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Biomedical subjects

A Miyazaki

Publications and source records attributed to A Miyazaki.

At least 217 records · Page 12Linked to original sources
PubMed1988

Distribution of Ito cells in experimental hepatic fibrosis.

Ito cells (FSC) have been thought to be collagen-producing cells with regard to hepatic fibrosis. We have found that desmin, a structural protein of muscular intermediate filaments, is found in the cytoplasm of FSC, even in negative vitamin A-autofluorescence FSC, by using immunocytochemical techniques. In the present study, numbers of FSC produced by the administration of heterogeneic serum or carbon tetrachloride were detected in fibrous and non-fibrous areas of hepatic lobules by using a morphometrical analyser. After 8 weeks of intraperitoneal injections of heterogeneic serum into rats, FSC in fibrous septa increased in number and the increase continued to 12 weeks-although the numbers of FSC in non-fibrous areas and in controls given homologous serum did not change during the experiment. In the case of rats administered CCl4 once, FSC in fibrous areas increased in numbers after 48 h through 72 h, although the number of FSC in non-fibrous areas and in controls did not change. The results, with an apparent increase in numbers of FSC in fibrous areas and no change in non-fibrous areas, showed the possibility of hyperplasia due to cell division of FSC in the new fibroplastic areas.

Animals↗
PubMed1988

Bile canalicular contraction in the isolated hepatocyte doublet is related to an increase in cytosolic free calcium ion concentration.

Dynamic contractions of bile canaliculi have been observed in cultured doublet hepatocytes by means of time-lapse cinephotomicrography, and this contractile movement plays an important role in bile secretion. Although details of the mechanism are still unknown, the Ca2+-calmodulin system is believed to play a main role in this mechanism. In this study we measured the intracellular Ca2+ concentration of individual doublet hepatocytes using the Ca2+ indicator "fura 2" and microscopic fluorometry. We also observed the effects of A23187, norepinephrine and epinephrine on bile canalicular contraction and intracellular Ca2+ concentration. After loading 1 mumol/l fura 2 in doublet cells, we added A23187, epinephrine or norepinephrine and then measured the Ca2+ concentration in a given small area in the cytoplasm of individual doublet cell. A23187, norepinephrine and epinephrine caused a prompt increase of the intracellular Ca2+ concentration and also caused bile canalicular contraction. The present study indicates that the sudden increase of intracellular Ca2+ concentration causes bile canalicular contraction through the Ca2+-calmodulin system.

Animals↗
PubMed1988

Induction of insulitis by adoptive transfer with L3T4+Lyt2- T-lymphocytes in T-lymphocyte-depleted NOD mice.

To clarify the pathogenesis of insulitis in the nonobese diabetic (NOD) mouse, an animal model for human insulin-dependent diabetes mellitus, T-lymphocyte-depleted NOD mice (B mice) were adoptively transferred with spleen and lymph node cells from cyclophosphamide-treated NOD mice after separating the cells with monoclonal antibodies against various T-lymphocyte surface antigens plus complement. Light-microscopic and immunohistochemical studies were also performed to investigate the lymphocytic infiltrations. The incidence of insulitis detected in B mice was much lower when compared with that of the lesion naturally occurring in the NOD mouse. However, higher incidence of insulitis was inducible in B mice by transferring unfractionated lymphoid cells from NOD mice. When the Thy1+ cell-depleted fraction was transferred into the B mice, no increase in the incidence of insulitis was observed. The Lyt1+ or L3T4+ cell-eliminated fraction was also unable to transfer insulitis. Conversely, donor cells depleted of Lyt2+ components successfully induced insulitis in the recipient B mice. These data were consistent with the immunohistochemical study, which showed that the main phenotype of the cells infiltrating the islets was L3T4+. These results suggest the importance of L3T4+Lyt2- T-lymphocytes in the pathogenesis of insulitis in NOD mice.

Animals↗
PubMed1988

Histamine metabolism and pinnal hyperaemia during magnesium deficiency in rats.

The relation between histamine metabolism and an appearance of pinnal hyperaemia during magnesium (Mg) deficiency, and the effects of some factors on these were studied in 3-week-old Wistar rats. On a Mg-deficient diet (Mg 0.001%), the histamine concentrations in plasma and urine increased after 4-5 d, and reached a maximum after 6-12 d. Pinnal hyperaemia appeared during the same time course. The hyperaemia was reduced by the administration of antihistamines (cimetidine and diphenhydramine). These results indicate that pinnal hyperaemia during Mg deficiency is mediated by histamine. The administration of oestradiol benzoate (0.08 mg/100g body weight subcutaneously once a day for 8 d) and/or gamma-ray irradiation (600 rad/d before experiments) reduced the appearance of pinnal hyperaemia and the increment in the urinary histamine during Mg deficiency. The histamine content increased in the spleen and some tissues after 8 d, but not in the skin, with increasing the activity of histamine synthesis. The treatments mentioned above depressed the increment of histamine content. These results suggest that the pinnal hyperaemia and the increment of the urinary histamine in the Mg-deficient rat are related to the increment of both the histamine synthesis and release.

