Levels of the oxidative stress marker γ-glutamyltranspeptidase at different stages of nonalcoholic fatty liver disease

OBJECTIVES

This study investigated oxidative stress in the liver, by determining hepatic expression and serum levels of γ-glutamyltranspeptidase (GGT) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in different stages of nonalcoholic fatty liver disease (NAFLD), and assessed whether GGT can differentiate between the various stages of NAFLD.

METHODS

Expression of GGT and 8-OHdG was examined in biopsy specimens by immunohistochemistry, and serum GGT and 8-OHdG levels were measured by enzyme-linked immuno sorbent assays in patients with simple fatty liver (n = 10), nonalcoholic steatohepatitis (NASH; n = 10) and, as a control, in alcoholic liver disease (ALD; n = 10).

RESULTS

Hepatic tissue expression of GGT and 8-OHdG was seen in ALD, NASH and fatty liver patients. The percentage of hepatocytes positive for 8-OHdG expression and serum 8-OHdG levels was significantly higher in patients with NASH than simple fatty liver. Serum GGT levels were increased in all cases with ALD, NASH and fatty liver, and correlated significantly with serum levels of 8-OHdG in ALD and NASH, but not in simple fatty liver.

CONCLUSIONS

Levels of GGT in fatty liver patients may compensate for mild oxidative stress by repressing 8-OHdG levels and preventing progression to NASH; however further oxidative stress leads to increased levels of 8-OHdG and the development of NASH.

PP121. Expression of PlGF, sFlt, MTF-1, HO-1 and HIF-1 alpha mRNAs in preeclampsia placenta and effect of preeclampsia sera on their expression of choriocarcinoma cells

INTRODUCTION

Placenta growth factor (PlGF) is a growth factor originated from placenta. The sFlt-1 is soluble receptor for PlGF and suppresses PlGF function. It has been reported that in preeclampsia, serum level of PlGF decreased and sFlt-1 level increased and that preeclampsia placenta is in hypoxic condition. Metal-responsive transcription factor (MTF)-1, Hemoxigenase 1 (HO-1) and Hypoxia responsive factor -1 (HIF-1) may be induced in hypoxic condition.

OBJECTIVES

In order to investigate pathophysiology in preeclampsia, we studied the expression of PlGF, sFlt-1, MTF-1, HO-1 and HIF-1 alpha mRNAs in placenta taken from preeclampsia and the effect of preeclampsia sera on their expression of choriocarcinoma cells and analysed the effect of placental hypoxia and serum factor on the expression of PlGF and sFlt-1 mRNA.

METHODS

Placenta and serum samples were taken from preeclampsia and normal pregnancy with informed consent. The choriocarcinoma cells (JEG-3) were cultured in 24-well tissue culture plate. The cells were cultured with preeclampsia and normal pregnant sera. The RNAs were purified from these cells 24h after and placenta. The expressions of these mRNA were measured by using the real time PCR method (Applied Biosystems-7500).

RESULTS

The expression of PlGF mRNA decreased and that of sFlt-1mRNA increased in preeclampsia placenta. The expression of MTF-1 and HO-1 mRNA decreased. The correlation was found between the expression of PlGF and MTF-1 mRNA, PlGF and HO-1 mRNA and sFlt-1 and HO-1mRNA. Moreover, expression of sFlt-1mRNA increased and HO-1mRNA decreased in JEG-3 cells after incubation of preeclampsia sera.

CONCLUSION

The changes of PlGFmRNA in preeclampsia placenta may relate to the expression of MTF-1 and HO-1 mRNA. The changes of sFlt-1mRNA may relate to the expression of HO-1 mRNA and serum factor. Not only hypoxia but also serum factor may play a role of the levels of PlGF and sFlt-1 in preeclampsia placenta.

ACTN3 polymorphism affects thigh muscle area

Muscle mass is an important factor influencing the activity of daily living in older adults. We aimed to investigate whether alpha-actinin-3 (ACTN3) gene R577X polymorphism affects muscle mass in older Japanese women. A total of 109 women (mean+/-SD, 64.1+/-6.0 years) were genotyped for the R/X variant of ACTN3. Mid-thigh muscle cross-sectional area (CSA) was assessed using MRI and compared using analysis of covariance models adjusted for body weight. In addition, physical activity and protein intake were measured as the living environmental factors affecting muscle mass. The ACTN3 R577X genotype distributions of the subjects were 19, 63 and 27 for the RR, RX, and XX genotypes, respectively. No differences in physical activity and protein intake were observed among the genotypes. The XX genotype showed lower thigh muscle CSA compared with RR&RX genotype (mean+/-SEM; XX: 69.1+/-1.8 cm(2), RR&RX: 73.6+/-1.1 cm(2); p<0.05). The results of the present study suggest that ACTN3 R577X polymorphism influences muscle mass in older Japanese women.

Effect of 12 weeks of moderate-intensity resistance training on arterial stiffness: a randomised controlled trial in women aged 32-59 years

BACKGROUND

Resistance training has been increasingly incorporated into the overall exercise programme because of its effect on muscle strength, functional capacity and osteoporosis. High-intensity resistance training increases arterial stiffness. However, the effect of moderate-intensity resistance training on arterial stiffness is unknown.

OBJECTIVE

To determine whether 12 weeks of moderate-intensity resistance training increases arterial stiffness in middle-aged women.

METHODS

35 middle-aged women (age range 32 to 59 years) volunteered to participate. The subjects were randomly assigned to one of three groups: resistance training (RT) group, aerobic exercise training (AET) group or control group. The RT and AET groups performed 12 weeks of moderate-intensity resistance training or aerobic exercise training (two days/week).

