Hypoxia-inducible factor 1α promotes interleukin 1ß and tumour necrosis factor α expression in lipopolysaccharide-stimulated human dental pulp cells.

AIM: To elucidate the role of HIF1α in pro-inflammatory cytokine mRNA expression from lipopolysaccharide (LPS)-stimulated human dental pulp cells (hDPCs). METHODOLOGY: mRNA expression of interleukin (IL) 1ß and tumour necrosis factor (TNF) α in LPS-stimulated hDPCs was determined by quantitative RT-PCR. Expression of nuclear factor kappa B (NFκB) p65 and phospho-NFκB p65 was analysed by Western blotting. Activation of NFκB signalling was measured by luciferase assay using a reporter vector containing an NFκB response element. Enforced expression of HIF1α was induced by transfection of expression vectors with native or constitutively active forms of HIF1α. Expression of HIF1α protein in hDPCs was evaluated by immunocytochemistry and Western blotting. One-way analysis of variance and the Tukey-Kramer test were performed to determine a significant difference (P < 0.05). RESULTS: mRNA expression of IL1ß and TNFα, protein expression of phospho-NFκB p65 and LPS-induced NFκB signalling activity were promoted in low oxygen conditions (1% O2 ; P < 0.05). These findings were replicated following enforced expression and stabilization of HIF1α in hDPCs. Dimethyloxalylglycine, an inhibitor of prolyl hydroxylase (a HIF1α degrading enzyme), promoted IL1ß and TNFα mRNA expression and NFκB signalling in LPS-stimulated hDPCs (P < 0.05). HIF1α expression was detected in hDPCs cultured in low oxygen conditions (1% O2 ). LPS stimulation further enhanced HIF1α expression in hDPCs, especially within their nuclei. CONCLUSION: HIF1α promoted mRNA expression of IL1ß and TNFα via NFκB signalling in LPS-stimulated hDPCs, suggesting that HIF1α is involved in the progress of inflammation in dental pulp.

Mineral trioxide aggregate suppresses pro-inflammatory cytokine expression via the calcineurin/nuclear factor of activated T cells/early growth response 2 pathway in lipopolysaccharide-stimulated macrophages.

AIM: To elucidate mechanisms by which mineral trioxide aggregate (MTA) suppresses pro-inflammatory cytokine mRNA expression in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. METHODOLOGY: Mineral trioxide aggregate extracts were prepared by immersing set ProRoot MTA in culture medium. RAW264.7 cells were cultured in the presence of LPS and MTA extracts. mRNA expression levels of interleukin (IL)-1α, IL-6, early growth response 2 (Egr2), suppressor of cytokine signalling 3 (Socs3) and IL-10 were quantified with reverse transcription-quantitative polymerase chain reaction. Phosphorylation of nuclear factor-kappa B (NF-κB) p65 in RAW264.7 cells was analysed by Western blotting. Intracellular calcium imaging was performed with Fluo-4 AM. The activity of nuclear factor of activated T cells (NFAT) was determined by luciferase assays. Enforced expression and silencing of Egr2 in RAW264.7 cells were carried out using an expression vector and specific RNAi, respectively. In vivo kinetics of Egr2+ cells in MTA-treated rat molar pulp tissues were examined using immunohistochemistry. Data were analysed by one-way analysis of variance, followed by the Tukey-Kramer test (P < 0.05). RESULTS: Exposure to MTA extracts resulted in reduced mRNA expression levels of IL-1α and IL-6, as well as reduced expression of phosphorylated NF-κB, in LPS-stimulated RAW264.7 cells. Exposure to MTA extracts induced Ca2+ influx, which was blocked by NPS2143, an antagonist of calcium-sensing receptor (CaSR); Ca2+ influx then triggered activation of calcineurin/NFAT signalling and enhanced mRNA expression of Egr2. Enforced expression of Egr2 in RAW264.7 cells promoted the expression of both IL-10 and Socs3. In vivo application of MTA onto rat molar pulp tissue resulted in the appearance of Egr2-expressing cells that coexpressed CD163, a typical M2 macrophage marker. CONCLUSIONS: Mineral trioxide aggregate extracts induced downregulation of IL-1α and IL-6 in LPS-stimulated RAW264.7 cells via CaSR-induced activation of calcineurin/NFAT/Egr2 signalling and subsequent upregulation of IL-10 and Socs3.

