Effects of anti-ulcer agents on ethanol-induced gastric mucosal lesions in D-galactosamine-induced hepatitis rats

Patients with hepatic injury have an increased incidence of gastric ulcers and erosions. In this study, the effect of D-galactosamine(GalN)-induced hepatitis on ethanol-induced gastric mucosal lesions and the protective effect of anti-ulcer agents in rats were examined. Subcutaneous injection of GalN (1 g/kg) remarkably increased serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities suggesting induction of hepatic injury. Gastric mucosal lesions induced by ethanol were significantly aggravated in GalN-induced hepatitis rats. Orally administered ecabet (CAS 86408-72-2; 20-200 mg/kg) dose dependently inhibited ethanol-induced gastric mucosal lesions in GalN-induced hepatitis rats. Sucralfate (CAS 54182-58-0) tended to inhibit the gastric mucosal lesions at a dose of 200 mg/kg but teprenone (CAS 6809-52-5), cimetidine (CAS 51481-61-9) and rebamipide (CAS 90098-04-7) had little effect. All anti-ulcer agents had no effect on the serum ALT and AST activities increased by GalN pretreatment. These results indicate that the gastric mucosa of GalN-induced hepatitis rats is more susceptible to injury induced by luminal irritants such as ethanol. Ecabet potently inhibited gastric mucosal lesions suggesting its clinical utility for the gastric mucosal damage in patients with hepatic injury.     

A major genotype in UDP-glucuronosyltransferase 2B15

A novel single nucleotide polymorphism (SNP) was found in exon 6 of the UDP-glucuronosyltransferase (UGT) 2B15 gene from healthy Japanese populations. The SNP was as follows: SNP, 020228Toide001; GENE NAME, UGT2B15; ACCESSION NUMBER, U08854, AF180322, and NM_001078; LENGTH, 25 base; 5'-AGCTTGCCAAAAC/AAGGAAAGAAGAA-3'. This SNP was expected to cause a change of an amino acid residue at the position 523 (Thr to Lys) located in a putative co-factor binding region. The allele frequency of this SNP was 79% in Japanese, suggesting this polymorphism to be a major genotype in Japanese people.     

Twenty one novel single nucleotide polymorphisms (SNPs) of the CYP2A6 gene in Japanese and Caucasians

We sequenced all nine exons and exon-intron junctions of the CYP2A6 gene from 33 Japanese and 28 Caucasians. We found twenty one single nucleotide polymorphisms (SNPs) including four SNPs causing amino acid substitutions, one silent SNP in exon 5, one SNP in a 5'-flanking region, four SNPs in a 3'-untranslated region, and eleven SNPs in introns. The four mutations (13G>A and 86G>A in exon 1, and 2134A>G and 2161C>T in exon 4) causing amino acid substitutions (Gly(5)Arg, Ser(29)Asn, Lys(194)Glu, and Arg(203)Ser), respectively, were as follows: SNP, 020719Kiyotani004; GENE NAME, CYP2A6; ACCESSION NUMBER, NG_000008.4; LENGTH, 25 base; 5'-ATGCTGGCCTCAG/AGGATGCTTCTGG-3'. SNP, 020719Kiyotani005; GENE NAME, CYP2A6; ACCESSION NUMBER, NG_000008.4; LENGTH, 25 base; 5'-AGCAGAGGAAGAG/ACAAGGGGAAGCT-3'. SNP, 020719Kiyotani011; GENE NAME, CYP2A6; ACCESSION NUMBER, NG_000008.4; LENGTH, 25 base; 5'-CGCTTTGACTATA/GAGGACAAAGAGT-3'. SNP, 020719Kiyotani012; GENE NAME, CYP2A6; ACCESSION NUMBER, NG_000008.4; LENGTH, 25 base; 5'-CTGTCACTGTTGC/TGCATGATGCTAG-3'. New alleles having these SNPs were designated as CYP2A6( *)13-CYP2A6( *)16.     

Effects of serum albumin and liver cytosol on CYP2C9- and CYP3A4-mediated drug metabolism

To investigate whether the free-drug theory is accurate in that only unbound drug is available for drug metabolism or enzyme inhibition. The effect of addition of rat liver cytosol to an in vitro system using human liver microsomes was examined by measuring the catalytic activities of CYP2C9 (tolbutamide and diclofenac) and CYP3A4 (terfenadine). And, the results were compared with those obtained when human serum albumin (HSA) was added to microsomes as far as unbound drug concentrations were concerned. After addition of rat liver cytosol, the unbound Km value (Km,u) for terfenadine metabolism by CYP3A4, and the unbound Ki value of miconazole (Ki,u) for CYP2C9 were smaller than for the controls. Addition of HSA resulted in smaller Km,u values for diclofenac and terfenadine metabolism by CYP2C9 and CYP3A4, respectively, and the Ki,u value for ketoconazole inhibition of CYP3A4 was also reduced. These results suggest protein-facilitated effects on drug metabolism and enzyme inhibition for both CYP2C9 and CYP3A4. However, no protein-facilitated drug metabolism was observed for tolbutamide in the presence of HSA or cytosol, or for diclofenac in the presence of cytosol. Protein-facilitated enzyme inhibition did not occur with miconazole in the presence of HSA or with ketoconazole in the presence of rat liver cytosol. Protein-facilitated metabolism and enzyme inhibition were observed for CYP2C9 and CYP3A4 in five cases but there was no obvious pattern of enzyme, substrate, or binding protein specificity. Further investigations are necessary to clarify the relevance of these results to in vivo observations.     