RESULTS

In the RT group, one-repetition maximum strength significantly increased after the intervention. Interestingly, aortic (carotid-femoral) pulse wave velocity (PWV; an index of arterial stiffness), and peripheral (femoral-ankle) PWV did not change with moderate-intensity resistance training. In contrast, in the AET group, carotid-femoral PWV significantly decreased after the intervention. Resistance training and aerobic exercise training did not affect blood pressure.

CONCLUSIONS

This study found that moderate-intensity resistance training did not increase arterial stiffness in middle-aged women, which may have great importance for health promotion with resistance training.

Ultrastructure of Human Placental Tissue After 6h of Normoxic and Hypoxic Dual In Vitro Placental Perfusion

The dual in vitro perfusion model of human placental tissue allows the study of different aspects of placental function, such as metabolism, transport and secretion of proteohormones, cytokines and prostaglandins. The integrity of the perfused placental tissue is an important parameter to validate the perfusion system. Using light and electron microscopy, the morphology of villous tissue was examined before and after six hours of normoxic (n=10) vs. hypoxic (n=10) perfusion. An apical shift of the rough endoplasmic reticulum and occasional vacuoles were found in the syncytiotrophoblast of the terminal villi, the exchange area of the placenta. No unexpected pathological findings were seen before the perfusion experiments and only slight changes with moderate distension of the endoplasmic reticulum after 6 h of normoxic perfusion. After hypoxic perfusions, distinct ultrastructural alterations, such as oedematous villous stroma, swollen or completely destroyed cell organelles (e.g., mitochondria and endoplasmic reticulum), multiple vacuoles inside syncytio- and cytotrophoblasts as well as the microvilli were seen, which leads to an impairment of the placental barrier and other functions. The ultrastructural examination of placental tissue before and after dual in vitro perfusion broadens the knowledge of physiological and pathophysiological processes in the perfused placenta and may be a beneficial part of regular validation.

Effects of leg resistance training on arterial function in older men

BACKGROUND

Little information is available on the effect of strength training on vascular function, particularly in older people.

OBJECTIVE

To determine the effect of resistance training on arterial stiffness and endothelial function in older adults.

METHOD

Eleven healthy men (mean (SEM) age 64 (1) years) performed 12 weeks of resistance training involving knee flexion and extension (three sets a day, two days a week).

RESULTS

Resistance training increased maximal muscle power by 16% (p<0.0001). Arterial stiffness as assessed by aortic pulse wave velocity did not change with resistance training. Plasma concentration of nitric oxide (NO), measured as its stable end product (nitrite/nitrate), had increased (p<0.05) after resistance training (61.2 (10.4) v 39.6 (3.2) micromol/l). There was no change in plasma concentration of endothelin-1.

CONCLUSION

The results suggest that short term resistance training may increase NO production without stiffening central arteries in healthy older men.

A 2-year follow-up study on muscle size and dynamic strength in teenage tennis players

Growth trends in the cross-sectional area of the quadriceps femoris (CSA(QF)) and its dynamic strength in 12 teenage tennis players (six boys and six girls), aged from 10.7 to 13.2 years at the onset of the study, were investigated through a 2-year follow-up survey. CSA(QF) values at the three levels (proximal, mid, and distal to the knee joint) and dynamic torques during knee extensions at three pre-set velocities (1.05, 3.14, and 5.24 rad/s) were determined year by year, i.e., three times (T1, T2, and T3), using magnetic resonance imaging and an isokinetic dynamometer, respectively. In both genders, the CSA(QF) values at the three levels tended to increase across the measurement times, with greater gains in the boys than in the girls at the levels mid and distal to the knee joint. Among these changes, only the CSA(QF) at the level proximal to the knee joint significantly increased regardless of changes in both skeletal age and body height. The ratios of torque to the sum of CSA(QF) at the three levels (T/CSA) at 3.14 and 5.24 rad/s for the boys and at 5.24 rad/s for the girls were significantly higher in T2 and T3 than T1. Further, the relative increases in torque and T/CSA values at 3.14 and 5.24 rad/s were greater in the boys than the girls. The findings presented here indicate that young tennis players who are in the earlier stage of adolescence increase the CSA of the QF muscle beyond normally expected growth change at the level proximal to the knee joint and show a predominant development in torque generation capability during high-velocity knee extensions, with a greater gain in boys compared with girls.

Effect of spontaneous exercise on antioxidant capacity in rat muscles determined by electron spin resonance

AIMS

The effect of physical activity on antioxidant capacity in muscle remains unknown. This study investigated the effect of spontaneous exercise on antioxidant capacity in rat muscles determined by electron spin resonance (ESR), which is a technique for the direct detection of free radicals.

METHODS

Ten-week-old male Wistar rats were housed individually in cages with a running wheel. Rats were classified as high activity (HA), middle activity (MA) or low activity group (LA), based on an assessment of running distance covered over a 23-week period. After 23 weeks of housing, soleus (Sol), plantaris (Pl), gastrocnemius [deep/surface portions (GasD/GasS)] and heart (Hrt) muscles were isolated, and scavenging activity against superoxide anions (O(2)(*-)) and hydroxyl radicals (HO(*)) was determined by ESR using a spin-trap chemical. The citrate synthase (CS) activity was used as a marker of mitochondrial oxidative phosphorylation capacity.

