Effect of metabolic enzymes on acceleration ability in exercise fatigue / Efeito das enzimas metabólicas na capacidade de aceleração na fadiga por exercício / Efecto de las enzimas metabólicas sobre la capacidad de aceleración en la fatiga por ejercicio

ABSTRACT Introduction Study the relationship between the metabolic enzyme and the biological image, filtered by an adaptive filtering algorithm. Objective The research aims to In this study, human metabolic enzymes were evaluated by electrocardiogram and electromyogram images, and an adaptive filtering algorithm removed the noises in the images. Methods The electrocardiogram and electromyogram images at different periods were obtained, and the calculation method and application scope of the adaptive filtering algorithm were analysed. Results Adaptive filter was designed by the combination of adaptive filtering algorithm and dynamic information. Therefore, the artefact of the image was removed. Conclusions The adaptive filtering algorithm can effectively remove the noise or artefact in electrocardiogram and electromyogram signals. The optimal image information can be obtained. Level of evidence II; Therapeutic studies - investigation of treatment results.

RESUMO Introdução Estudar a relação entre a enzima metabólica e a imagem biológica filtrada por um algoritmo de filtragem adaptativa. Objetivo O objetivo da pesquisa, neste estudo, é avaliar enzimas metabólicas humanas por meio de imagens de eletrocardiograma e eletromiograma, sendo que um algoritmo de filtragem adaptativa eliminou o ruído nas imagens. Métodos Imagens de eletrocardiograma e eletromiograma foram obtidas em diferentes períodos e foram analisados o método de cálculo e o escopo de aplicação do algoritmo de filtragem adaptativa. Resultados a filtragem adaptativa foi projetada combinando um algoritmo de filtragem adaptativa e informações dinâmicas. Portanto, o artefato foi removido da imagem. Conclusões O algoritmo de filtragem adaptativa pode efetivamente eliminar ruído ou artefato em sinais de eletrocardiograma e eletromiograma. Informações de imagem ideais podem ser obtidas. Nível de evidência II; Estudos terapêuticos: investigação dos resultados do tratamento.

RESUMEN Introducción Estudiar la relación entre la enzima metabólica y la imagen biológica, filtrada por un algoritmo de filtrado adaptativo. Objetivo La investigación tiene como objetivo, en este estudio, evaluar las enzimas metabólicas humanas mediante imágenes de electrocardiograma y electromiograma, y un algoritmo de filtrado adaptativo eliminó los ruidos en las imágenes. Métodos Se obtuvieron las imágenes de electrocardiograma y electromiograma en diferentes períodos y se analizó el método de cálculo y alcance de aplicación del algoritmo de filtrado adaptativo. Resultados El filtrado adaptativo se diseñó mediante la combinación de un algoritmo de filtrado adaptativo e información dinámica. Por lo tanto, se eliminó el artefacto de la imagen. Conclusiones El algoritmo de filtrado adaptativo puede eliminar eficazmente el ruido o artefacto en las señales de electrocardiograma y electromiograma. Se puede obtener la información de imagen óptima. Nivel de evidencia II; Estudios terapéuticos: investigación de los resultados del tratamiento.

SDH Subunit C Regulates Muscle Oxygen Consumption and Fatigability in an Animal Model of Pulmonary Emphysema.

Patients with pulmonary emphysema often develop locomotor muscle dysfunction, which is independently associated with disability and higher mortality in that population. Muscle dysfunction entails reduced force generation capacity, which partially depends on fibers' oxidative potential, yet very little mechanistic research has focused on muscle respiration in pulmonary emphysema. Using a recently established animal model of pulmonary emphysema-driven skeletal muscle dysfunction, we found downregulation of SDHC (succinate dehydrogenase subunit C) in association with lower oxygen consumption and fatigue tolerance in locomotor muscles. Reduced SDH activity has been previously observed in muscles from patients with pulmonary emphysema, and we found that SDHC is required to support respiration in cultured muscle cells. Moreover, in vivo gain of SDH function in emphysema animals' muscles resulted in better oxygen consumption rate and fatigue tolerance. These changes correlated with a larger number of relatively more oxidative type 2-A and 2X fibers and a reduced amount of 2B fibers. Our data suggest that SDHC is a key regulator of respiration and fatigability in pulmonary emphysema-driven skeletal muscles, which could be impactful in developing strategies aimed at attenuating this comorbidity.

