Effects of 1,25(OH)2 D3 and 25(OH)D3 on C2C12 Myoblast Proliferation, Differentiation, and Myotube Hypertrophy.

An adequate vitamin D status is essential to optimize muscle strength. However, whether vitamin D directly reduces muscle fiber atrophy or stimulates muscle fiber hypertrophy remains subject of debate. A mechanism that may affect the role of vitamin D in the regulation of muscle fiber size is the local conversion of 25(OH)D to 1,25(OH)2 D by 1α-hydroxylase. Therefore, we investigated in a murine C2C12 myoblast culture whether both 1,25(OH)2 D3 and 25(OH)D3 affect myoblast proliferation, differentiation, and myotube size and whether these cells are able to metabolize 25(OH)D3 and 1,25(OH)2 D3 . We show that myoblasts not only responded to 1,25(OH)2 D3 , but also to the precursor 25(OH)D3 by increasing their VDR mRNA expression and reducing their proliferation. In differentiating myoblasts and myotubes 1,25(OH)2 D3 as well as 25(OH)D3 stimulated VDR mRNA expression and in myotubes 1,25(OH)2 D3 also stimulated MHC mRNA expression. However, this occurred without notable effects on myotube size. Moreover, no effects on the Akt/mTOR signaling pathway as well as MyoD and myogenin mRNA levels were observed. Interestingly, both myoblasts and myotubes expressed CYP27B1 and CYP24 mRNA which are required for vitamin D3 metabolism. Although 1α-hydroxylase activity could not be shown in myotubes, after treatment with 1,25(OH)2 D3 or 25(OH)D3 myotubes showed strongly elevated CYP24 mRNA levels compared to untreated cells. Moreover, myotubes were able to convert 25(OH)D3 to 24R,25(OH)2 D3 which may play a role in myoblast proliferation and differentiation. These data suggest that skeletal muscle is not only a direct target for vitamin D3 metabolites, but is also able to metabolize 25(OH)D3 and 1,25(OH)2 D3 . J. Cell. Physiol. 231: 2517-2528, 2016. © 2016 The Authors. Journal of Cellular Physiology Published by Wiley Periodicals, Inc.

Regulation of myoglobin in hypertrophied rat cardiomyocytes in experimental pulmonary hypertension.

A major problem in chronic heart failure is the inability of hypertrophied cardiomyocytes to maintain the required power output. A Hill-type oxygen diffusion model predicts that oxygen supply is limiting in hypertrophied cardiomyocytes at maximal rates of oxygen consumption and that this limitation can be reduced by increasing the myoglobin (Mb) concentration. We explored how cardiac hypertrophy, oxidative capacity, and Mb expression in right ventricular cardiomyocytes are regulated at the transcriptional and translational levels in an early stage of experimental pulmonary hypertension, in order to identify targets to improve the oxygen supply/demand ratio. Male Wistar rats were injected with monocrotaline to induce pulmonary hypertension (PH) and right ventricular heart failure. The messenger RNA (mRNA) expression levels per nucleus of growth factors insulin-like growth factor-1Ea (IGF-1Ea) and mechano growth factor (MGF) were higher in PH than in healthy controls, consistent with a doubling in cardiomyocyte cross-sectional area (CSA). Succinate dehydrogenase (SDH) activity was unaltered, indicating that oxidative capacity per cell increased. Although the Mb protein concentration was unchanged, Mb mRNA concentration was reduced. However, total RNA per nucleus was about threefold higher in PH rats versus controls, and Mb mRNA content expressed per nucleus was similar in the two groups. The increase in oxidative capacity without an increase in oxygen supply via Mb-facilitated diffusion caused a doubling of the critical extracellular oxygen tension required to prevent hypoxia (PO2crit). We conclude that Mb mRNA expression is not increased during pressure overload-induced right ventricular hypertrophy and that the increase in myoglobin content per myocyte is likely due to increased translation. We conclude that increasing Mb mRNA expression may be beneficial in the treatment of experimental PH.

Single muscle fibre contractile properties differ between body-builders, power athletes and control subjects.

