Displaying publications 1 - 20 of 34 in total

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  1. Vijay, A.P., Tan, A.T.B., Suhaida, A.M., Chan, S.P.
    JUMMEC, 2010;13(1):63-68.
    MyJurnal
    Tumour-induced or oncogenic osteomalacia (OOM) is a rare paraneoplastic syndrome characterized by bone pain and muscle weakness. A biochemical profile consisting of normocalcaemia, hypophosphataemia, phosphaturia, increased serum alkaline phosphatase and inappropriately low serum levels of 1, 25-dihydroxyvitamin-D is diagnostic. OOM is usually caused by an osseous or soft-tissue tumour of mesenchymal origin that secretes phosphaturic substances leading to increased urinary phosphate wasting. These tumours are small and slow growing. The diagnosis continues to be easily missed and when eventually made, localization of the tumour can be difficult. We describe the case of a young man who presented with severe generalized pain associated with muscle weakness. He was extensively investigated and eventually diagnosed to have OOM 3 years after initial presentation. Specialized investigations were necessary to localize the offending tumour.
    Matched MeSH terms: Muscle Weakness
  2. Tan, C.L., Anne Yee, H.A., Majid, S.M., Koh, O.H., Ng, C.G.
    MyJurnal
    Steroid is commonly used for various connective tissue diseases and immunological related disorders. Psychiatric side effects are common in patient with systematic treatment of steroid. The reported prevalence ranges from 6% to 28%. Antidepressant-induced mania occurs when the mood of a patient switches to manic or hypomanic from depression after the use of antidepressant. We reported a case of a 55 year old lady, who presented with agitation and grandiosity after the treatment with antidepressant. She was initially diagnosed as having Bell’s palsy with unilateral facial muscle weakness. Oral prednisolone was prescribed for seven days where she became depressed, having auditory hallucination and delusion of guilt. She was then started on antidepressant where she became irritable, agitated and developed grandiose delusion. The antidepressant was withheld and she was started on atypical antipsychotic. Her condition improved and discharged well after three days of stay in the ward.
    Matched MeSH terms: Muscle Weakness
  3. Tan HT, Tan CY, Teong CS, Ratnasingam J, Goh KJ
    J Clin Neurophysiol, 2020 Aug 05.
    PMID: 32773648 DOI: 10.1097/WNP.0000000000000766
    PURPOSE: Thyrotoxic periodic paralysis is characterized by recurrent episodes of reversible, severe proximal muscle weakness associated with hypokalemia and hyperthyroidism. Prolonged exercise test is an easy, noninvasive method of demonstrating abnormal muscle membrane excitability in periodic paralyses. Although abnormal in thyrotoxic periodic paralysis patients, the effects thyroid hormone levels in non-thyrotoxic periodic paralysis thyrotoxicosis patients have not been well studied. The study aims to evaluate thyrotoxicosis patients (regardless of thyrotoxic periodic paralysis history) with prolonged exercise test and correlate it with their thyroid status.

    METHODS: This is a prospective, cross-sectional study of consecutive thyrotoxicosis patients seen at the endocrine clinic of a tertiary medical center. Thyroid status was determined biochemically before prolonged exercise test. Compound muscle action potential (CMAP) amplitudes postexercise were compared against pre-exercise amplitudes and recorded as percentage of mean baseline CMAP amplitude. Comparisons of time-dependent postexercise CMAP amplitudes and mean CMAP amplitude decrement were made between hyperthyroid and nonhyperthyroid groups.

    RESULTS: Seventy-four patients were recruited, 23 (31%) men, 30 (41%) Chinese, and the mean age was 48.5 ± 16.8 years. Of 74 patients, 32 (43%) were hyperthyroid and 42 (57%) were nonhyperthyroid viz. euthyroid and hypothyroid. Time-dependent CMAP amplitudes from 10 to 45 minutes after exercise were significantly lower in hyperthyroid patients compared with nonhyperthyroid patients (P < 0.01). Mean CMAP amplitude decrement postexercise was significantly greater in hyperthyroid than nonhyperthyroid patients (23.4% ± 11.4% vs. 17.3% ± 10.5%; P = 0.02).

