Web survey-based selection of controls for epidemiological analyses of a multi-prefectural outbreak of enterohaemorrhagic Escherichia coli O157 in Japan associated with consumption of self-grilled beef hanging tender.

An outbreak of enterohaemorrhagic Escherichia coli O157 occurred in multiple prefectures of Japan in November 2009. We conducted two case-control studies with trace-back and trace-forward investigations to determine the source. The case definition was met by 21 individuals; 14 (66.7%) were hospitalised, but no haemolytic uraemic syndrome, acute encephalopathy or deaths occurred. Median age was 23 (range 12-48) years and 14 cases were male (66.7%). No significant associations with food were found in a case-control study by local public health centres, but our matched case-control study using Internet surveys found that beef hanging tender (or hanger steak), derived from the diaphragm of the cattle, was significantly associated with illness (odds ratio = 15.77; 95% confidence interval, 2.00-124.11). Pulsed-field gel electrophoresis analysis of isolates from patients and the suspected food showed five different patterns: two in faecal and food samples, and another three in patient faecal samples only, although there were epidemiological links to the meat consumed at the restaurants. Trace-back investigation implicated a common food processing company from outside Japan. Examination of the logistics of the meat processing company suggested that contamination did not occur in Japan. We concluded that the source of the outbreak was imported hanging tender. This investigation revealed that Internet surveys could be useful for outbreak investigations.

Prevention of secondary household transmission during Shiga toxin-producing Escherichia coli outbreaks.

Prevention of secondary household transmission of Shiga toxin-producing Escherichia coli (STEC) is important in outbreak settings. We examined factors contributing to secondary household transmission during STEC outbreaks in daycare centres in Japan. Suspected STEC outbreaks in daycare centres were identified by the National Epidemiological Surveillance of Infectious Diseases. Questionnaires were sent to local health centres that responded to outbreaks. Secondary household transmission rates were calculated, and factors affecting secondary household transmission rate were analysed by multilevel analysis. The secondary household transmission rates in 16 outbreaks ranged from 0% to 34·4% (median 4·4%). The highest rate (23·0%) was observed in siblings aged 6-9 years, and the infection rate was significantly higher for mothers than for fathers and grandparents (P < 0·05). Using multilevel analysis, the following variables were selected in the best model: information provided face-to-face (vs. letter or telephone) to families of children in daycare centres (at initial response), STEC type and lag time (days) between onset and providing information. Early response and hygiene education by visiting local health centre staff may be effective measures to prevent secondary household transmission in STEC outbreaks. Hygiene education should be emphasized for children aged 6-9 years, as well as for younger children.

Epidemiological analysis of a large enterohaemorrhagic Escherichia coli O111 outbreak in Japan associated with haemolytic uraemic syndrome and acute encephalopathy.

A large outbreak of enterohaemorrhagic Escherichia coli (EHEC) O111 and O157 occurred in Japan in April 2011. We conducted an unmatched case-control study and trace-back investigation to determine the source of EHEC O111 infection and risk factors for severe complications. Pulsed-field gel electrophoresis was performed to help define cases. A total of 86 individuals met the case definition. Of these, 40% experienced haemolytic uraemic syndrome (HUS), 24% acute encephalopathy, and 6% died. Illness was significantly associated with eating the raw beef dish yukhoe (odds ratio 19·64, 95% confidence interval 7·03-54·83), the likely food vehicle. EHEC O111 and its closely related stx-negative variants were found in the beef. HUS occurred most frequently in individuals aged 5-9 years, and this age group was significantly associated with acute encephalopathy. The prevalence of HUS and acute encephalopathy was higher than in previous non-O157-related outbreaks, indicating a high risk of severe complications.

Nano-indentation testing of new and fractured nickel-titanium endodontic instruments.