NEW FINDINGS: What is the central question of this study? Do the contractile properties of single muscle fibres differ between body-builders, power athletes and control subjects? What is the main finding and its importance? Peak power normalized for muscle fibre volume in power athletes is higher than in control subjects. Compared with control subjects, maximal isometric tension (normalized for muscle fibre cross-sectional area) is lower in body-builders. Although this difference may be caused in part by an apparent negative effect of hypertrophy, these results indicate that the training history of power athletes may increase muscle fibre quality, whereas body-building may be detrimental. We compared muscle fibre contractile properties of biopsies taken from the vastus lateralis of 12 body-builders (BBs; low- to moderate-intensity high-volume resistance training), six power athletes (PAs; high-intensity, low-volume combined with aerobic training) and 14 control subjects (Cs). Maximal isotonic contractions were performed in single muscle fibres, typed with SDS-PAGE. Fibre cross-sectional area was 67 and 88% (P < 0.01) larger in BBs than in PAs and Cs, respectively, with no significant difference in fibre cross-sectional area between PAs and Cs. Fibres of BBs and PAs developed a higher maximal isometric tension (32 and 50%, respectively, P < 0.01) than those of Cs. The specific tension of BB fibres was 62 and 41% lower than that of PA and C fibres (P < 0.05), respectively. Irrespective of fibre type, the peak power (PP) of PA fibres was 58% higher than that of BB fibres (P < 0.05), whereas BB fibres, despite considerable hypertrophy, had similar PP to the C fibres. This work suggests that high-intensity, low-volume resistance training with aerobic exercise improves PP, while low- to moderate-intensity high-volume resistance training does not affect PP and results in a reduction in specific tension. We postulate that the decrease in specific tension is caused by differences in myofibrillar density and/or post-translational modifications of contractile proteins.

The contribution of PFAS to thyroid hormone-displacing activity in Dutch waters: A comparison between two in vitro bioassays with chemical analysis.

Per- and polyfluoroalkyl substances (PFAS) are a group of xenobiotics that are widely distributed throughout the aquatic environment. Many PFAS are possible thyroid hormone (TH) system disrupting compounds, because they have the capacity to -amongst other- inhibit the TH thyroxine (T4) from binding to its transport protein transthyretin (TTR). This study investigated the occurrence of TH-displacing activity in the Dutch water cycle, and more specifically, the contribution of PFAS to this effect. Over one year of monitoring data of 29 PFAS (linear and branched) showed the continuous presence of PFAS in drinking waters and their surface water sources. Secondly, the FITC-T4 and TTR-TRß-CALUX bioassays were mutually compared using positive (HPLC-grade water spiked with PFOA) and negative control samples (HPLC-grade water), as well as relative potency factors (RPFs) of up to 20 PFAS congeners. Both assays were found to be suitable for measuring TH-displacing activity in water samples. As a third aim, a field study was performed in the Dutch water cycle that was comprised of samples from drinking water, surface water, PFAS contaminated sites, and 2 wastewater treatment plants. All samples were analyzed with 1. chemical analysis for 29 PFAS, 2. the FITC-T4 bioassay, and 3. the TTR-TRß-CALUX bioassay. The bioassays mutually showed good correlation (R2 0.85). Bioanalytical equivalent concentrations (BEQ) based on chemically-determined concentrations and RPFs (BEQchem) revealed that analyzed PFAS only explained ≤4.1 % of their activity in water extracts measured by both bioassays (BEQbio). This indicated that as yet unknown compounds contribute to the majority of the measured TH-displacing activity. Moreover, water treatment processes (e.g. DW production from SW) showed a larger contribution of target PFAS to the BEQbio. This could be a first lead to identify unknown compounds that contribute to this activity, and as such, enable the assessment of possible risks associated by the occurrence of TH-displacing activity in water.

The relationship between quantitative magnetic resonance imaging of the ankle plantar flexors, muscle function during walking and maximal strength in people with neuromuscular diseases.

