Tacrolimus-Induced Apoptosis is Mediated by Endoplasmic Reticulum-derived Calcium-dependent Caspases-3,-12 in Jurkat Cells

Apoptotic signal pathways are delivered to caspase-3, caspase-9, or both in different cells via the death receptor pathway, mitochondrial pathway, or by the endoplasmic reticulum (ER) pathway through initiators of caspase-3, -8, -9, or -12. Tacrolimus (Tac)-induced apoptosis was characterized by nuclear fragmentation and caspase-3 activation. We examined the effect of tacrolimus on ER-derived calcium and caspase-3,-12-mediated apoptosis on Jurkat human T lymphocyte. Tac decreased the viability of Jurkat cells in a dose-dependent manner. Tac also increased continuously intracellular concentration of calcium from 24 hours to 72 hours. We did not find intracellular calcium changes on the treatment of calcium ionorpore (A23187) regardless of 1 nmol/L Tac concentration level. However, calcium adenosine triphosphatase inhibitor (thapsigargin) increased intracellular calcium accumulation and co-treating 1 nmol/L Tac further induced intracellular calcium accumulation. Interestingly, we found that 1 nmol/L Tac treatment induced activation of caspase-12 protease as well as the catalytic activity of caspase-3 but not catalytic activation of caspase-6, -8, and -9 proteases in Jurkat cells. These data advance our understanding of Tac-induced apoptosis is ER-derived calcium and caspases-3,-12- mediated apoptosis in human Jurkat cell line.

Expression efficiency of NAT2 haplotypes in a Korean population

Since NAT2 single-nucleotide polymorphisms (SNPs) are responsible for the efficacy of arylamines and hydrazine drugs, defining the effects of these SNPs in various ethnicities is an important factor in the development of personalized medicine. In the present study, we examined the expression efficiency of NAT2 using promoter haplotypes identified in a Korean population. To construct NAT2 promoter haplotypes, seven NAT2 promoter SNPs (rs4646241, rs4646242, rs4646243, rs4646267, rs4345600, rs4271002 and rs4646246) were genotyped in a total of 192 Korean subjects. A luciferase assay was performed using the three commonest haplotypes to evaluate enzyme expression level of NAT2 promoter haplotypes. The most common haplotype (TACGAGG) showed the lowest enzyme expression level (0.72 ± 0.06 relative light units (RLU)/[β-galactosidase]). The second (CGTAAGA) and third (TATAACA) commonest haplotypes showed intermediate and the highest enzyme expression level (0.99 ± 0.05 and 1.45 ± 0.11 RLU/[β-galactosidase]), respectively. Haplotype comparison among populations showed that Asian populations had a high proportion of the haplotype for lowest enzyme expression. Haplotype frequencies of Caucasian and African ethnicities were markedly different from those of Korean ethnicity. Results from the present study should contribute to the expansion of our current understanding of the pharmacogenetics field.

Comparison of genetic variations of the SLCO1B1, SLCO1B3, and SLCO2B1 genes among five ethnic groups

Organic anion-transporting polypeptide (OATP; gene symbol, SLCO) transporters are generally involved in the uptake of multiple drugs and their metabolites at most epithelial barriers. The pattern of single-nucleotide polymorphisms (SNPs) in these transporters may be determinants of interindividual variability in drug disposition and response. The objective of this study was to define the distribution of SNPs of three SLCO genes, SLCO1B1, SLCO1B3, and SLCO2B1, in a Korean population and other ethnic groups. The study was screened using the Illumina GoldenGate assay for genomic DNA from 450 interethnic subjects, including 11 pharmacogenetic core variants and 76 HapMap tagging SNPs. The genotype distribution of the Korean population was similar to East Asian populations, but significantly different from African American and European American cohorts. These interethnic differences will be useful information for prospective studies, including genetic association and pharmacogenetic studies of drug metabolism by SLCO families.

Exposure-outcome analysis in depressed patients treated with paroxetine using population pharmacokinetics

Purpose

This study investigated population pharmacokinetics of paroxetine, and then performed an integrated analysis of exposure and clinical outcome using population pharmacokinetic parameter estimates in depressed patients treated with paroxetine.

