The Experts below are selected from a list of 252 Experts worldwide ranked by ideXlab platform
Akihiko Ishihara - One of the best experts on this subject based on the ideXlab platform.
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A threshold dose of heavy ion radiation that decreases the Oxidative Enzyme activity of spinal motoneurons in rats.
Neurochemical research, 2011Co-Authors: Akihiko Ishihara, Fumiko Nagatomo, Hidemi Fujino, Hiroyo Kondo, Kumie NojimaAbstract:The effect of heavy ion radiation exposure of the spinal cord on the properties of the motoneurons innervating the slow soleus and fast plantaris muscles was investigated. A 15-, 20-, 40-, 50-, or 70-Gy dose of carbon ions (5 Gy/min) was applied to the 2nd to the 6th lumbar segments of the spinal cord in rats. After a 1-month recovery period, the number and cell body size of the irradiated motoneurons innervating the soleus and plantaris muscles did not differ from that of the non-irradiated controls, irrespective of the dose received. However, the Oxidative Enzyme activity of these motoneurons was decreased by heavy ion radiation at doses of 40, 50, and 70 Gy compared to that of the non-irradiated controls. This decrease in Oxidative Enzyme activity levels in the motoneurons returned to that of the non-irradiated controls after a 6-month recovery period. We conclude that heavy ion radiation at doses of 40–70 Gy reversibly decreases the Oxidative Enzyme activity of motoneurons in the spinal cord of rats.
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Cell Size and Oxidative Enzyme Activity of Rat Biceps Brachii and Triceps Brachii Muscles
The journal of physiological sciences : JPS, 2007Co-Authors: Akiko Matsumoto, Fumiko Nagatomo, Ayako Mori, Yoshinobu Ohira, Akihiko IshiharaAbstract:Fiber-type distributions, cross-sectional areas, and Oxidative Enzyme activities of type-identified fibers in the biceps brachii and triceps brachii muscles of 10-week-old male Wistar rats were determined and compared with those in the soleus and plantaris muscles. The soleus and plantaris muscles consisted of two (I and IIA) and three (I, IIA, and IIB) types of fibers, respectively. The deep regions of the biceps brachii and triceps brachii muscles consisted of three types of fibers, while the surface regions of those muscles consisted only of type IIB fibers. The cross-sectional areas of fibers in the deep and surface regions of the plantaris muscle and in the deep regions of the biceps brachii and triceps brachii muscles were in the rank order of type I = type IIA < type IIB, while the Oxidative Enzyme activities of fibers in the deep and surface regions of the plantaris muscle and in the deep region of the triceps brachii muscle were in the rank order of type IIB < type I = type IIA. These results indicate that fiber-type distributions, cross-sectional areas, and Oxidative Enzyme activities are muscle type- and region-specific. Therefore, the metabolic and functional significance of the biceps brachii and triceps brachii muscles, especially in the surface regions, where only type IIB fibers are located, in those muscles, appears to be determined by their fibers having larger cells and lower Oxidative Enzyme activity.
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Responses of Neuromuscular Systems under Gravity or Microgravity Environment
Uchū Seibutsu Kagaku, 2004Co-Authors: Akihiko Ishihara, Fuminori Kawano, Xiao Dong Wang, Yoshinobu OhiraAbstract:Hindlimb suspension of rats induces induces fiber atrophy and type shift of muscle fibers. In contrast, there is no change in the cell size or Oxidative Enzyme activity of spinal motoneurons innervating muscle fibers. Growth-related increases in the cell size of muscle fibers and their spinal motoneurons are inhibited by hindlimb suspension. Exposure to microgravity induces atrophy of fibers (especially slow-twitch fibers) and shift of fibers from slow- to fast-twitch type in skeletal muscles (especially slow, anti-gravity muscles). In addition, a decrease in the Oxidative Enzyme activity of spinal motoneurons innervating slow-twitch fibers and of sensory neurons in the dorsal root ganglion is observed following exposure to microgravity. It is concluded that neuromuscular activities are important for maintaining metabolism and function of neuromuscular systems at an early postnatal development and that gravity effects both efferent and afferent neural pathways.