RESULTS

Among the parameters measured, only O(2)(*-) scavenging activity in GasD significantly correlated with the running distance. The highest scavenging activity was observed in Hrt of HA rats. The O(2)(*-) scavenging activity in Pl of MA rats was significantly higher than that of LA rats. The O(2)(*-) scavenging activity of Sol and GasS was not significantly different between the three groups. Furthermore, the HO(*) scavenging activity of any muscle specimens was similar among the three groups and did not correlate with running distance at all. CS activity did not significantly differ between the three groups.

CONCLUSION

These data suggest that O(2)(*-) scavenging activity in specific types of muscle tissues would increase especially in spontaneously active animals. However, HO(*) scavenging activity would not.

Recruitment of the thigh muscles during sprint cycling by muscle functional magnetic resonance imaging

The purpose of the present study was to investigate recruitment patterns of the thigh muscles during maximal sprint cycling by muscle functional magnetic resonance imaging (mfMRI). Twelve healthy men participated in this study and performed 2, 5, and 10 sets of 6-s supramaximal cycling with a load of 7.5 % of their body weight with 0.5 min of rest between the sets. Before and immediately after the exercise, T2-weighted MR images, i.e. mfMRI, of the right-thigh were taken to calculate T2 of eleven thigh muscles. Vastus lateralis, semitendinosus, and sartorius were the highest activated, i. e. had the greatest T2 change, among the quadriceps, hamstring, and adductors, respectively, compared with other muscles. Total power output during 2, 5, and 10 sets of sprint cycling was correlated with percent change in T2 in the quadriceps correlated (r (2) = 0.507 to 0.696, p < 0.01), the hamstring (r (2) = 0.162 to 0.335, p < 0.05 approximately 0.001), and the adductor muscles (r (2) = 0.162 to 0.473, p < 0.05 approximately 0.0001). With use of stepwise regression analysis, total power output was significantly correlated with % change in T2 of the vastus medialis (VM) (p < 0.0001) and vastus intermedius (VI) (p < 0.05) (r (2) = 0.698, p < 0.0001). We concluded that eleven thigh muscles were activated non-uniformly, and that the VM and VI play a key role during maximal sprint cycling.

Effects of 12 months of exercise training on salivary secretory IgA levels in elderly subjects

BACKGROUND

The immune system declines in efficiency with advancing age, making the elderly less resistant to pathogenic microorganisms. Upper respiratory tract infection (URTI) is a common illness. Recent studies have shown that suppression of secretory immunoglobulin A (SIgA) is associated with increased incidence of URTI.

OBJECTIVE

To assess the effect of exercise on salivary SIgA in elderly subjects.

METHODS

Forty five elderly subjects (18 men, 27 women; mean (SD) age 64.9 (8.4) years) performed both 60 minute resistance and 60 minute moderate endurance training a week for 12 months. Saliva samples were obtained before training, and at four and 12 months during the training period. Salivary SIgA concentrations were measured by enzyme linked immunosorbent assay, and the SIgA secretion rate was calculated.

RESULTS

SIgA concentrations before training, and at four and 12 months during training were 24.7 (14.4), 27.2 (14.2), and 33.8 (18.5) micro g/ml respectively. SIgA secretion rates were 29.5 (26.0), 33.8 (27.2) and 46.5 (35.1) micro g/min respectively. The results indicate that both the concentration and secretion rate of SIgA significantly (p<0.01) increased during 12 months of exercise in these elderly subjects.

CONCLUSION

Regular moderate exercise seems to enhance mucosal immune function in elderly subjects.

Functional Electrical Stimulation (FES) for spinal cord injury

Restoration of respiratory motion by stimulation of the phrenic nerve was investigated. Respiratory motion was restored successfully by introducing a breathing pacemaker to a patient with respiratory disturbance due to upper cervical spinal cord injury. Breathing pacemakers are considered to be more similar to physiological conditions compared to mechanical ventilators. Although the system is very expensive, its cost effectiveness may be excellent, provided that it can be used for long hours each day over an extended period. The system is effective in improving patient QOL because it dramatically increases patient mobility. From these findings, it is concluded that breathing pacemakers should be used more frequently in Japan, and that various forms of support are necessary to cope with economic and other concerns.

Clinical and genetic studies of families with the tau N279K mutation (FTDP-17)

The tau N279K mutation was identified in four separately ascertained families in the United States, Japan, and France and in another recently discovered affected individual in Japan. The authors analyzed genealogical and clinical records and DNA samples. Average age at onset was 43 years; survival time was 7 years. All families exhibited similar clinical features, with parkinsonism, dementia, and supranuclear palsy uniformly seen. A founder effect indicated by a shared disease haplotype was seen only in two Japanese families. The N279K mutation can develop independently in different parts of the world.

Relationship between urinary symptoms and disease-related parameters in multiple sclerosis

OBJECTIVE

To find the prevalence of voiding dysfunction in patients with multiple sclerosis and to examine the relationship between the voiding dysfunction and various parameters of the disease (disease severity, disease duration, lesion site, age and sex).

METHODS

Using the International prostate symptom score, lower urinary tract symptoms were quantitatively evaluated in all patients with multiple sclerosis who had visited our neurological department during three months. The lesion site in the central nervous system was determined by a combination of neurological and magnetic resonance imaging findings.

