Abdul Majeed Al-Drees

Rundataxin, a novel protein with RUN and diacylglycerol binding domains, is mutant in a new recessive ataxia

We have identified a novel form of recessive ataxia that segregates in three children of a large consanguineous Saudi Arabian family. The three patients presented with childhood onset gait and limb ataxia, dysarthria and had limited walking without aid into their teenage years. Two patients developed epilepsy at 7 months without relapse after treatment, and mental retardation. Linkage studies allowed us to identify a single locus that segregated with the disease on chromosome 3q28-qter. Mutation screening of all coding sequences revealed a single nucleotide deletion, 2927delC, in exon 19 of the KIAA0226 gene, which results in a frame shift of the C-terminal domain (p.Ala943ValfsX146). The KIAA0226 gene encodes a protein that we named rundataxin, with two conserved domains: an N-terminal RUN domain and a C-terminal domain containing a diacylglycerol binding-like motif. The closest paralogue of rundataxin, the plekstrin homology domain family member M1, has been shown to colocalize with Rab7, a small GTPase associated with late endosomes/lysosomes, suggesting that rundataxin may also be associated with vesicular trafficking and signalling pathways through its RUN and diacylglycerol binding-like domains. The rundataxin pathway appears therefore distinct from the ataxia pathways involving deficiency in mitochondrial or nuclear proteins and broadens the range of mechanisms leading to recessive ataxias.

New Findings in a Global Approach to Dissect the Whole Phenotype of PLA2G6 Gene Mutations

Mutations in PLA2G6 gene have variable phenotypic outcome including infantile neuroaxonal dystrophy, atypical neuroaxonal dystrophy, idiopathic neurodegeneration with brain iron accumulation and Karak syndrome. The cause of this phenotypic variation is so far unknown which impairs both genetic diagnosis and appropriate family counseling. We report detailed clinical, electrophysiological, neuroimaging, histologic, biochemical and genetic characterization of 11 patients, from 6 consanguineous families, who were followed for a period of up to 17 years. Cerebellar atrophy was constant and the earliest feature of the disease preceding brain iron accumulation, leading to the provisional diagnosis of a recessive progressive ataxia in these patients. Ultrastructural characterization of patients’ muscle biopsies revealed focal accumulation of granular and membranous material possibly resulting from defective membrane homeostasis caused by disrupted PLA2G6 function. Enzyme studies in one of these muscle biopsies provided evidence for a relatively low mitochondrial content, which is compatible with the structural mitochondrial alterations seen by electron microscopy. Genetic characterization of 11 patients led to the identification of six underlying PLA2G6 gene mutations, five of which are novel. Importantly, by combining clinical and genetic data we have observed that while the phenotype of neurodegeneration associated with PLA2G6 mutations is variable in this cohort of patients belonging to the same ethnic background, it is partially influenced by the genotype, considering the age at onset and the functional disability criteria. Molecular testing for PLA2G6 mutations is, therefore, indicated in childhood-onset ataxia syndromes, if neuroimaging shows cerebellar atrophy with or without evidence of iron accumulation.

Effect of Duration of Exposure to Cement Dust on Respiratory Function of Non-Smoking Cement Mill Workers

This study aimed to determine the effect of long term exposure to cement dust on lung function in non-smoking cement mill workers. This is a cross-sectional study of respiratory functions. Spirometry was performed in 100 apparently healthy volunteers; 50 non-smoking cement mill workers and 50 non-smoking un-exposed subjects. Based on the duration of exposure, cement mill workers were divided into three groups, less than 5, 5–10 and greater than 10 years. All subjects were individually matched for age, height, weight, and socioeconomic status. Pulmonary function test was performed by using an electronic spirometer. Significant reduction was observed in the mean values of Forced Vital Capacity (FVC), Forced Expiratory Volume in one second (FEV1), Peak Expiratory Flow (PEF) and Maximal Voluntary Ventilation in cement mill workers who had been working in the cement industry for more than 10 years compared to their matched un-exposed group. Lung functions in cement mill workers were significantly impaired and results show a long term duration response effect of years of exposure to cement dust on lung functions.

Tamoxifen protects clonal mouse hippocampal (HT-22) cells against neurotoxins-induced cell death

