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Biomedical subjects

Ardeshir Bayat

Publications and source records attributed to Ardeshir Bayat.

12 recordsLinked to original sources
PubMed2005

Identification of a novel mitochondrial mutation in Dupuytren's disease using multiplex DHPLC.

Dupuytren's disease is a familial fibroproliferative disorder of late onset affecting the hands. It is extremely common in individuals of Northern European extraction. Genetic studies have yet to identify the genes involved in the formation of the disease. Mitochondria play a critical role in cell metabolism and apoptosis. It is known that defective mitochondria generate abnormally high levels of reactive oxygen species by means of electron leak and that antioxidant enzyme activities decrease with age in skin fibroblasts. Respiratory function of mitochondria is also impaired in aging human tissues. Oxidative stress and production of free radicals may be important factors in the pathogenesis of Dupuytren's disease. Mitochondrial genes are also included in the regulation of apoptosis. Diseased tissue contains large numbers of myo- fibroblasts, which disappear by apoptosis during normal wound healing. High numbers of mitochondria have been observed in fibroblasts derived from diseased tissue. In the light of this evidence, the mitochondrial genome represents a potential location for candidate susceptibility genes for this late-onset disorder. In this study, the authors investigated the presence of mutations within the mitochondrial genome in 40 subjects; 20 Caucasian Dupuytren's disease patients with a maternally transmitted inheritance pattern and 20 control subjects were matched for age, sex, and race using a multiplex denaturing high-performance liquid chromatography approach. A hitherto unknown heteroplasmic mutation located within the mitochondrial 16s rRNA region was evident in 90 percent of patients and absent from all control subjects (p < 0.001; chi2 = 16.1). This mutation may be important in the pathogenesis of Dupuytren's disease.

Adult↗
PubMed2004

Genetic susceptibility to keloid disease: transforming growth factor beta receptor gene polymorphisms are not associated with keloid disease.

Keloid disease (KD) is an abnormal form of scarring with a familial predisposition. Genetic studies have yet to identify the genes involved in KD. Transforming growth factor beta (TGF-beta) has multiple cellular activities including cellular proliferation, differentiation and extracellular matrix production. TGF-beta family members such as TGF-beta(1) and TGF-beta(2) are known to be involved in KD formation. However, we previously demonstrated a lack of association between common TGF-beta(1) and TGF-beta(2) polymorphisms and KD. Other studies have implicated TGF-beta receptors in KD pathogenesis. TGF-beta receptors were therefore selected as candidate-susceptibility genes for this condition. Single-nucleotide polymorphisms (SNPs) in TGF-beta receptors I, II and III (TGF-betaRI, TGF-betaRII and TGF-betaRIII) were identified and investigated for association with the risk of developing KD. A polymerase chain reaction-restriction fragment length polymorphism method was used for genotyping novel and known TGF-beta receptor polymorphisms. DNA samples from 92 KD cases and 181 controls were examined. There were no statistically significant differences in genotype or allele frequency distributions between cases and controls for the TGF-beta receptor SNPs. Therefore, these TGF-beta receptor polymorphisms are unlikely to be associated with keloid scarring. It is possible that other SNPs in other TGF-beta family members are associated with KD. To our knowledge, this is the first report of a case-control association study with KD and TGF-beta receptor gene polymorphisms.

Case-Control Studies↗
PubMed2003

Genetic susceptibility to keloid disease and hypertrophic scarring: transforming growth factor beta1 common polymorphisms and plasma levels.

Keloid disease and hypertrophic scars are dermal tumors that are often familial and typically occur in certain races. Their exact etiology is still unknown. Transforming growth factor beta1 (TGF-beta1) plays a central role in wound healing and fibrosis and has been implicated in the pathogenesis of keloid disease and hypertrophic scar. The aims of this study were to measure the plasma level of TGF-beta1 in patients compared with controls, and to investigate the association of five common single nucleotide polymorphisms in TGF-beta1 with the risk of keloid disease and hypertrophic scar formation. Platelet-poor plasma levels of TGF-beta1 in 60 patients (15 with hypertrophic scar and 45 with keloid disease) and 18 controls were measured using an enzyme-linked immunoabsorbent assay technique. A polymerase chain reaction-restriction fragment length polymorphism method was used for genotyping TGF-beta1 polymorphisms. DNA samples from 133 patients (101 with keloid disease and 32 with hypertrophic scar) and 200 controls were examined. All patients and controls were Caucasians of Northern European extraction. There was no statistically significant difference in TGF-beta1 plasma levels between patients with keloid disease and hypertrophic scar and controls. There was also no statistically significant difference in genotype or allele frequency distributions between patients and controls for codons 10, 25, and 263 and for -509 and -800 single nucleotide polymorphisms of the TGF-beta1 gene. These results suggest that TGF-beta1 plasma levels and common polymorphisms are not associated with a risk of keloid disease and hypertrophic scar formation. This lack of association may be significant in view of the importance attached to the role of TGF-beta1 in dermal scarring. To the authors' knowledge, this is the first report of a case-control association study in keloid disease and hypertrophic scars using any single nucleotide polymorphisms.