RESULTS

Of the 47 patients who had completed the questionnaire, 25 (53 %) were considered to have symptomatic voiding dysfunction. Even at early stage of the disability, 6 of 19 (32 %) patients were symptomatic. Eight (17 %) patients had irritative urinary symptoms alone, whereas 9 (19 %) patients had obstructive urinary symptoms alone. The irritative and obstructive symptoms were concomitant in 10 (21 %) patients. Compared with reports from Western countries, the ratio of obstructive symptoms to irritative symptoms was high in Japan. The degree of irritative symptoms was well correlated with the disease severity, whereas the correlation of obstructive symptoms with the disease severity was less significant. Irritative symptoms also showed a weak correlation with the disease duration, but obstructive symptoms did not. Among the lesion sites in the central nervous system, only the presence of the spinal cord lesion was related to the degree of urinary symptoms. Urinary symptoms were not significantly influenced by the age or the sex. Quality of life was disturbed by urinary symptoms, and this disturbance paralleled the disease severity.

CONCLUSION

Urinary symptoms, especially irritative symptoms, reflect the condition of the disease. Thus, the quantified urinary symptoms may assist neurological diagnosis.

Relationship between mitochondrial DNA polymorphism and the individual differences in aerobic performance

This study focused on the mitochondrial DNA (mtDNA) as the genetic factor most likely to bring about the individual difference in endurance capacity or its trainability. Platelets contain mtDNA but no nuclear DNA, whereas rho(0)-HeLa cells have nuclear DNA but no mtDNA. The oxidative capacity of mitochondria in the cultured cells, which were fused rho(0)-HeLa cell with platelets obtained from individual subjects (the so-called "cybrids"), reflects the individual mtDNA polymorphism in the gene-coding region. The purpose of this study was to investigate the relationship between the oxidative capacity of cybrids and the individual difference in endurance capacity, or its trainability. Forty-one sedentary young males took part in an 8-week endurance training program. They were determined by using their VO(2 max) as an index of endurance capacity on an ergocycle before and after the endurance training program. The relations between VO(2 max) before endurance training or the change of it by endurance training and the oxidative capacity of cybrids were investigated. There was no relation between them, and two groups were drawn from all subjects, based on one standard division of their initial VO(2 max): the higher pre-VO(2 max) group (n = 6) and the lower pre-VO(2 max) group (n = 5) (51.8 +/- 3.5 ml/min/kg vs. 33.3 +/- 3.8 ml/min/kg, p < 0.01). No significant difference was found between the O(2) consumption of the cybrids in the higher initial VO(2 max) group and that in the lower initial VO(2 max) group (16.3 +/- 4.9 vs. 15.9 +/- 2.0 nmol O(2)/min/10(7) cells, NS). Furthermore, neither the cytochrome c oxidase (COX) activity nor the complex I + III activity of cybrids showed a significant difference between the two groups. The oxidative capacity of cybrids between the high trainability group (n = 6) (Delta VO(2 max) 12.1 +/- 1.6 ml/min/kg) and the low trainability group (n = 9) (Delta VO(2 max) 2.3 +/- 0.5 ml/min/kg) was also similar. Thus the mtDNA polymorphism is very unlikely to relate to the individual difference in endurance capacity or its trainability in young sedentary healthy subjects.

Tumor necrosis factor gene polymorphisms in patients with sporadic Parkinson's disease

We studied promoter region polymorphisms in the tumor necrosis factor (TNF) gene at position -1031, -863, and -857, in 172 Japanese patients with sporadic Parkinson's disease (PD). The frequency of the -1031C allele, a high producer of TNF, increased significantly in early onset PD patients compared with controls. In addition, PD patients with the -1031C allele showed a significantly earlier onset than those without -1031C allele, after stratification of the data by an interleukin-1beta gene polymorphism. Our findings suggest that TNF might have a toxic effect in PD.

Riluzole stimulates nerve growth factor, brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor synthesis in cultured mouse astrocytes

Riluzole is an antiexcitotoxic agent used for the treatment of amyotrophic lateral sclerosis, and reported to have neuroprotective effects in animal models of Parkinson's disease, Huntington's disease and brain ischemia. We investigated the effects of riluzole on synthesis of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) in cultured mouse astrocytes. The protein and mRNA levels were measured by enzyme-linked immunosorbent assay and semiquantitative reverse transcription-polymerase chain reaction, respectively. Treatment with riluzole at 100 microg/ml (426 microM) for 24 h increased the contents of NGF, BDNF, and GDNF in the culture medium 109-fold, 2.0-fold and 3.1-fold over the control, respectively. The drug-induced relative mRNA levels of NGF, BDNF, and GDNF were 7.3-fold at 2 h, 2.1-fold at 4 h, and 1.9-fold at 2 h, respectively. These results indicate that riluzole stimulates synthesis of NGF, BDNF and GDNF in cultured astrocytes. Riluzole might exert neuroprotective effects, at least in part, via stimulation of neurotrophic factors.

Endurance training under 2500-m hypoxia does not increase myoglobin content in human skeletal muscle

The present study was carried out to determine whether myoglobin (Mb) concentration ([Mb]) in human skeletal muscle is influenced by 8 weeks of endurance training under normal conditions, and under hypoxic conditions equivalent to an altitude of 2500 m. Fourteen healthy but sedentary male adults who did not participate in any regular exercise program took part in this study. They were divided into two groups according to the training regime to which they were submitted: the N group, who exercised under normobaric conditions, and the H group, who exercised under hypobaric conditions. All subjects performed an incremental cycling exercise at sea level to evaluate their maximal O2 uptake (VO2max) before and after the 8-week endurance training course period. Muscle tissue samples were obtained by needle biopsy from the vastus lateralis muscle for histochemical and biochemical analysis. Training induced an increase in VO2max in both the N and H groups (P < 0.05), although there was no significant difference in these changes between groups. The 8-week training had no effect on [Mb] in either group. Muscle fiber composition was also unaffected by the training course. In contrast, citrate synthase activity in both groups increased by [mean (SD)] 28.2 (33.3)% (N: P < 0.01) and 32.0 (18.2)% (H: P < 0.05) after training, and the number of capillaries (capillary:fiber ratio) increased by 47.7 (33.8)% (N: P < 0.01) and 32.3 (20.6)% (H: P < 0.05). There were no significant differences in these parameters between the N and H groups. These results suggest that significant improvement of aerobic potential as a result of endurance training are not accompanied by increases in [Mb] in human skeletal muscle. In addition, a lower absolute workload may not be sufficient to stimulate Mb synthesis in humans, even where endurance training is carried out under hypoxia.

