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Biomedical subjects

M Mito

Publications and source records attributed to M Mito.

At least 73 records · Page 4Linked to original sources
PubMed1992

[A study of progression in hepatocarcinogenesis using cell transplantation system].

It is important to distinguish a precancerous lesion and hepatocellular carcinoma (HCC) with diploidy or aneuploidy nuclear DNA pattern, not only in clinical cases but also in experimental carcinogenesis models. Using liver perfusion technique, we detected early HCC from persistent hyperplastic nodules (HN) which were induced in Wistar rats by intermittent 5-6 months administration of 2-acetylaminofluorene. This investigation was undertaken to assess both promotive and progressive effects of liver regeneration following partial hepatectomy (PH). Results are as follows: 1) Isolated hepatocytes of precancerous HN, which were transplanted into the spleen, didn't develop to HCC by 2 months after 70% PH of host liver. 2) Diced tissues of HCC, which were transplanted into the liver via portal vein, grew many metastasis in 10/10 by 7 weeks after PH, while 5/19 in control. 3) Nuclear DNA patterns of early HN-late HCC in rat liver were diploidy at the rate of more than 90% each. But it changed to aneuploidy, when inoculation of HCC for one month was repeated 7 times in the spleen.

Animals↗
PubMed1992

[Hemostatic control in platelet dysfunction and abnormality by DDAVP].

DDAVP infusion shortens the bleeding time in patients with some types of platelet dysfunction and may be useful for hemostatic control. In order to clarify the mechanism of DDAVP to correct or bypass the release defect, we examined the effect in 17 patients with prolonged bleeding time, i.e., 11 with various kinds of platelet dysfunction, 4 with idiopathic thrombocytopenic purpura (ITP), 1 with chronic myelocytic leukemia (CML), and in an aspirin-ingested volunteer. DDAVP shortened the bleeding time in 9 patients with platelet dysfunctions, one with ITP, and the one aspirin ingested volunteer. No improvement was found in the aggregability and the retention rates, and no signs of activation occurred in the platelet shape. The RCof was elevated in all of the patients after the infusion. Our data suggests that DDAVP improves the hemostasis through primary aggregation and release of dense bodies, and not directly through an increase of RCof.

Bleeding Time↗
PubMed1991

[Experimental study on the characteristic features of sympathetic nervous system reactions in dogs with obstructive jaundice].

Possible abnormalities in the sympathetic nervous system responsible for circulatory disturbances with obstructive jaundice were investigated by determining the reactions of the heart and peripheral blood vessels using alpha.beta receptor stimulants or blockers. Mongrel dogs were randomly assigned to three groups: untreated (UT) and sham-operated (SO) controls and 3-week-old bile duct ligated (BDL). Under anesthesia with Nembutal, circulatory parameters and blood catecholamine concentration were measured. In term of alpha- and beta-adrenergic reactions, reactions in the sympathetic nervous system to alpha- and beta-receptor stimulants were examined. Mean arterial pressure (MAP) and heart rate were used as an alpha-adrenergic parameter and a beta-adrenergic parameter, respectively. The hemodynamic study in BDL group was characterized by a reduction in MAP (p less than 0.05), total peripheral resistance (p less than 0.005) and left ventricular stroke work (LVSW) (p less than 0.05) and by an increase in cardiac index (p less than 0.05). The blood norepinephrine concentration was significantly increased in jaundice (p less than 0.01). Reaction to the beta-receptor stimulant was significantly decreased in BDL group. In response to the alpha-receptor stimulant, lower reactivity was found in some animals in BDL group in comparison to SO group. Taking this into consideration with the increase in blood norepinephrine and the decrease in LVSW, the presence of abnormalities particularly in the beta-adrenergic system (receptor, cardiac muscle etc.) in jaundice is suggested to be a characteristic feature of reactions in the sympathetic nervous system. Such abnormalities are speculated to be responsible for postoperative shock.

Animals↗
PubMed1991

[DNA ploidy and the S-phase fraction and their prognostic significance in gastrointestinal tumors].

The prognostic significance of nuclear DNA ploidy patterns and the S-phase fraction (labeling index; IL) were evaluated in 365 gastrointestinal tumors, and in 62 of them a combined analysis of DNA ploidy and the SPF was performed. For accurate evaluation, we used fresh frozen specimens, and we classified the ploidy pattern into 6 types; 1. diploid, 2. DS (diploid + high LI), 3. Notch, 4. Shoulder, 5. Tetraploid and 6. Aneuploid. Type 1 or type 2 tumors were classified as diploid, and the others were classified as aneuploid. In 103 cases of gastric cancer and 101 colon cancers due to the short observation period, but in 46 patients with operable primary liver cancer, a significant difference was observed. A high average of LI was detected in colon cancer (approximately 13%), but no relationship between LI and the ploidy pattern was found. This indicates that the LI may become an independent prognostic factor, and that the combined assay of DNA ploidy and the LI may offer a more precise evaluation of the malignant potential of gastrointestinal tumors.