BACKGROUND: Progression of plantar flexor weakness in neuromuscular diseases is usually monitored by muscle strength measurements, although they poorly relate to muscle function during walking. Pathophysiological changes such as intramuscular adipose tissue affect dynamic muscle function independent from isometric strength. Diffusion tensor imaging and T2 imaging are quantitative MRI measures reflecting muscular pathophysiological changes, and are therefore potential biomarkers to monitor plantar flexor functioning during walking in people with neuromuscular diseases. METHODS: In fourteen individuals with plantar flexor weakness diffusion tensor imaging and T2 scans of the plantar flexors were obtained, and the diffusion indices fractional anisotropy and mean diffusivity calculated. With a dynamometer, maximal isometric plantar flexor strength was measured. 3D gait analysis was used to assess maximal ankle moment and power during walking. FINDINGS: Fractional anisotropy, mean diffusivity and T2 relaxation time all moderately correlated with maximal plantar flexor strength (r > 0.512). Fractional anisotropy and mean diffusivity were not related with ankle moment or power (r < 0.288). T2 relaxation time was strongly related to ankle moment (r = -0.789) and ankle power (r = -0.798), and moderately related to maximal plantar flexor strength (r < 0.600). INTERPRETATION: In conclusion, T2 relaxation time, indicative of multiple pathophysiological changes, was strongly related to plantar flexor function during walking, while fractional anisotropy and mean diffusivity, indicative of fiber size, only related to maximal plantar flexor strength. This indicates that these measures may be suitable to monitor muscle function and gain insights into the pathophysiological changes underlying a poor plantar flexor functioning during gait in people with neuromuscular diseases.

Is the myonuclear domain size fixed?

It has been suggested that the number of myonuclei in a muscle fibre changes in proportion to the change in fibre size, resulting in a constant myonuclear domain size, defined as the cytoplasmic volume per myonucleus. The myonuclear domain size varies, however, between fibre types and is inversely related with the oxidative capacity of a fibre. Overall, the observations of an increase in myonuclear domain size during both maturational growth and overload-induced hypertrophy, and the decrease in myonuclear domain size during disuse- and ageing-associated muscle atrophy suggest that the concept of a constant myonuclear domain size needs to be treated cautiously. It also suggests that only when the myonuclear domain size exceeds a certain threshold during growth or overload-induced hypertrophy acquisition of new myonuclei is required for further fibre hypertrophy.

The muscle fiber type-fiber size paradox: hypertrophy or oxidative metabolism?

An inverse relationship exists between striated muscle fiber size and its oxidative capacity. This relationship implies that muscle fibers, which are triggered to simultaneously increase their mass/strength (hypertrophy) and fatigue resistance (oxidative capacity), increase these properties (strength or fatigue resistance) to a lesser extent compared to fibers increasing either of these alone. Muscle fiber size and oxidative capacity are determined by the balance between myofibrillar protein synthesis, mitochondrial biosynthesis and degradation. New experimental data and an inventory of critical stimuli and state of activation of the signaling pathways involved in regulating contractile and metabolic protein turnover reveal: (1) higher capacity for protein synthesis in high compared to low oxidative fibers; (2) competition between signaling pathways for synthesis of myofibrillar proteins and proteins associated with oxidative metabolism; i.e., increased mitochondrial biogenesis via AMP-activated protein kinase attenuates the rate of protein synthesis; (3) relatively higher expression levels of E3-ligases and proteasome-mediated protein degradation in high oxidative fibers. These observations could explain the fiber type-fiber size paradox that despite the high capacity for protein synthesis in high oxidative fibers, these fibers remain relatively small. However, it remains challenging to understand the mechanisms by which contractile activity, mechanical loading, cellular energy status and cellular oxygen tension affect regulation of fiber size. Therefore, one needs to know the relative contribution of the signaling pathways to protein turnover in high and low oxidative fibers. The outcome and ideas presented are relevant to optimizing treatment and training in the fields of sports, cardiology, oncology, pulmonology and rehabilitation medicine.

Charge exchange recombination spectroscopy at Wendelstein 7-X.

The Charge Exchange Recombination Spectroscopy (CXRS) diagnostic has become a routine diagnostic on almost all major high temperature fusion experimental devices. For the optimized stellarator Wendelstein 7-X (W7-X), a highly flexible and extensive CXRS diagnostic has been built to provide high-resolution local measurements of several important plasma parameters using the recently commissioned neutral beam heating. This paper outlines the design specifics of the W7-X CXRS system and gives examples of the initial results obtained, including typical ion temperature profiles for several common heating scenarios, toroidal flow and radial electric field derived from velocity measurements, beam attenuation via beam emission spectra, and normalized impurity density profiles under some typical plasma conditions.

