[Three-dimensional analysis of maxillary dentition during molar distalization with clear aligners under different movement designs: an in vitro experiment].

Objective: To investigate the three-dimensional force in the maxillary dentition under different movement designs for molar distalization with clear aligners Methods: Three groups were designed: simultaneous movement group (simultaneous distalization of maxillary first and second molars), second molar movement group (distalization of maxillary second molars) and first molar movement group (distalization of maxillary first molars). Ten clear aligners were made in each group, and the displacement was designed to be 0.2 mm. A force sensing device was established to measure the three-dimensional force on the upper dentition with the clear aligner. The device contained a model of the maxillary dentition consisting of 14 teeth, each tooth connected to an individual sensor. After the clear aligner was fitted, the data of 14 sensors were collected and analyzed using computer analysis software. The moving teeth were taken as the target teeth, and the rest of the teeth were anchorage. The data of the three-dimensional force in the three groups in each tooth position were measured and compared. Results: The sagittal forces on the first and second molars in the simultaneous movement group were (5.61±0.94) and (5.81±1.08) N, respectively, which were significantly smaller than those of the target teeth in the same position in other groups (P<0.05). The second molars in the first molar movement group received a sagittal reaction force, which was (-6.73±1.99) N. The anterior teeth in the three groups were all subjected to sagittal reaction force, and the force value was in a range of (-3.33 to 0.46) N. In the coronal direction, the second premolars of the simultaneous movement group received the reaction force in the palatal direction, and the force value was (-2.17±1.06) N. The first molars in the second molar movement group were also subjected to palatal reaction force of (-1.99±0.70) N. The second molars and second premolars in the first molar movement group were also subjected to palatal reaction force, which were (-2.85±0.57) and (-1.85±0.74) N, respectively. Compared with the sagittal and coronal forces, the target teeth and anchorage teeth in the three groups were less stressed in the vertical direction. Conclusions: The first and second molars distalized simultaneously, the correction force in the sagittal direction was relatively small. When first molar was moved distally alone, a greater reaction force in the sagittal direction was exerted on the second molar. Buccal displacement of the adjacent anchorage teeth should be designed to counteract the palatal reaction force on the anchorage teeth as the molars moved distally.

IFN-γ inhibits ovarian cancer progression via SOCS1/JAK/STAT signaling pathway

PurposeOvarian cancer (OC) is a common malignancy, and IFN-γ, a multifunctional cytokine, is unveiled to impede the multiplication and enhance apoptosis in diverse tumor cells in previous research. Nonetheless, its function and mechanism in OC are blurred.MethodsOC cell lines SKOV3 and OVCAR3 were dealt with different concentrations (0–40 ng/ml) of IFN-γ. CCK-8 experiment was utilized to examine cell multiplication; Flow cytometry was executed to detect apoptosis and cell cycle; Wound healing assay was utilized to detect cell migration; and Transwell experiment was implemented to examine cell invasion. qRT-PCR analysis was applied to detect STAT5, STAT3, JAK2 and JAK3 mRNA expression in OC cell lines. Western blot experiment was applied to detect the protein and phosphorylation levels of SOCS1, STAT5 and STAT3.ResultsIFN-γ suppressed OC cell multiplication in a concentration-dependent manner. Relative to the control group, IFN-γ restrained OC cell migration, invasion, enhanced apoptosis and prevented cell transformation from G0/G1 to S phase. Further analysis revealed that IFN-γ up-modulated SOCS1 expression and impeded STAT5 and STAT3 protein phosphorylation levels, and knockdown of SOCS1 partially counteracted the inhibitory effect of IFN-γ on STAT5 and STAT3 protein phosphorylation levels.ConclusionIFN-γ represses OC progression by facilitating SOCS1 to suppress STAT3 and STAT5 protein phosphorylation.

IFN-γ inhibits ovarian cancer progression via SOCS1/JAK/STAT signaling pathway.