    CONCLUSIONS: Compound muscle action potential amplitude declines on prolonged exercise test were significantly greater in hyperthyroid patients compared with nonhyperthyroid patients. Muscle membrane excitability is highly influenced by thyroid hormone level. Thyrotoxic periodic paralysis occurs from increased levels of thyroid hormone activity in susceptible patients.

    Matched MeSH terms: Muscle Weakness
  4. Singh DK, Bailey M, Lee R
    BMC Musculoskelet Disord, 2013 Jul 22;14:215.
    PMID: 23875830 DOI: 10.1186/1471-2474-14-215
    BACKGROUND: Muscle morphology, age and gender may be determinants of muscle strength in older adults. However, very few research studies have directly examined such correlation in the ageing spine. The aim of the study was to examine the correlation between lumbar extensor muscle strength, its muscle fibre angles, thoracolumbar curvature, age and gender in the older and younger adults.

    METHODS: Muscle fibre angles of lumbar extensor muscles, thoracolumbar curvature and lumbar extensor muscle strength were examined in 26 young (mean age 27.9, SD 5.2) and 26 older (mean age 72.1, SD 5.9) participants. Pearson's correlation was employed to determine the association among lumbar extensor muscle fibre angle, thoracolumbar curvature, age, gender and lumbar extensor muscle strength. Multiple stepwise linear regression analysis was used to identify significant determinants of lumbar extensor muscle strength.

    RESULTS: The results demonstrated a significant correlation between lumbar extensor muscle strength, muscle fibre angle, age and gender. In the step wise regression analysis, both gender and age were identified as the most robust determinant for lumbar extensor muscle strength in older adults. However, gender was the only determinant of muscle strength in the young.

    CONCLUSION: These results suggest that the decline in the lumbar extensor muscle strength in older adults was more dependent on age when compared to younger adults.