Change in post-exercise vagal reactivation with exercise training and detraining in young men

We studied the effects of aerobic exercise training and detraining in humans on post-exercise vagal reactivation. Ten healthy untrained men trained for 8 weeks using a cycle ergometer [70% of initial maximal oxygen uptake (VO2max) for 1 h, 3-4 days.week-1] and then did not exercise for the next 4 weeks. Post-exercise vagal reactivation was evaluated as the time constant of the beat-by-beat decrease in heart rate during the 30 s (t30) immediately following 4 min exercise at 80% of ventilatory threshold (VT). The VO2max and the oxygen uptake at VT had significantly increased after the 8 weeks training programme (P < 0.0001, P < 0.001, respectively). The t30 had shortened after training, and values after 4 weeks and 8 weeks of training were significantly shorter than the initial t30 (P < 0.05, P < 0.01, respectively). The change in the t30 after 8 weeks of training closely and inversely correlated with the initial t30 (r = -0.965, P < 0.0001). The reduced t30 was prolonged significantly after 2 weeks of detraining, and had returned almost to the baseline level after a further 2 weeks of detraining. These results suggest that aerobic exercise training of moderate intensity accelerates post-exercise vagal reactivation, but that the accelerated function regresses within a few weeks of detraining.

The effects of cytoplasmic transfer of mtDNA in relation to whole-body endurance performance

The purpose of this study was to examine the relation between whole-body aerobic capacity and mitochondrial facilities. The mitochondrial enzyme system of oxidative phosphorylation (OXPHOS) is encoded both by mitochondrial DNA (mtDNA) and nuclear DNA. To identify the effect of mtDNA on whole-body aerobic capacity, we fused the platelets of the study subjects that contained mtDNA but that lacked nuclear DNA with rho(0) HeLa cells, which lacked mtDNA, and isolated repopulated cybrids. The mitochondrial respiratory functions of the cybrids, estimated from cell oxygen consumption and cytochrome-c oxidase (CCOX), were compared between endurance athletes and sedentary controls. The oxygen consumption was 18.5 +/- 3.9 and 18.2 +/- 4.1 nmol/min/ml/10(7) cells in athletes and controls, respectively. The CCOX activity was 98.8 +/- 17.5 and 116.7 +/- 9.8%, compared with fibroblasts in athletes and controls, respectively. No significant difference was noted between groups in either cell oxygen consumption or CCOX activity. These results show that the OXPHOS enzymes coded by mtDNA do not strongly influence whole-body aerobic fitness.

Postural control responses sitting on unstable board during visual stimulation

Concerning with the relation of vection induced by the optokinetic stimulation and the body movement, especially we attended to the neck joint movement, which counteracted to the shoulder movement. Then, we analyzed the mechanisms of the sitting postural control by using the seesaw board. By the optokinetic stimulation through the head mounted display (H.M.D.), the vection was leaded, and it affected to the sway of the body on the seesaw board. In this experiment, we found that the movement of upper part of body except for the head was the same direction to the seesaw board but the head moved out of phase to the seesaw board. This phenomenon will be suggested that the unstable condition of sway is balanced by the counter swing of head and the neck muscle tonus is controlled by acting of the vestibulo-collic reflex.

Effects of exercise training of 8 weeks and detraining on plasma levels of endothelium-derived factors, endothelin-1 and nitric oxide, in healthy young humans

Vascular endothelial cells produce nitric oxide (NO), which is a potent vasodilator substance and has been proposed as having antiatherosclerotic property. Vascular endothelial cells also produce endothelin-1 (ET-1), which is a potent vasoconstrictor peptide and has potent proliferating activity on vascular smooth muscle cells. Therefore, ET-1 has been implicated in the progression of atheromatous vascular disease. Because exercise training has been reported to produce an alteration in the function of vascular endothelial cells in animals, we hypothesized that exercise training influences the production of NO and ET-1 in humans. The purpose of the present study was to examine whether chronic exercise could influence the plasma levels of NO (measured as the stable end product of NO, i.e., nitrite/nitrate [NOx]) and ET-1 in humans. Eight healthy young subjects (20.3 +/- 0.5 yr old) participated in the study and exercised by cycling on a leg ergometer (70% VO2max for 1 hour, 3-4 days/week) for 8 weeks. Venous plasma concentrations of NOx and ET-1 were measured before and after (immediately before the end of 8-week exercise training) the exercise training, and also after the 4th and 8th week after the cessation of training. The VO2max significantly increased after exercise training. After the exercise training, the plasma concentration of NOx significantly increased (30.69 +/- 3.20 vs. 48.64 +/- 8.16 micromol/L, p < 0.05), and the plasma concentration of ET-1 significantly decreased (1.65 +/- 0.14 vs. 1.23 +/- 0.12 pg/mL, p < 0.05). The increase in NOx level and the decrease in ET-1 level lasted to the 4th week after the cessation of exercise training and these levels (levels of NOx and ET-1) returned to the basal levels (the levels before the exercise training) in the 8th week after the cessation of exercise training. There was a significant negative correlation between plasma NOx concentration and plasma ET-1 concentration. The present study suggests that chronic exercise causes an increase in production of NO and a decrease in production of ET-1 in humans, which may produce beneficial effects (i.e., vasodilative and antiatherosclerotic) on the cardiovascular system.

