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Fulltext Versatility of the latissimus dorsi flap in upper limb salvage tumour surgery

Dorai AA, Halim AS, Zulmi W

Med J Malaysia, 2004 Dec;59 Suppl F:42-6.
PMID: 15941160

Reconstructive surgeons often encounter complex soft tissue and skeletal defects following oncological surgery. Soft tissue defects after wide resection in upper extremities posses a difficult challenge to find adequate tissue for reconstructing these defects. Paucity of local tissues dictates the requirement of loco-regional or distant flaps for these complex soft tissue defects which often exposes tendons, bones, nerves and joints. The latissimus dorsi muscle is a near ideal flap for the reconstruction because of the long neurovascular pedicle, ease of mobilization and its expendability. It can be rotated, with or without overlying skin, to cover soft tissue defects of the shoulder arm and elbow. Due to the large size of the muscle, it can be used to resurface the soft tissue defects and cover all major structures. Eleven consecutive cases were reviewed in which latissimus dorsi myocutaneous flap was used to reconstruct soft tissue defects of the upper limb following radical tumor resection. Flap survival was 100% with nominal donor site morbidity.

Matched MeSH terms: Muscle, Skeletal/blood supply; Muscle, Skeletal/transplantation*
An assessment of heavy metal bioaccumulation in Asian swamp eel, Monopterus albus, during plowing stages of a paddy cycle

Sow AY, Ismail A, Zulkifli SZ

Bull Environ Contam Toxicol, 2013 Jul;91(1):6-12.
PMID: 23666324 DOI: 10.1007/s00128-013-1009-4

Livers and muscles of swamp eels (Monopterus albus) were analyzed for bioaccumulation of heavy metals during the plowing stage of a paddy cycle. Results showed heavy metals were bioaccumulated more highly in liver than muscle. Zinc (Zn) was the highest bioaccumulated metal in liver (98.5 ± 8.95 μg/g) and in muscle (48.8 ± 7.17 μg/g). The lowest bioaccumulated metals were cadmium (Cd) in liver (3.44 ± 2.42 μg/g) and copper (Cu) in muscle (0.65 ± 0.20 μg/g). In sediments, Zn was present at the highest mean concentration (52.7 ± 2.85 μg/g), while Cd had the lowest mean concentration (1.04 ± 0.24 μg/g). The biota-sediment accumulation factor (BSAF) for Cu, Zn, Cd and nickel (Ni) in liver tissue was greater than the corresponding BSAF for muscle tissue. For the three plowing stages, metal concentrations were significantly correlated between liver and muscle tissues in all cases, and between sediment and either liver or muscle in most cases. Mean measured metal concentrations in muscle tissue were below the maximum permissible limits established by Malaysian and U.S. governmental agencies, and were therefore regarded as safe for human consumption.

Matched MeSH terms: Muscle, Skeletal/drug effects; Muscle, Skeletal/metabolism
Micro-RNA and the Features of Metabolic Syndrome: A Narrative Review

Das S, Mohamed IN, Teoh SL, Thevaraj T, Ku Ahmad Nasir KN, Zawawi A, et al.

Mini Rev Med Chem, 2020;20(7):626-635.
PMID: 31969099 DOI: 10.2174/1389557520666200122124445

The incidence of Metabolic Syndrome (MetS) has risen globally. MetS includes a combination of features, i.e. blood glucose impairment, excess abdominal/body fat dyslipidemia and elevated blood pressure. Other than conventional treatment with drugs, the main preventive approaches include lifestyle changes, weight loss, diet control and adequate exercise also proves to be beneficial. MicroRNAs (miRNAs) are small non-coding RNAs that play critical regulatory roles in most biological and pathological processes. In the present review, we discuss various miRNAs which are related to MetS by targeting various organs, including the pancreas, liver, skeletal muscles and adipose tissues. These miRNAs have the effect on insulin production and secretion (miR-9, miR-124a, miR-130a,b, miR152, miR-335, miR-375), insulin resistance (miR-29), adipogenesis (miR-143, miR148a) and lipid metabolism (miR-192). We also discuss the miRNAs as potential biomarkers and future therapeutic targets. This review may be beneficial for molecular biologists and clinicians dealing with MetS.

