In vivo and in vitro characterization of CYP2E1 activity in Japanese and Caucasians

Chlorzoxazone's disposition after oral administration was determined in 20 young healthy Caucasian men and a similar group of Japanese men. The drug's plasma concentrations were significantly higher and its rate of elimination slower in Japanese compared to Caucasian men. Accordingly, chlorzoxazone's oral clearance was smaller (40%) in Japanese men and a similar difference (30%) was still apparent after normalizing for body weight (3.74 +/- 1.23 versus 5.05 +/- 1.41 ml.min-1.kg-1, P < .05). This slower elimination was associated with a reduced (fractional) clearance by 6-hydroxylation (2.34 +/- 1.04 ml.min-1.kg-1 versus 3.23 +/- 1.10, P < .05). Because such metabolism is mediated by cytochrome P4502E1 (CYP2E1), these findings suggest a lower level of the enzyme's catalytic activity in Japanese men. This was confirmed by in vitro studies with microsomes prepared from livers of individuals representative of the two racial groups. CYP2E1 levels were lower (61% P < .002) and CYP2E1-mediated chlorzoxazone 6-hydroxylase (22%, P < .001) and aniline 4-hydroylase (35%, P < .0001) activities were reduced in Japanese preparations compared to those from Caucasians. No relationships were found between measures of CYP2E1 activity, both in vivo and in vitro, and genomic polymorphisms in the CYP2E1 gene identified by Rsal/Pstl and Dral restriction fragment length polymorphisms. Collectively, these data show an interracial difference in CYP2E1 activity. Because this enzyme is importantly involved in the activation of environmental procarcinogens, such a difference may account, in part, for the lower rate of some cancers, e.g., lung cancer, in Japanese compared to Caucasians men.

Determination of absolute configuration and biological activity of new immunosuppressants, mycestericins D, E, F and G

Mycestericins D, E, F and G were isolated from the culture broth of Mycelia sterilia ATCC 20349 as potent immunosuppressants. Mycestericins F and G were identical with dihydromycestericins D and E, respectively. Their absolute configurations were determined by use of the modified MOSHER'S method and by comparison of the CD spectra of their benzoate derivatives with those of synthetic analogs. Mycestericins D, E, F and G suppressed the proliferation of lymphocytes in the mouse allogeneic mixed lymphocyte reaction.

Steady-state plasma concentrations of imipramine and desipramine in relation to S-mephenytoin 4'-hydroxylation status in Japanese depressive patients

The steady-state plasma concentrations of imipramine and desipramine were measured after a more than 2-week treatment with 0.39 to 1.39 mg/kg/day of imipramine hydrochloride in 28 Japanese patients with major depression who had been phenotyped simultaneously with mephenytoin (for CYP2C19-related status) and with metoprolol (for CYP2D6-related status) before initiating the antidepressant therapy. Patients consisted of five poor metabolizers (PMs) of CYP2C19 with an extensive metabolizer (EM) phenotype of CYP2D6, whereas the remainder were EMs for both of the phenotypes. The mean respective concentrations (corrected by mg/kg) of imipramine and the sum of imipramine plus desipramine were 2.4 and 1.8 times greater in the CYP2C19-related PM than in the EM group, and these two variables correlated with the log10 urinary excretion of 4'-hydroxymephenytoin (rs = -0.73 and -0.64, both p < 0.01, respectively), but not with the metabolic ratio (MR) of metoprolol/alpha-hydroxymetoprolol. The mean N-demethylation index (MR of desipramine/imipramine) was significantly (p < 0.01) less in the PM than in the EM group. This index correlated with the 4'-hydroxylation of S-mephenytoin (rs = -0.51, p < 0.01), but not with the alpha-hydroxylation of metoprolol, implying that imipramine N-demethylation is under a coregulatory pharmacogenetic control of CYP2C19, but not of CYP2D6. In conclusion, by taking into account that the incidence of the PMs of CYP2C19 is much greater (18-23%) than that of CYP2D6 (< 1%) in Japanese population, the individually predetermined assessment of the CYP2C19-mediated metabolic capacity of imipramine would be more valuable than that of the CYP2D6-mediated capacity for forecasting the steady-state concentrations of imipramine and desipramine in Japanese depressive patients, thereby attaining an individualized optimization of imipramine therapy. Obviously, a pharmacodynamic assessment study conducted simultaneously with predetermined CYP2C19 status is required for supporting this contention.