Patients and methods

A total of 271 therapeutic drug monitoring (TDM) data were retrospectively collected from 127 psychiatric outpatients. A population nonlinear mixed-effects modeling approach was used to describe serum concentrations of paroxetine. For 83 patients with major depressive disorder, the treatment response rate and the incidence of adverse drug reaction (ADR) were characterized by logistic regression using daily dose or area under the concentration–time curve (AUC) estimated from the final model as a potential exposure predictor.

Results

One compartment model was developed. The apparent clearance of paroxetine was affected by age as well as daily dose administered at steady-state. Overall treatment response rate was 72%, and the incidence of ADR was 30%. The logistic regression showed that exposure predictors were not associated with treatment response or ADR in the range of dose commonly used in routine practice. However, the incidence of ADR increased with the increase of daily dose or AUC for the patients with multiple concentrations.

Conclusion

In depressed patients treated with paroxetine, TDM may be of limited value for individualization of treatment.

Tobacco smoking-response genes in blood and buccal cells

Tobacco smoking is a well-known cause of various diseases, however, its toxic mechanisms for diseases are not completely understood, yet. Therefore, we performed biological monitoring to find tobacco smoking-responsive mechanisms including oxidative stress in Korean men (N=36). Whole genome microarray analyses were performed with peripheral blood from smokers and age-matched nonsmokers. We also performed qRT-PCR to confirm the microarray results and compared the gene expression of blood to those of buccal cells. To assess the effects of tobacco smoking on oxidative stress, we analyzed urinary levels of malondialdehyde (MDA), a lipid peroxidation marker, and performed PCR-based arrays on reactive oxygen species (ROS)-related genes. As results, 34 genes were differently expressed in blood between smokers and nonsmokers (ps<0.01 and >1.5-fold change). Particularly, the genes involved in immune responsive pathways, e.g., the Fcγ-receptor mediated phagocytosis and the leukocyte transendothelial migration pathways, were differentially expressed between smokers and nonsmokers. Among the above genes, the ACTG1, involved in the maintenance of actin cytoskeleton, cell migration and cancer metastasis, was highly expressed by smoking in both blood and buccal cells. Concerning oxidative stress, smokers showed high levels of urinary MDA and down-regulation of expressions of antioxidant related genes including TPO, MPO, GPX2, PTGR1, and NUDT1 as compared to nonsmokers (ps<0.05). In conclusion, these results suggest that systemically altered immune response and oxidative stress can be tobacco-responsive mechanisms for the related diseases. Based on consistent results in blood and buccal cells, expression of the ACTG1 can be a tobacco smoking-responsive biomarker.

Screening for 392 polymorphisms in 141 pharmacogenes

Pharmacogenomics is the study of the association between inter-individual genetic differences and drug responses. Researches in pharmacogenomics have been performed in compliance with the use of several genotyping technologies. In this study, a total of 392 single-nucleotide polymorphisms (SNPs) located in 141 pharmacogenes, including 21 phase I, 13 phase II, 18 transporter and 5 modifier genes, were selected and genotyped in 150 subjects using the GoldenGate assay or the SNaPshot technique. These variants were in Hardy-Weinberg equilibrium (HWE) (P>0.05), except for 22 SNPs. Genotyping of the 392 SNPs revealed that the minor allele frequencies of 47 SNPs were <0.05, 105 SNPs were monomorphic and 22 variants were not in HWE. Also, based on previous studies, we predicted the association between the polymorphisms of certain pharmacogenes, such as cytochrome P450 2D6, cytochrome P450 2C9, vitamin K epoxide reductase complex, subunit 1, cytochrome P450 2C19, human leukocyte antigen, class I, B and thiopurine S-methyltransferase, and drug efficacy. In conclusion, our study demonstrated the allele distribution of SNPs in 141 pharmacogenes as determined by high-throughput screening. Our results may be helpful in developing personalized medicines by using pharmacogene polymorphisms.

