METHODS: One hundred sixty-six healthy Malaysians of different ethnicities (51.2% women, aged 21-77 years) underwent NCS using a standard protocol. Correlations of various factors to NCS were determined, and multiple linear regression analysis was used to develop predictive equations for each parameter.
RESULTS: Age and ethnicity were the commonest independent factors influencing NCS followed by gender, height, weight, and body mass index. Increasing age predicted a reduction in lower limb motor and all sensory nerve action potential amplitudes and decrease in motor and sensory (except sural) conduction velocities. Ethnic Indians had slower motor and sensory conduction velocities in several nerves and also had differences in action potential amplitudes.
CONCLUSIONS: NCS parameters in multi-ethnic Malaysians were influenced independently by various demographic and physical factors, including ethnicity. Muscle Nerve 54: 244-248, 2016.
METHODS: We performed a retrospective review of nerve biopsy reports from April 1998 to June 2021 of patients with peripheral neuropathies presenting to the Department of Pathology, University of Malaya Medical Centre, Kuala Lumpur, Malaysia. The diagnostic value of the biopsies was determined based on the criteria by Midroni and Bilbao as follows: contributive (essential and helpful), non-contributive and inadequate.
RESULTS: A total of 107 nerve biopsies were analysed. Sixty-four (60 %) were males and the mean age was 52 years, ranging from 13 to 86 years. Ninety-four (88 %) were sural nerve biopsies; and only one patient (1 %) each had superficial peroneal and superficial radial nerve biopsy. The indications for the procedure were vasculitis (34 %), peripheral neuropathy of unknown aetiology (34 %), amyloidosis (14 %) and chronic inflammatory demyelinating polyneuropathy (10 %). In 68 (63 %) biopsies, the diagnostic value was contributive. Of these, 28 (26 %) were essential and 40 (37 %) were helpful. In contrast, 35 (33 %) biopsies were non-contributive and 4 (4 %) were inadequate. In 66 % (71/107) of cases, the nerve biopsy did not reveal a definite pathological diagnosis. However, in the remainder, a diagnosis of vasculitis (18 %, 19/107), followed by amyloidosis (10 %, 11/107) could be determined. For 32/71 biopsies with undetermined pathological diagnosis, neuropathy remained cryptogenic in 22 % (7/32) upon follow up.
CONCLUSIONS: With the exception of vasculitis and amyloidosis, there is limited value in performing nerve biopsies in the evaluation of patients with peripheral neuropathy. However, this should be interpreted with caution as the number of patients with a clinical diagnosis of vasculitis and amyloidosis were relatively larger than patients with other diagnosis. Refinement and careful selection of cases are required to increase the diagnostic yield of nerve biopsy.
METHODS: Among the >2,500 patients in a local muscle biopsy database, patients with LSM were identified and their genomic DNA were extracted from muscle samples and peripheral blood. All 13 exons of the electron-transfer flavoprotein dehydrogenase gene (ETFDH) were subsequently sequenced. Fifty controls were included to determine the prevalence of identified mutations in the normal population.
RESULTS: Fourteen (82%) of the 17 LSM patients had MADD with ETFDH mutations. Twelve (86%) were Chinese and two were Malay sisters. Other unrelated patients reported that they had no relevant family history. Nine (64%) were females. The median age at onset was 18.5 years (interquartile range=16-37 years). All 14 demonstrated proximal limb weakness, elevated serum creatine kinase levels, and myopathic changes in electromyography. Three patients experienced a metabolic crisis at their presentation. Sanger sequencing of ETFDH revealed nine different variants/mutations, one of which was novel: c.998A>G (p.Y333C) in exon 9. Notably, 12 (86%) patients, including the 2 Malay sisters, carried a common c.250G>A (p.A84T) variant, consistent with the hotspot mutation reported in southern China. All of the patients responded well to riboflavin therapy.
CONCLUSIONS: Most of our Malaysian cohort with LSM had late-onset, riboflavin-responsive MADD with ETFDH mutations, and they demonstrated phenotypic and genetic features similar to those of cases reported in southern China. Furthermore, we report a novel ETFDH mutation and possibly the first ever MADD patients of Malay descent.
METHODS: We used transmission electron microscopy (TEM) to investigate post-mortem tissue sections of patients with clinical melioidosis to identify the localisation of a recently identified gut microbiome, B. pseudomallei within host cells. The intranuclear presence of B. pseudomallei was confirmed using transmission electron microscopy (TEM) of experimentally infected guinea pig spleen tissues and Live Z-stack, and ImageJ analysis of fluorescence microscopy analysis of in vitro infection of A549 human lung epithelial cells.
RESULTS: TEM investigations revealed intranuclear localization of B. pseudomallei in cells of infected human lung and guinea pig spleen tissues. We also found that B. pseudomallei induced actin polymerization following infection of A549 human lung epithelial cells. Infected A549 lung epithelial cells using 3D-Laser scanning confocal microscopy (LSCM) and immunofluorescence microscopy confirmed the intranuclear localization of B. pseudomallei.
CONCLUSION: B. pseudomallei was found within the nuclear compartment of host cells. The nucleus may play a role as an occult or transient niche for persistence of intracellular pathogens, potentially leading to recurrrent episodes or recrudescence of infection.