Matched MeSH terms: Muscle, Skeletal
Fulltext Objective triceps muscle strength measurement using computerized adaptation

Amalourde A, Vinayaga P, Naveed N, Choon SK, Zaleha O

Med J Malaysia, 2004 Dec;59 Suppl F:8-13.
PMID: 15941154

In our centre the non-availability computerized exercise machines limits the objective monitoring of strength rehabilitation. We undertook this research programme to objectively measure triceps muscle strength by interfacing NORSK-Gym machine with accelerometer and positional transducers to a computer. This data was tabulated and processed using Microsoft Excel. The positional transducer was first calibrated and it showed an excellent Pearson Correlation Coefficients against a standard metric reading (r = 0.9999). Peak Force was used as a test parameter for isotonic triceps muscle strength measurements. The criterion-referenced validity was established as the peak forces measured using the accelerometer and positional transducer demonstrated identical Peak Forces (r = 0.94). Analysis of our mean Peak Force measurements using non-biological force as well as the intra-individual reproducibility demonstrated excellent Pearson Correlation Coefficients (r) = 0.982-0.998 and 0.929-0.972 respectively. This computerized adaptation of the NORSK-Gym machine produced an objective, valid and reproducible triceps muscle strength measurement.

Matched MeSH terms: Muscle, Skeletal/physiology*
Antiulcer activity of methanol-chloroform extract of Channa striatus fillet

Azemi AK, Abd Rahim MH, Mamat SS, Mat Jais AM, Zakaria ZA

Pak J Pharm Sci, 2018 Jan;31(1):143-151.
PMID: 29348096

Channa striatus (Haruan) is Malaysian freshwater fish that is traditionally used to treat ailments related to wound and also ulcers. The aimed of the present study was to determine the mechanisms of anti-ulcer activity of chloroform: methanol extract of C. striatus fillet (CMCS) in rats. The antiulcer profile of CMCS, given orally in the doses of 50, 250 and 500mg/kg, was assessed using the ethanol- and indomethacin-induced gastric ulcer models. The mechanisms of antiulcer of CMCS were determined as follows; i) the antisecretory activity of CMCS was measured using the pyloric ligation rat model, and; ii) the role of nitric oxide (NO) and sulfhydryl compounds in the modulation of CMCS antiulcer activity were determined by pre-treating the rats with L-NAME or NEM, respectively, followed by the pre-treatment of rats with CMCS before subjecting the animals to the ethanol-induced gastric ulcer model. From the results obtained, CMCS exerted significant (P<0.05) antiulcer activity in both models of gastric ulcer wherein the macroscopic and microscopic analysis of the stomach supported the antiulcer claim. With regard to its antisecretory effect, CMCS did not change the volume and pH, but reduce the total acidity only at the lower doses of the gastric juice. Moreover, CMCS demonstrated antiulcer activity was reversed by NEM, but not affected by L-NAME. In conclusion, CMCS shows antiulcer activity that is modulated via its cytoprotective, but not antisecretory effect, and in the presence of sulfhysryl compounds, but not NO.

Matched MeSH terms: Muscle, Skeletal/chemistry*
Scanning electron microscopy of the human muscular sarcocyst

Wong KT, Yusoff M

Parasitol Res, 1995;81(4):359-60.
PMID: 7624297
Matched MeSH terms: Muscle, Skeletal/parasitology*; Muscle, Skeletal/ultrastructure
Fulltext Hepatocellular carcinoma with disseminated skeletal muscle metastasis

Rahim EA, Noh MS, Ngah NA, Suraini MS, Yusof MM

Acta Radiol Open, 2017 Jul;6(7):2058460117716705.
PMID: 28811928 DOI: 10.1177/2058460117716705

Hepatocellular carcinoma (HCC) is the commonest primary tumor of the liver and carries a poor prognosis when diagnosed late or left untreated. Treatment relies heavily on the stage of the tumor when diagnosed. Extrahepatic metastasis is known to occur; these are mainly reported via autopsy studies or isolated case reports. Knowledge of extrahepatic metastasis is crucial in order to avoid unnecessary surgery. We report a rare case of a patient at our center, diagnosed to have HCC, who underwent treatment successfully, only to come back with extrahepatic metastasis to the skeletal muscles.

