Association between oral health and nutritional status among older patients requiring long-term care who received home-visit dental care

PURPOSE

This study examined the association between oral health and nutritional status among older patients receiving home-visit dental care.

METHODS

This study enrolled 110 older patients (age ≥65 years) requiring long-term care who received home-visit dental care. The oral health indicators evaluated included number of teeth, occlusal support, number of functional teeth, tongue pressure, tongue coating index (TCI), and rinsing ability. Nutritional indicators included skeletal muscle mass index (SMI) and the mini-nutritional assessment short-form (MNA-SF). A multivariate modified Poisson regression analysis (adjusted for age, sex, medical history, care level, and housing type) was used to calculate prevalence ratios and 95% confidence intervals (CIs).

RESULTS

The prevalence ratio for low SMI was not significantly higher for patients with ≥20 teeth than for those with 1-19 or no teeth. Number of teeth was not significantly associated with MNA-SF score. A high TCI score (2.15, 95% CI: 1.07-4.32) and poor rinsing ability (2.32, 95% CI: 1.25-4.30) were significantly associated with low SMI. High TCI scores were associated with low scores in MNA-SF categories (1.25, 95% CI: 1.01-1.55).

CONCLUSION

TCI and rinsing ability, rather than number of teeth, were associated with nutritional status in older patients requiring long-term care.

Associations of Dental Health With the Progression of Hippocampal Atrophy in Community-Dwelling Individuals: The Ohasama Study

BACKGROUND AND OBJECTIVES

Although tooth loss and periodontitis have been considered risk factors of Alzheimer disease, recent longitudinal researches have not found a significant association with hippocampal atrophy. Therefore, this study aimed to clarify a longitudinal association between the number of teeth present (NTP) and hippocampal atrophy dependent on the severity of periodontitis in a late middle-aged and older adult population.

METHODS

This study included community-dwelling individuals aged 55 years or older who had no cognitive decline and had undergone brain MRI and oral and systemic data collection twice at 4-year intervals. Hippocampal volumes were obtained from MRIs by automated region-of-interest analysis. The mean periodontal probing depth (PD) was used as a measure of periodontitis. Multiple regression analysis was performed with the annual symmetric percentage change (SPC) of the hippocampal volume as the dependent variable and including an interaction term between NTP and mean PD as the independent variable. The interaction details were examined using the Johnson-Neyman technique and simple slope analysis. The 3-way interaction of NTP, mean PD, and time on hippocampal volume was analyzed using a linear mixed-effects model, and the interaction of NTP and time was examined in subgroups divided by the median mean PD. In all models, dropout bias was adjusted by inverse probability weighting.

RESULTS

Data of 172 participants were analyzed. The qualitative interaction between NTP and the mean PD was significant for the annual SPC in the left hippocampus. The regression coefficient of the NTP on the annual SPC in the left hippocampus was positive (B = 0.038, p = 0.026) at the low-level mean PD (mean -1 SD) and negative (B = -0.054, p = 0.001) at the high-level mean PD (mean +1 SD). Similar results were obtained in the linear mixed-effects model; the interaction of NTP and time was significant in the higher mean PD group.

DISCUSSION

In a late middle-aged and older cohort, fewer teeth were associated with a faster rate of left hippocampal atrophy in patients with mild periodontitis, whereas having more teeth was associated with a faster rate of atrophy in those with severe periodontitis. The importance of keeping teeth healthy is suggested.

Regular dental visits, periodontitis, tooth loss, and atherosclerosis: The Ohasama study

Objective

We aimed to explore the association between regular dental visits and atherosclerosis and between periodontitis, number of remaining teeth, and atherosclerosis among community dwellers in Japan.

Background

Few studies have examined the association between regular dental visits, periodontitis, tooth loss, and atherosclerosis in community dwellers in Japan.

Methods

The participants of this cross‐sectional study included community dwellers aged ≥55 years and residing in Ohasama. Exposure variables were regular dental visits; periodontitis, defined as radiographic alveolar bone loss (BL); the Centers for Disease Control/American Academy of Periodontology (CDC/AAP) classification; and number of remaining teeth. The primary outcome was atherosclerosis, defined as maximum carotid intima‐media thickness ≥1.1 mm or confirmation of atheromatous plaque.

Results

Of 602 participants, 117 had atherosclerosis. In the multivariate model, compared to those with regular dental visits, the odds ratio (OR) (95% confidence intervals [CIs]) of atherosclerosis among those with the absence of regular dental visits was 2.16 (1.03–4.49). Regarding BL‐max, compared with those in the first quartile, ORs (95% CIs) of those in the second, third, and fourth quartiles were 1.15 (0.65–2.30), 0.65 (0.32–1.35), and 1.57 (0.81–3.01), respectively. Regarding CDC/AAP classification, compared to those with no or mild periodontitis, ORs (95% CIs) for those with moderate and severe periodontitis were 2.48 (0.61–10.1) and 4.26 (1.01–17.5), respectively. Regarding the number of remaining teeth, compared to those with ≥20 teeth, ORs (95%CIs) for those with 10–19 and 1–9 teeth were 1.77 (1.004–3.12) and 0.96 (0.52–1.80), respectively.

