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Diseases Worldwide (diseases + worldwide)

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Medical Sciences75%

Selected Abstracts

Disruption of the Wolbachia surface protein gene wspB by a transposable element in mosquitoes of the Culex pipiens complex (Diptera, Culicidae)

INSECT MOLECULAR BIOLOGY, Issue 2 2007
Y. O. Sanogo
Abstract Culex pipiens quinquefasciatus Say and Culex pipiens pipiens Linnaeus are sibling species incriminated as important vectors of emerging and re-emerging infectious diseases worldwide. The two forms differ little morphologically and are differentiated mainly based upon ecological, behavioural, physiological and genetic traits. Within the North American zone of sympatry, populations of Cx. p. quinquefasciatus and Cx. p. pipiens undergo extensive introgression and hybrid forms have been reported in nature. Both Cx. p. quinquefasciatus and Cx. p. pipiens are infected with the endosymbiotic bacteria Wolbachia pipientis. Here, we report the presence of a transposable element belonging to the IS256 family (IS256wPip) associated with Wolbachia in both Cx. p. quinquefasciatus and Cx. p. pipiens populations. Using reverse transcriptase PCR and sequence analysis, we show that IS256wPip has disrupted the wspB locus, a paralogue of the Wolbachia outer membrane protein (wspA) gene. The inactivation of the wspB appears to be specific to Cx. p. quinquefasciatus and to hybrids of the two forms, and was not observed in the surveyed Cx. p. pipiens mosquitoes. Our results support the hypothesis of a different origin of North American Cx. p. quinquefasciatus and Cx. p. pipiens populations. The flux of mobile genetic elements in the Wolbachia wPip genome could explain the high level of crossing types observed among different Culex populations. The insertion of IS256wPip into wspB may comprise a genetic candidate for discriminating Wolbachia symbionts in Culex. [source]

MicroRNA Expression Profile in Lieber-DeCarli Diet-Induced Alcoholic and Methionine Choline Deficient Diet-Induced Nonalcoholic Steatohepatitis Models in Mice

ALCOHOLISM, Issue 10 2009
Angela Dolganiuc
Background:, Alcoholic and nonalcoholic steatohepatitis are leading causes of liver diseases worldwide. While of different etiology, these share common pathophysiological mechanisms and feature abnormal fat metabolism, inflammation and fibrosis. MicroRNAs (miRNA) are highly conserved noncoding RNAs that control gene expression at the post-transcriptional level either via the degradation of target mRNAs or the inhibition of translation. Each miRNA controls the expression of multiple targets; miRNAs have been linked to regulation of lipid metabolism and inflammation. Methods:, We fed Lieber-DeCarli alcohol or methionine-choline-deficient (MCD) diets to C57Bl6 and analyzed livers for histopathology, cytokines by ELISA, alanine aminotransferase (ALT) by biochemical assay, and microRNA profile by microarray. Results:, Both Lieber-DeCarli and MCD diets lead to development of liver steatosis, liver injury, indicated by increased ALT, and elevated levels of serum TNF,, suggesting that animal models portray the pathophysiological features of alcoholic and nonalcoholic fatty liver, respectively. We identified that Lieber-deCarli diet up-regulated 1% and down-regulated 1% of known miRNA; MCD diet up-regulated 3% and down-regulated 1% of known miRNA, compared to controls. Of miRNAs that changed expression levels, 5 miRNAs were common in alcoholic and nonalcoholic fatty livers: the expression of both miR-705 and miR-1224 was increased after Lieber-DeCarli or MCD diet feeding. In contrast, miR-182, miR-183, and miR-199a-3p were down-regulated in Lieber-deCarli feeding, while MCD diet lead to their up-regulation, compared to corresponding controls. Conclusions:, Our findings indicate etiology-specific changes in miRNA expression profile during steatohepatitis models, which opens new avenues for research in the pathophysiology of alcoholic and nonalcoholic fatty liver disease. [source]

Diagnosis of common dermatophyte infections by a novel multiplex real-time polymerase chain reaction detection/identification scheme

BRITISH JOURNAL OF DERMATOLOGY, Issue 4 2007
M. Arabatzis
Summary Background, In the absence of a functional dermatophyte-specific polymerase chain reaction (PCR), current diagnosis of dermatophytoses, which constitute the commonest communicable diseases worldwide, relies on microscopy and culture. This combination of techniques is time-consuming and notoriously low in sensitivity. Objectives, Recent dermatophyte gene sequence records were used to design a real-time PCR assay for detection and identification of dermatophytes in clinical specimens in less than 24 h. Patients and methods, Two assays based on amplification of ribosomal internal transcribed spacer regions and on the use of probes specific to relevant species and species-complexes were designed, optimised and clinically evaluated. One assay was for detecting the Trichophyton mentagrophytes species complex plus T. tonsurans and T. violaceum. The second assayed for the T. rubrum species complex, Microsporum canis and M. audouinii. Results, The analytical sensitivity of both assays was 0·1 pg DNA per reaction, corresponding to 2·5,3·3 genomes per sample. The protocol was clinically evaluated over 6 months by testing 92 skin, nail and hair specimens from 67 patients with suspected dermatophytosis. Real-time PCR detected and correctly identified the causal agent in specimens from which T. rubrum, T. interdigitale, M. audouinii or T. violaceum grew in culture, and also identified a dermatophyte species in an additional seven specimens that were negative in microscopy and culture. Conclusions, This highly sensitive assay also proved to have high positive and negative predictive values (95·7% and 100%), facilitating the accurate, rapid diagnosis conducive to targeted rather than empirical therapy for dermatophytoses. [source]

P2X7 and NRAMP1/SLC11 A1 gene polymorphisms in Mexican mestizo patients with pulmonary tuberculosis

CLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 3 2007
P. Niņo-Moreno
Summary Tuberculosis remains one of the most important infectious diseases worldwide. Several studies have suggested that genetic factors may affect susceptibility to tuberculosis, but the specific genes involved have not yet been fully characterized. NRAMP1/SLC11 A1 and P2X7 genes have been linked to increased risk for tuberculosis in some African and Asiatic populations. To explore the potential role of these genes in the susceptibility to pulmonary tuberculosis in a Mexican mestizo population, we evaluated the association of D543N and 3,-UTR polymorphisms in NRAMP1/SLC11 A1 and ,,762 and A1513C polymorphisms in P2X7 genes with the risk for tuberculosis. Polymerase chain reaction (PCR) amplification of genomic DNA followed by restriction fragment length polymorphism analysis, and allelic-specific PCR was employed. We found no significant differences in allelic frequency in NRAMP1/SLC11 A1 gene polymorphisms in 94 patients with tuberculosis compared to 100 healthy contacts. Similarly, no significant association of the P2X7,762 gene polymorphism with tuberculosis was detected. In contrast, the P2X7 A1513C polymorphism was associated significantly with tuberculosis (P = 0·02, odds ratio = 5·28, 95% CI, 0·99,37·69), an association that had not been reported previously. However, when the function of P2X7 was assessed by an l -selectin loss assay, we did not find significant differences in patients compared to healthy contacts or between PPD+ and PPD, control individuals. This study further supports the complex role of P2X7 gene in host regulation of Mycobacterium tuberculosis infection, and demonstrates that different associations of gene polymorphisms and tuberculosis are found in distinct racial populations. [source]