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Objective: Of necessity, naval crews live in confined spaces when on board warships, which may lead to decreased bone mass and to subsequent bone fractures. Therefore, we investigated the bone mass of crew members and the relationship between bone mass and lifestyle factors. Methods: We selected 1510 crew members of the Japan Maritime Self-Defense Force. All were men between 18 and 58 years of age. We measured their bone mass by applying quantitative ultrasound (QUS) to the calcaneus. In addition, we reviewed daily milk consumption, levels of physical exercise, type of on-board job, fracture history, nutritional supplementation habits, and body mass index (BMI). Results: Bone mass values were lower than the published mean values for Japanese men across the twenties to forties age groups. Conclusions: The factors found to be related to bone mass in this study were age, type of on-board job, exercise level, and milk consumption. Lifestyle factors are usually within our control. Our data suggest that moderate levels of regular exercise and milk consumption may maintain bone mass. [ABSTRACT FROM AUTHOR]

Tidal response methods are usually used to estimate the hydraulic parameters of coastal aquifers. In this study an analytical model for aquifer tidal response was used. An existing analytical solution for tidal response of groundwater levels was extended to evaluate a subsurface barrier wall to prevent saltwater penetration in a coastal aquifer. A field feasibility study was conducted at the Komesu Dam, Japan. Groundwater levels were observed at pairs of sites on the seaward and reservoir sides of the wall. Groundwater-level time series data collected from a reservoir-side site near a horizontal hollow pipe penetrating the wall contained a visible sinusoidal tidal component, whereas data from another reservoir-side site did not. Analysis of these observations on the groundwater tidal response derived hydraulic parameters of the barrier wall between the paired observation sites. Although the parameters derived by the used simple formulas seem only approximate or apparent, the difference of the results for the two pairs indicated that the extended tidal response method can be useful for evaluation of the barrier function of the wall., (© 2022 National Ground Water Association.)

Ischemic neuropathy is common in subjects with critical limb ischemia, frequently causing chronic neuropathic pain. However, neuropathic pain caused by ischemia is hard to control despite the restoration of an adequate blood flow. Here, we used a rat model of ischemic-reperfusion nerve injury (IRI) to investigate possible effects of hepatocyte growth factor (HGF) against ischemic neuropathy. Hemagglutinating virus of Japan (HVJ) liposomes containing plasmids encoded with HGF was delivered into the peripheral nervous system by retrograde axonal transport following its repeated injections into the tibialis anterior muscle in the right hindlimb. First HGF gene transfer was done immediately after IRI, and repeated at 1, 2 and 3 weeks later. Rats with IRI exhibited pronounced mechanical allodynia and thermal hyperalgesia, decreased blood flow and skin temperature, and lowered thresholds of plantar stimuli in the hind paw. These were all significantly improved by HGF gene transfer, as also were sciatic nerve conduction velocity and muscle action potential amplitudes. Histologically, HGF gene transfer resulted in a significant increase of endoneurial microvessels in sciatic and tibial nerves and promoted nerve regeneration which were confirmed by morphometric analysis. Neovascularization was observed in the contralateral side of peripheral nerves as well. In addition, IRI elevated mRNA levels of P2X3 and P2Y1 receptors, and transient receptor potential vanilloid receptor subtype 1 (TRPV1) in sciatic nerves, dorsal root ganglia and spinal cord, and these elevated levels were inhibited by HGF gene transfer. In conclusion, HGF gene transfer is a potent candidate for treatment of acute ischemic neuropathy caused by reperfusion injury, because of robust angiogenesis and enhanced nerve regeneration., Competing Interests: The authors have declared that no competing interest exists.

Background: Shoulder rotational muscles act as dynamic stabilizers of the glenohumeral joint, and the recovery of muscle strength plays an important role in stabilizing the joint during postoperative rehabilitation. However, temporal changes in muscle strength after arthroscopic Bankart repair have not been clarified., Purpose: To better understand the temporal recovery of shoulder rotational muscle strength after arthroscopic Bankart repair., Study Design: Case series; Level of evidence, 4., Methods: Isokinetic concentric shoulder rotational muscle strength was evaluated in 50 patients who were diagnosed with recurrent dislocations of the glenohumeral joint and treated with arthroscopic Bankart repair., Results: The mean peak torque/weight and total work were reduced significantly at 1.5 months after surgery ( P < .0001) and returned to preoperative levels by 6 months for external rotation and 4.5 months for internal rotation. The contralateral peak torque ratios reached preoperative levels by 6 months after surgery. The ipsilateral peak torque ratios were reduced between 1.5 and 3 months after surgery and returned to preoperative levels at 6 months for external rotation and 4.5 months for internal rotation., Conclusion: Isokinetic shoulder rotational muscle strength after arthroscopic Bankart repair recovered to preoperative levels by 6 months for external rotation and 4.5 months for internal rotation., Competing Interests: The authors declared that they have no conflicts of interest in the authorship and publication of this contribution.

