Raloxifene glucuronidation in liver and intestinal microsomes of humans and monkeys: contribution of UGT1A1, UGT1A8 and UGT1A9.

1. Raloxifene is an antiestrogen that has been marketed for the treatment of osteoporosis, and is metabolized into 6- and 4'-glucuronides by UDP-glucuronosyltransferase (UGT) enzymes. In this study, the in vitro glucuronidation of raloxifene in humans and monkeys was examined using liver and intestinal microsomes and recombinant UGT enzymes (UGT1A1, UGT1A8 and UGT1A9). 2. Although the K(m) and CL(int) values for the 6-glucuronidation of liver and intestinal microsomes were similar between humans and monkeys, and species differences in Vmax values (liver microsomes, humans > monkeys; intestinal microsomes, humans < monkeys) were observed, no significant differences were noted in the K(m) or S50, Vmax and CL(int) or CLmax values for the 4'-glucuronidation of liver and intestinal microsomes between humans and monkeys. 3. The activities of 6-glucuronidation in recombinant UGT enzymes were UGT1A1 > UGT1A8 >UGT1A9 for humans, and UGT1A8 > UGT1A1 > UGT1A9 for monkeys. The activities of 4'-glucuronidation were UGT1A8 > UGT1A1 > UGT1A9 in humans and monkeys. 4. These results demonstrated that the profiles for the hepatic and intestinal glucuronidation of raloxifene by microsomes were moderately different between humans and monkeys.

Target-controlled infusion and population pharmacokinetics of landiolol hydrochloride in gynecologic patients.

PURPOSE: We previously determined the pharmacokinetic (PK) parameters of landiolol in healthy male volunteers. In this study, we evaluated the usefulness of target-controlled infusion (TCI) of landiolol hydrochloride and determined PK parameters of landiolol in gynecologic patients. METHODS: Nine patients who were scheduled to undergo gynecologic surgery were enrolled. After inducing anesthesia, landiolol hydrochloride was administered at the target plasma concentrations of 500 and 1,000 ng/mL for each 30 min. A total of 126 data points of plasma concentration were collected from the patients and used for the population PK analysis. Furthermore, a population PK model was developed using the nonlinear mixed-effect modeling software. RESULTS: The patients had markedly decreased heart rates (HRs) at 2 min after the initiation of landiolol hydrochloride administration; however, their blood pressures did not markedly change from the baseline value. The concentration time course of landiolol was best described by a 2-compartment model with lag time. The estimate of PK parameters were total body clearance (CL) 34.0 mL/min/kg, distribution volume of the central compartment (V 1) 74.9 mL/kg, inter-compartmental clearance (Q) 70.9 mL/min/kg, distribution volume of the peripheral compartment (V 2) 38.9 mL/kg, and lag time (ALAG) 0.634 min. The predictive performance of this model was better than that of the previous model. CONCLUSION: TCI of landiolol hydrochloride is useful for controlling HR, and the PK parameters of landiolol in gynecologic patients were similar to those in healthy male volunteers and best described by a 2-compartment model with lag time.

Risk Factors for Adverse Events of Nanoliposomal Irinotecan Plus 5-Fluorouracil and L-leucovorin.

Background/Aim: The regimen with nanoliposomal irinotecan plus 5-fluorouracil and L-leucovorin (nal-IRI/FL) is used for metastatic pancreatic cancer. A clinical study has indicated that the uridine diphosphate-glucuronosyltransferase (UGT) 1A1 polymorphism is associated with neutropenia during nal-IRI/FL treatment; however, no studies have reported risk factors for the occurrence of adverse events in the clinical setting. This study aimed to explore the risk factors for adverse events of nal-IRI/FL. Patients and Methods: This study included patients with metastatic pancreatic cancer who started nal-IRI/FL treatment. Patient information, including laboratory data before nal-IRI/FL initiation and adverse events during nal-IRI/FL treatment, was retrospectively obtained from medical records. Results: This study consisted of 36 patients, including 16, 16, and 4 with UGT1A1*6 or *28 wild-type (-/-), heterozygous (+/-), and homozygous (+/+), respectively. Patients with UGT1A1*6 or *28 (+/+) exhibited significantly lower nadir counts of white blood cells (p=0.033) and neutrophils (p=0.043). Multiple regression analyses revealed that the decreased white blood cell count was significantly associated with the genotype of UGT1A1*6 or *28 (+/+) (p=0.009), high aspartate aminotransferase (AST) value before the therapy (p=0.019), and pancreatic head cancer (p=0.030). Also, the decreased neutrophil count was significantly related to the genotype of UGT1A1*6 or *28 (+/+) (p=0.017). Conclusion: Patients with UGT1A1*6 or *28 (+/+) should be especially concerned about neutropenia and leukopenia during nal-IRI/FL treatment. Additionally, high AST value and pancreatic head cancer may be risk factors for leukopenia during nal-IRI/FL treatment.