    Matched MeSH terms: Muscle Weakness/physiopathology*
  5. Seng, Wee Cheo, Rosdina Zamrud Ahmad Akbar, Tee, Tat Khoo, Kuo, Zhau Teo, Carwen Siaw, Qin, Jian Low
    MyJurnal
    Inflammatory myopathies (IM) is a rare inflammatory muscle disorder, which can be broadly divided into 5 subgroups. The accurate diagnosis of subtype of IM can be challenging due to a diverse presentation of the disease. On the other hand, skeletal muscle complication is common in patients with systemic lupus erythematosus (SLE) in the form of myalgia or myopathy. Inflammatory myopathy is a rare association of SLE and the diagnosis and treatment can be quite challenging. A 43-year-old lady with underlying systemic lupus erythematosus (SLE), presented with subacute onset progressively worsening muscle weakness involving upper limbs and lower limbs. Neurological examination showed findings consistent with proximal myopathy, with proximal power of 3/5 and distal power of 4/5. She has elevated creatinine kinase, ALT and AST level. Her myositis-specific autoantibodies were positive for anti-Ku antibodies. Her electromyography showed evidence of active myopathy of the upper and lower limb. Here, we would like to report a case of polymyositis in a patient with SLE.
    Matched MeSH terms: Muscle Weakness
  6. Roos A, van der Ven PFM, Alrohaif H, Kölbel H, Heil L, Della Marina A, et al.
    Brain, 2023 Oct 03;146(10):4200-4216.
    PMID: 37163662 DOI: 10.1093/brain/awad152
    Filamin-A-interacting protein 1 (FILIP1) is a structural protein that is involved in neuronal and muscle function and integrity and interacts with FLNa and FLNc. Pathogenic variants in filamin-encoding genes have been linked to neurological disorders (FLNA) and muscle diseases characterized by myofibrillar perturbations (FLNC), but human diseases associated with FILIP1 variants have not yet been described. Here, we report on five patients from four unrelated consanguineous families with homozygous FILIP1 variants (two nonsense and two missense). Functional studies indicated altered stability of the FILIP1 protein carrying the p.[Pro1133Leu] variant. Patients exhibit a broad spectrum of neurological symptoms including brain malformations, neurodevelopmental delay, muscle weakness and pathology and dysmorphic features. Electron and immunofluorescence microscopy on the muscle biopsy derived from the patient harbouring the homozygous p.[Pro1133Leu] missense variant revealed core-like zones of myofibrillar disintegration, autophagic vacuoles and accumulation of FLNc. Proteomic studies on the fibroblasts derived from the same patient showed dysregulation of a variety of proteins including FLNc and alpha-B-crystallin, a finding (confirmed by immunofluorescence) which is in line with the manifestation of symptoms associated with the syndromic phenotype of FILIP1opathy. The combined findings of this study show that the loss of functional FILIP1 leads to a recessive disorder characterized by neurological and muscular manifestations as well as dysmorphic features accompanied by perturbed proteostasis and myopathology.
    Matched MeSH terms: Muscle Weakness
  7. Rohana AG, Norasyikin AW, Suehazlyn Z, Ming W, Norlela S, Norazmi MK
    Med J Malaysia, 2006 Dec;61(5):638-40.
    PMID: 17623970 MyJurnal
