MyMedR

Displaying publications 21 - 29 of 29 in total

Abstract:

Sort:

Fulltext Review on Cross Talk between Neurotransmitters and Neuroinflammation in Striatum and Cerebellum in the Mediation of Motor Behaviour

Abg Abd Wahab DY, Gau CH, Zakaria R, Muthu Karuppan MK, A-Rahbi BS, Abdullah Z, et al.

Biomed Res Int, 2019;2019:1767203.
PMID: 31815123 DOI: 10.1155/2019/1767203

Neurological diseases particularly Alzheimer's disease (AD), Parkinson's disease (PD), stroke, and epilepsy are on the rise all around the world causing morbidity and mortality globally with a common symptom of gradual loss or impairment of motor behaviour. Striatum, which is a component of the basal ganglia, is involved in facilitating voluntary movement while the cerebellum is involved in the maintenance of balance and coordination of voluntary movements. Dopamine, serotonin, gamma-aminobutyric acid (GABA), and glutamate, to name a few, interact in regulating the excitation and inhibition of motor neurons. In another hand, interestingly, the motor loss associated with neurological diseases is possibly resulted from neuroinflammation induced by the neuroimmune system. Toll-like receptors (TLRs) are present in the central nervous system (CNS), specifically and primarily expressed in microglia and are also found on neurons and astrocytes, functioning mainly in the regulation of proinflammatory cytokine production. TLRs are always found to be associated or involved in the induction of neuroinflammation in neurodegenerative diseases. Activation of toll-like receptor 4 (TLR4) through TLR4 agonist, lipopolysaccharide (LPS), stimulation initiate a signaling cascade whereby the TLR4-LPS interaction has been found to result in physiological and behavioural changes including retardation of motor activity in the mouse model. TLR4 inhibitor TAK-242 was reflected in the reduction of the spinal cord pathology along with the motor improvement in ALS mouse. There is cross talk with neuroinflammation and neurochemicals. For example, TLR4 activation by LPS is noted to release proinflammatory cytokines, IL-1β, from microglia that subsequently suppresses GABA receptor activities at the postsynaptic site and reduces GABA synthesis at the presynaptic site. Glial glutamate transporter activities are also found to be suppressed, showing the association between TLR4 activation and the related neurotransmitters and corresponding receptors and transporters in the event of neuroinflammation. This review is helpful to understand the connection between neurotransmitter and neuroinflammation in striatum- and cerebellum-mediated motor behaviour.

Matched MeSH terms: Motor Neurons/drug effects*
Nerve conduction study of healthy Asian Malays: the influence of age on median, ulnar, and sural nerves

Awang MS, Abdullah JM, Abdullah MR, Tahir A, Tharakan J, Prasad A, et al.

Med Sci Monit, 2007 Jul;13(7):CR330-2.
PMID: 17599028

Nerve conduction study is essential in the diagnosis of focal neuropathies and diffuse polyneuropathies. There are many factors that can affect nerve conduction velocity, and age is one of them. Most of the many studies of this effect, and the values from them, were on Caucasian subjects. Therefore, this study was designed to investigate the effect of age on conduction velocity among healthy Asian Malay subjects by analyzing its influence on the median, ulnar, and sural nerves.

Matched MeSH terms: Motor Neurons/metabolism
Fulltext Facial nerve palsy in a child: Bell’s palsy? Think again!

Jo Ee Sam, Nasser Abdul Wahab, Priya Sharda

Malays Fam Physician, 2017;12(3):30-32.
MyJurnal

Introduction: Half of facial paralysis in children is idiopathic at origin. However, dismissing facial
paralysis as being idiopathic without a thorough history and meticulous examination could be
disastrous as illustrated by this case.

Case report: We report a case of sphenoid wing meningioma in a 4-year-old girl. She first
presented with only facial asymmetry that was noticed by her mother. Examination suggested a
left upper motor neuron facial nerve palsy. A sphenoid wing meningioma was found on magnetic
resonance imaging (MRI) of her brain. She underwent craniotomy and total tumour excision.
Histopathological examination of the tumour showed a grade 1 transitional type meningioma.
Meningiomas in children are rare compared to the adult population. Presentations in children
may be delayed due to their inability to recognise or communicate abnormalities. Distinguishing
between upper and lower motor neuron facial palsy is crucial in decision making for facial paralysis
in children.

Matched MeSH terms: Motor Neurons
Histological analysis of motoneuron survival and microglia inhibition after nerve root avulsion treated with nerve graft implantation and minocycline: an experimental study

Wu W, Jafri M Abdullah, Faizul H Ghazali

Sains Malaysiana, 2016;45:1641-1648.

