Return-to-Work Screening by Linear Discriminant Analysis of Heart Rate Variability Indices in Depressed Subjects.

Using a linear discriminant analysis of heart rate variability (HRV) indices, the present study sought to verify the usefulness of autonomic measurement in major depressive disorder (MDD) patients by assessing the feasibility of their return to work after sick leave. When reinstatement was scheduled, patients' HRV was measured using a wearable electrocardiogram device. The outcome of the reinstatement was evaluated at one month after returning to work. HRV indices including high- and low-frequency components were calculated in three conditions within a session: initial rest, mental task, and rest after task. A linear discriminant function was made using the HRV indices of 30 MDD patients from our previous study to effectively discriminate the successful reinstatement from the unsuccessful reinstatement; this was then tested on 52 patients who participated in the present study. The discriminant function showed that the sensitivity and specificity in discriminating successful from unsuccessful returns were 95.8% and 35.7%, respectively. Sensitivity is high, indicating that normal HRV is required for a successful return, and that the discriminant analysis of HRV indices is useful for return-to-work screening in MDD patients. On the other hand, specificity is low, suggesting that other factors may also affect the outcome of reinstatement.

Usefulness of heart rate variability indices in assessing the risk of an unsuccessful return to work after sick leave in depressed patients.

AIM: The present study aimed to examine whether heart rate variability (HRV) indices in depressed patients measured at return to work after sick leave are related to the outcome of reinstatement. METHODS: This study included 30 workers who took a leave of absence due to major depressive disorder. HRV was measured twice, once when participants left work and another when they returned to work. One month after returning to work, 19 participants continued their original work (successful return group), while 11 failed to perform their original work (unsuccessful return group). HRV indices including high- and low-frequency components (HF and LF) were calculated in three conditions within a session lasting for about 5 minutes, initial rest (Rest), mental task (Task), and rest after task (After), and were compared between the two participant groups. Psychological states were evaluated using Self-rating Depression Scale and State-Trait Anxiety Inventory. RESULTS: No significant differences were observed in the HRV indices on leaving work between groups. On returning to work, the "unsuccessful return group" exhibited lower HF Rest score, higher HF Task/Rest ratio, and higher LF/HF Rest score than the "successful return group." Psychological scores improved in both groups. CONCLUSION: These results indicate that autonomic dysregulations revealed by HRV measurement at return to work after a leave of absence in MDD patients were related to the outcome of reinstatement and can serve as useful information for the assessment of the risk of unsuccessful return.

Age-related alteration in the distribution of methylglyoxal and its metabolic enzymes in the mouse brain.

Methylglyoxal (MG) is an α-dicarbonyl compound that is naturally produced in vivo through glucose metabolism. In general, MG is metabolized by the glyoxalase 1(GLO1)/GLO2 system and aldose reductase (AR); however, excessive MG can react with proteins and nucleic acids to induce the accumulation of advanced glycation end products (AGEs). Recently, the accumulation of AGEs in the brain has been presumed to be related to neurodegenerative diseases such as Parkinson's and Alzheimer's disease, respectively. Research investigating the role of AGEs in such diseases is ongoing. However, the changes in MG concentration that occur in the brain during healthy ageing remain unclear. Therefore, we performed fractionation of the brains of aged and young mice, measured the MG concentration in each part of the brain, and then examined the distribution. We also investigated the expression levels of GLO1 and AR, the main metabolizing enzymes of MG, in various brain regions, across age groups. We show that MG concentration varies among different regions of the brain, and that MG concentration in aged mice is significantly lower than that in young mice across all regions of the brain, except the brain stem. In addition, although the expression level of the GLO1 protein in the brain did not change with ageing, the expression level of AR was higher in aged than in young mice. Moreover, although a significant positive correlation was observed between GLO1 expression and MG concentration in the brains of young mice, no significant correlations were observed in the brains of aged mice. Meanwhile, the production of protein carbonyls and the accumulation of AGEs were not observed in the brains of aged mice. These results suggest that the accumulation of MG in the brain, along with the carbonyl stress are suppressed and regionally controlled during healthy ageing. This finding is useful as the foundation for further studies to investigate the role and toxicity of MG in various age-related disease conditions.

The tendinous septum of the semispinalis capitis muscle spatially separates the dorsal ramus between C3 and C4.

Local anesthetic injection into the medial head of the semispinalis capitis muscle can anesthetize the greater occipital nerve (GON) and third occipital nerve (TON) simultaneously (greater and third occipital nerve block: GTO block). Alternatively, inter-semispinal plane (ISP) block can anesthetize the dorsal rami of the cervical spinal nerves from C4 to T4. The GON, TON, and the dorsal rami of the inferior level cannot be blocked with a single injection. To elucidate this phenomenon from an anatomical standpoint, we performed an ISP block either alone or with a GTO block using water-based acrylic dye in three thiel-embalmed cadavers. Both dyes were clearly separated by the tendinous septum running obliquely inside the semispinalis capitis muscle (SCA). The tendinous septum of the SCA may have a relatively strong connection with the dorsal edge of the semispinalis cervicis muscle, and this structure may stem the injectate spread. Therefore, the GON and TON, running through the medial head of the SCA, and the dorsal rami of the inferior level are spatially separated by the tendinous septum, and cannot be blocked with a single injection.

Visualization of injectate spread of intercostal nerve block: a cadaveric study.