Comprehensive variant screening of the UGT gene family

PURPOSE

UGT1A1, UGT2B7, and UGT2B15 are well-known pharmacogenes that belong to the uridine diphosphate glucuronyltransferase gene family. For personalized drug treatment, it is important to study differences in the frequency of core markers across various ethnic groups. Accordingly, we screened single nucleotide polymorphisms (SNPs) of these three genes and analyzed differences in their frequency among five ethnic groups, as well as attempted to predict the function of novel SNPs.

MATERIALS AND METHODS

We directly sequenced 288 subjects consisting of 96 Korean, 48 Japanese, 48 Han Chinese, 48 African American, and 48 European American subjects. Subsequently, we analyzed genetic variability, linkage disequilibrium (LD) structures and ethnic differences for each gene. We also conducted in silico analysis to predict the function of novel SNPs.

RESULTS

A total of 87 SNPs were detected, with seven pharmacogenetic core SNPs and 31 novel SNPs. We observed that the frequencies of UGT1A1 *6 (rs4148323), UGT1A1 *60 (rs4124874), UGT1A1 *93 (rs10929302), UGT2B7 *2 (rs7439366), a part of UGT2B7 *3 (rs12233719), and UGT2B15 *2 (rs1902023) were different between Asian and other ethnic groups. Additional in silico analysis results showed that two novel promoter SNPs of UGT1A1 -690G>A and -689A>C were found to potentially change transcription factor binding sites. Moreover, 673G>A (UGT2B7), 2552T>C, and 23269C>T (both SNPs from UGT2B15) changed amino acid properties, which could cause structural deformation.

CONCLUSION

Findings from the present study would be valuable for further studies on pharmacogenetic studies of personalized medicine and drug response.

Screening of Genetic Polymorphisms of CYP3A4 and CYP3A5 Genes

Given the CYP3A4 and CYP3A5's impact on the efficacy of drugs, the genetic backgrounds of individuals and populations are regarded as an important factor to be considered in the prescription of personalized medicine. However, genetic studies with Korean population are relatively scarce compared to those with other populations. In this study, we aimed to identify CYP3A4/5 polymorphisms and compare the genotype distributions among five ethnicities. To identify CYP3A4/5 SNPs, we first performed direct sequencing with 288 DNA samples which consisted of 96 Koreans, 48 European-Americans, 48 African-Americans, 48 Han Chinese, and 48 Japanese. The direct sequencing identified 15 novel SNPs, as well as 42 known polymorphisms. We defined the genotype distributions, and compared the allele frequencies among five ethnicities. The results showed that minor allele frequencies of Korean population were similar with those of the Japanese and Han Chinese populations, whereas there were distinct differences from European-Americans or African-Americans. Among the pharmacogenetic markers, frequencies of CYP3A4*1B (rs2740574) and CYP3A5*3C (rs776742) in Asian groups were different from those in other populations. In addition, minor allele frequency of CYP3A4*18 (rs28371759) was the highest in Korean population. Additional in silico analysis predicted that two novel non-synonymous SNPs in CYP3A5 (+27256C>T, P389S and +31546T>G, I488S) could alter protein structure. The frequency distributions of the identified polymorphisms in the present study may contribute to the expansion of pharmacogenetic knowledge.

Screening of dihydropyrimidine dehydrogenase genetic variants by direct sequencing in different ethnic groups

Dihydropyrimidine dehydrogenase (DPYD) is an enzyme that regulates the rate-limiting step in pyrimidine metabolism, especially catabolism of fluorouracil, a chemotherapeutic agent for cancer. In order to determine the genetic distribution of DPYD, we directly sequenced 288 subjects from five ethnic groups (96 Koreans, 48 Japanese, 48 Han Chinese, 48 African Americans, and 48 European Americans). As a result, 56 polymorphisms were observed, including 6 core polymorphisms and 18 novel polymorphisms. Allele frequencies were nearly the same across the Asian populations, Korean, Han Chinese and Japanese, whereas several SNPs showed different genetic distributions between Asians and other ethnic populations (African American and European American). Additional in silico analysis was performed to predict the function of novel SNPs. One nonsynonymous SNP (+199381A > G, Asn151Asp) was predicted to change its polarity of amino acid (Asn, neutral to Asp, negative). These findings would be valuable for further research, including pharmacogenetic and drug responses studies.

