Influence of Pedicle Screw Insertion Depth on Posterior Lumbar Interbody Fusion: Radiological Significance of Deeper Screw Placement

STUDY DESIGN

Retrospective case series.

OBJECTIVES

To investigate the influence of screw size on achieving bone fusion in posterior lumbar interbody fusion (PLIF).

METHODS

In total, 137 consecutive patients with L4 degenerative spondylolisthesis who underwent single-level PLIF at L4-L5 were evaluated. Factors investigated for their contribution to bone fusion included: 1) age, 2) sex, 3) body mass index, 4) bone mineral density, 5) intervertebral mobility, 6) screw diameter, 7) screw length, 8) screw fitness in the pedicle (%fill), 9) screw depth in the vertebra (%depth), 10) screw angle, 11) facetectomy, 12) crosslink connector, and 13) cage material.

RESULTS

Bone fusion was confirmed in 88.2% of patients. The comparison between fusion (+) and fusion (-) groups showed no significant differences in screw size. The %fill and %length were significantly greater in the fusion (+) group than in the fusion (-) group (%fill: 58.5% ± 7.5% vs 52.3% ± 7.3%, respectively, P = .005; %depth: 59.8% ± 9.7% vs 50.3% ± 13.8%, respectively, P = .025). Multivariate logistic regression analysis revealed that %fill (odds ratio [OR]= 1.11, P = .025) and %depth (OR = 1.09, P = .003) were significant independent factors affecting bone fusion. Receiver operating characteristic curve analyses identified a %fill of 60.0% and a %depth of 54.2% as optimal cutoff values for achieving bone fusion.

CONCLUSIONS

Screw size should be determined based on the screw fitness in the pedicle (%fill > 60%) and screw insertion depth in the vertebral body (%depth > 54.2%) according to individual vertebral anatomy in L4-L5 PLIF.

Does the degree of preoperative gait disturbance remain after tumor resection in patients with intradural extramedullary spinal cord tumors?

STUDY DESIGN

Retrospective comparative study.

OBJECTIVE

This study aimed to determine whether the degree of preoperative gait disturbance remains following surgical resection in patients with intradural extramedullary spinal cord tumors (IDEMSCTs), and to investigate any factors that may influence poor improvement in postoperative gait disturbance.

SETTING

The single institution in Japan.

METHODS

In total, 78 IDEMSCTs patients who required surgical excision between 2010 and 2019 were included. According to the degree of preoperative gait disturbance using modified McCormick scale (MMCS) grade, they were divided into the Mild and Severe groups. The mean postoperative follow-up period was 50.7 ± 17.9 months. Data on demographic and surgical characteristics were compared between the two groups.

RESULTS

There was no significant difference in terms of age at surgery, sex, tumor size, surgical time, estimated blood loss, tumor histopathology, and postoperative follow-up period between the Mild and Severe groups. At the final follow-up, 84.6% of IDEMSCTs patients were able to walk without support. Gait disturbance improved after surgery in most of the patients with preoperative MMCS grades II-IV, but remained in approximately half of patients with preoperative MMCS grade V. Age at surgery was correlated with poor improvement in postoperative gait disturbance in the Severe group.

CONCLUSIONS

Regardless of the degree of preoperative gait disturbance, it improved after tumor resection in most of the IDEMSCTs patients. However, in the preoperative MMCS grade III-V cases, older age at surgery would be an important factor associated with poor improvement in postoperative gait disturbance.

A shift of brain network hub after spinal cord injury

Background

Spinal cord injury (SCI) causes severe sequelae and significant social loss, depending on the extent of the damage. Most previous studies have focused on the pathology of the spinal cord to develop treatments for SCI. However, it is now known that the brain, which is not directly damaged, also undergoes morphological changes after spinal cord injury, which could affect natural recovery and treatment. In recent years, magnetic resonance imaging (MRI) has been developed to analyze functional changes in the brain. Resting-state functional MRI (rsfMRI), which captures brain activity at rest, can calculate functional connections between brain areas and identify central hubs by network analysis.

Purpose

We aim to investigate functional connectivity in the brain using rsfMRI after SCI and to determine how brain-network main hubs change over time.

Methods

We evaluated rsfMRI in 10 mice of the contusional SCI model and calculated connectivity using graph theory. We evaluated "centrality," a representative parameter of network analysis. The subtype of centrality was degree centrality, which indicates the hub function of a single area. The five times of rsfMRI were performed in each individual mouse: before injury and at 1, 3, 7, and 14 weeks post-injury.

Results

Before the injury, the degree centralities of the primary and secondary motor cortex were high, suggesting that these motor cortices served as main hubs for motor function. After SCI, the hub function of the motor cortices decreased by 14 weeks. In contrast, hub function in the external capsule and the putamen comparatively increased with time after injury, suggesting that the extrapyramidal/subcortical system, which runs the ventral side of the spinal cord and remains after injury in this model, becomes dominant.

Conclusion

We demonstrated the shift of the brain network hub after SCI. The results of this study provide basic information for understanding brain network changes after SCI and would be useful for treatment selection and evaluation of its efficacy in SCI patients.

Effects of Bone Cross-Link Bridging on Fracture Mechanism and Surgical Outcomes in Elderly Patients with Spine Fractures

STUDY DESIGN

This study adopted a cross-sectional study design.

PURPOSE

This study was designed to investigate the effects of bone cross-link bridging on fracture mechanism and surgical outcomes in vertebral fractures using the maximum number of vertebral bodies with bony bridges between adjacent vertebrae without interruption (maxVB).

OVERVIEW OF LITERATURE

The complex interplay of bone density and bone bridging in the elderly can complicate vertebral fractures, necessitating a better understanding of fracture mechanics.