Matched MeSH terms: Muscle, Skeletal
Acute effect of static and dynamic stretching on hip dynamic range of motion during instep kicking in professional soccer players

Amiri-Khorasani M, Abu Osman NA, Yusof A

J Strength Cond Res, 2011 Jun;25(6):1647-52.
PMID: 21358428 DOI: 10.1519/JSC.0b013e3181db9f41

The purpose of this study was to examine the effects of static and dynamic stretching within a pre-exercise warm-up on hip dynamic range of motion (DROM) during instep kicking in professional soccer players. The kicking motions of dominant legs were captured from 18 professional adult male soccer players (height: 180.38 ± 7.34 cm; mass: 69.77 ± 9.73 kg; age: 19.22 ± 1.83 years) using 4 3-dimensional digital video cameras at 50 Hz. Hip DROM at backward, forward, and follow-through phases (instep kick phases) after different warm-up protocols consisting of static, dynamic, and no-stretching on 3 nonconsecutive test days were captured for analysis. During the backswing phase, there was no difference in DROM after the dynamic stretching compared with the static stretching relative to the no-stretching method. There was a significant difference in DROM after the dynamic stretching compared with the static stretching relative to the no-stretching method during (a) the forward phase with p < 0.03, (b) the follow-through phase with p < 0.01, and (c) all phases with p < 0.01. We concluded that professional soccer players can perform a higher DROM of the hip joint during the instep kick after dynamic stretching incorporated in warm-ups, hence increasing the chances of scoring and injury prevention during soccer games.

Matched MeSH terms: Muscle, Skeletal/physiology
Biomechanical responses of thigh and lower leg during 10 consecutive soccer instep kicks

Amiri-Khorasani M, Abu Osman NA, Yusof A

J Strength Cond Res, 2011 Apr;25(4):1177-81.
PMID: 20838249 DOI: 10.1519/JSC.0b013e3181d6508c

This study investigated the number of trials necessary to obtain optimal biomechanical responses in 10 consecutive soccer instep kicks. The kicking motions of dominant legs were captured from 5 experienced and skilled adult male soccer players (height: 184.60 ± 4.49 cm; mass: 80 ± 4.24 kg; and age: 25.60 ± 1.14 years) using a 3D infrared high-speed camera at 200 Hz. Some of the important kinematics and kinetics parameters are maximum thigh angular velocity, maximum lower leg angular velocity, maximum of thigh moment, maximum lower leg moment at forward and impact phases, and finally maximum ball velocity after impact selected to be analyzed. There was a significant decrease of ball velocity between the first and the fifth kick and the subsequent kicks. Similarly, the lower leg angular velocity showed a significant decrease after the fifth kick and thereafter. Compared with the first kick, the thigh angular velocity has been shown to decrease after the sixth kick and thereafter, and the thigh moment result of the sixth kick was significantly lower when compared with the first kick. Moreover, the lower leg moment result of the fourth kick was significantly lower in comparison with the first kick. In conclusion, it seems that 5 consecutive kicks are adequate to achieve high kinematics and kinetics responses and selecting more than 5 kicks does not result in any high biomechanical responses for analysis.

Matched MeSH terms: Muscle, Skeletal/physiology
Evaluation of Shoulder and Knee Isokinetic Strength Profile Among Elite Adolescent Badminton Players

Zulfikri N, Selvanayagam VS, Yusof A

J Sport Rehabil, 2021 Jan 19;30(5):717-724.
PMID: 33465761 DOI: 10.1123/jsr.2019-0483