Functional characterization of allelic variants of polymorphic human cytochrome P450 2A6 (CYP2A6*5, *7, *8, *18, *19, and *35)

Cytochrome P450 2A6 (CYP2A6) catalyzes important metabolic reactions of many xenobiotic compounds, including coumarin, nicotine, cotinine, and clinical drugs. Genetic polymorphisms of CYP2A6 can influence its metabolic activities. This study analyzed the functional activities of six CYP2A6 allelic variants (CYP2A6*5, *7, *8, *18, *19, and *35) containing nonsynonymous single-nucleotide polymorphisms. Recombinant variant enzymes of CYP2A6*7, *8, *18, *19, and *35 were successfully expressed in Escherichia coli and purified. However, a P450 holoenzyme spectrum was not detected for the CYP2A6*5 allelic variant (G479V). Structural analysis shows that the G479V mutation may alter the interaction between the A helix and the F-G helices. Enzyme kinetic analyses indicated that the effects of mutations in CYP2A6 allelic variants on drug metabolism are dependent on the substrates. In the case of coumarin 7-hydroxylation, CYP2A6*8 and *35 displayed increased K(m) values whereas CYP2A6*18 and *19 showed decreased k(cat) values, which resulted in lower catalytic efficiencies (k(cat)/K(m)). In the case of nicotine 5-oxidation, the CYP2A6*19 variant exhibited an increased K(m) value, whereas CYP2A6*18 and *35 showed much greater decreases in k(cat) values. These results suggest that individuals carrying these allelic variants are likely to have different metabolisms for different CYP2A6 substrates. Functional characterization of these allelic variants of CYP2A6 can help determine the importance of CYP2A6 polymorphisms in the metabolism of many clinical drugs.

Nuclear magnetic resonance-based metabolomics for prediction of gastric damage induced by indomethacin in rats

Non-steroidal anti-inflammatory drugs (NSAIDs) have side effects including gastric erosions, ulceration and bleeding. In this study, pattern recognition analysis of the (1)H-nuclear magnetic resonance (NMR) spectra of urine was performed to develop surrogate biomarkers related to the gastrointestinal (GI) damage induced by indomethacin in rats. Urine was collected for 5 h after oral administration of indomethacin (25 mg kg(-1)) or co-administration with cimetidine (100 mg kg(-1)), which protects against GI damage. The (1)H-NMR urine spectra were divided into spectral bins (0.04 ppm) for global profiling, and 36 endogenous metabolites were assigned for targeted profiling. The level of gastric damage in each animal was also determined. Indomethacin caused severe gastric damage; however, indomethacin administered with cimetidine did not. Simultaneously, the patterns of changes in their endogenous metabolites were different. Multivariate data analyses were carried out to recognize the spectral pattern of endogenous metabolites related to indomethacin using partial least square-discrimination analysis. In targeted profiling, a few endogenous metabolites, 2-oxoglutarate, acetate, taurine and hippurate, were selected as putative biomarkers for the gastric damage induced by indomethacin. These metabolites changed depending on the degree of GI damage, although the same dose of indomethacin (10 mg kg(-1)) was administered to rats. The results of global and targeted profiling suggest that the gastric damage induced by NSAIDs can be screened in the preclinical stage of drug development using a NMR based metabolomics approach.

