Genetic association of catechol-O-methyltransferase val(158)met polymorphism in Saudi schizophrenia patients.

Schizophrenia is a complex neuropsychiatric disorder strongly associated with dopamine dysregulation. Catechol-O-methyl-transferase (COMT) is a candidate gene for schizophrenia that encodes an enzyme involved in the metabolic inactivation of dopamine. The COMT Val(158)Met polymorphism has been associated with schizophrenia and has significant inter- and intra-ethnic variations. We examined a possible association between the COMT Val(158)Met polymorphism and schizophrenia in Saudis, taking into account gender and functional symptoms. Saudi subjects including 172 unrelated schizophrenia patients and 177 matched controls were analyzed for allele and genotype distribution of the COMT Val(158)Met polymorphism. We found significant differences in allele and genotype frequencies between patients and controls. The frequencies of Met(158) allele (A) and genotype Val(158)Met (GA) were significantly higher in patients compared to those in controls. On the other hand, the frequencies of Val(158) allele (G) and genotype Val(158)Val (GG) were significantly higher in controls than those in patients. We found a significant association of the COMT Val(158)Met polymorphism with schizophrenia. Moreover, male patients with the COMT Val(158)Met polymorphism had increased risk for schizophrenia compared to female subjects. However, no association was noticed with the COMT Val(158)Met polymorphism and negative or positive symptoms of schizophrenia. These results provide evidence for a role of the COMT Val(158)Met polymorphism in the etiopathophysiology of schizophrenia in Saudi population. It appears that the association of the COMT Val(158)Met polymorphism with schizophrenia is mediated by gender.

Tumor necrosis factor-α and -ß genetic polymorphisms as a risk factor in Saudi patients with vitiligo.

Vitiligo is an acquired depigmentary disorder of the skin, characterized by multiple susceptibility loci and genetic heterogeneity. The etiology of vitiligo is unknown but several hypotheses, including an autoimmune origin, have been proposed. Tumor necrosis factor (TNF)-α, a pleiotropic proinflammatory cytokine, has been shown to play a critical role in several autoimmune diseases including vitiligo. The aim of present study was to determine the association of TNF-α and -ß gene polymorphisms with vitiligo in Saudi patients. TNF-α and -ß genes were amplified in 123 Saudi patients and 200 matched controls using polymerase chain reaction to search for polymorphisms involved at positions -308, and intron 1 +252. The frequency of the TNF-α (-308) GA genotype was higher and the frequencies of the GG and AA genotypes were significantly lower in vitiligo patients compared to controls. These findings suggested that genotype GA-positive individuals at position -308 of TNF-α are susceptible to vitiligo, whereas the GG and AA genotypes might exert a protective effect. The frequency of allele A (TNF-α 2-allele) was significantly higher and that of allele G (TNF-α 1-allele) was lower in vitiligo patients compared to controls, indicating an association of allele A with susceptibility to vitiligo in Saudi patients. The results of our examination of TNF-ß (intron 1 +252) polymorphisms showed a significant increase in the frequency of the GG genotype and allele G (TNF-ß 1-allele) in vitiligo patients, suggesting a susceptibility of the GG genotype and allele G for vitiligo. By contrast, the high frequency of the GA genotype in controls might indicate a protective effect. The results of the present study strongly support a link between TNF-α (-308) and -ß (intron 1 +252) polymorphisms and vitiligo in Saudi patients.

Non-invasive diagnosis of H pylori infection: evaluation of serological tests with and without current infection marker CIM.