AIM: To investigate the effect of cyclic fatigue on nickel-titanium (NiTi) endodontic instruments using a nano-indentation test. METHODOLOGY: Eight ProFile NiTi rotary instruments (size 30, taper 0.06; Dentsply Maillefer, Ballaigues, Switzerland) were tested using a cyclic fatigue set-up until fracture. The fractured instruments and eight new NiTi instruments of the same size and taper were used for a nano-indentation test on the internal surfaces of a NiTi instruments in the region just adjacent to their fractured edge (group I) and in the same region of the new group (group II), and the cutting part beside the shaft for both instruments [group III (fractured) and group IV (new)]. Data were statistically analyzed using one-way analysis of variance and Games-Howell post hoc test. The alpha-type error was set at 0.05. RESULTS: Significant differences in terms of hardness and elastic modulus for each group (P < 0.05) were found, with group I having the lowest mean values followed by group III. Additionally, standard deviations increased remarkably after failure, as represented by groups I and III. CONCLUSION: The nano-indentation technique can be applied to determine the performance and the failure mechanism of NiTi instruments. The fatigue process revealed a significant decrease in the hardness and elastic modulus of the NiTi instrument. As indicated by the low hardness, the fatigue process did not result in work hardening but rather work softening.

Heat treatment of nickel-titanium rotary endodontic instruments: effects on bending properties and shaping abilities.

AIM: To evaluate the bending properties and shaping abilities of nickel-titanium endodontic instruments processed by heat treatment. METHODOLOGY: K3 files were heated for 30 min at 400 °C (group 400), 450 °C (group 450) and 500 °C (group 500). Files that were not heat treated served as controls. A cantilever-bending test was used to evaluate changes in specimen flexibility caused by heat treatment. Curved root canal models were prepared. The times required for preparation, deformation and fracture were recorded. Pre- and postoperative images were superimposed. The amounts of resin removed from both the inner and the outer sides of the curvature in the apical 6 mm were determined. RESULTS: In the cantilever-bending test, load values of the control group and group 500 were higher than those of groups 400 and 450 at the elastic range (P<0.05). At the superelastic range, the bending load of the control group was the highest amongst all groups (P<0.05). Regarding shaping ability, in the control group, root canals at the apex were transported more to the outer side of the curvature compared with those of all heat-treated groups (P<0.05). Root canals of group 400 at 3 mm from the apex were transported less compared with those of other groups (P<0.05). No significant difference was found in working time amongst the groups. In group 450, there was no plastic deformation or fracture of the file. CONCLUSIONS: Heat treatment of files might improve their flexibility, making them more effective for preparation of curved canals.

Phase transformation behaviour and bending property of twisted nickel-titanium endodontic instruments.

AIM: To investigate the relationship between phase transformation behaviour and bending property of nickel-titanium endodontic instruments manufactured by a twisting process. METHODOLOGY: The phase transformation behaviour and bending property of Twisted Files (TF; SybronEndo, Orange, CA, USA) and K3 (SybronEndo) with.06 taper and size 30 tip were investigated. K3 was used as control group. Phase transformation behaviour was estimated by differential scanning calorimetry (DSC). Transformation temperatures were calculated from the DSC curve. Bending load of the instruments was measured by cantilever-bending test at 37°C. Data were analysed by Student's t-test and Mann-Whitney U-test. RESULTS: The phase transformation temperatures of TF were significantly higher (P<0.05) than those of K3. The bending load values were significantly lower for TF than that of K3 (P<0.05), both in the elastic and super-elastic ranges. CONCLUSIONS: The new method of manufacturing NiTi instruments by twisting coupled with heat treatment might contribute to the increased phase transformation temperatures and superior flexibility.

Household transmission of pandemic 2009 influenza A (H1N1) virus in Osaka, Japan in May 2009.

