Expression of Bfl-1 in normal and tumor tissues: Bfl-1 overexpression in cancer is attributable to its preferential expression in infiltrating inflammatory cells

Bfl-1, a member of the Bcl-2 gene family, blocks p53-mediated apoptosis and has oncogenic transforming activity. In normal tissues, the transcript of Bfl-1 is expressed abundantly in bone marrow and at a low level in several other tissues. In previous experiments, elevated expression of Bfl-1 was observed by Northern analysis of stomach cancer samples. To study the role of Bfl-1 in normal cell development and in tumorigenesis, we have analyzed the expression of Bfl-1 in normal and tumor tissues by the in situ hybridization technique. The Bfl-1 transcript was detected in the white pulp of the spleen and in the germinal center of lymphatic tissues. In tumor tissues, its expression was preferentially detected in infiltrating inflammatory cells rather than in cancer cells, suggesting that Bfl-1 is not involved in tumorigenesis.

Effect of stem cell factor, interleukin-6, nitric oxide and transforming growth factor-beta on the osteoclast differentiation induced by 1 alpha,25-(OH)2D3 in primary murine bone marrow cultures

Osteotropic hormones and cytokines are involved in the differentiation of osteoclast progenitors from haematopoietic stem cells to multinucleated osteoclasts which mediate bone resorption. Stem cell factor, interleukin-6, nitric oxide, and transforming growth factor-beta are implicated in the regulation of bone resorption by osteoclast. We test whether stem cell factor, interleukin-6, nitric oxide, and transforming growth factor-beta affect the generation of osteoclast-like multi-nucleated cells induced by 1 alpha,25-(OH)2D3. 1 alpha,25-(OH)2D3 increase the generation of osteoclast-like cells retaining osteoclast characteristics including multinuclearity and positive staining for tartrate-resistant acid phosphatase. Combined treatment of stem cell factor with interleukin-6 synergistically potentiates the ability of 1 alpha,25-(OH)2D3 to generate tartrate-resistant acid phosphatase-positive multinucleated cells. However, either stem cell factor or interleukin-6 alone does not induce the generation of tartrate-resistant acid phosphatase-positive multinucleated cells. Transforming growth factor-beta produces a biphasic effect on osteoclast generation induced by 1 alpha,25-(OH)2D3. Transforming growth factor-beta stimulates osteoclast generation at low concentration (0.1 ng/ml) whereas it suppresses the formation of osteoclast-like cell at higher concentration (1 ng/ml). Sodium nitroprusside, a donor of nitric oxide, almost completely inhibits the generation of 1 alpha,25-(OH)2D3-induced osteoclast at high concentration (100 microM), but it significantly enhances the osteoclast generation at low concentrations (3 microM). These results suggest that stem cell factor, interleukin-6, transforming growth factor-beta, and nitric oxide interact with 1 alpha,25-(OH)2D3 to modulate the differentiation of hematopoietic precursors toward committed osteoclast precursors.

KCB-328: a novel class III antiarrhythmic agent with little reverse frequency dependence in isolated guinea pig myocardium

The effects of 1-(2-amino-4-methanesulfonamidophenoxy)-2-[N-(3,4-dimethoxypheneth yl)-N-methylamino] ethane hydrochloride (KCB-328), in comparison with those of dofetilide, were studied on the action potentials (APs) of isolated guinea pig papillary muscles. KCB-328 (0.003-3 microM) concentration-dependently prolonged the AP duration at 90% repolarization (APD90) at 1- and 3-Hz pacing, and the concentration-response relations at 1 and 3 Hz resemble each other. Dofetilide (0.001-1 microM) also produced the concentration-dependent prolongation of APD90 but more pronouncedly at 1 than at 3 Hz, demonstrating the reverse frequency-dependent effect. KCB-328 at 0.03, 0.1, 0.3, and 1 microM increased APD90 by 11 +/- 1, 19 +/- 1, 25 +/- 1, and 29 +/- 1% at 3 Hz and by 9 +/- 1, 19 +/- 2, 27 +/- 2, and 33 +/- 2% at 1 Hz, respectively. Prolongation of the effective refractory period (ERP) by each drug is parallel to those of APD90 at each pacing frequency. KCB-328 modified neither the maximal velocity of depolarization, amplitude of AP, and resting membrane potential in the fast APs, nor any parameters of the slow APs. In a separate experiment, the effects of KCB-328 on the ERP of contractile response (ERPc) of excised guinea-pig papillary muscles also were studied at 1 and 3 Hz. KCB-328 (0.01-10 microM) lengthened the ERPc in a concentration-dependent and frequency-independent manner as in the electrophysiologic results. This frequency-independent ERPc prolongation by KCB-328 was not influenced by increased extracellular K+ concentration from 4 to 10 mM. These results suggest that KCB-328 might be a selective class III agent with effects that are relatively frequency independent.