Region-specific adaptations in determinants of rat skeletal muscle oxygenation to chronic hypoxia.

Chronic exposure to hypoxia is associated with muscle atrophy (i.e., a reduction in muscle fiber cross-sectional area), reduced oxidative capacity, and capillary growth. It is controversial whether these changes are muscle and fiber type specific. We hypothesized that different regions of the same muscle would also respond differently to chronic hypoxia. To investigate this, we compared the deep (oxidative) and superficial (glycolytic) region of the plantaris muscle of eight male rats exposed to 4 wk of hypobaric hypoxia (410 mmHg, Po(2): 11.5 kPa) with those of nine normoxic rats. Hematocrit was higher in chronic hypoxic than control rats (59% vs. 50%, P < 0.001). Using histochemistry, we observed 10% fiber atrophy (P < 0.05) in both regions of the muscle but no shift in the fiber type composition and myoglobin concentration of the fibers. In hypoxic rats, succinate dehydrogenase (SDH) activity was elevated in fibers of each type in the superficial region (25%, P < 0.05) but not in the deep region, whereas in the deep region but not the superficial region the number of capillaries supplying a fiber was elevated (14%, P < 0.05). Model calculations showed that the region-specific alterations in fiber size, SDH activity, and capillary supply to a fiber prevented the occurrence of anoxic areas in the deep region but not in the superficial region. Inclusion of reported acclimatization-induced increases in mean capillary oxygen pressure attenuated the development of anoxic tissue areas in the superficial region of the muscle. We conclude that the determinants of tissue oxygenation show region-specific adaptations, resulting in a marked differential effect on tissue Po(2).

Adaptations in muscle oxidative capacity, fiber size, and oxygen supply capacity after repeated-sprint training in hypoxia combined with chronic hypoxic exposure.

In this study, we investigate adaptations in muscle oxidative capacity, fiber size and oxygen supply capacity in team-sport athletes after six repeated-sprint sessions in normobaric hypoxia or normoxia combined with 14 days of chronic normobaric hypoxic exposure. Lowland elite field hockey players resided at simulated altitude (≥14 h/day at 2,800-3,000 m) and performed regular training plus six repeated-sprint sessions in normobaric hypoxia (3,000 m; LHTLH; n = 6) or normoxia (0 m; LHTL; n = 6) or lived at sea level with regular training only (LLTL; n = 6). Muscle biopsies were obtained from the m. vastus lateralis before (pre), immediately after (post-1), and 3 wk after the intervention (post-2). Changes over time between groups were compared, including likelihood of the effect size (ES). Succinate dehydrogenase activity in LHTLH largely increased from pre to post-1 (~35%), likely more than LHTL and LLTL (ESs = large-very large), and remained elevated in LHTLH at post-2 (~12%) vs. LHTL (ESs = moderate-large). Fiber cross-sectional area remained fairly similar in LHTLH from pre to post-1 and post-2 but was increased at post-1 and post-2 in LHTL and LLTL (ES = moderate-large). A unique observation was that LHTLH and LHTL, but not LLTL, improved their combination of fiber size and oxidative capacity. Small-to-moderate differences in oxygen supply capacity (i.e., myoglobin and capillarization) were observed between groups. In conclusion, elite team-sport athletes substantially increased their skeletal muscle oxidative capacity, while maintaining fiber size, after only 14 days of chronic hypoxic residence combined with six repeated-sprint training sessions in hypoxia. NEW & NOTEWORTHY Our novel findings show that elite team-sport athletes were able to substantially increase the skeletal muscle oxidative capacity in type I and II fibers (+37 and +32%, respectively), while maintaining fiber size after only 14 days of chronic hypoxic residence combined with six repeated-sprint sessions in hypoxia. This increase in oxidative capacity was superior to groups performing chronic hypoxic residence with repeated sprints in normoxia and residence at sea level with regular training only.

Compatibility of a bivalent modified-live vaccine against Bordetella bronchiseptica and CPiV, and a trivalent modified-live vaccine against CPV, CDV and CAV-2.

