Mn-SOD 47 CC genotype in combination with high tea consumption may prevent complications in Tunisian type-2 diabetes.

Reactive oxygen species metabolizing enzymes may play an important role in the prevention of type-2 diabetes (T2D) complications. We analyzed the association between Cu/Zn-SOD +35 A/C, Mn-SOD T47C, and CAT -21 A/T gene polymorphisms and complications, in combination with tea consumption in Tunisian T2D. A sample of 366 T2D subjects was enrolled in this study. All participants were asked about tea consumption and frequency. Anthropometric, clinical, and routine biochemical characteristics were obtained from subjects' updated medical records. Malondialdehyde, as an early marker of lipid peroxidation, was measured in plasma samples. Urinary polyphenol derivatives (UPDs), as a marker of polyphenols intake, were assessed by the Folin-Ciocalteu assay. SODs and CAT genotypes were determined by conventional restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) methods. From all subjects, the results showed that in high tea consumers (>3 cups/day), the frequency of the Mn-SOD 47 CC genotype was significantly higher in T2D without complications compared with T2D with complications (P = 0.03; OR = 0.284; 95%CI = 0.086-0.939). However, no significant associations were observed with Cu/Zn-SOD +35 A/C or CAT -21 A/T genes polymorphisms. Additionally, the evaluation of UPDs showed that individuals carrying the Mn-SOD 47 CC genotype and consuming more than three cups of tea per day present significantly higher UPDs (P = 0.038). In conclusion, the Mn-SOD 47 C variant in combination with high tea consumption may provide protection against complications in T2D.

Bias toward a 1:1 ratio in primer-introduced restriction analysis PCR: mechanism and minimization.

Primer-introduced restriction analysis is widely used in molecular genetics. However, several studies have reported inconsistent data regarding sequencing, mainly among heterozygous samples. This discrepancy may be related to the bias towards a 1:1 ratio typically observed in heterozygous digestion products. In this study, we investigated the mechanism and minimization of this observed bias. Three mismatched polymerase chain reaction (PCR) models were analyzed by testing different PCR conditions and reaction mixtures. For EPHX1 gene rs1051740 single-nucleotide polymorphism PCR, DNA concentration, denaturation and elongation time, annealing temperature, and cycle number significantly influenced product ratios. For SERPINA1 gene PIMmalton deletion (ΔPhe52) and CHRNA3 gene rs1051730 single-nucleotide polymorphism PCRs, significant bias fluctuations were observed only for the annealing temperature and cycle number conditions. The relevance of these results to the amplification efficiency parameter is discussed. Rather than reducing the observed bias, our data provide evidence of a counterbalance for preferential amplification, depending on cycle number, annealing temperature, and amplification efficiency alteration. Our results are relevant for application to primer-introduced restriction analysis PCR assays.