METHODS

We examined 242 patients (age >60 years) who underwent surgery for thoracic to lumbar spine fractures from 2010 to 2020. Subsequently, the maxVB was classified into three groups: maxVB (0), maxVB (2-8), and maxVB (9-18), and parameters, including fracture morphology (new Association of Osteosynthesis classification), fracture level, and neurological deficits were compared. In a sub-analysis, 146 patients with thoracolumbar spine fractures were classified into the three aforementioned groups based on the maxVB and compared to determine the optimal operative technique and evaluate surgical outcomes.

RESULTS

Regarding the fracture morphology, the maxVB (0) group had more A3 and A4 fractures, whereas the maxVB (2-8) group had less A4 and more B1 and B2 fractures. The maxVB (9-18) group exhibited an increased frequency of B3 and C fractures. Regarding the fracture level, the maxVB (0) group tended to have more fractures in the thoracolumbar transition region. Furthermore, the maxVB (2-8) group had a higher fracture frequency in the lumbar spine area, whereas the maxVB (9-18) group had a higher fracture frequency in the thoracic spine area than the maxVB (0) group. The maxVB (9-18) group had fewer preoperative neurological deficits but a higher reoperation rate and postoperative mortality than the other groups.

CONCLUSIONS

The maxVB was identified as a factor influencing fracture level, fracture type, and preoperative neurological deficits. Thus, understanding the maxVB could help elucidate fracture mechanics and assist in perioperative patient management.

Normal pressure hydrocephalus due to an iatrogenic giant lumbar pseudomeningocele after posterior lumbar interbody fusion: illustrative case

BACKGROUND

Iatrogenic pseudomeningocele incidence after lumbar surgery is 0.068%–2%, and most lumbar pseudomeningoceles are smaller than 5 cm; however, in rare cases, “giant” pseudomeningoceles greater than 8 cm in size may develop. Normal pressure hydrocephalus (NPH) is another rare condition in which the ventricles expand despite the presence of normal intracranial pressure. To date, pseudomeningocele associated with NPH has not been reported.

OBSERVATIONS

An 80-year-old woman underwent L3–5 laminectomy and posterior lumbar interbody fusion, and her symptoms improved after surgery. However, dementia appeared 1 month after surgery. Repeated brain computed tomography showed ventricular enlargement, and lumbar magnetic resonance imaging showed a long pseudomeningocele in the subcutaneous tissues at the L4 level. Here, the authors report a rare case of an iatrogenic giant pseudomeningocele accompanied by NPH after lumbar surgery. The symptoms of NPH in the present case occurred after spinal surgery and recovered after dural repair surgery, indicating that the changes in cerebrospinal fluid circulation and/or pressure due to pseudomeningoceles may cause NPH.

LESSONS

The prevention of dural tears through precise surgical technique and primary repair of dural tears are the best approaches to prevent pseudomeningocele incidence and subsequent events.

Neurorehabilitation using a voluntary driven exoskeletal robot improves trunk function in patients with chronic spinal cord injury: a single-arm study

Body weight-supported treadmill training with the voluntary driven exoskeleton (VDE-BWSTT) has been shown to improve the gait function of patients with chronic spinal cord injury. However, little is known whether VDE-BWSTT can effectively improve the trunk function of patients with chronic spinal cord injury. In this open-label, single-arm study, nine patients with chronic spinal cord injury at the cervical or thoracic level (six males and three females, aged 37.8 ± 15.6 years, and time since injury 51.1 ± 31.8 months) who underwent outpatient VDE-BWSTT training program at Keio University Hospital, Japan from September 2017 to March 2019 were included. All patients underwent twenty 60-minute gait training sessions using VDE. Trunk muscular strength, i.e., the maximum force against which patient could maintain a sitting posture without any support, was evaluated in four directions: anterior, posterior, and lateral (right and left) after 10 and 20 training sessions. After intervention, lateral muscular strength significantly improved. In addition, a significant positive correlation was detected between the change in lateral trunk muscular strength after 20 training sessions relative to baseline and gait speed. The change in trunk muscular strength after 20 training sessions relative to baseline was greatly correlated with patient age. This suggests that older adult patients with chronic spinal cord injury achieved a greater improvement in trunk muscle strength following VDE-BWSTT. All these findings suggest that VDE-BWSTT can improve the trunk function of patients with chronic spinal cord injury and the effect might be greater in older adult patients. The study was approved by the Keio University of Medicine Ethics Committee (IRB No. 20150355-3) on September 26, 2017.

Influence of body weight-supported treadmill training with voluntary-driven exoskeleton on the quality of life of persons with chronic spinal cord injury: a pilot study

The aim of this study was to investigate whether body weight-supported treadmill training with voluntary-driven exoskeleton body weight-supported treadmill training (VDE-BWSTT) improves the quality of life (QOL) of persons with chronic spinal cord injury (SCI). Nineteen individuals with chronic SCI with walking limitation underwent a total of 20 sessions of VDE-BWSTT using the hybrid assistant limb. The QOL was measured using the Short Form-36v2 (SF-36v2) questionnaire at preintervention and postintervention. The Walking Index for SCI-II (WISCI-II), Functional Independence Measure (FIM) motor score, and Neuropathic Pain Symptom Inventory (NPSI) self-questionnaire were also administered/completed. In SF-36v2, the mean values of all subscales in our participants were lower than those in healthy individuals. None of the measures showed significant improvement, even in individuals with some residual walking ability (baseline WISCI-II score of 6 or higher). In the correlation analysis between the baselines WISCI-II, FIM, or NPSI values and the mean SF-36v2 subscale changes throughout the training, the baseline FIM motor score was positively correlated with the mean changes in Role Emotional and Mental Health. In addition, NPSI was negatively correlated with the mean change in Vitality and Mental Health. In our protocol, although VDE-BWSTT did not improve the QOL of persons with chronic SCI, those with higher functional independence or lower pain at preintervention likely improved. Further study with combination of task-specific training or pain-targeting treatment with more patients should be considered to more effectively improve their QOL.

