Incidence of overwork-related mental disorders and suicide in Japan

Background

Mental disorders and suicide resulting from overwork or work-related stress have become major occupational health issues worldwide, particularly in Asian countries. However, no studies have reported incidence rates of mental disorders and suicide by sex, age group and industry, using a national database containing all cases involving compensation in Asian countries.

Aims

The present study examined incidence rates of occupational mental disorders and suicide by sex, age group and industry using a database containing all cases involving compensation for mental disorders and suicide in Japan over a 5-year period.

Methods

Cases involving compensation for mental disorders and suicide in Japan between January 2010 and March 2015 were analysed. Incidence rates over the 5-year study period were calculated by sex, age group and industry.

Results

In total, 1990 cases involving compensation for mental disorders and suicide (619 women and 1371 men) between January 2010 and March 2015 were analysed. The incidence rate involving compensation was higher in employees aged between 30 and 39 years. In men, incidence rates were higher in 'accommodation/eating/drinking services', 'information/communication' and 'scientific research, professional and technical services'. In these industries, incidence rates were particularly high for those aged 29 years or younger.

Conclusions

Our findings highlight the importance of promoting mental health support for younger employees and increasing awareness of their working conditions. Differences in incidence rates by sex, age and industry should be taken into consideration in the development of a national policy and industry- and age-specific preventive measures for overwork-related mental disorders and suicide.

Peripheral administration of κ-opioid receptor antagonist stimulates gonadotropin-releasing hormone pulse generator activity in ovariectomized, estrogen-treated female goats

Pulsatile gonadotropin-releasing hormone (GnRH) secretion is indispensable for reproduction in mammals. Kisspeptin neurons in the hypothalamic arcuate nucleus (ARC), referred to as KNDy neurons because of the coexpression of neurokinin B and dynorphin A, are considered as components of the GnRH pulse generator that produces rhythmic GnRH secretion. The present study aimed to investigate if peripheral administration of PF-4455242, a κ-opioid receptor (KOR, a dynorphin A receptor) antagonist, facilitates pulsatile luteinizing hormone (LH) secretion and GnRH pulse generator activity in estrogen-treated ovariectomized Shiba goats to determine the possibility of using KOR antagonists to artificially control ovarian activities. PF-4455242 was intravenously infused for 4 h (1 or 10 μmol/kg body weight/4 h) or as a single subcutaneous injection (1 or 10 μmol/kg body weight). In a separate experiment, the same KOR antagonist (10 μmol/kg body weight/4 h) was intravenously infused during the recording of multiple unit activity (MUA) in the ARC that reflects the activity of the GnRH pulse generator to test the effects of KOR antagonist administration on GnRH pulse generator activity. Intravenous infusion and single subcutaneous injection of the KOR antagonist significantly increased the frequency of LH pulses compared with controls. Intravenous infusion of KOR antagonist also significantly increased the frequency of episodic bursts in the MUA. The present study demonstrates that peripherally administered KOR antagonist stimulates pulsatile LH secretion by acting on the GnRH pulse generator, and peripheral administration of PF-4455242 can be used to facilitate pulsatile LH secretion, which in turn facilitates ovarian activities in farm animals.

Factors associated with possession of accurate knowledge regarding occupational health management among operations leaders of radiation decontamination workers in Fukushima, Japan: a cross-sectional study

OBJECTIVES

An operations leader (OL) takes an important role in occupational health management for radiation decontamination workers in Japan, and candidates for the position must participate in a training session to acquire the necessary knowledge as required by law. However, it has not been clarified whether the candidates for the OL position actually possess accurate knowledge regarding occupational health management for such work after the training session. We, therefore, aimed at examining the current occupational health management knowledge among the candidates and investigating factors related to the knowledge, with hypothesis that possession of accurate knowledge is associated with prior experience of having worked in radiation decontamination.

DESIGN

A cross-sectional study.

SETTING

The training sessions held by Fukushima Prefecture Labor Standard Associations in Fukushima, Japan, in 2017.

