Clinical characterization of patients with leucine-rich repeat kinase 2 genetic variants in Japan.

Variants of leucine-rich repeat kinase 2 (LRRK2) are the most common genetic cause of familial Parkinson's disease (PD). We aimed to investigate the genetic and clinical features of patients with PD and LRRK2 variants in Japan by screening for LRRK2 variants in three exons (31, 41, and 48), which include the following pathogenic mutations: p.R1441C, p.R1441G, p.R1441H, p.G2019S, and p.I2020T. Herein, we obtained data containing LRRK2 variants derived from 1402 patients with PD (653 with sporadic PD and 749 with familial PD). As a result, we successfully detected pathogenic variants (four with p.R1441G, five with p.R1441H, seven with p.G2019S, and seven with p.I2020T) and other rare variants (two with p.V1447M, one with p.V1450I, one with p.T1491delT, and one with p.H2391Q). Two risk variants, p.P1446L and p.G2385R, were found in 10 and 146 patients, respectively. Most of the patients presented the symptoms resembling a common type of PD, such as middle-aged onset, tremor, akinesia, rigidity, and gait disturbance. Dysautonomia, cognitive decline, and psychosis were rarely observed. Each known pathogenic variant had a different founder in our cohort proven by haplotype analysis. The generation study revealed that the LRRK2 variants p.G2019S and p.I2020T were derived 3500 and 1300 years ago, respectively. Our findings present overviews of the prevalence and distribution of LRRK2 variants in Japanese cohorts.

Oxidation of a cysteine-derived nucleophilic reagent by dimethyl sulfoxide in the amino acid derivative reactivity assay.

The amino acid derivative reactivity assay (ADRA), which is an in chemico alternative to the use of animals in testing for skin sensitization potential, offers significant advantages over the direct peptide reactivity assay (DPRA) in that it utilizes nucleophilic reagents that are sensitive enough to be used with test chemical solutions prepared to concentrations of 1 mm, which is one-hundredth that of DPRA. ADRA testing of hydrophobic or other poorly soluble compounds requires that they be dissolved in a solvent consisting of dimethyl sulfoxide (DMSO) and acetonitrile. DMSO is known to promote dimerization by oxidizing thiols, which then form disulfide bonds. We investigated the extent to which DMSO oxidizes the cysteine-derived nucleophilic reagents used in both DPRA and ADRA and found that oxidation of both N-(2-(1-naphthyl)acetyl)-l-cysteine (NAC) and cysteine peptide increases as the concentration of DMSO increases, thereby lowering the concentration of the nucleophilic reagent. We also found that use of a solvent consisting of 5% DMSO in acetonitrile consistently lowered NAC concentrations by about 0.4 µm relative to the use of solvents containing no DMSO. We also tested nine sensitizers and four nonsensitizers having different sensitization potencies to compare NAC depletion with and without 5% DMSO and found that reactivity was about the same with either solvent. Based on the above, we conclude that the use of a solvent containing 5% DMSO has no effect on the accuracy of ADRA test results. We plan to review and propose revisions to OECD Test Guideline 442C based on the above investigation.

Occurrence, fate and environmental risk of linear alkylbenzene sulfonate in the Langat and Selangor River basins, Malaysia.

Five homologs (C10-C14) of linear alkylbenzene sulfonate (LAS) were quantitated in surface water collected in the Langat and Selangor River basins using liquid chromatography-tandem mass spectrometry (LC-MS/MS). A geographic information system (GIS) was used to spatially analyze the occurrence of LAS in both river basins, and the LAS contamination associated with the population was elucidated by spatial analysis at a sub-basin level. The LAS concentrations in the dissolved phase (<0.45 µm) and 4 fractions separated by particle size (<0.1 µm, 0.1-1 µm, 1-11 µm and >11 µm) were analyzed to elucidate the environmental fate of LAS in the study area. The environmental risks of the observed LAS concentration were assessed based on predicted no effect concentration (PNEC) normalized by a quantitative structure-activity relationship model. The LAS contamination mainly occurred from a few populated sub-basins, and it was correlated with the population density and ammonia nitrogen. The dissolved phase was less than 20% in high contamination sites (>1000 µg/L), whereas it was more than 60% in less contaminated sites (<100 µg/L). The environmental fate of LAS in the study area was primarily subject to the adsorption to suspended solids rather than biodegradation because the LAS homologs, particularly in longer alkyl chain lengths, were considerably absorbed to the large size fraction (>11 µm) that settled in a few hours. The observed LAS concentrations exceeded the normalized PNEC at 3 sites, and environmental risk areas and susceptible areas to the LAS contamination were spatially identified based on their catchment areas.

Effects of Seijo-bofu-to, a traditional Japanese herbal medicine containing furanocoumarin derivatives, on the drug-metabolizing enzyme activities in healthy male volunteers.

