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Biomedical subjects

K Kagawa

Publications and source records attributed to K Kagawa.

At least 145 records · Page 8Linked to original sources
PubMed1987

Immunoglobulin M antibody to hepatitis B core antigen (IgM anti-HBc) as a marker of interferon therapy in patients with persistent hepatitis B virus infection.

Immunoglobulin M antibody to hepatitis B core antigen (IgM anti-HBc) was measured by radioimmunoassay in the sera of 96 HBV carriers. IgM anti-HBc was detected in 17 of 66 patients with chronic active hepatitis and in 4 of 11 with liver cirrhosis. This antibody was not present in asymptomatic carriers or in patients with chronic persistent hepatitis. Testing of sequential samples revealed that the presence of IgM anti-HBc indicated active replication of HBV and at the same time an immune response to the virus. The relationship between IgM anti-HBc and the response to interferon (IFN) therapy was also studied. Results showed that IgM anti-HBc is a useful marker of the efficacy of interferon therapy.

Carrier State↗
PubMed1986

Protection against oxygen-induced reperfusion injury of the isolated canine heart by superoxide dismutase and catalase.

While oxygen-derived free radicals have been implicated in the pathogenesis of myocardial injury, the exact nature of this injury is still unclear. To test the hypothesis that oxygen-induced injury may influence the recovery of cardiac function from ischemic damage, we used an oxygen free radical scavenger, superoxide dismutase (SOD), together with catalase, during the reperfusion of isolated canine heart which had been subjected to 15 min of normothermic ischemic arrest followed by 2 hr of hypothermic cardioplegic preservation using a modified Collins solution. Determinations of thiobarbituric acid reactive substances and coenzyme Q10 within the myocardium showed that the treatment with SOD and catalase was capable of inhibiting lipid peroxidation induced by reperfusion. This inhibition was apparently associated with the improvement of myocardial energy metabolism and cardiac performance. Coronary flow was significantly higher in the heart treated with SOD and catalase during the working stage with a corresponding increase in oxygen consumption. Myocardial adenosine triphosphate (ATP) was partially, but significantly restored during reperfusion in these hearts whereas no restoration was observed in the heart without the enzymes. The treatment with SOD and catalase also improved left ventricular stroke work index and left ventricular maximum dp/dt at an early stage of the working mode. These results suggest that the use of SOD and catalase during reperfusion can protect the ischemic heart against reperfusion injury by scavenging oxygen-derived free radicals.

Animals↗
PubMed1986

Participation of bone marrow stromal cells in hemopoietic recovery of rats irradiated and then parabiosed with a non-irradiated litter mate. I. Light microscopic observations.

All rats were exposed to whole-body irradiation (1,000 rads by X-rays) to induce aplastic marrows. Control rats received no further treatment. Experimental rats were conjugated three days after irradiation with a non-irradiated healthy litter mate by aortic anastomosis. Control rats died within seven days due to irradiation injury. In these animals, bone marrow reticulum cells were easily distinguished from other stromal cells, such as macrophages or sinusoidal endothelial cells. Three to seven days after irradiation, reticulum cells accumulated lipid droplets in the cytoplasm and showed increases in size and number, resulting in fatty aplastic marrows. On the other hand, parabiosed rats showed hemopoietic recovery and lower levels of lipid droplets in reticulum cells at five to eight days after parabiosis. Progressive fibrosis followed after irradiation but a regression followed after parabiosis. This suggested that fibroblastoid reticulum cells aided in producing collagen fibers. It was also suggested that bone marrow stromal cells, namely, perisinusoidal and intersinusoidal reticulum cells, fat-storage cells, and fibroblastoid cells, shared a common cellular origin. The deserted alterations in reticulum cells after irradiation and the hemopoietic recovery after parabiosis might be due to hemopoietic cells stimulating reticulum cells to induce and sustain the hemopoiesis.

Anemia, Aplastic↗
PubMed1986

Participation of bone marrow stromal cells in hemopoietic recovery of rats irradiated and then parabiosed with a non-irradiated litter mate. II. Scanning and transmission electron microscopic observations.

A light microscopical study on the recovery process after lethal irradiation and parabiosis has been made. Electron microscopically, in the bone marrow of lethally irradiated rats, hemorrhage occurred due to detachment of sinus endothelial cells. Afterwards, reticulum cells with small intracytoplasmic lipid droplets appeared. On day 3, these cells were rapidly replaced by the reticulum cells with large lipid droplets, and resulted in fatty marrow within 7 days. Spindle-shaped fibroblastoid reticulum cells were also observed. In the bone marrow of lethally irradiated rats parabiosed with non-treated litter mates, hemopoiesis was initiated by adhesion of nucleated blood cells to intricate fine cytoplasmic pseudopods of fat-storage cells. On days 3 to 5, in parallel with progressive hemopoietic recovery, fibroblastoid and reticulum cells with large lipid droplets decreased whereas those with small droplets increased. On day 8, reticulum cells with lipid droplets were seldom seen, and hemopoietic distribution became the same as normal. These results suggested that bone marrow stromal cells, namely reticulum, fat-storage, and fibroblastoid cells share a common cellular origin, and also that they regain their structure and function when fat-storage cells were placed in contact with hemopoietic precursor cells.

Animals↗
PubMed1986

Garlic extract inhibits the enhanced peroxidation and production of lipids in carbon tetrachloride-induced liver injury.