P183 Arterial stiffness was inversely associated with left ventricular diastolic function in indigenous Papuan populations

Background

Age-related increase in systolic pressure is known to be absent in indigenous Papuan populations, partially because of their life-long low-sodium and high-potassium diets.

Purpose

The aim of this study was to investigate the age-related change in left ventricular (LV) systolic and diastolic function and the relationship with arterial hemodynamics among the indigenous Papuan highland people. 

Methods

Indices of arterial hemodynamics were measured using oscillometric brachial cuff-based sphygmomanometer (Mobil-O-Graph). Brachial-ankle pulse wave velocity (baPWV) was measured using a semiautomatic device (form ABI/baPWV). LV systolic and diastolic function was evaluated by 2-dimensional echocardiography and tissue-Doppler imaging using Vivid iq.

Results

A total of 81 native Papuans (median age 42 years, 47% women) were enrolled in this study. None of the subjects took any medicines, particularly antihypertensive drugs. All participants presented in sinus rhythm. With ageing, LV mass index remained unchanged, and LV ejection fraction increased, but mildly reduced (40–50%) in 3 participants. Transmitral E-wave velocity slightly decrease but the change was not significant. Transmitral A-wave velocity markedly increased (ρ=0.60, P < 0.001) and E/A ratio decreased with age (ρ=-0.52, P < 0.001). Age-related change of E-wave deceleration time was not significant. Septal e′ (ρ=-0.60, P < 0.001) and lateral e′ decreased (ρ=-0.53, P < 0.001) and average E/e′ increased with age (ρ=0.44, P < 0.001). Left atrial volume index did not change significantly with age. In multivariate regression analysis, baPWV was independently associated with E/e" ratio both before and after adjustment for age, sex, body mass index, mean arterial pressure, and heart rate; however, indices of wave reflection including augmentation index and reflection magnitude were not associated with E/e′. Only age and heart rate were inversely associated with E/A ratio. 

Conclusion

LV systolic function was preserved in indigenous Papuan populations; however, LV diastolic function decreased with ageing. Age-related arterial stiffening, not wave reflection, was inversely related to LV diastolic function.

Assessing cortical plasticity after spinal cord injury by using resting-state functional magnetic resonance imaging in awake adult mice

Neural connectivity has recently been shown to be altered after spinal cord injury (SCI) not only in the spinal cord but also in the brain. However, to date, no studies have analyzed the functional alterations after SCI in various areas of the cerebral cortex over time. To examine the plasticity of the neural connectivity in the brain after SCI, we performed resting-state functional magnetic resonance imaging (rs-fMRI) in awake adult mice pre- and post-SCI. After a complete thoracic SCI, the functional connectivity between the primary motor (MOp) and primary sensory (SSp) areas was significantly decreased during the chronic phase. In contrast, the connectivity between the MOp and motivation area was increased. Thus, impairments in sensory and motor connections after SCI led to a time-dependent compensatory upregulation of “motor functional motivation”. Moreover, the functional connectivity between the SSp and pain-related areas, such as the caudoputamen (CP) and the anterior cingulate area (ACA), was strengthened during the chronic phase, thus suggesting that rs-fMRI can indicate the presence of neuropathic pain after SCI. Therefore, rs-fMRI is a useful tool for revealing the pathological changes that occur in the brain after SCI.

Investigation of antibody to severe fever with thrombocytopenia syndrome virus (SFTSV) in blood samples donated in a SFTS-endemic area in Japan

The risk of transfusion-transmitted infection (TTI) for severe fever with thrombocytopenia syndrome virus (SFTSV) is a concern because person-to-person transmission resulting from contact with SFTSV-contaminated blood has been reported. To obtain information regarding the risk of TTI-SFTSV, antibody testing was performed for blood samples donated in an severe fever with thrombocytopenia syndrome-endemic area in Japan. No antibody-positive samples were detected among 3990 samples. This finding suggested that there were few cases of SFTSV infection among donors and that the risk of TTI-SFTSV was also estimated low in Japan.

Pretreatment with a γ-Secretase Inhibitor Prevents Tumor-like Overgrowth in Human iPSC-Derived Transplants for Spinal Cord Injury

Neural stem/progenitor cells (NS/PCs) derived from human induced pluripotent stem cells (hiPSCs) are considered to be a promising cell source for cell-based interventions that target CNS disorders. We previously reported that transplanting certain hiPSC-NS/PCs in the spinal cord results in tumor-like overgrowth of hiPSC-NS/PCs and subsequent deterioration of motor function. Remnant immature cells should be removed or induced into more mature cell types to avoid adverse effects of hiPSC-NS/PC transplantation. Because Notch signaling plays a role in maintaining NS/PCs, we evaluated the effects of γ-secretase inhibitor (GSI) and found that pretreating hiPSC-NS/PCs with GSI promoted neuronal differentiation and maturation in vitro, and GSI pretreatment also reduced the overgrowth of transplanted hiPSC-NS/PCs and inhibited the deterioration of motor function in vivo. These results indicate that pretreatment with hiPSC-NS/PCs decreases the proliferative capacity of transplanted hiPSC-NS/PCs, triggers neuronal commitment, and improves the safety of hiPSC-based approaches in regenerative medicine.