Levoleucovorin as replacement for leucovorin in cancer treatment.

OBJECTIVE: To comprehensively review the literature regarding the efficacy, safety, and costs associated with the use of levoleucovorin in cancer treatment and to assess whether levoleucovorin would be a reasonable alternative to the use of racemic leucovorin. DATA SOURCES: A MEDLINE search was conducted for English-language human studies published between January 1980 and April 2012 using the terms l-LV, levoleucovorin, d,l-LV, leucovorin, folinic acid, folinate, 5-formyltetrahydrofolate, folic acid, folates, methotrexate, 5-fluorouracil, and clinical trials. STUDY SELECTION AND DATA EXTRACTION: Articles pertinent to clinical trials (Phase 1, 2, 3) related to evaluating the efficacy, interchangeability, and safety of levoleucovorin were collected and their contents reviewed. DATA SYNTHESIS: From these pharmacokinetics and clinical studies, information on the use of levoleucovorin as a modulator of fluorouracil as well as when combined with other antitumor agents were scrutinized and extracted for comparison with leucovorin whenever possible. Two randomized Phase 3 clinical studies comparing the efficacy and adverse effect profiles of leucovorin and levoleucovorin demonstrated that levoleucovorin is as effective as leucovorin in terms of response, toxicity, and survival. Six randomized Phase 3 clinical studies demonstrated the safety and efficacy of levoleucovorin as a modulator of fluorouracil in combination with/without other antitumor agents in colorectal cancer patients. Levoleucovorin has been studied in other cancers. These clinical Phase 1/2/3 studies demonstrated efficacy and safety of levoleucovorin in combination chemotherapeutic regimens comprising fluorouracil and other antitumor agents. CONCLUSIONS: The results of the clinical studies suggest that levoleucovorin is efficacious and can be used safely in combination with fluorouracil and other antitumor agents. Levoleucovorin can be used interchangeably with leucovorin for modulating fluorouracil. The current shortage of the supply of leucovorin centered in North America renders levoleucovorin a reasonable alternative in terms of efficacy and toxicity profile, but from the perspective of cost, leucovorin remains the drug of choice.

Favorable survival even with high disease-specific complication rates in lymphangioleiomyomatosis after lung transplantation-long-term follow-up of a Japanese center.

BACKGROUND: Lung transplantation (LT) is a reliable therapeutic option for end-stage pulmonary lymphangioleiomyomatosis (LAM). Long-term outcome of LAM recipients after LT remains unknown. The aim of this study was to describe the outcomes of LT for LAM with a long-term follow-up, comparing those for other diseases in the same period. METHODS: We retrospectively reviewed consecutive 145 LT recipients between 1998 and 2015 at Okayama University Hospital with minimum 3-year follow-up. RESULTS: Twelve LAM recipients including nine sporadic-LAM and three tuberous sclerosis complex -LAM were identified. Nine of 12 underwent bilateral LT including four living-donor lobar LT. There was no significant difference in overall survival between the two groups. (P = 0.15). Chronic lung allograft dysfunction free survival rate in LAM compared with other diseases tended to be better (P = 0.058). However, the rate of requiring hemodialysis was significantly higher in LAM recipients than in the recipients of other diseases (P = 0.047). Notably, 8 of 12 (67%) LAM patients encountered LAM-related complication including chylothorax and pneumothorax, seven (58%) had proliferative diseases consisting of renal angiomyolipoma and recurrent LAM. Nine patients required mTOR inhibitors for LAM-related problems, contributing to improved control of LAM-related problems. While all nine recipients of bilateral LT have still survived, two patients died of diseases in their native lungs and one required re-LT among three recipients of single LT. CONCLUSION: Although the rates of LAM-related complications were unexpectedly high in the long term, LT is a feasible therapeutic option for patients with advanced pulmonary LAM.