AIM: To evaluate the performance of commercially available immunochromatographic (ICT) and immunoblot tests covering the current infection marker CIM and conventional ELISA for the diagnosis of H pylori infection in adult dyspeptic patients. METHODS: Consecutive non-treated dyspeptic patients undergoing diagnostic endoscopy were tested for H pylori infection by culture, rapid urease test, and histology of gastric biopsy specimens. Serum from 61 H pylori infected and 21 non-infected patients were tested for anti-H pylori IgG antibodies by commercial ELISA (AccuBind ELISA, Monobind, USA), ICT (Assure H pylori Rapid Test, Genelabs Diagnostics, Singapore), and immunoblot (Helico Blot 2.1, Genelabs Diagnostics, Singapore) assays. ICT and immunoblot kits cover CIM among other parameters and their performance with and without CIM was evaluated separately. RESULTS: Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of ELISA were 96.7%, 42.8%, 83.1%, 81.8%, and 82.9%, of ICT were 90.1%, 80.9%, 93.2%, 73.9%, and 87.8%, of ICT with CIM were 88.5%, 90.4%, 96.4%, 73.0%, and 89.0%, of immunoblot were 98.3%, 80.9%, 93.7%, 94.4%, and 93.9%, and of immunoblot with CIM were 98.3%, 90.4%, 96.7%, 95.0%, and 96.3%, respectively. CONCLUSION: Immunoblot with CIM had the best performance. ICT with CIM was found to be more specific and accurate than the conventional ELISA and may be useful for non-invasive diagnosis of H pylori infection.

Systemic lupus erythematosus and infections: a retrospective study in Saudis.

This study demonstrates demographic, clinical and laboratory characteristics with special reference to infections in Saudi patients with SLE. One-hundred and ninety-nine patients with SLE treated at Riyadh Armed Forces Hospital, Saudi Arabia over a period of 15 years (1990-2005) were retrospectively reviewed. There were 162 females and 37 males (4.4 : 1) with an average age of 35 years at onset of disease. Duration of diseases ranged from one to 23 years with a mean of 7.23 years. Some of the clinical characteristics of SLE patients observed were nephritis (53.7%), fever (53.26%), neuropsychological disorder (36.18%), malar/butterfly rash (27.6%), pulmonary disorder (22.6%), photosensitivity (21.6%), cardiac involvement (21.1%) and oral ulcers (19.09%). Infection was the major complication with 58.79% of SLE patient having suffered from various infections. A total of 22 species of pathogens including gram positive and gram negative bacteria, viruses and fungi were isolated from 117 SLE patients. Single to multiple episode of infection with various pathogens were recorded however, majority of patients harboured one or two species of pathogens. Bacterial infection was predominant (78.6%) followed by viral (28.2%) and fungal (28.2%) infections. Forty-four percent of SLE patients were found to be infected with organisms classified as opportunistic. The high incidence of infections in SLE patients may be attributed to the multiple intrinsic and extrinsic risk factors including deficiency of complement (C3 and C4), disease activity, renal impairment, use of glucocorticoid and cytotoxic drugs. It is concluded that more judicious use of corticosteroids and other immunosuppressive agents will be critical to limit the infections in SLE and a high alert and close monitoring of patients will ensure optimal patient outcome, both in terms of morbidity and mortality.

The effects of age, sex and breed of chicken on susceptibility to Clinostomum complanatum (Digenea: Clinostomatidae).

Susceptibility and development of Clinostomum complanatum in the chicken (Gallus gallus domesticus) have been studied. The progenetic metacercariae of C. complanatum developed into ovigerous worms in 3 days in the buccal cavity of the chicken and survived only 6-7 days in this experimental host. The susceptibility is influenced by the age, sex and breed/type of the host. Both percent susceptibility and recovery of the worms decreased with increase in the age of the host. The egg laying chickens were found to be least susceptible to the infection. Mature male chickens were more susceptible than the females. The single comb white Leghorn (SCWL) was found to be susceptible while the local type (LT) and the cross breed (SCWLxLT) were not susceptible to C. complanatum. The possible reasons for these variations have been discussed.

Chemical nature and mode of stabilization of eggshell/capsule of some cyclophyllidean cestodes.

The chemical nature and mode of stabilization of the eggshell/capsule of Moniezia expansa, Avitellina lahorea and Stilesia globipunctata have been investigated using histochemical techniques. In M. expansa where vitelline glands are present, the eggshell is stabilized by -S-S and -S-H linkages whereas in A. lahorea and S. globipunctata, the vitelline glands are absent and the double membranes, fibrous capsule and paruterine organ contain mainly elastokeratin-type structural protein. The possible role of the vitellaria in the presence or absence of eggshell and its thickness is discussed.