Visual, rapid, and cost-effective BK virus detection system for renal transplanted patients using gold nanoparticle coupled loop-mediated isothermal amplification (nanoLAMP).

A substantial percentage of kidney transplant recipients show transplant failure due to BK virus-induced nephropathy. This can be clinically controlled by the rapid and timely detection of BK virus infection in immune-compromised patients. We report a rapid (two hours from sample collection, processing, and detection), cost-effective (< 2$), highly sensitive and BKV-specific nanoLAMP (loop-mediated isothermal amplification) diagnostic methodology using novel primers and gold nanoparticles complex-based visual detection. The standardized nanoLAMP showed an analytical sensitivity of 25 copies/µl and did not cross-react with closely related JC and SV40 viruses. This nanoLAMP showed diagnostic sensitivity and specificity as 91% and 96%, respectively, taking 50 BK virus-negative (confirmed by qPCR from the plasma of healthy donors) and 57 positive BKV patient samples (confirmed by clinical parameters and qPCR assay). This simple two-step, low-cost, and quick (1-2 h/test) detection would be advantageous over the currently used diagnostic methodology. It may change the paradigm for polyomavirus infection-based failure of renal transplant.

Plasminogen activator inhibitor-1 promoter sequence variations in idiopathic osteonecrosis of head of femur.

Background & objectives: Primary or idiopathic osteonecrosis of femur head (ONFH) is the second most commonly observed cause among Indian patients suffering from ischemic ONFH. Although a number of genetic polymorphisms have been associated with idiopathic ONFH pathogenesis in Korean and Chinese populations, there are no studies in the Indian population. This is an exploratory study designed to implicate in promoter sequence polymorphisms of a critical fibrinolytic system regulator, plasminogen activator inhibitor-1 (PAI-1) gene, in cases of idiopathic osteonecrosis. Promoter sequence variations can affect expression levels of PAI-1 gene and may disrupt the coagulation/fibrinolytic equilibrium, which may finally culminate into osteonecrosis. Hence, the aim of the study was to investigate the role of single-nucleotide polymorphisms (SNPs) in the promoter region of PAI-1 gene and osteonecrosis development. Methods: Two SNPs of the PAI-1 gene (rs2227631, -844 G/A; rs1799889, -675 4G/5G) were genotyped in 25 patients diagnosed with idiopathic ONFH and 25 control subjects, using direct sequencing. Subsequently, association analyses were performed for the genotyped SNPs. Results: Both the rs2227631 and rs1799889 genotype and allele frequencies of PAI-1 gene showed an insignificant association with osteonecrosis risk (P=0.717, 0.149). Haplotype frequencies of rs2227631 and rs1799889 were also calculated in patients having idiopathic ONFH and controls. Although the distribution of haplotype GA-4G 4G was found to be the highest among the cases, it was not significantly different when compared with the controls. Interpretation & conclusions: Our findings demonstrate that the minor alleles of promoter region sequences of the PAI-1 gene do not contribute to an increase in ONFH predisposition. However, this is a preliminary study and its findings should be considered as suggestive for studies to be done in a larger sample size.