Dome-shaped magnetic order competing with high-temperature superconductivity at high pressures in FeSe

The coexistence and competition between superconductivity and electronic orders, such as spin or charge density waves, have been a central issue in high transition-temperature (Tc) superconductors. Unlike other iron-based superconductors, FeSe exhibits nematic ordering without magnetism whose relationship with its superconductivity remains unclear. Moreover, a pressure-induced fourfold increase of Tc has been reported, which poses a profound mystery. Here we report high-pressure magnetotransport measurements in FeSe up to ∼15 GPa, which uncover the dome shape of magnetic phase superseding the nematic order. Above ∼6 GPa the sudden enhancement of superconductivity (Tc≤38.3 K) accompanies a suppression of magnetic order, demonstrating their competing nature with very similar energy scales. Above the magnetic dome, we find anomalous transport properties suggesting a possible pseudogap formation, whereas linear-in-temperature resistivity is observed in the normal states of the high-Tc phase above 6 GPa. The obtained phase diagram highlights unique features of FeSe among iron-based superconductors, but bears some resemblance to that of high-Tc cuprates.

Development of multi-frequency ESR system for high-pressure measurements up to 2.5 GPa

A new piston-cylinder pressure cell for electron spin resonance (ESR) has been developed. The pressure cell consists of a double-layer hybrid-type cylinder with internal components made of the ZrO2-based ceramics. It can generate a pressure of 2 GPa repeatedly and reaches a maximum pressure of around 2.5 GPa. A high-pressure ESR system using a cryogen-free superconducting magnet up 10T has also been developed for this hybrid-type pressure cell. The frequency region is from 50 GHz to 400 GHz. This is the first time a pressure above 2 GPa has been achieved in multi-frequency ESR system using a piston-cylinder pressure cell. We demonstrate its potential by showing the results of the high-pressure ESR of the S=1 system with the single ion anisotropy NiSnCl6·6H2O and the S=1/2 quantum spin system CsCuCl3. We performed ESR measurements of these systems above 2 GPa successfully.

Association between dental status and food diversity among older Japanese

OBJECTIVE

To investigate the relationship of dental status to food diversity among older Japanese.

DESIGN AND SETTING

A community-based cross-sectional study conducted in the town of Tosa, Kochi Prefecture, Japan.

METHODS

The study participants were 252 Japanese (84 men and 168 women, average age 81.2 years) and dentate participants were classified into three groups: 1-9 teeth, 10-19 teeth and 20 or more teeth. Food diversity was assessed as a validated measure of dietary quality using the 11-item Food Diversity Score Kyoto (FDSK-11), which evaluates frequency of consumption of 11 main food groups. Multivariable analysis of the differences in FDSK-11 score ranging from 0 to 11, with a higher score indicating greater food diversity, among the three dental status groups was conducted using general linear models. All the performed analyses were stratified by gender.

RESULTS

There was no association between dental status and food diversity score in models for men. In contrast, women with ≤ 9 teeth and with 10-19 teeth had significantly lower FDSK-11 scores than women with ≥ 20 teeth after adjusting for confounders (p < 0.001 and p = 0.009, respectively). Additionally, there was a trend toward lower scores for FDSK-11 with fewer teeth (p = 0.001).

CONCLUSION

A less varied diet, as indicated by low FDSK-11 score, was observed in female participants with fewer teeth. Tooth loss was associated with poor diet quality among older Japanese women.

Pressure induced superconductivity on the border of magnetic order in MnP

We report the discovery of superconductivity on the border of long-range magnetic order in the itinerant-electron helimagnet MnP via the application of high pressure. Superconductivity with T(sc)≈1  K emerges and exists merely near the critical pressure P(c)≈8  GPa, where the long-range magnetic order just vanishes. The present finding makes MnP the first Mn-based superconductor. The close proximity of superconductivity to a magnetic instability suggests an unconventional pairing mechanism. Moreover, the detailed analysis of the normal-state transport properties evidenced non-Fermi-liquid behavior and the dramatic enhancement of the quasiparticle effective mass near P(c) associated with the magnetic quantum fluctuations.

Pressure-induced valence crossover and novel metamagnetic behavior near the antiferromagnetic quantum phase transition of YbNi_{3}Ga_{9}

We report electrical resistivity, ac magnetic susceptibility, and x-ray absorption spectroscopy measurements of intermediate valence YbNi_{3}Ga_{9} under pressure and magnetic field. We have revealed a characteristic pressure-induced Yb valence crossover within the temperature-pressure phase diagram, and a first-order metamagnetic transition is found below P_{c}∼9  GPa where the system undergoes a pressure-induced antiferromagnetic transition. As a possible origin of the metamagnetic behavior, a critical valence fluctuation emerging near the critical point of the first-order valence transition is discussed on the basis of the temperature-field-pressure phase diagram.

Integrated-fin gasket for palm cubic-anvil high pressure apparatus

We described an integrated-fin gasket technique for the palm cubic-anvil apparatus specialized for the high-pressure and low-temperature measurements. By using such a gasket made from the semi-sintered MgO ceramics and the tungsten-carbide anvils of 2.5 mm square top, we successfully generate pressures over 16 GPa at both room and cryogenic temperatures down to 0.5 K. We observed a pressure self-increment for this specific configuration and further characterized the thermally induced pressure variation by monitoring the antiferromagnetic transition temperature of chromium up to 12 GPa. In addition to enlarge the pressure capacity, such a modified gasket also improves greatly the surviving rate of electrical leads hanging the sample inside a Teflon capsule filled with the liquid pressure-transmitting medium. These improvements should be attributed to the reduced extrusion of gasket materials during the initial compression.