PARTICIPANTS

Eighty male candidates participated in the training sessions.

OUTCOME

The number/proportion of correct answers to the questions regarding occupational health management, such as those on working environment management, control of operations and health management.

RESULTS

The proportion of those who possessed accurate knowledge regarding working environment management, control of operations and health management was 68.8%, 55.0% and 51.2%, respectively. Experience of radiation decontamination work was associated with the possession of inaccurate knowledge regarding working environment management (OR 0.140 (95% CI 0.042 to 0.464)), and the uncertainty of future radiation decontamination work schedules in difficult-to-return zones was associated with the possession of accurate knowledge regarding health management (OR 4.344 (95% CI 1.509 to 12.50)).

CONCLUSIONS

Previous experience in radiation decontamination work may hinder the ability to acquire accurate information regarding working environment management among candidates for an OL position. To promote adequate occupational health management for radiation decontamination workers, it is required to establish an effective instructional method for the OL candidate training sessions with consideration of previous relevant experience.

Clinical benefit of high resolution anorectal manometry for the evaluation of anal function after intersphincteric resection

AIM

Intersphincteric resection (ISR) is an advanced anus-preserving operation for treating low rectal cancer while avoiding colostomy. High-resolution anorectal manometry (HR-ARM) allows objective and accurate evaluation of anal function. However, correlations between anal function after ISR and HR-ARM parameters are unknown. The aim of the study was to evaluate HR-ARM for objective evaluation of anal function after ISR.

METHOD

A total of 81 patients who underwent ISR at our hospital between October 2014 and March 2016 were identified from our prospectively collected database and electronic medical records. Of these, 68 patients who had been evaluated using HR-ARM both before and after ISR were included in the study. Faecal incontinence (FI) was assessed by Wexner score. Multivariate analysis was performed to determine risk factors for severe FI after ISR.

RESULTS

Maximum resting pressure (MRP) (P < 0.001) and maximum squeeze pressure (P = 0.04) were significantly lower after ISR, and MRP (P < 0.001) and maximum squeeze pressure (P = 0.02) were significantly lower after total (or subtotal) ISR than after partial ISR. The overall incidence of severe FI after ISR was 18% (12/68), and a high pressure zone before ISR ≤ 3 cm (P = 0.007) and MRP before ISR > 60 mmHg (P = 0.02) were independently associated with an elevated incidence of severe FI after ISR. Decreased preoperative MRP also correlated with severe FI after ISR (P = 0.008).

CONCLUSION

HR-ARM is reliable for the evaluation of anal function after ISR, and the high pressure zone and MRP may be useful preoperative predictors of severe FI after ISR.

Faecal freezing preservation period influences colonization ability for faecal microbiota transplantation

AIMS

There has been growing interest in faecal microbiota transplantation (FMT) as treatment. Although, frozen donor faeces preserved at -20°C has been widely used for practical advantages, freezing at -20°C can affect bacterial viability. Adequacy evaluation of fresh and frozen faeces as the transplant is necessary for the methodological improvement of FMT.

METHODS AND RESULTS

The viable bacterial compositions of faecal specimens under fresh and freezing conditions were compared by a microbiome analysis using propidium monoazide (PMA microbiome). In addition, recovery abilities from bacterial reduction by antibiotics were compared between fresh and frozen FMT using a murine model. PMA microbiome results suggested that freezing and freeze-thawing did not significantly affect in vitro faecal bacterial viability. However, the recovery effect from antimicrobial cleansing in frozen FMT was reduced in a freezing time-dependent manner, especially prominent in Actinobacteria and Bacteroidetes phyla.

CONCLUSIONS

Short-term freezing preservation of faeces exhibited maintenance of enteric colonization ability in frozen FMT in comparison to 1 month -20°C-preservation.

SIGNIFICANCE AND IMPACT OF THE STUDY

Long-term -20°C-preservation of transplanted faeces can result in instability of the clinical outcome in FMT therapy. The standardization of practical procedures of FMT therapy according to disease types is desirable.