PURPOSE: Ovarian cancer (OC) is a common malignancy, and IFN-γ, a multifunctional cytokine, is unveiled to impede the multiplication and enhance apoptosis in diverse tumor cells in previous research. Nonetheless, its function and mechanism in OC are blurred. METHODS: OC cell lines SKOV3 and OVCAR3 were dealt with different concentrations (0-40 ng/ml) of IFN-γ. CCK-8 experiment was utilized to examine cell multiplication; Flow cytometry was executed to detect apoptosis and cell cycle; Wound healing assay was utilized to detect cell migration; and Transwell experiment was implemented to examine cell invasion. qRT-PCR analysis was applied to detect STAT5, STAT3, JAK2 and JAK3 mRNA expression in OC cell lines. Western blot experiment was applied to detect the protein and phosphorylation levels of SOCS1, STAT5 and STAT3. RESULTS: IFN-γ suppressed OC cell multiplication in a concentration-dependent manner. Relative to the control group, IFN-γ restrained OC cell migration, invasion, enhanced apoptosis and prevented cell transformation from G0/G1 to S phase. Further analysis revealed that IFN-γ up-modulated SOCS1 expression and impeded STAT5 and STAT3 protein phosphorylation levels, and knockdown of SOCS1 partially counteracted the inhibitory effect of IFN-γ on STAT5 and STAT3 protein phosphorylation levels. CONCLUSION: IFN-γ represses OC progression by facilitating SOCS1 to suppress STAT3 and STAT5 protein phosphorylation.

[Clinicopathological analysis in patients with chronic hepatitis B virus infection in immune tolerant phase].

Objective: To analyze the liver pathology, clinical characteristics and influence factors in patients with chronic hepatitis B virus (HBV) infection in immune tolerant phase (IT). Methods: The clinical data of 273 patients in IT phase who underwent liver biopsy from January 2015 to December 2019 were included in this study. The correlation between liver pathological changes and clinical features was analyzed. Results: There were 43 cases (15.75%) with liver histologic activity ≥ G2, 30 cases (10.99%) with liver fibrosis ≥ S2, and 55 cases (20.15%) with liver pathology ≥ G2 and/or ≥ S2. A total of 17.95% patients had liver steatosis. The majority (98.17%) of tissue samples were positive for HBsAg staining, while only 79.49% were positive for HBcAg. The characteristics of liver pathology were comparable in men from women patients. The differences of G and S were not statistically significant according to different HBsAg positivity, while those were statistically significant according to different HBcAg positivity. By univariate and multivariate analysis, the independent risk factors of pathological severity were HBcAg intensity, HBeAg level, and age. However, the differences of liver histologic activity and fibrosis were not statistically significant between those younger than 30 years old group from those older than 30 years old, neither between those younger or older than 40. Although the diagnostic value of liver inflammation and fibrosis 5 (LIF-5) was better than that of aspartate aminotransferase-to-platelet ratio index (APRI) and fibrosis 4 score (FIB-4), three diagnostic models for predicting the pathological severity were not strong enough (all area under the curves<0.8). Only the specificity of LIF-5 for predicting≥ G2, ≥ G2 and/or ≥ S2 was over 80%. Conclusions: Approximately 20% patients with chronic HBV infection in IT phase have progressive liver inflammation or fibrosis. The intensity of liver HBcAg and HBeAg level are negatively correlated with the severity of disease. The diagnostic models or most clinical indicators have low predictive effect for chronic HBV infections in IT phase.

Prognostic model for identifying candidates for hepatectomy among patients with hepatocellular carcinoma and hepatic vein invasion.

