The influence of age and sex on the metabolism of tiaramide was studied in young (1 month), young-adult (2 months), middle-aged (12 months) and old (24 months) rats. Formation of the N-dealkylated metabolite by hepatic microsomes was highest in the young-adult males and decreased with aging. In the females, the formation was also maximal in the young-adults, became minimum in the middle-aged and reached the intermediate level in the old. Formation of the N-oxide metabolite by the microsomes was highest in the young-adult and middle-aged males and decreased with aging. In the females, the formation was low in the young-adults, increased to maximum in the middle-aged and decreased slightly from the maximal level in the old. The formation of two metabolites by the microsomes was higher in the young-adult and middle-aged males than in the corresponding females. Formation of tiaramide O-sulfate by hepatic 105, 000 g supernatants was maximal in the young males, decreased markedly in the young-adult and middle-aged males and increased again to the intermediate level in the old males. In the females, the sulfate formation by the supernatants was highest in the young-adults, decreased to minimum in the middle-aged, which was similar to the young, and increased again to the intermediate level in the old. The formation by the supernatants was higher in all females than males. Changes in urinary excretion of the metabolites exhibited age- and sex-related changes nearly similar to the formation by the rat liver. These results suggest that age- and sex-related changes in the hepatic metabolism of tiaramide reflect the changes in the urinary excretion of the metabolites in rats.
Abstract Combination therapy of tegafur/uracil (UFT) and leucovorin (LV) is widely used to treat colorectal cancers. Although this therapy has a significant therapeutic effect, severe adverse effects occur frequently. Therapeutic drug monitoring (TDM) may help to prevent adverse effects. A useful assay that can quantitate plasma levels of 5-FU, uracil, and tegafur simultaneously for TDM has been desired, but such a method is not currently available. In this study, we aimed to develop a sensitive method for simultaneous quantification of 5-FU, uracil, and tegafur in human plasma using ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). After preparing plasma samples by protein precipitation and liquid extraction, 5-FU, uracil, and tegafur were analyzed by UPLC-MS/MS in negative electrospray ionization mode. Validation was performed according to US Food and Drugs Administration guidance. The calibration curves were linear over concentration ranges of 2–500 ng/mL for 5-FU, 20–5000 ng/mL for uracil, and 200–50,000 ng/mL for tegafur. The corresponding average recovery rates were 79.9, 80.9, and 87.8%. The method provides accuracy within 11.6% and precision below 13.3% for all three analytes. Matrix effects of 5-FU, uracil, and tegafur were higher than 43.5, 84.9, and 100.2%, respectively. This assay was successfully applied to assess the time courses of plasma 5-FU, uracil, and tegafur concentrations in two patients with colorectal liver metastasis who received UFT/LV therapy after hepatectomy. In conclusion, we succeeded to develop a sensitive and robust UPLC-MS/MS method for simultaneous quantification of 5-FU, uracil, and tegafur in human plasma. This method is potentially useful for TDM in patients receiving UFT/LV combination therapy.
Radioactive 35S in 3'-phosphoadenosine 5'-phosphosulphate was incorporated into alicyclic, alkyl- and aryl- amines in the presence of hepatic 105 000 g supernatants of female rats. 4-Phenylpiperazine, 4-phenyl-1,2,3,6-tetrahydropyridine (PTHP), 1,2,3,4-tetrahydroisoquinoline, N-methylbenzylamine, desmethylzotepine and desmethylzimeldine showed the highest conjugation with 35SO3 among the amines tested. Incorporation of 35SO3 into alicyclic and alkyl-amines was higher at pH 10.0 than at pH 7.4 but the incorporation into arylamines was the opposite. A greater amount of 35SO3 was incorporated into the secondary alkylamines than the corresponding primary amines. Radioactive reaction products were identified as N-sulphoconjugates of amines by comparison on t.l.c. with synthetic authentic compounds. Reaction products of desmethylimipramine (DMI) and PTHP in vitro were isolated as their sulphoconjugates, identified by comparison of field desorption mass spectra, u.v. spectra, retention time on h.p.l.c. and RF values on t.l.c. with synthetic standards. DMI N-sulphonate and PTHP N-sulphonate were detected in the body of female rats treated orally with DMI and PTHP, respectively. These results indicate that N-sulphoconjugation is a common metabolic pathway of alicyclic, alkyl- and aryl-amines in vivo and in vitro.
Objectives This study aimed to clarify the relationship between the white blood cell (WBC) count and hypertension in the general Japanese population. Methods We conducted a population-based retrospective cohort study using annual health check-up data of residents of Iki City, Nagasaki Prefecture, Japan. A total of 2935 participants without hypertension at baseline were included in the present analysis. WBC counts were classified as tertile 1 (<4700/μL), tertile 2 (4700–5999/μL), and tertile 3 (≥6000/μL). The outcome was incident hypertension (blood pressure ≥140 mmHg). Multivariable-adjusted hazard ratios and 95% confidence intervals (95% CIs) were estimated using the Cox proportional hazards model. Result During an average follow-up of 4.5 years, 908 participants developed hypertension. The incidence (per 100 person-years) of hypertension increased with an elevation in the WBC count (6.3 in tertile 1, 7.0 in tertile 2, and 7.4 in tertile 3). This association was significant, even after adjustment for other risk factors, including age, sex, current smoking habits, current alcohol intake, exercise habits, obesity, elevated blood pressure, diabetes mellitus, and dyslipidemia. The hazard ratios were 1.07 for tertile 2 (95% CI 0.90–1.26) and 1.27 for tertile 3 (95% CI 1.06–1.51) compared with the reference group of tertile 1 (p = 0.009). Conclusion The WBC count was associated with future development of hypertension in the general Japanese population.
We developed an online continuous hemodiafiltration (CHDF) system with a central reverse osmosis (RO) fluid delivery system in 1996. This was improved to a system composed of a single-patient dialysis machine and RO module in 2003. This comprises a water treatment system, an RO module, a dialysis machine with 3 endotoxin retentive filters, 2 additional roller pump units, and a disposable special circuit. Dialysate is produced online by a dialysis machine using RO water and dialysate concentrate, which passes through endotoxin retentive filters and is supplied via the machine in the usual manner. A disposable special circuit and additional two roller pumps independently regulate dialysate flow and substitute flow from 0 to 12 in steps of 0.1 l/h. Seventy-seven patients with acute kidney injury (AKI) were treated with online CHDF from December 1996 to June 2004. Patient outcome was compared with the other modality of continuous renal replacement therapy from July 1992 to June 2004. The survival rates of each modality were 68.3, 65.0, 56.6 and 74.0% for conventional CHDF, high-flow continuous hemodialysis, high-flow CHDF and high-flow/high-volume CHDF (online CHDF), respectively. The survival rate of the high-volume modality (online CHDF) group was significantly higher (p = 0.046) than that of the low volume modality group (61.1%). Increases in efficacy and efficiency are a challenge facing blood purification therapy, and, moreover, individualized prescriptions are crucial in AKI patients in ICU. However, the cost of the dialysate and substitution fluid is a limitation of the therapy. The greatest advantage of the system is that a very high dose of delivered dialysate and substitute does not lead to a proportional rise in the cost. The online CHDF system is currently one of the most feasible solutions.