Cardiovascular pharmacology of SKP-450, a new potassium channel activator, and its major metabolites SKP-818 and SKP-310

The cardiovascular effects of SKP-450, a newly synthesized potassium channel activator, and its two major metabolites SKP-818 and SKP-310 were evaluated on isolated rat aorta and in freely moving rats and anesthetized beagle dogs. The rank order of potency in relaxing rat aorta precontracted with norepinephrine was SKP-450 > SKP-818 > Lemakalim > SKP-310 (EC50: 0.12, 0.55, 0.71 and 5.89 mumol/l, respectively). In rats, SKP-450, SKP-818 and lemakalim (3-100 micrograms/kg, i.v.) induced a dose-dependent decrease in mean arterial pressure (MAP; ED20: 9.8, 11.7 and 22.4 micrograms/kg, respectively) followed by reflex tachycardia. In dogs, SKP-818 and SKP-310 (0.3-1,000 micrograms/kg, i.v.) had quite similar hemodynamic profiles to SKP-450 but with a smaller potency. SKP-450, SKP-818 and SKP-310 dose-relatedly decreased MAP (ED20: 2.6, 4.2 and 588.8 micrograms/kg, respectively). They slightly increased left ventricular positive dP/dtmax with a transient decrease at the highest dose, while inducing a dose-related decrease in rate-pressure product, tension time index and systolic time. SKP-450, SKP-818 and SKP-310 induced a marked dose-dependent increase in coronary blood flow (Emax: 172.8, 257.9 and 178.7%, respectively) with less effects on blood flow through other arteries. Glybenclamide antagonized all the hemodynamic effects of SKP-450 in rats and dogs, whereas propranolol antagonized its reflex tachycardia in rats. These results indicate that SKP-450 is a potent coronary and peripheral vasodilator in rats and dogs activating ATP-sensitive potassium channels and that SKP-818 and SKP-310 exert a similar hemodynamic profile to the parent compound with equi- and weaker potency, respectively.

CYP3A4-mediated oxidation of lisofylline to lisofylline 4,5-diol in human liver microsomes

The cytochrome P450s responsible for the conversion of lisofylline, a drug being developed to prevent the complications of high-dose chemotherapy, to lisofylline 4,5-diol, one of two principal metabolites in human liver microsomes, were evaluated. Lisofylline diol formation in microsomes prepared from five adult human livers was biphasic, with respective Km values of 0.0230+/-0.015 and 4.23+/-2.8 mM (mean +/- SD) and respective Vmax values of 0.0565+/-0.052 and 0.429+/-0.15 nmol/min/mg of protein. Through studies with isoform selective chemical inhibitors, CYP3A4 was implicated as the low Km enzyme from 89.0+/-11.2% inhibition of lisofylline 4,5-diol formation by troleandomycin at 50 microM substrate and CYP2A6 was implicated as the high Km enzyme. The formation of lisofylline 4,5-diol by these enzymes was confirmed with cDNA-expressed human CYP3A4 and CYP2A6.

Reversal of multidrug resistance by novel verapamil analogs in cancer cells

The present study was performed to evaluate the ability of KR-30032 and KR-30035 to overcome multidrug resistance (MDR) by measuring the cytotoxicity and the accumulation rate of rhodamine. Additionally, the adverse cardiac toxicity of KR-30032 and KR-30035 was evaluated by measuring the changes of tension in isolated rat aorta and left ventricular pressure (LVP) in guinea pig heart. KR-30035 potentiated the paclitaxel-induced cytotoxicity to HCT15 [P-glycoprotein (P-gp)-expressed cells] to over 15-fold greater than that of verapamil and KR-30032 was equipotent with verapamil (EC50: 0.07, 5.0 and 3.3 nM at 1.0 microg/ml). KR-30032 and KR-30035 were without effect on cytotoxicity to SK-OV-3 cells (P-gp-non-expressing cells), as well as to tamoxifen-induced cytotoxicity in the above cell types. Maximal rhodamine accumulation rates with KR-30032, KR-30035 and verapamil were 290, 291 and 271% in HCT15 cells; and 451, 970 and 440% in HCT15/CL02 cells, respectively. KR-30032 and KR-30035 were 20- to 25-fold less potent than verapamil in relaxing aorta (EC50: 8.13, 6.40 and 0.32 microM, respectively) and were 12- to 35-fold less potent than verapamil in decreasing LVP in isolated hearts (EC50: 41.8, 14.1 and 1.2 microM, respectively). The results of this study suggest that KR-30032 and KR-30035 are active modulators of MDR with potentially minimal cardiovascular toxicity.