In the present work using an established clonal mouse hippocampal (HT-22) cell line, we have examined whether the estrogen antagonist tamoxifen antagonizes the observed neuroprotective effects of estrogen against glutamate and amyloid beta protein neurotoxicity. Results obtained suggest that like estrogen, tamoxifen protects HT-22 cells against both 5mM glutamate and 2 microM amyloid beta protein induced cell death in a concentration dependent manner. Optimum protection was obtained at 500 nM tamoxifen. Tamoxifen was found to offer more potent protection at this dose against amyloid beta protein induced neurotoxicity when compared with glutamate neurotoxicity. We were unable to detect either estrogen receptor (ER)--ER alpha or ER beta presence in HT-22 cells using western blot technique. However, amyloid beta protein treatment significantly increases total glucocorticoid receptors (GRs) as determined by western blot technique, while prior treatment with estrogen or tamoxifen followed by amyloid beta protein resulted in the reduction of total GRs to the levels comparable to that observed for the control untreated cells. In addition, using confocal immunoflourescence microscopy technique, we observed that 20 h of treatment with 2 microM amyloid beta protein resulted in enhanced nuclear localization of GRs in HT-22 cells as compared to control untreated cells or 500 nM tamoxifen alone treated cells. Interestingly, 500 nM tamoxifen treatments for 24h, followed by 20 h treatment with 2 microM amyloid beta protein resulted in dramatic reduction in GRs nuclear localization. In conclusion, tamoxifen (i) protects HT-22 cells against amyloid beta protein neurotoxicity and (ii) neuroprotective effect is independent of ERs.

Inhibition of Proinflammatory Cytokines by Sch79797, a Selective Protease-activated Receptor 1 Antagonist, Protects Rat Kidney Against Ischemia-reperfusion Injury

Renal ischemia-reperfusion injury (I/R) is the most common cause of acute renal failure. It is partially mediated by thrombin as it is attenuated by thrombin inhibition or deletion of its receptor protease-activated receptor 1 (PAR1). However, the role of PAR1 in renal I/R injury needs to be further elucidated. The present study investigated the effect of PAR1 antagonist, SCH79797 (SCH), on renal protection and downstream effectors involved. Male Wistar rats were pretreated with SCH (25 &mgr;g/kg i.p.) or vehicle, 15 min before 45 min of clamping of left renal pedicle after right nephrectomy. To investigate the involvement of phosphatidylinositol 3-kinase (PI3K)/Akt, a group of rats was subjected to pretreatment with an inhibitor of PI3K/Akt (LY 29004, 3 mg/kg i.p.) before renal ischemia and SCH treatment. A sham-operated group served as control and received saline. All rats were killed 24 h after reperfusion or sham operation, and blood samples collected and kidney tissues processed either for immunostaining and histological assessment or for biochemical analysis. SCH79797 markedly attenuated kidney damage histologically and by improving serum creatinine. Both plasma and protein expression of P selectin were markedly reduced as well as neutrophil infiltration, cytokine-induced neutrophil chemoattractant 1, and tumor necrosis factor &agr;. These protective effects of blocking PAR1 receptor were abolished by preadministration of LY29004. These results suggest that PAR1 mediates renal I/R injury and that blocking PAR1 using SCH limits renal injury by an anti-inflammatory effect possibly signaling via PI3K/Akt. ABBREVIATIONS I/R—ischemia-reperfusion PAR1—protease-activated receptor 1

Camel milk attenuates the biochemical and morphological features of diabetic nephropathy: Inhibition of Smad1 and collagen Type IV synthesis

Diabetic nephropathy (DN) is a common microvascular complication of diabetes mellitus (DM) that worsens its morbidity and mortality. There is evidence that camel milk (CM) improves the glycemic control in DM but its effect on the renal complications especially the DN remains unclear. Thus the current study aimed to characterize the effects of CM treatment on streptozotocin (STZ)-induced DN. Using STZ-induced diabetes, we investigated the effect of CM treatment on kidney function, proteinuria, renal Smad1, collagen type IV (Col4), blood glucose, insulin resistance (IR), lipid peroxidation, the antioxidant superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH). In addition renal morphology was also examined. The current results showed that rats with untreated diabetes exhibited marked hyperglycemia, IR, high serum urea and creatinine levels, excessive proteinuria, increased renal Smad1 and Col4, glomerular expansion, and extracellular matrix deposition. There was also increased lipid peroxidation products, decreased antioxidant enzyme activity and GSH levels. Camel milk treatment decreased blood glucose, IR, and lipid peroxidation. Superoxide dismutase and CAT expression, CAT activity, and GSH levels were increased. The renoprotective effects of CM were demonstrated by the decreased serum urea and creatinine, proteinuria, Smad1, Col4, and preserved normal tubulo-glomerular morphology. In conclusion, beside its hypoglycemic action, CM attenuates the early changes of DN, decreased renal Smad1 and Col4. This could be attributed to a primary action on the glomerular mesangial cells, or secondarily to the hypoglycemic and antioxidant effects of CM. The protective effects of CM against DN support its use as an adjuvant anti-diabetes therapy.

Estrogen protects cardiac myogenic (H9c2) rat cells against lethal heat shock-induced cell injury: modulation of estrogen receptor alpha, glucocorticoid receptors, heat shock protein 70, and iNOS.