Conclusion

The absence of regular dental visits and presence of periodontitis are associated with atherosclerosis among community dwellers in Japan.

Oral health-related quality of life is associated with the prevalence and development of depressive symptoms in older Japanese individuals: The Ohasama Study

OBJECTIVE

This prospective study investigated the cross-sectional association between impaired oral health-related quality of life (OHRQoL) and the prevalence of depressive symptoms, and the longitudinal association between impaired OHRQoL and development of depressive symptoms among older adults.

BACKGROUND

Previous studies have shown a relationship between poor oral health and depression among older adults; however, findings are inconsistent.

MATERIALS AND METHODS

Participants were 669 community-dwelling older Japanese individuals aged≥55 years (mean: 67.8 ± 7.2 years). Data of 296 participants were used for longitudinal analyses. OHRQoL was evaluated using the Oral Impacts on Daily Performances scale. Impaired OHRQoL was defined as the presence of at least one impact on the scale. Depressive symptoms were assessed using the Japanese version of the Zung self-rating depression scale with a cut-off score of 40.

RESULTS

The cross-sectional logistic regression model demonstrated that impaired OHRQoL was significantly associated with depressive symptoms (odds ratio [OR], 5.17; 95% confidence interval [CI], 2.99-8.95) independent of age, sex, body mass index, hypertension, cerebrovascular/cardiovascular disease, smoking, drinking alcohol, education, cognitive function, objective oral health (dentition status) and oral health behaviour (dental visit within 1 year). Similarly, impaired OHRQoL predicted the development of depressive symptoms within 4 years in a fully adjusted longitudinal model (OR, 6.00; 95% CI, 1.38-26.09).

CONCLUSION

Impaired OHRQoL was identified as a potential comorbidity of depressive symptoms and a predictor for depressive disorder later in life. OHRQoL may be a useful clinical outcome for elder patients with regard to their mental and oral health.

Relationship Between Oral Health and Fractures in Community-Dwelling Older Japanese Adults

OBJECTIVE

To investigate the relationship between poor oral health and the incidence of fall-related fractures in older Japanese individuals.

DESIGN

A 9-year prospective cohort study.

SETTING AND PARTICIPANTS

Participants comprised 937 community-dwelling older Japanese adults aged 70 years or older. They all lived in the Tsurugaya district, a suburban area of Sendai city, and underwent comprehensive geriatric assessment, including an oral examination, in a public facility.

MEASUREMENTS

The exposure variables were related to oral health status (posterior occlusal support, number of remaining teeth, and occlusal force). The outcome measure was the incidence of fall-related fractures, which was determined by National Health Insurance data. Analyzed covariates included age, sex, medical history, smoking, alcohol drinking, educational level, depressive symptoms, cognitive impairment, physical function, body mass index, and history of falls. Statistical relationships were examined by calculating hazard ratios (HRs) at 95% confidence intervals (CIs) using the Cox proportional hazard model.

RESULTS

In the multivariate analysis, the HRs of fall-related fractures were significantly higher in those with unilateral posterior occlusal support (HR, 2.72; 95% CI, 1.13-6.55) and no posterior occlusal support (HR, 2.58; 95% CI, 1.29-5.15) than in those with bilateral posterior occlusal support. The HRs (95% CIs) of fall-related fractures in individuals with 10-19 and 1-9 teeth and edentulous individuals were 1.77 (0.81-3.89), 2.67 (1.24-5.75), and 2.31 (1.01-5.28), respectively, compared to those with ≥20 teeth.

CONCLUSIONS AND IMPLICATIONS

Poor oral health status is a risk factor for the incidence of fall-related fractures in community-dwelling older Japanese individuals. The findings suggest that attention should be focused on oral health status to further understand the risk of fall-related fractures among community-dwelling older adults.

The Association between Number of Remaining Teeth and Maintenance of Successful Aging in Japanese Older People: A 9-Year Longitudinal Study

With population aging, an increasing attention has been paid to quality of life rather than mere longevity. Now, it is urgently needed to clarify predictors of well-being in later life, i.e., "successful aging (SA)." The aim of this study is to investigate whether the number of remaining teeth impacts on maintenance of SA among Japanese older people. The present study was conducted in Tsurugaya district, a suburban area of Sendai, in northern Japan, and included older people aged ≥ 70 years who had met the criteria for SA at a 2003 baseline survey. At the baseline survey, dentists obtained data for the number of remaining teeth. We obtained information about Long-term Care Insurance certification, including the dates of incident functional disability and death between 2003 and 2012. Data pertaining to health-related quality of life (HRQOL) were collected at the 2003 baseline survey and the 2012 follow-up survey. Maintenance of SA was defined in terms of survival, disability-free status and high HRQOL in both 2003 and 2012. Among 450 participants, 108 (24.0%) were considered to have maintained a state of SA. When participants were classified into three groups according to previous studies, in comparison with participants who retained 0-9 teeth, the multivariate prevalence ratios (95% confidence intervals) were 1.39 (0.81-2.36) for those who retained 10-19 teeth and 1.58 (1.002-2.50) for those who retained ≥ 20 teeth (p trend = 0.046). The present results suggest that retaining ≥ 20 teeth is associated with maintenance of SA among Japanese older people.