Possible Kondo physics near a metal-insulator crossover in the a-site ordered perovskite CaCu3Ir4O12

The A-site ordered perovskite (AA(3)')B(4)O(12) can accommodate transition metals on both A' and B sites in the crystal structure. Because of this structural feature, it is possible to have narrow-band electrons interacting with broadband electrons from different sublattices. Here we report a new A-site ordered perovskite (CaCu(3))Ir(4)O(12) synthesized under high pressure. The coupling between localized spins on Cu(2+) and itinerant electrons from the Ir-O sublattice makes Kondo-like physics take place at a temperature as high as 80 K. Results from the local density approximation calculation have confirmed the relevant band structure. The magnetization anomaly found at 80 K can be well rationalized by the two-fluid model.

Pressure-induced heavy fermion superconductivity in the nonmagnetic quadrupolar system PrTi(2)Al(20)

We report the discovery of a pressure-induced heavy fermion superconductivity in a nonmagnetic orbital ordering state in the cubic compound PrTi(2)Al(20). In particular, we found that the transition temperature and the effective mass associated with the superconductivity are dramatically enhanced as the system approaches the putative quantum critical point of the orbital order. Our experiment indicates that the strong orbital fluctuations may provide a nonmagnetic glue for Cooper pairing.

Eating alone among community-dwelling Japanese elderly: association with depression and food diversity

Eating alone is an emerging social concern these days along with the background of serious aging population growth and increasing number of single-dwellers in Japan. However, little study is focused eating alone and its relation to the health status of community-dwelling elderly.

OBJECTIVES

To clarify the relations between eating alone and geriatric functions such as depression, quantitative subjective quality of life (QOL), activities of daily living (ADL) and dietary status of community-dwelling Japanese elderly.

DESIGN

A cross-sectional study.

SETTINGS

Tosa town, one of the "super-aged" towns in Japan.

PARTICIPANTS

The study population consisted of 856 community-dwelling elderly aged ≥65 living in Tosa town.

MEASUREMENTS

Eating alone and living arrangement was defined by the questionnaire. Geriatric functions were assessed by measuring activities of daily living (ADL), depressive symptom using 15-item geriatric depression scale (GDS-15), and quality of life (QOL). Food diversity was investigated as a measure of dietary quality using 11-item Food Diversity Score Kyoto (FDSK-11). Body mass index (BMI) was calculated using height and body weight during a medical assessment.

RESULTS

The proportion of the elderly who usually eat alone was 33.2% in this study population. Even among 697 elderly subjects who live with others, 136 persons (19.5%) ate alone. The participants who ate alone were significantly depressed according to the assessment using GDS-15 score (5.7±4.3 vs. 4.4±3.8, P<0.001). Those who ate alone have lower scores of QOL items than those who ate with others (Subjective sense of health: 52.5±21.9 vs. 55.7±20.2 P=0.035, Relationship with family: 74.1±23.5 vs. 78.9±18.6 P<0.001, Subjective happiness: 58.5±22.7 vs. 62.2±21.1 P=0.019). A significant close association was found between eating alone and lower food diversity (FDSK-11 score 9.9±1.3 vs. 10.2±1.3, P=0.002). BMI was lower in the elderly subjects who ate alone than those with others. By the multivariate analysis, depression was independently associated with eating alone in the logistic regression model adjusted for age, sex, BMI and food diversity as confounding factors (OR: 1.42, CI: 1.00-2.11, P=0.043). Food diversity was also significantly associated even after the adjustment of these confounding factors.

CONCLUSION

Eating alone is an important issue related to depression and QOL as well as dietary status of community-dwellingl elderly in Japan. This study shows the simple and inexpensive way "eating together" may contribute to improve depressive mood of elderly persons, with a strong message that supports of family, friends and neighbors are very important.

Pressure effect on the structural transition and suppression of the high-spin state in the triple-layer T'-La4Ni3O8

We report a comprehensive high-pressure study on the triple-layer T'-La4Ni3O8 with a suite of experimental probes, including structure determination, magnetic, and transport properties up to 50 GPa. Consistent with a recent ab inito calculation, application of hydrostatic pressure suppresses an insulator-metal spin-state transition at P(c)≈6  GPa. However, a low-spin metallic phase does not emerge after the high-spin state is suppressed to the lowest temperature. For P>20  GPa, the ambient T' structure transforms gradually to a T(†)-type structure, which involves a structural reconstruction from fluorite La-O2-La blocks under low pressures to rock-salt LaO-LaO blocks under high pressures. Absence of the metallic phase under pressure has been discussed in terms of local displacements of O2- ions in the fluorite block under pressure before a global T(†) phase is established.

Co[V2]o4: a spinel approaching the itinerant electron limit

Studies of the structure, magnetization, and resistivity under pressure on stoichiometric normal spinel Co[V(2)]O(4) single crystals show (i) absence of a structural distortion, (ii) abnormal magnetic critical exponents, and (iii) metallic conductivity induced by pressures at low temperatures. All these results prove that Co[V(2)]O(4) sits on the edge of the itinerant-electron limit. Compared with similar measurements on Fe[V(2)]O(4) and other A[V(2)]O(4) studies, it is shown that a critical V-V separation for a localized-itinerant electronic phase transition exists.

A nationwide survey for prevalence of hepatitis E virus antibody in qualified blood donors in Japan

BACKGROUND AND OBJECTIVES

  In previous studies, we reported the transmission of hepatitis E virus (HEV) by transfusion, and the frequent detection of HEV markers in Japanese blood donors with elevated ALT levels. For the current study, we carried out a nationwide survey of the prevalence of IgG anti-HEV in qualified blood donors throughout Japan.

MATERIALS AND METHODS

The 12,600 samples from qualified blood donors were collected from seven blood centres (1800 per centre) representing nearly all regions of Japan. Samples were from age- and sex-matched blood donors who tested negative for all the current blood screening tests. The samples were screened using the in-house IgG anti-HEV ELISA. Sequentially, the positive samples were tested by the commercial IgG anti-HEV ELISA.