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Cell Size and Oxidative Enzyme Activity of Type-Identified Fibers in Rat Hindlimb Muscles: a Review
ACTA HISTOCHEMICA ET CYTOCHEMICA, 2003Co-Authors: Toshiaki Nakatani, Toshikatsu Nakashima, Taizo Kita, Akihiko IshiharaAbstract:Mammalian skeletal muscles are comprised of heterogeneous types of fibers based on their Enzyme histochemical or immunohistochemical properties. Regardless of the muscle type, muscle region, or fiber type, an inverse relationship between cross-sectional area and Oxidative Enzyme activity of fibers is observed in the rat hindlimb muscles including the soleus, plantaris, extensor digitorum longus, and tibialis anterior muscles. This indicates that smaller-sized fibers have higher Oxidative Enzyme activities than larger-sized fibers even within the same fiber type. In addition, there is a matching of cell sizes and Oxidative Enzyme activities of spinal motoneurons and the muscle fibers that they innervate, which is important for maintaining their functional and metabolic properties.
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Effects of hypophysectomy on soleus muscle fibers and spinal motoneurons in rats.
Acta Neuropathologica, 1995Co-Authors: Akihiko Ishihara, Kazuo Itoh, Minoru Itoh, Chiyoko Hirofuji, Hitomi HayashiAbstract:The fiber type distribution of the soleus muscle in male and female rats was investigated 4 weeks after hypophysectomy. Oxidative Enzyme activity of the soleus motoneurons in the spinal cord was also examined by Enzyme histochemical assay. In male rats, the total number of fibers in the soleus muscle was not changed after hypophysectomy, but the percentage of intermediate (INT) fibers (with intermediate adenosine triphosphatase activity following alkaline preincubation, and high succinate dehydrogenase and α-glycerophosphate dehydrogenase activities) was increased. All types of fibers in the soleus muscle of hypophysectomized rats showed high adenosine triphosphatase activity following acid preincubation. Oxidative Enzyme activity of the motoneurons innervating the soleus muscle was not changed after hypophysectomy. Similar results were obtained in female rats. It is suggested that the increased percentage of INT fibers in the rat soleus muscle after hypophysectomy is due to a lack or reduced levels of growth hormones, and that the metabolic capacities of the muscle fibers and of the innervating motoneurons are affected independently by hypophysectomy.
Alan Pestronk - One of the best experts on this subject based on the ideXlab platform.
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Sarcopenia, age, atrophy, and myopathy: Mitochondrial Oxidative Enzyme activities.
Muscle & nerve, 2017Co-Authors: Alan Pestronk, Richard M. Keeling, Rati ChoksiAbstract:Objective: We studied mitochondrial impairment as a factor in the pathologic equivalent of sarcopenia, muscle fiber atrophy associated with increased age. Methods: Mitochondrial Oxidative Enzyme activities and coEnzyme Q10 levels were measured in frozen human proximal limb muscles with combined age and atrophy, age alone, atrophy alone, denervation, immune myopathies, and mitochondrial disorders with ophthalmoplegia. Results: Sarcopenia (age and atrophy) had reduced mean activities of mitochondrial Complexes I, II, and II+III, with severe reduction of Complex I activity in 54% of patients. Atrophy, and specific denervation atrophy, had similar patterns of changes. Age alone had moderately reduced Complex I activity. Mitochondrial myopathies had mildly lower Complex IV activity. Immune myopathies had unchanged Enzyme activities. Interpretation: Mitochondrial Oxidative Enzyme activities, especially Complex I, but also Complexes II and II+III, are reduced in muscles with the pathologic equivalent of sarcopenia. Individually, atrophy and age have different patterns of Oxidative Enzyme changes. This article is protected by copyright. All rights reserved.
