Genetic architecture of alcohol consumption identified by a genotype-stratified GWAS and impact on esophageal cancer risk in Japanese people

An East Asian-specific variant on aldehyde dehydrogenase 2 (ALDH2 rs671, G>A) is the major genetic determinant of alcohol consumption. We performed an rs671 genotype-stratified genome-wide association study meta-analysis of alcohol consumption in 175,672 Japanese individuals to explore gene-gene interactions with rs671 behind drinking behavior. The analysis identified three genome-wide significant loci (GCKR, KLB, and ADH1B) in wild-type homozygotes and six (GCKR, ADH1B, ALDH1B1, ALDH1A1, ALDH2, and GOT2) in heterozygotes, with five showing genome-wide significant interaction with rs671. Genetic correlation analyses revealed ancestry-specific genetic architecture in heterozygotes. Of the discovered loci, four (GCKR, ADH1B, ALDH1A1, and ALDH2) were suggested to interact with rs671 in the risk of esophageal cancer, a representative alcohol-related disease. Our results identify the genotype-specific genetic architecture of alcohol consumption and reveal its potential impact on alcohol-related disease risk.

A Century of Change: Unraveling the Impact of Socioeconomic/Historical Milestones on Age at Menarche and Other Female Reproductive Factors in Japan

BACKGROUND

Reproductive factors such as age at menarche are known to be associated with disease risk, but data on trends in these factors in Japan are limited. In this study, we investigated secular trends in reproductive factors and explored their potential association with socioeconomic and historical events.

METHODS

We conducted a retrospective analysis of 62,005 Japanese women born between 1890 and 1991 using a survey conducted over 25 years. Trends in reproductive factors were analyzed using linear and joinpoint regression models, and their associations with major historical events involving Japan were evaluated.

RESULTS

We found that the age at menarche showed a significant downward trend (P-value<0.001) over the century. Three joinpoints were identified, in 1932 (15.23 years old), 1946 (13.48 years old), and 1959 (12.71 years old), which indicated that average age at menarche decreased by approximately 0.8% per year between 1932 and 1946, and then by 0.4% per year between 1946 and 1959, both of which were statistically significant. However, after 1959, age of menarche remained stable. Analyses of other reproductive factors found significant changes, including a decrease in parity and the number of babies breastfed, and an increase in age at first birth.

CONCLUSION

Age at menarche showed a long-term downward trend in Japan, with significant change points in annual percent change. Other factors showed secular changes in trends as well. These change points were observed at the same time as historical events, namely wars and economic development, suggesting that socioeconomic and environmental changes at the population level affect reproductive factors in females.

Mediation analysis unveils a carcinogenic effect of ADH1B rs1229984 through mechanisms other than change in drinking intensity: oesophageal cancer case-control study

BACKGROUND

Ingested alcohol is predominantly oxidized to acetaldehyde by alcohol dehydrogenase 1B (ADH1B), and acetaldehyde is further oxidized to acetate mainly by aldehyde dehydrogenase 2 (ALDH2). Although alcohol consumption is a convincing risk factor for oesophageal cancer, the role of ADH1B rs1229984 (His48Arg), the single-nucleotide polymorphism associated with slow alcohol metabolism, in oesophageal cancer development is unclear. Because this single-nucleotide polymorphism is associated with both increased risk of oesophageal cancer and drinking intensity, its association with oesophageal cancer might operate either through a direct pathway independently of drinking intensity, via an indirect pathway mediated by drinking intensity, or both.

METHODS

To disentangle these different pathways, we applied a mediation analysis to an oesophageal cancer case-control study (600 cases and 865 controls) by defining the ADH1B Arg allele and alcohol consumption as exposure and mediator, respectively, and decomposed the total-effect odds ratio of the ADH1B Arg allele into direct- and indirect-effect odds ratio.

RESULTS

The ADH1B Arg allele was associated with oesophageal cancer risk through pathways other than change in drinking intensity (direct-effect odds ratio, 2.03; 95% confidence interval, 1.41-2.92), in addition to the indirect pathway mediated by drinking intensity (indirect-effect odds ratio, 1.27; 95% confidence interval, 1.05-1.53). Further analyses by stratifying genotypes of ALDH2 rs671 (Glu504Lys), the functional single-nucleotide polymorphism that strongly attenuates the enzymatic activity, showed significant direct-effect odds ratio within each stratum.

CONCLUSIONS

These results indicate that ADH1B Arg allele contributes to oesophageal cancer risk by slowing alcohol breakdown, in addition to its effect on the amount of alcohol consumed.

Helicobacter pylori, Homologous-Recombination Genes, and Gastric Cancer

BACKGROUND

Helicobacter pylori infection is a well-known risk factor for gastric cancer. However, the contribution of germline pathogenic variants in cancer-predisposing genes and their effect, when combined with H. pylori infection, on the risk of gastric cancer has not been widely evaluated.

METHODS

We evaluated the association between germline pathogenic variants in 27 cancer-predisposing genes and the risk of gastric cancer in a sample of 10,426 patients with gastric cancer and 38,153 controls from BioBank Japan. We also assessed the combined effect of pathogenic variants and H. pylori infection status on the risk of gastric cancer and calculated the cumulative risk in 1433 patients with gastric cancer and 5997 controls from the Hospital-based Epidemiologic Research Program at Aichi Cancer Center (HERPACC).

RESULTS

Germline pathogenic variants in nine genes (APC, ATM, BRCA1, BRCA2, CDH1, MLH1, MSH2, MSH6, and PALB2) were associated with the risk of gastric cancer. We found an interaction between H. pylori infection and pathogenic variants in homologous-recombination genes with respect to the risk of gastric cancer in the sample from HERPACC (relative excess risk due to the interaction, 16.01; 95% confidence interval [CI], 2.22 to 29.81; P = 0.02). At 85 years of age, persons with H. pylori infection and a pathogenic variant had a higher cumulative risk of gastric cancer than noncarriers infected with H. pylori (45.5% [95% CI, 20.7 to 62.6] vs. 14.4% [95% CI, 12.2 to 16.6]).

CONCLUSIONS

H. pylori infection modified the risk of gastric cancer associated with germline pathogenic variants in homologous-recombination genes. (Funded by the Japan Agency for Medical Research and Development and others.).

