[Comparison of diagnostic criteria for the metabolic syndrome among Japanese university faculty]

OBJECTIVES

Diagnostic criteria for the metabolic syndrome (Mets) in Japan have been set by the Medical Committee of the Japanese Association of Medical Sciences (Med), the National Health and Nutrition Examination Survey (Nat), specific health checkups (Ckup), and second medical examination by Worker's Accident Compensation Insurance System (Wor). The purpose of this study was to compare classification of the metabolic syndrome by different organizational criteria and to investigate underlying differences.

METHODS

All faculty members of a university in Osaka, Japan, underwent mandatory health checkups in September 2008. The demographic distribution included 769 males (mean age, 49 +/- 12 years) and 415 females (mean age, 43 +/- 10 years). Using the Med, Nat, Ckup and Wor criteria, individuals were assessed for the MetS and pre-metabolic syndrome (pre-Mets), strongly suspected metabolic syndrome (S-Mets) and assumed pre-metabolic syndrome (A-pre-Mets), as well as a positive support level (PSL) and a motivational support level (MSL). All faculty members were categorized into a morbid group (Mets, S-Mets, PSL, and FB) or a pre-morbid group (pre-Mets, A-pre-Mets, and MSL) based on medical data and smoking habits. The incidence of morbid and pre-morbid individuals was compared across the four criteria and analyzed based on gender and age (under 40 and 40 or over).

RESULTS

Male incidences for the morbid and pre-morbid classifications were 17% and 20% with Med, 9% and 23% with Nat, 27% and 14% with Ckup, and 1.4% and 0% with Wor. There were significant differences across criteria sets in both the morbid and pre-morbid groups, with significantly greater numbers of males than females, and higher prevalences in those aged 40 or over than in their younger counterparts. Males aged under 40 classified into the pre-morbid group comprised 18% in Med, 16% in Nat, and 13% in Ckup.

CONCLUSION

The different disease incidences found between Med and Ckup data in males aged 40 or over might be attributed to varying criteria for blood glucose levels, while Wor data may be influenced by the higher level of blood pressure set as a criterion with this approach. It will be important to continuously validate currently established criteria to identify the actual prevalence of MetS in Japan. Furthermore, incorporation of waist circumference and BMI for females, and a positive approach for young males, may be critical for future developments.

The Roles of Angiotensin II in Stretched Periodontal Ligament Cells

The loading caused by occlusion and mastication plays an important role in maintaining periodontal ligament (PDL) tissues. We hypothesized that a loading magnitude would be involved in the production of biological factors that function in the maintenance of PDL tissues. Here, we identified up-regulated gene expressions of transforming growth factor-β1 (TGF-β1), alkaline phosphatase (ALP), and angiotensinogen in human PDL fibroblastic cells (HPLFs) that were exposed to 8% stretch loading. Immunolocalization of angiotensin I/II (Ang I/II), which was converted from angiotensinogen, was detected in rat PDL tissues. HPLFs that were stimulated by Ang II also increased their gene expressions of TGF-β1 and ALP. Furthermore, the antagonist for Ang II type 2 receptor, rather than for type 1, significantly inhibited gene expressions induced by the stretch loading. Analysis of these data suggests that Ang II mediates the loading signal in stretched HPLFs to induce expressions of TGF-β1 and ALP.

Point-contact transport properties of strongly correlated electrons on liquid helium

We present transport measurements of a nondegenerate two-dimensional electron system on the surface of liquid helium at a point constriction. The constriction is formed in a microchannel by a split gate beneath the helium surface. The electrostatic energy of the electron system, which depends in part on the electron density, determines the split-gate voltage threshold of current flow through the constriction. Steplike increases in conductance are observed as the confinement strength is reduced. As the Coulomb interaction between electrons is strong, we attribute this effect to the increase in the number of electrons that can pass simultaneously through the constriction. Close to the threshold, single-electron transport is observed.

[Systematic training for occupational physicians in schools of public health in the US and its application to Japan's system--Master of Public Health Program at Harvard School of Public Health]

OBJECTIVES AND RESULTS

Globalization has progressed tremendously resulting in far-reaching changes in the work environment. In Japan, occupational health and safety (OSH) activities are performed under and improved by regulations. However, this system is not likely to satisfy the unceasing diversification of social demand for OSH in recent years. The US adopts a self-imposed OSH system with responsibility carried by employers under a system of minimum regulation. This paper introduces the systematic training for occupational physicians in schools of public health in the US, which is creating a base of OSH professionals who can meet social demand.