CONTEXT: Badminton continues to be a highly competitive sport where training is introduced at an early age and load has intensiﬁed. This exposes players to a greater risk of injuries, in particular when assessing related training outcomes such as strength, agonist-antagonist ratio, and bilateral deﬁcit among adolescents where age- and sex-associated growth and development should be considered.
OBJECTIVE: To evaluate strength proﬁle of the upper and lower limbs among adolescent elite Malaysian badminton players.
DESIGN: Cross-sectional study.
SETTING: Laboratory.
PARTICIPANTS: Forty-eight asymptomatic athletes (24 males and 24 females) were grouped into early and late adolescence (13-14 y old and 15-17 y old, respectively).
MAIN OUTCOME MEASURE(S): Strength (absolute and normalized) of the external/internal rotators of the shoulder and ﬂexor/extensor of the knee and strength derivatives, conventional strength ratio (CSR), dynamic control ratio (DCR), and bilateral deﬁcits were measured.
RESULTS: Males showed greater strength in all strength indices (P < .05). The older group had greater strength compared to younger for most of the upper and lower limb indices (P < .05); these effects diminished when using normalized data. For females, there was no age group effect in the shoulder and knee strength. All players displayed lower shoulder and knee normative values for CSR and DCR. Dominant and non-dominant knee strength were comparable between sex and age groups.
CONCLUSIONS: For males, growth and maturation had a greater contribution to strength gained compared to training, whereas for females, growth, maturation, and training did not improve strength. The normalized data indicated that training did not improve all indices measured apart from external rotator strength in females. All players also displayed lower normative values of CSR and DCR. These results suggest that training in elite adolescent Malaysian badminton players lacks consideration of strength gain and injury risk factors.

Matched MeSH terms: Muscle, Skeletal/physiology
Role of carbohydrate in central fatigue: a systematic review

Khong TK, Selvanayagam VS, Sidhu SK, Yusof A

Scand J Med Sci Sports, 2017 Apr;27(4):376-384.
PMID: 27714855 DOI: 10.1111/sms.12754

Carbohydrate (CHO) depletion is linked to neuromuscular fatigue during exercise. While its role at peripheral level is relatively well understood, less is known about its impact centrally. The aim of this systematic review was to critically analyze the effects of CHO on central fatigue (CF) assessed by various neurophysiological techniques. Four databases were searched using PRISMA guidelines through February 2016. The inclusion criteria were: CHO as intervention against a placebo control, fatigue induced by prolonged exercise and assessed using neurophysiological measures [voluntary activation (VA), superimposed twitch (SIT), M-wave, electromyography], alongside maximal voluntary contraction (MVC). Seven papers were reviewed, where exercise duration lasted between 115 and 180 min. CHO improved exercise performance in three studies, whereby two of them attributed it to CF via attenuation of VA and SIT reductions, while the other indicated peripheral involvement via attenuation of M-wave reduction. Although a few studies suggest that CHO attenuates CF, data on its direct effects on neurophysiological outcome measures are limited and mixed. Generally, measures employed in these studies were inadequate to conclude central contribution to fatigue. Factors including the techniques used and the lack of controls render additional confounding factors to make definitive deductions. Future studies should employ consistent techniques and appropriate neurophysiological controls to distinguish CHO effect at central level. The use of pharmacological intervention should be incorporated to elucidate involvement of central mechanisms.

Matched MeSH terms: Muscle, Skeletal/metabolism*
Central effects of mouth rinses on endurance and strength performance

Tan SH, Khong TK, Selvanayagam VS, Yusof A

Eur J Appl Physiol, 2024 Feb;124(2):403-415.
PMID: 38038740 DOI: 10.1007/s00421-023-05350-w

Rinsing the mouth with a carbohydrate (CHO) solution has been shown to enhance exercise performance while reducing neuromuscular fatigue. This effect is thought to be mediated through the stimulation of oral receptors, which activate brain areas associated with reward, motivation, and motor control. Consequently, corticomotor responsiveness is increased, leading to sustained levels of neuromuscular activity prior to fatigue. In the context of endurance performance, the evidence regarding the central involvement of mouth rinse (MR) in performance improvement is not conclusive. Peripheral mechanisms should not be disregarded, particularly considering factors such as low exercise volume, the participant's fasting state, and the frequency of rinsing. These factors may influence central activations. On the other hand, for strength-related activities, changes in motor evoked potential (MEP) and electromyography (EMG) have been observed, indicating increased corticospinal responsiveness and neuromuscular drive during isometric and isokinetic contractions in both fresh and fatigued muscles. However, it is important to note that in many studies, MEP data were not normalised, making it difficult to exclude peripheral contributions. Voluntary activation (VA), another central measure, often exhibits a lack of changes, mainly due to its high variability, particularly in fatigued muscles. Based on the evidence, MR can attenuate neuromuscular fatigue and improve endurance and strength performance via similar underlying mechanisms. However, the evidence supporting central contribution is weak due to the lack of neurophysiological measures, inaccurate data treatment (normalisation), limited generalisation between exercise modes, methodological biases (ignoring peripheral contribution), and high measurement variability.Trial registration: PROSPERO ID: CRD42021261714.