Treatment protocol for fractures of the odontoid process

Treatment results in 104 patients with odontoid fractures were reviewed. There were 2 type I, 62 type II, 32 type III fractures and eight epiphysiolyses in children <7 years old. Thirty-seven patients were managed nonoperatively using plaster casts, cervical braces, or halo devices. Sixty-seven patients were treated surgically including anterior screw fixation (ASF), posterior fusion (PF), and transoral anterior fusion (TAF). Plaster casts and cervical braces were effective for type I fractures and epiphysiolyses only. Halo devices provided successful results in stable type III fractures. ASF is the treatment of choice for most type II and unstable III fractures including some old cases. PF also provided successful union, although impaired cervical motion remained. It should be reserved for irreducible fractures, established nonunions, and as a salvage procedure. TAF should be limited to exceptional cases requiring anterior spinal cord decompression.

Structure and function of asterosaps, sperm-activating peptides from the jelly coat of starfish eggs

Jelly coat of starfish eggs has the capacity to activate homologous spermatozoa and induce the acrosome reaction. We have isolated 12 sperm-activating peptides (SAPs) from the egg jelly of the starfish, Asterias amurensis. Eleven SAPs were structurally identified by sequence analysis and electro-spray ionisation mass spectrometry. All of them are glutamine-rich tetratriacontapeptides with an intramolecular disulphide linkage between Cys8 and Cys32. They are much larger than sea urchin SAPs and do not show any significant sequence similarities to known proteins. Thus we have collectively named them asterosaps. The amino terminal region, where structural diversity of asterosaps is observed, is not important for their activity, whereas the disulphide linkage is essential. Asterosaps do not induce the acrosome reaction by themselves, but are able to induce the acrosome reaction in combination with an egg jelly glycoconjugate named ARIS. Furthermore, anti-asterosap rabbit antibody significantly decreased the acrosome reaction-inducing activity of the jelly solution and the activity was restored by addition of excess asterosap. These results support our hypothesis that the main physiological role of SAPs is the induction of the acrosome reaction in cooperation with two other jelly components, ARIS and Co-ARIS.

Identification of human cytochrome P450 isoforms involved in the stereoselective metabolism of mianserin enantiomers

To identify cytochrome P450 (CYP) isoform(s) involved in the major metabolic pathways of mianserin (MS) enantiomers in humans, we examined the metabolites formed from S-(+)- and R-(-)-MS using human liver microsomes and eight recombinant human CYP isoforms (i.e., CYP1A2, 2A6, 2B6, 2C9, 2C19, 2D6, 2E1 and 3A4). The mean V(max)/K(m) values of the 8-hydroxylation and N-oxidation were greater for S-(+)- than for R-(-)-MS, whereas that of the N-demethylation gave the opposite observation. When relationships were evaluated in microsomes from 10 human livers between the metabolism of substrates toward the respective CYP isoforms and stereoselective metabolism of MS at a low (5 microM) and at a high (200 microM) MS concentration, significant correlations existed in: 2-hydroxylation of desipramine vs. 8-hydroxylation of S-(+)-MS (r = 0.94, P < .01), O-deethylation of phenacetin vs. N-demethylation of S-(+)-MS (r = 0.85, P < .01) and R-(-)-MS (r = 0.69, P < .05) or N-oxidation of S-(+)-MS (r = 0.94, P < .01) at the low concentration; and 6 beta-hydroxylation of testosterone vs. three metabolic reactions of both MS enantiomers at the high concentration (r = 0.68-0.93, P < .05-.01). Quinidine inhibited the 8-hydroxylation of both enantiomers by < 40% of the respective control values. Furafylline and alpha-naphthoflavone showed a potent inhibitory effect on the N-demethylation and N-oxidation of S-(+)-MS (by up to < 50% of the respective control activities). In addition, troleandomycin inhibited the N-demethylation and N-oxidation of R-(-)-MS by < 50% of the respective control activities. Among the recombinant human CYP isoforms, CYP2D6, 2B6, 3A4 and 1A2 catalyzed the 8-hydroxylation, and CYP1A2 and 3A4 were involved exclusively in the N-oxidation, whereas CYP2B6, 2C19, 1A2, 3A4 and 2D6 showed a catalytic activity for the N-demethylation, for either or both of MS enantiomers. Taken together, the 8-hydroxylation for both MS enantiomers is mediated mainly via CYP2D6, whereas the N-demethylation for both the enantiomers and N-oxidation for S-(+)-MS are catalyzed mainly via CYP1A2. The two in vitro experiments suggested that CYP3A is involved to a certain extent in each of the stereoselective MS metabolic pathways.