DNA, Neoplasm↗
PubMed1991

[The present status and the future of artificial liver support].

Orthotopic liver transplantation, started by Dr. Starzl in 1963, has already become an well established therapeutic method for the treatment of fulminant hepatic failure especially since the introduction of Cyclosporin A. On the other hand, hemoadsorption using charcoal, PAN membrane hemodialysis and plasma exchange were actively applied for clinical cases with fulminant hepatic failure between 1960 and 1970, but the survival rates were not so improved as expected due to the lack of metabolic functions. Hybrid artificial liver has been therefore investigated experimentally to support metabolic functions by using biomaterials such as isolated hepatocytes. Today many efforts are being made to keep hepatocytes highly viable for a long period of time by calcium alginate entrapment, spheroid formation, or by using biomatrix, some polymers, and microcarriers, etc. In the future, xeno-hepatocytes or so-called super cell will be realized and applied for artificial liver support with the development of gene operation techniques.

Artificial Organs↗
PubMed1990

[Protective effects of DBcAMP on ischemic liver failure in dogs].

We studied protective effects of Dibutyryl cyclic AMP (DBcAMP) which is a permeable form of cyclic AMP on ischemic liver failure (ischemic time: 90 minutes). Mongrel dogs were used. A portal-systemic bypass was established by inserting a heparinized catheter between the splenic vein and the femoral vein. Acute liver failure was induced by the en bloc clamp of the porta hepatis. In the treated group, 0.1 mg/kg/min (total dose, 300 mg) of DBcAMP was injected intravenously from three hours before the clamp to the end of the experiment. The control group was injected physiological saline. Effects of DBcAMP were evaluated according to survival rates, blood pressure, serum biochemical findings, hepatic blood flow, ATP levels in liver tissues and histological findings. The survival rates were 16% in the control group, and 88% in the treated group. The mean blood pressure after reperfusion was rapidly decreased in the control group while in the treated group, it was maintained nearly 100 mmHg. Serum biochemical findings, hepatic blood flow and tissue ATP levels were significantly improved in the treated group. On histological findings, necrosis with bleeding was observed one day after ischemia in the control group while in the treated group mild chronic ischemic change without necrosis was observed on two weeks after ischemia. In conclusion, ischemic liver failure was apparently protected by the administration of DBcAMP.

Adenosine Triphosphate↗
PubMed1990

[31P nuclear magnetic resonance study of intrahepatic energy metabolism in acute liver failure].

Changes in phosphorus metabolites and intracellular pH in acute liver failure induced by D-galactosamine (GAL) were evaluated non-destructively and continuously using 31P-NMR spectroscopy. Furthermore, changes in these parameters under ischemia were also examined. GAL(1.0g/kg) was injected intravenously to male Wistar rats. NMR measurements in perfused livers were performed with a GX-270FT NMR spectrometer (JEOL). Typical changes in 31P-NMR spectra were observed after GAL administration. ATP levels decreased to 57.4 +/- 12.4% at 12 hours and to 65.4 +/- 7.7% at 24 hours after the administration compared with that in control rats. Pi levels increased remarkably to 632.1 +/- 76.4% at 3 hours and recovered to 127.5 +/- 22% at 24 hours. NAD+/NADH and UDP-sugar levels gradually increased to 253.5 +/- 33.4 and 456.3 +/- 60.9%, respectively, at 24 hours. In GAL treated livers, ATP levels fell rapidly and Pi levels rose correspondingly during ischemia, and they rapidly recovered by reperfusion. The intracellular pH decreased to 7.16 +/- 0.032 from 7.38 +/- 0.065 at 3 hours after GAL administration. However, significant changes in pH were not observed until 24 hours. In GAL treated livers, slight changes in pH were observed under ischemia. These results indicate that 31P-NMR is a useful method to evaluate the damage of acute liver failure, and to diagnose liver diseases involving the intrahepatic energy metabolism.

Acute Disease↗
PubMed1989

Cooperative study on arterial regional chemotherapy for primary liver cancer in Hokkaido.