Matched MeSH terms: Muscle, Skeletal/physiology
Fulltext Extracardiac Rhabdomyoma Mimicking Plunging Ranula

Hakim I, Yunus MRM

Medeni Med J, 2020;35(3):271-275.
PMID: 33110681 DOI: 10.5222/MMJ.2020.88120

Histopathologically adult extracardiac rhabdomyoma is a benign tumour of mature striated muscle. It is a slow- growing tumour with predilection to occur in head and neck region. They appear mainly as a solitary lesion, and about 15% of them can be multicentric. A 56-year-old man presented to us with the floor of mouth swelling persisted for one year and the right neck swelling for three years mimicking a plunging ranula. Radiological imaging revealed enhancing mass at the floor of mouth and submandibular region. The mass represented a nonvascular benign tumour. Subsequently, the patient underwent excision of the mass via transcervical and transoral method. Histopathological examination revealed adult type of extracardiac rhabdomyoma. Adult type of extracardiac rhabdomyoma should be considered in the differential diagnosis for the head and neck masses. A complete excision will reduce the risk of recurrence.

Matched MeSH terms: Muscle, Skeletal
Electrodiagnosis of reversible conduction failure in Guillain-Barré syndrome

Chan YC, Punzalan-Sotelo AM, Kannan TA, Shahrizaila N, Umapathi T, Goh EJH, et al.

Muscle Nerve, 2017 Nov;56(5):919-924.
PMID: 28093784 DOI: 10.1002/mus.25577

INTRODUCTION: In this study we propose electrodiagnostic criteria for early reversible conduction failure (ERCF) in axonal Guillain-Barré syndrome (GBS) and apply them to a cohort of GBS patients.
METHODS: Serial nerve conduction studies (NCS) were retrospectively analyzed in 82 GBS patients from 3 centers. The criteria for the presence of ERCF in a nerve were: (i) a 50% increase in amplitude of distal compound muscle action potentials or sensory nerve action potentials; or (ii) resolution of proximal motor conduction block with an accompanying decrease in distal latencies or compound muscle action potential duration or increase in conduction velocities.
RESULTS: Of 82 patients from 3 centers, 37 (45%) had ERCF, 21 (26%) had a contrasting evolution pattern, and 8 (10%) had both. Sixteen patients did not show an amplitude increase of at least 50%.
CONCLUSION: Our proposed criteria identified a group of patients with a characteristic evolution of NCS abnormality that is consistent with ERCF. Muscle Nerve 56: 919-924, 2017.

Matched MeSH terms: Muscle, Skeletal/physiopathology
Metabolic Effect of Dietary Taurine Supplementation on Nile Tilapia (Oreochromis nilotictus) Evaluated by NMR-Based Metabolomics

Shen G, Huang Y, Dong J, Wang X, Cheng KK, Feng J, et al.

J Agric Food Chem, 2018 Jan 10;66(1):368-377.
PMID: 29215281 DOI: 10.1021/acs.jafc.7b03182

Taurine is indispensable in aquatic diets that are based solely on plant protein, and it promotes growth of many fish species. However, the physiological and metabolome effects of taurine on fish have not been well described. In this study, 1H NMR-based metabolomics approaches were applied to investigate the metabolite variations in Nile tilapia (Oreochromis nilotictus) muscle in order to visualize the metabolic trajectory and reveal the possible mechanisms of metabolic effects of dietary taurine supplementation on tilapia growth. After extraction using aqueous and organic solvents, 19 taurine-induced metabolic changes were evaluated in our study. The metabolic changes were characterized by differences in carbohydrate, amino acid, lipid, and nucleotide contents. The results indicate that taurine supplementation could significantly regulate the physiological state of fish and promote growth and development. These results provide a basis for understanding the mechanism of dietary taurine supplementation in fish feeding. 1H NMR spectroscopy, coupled with multivariate pattern recognition technologies, is an efficient and useful tool to map the fish metabolome and identify metabolic responses to different dietary nutrients in aquaculture.