Hemodynamic profile of SKP-450, a new potassium-channel activator

Hemodynamic profiles of SKP-450, a newly synthesized potassium-channel activator, were evaluated in conscious hypertensive rats of several types, and in anesthetized and conscious beagle dogs. In freely moving conscious rats, orally administered SKP-450 (0.03-0.3 mg/kg) dose-dependently decreased arterial pressure in spontaneously hypertensive rats (SHRs), renally hypertensive rats (RHRs), DOCA/salt-induced hypertensive rats (DHRs), and normotensive rats (NRs) with a greater potency than lemakalim except in DHRs (ED20 values: SKP-450, 0.021, 0.013, 0.024, and 0.034 mg/kg; lemakalim, 0.107, 0.018, 0.016, and 0.063 mg/kg, respectively). The blood pressure-reducing effects of SKP-450 reached their maximum within 30 min and lasted for approximately 4 h in all rats, and >6 h, particularly, in SHRs. In NRs, pretreatment with glibenclamide (20 mg/kg, i.v.) antagonized the hypotensive effect of SKP-450, whereas propranolol (2 mg/kg, i.v.) antagonized the tachycardiac response of SKP-450 (0.03 mg/kg, i.v.) without affecting its hypotensive response in NRs. In anesthetized beagle dogs, intraduodenally administered SKP-450 (0.003-0.03 mg/kg) dose-relatedly decreased arterial pressure (ED20 value, 0.007 mg/kg) for > or =3 h with its peak effects reached within 15 min and without significant changes in heart rate (HR). Antihypertensive effects of SKP-450 were accompanied by concurrent reduction in total peripheral resistance and dose-dependent increase in cardiac output. Indirect measures of myocardial oxygen demand such as rate-pressure product, tension-time index, and systolic time interval were dose-dependently decreased by SKP-450 without significant change in left ventricular dP/dt(max). SKP-450 significantly increased coronary blood flow and decreased coronary vascular resistance dose-dependently with a rapid onset of action and long duration of >4 h (maximal changes, 276 and 83.7% at 0.03 mg/kg, respectively). In conscious dogs, orally administered SKP-450 (0.03-0.3 mg/kg) produced a dose-related decrease in arterial pressure for > or =3 h, with its peak effects reached within 20 min (ED20 value, 0.030 mg/kg) accompanied by tachycardia. These results suggest that SKP-450 is a potent, orally active peripheral vasodilator activating ATP-sensitive potassium channels.

Identification of new urinary metabolites of famprofazone in humans

Urinary metabolites of famprofazone following oral administration in humans were identified by gas chromatography-mass spectrometry with electron impact-ionization and comparison with the spectra and retention times of authentic standards. The metabolites were determined following selective derivatization with N-methyl-bis-trifluoroacetamide (MBTFA) and N-methyl-N-trimethyl silyl trifluoroacetamide (MSTFA). Famprofazone was rapidly and extensively metabolized by N-dealkylation, beta-hydroxylation, and p-hydroxylation. The major metabolite, representing approximately 15% of the dose, was methamphetamine. The other metabolites, which were present in minor amounts, were amphetamine, norephedrine, norpseudoephedrine, ephedrine, pseudoephedrine, p-hydroxyamphetamine, p-hydroxymethamphetamine, and p-hydroxydemethyl famprofazone.