Argyrophil cell microneoplasia in the Mastomys' stomach--an observation on early carcinoid formation.

To analyze the early stages of argyrophil cell carcinoid growth, complete serial sections were cut from the glandular portion of the stomachs of 22 Mastomys and submitted to Sevier-Munger's reaction. The 154 grossly invisible foci of argyrophil cell microproliferation thus detected were classified into three stages of microproliferations (I, II, and III), and the last stage was definitely a microcarcinoid. There was a gradual transition in cell proliferation among these three stages; the first stage (microproliferation I), in which the cells were morphologically indistinguishable from those of hyperplastic proliferation by general morphologic criteria, was where the initial change of argyrophil cell carcinoid formation was detectable by a light microscope. Whereas multiple occurrences of microcarcinoids accounted for the multiplicity of well-developed tumors in the stomachs of Mastomys, a well-developed carcinoid in this species was formed by the confluence of several microcarcinoids.

Inhibitory effects of fluorinated pyrimidines, 5'-DFUR, UFT and T-506, in a model of hepatic metastasis of mouse colon 26 adenocarcinoma-assessment of inhibitory activity and adverse reactions at the maximum tolerated dose.

The effects of fluorinated pyrimidines, 5'-DFUR, UFT and T-506, on a mouse model of hepatic metastasis were assessed in regard to inhibitory activity and adverse reactions at the maximum tolerated dose. The model was prepared by injecting the mouse colonic cancer cell line, colon 26, into the portal vein of CDF1 mice. At the treatment regimens employed for 5'-DFUR (1.0 mmol/kg/day, p.o., daily from days 1 to 7), UFT (0.1 mmol/kg/day, p.o., daily from days 1 to 7), and T-506 (0.074 mmol/kg/day, i.v., days 1, 4, 7, and 10), complete inhibition of hepatic metastasis was obtained in six out of seven mice (85.7%) with 5'-DFUR, and in five out of six mice (83.3%) with T-506. Significant inhibition of hepatic metastasis was not achieved with UFT (3/7, 42.9%). 5'-DFUR and T-506 showed the highest rate of inhibition of hepatic metastasis, suggesting that these drugs would be effective for the prophylactic treatment of metastatic disease. 5'-DFUR and UFT exhibited mild adverse reactions such as loss of body weight.

Tumor regression by inductive hyperthermia combined with hepatic embolization using dextran magnetite-incorporated microspheres in rats.

We formulated a novel preparation of microspheres incorporating dextran magnetite complex (DM-MS), which enable magnetic field-induced heating for the induction of hyperthermia. Using a 500 kHz magnetic field combined with arteriolar embolization of DM-MS, inductive hyperthermia was performed for the treatment of liver tumors in rats. Three days after treatment, the percentage increase of tumor volume in the embolo-hyperthermia, embolization alone, and control groups were 28%, 124%, and 385%, respectively, with the embolo-hyperthermia group differing significantly from the remaining groups. This study demonstrated the feasibility of combining embolization of DM-MS with hyperthermia as an antitumor therapy.

CEA immunohistochemical localization is correlated with growth and metastasis of human gallbladder carcinoma.

Carcinoembryonic antigen (CEA) is a good marker of colorectal cancer. Recent studies have demonstrated that CEA may function as a metastatic potentiator by different pathways; i.e., modulation of immune responses, facilitation of intercellular adhesion and cellular migration. However, expression patterns of CEA have not yet been established in human gallbladder carcinomas. In this study, we examined CEA expression in human gallbladder adenocarcinomas and its clinicopathological significance. CEA immunoreactivity was detected not only in the cancer cells (cytoplasmic type: 63.0%, 34/54) but also in the cancer stroma (stromal type: 29.6%, 16/54). According to TNM classification, 75.0% (30/40) of T2-4 gallbladder cancers showed cytoplasmic CEA, while 28.6% (4/14) of the T1 cancers were cytoplasmic CEA-positive (p<0.05). Stromal CEA expression was detected in 40.0% (16/40) and none (0/14) of the T2-4 and T1 cancers, respectively (p<0.05). Lymph node metastasis was frequently found in the cytoplasmic CEA- and stromal CEA-positive gallbladder cancers (44.1% and 62.5%, respectively). These observations suggested that CEA expression plays important roles in cancer cell growth and metastasis of human gallbladder adenocarcinomas.

Clinical results of treatment of advanced esophageal carcinoma with hyperthermia in combination with chemoradiotherapy.

