No association of glutathione S-transferase M1 gene polymorphism with diabetic nephropathy in Japanese type 2 diabetic patients.

Oxidative stress possibly contributes to the development of diabetic nephropathy. Therefore, the levels of endogenous antioxidants may be one of determinants of the susceptibility to diabetic nephropathy. Glutathione S-transferases (GSTs) can work as one of endogenous antioxidants to protect cells from oxidative stress. The M1 member of GST mu class (GSTM1) is polymorphic and only expressed in 55-60% of Caucasians because of the homozygous deletion of the gene (null genotype). Recent studies have provided evidence that the GSTM1 null genotype, i.e. lack of the GSTM1 activity, is associated with an increased susceptibility to lung cancer and colorectal cancer. The present study was conducted to determine whether the genetic polymorphism influences the development of diabetic nephropathy. We examined 105 patients with diabetic nephropathy and 69 patients without diabetic nephropathy in Japanese type 2 diabetic patients with proliferative diabetic retinopathy. GSTM1 genotyping was performed by polymerase chain reaction. The two patient groups were well matched with regard to age, body mass index and HbAlc. GSTM1 null genotype was observed in 48.6% of patients with nephropathy versus 55.1% of patients without nephropathy. The frequency of GSTM1 null genotype was not significantly higher in the patient group with nephropathy than in the patient group without nephropathy. This study is the first to investigate the association of GSTM1 gene polymorphism with the development of diabetic nephropathy. The present results suggest that GSTM1 null genotype does not contribute to the development of diabetic nephropathy in Japanese type 2 diabetic patients.

[Effects of preoperative transcatheter arterial embolization (TAE) on the liver following partial hepatectomy in rats].

The safety of pre-operative transcatheter arterial embolization (TAE), especially on the relation to hepatic regeneration following partial hepatectomy, was evaluated in rats. TAE was done through a catheter cannulated into hepatic artery under laparotomy. The remarkable elevation of S-GOT and S-GPT levels were demonstrated a day after TAE, which returned to normal on third post operative day. No influence of the difference of embolized materials was seen on the changes of transaminase levels. TAE severely decreased hepatic microsomal functional mass measured by [14C]-aminopyrine breath test (ABT) and the recovery of microsomal functional mass was shown on the 14th day after TAE. Histologically, recanalization could not be revealed in embolized arterioles even on the 21st day after TAE. But trabecular pattern of hepatic lobules was preserved after TAE. The serious inhibition of DNA synthesis of regenerating liver was demonstrated when TAE was performed within 14 days prior to partial hepatectomy (p less than 0.001-0.05). The period from TAE to partial hepatectomy had a influence on the survival rate after partial hepatectomy, and when appropriate interval was taken after TAE, the survival rate increased significantly (33%-50% in 24 hours interval and 88% in 14 days interval). In conclusion, preoperative TAE remarkably suppressed hepatic regeneration after partial hepatectomy, and appropriate time when suppressed hepatic functional mass, such as microsomal functional mass measured by ABT, returned to pre TAE value was required to perform hepatectomy in safety.

[Studies on hyperthermia by the use of a thermosensitizing drug].

Hyperthermic treatment using ACNU combined with a thermosensitizing drug, methylglyoxal-bis-guanylhydrazone (MGBG), was studied in human gastric cancer xenotransplanted into nude mice. In order to increase the intra-cellular MGBG content, intraperitoneal injection of alpha-difluoromethylornithine(DFMO) 1000 mg/kg was performed twice with an interval of 6 hours and 50 mg/kg of MGBG was given at the time of the second administration of DFMO. After 6 hours of MGBG administration, ACNU 20 mg/kg was given intraperitoneally and, subsequently a 23-minute hyperthermia was carried out in a water bath at 43.5 degrees C. After 48 hours a second hyperthermia was performed by the same method. Tumor weight was estimated using Battelle's Columbus Institute protocol and the inoculated tumors, which were extirpated 60 minutes after 3H-thymidine injection at a prescribed interval after cessation of hyperthermia, were assayed biochemically for the determination of DNA biosynthesis. In mice given ACNU, DFMO, MGBG plus heat, considerably superior results were obtained. Although the DFMO plus MGBG group was inferior in antitumor activity to the ACNU only or heat only group, the DFMO, MGBG plus heat group showed much the same antitumor effects, compared to the ACNU plus heat group. These data suggest that the thermosensitizing efficacy of MGBG may be applicable for clinical use.

[Cyclic AMP- and ATP-mediated stimulation of DNA synthesis following partial hepatectomy by prostaglandin-E1 in D-galactosamine injured liver].