Amine Oxidase (Copper-Containing)↗
PubMed1988

Calmodulin antagonists inhibit the phagocytic activity of cultured Kupffer cells.

The mechanism of phagocytosis by Kupffer cells is still unknown. In this study we found that trifluoperazine, chlorpromazine, and W-7, drugs which bind to Ca2+-calmodulin and inhibit its interaction with other proteins, inhibit phagocytosis by cultured Kupffer cells using polystyrene beads, time-lapse VTR systems, and fluorescent staining techniques. Inhibitory effects of these drugs on phagocytosis suggests that the Ca2+-calmodulin system may be involved in this complex cellular function and the integrity of the cytoskeletal system of Kupffer cells is essential to this phenomenon.

Actins↗
PubMed1987

Expression of class II major histocompatibility complex antigens on pancreatic B cells in the NOD mouse.

To elucidate the role of class II major histocompatibility complex antigen expression on pancreatic B cells in the development of diabetes in the non-obese diabetic (NOD) mouse, indirect immunofluorescence was employed for I-A staining on Bouin-fixed pancreas sections of NOD mice (I-A of which was reported as d), B10.GD (I-A, d), BALB/c (I-A, d) and C3H/He (I-A, k). I-A positive islets were observed in all NOD mice examined. Positive reaction was detected in islets both with and without lymphocytic infiltrations. Double staining with anti-insulin, glucagon, somatostatin or pancreatic polypeptide antibodies revealed that I-A positive cells corresponded with insulin cells, while other types of pancreatic islet cells were virtually negative for I-A. Weaker staining was seen in islets of B10.GD and, to a lesser extent, in those of BALB/c mice. C3H/He mouse islet cells showed no I-A expression. These results demonstrated the expression of I-A antigens on pancreatic B cells in the NOD mouse.

Animals↗
PubMed1987

Gastric cancer with synchronous unresectable hepatic metastasis and a positive response to chemotherapy--report of two cases.

We report herein the clinical events seen in two longterm survivors of gastric cancer with unresectable synchronous hepatic metastases. Partial gastrectomy was performed against the primary lesion and continuous intra-arterial infusion of anti-tumor drugs, followed by prolonged systemic antitumor drug treatment, were prescribed. A 43-year-old man with moderately-differentiated tubular adenocarcinoma had an uneventful course during his first 21 postoperative months. However, multiple liver metastases became manifest at 24 months and enlargement of the intrahepatic foci led to death 27 months after gastrectomy. A 51-year-old woman with moderately-differentiated tubular adenocarcinoma had an uneventful postoperative course and is now well with no signs of recurrence 6 years and 6 months after gastrectomy.

Adult↗
PubMed1987

Effects of intracoronary infusion of arterial blood or Fluosol-DA 20% on regional myocardial metabolism and function during brief coronary artery occlusions.

Effects of intracoronary infusion (50 ml/min) of arterial blood, oxygenated or unoxygenated Fluosol, or Plasmalyte A on hemodynamics, electrocardiogram, regional myocardial function, and lactate metabolism were studied in six closed-chest dogs during 2 min occlusions of the left anterior descending coronary artery followed by 10 min of reperfusion. Normal hemodynamics were maintained with infusion of arterial blood and oxygenated Fluosol, whereas unoxygenated Fluosol and Plasmalyte A resulted in hemodynamic deterioration similar to that noted with no treatment. Ischemic zone systolic fractional area change, an index of systolic function measured by two-dimensional echocardiography, remained normal during the occlusion supplemented with intracoronary arterial blood (49 +/- 7%), was moderately hypokinetic with oxygenated Fluosol (31 +/- 10%), and became severely hypokinetic with unoxygenated Fluosol (14 +/- 14%), with Plasmalyte A (2 +/- 13%), and in the absence of treatment (5 +/- 9%). Only infusion of arterial blood resulted in no ST segment elevation or lactate production. Thus intracoronary infusion of arterial blood during brief coronary occlusion maintained normal myocardial function and aerobic metabolism. Infusion of oxygenated Fluosol resulted in amelioration of the decline in regional function after coronary occlusion, but not complete protection.

Angioplasty, Balloon↗
PubMed1987

[Long-term survival in an elderly patient with acute myeloblastic leukemia].

