OBJECTIVETo find out the distributive features of some metabolic genes polymorphisms in Han population of south area of China.

METHODSStudy population was obtained from the controls of a community based case-control study, which included 290 blood relatives (inner control) and 404 non-blood relatives (outer control).

RESULTSFrequencies of CYP1A1, GSTM1 and GSTT1 polymorphisms had no significant difference among confounding factors, such as sex, living areas, stomach cancer family history and history of tobacco smoking etc. Some controls showed significant difference in age group and alcohol drinking which would be adjusted in analysis of the relationship between polymorphisms and cancers. CYP1A1 Ile/Val and Val/Val genotypes were 33.43% and 5.62% respectively, which were similar to other results from Chinese and Japanese, but higher than those from Caucasians in American, Europe and African-Americans. GSTM1 null allele frequency was 53.48% in our population, which showed difference even among Chinese in different areas. GSTT1 null allele frequency was 45.78%, which was significantly higher than that in Caucasians and African-American.

CONCLUSIONThe frequencies of CYP1A1 Ile/Val, Val/Val and GSTT1 null in Han population in south area of China are significantly higher than those in other races, while the ethnic difference of frequency of GSTM1 null is less.

China ; Cytochrome P-450 CYP1A1 ; genetics ; DNA ; genetics ; Female ; Gene Frequency ; Genotype ; Geography ; Glutathione Transferase ; genetics ; Humans ; Male ; Polymorphism, Genetic

OBJECTIVETo study the relationship between polymorphism of inducible Nitric Oxide Synthase (iNOS) gene and the susceptibility of intestinal type stomach cancer and stomach cardia cancer in Chinese people.

METHODSA community-based case-control study was designed. Ninety-three intestinal type of stomach cancer and 50 stomach cardia cancer patients with endoscopy and pathology diagnosis were identified as cases. Two hundred and forty-six controls served as controls.

RESULTSC-->T polymorphism was found in exon 16 of iNOS gene, which changed the coding amino acid from serine to leucine, and formed a recognition site identified by Tsp 509 I restriction enzyme (we called it C-->T polymorphism). The T allele gene frequency in the control group was 13.21%. No statistically significant difference was found between C-->T polymorphism alone and the increased susceptibility to intestinal stomach cancer or stomach cardia cancer. A significant type 2 multiplicative interaction was found in increasing both the risk of intestinal stomach cancer and stomach cardia cancer when both C-->T polymorphism and tobacco smoking exposure existed. An additive interaction model, which showed statistically significant difference, was found to increase only the risk of stomach cardia cancer when CagA antibody shared negative but C-->T polymorphism occurred.

CONCLUSIONC-->T polymorphism of iNOS gene was considered as one of the possible susceptible genes, which specifically increased the risk of tobacco-related but CagA negative types of intestinal stomach cancer and stomach cardia cancer.

Antibodies, Bacterial ; blood ; Antigens, Bacterial ; immunology ; Bacterial Proteins ; immunology ; Genetic Predisposition to Disease ; Humans ; Nitric Oxide Synthase ; genetics ; Nitric Oxide Synthase Type II ; Polymorphism, Genetic ; Stomach Neoplasms ; genetics

Objective To investigate the feasibility of absorbable magnesium alloy screws in atlantoaxial dislocation fixation. Methods Four kinds of screws with triangular, rectangular, trapezoidal and zigzag thread were designed with WE43 magnesium alloy. The finite element simulation analyses were performed on the screw- polyurethane model and atlantoaxial fixation system model. The stress and displacement distributions on the models were obtained. Results The pull-out force simulations were carried out on four kinds of magnesium alloy screws according to ASTM F543 standard specification. The stresses of screws with triangular, rectangular, trapezoidal and zigzag thread were 146.20, 185.22,194.98, 264.55 MPa, respectively. The pull-out strength of the screw with triangular thread was the largest, and the peak stress was the smallest. The magnesium alloy screw with triangular thread used for atlantoaxial fixation could meet the strength requirements of flexion/extension, rotation and bending of the neck. The peak stress of the screw was reduced by 17.16 MPa after adding hydroxyapatite (HA) coating on the surface, and the stress on the screw was within the range of bonding strength between coating and magnesium alloy substrate. Conclusions Under the same loading condition, the screw with triangular thread has good stability and the best pull-out force performance. After heat treatment, the strength of magnesium alloy screw with triangular thread meets the load-bearing requirements for atlantoaxial dislocation fixation. HA coating on screw surface can optimize mechanical properties of the screw, and there exits good bonding strength between the coating and the screw.