Role of the Apparent Diffusion Coefficient as a Predictor of Tumor Progression in Patients with Chordoma

BACKGROUND AND PURPOSE

Diffusion-weighted imaging may aid in distinguishing aggressive chordoma from nonaggressive chordoma. This study explores the prognostic role of the apparent diffusion coefficient in chordomas.

MATERIALS AND METHODS

Sixteen patients with residual or recurrent chordoma were divided postoperatively into those with an aggressive tumor, defined as a growing tumor having a doubling time of <1 year, and those with a nonaggressive tumor on follow-up MR images. The ability of the ADC to predict an aggressive tumor phenotype was investigated by receiver operating characteristic analysis. The prognostic role of ADC was assessed using a Kaplan-Meier curve with a log-rank test.

RESULTS

Seven patients died during a median follow-up of 48 months (range, 4-126 months). Five of these 7 patients were in the aggressive tumor group, and 2 were in the nonaggressive tumor group. The mean ADC was significantly lower in the aggressive tumor group than in the nonaggressive tumor group (P = .002). Receiver operating characteristic analysis showed that a cutoff ADC value of 1.494 × 10^-3 × mm²/s could be used to diagnose aggressive tumors with an area under the curve of 0.983 (95% CI, 0.911-1.000), a sensitivity of 1.000 (95% CI, 0.541-1.000), and a specificity of 0.900 (95% CI, 0.555-0.998). Furthermore, a cutoff ADC of ≤1.494 × 10^-3 × mm²/s was associated with a significantly worse prognosis (P = .006).

CONCLUSIONS

Lower ADC values could predict tumor progression in postoperative chordomas.

The effect of femoral bone tunnel configuration on tendon-bone healing in an anterior cruciate ligament reconstruction: An animal study

Objectives

To compare the effect of femoral bone tunnel configuration on tendon-bone healing in an anterior cruciate ligament (ACL) reconstruction animal model.

Methods

Anterior cruciate ligament reconstruction using the plantaris tendon as graft material was performed on both knees of 24 rabbits (48 knees) to mimic ACL reconstruction by two different suspensory fixation devices for graft fixation. For the adjustable fixation device model (Socket group; group S), a 5 mm deep socket was created in the lateral femoral condyle (LFC) of the right knee. For the fixed-loop model (Tunnel group; group T), a femoral tunnel penetrating the LFC was created in the left knee. Animals were sacrificed at four and eight weeks after surgery for histological evaluation and biomechanical testing.

Results

Histologically, both groups showed a mixture of direct and indirect healing patterns at four weeks, whereas only indirect healing patterns were observed in both groups at eight weeks. No significant histological differences were seen between the two groups at four and eight weeks in the roof zone (four weeks, S: mean 4.8 sd 1.7, T: mean 4.5 sd 0.5, p = 0.14; eight weeks, S: mean 5.8 sd 0.8, T: mean 4.8 sd 1.8, p = 0.88, Mann-Whitney U test) or side zone (four weeks, S: mean 5.0 sd 1.2, T: mean 4.8 sd 0.4, p = 0.43; eight weeks, S: mean 5.3 sd 0.8,T: mean 5.5 sd 0.8, p = 0.61, Mann-Whitney U test) . Similarly, no significant difference was seen in the maximum failure load between group S and group T at four (15.6 sd 9.0N and 13.1 sd 5.6N) or eight weeks (12.6 sd 3.6N and 17.1 sd 6.4N, respectively).

Conclusion

Regardless of bone tunnel configuration, tendon-bone healing after ACL reconstruction primarily occurred through indirect healing. No significant histological or mechanical differences were observed between adjustable and fixed-loop femoral cortical suspension methods.