RESULTS

Of 12,600 samples, 431 (3·4%) were regarded as positive for IgG anti-HEV. The prevalence of IgG anti-HEV was higher in eastern Japan (5·6%) than in western Japan (1·8%) (P<0·001), and was also age-dependent and higher in men (3·9%) than in women (2·9%) (P=0·002).

CONCLUSION

The spread of the domestic infection of HEV was observed in qualified blood donors in Japan. A higher prevalence of IgG anti-HEV was observed in male donors, older donors and in donors residing in eastern Japan. Further studies are necessary to clarify the potential risk of transfusion-transmission of HEV in Japan.

Effects of magnetic field and pressure on the intermediate valence state of YbPd

High field magnetization, magnetoresistance and pressure effects of magnetic susceptibility, thermal expansion and electrical resistivity were examined for the intermediate valence system YbPd, which undergoes two first-order transitions at T(1) = 125 K and T(2) = 105 K. Analyses of high field magnetization suggest that half of the Yb atoms have magnetic moments below 100 K up to 55 T. The Yb valence state and the first-order transitions are stable up to 55 T. On the other hand, T(1) and T(2) decrease with increasing pressure and the first-order transitions disappear at around 4 GPa. Above the critical pressure, the experimental results suggest that the intermediate valence state persists down to the lowest temperature or a heavy fermion state is formed. We will show that most experimental results are explained reasonably by assuming the first-order transitions as a valence order transition of Yb. The magnetic ordering temperature is decreased with increasing pressure, in contrast to other Yb intermediate valence or Kondo systems. This may be correlated with the instability of the valence ordered state in this compound.

A cubic-anvil high-pressure device for pulsed neutron powder diffraction

A compact cubic-anvil high-pressure device was developed for in situ neutron powder diffraction studies. In this device, a cubic shaped pressure medium is compressed by six anvils, and neutron beams pass through gaps between the anvils. The first high-pressure experiment using this device was conducted at J-PARC and clearly showed the neutron diffraction patterns of Pb. Combining the cubic-anvil high-pressure device with a pulsed neutron source will prove to be a useful tool for neutron diffraction experiments.

Development of pressure cell for specific heat measurement at low temperature and high Magnetic field

We report the performance of Ag-Pd-Cu alloy as the material of a pressure cell to carry out specific heat measurements at low temperatures and high magnetic fields. The Ag-Pd-Cu alloy is advantageous to reduce the background due to the nuclear specific heat in the pressure cell growing at low temperatures and high magnetic fields. We prepared 70-20-10 alloy composed of 70 mass % of Ag, 20 mass % of Pd, and 10 mass % of Cu. The maximum hardness over 100 HRB (Rockwell-B scale) is achieved by the heat treatment. The magnetization and susceptibility results show that the alloy includes a small amount of magnetic ions, whose concentration is smaller than that in the Be-Cu alloy. We confirm that the specific heat of a piston cylinder cell made of the 70-20-10 alloy increases smoothly from 0.2 to 9 K and the nuclear specific heat decreases drastically in magnetic field compared to that expected in the Be-Cu alloy. The pressure value in the cell at low temperature increases almost linearly up to P=0.4 GPa, which is nearly the limit of the inner piston made of the 70-20-10 alloy, with increasing of the load applied at room temperature.

Critical behavior of the ferromagnetic perovskite BaRuO3

A thorough study has been made of the physical properties under high pressure of the perovskite BaRuO3 synthesized under pressure; it includes the critical behavior in the vicinity of Tc to 1 GPa and the temperature dependences of resistivity and ac magnetic susceptibility up to 8 GPa. The ferromagnetism in BaRuO3 is suppressed at 8 GPa. Critical fluctuations in the vicinity of Tc have been found in BaRuO3 and they are enhanced under pressure. These observations are in sharp contrast to SrRuO3 where mean-field behavior is found at Tc.

Genetic diversity of longtail macaques (Macaca fascicularis) on the island of Mauritius: an assessment of nuclear and mitochondrial DNA polymorphisms

BACKGROUND

Individuals from an introduced population of longtail macaques on Mauritius have been extensively used in recent research. This population has low MHC gene diversity, and is thus regarded as a valuable resource for research.

METHODS

We investigated the genetic diversity of this population using multiple molecular markers located in mitochondrial DNA and microsatellite DNA loci on the autosomes and the Y chromosome. We tested samples from 82 individuals taken from seven study sites.

RESULTS AND CONCLUSIONS

We found this population to be panmictic, with a low degree of genetic variability. On the basis of an mtDNA phylogeny, we inferred that these macaques' ancestors originated from Java in Asia. Weak gametic disequilibrium was observed, suggesting decay of non-random associations between genomic genes at the time of founding. The results suggest that macaques bred in Mauritius are valuable as model animals for biomedical research because of their genetic homogeneity.

Competitive coexistence of superconductivity with antiferromagnetism in CeRhIn5

We carried out ac magnetic susceptibility measurements under pressures P on the heavy fermion antiferromagnet CeRhIn5. We report bulk superconductivity (SC) at ambient pressure with a transition temperature Tc approximately or equal to 90 mK. The degraded SC in a powdered or polished sample was restored by annealing, showing that the SC state is sensitive to inhomogeneity. In a coexistence region of the SC with antiferromagnetism (AF), we find that Tc(P)(n)TN(P)(1-n) = const where TN indicates a Néel temperature and n denotes a ratio of electronic specific heat coefficients below and above TN, indicating the competition of the SC and the AF for states at the Fermi surface.