[Rapidly deteriorating adult hydronephrosis due to an aberrant vessel: a case report]

Hydronephrosis due to ureteropelvic junction (UPJ) obstruction generally progresses gradually. We experienced a case of hydronephrosis due to UPJ obstruction deteriorating rapidly in an adult woman. In spite of percutaneous nephrostomy, 99mTc-DTPA renogram showed a non-functional pattern. A nephrectomy was done. Peri-operatively, the aberrant lower pole vessel was found to be obstructing the UPJ. The hydronephrosis deteriorated rapidly because the extrarenal pelvis dilated in the shape of box, became suspended from the aberrant vessel. Therefore, we believe that the box pelvis is one of the most important factors deteriorating hydronephrosis.

Antiviral activity of lignans and their glycosides from Justicia procumbens

Ten antiviral lignans, seven known (justicidins A, B, C and D, diphyllin, diphyllin apioside and diphyllin apioside-5-acetate) and three new compounds, justicidinosides A (justicidin C 6'-O-glucoside), B (justicidin A 6'-O-glucoside) and C (justicidin B 6'-O-glucoside), were isolated from a methanolic extract of the aerial parts of Justicia procumbens var. leucantha. Justicidins A and B, diphyllin, diphyllin apioside and diphyllin apioside-5-acetate showed strong antiviral activity (the MIC were less than 0.25 microgram ml-1, respectively) against vesicular stomatitis virus and low cytotoxicity (the MTC were larger than 31 micrograms ml-1, respectively) against cultured rabbit lung cells (RL-33).

[Intravesical oxybutynin hydrochloride in the treatment of urge incontinence in the elderly]

PURPOSE

This study was carried out to determine the effectiveness of intravesical oxybutynin hydrochloride on urinary urge incontinence in elderly people.

METHODS

The subjects consisted of 13 patients with an average age of 75 years who demonstrated uninhibited detrusor contraction on cystometrogram. The trial protocol consisted of a pretreatment cystometrogram followed by the intravesical administration of 10 ml solution containing 5 mg oxybutynin hydrochloride (pH 5.85). The urodynamic studies were repeated one hour later.

RESULTS

The mean bladder capacity before and after one hour of intravesical oxybutynin hydrochloride was 161 +/- 62 ml and 196 +/- 71 ml (mean +/- 1 S.D., n.s.). The rate of improvement was 15.4% (2 cases) in all 13 patients. Four patients out of 13 patients continued intravesical administration of the solution twice daily. Urinary incontinence disappeared in two patients and incontinence was markedly decreased in one. In the remaining patient, urinary incontinence did not change because of increased residual urine. Three patients have continued this therapy over one years and no side effects were observed. In these patients, residual urine volume did not increase.