Cardioprotective effects of KR-30450, a novel K+(ATP) opener, and its major metabolite KR-30818 on isolated rat hearts

The cardiac effects of KR-30450 ((-)-(2R)-2-([1,3]-dioxolan-2-yl)-2-methyl-4-(2-oxopyrrolidin++ +-1-yl)-6-nitro-2H-1-benzopyran), a newly synthesized potassium channel activator, and its major metabolite KR-30818 ((-)-(2R)-2-hydroxymethyl-2-methyl-4-(2-oxopyrrolidin-1-yl)-6-nitr o-2H-1-benzopyran) were compared with those of lemakalim, a prototype of this class, in isolated globally ischemic rat hearts. KR-30450 and KR-30818 significantly improved reperfusion cardiac function (LVDP, left ventricular developed pressure; double product, LVDP x heart rate/1000), their potency being 5.2-fold and 0.7-fold greater than lemakalim (ED50 for recovering predrug double product: 0.10, 0.80 and 0.54 microM, respectively). KR-30450 and KR-30818 significantly attenuated reperfusion contracture and lactate dehydrogenase release with potency greater than and equal to lemakalim, respectively. They significantly increased time to contracture (TTC) during ischemia in a dose-dependent manner with a greater potency than lemakalim (EC25 for increasing TTC: 1.2, 2.1 and 3.2 microM, respectively). The protective effects of three compounds on the measured parameters were reversed by glyburide, a selective K+(ATP) blocker. In non-ischemic hearts, KR-30450 and lemakalim exerted weak negative inotropism at high concentrations and KR-30818 had no effects, whereas the three compounds significantly increased coronary flow at doses studied. Glyburide completely reversed preischemic cardiodepressant effects of these compounds but not their effects on coronary flow. In conclusion, KR-30450, a recently developed K+(ATP) opener, exerted more potent cardioprotective effects than lemakalim, and its major metabolite KR-30818 may play a significant role in its action in vivo.

Treatment of antecubital pterygium in the nail-patella syndrome

Antecubital pterygium is rare in the nail-patella syndrome but common in the multiple pterygium syndrome and aplasia of the trochlea. It is known that there is the rebound phenomenon after treatment of congenital joint contracture. We describe the poor functional results due to rapid recurrence of the flexion contracture treated with the Ilizarov method for an antecubital pterygium in the nail-patella syndrome.

Expression of a novel Bcl-2 related gene, Bfl-1, in various human cancers and cancer cell lines

The expression of Bfl-1 gene, a novel Bcl-2 related gene, was determined by Northern blot analysis using a radiolabeled cDNA specific for Bfl-1 gene in 82 surgically resected tissue specimens of 28 gastric cancers, 15 colon cancers, nine breast cancers, eight bone and soft tissue sarcomas, five ovarian cancers, nine colon adenomas and eight gastric adenomas. A high rate of expression was observed in gastric and colon cancer, at 86 and 93%, respectively. In breast cancer, bone and soft tissue sarcoma and ovarian cancer, the expression rate was 33, 25 and 40%, respectively. In stomach cancer, the expression rate of Bfl-1 gene in metastatic lymph nodes was 82%, which was higher than 50% of the primary sites (p < 0.02). The intensity of RNA bands of the gastric cancer specimens was compared according to the stage, demonstrating that there was no difference in the expression levels of Bfl-1 gene between the stages in both primary sites and metastatic lymph nodes. Bfl-1 gene was expressed in three (33%) out of nine adenomas of the colon, while it was not detected in all eight gastric adenomas, We also examined the RNA expression of Bfl-1 gene in 22 human cancer cell lines consisting of five stomach cancer, four squamous cell carcinoma, three lung cancer, three cervical cancer, two colon cancer, two brain cancer, two leukemia and one osteosarcoma cell lines. Bfl-1 gene band was detected in one (5%) cervical cancer cell line, SiHa. The results of cancer tissue specimens indicate that Bfl-1 gene may play an important role in carcinogenesis of human cancers and may be involved in a relatively early phase of the adenoma-carcinoma sequence in colon cancer development. However, the mechanism responsible for the very low rate of expression in established cell lines is not clearly understood and further investigation is necessary to clarify the mechanism involved.