Matched MeSH terms: Muscle, Skeletal/metabolism; Muscle, Skeletal/chemistry
Fulltext Use of combined contralateral deltopectoral skin flap and ipsilateral island latissimus dorsi myocutaneous flap for massive cervico-thoracic oesophagus defect repair

Yap CM

Med J Malaysia, 2005 Aug;60(3):364-6.
PMID: 16379194

Restoring the intestinal continuity of an acquired massive cervico-thoracic oesophagus defect is a reconstructive challenge. A case requiring such defect restoration following a failed pedicled colonic interposition bypass graft between the cervical oesophagus and stomach for an intra-thoracic oesophageal perforation is presented. The defect between the oesophagostome at the lower left neck and the stoma of the colonic stump at the lower left chest measured about 20 cm. An ante-thoracic skin-tube neo-esophagus was constructed in two stages using a pedicled contralateral right deltopectoral skin flap and a pedicled ipsilateral island left latissimus dorsi myocutaneous flap (LD MC flap). A normal swallowing mechanism was re-established.

Matched MeSH terms: Muscle, Skeletal/surgery*
Fulltext Pathological findings in a mouse model for Coxsackievirus A16 infection

Hooi, Yuan Teng, Ong, Kien Chai, Perera, David, Wong, Kum Thong

Neurology Asia, 2015;20(4):343-347.
MyJurnal

Coxsackievirus A16 (CV-A16) is the leading cause of hand-foot-mouth disease (HFMD), which usually
presents as mild and self-limiting symptoms in young children. Rarely, CV-A16 has been reported
to cause severe and fatal neurological complications but little is known about these complications.
In the present study, 1-day and 7-day old mouse models of CV-A16 were developed using a clinical
strain via subcutaneous inoculation. All infected mice exhibited clinical signs of infection, including
reduced mobility, limb weakness and paralysis between 3 to 6 days post-infection. Pathologically,
the main organs involved were the central nervous system (CNS), skeletal muscles and brown fat. In
the CNS, viral antigens as demonstrated by immunohistochemistry, were localized mainly to neurons
in the brain stem and spinal cord, suggesting that CV-A16 is neurotropic although inflammation is
very mild. The skeletal muscles showed necrosis and myositis due to viral infection as evidenced by
the dense viral antigens. Focal viral antigens were also detected in the brown fat. These preliminary
pathological findings indicate that our mouse models can be further developed to be useful models
for pathogenesis studies, and vaccine and anti-viral drug evaluation.

Matched MeSH terms: Muscle, Skeletal
Fulltext Sarcocystis nesbitti infection in human skeletal muscle: possible transmission from snakes

Lau YL, Chang PY, Tan CT, Fong MY, Mahmud R, Wong KT

Am J Trop Med Hyg, 2014 Feb;90(2):361-4.
PMID: 24420776 DOI: 10.4269/ajtmh.12-0678

Sarcocystis nesbitti is an intracellular protozoan parasite found as sarcocysts within muscle fibers of intermediate hosts (monkey and baboon). The definitive host is suspected to be the snake. We report two cases from a larger cohort of 89 patients who had fever, headache, and generalized myalgia after a trip to Pangkor Island, Malaysia. Sarcocysts were detected in skeletal muscle biopsy specimens by light and electron microscopy from these two patients. DNA sequencing based on the 18S ribosomal DNA region identified the Sarcocystis species as S. nesbitti. We also identified S. nesbitti sequences in the stools of a snake (Naja naja). Phylogenetic analysis showed that these sequences form a cluster with most of the other known Sarcocystis species for which the snake is a definitive host. We believe these two patients were likely to have symptomatic acute muscular sarcocystosis after S. nesbitti infection that may have originated from snakes.

