Biomedical subjects
Publications and source records attributed to K Fujimoto.
A 68-year-old man with the clinical features of Cronkhite-Canada syndrome developed cancer of the ascending colon. Although Cronkhite-Canada syndrome has always been considered a benign condition, it may be a premalignant disorder, as suggested by the clinical course of the patient whose case is described herein.
The MRI and CT studies of four patients with ganglion cell tumours, one with a cerebellar gangliocytoma (Lhermitte-Duclos disease), and three with gangliogliomas are reported. MRI in Lhermitte-Duclos disease clearly demonstrated a mass of low signal intensity in the left cerebellum on T1-weighted spin-echo (SE) images and an area of high signal intensity with a blurred margin on T2-weighted SE images. These MRI studies were useful for delineating the lesion, which was verified at surgery. In the ganglioglioma, MRI demonstrated two isointense solid masses on T1-weighted SE images, which enhanced clearly with Gd-DTPA. The enhancement study was advantageous in planning surgery.
The present study shows that various cytokines such as tumor necrosis factor (TNF alpha), interleukin-1 alpha (IL-1 alpha), and interferon-gamma (IFN gamma) make tumor cells much more susceptible to the cytostatic 5'-deoxy-5-fluorouridine (5'-dFUrd) than to 5-fluorouracil (5-FUra) and other cytostatics. These three cytokines increased the susceptibility of human cancer cell lines (COLO201, MKN45 and WiDr) but did not affect that of normal fibroblast WI38 cells. The cytokine mixture induced a 50-fold increase in the susceptibility of COLO201 to 5'-dFUrd, whereas a 12-fold increase and a less than 5-fold enhancement in the susceptibility to 5-FUra and other cytostatics, respectively, were observed. The increased susceptibility would be a result of the induction of thymidine phosphorylase (TdR Pase), which is the essential enzyme for the conversion of 5'-dFUrd to 5-FUra. The cytokine mixture increased TdR Pase activity by up to 47 times and greatly induced its mRNA expression in the cancer cell lines. These results suggest that the therapeutic benefit of 5'-dFUrd would be improved by its use in combination with the cytokines.
To examine the roles of histamine and diamine oxidase in the intestine after ischemia-reperfusion, we measured histamine content, diamine oxidase activity, and ornithine decarboxylase activity in rat intestinal mucosa 6 hr following various periods of ischemia. In addition, mortality rates of rats after various periods of ischemia were observed. The superior mesenteric artery was occluded for 15, 30, or 60 min. Ornithine decarboxylase activity increased in the 15-, 30-, and 60-min ischemic groups compared to the sham-operated control group. In the prolonged ischemic group (60-min ischemia), both histamine concentration and diamine oxidase activity in the mucosa decreased, contributing to an increase in circulating histamine. In the 60-min ischemic group, the mortality rate of rats was 25%, which was significantly larger than the control groups. Pretreatment with aminoguanidine, which suppressed diamine oxidase activity, increased the mortality rate. These results indicate that histamine released from the intestinal mucosa has a harmful effect on rats, and diamine oxidase activity plays an important role when the small intestine is subjected to prolonged period of ischemia.
The levels of phosphatidylcholine hydroperoxide in serially cultured human fetal diploid fibroblasts at various population doubling levels were determined by high-performance liquid chromatography combined with chemiluminescence detection. This methodology utilizes a mixture of cytochrome c and luminol as post-column hydroperoxide group specific luminescent reagents. The cellular hydroperoxide content increased with age from 0.34 to 27.72 pmol/10(6) cells. At the end of the cells' in vitro lifespan (51st population doubling level), the hydroperoxide content per 10(6) cells reached about 80 times the level found in cells of the 20th population doubling level. Supplementation of exogenous alpha-tocopherol to the culture medium prevented hydroperoxide accumulation, but did not extend the lifespan in vitro. The results indicate that substantial intracellular phospholipid hydroperoxide accumulation occurred in the course of aging of human fetal diploid fibroblasts.
Age-related changes in phosphatidylcholine hydroperoxide (PCOOH) content as an index for oxidative membrane lipid damage were determined by high-performance liquid chromatography using chemiluminescence detection. Brain and liver PCOOH content increased significantly in male and female rats with age. The brain PCOOH content of male 18-month-old rats was 4.4 times that of 1-month-old rats, and that of female 18-month-old rats was 3.5 times that of 1-month-old females. The liver PCOOH content of the male 18-month-old rats was 9.3 times that of the 1-month-old; and of the female 18-month-old rats was 4.7 times that of the 1-month-old. PCOOH levels in heart and lung did not show age dependency. In both brain and liver (but not in heart and lung), the phosphatidylcholine content significantly decreased upon aging. The results indicate that oxidative deterioration, such as phospholipid hydroperoxidation, is prevalent in the membrane lipids of brain and liver of the rat due to aging.