OBJECTIVE: To assess household transmission of pandemic influenza A (H1N1) and effectiveness of postexposure prophylaxis (PEP) of antiviral drugs among household contacts of patients during the first pandemic influenza A (H1N1) outbreak in Osaka, Japan in May 2009. METHODS: Active surveillance of patients and their families was conducted. Public Health Center staff visited each home with an infected patient and advised every household member with regard to precautionary measures, and PEP was provided to household contacts to prevent secondary infection. We analyzed the effectiveness of PEP and characteristics of secondary infection. RESULTS: The secondary attack rate (SAR) among household contacts was 3.7%. The SAR among household contacts without PEP was 26.1%. However, the SAR among those with PEP was 0.6%. Only two of 331 household contacts with PEP became infected. One of the two was infected with an oseltamivir-resistant strain. Analysis of SAR by age group showed that those under 20 years of age were at higher risk than those over 20 (relative risk [RR] = 7.9; 95% confidence interval [CI] = 2.24-27.8). Significant differences with respect to sex, number of household contacts, and use of antiviral medications in the index cases were not observed. CONCLUSIONS: Our present results indicate that PEP is effective for preventing secondary H1N1 infection among household contacts.

Reversible myocardial hypertrophy induced by tacrolimus in a pediatric heart transplant recipient: case report.

Tacrolimus is a potent immunosuppressant that is frequently used in organ transplantation. However, adverse effects include cardiac toxicity. Herein we describe transient myocardial hypertrophy induced by tacrolimus after heart transplantation. The hypertrophy caused no clinical symptoms but was noted because of elevation of plasma brain natriuretic peptide concentration and confirmed at echocardiography. Initially, allograft rejection was feared; however, myocardial biopsy samples revealed only interstitial edema and mild myocardial hypertrophy; neither cellular nor humoral rejection was detected. The blood tacrolimus concentration was higher than usual at that time; thus, tacrolimus dosage was reduced. Myocardial hypertrophy completely resolved upon reducing the target concentration of tacrolimus and did not recur, as confirmed at echocardiography and myocardial biopsy. Thus, we conclude that tacrolimus induces reversible myocardial hypertrophy. In patients receiving tacrolimus therapy, blood concentration should be carefully controlled and extreme attention paid to cardiac involvement.

Assessment of secondary attack rate and effectiveness of antiviral prophylaxis among household contacts in an influenza A(H1N1)v outbreak in Kobe, Japan, May-June 2009.

This report describes the assessment of the secondary attack rate (SAR) and the effectiveness of post-exposure antiviral prophylaxis among household contacts in the first domestic outbreak of a novel influenza A(H1N1)v between mid-May and early June 2009 in Kobe city, Japan. Of the 293 subjects, 14 (4.8%) household contacts met the case definition and most secondary cases were probably infected around the time of symptom onset date of the respective index case. The SAR among household contacts who did not receive prophylaxis was 7.6%, similar to the rate of seasonal influenza, and the attack rate in siblings was significantly higher than that in parents. We conclude that it is important to establish routine infection control measures for households in order to prevent the spread of the virus among household contacts and, possibly, to the community. We could not conclude whether antiviral prophylaxis was effective or not. However, among close contacts with underlying disease who received prophylaxis, nobody developed a severe form of the disease.

Clinical features of cases of influenza A (H1N1)v in Osaka prefecture, Japan, May 2009.

This report describes the clinical characteristics of influenza A(H1N1)v virus infection in Osaka. By the end of May, 171 cases had been reported in Osaka. Most patients were from one school. No patient had a serious underlying medical condition.Clinical symptoms were mild and resembled those of seasonal influenza. The sensitivity of the rapid antigen test was 77%. Antivirals were given to the majority of the cases. Early antiviral treatment may have shortened the duration of fever.

Effect of heat treatment on transformation temperatures and bending properties of nickel-titanium endodontic instruments.

