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.