Influence of interleukin-1beta gene polymorphism on age-at-onset of spinocerebellar ataxia 6 (SCA6) in Japanese patients

An inverse correlation is observed between the expanded CAG repeat number and age-at-onset of spinocerebellar ataxia 6 (SCA6). To detect another modifying genetic factor for SCA6, we studied polymorphisms in the genes for interleukin (IL)-1beta and tumor necrosis factor in 122 Japanese patients with SCA6. No contribution of these polymorphisms to the variance in disease onset was observed by regression analysis or by ANOVA. The IL-1beta promoter polymorphism, however, significantly affected the age-at-onset, when adjusted for the CAG repeat number as a covariate (P=0.0004, by ANCOVA), suggesting that IL-1beta may be a genetic factor other than the SCA6 gene that modifies the age-at-onset of the disease.

Glial cell line-derived neurotrophic factor in the substantia nigra from control and parkinsonian brains

Glial cell line-derived neurotrophic factor (GDNF) was measured for the first time in the brain (substantia nigra, caudate nucleus, putamen, cerebellum, and frontal cortex) from control and parkinsonian patients by highly sensitive sandwich enzyme-linked immunosorbent assay. In both groups, the levels of GDNF in the various brain regions were lower (pg/mg protein) than those of brain-derived growth factor (ng/mg order), and were significantly higher in the nigro-striatal dopaminergic regions (substantia nigra, caudate nucleus, putamen) than in the cerebellum and frontal cortex (P < 0.05). However, the content of GDNF in the dopaminergic regions showed no significant difference between parkinsonian and control patients.

Muscle function in 164 men and women aged 20--84 yr

PURPOSE

The purpose of the present study was to investigate the effect of aging in men and women on muscle functional properties, i.e., muscle force and force per unit of cross-sectional area (force/CSA).

METHODS

A total of 164 volunteers participated in this study and were divided into five groups according to their chronological age as follows: 20s (20--39 yr old), 40s, 50s, 60s, and 70s (70--84 yr old). Isokinetic (0, 60, 180, and 300 degrees.s(-1)) knee extensor and flexor peak torque, and CSA of the quadriceps femoris (QF) muscle of the mid-thigh were measured.

RESULTS

Peak torque during knee extension and flexion was inversely related to age in both men and women. This was the case irrespective of the speed of contraction in both genders (men: r = -0.797 to -0.756, all P < 0.001, women: r = -0.639 to -0.530, all P < 0.001). A significant correlation was observed between CSA of QF and peak torque during isometric knee extension in men (r = 0.827, P < 0.001) and women (r = 0.657, P < 0.001). During isometric contraction, the force/CSA exhibited a significant decrease with increasing age in men (r = -0.518, P < 0.001) but not in women (r = -0.207, NS).

CONCLUSION

These results thus suggest that muscle strength losses would be mainly due to a decline in muscle mass in both genders, whereas age-related decline in muscle function in men may also be the result of neural factors, such as muscle recruitment and/or specific tension.

Selegiline and desmethylselegiline stimulate NGF, BDNF, and GDNF synthesis in cultured mouse astrocytes

We investigated the effects of selegiline and desmethylselegiline on synthesis of neurotrophic factors in cultured mouse astrocytes. Treatment with 2 mM selegiline for 24 h increased the contents of NGF, BDNF, and GDNF in the culture medium 26-, 1.7-, and 4.2-fold over the control, respectively. With this drug the maximum relative mRNA levels of NGF, BDNF, and GDNF were 6.2-fold at 2 h, 3.4-fold at 6 h, and 2.7-fold at 2 h, respectively. Selegiline at 0.2 mM completely inhibited the MAO activity, but had no effect on the content of neurotrophic factors, suggesting that stimulation of neurotrophic factors by selegiline is independent of MAO-B inhibition. Desmethylselegiline at 1.68 mM for 24 h elevated the NGF, BDNF, and GDNF contents 4.1-, 1.7-, and 2.4-fold over the control, respectively; and the relative transcript levels of NGF, BDNF, and GDNF reached 2.6-fold at 2 h, 1.7-fold at 6 h, and 1.8-fold at 2 h, respectively. These findings suggest that selegiline and desmethylselegiline may protect neurons by up-regulating endogenous NGF, BDNF, and GDNF synthesis.

Effects of aging on EMG variables during fatiguing isometric contractions

The purpose of this study was to evaluate the neuromuscular adaptation that occurred with aging, by comparing young and aged subjects with respect to changes in surface EMG from the tibialis anterior muscle during fatiguing contractions. EMG variables such as the averaged rectified value (ARV), median frequency (MDF), and muscle fiber conduction velocity (MFCV) were calculated during maximal (MVC, 3 sec) and submaximal (60% MVC, 60 sec) isometric contractions. Muscular force, ARV, MDF, and MFCV during MVC were significantly greater in the young than in the elderly (p < 0.05). EMG amplitude increased and the waveform slowed in all subjects during submaximal contractions, indicating the development of local muscle fatigue. As fatigue progressed, the ARV increased and the MDF and MFCV decreased significantly (p < 0.01). The fatigue-induced changes in the MDF and MFCV were significantly smaller in aged than in young subjects (p < 0.05), a trend also seen in the ARV change, which means that the elderly cannot be fatigued as much as the young with contractions of the same relative intensity. These results as a whole suggest that the aged subjects hold an adaptive motor strategy to cope with age-related neuromuscular deteriorations, due to the decline of motor unit activation and selective atrophy of fast twitch muscle fibers.

