusion pressure is a significant risk factor for primary open angle glaucoma.

AIM: To assess the prevalence and risk factors for age-related macular degeneration (AMD) in a rural population in Shaanxi Province of China.METHODS: A total of 2 835 (81.00%) people aged 40 years old or more, from Fuping county, Jingbian county and Yang county of Shaanxi Province, China, underwent a comprehensive interview and a relative eye examination. The present of AMD was classified into neovascular AMD (NV) and pure geographic atrophy (GA) by using direct ophthalmoscopy for fundus examination according to International Classification System.RESULTS: The prevalence (95% CI) of AMD was 3.00% (2.42, 3.71) in this population, of which NV accounted for 1.45% (1.05, 1.98) and 1.55% (1.14, 2.10)for GA. The prevalence of AMD increased significantly with increasing age (P ＜0.001). AMD was present in 0.47% of participants aged 40 to 49 years, rising to 11.90% of participants older than 80 years, of which the corresponding data increased from 0.28% to 4.76% for NV and from 0.19% to 7.14% for GA. No significant difference was found in the prevalence of NA and GA between genders in this population. With multiple logistic analyses, apart from advancing age, only smoking was found to have a strong association with any type of AMD.CONCLUSION: The prevalence of AMD in the rural population of Shaanxi Province of China is lower than that reported from other population-based studies in different provinces of China, less than that reported in whites, more than that reported in blacks. Except increasing age, smoking is also a significant well-known risk factor for AMD.

· AIM: To assess the prevalence and related risk factors for primary angle-closure glaucoma in a rural population for 40 years of age or older in Shaanxi Province.· METHODS: By using a stratified, cluster-based, random sampling technique, 8 500 persons of all ages were selected randomly, including 3 500 those aged 40 years or more, from the North, the South and the Middle of Shaanxi Province in Western China from July to December in 2003. All participants had an interview with a standard questionnaire and those questions related to glaucoma of previous diagnosis and treatment, family history and outbreak history. Then a detailed and relative eye examination was performed, including logarithm of the minimum angle of resolution visual acuity, external eye examination with slit-lamp biomicroscopy and fundus examination. The intraocular pressure was measured with Perkins applanation tonometry to those persons aged 50 years old or more and those with suspected increased IOP. A further examination was performed to those persons with suspicious glaucoma, including repeated tonometric examination, gonioscopy, dark room test, automated visual field testing, et al.·RESULTS: 6 815 of the eligible 8 500 persons of all ages were interviewed and examined from July to December in 2003, a response rate of 80.18%, including 2835 of the eligible 3 500 persons of 40 years old or more with a response rate of 81.00%. According to Van Herick method, the percentage of shallow peripheral anterior chamber was 13.6%, of which 10.4% was in grade 2, 3.0% in grade 1, and 0.2% in grade 0. In this rural population for 40 years of age or older 31 participants were found to have primary angle-closure glaucoma, with the prevalence of 1.09%. With multiple logistic analyses, the prevalence increased significantly with age (P=0.008), whereas no significant difference (Pgender=0.180, Peducation=0.199) was found in the rate with gender and education, although women and illiteracy seemed to be at increased risk of the disease (OR: 1.77, 95%CI,0.77-4.10; OR: 1.71, 95%CT, 0.76-3.87). Of 31 participants, 21 persons (67.74%) had not been previously diagnosed and treated. Of 10 participants previously diagnosed, 6 (60%) had been received peripheral iridectomy; nevertheless, no any other treatments were performed. 48.39% participants suffered from visual impairment in various degrees, of which the percentage of blindness in either eye accounted for 29.03%. Of those with primary angle-closure glaucoma, 22 persons (70.97%) were classified as having chronic from of the disease.· CONCLUSION: In this rural population in Shaanxi Province of China, the rate of occludable angles is 13.6%, more common than that reported previously in other Chinese populations. The prevalence of primary angle-closure glaucoma is close to that from other Asian populations, increasing with age. A majority of glaucoma was undiagnosed and untreated previously.

· AIM: To assess the prevalence and related risk factors of primary open angle glaucoma (POAG) in a rural population in Shaanxi Province.· METHODS: By using a stratified, duster-based, random sampling technique, 8 500 persons of all ages were selected randomly, from the North, the South and the Middle of Shaanxi Province from July to December in 2003. All participants had an interview with a standard questionnaire and those questions related to glaucoma of previous diagnosis and treatment, family history and outbreak history. Then a detailed and relative eye examination was performed, including logarithm of the minimum angle of resolution visual acuity, external eye examination with slit-lamp biomicroscopy and fundus examination. The intraocular pressure was measured with Perkins applanation tonometry to those persons aged 50years old or more and those with suspected increased IOP. A further examination was performed to those persons with suspicious glaucoma, including repeated tonometric examination, gonioscopy, dark room test, automated visual field testing, et al.· RESULTS: 6 815 of the eligible 8 500 persons of all ages were interviewed and examined from July to December in 2003, a response rate of 80.18%. 9 participants were found to have POAG, with the prevalence of 0.13%, age ranging from 38 to 80 years (mean year:62.0). In those aged 30 years old or more, the prevalence of the disease was 0.23%, 0.28% and 0.39% for those more than 40 and 50 years old, respectively. The rate of suspicious POAG was 0.18% (12 cases) with age ranging from 35 to 77 years (mean year: 54.7). With multiple logistic analyses, the prevalence increased significantly with age (P=0.023). Other than increasing age, myopia was also a strong risk factor for POAG. Of 9participants with POAG, only 2 cases (22.22%) had been previously diagnosed. No one with POAG was received any treatment previously. 66.67% (6 cases) participants with POAG suffered from visual impairment in various degrees secondary to POAG. The percentage of blindness in either eye was 33.33%.· CONCLUSION: The prevalence of POAG is close to that from other Chinese populations, increasing with age. A majority of glaucoma was undiagnosed and untreated previously.