Blood Lipids and the Risk of Colorectal Cancer: Mendelian Randomization Analyses in the Japanese Consortium of Genetic Epidemiology Studies

The associations between blood lipids, including total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), triglycerides, and low-density lipoprotein cholesterol (LDL-C), and colorectal cancer risk are controversial. We evaluated potential causal relationships between blood lipids and colorectal cancer risk. Using the baseline data from the Japanese Consortium of Genetic Epidemiology studies, we estimated the single-nucleotide polymorphism (SNP)-exposure associations (n = 34,546 for TC, n = 50,290 for HDL-C, n = 51,307 for triglycerides, and n = 30,305 for LDL-C). We also estimated the SNP-outcome associations in another Japanese dataset (n = 7,936 colorectal cancer cases and n = 38,042 controls). We conducted Mendelian randomization (MR) analyses for the association between each blood lipid type and the risk of colorectal cancer using an inverse variance-weighted method. The total variances explained by the selected SNPs in TC (68 SNPs), HDL-C (50 SNPs), log-transformed triglycerides (26 SNPs), and LDL-C (35 SNPs) were 7.0%, 10.0%, 6.2%, and 5.7%, respectively. The odds ratios for colorectal cancer were 1.15 [95% confidence interval (CI), 1.01-1.32] per 1 standard deviation (SD; 33.3 mg/dL) increase in TC, 1.11 (95% CI, 0.98-1.26) per 1 SD (15.4 mg/dL) increase in HDL-C, 1.06 (95% CI, 0.90-1.26) per 1 SD (0.5 log-mg/dL) increase in log-transformed triglycerides, and 1.17 (95% CI, 0.91-1.50) per 1 SD (29.6 mg/dL) increase in LDL-C. Sensitivity analyses consistently suggested the positive association between TC and colorectal cancer, whereas results of each lipid component were inconsistent. In conclusion, this large MR study of a Japanese population showed a potentially causal association between high TC and colorectal cancer risk, although the association between each lipid component and colorectal cancer remained inconclusive.

PREVENTION RELEVANCE

In this large MR analysis of a Japanese population, a positive association was found between genetically predicted high total cholesterol (TC) levels and an increased risk of colorectal cancer. Therefore, lowering TC levels by lifestyle modifications or medications may be justified for the purpose of preventing colorectal cancer.

Circulating immune- and inflammation-related biomarkers and early-stage noncardia gastric cancer risk

BACKGROUND

In Helicobacter pylori-driven gastric cancer, mucosal colonization induces chronic inflammation that may variably progress to cancer. Prospective studies of circulating inflammation-related proteins have suggested weak associations with gastric cancer risk. To assess potential utility as a screening tool in clinical settings, we examined circulating levels of a wide range of key inflammation molecules for associations with early-stage gastric cancer.

METHODS

We used pretreatment EDTA plasma from 239 individuals with early-stage noncardia gastric cancer (203 stage I and 36 stage II) and 256 age-frequency-matched H. pylori-seropositive cancer-free controls within the Hospital-based Epidemiologic Research Program at Aichi Cancer Center. Levels of 92 biomarkers were measured by proximity extension assays using Olink's Proseek Immuno-oncology Panel. Odds ratios (ORs) for association with gastric cancer risk were calculated for quantiles (two to four categories) of each biomarker from unconditional logistic regression models, adjusted for age, sex, smoking and alcohol consumption. Two-sided P values <0.05 were considered as significant. The false discovery rate (FDR) was used to correct for multiple comparisons.

RESULTS

Of 83 evaluable biomarkers, lower levels of TNFRSF12A (per quartile OR, 0.82; nominal P-trend = 0.02) and ADGRG1 (per quartile OR, 0.84; nominal P-trend = 0.03) were associated with early-stage gastric cancer but were not statistically significant after FDR correction.

CONCLUSION

Our study did not identify any inflammation-related biomarkers that may be useful for early disease detection. To date, this is the first assessment of circulating inflammation-related proteins in early-stage gastric cancer. Given the complex inflammation processes preceding malignant transformation, further investigation of other biomarkers is warranted.

Impact of socioeconomic status and sibling number on the prevalence of Helicobacter pylori infection: a cross-sectional study in a Japanese population

Helicobacter pylori infection is a significant risk factor for gastric cancer. The infection is acquired mainly in early childhood and is influenced by environmental factors, including socioeconomic status and sibling number. However, the impact of socioeconomic status and sibling number on Helicobacter pylori infection has not been well studied in Japan. We conducted a cross-sectional study to evaluate the impact of socioeconomic status, represented by education level, and sibling number on the prevalence of Helicobacter pylori infection among 3,423 non-cancer subjects who visited Aichi Cancer Center between 2005 and 2013. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) using a logistic regression model adjusted for potential confounding variables. Of the 3,423 subjects, 1,459 (42.6%) were Helicobacter pylori-positive. The prevalence of Helicobacter pylori infection linearly decreased with increasing socioeconomic status [ORs (95% CIs) of moderate and high socioeconomic status relative to low socioeconomic status of 0.67 (0.53-0.84) and 0.43 (0.34-0.54), respectively; P trend=9.7×10^-17]. In contrast, the prevalence of Helicobacter pylori infection linearly increased with increasing sibling number [ORs (95% CIs) of SN 3-4 and ≥5 relative to sibling number ≤2 of 1.74 (1.47-2.06) and 2.54 (2.12-3.04), respectively; P trend=1.2×10^-24]. This study showed that socioeconomic status and sibling number were significantly associated with the prevalence of Helicobacter pylori infection.

Association between germline pathogenic variants and breast cancer risk in Japanese women: the HERPACC study

Approximately 5-10% of breast cancers are hereditary, caused by germline pathogenic variants (GPVs) in breast cancer predisposition genes. To date, most studies of the prevalence of GPVs and risk of breast cancer for each gene based on cases and non-cancer controls have been conducted in Europe and the United States, and little information from Japanese populations is available. Furthermore, no studies considered confounding by established environmental factors and single nucleotide polymorphisms (SNPs) identified in genome-wide association studies (GWAS) together in GPV evaluation. To evaluate the association between GPVs in nine established breast cancer predisposition genes including BRCA1/2 and breast cancer risk in Japanese women comprehensively, we conducted a case-control study within the Hospital-based Epidemiologic Research Program at Aichi Cancer Center (629 cases and 1153 controls). The associations between GPVs and the risk of breast cancer were assessed by odds ratios (OR) and 95% confidence intervals (CI) using logistic regression models adjusted for potential confounders. A total of 25 GPVs were detected among all cases (4.0%: 95%CI:2.6-5.9), whereas four individuals carried GPVs in all controls (0.4%). OR for breast cancer by all GPVs and by GPVs in BRCA1/2 was 12.2 (4.4-34.0, P = 1.74E-06) and 16.0 (4.2-60.9, P = 5.03E-0.5), respectively. A potential confounding with GPVs was observed for the GWAS-identified SNPs, whereas not for established environmental risk factors. In conclusion, GPVs increase the risk of breast cancer in Japanese women regardless of environmental factors and GWAS-identified SNPs. Future studies investigating interactions with environment and SNPs are warranted.