Chemoradiotherapy combined with hyperthermia was administered to 35 patients with advanced esophageal carcinoma who either required preoperative treatment or had nonresectable disease. As a rule, each patient received a total dose of 30 Gy in 15 daily fractions of 2 Gy, 5 d/wk. Bleomycin or cisplatin, in combination with fluorouracil, was employed as chemotherapy. Hyperthermia was applied by intraluminal heating twice a week for a total of six sessions using an apparatus (IH-500T; Japan Crescent Co Ltd; Tokyo, Japan) (radiofrequency, 13.56 MHz) with an intraesophageal applicator and two extracorporeal applicators placed on the chest and back. This treatment method obtained a response rate of 80%, consisting of a complete response rate of 22.9% and partial response of 57.1%. In 15 cases, the tumor became resectable (resectability rate, 42.9%) following treatment. The histologic study of the resected specimens revealed absence of viable tumor cells in five patients (33.3% of the resected cases) (markedly effective), and in six patients (40.0%), the combined therapy was considered to be moderately effective. No complications considered due to hyperthermia itself were recognized. The overall 5-year survival rate was 11.8%. In conclusion, chemoradiotherapy combined with hyperthermia was locally effective, yielding an overall response of 80.0%. However, the prognosis of the patients remains unfavorable. Advanced esophageal carcinoma requires treatment taking into account lymphatic and hematogenic metastasis at the beginning of treatment.

Augmentation of murine lymphokine-activated killer cell cytotoxicity by beta-cyclodextrin-benzaldehyde.

We investigated the effect of beta-cyclodextrin-benzaldehyde (CDBA) on lymphokine-activated killer (LAK) cell activity of spleen cells from normal or RCT(+)H-2(+)-sarcoma-bearing C3H/He mice. CDBA augmented the induction of LAK cytotoxicity in vitro against RCT(+)H-2+ tumor cells by IL-2, whereas the culture with CDBA alone did not. In a LAK cytotoxicity assay in vitro, the augmentative effect of CDBA was strongly exerted against spleen cells originating from 2-week-tumor-bearing mice, rather than those from normal mice or mice that had born tumors for 5 weeks. Such an augmentative effect was not observed against other tumor cells (YAC-1, D-6, Colon-26 and EL-4 cells) non-specifically. When the intravenous adoptive transfer of LAK cells was carried out in the mice, LAK cells from tumor-bearing mice induced by combined culture with interleukin-2 (IL-2) and CDBA markedly inhibited the pulmonary metastases of RCT(+)H-2+ tumor, while neither LAK cells from the same tumor-bearing mice induced by only IL-2 nor those from normal mice inhibited the pulmonary metastasis. The majority of LAK cells induced either by IL-2 plus CDBA or by IL-2 alone were found to be Thy1.2+ and asialoGM1+ cells by flow-cytometric analysis, but no obvious phenotypical difference was observed between them. However, the most significant effect of CDBA might be the maintenance of the Lyt-2+ cell level in the spleen cells from tumor-bearing mice. These results suggested that the costimulation of spleen cells with IL-2 and CDBA might induce cytotoxic T cells specific for syngeneic tumor cells.

Relation of H-2 expression on murine RCT(+) sarcoma cells to lung colonization and sensitivity to NK cells.

Murine RCT(+) sarcoma cells were sorted using a fluorescence-activated cell sorter with regard to the expression of H-2 antigens and then an increased H-2-expressing subclone was established, and named RCT(+)H-2+. The experimental metastasis of RCT(+) cells was compared with that of RCT(+)H-2+ cells by counting pulmonary colonies on the 21st day after i.v. inoculation of tumor cells (5-10 x 10(4)/mouse). When mice were inoculated with RCT(+) cells, mean numbers of pulmonary colonies were 2.1(range 0-6), 2.8(range 0-7) using 5 x 10(4) and 1 x 10(5) cells, respectively. On the other hand, in the mice inoculated with RCT(+)H-2+ cells, figures obtained were 7.0(range 4-16), 31.9(range 13-79), using 5 x 10(4) and 1 x 10(5) cells, respectively. The survival rate of RCT(+)H-2+ cells was higher than that of RCT(+) cells, when this was assayed in the early stage after i.v. injection of 51Cr-labeled cells (1 x 10(5) cells/mouse). In addition, RCT(+)H-2+ cells were more resistant than RCT(+) cells to lysis mediated by natural killer cells. These data suggest that an increase in metastatic ability was paralleled by an increase in the H-2 antigen expression and a decrease in sensitivity to the natural killer cells.