Background: The long-term effect of repetitive trauma by military parachuting on the lumbar spine is not well investigated. Therefore, the purpose of this study was to examine the development of lumbar degenerative changes during a 30-year follow-up in Japanese Ground Self Defense Forces (JGSDF) parachute infantry soldiers with normal lumbar radiographs at entry by comparison with those with non-parachute infantry soldiers., Methods: 79 non-parachutists and 65 parachutists were included for radiological examination and questionnaires for low back pain (LBP). All subjects were non-commissioned officers with similar socioeconomic status and life styles. The number of parachuting descent during the 30-year in the parachute group ranged from 208 to 630, with an average of 322., Results: The mean age of the subjects was 18.3±0.5 years at entry and 48.5±0.3 years at follow-up. LBP had been experienced by 37% in the non-parachute group and 25% in the parachute group with no significant difference. The nature of their LBP was judged as mild. The prevalence rate of degenerative changes was similar in both groups. Disc space narrowing was detected 37 subjects (47%) in non-parachute group an 23 subjects (35%) in parachute group without significant difference. Vertebral osteophytes were detected in 52 subjects (67%) in non-parachute group and 47 subjects (72%) in parachute group without significant difference., Conclusions: This study did not identify any significant differences in the development of lumbar degenerative changes between the parachutists and non-parachutists over a 30-year follow-up, suggesting that military parachuting itself does not accelerate the development of intervertebral disc degeneration. Further studies are needed using large cohorts assessed by MRI as well as plain X-ray., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Glucagon-like peptide-1 (GLP-1) is glucose-dependent insulinotropic hormone secreted from enteroendocrine L cells. Its long-acting analogue, exendin-4, is equipotent to GLP-1 and is used to treat type 2 diabetes mellitus. In addition, exendin-4 has effects on the central and peripheral nervous system. In this study, we administered repeated intraperitoneal (i.p.) injections of exendin-4 to examine whether exendin-4 is able to facilitate the recovery after the crush nerve injury. Exendin-4 injection was started immediately after crush injury and was repeated every day for subsequent 14 days. Rats subjected to sciatic nerve crush exhibited marked functional loss, electrophysiological dysfunction, and atrophy of the tibialis anterior muscle (TA). All these changes, except for the atrophy of TA, were improved significantly by the administration of exendin-4. Functional, electrophysiological, and morphological parameters indicated significant enhancement of nerve regeneration 4 weeks after nerve crush. These results suggest that exendin-4 is feasible for clinical application to treat peripheral nerve injury.

A species of stinging nettle, Urtica ferox, is indigenous to New Zealand and has caused deaths in animals and humans. We previously reported a human case of acute polyneuropathy due to U. ferox stings. We developed an experimental animal model of U. ferox toxin neuropathy to determine its neurophysiological and pathological characteristics. Male Wistar rats received either normal saline or fluid from U. ferox trichomes by injection into the epineurium of the left sciatic nerve. Neurophysiological and histological studies were carried out 5, 14 and 28 days after administration. Toxin-injected rats developed paresis of the left leg by 14 days with recovery by 28 days. Compound muscle action potentials amplitudes on the left side of toxin-administered rats at day 14 were significantly reduced compared to the right uninjected side. Toxin-injected nerves at days 5 and 14 showed a reduction in the number of myelinated fibres compared to the saline-injected nerves and frequency distributions of myelinated fibres showed a shift to smaller fibres. U. ferox neurotoxin thus produced a transient neuropathy in rat peripheral nerves with neurophysiological and pathological features suggestive of axonopathy. The identity and mechanism of action of the toxin responsible for neuropathy are uncertain., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Background: Gene transduction has been considered advantageous for the sustained delivery of proteins to specific target tissues. However, in the case of hard tissues, such as bone, local gene delivery remains problematic owing to anatomical accessibility limitations of the target sites., Methodology/principal Findings: Here, we evaluated the feasibility of exogenous gene transduction in the interior of bone via axonal transport following intramuscular administration of a nonviral vector. A high expression level of the transduced gene was achieved in the tibia ipsilateral to the injected tibialis anterior muscle, as well as in the ipsilateral sciatic nerve and dorsal root ganglia. In sciatic transection rats, the gene expression level was significantly lowered in bone., Conclusions/significance: These results suggest that axonal transport is critical for gene transduction. Our study may provide a basis for developing therapeutic methods for efficient gene delivery into hard tissues.

