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Biomedical subjects

M Yoshitake

Publications and source records attributed to M Yoshitake.

At least 55 records · Page 3Linked to original sources
PubMed1995

Effects of extracellular matrices on tube formation of cultured rat hepatic sinusoidal endothelial cells.

To determine the effects of extracellular matrices on the function and morphology of hepatic sinusoidal endothelial cells, isolated rat hepatic sinusoidal endothelial cells were cultured in three-dimensional fashion on collagen gel containing various extracellular matrix components. Cells cultured on type I collagen gel with or without type IV collagen formed a cobblestone appearance on the surface of the gel. Cells cultured on laminin-containing type I collagen gel invaded the gel and exhibited three-dimensional tube formation with a decreased number of characteristic endothelial pores. Morphometrically, there was a significant relationship between the length of the tube formed and the concentration of laminin in the type I collagen gel. Cells cultured on Matrigel, which contains high concentrations of laminin, type IV collagen, fibroblast growth factor, tissue plasminogen activator, and other growth factors, formed a great number of tubes into a network on the surface of the gel, as is observed in the situ hepatic sinusoidal endothelial cells. Ultrastructurally, tube-forming endothelial cells cultured on Matrigel had many endothelial pores on the cell surface, with tubes (approximately 10 microns in diameter) formed by two or three hepatic sinusoidal endothelial cells. These results indicated that extracellular matrix components, especially laminin, induced the formation of tubes in cultured rat hepatic sinusoidal endothelial cells. Tube-forming sinusoidal endothelial cells cultured on Matrigel could provide more advantages than the two-dimensional culture model for investigating the function and morphology of these cells in vitro.

Animals↗
PubMed1994

Tubulovesicular transport of horseradish peroxidase in isolated rat hepatocyte couplets: effects of low temperature, cytochalasin B and bile acids.

The transcytotic vesicular pathway in isolated rat hepatocyte couplets was investigated using horseradish peroxidase. Ten to 20 min after horseradish peroxidase labeling, vesicles and tubules containing horseradish peroxidase were observed to be predominantly around the bile canaliculi. In hepatocytes incubated in a 4 degrees C medium for 10 min after horseradish peroxidase labeling, few horseradish peroxidase-containing structures were observed around the bile canaliculi, and the fine reticular immunofluorescence of microtubules was reduced. Cells treated with cytochalasin B (a microfilament inhibitor) showed a fair number of horseradish peroxidase-containing structures around the markedly dilated bile canaliculi and the distribution of microtubules was preserved. Cells labeled by horseradish peroxidase and then incubated for 10 min in a horseradish peroxidase-free medium containing 50 mumol/L of taurocholic acid, ursodeoxycholic acid or tauroursodeoxycholic acid had more tubular structures containing horseradish peroxidase around the bile canaliculi than control cells, whereas 50 mumol/L of taurochenodeoxycholic acid, taurodeoxycholic acid, dehydrocholic acid and taurodehydrocholic acid each failed to increase the number of tubular structures. These findings show that horseradish peroxidase was transported in hepatocyte couplets from the cell periphery to the bile canalicular front through the tubulovesicular pathway, depending on cytoplasmic microtubules. Cytoplasmic microfilaments appeared to play a minor role in this transport. Several specific bile acids such as taurocholic acid, ursodeoxycholic acid and tauroursodeoxycholic acid each promoted the tubular transformation.

Animals↗
PubMed1994

Ultrastructure of the intracellular membranous system of rat hepatocytes in intrahepatic cholestasis induced by phalloidin.

To investigate the effect of a thickened pericanalicular ectoplasm in tubulovesicular transport and biliary excretion, we examined the ultrastructure of the intracellular membranous system in rat hepatocytes with and without phalloidin treatment, by transmission electron microscopy and scanning electron microscopy combined with the Aldehyde prefix Osmium-Dimethyl Sulfoxide-Osmium method. Hepatocytes possessed elaborate networks of tubules around bile canaliculi, and some of them extended to the bile canaliculi in control rats. Vesicles were also present around the bile canaliculus. Treatment of rats with phalloidin produced a thick pericanalicular ectoplasm around the bile canaliculus visualized by transmission electron microscopy, and the density of vesicles (p < 0.001) and tubules (p < 0.001) within 0.5 microns around the bile canaliculus significantly decreased in phalloidin-treated rats. The number of lysosomes in hepatocytes apparently increased in phalloidin-treated rats; however, they were rarely observed around the bile canaliculus. The Aldehyde prefix Osmium-Dimethyl Sulfoxide-Osmium method produced an organelle-free space around the bile canaliculus by removing the thick pericanalicular ectoplasm in scanning electron microscopic examination, and the thickened pericanalicular ectoplasm inhibited the approach of intracellular membranes to the canalicular membrane in the transmission electron microscopic examination. In some pathological cholestatic conditions, the thickened pericanalicular ectoplasm may inhibit not only bile canalicular contraction but also biliary excretion of substances, which is mediated by the tubulovesicular transport system.