CONCLUSION

It is suggested that intravesical oxybutynin hydrochloride is an effective option of therapy for intractable urge incontinence in elderly people, however, the immediate posttreatment cystometrogram was not predictive of the response to intravesical therapy on overactive bladder in the elderly.

Neuritogenic effect of natural iridoid compounds on PC12h cells and its possible relation to signaling protein kinases

We examined effect of iridoid glucosides, aucubin, catalpol, geniposide and gardenoside, and their enzymic hydrolysates on neurite outgrowth of PC12h cells. Except for aucubin, these glucosides induced neurite outgrowth at 0.1 microgram/ml and above in medium after 3 d of treatment. Hydrolysates of the four glucosides all caused neuritogenesis. Geniposide hydrolysate enhanced responses of cells to carbachol and KCl-induced depolarization in terms of cytoplasmic free-calcium concentration. The aglucone of geniposide, genipin, also promoted neurite outgrowth in a dose-dependent manner (ED50 = 0.7 microM). The neuritogenic effect of genipin was partially or considerably inhibited in the presence of H-89 and genistein. All the results presented suggest that certain iridoid compounds can induce neuronal differentiation in PC12h cells through activation of components of the intracellular signal transduction pathway.

Neonatal mouse hip joint and hindlimb anomalies induced by prenatal exposure to Ara-C

To induce hip joint anomalies and assess their relationship with hindlimb anomalies, pregnant mice (Jcl;ICR) were injected intraperitoneally with a single dose of 5.0 or 7.5 mg/kg of cytosine arabinoside (Ara-C) on dg 8, 9.5, or 11. On the 24th postnatal day, surviving offspring were stained by alizarin red S and anomalies were observed. Hip joint anomalies were observed only in one group exposed to 7.5 mg/kg on dg 9.5; the incidence of the hip joint anomalies in this group was about 30%. The types of hip anomalies observed were femoral shaft dysplasia, pseudoarthrosis of the femur, femoral head dysplasia, acetabular dysplasia, fusion between the femoral head and acetabulum, and pseudoarthrosis of the coxal bone. All of these anomalies were associated with preaxial hyperplasia of the hind paws and lower leg anomalies. Strangely, while newborns with no hip joint anomalies had a fairly high rate of oligodactyly, no newborn with hip joint anomalies had oligodactyly.

A kinetic and dynamic study of oral alprazolam with and without erythromycin in humans: in vivo evidence for the involvement of CYP3A4 in alprazolam metabolism

OBJECTIVE

To assess the possible involvement of CYP3A4 in the metabolism of alprazolam in vivo.

METHOD

Twelve healthy male volunteers were randomly allocated to one of the two different treatment sequences, placebo-erythromycin or erythromycin-placebo, with an at least 6-week washout period between the two trial phases. Each volunteer received 400 mg erythromycin or matched placebo given orally three times a day for 10 days and an oral dose (0.8 mg) of alprazolam on the posttreatment day 8. Plasma concentration of alprazolam was measured up to 48 hours after the administration, and psychomotor function was assessed at each time of blood samplings with use of the Digit Symbol Substitution Test, visual analog scale, and Udvalg for kliniske undersøgelser side effect rating scale.

RESULTS

Erythromycin significantly (p < 0.001) increased the area under the plasma concentration-time curves (200 +/- 43 versus 322 +/- 49 ng . hr/ml from 0 to 48 hours and 229 +/- 52 versus 566 +/- 161 ng . hr/ml from 0 hour to infinity), decreased the apparent oral clearance (1.02 +/- 0.31 versus 0.41 +/- 0.12 ml/min/kg), and prolonged the elimination half-life (16.0 +/- 4.5 versus 40.3 +/- 14.4 hours) of alprazolam. However, any psychomotor function variables did not differ significantly between the erythromycin and placebo trial phases.