Signal detection of methylphenidate by comparing a spontaneous reporting database with a claims database

Data mining is critical for signal detection in pharmacovigilance systems. In this study, we compared signals between spontaneous reporting data and health insurance claims data for a socially issued drug, methylphenidate. We implemented data-mining tools for signal detection in both databases: Reporting Odds Ratios (ROR), Proportional Reporting Ratios (PRR), Chi-squared test, and Information Component (IC), in addition to a Relative Risk (RR) tool in the claims database. The claims database generated 15, 15, 36, 1, and 1 adverse drug reactions (ADRs) by ROR, PRR, chi-square, IC, and RR, respectively. The World Health Organization (WHO) spontaneous database generated 91, 91, 137, and 96 ADRs by ROR, PRR, chi-square, and IC, respectively. We found seven potential matching associations from the claims and WHO databases, but only one of them was present in the Korean spontaneous reporting database. In Korea, spontaneous reporting is still underreported and there is a small amount of data for Koreans. Signal comparison between the claims and WHO databases can provide additional regulatory insight.

Expression of CYP2A6, CYP2D6 and CYP4A11 Polymorphisms in COS7 Mammalian Cell Line

The cytochrome P450 (P450, CYP) are the superfamily of heme-containing monooxygenase enzymes, found throughout all nature including mammals, plants, and microorganisms. Mammalian P450 enzymes are involved in oxidative metabolism of a wide range of endo- and exogenous chemicals. Especially P450s involved in drug metabolisms are important for drug efficacy and polymorphisms of P450s in individuals reflect differences of drug responses between people. To study the functional differences of CYP2A6, CYP2D6, and CYP4A11 variants, we cloned the four CYP2A6, three CYP2D6, and three CYP4A11 variants, which were found in Korean populations, in mammalian expression vector pcDNA by PCR and examined their expressions in COS-7 mammalian cells using immunoblots using P450 specific polyclonal antibodies. Three of four CYP2A6, two of three CYP4A11, and two of three CYP2D6 variants showed expressions in COS-7 cells but the relative levels of expressions are remarkably different in those of each variants. Our findings may help to study and explain the differences between functions of CYP variants and drug responses in Korean populations.

Lack of association between ACE and bradykinin B2 receptor gene polymorphisms and ACE inhibitor-induced coughing in hypertensive Koreans

BACKGROUND & OBJECTIVE

Angiotensin converting enzyme (ACE) inhibitors are used widely in therapy for hypertension, congestive heart failure and myocardial infarction. However, coughing, one of their major adverse effects limits their use. It is documented that Asians are more liable to coughing than Europeans. The aim of this study was to investigate genetic polymorphism involved in ACE inhibitor-induced coughing.

METHODS

We monitored hypertensive subjects (n = 110) treated with ACE inhibitors, and tested for any associations between ACE inhibitor-induced coughing and polymorphisms in the genes for ACE and the bradykinin B2 receptor, which are suspected to be related to coughing.

RESULTS & DISCUSSION

We found no significant differences between the groups with coughing and without coughing in the frequency of ACE I/D (Insertion/Deletion) polymorphisms. One single nucleotide polymorphism was discovered in the promoter (-58T/C) and, one in intron-exon junction upsteam of exon 2 (-59C/A), of the bradykinin B2 receptor gene. However, no significant correlation was found between those genotypes or allele distributions and ACE inhibitor-induced coughing.

CONCLUSION

We found no significant links between polymorphisms of the ACE gene or bradykinin B2 receptor gene with ACE inhibitor-induced coughing in hypertensive Koreans. But, the topic remains controversial and requires more study.