    We report a case of a 65 year old Malay lady with long-standing diabetes mellitus, who presented to our institution with a one month history of worsening neck pain and progressive upper and lower limb weakness. She was stable despite severe hyponatraemia which was initially treated as syndrome of inappropriate anti-diuretic hormone (SIADH). This was consistent with her underlying illness which was concluded as cervical tuberculosis (TB) with spinal cord compression. She underwent decompression and bone grafting. Despite continuous treatment her serum sodium levels remained low. There were no other problems with her adrenals or thyroid. A water loading and hypertonic saline perfusion test was performed and supported the diagnosis of reset osmostat. Her serum sodium remained below the normal range and she was discharged well.
    Matched MeSH terms: Muscle Weakness
  8. Pike-See Cheah, Usman Bala, King-Hwa Ling
    MyJurnal
    Introduction: Down syndrome (DS) is caused by trisomy of human chromosome 21 (HSA21). Motor dysfunction due to hypotonia has limited labour productivity and have significant effects on socio-economic status in DS individuals. Ts1Cje, a mouse model of DS that exhibits muscle weakness was employed, to investigate the expression profile of selected trisomic and disomic genes involved in skeletal muscle structure and function. Methods: Quadriceps and triceps were harvested from the Ts1Cje (C57BL/6) postnatal day 60-70 mice and corresponding wild-type littermates. Total RNA extracted from these tissues was subjected for quantitative expression profiling of three trisomic genes (Itsn1, Synj1 and Rcan1) involved in neurotransmission and six disomic genes (Lamc1, Leprel1, Myl6b, Msn, Pgm5 and Tmod1) essential for maintenance of muscle structure and function. Real-time quantitative PCR method was used for the profiling. Results: Differential gene expression in DS is reflected by 1.5-fold or more increase in the level of expression as predicted by the gene dosage imbalance hypothesis. The analysis showed no significant changes in the expression level of trisomic genes (Itsn1, Synj1 and Rcan1). On contrary, disomic genes, Leprel1 and Pgm5, were upregulated for more than 1.5-fold in DS quadriceps whereas Lamc1, Myl6b and Pgm5 were upregulated for more than 1.5 fold in DS triceps as compared to the wild-type group. Conclusions: Our findings suggest that the dysregulation of Lamc1, Leprel1, Myl6b and Pgm5 genes is associated to muscle weakness seen in Ts1Cje and may play a role in molecular pathogenesis of muscle weakness in DS.
    Matched MeSH terms: Muscle Weakness
  9. Padmakumar V, Premkala Raveendran K, Abdulla AM, Ganapathy S, Sainudeen S, Nasim VS, et al.
    J Pharm Bioallied Sci, 2019 May;11(Suppl 2):S397-S401.
    PMID: 31198376 DOI: 10.4103/JPBS.JPBS_44_19
    Background: Mercury is a naturally occurring metal that exists in three forms: elemental (metallic), inorganic, and organic mercury. Amalgam, which is an alloy of inorganic mercury, is used as a restorative material in dentistry. Organic mercury gets ingested in the body mainly by the consumption of seafood. Mercury is also stated to cause various adverse health effects such as gastrointestinal disturbances, dermatitis, muscle weakness, and neurological disorders. In recent years, the use of amalgam has become a controversy stating the various adverse effects of mercury. Hence, the study was conducted to determine and compare the variation in levels of organic and inorganic mercury in fish-eating children before and after placement of amalgam restoration.