INTRODUCTION: Intercostal nerve block and neurolysis are widely used procedures, but their injectate spread has not been well understood. Previous studies have reported unexpected outcomes (paravertebral or epidural anesthesia) and spinal cord injury after intercostal nerve block and neurolysis. To investigate a possible mechanism for these complications, we aimed to visualize the flow of liquid injected near the intercostal nerve, using cadavers. METHODS: We performed a simulated intercostal nerve block study using two Thiel-embalmed cadavers. Dye was injected into the interfascial plane between the internal and innermost intercostal muscles under ultrasound guidance (blue, 10 ml) or under direct vision (green, 5 ml). RESULTS: Dye leakage began with injection of only 0.5-2 ml and occurred between the innermost intercostal muscle fibers. The dye injected around the intercostal nerve penetrated into the extrapleural space and reached the paravertebral space. CONCLUSIONS: Injectate placed around the intercostal nerve easily penetrate the extrapleural space and reach the paravertebral space. Intercostal nerve block or neurolysis has a risk of impairing at least the sympathetic chain and conceivably affecting the central nervous system.

Anatomical basis for simultaneous block of greater and third occipital nerves, with an ultrasound-guided technique.

PURPOSE: In some headache disorders, for which the greater occipital nerve block is partly effective, the third occipital nerve is also suggested to be involved. We aimed to establish a simple technique for simultaneously blocking the greater and third occipital nerves. METHODS: We performed a detailed examination of dorsal neck anatomy in 33 formalin-fixed cadavers, and deduced two candidate target points for blocking both the greater and third occipital nerves. These target points were tested on three Thiel-fixed cadavers. We performed ultrasound-guided dye injections into these points, examined the results by dissection, and selected the most suitable injection point. Finally, this target point was tested in three healthy volunteers. We injected 4 ml of local anesthetic and 1 ml of radiopaque material at the selected point, guided with a standard ultrasound system. Then, the pattern of local anesthetic distribution was imaged with computed tomography. RESULTS: We deduced that the most suitable injection point was the medial head of the semispinalis capitis muscle at the C1 level of the cervical vertebra. Both nerves entered this muscle, in close proximity, with little individual variation. In healthy volunteers, an anesthetic injected was confined to the muscle and induced anesthesia in the skin areas innervated by both nerves. CONCLUSIONS: The medial head of the semispinalis capitis muscle is a suitable landmark for blocking the greater and third occipital nerves simultaneously, by which occipital nerve involvement in various headache disorders may be rapidly examined and treated.

Characterization of the complex formation of 1,6-anhydro-ß-maltose and potassium ions using NMR spectroscopy and single-crystal X-ray crystallography.

The formation of a complex between 1,6-anhydro-ß-maltose and potassium ions was characterized using (1)H, (13)C and (39)K NMR spectroscopy and single-crystal X-ray crystallography. In the NMR study, the spin-lattice relaxation times (T(1)) of C1, C3, C5, C6, and C5' significantly decreased in the presence of potassium ions, and (39)K-T(1) also decreased in the presence of 1,6-anhydro-ß-maltose, indicating complex formation. In a crystal, both 8- and 9-coordination structures, corresponding to the distorted capped pentagonal bipyramidal structure and the capped hexagonal bipyramidal structure, respectively, were identified. A potassium ion was positioned in the center of each bipyramidal structure.

An anatomical basis for blocking of the deep cervical plexus and cervical sympathetic tract using an ultrasound-guided technique.

BACKGROUND: A selective blocking method for the cervical plexus and the cervical sympathetic trunk has not yet been established. METHODS: We performed a detailed examination of the neck anatomy using 28 cadavers. The pattern of local anesthetic distribution after injection in 2 healthy volunteers was imaged using computed tomographic scan. RESULTS: The deep cervical plexus was located in the groove between the longus capitis and scalenus medius muscles. The cervical sympathetic trunk was located on the anteromedial surface of the longus capitis. Although anesthetic injected into the longus capitis was confined to the muscle, it infiltrated into neighboring structures including the C2 to C5 roots and sympathetic trunk. CONCLUSIONS: The longus capitis muscle is a suitable landmark for blocking the cervical plexus and trunk.

Recovery of psychomotor function after propofol sedation is prolonged in the elderly.

PURPOSE: To assess the effects of age on recovery of psychomotor function for propofol sedation during spinal anesthesia. METHODS: Propofol was continuously infused during surgery and spinal anesthesia in 15 elderly patients (65-85 yr-old) and 15 younger patients (20-50 yr-old). Infusion rates were adjusted to maintain an appropriate level of sedation using the bispectral index (range 60-70). The sedative infusion was discontinued at the end of surgery. The early recovery times from the end of propofol infusion to opening of eyes on command, sustaining a hand grip, and recall of name were noted. Psychomotor function, as measured by the Trieger's dot test, was evaluated before anesthesia and 30, 60, 90, 120 min after the end of propofol infusion. RESULTS: The duration of anesthesia was 142 +/- 55 min and 134 +/- 61 min in the elderly and younger patients, respectively. No differences were observed in early recovery times between elderly and younger patients (opened their eyes on command, 6.3 +/- 4.0 min and 5.2 +/- 2.6 min; sustained a hand grip, 7.2 +/- 3.9 min and 6.1 +/- 3.5 min and recalled their name, 8.0 +/- 4.5 min and 6.5 +/- 3.8 min, P > 0.05 ). The recovery of psychomotor function in the elderly took longer compared with the younger patients, and psychomotor function in the elderly recovered at 120 min after the end of propofol infusion. CONCLUSION: Early recovery times following propofol sedation is similar between elderly and younger patients, but recovery of psychomotor function in the elderly is delayed compared with younger patients.