Practicalities of dose management for Japanese astronauts staying at the International Space Station

Japanese astronauts started staying at the International Space Station (ISS) in 2009, with each stay lasting for approximately 6 months. In total, seven Japanese astronauts have stayed at the ISS eight times. As there is no law for protection against space radiation exposure of astronauts in Japan, the Japan Aerospace Exploration Agency (JAXA) created its own rules and has applied them successfully to radiation exposure management for Japanese ISS astronauts, collaborating with ISS international partners. Regarding dose management, JAXA has implemented several dose limits to protect against both the stochastic effects of radiation and dose-dependent tissue reactions. The scope of the rules includes limiting exposure during spaceflight, exposure during several types of training, and exposure from astronaut-specific medical examinations. We, therefore, are tasked with calculating the dose from all exposure types applied to the dose limits annually for each astronaut. Whenever a Japanese astronaut is at the ISS, we monitor readings of an instrument in real-time to confirm that the exposed dose is below the set limits, as the space radiation environment can fluctuate in relation to solar activity.

The association between bilateral maximum occlusal force and all-cause mortality among community-dwelling older adults: The Tsurugaya project

PURPOSE

This study aimed to investigate the relationship between the bilateral maximum occlusal force (MOF) of full dental arches and all-cause mortality in a group of community-dwelling older males and females in Japan.

METHODS

This 13-year prospective cohort study was conducted among 815 older adults (395 male and 420 female) aged 70 years or over (mean age ± standard deviation: 75.1 ± 4.5 years). Bilateral MOF in the intercuspal position was recorded with horseshoe-shaped pressure-sensitive film. Participants were grouped by gender into tertiles according to MOF. Demographic variables, chronicity, comorbidity, physical status, cognitive and psychological status, social functioning, and blood chemistry data were also assessed. Information regarding all-cause mortality and migration was obtained from the Sendai Municipal Authority. Cox proportional hazard modeling was performed to assess all-cause mortality during the follow-up period.

RESULTS

In total, 159 male and 109 female participants died over a median 12.9-year follow-up period, and the cumulative mortality significantly increased with lower MOF in both males and females. The multivariate Cox proportional hazard model demonstrated a significant increase in the risk of all-cause mortality associated with lower tertiles of MOF, relative to the upper tertile in males (hazard ratio: 1.62; 95% confidence interval: 1.05-2.51) and females (hazard ratio: 1.94; 95% confidence interval: 1.10-3.56).

CONCLUSIONS

There was a significant and independent association of bilateral MOF with all-cause mortality in community-dwelling elderly males and females in Japan. These findings suggested that maintenance of oral functioning contributes to general health.

Dental Status is Associated With Incident Functional Disability in Community-Dwelling Older Japanese: A Prospective Cohort Study Using Propensity Score Matching

Background

A growing number of epidemiology studies have shown that poor oral health is associated with an increased incidence of functional disability. However, there are few studies in which the confounding bias is adjusted appropriately. In this study, we examined whether dental status is associated with functional disability in elderly Japanese using a 13-year prospective cohort study after elimination of confounding factors with propensity score matching.

Methods

Participants were community-dwelling Japanese aged 70 years or older who lived in the Tsurugaya district of Sendai (n = 838). The number of remaining teeth (over 20 teeth vs 0–19 teeth) was defined as the exposure variable. The outcome was the incidence of functional disability, defined as the first certification of long-term care insurance (LTCI) in Japan. The variables that were used to determine propensity score matching were age, sex, body mass index (BMI), medical history (stroke, hypertension, myocardial infarction, cancer, and diabetes), smoking, alcohol consumption, educational attainment, depression symptoms, cognitive impairment, physical function, social support, and marital status.

Results

As a result of the propensity score matching, 574 participants were selected. Participants with 0–19 teeth were more likely to develop functional disability than those with 20 or more teeth (hazard ratio 1.33; 95% confidence interval, 1.01–1.75).

Conclusions

In this prospective cohort study targeting community-dwelling older adults in Japan, having less than 20 teeth was confirmed to be an independent risk factor for functional disability even after conducting propensity score matching. This study supports previous publications showing that oral health is associated with functional disability.

Association between tooth loss and cognitive impairment in community-dwelling older Japanese adults: a 4-year prospective cohort study from the Ohasama study

BACKGROUND

Numerous prospective studies have investigated the association between the number of remaining teeth and dementia or cognitive decline. However, no agreement has emerged on the association between tooth loss and cognitive impairment, possibly due to past studies differing in target groups and methodologies. We aimed to investigate the association between tooth loss, as evaluated through clinical oral examinations, and the development of cognitive impairment in community-dwelling older adults while considering baseline cognitive function.