DISCUSSION

To satisfy the diverse demand for recent OSH, it is essential to improve the basic skills of occupational physicians and other OSH professionals by offering systematic training in Japan. Some examples of systematic training for occupational physicians in schools of public health in the US are discussed with the goal of improving Japan's future OSH.

NK cell dysfunction with down-regulated CD16 and up-regulated CD56 molecules in patients with esophageal squamous cell carcinoma

NK cells can be divided into two subsets, CD56(dim) and CD56(bright) NK cells, based on their expression of CD56 and CD16. In the present study, we analyzed NK cell dysfunction in patients with esophageal squamous cell carcinoma (ESCC), with a particular focus on the expression of CD16 and CD56 molecules. Expression of CD16 and CD56, and the distribution of CD56(dim) or CD56(bright) NK cells gated on CD56(+)CD3(-) NK cells were compared between ESCC patients (n= 40) and healthy donors (n= 38). Purified NK cells were evaluated for Cetuximab-mediated antibody-dependent cellular cytotoxicity (ADCC) against epidermal growth factor receptor (EGFR)-expressing ESCC cell lines. Although there were no significant differences in the distribution of CD56(dim) and CD56(bright) NK cells between ESCC patients and healthy donors, down-regulated CD16 and up-regulated CD56 were significantly observed on NK cells of ESCC patients, paralleling the impairment of Cetuximab-mediated ADCC, in comparison with healthy donors. After patients received curative resections of ESCC, the down-regulated CD16 and up-regulated CD56 were significantly restored to the levels of healthy donors. Moreover, TGF-beta1 partially contributed to down-regulation of CD16 on NK cells. Down-regulated CD16 and up-regulated CD56 molecules on NK cells were observed in ESCC patients, resulting in NK cell dysfunction.

Toxicological aspects of cadmium and occupational health activities to prevent workplace exposure in Japan: A narrative review

Chemicals are an essential part of modern manufacture processes. Their use must be managed with great attention in occupational settings to avoid serious detrimental effects to the health of employees. For example, cadmium compounds are indispensable for the production of nickel-cadmium rechargeable batteries or as chemical stabilizer in plastics. It is an exceptionally toxic heavy metal and personnel exposed to cadmium in the workplace meet with potential health risks that can lead to the development of kidney, skeletal and respiratory disorders. In consequence, proactive and systematical development of occupational hygiene and health activities are necessary to reduce chemical exposure to cadmium in the workplace. This review describes the known facts of cadmium toxicity, the biological effects of cadmium exposure, possible regulation measures to prevent occupational cadmium exposure in three industrial health management systems and discusses future cooperation programs in these systems, proactive safety activities and occupational safety and health management strategies.

A stable ATP binding to the nucleotide binding domain is important for reliable gating cycle in an ABC transporter CFTR

Cystic fibrosis transmembrane conductance regulator (CFTR) anion channel, a member of ABC transporter superfamily, gates following ATP-dependent conformational changes of the nucleotide binding domains (NBD). Reflecting the hundreds of milliseconds duration of the channel open state corresponding to the dimerization of two NBDs, macroscopic WT-CFTR currents usually showed a fast, single exponential relaxation upon removal of cytoplasmic ATP. Mutations of tyrosine1219, a residue critical for ATP binding in second NBD (NBD2), induced a significant slow phase in the current relaxation, suggesting that weakening ATP binding affinity at NBD2 increases the probability of the stable open state. The slow phase was effectively diminished by a higher affinity ATP analogue. These data suggest that a stable binding of ATP to NBD2 is required for normal CFTR gating cycle, andthat the instability of ATP binding frequently halts the gating cycle in the open state presumably through a failure of ATP hydrolysis at NBD2.

Inverse correlation of HER2 with MHC class I expression on oesophageal squamous cell carcinoma

BACKGROUND

As HER2 is expressed in 30% of oesophageal squamous cell carcinomas (ESCCs), T-cell-based immunotherapy and monoclonal antibodies targeted against HER2 are attractive, novel approaches for ESCCs. However, it was shown that there is an inverse correlation between HER2 and MHC class I expression on tumours. Thus, the correlation between HER2 and MHC class I expressions on ESCC was evaluated.

METHODS

Expressions of MHC class I and HER2 in ESCC tissues (n=80) and cell lines were assessed by immunohistochemistry, fluorescence in situ hybridisation (FISH), and flow cytometry. We investigated whether HER2 downregulation with small interfering RNA (siRNA) in ESCC cell lines could upregulate the expression of MHC class I and the antigen presentation machinery components, and could increase their sensitivity for tumour antigen-specific CTLs.