CONCLUSION

This study suggests that erythromycin, an inhibitor of CYP3A4, inhibits the metabolism of alprazolam, providing an in vivo evidence for the involvement of CYP3A4 in its metabolism. However, the kinetic change of alprazolam by erythromycin does not result in the pharmacodynamic change of this triazolobenzodiazepine, at least after single dosing.

Inhibition of Mac-1-dependent leukocyte adhesion by Y-24180, an anti-inflammatory agent, in mice

Y-24180 (4-(2-chlorophenyl)-2-[2-(4-isobutylphenyl)ethyl]-6,9-dimethyl-6H-thieno[3,2-f][1,2,4]triazolo[4,3-a][1,4]-diazepine), an antagonist of platelet-activating factor (PAF), has been already clarified to suppress the expression of an adhesion molecule, Mac-1, on human neutrophils in the previous in vitro study. In the present paper, we examined the effect of Y-24180 on in vivo Mac-1 expression on mouse neutrophils using a lipopolysaccharide-induced leukocyte reduction model in which Mac-1-dependent infiltration of neutrophils was involved. Prophylactic oral administration of Y-24180 inhibited the induction of Mac-1-strongly positive neutrophils by intraperitoneal injection of lipopolysaccharide and prevented the reduction of leukocyte number. In contrast, WEB 2086 (3-[4-(2-chlorophenyl)-9-methyl-6H-thieno[3,2-f][1,2,4]triazolo[4,3-a][1,4]diazepine-2-yl]-1-(4-morpholinyl)-1-propanone), another PAF antagonist, showed little effect. PAF injection failed to induce the Mac-1-strongly positive neutrophils in peripheral blood and the reduction of circulating leukocytes, indicating that PAF was not concerned with the lipopolysaccharide-induced up-regulation of Mac-1 expression and leukocyte reduction. Y-24180 inhibited the leukocyte infiltration also in the thioglycollate medium-induced peritonitis, which was mediated by Mac-1-dependent leukocyte adhesion. These results indicate that Y-24180 inhibits the leukocyte infiltration into the inflamed sites by suppressing Mac-1 expression on leukocytes in vivo and can contribute to the improvement of inflammatory diseases in which the Mac-1-dependent leukocyte adhesion is involved.

Efficient Nd:YAG laser end pumped by a high-power multistripe laser-diode bar with multiprism array coupling

A 10-W laser-diode bar, a multistripe monolithic laser-diode array, has been used to end pump Nd:YAG. Twelve beams emitted from 12 stripes, spaced 800 µm apart, of a 1-cm linear diode array were collimated with a multiprism array consisting of 14 prismlets with 800-µm width to pump the Nd:YAG facet. The maximum Nd:YAG cw output power at 1064 nm of 3 W was obtained at 10-W laser-diode-bar power with a slope efficiency of 35%, and a TEM(00) spatial mode with values of beam-quality factor M(2) of 1.29 and 1.76 in the planes perpendicular and parallel to the junction, respectively. A pulse width of 25.2 ns (1-kHz repetition) was obtained in acousto-optic Q-switched operation.

Simple and selective assay of 4-hydroxymephenytoin in human urine using solid-phase extraction and high-performance liquid chromatography with electrochemical detection and its preliminary application to phenotyping test

A simple and selective HPLC method for the determination of 4-hydroxymephenytoin (4-OH-M) in human urine, using a controlled potential coulometric detector equipped with a dual working electrode cell of fully porous graphite, has been developed. After acid hydrolysis of urine, 4-OH-M and the internal standard (I.S.), 5-hydroxy-1-tetralone, were extracted from urine by means of a Bond Elut Certify LRC column. The extracts were chromatographed on a reversed-phase mu Bondapak C18 column using methanol-50 mM KH2PO4 (pH 4.0) (30:70, v/v) as the mobile phase at a flow-rate of 1.0 ml/min. Electrochemical detection at applied potential of 800 mV resulted in a limit of quantitation of 0.76 micrograms/ml. The method showed a satisfactory sensitivity, precision, accuracy, recovery and selectivity. The present method was applied to the phenotyping test in thirteen Japanese healthy volunteers who received an oral 100-mg racemic mephenytoin. The phenotypes determined by the present method were found to be in agreement with those obtained with the reported customary assay based on gas chromatography.