Novel multidrug-resistance modulators, KR-30026 and KR-30031, in cancer cells

The present study was performed to evaluate the ability of KR-30026 and KR-30031 to overcome multidrug resistance (MDR) by measuring the cytotoxicity of paclitaxel and the rate of rhodamine accumulation, which were then compared with verapamil. KR-30026 potentiated the paclitaxel-induced cytotoxicity of HCT15 to over 60 fold greater than that of verapamil, and KR-30031 was equipotent with verapamil (EC50: 0.00066, 0.04 and 0.05 nM at 4.0 micrograms/ml, respectively). KR-30026 and KR-30031 were without effect on paclitaxel-induced cytotoxicity to SK-OV-3 cells, as well as on tamoxifen-induced cytotoxicity to HCT15, HCT15/CL02 and SK-OV-3 cells. Maximal rhodamine accumulation by KR-30026, KR-30031 and verapamil were similar in HCT15 cells, while KR-30026 was more potent than verapamil in HCT15/CL02 cells (721 and 440%, respectively). To evaluate the cardiac toxicity of KR-30026 and KR-30031, the changes of tension in isolated rat aorta and left ventricular pressure (LVP) in guinea pig heart were determined; KR-30026 and KR-30031 were 15-40 and 25-70 fold less potent than verapamil, respectively. These results suggest that KR-30026 and KR-30031 are active modulators of MDR with potentially minimal cardiovascular toxicity.

Phospholipase C isozymes selectively couple to specific neurotransmitter receptors

A variety of extracellular signals are transduced across the cell membrane by the enzyme phosphoinositide-specific phospholipase C-beta (PLC-beta) coupled with guanine-nucleotide-binding G proteins. There are four isoenzymes of PLC-beta, beta1-beta4, but their functions in vivo are not known. Here we investigate the role of PLC-beta1 and PLC-beta4 in the brain by generating null mutations in mice: we found that PLCbeta1-/- mice developed epilepsy and PLCbeta4-/- mice showed ataxia. We determined the molecular basis of these phenotypes and show that PLC-beta1 is involved in signal transduction in the cerebral cortex and hippocampus by coupling predominantly to the muscarinic acetylcholine receptor, whereas PLC-beta4 works through the metabotropic glutamate receptor in the cerebellum, illustrating how PLC-beta isoenzymes are used to generate different functions in the brain.

Dicistronic tagging of genes active in embryonic stem cells of mice

A gene-trap vector, pWH14, has been developed to tag genes expressed in embryonic stem (ES) cells of the mouse. The approach relies on the ability of the endogenous promoter to drive promoterless neo-IRES-lacZ construct producing a dicistronic mRNA consisting of the neomycin-resistance (neo) gene and the beta-galactosidase gene sequence. The neo gene produces a chimeric protein with the truncated product of the tagged gene and serves as a selectable marker for an insertion into an expressed gene. The internal ribosome entry site (IRES) sequence from murine encephalomyocarditis virus allows the translation of the second cistron, lacZ, to produce beta-galactosidase that can be used as a reporter for the expression of the tagged gene. The pWH14 vector was introduced into ES cells by electroporation, and the cells were selected for G418-resistance. About 50% of the G418-resistant colonies were stained positive for the beta-galactosidase activity. Southern analysis showed that each clone had one or more vector sequences integrated. Northern blot analysis of the clones positive for beta-galactosidase indicated that the fused RNAs containing the neo and the beta-gal genes were derived from the endogenous promoters of the tagged genes. Seven clones were chosen and injected into blastocysts, and chimeras were obtained. Two of the gene-trap insertions (wh14.1 and wh14.3) were transmitted through germ-line. In these two lines, the pattern of lacZ expression was restricted to early stages of embryos. This gene-trap vector may provide a means for tagging and studying the active genes in vivo in early embryogenesis.

Induction of IP-10 chemokine promoter by measles virus: comparison with interferon-gamma shows the use of the same response element but with differential DNA-protein binding profiles

Measles virus (MV) and interferon (IFN)-gamma induced IP-10 chemokine mRNA in U373 glioblastoma cells. The minimal response element for both MV and IFN-gamma was localized between nucleotide -231 and -153 of muIP-10 promoter, which contains an IFN-stimulated response element (ISRE) and the distal NF-kappa Bd site. Mutation of individual elements showed that ISRE and NF-kappa Bd were required to function together. DNA-protein binding profiles with the minimal response element showed that IFN-gamma induced a complex consisting of STAT1 while MV induced a complex consisting of p50 and p65 in the absence of new protein synthesis. IFN-gamma and MV also induced IRF-1 DNA binding activity which persisted for longer time periods with IFN-gamma stimulation. Despite the functional requirement of both ISRE and NF-kappa Bd elements, different combinations of DNA binding factors are used in the induction of IP-10 by MV or IFN-gamma.