METHODS

This 4-year prospective cohort study followed 140 older adults (69.3% female) without cognitive impairment aged ≥65 years (mean age: 70.9 ± 4.3 years) living in the town of Ohasama, Iwate Prefecture, Japan. Cognitive function was evaluated with the Mini-Mental State Examination (MMSE) in baseline and follow-up surveys. Based on a baseline oral examination, the participants were divided into those with 0-9 teeth and those with ≥10 teeth. To investigate the association between tooth loss and cognitive impairment, we applied a multiple logistic regression analysis adjusted for age, sex, hypertension, diabetes, cerebrovascular/cardiovascular disease, hypercholesterolemia, depressive symptoms, body mass index, smoking status, drinking status, duration of education, and baseline MMSE score.

RESULTS

In the 4 years after the baseline survey, 27 participants (19.3%) developed cognitive impairment (i.e., MMSE scores of ≤24). Multiple logistic regression analysis indicated that participants with 0-9 teeth were more likely to develop cognitive impairment than those with ≥10 teeth were (odds ratio: 3.31; 95% confidence interval: 1.07-10.2). Age, male gender, and baseline MMSE scores were also significantly associated with cognitive impairment.

CONCLUSIONS

Tooth loss was independently associated with the development of cognitive impairment within 4 years among community-dwelling older adults. This finding corroborates the hypothesis that tooth loss may be a predictor or risk factor for cognitive decline.

Teriparatide improves volumetric bone mineral density and fine bone structure in the UIV+1 vertebra, and reduces bone failure type PJK after surgery for adult spinal deformity

We conducted a prospective comparative study of the effect of teriparatide therapy for preventing vertebral-failure-type PJK after reconstructive surgery for adult spinal deformity. Prophylactic teriparatide improved the volumetric bone mineral density and fine bone structure of the vertebra above the upper-instrumented vertebra and reduced the incidence of vertebral-failure-type PJK.

INTRODUCTION

Proximal junctional kyphosis (PJK) is a complication after corrective surgery for spinal deformity. This study sought to determine whether teriparatide (TP) is an effective prophylactic against PJK type 2 (vertebral fracture) in surgically treated patients with adult spinal deformity (ASD).

METHODS

Forty-three patients who started TP therapy immediately after surgery and 33 patients who did not receive TP were enrolled in this prospective case series. These patients were female, over 50, surgically treated for ASD, and followed for at least 2 years. Preoperative and postoperative standing whole-spine X-rays and dual-energy X-ray absorptiometry scans, and multidetector CT images obtained before and 6 months after surgery were used to analyze the bone strength in the vertebra above the upper-instrumented vertebra (UIV+1).

RESULTS

Mean age was 67.9 years. After 6 months of treatment, mean hip-bone mineral density (BMD) increased from 0.721 to 0.771 g/cm² in the TP group and decreased from 0.759 to 0.729 g/cm² in the control group. This percent BMD change between groups was significant (p < 0.05). The volumetric BMD (326 to 366 mg/cm³) and bone mineral content (BMC) (553 to 622 mg) at UIV+1 were also significantly increased in TP group. The bone volume/tissue volume ratio increased from 46 to 54 % in the TP group, and the trabecular bone thickness and number increased by 14 and 5 %, respectively. At the 2-year follow-up, the PJK type 2 incidence was significantly lower in the TP group (4.6 %) than in the control group (15.2 %; p = .02).

CONCLUSIONS

Prophylactic TP treatment improved the volumetric BMD and fine bone structure at UIV+1 and reduced the PJK-type 2 incidence.

Association Between Tooth Loss, Receipt of Dental Care, and Functional Disability in an Elderly Japanese Population: The Tsurugaya Project

OBJECTIVES

To examine whether number of remaining teeth and regular dental care affect incident functional disability in elderly Japanese adults.

DESIGN

Prospective cohort study.

SETTING

Tsurugaya district, Sendai, Japan.

PARTICIPANTS

Community-dwelling individuals aged 70 and older (N = 834).

MEASUREMENTS

The outcome measurement was incident functional disability, defined as first certification of long-term care insurance in Japan, which is determined on the basis of a strictly established uniform nationwide standard. During a median follow-up of 7.9 years (interquartile range 4.8-7.9 years), information on long-term care insurance was obtained from the Sendai Municipal Authority. Oral health was assessed according to number of remaining teeth and presence or absence of regular dental care. Data were also collected on age, sex, body mass index, medical history, smoking, alcohol consumption, duration of education, depressive symptoms, cognitive impairment, physical functioning, and social support.

RESULTS

Participants with 10 to 19 teeth (adjusted hazard ratio (aHR) = 1.42, 95% confidence interval (CI) = 1.03-1.94), one to nine teeth (aHR = 1.46, 95% CI = 1.04-2.03), and no teeth (aHR = 1.49, 95% CI = 1.03-2.14) were more likely to develop functional disability than those with 20 or more teeth. There was no significant difference in risk of functional disability between participants with 20 or more teeth and those with zero to 19 teeth who were receiving regular dental care, whereas those with zero to 19 teeth without regular dental care had a significantly greater risk of functional disability than those with 20 or more teeth (HR = 1.46, 95% CI = 1.11-1.92).

CONCLUSION

Tooth loss was associated with greater risk of functional disability in community-dwelling elderly Japanese. Regular dental care might moderate the risk of functional disability in elderly individuals with missing teeth.