AIM: To investigate the effect of heat treatment on the bending properties of nickel-titanium endodontic instruments in relation to their transformation behaviour. METHODOLOGY: Nickel-titanium super-elastic alloy wire (1.00 mm Ø) was processed into a conical shape with a 0.30 mm diameter tip and 0.06 taper. The heat treatment temperature was set at 440 or 500 degrees C for a period of 10 or 30 min. Nonheat-treated specimens were used as controls. The phase transformation behaviour was examined using differential scanning calorimetry. A cantilever-bending test was used to evaluate the bending properties of the specimens. Data were analyzed by ANOVA and the Tukey-Kramer test (P = 0.05). RESULTS: The transformation temperature was higher for each heat treatment condition compared with the control. Two clear thermal peaks were observed for the heat treatment at 440 degrees C. The specimen heated at 440 degrees C for 30 min exhibited the highest temperatures for M(s) and A(f), with subsequently lower temperatures observed for specimens heated at 440 degrees C for 10 min, 500 degrees C for 30 min, 500 degrees C for 10 min, and control specimens. The sample heated at 440 degrees C for 30 min had the lowest bending load values (P < 0.05), both in the elastic range (0.5 mm deflection) and in the super-elastic range (2.0 mm deflection). The influence of heat treatment time was less than that of heat treatment temperature. CONCLUSIONS: Change in the transformation behaviour by heat treatment may be effective in increasing the flexibility of nickel-titanium endodontic instruments.

Phase transformation behaviour and bending properties of hybrid nickel-titanium rotary endodontic instruments.

AIM: To investigate the bending properties of hybrid rotary nickel-titanium endodontic instruments in relation to their transformation behaviour. METHODOLOGY: Four types of nickel-titanium rotary endodontic instruments with different cross-sectional shapes (triangular-based and rectangular-based) and different heat treatment conditions (super-elastic type and hybrid type with shape memory effect) were selected to investigate bending properties and phase transformation behaviour. Bending load of the instruments was measured in a cantilever-bending test at 37 degrees C with the maximum deflection of 3.0 mm. A commercial rotary instrument, ProFile (PF; Dentsply Maillefer, Ballaigues, Switzerland) was used as a reference for the bending test. Phase transformation temperatures were calculated from the diagrams obtained from differential scanning calorimetry. Data were analysed by anova and Scheffe's test. RESULTS: The bending load values of the hybrid type that had undergone additional heat treatment at the tip were significantly lower (P < 0.05) than those of the super-elastic type with no additional heat treatment. The bending load values of rectangular-based cross-sectional shaped instruments were significantly lower (P < 0.05) than those of triangular-based cross-sectional shaped instruments. Phase transformation temperatures (M(s) and A(f) points) of the hybrid type were significantly higher (P < 0.05) than the super-elastic type. The M(f) and A(s) points of the tip part were significantly higher (P < 0.05) than those of the whole part of the hybrid instrument. CONCLUSIONS: Additional heat treatment of hybrid nickel-titanium instruments may be effective in increasing the flexibility of nickel-titanium rotary instruments.

[Prevalence of disabilities of the upper and lower extremities among community-dwelling middle-aged and elderly women].

OBJECTIVE: In order to obtain baseline data for designing programs aimed at promoting physical function among elderly people in Japan, we determined the prevalence of disabilities affecting upper and lower extremities and their impact on function in community-dwelling middle-aged and elderly Japanese women. METHODS: Subjects were 580 women aged 40 years and over, living in Oshima town, Nagasaki, Japan. Information on disabilities affecting all four extremities was collected by questionnaire. Subjects were asked about the extent of disability in each extremity (no disability, some, moderate, cannot or very difficult to use extremity) and the reason for the disability. The functional level was defined using a disability score, calculated by summing the disabilities for upper or lower extremities (no disability, 0; some, 1; moderate, 2; cannot or very difficult to use, 3). Women who scored 0 were classified as 'good', women who scored 1-2 'fair', and who scored 3-6 as 'poor'. RESULTS: Prevalence of disability affecting the upper extremities increased significantly with age (11.9% with some or greater, and 4.3% with moderate or worse). Disabilities of the lower extremities also increased significantly with age (27.2% with some or greater, and 12.9% with moderate or worse), affecting a larger proportion of individuals. With regard to the upper extremities, the women classified a 'fair' and 'poor' increased significantly with age (9.5% with 'fair', and 2.4% with 'poor'), and function decreased (p = 0.003). The same was the case for the lower extremities (19.0% with 'fair', and 8.3% with 'poor') (P < 0.001). The most frequently cited cause of disability was arthritis, both in the upper (20%) and lower (40%) extremities, followed by stroke (10%), fracture (10%) and trauma not associated with fracture (10%). CONCLUSIONS: In middle aged and elderly women, disabilities of the upper and lower extremities become more prevalent and are associated with further functional impairment with aging. Such disabilities are more common in the lower extremities, and arthritis seems to be the most frequent cause.