New insights into the genetic contribution of ALDH2 rs671 in pancreatic carcinogenesis: evaluation by mediation analysis

A functional variant on ALDH2 rs671 (G>A) confers a protective effect against alcohol‐induced carcinogenesis through an indirect pathway mediated by decreased alcohol consumption. Conversely, this variant also contributes to the accumulation of carcinogenic agents, resulting in a direct carcinogenic effect. This study aimed to separately quantify these two opposing effects of the rs671 A allele on pancreatic cancer risk and explore the impact of the rs671 A allele and alcohol consumption on pancreatic carcinogenesis. We included 426 cases and 1456 age‐ and sex‐matched controls. Odds ratio (OR) and 95% confidence interval (CI) for alcohol consumption were estimated using a conditional logistic regression model. By defining rs671 A allele and alcohol consumption as exposure and mediator, respectively, we used mediation analysis to decompose the total‐effect OR of the rs671 A allele into direct‐ and indirect‐effect ORs. Alcohol consumption (10 g/d) was associated with pancreatic cancer risk (OR, 1.05; 95% CI, 1.01‐1.10), but tests for interaction between the rs671 A allele and alcohol consumption were nonsignificant, indicating that the effect of alcohol consumption did not vary by genotype. Mediation analysis showed that the nonsignificant total effect (OR, 1.15; 95% CI, 0.92‐1.44) can be decomposed into the carcinogenic direct (OR, 1.34; 95% CI, 1.04‐1.72) and protective indirect effect (OR, 0.86; 95% CI, 0.77‐0.95). This study supports the association between alcohol consumption and pancreatic cancer risk and indicates the potential contribution of the rs671 A allele to pancreatic carcinogenesis through impaired metabolism of known or unknown ALDH2 substrates.

Associations of circulating mediators of inflammation, cell regulation and immune response with esophageal squamous cell carcinoma

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is the most common histologic subtype of esophageal cancer globally. The development of squamous cell carcinoma has important inflammatory influences and effects. We, therefore, examined circulating levels of inflammation- and immune-related proteins for associations with ESCC.

METHODS

We used pre-treatment EDTA plasma from 80 ESCC patients (44% clinical stages I and II) and 80 cancer-free control individuals within the Hospital-based Epidemiologic Research Program at Aichi Cancer Center. Levels of 184 biomarkers were measured by high-throughput multiplexed proximity extension assays using Olink's Proseek Cell Regulation and Immuno-Oncology Panels. ESCC odds ratios (OR) per quantile (based on two to four categories) of each biomarker were calculated by unconditional logistic regression models, adjusted for age, sex, cigarette smoking and alcohol consumption. Correlations among continuous biomarker levels were assessed by Spearman's rank correlation. All statistical tests were two-sided with p values < 0.05 considered as significant. Given the exploratory nature of the study, we did not adjust for multiple comparisons.

RESULTS

Seven proteins were undetectable in nearly all samples. Of the remaining 177 evaluable biomarkers, levels of cluster of differentiation 40 (CD40, per quartile OR 1.64; p trend = 0.018), syntaxin 16 (STX16, per quartile OR 1.63; p trend = 0.008), heme oxygenase 1 (per quartile OR 1.59; p trend = 0.014), and γ-secretase activating protein (GSAP, per quartile OR 1.47; p trend = 0.036) were significantly associated with ESCC. Amongst these significant markers, levels of CD40, STX16, and GSPA were moderately correlated (Rho coefficients 0.46-0.55; p < 0.05).

CONCLUSION

Our case-control study expands the range of inflammation and immune molecules associated with ESCC. These novel findings warrant replication and functional characterization.

Body mass index and colorectal cancer risk: A Mendelian randomization study

Traditional observational studies have reported a positive association between higher body mass index (BMI) and the risk of colorectal cancer (CRC). However, evidence from other approaches to pursue the causal relationship between BMI and CRC is sparse. A two-sample Mendelian randomization (MR) study was undertaken using 68 single nucleotide polymorphisms (SNPs) from the Japanese genome-wide association study (GWAS) and 654 SNPs from the GWAS catalogue for BMI as sets of instrumental variables. For the analysis of SNP-BMI associations, we undertook a meta-analysis with 36 303 participants in the Japanese Consortium of Genetic Epidemiology studies (J-CGE), comprising normal populations. For the analysis of SNP-CRC associations, we utilized 7636 CRC cases and 37 141 controls from five studies in Japan, and undertook a meta-analysis. Mendelian randomization analysis of inverse-variance weighted method indicated that a one-unit (kg/m2 ) increase in genetically predicted BMI was associated with an odds ratio of 1.13 (95% confidence interval, 1.06-1.20; P value <.001) for CRC using the set of 68 SNPs, and an odds ratio of 1.07 (1.03-1.11, 0.001) for CRC using the set of 654 SNPs. Sensitivity analyses robustly showed increased odds ratios for CRC for every one-unit increase in genetically predicted BMI. Our MR analyses strongly support the evidence that higher BMI influences the risk of CRC. Although Asians are generally leaner than Europeans and North Americans, avoiding higher BMI seems to be important for the prevention of CRC in Asian populations.

Differential Effect of Polymorphisms on Body Mass Index Across the Life Course of Japanese: The Japan Multi-Institutional Collaborative Cohort Study

BACKGROUND

Obesity is a reported risk factor for various health problems. Genome-wide association studies (GWASs) have identified numerous independent loci associated with body mass index (BMI). However, most of these have been focused on Europeans, and little evidence is available on the genetic effects across the life course of other ethnicities.

METHODS

We conducted a cross-sectional study to examine the associations of 282 GWAS-identified single nucleotide polymorphisms with three BMI-related traits, current BMI, BMI at 20 years old (BMI at 20), and change in BMI (BMI change), among 11,586 Japanese individuals enrolled in the Japan Multi-Institutional Collaborative Cohort study. Associations were examined using multivariable linear regression models.