Animals↗
PubMed1994

Vitamin C reduces ischemia-reperfusion injury in a rat epigastric island skin flap model.

Free radicals have been implicated in the cause of ischemia-reperfusion injury. Various agents have been used in an attempt to reduce ischemia-reperfusion injury pharmacologically, including free radical scavengers. Vitamin C (ascorbic acid), a well-known free radical scavenger, has not, to the best of our knowledge, been evaluated in this respect. Previous work at our institution has shown that vitamin C decreases capillary permeability, thus significantly reducing fluid resuscitation requirements in postburn cases. Because this is due in part to the scavenging effect of vitamin C on free radicals, we investigated the role, if any, of vitamin C on ischemia-reperfusion injury in a rat epigastric island skin flap model. Twenty-four adult Sprague-Dawley rats were divided into control and vitamin C groups. Superficial epigastric island skin flaps measuring 6.0 x 3.5 cm were raised. Pedicles were isolated and occluded with microvascular clamps for 6 hours. The flaps were then sutured back to their beds over Steri-Drape barriers. Fifteen minutes before reperfusion, the control group flaps were perfused via femoral artery cannulation with normal saline (2.5 ml/kg). The vitamin C-treated group was perfused in a similar fashion with 2.5 ml/kg of a vitamin C/normal saline solution (27 mg/ml). The animals were observed for 7 days, and the percentage of flap survival was determined using a paper template technique. The vitamin C-treated group demonstrated a significantly higher percentage of flap survival than did the control group (25.8% mean vs. 7.5% mean, p < 0.025). In this animal model, vitamin C reduced or limited reperfusion injury after 6 hours of ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

A miniunit approach to lip reconstruction.

Aesthetic units of the face have been described previously. Burget applied the subunit principle to upper lip reconstruction. When defects are too small to replace subunits, we have employed a miniunit approach for their closure. When potential or actual wrinkle lines, as well as contour subunit lines, are used in flap design, miniunit flaps can be created which improve the aesthetic results. Symmetry, normal contour, preservation of normal layered muscular anatomy, and unnoticeable scars are attainable. Included herein is a description and evaluation of the advantages of this principle.

Adult↗
PubMed1994

Asialoglycoprotein receptor function of hepatocytes in patients with autoimmune hepatitis.

To assess whether the hepatocyte asialoglycoprotein receptors are affected in patients with autoimmune hepatitis, the function of the hepatocyte asialoglycoprotein receptor was investigated in patients with autoimmune hepatitis or chronic hepatitis C. A new radionuclide liver imaging technique, Technetium-99m diethylenetriamine-pentaacetic acid-galactosyl human serum albumin, was applied to evaluate the function of the receptor. A Receptor Index (LHL 15) was calculated by dividing the radioactivity of the liver region-of-interest (ROI) by that of the liver plus heart ROI 15 min after radiolabeled ligand injection. Serum albumin, prothrombin time, hepaplastin test and plasma retention rate of indocyanine green at 15 min were not significantly different between patients in the autoimmune hepatitis group and chronic hepatitis C group. In addition, the Receptor Index of patients with autoimmune hepatitis, in whom the asialoglycoprotein receptor is a candidate target antigen for autoimmune response, was similar to that of patients with chronic hepatitis C. These results indicate that the hepatocyte receptor for asialoglycoproteins is not affected in patients with autoimmune hepatitis.

Adult↗
PubMed1994

Function of asialoglycoprotein receptor of hepatocytes in patients with Wilson's disease.