Association study between casein kinase 1 epsilon gene and methamphetamine dependence

Casein kinase 1 epsilon (CKIepsilon) is a component of the DARPP-32 in second-messenger pathway. CKIepsilon phosphorylates and activates DARPP-32, a key molecule in various complex signaling pathways, including dopamine and glutamine signaling, which have both been demonstrated to be main pathways in substance dependence. A recent clinical study showed that rs135745, a noncoding single nucleotide polymorphism of the 3'-untranslated region of the CSNK1E gene, was associated with the intensity of the subjective response to an oral amphetamine dose in normal volunteers. Differences in sensitivity to the drug should affect development of dependence to it. Hence, we genotyped rs135745 of the CSNK1E (MIM 600863) gene in 215 patients with methamphetamine dependence and 274 age- and gender-matched normal controls. No significant differences in genotype and allele frequencies were observed between the patients with methamphetamine dependence and controls. There was also no significant association between rs135745 and the clinical characteristics of methamphetamine dependence and co-morbid methamphetamine psychosis (e.g., age of first consumption, latency of psychosis, prognosis of psychosis after therapy, spontaneous relapse of psychotic symptoms, and poly-substance abuse status). The present findings suggest that having a genetic variant of the CSNK1E gene did not affect susceptibility to methamphetamine dependence or psychosis, at least in a Japanese population.

Trichostatin A, a histone deacetylase inhibitor, suppresses synovial inflammation and subsequent cartilage destruction in a collagen antibody-induced arthritis mouse model

OBJECTIVE

To investigate the effect of the histone deacetylase (HDAC) inhibitor, trichostatin A (TSA), on joint inflammation and cartilage degeneration in a collagen antibody-induced arthritis (CAIA) mouse model.

METHODS

CAIA mice were given daily subcutaneous injections of various concentrations of TSA (0, 0.5, 1.0, and 2.0 mg/kg) and various parameters were monitored for 14 days. On Day 15, the hind paws were examined histologically. To investigate the effects of TSA on the expressions of matrix metalloproteinase (MMP)-3, MMP-13, tissue inhibitor of MMP-1 (TIMP-1), and acetyl-H4 by chondrocytes, another group of mice was sacrificed on Day 6. In vitro direct effect of TSA was examined by real-time PCR for mRNA of type II collagen, aggrecan, MMP-3, and MMP-13 in murine chondrogenic ATDC5 cells after pro-inflammatory cytokine stimulation.

RESULTS

In the TSA-treated group, clinical arthritis was significantly ameliorated in a dose-dependent manner. The severity of synovial inflammation and the cartilage destruction score were significantly lower in the TSA 2.0 mg/kg group compared to the other TSA-treated groups. On immunohistochemistry, the number of MMP-3 and MMP-13-positive chondrocytes was significantly lower in the TSA 2.0 mg/kg group than in the control group. In contrast, the number of TIMP-1-positive cells and acetyl-histone H4-positive cells was significantly higher in the TSA 2.0mg/kg group than in the control group. TSA suppressed interleukin 1-beta and tumor necrosis factor-alpha-stimulated up-regulation of MMP-3, but not MMP-13 mRNA expression by ATDC5.

CONCLUSION

The systemic administration of TSA ameliorated synovial inflammation in CAIA mice. Subsequently cartilage destruction was also suppressed by TSA, at least in part, by modulating chondrocyte gene expression.

Objective Assessment of Nerve Injury after Greater Saphenous Vein Stripping

AIM

The complication of nerve injury after greater saphenous vein stripping for varicosity is subjective, and a method for objective evaluation has never been established. The aim of this study was to evaluate postoperative sensory changes by quantitative assessment of current perception threshold (CPT), and to clarify the relation between CPT and symptoms.

PATIENTS AND METHODS

Between January 2003 and August 2005, 27 limbs in 18 patients were enrolled. Quantitative sensory function was determined through CPT using a Neurometer (Neurotron, Inc., USA), with which saphenous nerve neural fiber selective minimum sensing values against three electrical stimuli (2000, 250, 5 Hz) were measured. CPT measurements were scheduled on the day before the operation, and 2-7 days, 1, 3, and 6 months after the operation.

RESULTS

An increase in CPT value of more than 20% or decrease to below 50% compared to the preoperative value with at least two stimuli was defined as CPT abnormality. Subjective symptoms were observed in 13 limbs in the early postoperative period, and 10 limbs showed CPT abnormality. In 6 limbs with a CPT increase over 20% with all three stimuli, neurological symptoms continued for 6 months.

CONCLUSIONS

CPT evaluation provides an objective indication of neurological symptoms in the lower limb following varicose vein surgery.