A 79-year-old patient with acute myeloblastic leukemia (M2 type in FAB), who has survived more than 5 years, is reported. She was admitted because of fever and anemia. Her white blood cell count was 6200/mm3 with 58% blasts. Bone marrow aspiration showed a nucleated cell count of 26 X 10(4)/mm with 84% blasts, Complete remission was achieved within one month by DCMP two-step method therapy. She relapsed in the third and fifth years after initial therapy. Because leukemic change is atypical, she was treated with a low dose of Ara-C therapy, resulting in complete remission. In cases of acute myelobastic leukemia in elderly patients, long-term survival is rare. However in this case, follow-up has succeeded for 5 years. This patient is the oldest case of acute myeloblastic leukemia ever reported in Japan.

Age Factors↗
PubMed1986

Ultrastructural and immunocytochemical aspects of lymphocytic submandibulitis in the non-obese diabetic (NOD) mouse.

The submandibular glands of female non-obese diabetic (NOD) mice (22-26 weeks of age) were studied by light and electron microscopy. Mononuclear cells consisting mostly of lymphocytes were recognized in and among the acini and secretory ducts. Some parts of the secretory ducts and mucous acini surrounded by lymphocytes showed destructive changes. In the secretory ducts lymphocytes invaded the duct epithelial lining and the duct lumen was occluded by these cells. The duct epithelial cells in such lesions were extremely distorted and tonofilament bundles running in various directions were present in the cytoplasm. Lymphocytes were in close contact with the duct epithelial cells. In the mucous acini some acinar cells, which appeared to be compressed by the infiltrating lymphocytes, showed degenerative changes. Immunocytochemical study revealed that both T- and B-lymphocytes were involved, T-lymphocytes tending to occupy the center of the infiltrate, while B-lymphocytes occupied the periphery. Although autoantibody against duct epithelial cells was identified, damage to duct epithelial cells was not correlated with the presence of this antibody. The morphological changes in the submandibular gland of the NOD mouse are very similar to those reported in the salivary gland of patients with Sjögren's syndrome.

Animals↗
PubMed1986

Elevated antibody-dependent cell-mediated cytotoxicity and its inhibition by nicotinamide in the diabetic NOD mouse.

Antibody-dependent cell-mediated cytotoxicity (ADCC) by splenic mononuclear cells was measured in female non-obese diabetic (NOD) mice and age-matched ICR mice. No significant difference in ADCC activities was observed between the two groups when all the NOD mice were pre-diabetic. ADCC activities in diabetic NOD mice were significantly higher than those in age-matched ICR mice (P less than 0.001). Nicotinamide, known to prevent the diabetes of the NOD mouse, strongly inhibited ADCC by the mononuclear cells from diabetic NOD mice. Kinetic studies revealed that the inhibition was non-competitive.

Animals↗
PubMed1986

Sex difference of pinnal hyperemia in magnesium-deficient rats: effects of castration and administration of sex hormone.

In the course of studies on the effects of magnesium (Mg) depletion in the diet (0.001% Mg) on mature rats (10 week-old), it became apparent that females developed less hyperemia than males. In the females, the time of onset and severity of hyperemia were enhanced by castration, but not in the males. These data suggest that the development of hyperemia in Mg-deficient adult rats depends on the female sex hormone. The effects of administration of estradiol were examined, using immature rats (3 week-old), in relation to hyperemia and histamine metabolism. Two to 3 days after feeding young male and female rats a Mg-deficient diet, the pinnal hyperemia appeared in the same degree. The hyperemia was reduced by the administration of estradiol benzoate (0.04-0.08 mg/100 g body wt. per day, s.c.) every day. The increments in urinary histamine excretion, splenic histamine content and histidine decarboxylase activity during Mg-deficiency were markedly reduced by the administration of estradiol. The sex difference in the hyperemia which appeared upon Mg-depletion depends on the effects of the female hormone, estradiol, on histamine metabolism.

Amine Oxidase (Copper-Containing)↗
PubMed1986

Hypercalcemia in glucocorticoid withdrawal.

We found severe hypercalcemia in the course of hydrocortisone withdrawal in a patient who had undergone unilateral adrenalectomy to resect a cortisol-hypersecreting adenoma. Serum calcium gradually but progressively increased after unilateral adrenalectomy. Severe hypercalcemia developed on the 77th postoperative day (the 15th day after discontinuing hydrocortisone replacement). The serum concentration of calcium, PTH, 25(OH)D, and 1,25(OH)2D were 8.0 mEq/l, less than 100 pg/ml, 10.1 ng/ml and 29.6 pg/ml, respectively. This hypercalcemia was accompanied by marked urinary hydroxyproline excretion and less calcium excretion in the urine than the prevailing level of serum calcium. Serum concentrations of 25(OH)D, 1,25(OH)2D and PTH were not elevated during the severe hypercalcemia. We concluded that the hypercalcemia in this patient was due in part to enhanced bone resorption and increased renal tubular reabsorption of calcium as a result of glucocorticoid withdrawal, but not to the elevation of serum PTH or serum 25(OH)D and serum 1,25(OH)2D.

Adenoma↗