In order to evaluate the systemic and neural factors on ornithine decarboxylase (ODC) activity of rat intestinal mucosa, ODC activity in duodenal mucosa, where blood flow did not decrease by superior mesenteric artery (SMA) occlusion, was compared to that of jejunal and ileal mucosa, where blood flow decreased to 90% of the initial value after SMA occlusion. Rats were allowed to recover after SMA occlusion before harvesting intestinal mucosa for measuring ODC activity. ODC activity in the jejunum and the ileum increased markedly 6 h after ischemia-reperfusion (I/R) and more than 72 h were required for ODC activity to return to normal. ODC activity in the duodenum did not change until 24 h after I/R, but the activity increased 48 h after I/R, and this increase continued for 2 days. Subdiaphragmatic vagotomy completely abolished the increase in ODC activity in the duodenum, whereas the same procedure had no influence on ODC activity in the jejunum or the ileum. These results indicate that a neural signal from the central nervous system via the efferent vagal nerve following I/R was an important factor in the increase in ODC activity of duodenal mucosa, where blood flow was not influenced by SMA occlusion.
Effects of ginsenoside Rg1 (Rg1) on histaminergic modulation of both adaptive behavior and thermoregulation were investigated at high ambient temperature. Continuous infusion of Rg1 using an osmotic minipump into the rat third cerebroventricle attenuated anorexia induced by elevation of ambient temperature from 21 degrees C to 31 degrees C. Intraperitoneal injection of alpha-fluoromethylhistidine (FMH), a specific suicide inhibitor of a histamine synthesizing decarboxylase enzyme, also prevented the anorexia induced by elevated temperature. The ratio of water intake to food intake, which showed no change on the first day after elevation of room temperature, was not influenced by treatment of either FMH or Rg1. Rectal temperature, which was normally maintained at a constant level even after shifting ambient temperature from 21 degrees C to 31 degrees C, elevated after FMH treatment. The Rg1 infusion, however, maintained rectal temperature normally at 31 degrees C. Hypothalamic histamine content increased in response to elevation of ambient temperature. The Rg1 infusion maintained constant histamine level against elevation of environmental temperature. Under the heated condition FMH reduced hypothalamic histamine. These findings suggest that Rg1 may modulate rat adaptive behavior by blockade of temperature-related information into the hypothalamic histamine neurons.
Histaminergic functions in the hypothalamus of Zucker obese rats were investigated. Blockade of postsynaptic H1-receptor after infusion of chlorpheniramine into the third cerebroventricle (ICV) failed to affect feeding in obese Zuckers, although feeding was potently elicited in Wistar King A control rats. Presynaptic increase in histamine by an H3-receptor antagonist, thioperamide, suppressed feeding in Wistar controls, but not in obese Zuckers. Under high ambient temperature, Wistar controls decreased food intake and maintained their rectal temperature normally. However, obese Zuckers and histamine depleted rats due to alpha-fluoromethyl-histidine (FMH), a specific "suicide" inhibitor of a histamine synthesizing decarboxylase enzyme (HDC), failed to show this decrease in food intake as adaptive behavior. Their rectal temperature concomitantly elevated in response to heated circumstance. ICV infusion of thioperamide increased the blood glucose level in Wistar controls, but not in obese Zuckers. The defect in all these regulatory functions found in obese Zuckers may be derived from an excessive decrease in hypothalamic histamine content due to inactivity of HDC. The histamine-depleted model sufficiently mimicked the abnormalities in obese Zuckers.
Surface modification of polyurethane by glow-discharge treatment and subsequent graft polymerization of acrylamide was studied. The modified hydrophilic surfaces were characterized by the measurements of dynamic contact angle and zeta potentials and examined for protein adsorption behaviour and platelet adhesion. Data from in vitro and ex vivo experiments indicated a reduction of protein adsorption and platelet adhesion for the hydrophillic graft polymers, the extent of which was correlated to polymer graft density.
A high incidence of hepatocellular carcinoma (HCC) was observed in mice fed a choline-deficient diet containing 0.1% ethionine (CDE) for 19 months. HCC was present in 85% of CDE mice and in 22% of choline-deficient (CD) mice not receiving ethionine. This strong hepatocarcinogenicity of the CDE diet was concomitant with a severe decrease in plasma and liver alpha-tocopherol (Toc) to 60 and 35%, respectively, of those contained in choline-supplemented (CS) control mice. We previously found that this dietary-induced HCC was preceded at 4-week feeding by a depletion of Toc and a remarkable increase of phosphatidylcholine hydroperoxide (PCOOH) in the livers of CDE mice. When HCC was prominent in CDE mice, PCOOH was still elevated. Mouse glutathione S-transferase (GST) M II isozyme, which is related to rat GST-P form, a positive marker for rat hepatic preneoplastic and neoplastic lesions, revealed an inverse histochemical pattern as that seen in rats (i.e., the HCC lesions tended to decreased staining). The aforementioned results taken together indicate that decreases in Toc and enhanced PC peroxidation are important events in CDE-induced mice liver tumors.