Metabolomics approach to risk assessment: methoxyclor exposure in rats

The primary objective of this study was to develop exposure biomarkers that "correlate with the endocrine-disrupting effects induced by methoxyclor (MTC), an organochlorine pesticide, using" urinary (1)H nuclear magnetic resonance (NMR) spectral data. Exposure biomarkers play an important role in risk assessment. MTC is an environmental endocrine disruptor with estrogenic, anti-estrogenic, and anti-androgenic properties. A new approach of proton nuclear magnetic resonance ((1)H NMR) urinalysis using pattern recognition was proposed for exposure biomarkers of MTC in female rats. The endocrine disruptor was expected to induce estrogenic effects in a dose dependent manner which, was confirmed by the uterotrophic assay. MTC [50, 100, or 200 m g/kg/d, orally (p.o.) or subcutaneously (s.c.)] was administered to ovariectomized female Sprague-Dawley (SD) rats for 3 d consecutively and urine was collected every 24 h. The animals were sacrificed 24 h after the last dose. All animals treated orally with MTC showed a significant increase in uterine and vaginal weight at all doses. However, in the s.c. route, only a high dose of 200 mg MTC/kg induced a significant increase in uterine and vaginal weight. (1)H NMR spectroscopy revealed evident separate clustering between pre- and post-treatment groups using global metabolic profiling through principal component analysis (PCA) and partial least square (PLS) discrimination analysis (DA) after different exposure routes. With targeted profiling, the endogenous metabolites of acetate, alanine, benzoate, lactate, and glycine were selected as putative exposure biomarkers for MTC. Data suggest that the proposed putative exposure biomarkers may be useful in a risk assessment of the endocrine-disrupting effects produced by MTC.

Determination of the active metabolites of sibutramine in rat serum using column-switching HPLC

A simple and direct analysis using column-switching HPLC method was developed and validated for the quantification of active metabolites of sibutramine, N-mono-desmethyl metabolite (metabolite 1, M1) and N-di-desmethyl metabolite (metabolite 2, M2) in the serum of rats administered sibutramine HCl (5.0 mg/kg, p.o.). Rat serum was directly injected onto the precolumn without sample prepreparation step following dilution with mobile phase A, i. e., methanol-ACN-20 mM ammonium phosphate buffer (pH 6.0 with phosphoric acid) (8.3:4.5:87.2 by volume). After the endogenous serum components were eluted to waste, the system was switched and the analytes were eluted to the trap column. Active metabolites M1 and M2 were then back-flushed to the analytical column for separation with mobile phase B, i. e., methanol-ACN-20 mM ammonium phosphate buffer (pH 6.0 with phosphoric acid) (35.8:19.2:45 by volume) and detected at 223 nm. The calibration curves of active metabolites M1 and M2 were linear in the range of 0.1-1.0 microg/mL and 0.15-1.8 microg/mL. This method was fully validated and shown to be specific, accurate (10.4-10.7% error), and precise (1.97-8.79% CV). This simple and rapid analytical method using column-switching appears to be useful for the pharmacokinetic study of active metabolites (M1 and M2) of sibutramine.

Aroclor 1254-induced cytotoxicity in catecholaminergic CATH.a cells related to the inhibition of NO production

The neuronal nitric oxide synthase (nNOS) specific inhibitor, 7-nitroindazole (7-NI), and the nitric oxide (NO) donor (S-nitroso-N-acetylpenicillarnine, SNAP) were used to study the role of NO in polychlorinated biphenyl (PCB: Aroclor 1254)-induced cytotoxicity in the immortalized dopaminergic cell line (CATH.a cells), derived from the central nervous system of mice. Treatment of the dopaminergic cells with various concentrations of Aroclor 1254 (0.5-10 microg/ml), a commercial PCB mixture, showed significant cytotoxicity as evaluated by lactate dehydrogenase (LDH) release and assessment of cell viability, depending on the concentration used. We also observed that Aroclor 1254 treatment reduced the level of nNOS expression. Furthermore, the cytotoxicity of Aroclor 1254 was augmented by 10 microM of 7-NI, which alone did not produce cytotoxicity, while it was protected by treatment with SNAP. Depending on the concentrations of Aroclor 1254 used, intracellular dopamine and dihydroxyphenylacetic acid (DOPAC) concentrations were significantly decreased. Therefore, these results suggest that PCBs have the potential for dopaminergic neurotoxicity, which may be related with the PCBs-mediated alteration of NO production originating from nNOS at least in part.

