Biomedical subjects
I Kawamura
Publications and source records attributed to I Kawamura.
[Proceedings: Effect of various types of vagotomies on local blood flow of the gastric mucosa and gastric motility].
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Portable fluorospirograph. A simple method for estimation of individual lung ventilation.
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[Establishment of the Japanese Nursing Association].
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[Construction of new buildings for a nursing school].
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[Activities of the Nursing Association and the position of its members].
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[Method of examination of partial lung physiology by Xe-133].
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Optimum branched-chain amino acids concentration for improving protein catabolism in severely stressed rats.
In this study, an experiment was performed to investigate the optimal concentration of branched chain amino acid (BCAA) in hyperalimentation to be administered when protein catabolism is accelerated by sepsis or bodily injury. Amino acid solutions containing BCAA 25%, 30%, 40%, 45% and 50% were prepared and were administered iv for three days with other essential amino acid-containing nitrogen in the same volume into rats with peritonitis which had been developed by ligature and puncture at the cecum, and the results were compared. After observing for three days, the influence over nitrogen balance, improvement of 3-methyl-histidine/creatinine in urine, weight loss in muscles, and aminogram in serum and muscles indicated that the hyperalimentation under stress is utilized most effectively when amino acid contains 45% of branched-chain amino acid.
Occurrence of an intrahepatic porto-arterial shunt after hepatic artery embolization with Gelfoam powder in rats and rabbits.
Postmortem perfusion studies were carried out following hepatic artery embolization (HAE) with Gelfoam powder in rats (n = 17) and rabbits (n = 10). The inflow of barium particles into the hepatic arteries after portal vein injection (porto-arterial shunt: P-A shunt) was analyzed by stereomicroscopic and histologic examinations. A P-A shunt was observed in 12 of 17 rats (71%) following HAE (embolization group). The difference in occurrence rates of P-A shunt between control (1/12 = 9.2%) and embolization groups was statistically significant (chi 2, p less than 0.01) in rats. In rabbits, a P-A shunt was seen in only one of 10 animals in the embolization group. P-A shunting may have an important role in reconstructing the blood supply to hepatic tumors after HAE, and administration of anticancer drugs via the portal vein following HAE might be effective. However, the differences among different species of animals should be considered before clinical application.
Activation of lipoprotein lipase and inhibition of B16 melanoma-induced cachexia in mice by ponalrestat, an aldose reductase inhibitor.
Lipoprotein lipase (LPL) is a key regulatory enzyme responsible for the hydrolysis of triglyceride (TG)-rich lipoproteins. The reduction in LPL activity is observed in tumor bearing animals and cancer patients with cachectic symptoms, suggesting an involvement of LPL in inducing cancer cachexia. During a screening program for anti-cachectic agents we found that ponalrestat, an aldose reductase inhibitor, activates LPL activity. Ponalrestat increased the activity of LPL in adipose tissue in mice. The effect of ponalrestat on B16 melanoma-induced cachectic symptoms was next investigated in mice. The decrease in the weight of epididymal fat, carcass and whole body lipid was observed in mice following intraperitoneal inoculation of B16, compared to mice without the tumor inoculation. Treatment with ponalrestat resulted in the attenuation of the decrease in the tissue weight. The increase in the levels of TG and non-esterified fatty acid, and a decrease in the level of glucose in the blood, which was induced by the presence of tumor, were also restored to those of normal mice following ponalrestat treatment. The reduction in locomotor activity in tumor bearing mice was partially restored by the treatment with ponalrestat. Overall, this study demonstrated that ponalrestat, an aldose reductase inhibitor, possesses potent LPL activating activity and that the cachexia induced by B16 melanoma was alleviated by treatment with 'ponalrestat, suggesting that ponalrestat, a LPL activating agent, has a therapeutic potential for the treatment of cancer cachexia.
Ponalrestat, an aldose reductase inhibitor, inhibits cachexia syndrome in nude mice bearing human melanomas G361 and SEKI.
Our recent study has demonstrated that ponalrestat, an aldose reductase inhibitor, activates lipoprotein lipase (LPL) activity in the adipose tissue and alleviates the cachectic symptoms induced by B16 melanoma in mice. In this study, the effect of ponalrestat on cachexia symptoms in nude mice bearing human melanomas G361 and SEKI was investigated because it has been suggested that the suppression of LPL has an important role in cachexia induction by these two melanomas in nude mice. Mice bearing G361 subcutaneously did not gain weight and became cachectic, associated with the tumor growth. Tumor growth was not affected by ponalrestat, nevertheless treatment with ponalrestat resulted in an amelioration of the reduction in the weight of body mass, epididymal fat, gastrocnemius muscle, carcass and whole body lipid induced by the presence of G361. A severe weight loss observed in nude mice bearing SEKI was also partially attenuated by ponalrestat treatment. Overall, this study showed that ponalrestat is effective in the attenuation of the cachectic symptoms induced by human melanomas G361 and SEKI in nude mice, suggesting that ponalrestat has a potential usefulness for the treatment of cancer cachexia.
Effect of lipoprotein lipase activators bezafibrate and NO-1886, on B16 melanoma-induced cachexia in mice.