Success of Crizotinib Combined with Whole-Brain Radiotherapy for Brain Metastases in a Patient with Anaplastic Lymphoma Kinase Rearrangement-Positive Non-Small-Cell Lung Cancer.

Although crizotinib shows marked antitumor activity in anaplastic lymphoma kinase (ALK) rearrangement-positive non-small-cell lung cancer (NSCLC) patients, all treated patients ultimately develop resistance to this drug. Isolated central nervous system failure without progression at extracranial sites is a common progression pattern in ALK rearrangement-positive NSCLC patients treated with crizotinib. Here, we report the success of crizotinib combined with whole-brain radiotherapy in an ALK rearrangement-positive NSCLC patient who developed leptomeningeal carcinomatosis and progression of multiple brain metastases. Additionally, we focused on the mechanism involved by examining the plasma and cerebrospinal fluid concentrations of crizotinib in the present case.

Improved high-performance liquid chromatographic detection of paclitaxel in patient's plasma using solid-phase extraction, and semi-micro-bore C18 separation and UV detection.

Although a number of analytical methods for taxanes have been published, none of them are sufficiently suitable for use in a medical setting. In this study, we established an improved analytical HPLC/UV detection method using a Sep-Pak C18 cartridge for extraction and a semi-micro-borecolumn for separation. This method employed here reduced chromatographic background signals, and allowed a more sensitive analysis of taxanes in human blood sample. The recovery of taxanes after the solid-phase extraction procedure was over 90%. Chromatographic separation of paclitaxel and docetaxel was achieved within 30 min with no interference peak by a semi-micro-bore column, packed either with C18 (Wakosil 5C18 RS) or pentafluorophenyl (Curosil/Taxol) materials. The method was reproducible with coefficients of variation less than 6%. This analytical procedure was simple and sensitive with lower quantification limit of 3 ng/ml. The improved sensitivity achieved by the popular HPLC/UV apparatus, which is available in hospitals, would vouch safer and more efficient therapy with taxane.

Detection of dexmedetomidine in human breast milk using liquid chromatography-tandem mass spectrometry: Application to a study of drug safety in breastfeeding after Cesarean section.

Several analytical methods for dexmedetomidine (DEX) in human plasma have been published, but quantification of DEX in human breast milk has not been described. In this article, we describe a high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method suitable for quantification of DEX in human breast milk. DEX and an internal standard were extracted in a single liquid-liquid extraction step with diethyl ether from 200µL of human breast milk. HPLC was performed on a TSK-gel ODS-100V column with isocratic elution at a flow rate of 0.3mL/min using a mobile phase of 5mM ammonium formate:0.1% formic acid in acetonitrile (60:40, v/v). Detection was performed using an API4000 mass spectrometer with positive electrospray ionization. The method was validated in the concentration range of 10pg/mL (lower limit of quantification) to 2000pg/mL. The intra- and inter-day accuracy were within ±5.8% and precision was <6.31% based on the coefficient of variation. The recoveries of DEX in human breast milk were 82.4-87.9%. Recovery and matrix effects were consistent and reproducible for human breast milk. The method is robust and was successfully used in a study of drug safety in breastfeeding in patients after administration of DEX.

Tandospirone, a 5-HT1A agonist, ameliorates movement disorder via non-dopaminergic systems in rats with unilateral 6-hydroxydopamine-generated lesions.