RESULTS

We found a significant association (P < 0.05/282 = 1.77 × 10-4) between BMI and 11 polymorphisms in or near FTO, BDNF, TMEM18, HS6ST3, and BORCS7. The trend was similar between current BMI and BMI change, but differed from that of the BMI at 20. Among the significant variants, those on FTO were associated with all BMI traits, whereas those on TMEM18 and HS6SR3 were only associated with BMI at 20. The association of FTO loci with BMI remained, even after additional adjustment for dietary energy intake.

CONCLUSIONS

Previously reported BMI-associated loci discovered in Europeans were also identified in the Japanese population. Additionally, our results suggest that the effects of each loci on BMI may vary across the life course and that this variation may be caused by the differential effects of individual genes on BMI via different pathways.

Digenic mutations in ALDH2 and ADH5 impair formaldehyde clearance and cause a multisystem disorder, AMeD syndrome

Rs671 in the aldehyde dehydrogenase 2 gene (ALDH2) is the cause of Asian alcohol flushing response after drinking. ALDH2 detoxifies endogenous aldehydes, which are the major source of DNA damage repaired by the Fanconi anemia pathway. Here, we show that the rs671 defective allele in combination with mutations in the alcohol dehydrogenase 5 gene, which encodes formaldehyde dehydrogenase (ADH5^FDH ), causes a previously unidentified disorder, AMeD (aplastic anemia, mental retardation, and dwarfism) syndrome. Cellular studies revealed that a decrease in the formaldehyde tolerance underlies a loss of differentiation and proliferation capacity of hematopoietic stem cells. Moreover, Adh5^-/-Aldh2 ^E506K/E506K double-deficient mice recapitulated key clinical features of AMeDS, showing short life span, dwarfism, and hematopoietic failure. Collectively, our results suggest that the combined deficiency of formaldehyde clearance mechanisms leads to the complex clinical features due to overload of formaldehyde-induced DNA damage, thereby saturation of DNA repair processes.

Abstract 3486: Body mass index and colorectal cancer risk in Japanese populations: a Mendelian randomization study

Background: Prospective cohort studies have shown a positive association between body mass index (BMI) and the risk of colorectal cancer (CRC). However, limitations inherent in traditional observational studies, such as reverse causality and residual confounding, might explain the association. To overcome these limitations, Mendelian randomization (MR) studies of the BMI-CRC association have been conducted in European and U.S. groups, but the association remains to be clarified in East Asians. Purpose: We performed MR analyses to investigate the causal association between BMI and CRC in Japanese populations.

Methods: Our study design consisted of 4 steps. (1) Based on a previous Genome-Wide Association Study in Japanese populations, we selected 68 BMI-associated single nucleotide polymorphisms (SNPs), which explained about 2.0% of the BMI variance, as instruments. (2) We examined the associations between 68 SNPs and BMI among general Japanese populations in the Japanese Consortium of Genetic Epidemiology studies (N=36,253). (3) We performed a fixed-effect meta-analysis to investigate associations between 68 SNPs and CRC using individual-level data and publicly available summary-statistic data of Japanese populations (cases=7,473, controls=33,322). (4) Finally, we used the inverse-variance weighted (IVW) method to calculate MR estimates. Several sensitivity analyses were applied to assess robustness or horizontal pleiotropy using weighted median, weighted mode, MR-Egger regression, and MR-Pleiotropy Residual Sum and Outlier (PRESSO) methods.

Results: In the main analysis using the IVW method, a one-unit increase in BMI was associated with an odds ratio of 1.12 (95% confidence interval [CI]: 1.06-1.20) for CRC. Sensitivity analyses consistently showed increased odds ratios for CRC per one-unit increase in BMI. The odds ratios for weighted median, weighted mode, and MR-Egger regression were 1.16 (95% CI: 1.06-1.27), 1.14 (95% CI: 1.05-1.24), and 1.10(95% CI: 0.98-1.23), respectively. The MR-Egger intercept P-value was 0.63. No outlier was detected using the MR-PRESSO method.

Conclusions: Our MR analyses provide evidence that BMI is positively associated with CRC in Japanese populations. Our findings seem to suggest that MR estimates for the BMI-CRC association may be consistent across different ethnicities.

Citation Format: Shiori Suzuki, Atsushi Goto, Masahiro Nakatochi, Akira Narita, Taiki Yamaji, Norie Sawada, Ryoko Katagiri, Tsuyoshi Hachiya, Yoichi Sutoh, Isao Oze, Yuriko Koyanagi, Yumiko Kasugai, Hidemi Ito, Hiroaki Ikezaki, Keitaro Tanaka, Takashi Tamura, Haruo Mikami, Toshiro Takezaki, Sadao Suzuki, Nagato Kuriyama, Kiyonori Kuriki, Yoshikuni Kita, Kokichi Arisawa, Kenji Takeuchi, Kozo Tanno, Atsushi Shimizu, Gen Tamiya, Atsushi Hozawa, Kengo Kinoshita, Kenji Wakai, Makoto Sasaki, Masayuki Yamamoto, Keitaro Matsuo, Shoichiro Tsugane, Motoki Iwasaki. Body mass index and colorectal cancer risk in Japanese populations: a Mendelian randomization study [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3486.

Genome-wide association meta-analysis identifies GP2 gene risk variants for pancreatic cancer

Pancreatic cancer is the fourth leading cause of cancer-related deaths in Japan. To identify risk loci, we perform a meta-analysis of three genome-wide association studies comprising 2,039 pancreatic cancer patients and 32,592 controls in the Japanese population. Here, we identify 3 (13q12.2, 13q22.1, and 16p12.3) genome-wide significant loci (P < 5.0 × 10⁻⁸), of which 16p12.3 has not been reported in the Western population. The lead single nucleotide polymorphism (SNP) at 16p12.3 is rs78193826 (odds ratio = 1.46, 95% confidence interval = 1.29-1.66, P = 4.28 × 10⁻⁹), an Asian-specific, nonsynonymous glycoprotein 2 (GP2) gene variant. Associations between selected GP2 gene variants and pancreatic cancer are replicated in 10,822 additional cases and controls of East Asian origin. Functional analyses using cell lines provide supporting evidence of the effect of rs78193826 on KRAS activity. These findings suggest that GP2 gene variants are probably associated with pancreatic cancer susceptibility in populations of East Asian ancestry.