Seijo-bofu-to, a traditional medicine used to treat acne in Asian countries, contains twelve herbal components, including Angelica dahurica root, a source of furanocoumarin derivatives. In this study, we investigated potential herb-drug interactions of seijo-bofu-to in healthy male volunteers. Thirty-two young, healthy, non-smoking males were assessed for the baseline activity of cytochrome P450 (CYP) 1A2, CYP3A, CYP2D6, N-acetyltransferase 2 and xanthine oxidase according to the urinary metabolic indices of 8-hr urine samples collected after the administration of a 150-mg dose of caffeine and a 30-mg dose of dextromethorphan, and the ratio of urinary excretion of 6ß-hydroxycortisol to cortisol. Thereafter, the volunteers received 3.75 g of seijo-bofu-to twice daily for 7 days and underwent the same tests on post-dose day 7. The geometric mean ratio of the CYP1A2 activity on day 7 to that observed at baseline was 0.66 (95% CI, 0.55-0.79, p = 0.001). The geometric mean phenotypic indices for CYP3A, CYP2D6, N-acetyltransferase 2 and xanthine oxidase on day 7 did not differ from the baseline values. The findings of the present study suggest that seijo-bofu-to may inhibit the activity of CYP1A2, whereas it is unlikely to participate in herb-drug interactions involving medications predominantly metabolized by CYP3A, CYP2D6, N-acetyltransferase 2 or xanthine oxidase.

Pregnane X receptor and hepatocyte nuclear factor 4α polymorphisms are cooperatively associated with carbamazepine autoinduction.

OBJECTIVE: We attempted to clarify the influence of polymorphisms of nuclear receptors on carbamazepine therapy. PARTICIPANTS AND METHODS: The common polymorphisms of nuclear receptors--a tentative pregnane X receptor (PXR)*1B, hepatocyte nuclear factor 4α (HNF4α) rs2071197 (c.115+308G>A), and cytochrome P450 3A5*3 polymorphisms--were genotyped in 168 Japanese patients with epilepsy. The associations of these polymorphisms with the disposition, clinical efficacy, and incidence of adverse effects of carbamazepine treatment were retrospectively investigated in 104 patients treated with carbamazepine alone. The associations with disposition were also assessed in 64 patients treated with carbamazepine and other antiepileptic drugs, which constituted the internal replication group, and in the combined 168 patients. RESULTS: Neither polymorphism alone affected the carbamazepine disposition, but a significant interactive effect of PXR*1B and HNF4α rs2071197 polymorphisms on the concentration-to-dose (C/D) ratios was observed (P=0.027). The C/D ratios among patients with the HNF4α G/G genotype were higher in PXR*1B carriers than in PXR*1B noncarriers, which was confirmed in the internal replication and combined groups. In patients with the HNF4α G/G genotype, the rate of freedom from seizures until 3 months after starting carbamazepine therapy was significantly greater and the time required to reach the dose required for seizure freedom was shorter in PXR*1B carriers than in PXR*1B noncarriers. CONCLUSION: These results suggest that PXR*1B, in combination with HNF4α rs2071197, might be associated with the C/D ratios and the duration to reach the maintenance dose of carbamazepine therapy, thus indicating an influence upon the autoinduction of the carbamazepine metabolism.

A herbal-drug interaction study of keishi-bukuryo-gan, a traditional herbal preparation used for menopausal symptoms, in healthy female volunteers.

OBJECTIVES: Many patients use herbal medicines to relieve menopausal symptoms. Keishi-bukuryo-gan contains five herbal components, and has been used for treating hypermenorrhoea, dysmenorrhoea and menopausal symptoms in Asian countries. In this study, we investigated the potential herb-drug interactions of keishi-bukuryo-gan in healthy female subjects. METHODS: Thirty-one healthy females (20-27 years) were studied to evaluate their baseline activity of cytochrome P450 (CYP) 1A2, CYP2D6, CYP3A, xanthine oxidase (XO) and N-acetyltransferase 2 (NAT2) based on the urinary metabolic indices of an 8-h urine sample collected after a 150-mg dose of caffeine and a 30-mg dose of dextromethorphan, and also the urinary excretion ratio of 6ß-hydroxycortisol to cortisol. Thereafter, the subjects received 3.75g of keishi-bukuryo-gan twice daily for seven days, and underwent the same tests on post-dose day 7. KEY FINDINGS: The geometric mean phenotypic index for CYP1A2 significantly decreased by 16% on day 7 compared with the baseline (P=0.026). Keishi-bukuryo-gan did not alter the indices for CYP2D6, CYP3A, XO and NAT2. CONCLUSIONS: Keishi-bukuryo-gan may inhibit the activity of CYP1A2, which is predominantly involved in oestrogen metabolism. However, TJ-25 is unlikely to participate in herb-drug interactions involving medications predominantly metabolized by CYP2D6, CYP3A, XO and NAT2. K