Possible association of ?-arrestin 2 gene with methamphetamine use disorder, but not schizophrenia

Recent investigations suggest that the AKT/glycogen synthase kinase 3 (GSK3) signaling cascade may be associated with the pathophysiology of schizophrenia and methamphetamine (METH) use disorder. One important molecule related to this cascade is beta-arrestin 2 (ARRB2). We therefore conducted a genetic case-control association analysis of the gene for ARRB2 with schizophrenia and METH use disorder in a Japanese population (547 people with schizophrenia, 177 with METH use disorder and 546 controls). A possible association of 'tag single nucleotide polymorphisms (SNPs)' was found in METH use disorder (rs1045280: P(genotype) = 0.0118, P(allele) = 0.00351; rs2036657: P(allele) = 0.0431; rs4790694: P(genotype) = 0.0167, P(allele) = 0.0202), but no association was found with schizophrenia. We also evaluated the gene-gene interactions among ARRB2, AKT1, and GSK3B, which we previously reported for each of these diseases. However, no interaction was seen in our samples. This is the first association analysis of ARRB2, and our results indicate that ARRB2 may play a role in the pathophysiology of METH use disorder.

No association between CART (cocaine- and amphetamine-regulated transcript) gene and methamphetamine dependence

Cocaine- and amphetamine-regulated transcript (CART) was originally discovered as a peptide that increased in the rat striatum after injection of a psychostimulant drug, such as cocaine or amphetamine, and is suggested to play potential roles in drug dependence. We tested the genetic association between the CART gene and methamphetamine (METH) dependence and/or psychosis. The subjects were 203 patients with METH dependence and 239 age- and gender-matched healthy controls. Two single nucleotide polymorphisms (SNPs) of the CART gene, -156A>G and IVS1 + 224G>A, were examined . There were no significant differences in genotype and allele distributions of the polymorphisms between patients with METH dependence and/or psychosis and controls. Neither were significant differences in subgroups of clinical phenotypes, for example, age at first consumption of METH, latency to onset of psychotic symptoms after the first consumption of METH, prognosis of psychosis after therapy, complication of spontaneous relapse to a psychotic state, or multisubstance abuse status, observed. The present findings suggest that the CART gene may not play a pivotal role in the development of METH dependence and psychosis, at least in a Japanese population.

Association study of the tumor necrosis factor-alpha gene and its 1A receptor gene with methamphetamine dependence

Recent preclinical findings that repeated treatment with methamphetamine (METH) induced an increase in tumor necrosis factor-alpha (TNF-alpha) mRNA in some brain regions and that TNF-alpha blocked METH neurotoxicity and rewarding effects suggest TNF-alpha, a multifunctional pro-inflammatory cytokine, may be involved in METH dependence. We hypothesized that genetic polymorphisms of the TNF-alpha gene and its receptor genes may be associated with vulnerability to METH dependence. Genetic association of -308G>A and -857C>T in the promotor region of the TNF-alpha gene, and 36A>G in exon 1 of the TNF receptor 1A gene (TNFR-SF1A), were analyzed in patients with METH dependence (n = 185) and healthy controls (n = 221) in a Japanese population. No significant association of alleles or haplotypes of the TNF-alpha or TNFR-SF1A genes with METH dependence was found. Neither was any significant association of clinical phenotype with METH dependence found. These results suggest that genetic variations in the TNF-alpha gene and its receptor genes may not be involved in individual vulnerability to METH dependence.

Association Study of the Dihydropyrimidinase-Related Protein 2 Gene and Methamphetamine Psychosis

Dihydropyrimidinase-related protein 2 (DRP-2 or DPYSL-2)mediates the intracellular response to collapsin, a repulsive extracellular guidance cue or axonal outgrowth. DRP-2 is also referred to as collapsin response mediator protein 2 (CRMP-2). We have previously demonstrated that the DRP-2 gene is associated with susceptibility to schizophrenia, but not to bipolar disorders. In addition, a genetic association was observed with paranoid-type schizophrenia, but not with hebephrenic-type schizophrenia. It has been well documented that repeated abuse of methamphetamine (METH) for a long period frequently produces psychotic symptoms, such as auditory hallucinations and delusions that are hardly distinguishable from those of paranoid-type schizophrenia. Therefore, we hypothesized that a certain genetic variant of the DRP-2 gene may affect individual vulnerability to the development of METH-induced psychosis. We examined the genetic association by a case-control method. The polymorphism *2236T>C in the 3' untranslated region of the DRP-2 gene, which has been shown to be a negative genetic risk factor for paranoid-type schizophrenia, was analyzed in 198 patients with METH psychosis and 221 corresponding healthy controls in a Japanese population. No significant association of the DRP-2 gene with METH psychosis was found. Neither did we find an association with the clinical phenotype of METH psychosis, such as the age of first consumption of METH, latency to development of psychosis after METH abuse, prognosis of psychosis after detoxification from METH use, complication of spontaneous relapse of psychosis without reconsumption of the drug, or multisubstance abuse status. These findings indicate that a genetic variant of the DRP-2 gene may not affect the risk of METH psychosis or any clinical phenotype of the disorder.

Linkage disequilibrium and association with methamphetamine dependence/psychosis of mu-opioid receptor gene polymorphisms

Several studies indicate that the mu-opioid receptor plays a role in addiction not only to opiate drugs but also to alcohol and non-opiate addictive drugs. Our studies aim to reveal the associations between gene polymorphisms and methamphetamine (MAP) dependence/psychosis. We newly identified several polymorphisms and four substantial linkage disequilibrium (LD) blocks in the mu-opioid receptor (OPRM1) gene. We found significant differences in both genotype and allele frequencies of the single-nucleotide polymorphism (SNP) IVS2+G691C between control (n=232) and MAP-dependent/psychotic patients (n=128). There was also a significant association between IVS2+G691C and patients with transient psychosis. These results suggest that the OPRM1 gene variations may be a factor in development and prognosis of MAP psychosis.