Serotonin 1A (5-HT1A) receptors are distributed throughout the brain with their highest concentrations in the frontal cortex, subthalamic nucleus and entopeduncular nucleus as well as the dorsal and median raphe nucleus. There is growing evidence that 5-HT1A receptor agonists have an antidepressant effect in individuals with major depressive disorders. Recent clinical studies suggest that tandospirone, a highly potent and selective 5-HT1A receptor agonist used clinically as an antidepressant in Japan and China, may act as an antiparkinsonian drug. In the present study, we investigated the effect of tandospirone on contralateral rotational behavior in a unilateral hemiparkinsonian rat model produced with 6-hydroxydopamine (6-OHDA). Tandospirone, as well as 8-hydroxy-2-(di-n-propylamino) tetralin (8-OHDPAT), significantly increased contralateral turnings in a dose-dependent manner (0.5-10 mg/kg). Tandospirone also remarkably potentiated the contralateral turning induced by 0.025 mg/kg of apomorphine. Pretreatment with WAY-100635, a 5-HT1A receptor antagonist, almost completely blocked the contralateral turning behavior evoked by tandospirone and 8-OHDPAT, but not that by apomorphine. SCH-23390, a selective dopamine D1 receptor antagonist, did not affect on the tandospirone-induced rotational behavior. These results suggested that tandospirone could act on postsynaptic 5-HT1A receptors and modulate excitatory amino acid pathways in the basal ganglia. Thus, tandospirone could have therapeutic potential for the treatment of Parkinson's disease by modulating neuronal activities of non-dopaminergic pathways.

STAT3 polymorphism rs4796793 may be a predictive factor of tumor response to multiple tyrosine kinase inhibitors in metastatic renal cell carcinoma in Japanese population.

Signal transducer and activator of transcription (STAT) 3 is a key factor in multiple tyrosine kinase inhibitor (mTKI)-induced growth inhibition and apoptosis of renal cell carcinoma (RCC) cells. This study aimed to identify associations between single-nucleotide polymorphisms (SNPs) in the STAT3 gene and tumor response to mTKIs in patients with metastatic RCC (mRCC). Seventy-one patients with clear cell RCC treated with any mTKI were retrospectively genotyped to elucidate a potential association between STAT3 SNPs and overall best response to drugs. Of 50 patients included for analysis, a partial or complete response was observed in 17. A significant association was found between rs4796793 alleles and tumor response [G vs. C, odds ratio (OR) 3.25, 95 % confidence interval (CI) 1.30-8.07]. There were a higher percentage of responders with the C/C genotype at rs4796793 than with the G/C + G/G genotypes (OR 4.46, 95 % CI 1.31-15.28). Time-to-event analysis demonstrated a statistically significant difference between patients with the CC genotype and those with G/C + G/G genotypes in time-to-treatment response, but not in progression-free survival or time-to-treatment failure. The rs4796793 genotype is a novel predictive factor of the response to mTKIs in patients with mRCC. However, prospective translational trials with larger patient cohorts are required to confirm these results.

Association of Single Nucleotide Polymorphisms in STAT3 with Hand-Foot Skin Reactions in Patients with Metastatic Renal Cell Carcinoma Treated with Multiple Tyrosine Kinase Inhibitors: A Retrospective Analysis in Japanese Patients.

BACKGROUND: Signal transducer and activator of transcription (STAT)3 is a reported mediator of molecular-targeted drug-induced keratinocyte toxicity. AIM: Our purpose was to assess the association of single nucleotide polymorphisms (SNPs) in STAT3 with hand-foot skin reactions (HFSR) in patients with metastatic renal cell carcinoma (mRCC) treated with multiple tyrosine kinase inhibitors (mTKIs). PATIENTS AND METHODS: Sixty-five Japanese patients with clear cell renal cell carcinoma who were treated with any mTKI at Kobe University Hospital were retrospectively genotyped to elucidate a potential association between STAT3 polymorphisms and HFSR development. RESULTS: The final analysis included 60 patients. HFSR was observed in 46 patients. The GG, GC, and CC genotypes at rs4796793 were found in 9, 27, and 24 patients, respectively. Three other STAT3 polymorphisms exhibited tight linkage disequilibrium with rs4796793. A significant association was found between the rs4796793 allele and HFSR [G vs. C; odds ratio [OR], 4.33; 95 % confidence interval [CI], 1.80-10.45; P = 0.001]. The GG genotype had the highest OR compared with GC + CC genotypes (OR, 10.75; 95 % CI, 2.38-48.07; P = 0.001). In a time-to-event Kaplan-Meier analysis, a statistically significant difference was observed between the GC + CC and the GG genotypes (P = 0.009). CONCLUSIONS: The rs4796793 genotype appears to be a novel factor for mTKI-induced HFSR in patients with mRCC. Prospective translational trials with larger numbers of patients are required to confirm our results. This research suggests a potential benefit of STAT3 polymorphism screening in patients treated with mTKIs.