Targeting sirtuin activity with nicotinamide riboside reduces neuroinflammation in a GWI mouse model.

Gulf War Illness (GWI) affects 30% of veterans from the 1991 Gulf War (GW), who suffer from symptoms that reflect ongoing mitochondria dysfunction. Brain mitochondria bioenergetics dysfunction in GWI animal models corresponds with astroglia activation and neuroinflammation. In a pilot study of GW veterans (n = 43), we observed that blood nicotinamide adenine dinucleotide (NAD) and sirtuin 1 (Sirt1) protein levels were decreased in the blood of veterans with GWI compared to healthy GW veterans. Since nicotinamide riboside (NR)-mediated targeting of Sirt1 is shown to improve mitochondria function, we tested whether NR can restore brain bioenergetics and reduce neuroinflammation in a GWI mouse model. We administered a mouse diet supplemented with NR at 100µg/kg daily for 2-months to GWI and control mice (n = 27). During treatment, mice were assessed for fatigue-type behavior using the Forced Swim Test (FST), followed by euthanasia for biochemistry and immunohistochemistry analyses. Fatigue-type behavior was elevated in GWI mice compared to control mice and lower in GWI mice treated with NR compared to untreated GWI mice. Levels of plasma NAD and brain Sirt1 were low in untreated GWI mice, while GWI mice treated with NR had higher levels, similar to those of control mice. Deacetylation of the nuclear-factor κB (NFκB) p65 subunit and peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α) was an increase in the brains of NR-treated GWI mice. This corresponded with a decrease in pro-inflammatory cytokines and lipid peroxidation and an increase in markers of mitochondrial bioenergetics in the brains of GWI mice. These findings suggest that targeting NR mediated Sirt1 activation restores brain bioenergetics and reduces inflammation in GWI mice. Further evaluation of NR in GWI is warranted to determine its potential efficacy in treating GWI.

Cancer-related fatigue and biochemical parameters among cancer patients with different stages of sarcopenia.

PURPOSE: Cancer-related fatigue (CRF) is a pervasive symptom experienced by cancer patients. Sarcopenia has been suggested as a treatment target of CRF. This study aims to assess the differences of CRF and biochemical markers among different stages of sarcopenia which remain poorly delineated. METHODS: A total of 187 patients were included in this cross-sectional study. Based on muscle mass (skeletal muscle index, SMI), muscle strength (handgrip strength), and physical performance (SARC-F score), patients were divided into four groups (non-sarcopenia, pre-sarcopenia, sarcopenia, and severe sarcopenia). Cancer-related fatigue was measured by the Brief Fatigue Inventory (BFI). Biochemical markers were measured by routine blood tests. RESULTS: The BFI score was significantly associated with sarcopenia stage (r=0.500; P<0.001). Cancer patients in severe sarcopenia group suffered from worse CRF than those in non-sarcopenia, pre-sarcopenia, and sarcopenia groups (P<0.001). In the multivariate linear regression model (R2=0.542), CRF was significantly correlated with SARC-F score (standardized B=0.519; P<0.001) and high-sensitivity C-reactive protein (standardized B=0.389; P=0.004). Serum albumin and cholinesterase were statistically correlated with both sarcopenia stage and CRF. CONCLUSIONS: The significantly increased occurrence and severity of CRF in cancer patients with sarcopenia suggest that sarcopenia may be a crucial target to improve the management of CRF. Circulating albumin and cholinesterase have the potential to predicting sarcopenia as biomarkers.

Post-Stroke Fatigue May Be Associated with the Promoter Region of a Monoamine Oxidase A Gene Polymorphism.