The use of magnetic resonance images to investigate the influence of recruitment on the relationship between torque and cross-sectional area in human muscle

The purpose of the present study was to investigate the effect of recruitment on the relationship between peak torque and physiological cross-sectional area (PCSA) in human muscle. A group of 11 healthy men participated in this study. Isokinetic knee extension torques at seven (0, 30, 60, 120, 180, 240, and 300 degrees x s(-1)) velocities were determined. Magnetic resonance imaging (MRI) was performed to calculate PCSA of right quadriceps femoris (QF) muscle. Exercise-induced contrast shifts in spin-spin relaxation time (T2)-weighted MRI were taken at rest and immediately after repetitive knee-extension exercise and T2 of QF were calculated. The MRI pixels with T2 values more than 1 SD greater than the means at rest were considered to represent QF muscle that had contracted. The area of activated PCSA within the total in QF was expressed as percentage activated PCSA and used as an index of muscle recruitment. The PCSA correlated with peak torque at 0 degree x s(-1) (r = 0.615, P<0.05); in contrast, activated PCSA correlated with peak torque at 120 degrees x s(-1) (r = 0.603, P<0.05) and 180 degrees x s(-1) (r = 0.606, P<0.05). Additionally, there was a significant difference in correlation coefficients between the activated PCSA-peak torque relationship and the PCSA-torque relationship (P<0.05). These results suggested that muscle recruitment affects the PCSA-torque relationship.

Voiding dysfunction and Parkinson's disease: urodynamic abnormalities and urinary symptoms

PURPOSE

We evaluated bladder dysfunction and Parkinson's disease in regard to disease severity and determined whether subjective patient urinary symptoms correlated with urodynamic abnormalities.

MATERIALS AND METHODS

We assessed bladder dysfunction in 70 patients with Parkinson's disease and urinary symptoms using the International Prostate Symptom Score and urodynamic tests.

RESULTS

Urodynamic evaluation revealed detrusor hyperreflexia in 47 patients (67%), hyporeflexia or areflexia in 11 (16%), hyperreflexia with impaired contractile function in 6 (9%), hyperreflexia with detrusor-sphincter dyssynergia in 2 (3%) and normal function in 4 (6%). The incidence of urodynamic abnormalities appeared to increase with disease severity. However, the only urodynamic parameter that correlated with disease severity was post-void residual urine volume. On the other hand, symptom index scores increased with disease severity. The irritative symptom score correlated with maximum cystometric capacity and volume at initial desire to void, whereas the obstructive symptom score correlated with post-void residual urine volume. Also, irritative and obstructive scores were good predictors of overactivity during the storage and underactivity at the voiding phases.

CONCLUSIONS

Bladder function may deteriorate progressively with advancing disease. Symptom scores are fairly accurate for predicting likely urodynamic abnormalities. Our results imply that quantifying subjective urinary symptoms is useful for estimating the severity and type of bladder dysfunction.

Caspase activities and tumor necrosis factor receptor R1 (p55) level are elevated in the substantia nigra from parkinsonian brain

The activities of caspase-1 and caspase-3 were measured by use of fluoropeptides as substrates for the first time in the brain (substantia nigra, caudate nucleus, putamen, cerebellum, and frontal cortex) from control and parkinsonian patients. The activities of caspases in the brain were significantly higher in the substantia nigra from parkinsonian patients than those in the brain from control patients (p < 0.01). However, the activities of caspases in the caudate nucleus, putamen, cerebellum, and frontal cortex showed no significant difference between parkinsonian and control patients. The tumor necrosis factor (TNF) receptor R1 (TNF-R1, p55) level was also elevated in the substantia nigra of the parkinsonian brain in comparison with that of controls (p < 0.05). Since both caspases and TNF-R1 may play important roles in apoptotic cell death through TNF-alpha-induced signaling pathway, our present data suggest the presence of a proapoptotic environment in the substantia nigra of parkinsonian brain, probably inducing vulnerability of neurons and glias towards a variety of noxious factors.

Body sway induced by depth linear vection in reference to central and peripheral visual field

PURPOSE

A significant correlation between the magnitude of linear vection and the degree of body sway induced by a visual stimulus perceived as moving in depth was previously described (Jpn J Physiol 49: 417-424, 1999). The purpose of this study was to examine the role of the central and peripheral visual fields in inducing vection and body sway.

METHODS

Ten healthy volunteer students who had no vestibular or neurological disorders served as subjects. A depth optokinetic stimulus (DOKS) was projected onto a head-mounted display (HMD) and was perceived to move in depth. Different amounts of the central or peripheral visual field were masked independently. The magnitude of the linear vection induced by the DOKS was evaluated by verbal assessment and compared with the magnitude of induced body sway. Body sway was monitored by a video-motion-analyzer that recorded the movement of the head, shoulder, hip, knee and ankle.

RESULTS

The magnitude of vection was correlated with the frequency of DOKS and also with the amplitude of body sway (r = 0.74). When the central visual field was restricted by 10 to 30%, there was almost no change in the induced body sway and vection. However, when central occlusion was greater than 40%, depth perception and induced body movement were greatly reduced. With increasing amounts of peripheral field occlusion from 50 to 90%, there was a greater reduction of both vection and body sway.