The Liver Study Group of Hokkaido analyzed a total of 57 patients with non-resectable primary liver cancers, which were treated by intra-arterial adriamycin infusion chemotherapy combined with lipiodol and/or the Gelform embolization of the hepatic arteries. Of the ten patients considered clinical responders, three complete response patients and seven partial response cases were obtained. The overall response rate was 17.5%. The median survival period at each clinical stage was as follows: stage I: 13.0 months, stage II: 16.0 months, stage III: 11.5 months and stage IV: 4.7 months. The common side-effects of this treatment were nausea, vomiting and anorexia. Hematological toxicities were also found, but there was no patient who suffered from severe complications.

Adult↗
PubMed1989

[Effect of activation of the reticuloendothelial system on hepatocyte regeneration in partially hepatectomized rats].

Enhanced effect on rat hepatocyte regeneration through activation of the reticuloendothelial system (RES) was investigated. RES was activated using by OK-432 and the phagocytic activity (K-value) increased 2-fold over control rats 24 hours after intraperitoneal injection of OK-432. In OK-432 treated rats, the amount of cyclic AMP in the regenerating liver also increased 1.5-fold higher than in control rats 14 hours after hepatectomy. After 70% partial hepatectomy, liver DNA synthesis in OK-432 treated rats increased 2 to 5-fold higher than in control rats. There was a good correlation between the K-value before hepatectomy and DNA synthesis 24 hours after hepatectomy (r = 0.96). Therefore the RES is one of the most important regulatory factors in liver regeneration. Augmentation of RES before hepatectomy may prevent hepatic failure after resection in liver diseases.

Animals↗
PubMed1989

[Protective effects of DBcAMP on acute liver failure induced by D-galactosamine in rats].

We studied protective effects of Dibutyryl cyclic AMP (DBcAMP) which is a permeable form of cyclic AMP (cAMP), the intracellular second messenger, on D-galactosamine (D-Gal, 1.5g/kg i.p.) induced acute liver failure. Experimental animals were divided into four groups: Group I; DBcAMP was administered before (7.5mg/kg) and after (7.5mg/kg) D-Gal treatment, group II; only before (15mg/kg) D-Gal treatment, group III; only after (15mg/kg) D-Gal treatment, and group IV; no DBcAMP was administered. Effects of DBcAMP were evaluated according to survival rates, serum biochemical findings and hepaplastin test (HPT), ATP levels in liver tissues, hepatic blood flow, and histological findings. The survival rates after D-Gal treatment were 100% in group I, 90% in group II, 32% in group III and 10% in group IV. The serum biochemical findings, tissue ATP levels and hepatic blood flow were significantly improved in groups I and II compared with that in groups III and IV. The level of HPT in group I was the highest among the experimental groups. On histological findings, inflammatory changes were observed in group I and focal necrosis in group II while liver degeneration with massive necrosis was seen in groups III and IV. In conclusion, acute liver failure induced by D-Gal was apparently protected by the administration of DBcAMP.

Acute Disease↗
PubMed1988

A study of liver regeneration using fetal rat liver tissue transplanted into the spleen.

The liver morphology of fetal hepatic tissue transplanted into an ectopic location was investigated over one year period. Fetal liver fragments prepared from a maternal rat on the 18th or 19th day of pregnancy were injected into the splenic parenchyma of syngeneic rats using a 21 gauge needle. Histologically, the fetal liver did not essentially show any apparent lobular architecture or cord structure. The transplanted fetal hepatic tissues survived and formed hepatic cords in the spleen instead of undergoing degeneration and necrosis. Three characteristic features became complete during the 4 weeks following transplantation, namely; clumps of hepatocytes with obvious hepatic cords and sinusoids, markedly proliferating bile ducts and proliferating individual hepatocytes. Macroscopic nodules of the hepatocytes on the spleen were seen at about 6 months after transplantation. When the differentiation of the transplanted fetal hepatic tissue was compared with the development of a normal neonatal liver after birth, it was delayed by only about one week, while there was no proliferation of bile ducts in the normal neonatal liver. This experimental model provides a useful system for investigating liver regeneration and the mechanism of cell growth.

Animals↗
PubMed1988

[Human cell transplantation].

To summarize this review: it was written concerning human cell transplantations from various human organs based on already published historical reports. It was limited to only clinical cases for therapeutic treatment. Some of the methods in the article are commonly used, well-established methods found in everyday practice. Others are still in the experimental stages. I think we can try these, or even never methods for other cell groups in the near future.

Adrenal Medulla↗