Investigation of the enantioselectivity and enantiomeric elution order of some piperidine-2,6-dione drugs on chiralcel OD column

The enantioselectivity and enantiomeric separation of five racemic piperidine-2,6-dione compounds, on the cellulose tris(3,5-dimethylphenyl carbamate) chiral stationary phase Chiralcel OD-CSP were investigated under the same chromatographic conditions. This class of drugs includes glutethimide, aminoglutethimide, cyclohexylaminoglutethimide, pyridoglutethimide, and phenglutarimide. The results revealed that chiral recognition and the binding sites of these drugs on the Chiralcel OD column are similar, regardless of the absolute configuration of the individual enantiomers. A possible chiral recognition mechanism(s) for this class of drugs and the CSP is presented. © 1994 Wiley-Liss, Inc.     

Multilocus loss of DNA methylation in individuals with mutations in the histone H3 Lysine 4 Demethylase KDM5C

Background

A number of neurodevelopmental syndromes are caused by mutations in genes encoding proteins that normally function in epigenetic regulation. Identification of epigenetic alterations occurring in these disorders could shed light on molecular pathways relevant to neurodevelopment.

Results

Using a genome-wide approach, we identified genes with significant loss of DNA methylation in blood of males with intellectual disability and mutations in the X-linked KDM5C gene, encoding a histone H3 lysine 4 demethylase, in comparison to age/sex matched controls. Loss of DNA methylation in such individuals is consistent with known interactions between DNA methylation and H3 lysine 4 methylation. Further, loss of DNA methylation at the promoters of the three top candidate genes FBXL5, SCMH1, CACYBP was not observed in more than 900 population controls. We also found that DNA methylation at these three genes in blood correlated with dosage of KDM5C and its Y-linked homologue KDM5D. In addition, parallel sex-specific DNA methylation profiles in brain samples from control males and females were observed at FBXL5 and CACYBP.

Conclusions

We have, for the first time, identified epigenetic alterations in patient samples carrying a mutation in a gene involved in the regulation of histone modifications. These data support the concept that DNA methylation and H3 lysine 4 methylation are functionally interdependent. The data provide new insights into the molecular pathogenesis of intellectual disability. Further, our data suggest that some DNA methylation marks identified in blood can serve as biomarkers of epigenetic status in the brain.     

An Optimized Immunohistochemistry Technique Improves NMO-IgG Detection: Study Comparison with Cell-Based Assays

Cell-based assays (CBA) have increased the sensitivity of the neuromyelitis optica (NMO)-IgG/aquaporin-4-antibody detection compared to classical tissue-based indirect assays. We describe the sensitivity of an optimized immunohistochemistry (IHC-o) to detect NMO-IgG/aquaporin-4-antibody in comparison with that of two CBA: an in-house (CBA-ih) and a commercial (CBA-c) assay (Euroimmun, Germany). Coded serum from 103 patients with definite NMO and 122 inflammatory controls were studied by IHC-o, CBA-ih, and CBA-c. IHC-o used the same protocol described to detect antibodies against cell surface antigens. CBA-ih used live cells transfected with the aquaporin-4-M23-isoform. The sensitivity of the IHC-o was 74.8% (95% confidence interval [CI] 65-83) and was similar to that of the CBA-ih 75.7% (95% CI 66-84) and the CBA-c 73.8% (95% CI 64-82). The specificity of the three assays was 100% (95% CI 97-100). Interassay concordance was high, 100 of 103 samples were coincident in all techniques. The optimized immunohistochemistry proves to be as sensitive and specific as the cell-based assays. This assay extends the available tools for NMO-IgG/aquaporin-4-antibody detection.     

Synthesis of aldehydo-sugar derivatives of pyrazoloquinoline as inhibitors of herpes simplex virus type 1 replication

Synthesis of a novel series of structurally related pyrazoloquinoline nucleosides is described. All the newly synthesized compounds were examined for their in vitro antiviral activity against herpes simplex type-1 as shown by two different bioassays, namely; crystal violet staining or the MTS tetrazolium dye measurement. The acute toxicity (LD50) values of the biologically active compounds were determined.     

New amperometric biosensors based on diamond paste for the assay of L- and D-pipecolic acids in serum samples

Monocrystalline natural diamond, L-amino acid oxidase (L-AAOD), D-amino acid oxidase (D-AAOD), and paraffin oil were used for the design of the modified diamond paste. The technique used for the direct voltammetric assay was differential pulse voltammetry (DPV) with applied potential pulse amplitude of 25 mV vs. Ag/AgCl. Using the new amperometric biosensors L-pipecolic acid (L-PA) and D-pipecolic acid (D-PA) were determined reliably from serum samples at 700 and 200 mV vs. Ag/AgCl, respectively, with low limits of detection.     

Optimization of the chiral separation of some 2-arylpropionic acids on an avidin column by modeling a combined response

The enantiomeric separation of some nonsteroidal antiinflammatory drugs was investigated on an avidin column. An experimental design approach (central composite design) was used to evaluate the effects of three method parameters (pH, concentration of organic modifier, and buffer concentration) on the analysis time and the resolution, as well as to model these responses. This revealed that the organic modifier concentration and sometimes the pH are significant parameters to control because of their influence on both analysis time and resolution. Furthermore, the central composite design results were combined in a multicriteria decision-making approach in order to obtain a set of optimal experimental conditions leading to the most desirable compromise between resolution and analysis time.     

Recent applications of stereoselective chromatography

Some recent applications of stereoselective chromatography in the fields of clinical pharmacy, drug analysis, food, and natural products are reviewed. The review is documented with up-to-date literature, which will assist further expansion of research in these areas.     

Effect of acidity on the enantiomeric resolution of thyroxine and tocainide by HPLC on a (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid column

Enantiomeric resolution of thyroxine and tocainide was achieved on a (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid column. The mobile phases were methanol/water (4:1, v/v) and methanol/water containing 5 mM sulfuric acid (4:1, v/v) for tocainide and thyroxine respectively. The flow rate was 0.5 ml/min. The effect of the acidity on the chiral resolution of these drugs was studied. Detection was at 220 nm for both drugs. The values of alpha and Rs were 2.08-3.11 and 1.00-2.60, respectively, for thyroxine while the values of alpha and Rs were 1.13-1.26 and 0.10-1.30, respectively, for tocainide.     

Determination of urinary and serum beta-glucuronidase and alkaline phosphatase in various renal disease and kidney rejection transplanted patients

Beta-glucuronidase (beta-Glu) and alkaline phosphatase (ALP) were evaluated in serum and urine in 50 subjects classified into five equal groups. Group I was control healthy subjects, while groups II, III, IV, and V were patients with nephritic syndrome, pyelonephritis, kidney rejection, and end-stage renal disease, respectively. Urinary beta-Glu was significantly elevated in all four groups; while serum enzyme showed no change. On the other hand, serum ALP showed a significant elevation in all abnormal groups. Accordingly, urinary beta-Glu and serum ALP could be used as diagnostic markers for various renal diseases.     

FT-IR spectrophotometric analysis of coenzyme Q10 (CoQ10) and its pharmaceutical formulations

A Fourier transform infrared (FT-IR) spectrometric method was developed for the rapid, direct measurement of coenzyme Q10 (CoQ10) in different pharmaceutical products. Conventional KBr spectra were compared for the best determination of active substance in drug preparations. Lambert-Beer's law and two chemometric approaches, partial least squares (PLS) and principal component regression (PCR+) methods, were used in data processing.