Influence of carboxylesterase 2 genetic polymorphisms on mycophenolic acid pharmacokinetics in Japanese renal transplant recipients.

Mycophenolic acid (MPA), converted from the prodrug mycophenolate mofetil (MMF), is generated by intestinal and hepatic esterases. The role of carboxylesterase (CES) in MMF hydrolysis was examined in vitro using human liver microsomes. V(max) and K(m) values of MMF hydrolysis in pooled human liver microsomes were 1368 +/- 44 nmol min(-1) mg(-1) protein and 1030 +/- 65 microM, respectively. Hydrolytic activity was inhibited by the CES inhibitors phenylmethylsulfonylfluoride, bis-p-nitorophenylphosphate and diisopropylfluorophosphate, with IC(50) values of 77.1, 3.59 and 0.0312 microM, respectively. Eighty Japanese renal transplant recipients that received repeated-doses of MMF, tacrolimus and prednisolone,were evaluated for MPA pharmacokinetics 28 days after transplantation to investigate the relationship between MPA pharmacokinetics and CES2 genetic polymorphisms. No significant differences in MPA pharmacokinetics were observed between CES2 A4595G, C8721T orA-1548G genotype groups. CES2 allelic variants also did not appear to affect plasma MPA concentrations between individuals. In conclusion, the study demonstrated that while CES1 and/or CES2 are involved in the hydrolysis of MMF to MPA, CES2 allelic variants appeared to make only a minor contribution to inter-personal differences in MPA pharmacokinetics.

Nafamostat is hydrolysed by human liver cytosolic long-chain acyl-CoA hydrolase.

Although the authors recently reported that nafamostat, a clinically used serine protease inhibitor, was mainly hydrolysed by carboxylesterase in human liver microsomes, the involvement of human liver cytosol has not been elucidated. The current study examined the in vitro metabolism of nafamostat with human liver cytosols. Kinetic analysis indicated that the Vmax and Km values in the liver cytosols were 9.82 nmolmin(-1) mg(-1) protein and 197 microM for a liver sample HL-1, and 15.1 nmolmin(-1) mg(-1) protein and 157 microM for HL-2, respectively. The Vmax/Km values in both cytosols were at least threefold higher than those in the corresponding microsomes. The liver cytosolic activity for nafamostat hydrolysis was inhibited by phenylmethylsulfonyl fluoride (PMSF) (43% inhibition at 100 microM), whereas diisopropyl fluorophosphate (DFP) and bis(p-nitrophenyl)phosphate (BNPP) failed to inhibit the activity. Furthermore, the hydrolytic activity was also reduced by palmitoyl-CoA (67% inhibition at 100 microM) but not by acetyl-CoA. Effects of PMSF, DFP and BNPP on cytosolic palmitoyl-CoA hydrolytic activity were comparable with those of the cytosolic nafamostat hydrolytic activity. In addition, the palmitoyl-CoA hydrolytic activity was competitively inhibited by nafamostat with the apparent Ki value of 164 microM for the liver cytosol from HL-2. These results suggest that an isoform of long-chain acyl-CoA hydrolase may be responsible for the nafamostat hydrolysis in human liver cytosol.

Genetic architecture for normal and novel host-plant use in two local populations of the herbivorous ladybird beetle, Epilachna pustulosa.

Trade-offs in host-plant use are thought to promote the evolution of host specificity. However, usually either positive or no genetic correlations have been found. Whereas factors enhancing variation in overall viability have been claimed to mask negative genetic correlations, alternative hypotheses emphasize the sequential changes in genetic correlation in the course of host-range evolution. In this study, the genetic architectures of performances on different hosts were compared in two populations of the herbivorous ladybird beetle, Epilachna pustulosa, using three host plants, one being normal for both, one novel for only one population, and the other novel for both populations. The genetic correlations between larval periods on normal hosts were significantly positive whereas those between normal and novel hosts were not different from zero. There was no evidence for reduced genetic variation on the normal host-plants. These results suggest that the host-range is not restricted by the antagonistic genetic associations among exploitation abilities on different plant species, but rather that selection of different host-plants may improve the coordination between genes responsible for the use of different plants.