Metabolism of selegiline in humans. Identification, excretion, and stereochemistry of urine metabolites

Nine urinary metabolites of selegiline hydrochloride [N-methyl-N-propargyl [2-phenyl-1-methyl)ethylammonium chloride], a monoamine oxidase inhibitor, after administration to humans were identified. Their identifies were confirmed by comparison of the spectra from GC/MS of peaks with those of authentic compounds. The following metabolites and unchanged drug (selegiline) were detected in urine: (R)-desmethylselegiline, (R)-methamphetamine, (R)-amphetamine, (1S,2R)-norephedrine, (1R,2R)-norpseudoephedrine, (1S,2R)-ephedrine, (1R,2R)-pseudoephedrine, (R)-p-hydroxyamphetamine, and (R)-p-hydroxymethamphetamine. The metabolites excreted 2 days after administration of 2.5-10 mg of selegiline hydrochloride amounted to 44-58% of the dose. Selegiline was metabolized by three distinct pathways: N-dealkylation, beta-carbon hydroxylation, and ring-hydroxylation. The major metabolite was (R)-methamphetamine. During metabolism, no racemic transformation occurred and beta-carbon hydroxylation showed apparently product stereoselectivity.

Simultaneous quantification of insecticides including carbaryl in drinking water by gas chromatography using dual electron-capture and nitrogen-phosphorus detection

A rapid and simple gas chromatographic method for the simultaneous determination of malathion, parathion, fenitrothion, diazinon and carbaryl in drinking water is presented. A fused-silica SE-54 column was used for the separation of the insecticides and was split into two specific detectors; electron-capture and nitrogen-phosphorus detectors by using column switching. A water sample was extracted with methylene chloride. The organic phase was evaporated and the residue was derivatized with pentafluoropropionic acid anhydride. The detection limit was below 0.1 ng/ml and the calibration curves showed good linearity with r = 0.998 approximately 1.000. The method was sensitive, reproducible and simple enough to permit the reliable routine analysis of the pesticides in drinking water.

Interaction of nitric oxide and the renin angiotensin system in renal hypertensive rats

We investigated the interaction between nitric oxide and the renin angiotensin system in regulating isolated aortic tension and mean arterial pressure in renal hypertensive rats (RHR). Acetylcholine (ACh) relaxed aorta precontracted with norepinephrine from RHR significantly less than that from normotensive rats (NR) (Emax: 34.3% and 86.0%, respectively, P < 0.01). The ACh-induced relaxation was significantly enhanced by losartan (P < 0.05) and completely abolished by removal of endothelium or NG-nitro-L-arginine methyl ester (L-NAME). ACh lowered the mean arterial pressure slightly less effectively in RHR than in NR (6.8 and 13.0 mmHg, respectively, at 0.1 microgram/kg), whereas the depressor effect was reduced by L-NAME (-15.5 and 10.3 mmHg, respectively, at 0.1 microgram/kg), but rather enhanced by further treatment with losartan (9.9 (P < 0.05) and 17.3 mmHg, respectively, at 0.1 microgram/kg). Angiotensin II induced similar contractile and pressor responses in both RHR and NR, and these effects were significantly enhanced by L-NAME, except for the pressor effect in RHR. L-NAME induced a similar pressor response in RHR and NR (15.9 and 15.2 mmHg, respectively, at 0.1 mg/kg), the effect being decreased by pretreatment with losartan. Losartan induced a depressor response that was smaller in RHR than in NR (34.0 and 48.8 mmHg, respectively, at 0.3 mg/kg), and the response was significantly reduced by L-NAME. These results suggest that nitric oxide interacts with the renin angiotensin system to control the vascular tension and systemic arterial circulation in RHR.

Helicobacter pylori infection and the risk of gastric cancer among the Korean population

Helicobacter pylori infection has been associated with chronic atrophic gastritis, a precursor of gastric cancer. We conducted a prospective, case-controlled study to investigate whether H. pylori infection increases the risk of gastric cancer in Korean people with a high risk of gastric cancer. We enrolled 160 gastric cancer patients who were confirmed by endoscopic biopsy during 1994 and 160 age-matched control subjects with non-ulcer dyspepsia were compared to document the relationship between H. pylori infection and gastric cancer. The presence of H. pylori infection was determined by the rapid urease test and/or histology by Wright-Giemsa staining. The overall presence of H. pylori infection was 60% in gastric cancer patients and 51.9% in age-matched control subjects (odds ratio 1.39; 95% confidence interval 0.894-2.17; P = 0.143). Carcinomas of cardia, body and antrum were not associated with H. pylori infection (odds ratio 1.43, 1.69 and 1.29, respectively; 95% confidence interval, 0.271-7.52, 0.787-3.62 and 0.689-2.43, respectively; P = 0.178, 0.177 and 0.642, respectively) nor was the intestinal or diffuse type of cancer (odds ratio 1.39 and 1.40, respectively; 95% confidence interval 0.791-2.45 and 0.681-2.87, respectively; P = 0.250 and 0.835, respectively). Gender was not a risk for gastric cancer. In contrast to previous studies, these results do not provide evidence of H. pylori infection for gastric carcinogenesis in Korea.