BACKGROUND: Post-stroke fatigue (PSF) is a common sequela of stroke. Despite reports of serotonergic involvement in the etiology of PSF, the potential contribution of serotonergic genes in the development of PSF needs to be investigated. METHODS: A total of 373 patients, who experienced ischemic stroke for PSF, were evaluated 3 months after the stroke. PSF was assessed using the Fatigue Severity Scale. The genomic DNA collected and stored in a -70°C freezer was genotyped for 6 polymorphisms in genes associated with serotonin synthesis (tryptophan hydroxylase 1 (TPH1) A218C, TPH2 rs10879355, and TPH2 rs4641528), transport (the promoter region of the serotonin transporter protein), and catabolism (the 30-bp functional variable number tandem repeat) polymorphism in the promoter region of monoamine oxidase A (MAO-A). RESULTS: Among the 373 patients, 164 (44%) had PSF. All patients were ethnic Koreans. Of the 6 polymorphisms examined, only one marker, that is, low-activity MAO-A was associated with PSF (p < 0.05) in female patients. Multiple logistic regression analyses showed that post-stroke depression (PSD; 95% CI 1.561-14.323, p = 0.006) and low MAO-A activity (95% CI 0.166-0.722, p = 0.005) were factors associated with PSF in female patients, whereas only PSD (95% CI 5.511-65.269, p = 0.000) was associated with PSF in male patients. CONCLUSIONS: Our findings suggest that PSF may be associated with a genetic polymorphism involving MAO-A, at least in female stroke patients.

Investigations on the antifatigue and antihypoxic effects of Paecilomyces hepiali extract.

Paecilomyces hepiali, one of the most valuable and effective Chinese medicinal herbs, possesses potential antioxidant, immunomodulatory, antitumor and anti­inflammatory properties. The present study aimed to investigate the antifatigue and antihypoxic effects of Paecilomyces hepiali extract (PHC) in a mouse model. Using a rotating rod, forced swimming and running assessment, the antifatigue activity of PHC was determined. PHC administration for 7 days had no effect on mouse horizontal or vertical movement, indicating no neurotoxicity at the selected doses was observed. Using a normobaric hypoxia, sodium nitrite toxicosis and acute cerebral ischemia assessments, PHC was confirmed to possess antihypoxic effects. PHC treatment for 7 days significantly enhanced the serum and liver levels of adenosine triphosphate, superoxide dismutase and glutathione peroxidase, prior to and following 60 min of swimming. The levels of antioxidant­associated proteins in the livers of the mice were analyzed using western blotting. PHC effectively increased the expression levels of phosphorylated (p)­5'­monophosphate (AMP)­activated protein kinase (AMPK), p­protein kinase B (AKT) and p­mammalian target of rapamycin (mTOR). The results of the present study demonstrated that PHC efficiently enhanced endurance from fatigue and had antihypoxic effects through elevation of the antioxidant capacity in the serum and liver, at least in part through the AMPK and AKT/mTOR pathways. These results indicate the potential of this natural product as an antioxidant in the treatment of fatigue, hypoxia and their associated diseases.

Inflammation-induced activation of the indoleamine 2,3-dioxygenase pathway: Relevance to cancer-related fatigue.

Cancer-related fatigue (CRF) is a common complication of cancer and its treatment that can significantly impair quality of life. Although the specific mechanisms remain poorly understood, inflammation is now considered to be a distinct component of CRF in addition to effects of depression, anxiety, insomnia, and other factors. One key biological pathway that may link inflammation and CRF is indoleamine 2,3-dioxygenase (IDO). Induced by inflammatory stimuli, IDO catabolizes tryptophan to kynurenine (KYN), which is subsequently converted into neuroactive metabolites. Here we summarize current knowledge concerning the relevance of the IDO pathway to CRF, including activation of the IDO pathway in cancer patients and, as a consequence, accumulation of neurotoxic KYN metabolites and depletion of serotonin in the brain. Because IDO inhibitors are already being evaluated as therapeutic agents in cancer, the elucidation of the relationship between IDO activation and CRF in cancer patients may lead to novel diagnostic and clinical approaches to managing CRF and its debilitating consequences.