Motor vehicle accidents are the most common cause of injuries involving avulsion of the brachial plexus in humans,
resulting in debilitating motor dysfunction. Lack of an established animal model to test drug treatments hinders
the introduction of new pharmacological agents. Avulsion injury of cervical ventral roots can be replicated in rats,
resulting in a progressive loss of the motoneurons and increase in neurotoxic expression of microglia. This is a report
on the effect of prompt nerve implantation and minocycline treatment on the suppression of microglia activation and
survival of motoneurons. 20 adult female Sprague-Dawley rats were used for this study, which was approved by the
Animal Ethical Committee, USM (approval number /2011/(73)(346)). The animals underwent surgical avulsion of the
C6 nerve root, followed by reimplantation with peripheral nerve graft and treatment with intraperitoneal minocycline.
At 6 weeks postoperatively, immunohistochemistry using primary antibody Iba1 (microglia) and nicotinamide adenine
dinucleotide phosphate diaphorase (NADPh) with neutral-red staining (motoneuron) under flourescence microscopy
was performed at the C6 spinal cord segment and then quantified. This study showed significant reduction of microglia
expression in the study group; mean ranks of control and study group were 15.2 and 11.6, respectively; U=9.5, Z=3.02,
p<0.05. However, this did not translate into a significant increase of motoneuron survival in the combined group;
the mean ranks of control and study group were 40.6 and 41.6, respectively; U=44.5, Z=-.0378, p>0.05. This may
be due to the effect of the surgery; the surgery has the potential to cause additional trauma to the cord parenchyma,
leading to further motoneuron loss and an increase in scarring around the avulsed region, thus impeding regeneration
of the motoneuron.

Matched MeSH terms: Motor Neurons
Fulltext Facial nerve palsy in a child: Bell's palsy? Think again!

Sam JE, Priya S, Nasser AW

Malays Fam Physician, 2017;12(3):30-32.
PMID: 29527278

Introduction: Half of facial paralysis in children is idiopathic at origin. However, dismissing facial paralysis as being idiopathic without a thorough history and meticulous examination could be disastrous as illustrated by this case.

Case report: We report a case of sphenoid wing meningioma in a 4-year-old girl. She first presented with only facial asymmetry that was noticed by her mother. Examination suggested a left upper motor neuron facial nerve palsy. A sphenoid wing meningioma was found on magnetic resonance imaging (MRI) of her brain. She underwent craniotomy and total tumour excision. Histopathological examination of the tumour showed a grade 1 transitional type meningioma. Meningiomas in children are rare compared to the adult population. Presentations in children may be delayed due to their inability to recognise or communicate abnormalities. Distinguishing between upper and lower motor neuron facial palsy is crucial in decision making for facial paralysis in children.

Matched MeSH terms: Motor Neurons
Fulltext The Effects of Minocycline on Spinal Root Avulsion Injury in Rat Model

Chin TY, Kiat SS, Faizul HG, Wu W, Abdullah JM

Malays J Med Sci, 2017 Mar;24(1):31-39.
PMID: 28381927 MyJurnal DOI: 10.21315/mjms2017.24.1.4

BACKGROUND: The neuroprotective role of minocycline in the treatment of brachial plexus injury is controversial.
OBJECTIVE: To study the neuroprotective effect of minocycline via different routes in adult Sprague Dawley rats with brachial plexus injury.
METHODS: The C7 nerve roots of the animals were avulsed via an anterior extravertebral approach. Traction force was used to transect the ventral motor nerve roots at the preganglionic level. Intraperitoneal and intrathecal minocycline (50 mg/kg for the first week and 25 mg/kg for the second week) were administered to promote motor healing. The spinal cord was harvested six weeks after the injury, and structural changes following the avulsion injury and pharmacological intervention were analysed.
RESULTS: Motor neuron death and microglial proliferation were observed after the administration of minocycline via two different routes (intraperitoneal and intrathecal) following traumatic avulsion injury of the ventral nerve root. The administration of intraperitoneal minocycline reduced the microglia count but increased the motor neuron count. Intrathecal minocycline also reduced the microglial count, with a greater reduction than in the intraperitoneal group, but it decreased the motor neuron count.
CONCLUSIONS: Intraperitoneal minocycline increased motor neuron survival by inhibiting microglial proliferation following traumatic avulsion injury of the nerve root. The inhibitory effect was augmented by the use of intrathecal minocycline, in which the targeted drug delivery method increased the bioavailability of the therapeutic agent. However, motor neuron survival was impaired at a higher concentration of minocycline via the intrathecal route due to the more efficient method of drug delivery. Microglial suppression via minocycline can have both beneficial and damaging effects, with a moderate dose being beneficial as regards motor neuron survival but a higher dose proving neurotoxic due to impairment of the glial response and Wallerian degeneration, which is a pre-requisite for regeneration.