Adolescent↗
PubMed2003

Genetic susceptibility to dupuytren disease: association of Zf9 transcription factor gene.

Transforming growth factor beta 1 (TGF-beta 1) is a key fibrogenic cytokine that has been shown to stimulate fibroblast proliferation and extracellular matrix deposition and has been implicated in the pathogenesis of Dupuytren disease. Zf9 is a transcription factor that increases TGF-beta 1 expression in tissue. The authors previously demonstrated a lack of association between common TGF-beta 1 and TGF-beta 2 polymorphisms and Dupuytren disease. Therefore, Zf9 transcription factor represents an additional candidate susceptibility gene for investigating hereditary predisposition to Dupuytren disease. Dupuytren disease, or Dupuytren contracture, is a progressive and recurrent fibroproliferative disease of unknown etiology that affects the human hands. It is often a familial disorder affecting Northern European Caucasians. Genes implicated in the development of Dupuytren disease have not yet been found. Using a polymerase chain reaction-restriction fragment polymorphism method, the authors genotyped a novel single nucleotide polymorphism in the 3' untranslated region of the Zf9 gene. A case-control association study of 138 patients with Dupuytren disease versus 255 controls demonstrated a statistically significant difference in the genotype and allele frequencies between patients and controls for Zf9 gene polymorphism. Presence of the G allele versus the A allele is associated with an increased risk of developing Dupuytren disease (odds ratio, 1.9; 95 percent confidence interval, 1.2 to 2.9). The authors believe this to be the first report of a positive genetic association study in Dupuytren disease using single nucleotide polymorphisms.

Adult↗
PubMed2002

The pulley system of the thumb: anatomic and biomechanical study.

To examine the precise conformation of the annular and oblique pulleys of the thumb flexor sheath, anatomic dissections were undertaken on 14 hands. In all specimens a distinct pulley was found between the A1 and oblique pulleys. This is named the variable annular pulley or Av pulley. There appear to be 3 discrete forms of this pulley designated type I to III. The biomechanical study was done on 8 limbs by using linear strain transduction techniques. The analysis showed that the strain in the oblique pulley was greater in extension than in flexion of the thumb. This statement remains true even after division of either the A1 or Av pulley and after section of both pulleys. The oblique pulley does not prevent bowstringing of the flexor pollicis longus when A1 and Av pulleys have been sectioned. These studies challenge current concepts of both the anatomy and mechanics of the thumb pulley system with implications for clinical procedures such as trigger thumb release and pulley reconstruction.

Aged↗
PubMed2002

Transforming growth factor-12 polymorphism and systemic lupus erythematosus.

OBJECTIVE: To determine whether transforming growth factor-beta2 (TGF-beta2) gene polymorphism is associated with systemic lupus erythematosus (SLE) susceptibility. TGF-beta is a multifunctional family of cytokines important in tissue repair, inflammation and immunoregulation. SLE is thought to be a T cell dependent autoimmune disorder with T cell dysfunction. Due to its known suppressive effects on interleukin 2 dependent T cell growth, TGF-beta2 is considered to be a candidate SLE susceptibility gene. Furthermore, SLE has been linked with a region to which the TGF-beta2 gene has been mapped. METHODS: Association studies were performed in 3 case-control populations, from Spain. Turkey, and UK, using a TGF-beta2 5'-untranslated region (5'-UTR) 4 base pair (bp) insertion polymorphism. Genotyping was performed using fluorescent labeled polymerase chain reaction product sizing. Results. No significant differences were detected in TGF-beta2 5'-UTR polymorphism allele frequencies between SLE patients and matched controls in the 3 populations studied. CONCLUSION: The 4 bp insertion polymorphism within the TGF-beta2 gene does not appear to be associated with SLE. However, this does not rule out the possible involvement of TGF-beta2 in the disease pathogenesis.

Alleles↗