Investigation of MTHFR C677T gene polymorphism, biochemical and clinical parameters in Turkish migraine patients: association with allodynia and fatigue.

We investigated whether there is any relationship between biochemical and clinical parameters of migraine and methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism, associated with the migraine subtypes, symptoms, and gender. A total of 150 migraine patients with and without aura (MA and MO) and 107 non-sufferers were included in the study. Biochemical and clinical parameters were measured and genetic analysis was performed. The MTFHR C677T genotype was significantly higher in the migraine group (p = 0.000). The CT genotype frequency of individuals with a family history of migraine was significantly higher (p = 0.025). This genotype frequency was higher in patients who suffer from compression, allodynia, fatigue, and sleeplessness (p = 0.027, 0.023, 0.006, and 0.05, respectively). Homocysteine and total cholesterol levels were significantly higher in the migraine group than the control group (p = 0.007 and 0.010, respectively). However, the other biochemical and clinical parameters did not differ from each other (p > 0.05), with only attack frequency being significantly higher in the MO group (p = 0.005). While the folate and HDL levels were significantly higher in females (p = 0.001 and 0.000, respectively), the homocysteine and triglyceride levels were significantly higher in males (p = 0.000 for each one). BMIs were significantly lower in the control than the migraine group (p = 0.021); however, an association between the C677T variant and BMI was not found (p = 0.787) in the migraine group. An association between the MTHFR C667T polymorphism and migraine susceptibility was found. Additional studies including genetic, clinic, and biochemical parameters should be conducted to better understand the disease.

Effect of seabuckthorn (Hippophae rhamnoides ssp. sinensis) leaf extract on the swimming endurance and exhaustive exercise-induced oxidative stress of rats.

BACKGROUND: Seabuckthorn (SBT) leaves have significant antioxidant, immunomodulatory and anti-inflammatory properties. The objective of this study was to assess the anti-fatigue, antioxidant and tissue-protective properties of aqueous lyophilised extracts of SBT dried leaves in the hearts of Wistar male rats undergoing exhaustive physical exercise. Doses of 50, 200 and 800 mg kg⁻¹ body weight (BW) day⁻¹ were given orally for 1 week. A week later the rats were forced to swim in barrels until they were exhausted. The times were noted to establish the effective dose of the extracts in rats. After establishing the effective dose, the rats were then sacrificed and assessed for various biochemical parameters. RESULTS: SBT leaf aqueous extracts (200 and 800 mg kg⁻¹ BW) markedly prolonged the swim time of rats. Supplementation with SBT leaf aqueous extracts helped reduce the exhaustive exercise-induced increase in malondialdehyde level and selenium-dependent glutathione peroxidase activity. Alanine aminotransferase and creatine kinase levels were lowered in the exhaustive exercise with SBT treatment group (E + SBT) compared with the exhaustive exercise group (E). CONCLUSION: The findings suggest that SBT leaf aqueous extract supplements can enhance exercise capacity and protect against oxidative damage caused by exhaustive exercise in rats.

Effects of grape seed extract supplementation on exercise-induced oxidative stress in rats.

The aim of the present study was to investigate the effects of grape seed extract (GSE) supplementation on exercise performance and oxidative stress in acutely and chronically exercised rats. A total of sixty-four male rats were used in the study. Rats were divided into six groups: control, chronic exercise control, acute exercise control (AEC), GSE-supplemented control, GSE-supplemented chronic exercise and GSE-supplemented acute exercise groups. Chronic exercise consisted of treadmill running at 25 m/min, 45 min/d, 5 d a week for 6 weeks. Rats in the acute exercise groups were run on the treadmill at 30 m/min until exhaustion. GSE were given at 100 mg/kg of body weight with drinking water for 6 weeks. Plasma was separated from blood samples for the analysis of oxidative stress markers. There was no significant difference in time of exhaustion between the acute exercise groups. Plasma malondialdehyde (MDA) levels were higher in the acute exercise groups and lower in the chronic exercise groups. GSE supplementation decreased MDA levels. Xanthine oxidase and adenosine deaminase activities were higher in the AEC group compared to all the other groups. NO levels were increased with both chronic exercise and GSE supplementation. Superoxide dismutase and glutathione peroxidase activities were lower in the acute exercised groups and higher in the chronic exercised groups. GSE supplementation caused an increase in antioxidant enzyme activities. In conclusion, GSE supplementation prevents exercise-induced oxidative stress by preventing lipid peroxidation and increasing antioxidant enzyme activities.

