Identification & characterization of leucine-rich repeat kinase 2 & parkin RBR E3 ubiquitin protein ligase variants in patients with Parkinson's disease.

BACKGROUND & OBJECTIVES: Parkinson's disease (PD) is a motor disorder that affects movement. More than 24 loci and 28 associated genes have been identified to be associated with this disease. The present study accounts for the contribution of two candidates, leucine-rich repeat kinase 2 ( LRRK2) and parkin RBR E3 ubiquitin protein ligase ( PRKN) in the PD patients, and their characterization in silico and in vitro. METHODS: A total of 145 sporadic PD cases and 120 ethnically matched healthy controls were enrolled with their informed consent. Mutation screening was performed by direct DNA sequencing of the targeted exons of LRRK2 and all exons flanking introns of PRKN. The effect of the pathogenic PRKN variants on a drug (MG-132) induced loss of mitochondrial membrane potential (△ΨM) was measured by a fluorescent dye tetramethylrhodamine methyl ester (TMRM). RESULTS: Twelve and 20 genetic variants were identified in LRRK2 and PRKN, respectively. Interestingly, five out of seven exonic LRRK2 variants were synonymous. Further assessment in controls confirmed the rarity of two such p.Y1527 and p.V1615. Among the pathogenic missense variations (as predicted in silico) in PRKN, two were selected (p.R42H and p.A82E) for their functional study in vitro, which revealed the reduced fluorescence intensity of TMRM as compared to wild type, in case of p.R42H but not the other. INTERPRETATION & CONCLUSIONS: About 6.2 per cent of the cases (9/145) in the studied patient cohort were found to carry pathogenic (as predicted in silico) missense variations in PRKN in heterozygous condition but not in case of LRRK2 which was rare. The presence of two rare synonymous variants of LRRK2 (p.Y1527 and p.V1615) may support the phenomenon of codon bias. Functional characterization of selected PRKN variations revealed p.R42H to cause disruption of mitochondrial membrane potential (△ΨM) rendering cells more susceptible to cellular stress.

Steering interest rates amidst large structural surplus liquidity: a tale of three central banks.

This paper focuses on as to how three central banks, viz. the United States Federal Reserve (US Fed), the European Central Bank (ECB) and the Reserve Bank of India (RBI), steered interest rates in the face of large surplus liquidity. This study finds that it is challenging to steer the interest rate in the middle of the corridor when there is large surplus liquidity. However, the floor of the policy corridor (the ECB and the RBI) and the interest rates on excess reserves (the US Fed) prevented overnight interest rates from collapsing. As such, the relationship between interest rates and surplus liquidity was found to be non-linear, i.e. beyond a certain threshold, surplus liquidity had no material additional impact on interest rates.

Prolidase-Associated Trace Elements (Mn, Zn, Co, and Ni) in the Patients with Parkinson's Disease.

Micronutrients and trace elements have been identified to play an important role in the development of Parkinson's disease (PD). In our previous study, we observed that prolidase activity is associated with oxidative stress and progression of PD. In present study, we aimed to study the association of prolidase-associated trace elements, such as Co, Mn, Ni, and Zn in the plasma of patients with PD by inductively coupled plasma spectrometry. Plasma levels of Co, Mn, and Ni were significantly increased, whereas plasma levels of Zn was significantly decreased (all P < 0.05) in the patients with PD than healthy controls. Plasma prolidase activity was not correlated to its associated trace elements in PD. A positive, linear, and significant correlation was observed between age and Co, and Mn, and Ni while negative and non-significant between age and status of Zn in the patients. Co, Mn, and Ni were continually elevated with increase in age as well as duration of disease in the patients with PD, whereas status of Zn was continually decreased. Thus, the study concluded that trace elements Co, Ni, and Mn status were increased and Zn status was decreased in the plasma of patients with PD. It is also concluded that elevated Co, Mn, and Ni has been associated with progression of Parkinson's disease.

Plasma Prolidase Activity and Oxidative Stress in Patients with Parkinson's Disease.