D-galactosamine (D-gal) damaged rats were infused with Prostaglandin E1 (PGE1) through a peripheral vein for 40 min. before and after partial hepatectomy. DNA synthesis following 68% partial hepatectomy was severely inhibited by the pretreatment of D-galactosamine. PGE1 infusion (0.5, 1.0 microgram/kg/min) enhanced the DNA synthesis inhibited by D-gal 600 mg/kg significantly (p less than 0.01). After 20 min. of PGE1 infusion cyclic AMP levels of liver tissue was increased as compared with saline infusion in D-gal (600 mg/kg)-damaged rat (p less than 0.05). Also 20 min. and 3 hour after partial hepatectomy. ATP levels of liver tissue was enhanced in PGE1 treated group (p less than 0.05). However the doses of PGE1 infused in this investigation could not increase the hepatic tissue blood flow measured by hydrogen gas clearance method. These results suggest that PGE1 enhance DNA synthesis of injured liver after partial hepatectomy by the mechanism which PGE1 stimulate cyclic AMP production and increase ATP level in hepatic tissue.

[Anticancer treatment with a combination of antimetabolites of polyamine and pyrimidine].

A combined efficacy of the polyamine antimetabolites, alpha-difluoromethylornithine (DFMO) and methylglyoxal-bis-guanylhydrazone (MGBG) with two fluorinated pyrimidines was studied. DFMO, MGBG, 5-FU and 5'-deoxy-5-fluorouridine (5'-DFUR) were administered intraperitoneally to BALB/c nu/nu mice bearing xenotransplanted human gastric cancer for 5 consecutive days. Similar antitumor efficacies were observed in 3 groups treated with DFMO plus MGBG, DFMO, MGBG plus 5-FU as well as DFMO, MGBG plus 5'-DFUR. The two groups on 5-FU or 5'-DFUR alone did not differ in antitumor effects from the control, although reasonable levels of 5-FU were involved in tumor tissues. Hepatic and splenic 5-FU levels after 5-FU administration were significantly higher than those after 5'-DFUR, and marked decrease in mouse body weight was caused by 5-FU alone as well as 5-FU plus polyamine antimetabolites for 5 consecutive days. DNA biosynthesis and spermine levels in the tumor tissues on day 2 after cessation of the treatments dropped in 3 groups with DFMO plus MGBG, DFMO, MGBG plus 5'-DFUR as well as DFMO, MGBG plus 5-FU, while on day 6 there was little difference between the control and treated groups. These data suggest that combination with 5-FU or 5'-DFUR does not enhance the antitumor activity of polyamine antimetabolites by this experimental regimen.

[Preoperative cancer chemotherapy for gastric cancer].

Preoperative cancer chemotherapy for gastric cancer was reviewed with special emphasis on histologic findings and survival. Preoperative chemotherapy with intravenous, split administration of MMC 40 mg caused considerable damage to "micro-solitary metastatic foci" in metastatic lymph nodes. In view of the lipid-adsorbing ability of the lymphatic stream, emulsified 5-FU was used orally in 182 patients with gastric cancer; histologic findings revealed that the emulsified 5-FU enhanced the antitumor efficacy for metastatic lymph nodes as well as the primary lesion. However, the 5-year survival rate for gastric cancer patients undergoing preoperative emulsified 5-FU therapy did not differ from the control, with only the exception of patients with Stage III gastric cancer. On the other hand, combined therapy involving preoperative intra-arterial infusion and surgery was carried out in 62 patients with gastric cancer. These preoperative treatments using MMC, 5-FU, VLB, MTX and/or cytosine arabinoside entailed continuous infusion for 15 to 20 hours; the histologic changes observed revealed marked antitumor effects on the primary focus as well as metastatic lymph nodes. The five-year survival rate for the 62 patients was compared with that for 99 patients with gastric cancer in the corresponding period. The survival rate was analyzed based on the degree of serosal invasion. The overall survivals in the 62 patients were higher than those in the controls for the first 3 years. At 4 to 5 years, the survival rates for both the treated and control groups were approximately equal. In patients without serosal invasion, the survival rates were higher in treated cases than in the controls for the first 2 years. Thirty-nine patients with serosal invasion had significantly higher survival rates than the controls for the first 3 years. The survival rates for the treated patients with cancerous infiltration of ther organs were about the same as those for the corresponding control patients.

[Experimental hyperthermo-chemotherapy for human gastric carcinoma transplanted in the nude mice].

