Clinical basis of chemotherapy for gastric cancer with uracil and 1-(2'-tetrahydrofuryl)-5-fluorouracil

Studies were performed on the clinical basis of chemotherapy for human cancer with uracil and 1-(2'-tetrahydrofuryl)-5-fluorouracil (FT). In 62 operated patients with stomach, breast, and uterine cancers, the concentration of 5FU and FT were compared in serum, tumor and normal tissues 1, 2, 4, 6, 8, and 12 hours following the administration of 300 mg of UFT (300 mg of FT plus 672 mg uracil, a uracil/FT molar ratio of 4), or FT alone. It was found that the level of 5-FU in tumor tissue remained above 0.05 mcg/g over 12 hours. This value for 5-FU corresponds to a minimum inhibitory concentration in the Vitro experiment with L1210 cells. BLood levels of 5-FU increased up to 0.1 mcg/ml 1 hour after UFT administration and then decreased below 0.05 mcg/ml. The drug concentration in normal tissues was lower than that of the tumor tissues. On the basis of the above findings and phase I study, a protocol of UFT-therapy was made and applied for the treatment of gastric cancer. Our patients were given an oral dose of 300 mg of UFT twice a day per 50 kg body weight (12 mg/kg BW). Therapeutic effects were detectable in 7 of 20 cases. In addition, a combination of mitomycin C (6 mg i.v. weekly) with UFT seemed to improve the response rate (5/7). Diarrhea (15%) and skin pigmentation (10%) were major side effects of UFT.     

Levels of vitamin K, immunoreactive prothrombin, des-γ-carboxy prothrombin and γ-glutamyl carboxylase activity in hepatocellular carcinoma tissue

Abstract To clarify the mechanism of production of des-γ-carboxy (abnormal) prothrombin (DCP) by hepatocellular carcinoma (HCC), we measured the levels of vitamin K, DCP, immunoreactive prothrombin and the activity of γ-glutamyl carboxylase in liver tissues from HCC patients and in the medium of cultured human hepatoma cells. There was no significant difference in vitamin K (K₁, MK-4) contents between HCC and non-HCC cirrhotic liver tissues. The activity of γ-glutamyl carboxylase per unit amount of endogenous microsomal prothrombin precursor was decreased in HCC tissue compared with non-HCC liver tissue (positive plasma DCP: 335 ± 72 vs 372 ± 67, negative plasma DCP: 370 ± 84 vs 393 ± 56 nmol/min per mg prothrombin precursor, P > 0.05), although the total incorporation of ¹⁴COOH into microsomal precursor protein was higher in the former. By contrast, levels of DCP and immunoreactive prothrombin in HCC tissue were greater ( P > 0.05) than those in non-HCC cirrhotic liver tissue. Furthermore, production of large amounts of immunoreactive prothrombin was observed in human hepatoma cells huH-1 and huH-2, which produced large amounts of DCP. These results suggest that there was excessive synthesis of prothrombin precursors by human HCC tissue and hepatoma cell lines huH-1 and huH-2. Thus, excessive synthesis of prothrombin precursors seems to be the main mechanism of DCP production by HCC.     

Intratumoral injection of thymidine: enhancement of the antitumor activity and incorporation of 5-fluorouracil into tumor RNA in a murine tumor system