Prolidase deficiency has been related to mental retardation and oxidative stress. The study aimed to observe plasma prolidase activity (PPA), total oxidant status (TOS), total antioxidant status (TAS), and oxidative stress index (OSI) in patients with Parkinson's disease (PD). 240 subjects with PD and 150 healthy volunteers were considered as cases and controls, respectively. PPA, TOS, TAS, and OSI were measured spectrophotometrically. PPA and TAS in cases were more significantly decreased than controls (P < 0.01), while TOS and OSI were significantly increased (P < 0.001). In cases, nonsignificant, positive correlation was observed between PPA and TOS and OSI while significant, negative correlation was observed between PPA and TAS (P = 0.047). PPA in cases was nonsignificantly decreased with increased duration of PD (P = 0.747) while TAS was significantly decreased (P < 0.001) and TOS and OSI were significantly increased (P < 0.001). It was observed that higher age groups had decreased PPA, and TAS and increased TOS and OSI compared to lower age groups in cases. In summary, patients with PD have decreased PPA and increased oxidative stress compared to healthy volunteers. PPA was associated with oxidative stress markers in patients with PD. Decreased PPA and TAS and increased TOS and OSI were associated with progression of disease and higher age.

Novel P-TEN-induced putative kinase 1 (PINK1) variant in Indian Parkinson's disease patient.

Loss-of-function mutation in PINK1 is known for causing autosomal recessive early onset Parkinsonism accounting approximately 6.5% of PD cases. Recently, PINK1 has also been shown to cause Parkinson's disease (PD) in eastern India. Present study is aimed to see its contribution in north-Indian PD patients. A total of 106 PD patients and 60 ethnically matched healthy controls were included in the study. All the patients were screened for mutation in PINK1 by direct DNA sequence analysis of the PCR amplicons covering all exons and exon-intron boundaries. Identified novel variant was reconfirmed by DNA sequencing of 10 randomly selected TA clones containing the variant amplicon. In vitro functional assay of the mutant protein was performed by transfecting COS-7 cell line with wild type and mutant (created by site-directed-mutagenesis) cDNA construct of PINK1 fused to N' terminal GFP followed by western blot analysis. Two potentially pathogenic, one being novel (p.Q267X) and 6 other apparently non-pathogenic variants were identified. Western blot analysis reveals production of truncated PINK1 fusion protein of ∼55kDa in p.Q267X mutant instead of 82/93kDa of wild type PINK1 fusion protein (molecular weight of GFP is ∼27kDa). Our study concludes that PINK1 variants are prevalent for causing Parkinson's disease (PD) in India, as revealed by the occurrence of 1.8% (2/106) in PD patients from north Indian population. The novel homozygous variant of PINK1 (c.799C>T) reported here is the plausible cause for disease manifestation in this patient. Future study, however, would be helpful to understand the functional mechanism how this premature PINK1 protein (p.Q267X) responds to cellular stress leading to the PD pathophysiology.

Role of flupirtine as a preemptive analgesic in patients undergoing laparoscopic cholecystectomy.

BACKGROUND AND AIMS: Postsurgical pain is the leading complaint after laparoscopic cholecystectomy that may delay the postoperative recovery and hence we undertook a prospective randomized trial to analyze the role of flupirtine as a preemptive analgesic for postoperative pain relief in patients undergoing above surgery. MATERIAL AND METHODS: A total of 66 cases were randomly assigned to two groups to receive capsule flupirtine (200 mg) or capsule vitamin B complex administered orally, 2 h before the laparoscopic cholecystectomy surgery. Time to first analgesic requirement, assessment of postoperative pain in terms of visual analog score, and analgesic requirement postoperatively were measured as a primary outcome. RESULTS: Time to first analgesic requirement was significantly prolonged in the flupirtine group as compared with the placebo group. There was significant pain reduction in early postoperative period (up to 4 h), but no changes occurred thereafter. Total analgesic requirement (including rescue analgesia) and side-effects were comparable between the groups except for higher sedation in flupirtine group. CONCLUSIONS: Flupirtine is effective as a preemptive analgesic in providing adequate pain relief during the immediate postoperative period after laparoscopic cholecystectomy surgery. However, continuation of drug therapy postoperatively could possibly delineate its optimal analgesic profile more profoundly.