BACKGROUND: Hepatic vein tumour thrombus (HVTT) is a major determinant of survival outcomes for patients with hepatocellular carcinoma (HCC). An Eastern Hepatobiliary Surgery Hospital (EHBH)-HVTT model was established to predict the prognosis of patients with HCC and HVTT after liver resection, in order to identify optimal candidates for liver resection. METHODS: Patients with HCC and HVTT from 15 hospitals in China were included. The EHBH-HVTT model with contour plot was developed using a non-linear model in the training cohort, and subsequently validated in internal and external cohorts. RESULTS: Of 850 patients who met the inclusion criteria, there were 292 patients who had liver resection and 198 who did not in the training cohort, and 124 and 236 in the internal and external validation cohorts respectively. Contour plots for the EHBH-HVTT model were established to predict overall survival (OS) rates of patients visually, based on tumour diameter, number of tumours and portal vein tumour thrombus. This differentiated patients into low- and high-risk groups with distinct long-term prognoses in the liver resection cohort (median OS 34·7 versus 12·0 months; P < 0·001), internal validation cohort (32·8 versus 10·4 months; P = 0·002) and external validation cohort (15·2 versus 6·5 months; P = 0·006). On subgroup analysis, the model showed the same efficacy in differentiating patients with HVTT in peripheral and major hepatic veins, the inferior vena cava, or in patients with coexisting portal vein tumour thrombus. CONCLUSION: The EHBH-HVTT model was accurate in predicting prognosis in patients with HCC and HVTT after liver resection. It identified optimal candidates for liver resection among patients with HCC and HVTT, including tumour thrombus in the inferior vena cava, or coexisting portal vein tumour thrombus.

ANTECEDENTES: La trombosis tumoral de la vena hepática (hepatic vein tumour thrombus, HVTT) es un determinante importante de los resultados de supervivencia en pacientes con carcinoma hepatocelular (hepatocellular carcinoma, HCC). Se desarrolló el modelo llamado Eastern Hepatobiliary Surgery Hospital (EHBH)-HVTT para predecir el pronóstico de los pacientes con HCC y HVTT después de la resección hepática (liver resection, LR), con el fin de identificar los candidatos óptimos para LR entre estos pacientes. MÉTODOS: Se incluyeron pacientes con HCC y HVTT de 15 hospitales en China. El modelo EHBH-HVTT con gráfico de contorno se desarrolló utilizando un modelo no lineal en la cohorte de entrenamiento, siendo posteriormente validado en cohortes internas y externas. RESULTADOS: De 850 pacientes que cumplieron con los criterios de inclusión, hubo 292 pacientes en el grupo LR y 198 pacientes en el grupo no LR en la cohorte de entrenamiento, y 124 y 236 en las cohortes de validación interna y externa. Los gráficos de contorno del modelo EHBH-HVTT se establecieron para predecir visualmente las tasas de supervivencia global (overall survival, OS) de los pacientes, en función del diámetro del tumor, número de tumores y del trombo tumoral de la vena porta (portal vein tumour thrombus, PVTT). Esto diferenciaba a los pacientes en los grupos de alto y bajo riesgo, con distinto pronóstico a largo plazo en las 3 cohortes (34,7 versus 12,0 meses, 32,8 versus 10,4 meses y 15,2 versus 6,5 meses, P < 0,001). En el análisis de subgrupos, el modelo mostró la misma eficacia en la diferenciación de pacientes con HVTT, con trombo tumoral en la vena cava inferior (inferior vena cava tumour thrombus, IVCTT) o en pacientes con PVTT coexistente. CONCLUSIÓN: El modelo EHBH-HVTT fue preciso para la predicción del pronóstico en pacientes con HCC y HVTT después de la LR. Identificó candidatos óptimos para LR en pacientes con HCC y HVTT, incluyendo IVCTT o PVTT coexistente.

[Role and potential value of circular RNAs in the occurrence of primary hepatic cancer].

Circular RNA is a class of non-coding RNAs, which are covalently closed and circular at both ends, showing dissimilar characteristics from linear RNA. Several studies have shown that circular RNAs play an important role in the occurrence and development of primary hepatic cancer. By combining with the latest research progress of this field at home and abroad, we summarized the mechanism regulating the occurrence and development of liver cancer, abnormal expression, and as potential molecular markers for disease diagnosis and treatment.

Effects of low molecular weight heparin in the treatment of venous thromboembolism in patients with gastrointestinal cancer.