Activation with 2-propanol and other organic compounds of prophenoloxidase purified from pupae of Drosophila melanogaster was analyzed. A1, one of the two isozymes of the prophenoloxidase, could be activated with both an endogenous activating system and artificial organic compounds including alcohols. A1 was activated within 2 min after addition of 2-propanol. The phenoloxidase activity of A1, which had been activated with 2-propanol, decreased gradually by lowering the concentration of 2-propanol taking c 60 min to attain a low level, and the activity could be re-elevated at the re-introduction of 2-propanol. Thus the reversibility of the activation of A1 in response to the change of the concentration of 2-propanol in the activating mixture could be observed. Optimum concentration of 2-propanol for the rate of activation was 50%, optimum temperature was 30 degrees C and optimum pH was 7.5. The final level of the phenoloxidase activity, which had been activated with 2-propanol, was higher than that activated with the endogenous activating system. The activated state of A1 showed properties of a tyrosinase-type phenoloxidase. The results suggested that the activation of A1 with 2-propanol is caused by the reversible conformational change of the prophenoloxidase molecule.
Two isoforms of prophenoloxidase were isolated from pupae of Oregon-R strain of Drosophila melanogaster. The purification procedure included ammonium sulfate fractionation, Sephacryl S-200 gel chromatography, DEAE-cellulose, and hydroxylapatite column chromatography. The two isoforms, A1 and A3, could be separated by ammonium sulfate fractionation. The isoelectric points of A1 and A3 were determined to be pH 5.8 and 6.7, respectively. The molecular weights of the monomers of A1 and A3 were estimated by SDS-PAGE to be 78 and 77 kDa, respectively. The native states of A1 and A3 are considered to be homodimeric, as judged by gel-filtration chromatography.
The histamine H1 receptor gene was isolated from a guinea-pig gene library. The gene contains no introns and encodes a protein of 488 amino acid residues. The structure of the guinea-pig histamine H1 receptor is predicted to contain seven putative transmembrane regions, which are similar to those of receptors coupling with GTP binding proteins. Although the third intracellular domain, the predicted binding site for the GTP binding protein, showed only 50% identity with those of the bovine and rat H1 receptors, the expressed guinea-pig H1 receptor was fully able to bind with [3H]mepyramine. Northern blot analysis indicated that the cerebrum, cerebellum, lung, adrenal, intestine, and heart expressed 3.3 kb guinea-pig H1 receptor mRNA. Expression of histamine H1 mRNA of guinea-pig peripheral organs was greater than that of rat organs, suggesting the high sensitivity of guinea-pig organs as to histamine is due to the contents of histamine H1 receptor mRNA. In addition, the lung, adrenal, intestine, and heart expressed 3.9 kb mRNA. In situ hybridization showed that the hippocampus, cerebral cortex, thalamus, and granular layer of the cerebellum each contained a large amount of histamine H1 receptors. Southern blot analysis showed that there was another gene quite similar to the cloned histamine H1 receptor gene.
The effects of a seleno-organic compound, Ebselen [2-phenyl-1,2-benzoisoselenazol-3(2H)-one], on phospholipid hydroperoxide levels in in vitro and in vivo systems were examined by using high-performance liquid chromatography with chemiluminescence detection (CL-HPLC) as a tool for measuring the hydroperoxide. In in vitro systems, the phosphatidylcholine hydroperoxide (PCOOH) content in phosphatidylcholine (PC) liposomes was significantly reduced by co-incubation with exogenously added Ebselen; 85, 97, and 99.6% of PCOOH was eliminated with 1, 10, and 100 microM Ebselen, respectively. In human plasma, 79, 87, and 86% of PCOOH was eliminated after the incubation with 1, 10, and 100 microM Ebselen, respectively. In an in vivo study involving single oral administration of Ebselen (10, 30, and 100 mg/kg rat) to rats, plasma PCOOH (48.8 nM for Ebselen-untreated rat) was significantly decreased to 26.3, 5.6, and 3.3 nM at 2 h after the administration and 6.7, 7.4, and 4.8 nM at 4 h after the administration, respectively. These in vivo effects on plasma PCOOH elimination depended on both the dose and the time after the administration. Maximum decrease of plasma PCOOH appeared around 2-4 h after oral administration. The liver and red blood cell PCOOH levels were not affected by oral Ebselen under the present conditions. These findings indicate that the Ebselen may be a potent agent for lowering plasma PCOOH levels in vivo.