RESULTS

There was an inverse correlation between HER2 and MHC class I expressions in both tumour tissues and cell lines. Downregulation of HER2 with siRNA resulted in the upregulation of MHC class I expression, leading to increased CTL recognition by tumour antigen-specific CTLs.

CONCLUSION

HER2-overexpressing ESCC tumour cells showed a reduced sensitivity for CTLs through the downregulation of MHC class I.

CCL17 and CCL22 chemokines within tumor microenvironment are related to infiltration of regulatory T cells in esophageal squamous cell carcinoma

It has been reported that an increased population of regulatory T cells (T-regs) is one of the reasons for impaired anti-tumor immunity. We investigated the frequency of Foxp3(+) T-regs in tumor-infiltrating lymphocytes (TILs) and peripheral blood lymphocytes (PBLs) of patients with esophageal squamous cell carcinoma (ESCC). Furthermore, in order to elucidate the mechanisms behind T-regs accumulation within tumors, we evaluated the relationship between CCL17 or CCL22 expression and the frequency of Foxp3(+) T-regs. CD4(+)CD25(+)Foxp3(+) T-regs as a percentage of CD4(+) cells were counted by flow cytometry. The frequency of CCL17(+) or CCL22(+) cells among CD14(+) cells in tumors was also evaluated by flow cytometry. Moreover, an in vitro migration assay using T-regs derived from ESCC was performed in the presence of CCL17 or CCL22. The frequency of Foxp3(+) T-regs in TILs was significantly higher than that in the normal esophageal mucosa (24.6 +/- 10.0 vs 7.1 +/- 5.9%, P < 0.01). The frequency of Foxp3(+) T-regs in PBLs of ESCC patients was significantly higher than that in normal healthy donors (7.0 +/- 4.2 vs 2.5 +/- 1.0%, P < 0.01). Furthermore, the frequency of CCL17(+) or CCL22(+) cells among CD14(+) cells within tumors was significantly higher than that of normal esophageal mucosa, and there was a significant correlation between the frequency of CCL17(+) or CCL22(+) cells and Foxp3(+) T-regs in TILs. In addition, the in vitro migration assay indicated that T-regs were significantly induced to migrate by CCL17 or CCL22. In conclusion, CCL17 and CCL22 within the tumor are related to the increased population of Foxp3(+) T-regs in ESCC.

Association between the Trail Making Test and physical performance in elderly Japanese

AIM

The Trail Making Test (TMT) is used in Western countries as an indicator of executive function, but there is little information regarding its use in Japan. Our previous initial study showed that the TMT was significantly associated with mobility-related functions among elderly Japanese living in the community and in this study, we increased the number of participants to clarify that result.

METHODS

The TMT, comprised of two parts (part A and part B), was administered to 493 subjects aged 65 years or older (164 men, 329 women). Our assessment used the time difference (DeltaTMT) between parts B and A, and eight physical performance indicators: four of preventive care (usual walking speed, timed Up & Go [TUG], one-leg standing balance and handgrip strength) and four movement parameters (maximum walking speed, dual-task TUG, stair climbing and obstacle-negotiating gait).

RESULTS

The median DeltaTMT score was 64.01 s for men and 65.56 s for women. The DeltaTMT score increased with age, and there was no difference between sexes. Multinomial logistic regression analysis showed that a poor DeltaTMT was related to low tertiles for all physical performances. It related to the intermediate tertile of TUG and maximum walking speed, dual-task TUG, stair climbing and obstacle-negotiating gait.

CONCLUSION

The TMT reflects complex walking performance, so it can be a useful synthetic indicator for health programs promoting independence in elderly Japanese.

Enteroviruses, type 1 diabetes and hygiene: a complex relationship

Type 1 diabetes (T1D) is an autoimmune disease in which the immune system mounts an attack on the host's insulin‐producing β cells. Because most cases of T1D cannot be attributed only to individual genetics, it is strongly inferred that there is a significant environmental contribution, such as infection, impacting disease development. The human enteroviruses (HEV) are common picornaviruses often implicated as triggers of human T1D, although precisely which of the numerous HEV may be involved in human T1D development is unknown. Experiments using non‐obese diabetic (NOD) mice, commonly used to model T1D, show that induction of T1D by HEV infection in NOD mice is a multifactorial process involving both the virus and the host. Interestingly, results demonstrate that HEV infection of NOD mice can also induce long‐term protection from T1D under certain conditions, suggesting that a similar mechanism may occur in humans. Based upon both experimental animal and observational human studies, we postulate that HEV have a dual role in T1D development and can either cause or prevent autoimmune disease. Whichever outcome occurs depends upon multiple variables in the host‐virus equation, many of which can be deduced from results obtained from NOD mouse studies. We propose that the background to the sharply rising T1D incidences observed in the 20th century correlates with increased levels of hygiene in human societies. Viewing T1D in this perspective suggests that potential preventative options could be developed. Copyright © 2009 John Wiley & Sons, Ltd.