Intratumoral injection of thymidine (dThd) into mice bearing an Ehrlich ascites solid tumor in combination with an ip injection of 5-fluorouracil (FUra) was performed to investigate the following: (a) whether intratumoral injection of dThd would increase both the incorporation of FUra into tumor RNA and the antitumor activity of FUra as effectively as ip injection of dThd, and (b) whether intratumoral injection of dThd would have a selective advantage for increasing the incorporation of FUra into the tumor RNA, relative to normal tissue RNA. Pulse-labeling with [3H]FUra at different times after dThd injection indicated that the most effective incorporation of FUra into the tumor RNA occurred with both intratumoral and ip injection of dThd, when FUra and dThd were given simultaneously. The amount of FUra-containing RNA [(FU)RNA] was dThd dose-dependent and reached a maximum at a dThd dose of 100 mg/kg, in the case of either intratumoral or ip injection. The maximal level with intratumoral injection of dThd was twofold higher than the level with ip injection and at least fivefold higher than the level achieved with FUra alone. In a time course study, the amount of (FU)RNA formed after intratumoral injection of dThd was comparable to the level obtained with ip injection, which was fourfold to sixfold greater than that seen with FUra alone. Furthermore, in the four normal organs (bone marrow, intestine, kidneys, and lungs) the amount of (FU)RNA formed after intratumoral injection of dThd was markedly lower than the level with ip injection. Assay of FUra degradation products revealed low levels of FUra catabolism in the tumor tissue compared to liver. In addition, therapy experiments showed that the antitumor activity of FUra was increased 17-fold by coadministration of dThd by either route.     

Rational basis for the metabolic modulation of 5-fluorouracil by leucovorin and interferon alpha

Although 5-fluorouracil (FUra) has been the drug of choice for the treatment of patients with advanced colorectal carcinoma, the response rates are in the range of 15% and the median survival times do not exceed 9 months. Interferon alpha (IFNα) has limited antitumour activity in this disease. Recent clinical trials have demonstrated that both the response rate and the survival time of patients with advanced colorectal cancer can be significantly improved by the addition of leucovorin (CF) to FUra. In a randomized phase III trial, the median response to FUra and CF was about 30% with a range of 20–55%, dependent on the dose and schedule of administration of CF. Due to multiplicity of mechanisms of action postulated for IFNα, the role of IFNα in the modulation of the cytotoxicity and therapeutic efficacy of FUra alone and in combination with CF has been evaluated in patients with advanced colorectal cancer and also in a variety of human cell lines in culture, including human colorectal cell lines, HCT-8, human bladder cell line RT-4 and leukaemia CEM cells.
The results obtained in patients demonstrated that indeed the antitumour activity of FUra can be improved by the addition of IFNα with a response range from 26% to 76%. The initial clinical use of this combination, however, has been limited in some cases by the severe host toxicity. In vitro results demonstrated that: (1) in vitro cytotoxicity potentiation by IFNα is cell-type dependent; (2) in these cells where modulation was possible, αIFN was used as a low and noncytotoxic doses (10–50 μg/ml for 3–5 d exposure), and (3) the cytotoxicity of IFNα was dose dependent, indicating a direct antiproliferative cellular effect.     

Efficacy of hepatic arterial infusion therapy for advanced hepatocellular carcinoma using 5-fluorouracil, epirubicin and mitomycin-C]

BACKGROUND/AIM: Prognosis of advanced hepatocellular carcinoma (HCC) treated by conventional therapies has been considered to be poor. The aim of this study was to evaluate the efficacy of hepatic arterial infusion therapy (HAIT) using FEM (5-fluorouracil, epirubicin, mitomycin-C) regimen for advanced HCC. METHODS: Eighteen patients received repeated HAIT using an implanted drug delivery system. Of the 18 patients, 8 patients had HCC with portal vein tumor thrombosis, 9 patients had recurrent HCC after transarterial chemoembolization (TACE) and 1 patient after surgical resection. The patients received 5-fluorouracil (330 mg/m(2), every week), epirubicin (30 mg/m(2), every 4 weeks) and mitomycin-C (2.7 mg/m(2), every 2 weeks). RESULTS: Mean age was 51 years. The response rate (complete response+partial response) by tumor size on abdominal CT was 38.9%. Survival ranged from 2 to 24 months and the median survival time was 8 months. The cumulative survival rate of responders group was significantly higher than non-responders group (p=0.0385). The mean levels of serum alpha-FP and PIVKA-II in responders group decreased after HAIT (3,179 ng/mL and 2,850 ng/mL) than before (11,218 ng/mL and 4,396 ng/mL), but not significantly. Chemotherapy-related side effects were nausea, vomiting and alopecia. Three patients had catheter-related complications. One patient developed gastric ulcer. CONCLUSIONS: HAIT using FEM regimen is a useful therapeutic option for patients with advanced HCC with portal vein tumor thrombosis or ineffective response to other therapies.     