Stiffness index of the calcaneus measured by quantitative ultrasound and menopause among Japanese women: The Hizen-Oshima Study.

Quantitative ultrasound (QUS) is a recently developed technique for evaluating fracture risk that can assess both bone mass and architecture. Although numerous studies have shown that menopause is associated with accelerated loss of bone mineral density, there are only a few studies on the association of QUS parameter (stiffness index) with menopausal status, especially among Japanese population. We examined age-specific changes in stiffness index, and relation with age, body mass index (BMI) and menopausal status among 506 community-dwelling Japanese women aged 40-89 years. Mean age at menopause (standard deviation) among 459 women with natural menopause was 49.4 (4.0) years. Stiffness index significantly decreased with increasing age. Stiffness index among 80-89 years age group was 40% lower, compared with that of 40-49 years age group. The greatest decline among adjacent ten-year age groups in stiffness index (15%) was found between 40-49 and 50-59 years of age. Multiple regression analysis showed that menopause related with decreased stiffness index, independent of age and BMI. Our findings indicate that menopause influences loss of bone mass and induces deterioration of bone trabecular microstructure.

Calcaneus bone mineral density is lower among men and women with lower physical performance.

Fracture risk is influenced by both bone strength and by falls. Measures of physical function and performance are predictors of falls. However, the interrelationships among bone mineral density (BMD), regular physical activity, and measures of physical performance are not well known. We studied 447 community-dwelling Japanese people aged 40 years and over (96 men and 351 women) to examine the association of calcaneus BMD with measures of physical performance (grip strength, walking speed, chair stand, and functional reach) and regular physical activity. Calcaneus BMD decreased with age by approximately 25% in men and 42% in women. Measures of physical performance decreased with age by approximately 30% in both genders, however, performance on the chair stand test declined by approximately 60%. There were only minimal differences in performance measures and calcaneus BMD between people with and those without regular physical activity in both genders, and most differences were not significant. However, there were significant BMD increases of 3-6% per standard deviation (SD) increase in all performance measures for women and a 7% increase in BMD per SD increase in grip strength for men, after adjusting for age. These associations remained after additional adjustment for body mass index and regular physical activity. These findings suggest that bone density and physical function decline markedly in both men and women with age, and that low BMD and poor function tend to occur together, which would increase fracture risk more than either risk factor alone.

Knowledge and attitudes toward AIDS among female college students in Nagasaki, Japan.

This study assesses knowledge and attitudes concerning HIV infection and individuals with AIDS among 383 female students attending colleges in Nagasaki, Japan. A structured questionnaire containing questions concerning knowledge about AIDS, sources of information, beliefs and attitudes toward people with HIV/AIDS was administered during sessions set up for that purpose. The mean age of participants was 18.8 +/- 0.8 years (+/- SD). The main source of information for AIDS awareness as reported by the students was the mass media. Good knowledge about AIDS was positively associated with ease of acceptance of living in the same house with a person diagnosed with AIDS [odds ratio (OR): 1.90; 95% confidence interval (CI): 1.07-3.38]. However, residing at home (OR: 0.64; 95% CI: 0.42-0.98) and involvement in nurse education programmes (OR: 0.59; 95% CI: 0.37-0.95) showed a negative association. Students demonstrated a high level of knowledge concerning AIDS and HIV, but had considerable misconceptions and prejudices about people having HIV/AIDS. Our results suggest that a more appropriate education programme in colleges in Japan may be necessary to reduce the discrepancy between general knowledge and desirable attitude regarding HIV/AIDS.