Previous genome-wide association studies have identified risk loci for pancreatic cancer but were centered on individuals of European ancestry. Here the authors identify GP2 gene variants associated with pancreatic cancer susceptibility in populations of East Asian ancestry.

Across-Site Differences in the Mechanism of Alcohol-Induced Digestive Tract Carcinogenesis: An Evaluation by Mediation Analysis

A genetic variant on aldehyde dehydrogenase 2 (ALDH2 rs671, Glu504Lys) contributes to carcinogenesis after alcohol consumption. Somewhat conversely, the ALDH2 Lys allele also confers a protective effect against alcohol-induced carcinogenesis by decreasing alcohol consumption due to acetaldehyde-related adverse effects. Here, we applied a mediation analysis to five case-control studies for head and neck, esophageal, stomach, small intestine, and colorectal cancers, with 4,099 cases and 6,065 controls, and explored the potentially heterogeneous impact of alcohol drinking on digestive tract carcinogenesis by decomposing the total effect of the ALDH2 Lys allele on digestive tract cancer risk into the two opposing effects of the carcinogenic effect (direct effect) and the protective effect (indirect effect mediated by drinking behavior). Alcohol was associated with an increased risk of most digestive tract cancers, but significant direct effects were observed only for upper gastrointestinal tract cancer risk, and varied substantially by site, with ORs (95% confidence interval) of 1.83 (1.43-2.36) for head and neck cancer, 21.15 (9.11-49.12) for esophageal cancer, and 1.65 (1.38-1.96) for stomach cancer. In contrast, a significant protective indirect effect was observed on risk for all cancers, except small intestine cancer. These findings suggest that alcohol is a major risk factor for digestive tract cancers, but its impact as a surrogate for acetaldehyde exposure appears heterogeneous by site. Meanwhile, the behavior-related effect of the ALDH2 Lys allele results in a decreased risk of most digestive tract cancers. SIGNIFICANCE: These findings support that genetic alcohol avoidance is a factor against alcohol-induced cancers.

Helicobacter pylori (HP) infection alone, but not HP-induced atrophic gastritis, increases the risk of gastric lymphoma: a case-control study in Japan

Infection with Helicobacter pylori (H. pylori) is associated with an increased risk of gastric malignant lymphoma. The chronic inflammation of gastric mucosa by H. pylori infection induces lymphomagenesis. Although this chronic mucosal inflammation also results in atrophic gastritis, evidence supporting the possible significance of atrophic gastritis in gastric lymphomagenesis is scarce. Here, to evaluate the association between gastric mucosal atrophy and the risk of gastric lymphoma, we conducted a matched case-control study at Aichi Cancer Center focusing on the attribution of H. pylori infection status and pepsinogen (PG) serum levels. In total, 86 patients with gastric lymphoma (including 49 cases of extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) and 24 cases of diffuse large B cell lymphoma (DLBCL)) and 1720 non-cancer controls were included. Odds ratios (ORs) and 95% confidence intervals (CIs) were assessed by conditional logistic regression analysis with adjustment for potential confounders. Results failed to show a statistically significant association between atrophic gastritis and the risk of gastric lymphoma. The adjusted ORs of positive atrophic gastritis relative to negative for overall gastric lymphoma, MALT lymphoma, DLBCL, and other lymphomas were 0.77 (95% CI 0.45-1.33), 0.65 (0.30-1.39), 1.03 (0.38-2.79), and 0.84 (0.22-3.29), respectively. In contrast, a positive association between overall gastric lymphoma and H. pylori infection was observed (OR = 2.14, 95% CI 1.30-3.54). A consistent association was observed for MALT lymphoma, DLBCL, and other lymphomas with ORs of 1.96 (1.00-3.86), 1.92 (0.74-4.95), and 5.80 (1.12-30.12), respectively. These findings suggest that H. pylori infection triggers gastric lymphoma but that epithelial changes due to atrophic gastritis do not inherently affect the development of gastric lymphoma.

Modeling mesothelioma utilizing human mesothelial cells reveals involvement of phospholipase-C beta 4 in YAP-active mesothelioma cell proliferation

Mesotheliomas are frequently characterized by disruption of Hippo pathway due to deletion and/or mutation in genes, such as neurofibromin 2 ( NF2 ). Hippo disruption attenuates yes-associated protein (YAP) phosphorylation allowing YAP to translocate to the nucleus and regulate gene expression. The role of disrupted Hippo pathway in maintenance of established mesotheliomas has been extensively investigated using cell lines; however, its involvement in development of human mesothelioma has not been explored much. Here, we employed immortalized human mesothelial cells to disrupt Hippo pathway. YAP phosphorylation was reduced on NF2 knockdown and the cells exhibited altered growth in vitro , developing tumors when transplanted into nude mice. Similar results were obtained from enforced expression of wild-type or constitutively active (S127A) YAP, indicating the crucial role of activated YAP in the transformation of mesothelial cells. Gene expression analysis comparing control- and YAP-transduced immortalized human mesothelial cells revealed phospholipase-C beta 4 ( PLCB4 ) to be among the genes highly upregulated by YAP. PLCB4 was upregulated by YAP in immortalized human mesothelial cells and downregulated on YAP knockdown in Hippo-disrupted mesothelioma cell lines. PLCB4 knockdown attenuated the growth of YAP-transduced immortalized mesothelial cells and YAP-active, but not YAP-nonactive, mesothelioma cell lines. Our model system thus provides a versatile tool to investigate the mechanisms underlying mesothelioma development. We suggest that PLCB4 may be an attractive drug target for the treatment of mesothelioma.

New mouse model of acute adult T-cell leukemia generated by transplantation of AKT, BCLxL, and HBZ-transduced T cells

Adult T‐cell leukemia/lymphoma (ATL) develops in human T‐cell leukemia virus type 1 (HTLV‐1) carriers. Although the HTLV‐1‐encoded HBZ gene is critically involved, HBZ alone is insufficient and additional, cooperative “hits” are required for the development of ATL. Candidate cooperative hits are being defined, but methods to rapidly explore their roles in ATL development in collaboration with HBZ are lacking. Here, we present a new mouse model of acute type ATL that can be generated rapidly by transplanting in vitro‐induced T cells that have been retrovirally transduced with HBZ and two cooperative genes, BCLxL and AKT, into mice. Co‐transduction of HBZ and BCLxL/AKT allowed these T cells to grow in vitro in the absence of cytokines (Flt3‐ligand and interleukin‐7), which did not occur with any two‐gene combination. Although transplanted T cells were a mixture of cells transduced with different combinations of the genes, tumors that developed in mice were composed of HBZ/BCLxL/AKT triply transduced T cells, showing the synergistic effect of the three genes. The genetic/epigenetic landscape of ATL has only recently been elucidated, and the roles of additional “hits” in ATL pathogenesis remain to be explored. Our model provides a versatile tool to examine the roles of these hits, in collaboration with HBZ, in the development of acute ATL.

