Galvanostatic and potentiostatic fluorination of 2-indanone, 1-indanone and 1,3-indandione in Et3N · 4HF medium. Adsorption effects on yield and product selectivity

Selective electrochemical fluorination (SEF) of 1-indanone, 2-indanone and 1,3-indandione were carried out in Et₃N · 4HF ionic liquid. Cyclic voltammetric measurements indicated that the ionic liquid undergoes oxidation below 2 V on platinum electrode while the background limit is extended up to 2.3 V on glassy carbon electrode. Well defined voltammetric peaks were observed for all the three compounds on glassy carbon electrode. Significant absorption effects were also noticed. Preparative electrolysis indicated lower selectivity for all the three compounds under galvanostatic conditions when compared to potentiostatic conditions. Both under galvanostatic and potentiostatic conditions, 2-indanone, which exhibits weak adsorption, gave 1-fluoro-2-indanone with high selectivity. 1-Indanone exhibits higher anodic oxidation potential around 2 V. 1,3-Indandione exhibited strong intermediate or product adsorption during voltammetric measurements. The yield and selectivity were much lower for these two compounds under galvanostatic conditions. Quite interestingly in both these cases, the selectivity close to 70% for the monofluorinated compound could be achieved under potentiostatic conditions by passing up to 6 F/mole of electric charge. Prevention of formation of over oxidation products under potentiostatic conditions may be the main cause for this improvement as suggested by chronoamperometric measurements.     

Efficacy of diffusion tensor anisotropy indices and tractography in assessing the extent of severity of spinal cord injury: an in vitro analytical study in calf spinal cords

Background contextSignal intensity changes observed in magnetic resonance imaging (MRI) do not reveal the actual severity of axonal damage incurred in spinal cord injuries. Diffusion tensor imaging (DTI) is an imaging technique with a potential to track individual nerve fiber tracts.PurposeWe explored the use of DTI in quantifying the extent of spinal cord injury and differentiated areas of injured spinal cord from regions with intact fiber tracts in a cadaveric animal model.Study designRadiological study on cadaveric calf spinal cord specimens.MethodsDiffusion tensor imaging was performed in six freshly acquired spinal cord specimens of Indian calves (Bos primigenius indicus). An axial single-shot echo planar parallel diffusion-weighted imaging sequence was done with a 1.5-tesla MRI. Through fixed seed points, tracking of white matter tracts was done. Diffusion tensor imaging anisotropy indices, fractional anisotropy (FA), apparent diffusion coefficient (ADC), relative anisotropy (RA), volume ratio (VR), and eigenvector (E1) values were acquired at each region of interest. Various injuries were then inflicted in the spinal cord, and DTI was repeated. The tractography images and DTI anisotropy indices were compared with those of the uninjured specimens.ResultsThe mean FA, ADC, VR, RA, and E1 values of normal spinal cord were 0.849±0.025, 0.52±0.073 μm²/ms, 0.250±0.04 μm²/ms, 0.889±0.027, and 1.178±0.22 μm²/ms, respectively. The average FA and RA of injured spinal cord regions were significantly decreased being 0.651±0.024 and 0.704±0.041, respectively, at the sites of mild compression. The mean VR values showed significant increase being 0.502±0.027 and 0.628±0.031 μm²/ms at the sites of mild and severe compression. Fractional anisotrophy, RA, and VR values showed a progressive alteration as the severity of compression increased. In contrast, the ADC and E1 values did not show significant changes at the sites of pathology. Tractography of injured spinal cord revealed that the white matter was disrupted at the injury site but preserved on the intact regions clearly differentiating regions of partial and complete transection and varying degrees of compression from normal spinal cord.ConclusionThe study shows that DTI tractography is useful for structural imaging of the spinal cord. Fractional anisotrophy, RA, and VR parameters were found to be more sensitive than ADC and E1 values in assessing the severity of compression.     

Correction of endothelial dysfunction after selective homocysteine lowering gene therapy reduces arterial thrombogenicity but has no effect on atherogenesis

Hyperhomocysteinemia is an independent risk factor for ischemic cardiovascular diseases, but its causal role in atherothrombosis remains controversial. Proatherogenic and/or prothrombotic effects may underlie the potential causal relation between hyperhomocysteinemia and cardiovascular events. Here, the effects of selective lowering of plasma homocysteine, plasma cholesterol, or both on endothelial function and on atherogenesis in male hyperlipidemic and hyperhomocysteinemic C57BL/6 low-density lipoprotein receptor (LDLr)^−/−/cystathionine-β-synthase (CBS)^+/−-deficient mice were investigated. Second, we evaluated whether selective homocysteine lowering has anti-thrombotic effects in a model of arterial thrombosis. A hyperhomocysteinemic and atherogenic diet was started at the age of 12 weeks. Three weeks later, gene transfer was performed with E1E3E4-deleted adenoviral vectors for hepatocyte-restricted overexpression of CBS (AdCBS) or of the LDLr (AdLDLr), or with the control vector Adnull. In a fourth group, AdCBS and AdLDLr were co-administered. Selective homocysteine lowering but not selective cholesterol lowering restored endothelial function at 6 weeks after gene transfer. Intimal area in the aortic root and in the brachiocephalic artery at 13 weeks was more than 100-fold (p < 0.001) smaller in AdLDLr and AdCBS/AdLDLr mice than in control mice and AdCBS mice. No differences in intimal area were observed between control mice and AdCBS mice. In a model of carotid artery thrombosis, the average time to first occlusion and to stable occlusion were 1.9-fold (p < 0.01) and 2.1-fold longer (p < 0.01), respectively, in AdCBS-treated mice than in control mice. Taken together, these data show that correction of endothelial dysfunction following selective homocysteine lowering has anti-thrombotic but no anti-atherogenic effects.     