Impaired ambulatory venous function in lymphedema assessed by near-infrared spectroscopy

AIM

The aim of this study was to investigate venous function in patients with leg lymphedema during exercise using near-infrared spectroscopy (NIRS), compared with that of patients with chronic venous insufficiency (CVI).

METHODS

Forty-three legs of 33 patients (5 males, 28 females; mean age: 53 years) with leg lymphedema without varicose veins or deep vein thrombosis underwent a treadmill walking test with simultaneous NIRS. For comparison, 136 legs of 91 patients (35 males, 56 females; mean age: 56 years) with varicose veins as a CVI group and 45 legs of 38 healthy volunteers (23 males, 15 females; mean age: 50 years) were also evaluated in the same method. Deoxygenated hemoglobin (HHb) was continuously measured during exercise, and the ambulatory venous retention index (AVRI) of each leg was obtained from the serial changes in HHb.

RESULTS

The mean AVRI of the lymphedema group was significantly higher than that of healthy legs and significantly lower than of legs with moderate or severe CVI. Furthermore, it was similar to that in the mild CVI group.

CONCLUSIONS

Venous function is impaired in exercising legs with lymphedema, and corresponds to that in legs with mild venous insufficiency. The treatment of lymphedema should take CVI into consideration.

Novel transdermal photodynamic therapy using ATX-S10·Na(II) induces apoptosis of synovial fibroblasts and ameliorates collagen antibody-induced arthritis in mice

We aimed to test the effect of transdermal photodynamic therapy (PDT) on synovial proliferation in vitro and in vivo, using a novel photosensitizer, ATX-S10.Na(II). Synovial fibroblasts were obtained from patients with RA (RASF). Cell viability with or without PDT was determined by MTT assay. Cell morphology was examined by light and transmission electron microscopy. DNA fragmentation was labeled by TUNEL stain. Collagen antibody-induced arthritis (CAIA) was induced in DBA/1 mice, and the effects of transdermal PDT were evaluated by clinical and histological examination. PDT showed drug concentration-dependent and laser dose-dependent cytotoxicity on RASF. TUNEL stain and TEM study revealed the induction of apoptotic cell death of RASF. Transdermal PDT significantly reduced clinical arthritis and synovial inflammation in this model of arthritis. These results suggest that transdermal PDT using ATX-S10.Na(II) might be a novel less invasive treatment strategy for small joint arthritis and tenosynovitis.

Haplotype association between GABAA receptor gamma2 subunit gene (GABRG2) and methamphetamine use disorder

Psychostimulant use disorder and schizophrenia have a substantial genetic basis. Evidence from human and animal studies on the involvement of the gamma-aminobutyric acid (GABA) system in methamphetamine (METH) use disorder and schizophrenia is mounting. As we tested for the association of the human GABA(A) receptor gamma 2 subunit gene (GABRG2) with each diagnostic group, we used a case-control design with a set of 178 subjects with METH use disorder, 288 schizophrenics and 288 controls. First, we screened 96 controls and identified six SNPs in GABRG2, three of whom we newly reported. Next, we selected two SNPs, 315C>T and 1128+99C>A, as representatives of the linkage disequilibrium blocks for further case-control association analysis. Although no associations were found in either allelic or genotypic frequencies, we detected a haplotypic association in GABRG2 with METH use disorder, but not with schizophrenia. This finding partly replicates a recent case-control study of GABRG2 in METH use disorder, and thus indicates that GABRG2 may be one of the susceptibility genes of METH use disorder.

Attenuation of the effect of remote muscle contraction on the soleus H-reflex during plantar flexion

OBJECTIVE

We investigated to what extent the facilitation of the soleus (Sol) Hoffmann (H-) reflex during a phasic voluntary wrist flexion (Jendrássik maneuver, JM) can be modulated by graded plantar flexion force and conditioning wrist flexion force.

METHODS

The subjects were asked to perform phasic wrist flexion under a reaction time condition. Sol H-reflex was evoked by stimulating the right tibial nerve at various time intervals (50-400ms) after the 'Go' signal for initiating JM while the ankle was at rest and while plantarflexing. The level of tonic plantar flexion force (isometric contraction of 10, 20 and 30% of maximal EMG) and conditioning wrist flexion (isometric contraction of 30, 50 and 80% of maximum voluntary contraction) during JM was graded systematically.

RESULTS

Although JM facilitation could be seen 80-120ms after the flexor carpi radialis (FCR) EMG onset even while plantarflexing, the magnitude of JM facilitation under plantar flexion was significantly decreased compared to that at rest. The degree of decrease in JM facilitation did not depend on the level of plantar flexion force. In contrast, the degree of JM facilitation was proportional to the level of wrist flexion force while the ankle was at rest and while plantarflexing, though the amount of JM facilitation significantly decreased while plantarflexing.