Two distinct pools of large-conductance calcium-activated potassium channels in the somatic plasma membrane of central principal neurons

Although nerve cell membranes are often assumed to be uniform with respect to electrical properties, there is increasing evidence for compartmentalization into subdomains with heterogeneous impacts on the overall cell function. Such microdomains are characterized by specific sets of proteins determining their functional properties. Recently, clustering of large-conductance calcium-activated potassium (BK_Ca) channels was shown at sites of subsurface membrane cisterns in cerebellar Purkinje cells (PC), where they likely participate in building a subcellular signaling unit, the 'PLasmERosome'. By applying SDS-digested freeze-fracture replica labeling (SDS-FRL) and postembedding immunogold electron microscopy, we have now studied the spatial organization of somatic BK_Ca channels in neocortical layer 5 pyramidal neurons, principal neurons of the central and basolateral amygdaloid nuclei, hippocampal pyramidal neurons and dentate gyrus (DG) granule cells to establish whether there is a common organizational principle in the distribution of BK_Ca channels in central principal neurons. In all cell types analyzed, somatic BK_Ca channels were found to be non-homogenously distributed in the plasma membrane, forming two pools of channels with one pool consisting of clustered channels and the other of scattered channels in the extrasynaptic membrane. Quantitative analysis by means of SDS-FRL revealed that about two-thirds of BK_Ca channels belong to the scattered pool and about one-third to the clustered pool in principal cell somata. Overall densities of channels in both pools differed in the different cell types analyzed, although being considerably lower compared to cerebellar PC. Postembedding immunogold labeling revealed association of clustered channels with subsurface membrane cisterns and confirmed extrasynaptic localization of scattered channels. This study indicates a common organizational principle for somatic BK_Ca channels in central principal neurons with the formation of a clustered and a scattered pool of channels, and a cell-type specific density of this channel type.

Genetic abnormalities involved in t(12;21) TEL?AML1 acute lymphoblastic leukemia: Analysis by means of array-based comparative genomic hybridization

The TEL (ETV6)-AML1 (RUNX1) chimeric gene fusion is the most common genetic abnormality in childhood acute lymphoblastic leukemias. Evidence suggests that this chimeric gene fusion constitutes an initiating mutation that is necessary but insufficient for the development of leukemia. In a search for additional genetic events that could be linked to the development of leukemia, we applied a genome-wide array-comparative genomic hybridization technique to 24 TEL-AML1 leukemia samples and two cell lines. It was found that at least two chromosomal imbalances were involved in all samples. Recurrent regions of chromosomal imbalance (>10% of cases) and representative involved genes were gain of chromosomes 10 (17%) and 21q (25%; RUNX1) and loss of 12p13.2 (87%; TEL), 9p21.3 (29%; p16INK4a/ARF), 9p13.2 (25%; PAX5), 12q21.3 (25%; BTG1), 3p21 (21%; LIMD1), 6q21 (17%; AIM1 and BLIMP1), 4q31.23 (17%; NR3C2), 11q22-q23 (13%; ATM) and 19q13.11-q13.12 (13%; PDCD5). Enforced expression of TEL and to a lesser extent BTG1, both single genes known to be located in their respective minimum common region of loss, inhibited proliferation of the TEL-AML1 cell line Reh. Together, these findings suggest that some of the genes identified as lost by array-comparative genomic hybridization may partly account for the development of leukemia.

Characterization of target genes at the 2p15-16 amplicon in diffuse large B-cell lymphoma

Amplification of 2p has been observed as a recurrent alteration in diffuse large B-cell lymphoma (DLBCL). Whereas two candidate oncogenes, REL and BCL11A, have been investigated as targets for 2p amplification, the question remains as to whether the true target gene in the amplicon is REL, BCL11A or both. We previously identified frequent genomic gains of chromosomal 2p in 25 out of 99 DLBCL cases by means of genome-wide array comparative genomic hybridization (CGH). All of these 25 cases included recurrent copy number gain at 2p15-16. In the study presented here, cases were analyzed in greater detail by means of contig bacterial artificial chromosome (BAC) array CGH for the 4.5-Mb region at 2p15-16, which contained 33 BAC clones. We confined the minimal common region to 500-kb in length, where only the candidate oncogene REL, and not BCL11A, is located. Real-time quantitative PCR was carried out to investigate the correlation between genomic gain and expression. It showed a significant correlation for both genes, indicating that these two genes are common targets for the 2p15-16 amplicon. However, given the fact that REL is more frequently amplified than BCL11A, the REL gene may play a more important role than BCL11A in the pathogenesis of DLBCL.

Identification ofCCND3andBYSLas Candidate Targets for the 6p21 Amplification in Diffuse Large B-Cell Lymphoma

PURPOSE

Increases in gene dosage through DNA amplification represents a common feature of many tumors and can result in the up-regulation of tumor-promoting genes. Our recent genome-wide, array-based comparative genomic hybridization analysis of 66 cases of diffuse large B-cell lymphoma found that genomic gain of 6p21 was observed in as many as 17 cases, including 14 cases with low-level copy number gain and three cases with high-level copy number gains (amplifications).

EXPERIMENTAL DESIGN AND RESULTS

To identify the target gene(s) for 6p21 amplification, we constructed a detailed amplicon map at the region of genomic amplification with the aid of high-resolution contig array-based comparative genomic hybridization glass slides, consisting of contiguously ordered bacterial artificial chromosome/P1-derived artificial chromosome clones covering 3 Mb throughout the 6p21 amplification region. Alignment of the amplifications identified a minimally overlapping 800 kb segment containing 15 genes. Quantitative expression analysis of the genes from both patient samples and the SUDHL9 cell line revealed that CCND3 and BYSL (1.9 kb telomeric to the CCND3 gene locus) are the targets of 6p21 genomic gain/amplification.