Human gastric carcinomas serially xenotransplanted into BALB/c nu/nu mice were treated by hyperthermo-chemotherapy with mitomycin C (MMC). The antitumor efficacy was assessed by both single and double treatments of 25-minute hyperthermia (43.5 degrees C) and/or 2.0 mg/kg of MMC (ip). Tumor weight was estimated using Battelle's Columbus Laboratories protocol. To assess DNA biosynthesis in the tumor cells, the xenotransplanted tumors were excised at prescribed times after these treatments 60 minutes after 3H-thymidine injection (ip), and were examined microscopically. In the group treated twice by hyperthermo-chemotherapy marked growth inhibition and microscopic damage of the tumors were observed, while such features were not recorded in groups treated twice by hyperthermia only and chemotherapy only, nor in groups given single hyperthermo-chemotherapy, or hyperhermia and chemotherapy. In the single-treated groups, DNA biosynthesis was remarkably inhibited by hyperthermo-chemotherapy over 24 hours. The present results suggest that repeated treatments of hyperthermo-chemotherapy with MMC may be effective in the treatment of human gastrointestinal cancer.

[Experimental studies on hepatic cancer chemo-embolization].

Mitomycin microspheres (MMC MS), which contain about 5% of MMC and have an average diameter of 45 +/- 8 microns, were administered into the rat hepatic artery in a preclinical study on antitumor treatment for human hepatic cancer. Plasma GOT and GPT activities increased markedly 24 hours after MMC MS injection; they decreased to within the normal range within 3 days of the injection. Hepatic necrobiosis was observed in the area adjacent to the hepatic arterioles containing MMC MS, but was not observed in rats injected with placebo microspheres. The hepatic vein blood of MMC MS treated rats contained a markedly high level of MMC, compared to rats treated in the conventional fashion with MMC. Furthermore, MMC MS remained within hepatic arterioles for over 3 weeks.

[Combined therapy with polyamine biosynthesis inhibitors and mitomycin C].

An attempt was made to analyse tumor growth after cessation of combined therapy with the polyamine biosynthesis inhibitors, alpha-difluoromethylornithine (DFMO) and methylglyoxal-bis-guanylhydrazone (MGBG), as well as mitomycin C (MMC). DFMO 1000 mg/kg, MGBG 50 mg/kg and/or MMC 2 mg/kg were given intraperitoneally to BALB/c nu/nu mice xenotransplanted human gastric cancer, and its growth as well as DNA biosynthesis were measured daily, after cessation of these combined treatments. Histological observation of the tumor was also performed by hematoxylin-eosin staining. The combination with DFMO and MGBG stunted tumor growth during the treatment, but 3 days later its growth and DNA biosynthesis were accelerated distinctly. MMC injection halted tumor growth, and 5 days after termination of MMC injection its growth rate and DNA biosynthesis almost completely recovered. The microscopic findings on the 4th day after termination of MMC injection were similar to those of DFMO + MGBG treatment. The combination DFMO, MGBG and MMC suppressed not only tumor growth during the treatment, but also tumor growth and DNA biosynthesis over 7 days. The histologic observation 4 days later revealed extensive damage.

[Preclinical studies of intra-arterial chemotherapy using mitomycin C microspheres].

Heated albumin microspheres 45 +/- 8 microns dia. containing 5% mitomycin C were infused into rabbit femoral artery to assess the depot effects. MMC levels were measured in the muscle and VX -2 tumor tissues fed by the femoral artery as well as in the drainage vein blood. Furthermore, the histologic changes in the VX -2 tumor and the MMC microspheres entrapped in the arterioles were surveyed microscopically. Drug concentration in the case of MMC microspheres was maintained at high levels in both tissue and venous blood over 4 hours, but in the rabbits infused conventional MMC, drug levels decreased below the assay limitation 2 hours after injection. The microscopic findings 2 weeks later revealed necrotic VX -2 tumor tissue as well as the MMC microspheres remaining in the arterioles .

[Combined antitumor therapy with polyamine biosynthesis inhibitors and mitomycin C].

A combined effect of the polyamine biosynthesis inhibitors, alpha-difluoromethylornithine (DFMO) and methyglyoxal-bis-guanylhydrazone (MGBG) with mitomycin C (MMC) was studied. DFMO, MGBG and MMC were given intraperitoneally to nude mice xenotransplanted human gastric cancer. This new combination of the three drugs resulted in the complete halt of the xenotransplanted tumor growth and marked decline of spermine levels in the tumor tissues. The other treatments with DFMO and MGBG as well as MMC alone were inferior to this new combined therapy in suppression in both tumor growth and tissue spermine level. These data suggest that this new combined treatment be effective against human gastric cancer.