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Biomedical subjects

A Masumoto

Publications and source records attributed to A Masumoto.

44 records · Page 3Linked to original sources
PubMed1991

Sequestration of a hepatocyte growth factor in extracellular matrix in normal adult rat liver.

Perfusion of normal adult rat livers with Hanks' solution containing 1 M NaCl in situ led to the releasing of a large amount of hepatocyte growth factor (HGF). During the first 5 min of perfusion, the HGF content of the perfusate reached a maximum level, while the LDH activity due to release from the cells was negligible. The liver HGF content did not decrease with age. The liver HGF content in rats injured by CCl4 injection decreased temporarily and then recovered rapidly to a normal level. These results indicate that HGF is sequestered in the extracellular matrix in the subendothelial space in normal adult rat liver and its effect will be either neutralized or potentiated by other local factors.

Animals↗
PubMed1991

Effect of insulin, glucagon or dexamethasone on the production of apolipoprotein A-IV in cultured rat hepatocytes.

We studied the effects of insulin, glucagon or dexamethasone on the production of apolipoprotein A-IV (apo A-IV) by cultured rat hepatocytes, using specific radioimmunoassay for rat apo A-IV. We also compared the effect of these hormones on the production of apo A-IV with those of albumin and apo A-I, reported previously. In the absence of hormones, apo A-IV and albumin in culture medium increased almost linearly for periods up to 24 h. The rates of accumulation of apo A-IV and albumin in the medium were 15.4 ng/mg cell protein per h and 1.2 micrograms/mg cell protein per h, respectively. The concentration of intracellular apo A-IV remained constant during the incubation. Insulin stimulated the production of albumin, but inhibited the production of apo A-IV dose-dependently. Glucagon inhibited the production of both albumin, and apo A-IV dose-dependently. Dexamethasone showed no significant effects on albumin production, but stimulated apo A-IV production. Thus, apo A-IV production in hepatocytes is regulated by several hormones with different effects on albumin production. The regulatory effects of these hormones on apo A-IV production were almost identical with the effects observed in a course of apo A-I synthesis, suggesting that the production of the two apoproteins are regulated by similar mechanisms.

Albumins↗
PubMed1991

Effect of insulin, glucagon or dexamethasone on the production of insulin-like growth factor I in cultured rat hepatocytes.

We studied the effect of insulin, glucagon or dexamethasone on the production of insulin-like growth factor I (IGF-I) by cultured rat hepatocytes. Hepatocytes were isolated from normal adult rat livers and cultured in MEM, as nearly confluent monolayers. In the absence of such hormones, IGF-I and albumin accumulated in the culture medium almost linearly for periods up to 24 hours with the accumulation rates of 140 mU/mg cell protein per hour and 1.2 micrograms/mg cell protein per hour, respectively. Cycloheximide (5 micrograms/ml) almost completely inhibited the accumulation of IGF-I and albumin in the medium. Insulin at concentrations over 10(-10) M significantly inhibited the production of IGF-I in spite of the increased production of albumin. Conversely, glucagon stimulated the production of IGF-I at concentrations over 10(-8) M, but inhibited the production of albumin at concentrations over 10(-10) M. Dexamethasone stimulated the production of IGF-I at concentrations over 10(-7) M, but had no significant effects on the production of albumin. Thus, IGF-I production of hepatocytes is regulated by several hormones with different manner from albumin production.

Animals↗
PubMed1989

Growth stimulation of adult rat hepatocytes in a primary culture by soluble factor(s) secreted from nonparenchymal liver cell.

Cocultures of adult rat hepatocytes with nonparenchymal liver cells (NPC) resulted in stimulation of DNA synthesis of hepatocytes and their survival for more than one month. These cells were found capable of synthesizing albumin and 3-methylcholanthrene-inducing cytochrome P-450. A conditioned medium obtained by culturing NPC was effective to the same degree as the coculture with NPC for stimulating DNA synthesis in hepatocytes. The factor(s) responsible for this was inactivated by heating or trypsin treatment, but it was not capable of passing through a cellulose tubing. It is thus evident that soluble proteinaceous substance (s) secreted from NPC stimulates the growth of hepatocytes in a primary culture.

Animals↗
PubMed1988

Effects of insulin, dexamethasone and glucagon on the production of apolipoprotein A-I in cultured rat hepatocytes.