CONCLUSIONS

Although it is known that t(6;14)(p21;q32) induces aberrant overexpression of CCND3 in B-cell malignancies, we were able to show that CCND3, which encodes the cyclin D family member protein that controls the G1-S phase of cell cycle regulation, can also be a target of genomic gain/amplification. Overexpression of CCND3 through genomic amplification is likely to lead to aberrant cell cycle control, although the precise biological role of BYSL with respect to tumorigenesis remains to be determined.

MASL1, a candidate oncogene found in amplification at 8p23.1, is translocated in immunoblastic B-cell lymphoma cell line OCI-LY8

Genetic amplification at chromosome 8p23.1 has been reported in some solid tumors. Translocation of 8p23.1 has also been reported in hematological malignancies and head and neck squamous cell cancer. In an attempt to clarify whether this translocation is implicated in lymphomagenesis, we performed FISH analysis of the immunoblastic B-cell lymphoma cell line OCI-LY8, which has chromosome translocation at 8p23.1, with various BAC clones. We found split signals on BAC, RP11-18L2 where the MASL1 gene is located. This translocation was found to produce a chimeric transcript of MASL1 exon 1 with a cryptic exon from the genome region at 14q21. Our study indicates that MASL1 is not only a target gene for genomic amplification but also for chromosomal translocation. Since tumorigenic activity of the MASL1 has not been proven, its in vitro transforming activity was studied and in vivo nude mice assay were performed. Although no in vitro transforming activity was detected by focus formation, the in vivo tumorigenesis assay with nude mice showed that both MASL1 and chimeric MASL1 possess tumorigenic activity. This suggests that MASL1 is an important oncogene not only for solid tumors but also for hematologic malignancies.

Stability and subcellular localization of API2-MALT1 chimeric protein involved in t(11;18) (q21;q21) MALT lymphoma

t(11; 18) (q21; q21) is a chromosomal aberration specific to low-grade mucosa-associated lymphoid tissue (MALT) lymphoma, and generates the chimeric product apoptosis inhibitor 2 (API2)-MALT1, which has been suggested to play an important role in MALT lymphomagenesis. However, little is known about the characteristics of API2, MALT1, and API2-MALT1 proteins. We therefore investigated the subcellular localization and stability of these products. API2 was localized in the nucleus and the cytoplasm, and MALT1 and API2-MALT1 in the cytoplasm only. Western blot analysis showed that the products of API2 and MALT1 were unstable, while the API2-MALT1 product was stable. The API2 deletion mutants at the end of the C-terminal and the MALT1 deletion mutants at the end of the N-terminal were stable compared with the full-length products. These results indicate that the domains responsible for protein instability are located in the end of the C-terminal of API2 and in that of the N-terminal of MALT1, and also that API2-MALT1 became stable because it lacks these domains. It has been suggested that NF-kappaB activation plays an important role in the tumorigenesis of MALT lymphoma. Our findings further suggest that the stabilized expression of API2-MALT1 products may continuously stimulate the NF-kappaB activating pathway, thus leading to MALT lymphomagenesis.

Heterogeneous copy numbers of API2-MALT1 chimeric transcripts in mucosa-associated lymphoid tissue lymphoma

T(11;18)(q21;q21) results in a chimeric transcript between API2 at 11q21 and MALT1 at 18q21 and is a characteristic chromosomal aberration of extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma). API2-MALT1 chimeric transcripts are present in approximately one-third of all cases of MALT lymphoma. MALT lymphoma is also known to have variations in histological features and tumor cell proportions. Real-time polymerase chain reaction (PCR) was used to examine number of API2-MALT1 copies in clinical samples for further investigation of the pathophysiology of MALT lymphoma. A total of 13 samples of MALT lymphoma contained API2-MALT1 transcripts from 1.7 x 10(-2) to 1.0 copies/beta-actin copy. These findings were compared to the proportions of tumor cells in genomic VDJ PCR products determined by Southern blotting. Tumor cell ratios varied widely among the patients' samples, and no significant correlation was found between transcript copy number and tumor cell ratio. These results suggest that copy numbers of API2-MALT1 do not reflect tumor cell proportions, and that the number of copies of API2-MALT1 in a tumor cell is different for each clinical sample.

Effects of 16 weeks of treatment with tibolone on bone mass and bone mechanical and histomorphometric indices in mature ovariectomized rats with established osteopenia on a low-calcium diet

Tibolone is a synthetic steroid with tissue-specific estrogenic, progestogenic, and androgenic properties. The therapeutic effects of tibolone on bone mass and strength, bone metabolic markers, and indices of histomorphometry were investigated in ovariectomized (ovx) rats on a low (0.1%)-calcium diet in comparison with 17alpha-ethynylestradiol (EE) or 1alpha-hydroxyvitamin D3 [1alpha(OH)D3]. Tibolone (0.1-3 mg/kg/day), EE (0.1 mg/kg/day), or 1alpha(OH)D3 (0.5 microg/kg/day) was administered orally once a day for 16 weeks, starting 12 weeks after ovariectomy, when the bone mineral density (BMD) of lumbar vertebrae (L4-5) and femur (global, proximal, and distal regions) had already been decreased by the combination of ovariectomy and low dietary calcium. The BMD of the lumbar vertebrae and the femur were higher in the groups treated with tibolone, EE, or 1alpha(OH)D3 than in the ovx control group. The BMD of the mid-diaphysial regions of femur and tibia, which consist mainly of cortical bone, were decreased 28 weeks after ovariectomy in the ovx control group. The BMD of the mid-diaphysial femur was higher in the groups treated with 1alpha-(OH)D3, and the BMD of mid-diaphysial tibia was higher in the groups treated with tibolone or 1alpha(OH)D3 than in the ovx control group. Like BMD, the compressive strength of the vertebral body of L2, corrected for the volume of each individual vertebra tested, was higher in the groups treated with tibolone, EE, or 1alpha(OH)D3 than in the ovx control group. Trabecular bone volume and trabecular number were reduced 12 and 28 weeks after ovariectomy but there was no change in trabecular thickness. These reduced indices were increased in the groups treated with tibolone, EE, or 1alpha(OH)D3 when compared with the ovx control group. Tibolone or EE decreased serum levels of osteocalcin and bone alkaline phosphatase and urinary levels of deoxypyridinoline and pyridinoline compared with the ovx control group. Furthermore, tibolone or EE decreased the mineralizing surface and bone formation rate as well as the osteoclast surface and osteoclast numbers. 1Alpha(OH)D3, however, did not affect these serum and urinary parameters. These data suggest that tibolone suppresses the accelerated bone turnover induced by a combination of ovariectomy and low dietary calcium, and indicate that tibolone may be a potentially useful drug for the treatment of postmenopausal osteoporosis.