Carbon tetrachloride (CCl4) enhances lipid peroxidation, resulting in triglyceride accumulation in the liver. In this report, we studied the therapeutic, but not the preventive, effect of garlic extract on CCl4-intoxicated liver, in comparison to the effect of vitamin E. Garlic extract was given orally to mice in the dose of 10, 100 or 500 mg/kg at 6 hr after CCl4 administration. The increased conjugated-diene level was diminished significantly to 82% by the 100 mg/kg extract, and also thiobarbituric acid-reactivity was inhibited by all the doses of the extract. In addition to the above mentioned effects, the high doses of garlic extract lowered hepatic triglyceride and lipid contents. Highly significant and positive correlation was observed between hepatic triglyceride content and conjugated-diene level in the lipid fraction of the liver. Besides, vitamin E at the dose of 25 mg/kg inhibited only lipid peroxidation. We, therefore, conclude that not only is garlic extract effective on diminution of lipid peroxide and on alteration of peroxidative status to more reductive condition like the effect of vitamin E, but it also inhibits hepatic triglyceride accumulation in injured liver.

Animals↗
PubMed1986

The role of marrow architecture and stromal cells in the recovery process of aplastic marrow of lethally irradiated rats parabiosed with healthy litter mates.

Bone marrow aplasia was induced in rats by whole body lethal irradiation (1,000 rads by x-ray), and rats died of irradiation injury within 7 days. Correlative studies at light (LM), transmission (TEM) and scanning electron microscopy (SEM) demonstrated swelling of endothelial and reticular cells and hemorrhage due to detachment of sinus endothelial cells on days 1 and 2. With time, structural recovery occurred without hemopoietic recovery. Reticular cells developed small intracytoplasmic lipid droplets on days 3 and 4. This resulted in fatty aplastic marrow within 7 days. On the other hand, in the marrow of irradiated rats parabiosed with healthy mates by aortic anastomosis, hemopoiesis was initiated by adhesion of nucleated blood cells to fine cytoplasmic pseudopods of fat-stored cells on days 1 and 2 after parabiosis. On days 3 to 5, reticular cells with large lipid droplets and fine pseudopods increased, then hemopoietic foci became clear and extensive. On day 8 after parabiosis, the aplastic bone marrow recovered completely both its structure and hemopoietic activity. Thus, hemopoietic recovery in lethally irradiated marrow begins with recovery of vascular endothelial cells, re-establishment of sinusoidal structure, and morphological and functional recoveries of reticular cells from fat-storage cells by releasing intracytoplasmic lipid droplets. Marrow stromal cells, namely reticular, fat-storage and fibroblastoid cells, share a common cellular origin, and regain their structure and function when fat-storage cells and fibroid cells are placed in contact with hemopoietic precursor cells.

Animals↗
PubMed1985

Composition of cholesterol esters in blood plasma of mouse, rat and rabbit.

Mixtures of cholesterol estes were extracted from the blood plasma of mouse (C3H/He, C57BL/6J and Jcl : ICR), rat (Wistar) and rabbit (JW-NIBS/Rabiton) and purified by thin-layer chromatography. Fatty acid moieties of the esters were methylated with BF3-methanol and analyzed quantitatively by gas chromatography. Although linoleate was most abundant (over 30% of the total esters) and myristate was found only in traces, the composition of the esters varied markedly among the species. Mice had 15.3 to 17.4% of arachidonate, but only a trace of linolenate and no stearate. In rats, arachidonate and linoleate were found in almost equal quantities, but stearate, linolenate and docosahexaenoate were present in only trace amounts. Rabbits had more palmitate and oleate and less arachidonate and eicosapentaenoate than the other two animals, but no docosahexaenoate.

Animals↗
PubMed1985

Relationship of Mallory bodies to intermediate filaments in hepatocytes. A scanning electron microscopy study.

Livers from 12 mice fed griseofulvin for 4 to 6 months were perfused in situ with a detergent solution to extract lipid membranes leaving the cytoskeleton intact. Seven control mice were similarly studied. After 30 to 120 minutes perfusion, liver samples were examined by scanning electron microscopy and transmission electron microscopy. By light microscopy, Mallory bodies (MBs) were observed in pericentral hepatocytes. These were confirmed by transmission electron microscopy. Intermediate filaments (IFs) were observed in close apposition to MBs. Numerous IFs were seen throughout the cytoplasm. The 3-dimensional organization of the cytoskeleton and MBs were clearly visualized by scanning electron microscopy. The IFs were disorganized in the hepatocytes and formed small MBs in griseofulvin-treated mice. In the case of hepatocytes containing large MBs, there was an apparent decrease in the concentration of IFs. Transition forms of dense networks of IFs between the normal cytoskeleton and the MBs were noted in the cytoplasm between small MBs and the nucleus and also at the cell border. The IFs connected to the nucleus and invaded the MBs. The MBs appeared to form as a result of condensation or collapse of the IFs.

Animals↗
PubMed1984

Laminar-related projection of primary trigeminal fibers in the caudal medulla demonstrated by transganglionic transport of horseradish peroxidase.

The mode of termination of primary afferent fibers within the cat trigeminal nucleus caudalis was investigated by means of the transganglionic transport of horseradish peroxidase (HRP). Several types of laminar-related labeling were observed, depending upon the survival time after HRP application. At the earliest survival time (28-34 h) the highest density of labeling was found in laminae I and II. At 2 and 3 days survival laminae III and IV were heavily labeled, in addition to laminae I and II where the amount of labeling was greatly increased in lamina I, but not in lamina II. At 5 days survival time an abrupt drop of labeling occurred in laminae I and II, while this pattern was not predominant in laminae III and IV. In lamina V the pattern of labeling was less intense and not changeable through all survival times observed. These findings indicating a differentiation of the primary afferent terminals have good correspondence with a functional specialization of neuronal locations since the functional properties of neurons vary according to their locations.

Animals↗