Plasma ghrelin levels in healthy elderly volunteers: the levels of acylated ghrelin in elderly females correlate positively with serum IGF-I levels and bowel movement frequency and negatively with systolic blood pressure

Aging is associated with a decrease in growth hormone (GH) secretion, appetite and energy intake. As ghrelin stimulates both GH secretion and appetite, reductions in ghrelin levels may be involved in the reductions in GH secretion and appetite observed in the elderly. However, only preliminary studies have been performed on the role of ghrelin in elderly subjects. In this study, we sought to clarify the physiologic implications of the age-related alterations in ghrelin secretion by determining plasma ghrelin levels and other clinical parameters in healthy elderly subjects. Subjects were > or = 65 years old, corresponding to the SENIEUR protocol, had not had a resection of the upper gastrointestinal tract and had not been treated with hormones. One hundred and five volunteers (49 men and 56 women) were admitted to this study (73.4 +/- 6.3 years old). Plasma levels of acylated ghrelin in elderly female subjects positively correlated with serum IGF-I levels and bowel movement frequency and negatively with systolic blood pressure. In elderly men, desacyl ghrelin levels correlated only weakly with bowel movement frequency. These findings suggest that the plasma levels of the acylated form of ghrelin may influence the age-related alterations in GH/IGF-I regulation, blood pressure and bowel motility. These observational associations warrant further experimental studies to clarify the physiologic significance of these effects.

Interaction between desialylated hepatitis B virus and asialoglycoprotein receptor on hepatocytes may be indispensable for viral binding and entry

The cellular receptor for hepatitis B virus (HBV) infection has not yet been identified. The purpose of this study was to address the possibility of participation by desialylated HBV and the asialoglycoprotein receptor (ASGP-R) exclusively expressed on liver parenchymal cells, in infection. Assays for viral binding and entry were performed by culturing a hepatoblastoma cell line, HepG2, and HBV particles derived from the HBV carrier in the presence or absence of neuraminidase (NA). Viral binding and entry were clearly enhanced in the presence of NA, and the enhancement of the binding could be blocked by asialo-fetuin and ethylenediamine-tetraacetic acid (EDTA). In addition, covalently closed circular (CCC)-DNA, as a marker of infectivity, was detected in the presence of NA, but not in its absence. The optimal concentration of NA raised infectivity more than 1000 times. We concluded that this method makes it feasible to evaluate the infectivity of HBV in vitro and that ASGP-R may be a specific HBV receptor once viral particles are desialylated.

Common carotid intima-media thickness is predictive of all-cause and cardiovascular mortality in elderly community-dwelling people: Longitudinal Investigation for the Longevity and Aging in Hokkaido County (LILAC) study

Several cohort studies have examined the association of carotid intima-media thickness (IMT) with the risk of stroke or myocardial infarction in apparently healthy persons. We investigated the predictive value of IMT of cardiovascular mortality in elderly community-dwelling people, beyond the prediction provided by age and MMSE, assessed by means of a multivariate Cox model. Carotid IMT and plaque were evaluated bilaterally with ultrasonography in 298 people older than 75 years (120 men and 178 women, average age: 79.6 years). The LILAC study started on July 25, 2000. Consultations were repeated every year. The follow-up ended on November 30, 2004. During the mean follow-up span of 1152 days, 30 subjects (21 men and nine women) died. Nine deaths were attributable to cardiovascular causes (myocardial infarction: two men and three women; stroke: two men and two women). The age- and MMSE-adjusted relative risk (RR) and 95% confidence interval (95% CI) of developing all-cause mortality was assessed. A 0.3 mm increase in left IMT was associated with a RR of predicted 1.647 (1.075-2.524), and a similar increase in right IMT with a RR of 3.327 (1.429-7.746). For cardiovascular mortality, the corresponding RR values were 2.351 (1.029-5.372) and 2.890 (1.059-7.891), respectively. Carotid IMT assessed by ultrasonography is positively associated with an increased risk of all-cause and cardiovascular death in elderly community-dwelling people.

Effect of aging on blood pressure in Leh, Ladakh, a high-altitude (3524 m) community, by comparison with a Japanese town

The effect of aging on blood pressure (BP) and heart rate (HR) was investigated in a cross-sectional study in the high-altitude community of Leh, Ladakh (altitude: 3524 m) and a Japanese community in U town, Hokkaido (altitude: 25 m). BP and HR were obtained in a sitting position from 332 subjects 13-81 years of age in Ladakh, and from 216 Japanese citizens, 24-79 years of age. Measurements were taken after a 2-min rest, using a semi-automated BP device (UA-767 PC, A and D Co. LTD, Tokyo). High-altitude people showed higher diastolic BP and HR values than lowland people (83.2 vs. 76.9 mmHg and 78.6 vs. 69.2 bpm, P < 0.001), but no difference in systolic BP. Highland people also showed a steeper BP increase with age than the lowland people (systolic BP: 0.7476 vs. 0.3179 mmHg/year, P < 0.0005; diastolic BP: 0.3196 vs. 0.0750 mmHg/year, P < 0.001). This chronoecologic investigation in Ladakh examined the circulation as a physiological system at high-altitude. Our data indicate the need for a more comprehensive cardiovascular assessment for a better diagnosis and a more fruitful treatment. Longitudinal observations of effects of socio-ecologic factors on the cardiovascular system should help prevent strokes and other cardiovascular events, especially at high altitude.