Eight puppies (group 1) were vaccinated once with a bivalent modified-live vaccine against infectious tracheobronchitis by the intranasal route and at the same time with an injectable trivalent vaccine against canine parvovirus, canine distemper virus and canine adenovirus; a second group of eight puppies (group 2) was vaccinated only with the intranasal bivalent vaccine, and a further eight puppies (group 3) were vaccinated only with the injectable trivalent vaccine. Three weeks later they were all challenged with wildtype Bordetella bronchiseptica and canine parainfluenza virus by the aerosol route, and their antibody responses to the five vaccine organisms were determined. Oronasal swabs were taken regularly before and after the challenge for the isolation of bacteria and viruses, and the puppies were observed for clinical signs for three weeks after the challenge. There were no significant differences in the puppies' titres against canine parvovirus, canine distemper virus and canine adenovirus type 2 between the groups vaccinated with or without the bivalent intranasal vaccine. After the challenge the mean clinical scores of the two groups vaccinated with the intranasal vaccine were nearly 90 per cent lower (P=0.001) than the mean score of the group vaccinated with only the trivalent injectable vaccine, and the puppies in this group all became culture-positive for B bronchiseptica and canine parainfluenza virus. There were only small differences between the rates of isolation of B bronchiseptica from groups 1, 2 and 3, but significantly lower yields of canine parainfluenza virus were isolated from groups 1 and 2 than from group 3.

Initial operation of a newly developed multichord motional Stark effect diagnostic in KSTAR.

A photo-elastic modulator based 25-chord motional Stark effect (MSE) diagnostic has been successfully developed and commissioned in Korea Superconducting Tokamak Advanced Research. The diagnostic measures the radial magnetic pitch angle profile of the Stark splitting of a D-alpha line at 656.1 nm by the electric field associated with the neutral deuterium heating beam. A tangential view of the neutral beam provides a good spatial resolution of 1-3 cm for covering the major radius from 1.74 m to 2.28 m, and the time resolution is achieved at 10 ms. An in-vessel calibration before the vacuum closing as well as an in situ calibration during the tokamak operation was performed by means of specially designed polarized lighting sources. In this work, we present the final design of the installed MSE diagnostic and the first results of the commissioning.

Healing of the aponeurosis during recovery from aponeurotomy: morphological and histological adaptation and related changes in mechanical properties.

Aponeurotomy, which is the transection of an aponeurosis perpendicular to its length, is performed to lengthen spastic and/or short muscles. During recovery, the cut ends of the aponeurosis are reconnected by new connective tissue bridging both ends. The aim of this study is to investigate the histological features of this new connective tissue as well as its mechanical properties after recovery from aponeurotomy. For this purpose, aponeurotomy was performed on the proximal aponeurosis of rat m. gastrocnemius medialis (GM), which was followed by six weeks of recovery. The lengths of aponeurotic tissues were measured as a function of active muscle length. The results are compared to a control group as well as to the acute effects and a sham operated group. Activation of the muscle at increasing lengths after aponeurotomy caused a gap between the cut ends of the aponeurosis. However, after recovery, new connective tissue is formed bridging the aponeurotic ends, consisting of thin collagen fibres, which are densely packed and generally arranged in the direction of the aponeurosis. The number of fibroblasts was three to five times higher than that of aponeurotic tissue of the intact parts as well as that of the acute and sham operated muscles. The strain of the new connective tissue as a function of active muscle length was shown to be about three times higher than that of the aponeurosis. It is concluded that the inserted new aponeurotic tissue is more compliant and that the aponeurosis becomes 10-15% longer than in untreated muscle. As a consequence, the muscle fibres located distally to the new aponeurotic tissue will become shorter than prior to aponeurotomy. This explains a shift of the length-force curve, which favours the restoration of the range of joint motion.

Protection of dogs for 13 months against Bordetella bronchiseptica and canine parainfluenza virus with a modified live vaccine.