CONCLUSIONS

JM facilitation of Sol H-reflex is decreased while performing tonic voluntary contraction of the homonymous muscle. The degree of decrease in JM facilitation is independent of the level of homonymous muscle contraction, but depends on the level of remote FCR contraction. In clinical application, when we intend to elicit a maximum stretch reflex by JM, full relaxation of homonymous muscle should be carefully confirmed.

SIGNIFICANCE

Our results provide evidence for better understanding of the features of JM and insight into its clinical application.

No association found between the type 1 sigma receptor gene polymorphisms and methamphetamine abuse in the Japanese population: a collaborative study by the Japanese Genetics Initiative for Drug Abuse

It has been suggested that individual genetic factors are involved in susceptibility to drug dependence and the manifestation of drug-induced psychosis. The aim of this study was to examine the relation between methamphetamine abusers/psychosis and the type 1 sigma receptor gene polymorphisms. Subjects comprised 143 MAP abusers and 181 healthy controls. Two polymorphisms in the type 1 sigma receptor gene, GC-241-240TT and A61C (Gln2Pro), were examined in the present study. No significant differences were observed in either polymorphism between healthy controls and MAP abusers/psychosis. In the subgroup analyses, the rate of CC genotype of A61C tended to be higher in MAP patients who had experienced spontaneous relapse without MAP use than in those who had not (P = .06, OR = 3.02 95%CI = 0.92-9.92). However, the level of this significant trend did not remain after the Bonferroni's multiple correction. This study suggests that type 1 sigma receptor gene is unlikely to play a major role in substance abuse liability and/or the development of MAP psychosis.

No association is found between the candidate genes of t-PA/plasminogen system and Japanese methamphetamine-related disorder: a collaborative study by the Japanese Genetics Initiative for Drug Abuse

In the central nervous system, tissue-plasminogen activator (t-PA)/plasmin system is involved in long-term synaptic plasticity and remodeling, and participates in rewarding effects of methamphetamine (MAP), by acutely regulating MAP-induced dopamine release in the nucleus accumbens. The aim of this study was to examine the relationships between the patients with MAP abusers/psychosis and the t-PA/plasminogen system genes. Subjects comprised 185 MAP abusers and 288 healthy controls. Four polymorphisms in the t-PA, plasminogen activator inhibitor, and plasminogen genes were examined in the present study. No significant differences were observed in each polymorphism between healthy controls and MAP abusers/psychosis. This study suggests that t-PA/plasminogen system is unlikely to be a major contributor to the substance abuse liability and/or the development of MAP psychosis.

Contralateral stenosis as a risk factor for carotid endarterectomy measured by near infrared spectroscopy

AIM

It is still controversial whether the existence of a contralateral stenosis is a risk factor during carotid endarterectomy (CEA). We used a near infrared spectroscopy (NIRS) monitoring system during CEA to evaluate the hemodynamic effect of contralateral stenosis during cross clamping of the carotid arteries.

METHODS

We monitored 34 consecutive cases of CEA, using NIRS. Tissue oxygen index (TOI), as a parameter of oxygenation, and total hemoglobin index (THI), as a parameter of blood volume, were measured during cross-clamping the carotid arteries. We evaluated the relationship between these results and the pre- and intraoperative characteristics including the existence of a contralateral stenosis and the results of single-photon emission computed tomography (SPECT).

RESULTS

Bilateral TOI and THI correlated well with the severity of the stenosis of the contralateral internal carotid artery, and ipsilateral THI correlated with the cerebrovascular reserve measured by SPECT.

CONCLUSIONS

A contralateral stenosis is a risk factor for CEA from the hemodynamical point of view, and extreme care should be taken when performing CEA in patients with bilateral stenoses.

A polymorphism of DRD2 gene and brain atrophy in methamphetamine psychosis

Our group, Ujike et al., recently reported that the A1 allele of TaqI A polymorphism of the dopamine receptor D2 (DRD2) gene, associated with transient psychosis, significantly differs from that of patients with prolonged psychosis in methamphetamine psychosis. Therefore, we examined the association between the TaqI A polymorphism of the DRD2 gene and the brain MRI view for patients with methamphetamine psychosis. The subjects underwent brain MRI scans using the FLAIR method. Genotyping was performed by PCR-RFLP methods using genomic DNA extracted from peripheral blood by the phenol method. Ten subjects had the A1/A2 genotype, eleven subjects had the A2/A2 genotype, and no subject had the A1/A1 genotype. The domain size, including the thalamus and basal ganglia that were inside each side of the putamens, did not differ between the three groups (the A1/A2-group, the A2/A2-group, and the young healthy person group). In the comparison based on this domain, the temporal lobe tended to narrow in the A2/A2-group compared to the A1/A2-group (P = .06). The other domain (cerebrum, corpus callosum, etc.) showed no difference between the A1/A2-group and the A2/A2-group. It is suggested that in methamphetamine psychosis the TaqI A polymorphism not only regulates prolongation of psychosis symptoms but also influences the form of the temporal lobe.