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Genotypic Characteristics (genotypic + characteristic)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

The MTHFR C677T polymorphism confers a high risk for stroke in both homozygous and heterozygous T allele carriers with Type 2 diabetes

DIABETIC MEDICINE, Issue 5 2006
M. P. Hermans
Abstract Objective Individuals with Type 2 diabetes are at increased risk of stroke. Plasma homocysteine (tHcy) is an independent risk factor for cardiovascular (CV) disease. The methylene,tetrahydrofolate reductase (MTHFR) gene polymorphism (thermolabile variant C677T) is associated with CV risk, partly as a result of increased Hcy, especially in homozygous subjects. Aim To relate the occurrence of the MTHFR polymorphism with stroke prevalence by examining allelic frequency and genotype distribution in 165 subjects with Type 2 diabetes studied for the presence of thermolabile C677T MTHFR mutation. Results Mean age was 67.7 years, and tHcy 18.2 µmol/l. T allele frequency was 38.5%. MTHFR genotypes were: normal (CC) 40%; heterozygous (CT) 43%; homozygous (TT) 17%. Serum levels of folic acid and B12 vitamin were within normal limits. Stroke prevalence was 14%. Sixty-four per cent of stroke-free subjects had the normal C allele vs. 46% in stroke subjects. The frequencies of genotypes (CC-CT-TT) were (%): 44-41-15 in stroke-free vs. 17-57-26 in stroke patients. Coronary (CAD) and peripheral artery disease (PAD) were common in all groups, with no differences according to genotypes. Stroke prevalence was markedly higher in genotypes CT and TT (18 and 21%) compared with CC (6%). Mean tHcy levels were higher in TT subjects. Conclusion The allelic frequency of C677T MTHFR mutation in Type 2 diabetes subjects with stroke is markedly different from that of subjects without stroke. Genotypic characteristics suggest that C677T MTHFR mutation confers a higher risk for stroke to both homozygous and heterozygous T allele carriers that cannot be ascribed solely to raised tHcy and/or lower folate status in CT subjects, nor to phenotypic expression of conventional risk factors for stroke. The impact of the MTHFR polymorphism on stroke may result from T allele-linked deleterious effects, or C allele-linked protection. Confirmatory studies are warranted, as this cohort was not randomly selected, and a type 1 error cannot be ruled out. [source]

The new mycobacteria: an update

FEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2006
Enrico Tortoli
Abstract The continuous evolution of mycobacterial taxonomy may represent a source of confusion for laboratories and clinicians. Apart from the obvious pathogenic strains of the Mycobacterium tuberculosis complex, Mycobacterium leprae and Mycobacterium ulcerans, the role of other mycobacteria may be associated with varying conditions ranging from contamination to specific disease processes. Of the more than 120 mycobacterial species recognized currently, very few have not been reported as pathogenic in humans or animals. Although the attempt to keep pace with the steadily increasing number of mycobacterial species seems hopeless, a careful review of the recent literature relevant to the newly described species may be advantageous. The aim of this present update is to provide epidemiological and clinical information along with major phenotypic and genotypic characteristics of the species described in the last 3 years. [source]

From expert opinion to evidence-based: changes in the gold standard of primary brain tumour diagnosis,

THE JOURNAL OF PATHOLOGY, Issue 1 2007
JM Kros
Abstract Since 1997, significant progress has been made in the WHO guidelines for the diagnosis of primary tumours of the central nervous system. A large group of international experts was involved in editing the content; consensus on definitions and classifications was sought; and updated findings of genomic investigations were included. Nevertheless, significant inter-observer variability still exists in the histopathological diagnosis of several tumour types. The challenge for the near future is to identify histological and genotypic characteristics with prognostic or predictive value. With that aim, testing histological or molecular parameters in prospective clinical studies is indicated. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [source]

An epidemiologic analysis of staphylococcus aureus-associated keratitis in Boston

ACTA OPHTHALMOLOGICA, Issue 2009
I BEHLAU
Purpose S. aureus is a normal commensal of the human skin and nasopharynx. It is therefore of interest to determine whether S. aureus keratitis is caused by a subset of these organisms. In this study, the phenotypic and genotypic characteristics of S.aureus keratitis isolates were analyzed. Methods All S. aureus clinical isolates were prospectively collected over a 24 month period at the MEEI (2006-2008). The diagnosis of clinical keratitis and associated risk factors was by medical record review. Keratitis-associated S. aureus strains were assessed for: 1) antibiotic susceptibility, 2) biofilm robustness by gentian violet staining using an in vitro microtiter plate assay, and 3) genetic lineage by multi-locus sequence typing (MLST). Results 26 cases of keratitis were identified from the 600 S. aureus clinical isolates. Risk factors associated with S.aureus keratitis included trauma, prior surgery, soft contact lens wear, and the presence of a foreign body. Ocular surface disease does not appear to be an independent risk factor. All 26 isolates were tetracycline- and trimethoprim-sulfamethoxazole- sensitive. All the MRSA strains were found to be ciprofloxacin-resistant (10/26). Nearly one-half of all the S.aureus keratitis-associated isolates were caused by a single clone, ST5. Both methicillin sensitive and resistant S. aureus strains were represented within ST5. Conclusion These results suggest that there may be specific S.aureus lineages which possess phenotypic and genotypic characteristics that enable S. aureus to more effectively cause sight-threatening keratitis. Future work will examine their virulence traits and a comparison to commensal S.aureus strains. [source]