    Materials and Methods: Seventy-five subjects, 42 males (56%) and 35 females (44%) of age group ranging 7-13 years, living in South Canara district of Karnataka, India, were selected as a part of the study. Hair and urine samples were collected for estimation of organic and inorganic levels of mercury, respectively. Informed consent was collected from all the participating subjects.

    Results: On comparison between organic and inorganic mercury levels during the study period, the concentration of organic mercury in hair samples was greater irrespective of amalgam restorations present (1.172 and 0.085, respectively; P < 0.001).

    Conclusion: Thus inorganic levels of mercury do not seem to pose a threat as much as the organic levels observed in hair, which remain fairly constant for a longer period of time. Hence in a coastal region where this study was undertaken and fish being a staple food, the risk could probably be attributed to more of an organic toxicity than an inorganic one. Thus amalgam is relatively safe to be practiced and the controversy against it should be reevaluated.

    Matched MeSH terms: Muscle Weakness
  10. Ni H, Htet A
    PMID: 23074376 DOI: 10.3332/ecancer.2012.274
    Myasthenia gravis (MG) is an autoantibody-mediated disorder affecting the neuromuscular junction causing characteristic fatigable muscle weakness. Though it can be associated with tumours of the thymus as well as thyroid disorders, it is rare for both to coexist. The exact prevalence of thyroid carcinoma in MG with thymoma is not known but only about a dozen cases have been reported in the literature. We report a case of a 38-year-old Myanmar lady who presented with weakness and breathlessness due to MG with neck swelling. On examination, she had fatigable proximal muscle weakness and thyroid enlargement with no obvious features of hyperthyroidism. Mediastinal widening and an enlarged thyroid gland were noted on her chest X-ray and chest CT. A subtotal thyroidectomy and thymectomy were done. The histology showed follicular carcinoma of the thyroid and benign thymoma. The majority of the reported cases of thyroid carcinoma in association with MG were papillary carcinoma. Follicular carcinoma thyroid associated with MG has not yet been reported in the literature.
    Matched MeSH terms: Muscle Weakness
  11. Muthusamy KA, Waran V, Puthucheary SD
    J Clin Neurosci, 2007 Dec;14(12):1213-5.
    PMID: 17964168
    Burkholderia pseudomallei infection of the central nervous system (CNS) is rare with less than 50 cases reported over the last 30 years. The retrospective melioidosis study at University Malaya Medical Centre has documented three cases of CNS melioidosis out of more than 160 cases of melioidosis since 1978. There were two patients with brain abscess and one with spinal epidural abscess. The predisposing factors were: one patient was an aboriginal farmer and the other two were diabetic. Their age ranged from 17 to 45 years. Prominent neurological features were limb weakness, cranial nerve palsy (6th and 7th) and visual disturbance. CT brain scan and MRI spine showed abscess formation, subdural collection, and spinal epidural collection, osteomyelitis of vertebra and occipital bone and also sagital sinus thrombosis. All these patients underwent surgical drainage leading to bacteriological diagnosis as well as appropriate long-term antibiotic therapy. All had good recovery at 6 months after completion of treatment.
    Matched MeSH terms: Muscle Weakness/etiology
  12. Loi, H.D.K., Wong, K.T., Choo, K.E.
    MyJurnal
    An eight-year-old Chinese girl presented with a slowly progressive generalized muscle weakness and wasting, complicated by respiratory failure. She had many hospital admissions requiring ventilator support. Eventually tracheostomy tube was inserted. Initial investigations failed to elicit a diagnosis but a muscle biopsy and histological study confirmed the diagnosis of juvenile acid maltase deficiency.
    Matched MeSH terms: Muscle Weakness
  13. Lim, Chai Ling, Usman Bala, Leong, Melody Pui-Yee, Johnson Stanslas, Rajesh Ramasamy, Ling, King-Hwa, et al.
    MyJurnal
    Down syndrome (DS) is a genetic condition resulting from triplication of human chromosome (HSA)21. Besides intellectual disability, DS is frequently associated with hypotonia. Satellite cells are the resident cells that provides robust and remarkable regenerative capacity to the skeletal muscles, and its population size has been reported to be disease-associated. However, little is known about the population size of satellite cells in DS and the association of its intrinsic cellular functionality and hypotonia seen in DS. Here, we studied the Ts1Cje mouse, a DS murine model displays the muscle weakness characteristic. Satellite cell populations were immunostained with Pax7 and myonuclei numbers in the Ts1Cje extensor digitorum longus muscle were assessed. Their cellular function was further determined via in vitro assay in high-serum conditioned medium. Subsequently, the in vitro self-renewal, proliferative, and differentiation activities of these myogenic precursor cells were assessed after 24, 48, and 72h using Pax7, MyoD, and Ki67 immunomarkers. Our results showed that the population and functionality of Ts1Cje satellite cell did not differ significantly when compared to the wildtype cells isolated from disomic littermates. In conclusion, our findings indicated that intrinsic cellular functionality of the satellite cells, do not contribute to muscle weakness in Ts1Cje mouse.
    Matched MeSH terms: Muscle Weakness
  14. Lim JA, Lee ST, Moon J, Jun JS, Kim TJ, Shin YW, et al.
    Ann Neurol, 2019 03;85(3):352-358.
    PMID: 30675918 DOI: 10.1002/ana.25421
    OBJECTIVE: There is no scale for rating the severity of autoimmune encephalitis (AE). In this study, we aimed to develop a novel scale for rating severity in patients with diverse AE syndromes and to verify the reliability and validity of the developed scale.

    METHODS: The key items were generated by a panel of experts and selected according to content validity ratios. The developed scale was initially applied to 50 patients with AE (development cohort) to evaluate its acceptability, reproducibility, internal consistency, and construct validity. Then, the scale was applied to another independent cohort (validation cohort, n = 38).

    RESULTS: A new scale consisting of 9 items (seizure, memory dysfunction, psychiatric symptoms, consciousness, language problems, dyskinesia/dystonia, gait instability and ataxia, brainstem dysfunction, and weakness) was developed. Each item was assigned a value of up to 3 points. The total score could therefore range from 0 to 27. We named the scale the Clinical Assessment Scale in Autoimmune Encephalitis (CASE). The new scale showed excellent interobserver (intraclass correlation coefficient [ICC] = 0.97) and intraobserver (ICC = 0.96) reliability for total scores, was highly correlated with modified Rankin scale (r = 0.86, p