Depressive mood is independently related to stroke and cardiovascular events in a community

By means of a multivariate Cox model, we investigated the predictive value of a depressive mood on vascular disease risk in middle-aged community-dwelling people. In 224 people (88 men and 136 women; mean age: 56.8 +/- 11.2 years) of U town, Hokkaido (latitude: 43.45 degrees N, longitude: 141.85 degrees E), a chronoecological health watch was started in April 2001. Consultations were repeated every 3 months. Results at the November 30, 2004 follow-up are presented herein. 7-day/24-h blood pressure (BP) and heart rate (HR) monitoring started on a Thursday, with readings taken at 30-min intervals between 07:00 h and 22:00 h and at 60-min intervals between 22:00 h and 07:00 h. Data stored in the memory of the monitor (TM-2430-15, A and D company, Japan) were retrieved and analyzed on a personal computer with a commercial software for this device. Subjects were asked to answer a self-administered questionnaire inquiring about 15 items of a depression scale, at the start of study and again after 1-2 years. Subjects with a score higher by at least two points at the second versus first screening were classified as having a depressive mood. The other subjects served as the control group. The mean follow-up time was 1064 days, during which four subjects suffered an adverse vascular outcome (myocardial infarction: one man and one woman; stroke: two men). Among the variables used in the Cox proportional hazard models, a depressive mood, assessed by the Geriatric Depression Scale (GDS), as well as the MESOR of diastolic (D) BP (DBP-MESOR) and the circadian amplitude of systolic (S) BP (SBP-Amplitude) showed a statistically significant association with the occurrence of adverse vascular outcomes. The GDS score during the second but not during the first session was statistically significantly associated with the adverse vascular outcome. In univariate analyses, the relative risk (RR) of developing outcomes was predicted by a three-point increase in the GDS scale (RR = 3.088, 95% CI: 1.375-6.935, P = 0.0063). Increases of 5 mmHg in DBP-MESOR and of 3 mmHg in SBP-Amplitude were associated with RRs of 2.143 (95% CI: 1.232-3.727, P = 0.0070) and 0.700 (95% CI: 0.495-0.989, P = 0.0430), respectively. In multivariate analyses, when both the second GDS score and the DBP-MESOR were used as continuous variables in the same model, GDS remained statistically significantly associated with the occurrence of cardiovascular death. After adjustment for DBP-MESOR, a three-point increase in GDS score was associated with a RR of 2.172 (95% CI: 1.123-4.200). Monday endpoints of the 7-day profile showed a statistically significant association with adverse vascular outcomes. A 5 mmHg increase in DBP on Monday was associated with a RR of 1.576 (95% CI: 1.011-2.457, P = 0.0446). The main result of the present study is that in middle-aged community-dwelling people, a depressive mood predicted the occurrence of vascular diseases beyond the prediction provided by age, gender, ABP, lifestyle and environmental conditions, as assessed by means of a multivariate Cox model. A depressive mood, especially enhanced for 1-2 years, was associated with adverse vascular outcomes. Results herein suggest the clinical importance of repetitive assessments of a depressive mood and the need to take sufficient care of depressed subjects. Another result herein is that circadian and circaseptan characteristics of BP variability measured 7-day/24-h predicted the occurrence of vascular disease beyond the prediction provided by age, gender, depressive mood and lifestyle, as assessed by means of a multivariate Cox model. Earlier, we showed that the morning surge in BP on Mondays was statistically significantly higher compared with other weekdays. Although a direct association between the Monday surge in BP and cardiovascular events could not be demonstrated herein, it is possible that the BP surge on Monday mornings may also trigger cardiovascular events. We have shown that depressive people exhibit a more prominent circaseptan variation in SBP, DBP and the double product (DP) compared to non-depressed subjects. In view of the strong relation between depression and adverse cardiac events, studies should be done to ascertain that depression is properly diagnosed and treated. Chronodiagnosis and chronotherapy can reduce an elevated blood pressure and improve the altered variability in BP and HR, thus reducing the incidence of adverse cardiac events. This recommendation stands at the basis of chronomics, focusing on prehabilitation in preference to rehabilitation, as a public service offered in several Japanese towns.

Arterial stiffness independently predicts cardiovascular events in an elderly community — Longitudinal Investigation for the Longevity and Aging in Hokkaido County (LILAC) study

We investigated the predictive value of arterial stiffness to assess cardiovascular risk in elderly community-dwelling people by means of a multivariate Cox model. In 298 people older than 75 years (120 men and 178 women, average age: 79.6 years), brachial-ankle pulse wave velocity (baPWV) was measured between the right arm and ankle in a supine position. The LILAC study started on July 25, 2000, consultation was repeated yearly, and the last follow-up ended on November 30, 2004. During this follow-up span of 1227 days, there were nine cardiovascular deaths, the cause of death being myocardial infarction for two men and three women or stroke for two men and two women. In Cox proportional hazard models, baPWV as well as age, Mini-Mental State Examination (MMSE), Hasegawa Dementia Scale Revised (HDSR) and the low-frequency/high-frequency (LF/HF) ratio showed a statistically significant association with the occurrence of cardiovascular death. A two-point increase in MMSE and HDSR score significantly protected against cardiovascular death, the relative risk (RR) being 0.776 (P = 0.0369) and 0.753 (P = 0.0029), respectively. The LF/HF ratio also was significant (P = 0.025), but the other indices of HRV were not. After adjustment for age and HDSR, a 200 cm/s increase in baPWV was associated with a 30.2% increase in risk (RR = 1.302, 95% CI: 1.110-1.525), and a 500 cm/s increase in baPWV with a 93.3% increase in risk (RR = 1.933, 95% CI: 1.300-2.874, P = 0.0011), whereas the LF/HF ratio was no longer associated with a statistically significant increase in cardiovascular mortality. In elderly community-dwelling people, arterial stiffness measured by means of baPWV predicted the occurrence of cardiovascular death beyond the prediction provided by age, gender, blood pressure and cognitive functions. baPWV should be added to the cardiovascular assessment in various clinical settings, including field medical surveys and preventive screening. The early detection of risk by chronomics allows the timely institution of prophylactic measures, thereby shifting the focus from rehabilitation to prehabilitation medicine, as a public service to several Japanese towns.