[Investigation of factors affecting psychological depression in child-rearing mothers].

Child-rearing mothers (n = 1,459) were surveyed by questionnaire in regard to their feeling psychologically depressed and for prevalence of some conditions in their life frequently referred to as affecting factors that may be rated to the depression. A working scale of depression for this research was developed through a Multi Dimensional Scaling Procedure. Crobach's alpha of this scale was as large as 0.77 and correlational coefficients of this scale between each question were greater than 0.46 and less than 0.70. This scale was considered sufficient for the purpose of this research to obtain depressive scores. Coefficients in multiple regression analysis predictive for depressive score were obtained. Correlations were also calculated between depressive score and the factors stratifying by mothers' demographic factors. Out of a total 21.6 coefficients only 14 were greater than 0.30 and no factor showed coefficients greater than 0.80 through all the stratifications. None of the factors analyzed in this study appear to satisfactorily explain psychological depression. Therefore further search for real factors that affect the psychological depression in child-rearing mothers is required.

Severe hypersensitivity syndrome due to sulfasalazine associated with reactivation of human herpesvirus 6.

BACKGROUND: A severe adverse reaction to sulfasalazine therapy has been associated with hypersensitivity syndrome, the clinical features of which are similar to infectious mononucleosis. No serologic evidence of viral infections has been reported with this syndrome; however, human herpesvirus 6 infection has not been specifically investigated, which could cause an infectious mononucleosislike syndrome. OBSERVATIONS: We report 2 cases of hypersensitivity syndrome induced by the use of sulfasalazine. The clinical features of the syndrome appeared 18 and 32 days after administration of sulfasalazine. Clinical signs included a maculopapular rash progressing to exfoliate erythroderma, fever, and lymphadenopathy. Leukocytosis, atypical lymphocytes, liver dysfunction, and renal disturbance were also observed. In 1 patient, human herpesvirus 6 variant B was isolated from peripheral blood mononuclear cells, and in both patients anti-human herpesvirus 6 IgG titers increased considerably. CONCLUSIONS: Two cases of hypersensitivity syndrome due to sulfasalazine use were associated with the reactivation of human herpesvirus 6, which may be a required cause of hypersensitivity syndrome.

Polyclonal B-cell lymphocytosis with features resembling hairy cell leukemia-Japanese variant.

Polyclonal B lymphocytosis was found in four patients having clinical and hematologic features resembling those of hairy cell leukemia (HCL). All four patients were women between 37 and 67 years of age. Three patients had splenomegaly. Lymphadenopthy was absent or slight. Persistent lymphocytosis was seen in all the patients, and anemia and/or thrombopenia was observed in three of the patients. Abnormal lymphocytes have long microvilli and prominent membranous ruffles on their surfaces. Bone marrow aspirates and biopsy specimens showed increased numbers of abnormal lymphocytes with round nuclei and abundant pale cytoplasm. Although these findings were similar to those of HCL, studies of Ig gene rearrangements and expression showed the polyclonal proliferation of B cells. We called this new disease hairy B-cell lymphoproliferative disorder (HBLD). All four patients exhibited a polyclonal increase in serum IgG. The morphology of the cells in HBLD was more similar to that of leukemia cells of a variant form of HCL (HCL-Japanese variant) than to typical HCL cells. The surface IgG+, CD5-, CD11c+, CD22+, CD24-, CD25- phenotype and the weak tartrate-resistant acid phosphatase activity in the cells were identical to those of HCL cells of the Japanese variant. Our findings suggest that the B cells in HBLD are the nonmalignant counterpart of leukemic B cells in HCL-Japanese variant.