Emergent patterns of feedback strategies in performing a closed motor skill

This sturdy identified self-chosen patterns of feedback usage and how they influenced accuracy and consistency in performing a closed motor skill. Learners completed 100 practice trials with 25 opportunities to receive knowledge of results (KR), the timing of which was self-chosen, followed by 25 no KR retention trials. The study identified two patterns of self-chosen KR, namely, a faded frequency pattern and a reversed faded frequency pattern. Analyses of variance indicated a significant trial block effect for accuracy in acquisition and no significant main effects or interactions associated with self-chosen patterns of KR. Quantification of regularity of KR patterns yielded correlations indicating that less regularity was associated with greater accuracy in performing the task. These results were congruent with previous research on self chosen feedback.

Modulation of NMDA receptor subunit mRNA in butorphanol-tolerant and -withdrawing rats

The NMDA receptor has been implicated in opioid tolerance and withdrawal. The effects of continuous infusion of butorphanol on the modulation of NMDA receptor subunit NR1, NR2A, NR2B, and NR2C gene expression were investigated by using in situ hybridization technique. Continuous intracerebroventricular (i.c.v.) infusion with butorphanol (26 nmol/microl/h) resulted in significant modulations in the NRI, NR2A, and NR2B mRNA levels. The level of NR1 mRNA was significantly decreased in the cerebral cortex, thalamus, and CA1 area of hippocampus in butorphanol tolerant and withdrawal (7 h after stopping the infusion) rats. The NR2A mRNA was significantly decreased in the CA1 and CA3 of hippocampus in tolerant rats and increased in the cerebral cortex and dentate gyrus in butorphanol withdrawal rats. NR2B subunit mRNA was decreased in the cerebral cortex, caudate putamen, thalamus, CA3 of hippocampus in butorphanol withdrawal rats. No changes of NR1, NR2A, NR2C subunit mRNA in the cerebellar granule cell layer were observed in either butorphanol tolerant or withdrawal rats. Using quantitative ligand autoradiography, the binding of NMDA receptor ligand [3H]MK-801 was increased significantly in all brain regions except in the thalamus and hippocampus, at the 7 hr after stopping the butorphanol infusion. These results suggest that region-specific changes of NMDA receptor subunit mRNA (NR1 and NR2) as well as NMDA receptor binding ([3H]MK-801) are involved in the development of tolerance to and withdrawal from butorphanol.

Protective effects of bergenin, the major constituent of Mallotus japonicus, on D-galactosamine-intoxicated rat hepatocytes

This study was designed to investigate the effects of bergenin against D-galactosamine-induced injury in primary cultured rat hepatocytes. Bergenin (100 microM) decreased the release of glutamic pyruvic transaminase and sorbitol dehydrogenase by 62 and 50%, respectively, into hepatocyte medium incubated for 14 h with 1.5 mM galactosamine. Decreased RNA synthesis by 1.5 mM galactosamine was recovered 2.5 times compared with that of control hepatocytes at 100 microM bergenin. Therefore, the present results suggest that bergenin show hepatoprotective effects against galactosamine-intoxicated rat hepatocytes by inhibiting the release of glutamic pyruvic transaminase and sorbitol dehydrogenase as well as by increasing RNA synthesis.

Effect of low back posture on the morphology of the spinal canal

OBJECTIVE

To define the possible mechanism of posture-dependent symptoms of spinal stenosis by measuring the effect of low back posture on morphologic changes of the intervertebral discs and spinal canal in healthy young people.

DESIGN

Twenty healthy young volunteers underwent magnetic resonance imaging while supine with their spine in neutral, flexed, extended, and right and left rotational positions. The axial MR images at the middle of the intervertebral discs of L3-4 and L4-5 were analyzed to measure the difference in the size and shape of the intervertebral discs and spinal canal in each posture.

RESULTS

Extension or rotation decreased the sagittal diameters and cross-sectional areas of the dural sac and spinal canal and increased the thickness of the ligamentum flavum, whereas flexion had the opposite effects. The gap between the convex posterior disc margin and the anterior margin of the facet joint on each side, represented as the subarticular sagittal diameter, increased with flexion and decreased with extension or rotation. The direction of rotation did not result in asymmetry of the subarticular sagittal diameter, but right rotation caused thickening of the right ligamentum flavum, and vice versa. The shape and dimensions of the disc did not change significantly according to the positions of the low back.