Comparison of genetic variation in growth performance on normal and novel host plants in a local population of a herbivorous ladybird beetle, Epilachna vigintioctomaculata.

Local populations of herbivore species that display variation in host plant use are subject to natural selection for improved ability to use their own host species. Since natural selection changes the frequency of alleles that control host use, genetic variation in growth performance on host plants may change with each generation of selection. Therefore, within-population variations in the ability to use different hosts may reflect past selective forces. The present study reports the genetic variation in growth performance in a population of the herbivorous ladybird beetle, Epilachna vigintioctomaculata Motschulsky (Coccinellidae, Epilachninae) on both the normal host and a novel host. The present study found higher heritabilities for growth performance on the novel host than the normal host. The difference in heritabilities was caused by smaller among-family variance components on the normal host compared to those on the novel host. The results are compatible with the view that natural selection, which improved the ability of the population to use a particular host plant, has reduced genetic variation within that population in the ability to use that host plant. The pattern of reduced genetic variation in a population reared on the normal host observed in the present study is compared with that in another population, which showed local adaptation in the use of its own host plant. The effect of natural selection on differing host plant use on within-population genetic variation is discussed.

Local therapy of carcinoma of the uterine cervix: part I.

One-hundred-fifteen patients with cervical cancer were treated by placing bleomycin, carbazilquinone (Carboquone), and 5-fluorouracil suppositories in contact with cancer lesions located in the vaginal portion of the uterus or by inserting them into the cervical canal, twice a week, one to 14 times. The cancer lesions disappeared form 17 to 33 patients with Stage 0 lesions and 9 of 42 with Stage IA lesions. The remaining lesions were principally found in the deep portion of the cervical glands and tended to decrease the more often the suppositories were applied. This led to the presumption that if this local therapy had been carried on longer it would have eradicated even the remaining lesions from the patients with Stage 0 and IA lesions. The optimal per administration dose of bleomycin appeared to be 30 mg. The use of Witepsol (Dynamit Nobel Aktiengesellschaft, F.R.G.) suppository base was accompanied by frequent adverse reactions to it, which hindered the local therapy from being repeated over long periods of time. An equal amount mixture of hydroxypropyl cellulose and carbomer (Carbopol 934) as the suppository base was accompanied by relatively less adverse reactions, which permitted the prolonged local therapy with the suppositories. A trace of bleomycin was also found in the ovaries, but it did not cause microscopically evident histologic changes, nor did it affect the menstrual cycle. If early cancer can be treated completely by local therapy, it will be useful for the younger patient with early cervical cancer.

Erythropoietin levels in the course of a patient with erythropoietin-producing renal cell carcinoma and transplantation of this tumor in nude mice.

Erythropoietin was measured by exhypoxic polycythemic mouse method in the course of a 64-yr-old male with renal cell carcinoma associated with erythrocytosis. Serum erythropoietin fluctuated with progression of the disease. Preoperative elevated erythropoietin (0.11 U/ml, p greater than 0.05) subsided after nephrectomy and again increased with developing lung metastasis (0.1 U/ml, p greater than 0.02). Erythropoietin was markedly increased in the tumorous extracts from primary renal cell carcinoma in the kidney (0.2 U/g, p greater than 0.01) and lung metastasis (0.8 U/g, p greater than 0.01). Renal cell carcinoma from the lung metastasis was transplanted into nude mice, resulting in erythrocytosis in some of these mic. In the erythrocytotic mice, erythropoietin was elevated to levels of 0.25--0.9 U/g (p greater than 0.01) in the tumorous extracts and increased (0.67 U/ml, p greater than 0.02) in the serum. These results indicate that this renal cell carcinoma is an erythropoietin-producing tumor, and this tumor has been successfully transplanted in nude mice for the first time.