Matched MeSH terms: Muscle, Skeletal/parasitology*
Fulltext Pathologic characterization of a murine model of human enterovirus 71 encephalomyelitis

Ong KC, Badmanathan M, Devi S, Leong KL, Cardosa MJ, Wong KT

J. Neuropathol. Exp. Neurol., 2008 Jun;67(6):532-42.
PMID: 18520772 DOI: 10.1097/NEN.0b013e31817713e7

We describe a model of Enterovirus 71 encephalomyelitis in 2-week-old mice that shares many features with the human central nervous system (CNS) disease. Mice were infected via oral and parenteral routes with a murine-adapted virus strain originally from a fatal human case. The mice succumbed to infection after 2 to 5 days. Vacuolated and normal-appearing CNS neurons showed viral RNA and antigens and virions by in situ hybridization, immunohistochemistry, and electron microscopy; inflammation was minimal. The most numerous infected neurons were in anterior horns, motor trigeminal nuclei, and brainstem reticular formation; fewer neurons in the red nucleus, lateral cerebellar nucleus, other cranial nerve nuclei, motor cortex, hypothalamus, and thalamus were infected. Other CNS regions, dorsal root, and autonomic ganglia were spared. Intramuscular-inoculated mice killed 24 to 36 hours postinfection had viral RNA and antigens in ipsilateral lumbar anterior horn cells and adjacent axons. Upper cord motor neurons, brainstem, and contralateral motor cortex neurons were infected from 48-72 hours. Viral RNA and antigens were abundant in skeletal muscle and adjacent tissues but not in other organs. The distinct, stereotypic viral distribution in this model suggests that the virus enters the CNS via peripheral motor nerves after skeletal muscle infection, and spread within the CNS involves motor and other neural pathways. This model may be useful for further studies on pathogenesis and for testing therapies.

Matched MeSH terms: Muscle, Skeletal/virology
Perilipin 5 is dispensable for normal substrate metabolism and in the adaptation of skeletal muscle to exercise training

Mohktar RA, Montgomery MK, Murphy RM, Watt MJ

Am J Physiol Endocrinol Metab, 2016 07 01;311(1):E128-37.
PMID: 27189934 DOI: 10.1152/ajpendo.00084.2016

Cytoplasmic lipid droplets provide a reservoir for triglyceride storage and are a central hub for fatty acid trafficking in cells. The protein perilipin 5 (PLIN5) is highly expressed in oxidative tissues such as skeletal muscle and regulates lipid metabolism by coordinating the trafficking and the reversible interactions of effector proteins at the lipid droplet. PLIN5 may also regulate mitochondrial function, although this remains unsubstantiated. Hence, the aims of this study were to examine the role of PLIN5 in the regulation of skeletal muscle substrate metabolism during acute exercise and to determine whether PLIN5 is required for the metabolic adaptations and enhancement in exercise tolerance following endurance exercise training. Using muscle-specific Plin5 knockout mice (Plin5(MKO)), we show that PLIN5 is dispensable for normal substrate metabolism during exercise, as reflected by levels of blood metabolites and rates of glycogen and triglyceride depletion that were indistinguishable from control (lox/lox) mice. Plin5(MKO) mice exhibited a functional impairment in their response to endurance exercise training, as reflected by reduced maximal running capacity (20%) and reduced time to fatigue during prolonged submaximal exercise (15%). The reduction in exercise performance was not accompanied by alterations in carbohydrate and fatty acid metabolism during submaximal exercise. Similarly, mitochondrial capacity (mtDNA, respiratory complex proteins, citrate synthase activity) and mitochondrial function (oxygen consumption rate in muscle fiber bundles) were not different between lox/lox and Plin5(MKO) mice. Thus, PLIN5 is dispensable for normal substrate metabolism during exercise and is not required to promote mitochondrial biogenesis or enhance the cellular adaptations to endurance exercise training.

Matched MeSH terms: Muscle, Skeletal/metabolism*

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