Interleukin-2 as a modulator of 5-fluorouracil in hepatic arterial immunochemotherapy for liver metastases

BACKGROUND/AIMS: Hepatic arterial infusion of interleukin-2-based immunochemotherapy has yielded a high response rate (> 75%) in patients with unresectable liver metastases. In order to clarify the mechanisms that underlie the apparent benefit of combination treatment, the role of IL-2 as a modulator of 5-fluorouracil metabolism was investigated. METHODOLOGY: A single dose of 5-fluorouracil (50 mg/kg) with or without IL-2 (3500 Japan Reference Units/kg) was given via the hepatic artery to rats bearing liver metastases. Thirty minutes later samples of liver metastatic foci or surrounding normal liver tissue were removed for the measurement of thymidylate synthase, thymidine kinase and dihydropyrimidine dehydrogenase activity, and 5-fluorouracil content. RESULTS: 5-fluorouracil levels in tumor were significantly higher than in normal liver. Although the addition of IL-2 reduced 5-fluorouracil levels in both tumor and normal liver tissues by the activation of dihydropyrimidine dehydrogenase, the ratio of tumor/normal liver 5-fluorouracil levels was unchanged. Both thymidylate synthase and thymidine kinase activities were significantly inhibited in tumor tissue when the combination of 5-fluorouracil and IL-2 was administered. CONCLUSIONS: IL-2 increases 5-fluorouracil cytotoxicity through the inhibition of thymidylate synthase/thymidine kinase activities in the hepatic arterial infusion.     

Activity and safety of pegylated liposomal doxorubicin,5-fluorouracil and folinic acid in inoperable hepatocellular carcinoma: A phase Ⅱ study

AIM: To improve the results of New therapeutic strategies in hepatocellular carcinoma (HCC). We have conducted a phase Ⅱ study with pegylated liposomal doxorubicin (PLD), 5-fluorouracil (5FU) and folinic acid (FA).METHODS: Thirty-one patients with hystologically-confirmed, inoperable HCC, received combination chemotherapy with PLD 25 mg/mq on d 1, 5FU 1200 mg/mq in 48 h continuous infusion, and oral FA 30 mg on d 1 and 2 every 3 wk until disease progression or intolerable toxicity.RESULTS: The median age was 65 years (range 41-82) and 28 patients were hepatitis C virus seropositive (90%).The majority of patients were Child-Pugh Class B (55%).Two patients showed a partial response (PR), and 16 had stable disease (SD). With a median follow-up of 14 mo, the median time to progression of all evaluable patients was 4 mo (95% CI 1.7-7). Median overall survival was 9 mo (95% CI 3-24 mo). After 1 year, 9 of 18 PR/SD patients were alive. Chemotherapy was well tolerated.CONCLUSION: PLD/FU/FA combination seems capable of achieving durable stabilization of HCC. The manageable toxicity supports a role for combination with other anticancer agents.     

Coproporphyrinogen oxidase, protoporphyrinogen oxidase and ferrochelatase activities in human liver biopsies with special reference to alcoholic liver disease

The activities of coproporphyrinogen oxidase, protoporphyrinogen oxidase and ferrochelatase have been assayed in human liver biopsies using recently developed highly sensitive specific enzyme assays. The specific activities (nmol/min/mg protein) in controls were 0.010 +/- 0.003 (mean +/- S.D., n = 11), 0.18 +/- 0.07 (n = 9) and 0.062 +/- 0.022 (n = 8), respectively. The total activities (mumol/min/liver) were determined, using ultrasound to determine liver volumes, and were 2.6 +/- 0.6 (n = 5), 36.6 +/- 13.9 (n = 6) and 14.2 +/- 5.4 (n = 3), respectively. Both specific and total enzyme activities in alcoholics with fatty liver were not significantly different from normal controls. Decreased protoporphyrinogen oxidase activity (0.08 nmol/min/mg protein or 20.2 mumol/min/liver) was found in two patients with variegate porphyria. In a patient with erythrohepatic protoporphyria a reduction of the ferrochelatase activity (0.01 nmol/min/mg protein) was demonstrated.     