Beta-decay half-lives and level ordering of 102m,gRh

Beta-decay half-lives of the ground state and an isomer of 102Rh have been determined 207.3(17) d and 3,742(10) y, respectively, by gamma-ray decay curves following each beta-decay. It has been found that a state (2-) which has a shorter half-life (207.3 d) is the ground state from the result that the half-life of the 41.9 keV isomeric gamma-transition was equal to 3.742 y. It has also been confirmed that the 41.9 keV transition is certainly an isomeric transition with X-gamma coincidence measurement.

Effects of tibolone (Org OD14) treatment for 3 months on ovariectomy-induced osteopenia in 8-month-old rats on a low-calcium diet: preventive testing for 3 months

Tibolone (Org OD14), (7alpha, 17alpha)-17-hydroxy-7-methyl-19-norpregn-5(10)-en-20-yn++ +-3-one, is a synthetic steroid with weak estrogenic, progestational, and androgenic properties. We investigated the prophylactic effects of tibolone on bone loss, bone strength, and plasma and urinary parameters in 8-month-old ovariectomized rats on a low-Ca diet. Oral administration of tibolone (0.03-3 mg/kg/day) was started immediately after ovariectomy (ovx) and continued for 3 months. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry. Oral administration of tibolone (1 or 3 mg/kg/day) significantly prevented a decrease in BMD and bone ash density (bone ash weight/volume) of the global femur, and BMDs in the femoral distal and proximal regions. Also in the lumbar vertebrae, the ovx-induced reduction in BMD was prevented by tibolone (1 and 3 mg/kg/ day) treatment, resulting in a significantly higher lumbar vertebral (L-2) bone compression strength compared to the ovx control group. Neither ovx alone nor supplemented with tibolone affected the BMD or bending strength of the femoral mid-diaphysial region. Tibolone (0.03-3 mg/kg/day) significantly reduced the ovx-induced increases in serum osteocalcin level. Furthermore, tibolone inhibited an increase in the urinary hydroxyproline/creatinine, pyridinoline/creatinine, and deoxypyridinoline/creatinine ratios induced by ovx. Tibolone also reduced body weight gain and serum cholesterol level, as has been reported for estrogen. These findings indicate that tibolone prevents reduction in bone mass associated with osteopenia by reducing increased trabecular bone resorption induced by a combination of ovx and a low-Ca diet.

Existence of parvalbumin and biochemical characterization in quail and pigeon skeletal muscles with different fiber type compositions

The localization of parvalbumin was determined in skeletal muscles with different fiber type compositions from quails (Coturnix japonica) and pigeons (Columba livia) by sandwich ELISA. The biochemical profiles of these muscles were evaluated by the assay of total lactate dehydrogenase (LDH) activity as well as the LDH isozymes for anaerobic metabolism, and by the analysis of myoglobin for aerobic metabolism. The quail fast posterior latissimus dorsi (PLD) with a lower myoglobin content and higher LDH activity or M-type isozyme pattern was assessed as containing primarily fast-twitch glycolytic and oxidative-glycolytic (FG/FOG) fibers, and the mixed sartorius (SA) in quails and pigeons was shown to be composed mostly of FOG fibers because of the intermediate myoglobin content and LDH activity or H/M-type isozyme pattern. Parvalbumin, which functions as a relaxing factor in the fast-twitch fibers, was present in PLD and SA in significant amounts, whereas it was undetectable in quail anterior latissimus dorsi (ALD) and pigeon latissimus dorsi (LD) which contain exclusively slow-tonic (ST) fibers with the lowest LDH activity or predominant H-type isozyme characteristics. The pectoralis superficialis (PS) and pectoralis profundus (PP) muscles from quails and pigeons seem to consist mostly of FG/FOG fibers because of the highest myoglobin contents and LDH activities or M-type and H/M-type isozyme patterns. Despite fast-twitch fiber compositions, parvalbumin was absent from these pectoralis muscles. The tetanic contraction induced in avian fast-twitch pectoralis fibers during flapping flight might be independent of a function of parvalbumin as a relaxing factor.

Distribution of parvalbumin in specific fibre types of chicken skeletal muscles

1. The distribution of parvalbumin (PA), which functions as a relaxing factor in the skeletal muscles, was examined in slow anterior latissimus dorsi (ALD), fast posterior latissimus dorsi (PLD), mixed sartorius (SA), pectoralis superficialis (PS) and pectoralis profundus (PP) muscles from chickens. 2. The biochemical characteristics of these muscles were confirmed by the assay of total lactate dehydrogenase (LDH) activity as well as the LDH isozymes for anaerobic metabolism, and by the photometrical analysis of myoglobin for anaerobic metabolism, and by the photometrical analysis of myoglobin for aerobic metabolism. 3. PA in individual muscles was determined by a sandwich ELISA and was demonstrated by 2-dimensional polyacrylamide-gel electrophoresis. 4. Because of poor myoglobin and higher LDH activity or M-type isozyme pattern, the PLD was confirmed as containing primarily fast-twitch glycolytic and oxidative-glycolytic (FG/FOG) fibres, while the SA was shown to be composed mostly of FOG fibres because of the highest myoglobin content and the intermediate LDH activity or H and M-type isozyme pattern. PA content was high and variable in both PLD and SA. 5. PA was undetectable in the ALD which appears to contain exclusively slow-tonic (ST) fibres, being verified by its myoglobin-rich nature and lowest LDH activity or predominant H-type isozyme characteristics. PA was absent from the PS ad PP, which probably contain predominantly FG fibres because of negligible amounts of myoglobin and the highest LDH activities or M-type isozyme pattern.

Synthesis and aldose reductase inhibitory activities of benzyl 2-oxazolecarbamate analogues

Various analogues of benzyl 5-phenyl-2-oxazolecarbamate (1a) were synthesized, and the structure-activity relationship of these analogues as aldose reductase inhibitor was studied. The carbamate group was necessary for the inhibitory activity. The introduction of an alkyl group at the C-4 position of 1a enhanced the inhibitory activity, however, the N-carboxymethyl group on the carbamate moiety counteracted to a hydrophobic interaction between the alkyl group at the C-4 position and the enzyme molecule.