Strangulation ileus resulting from encasement of a loop of the small intestine by the great omentum, caused by abnormal adhesion.

We treated a patient with a mechanical ileus resulting from encasement of a loop of the small intestine by the great omentum, caused by abnormal adhesion. Apart from its occurrence postoperatively with laparotomy, strangulation of small intestine into the omentum is very rare, and its occurrence without underlying disease, except in children, has not been documented previously.

Hepatocellular carcinoma presenting as extrahepatic mass on computed tomography.

The authors describe an extremely rare case of extrahepatic hepatocellular carcinoma. The patient was a 70-year-old man who was examined by a local doctor because of abdominal discomfort. Barium meal examination demonstrated a defect occupying the lesser curvature of the stomach from the middle of the corpus to the fornix. On an abdominal computed tomography (CT) scan, the lesion, 10 cm in diameter, touched the lower surface of the caudate lobe of the liver. Under laparotomy, the tumor was found between the caudate lobe of the liver and posterior wall of the gastric corpus. As the tumor appeared to be connected with the caudate lobe by a pedicle, only the tumor was resected. Histological examination showed the tumor to be hepatocellular carcinoma of Edmondson's grade III-IV, pedunculated type.

Magnetic targeting of thermosensitive magnetoliposomes to mouse livers in an in situ on-line perfusion system.

We recently reported the preparation and in vitro targeting of dextran magnetite (DM)-incorporated thermosensitive liposomes, namely thermosensitive magnetoliposomes (TMs) [Viroonchatapan et al. Pharm. Res. 12 1176-1183 (1995)]. The current study was designed to determine whether these novel liposomes can be targeted to the mouse liver with the aid of an extracorporeal magnet. An on-line liver perfusion system consisting primarily of a sample injector, permanent magnets, and a fluorescence detector was established for a real-time measurement of targeting efficiency of TMs containing calcein as a fluorescent marker. Normal and reticuloendothelial system (RES)-blocked livers from mice were used for the perfusion experiments. In the RES-blocked livers, percentage holdings of TMs were 73-80% and 26-45% in the presence and absence of magnetic field, respectively, indicating an efficient targeting of TMs with a targeting advantage index (TAI) of 1.6-3.1. On the other hand, TAI in the normal livers was found to be 1.1-1.4 and less than that in the RES-blocked livers, suggesting a role of RES uptake of TMs. The effects of DM concentrations in TM suspensions on the percentage holding of TMs were shown to be minor. Liposome concentration dependence was observed for hepatic uptake of TMs, possibly because of the saturation of phagocytosis by Kupffer cells. The present results suggest that TMs would be useful in future cancer treatment by magnetic targeting combined with drug release in response to hyperthermia.

Microdialysis assessment of 5-fluorouracil release from thermosensitive magnetoliposomes induced by an electromagnetic field in tumor-bearing mice.

The current study was designed to evaluate the properties of thermosensitive magnetoliposomes (TMs), a new drug carrier proposed by the authors, in an electromagnetic field pertaining to their selective heating and drug release under an in vivo condition. TMs containing 5-fluorouracil (5-FU) were prepared by reverse-phase evaporation, injected into the tumor mass of B 16-BL6 melanoma in mice, and selectively heated by a 500-kHz electromagnetic field. The release profile of 5-FU from TMs was examined by using a microdialysis technique. The temperature of TMs in the tumor was effectively elevated to 42 degrees C and maintained at this temperature, overcoming the "cooling effect" of blood flow and surrounding tissues. The release kinetics of 5-FU from TMs was successfully analyzed by physiological modeling, which allows the prediction of intratumor drug concentrations during electromagnetic field exposure under various conditions. In conclusion, this study first demonstrated an in vivo evidence for the electromagnetic field-induced thermosensitive release of a drug from TMs in a tumor with the use of microdialysis.

Asymptomatic acute poststreptococcal glomerulonephritis following upper respiratory tract infections caused by Group A streptococci.