Fatty acid oxidation by skeletal muscle homogenates from morbidly obese black and white American women

The purpose of this study was to determine if there were differences in the capacity of skeletal muscle from morbidly obese Black and White American women to oxidize fatty acids. The oxidation rates of (14)C-palmitate, (14)C-palmitoyl-CoA, and (14)C-palmitoyl-carnitine were measured in whole homogenates of rectus abdominus from Black and White women who were similar in age and body mass index (BMI). The activities of muscle citrate synthase (CS), beta-hydroxy acyl-CoA dehydrogenase (beta-HAD), and mitochondrial and microsomal acyl-CoA synthetase (ACS) were measured in the 2 groups. The results showed that the rate of (14)C-palmitate oxidation by muscle of Black women was 25% that of Whites (8.7 +/- 1.5 v 34.4 +/- 6.8 nmol (14)CO(2) produced/gram tissue wet weight/ hour; P <.05), but the rates of (14)C-palmitoyl-CoA and (14)C-palmitoyl-carnitine oxidation were not different in the 2 groups. No differences were found in the activities of CS or beta-HAD. However, the activities of both mitochondrial and microsomal ACS were lower in the Black women than the Whites (mitochondrial ACS 25.1 +/- 3.9 v 36.4 +/- 5.0 nmol/mg protein/min; P <.05; microsomal ACS 6.2 +/- 0.5 v 8.5 +/- 0.5; nmol/mg protein/min; P <.005). The lower rate of palmitate oxidation, and the lack of differences in the rates of palmitoyl-CoA and palmitoyl-carnitine oxidation indicate that there is a defect in the activation of the fatty acid in the muscle of the Black women. This was confirmed by the decrease in mitochondrial ACS activity in the Black women. The decreased fatty acid oxidation by skeletal muscle of obese Black women could result in shunting these fuels from muscle to adipose tissue for storage, which may contribute to the maintenance of obesity in the Black women.     

Activity and safety of pegylated liposomal doxorubicin, 5-fluorouracil and folinic acid in inoperable hepatocellular carcinoma： A phase Ⅱ study

AIM: To improve the results of New therapeutic strategies in hepatocellular carcinoma (HCC). We have conducted a phase Ⅱ study with pegylated liposomal doxorubicin (PLD), 5-fluorouracil (5FU) and folinic acid (FA). METHODS: Thirty-one patients with hystologically- confirmed, inoperable HCC, received combination chemotherapy with PLD 25 mg/mq on d 1, 5FU 1200 mg/mq in 48 h continuous infusion, and oral FA 30 mg on d 1 and 2 every 3 wk until disease progression or intolerable toxicity. RESULTS: The median age was 65 years (range 41-82) and 28 patients were hepatitis C virus seropositive (90%). The majority of patients were Child-Pugh Class B (55%). Two patients showed a partial response (PR), and 16 had stable disease (SD). With a median follow-up of 14 mo, the median time to progression of all evaluable patients was 4 mo (95% CI 1.7-7). Median overall survival was 9 mo (95% CI 3-24 mo). After 1 year, 9 of 18 PR/SD patients were alive. Chemotherapy was well tolerated. CONCLUSION: PLD/FU/FA combination seems capable of achieving durable stabilization of HCC. The manageable toxicity supports a role for combination with other anticancer agents.     