Cultured rat hepatocytes were used to study the effects of hormones on the production of apo A-I. In addition, we compared these effects with the production of albumin. Hepatocytes were isolated from normal adult rat livers and cultured in MEM, as nearly confluent monolayers. In the absence of hormones, apo A-I and albumin accumulated in the culture medium almost linearly for periods up to 24 h. The rates of accumulation of apo A-I and albumin in the medium were 22 ng/mg cell protein per h and 1.2 micrograms/mg cell protein per h, respectively. During the incubations the cellular contents of apo A-I remained constant. Insulin stimulated the production of albumin at concentrations over 10(-10) M, but inhibited the production of apo A-I at concentrations over 10(-8) M. Dexamethasone showed no significant effects on albumin production but stimulated apo A-I production at concentrations over 10(-6) M. Glucagon inhibited the production of albumin and apo A-I dose-dependently at concentrations over 10(-10) M. Thus, the production of albumin and apo A-I are presumably controlled by different regulatory mechanisms.

Albumins↗
PubMedDate not supplied

Hematologic response in patients with aplastic anemia after long-term administration of recombinant human granulocyte colony-stimulating factor and erythropoietin.

Twenty patients with aplastic anemia underwent long-term administration (10 weeks) of recombinant human granulocyte colony-stimulating factor (rhG-CSF) in doses from 50 to 800 micrograms/m2 per day by intravenous infusion or 50 to 100 micrograms/m2 per day by subcutaneous injection and re-combinant human erythropoietin (rhEPO) in doses ranging from 2000 to 8000 IU/m2 per day by intravenous injection three times a week for at least 4 weeks. The goal was to evaluate whether therapy ameliorated pancytopenia in these patients as well as to determine its safety. All assessable patients showed a substantial increase in absolute neutrophil count, with a recovery of myeloid components (granulocyte series) in the bone marrow, after 2 to 10 weeks of treatment. An increase > 1.5 g/dL in hemoglobin (Hb) concentration was observed in 2 patients (10%). A decrease > 50% in red cell transfusion requirement was observed in 2 patients (10%). Seven patients showed recovery of neutropenia, anemia, and platelet count. In addition, there was no serious infection before or during therapy, and side effects were mild. Of the 20 patients, 3 showed a dramatic improvement in severe anemia after 10 weeks of treatment accompanying a recovery of erythroid components in the bone marrow. They no longer require red cell transfusions and have had normal Hb concentrations and normal ferrokinetics. These results indicate that long-term administration of rhG-CSF and rhEPO may benefit some patients with aplastic anemia. Further studies will be necessary to elucidate the mechanism by which rhGCSF and rhEPO stimulate hematopoiesis and improve hematologic abnormalities in these patients.

Adolescent↗
PubMedDate not supplied

Clinical significance of the serum levels of the 7S domain of type IV collagen in patients with primary biliary cirrhosis.

The serum levels of the 7S domain of type IV collagen were measured with a radio-immunoassay in 42 patients with primary biliary cirrhosis (asymptomatic: n = 28; symptomatic: n = 14), 10 patients with chronic active hepatitis, 10 patients with liver cirrhosis and 10 healthy female controls. Serum levels of the 7S domain of type IV collagen were: 4.28 ng/mL (3.88-4.72 ng/mL; mean and range of mean +/- s.d.) in healthy controls; 5.97 ng/mL (5.07-7.02 ng/mL) in patients with chronic active hepatitis; 8.23 ng/mL (6.40-10.58 ng/mL) in patients with liver cirrhosis; and 6.79 ng/mL (4.76-9.67 ng/mL) in patients with primary biliary cirrhosis. Patients with liver cirrhosis and primary biliary cirrhosis had higher levels of serum 7S domain of type IV collagen than healthy controls (P < 0.001, respectively). Serum levels of the 7S domain of type IV collagen in patients with asymptomatic primary biliary cirrhosis, 5.83 ng/mL (4.55-7.48 ng/mL) were significantly lower than those in symptomatic primary biliary cirrhosis, 9.18 ng/mL (6.53-12.91 ng/mL; P < 0.001). Serum levels of the 7S domain of type IV collagen increased significantly along with advancement of the histological stages of primary biliary cirrhosis. Serum levels of the 7S domain of type IV collagen in the paired sera of eight patients with asymptomatic primary biliary cirrhosis (mean interval 30 months, range 12-48 months) showed significant rises during the intervals (P < 0.05), while serum levels of albumin and total bilirubin did not change significantly during these intervals.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomarkers↗