Twelve specific pathogen-free (spf) puppies were vaccinated intranasally with a bivalent, modified live vaccine against infectious tracheobronchitis (group 1) and six puppies of the same age and from the same source served as unvaccinated controls (group 2). Both groups were challenged with wild-type Bordetella bronchiseptica and canine parainfluenza virus by the aerosol route 56 weeks after group 1 had been vaccinated, and at the same time six 10-week-old spf puppies from the same source (group 3) were also challenged. Oronasal swabs were taken regularly before and after the challenge, for the isolation of bacteria and viruses, and the dogs were observed for clinical signs for three weeks after the challenge. The control dogs became culture-positive for B bronchiseptica and canine parainfluenza virus, but the isolation yields from the vaccinated group were significantly lower (P<0.05). The mean clinical scores of the vaccinated group were 61 per cent lower than the scores of group 2 (P=0.009), and 90 per cent lower than the scores of group 3 (P=0.001).

Haloperidol and cognitive shifting.

In this study haloperidol appeared to affect the performance on a selected category of cognitive tasks considered to represent shifting aptitude. A pretest--post-test design was used with two groups of subjects: 17 patients suffering from idiopathic spasmodic torticollis, and 17 controls who were matched for age and intelligence. The results are discussed in relation to previous findings on haloperidol and cognition, shifting disorder in Parkinson's disease and changes in behavioural organization found in animals with an experimentally induced dopaminergic hypoactivity.

Anatomically distinct output channels of the caudate nucleus and orofacial dyskinesia: critical role of the subcommissural part of the globus pallidus in oral dyskinesia.

The findings in this feline study indicate that the enkephalin-positive subcommissural part of the globus pallidus, which is known to contain GABA and cholinergic cells projecting to the cortex, is innervated by the anterodorsal region of the caudate nucleus, but not by the core. Like stimulation of a particular subclass of dopamine receptors in the anterodorsal region of the caudate nucleus, inhibition of the GABA receptors in the noted part of the globus pallidus resulted in orofacial dyskinesia, viz. tic-like contractions of the facial, eye and ear muscles, and tongue protrusions. This phenomenon was elicited by intrapallidal injections of the GABA antagonist picrotoxin in a dose-dependent manner and could be attenuated by the GABA agonist muscimol. Previous studies have already shown that neither stimulation of the dopamine receptors in the core of the caudate nucleus nor any manipulation with the first- and second-order output-stations of the latter brain region, viz. (a) those regions of the substantia nigra, pars reticulata which receive afferents from the caudate nucleus, and (b) those regions of the intermediate layers of the superior colliculus which receive afferents from the latter nigral region, ever resulted in orofacial dyskinesia. These findings support the hypothesis that the anatomically distinct input-output channels of the caudate nucleus are differentially involved in orofacial dyskinesia. The clinical impact of these findings is discussed in view of the L-3,4-dihydroxyphenylalanine-induced tardive dyskinesia in man. In addition, the relevance of the anatomical data is discussed in view of the co-occurrence of Parkinson's Disease and Dementia of Alzheimer-type in certain patients.

Progressive pathology of the caudate nucleus, the substantia nigra pars reticulata and the deeper layers of the colliculus superior: acute behavioural and metabolic effects of intrastriatal kainic acid.

The acute behavioural and metabolic consequences of functional changes following unilateral intracaudate kainic acid at the level of the feline caudate nucleus, the substantia nigra pars reticulata and the deeper layers of the colliculus superior were investigated. The present study became possible since it was previously found that unilateral changes in neurotransmission processes in these structures all result in behavioural alterations that can be distinguished from each other. During the first 17 min after kainic acid, all animals displayed contralateral forced staccato head turning; these movements are characteristic for an activation of dopamine receptors and/or inhibition of GABA receptors in the rostromedial caudate nucleus. Between 15 and 50 min, all animals displayed fast, uninterrupted contralateral forced head, torso or body turning; these movements are characteristic for an activation of nigral GABA receptors. From about 48 min, all animals displayed sequences of short contralateral forced ear, head, torso and body turnings; these movements are characteristic for an inhibition of collicular GABA receptors. Furthermore, most cats displayed ipsilateral orofacial dyskinetic movements during the whole 180 min observation period. Metabolism was analysed in three cats that received [14C]2-D-deoxyglucose immediately before, 5 min after, or 70 min after kainic acid. Metabolism was increased in the ipsilateral caudate nucleus; this effect was most pronounced in the cat that received deoxyglucose immediately before kainic acid. Metabolic activity was increased in the ipsilateral substantia nigra pars reticulata; this effect was most pronounced in the cat treated with deoxyglucose 5 min after kainic acid. Metabolism was increased in the ipsilateral deeper layers of the colliculus superior in the cat that received deoxyglucose 70 min after kainic acid. The present behavioural and metabolic data suggest that kainic acid produces an increasing pathology resulting successively in functional changes in the caudate nucleus, its output-station the substantia nigra pars reticulata and the nigral output-station the deeper layers of the colliculus superior. It is suggested that the successive appearance of the latter effects is inherent in the hierarchical order of the brain structures under study. The occurrence of orofacial dyskinetic movements during the whole observation period suggests that the former movements were not mediated via the striato-nigro-collicular pathway. Finally, apomorphine injected in the ipsilateral caudate nucleus 1 week after kainic acid was significantly less effective compared to apomorphine injected 1 week before kainic acid. The c