[Sex identification from DNA in old teeth].

The sex determination was carried out on 80 fresh and 15 old teeth by amplifying sex chromosome specific sequences with the polymerase chain reaction. The DNA content in the tooth significantly decreases with aging. There was no correlation between days after evulsion and the amounts of DNA extracted from fresh teeth that had been preserved less than 186 days. The sex determination based on fresh teeth was successful using multi locus markers, DYZ-1 and DYZ-3 in combination with DXZ-1. However, amelogenin and pseudoautosomal boundary, both that are single locus markers and specific for both sex chromosomes with different lengths, could not be detected in three samples, of which DNA contents were extremely low. However, the sex determination by amelogenin amplified with fluorescent probes was possible in these three samples. We also determined sexes of 30 old specimens (15 teeth and 15 bones) from 15 human skulls using sex chromosomes locus markers. Prior to molecular sex determination, two forensic specialists determined the sex of the skull morphologically. From the 15 skulls, sex identification using multi locus marker (DYZ-1 or DYZ-3) was possible for 12 of 15 teeth and 7 of 15 bones. The sex was successfully determined from 11 teeth and 9 bones by amplification of the amelogenin locus. However, the coincidence rate of the molecular test with morphological examination was < 20%. In conclusion, sex determination on the fresh tooth would be successful using any sex chromosome marker. However, in cases on samples that have spent considerable years in the ground, pollution and putrefaction, especially, by humicolous, must be considered. Thus, sex determination by DNA testing should be regarded as accurate, when the results from two or more molecular markers are coincident. Hokkaido J Med Sci 80(2), 191-199, 2005

Photostability studies on (±)-tramadol in a liquid formulation.

BACKGROUND: Tramadol ((±)-TRA) is recommended for the treatment of mild to moderate cancer pain by the World Health Organization. An oral liquid formulation of (±)-TRA is preferable for patients with a compromised swallowing function. However, the stability of (±)-TRA in aqueous solution has yet to be determined in a clinical setting. The aim of this study was to evaluate the photostability of (±)-TRA in aqueous solution in a clinical setting. METHODS: We improved high performance liquid chromatography (HPLC) method for the enantiomeric separation of (±)-TRA, and then the (±)-TRA concentration was determined using HPLC method. We investigated the photodegradation of (±)-TRA in an aqueous solution irradiated with ultraviolet (UV) light: UV-A, UV-B, and UV-C. We also evaluated the stability of liquid formulations of (±)-TRA in a clinical setting by keeping (±)-TRA aqueous solution in normal dispensing bottles and in light-shading dispensing bottles under conditions of both sunlight and diffused light in a room. Samples were collected sequentially over time. RESULTS: (±)-TRA in aqueous solution was degraded the most rapidly when irradiated with UV-C, but was not affected by irradiation with UV-A. No significant difference was observed in the photodegradation behavior of (+)-TRA and (-)-TRA with UV-A, UV-B, and UV-C irradiation. The residual percentages of (±)-TRA were 94.6-104.3% after 14 days in the presence of either sunlight or diffused light in a room, with or without protection from light. CONCLUSIONS: These results demonstrated the stability of (±)-TRA in aqueous solution to both sunlight and diffused light in a room. Therefore, liquid formulations of TRA are preserved at room temperature for up to 2 weeks, with or without protection from light. Our results provide additional treatment options with tramadol for pain control.

Correlation of plasma crizotinib trough concentration with adverse events in patients with anaplastic lymphoma kinase positive non-small-cell lung cancer.