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coEnzyme q10 deficiency in children frequent type 2c muscle fibers with normal morphology
Muscle & Nerve, 2013Co-Authors: Brian R Sommerville, Craig M. Zaidman, Alan PestronkAbstract:Introduction: Neurological disorders with low tissue coEnzyme Q10 (CoQ10) levels are important to identify, as they may be treatable. Methods: We evaluated retrospectively clinical, laboratory, and muscle histochemistry and Oxidative Enzyme characteristics in 49 children with suspected mitochondrial disorders. We compared 18 with CoQ10 deficiency in muscle to 31 with normal CoQ10 values. Results: Muscle from CoQ10-deficient patients averaged 5.5-fold more frequent type 2C muscle fibers than controls (P < 0.0001). A type 2C fiber frequency of ≥ 5% had 89% sensitivity and 84% specificity for CoQ10 deficiency in this cohort. No biopsy showed active myopathy. There were no differences between groups in frequencies of mitochondrial myopathologic, clinical, or laboratory features. Multiple abnormalities in muscle Oxidative Enzyme activities were more frequent in CoQ10-deficient patients than in controls. Conclusions: When a childhood mitochondrial disorder is suspected, an increased frequency of type 2C fibers in morphologically normal muscle suggests CoQ10 deficiency. Muscle Nerve 48:722–726, 2013
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CoEnzyme Q10 deficiency in children: frequent type 2C muscle fibers with normal morphology.
Muscle & nerve, 2013Co-Authors: R. Brian Sommerville, Craig M. Zaidman, Alan PestronkAbstract:Introduction: Neurological disorders with low tissue coEnzyme Q10 (CoQ10) levels are important to identify, as they may be treatable. Methods: We evaluated retrospectively clinical, laboratory, and muscle histochemistry and Oxidative Enzyme characteristics in 49 children with suspected mitochondrial disorders. We compared 18 with CoQ10 deficiency in muscle to 31 with normal CoQ10 values. Results: Muscle from CoQ10-deficient patients averaged 5.5-fold more frequent type 2C muscle fibers than controls (P
Jean Jobin - One of the best experts on this subject based on the ideXlab platform.
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Oxidative Enzyme activities of the vastus lateralis muscle and the functional status in patients with copd
Thorax, 2000Co-Authors: Francois Maltais, Pierre Leblanc, Francois Whittom, C Simard, Karine Marquis, Marthe Belanger, Mariejosee Breton, Jean JobinAbstract:BACKGROUND Enzymatic and histochemical abnormalities of the peripheral muscle may play a role in exercise intolerance in patients with chronic obstructive pulmonary disease (COPD). A study was undertaken to measure the mitochondrial Enzyme activity of the vastus lateralis muscle in patients with COPD and to evaluate the relationship between Enzyme activities and functional status. METHODS Fifty seven patients with COPD of mean (SD) age 66 (7) years with forced expiratory volume in one second (FEV1) 39 (15)% predicted and peak oxygen uptake (V˙o 2) of 14 (4) ml/min/kg and 15 normal subjects of similar age were included in the study. Each subject performed a stepwise exercise test up to maximal capacity during which five-breath averages of V˙o 2were measured. Muscle specimens were obtained by percutaneous needle biopsy of the vastus lateralis muscle and the activity of two mitochondrial Enzymes (citrate synthase (CS) and 3-hydroxyacyl CoA dehydrogenase (HADH)) was measured. The functional status of the patients was classified according to peakV˙o 2. RESULTS CS and HADH activities were markedly reduced in patients with COPD compared with normal subjects (22.3 (2.7) versus 29.5 (7.3) μmol/min/g muscle (p<0.0001) and 5.1 (2.0) versus 6.7 (1.9) μmol/min/g muscle (p<0.005), respectively). The activity of CS decreased progressively with the deterioration in the functional status while that of HADH was not related to functional status. Using a stepwise regression analysis, percentage predicted functional residual capacity (FRC), the activity of CS, oxygen desaturation during exercise, age, and inspiratory capacity (% pred) were found to be significant determinants of peakV˙o 2. The regression model explained 59% of the variance in peak V˙o 2 (p<0.0001). CONCLUSIONS The Oxidative capacity of the vastus lateralis muscle is reduced in patients with moderate to severe COPD compared with normal subjects of similar age. In these individuals the activity of CS correlated significantly with peak exercise capacity and independently of lung function impairment.