Scale size of magnetic turbulence in tokamaks probed with 30-MeV electrons

Measurements of synchrotron radiation emitted by 30-MeV runaway electrons in the TEXTOR-94 tokamak show that the runaway population decays after switching on neutral beam injection (NBI). The decay starts only with a significant delay, which decreases with increasing NBI heating power. This delay provides direct evidence of the energy dependence of runaway confinement, which is expected if magnetic modes govern the loss of runaways. Application of the theory by Mynick and Strachan [Phys. Fluids 24, 695 (1981)] yields estimates for the "mode width" (delta) of magnetic perturbations: delta<0.5 cm in Ohmic discharges, increasing to delta = 4.4 cm for 0. 6 MW NBI.

Quasistationary high confinement discharges with trans-greenwald density on TEXTOR-94

Confinement quality as good as ELM-free H-mode at densities substantially above the Greenwald density limit ( &nmacr;(e,0)/n(GW) = 1.4) has been obtained in discharges with a radiative boundary under quasistationary conditions for 20 times the energy confinement time. This is achieved by optimizing the gas-fueling rate of RI-mode discharges which tailors their favorable energy confinement and leads to discharges with beta values just below the operational limit beta(n) = 2 of TEXTOR-94, thereby effectively avoiding confinement back transitions or disruptions. In addition, this high-density regime is favorable for helium removal and results in figures of merit tau(*)(p,He)/tau(E) approximately 10-15, relevant for a future fusion power reactor.

Behavioural correlates of a progressive dysfunctioning of the caudate nucleus: effects of apomorphine.

During the ontogeny of many mammalian species there exists a remarkable resemblance with respect to the strict order in the appearance of distinct motor patterns during development. Moreover, along a cephalocaudal gradient more and more body parts become involved in these motor patterns. The same sequence in motor behaviour can be observed when adult animals start to explore a novel environment. On the other hand, s.c. injections of apomorphine result in a reversed 'ontogenetic' sequence of motor patterns: a 'breakdown' of motor behaviour. The present study investigated whether striatal injections of apomorphine produced a reversed 'breakdown' of a motor pattern sequence. Therefore, cats were tested in a paradigm in which they executed sequences of distinct motor patterns in order to collect food pellets when walking on the belt of a treadmill. As only one of the motor patterns in the sequence is caudate-specific, disturbances at the level of the caudate nucleus as well as disturbances at the level of other brain structures can be distinguished. In contrast to 0.6 and 2.5 micrograms, doses of 5.0 and 10.0 micrograms of apomorphine resulted in the successive breakdown of motor pattern sequences, whereby not only caudate-specific motor patterns were reduced, but also non-caudate-specific motor patterns. Moreover, this regression appeared in the reversed order compared to the order in which distinct patterns are executed during eating behaviour. The regression in motor behaviour following 5.0 micrograms apomorphine was induced via caudate dopamine receptors since it could be prevented by pretreatment with haloperidol. Because of the fact that 5.0 and 10.0 micrograms of apomorphine also affected motor patterns which are not caudate- and dopamine-specific, it is concluded that also brain structures receiving (in)directly caudate output signals are involved in the regression of the motor pattern sequence as observed in the present study. The clinical relevance of the presented data is discussed.