Hepatic arterial infusion of 5-fluorouracil in combination with subcutaneous interferon-alpha for advanced hepatocellular carcinoma

BACKGROUND/AIMS: Transcatheter arterial chemoinfusion (TACI) is the main therapeutic modality for advanced hepatocellular carcinoma (HCC) with portal thrombus. However, TACI is not sufficient to improve prognosis. In this study, we evaluated the response to hepatic arterial infusion of 5-fluorouracil (5-FU) in combination with subcutaneous interferon (IFN)-alpha in patients with advanced HCC. METHODOLOGY: Ten patients (men, 8; women, 2; mean age, 55-77) with advanced HCC were enrolled in this study. Hepatic arterial infusion of 5-FU (500 mg/24 hrs) was performed for 5 days on the first and second week. IFN-alpha (5 x 10(6) International Units) was subcutaneously administered three times a week for 4 weeks (1 therapeutic course). Response to therapy was evaluated by abdominal computed tomography at the end of two courses of therapy. Results: Seven patients received more than two courses of therapy. One patient (14%) showed complete response (CR). Four patients had stable disease (SD) (57%) and the remaining 2 patients had progressive disease (PD) (29%). Tumor markers decreased in all patients except 1 with PD. The 6-month survival rate was 40%. Therapy was discontinued in 3 patients due to severe adverse effects; all of these patients were over 70 years old, and had moderate liver dysfunction (Child-Pugh score of Grade B) before initiation of therapy. CONCLUSIONS: The goal of the therapy with hepatic arterial infusion of 5-FU in combination with subcutaneous IFN-alpha was attained in only 14% among our advanced HCC patients. The tumor completely disappeared in 1 patient, suggesting that this therapeutic modality may be of potential benefit in advanced HCC patients. However, this therapy should be performed with caution in patients with poor hepatic function (grade B or C of Child-Pugh score) and in those more than 70 years old.     

Improving the anti-tumor activity of 5-fluorouracil by increasing its incorporation into RNA via metabolic modulation.

The experiments described here illustrate the use of metabolic modulation to improve the therapeutic effectiveness of 5-fluorouracil (5FUra) in two murine tumor systems (CD8F1 mannary carcinoma and CD2F1 colon tumor 26). The manipulations chosen were based on the assumption that a major fraction of the anti-tumor activity of 5FUra is due to its incorporation into RNA and that the resulting 5FUra-RNA creates difficulty for a variety of cellular mechanisms requiring RNA processing and function. This hypothesis leads to the prediction that thymidine would promote the anti-neoplastic effect of 5FUra due to the following possible interactions: (i) sparing 5FUra from catabolic degradation by saturating the relevant enzymes wit thymidine; (ii) selective arrest of normal cells due to feedback inhibition of robonucleotide reductase by the accumulating thymidine triphosphate (TTP); and (iii) the high levels of TTP would also be expected to repress the anabolic conversion of 5FUra to the deoxy derivatives, thus preserving it for entry into RNA. The data show that thymidine (and certain other nucleosides) does in fact markedly stimulate the incorporation of 5FUra into nuclear RNA and that this event is paralleled by a striking icrease in anti-tumor activity. Kinetic analysis reveals that, although the injection of 5FUra leads to an immediate cessation of thymidylate synthetase activity, DNA synthesis continues at a lower rate for 12 hr and then ceases completely. At this point, in contrast to the earlier partial inhibition, the addition of thymidine fails to restore the ability of the tumor cells to synthesize DNA.     

Studies on long chain fatty acid:CoA ligase from human small intestine.

Long chain fatty acid:CoA ligase (EC 6.2.1.3.) was examined in human small intestinal mucosa using the hydroxamate-trapping method. With optimal assay requirements using palmitate as substrate a significant difference of specific activities could be detected in the total homogenate from duodenum, 40.9 +/- 11.6 nmol/min per mg protein versus upper jejunum, 51.9 +/- 13.7 (P less than 0.05). The enzyme activity of the microsomal fraction of upper jejunum was 101.8 +/- 44 nmol/min per mg protein. ATP, CoA, and Mg2+ were essential constituents of the reaction. A broad pH-optimum was observed between 6.75 and 7.75 with a maximum at a pH of 7.25. Whereas palmitate in the presence of albumin revealed a wide range of optimal concentration in supporting maximal enzyme activity, oleate was found to strongly inhibit the reaction. Where substrate specificity with both the total homogenate and the microsomal fraction was concerned, maximal reaction rates were obtained with palmitate for the long chain saturated fatty acids C12:0' C14:0' C16:0' and C18:0' and with oleate for the long chain unsaturated fatty acids C18:1 C18:2' and C18:3' respectively. The highest specific activity of the enzyme was localised in the microsomal fraction. The kinetic data and properties of the long chain fatty acid: CoA ligase from human intestine are discussed with respect to the intestinal enzyme from other species.     