BACKGROUND: Crizotinib, an ATP-competitive receptor tyrosine kinase inhibitor of both anaplastic lymphoma kinase (ALK) and the hepatocyte growth factor receptor, commonly causes several adverse events (AEs). The clinical utility of measuring the plasma concentration of crizotinib in patients with non-small-cell lung cancer (NSCLC) has not been fully elucidated. The aim of this study was to evaluate the variability in the crizotinib trough concentration and its relationship with the occurrence of AEs in NSCLC patients. FINDINGS: Plasma samples were collected from 9 ALK fusion gene-positive NSCLC Japanese patients at day 14 after the first administration of crizotinib. We assessed crizotinib-induced AEs on days 7, 14, 21, and 28. The crizotinib trough concentration on day 14 ranged from 243.5 to 847.8 ng/mL, and all of the patients achieved stable disease based on assessment of the tumor response on day 28. The cumulative number of AEs on day 28 in the higher trough concentration group was approximately 3-fold greater than that in the lower trough concentration group. AEs of grade 3 or 4 were observed only in patients in the higher trough concentration group. CONCLUSIONS: The occurrence of several AEs may correlate with the increase in the crizotinib trough concentration. Monitoring of the crizotinib trough concentration could predict the risk of development of several AEs and provide guidance for determining the optimal dose of crizotinib.

Refractory cachexia is associated with increased plasma concentrations of fentanyl in cancer patients.

BACKGROUND: An appropriate plasma concentration of fentanyl is the key to achieving good pain control in cancer patients. Cachexia, a multifactorial syndrome, is known to affect drug-metabolizing enzymes. However, the fentanyl concentrations in the blood of patients with cachexia have not been analyzed. The aim of this study was to evaluate the influence of cancer cachexia on dose-adjusted plasma fentanyl concentrations in cancer patients. METHODS: Blood was collected from 21 Japanese cancer patients treated with a 24-hour trans-dermal fentanyl patch during the steady state of fentanyl plasma concentration. Plasma fentanyl concentrations were analyzed using liquid chromatography with tandem mass spectrometry (LC-MS/MS), and the levels were adjusted with the dose of fentanyl. Laboratory data were collected, and the cachexia stage was determined, based on study by Fearon et al. Multiple regression analysis was performed to identify the factors that affected fentanyl plasma concentrations. RESULTS: Eight patients were classified as precachexia, nine as cachexia, and four as refractory cachexia, and the median dose-adjusted fentanyl concentrations (ng/mL per mg/kg/day) were 27.5, 34.4, and 44.5, respectively. The dose-adjusted fentanyl concentration in patients with refractory cachexia was higher than that in patients with precachexia (Kruskal-Wallis test and post hoc Mann-Whitney U-test, P<0.01). The factors that were found to possibly affect the dose-adjusted concentration of fentanyl included aspartate aminotransferase, C-reactive protein, and estimated glomerular filtration rate, when analyzed as six independent variables (multiple regression analysis, P<0.05). CONCLUSION: The dose-adjusted plasma concentrations of fentanyl increased with progression of cancer cachexia. Such an increase is associated with a multifactorial and systemic syndrome in cancer cachexia patients, including lower albumin, higher C-reactive protein, and impaired kidney function. In patients with cancer cachexia, we suggest that evaluation of cancer cachexia might help pain management when using a transdermal fentanyl patch in palliative care.

Alternate-day Treatment with Crizotinib for Drug-induced Esophagitis and Liver Damage in a Patient with EML4-ALK Fusion Gene-positive Lung Adenocarcinoma.

A 44-year-old woman who was diagnosed with anaplastic lymphoma kinase-positive lung adenocarcinoma developed brain metastases, multiple spinal metastases and meningeal dissemination. Crizotinib was administered after the failure of first-line chemotherapy. Esophagitis and liver damage were induced by the twice-daily administration of crizotinib at 250 mg and 200 mg, respectively. The alternate-day administration of crizotinib (250 mg, twice daily) was able to control disease progression without any adverse effects for several months. We evaluated the relationship between the serum concentration of crizotinib and the development of esophagitis and liver damage. The alternate-day administration of crizotinib is one of the strategies for managing the severe toxicity of crizotinib.

Target-controlled infusion and population pharmacokinetics of landiolol hydrochloride in patients with peripheral arterial disease.