Accumulation of paralytic shellfish poisoning toxins in the edible shore crab Telmessus acutidens.

Several shellfishes including the crab Telmessus acutidens and its prey bivalve Mytilus galloprovincialis were collected at Onahama in Japan to investigate the accumulation of paralytic shellfish poisoning (PSP) toxins during the blooming season of toxic dinoflagellates. The toxicity of the viscera of T. acutidens collected in 1999 was 30.0 and 80.0 MU/g, and that of M. galloprovincialis was 9.6 MU/g by mouse bioassay. PSP toxins in the crab viscera were identified by HPLC-FLD and ESI-MS, so this is the first observation of PSP toxins in T. acutidens. Carbamate toxins (GTX1-4, and STX) were the major component in the crab as well as in the mussels, and accounted for over 60% on a molar basis. However, the ratio of the N1-OH toxin to N1-H toxin of the crabs were largely different from that of the mussels, and a reductive conversion of the toxins in T. acutidens is concluded as the probable cause. In 2000, PSP toxins were also detected in both crabs and mussels, though the contents were very low compared with the levels observed in 1999. The difference in the toxin abundance suggests that the toxin content in the crab was affected by those of the prey.     

Effect of conivaptan, a combined vasopressin V(1a) and V(2) receptor antagonist, on vasopressin-induced cardiac and haemodynamic changes in anaesthetised dogs.

The neurohormonal factor arginine vasopressin (AVP) produces potent systemic vasoconstriction as well as water retention in the kidneys via the V(1a) and V(2) receptors, respectively. Therefore, AVP may be considered as an aggravating factor of cardiac failure. In the present study, the effects of intravenous (i.v.) infusion of AVP on cardiovascular parameters and the effect of conivaptan (YM087, 4'-(2-methyl-1,4,5,6-tetrahydroimidazo[4,5-d][1]benzoazepine-6-carbonyl)-2-phenylbenzanilide monohydrochloride), a vasopressin V(1a)/V(2) receptor antagonist, on AVP-induced cardiac and haemodynamic changes were investigated in pentobarbitone-anaesthetised dogs. The i.v. infusion of AVP (0.12-4mUkg(-1)min(-1)) dose-dependently produced decreases in the cardiac contractility indicator LV dP/dt(max) and cardiac output (CO) and increases in left ventricular end-diastolic pressure (LVEDP) and total peripheral resistance (TPR). These changes accurately mimic the cardiovascular symptoms of congestive heart failure. The i.v. bolus injection of conivaptan (0.1mgkg(-1)) rapidly attenuated the AVP (4mUkg(-1)min(-1))-induced decrease in CO and reversed the AVP-induced elevation in both LVEDP and TPR. In conclusion, i.v. infusion of AVP produced cardiac dysfunction and vasoconstriction in pentobarbitone-anaesthetised dogs. Conivaptan demonstrated the ability to dramatically improve the impaired cardiovascular parameters induced by AVP. The results suggest the potential usefulness of conivaptan in treating congestive heart failure.     

Urinary cadmium excretion is correlated with calcaneal bone mass in Japanese women living in an urban area

Nine hundred eight women aged 40-88 years living in a non-Cd-polluted area in Japan were analyzed for urinary cadmium (Cd), N-acetyl-beta-D-glucosaminidase (NAG) activity, beta(2)-microglobulin (B2MG) concentration, and for the stiffness index (STIFF) of calcaneal bone using an ultrasound method. The urinary Cd in the subjects, with a mean and range of 2.87 and 0.25-11.4 microg/g creatinine, respectively, showed a significant correlation with NAG but not with B2MG. STIFF was significantly inversely correlated with urinary Cd, and the association remained significant after adjusting for age, body weight, and menstrual status, suggesting a significant effect of Cd on the bone loss in these subjects without signs of Cd-induced kidney damage. A two-fold increase in urinary Cd was accompanied by a decrease in STIFF corresponding to a 1.7-year rise in age. These results emphasize the need for reassessment of the significance of Cd exposure in the general Japanese population.     

Analysis of potential anti-aging beverage Pru,a traditional Cuban refreshment,by desorption electrospray ionization-mass spectrometry and FTICR tandem mass spectrometry

Aging has been established as a major risk factor for prevalent diseases and hence, the development of anti-aging medicines is of great importance. Recently, herbal fermented beverages have emerged as a promising source of potential anti-aging drug. Pru, a traditional Cuban refreshment produced by decoction and fermentation of multispecies plants with sugar, has been consumed for many years and is claimed to have multiple medicinal properties. Besides the traditional method, Pru is also manufactured industrially. The present study analyzed the major components of both traditional Pru (TP) and industrial Pru (IP) to reveal their potential application in promoting the health span. We performed desorption electrospray ionization-mass spectrometry (DESI-MS) and acquired mass spectra by scanning over the 50–1200 m/z range in both positive and negative ion modes. Fourier transform ion cyclotron resonance (FTICR) tandem mass spectrometry (MS/MS) was performed for validating the compound assignments. Three important compounds were identified by comparing the MS and MS/MS spectra with reported literature and the online database. One of the identified compounds, gluconic acid, was found to be the most abundant shared metabolite between TP and IP whereas the other two compounds, magnoflorine and levan were exclusively detected in TP. The present study is the first report of component profiling in Cuban traditional and industrial Pru using DESI-MS and FTICR MS/MS, and reveals the potential application of Pru as a health-promoting agent.