During an observation period of 1-2 years in 2 different districts in Japan, 104 patients were found to have upper respiratory infections caused by group A streptococci. Fourty-nine of these patients were followed prospectively to determine if renal involvement would occur. Twelve patients developed transient serum complement (CH50) depression and urinary abnormality, and 2 of these developed mild hypertension. The latent period was from 1-8 weeks after the streptococcal infection. Renal biopsies of the 12 patients with "asymptomatic" of "subclinical" acute poststreptococcal glomerulonephritis (APSGN) were examined by light, immunofluorescent and electron microscopy. Glomerular lesions ranged from mild proliferative changes to the classical pathology seen in APSGN. The 12 patients were followed for 10 years. Two of them developed persistent or intermittent hematuria, and renal biopsies obtained 4 years after the initial infection revealed mesangial proliferative glomerulonephritis without IgA deposits. The remaining patients showed no abnormal findings after the acute episode. These findings suggested that glomerular involvement after group A streptococcal infection is frequent and mesangial proliferative glomerulonephritis, which was found to develop in some, may rank with IgA nephropathy as a major cause of unexplained microscopic hematuria.

Synergistic antiproliferative effect of delta 12-prostaglandin J2 (delta 12-PGJ2) and hyperthermia on human esophageal cancer cell lines.

delta 12-PGJ2, one of the cyclopentenone prostaglandins and the ultimate metabolite of prostaglandin D2, has been reported to have potent antiproliferative activity on various tumor cells in vitro and in vivo. In this study, the combined effect of delta 12-PGJ2 and hyperthermia on six established cell lines of human esophageal carcinoma (SGF series) was analyzed by an in vitro assay, and the degree of apoptosis induced by this combination was examined to clarify the mechanism of supra-additive effects. In five SGF cell lines, except SGF-7 cells, combination therapy with delta 12-PGJ2 and hyperthermia showed synergistic antiproliferative effects. The supra-additive combined effect of delta 12-PGJ2 and hyperthermia on esophageal cancer cells is attributed to the synergistic induction of apoptosis. delta 12-PGJ2 induced G1 accumulation and apoptosis was induced by delta 12-PGJ2 from G1 phase. Hyperthermia induced G1 accumulation and apoptosis was induced by hyperthermia during all cell phases. Both augmented G1 arrest followed by G1 phase-selective induction of apoptosis and increased apoptotic induction without cell-cycle specificity are responsible for the synergism of combined treatment with delta 12-PGJ2 and hyperthermia.

TNF receptor number-dependent cytotoxicity to TNF-resistant human esophageal cancer cell lines by combination with recombinant human necrosis factor and hyperthermia.

The synergistic effect of recombinant human tumor necrosis factor (rh-TNF) and hyperthermia on five established cell lines of human esophageal cancer (SGF series) was analyzed by in vitro assays. The SGF cell lines were either resistant or slightly sensitive to rh-TNF. However, they became highly sensitive to rh-TNF even at as low a concentration as 10 U/ml and dose-dependently when combined with hyperthermia (43.5 degrees C, 60 min). This result was due to synergistic effects of rh-TNF and hyperthermia, and the degree of the effect increased with the hyperthermic temperature and TNF concentration. The number of TNF receptors per cell varied widely from cell line to cell line, from 4,400 to 23,100, which did not correlate to the extent of cytotoxicity by rh-TNF alone. The degree of synergistic effect of rh-TNF and hyperthermia was evaluated quantitatively in terms of a Synergistic Index (S. I. = Predicted cell viability/Experimental cell viability): A significant correlation was found between the logarithmic S. I. and the number of TNF receptors. These findings indicated that the combination of rh-TNF and hyperthermia produced a significant antitumor effect even on the cell lines poorly sensitive to TNF in a receptor-dependent manner, although the cellular sensitivity to TNF alone was not directly correlated to the number of TNF receptors.

[Dietary fiber inhibits the incidence of hepatic metastasis with the anti-oxidant activity and portal scavenging functions].