PURPOSE: We previously determined the pharmacokinetic (PK) parameters of landiolol in healthy male volunteers and gynecological patients. In this study, we determined the PK parameters of landiolol in patients with peripheral arterial disease. METHODS: Eight patients scheduled to undergo peripheral arterial surgery were enrolled in the study. After inducing anesthesia, landiolol hydrochloride was administered at target plasma concentrations of 500 and 1,000 ng/mL for 30 minutes each. A total of 112 data points of plasma concentration were collected from the patients and used for the population PK analysis. A population PK model was developed using a nonlinear mixed-effect modeling software program (NONMEM). RESULTS: The patients had markedly decreased heart rates at 2 minutes after initiation of landiolol hydrochloride administration; however, systolic blood pressures were lower than the baseline values at only five time points. The concentration time course of landiolol was best described by a two-compartment model with lag time. The estimates of PK parameters were as follows: total body clearance, 30.7 mL/min/kg; distribution volume of the central compartment, 65.0 mL/kg; intercompartmental clearance, 48.3 mL/min/kg; distribution volume of the peripheral compartment, 54.4 mL/kg; and lag time, 0.633 minutes. The predictive performance of this model was better than that of the previous model. CONCLUSION: The PK parameters of landiolol were best described by a two-compartment model with lag time. Distribution volume of the central compartment and total body clearance of landiolol in patients with peripheral arterial disease were approximately 64% and 84% of those in healthy volunteers, respectively.

N-methylation underlying Parkinson's disease.

The discovery of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) leads to the hypothesis that Parkinson's disease (PD) is maybe initiated or precipitated by environmental or endogenous toxins by the mechanism similar to that of MPTP in genetically-predisposed individuals. Endogenous analogs of MPTP, such as beta-carbolines (betaCs) and tetrahydroisoquinolines, have been proposed as possible causative candidates causing PD and are bioactivated into potential neurotoxins by N-methylation enzyme(s). These N-methylated betaCs and tetrahydroisoquinoline have been higher cerebrospinal levels in parkinsonian patients than age-matched controls. Thus, there is a hypotheses to influence the pathogenesis of PD, that is, the excess enzyme activity to activate neurotoxins, such as N-methyltransferase, might be higher in PDs. Indeed, simple betaCs, via N-methylation steps, induced bradykinesia with the decreased dopamine contents in the striatum and midbrain in C57/BL mice. In younger (65 years old) PD patients, the excretion amount of N(1)-methyl-nicotinamaide was significantly higher than that in younger controls. The protein amount of nicotinamide N-methyltransferase (NNMT) was also significantly higher in younger PD patients than that in younger controls. These findings described here would indicate that the excess N-methylation ability for azaheterocyclic amines, such as betaCs, before the onset had been implicated in PD pathogenesis. On the other hand, the contribution of aberrant cytochrome P450 or aldehyde oxidase activity acting on the pyridine ring, that could act as detoxification routes of endogenous neurotoxins, would be small in the etiology of PD.

Genotyping of cytochrome p450 isoform genes is useful for forensic identification of cadaver.

Tailor-made medical treatment based on the polymorphism of genes encoding drug-metabolizing enzymes has been advocated and is being tried on an experimental basis at numerous centers. If DNA polymorphism analysis becomes routine in tailor-made medical treatment, it will be very useful in forensic identification. In this study, we determined the genotype frequencies of five p450 (CYP) isoform genes, CYP1A2, CYP2D6, CYP2E1, CYP2C9 and CYP2C19 in 196 Japanese individuals to evaluate their forensic usefulness. These genes encode the most important enzymes among the CYP superfamily that metabolize clinically used drug. The frequency of each allele agreed well with those reported previously and their genotype frequencies did not deviate from those expected from Hardy-Weinberg equilibrium. CYP2C subfamilies such as CYP2C9 and CYP2C19 on chromosome 10 showed high sequence homology, as high as over 95% in the regions flanking polymorphic sites. Although 3240 genotype combinations of these five CYP isoform genes are theoretically possible, 101 combinations were detected in this study. The genotype frequencies of these five isoform genes excluded their linkage. The following two genotype combinations showed the highest frequency of 0.036: CYP1A2*1A/*1A, CYP2D6*1/*10, CYP2E1*1/*1, CYP2C9*1/*1 and CYP2C19*1/*1 and CYP1A2*1A/*1C, CYP2D6*1/*10, CYP2E1*1/*1, CYP2C9*1/*1 and CYP2C19*1/*1. Thus, genotyping of CYP isoform genes should be useful in forensic identification.