CONCLUSION

Vection is strongly correlated with body movement, and vection and body sway were more dependent on stimulation of the peripheral visual field.

Apomorphine up-regulates NGF and GDNF synthesis in cultured mouse astrocytes

Apomorphine, a D1/D2 dopamine agonist, is an anti-parkinsonian drug. We examined the effects of apomorphine on synthesis of neurotrophic factors in cultured mouse astrocytes. After 24 h incubation with apomorphine, NGF and GDNF contents in the culture medium increased to 122-fold and 1.8-fold of the control, respectively; whereas the BDNF content did not change significantly. In Northern blot analysis, expression of NGF mRNA in astrocytes reached the maximum level at 6 h after addition of the drug. By semiquantitative RT-PCR analysis, the GDNF transcript level was found to reach 2.9-fold of the control level at 15 h. These results suggest that apomorphine may exert neuroprotective effects by stimulation of NGF and GDNF synthesis in astrocytes.

Influence of interleukin-1beta gene polymorphisms on age-at-onset of sporadic Parkinson's disease

We studied genetic polymorphisms in the promoter region (position -511) and exon 5 (position +3953) of the interleukin (IL)-1beta gene in 122 Japanese patients with Parkinson's disease (PD) and 112 controls. We also examined polymorphisms in the IL-1alpha and the IL-1 receptor antagonist genes. No significant difference was found in these genetic markers between PD patients and controls. However, PD patients with homozygotes for allele 1 at position -511 of the IL-1beta gene (IL-1B-511*1), a low producer of IL-1beta, were significantly earlier in the disease onset than those with the IL-1B-511*2 homozygotes, a high producer of IL-1beta. This suggests that IL-1beta might play a role, possibly a protective effect for dopaminergic neurons, in PD. Further population and functional studies are necessary to clarify the role of IL-1beta in PD patients.

Assessment of voiding dysfunction in Parkinson's disease by the international prostate symptom score

OBJECTIVES

To find the incidence of voiding dysfunction in Parkinson's disease and to examine the relation between the voiding dysfunction and various indices of the disease (disease severity, disease duration, age, sex, and treatment with antiparkisonian drugs), the presence of voiding dysfunction was quantitatively estimated in patients sampled on the unselected (consecutive) basis.

METHODS

Using the international prostate symptom score, lower urinary tract symptoms were quantitatively evaluated in all patients with Parkinson's disease visiting this neurological clinic during 1 month.

RESULTS

Of the 203 patients who had completed the questionnaire, 55 (27%) were considered to have symptomatic voiding dysfunction. The degree of lower urinary tract symptoms in these patients was well correlated with the severity of the disease rather than with the disease duration or the age. Thirty three (16%) patients had irritative symptoms alone, whereas three (1.5%) patients had obstructive symptoms alone. The irritative and obstructive symptoms were concomitant in 13 (6%) patients. Quality of life was disturbed by lower urinary tract symptoms, and this disturbance paralleled the severity of the disease. The influence of antiparkisonian drugs on the lower urinary tract symptoms was uncertain. The incidence of lower urinary tract symptoms seemed to be independent of sex, but obstructive symptoms were prevalent in male patients.

CONCLUSIONS

This study suggests that voiding dysfunction in patients with Parkinson's disease progressively develops at advanced stages (> or =Hoehn and Yahr stage 3 of the disability). The International prostate symptom score is useful in evaluating the voiding dysfunction of neurodegenerative disease in both men and women, not only reflecting prostatic symptoms.

Postural adjustment response to depth direction moving patterns produced by virtual reality graphics

PURPOSE

Human posture is controlled by a combination of vestibular, somatosensory and visual information. This paper is concerned with postural readjustment responses induced by vection. In the visual control of posture, visually-induced perception of self-motion plays an important role and is called vection. Vection is difficult to measure quantitatively because it is a highly subjective phenomenon.

HYPOTHESIS

An optokinetic stimulus that moves in depth induces vection. We hypothesize that the magnitude of the visually-induced body sway is correlated with the degree of vection.

METHODS

A depth optokinetic stimulus (DOKS) was projected onto a head-mounted display (HMD) worn by standing subjects. The DOKS consisted of a random dot pattern that was perceived three-dimensionally and moved in depth sinusoidally. Vection was estimated in two ways, a verbal assessment and a joystick maneuver. In addition, visually-induced body sway was measured by monitoring five reference points on the body by two video-motion analyzers.

RESULTS

The magnitude of the subjective vection was highly correlated with visually-induced body sway and was strongly dependent on the velocity of the visual stimulus. The ankle joint was pivoted during visually-induced body sway and acted as a motion initiator. When the magnitude of body sway was large, the body movement was adjusted at the hip and head-neck joints.

CONCLUSIONS

The high correlation between vection and body sway suggests that vection can be estimated quantitatively by measuring visually-induced body sway.

A mutation in the microtubule-associated protein tau in pallido-nigro-luysian degeneration

We detected a missense mutation in exon 10 of tau that causes a substitution at codon 279 (N279K) in a Japanese patient with a familial background of parkinsonism and dementia originally described as pallido-nigro-luysian degeneration. This mutation is the same as one seen in a Caucasian family with pallido-ponto-nigral degeneration. The similarities between these two families suggest a common genetic mechanism that may account for the peculiar distribution of neuroglial degeneration with tauopathy.