Quantification of cinacalcet by LC-MS/MS using liquid-liquid extraction from 50 μL of plasma

A simple and economical high-performance liquid chromatography-positive ion electrospray tandem mass spectrometry method was developed and validated for the quantification of cinacalcet in plasma. Following liquid-liquid extraction, the analyte was separated using an isocratic mobile phase on a reversed-phase column and analyzed by MS/MS in the multiple reaction monitoring mode using the respective [M+H]⁺ ions, m/z 358-155 for cinacalcet and m/z 310-148 for the internal standard. The assay exhibited a linear dynamic range of 0.1-200 ng/mL for cinacalcet in plasma. Acceptable precision (<10%) and accuracy (100 ± 5%) were obtained for concentrations over the standard curve range. A run time of 3.5 min for each sample made it possible to analyze more than 250 samples per day. The method was successfully applied to quantify cinacalcet concentrations in a preclinical pharmacokinetic study after a single oral administration of cinacalcet at 10 mg/kg to rats. Following oral administration the maximum mean concentration in plasma (C_max; 160 ± 56 ng/mL) was achieved at 1.0 h (T_max), area under the curve (AUC) and half-life (t_1/2) were 949 ± 257 ng h/mL and 3.58 ± 0.4 h, respectively.     

A study on clinical diagnosis of tuberculosis in free ranging and captive wild animals of India

Background:Tuberculosis (TB) is a disease of paramount importance at the wildlife-livestock-human interface. Aims:To study the occurrence and Mycobacterium (M) species involved in the TB of free-ranging and captive wild animals in various Indian states. Methods: A total of 396 clinical samples from 207 different wild animal species from various Indian national parks, zoological gardens, etc., were analyzed by lateral flow assay (LFA), Ziehl-Neelsen (ZN) staining, and PCR. Clinical samples include blood (n=156), faecal swabs (n=103), serum (n=73), and nasal swabs or trunk wash fluids (n=64). Results:Clinical signs of TB were absent in 202 animals, although 21 wild animals were seropositive for pathogenic Mycobacterium antigens by LFA. Clinical signs like progressive weight loss, and respiratory distress were exhibited by 4 sloth bears (Melursus ursinus) and an elephant (Elephas maximus), which were also found positive for LFA, PCR, and ZN staining. ZN staining showed positivity for acid-fast bacilli (AFB) in 9 (8.74%) faecal and 9 (14.06%) nasal swabs or trunk wash fluids of sloth bears (7 samples) and elephants (2 samples). M. tuberculosis was detected in 7 sloth bears and 2 elephants, whereas M. bovis was found in a spotted deer (Axis axis) by species-specific PCR. Conclusion:The circulation of TB organisms in wild animals warrants a strict surveillance programme to identify the carrier status of these animals so that effective TB control strategies can be formulated.Key Words: Elephant, Lateral flow assay, Mycobacterium, Sloth bear     

Quantitative in vitro phenotyping and prediction of drug interaction potential of CYP2B6 substrates as victims

1.?Determination of f_{m, CYP} for a compound is critical to assess the potential risk of a drug candidate as a victim of DDI. Several compounds are identified as CYP2B6 substrates, but the f_{m, CYP2B6} values are not determined quantitatively.

2.?Two methods of reaction phenotyping, the chemical inhibition method and metabolism in rCYP enzymes, were used to determine the relative contributions of the enzymes. Chemical inhibition method was also conducted in the presence of BSA (0.5% w/v).

3.?The results confirm with the earlier studies concerning the identity of the CYP2B6 enzyme. The f_{m, CYP2B6} values for artemisinin, bupropion, clopidogrel, ketamine, selegiline, sertraline and ticlopidine were 0.24, 0.28, 0.15, 0.45, 0.46, 0.42 and 0.54, respectively, in HLM determined by chemical inhibition method. The f_{m, CYP2B6} values for artemisinin, bupropion, clopidogrel, ketamine, selegiline, sertraline and ticlopidine were 0.46, 0.17, 0.15, 0.60, 0.51, 0.66 and 0.77, respectively, in HLM determined by chemical inhibition method in the presence of BSA (0.5% w/v).

4.?Bupropion metabolism is majorly mediated by CYP2C19 (0.41) with a minor contribution from CYP2B6 (0.16) in the presence of BSA. Ticlopidine is a time-dependent inhibitor of both CYP2B6 and CYP2C19 that can inhibit the bupropion metabolism by 50–60%.