Biochemical basis for cisplatin and 5-fluorouracil synergism in human ovarian carcinoma cells.

The human ovarian cell line A2780 was exposed to either cisplatin (10 microM) or 5-fluorouracil (5FUra) (5 microM) for 1 hr. Cytotoxicity was less than 14% with either agent alone. Cisplatin (10 microM) and 5FUra (5 microM) in combination for 1 hr caused a 76% reduction in cell growth. Thymidine (dThd, 10 microM), if given concomitantly with the combination of cisplatin and 5FUra, completely protected the tumor cells. A 30-min exposure to cisplatin increased the intracellular pools of 5,10-methylenetetrahydrofolate and tetrahydrofolate 2.5-fold. The capacity of intact cells to form 5-fluorodeoxyuridylate (FdUMP)-thymidylate (dTMP) synthase complex when incubated with fluorodeoxyuridine (FdUrd) was enhanced 2.5-fold when the cells were pretreated with cisplatin. These experiments demonstrate that cisplatin can increase the availability of the reduced folate necessary for tight binding of FdUMP to dTMP synthase, thus enhancing the cytotoxicity of the cisplatin and 5FUra combination.     

Randomized trial comparing weekly bolus 5-fluorouracil plus leucovorin versus monthly 5-day 5-fluorouracil plus leucovorin in metastatic colorectal cancer

BACKGROUND/AIMS: The purpose of this study was to compare the efficacy and toxicity profiles of weekly intravenous (i.v.) bolus injection of 5-fluorouracil plus low-dose leucovorin with the Mayo Clinics' monthly 5-day schedule of 5-fluorouracil and leucovorin in the treatment of metastatic colorectal cancer. METHODOLOGY: A total of 96 patients with previously untreated metastatic colorectal cancer were randomized to receive either a weekly i.v. bolus injection of 5-fluorouracil 400 mg/m2 plus leucovorin 20 mg/m2 (weekly arm), or i.v. bolus injection of 5-fluorouracil 425 mg/m2 plus leucovorin 20 mg/m2 for 5 consecutive days every 4 or 5 weeks (monthly arm). Therapy was continued until disease progression or unacceptable toxicity appeared. In the presence of disease progression, the study regimen was stopped and second-line treatment was instituted after the patient was discontinued from this study. RESULTS: There was no significant difference of response rates between both regimens. The response rate were 14.3% in the weekly arm (2 CR and 5 PR, 95% CI: 2.6-25.2%) and 10.6% in the monthly arm (1 CR and 4 PR; 95% CI: 6.5-32.3%), respectively (P = 0.8957). The survival times were also similar between the two (P = 0.4207, log-rank test). The median survival were 15.8 months in the monthly arm and 18.4 months in the weekly arm. Hematologic toxicity was minimal in both arms. However, the monthly arm produced a higher toxicity in severe (grade 3-4) diarrhea (14.9% vs. 2%; P = 0.029) and stomatitis (8.5% vs. 0; P = 0.054). CONCLUSIONS: Weekly bolus injection of 5-fluorouracil and low-dose leucovorin achieved a similar response rate and survival as compared with the Mayo Clinics' monthly 5-day schedule, but severe toxicity was less commonly seen using the weekly regimen. As current chemotherapeutic treatment for metastatic colorectal cancer is largely palliative rather than curative, the weekly bolus regimen may be a more favorable approach in managing metastatic colorectal cancer.     