Evaluation of epidemiological studies of intestinal bacteria that affected occurrence of colorectal cancer: studies of prevention of colorectal tumors by dairy products and lactic acid bacteria

Enviromental factors have been consistently associated with colon cancer risk. In particular, consumption of Western-style diet including red meat is the most widely accepted etiologic risk factor. It has been reported that dietary factors change the proportion of intestinal flora, and it also affects the composition of fecal bile acids and the intestinal activity of some mutagens. In addition, it was suggested that modulating the composition of intestinal flora may reduce the occurrence of colorectal cancer. In this review, we present the clinical studies on the association between intestinal flora and the risk of colorectal cancer that have been carried out to date. The clinical studies of intestinal bacteria related to colorectal cancer risk have not shown consistent results so far, compared with the accomplishments of some basic studies. On the other hand, it was suggested in some clinical studies that lactic acid bacteria reduce the occurrence of colorectal cancer.

Spin bottleneck in resonant tunneling through double quantum dots with different Zeeman splittings

We investigated the electron transport property of the InGaAs/GaAs double quantum dots, the electron g factors of which are different from each other. We found that in a magnetic field, the resonant tunneling is suppressed even if one of the Zeeman sublevels is aligned. This is because the other misaligned Zeeman sublevels limit the total current. A finite broadening of the misaligned sublevel partially relieves this bottleneck effect, and the maximum current is reached when interdot detuning is half the Zeeman energy difference.

[Aging changes in muscle mass of Japanese]

AIM

The purpose of this study is To examine the influence of age on muscle mass in a Japanese population for health promotion.

METHODS

Subjects were 4,003 community-dwelling Japanese men and women. We employed four-frequency bioelectrical impedance analysis to estimate upper and lower limbs, trunk and whole body muscle mass.

RESULTS

Men showed significantly more muscle mass in all parts of the body compared to women. There was a curvilinear relationship between age and muscle mass in both men and women. For all parts of the body, the slope of the regression line between age and muscle mass was greater in men than women. The changes in muscle mass with advancing age were different in each part of the body. In the upper limbs, there was little change with advancing age in both men and women. In the lower limbs, the decrease in muscle mass began after two decades, with the reduction in this muscle mass the greatest of all parts of the body with advancing age. In the trunk, the slope of the regression line increased from the second to the fifth decade, after which the slope decreased.

CONCLUSIONS

These findings indicated that lower limb muscle mass was the first to begin to decrease and also showed the greatest decrease. For health promotion, it was seen as important to maintain muscle mass from at least middle age, with particular emphasis on the lower limbs.

Significance of fecal deoxycholic acid concentration for colorectal tumor enlargement

Deoxycholic acid (DCA) has been shown to promote proliferation of colonic carcinoma cells in many fundamental studies. However, no large-scale prospective clinical study providing direct evidence for an association of DCA with progress of colorectal tumor development in humans has been reported to date. To address this question, we conducted a two-step epidemiological study applying enzyme-linked immunosorbent assays to measure fecal cholic acid (CA) and DCA concentrations. Firstly, we compared bile acid concentrations of fecal samples from 366 patients who had multiple colorectal tumors removed endoscopically (tumor group) with those from 24 controls without abnormality in their large intestine (control group). Secondly, the tumor group was followed-up to evaluate the association between fecal bile acid concentrations and recurrence of colorectal tumors four years later. Fecal DCA level in the tumor group were significantly higher than that in the controls, whereas there was no difference in CA levels between the two groups. In the tumor group, a subgroup with high DCA level had higher recurrence risk of large adenomas (> 3 mm) four years later than the low DCA subgroup (odds ratio:1.85, 95% confidence interval: 1.12-3.05). This trend was observed more strongly in the left side colon. In conclusion, a high fecal DCA concentration may be a promoter of colorectal tumor enlargement.