CONCLUSIONS

With extension or rotation, the thickness of the ligamentum flavum increased and the posterior margin of the intervertebral disc was approximated to the facet joint without any change in shape and size of the disc. These phenomena result in a decrease in the size of the spinal canal and dural sac in extension or rotation postures in young healthy people without disc degeneration, and may explain the posture-dependent symptom of spinal stenosis.

Anti-inflammatory effects of fangchinoline and tetrandrine

Fangchinoline and tetrandrine are the major alkaloids from Stephania tetrandrae S. Moore which has been used traditionally for the treatment of inflammatory diseases in oriental countries including Korea. Both fangchinoline and tetrandrine showed anti-inflammatory effects on mouse ear edema induced by croton oil. In addition, the effects of fangchinoline and tetrandrine on cyclooxygenase, murine interleukin-5 (mIL-5) and human interleukin-6 (hIL-6) were examined in vitro to investigate the anti-inflammatory action mechanisms. One hundred micromolar of fangchinoline showed 35% of inhibition on cyclooxygenase, but the same concentration of tetrandrine did not show any inhibition. On the other hand, 12.5 microM of tetrandrine exhibited 95% of inhibition on mIL-5 activity, while fangchinoline did not show any effects. However, 4 microM of fangchinoline and 6 microM of tetrandrine showed 63 and 86% of inhibitions on hIL-6 activity, respectively. These results suggest that biochemical mechanisms of fangchinoline and tetrandrine on anti-inflammation are significantly different even though they are similar in chemical structure.

Antihepatotoxic activity of bergenin, the major constituent of Mallotus japonicus, on carbon tetrachloride-intoxicated hepatocytes

To determine the antihepatotoxic activity of bergenin from Mallotus japonicus, carbon tetrachloride (CCl4)-induced cytotoxicity in primary cultured rat hepatocytes has been adopted as an assay system. Bergenin significantly reduced the activities of glutamic pyruvic transaminase and sorbitol dehydrogenase released from the CCl4-intoxicated hepatocytes. The antihepatotoxicity of bergenin was also evidenced by elevating the activities of glutathione S-transferase and glutathione reductase, and content of glutathione in the CCl4-intoxicated hepatocytes. From these results, it is assumed that bergenin exerted antihepatotoxicity against CCl4-induced cytotoxicity through glutathione-mediated detoxification as well as free radical suppressing activity.

Suloctidil-induced hepatotoxicity

Suloctidil is a new drug that is currently being evaluated in many clinical trials for use in dementia and thrombotic disorders. Hepatotoxicity has to date been reported exclusively in the European literature, and the few available histologic descriptions have been reported in the French language. We report a case of suloctidil-induced hepatotoxicity documented by serum liver biochemical tests and liver biopsy. Histologic features included focal necrosis of hepatocytes, mild hyperplasia of Kupffer cells, and other features suggestive of mild acute hepatitis.

Substance data bases and right to know laws: application to occupational epidemiology

The Illinois Right to Know (RTK) law included requirements for substance lists to be submitted by companies to the Illinois Department of Labor (IDOL). This provided an opportunity to test the feasibility of identifying workplaces utilizing common chemicals for future epidemiologic investigations. A sample of IDOL files (n = 115) was obtained, and relevant data elements were coded. A second sample of substance names within these files (n = 1,015) was selected, and searches in three standard references were conducted to identify chemical descriptions. Equal proportions of employers and manufacturer/suppliers were in general compliance with RTK law reporting requirements (58%). Forty-five percent of substances sampled from employers (chemical users) and 71% of substances sampled from manufacturer/suppliers (chemical producers and distributors) could be identified. The ability to identify substances reported using chemical names was approximately equal across companies (90%), while the ability to identify substances with nonchemical names was greater in manufacturer (59%) than in employer (32%) files. This study suggests that the ability to identify potential occupationally exposed groups using this resource may be greater among manufacturers than among employers. Recognition of substances used in the workplace could be improved if companies were required to report chemical names.