Our recent study has demonstrated that B16 melanoma-induced cachexia in mice is inhibited by ponalrestat, an aldose reductase inhibitor, which has the ability to activate lipoprotein lipase (LPL) activity both in vitro and in vivo. In this study, the effect of bezafibrate and NO-1886, LPL activators, on B16 melanoma-induced cachectic symptoms was investigated in mice. Treatment with bezafibrate resulted in an attenuation of the decrease in the weight of epididymal fat and whole body lipid observed in mice following intraperitoneal inoculation of B16. The increase in the levels of triglyceride and non-esterified fatty acid, and a decrease in the level of glucose in the blood, which was induced by the presence of tumor, were also restored to that of normal mice after treatment with bezafibrate. The reduction in the weight of epididymal fat and whole body lipid induced by B16 was also ameliorated by NO-1886. Overall, this study demonstrated that cachexia induced by B16 melanoma in mice was alleviated by the LPL activators bezafibrate and NO-1886, suggesting the involvement of the impaired LPL activity in the establishment of cachexia syndrome in mice bearing B16 melanoma.
Ponalrestat, an aldose reductase inhibitor, inhibits cachexia syndrome induced by colon26 adenocarcinoma in mice.
Our recent study has demonstrated that ponalrestat, an aldose reductase inhibitor, activates lipoprotein lipase activity and alleviates B16 melanoma-induced cachexia in mice. In this study, the effect of ponalrestat on murine adenocarcinoma colon26-induced cachexia was investigated in mice. Mice bearing colon26 subcutaneously lost weight and became cachectic, associated with the tumor growth. Although tumor growth was slightly stimulated when tumor bearing mice were treated with ponalrestat: nevertheless, the drug attenuated the reduction in the weight of body mass, epididymal fat, gastrocnemius muscle and carcass induced by colon26, as well as significantly prolonged the survival of the colon26 bearing mice. Ponalrestat inhibited the production of interleukin-1 (IL-1) from human monocytes stimulated by Lipopolysaccharide (LPS) in vitro, and also suppressed LPS-induced increase of IL-1 in the blood in mice. Overall, this study showed that ponalrestat suppresses IL-1 production both in vitro and in vivo, and inhibits the cachectic symptoms induced by colon26 adenocarcinoma in mice, suggesting that ponalrestat has a therapeutic potential for the treatment of cancer cachexia.
Cachexia induction by EL-4 lymphoma in mice and possible involvement of impaired lipoprotein lipase activity.
Several lines of evidence have postulated that reduction in the activity of lipoprotein lipase (LPL) is involved in cachexia induction in cancer patients. Recently we have demonstrated that murine melanoma B16 has the ability to reduce the LPL activity and thereby induce cachexia symptoms in mice following intraperitoneal inoculation. In order to further investigate the relationship between LPL activity and cachectic syndrome, cachexia models other than melanoma B16 are required. However, there are few animal cachexia models in which LPL activity is involved in the induction of cachectic symptoms. In this study, cachectic symptoms and plasma LPL activity were investigated in mice bearing EL-4 mouse lymphoma. In EL-4 bearing mice the body weight including tumor weight in the abdominal cavity was rather higher than that of normal mice without tumor, whereas weights of carcass wet and gastrocnemius muscle were significantly decreased in EL-4 bearing mice. Elevated blood levels of triglyceride and non-esterified fatty acid were observed in mice bearing EL-4, associated with the impaired plasma LPL activity. Overall, this study indicated that EL-4 lymphoma in mice results in a severe cachexia which is possibly related to impaired LPL activity and also provided a useful cachexia model for understanding the role of LPL in the development of cancer cachexia.
Induction of bone loss by bile duct ligation in rats.
Metabolic bone loss is the most common complication of chronic liver disease. However, there is little information available about bone loss in rats with a ligated bile duct, a biliary-type of experimental cirrhosis model. Therefore, in this study, the effect of bile duct ligation (BDL) on bone mineral density (BMD) and plasma insulin-like growth factor-I (IGF-I) levels was examined in rats. Two weeks after BDL operation, the rats with a ligated bile duct showed a pronounced and significant decrease in both trabecular and cortical BMD of the femur. In these rats, decreases in food intake and plasma IGF-I levels plus elevated levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and bilirubin were also observed. When the effect of dietary restriction (30% or 50%) over 2 weeks was then investigated in normal rats, 50% food restriction resulted in a significant decrease in femoral trabecular bone density although BMD was unchanged by 30% dietary restriction. The plasma levels of IGF-I were also decreased in food-restricted rats. Thus, the decrease in femoral bone density in 50% food-restricted rats was less potent compared with BDL rats; nevertheless, the decrease in plasma levels of IGF-I was almost equally potent in both BDL and food-restricted rats. Overall, this study showed that BDL operation resulted in a pronounced bone loss in rats, but also that this bone loss might not be merely due to the decreases in food intake and plasma IGF-I levels. These results suggest that BDL in rats is a useful experimental cirrhosis model for evaluating the bone loss associated with chronic liver disease.
The effect of droloxifene on the insulin-like growth factor-I-stimulated growth of breast cancer cells.
Insulin-like growth factor-I (IGF-I) is an important mitogen in breast cancer. We studied here the effects of a new antiestrogen drug, droloxifene (DROL, (E)-alpha-[p-[2-(dimethylamino) ethoxy]-phenyl]-alpha'-ethyl-3-stilbenol) and tamoxifen (TAM) on the IGF-I-stimulated growth of estrogen receptor (ER) positive breast cancer cells, MCF-7 and their mechanism of action. IGF-I secretion from MCF-7 was increased by the addition of estrogen. Externally added IGF-I stimulated the growth of MCF-7 but not ER negative breast cancer cells, MDA-MB-231. DROL and TAM inhibited the IGF-I-stimulated growth of MCF-7. A 2 hr treatment with both drugs did not block IGF-I binding to the receptors in MCF-7. However, a 4 day treatment with DROL decreased the number of IGF-I receptors without altering the binding affinity in MCF-7. These results suggest that DROL can exert its antitumor activity against ER positive breast cancer not only by blocking the E2 binding to the ER, but also by counteracting the mitogenic effect of IGF-I.