Early activation of p38 mitogen activated protein kinase is associated with interferon-alpha-induced depression and fatigue.

Cytokine-induced stimulation of p38 mitogen activated protein kinase (MAPK) has been shown to influence behaviorally-relevant pathophysiologic pathways including monoamine neurotransmission and neuroendocrine function and thus may contribute to behavioral changes that occur during chronic administration of the innate immune cytokine, interferon (IFN)-alpha. Accordingly, in the current study, phosphorylation (activation) of intracellular p38 MAPK in peripheral blood lymphocytes was analyzed by flow cytometry every 2 h for 12 h following the initial injection of IFN-alpha in eleven patients with chronic hepatitis C. Hourly assessments of plasma concentrations of adrenocorticotropic hormone, cortisol and interleukin-6 were also obtained. Symptoms of depression and fatigue were measured at baseline and after 4 and 12 weeks of IFN-alpha treatment. Acute administration of IFN-alpha significantly increased the percentage of lymphocytes staining positive for intracellular phosphorylated p38 (p-p38). IFN-alpha-induced increases in p-p38 were significantly greater in patients that developed clinically significant depressive symptoms [Montgomery-Asberg Depression Rating Scale (MADRS) score≥15] during the first 12 weeks of IFN-alpha treatment. Increases in the percentage of p-p38-positive lymphocytes following the first IFN-alpha injection also highly correlated with depression severity at weeks 4 (r=0.85, p=0.001) and 12 (r=0.70, p=0.018). Similar relationships were observed for fatigue. Examination of relationships between p-p38 induction and factors previously reported to predict IFN-alpha-induced depressive symptoms revealed strong associations of p-p38 with baseline MADRS (r=0.82, p=0.002) and cortisol responses to the initial injection of IFN-alpha (r=0.91, p=0.000). Taken together, these findings indicate that sensitivity of p38 MAPK signaling pathways to immune stimulation is associated with depressive symptoms during chronic IFN-alpha treatment.

More aroused, less fatigued: fatty acid amide hydrolase gene polymorphisms influence acute response to amphetamine.

Amphetamine is a stimulant drug that enhances attention and feelings of alertness. Amphetamine's effects are known to be modulated by endogenous cannabinoids, which are degraded by the enzyme fatty acid amide hydrolase (FAAH). In this study we investigated inter-individual differences in mood response to amphetamine in relation to four polymorphisms in the FAAH gene, including the FAAH missense variant rs324420C --> A (Pro129Thr), which was previously found to be associated with street drug use and addictive traits. One hundred and fifty-nine healthy Caucasian volunteers participated in a three-session, double-blind crossover study receiving either placebo or oral d-amphetamine (10 and 20 mg). Associations between individual genotypes and levels of self-reported Arousal (Profile of Mood States) after d-amphetamine ingestion were investigated using two-way ANOVAs/ANCOVAs. Association analyses for haplotypes were performed using the adaptive permutation approach implemented in PLINK. Genotypes at rs3766246 and rs2295633 were significantly associated with increased ratings of Arousal (p<0.05) and Fatigue (p<0.01) after the 10-mg dose. Fatigue levels were also found to be associated with the haplotypes CCC and TAT formed from rs3766246, rs324420, and rs2295633 (p<0.05). These data suggest that the endocannabinoid system influences variation in subjective response to amphetamine. This has important implications for understanding the role of endogenous cannabinoids in response to amphetamine, studies of poly-substance abuse, and understanding the genetic determinants of inter-individual differences in stimulant effects and risk of abuse.