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Oxidative Enzyme activities of the vastus lateralis muscle and the functional status in patients with copd
Thorax, 2000Co-Authors: Francois Maltais, Pierre Leblanc, Francois Whittom, C Simard, Karine Marquis, Marthe Belanger, Mariejosee Breton, Jean JobinAbstract:BACKGROUND Enzymatic and histochemical abnormalities of the peripheral muscle may play a role in exercise intolerance in patients with chronic obstructive pulmonary disease (COPD). A study was undertaken to measure the mitochondrial Enzyme activity of the vastus lateralis muscle in patients with COPD and to evaluate the relationship between Enzyme activities and functional status. METHODS Fifty seven patients with COPD of mean (SD) age 66 (7) years with forced expiratory volume in one second (FEV1) 39 (15)% predicted and peak oxygen uptake (V˙o 2) of 14 (4) ml/min/kg and 15 normal subjects of similar age were included in the study. Each subject performed a stepwise exercise test up to maximal capacity during which five-breath averages of V˙o 2were measured. Muscle specimens were obtained by percutaneous needle biopsy of the vastus lateralis muscle and the activity of two mitochondrial Enzymes (citrate synthase (CS) and 3-hydroxyacyl CoA dehydrogenase (HADH)) was measured. The functional status of the patients was classified according to peakV˙o 2. RESULTS CS and HADH activities were markedly reduced in patients with COPD compared with normal subjects (22.3 (2.7) versus 29.5 (7.3) μmol/min/g muscle (p<0.0001) and 5.1 (2.0) versus 6.7 (1.9) μmol/min/g muscle (p<0.005), respectively). The activity of CS decreased progressively with the deterioration in the functional status while that of HADH was not related to functional status. Using a stepwise regression analysis, percentage predicted functional residual capacity (FRC), the activity of CS, oxygen desaturation during exercise, age, and inspiratory capacity (% pred) were found to be significant determinants of peakV˙o 2. The regression model explained 59% of the variance in peak V˙o 2 (p<0.0001). CONCLUSIONS The Oxidative capacity of the vastus lateralis muscle is reduced in patients with moderate to severe COPD compared with normal subjects of similar age. In these individuals the activity of CS correlated significantly with peak exercise capacity and independently of lung function impairment.
David E Kelley - One of the best experts on this subject based on the ideXlab platform.
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skeletal muscle lipid content and Oxidative Enzyme activity in relation to muscle fiber type in type 2 diabetes and obesity
Diabetes, 2001Co-Authors: Jing He, Simon C Watkins, David E KelleyAbstract:In obesity and type 2 diabetes, skeletal muscle has been observed to have a reduced Oxidative Enzyme activity, increased glycolytic activity, and increased lipid content. These metabolic characteristics are related to insulin resistance of skeletal muscle and are factors potentially related to muscle fiber type. The current study was undertaken to examine the interactions of muscle fiber type in relation to Oxidative Enzyme activity, glycolytic Enzyme activity, and muscle lipid content in obese and type 2 diabetic subjects compared with lean healthy volunteers. The method of single-fiber analysis was used on vastus lateralis muscle obtained by percutaneous biopsy from 22 lean, 20 obese, and 20 type 2 diabetic subjects (ages 35 ± 1, 42 ± 2, and 52 ± 2 years, respectively), with values for BMI that were similar in obese and diabetic subjects (23.7 ± 0.7, 33.2 ± 0.8, and 31.8 ± 0.8 kg/m 2 , respectively). Oxidative Enzyme activity followed the order of type I > type IIa > type IIb, but within each fiber type, skeletal muscle from obese and type 2 diabetic subjects had lower Oxidative Enzyme activity than muscle from lean subjects ( P P
Francois Maltais - One of the best experts on this subject based on the ideXlab platform.