Cite this article: Y. Sato, R. Akagi, Y. Akatsu, Y. Matsuura, S. Takahashi, S. Yamaguchi, T. Enomoto, R. Nakagawa, H. Hoshi, T. Sasaki, S. Kimura, Y. Ogawa, A. Sadamasu, S. Ohtori, T. Sasho. The effect of femoral bone tunnel configuration on tendon-bone healing in an anterior cruciate ligament reconstruction: An animal study. Bone Joint Res 2018;7:327–335. DOI: 10.1302/2046-3758.75.BJR-2017-0238.R2.

Functional characterization of recombinant snake venom rhodocytin: rhodocytin mutant blocks CLEC-2/podoplanin-dependent platelet aggregation and lung metastasis

Essentials We generated recombinant rhodocytin that could aggregate platelets via CLEC-2. Recombinant wild-type rhodocytin formed heterooctamer with four α- and β-subunits. Asp 4 in α-subunit of rhodocytin was required for binding to CLEC-2. Inhibitory mutant of rhodocytin blocked podoplanin-dependent hematogenous metastasis.

SUMMARY

Background Rhodocytin, a disulfide-linked heterodimeric C-type lectin from Calloselasma rhodostoma consisting of α-subunits and β-subunits, induces platelet aggregation through C-type lectin-like receptor 2 (CLEC-2). CLEC-2 is a physiological binding partner of podoplanin (PDPN), which is expressed on some tumor cell types, and is involved in tumor cell-induced platelet aggregation and tumor metastasis. Thus, modified rhodocytin may be a possible source of anti-CLEC-2 drugs for both antiplatelet and antimetastasis therapy. However, its molecular function has not been well characterized, because of the lack of recombinant rhodocytin that induces platelet aggregation. Objective To produce recombinant rhodocytin, in order to verify its function with mutagenesis, and to develop an anti-CLEC-2 drug based on the findings. Methods We used Chinese hamster ovary cells to express recombinant rhodocytin (wild-type [WT] and mutant), which was analyzed for induction/inhibition of platelet aggregation with light transmission aggregometry, the formation of multimers with blue native PAGE, and binding to CLEC-2 with flow cytometry. Finally, we investigated whether mutant rhodocytin could suppress PDPN-induced metastasis in an experimental lung metastasis mouse model. Results Functional WT] rhodocytin (αWTβWT) was obtained by coexpression of both subunits. Asp4 in α-subunits of rhodocytin was required for CLEC-2 binding. αWTβWT formed a heterooctamer similarly to native rhodocytin. Moreover, an inhibitory mutant of rhodocytin (αWTβK53A/R56A), forming a heterotetramer, bound to CLEC-2 without inducing platelet aggregation, and blocked CLEC-2-PDPN interaction-dependent platelet aggregation and experimental lung metastasis. Conclusion These findings provide molecular characterization information on rhodocytin, and suggest that mutant rhodocytin could be used as a therapeutic agent to target CLEC-2.

Identification and initial characterization of novel neural immediate early genes possibly differentially contributing to foraging-related learning and memory processes in the honeybee

Despite possessing a limited number of neurones compared to vertebrates, honeybees show remarkable learning and memory performance, an example being 'dance communication'. In this phenomenon, foraging honeybees learn the location of a newly discovered food source and transmit the information to nestmates by symbolic abdomen vibrating behaviour, leading to navigation of nestmates to the new food source. As an initial step toward understanding the detailed molecular mechanisms underlying the sophisticated learning and memory performance of the honeybee, we focused on the neural immediate early genes (IEGs), which are specific genes quickly transcribed after neural activity without de novo protein synthesis. Although these have been reported to play an essential role in learning and memory processes in vertebrates, far fewer studies have been performed in insects in this regard. From RNA-sequencing analysis and subsequent assays, we identified three genes, Src homology 3 (SH3) domain binding kinase, family with sequence similarity 46 and GB47136, as novel neural IEGs in the honeybee. Foragers and/or orientating bees, which fly around their hives to memorize the positional information, showed induced expression of these IEGs in the mushroom body, a higher-order centre essential for learning and memory, indicating a possible role for the novel IEGs in foraging-related learning and memory processes in the honeybee.