Peripheral nerve injury occasionally causes chronic neuropathic pain with hyperalgesia and allodynia. However, its treatment is difficult. Here, we used a chronic constriction injury (CCI) model in rats to investigate the effects on experimental neuropathic pain of the human hepatocyte growth factor (HGF) gene delivered into the nervous system by retrograde axonal transport following its repeated intramuscular transfer, using liposomes containing the hemagglutinating virus of Japan (HVJ). CCI (control) rats exhibited marked mechanical allodynia and thermal hyperalgesia, and decreased blood flow in sciatic nerve and hind paw. All these changes were significantly reversed by HGF gene transfer. In the sciatic nerve in HGF-treated rats, the size-frequency distributions for myelinated and unmyelinated axons each showed a rightward shift, the number of myelinated axons >5 microm in diameter was significantly increased, and the mean diameter of unmyelinated axons was significantly increased (versus CCI rats). Levels of P2X3, P2X4, and P2Y1 receptor mRNAs, and of interleukin-6 (IL-6) and activating transcription factor 3 (ATF3) mRNAs, were elevated in the ipsilateral dorsal root ganglia and/or sciatic nerve by CCI, and these levels were decreased by HGF gene transfer. These results may point toward a potential new treatment strategy for chronic neuropathic pain in this model.

We present a 24-year-old man and a 31-year-old woman who complained of persistent back pain with osteoid osteoma of the thoracic spine. Computed tomography (CT) revealed a round sclerotic lesion in the posterior element of the thoracic spine, although their plain radiographs showed no abnormalities except a slight scoliosis. The patients underwent total excision of the tumor via a posterior approach. They are currently asymptomatic with no recurrence of the lesion and have returned to full activity. The thin slice CT is one of the most important diagnostic tools for osteoid osteoma of the spine.

We synthesized 27 GTP analogues with modification or substitution at positions C2, C6, C8 and ribose moiety to investigate their effect on microtubule (Mt) assembly. It was found that C2 and C6 are both functional for the analogues supporting Mt assembly. It was surprising to find that 2-amino- ATP (n2ATP) substantially supports assembly, and that the appearance of the assembled Mts was indistinguishable from those assembled in the standard GTP assembly buffer solution. Furthermore, 2-amino dATP and dGTP are even more potent than GTP in supporting assembly. The substitution of oxo group at C6 with reactive thiol largely reduced the activity of the analogue to support assembly. When free rotation of the glycosidic linkage of GTP was blocked by the introduction of sulfur atom between C8 and C2' of ribose moiety, it resulted in total suppression of assembly. Purine nucleoside triphosphate was found to support assembly better than GTP, and even more efficient was 2-amino purine nucleoside triphosphate. Interestingly, their deoxy-type analogues were totally inhibitory. Although 2-amino 8-hydroxy ATP and other analogues supported assembly much better than did GTP, their diphosphate analogues were totally incapable of supporting assembly. Finally, bulky fluorescent probes were introduced at C3' of ribose moiety (Mant-8-Br-GTP or Mant-GTP) to visualize the fluorescent signal in assembled Mts. Even in this case, the number of most protofilaments was found to be 14, consistent with that found in Mts assembled in GTP standard buffer solution.

More than 20 base-modified analogues of guanosine 5'-triphosphate including 2'-deoxyguanosine derivatives were synthesized and examined their effect on tubulin polymerization into microtubules (Mts). Among those, 2,6-diamino-8-oxopurineriboside 5'-triphosphate (1d), 2,6-diamino-2'-deoxypurineriboside 5'-tri phosphate (1b) and 8-bromoguanosine 5'-tri phosphate (1g) were shown to have remarkable effect to promote microtubule assembly.