This study aimed to observe the safety and effectiveness of different dosing regimens of low molecular weight heparin in the prevention of venous thromboembolism (VTE) and to provide a guideline for the treatment of individualized VTE prophylaxisin patients with postoperative gastrointestinal tumors. Forty patients with high risk for VTE after surgery for gastrointestinal tumors treated in Hongqi Hospital of Mudanjiang Medical University in the period October 2016 to May 2017 were included in the study. The patients were randomly divided into two groups, group A that included 24 patients treated with low molecular weight heparin (LMWH) 5000 IU every 12 hours, and group B comprised of 16 patients treated with LMWH 5000IU every 24 hours. On the seventh day post-surgery anti-Xa activity values reached effective anticoagulation (>0.5 IU/mL) in both groups. In group A, there was one case of anti-Xa activity exceeding 1.0 IU/mL, but no bleeding complications occurred. Using LMWH 5000 IU subcutaneous injection every 12 hours could also prevent postoperative VTE of gastrointestinal tumor, but the risk of bleeding complications is higher compared with 24-hour administration. Monitoring of plasma D-dimer within 7 days after gastrointestinal surgery did not show a great value for VTE monitoring. This study demonstrated that subcutaneous injection of LMWH can prevent VTE after gastrointestinal tumor surgery and provide a new alternative for VTE prevention.

DNA repair gene XRCC3 T241M polymorphism and susceptibility to hepatocellular carcinoma in a Chinese population: a meta-analysis.

Numerous studies have evaluated the association between the X-ray repair complementing defective repair in Chinese hamster cells 3 (XRCC3) T241M polymorphism and hepatocellular carcinoma (HCC) risk. However, the results of such investigations have proved inconsistent. Therefore, we performed a meta-analysis of the association between this polymorphism and HCC risk in the Chinese population. Published literature from PubMed and China National Knowledge Infrastructure databases was retrieved, and a total of 5 case-control studies consisting of 2967 patients and 3874 controls were included in this meta-analysis, which revealed a significant association between the XRCC3 T241M polymorphism and HCC risk (TT vs MM: OR = 6.54, 95%CI = 2.14-19.99; TT vs MT: OR = 4.72, 95%CI = 2.26-9.86; dominant model: OR = 0.38, 95%CI = 0.26-0.57; recessive model: OR = 1.27, 95%CI = 0.99-1.62). In a subgroup analysis by sample size (number of subjects > 1000), similar results were obtained. Thus, XRCC3 T241M polymorphism may constitute a risk factor for HCC in the Chinese population.

Exendin-4 shows no effects on the prostatic index in high-fat-diet-fed rat with benign prostatic hyperplasia by improving insulin resistance.

Benign prostatic hyperplasia (BPH) is a prevalent disease globally, and accumulating evidence has indicated an association between BPH, insulin resistance (IR) and diabetes. Exendin-4 is widely used in clinics, which could enhance the proliferation of pancreatic ß cells. The ability of exendin-4 to promote tumorigenesis has been of concern, and whether exendin-4 would enhance the propagation of BPH is not fully understood. We aimed to determine whether glucagon-like peptide-1 receptors (GLP-1Rs) were expressed in rat prostate and to determine the effect of exendin-4 on prostate of BPH. Male Wistar rats were used and assigned to six groups: normal diet (ND), high-fat diet (HFD), HFD + exendin-4, HFD + BPH, HFD + BPH + exendin-4 and HFD + BPH + rosiglitazone group. After castration, steroids were injected subcutaneously for 4 weeks to induce BPH. Rats were kept on high-fat diet to induce IR. Treatment groups were treated with exendin-4 and rosiglitazone. Prostatic index and HOMA-IR index were used to evaluate the prostatic hyperplasia status and the degree of IR respectively. The expression of GLP-1R was indicated not only by immunohistochemistry, but also by Western blot analysis. The expression of GLP-1R was significantly higher, and HOMA-IR index and body weight significantly decreased after administration of exendin-4. However, no significant differences in the prostatic index were observed between exendin-4 treatment groups and non-exendin-4 treatment groups. Prostatic index was not influenced by exendin-4 maybe by improving IR and weight loss.

Nonmuscle myosin IIA is associated with poor prognosis of esophageal squamous cancer.