    Matched MeSH terms: Muscle Weakness/etiology; Muscle Weakness/physiopathology
  15. Lim CC, Lee WL, Leo YS, Lee KE, Chan KP, Ling AE, et al.
    J Neurol Neurosurg Psychiatry, 2003 Jan;74(1):131-3.
    PMID: 12486285
    The Nipah virus is a newly identified paramyxovirus responsible for an outbreak of fatal encephalitis in Malaysia and Singapore. This paper reports the follow up clinical and magnetic resonance imaging findings in 22 affected subjects. Of 13 patients with encephalitis, one died, one was lost to follow up, and seven recovered. Among the four remaining patients, one had residual sixth nerve palsy, another suffered from severe clinical depression, and a third patient had evidence of retinal artery occlusion. One patient with delayed onset Horner syndrome had a single lesion in the cervical spinal cord. The brain magnetic resonance findings were stable or improved in nine patients over 18 months of follow up. Among a second group of nine asymptomatic seropositive abattoir workers, magnetic resonance examination in seven subjects revealed discrete small lesions in the brain; similar to those detected in encephalitis patients. These findings suggest that in addition to encephalitis, the newly discovered Nipah virus affects the spinal cord and the retina. Late clinical and radiological findings can occur in Nipah virus infections as with other paramyxoviruses.
    Matched MeSH terms: Muscle Weakness/epidemiology
  16. Leong, Melody Pui Yee, Usman Bala, Lim, Chai Ling, Rozita Rosli, Cheah, Pike-See, Ling, King-Hwa
    Neuroscience Research Notes, 2018;1(1):21-41.
    MyJurnal
    Ts1Cje is a mouse model of Down syndrome (DS) with partial triplication of chromosome 16, which encompasses a high number of human chromosome 21 (HSA21) orthologous genes. The mouse model exhibits muscle weakness resembling hypotonia in DS individuals. The effect of extra gene dosages on muscle weakness or hypotonia in Ts1Cje and DS individuals remains unknown. To identify molecular dysregulation of the skeletal muscle, we compared the transcriptomic signatures of soleus and extensor digitorum longus (EDL) muscles between the adult Ts1Cje and disomic littermates. A total of 166 and 262 differentially expressed protein-coding genes (DEGs) were identified in the soleus and EDL muscles, respectively. The partial trisomy of MMU16 in Ts1Cje mice has a greater effect on gene expression in EDL. Top-down clustering analysis of all DEGs for represented functional ontologies revealed 5 functional clusters in soleus associated with signal transduction, development of reproductive system, nucleic acid biosynthesis, protein modification and metabolism as well as regulation of gene expression. On the other hand, only 3 functional clusters were observed for EDL namely neuron and cell development, protein modification and metabolic processes as well as ion transport. A total of 11 selected DEGs were validated using qPCR (disomic DEGs: Mansc1; trisomic DEGs: Itsn1, Rcan1, Synj1, Donson, Dyrk1a, Ifnar1, Ifnar2, Runx1, Sod1 and Tmem50b). The validated DEGs were implicated in neuromuscular junction signalling (Itsn1, Syn1), oxidative stress (Sod1, Runx1) and chronic inflammation processes (Runx1, Rcan1, Ifnar1, Ifnar2). Other validated DEGs have not been well-documented as involved in the skeletal muscle development or function, thus serve as interesting novel candidates for future investigations. To our knowledge, the study was the first attempt to determine the transcriptomic profiles of both soleus and EDL muscles in Ts1Cje mice. It provides new insights on the possible disrupted molecular pathways associated with hypotonia in DS individuals.
    Matched MeSH terms: Muscle Weakness
  17. Kwa, Siew Kim, Zainab Abdul Majeed, Tan, Kah Nian
    MyJurnal
    Myasthenia gravis (MG) is a rare autoimmune disorder
    characterised by fluctuating and variable combination
    of muscle weakness and fatigue. Most cases are due to
    T-cell mediated autoantibodies against post-synaptic
    acetylcholine receptors (AChR-Ab), thus preventing
    acetylcholine from binding and signalling skeletal