The pharmacokinetics of (glycolato-O,O')diammine platinum(II) (254-S), especially the distribution and behavior in the lung lymph in sheep, was investigated and compared with that of cis-diamminedichloroplatinum(II) (CDDP). The blood and lung lymph fluid were collected from the carotid artery and a lung lymph fistula, respectively, in conscious sheep following intravenous infusion of 100 mg/body of 254-S and CDDP for 30 min. The concentrations of these platinum complexes were measured by using atomic absorption spectrometry. We analyzed the data using an anatomically based model including part of the lymphatic circulation. The ultrafilterable platinum of 254-S showed much larger area under the curve (AUC) and transfer rate constants than that of CDDP, even though the mean residence times were the same. The total platinum showed the opposite pharmacokinetic behavior. In anesthetized sheep, when lung tissue samples were obtained by biopsy at the same times as those of blood and lung lymph sampling after infusion of these drugs, 254-S distributed in lung tissue appeared to move more easily into lung lymph than CDDP, which tended to be retained in lung tissue. These differences in pharmacokinetic behavior between 254-S and CDDP seemed to be caused by differences in their strength of protein binding; the association constants of 254-S for plasma and lymph protein were much less than those of CDDP. From these results, 254-S may have favorable therapeutic effects on intrathoracic malignancies such as lung cancer and lymph metastasis.
The antiproliferative activity of 5-fluorouracil (5-FUra) and 5'-deoxy-5-fluorouridine (5'-dFUrd), used in combination with typical cytokines and growth factors, was investigated in mouse colon 26 carcinoma cells. Tumor necrosis factor alpha (TNF alpha), interleukin-1 alpha (IL-1 alpha), and interferon gamma (IFN gamma) at low doses showing < 50% inhibition of cell growth by themselves enhanced the susceptibility of the cells to the activity of 5'-dFUrd. In particular, a mixture of these cytokines greatly enhanced the activity of 5'-dFUrd and 5-FUra by up to 12.4- and 2.7-fold, respectively, whereas the activity of other cytostatics was only slightly changed (< 1.5-fold). Basic fibroblast growth factor also increased the susceptibility, but only to 5'-dFUrd. This preferential enhancement of the activity of 5'-dFUrd would be due to induction by the cytokines of uridine phosphorylase (Urd Pase), by which 5'-dFUrd is converted to 5-FUra. TNF alpha, IL-1 alpha, IFN gamma, and a mixture of these factors increased the enzyme activity by up to 3.7-fold in colon 26 cells. Consequently, the anabolism of 5'-dFUrd to fluoronucleotides and the incorporation of 5-FUra into RNA in colon 26 cells were increased by TNF alpha treatment. In addition, the increase by the cytokine mixture in the susceptibility to 5'-dFUrd was abolished by an inhibitor of Urd Pase, 2,2'-anhydro-5-ethyluridine. These results indicate that induction of Urd Pase activity by cytokines is a critical event that increases the susceptibility to 5'-dFUrd.
The ability of recombinant human interleukin-11 (IL-11) to stimulate rat megakaryopoiesis and thrombopoiesis in vivo was investigated. Once daily subcutaneous injections of IL-11 at doses of 2, 8 and 20 micrograms/rat for 5 d caused dose-dependent increases in platelet counts. The chronic administration of 20 micrograms/rat/d for 14 d resulted in biphasic increases in platelet counts with peaks at days 8 and 15 of up to 30% over the control, continuing for more than 5 d after cessation of IL-11 injections. Moreover, a striking increase in megakaryocytic size and ploidy in bone marrow in response to IL-11 was elicited. IL-11 induced a dose-dependent elevation in bone marrow cell numbers but not in splenic weight and cell numbers. Modifications of these parameters were noted as soon as 24 h after the first IL-11 injections. IL-11 had a same potency of thrombopoietic effect in rats as compared with IL-6. However, elevation of acute phase protein such as immunosuppressive acidic protein was 2.2-fold in rats given 20 micrograms/d of IL-6 over those receiving a same dose of IL-11 (470 v 210 micrograms/ml). In addition, the rate of body-weight increase in rats receiving IL-11 for 5 d as well as 14 d did not differ from that in control animals. In IL-6 treated rats, the increase in body weight was significantly slower than the controls, which was observed even in the group given 8 micrograms/d of IL-6. These results suggest that IL-11 may be an effective strategy for the treatment of thrombocytopenia.