[Renal cell carcinoma accompanied with ossification: a case report]

Renal cell carcinoma accompanied with ossification reported in Japan is very rare. We report a case of renal cell carcinoma with ossification pathologically in a 61-year-old woman. She suddenly presented with hypercalcemia that caused acute renal failure, 6 months after the operation and died shortly thereafter. We discuss the relationship between the tumor and the hypercalcemia.

Cytotoxic xanthones from Garcinia hanburyi

Eleven novel cytotoxic xanthones, gambogin, morellin dimethyl acetal, isomoreollin B, moreollic acid, gambogenic acid, gambogenin, isogambogenin, desoxygambogenin, gambogenin dimethyl acetal, gambogellic acid and hanburin were isolated together with four known xanthones, gambogic acid, isomorellin, morellic acid and desoxymorellin, from the dry latex of Garcinia hanburyi. The structures were elucidated by a detailed spectroscopic analysis.

Simultaneous measurement of proguanil and its metabolites in human plasma and urine by reversed-phase high-performance liquid chromatography, and its preliminary application in relation to genetically determined S-mephenytoin 4'-hydroxylation status

A simple high-performance liquid chromatographic (HPLC) assay method was developed for the measurement of proguanil (PG) and its major metabolites, cycloguanil (CG) and 4-chlorophenyl-biguanide (CPB), in human plasma and urine. The assay allowed the simultaneous determination of all analytes in 1 ml of plasma or 0.1 ml of urine. The detection limits of PG, CG, and CPB, defined as the signal-to-noise ratio of 3, were 1 and 5 ng/ml for plasma and urine samples, respectively. Recoveries of the analytes and the internal standard (pyrimethamine) were > 62% from plasma and > 77% from urine. Intra-assay and interassay coefficients of variation for all analytes in plasma and urine were < 10% except for the values of CG and CPB, which ranged from 10% to 15% at one or two concentrations among 4-5 concentrations studied. The clinical applicability of the method was assessed by the preliminary pharmacokinetic study of PG, CG, and CPB in six healthy volunteers with the individually known phenotypes (extensive and poor metabolizers) of S-mephenytoin 4'-hydroxylation, suggesting that individuals with a poor metabolizer phenotype of S-mephenytoin have a much lower capacity to bioactivate PG to CG compared with the extensive metabolizers.

A novel immunosuppressant, FTY720, with a unique mechanism of action, induces long-term graft acceptance in rat and dog allotransplantation

A new compound with an immunosuppressive property was purified from culture filtrates of Isaria sinclairii and was chemically modified to FTY720. Rat spleen cells incubated with FTY720 demonstrated features characteristic of apoptosis--such as the absence of surface microvilli, chromatin condensation, and the formation of apoptotic bodies--by electron microscopy, and genemic DNA fragmentation by agarose gel electrophoresis. When FTY720 was administered in liver-allografted rats at a dose of 0.5 mg/kg from day 1 to day 14 after transplantation, the recipients survived significantly longer than the control group. Pretransplant treatment with 5 mg/kg of FTY720 one day before and on the day of grafting induced a remarkable prolongation of recipient survival, and three of 10 recipients survived for longer than 50 days. Furthermore, administration of FTY720 at 5 mg/kg on days 3 and day 4 after grafting also prolonged survival. In canine kidney allografting, a pretransplant 2-day course of FTY720 at 5 mg/kg prolonged graft survival. Daily administration of FTY720 in combination with CsA resulted in a significant prolongation of graft survival in a synergistic manner. In addition, FTY720 appeared to be nontoxic in canine recipients. These results demonstrated that FTY720, having a unique mechanism of action, induces long-term graft acceptance in rat and dog allotransplantation.