Biotransformation for L-ephedrine production

L-ephedrine is widely used in pharmaceutical preparations as a decongestant and anti-asthmatic compound. One of the key intermediates in its production is L-phenylacetylcarbinol (L-PAC) which can be obtained either from plants (Ephedra sp.), chemical synthesis involving resolution of a racemic mixture, or by biotransformation of benzaldehyde using various yeasts. In the present review, recent significant improvements in the microbial biotransformation are assessed for both fed-batch and continuous processes using free and immobilised yeasts. From previous fed-batch culture data, maximal levels of L-PAC of 10-12 gl-1 were reported with yields of 55-60% theoretical based on benzaldehyde. However, recently concentrations of more than 22 gl-1 have been obtained using a wild-type strain of Candida utilis. This has been achieved through optimal control of yeast metabolism (via microprocessor control of the respiratory quotient, RQ) in order to enhance substrate pyruvate production and induce pyruvate decarboxylase (PDC) activity. Processes involving purified PDC have also been evaluated and it has been demonstrated that L-PAC levels up to 28 gl-1 can be obtained with yields of 90-95% theoretical based on the benzaldehyde added. In the review the advantages and disadvantages of the various strategies for the microbial and enzymatic production of L-PAC are compared. In view of the increasing interest in microbial biotransformations, L-PAC production provides an interesting example of enhancement through on-line control of a process involving both toxic substrate (benzaldehyde) and end-product (L-PAC, benzyl alcohol) inhibition.

Identification of a pyrovalerone metabolite in the rat by gas chromatography-mass spectrometry and determination of pyrovalerone by gas chromatography-nitrogen-phosphorus detection

Pyrovalerone and its hydroxylated metabolite have been identified by gas chromatography-mass spectrometry in rat urine and plasma. A sensitive gas chromatographic method for the quantitative analysis of pyrovalerone in rat urine and plasma is described. The method also permits the quantitative monitoring of the urinary excretion of the drug and its metabolite. Pyrovalerone and its hydroxylated metabolite are detected up to 18 h after a single oral administration to the rat at a dose of 20 mg/kg.

Detection and identification of pyrovalerone and its hydroxylated metabolite in the rat

Detection and identification of pyrovalerone and its metabolite, a hydroxylated product, are described. Their identities were confirmed by comparing their mass spectra and gas chromatographic retention times with those of the synthetic standards. The analytical method of pyrovalerone and its metabolite in biological samples was developed. The detection limit of the two compounds was 5 ng/mL, and the standard curves were linear in the concentration range of 10-5000 ng/mL. The single dose kinetics of pyrovalerone and the metabolite in rat urine and plasma were studied (n = 3). The calculated first half-life time of pyrovalerone in rat plasma was 0.34 h, and the second half-life time was 1.50 h. The half-life time of the metabolite was 0.39 h. The two products were detected in rat urine up to 18 h after a single oral administration and are suggested as screening target compounds in dope analysis.

Spectroscopic and elemental investigation of microbial decomposition of aquatic fulvic acid in biological process of drinking water treatment

As humic substances left in treated water tend to form trihalomethans during chlorination, their removal in water treatment processes is a significant concern for drinking water supplies. One of the removal technologies, the biofilm reactor is studied for the microbial decomposition of aquatic fulvic acid (AFA). The AFA is characterized by elemental analysis. UV-Vis, 13C-NMR, and IR spectroscopic methods. The spectroscopic and elemental investigation was capable of characterizing the microbial decomposition of AFA. Biologically treated fulvic acid was in a more oxidized state; its spectra displayed a higher degree of condensation of aromatic constituents than influent fulvic acid. Microbial degradation of AFA was more active in the low molecular weight fractions and intensively occurred in the aliphatic fraction.