Systemic combined chemotherapy with low dose of 5-fluorouracil,cisplatin, and interferon-alpha for advanced hepatocellular carcinoma: a pilot study

The purpose of this pilot study was to evaluate the efficacy and adverse events of systemic combined chemotherapy with low dose of 5-fluorouracil (250 mg/m², 5 days), cisplatin (10 mg/m², 5 days), and interferon- (2.5 million units, three times weekly) for advanced hepatocellular carcinoma (HCC) underlying liver cirrhosis. Six patients who had advanced HCC with tumor thrombi in the main portal trunk were enrolled in this study. Partial response was achieved in 2, stable disease in 1, and disease progressed in 3. Objective responses were achieved in 2 (33%), however, marked decreases of -fetoprotein protein and protein-induced vitamin K antagonist or absence (PIVKAII) levels were also seen in one patient (stable disease). Four patients showed hematologic or renal toxicity, which were well tolerated and managed. Our systemic combined chemotherapy resulted in favorable response and was well tolerated in those with advanced HCC underlying liver cirrhosis, complicated by leukocytopenia and thromobocytopenia.     

Systemic gemcitabine combined with intra-arterial low-dose cisplatin and 5-fluorouracil for advanced hepatocellular carcinoma： Seven cases

The combination of intra-arterial low-dose cisplatin and 5-fluorouracil （5-FU） is effective against advanced hepatocellular carcinoma （HCC）. Systemic gemcitabine chemotherapy seems effective in many cancers. We report the results of combination therapy with systemic gemcitabine, intra-arterial low-dose cisplatin and 5-FU （GEMFP）. Seven patients with non-resectable advanced HCC were treated with GEMFP. One course of chemotherapy consisted of daily intra-arterial cisplatin （20 mg/body weight/hour on d 1, 10 mg/body weight per 0.5 h on d 2-5 and 8-12）, followed by 5-FU （250 mg/body weight per 5 h on d 1-5 and 8-12） via an injection port. Gemcitabine at 1000 mg/m2 was administered intravenously at 0.5 h on d 1 and 8. The objective response was 57%. The response to GEMFP was as follows： complete response （no patients）, partial response （four patients）, stable disease （three patients）, and progressive disease （no patients）. The median survival period was 8 mo （range, 5-55）. With regard to the National Cancer Institute Common Toxicity Criteria （NCI-CTC） grade 3 or 4 adverse reactions, seven （100%）, seven, six （86%） and one （14%） patients developed leukopenia, neutropenia, thrombocytopenia and anemia, respectively. GEMFP may potentially be effective for non- resectable advanced HCC, but it has severe hematologic toxicity.     

Phase II trial of 5-fluorouracil,high-dose leucovorin calcium,and dipyridamole in advanced prostate cancer

Summary To examine the effect of altering intracellular folate pools on the efficacy of 5-fluorouracil (FUra) in the treatment of advanced prostate cancer, we performed a phase II trial of FUra (300–370 mg m^–2 day^–1×5 as an i.v. bolus) combined with high-dose folinic acid (500 mg m^–2 day^–1×5.5 days by continuous i.v. infusion) and dipyridamole (75 mg p.o. every 6h×5.5 days) administered on a 28-day schedule in patients with stage D₂ disease. A group of 13 patients have been treated. The median age was 68 years (range 48–78 years); the performance status ranged from 50% to 90%. Among 12 evaluable patients, there were no objective responders; the median time to progression was 1.9 months. Median survival after entry on this trial was 8.6 months. Treatment with FUra, high-dose folinic acid and dipyridamole was well tolerated. Only one episode each of grade 3 leukopenia, granulocytopenia, and thrombocytopenia was observed. These results suggest that, despite previous trials demonstrating activity for FUra in stage D₂ prostate cancer, this disease may be relatively resistant to fluoropyrimidines and, thus, less amenable to biochemical modulation with high-dose folinic acid and dipyridamole.This study was supported, in part, by NCI Cancer Center support grant CA 33572     