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Oxidative Enzyme activities of the vastus lateralis muscle and the functional status in patients with copd
Thorax, 2000Co-Authors: Francois Maltais, Pierre Leblanc, Francois Whittom, C Simard, Karine Marquis, Marthe Belanger, Mariejosee Breton, Jean JobinAbstract:BACKGROUND Enzymatic and histochemical abnormalities of the peripheral muscle may play a role in exercise intolerance in patients with chronic obstructive pulmonary disease (COPD). A study was undertaken to measure the mitochondrial Enzyme activity of the vastus lateralis muscle in patients with COPD and to evaluate the relationship between Enzyme activities and functional status. METHODS Fifty seven patients with COPD of mean (SD) age 66 (7) years with forced expiratory volume in one second (FEV1) 39 (15)% predicted and peak oxygen uptake (V˙o 2) of 14 (4) ml/min/kg and 15 normal subjects of similar age were included in the study. Each subject performed a stepwise exercise test up to maximal capacity during which five-breath averages of V˙o 2were measured. Muscle specimens were obtained by percutaneous needle biopsy of the vastus lateralis muscle and the activity of two mitochondrial Enzymes (citrate synthase (CS) and 3-hydroxyacyl CoA dehydrogenase (HADH)) was measured. The functional status of the patients was classified according to peakV˙o 2. RESULTS CS and HADH activities were markedly reduced in patients with COPD compared with normal subjects (22.3 (2.7) versus 29.5 (7.3) μmol/min/g muscle (p<0.0001) and 5.1 (2.0) versus 6.7 (1.9) μmol/min/g muscle (p<0.005), respectively). The activity of CS decreased progressively with the deterioration in the functional status while that of HADH was not related to functional status. Using a stepwise regression analysis, percentage predicted functional residual capacity (FRC), the activity of CS, oxygen desaturation during exercise, age, and inspiratory capacity (% pred) were found to be significant determinants of peakV˙o 2. The regression model explained 59% of the variance in peak V˙o 2 (p<0.0001). CONCLUSIONS The Oxidative capacity of the vastus lateralis muscle is reduced in patients with moderate to severe COPD compared with normal subjects of similar age. In these individuals the activity of CS correlated significantly with peak exercise capacity and independently of lung function impairment.
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Oxidative Enzyme activities of the vastus lateralis muscle and the functional status in patients with copd
Thorax, 2000Co-Authors: Francois Maltais, Pierre Leblanc, Francois Whittom, C Simard, Karine Marquis, Marthe Belanger, Mariejosee Breton, Jean JobinAbstract:BACKGROUND Enzymatic and histochemical abnormalities of the peripheral muscle may play a role in exercise intolerance in patients with chronic obstructive pulmonary disease (COPD). A study was undertaken to measure the mitochondrial Enzyme activity of the vastus lateralis muscle in patients with COPD and to evaluate the relationship between Enzyme activities and functional status. METHODS Fifty seven patients with COPD of mean (SD) age 66 (7) years with forced expiratory volume in one second (FEV1) 39 (15)% predicted and peak oxygen uptake (V˙o 2) of 14 (4) ml/min/kg and 15 normal subjects of similar age were included in the study. Each subject performed a stepwise exercise test up to maximal capacity during which five-breath averages of V˙o 2were measured. Muscle specimens were obtained by percutaneous needle biopsy of the vastus lateralis muscle and the activity of two mitochondrial Enzymes (citrate synthase (CS) and 3-hydroxyacyl CoA dehydrogenase (HADH)) was measured. The functional status of the patients was classified according to peakV˙o 2. RESULTS CS and HADH activities were markedly reduced in patients with COPD compared with normal subjects (22.3 (2.7) versus 29.5 (7.3) μmol/min/g muscle (p<0.0001) and 5.1 (2.0) versus 6.7 (1.9) μmol/min/g muscle (p<0.005), respectively). The activity of CS decreased progressively with the deterioration in the functional status while that of HADH was not related to functional status. Using a stepwise regression analysis, percentage predicted functional residual capacity (FRC), the activity of CS, oxygen desaturation during exercise, age, and inspiratory capacity (% pred) were found to be significant determinants of peakV˙o 2. The regression model explained 59% of the variance in peak V˙o 2 (p<0.0001). CONCLUSIONS The Oxidative capacity of the vastus lateralis muscle is reduced in patients with moderate to severe COPD compared with normal subjects of similar age. In these individuals the activity of CS correlated significantly with peak exercise capacity and independently of lung function impairment.