Nonmuscle myosin IIA (myosin IIA) is a force-producing protein involved in the process of cell migration. Its expression has been considered as a bad prognostic indicator in stage I lung adenocarcinoma. However, the expression and clinical significance of myosin IIA in esophageal cancer has not been explored. In this study, we investigate the expression level of myosin IIA in 50 esophageal squamous cancer and 30 adjacent normal esophageal tissues by immunohistochemical staining and correlated its expression with clinicopathological features. Myosin IIA was expressed in all esophageal squamous cancer tissues (100%) and 8 of 30 adjacent normal tissues (26.7%, P = 0.000). In cancer tissues, elevated myosin IIA expression level was significantly correlated with increasing metastatic lymph nodes, poorer cancer differentiation, and advanced tumor stage. Further univariate analysis suggested that strong myosin IIA expression was associated with a significantly shorter overall survival (P = 0.021). In addition, MYH9 SiRNA was transfected into esophageal squamous cancer cell line (KYSE-510) to study the role of myosin IIA in cell migration. SiRNA-mediated depletion of myosin IIA in KYSE-510 cells significantly increased cell-matrix adhesion and attenuated cell migration ability (P = 0.000). In conclusion, these findings indicate that overexpression of myosin IIA may contribute to the progression and poor prognosis of esophageal squamous cancer, and this effect may be associated with increased cancer cell migration.

Gastric dysplasia and gastric cancer: Helicobacter pylori, serum vitamin C, and other risk factors.

BACKGROUND: Gastric cancer is generally thought to arise through a series of gastric mucosal changes, but the determinants of the precancerous lesions are not well understood. To identify such determinants, we launched a follow-up study in 1989-1990 among 3433 adults in Linqu County, China, a region with very high rates of gastric cancer. METHODS: Data on cigarette smoking, alcohol consumption, and other characteristics of the participants were obtained by interview in 1989-1990, when an initial endoscopy was taken. At study entry, antibodies to Helicobacter pylori were assayed in 2646 adults (77% of people screened), and levels of serum micronutrients were measured in approximately 450 adults. Follow-up endoscopic and histopathologic examinations were conducted in 1994. Antibodies to H. pylori, levels of serum micronutrients, and other baseline characteristics were compared between subjects whose condition showed progression to dysplasia or gastric cancer from study entry to 1994 and subjects with no change or with regression of their lesions over the same time frame. All P: values are two-sided. RESULTS: The presence of H. pylori at baseline was associated with an increased risk of progression to dysplasia or gastric cancer (odds ratio [OR] = 1.8; 95% confidence interval [CI] = 1.2-2.6). The risk of progression to dysplasia or gastric cancer also was moderately increased with the number of years of cigarette smoking. In contrast, the risk of progression was decreased by 80% (OR = 0.2; 95% CI = 0.1-0.7) among subjects with baseline ascorbic acid levels in the highest tertile compared with those in the lowest tertile, and there was a slightly elevated risk in those individuals with higher levels of alpha-tocopherol. CONCLUSIONS: H. pylori infection, cigarette smoking, and low levels of dietary vitamin C may contribute to the progression of precancerous lesions to gastric cancer in this high-risk population.

Blood type and family cancer history in relation to precancerous gastric lesions.

BACKGROUND: The increased odds of stomach cancer among subjects with blood type A have been reported in epidemiological studies. AIM: To study the relation of family history of gastric cancer and ABO blood type with precancerous gastric lesions in a high-risk area for stomach cancer. Subjects and setting We examined 3400 adults aged 35-64 in a population-based gastric endoscopic screening in a county in China with one of the highest rates of stomach cancer in the world. METHODS: In this cross-sectional study, data on family cancer history, ABO blood type and other characteristics of the participants were obtained by interview and blood test. Responses were compared between those with the most advanced gastric lesions, dysplasia (DYS) or intestinal metaplasia (IM), versus those with chronic atrophic gastritis (CAG) or superficial gastritis (SG). RESULTS: The prevalence odds ratio (OR) for blood type A relative to other types was 1.39 (95% CI : 1.12-1.73) for DYS and 1.28 (95% CI : 1.06-1.53) for IM. The OR associated with parental history of stomach cancer was 1.88 (95% CI : 1.20-2.95) for DYS, but the numbers were too small to evaluate aggregation among siblings. The combined OR associated with blood type A and a parental of history of gastric cancer was 2.61 (95% CI : 1.59-4.30) for DYS and 1.46 (95% CI : 0.93-2.31) for IM. CONCLUSIONS: The findings suggest that genetic factors play a role in developing precancerous gastric lesions.