Microsomal UDP-glucuronyltransferase-catalyzed bilirubin diglucuronide formation in human liver

Human liver microsomal bilirubin UDP-glucuronyltransferase catalyzes formation of bilirubin mono- and diglucuronide. KmUDPGA and Vmax of the enzyme are 0.6 mM and 1.69 nmol/mg protein X min. In vitro, bilirubin readily dissolves in the microsomal lipid phase. Taking this into account a Kmbilirubin of 60.6 microM was found, which is much higher than the in vivo microsomal UCB concentration of human liver (2.9-11.4 microM). The total capacity of human liver to form bilirubin mono- and diglucuronide in vitro exceeds the in vivo mono- and diglucuronide production rates by a factor 8 to 10. Radiation-inactivation studies reveal that human liver microsomal bilirubin UDP-glucuronyltransferase is a tetrameric enzyme with a molecular mass of 209 000 +/- 20 000 Da. The complete tetrameric enzyme catalyzes both glucuronidation steps, formation of bilirubin monoglucuronide and conversion of mono- to diglucuronide. In its monomeric form, the enzyme with molecular mass of 55 000 +/- 1 500 Da catalyzes only the first step of bilirubin glucuronidation, the formation of bilirubin monoglucuronide.     

Pharmacokinetics and tissue distribution of intraperitoneal 5-fluorouracil with a novel carrier solution in rats

AIM： To compare the pharmacokinetics and tissue distribution of 5-fluorouracil administered intraperitoneally with two isotonic carrier solutions： HAES-steri （neotype 6% hydroxyethyl starch）, a novel carrier solution with middle molecular weight and physiologic saline （0.9% sodium chloride solution）, a traditional carrier solution for intraperitoneal chemotherapy, in rats. METHODS： A total of 60 Sprague Dawley rats were randomized into groups according to the carrier solution administered. Each group was further randomized according to the intraperitoneal dwell period （1, 3, 6, 12, 18 and 24 h）. At the end of the procedure the rats were killed, the peritoneal fluid was withdrawn completely and quantitated. Drug concentrations in peritoneal fluid, plasma, and tissues were determined by high- performance liquid chromatography. RESULTS： The mean volumes remaining in the peritoneal cavity were significantly higher with HAES- steri than those with physiologic saline at 1, 6, 12, 18, and 24 h （P = 0.047, 0.009,0.005, 0.005 and 0.005 respectively, the percentages of remaining peritoneal fluid volume were 89.9 ± 5.6 vs 83.4 ± 4.9, 79.9 ± 2.8 vs 56.2 ± 15.7, 46.8 ± 5.5 vs 24.7 ± 9.7, 23.0 ± 2.8 vs 0.0 ± 0.0 and 4.2 ± 1.7 vs 0.0 ± 0.0 respectively）. Mean concentrations in peritoneal fluid were significantly higher with HAES-steri than those with physiologic saline at 3, 12 and 18 h （P = 0.009, 0.009 and 0.005 respectively, the concentrations were 139.2768 ± 28.2317 mg/L vs mg/L, 11.5427 ± 3.0976 mg/L vs 0.0000 ± 0.0000 mg/L and 4.7724 ± 1.0936 mg/L vs 0.0000 ± 0.0000 mg/L respectively）. Mean plasma 5-fluorouracil concentrations in portal vein were significantly higher with HAES-steri at 3, 12, 18 and 24 h （P = 0.009, 0.034, 0.005 and 0.019 respectively, the concentrations were 3.3572 ± 0.8128 mg/L vs 0.8794 ± 0.2394 mg/L, 0.6203 ± 0.9935 mg/L vs 0.0112 ± 0.0250 mg/L, 0.3725 ± 0.3871 mg/L vs 0.0000 ± 0.0000 mg/L, and 0.2469 ± 0.1457 mg/L vs 0.0000 ± 0.0000 mg/L respective