Chronic fatigue stress leads to up-regulation of nitric oxide synthase in the rat nucleus accumbens.

In the present study, the effect of chronic fatigue stress on the neuronal nitric oxide synthase (nNOS) in the rat nucleus accumbens (NAc) was assessed in order to explore the neurobiology mechanism of central fatigue stress, especially the role of the NAc in central fatigue. In the experiment, adult male Wistar rats were forced to swim till exhaustion every day for 4 weeks. Immunohistochemistry was used for measurement of the nNOS-positive neurons associated with the image manipulation. Our results showed that a long-time exposure to chronic forced swim stress increased the number of nNOS immunoreactive-positive neurons in the rat NAc (106.7%, P<0.001), distributed area (150.2%, P<0.001) and gray degree value (11.3%, P<0.01). The results indicate that nitric oxide (NO)/nNOS may be involved in the formation of the fatigue stress, and that NO may play a role in the regulation of stress in the NAc. The up-regulation of NO/nNOS during the exposure to long-time swim stress is likely to be one of the results of brain damage and psychiatric disorder induced by NO overproduction.

Decrease of hepatic delta-aminolevulinate dehydratase activity in an animal model of fatigue.

Fatigue can be defined physiologically as inability to maintain the expected power output. At present, no standard of fatigue are yet available. In order to find biomarkers of fatigue, we investigated the level of delta-aminolevulinic acid (ALA), the first intermediate metabolite in the heme biosynthetic pathway, in the plasma and urine of an animal model of fatigue. To prepare fatigued animals, we kept rats for 5 days in a cage filled with water to a height of 1.5 cm. As a result, the plasma and urinary ALA levels were increased in the fatigued animals as compared with those in the control animals. One day after the rats had been returned to their normal cages, these increased levels were restored to the control ones. We also examined the activity of the enzyme ALA dehydratase (ALAD), which is the second enzyme in the heme biosynthetic pathway, and ALAD gene expression during the fatigue and its recovery sessions. The ALAD activity, as well as its gene expression, in the liver of the fatigued animals was decreased as compared with those of the control animals. Both activity and gene expression of ALAD were recovered to their respective control levels after the rats had been allowed to rest in their normal cages for 1 day. Furthermore, the activity of ALA synthase (ALAS), the rate-limiting enzyme in the heme biosynthesis, in the liver was increased after the fatigue session for 5 days. Although this level of increase in the plasma concentration of ALA may not induce fatigue, increase in plasma and urinary ALA levels can be biomarkers of fatigue.

Depressed Na+-K+-ATPase activity in skeletal muscle at fatigue is correlated with increased Na+-K+-ATPase mRNA expression following intense exercise.

We investigated whether depressed muscle Na(+)-K(+)-ATPase activity with exercise reflected a loss of Na(+)-K(+)-ATPase units, the time course of its recovery postexercise, and whether this depressed activity was related to increased Na(+)-K(+)-ATPase isoform gene expression. Fifteen subjects performed fatiguing, knee extensor exercise at approximately 40% maximal work output per contraction. A vastus lateralis muscle biopsy was taken at rest, fatigue, 3 h, and 24 h postexercise and analyzed for maximal Na(+)-K(+)-ATPase activity via 3-O-methylfluorescein phosphatase (3-O-MFPase) activity, Na(+)-K(+)-ATPase content via [(3)H]ouabain binding sites, and Na(+)-K(+)-ATPase alpha(1)-, alpha(2)-, alpha(3)-, beta(1)-, beta(2)- and beta(3)-isoform mRNA expression by real-time RT-PCR. Exercise [352 (SD 267) s] did not affect [(3)H]ouabain binding sites but decreased 3-O-MFPase activity by 10.7 (SD 8)% (P < 0.05), which had recovered by 3 h postexercise, without further change at 24 h. Exercise elevated alpha(1)-isoform mRNA by 1.5-fold at fatigue (P < 0.05). This increase was inversely correlated with the percent change in 3-O-MFPase activity from rest to fatigue (%Delta3-O-MFPase(rest-fatigue)) (r = -0.60, P < 0.05). The average postexercise (fatigue, 3 h, 24 h) alpha(1)-isoform mRNA was increased 1.4-fold (P < 0.05) and approached a significant inverse correlation with %Delta3-O-MFPase(rest-fatigue) (r = -0.56, P = 0.08). Exercise elevated alpha(2)-isoform mRNA at fatigue 2.5-fold (P < 0.05), which was inversely correlated with %Delta3-O-MFPase(rest-fatigue) (r = -0.60, P = 0.05). The average postexercise alpha(2)-isoform mRNA was increased 2.2-fold (P < 0.05) and was inversely correlated with the %Delta3-O-MFPase(rest-fatigue) (r = -0.68, P < 0.05). Nonsignificant correlations were found between %Delta3-O-MFPase(rest-fatigue) and other isoforms. Thus acute exercise transiently decreased Na(+)-K(+)-ATPase activity, which was correlated with increased Na(+)-K(+)-ATPase gene expression. This suggests a possible signal-transduction role for depressed muscle Na(+)-K(+)-ATPase activity with exercise.