Matched MeSH terms: Motor Neurons
Fulltext Paclitaxel Inhibits Expression of Neuronal Nitric Oxide Synthase and Prevents Mitochondrial Dysfunction in Spinal Ventral Horn in Rats After C7 Spinal Root Avulsion

Sim SK, Tan YC, Tee JH, Yusoff AA, Abdullah JM

Turk Neurosurg, 2015;25(4):617-24.
PMID: 26242340 DOI: 10.5137/1019-5149.JTN.14035-15.1

This study evaluated the neuroprotective effect of intrathecally infused paclitaxel in the prevention of motoneuron death and mitochondrial dysfunction following brachial plexus avulsion injury.

Matched MeSH terms: Motor Neurons/drug effects
Fulltext Tocotrienol-Rich Vitamin E (Tocovid) Improved Nerve Conduction Velocity in Type 2 Diabetes Mellitus Patients in a Phase II Double-Blind, Randomized Controlled Clinical Trial

Chuar PF, Ng YT, Phang SCW, Koay YY, Ho JI, Ho LS, et al.

Nutrients, 2021 Oct 25;13(11).
PMID: 34836025 DOI: 10.3390/nu13113770

Diabetic peripheral neuropathy (DPN) is the most common microvascular complication of diabetes that affects approximately half of the diabetic population. Up to 53% of DPN patients experience neuropathic pain, which leads to a reduction in the quality of life and work productivity. Tocotrienols have been shown to possess antioxidant, anti-inflammatory, and neuroprotective properties in preclinical and clinical studies. This study aimed to investigate the effects of tocotrienol-rich vitamin E (Tocovid SuprabioTM) on nerve conduction parameters and serum biomarkers among patients with type 2 diabetes mellitus (T2DM). A total of 88 patients were randomized to receive 200 mg of Tocovid twice daily, or a matching placebo for 12 months. Fasting blood samples were collected for measurements of HbA1c, renal profile, lipid profile, and biomarkers. A nerve conduction study (NCS) was performed on all patients at baseline and subsequently at 2, 6, 12 months. Patients were reassessed after 6 months of washout. After 12 months of supplementation, patients in the Tocovid group exhibited highly significant improvements in conduction velocity (CV) of both median and sural sensory nerves as compared to those in the placebo group. The between-intervention-group differences (treatment effects) in CV were 1.60 m/s (95% CI: 0.70, 2.40) for the median nerve and 2.10 m/s (95% CI: 1.50, 2.90) for the sural nerve. A significant difference in peak velocity (PV) was also observed in the sural nerve (2.10 m/s; 95% CI: 1.00, 3.20) after 12 months. Significant improvements in CV were only observed up to 6 months in the tibial motor nerve, 1.30 m/s (95% CI: 0.60, 2.20). There were no significant changes in serum biomarkers, transforming growth factor beta-1 (TGFβ-1), or vascular endothelial growth factor A (VEGF-A). After 6 months of washout, there were no significant differences from baseline between groups in nerve conduction parameters of all three nerves. Tocovid at 400 mg/day significantly improve tibial motor nerve CV up to 6 months, but median and sural sensory nerve CV in up to 12 months of supplementation. All improvements diminished after 6 months of washout.

Matched MeSH terms: Motor Neurons/drug effects
Fulltext Ischaemic haemorrhagic stroke in a child with new onset type 1 diabetes mellitus

Mohd Nor NS, Fong CY, Rahmat K, Vanessa Lee WM, Zaini AA, Jalaludin MY

Eur Endocrinol, 2018 Apr;14(1):59-61.
PMID: 29922355 DOI: 10.17925/EE.2018.14.1.59

Cerebral oedema is the most common neurological complication of diabetic ketoacidosis (DKA). However, ischaemic and haemorrhagic brain injury has been reported infrequently. A 10-year old girl who was previously well presented with severe DKA. She was tachycardic with poor peripheral perfusion but normotensive. However, two fast boluses totalling 40 ml/kg normal saline were given. She was transferred to another hospital where she was intubated due to drowsiness. Rehydration fluid (maintenance and 48-hour correction for 7.5% dehydration) was started followed by insulin infusion. She was extubated within 24 hours of admission. Her ketosis resolved soon after and subcutaneous insulin was started. However, about 48 hours after admission, her Glasgow Coma Scale score dropped to 11/15 (E4M5V2) with expressive aphasia and upper motor neuron signs. One dose of mannitol was given. Her symptoms improved gradually and at 26-month follow-up she had a near-complete recovery with only minimal left lower limb weakness. Serial magnetic resonance imaging brain scans showed vascular ischaemic injury at the frontal-parietal watershed regions with haemorrhagic transformation. This case reiterates the importance of monitoring the neurological status of patient's with DKA closely for possible neurological complications including an ischaemic and haemorrhagic stroke.

Matched MeSH terms: Motor Neurons