Dietary fiber is described as the proportion of plant foods not digested in the human small intestine. Among the various kinds of pectin, apple pectin exerts a bacteriostatic action and therefore may change the composition of the intestinal flora. The diet supplemented with 20% apple pectin significantly decreased the number and the incidence of AOM-induced colon tumors in rats. The prostaglandin E2 (PGE2) level in the distal colonic mucosa and blood of portal vein was lower in rats fed 20% pectin than those fed the basal diet. The ability of apple pectin to decrease PGE2 was dose-dependent and those results suggest an anti-inflammatory effect in the bowel. Rats fed apple pectin showed a significantly lower incidence of hepatic metastasis than those fed the basal diet. To determine whether the anti-inflammatory effect of Lactobacillus on hepatic metastasis model same as apple pectin, Lactobacillus casei was selected. Metastatic nodules were significantly reduced, especially in the group receiving pretreatment. Apple pectic oligosaccharides with small molecular weights showed highly inhibitory effects on hypoxanthin-xanthin oxidase and ferrous sulfate-hydrogen peroxide. The scavenging activity of apple pectic oligosaccharides was suitable and accelerated at high temperatures (120 degrees C, 30 min.). Apple pectin and Lactobacillus have a scavenger effect in the intestinal digestion and portal circulation system as an anti-inflammatory food and have very important function for the prevention of hepatic metastasis.

[Character of a human cholangiocarcinoma CHGS, serially transplanted to nude mice].

With the progress in surgical technique, remarkable improvement has been noted in the treatment of bile duct carcinoma. However, in the cholangiocarcinoma at porta hepatis or in the progressive carcinoma, many cases have been reported, for which radical surgery is not achievable. In recent years, discussion has been concentrated on the necessity of multidisciplinary treatment for the bile duct carcinoma, but fundamental research has not been done enough. In the present paper, the process for obtaining CHGS strain implantable to the nude mouse derived from a human cholangiocarcinoma as achieved in our department was discussed, and its biological characteristics-above all, the sensitivity to carcinostatic agents and to radiation-were evaluated. The doubling time of CHGS strain is 6.2 days, and nude mice showed stable proliferation with 100% viability. Histologically, it was tubular adenocarcinoma similar to the primary tumor. It has high mucin producing ability, and necrosis hardly occurs. The search for DNA ploidy by flow cytometry revealed the presence of two types of cells: The cells of diploid pattern and aneuploid pattern. In the tests to determine the sensitivity of CHGS strains to carcinostatic in MMC, ADR, 5-FU and CDDP groups, and to radiation according to the Battele Columbus Laboratories Protocol, the regression of tumor was observed in MMC, ADR, CDDP groups. Particularly, in MMC group, some of the tumors had disappeared. Recurrence was also noted in this case, but the survival, was still recognized nearly four years after the operation through the postoperative auxiliary therapy. This was regarded as the case, where the sensitivity test using the nude mouse implantable tumor strain was reflected well in clinical application.

Effect of hyperthermia on proliferation and deviation of carcinoembryonic antigen and squamous cell carcinoma-related antigen of human esophageal carcinoma cells in culture.

As a basic study of hyperthermia on malignant tumors, we investigated the kinetics of proliferative activity and the values of tumor markers carcinoembryonic antigen (CEA) and squamous cell carcinoma-related antigen (SCC) in a human esophageal carcinoma cell line, SGF-4, following a change of culture temperature. The temperature range allowing cultured SGF-4 cells to proliferate was from 37 degrees C to 40 degrees C. In an experiment examining the recovery of proliferative activity, no proliferative activity was observed after the cultured cells were exposed to 42 degrees C for 72 hours. The values of CEA and SCC as tumor markers were found to be increased in association with the cell damage due to the change of temperature. These markers could thus be useful as indicators for evaluations of hyperthermia therapy effectiveness.

Anticarcinogenic action of apple pectin on fecal enzyme activities and mucosal or portal prostaglandin E2 levels in experimental rat colon carcinogenesis.

Pectin is a partially methoxylated polymer of galacturonic acid obtained from fruits. Among pectin, apple pectin exerts stronger bacteriostatical action on Staphylococcus aureus, Streptococcus faecalis, Pseudomonas aeruginosa and Escherichia coli in comparison with citrus pectin. In this study, we used water-soluble methoxylated pectin from apple. The diet, supplemented by 20% apple pectin, significantly decreased the number of tumors and the incidence of colon tumor. PGE2 level in distal colonic mucosa in 20% apple pectin fed rats were lower than those in basal diet fed rats. Fecal beta-glucuronidase activities in the apple pectin fed group, which has been considered a key enzyme for the final activation of Dimethylhydrazine metabolism to carcinogens in the colonic lumen, were signifieantly lower than those in control group at initiation stage of carcinogenesis. In the case the concentrations of beta-glueosidase and azoreductase were also decreased. The effect of apple pectin on the colon carcinogenesis may partially depend on PGE, concentration decrease in colonic mucosa and on the type of pectin, also related to fecal enzyme activities.