In the present study we have established that exposure of rat cardiac myoblasts (H9c2 cells) to 46°C for 1 hour (lethal heat shock) resulted in optimal cell injury as determined by lactate dehydrogenase release. Pretreatment of H9c2 cells for 24 hours with 17β-estradiol significantly protects myoblasts against subsequent lethal heat shock exposure in a concentration-dependent manner with maximum protection obtained at 1 μM of 17β-estradiol. With Western blotting, it was observed that 17β-estradiol-protected cells had significantly higher levels of the estrogen receptor α and inducible heat shock protein 70 (hsp70) as well as inducible nitric oxide synthase (iNOS) levels compared with lethal heat shock-exposed cells. In contrast, lethal heat shock-exposed cells had significantly higher levels of total cellular glucocorticoid receptors (GR), both cytoplasmic and nuclear, compared with 17β-estradiol-protected cells. Immunofluorescence technique using confocal microscopy revealed nuclear localization of the glucocorticoid receptors (GR) in lethal heat shock-exposed H9c2 cells while 17β-estradiol-protected cells had primarily extranuclear localization of GR. We conclude that (1) 17β-estradiol protects H9c2 cells against lethal heat shock insult by a receptor-independent mechanism, and (2) the protective effects are likely mediated by modulation of GR, hsp 70, and iNOS expression.

The relationship between non-functioning distractors and item difficulty of multiple choice questions: A descriptive analysis

Objectives: This study investigates the relationship between the presence of non-functioning distractors (NFDs) and the difficulty index of multiple choice questions (MCQs). Materials and Methods: The number of NFDs and difficulty index were correlated for each MCQ of Family Medicine Examination, College of Medicine, King Saud University (KSU) in three consecutive years (2010, 2011 and 2012). Results: The MCQs with more NFDs showed high difficulty index as compared to MCQs having less NFDs. The pattern of increasing difficulty index was 1NFD Conclusion: MCQs with a higher number of NFDs are easier than those with lower number of NFDs.

Ophthalmic features of PLA2G6-related paediatric neurodegeneration with brain iron accumulation

Background Neurodegeneration with brain iron accumulation (NBIA) refers to genetically heterogenous paediatric neurodegenerative disorders characterised by basal ganglia iron deposition. One major cause is recessive mutations in the PLA2G6 gene. While strabismus and optic nerve pallor have been reported for PLA2G6-related disease, the ophthalmic phenotype is not carefully defined. In this study we characterise the ophthalmic phenotype of PLA2G6-related NBIA. Methods Prospective cohort study. Results The eight patients were 4–26 years old when examined. All had progressive cognitive and motor regression first noted between 9 months and 6 years of age that typically first manifested as difficulty walking (ataxia). Ophthalmic examination was sometimes limited by cognitive ability. Four of eight had exotropia, 7/7 bilateral supraduction defect, 5/7 poor convergence, 6/8 saccadic pursuit, 4/8 saccadic intrusions that resembled square-wave jerks, and 8/8 bilateral optic nerve head pallor. All patients lacked Bell phenomenon. Conclusions Upgaze palsy, although not a previously reported finding, was confirmed in all patients (except in one for whom assessment could not be performed) and thus can be considered part of the phenotype in children and young adults. Other frequent findings not previously highlighted were abnormal convergence, saccadic pursuit, and saccadic intrusions. Optic nerve head pallor and strabismus, previously reported findings in the disease, were found in 100% and 50% of our cohort, respectively, and the strabismus in our series was always exotropia. Taken together, these clinical findings may be helpful in distinguishing PLA2G6-related neurodegeneration from the other major cause of NBIA, recessive PANK2 mutations.

effectiveness of Auditory Integration Therapy in Autism spectrum Disorders—prospective study

Objectives: To determine the effectiveness of auditory integration training (AIT) in people with Autism Spectrum Disorders (ASD). Method: Seventy two subjects with ASD aged up to 17 years old (70 male and 2 females) were recruited for the study. All subjects were screened by Diagnostic and Statistical Manual of Mental Disorders, (DSM-IV), and assessed by CARS (Childhood Autism Rating Scale). Pre-intervention scores and post-intervention (3 and 6 months) scores were calculated for each child using CARS, Social Responsiveness Scale (SRS), and the Autism Treatment Evaluation Checklist (ATEC). Auditory integration training was performed over 2 week, 30 minutes, twice a day. Results: All subjects demonstrated improvement 3 and 6 months following the AIT. ASD subject showed 22% and 26% percentage improvement in SRS scoring 3 and 6 months respectively following the AIT intervention. Those changes were attributed to statistically significant changes in social awareness, social cognition, and social communication. Similar results were achieved with the ATEC check list: ASD subject showed 19.5% and 22.5% improvement 3 and 6 months following the AIT intervention, respectively. Those changes are due to statistically significant ( P , 0.05) improvement in speech, communication and sociability only. Conclusions: The results of this study support the therapeutic effects of auditory integration training on social awareness, social cognition, and social communication, as well as speech and communication.