Evolution of precancerous lesions in a rural Chinese population at high risk of gastric cancer.

The pathogenesis of gastric cancer (GC), particularly of the intestinal type, is thought to involve a multistep and multifactorial process. Our objective was to determine the rates of transition from early to advanced gastric lesions in a population in Linqu County, China, where the GC rates are among the highest in the world. An endoscopic screening survey was launched in 1989-1990 among 3,399 residents aged 34-64 years with precancerous lesions diagnosed from biopsies taken from 7 standard locations in the stomach and from any suspicious sites. The cohort was subsequently followed, with endoscopic and histopathologic examinations conducted in 1994. Logistic regression analysis was used to estimate odds ratios (ORs) of progression to advanced lesions of various levels of severity as a function of age, sex and baseline pathology. The rates of progression were higher among older subjects, among men and among subjects with more extensive gastric lesions. 34 incident GCs were identified during the follow-up period. The ORs of GC, adjusted for age and sex, varied from 17.1, for those with baseline diagnoses of superficial intestinal metaplasia (IM), to 29.3, for those with deep IM or mild dysplasia (DYS) or IM with glandular atrophy and neck hyperplasia, to 104.2, for those with moderate or severe DYS, as compared with subjects with superficial gastritis (SG) or chronic atrophic gastritis (CAG) at baseline. Our prospective study of a high-risk population revealed sharp increases in the risk of GC and advanced precursor lesions according to the severity of lesions diagnosed at the start of follow-up. Int. J. Cancer, 83:615-619, 1999. Published 1999 Wiley-Liss, Inc.

Helicobacter pylori infection and mode of transmission in a population at high risk of stomach cancer.

BACKGROUND: Helicobacter pylori (H. pylori) is a recognized cause of chronic gastritis and peptic ulcer disease, and is strongly suspected to play a role in the aetiology of stomach cancer but little is known about the mode of transmission. AIM: To determine the prevalence of H. pylori infection in children and investigate potential modes of transmission in rural China. SUBJECTS AND SETTING: We examined 98 children aged 3-12 years and 289 adults aged 35-64 years in a village in Linqu County, China, which has one of the highest rates of stomach cancer in the world. METHOD: H. pylori infection was determined by 13C-urea breath test in children and by an enzyme-linked immunosorbent assay in adults. RESULTS: Among 98 tested children, 68 (69%) were H. pylori positive, but the prevalence rates varied as a function of age, rising from about 50% at ages 3-4 to 85% at ages 9-10 before falling to 67% at ages 11-12. Boys had a higher infection rate than girls (77.8% versus 59.1%, P < 0.05). Among 289 adults, 195 (68%) were H. pylori positive, with a somewhat higher rate of positivity in younger compared to older age groups. The prevalence of H. pylori infection clustered within families. In families with at least one infected parent, 85% of children were H. pylori positive, while in families with both parents uninfected, only 22% of children were H. pylori positive (odds ratio [OR] = 30.4, 95% CI : 4.0-232). CONCLUSIONS: These findings demonstrate the acquisition of H. pylori infection during early childhood in a population at high risk of stomach cancer, in a manner consistent with a person-to-person mode of transmission between parents and children.

Helicobacter pylori infection, garlic intake and precancerous lesions in a Chinese population at low risk of gastric cancer.