ObjectiveTo investigate the diagnostic value of transgastic peritoneoscopy for ascites of unknown aetiology.MethodsTransgastric peritoneoscopy was performed on 7 patients with ascites of unknown aetiology.Diagnosis and complications were both recorded.ResultsDiagnosis of all the 7 patients were confirmed after transgastric peritoneoscopy,among whom 6 ( 85.7％ ) were found to have tuberculosis peritonitis,and 1 ( 14.3％ ) with liver disease.All patients recovered after the operation.No intraoperative or postoperative complications occurred.ConclusionTransgastric peritoneoscopy is a valuable diagnostic method for ascites of unknown aetiology.

ObjectiveTo evaluate the efficacy and safety of endoscopic submucosal dissection (ESD) for the treatment of laterally spreading tumors (LST).MethodsESD was applied to remove 32 colorectal LSTs larger than 2 cm.The characteristics of the tumors and clinical results including en bloc resection rate,procedure time,complication and recttrrence rates were retrospectively evaluated.Results The lesions ranged from 2.5 cm to 8.0 cm,with a mean diameter of 4.1 ± 2.1 cm.En bloc resection wasachieved in 29 patients (90.6％ ) with a mean operation time of 75.7 ±66.0 min.Immediate arerial bleeding occurred in 5 ( 15.6％ ) cases but was stopped successfully by clips or coagulations.Late bleeding occurred in 2 ( 6.2％ ) and perforations in 3 (9.4％ ),which were closed successfully by clips without surgery.Pathological diagnosis revealed low-grade intraepithelial dysplasia in 19 (59.4％ ),high-grade intraepithelial dysplasia in 6 ( 18.8％ ),and carcinomas in 7 (21.9％).The lesions were restricted in mucosal layer in 25 (78.1％ ),infiltrating into sm1 layer in 5 ( 15.6％ ) and sm2 layer in 2 (6.2％ ),and the later 2 were referred to surgery.Twenty patients were followed up for 3-12 months,and no local recurrence was found..ConclusionESD was an effective and safe therapy for colorectal LST larger than 2 cm.

Objective To make a comparison for the neutrophils prepared either by induction of differentiation of myeloid leuke-mia cell line,or by separation and purification of peripheral blood cells,or by induction of myeloid differentiation of peripheral blood stem cells.Methods NB4 cells were induced differentiation by 1μmol/L all-trans retinoic acid (ATRA)to mature granulo-cytes;neutrophils were separated and purified from peripheral blood by lysis of red blood cells followed by negative selection using magnetic bead-labeled antibodies;hematopoietic stem cells were separated and purified from peripheral blood by Percoll gradient centrifugation followed by negative selection using magnetic bead-labeled antibodies,and were induced to myeloid differentiation by GM-CSF and G-CSF.Morphology and purity of neutrophils prepared by these three methods were studied by means of MGG stai-ning.CD18 protein expression and subcellular distribution were studied by means of immunofluorescence staining.Results Purity of neutrophil was above 40% by induction of differentiation of NB4 cells,and was about 90% if purified from peripheral blood,and was above 70% if induced by myeloid differentiation of peripheral blood stem cells.There was no obvious difference for CD18 ex-pression in neutrophils prepared by these three methods,and staining of CD18 had a dotted pattern distributed in these cells.Con-clusion Peripheral blood neutrophils prepared by lysis of red blood cells followed by negative selection using magnetic bead-labeled antibodies are with high purity and viability which is suitable for immediate test of neutrophils from fresh blood.Neutrophils pre-pared by myeloid differentiation of hematopoietic stem cell are with high viability and last for days,which can be used in long test for neutrphils.

Objective To explore the feasibility of culturing dermal papillae cells (DPC) of hu- man hair in a serum-flee medium,and to observe the growth characteristics of these cells.Methods Cell culture flasks (plates) were pretreated with fibronectin,and DPC (2nd passage) were incubated with Williams E serum-flee medium supplemented with insulin-transferrin-selenite (ITS).Cells were observed by an inverted phase-contrast microscope.Proliferation of DPC was evaluated with 3-(4,5-dimethylthia- zol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and by their growth curve.Results In a serum-free medium,2nd passage DPC adhered to the flask surface within two to four hours of incubation; two to three days later,confluence,of the cells was observed,without noticeable proliferation.Four days later,cell connection was interrupted,isolated cells or cell clusters were seen,and detachment of some cells from the flask surface was observed.One to two weeks later,most cells had died.After incubation with 4% bovine serum for ten hours,cell proliferation was observed surrounding the remaining viable cell colonies. DPC growth curve showed stagnant phase and slow growth phase;however,log growth phase was not ob- served.Conclusion DPC could be successfully cultured in serum-free medium.However,the culture con- dition needs to be further optimized.