A genome-wide association study identifies two novel susceptibility loci and trans population polygenicity associated with bipolar disorder

Genome-wide association studies (GWASs) have identified several susceptibility loci for bipolar disorder (BD) and shown that the genetic architecture of BD can be explained by polygenicity, with numerous variants contributing to BD. In the present GWAS (Phase I/II), which included 2964 BD and 61 887 control subjects from the Japanese population, we detected a novel susceptibility locus at 11q12.2 (rs28456, P=6.4 × 10-9), a region known to contain regulatory genes for plasma lipid levels (FADS1/2/3). A subsequent meta-analysis of Phase I/II and the Psychiatric GWAS Consortium for BD (PGC-BD) identified another novel BD gene, NFIX (Pbest=5.8 × 10-10), and supported three regions previously implicated in BD susceptibility: MAD1L1 (Pbest=1.9 × 10-9), TRANK1 (Pbest=2.1 × 10-9) and ODZ4 (Pbest=3.3 × 10-9). Polygenicity of BD within Japanese and trans-European-Japanese populations was assessed with risk profile score analysis. We detected higher scores in BD cases both within (Phase I/II) and across populations (Phase I/II and PGC-BD). These were defined by (1) Phase II as discovery and Phase I as target, or vice versa (for 'within Japanese comparisons', Pbest~10-29, R2~2%), and (2) European PGC-BD as discovery and Japanese BD (Phase I/II) as target (for 'trans-European-Japanese comparison,' Pbest~10-13, R2~0.27%). This 'trans population' effect was supported by estimation of the genetic correlation using the effect size based on each population (liability estimates~0.7). These results indicate that (1) two novel and three previously implicated loci are significantly associated with BD and that (2) BD 'risk' effect are shared between Japanese and European populations.

Quantum-disordered state of magnetic and electric dipoles in an organic Mott system

Strongly enhanced quantum fluctuations often lead to a rich variety of quantum-disordered states. Developing approaches to enhance quantum fluctuations may open paths to realize even more fascinating quantum states. Here, we demonstrate that a coupling of localized spins with the zero-point motion of hydrogen atoms, that is, proton fluctuations in a hydrogen-bonded organic Mott insulator provides a different class of quantum spin liquids (QSLs). We find that divergent dielectric behavior associated with the approach to hydrogen-bond order is suppressed by the quantum proton fluctuations, resulting in a quantum paraelectric (QPE) state. Furthermore, our thermal-transport measurements reveal that a QSL state with gapless spin excitations rapidly emerges upon entering the QPE state. These findings indicate that the quantum proton fluctuations give rise to a QSL—a quantum-disordered state of magnetic and electric dipoles—through the coupling between the electron and proton degrees of freedom.

The organic material κ-H₃(Cat-EDT-TTF)₂ has been suggested to exhibit a quantum spin liquid phase in which quantum fluctuations prevent the formation of magnetic order. Here, the authors show that this may be a result of fluctuations of hydrogen atoms, rather than more conventional geometric frustration.

Internal Fixation of Only the Distal End in a Bipolar Segmental Clavicle Fracture: A Case Report

Bipolar segmental clavicle fractures are simultaneous clavicle fractures of both proximal and distal ends. Few case reports describing these fractures have been published, and the management of these injuries have remained controversial. Non-operative treatment is likely to result in poor shoulder function due to the instability of the fracture in patients with high physical demands. In contrast, surgical treatment with fixation of both proximal and distal ends of the clavicle possibly may cause life-threatening complications. We present a 74-year old female farmer who had injured her left shoulder and was diagnosed with a bipolar segmental clavicle fracture. Taking the fracture mechanism into consideration, we surgically treated only the distal end of the clavicle fracture with a locking plate. The proximal end of the clavicle fracture was treated without surgical intervention. Both fracture sites achieved bony union after four months and she returned to her activities as a farmer. Quick DASH score was 5.0 with excellent results at three years after operation.