BACKGROUND: Cangshan County of Shandong Province has one of the lowest rates of gastric cancer (GC) in China. While intestinal metaplasia (IM) and dysplasia (DYS) are less common in Cangshan than in areas of Shandong at high risk of GC, these precursor lesions nevertheless affect about 20% of adults age > or = 55. SUBJECTS AND SETTING: In order to evaluate determinants of IM and DYS in Cangshan County, a low risk area of GC a survey was conducted among 214 adults who participated in a gastroscopic screening survey in Cangshan County in 1994. METHOD: A dietary interview and measurement of serum Helicobacter pylori antibodies were performed. RESULTS: The prevalence of H. pylori was lowest (19%) among those with normal gastric mucosa, rising steadily to 35% for superficial gastritis (SG), 56% for chronic atrophic gastritis (CAG), 80% for IM, and 100% for DYS. The prevalence odds of precancerous lesions were compared with the odds of normal histology or SG. The odds ratio (OR) or CAG associated with H. pylori positivity was 4.2 (95% confidence interval [CI] : 1.7-10.0), while the OR of IM/DYS associated with H. pylori positivity was 31.5 (95% CI: 5.2-187). After adjusting for H. pylori infection, drinking alcohol was a risk factor for CAG (OR = 3.2, 95% CI: 1.1-9.2) and IM/DYS (OR = 7.8, 95% CI: 1.3-47.7). On the other hand, consumption of garlic showed non-significant protective effects and an inverse association with H. pylori infection. CONCLUSIONS: The findings of this study suggest that infection with H. pylori is a risk factor and garlic may be protective, in the development and progression of advanced precancerous gastric lesions in an area of China at relatively low risk of GC.

Precancerous lesions in two counties of China with contrasting gastric cancer risk.

BACKGROUND: Gastric cancer (GC) is one of the most common cancers worldwide and shows remarkable geographical variation even within countries such as China. Linqu County in Shandong Province of northeast China has a GC rate that is 15 times higher than that of Cangshan County in Shandong, even though these counties are within 200 miles of each other. METHOD: In order to evaluate the frequency of precancerous gastric lesions in Linqu and Cangshan Counties we examined 3400 adults in Linqu County and 224 adults in Cangshan County. An endoscopic examination with four biopsies was performed in each individual of the two populations. RESULTS: The prevalence of intestinal metaplasia (IM) and dysplasia (DYS) was 30% and 15.1%, respectively, in Linqu compared to 7.9% and 5.6% in Cangshan (P < 0.01). Within these histological categories, advanced grades were found more often in Linqu than in Cangshan. The prevalences of IM and DYS were more common at each biopsy site in Linqu, where the lesions also tended to affect multiple sites. CONCLUSIONS: The findings of this study support the concept that IM and DYS are closely correlated with risks of GC and represent late stages in the multistep process of gastric carcinogenesis.

Familial predisposition to precancerous gastric lesions in a high-risk area of China.

Aggregation of intestinal metaplasia and dysplasia was investigated among families participating in a population-based gastroscopic screening survey in an area of China with one of the world's highest rates of stomach cancer. The prevalence of gastric dysplasia was significantly increased among those with dysplasia among siblings or spouses, but not parents. The odds of dysplasia were nearly doubled if an eldest brother or a spouse was affected. Sibling and spousal associations for intestinal metaplasia were much less pronounced and not statistically significant. The specificity of the findings suggests that familial risk of advanced precancerous lesions (dysplasia) is influenced not only by genetic factors, but also by environmental factors operating in childhood and early adult life.

Mortality differentials by marital status: an international comparison.

Although the greater longevity of married people as compared with unmarried persons has been demonstrated repeatedly, there have been very few studies of a comparative nature. We use log-linear rate models to analyze marital-status-specific death rates for a large number of developed countries. The results indicate that divorced persons, especially divorced men, have the highest death rates among the unmarried groups of the respective genders; the excess mortality of unmarried persons relative to the married has been generally increasing over the past two to three decades; and divorced and widowed persons in their twenties and thirties have particularly high risks of dying, relative to married persons of the same age. In addition, the analysis suggests that a selection process is operating with regard to single and divorced persons: the smaller the proportion of persons who never marry or who are divorced, the higher the resulting death rates.