Exceptionally elevated creatine kinase levels in a laryngectomized patient: hypothyroid myopathy.

We present a laryngectomized patient with unspecific complaints of fatigue whose laboratory findings were out of proportion with the clinical presentation. The enormously high blood levels of creatine kinase (CPK) (8000 IU/l, normal range 30-190 IU/l) and thyroid-stimulating hormone (100 mU/l, normal range 0.5-4.5 mU/l) led to diagnosis and treatment of and recovery from hypothyroid myopathy. Hypothyroidism reduces the ability of the muscle to maintain its adequate energetic economy, via several suggested mechanisms. This may lead to injury (myopathy) that allows enzymes such as CPK to leak out of cells and causes elevation of their serum levels. To our knowledge, this is the first reported case of a patient previously treated for head and neck cancer who developed hypothyroid myopathy, presenting with exceptionally elevated CPK levels. This is noteworthy, since hypothyroidism may be easily avoided by a comprehensive follow-up of patients treated for head and neck cancer.

Cloning of dimethylglycine dehydrogenase and a new human inborn error of metabolism, dimethylglycine dehydrogenase deficiency.

Dimethylglycine dehydrogenase (DMGDH) (E.C. number 1.5.99.2) is a mitochondrial matrix enzyme involved in the metabolism of choline, converting dimethylglycine to sarcosine. Sarcosine is then transformed to glycine by sarcosine dehydrogenase (E.C. number 1.5.99.1). Both enzymes use flavin adenine dinucleotide and folate in their reaction mechanisms. We have identified a 38-year-old man who has a lifelong condition of fishlike body odor and chronic muscle fatigue, accompanied by elevated levels of the muscle form of creatine kinase in serum. Biochemical analysis of the patient's serum and urine, using (1)H-nuclear magnetic resonance NMR spectroscopy, revealed that his levels of dimethylglycine were much higher than control values. The cDNA and the genomic DNA for human DMGDH (hDMGDH) were then cloned, and a homozygous A-->G substitution (326 A-->G) was identified in both the cDNA and genomic DNA of the patient. This mutation changes a His to an Arg (H109R). Expression analysis of the mutant cDNA indicates that this mutation inactivates the enzyme. We therefore confirm that the patient described here represents the first reported case of a new inborn error of metabolism, DMGDH deficiency.

Association of genetically proven deficiencies of myophosphorylase and AMP deaminase: a second case of 'double trouble'.

We studied a 25-year-old man with paresis of the limbs and neck, scapular atrophy, facial weakness, exercise intolerance and frequent episodes of myoglobinuria. Muscle histochemistry and biochemistry revealed a combined defect of myophosphorylase and AMP deaminase. Molecular genetic analysis showed that the patient was homozygous for the two most common mutations associated with myophosphorylase and AMP deaminase deficiencies. This is the second documented case of genetic 'double trouble', which should be looked for in patients with unusual severe phenotypes.