    muscle to contract.1
    The annual incidence is 7-23 new cases per million.1
    It can occur at any age but with two peaks; an earlyonset
    (20-40 years) female-predominant and a late-onset
    (60-80 years) male-predominant peak. MG is classified
    into ocular and generalised (80%). More than half the
    patients initially present with ptosis and diplopia but half
    will progress to generalised disease with involvement of
    bulbar, limb and respiratory weakness. Those presenting
    as generalised MG can also develop eye signs later.1
    It is important to recognise MG early because it is
    highly treatable. Untreated disease leads to permanent
    weakness.2 Treatment reduces mortality from lifethreatening
    myasthenic crisis.1,3 Misdiagnosis leads to
    potentially harmful interventions and inappropriate
    management.4,5 Diagnosis in late-onset MG is easily
    missed2,3,4,5 because of overlapping symptoms with
    other diseases common in the elderly. We report a case
    of delay and misdiagnosis in an elderly patient with
    co-morbidities. (Copied from article).
    Matched MeSH terms: Muscle Weakness
  18. Khoo HY, Tan WJ, Cheong YT
    Med J Malaysia, 2018 Feb;73(1):44-45.
    PMID: 29531202 MyJurnal
    Patients with breast cancer normally present with breast lump or abnormal mammogram. Dermatomyositis is rarely the first presentation. We present a case of a 63-year-old woman who had generalised dermatitis, progressive fatigue and muscle weakness. She was first diagnosed as dermatomyositis and subsequently breast cancer. Her rash and muscle weakness progressed drastically over a month. Tumescent mastectomy and axillary surgery was performed, which led to gradual regression of her dermatomyositis over six months. This case report emphasized in the benefit of early diagnosis and treatment of dermatomyositis and breast cancer. Pros and cons of tumescent mastectomy is discussed as well.
    Matched MeSH terms: Muscle Weakness
  19. Karisnan K, Mahzabin T, Bakker AJ, Song Y, Noble PB, Pillow JJ, et al.
    Am J Physiol Regul Integr Comp Physiol, 2018 04 01;314(4):R523-R532.
    PMID: 29212808 DOI: 10.1152/ajpregu.00150.2017
    The preterm diaphragm is functionally immature compared with its term counterpart. In utero inflammation further exacerbates preterm diaphragm dysfunction. We hypothesized that preterm lambs are more vulnerable to in utero inflammation-induced diaphragm dysfunction compared with term lambs. Pregnant ewes received intra-amniotic (IA) injections of saline or 10 mg lipopolysaccharide (LPS) 2 or 7 days before delivery at 121 days (preterm) or ∼145 days (term) of gestation. Diaphragm contractile function was assessed in vitro. Plasma cytokines, diaphragm myosin heavy chain (MHC) isoforms, and oxidative stress were evaluated. Maximum diaphragm force in preterm control lambs was significantly lower (22%) than in term control lambs ( P < 0.001). Despite similar inflammatory cytokine responses to in utero LPS exposure, diaphragm function in preterm and term lambs was affected differentially. In term lambs, maximum force after a 2-day LPS exposure was significantly lower than in controls (by ~20%, P < 0.05). In preterm lambs, maximum forces after 2-day and 7-day LPS exposures were significantly lower than in controls (by ~30%, P < 0.05). Peak twitch force after LPS exposure was significantly lower in preterm than in controls, but not in term lambs. In term lambs, LPS exposure increased the proportion of MHC-I fibers, increased twitch contraction times, and increased fatigue resistance relative to controls. In preterm diaphragm, the cross-sectional area of embryonic MHC fibers was significantly lower after 7-day versus 2-day LPS exposures. We conclude that preterm lambs are more vulnerable to IA LPS-induced diaphragm dysfunction than term lambs. In utero inflammation exacerbates diaphragm dysfunction and may increase susceptibility to postnatal respiratory failure.
    Matched MeSH terms: Muscle Weakness/blood; Muscle Weakness/chemically induced*; Muscle Weakness/physiopathology
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