The function of hepatocyte asialoglycoprotein receptors was analyzed in normal subjects, in patients with Wilson's disease and in patients with chronic hepatitis C. A new radionuclide liver imaging, using Technetium-99m diethylenetriamine-pentaacetic acid-galactosyl human serum albumin, was applied to evaluate the function of the receptor, and a Receptor Index, LHL 15, which was calculated by dividing the radioactivity of the liver region-of-interest (ROI) by that of the liver plus heart ROI at 15 min after the radiolabeled ligand injection, was evaluated. The values were similar between the patients with Wilson's disease and patients with chronic hepatitis C. Hepatocyte receptors for asialoglycoproteins were not affected specifically in patients with Wilson's disease, suggesting that the defect in patients with Wilson's disease involves steps other than receptor-mediated endocytosis of asialoceruloplasmin via asialoglycoprotein receptor.

Adult↗
PubMed1994

[Investigations of the use of IABP during open heart surgery].

Since 1977, IABP has been employed in 180 cases. We studied 94 adult patients who underwent open heart surgery and were treated with IABP procedure for the past 10 years, and investigated the following items, the timing of IABP initiation, preoperative left heart functions, aortic clamping time, period of IABP use, and mortality. Additional, P-V loop was measured during the operation. The following conclusions were drawn. When IABP was used preoperatively in cases with deteriorated cardiac functions, the incidence of in cases in which IABP was used during or after the operation. P-V loop is useful to obtain the detail of cardiac function which provides sufficient patient management during and after the operation, and could be useful for establishing the criteria of IABP use.

Adult↗
PubMed1993

Sarcoidosis accompanied by pancreatic impairment.

A 64-year-old male complained of weight loss and slight fever. Bilateral hilar lymphadenopathy and hepato-splenomegaly were observed. Serum ACE level was high, and liver function was impaired. Laparoscopy demonstrated small white nodules on the liver surface. A definite diagnosis of sarcoidosis was made by histological study of the specimen by liver biopsy and noncaseating epithelioid cell granulomas composed of giant cells and epithelioid cells were revealed. Various pancreatic enzymes were increased on admission, suggesting pancreatic impairment due to sarcoidosis. Corticosteroid therapy improved liver and pancreatic functions and decreased splenomegaly. He has been followed up for 4 years and 5 months.

Humans↗
PubMed1993

Erythropoietin production in hepatocellular carcinoma cells associated with polycythemia: immunohistochemical evidence.

Patients with hepatocellular carcinoma sometimes have erythrocytosis and high plasma erythropoietin levels. However, previous studies have not revealed direct evidence that the carcinoma cells produce the erythropoietin. To address this question, we carried out light and electron microscopic immunohistochemical studies, using a human erythropoietin antibody to the liver in three male patients with hepatocellular carcinoma and erythrocytosis. alpha-Feto-protein localization was also examined in serial liver sections by light microscopic immunohistochemistry with an antibody to alpha-fetoprotein. All three patients demonstrated high hemoglobin levels (16.7, 17.6 and 18.1 gm/dl) and high plasma erythropoietin levels (227, 266 and 280 mU/ml). In one patient the plasma erythropoietin level in the hepatic vein was significantly higher than that in the hepatic artery. The levels of plasma erythropoietin, as well as such tumor markers for hepatocellular carcinoma as serum alpha-fetoprotein and plasma des-gamma-carboxyprothrombin, were significantly reduced after treatment with an anticancer drug, cisplatin. Light microscopic immunohistochemistry showed that erythropoietin was definitely present in the cytoplasm of the hepatocellular carcinoma cells, but not in normal hepatocytes around the carcinoma lesion or in other nonparenchymal cells such as vascular endothelial cells and Kupffer cells. In electron microscopic immunohistochemistry, reaction products for erythropoietin were revealed in the cisternae of the endoplasmic reticulum in the carcinoma cells, suggesting the production of erythropoietin by these cells. Light microscopic immunohistochemistry showed that alpha-fetoprotein was localized in the hepatocellular carcinoma cells that were erythropoietin positive in the serial sections. These findings indicated that hepatocellular carcinoma cells produced erythropoietin as well as alpha-fetoprotein in these cases, leading to the complication of erythrocytosis.

Aged↗
PubMed1993

Biliary copper excretion in acutely and chronically copper-loaded rats.

Biliary copper excretion was examined in rats with acute, continuous and chronic copper loads. Copper was excreted into bile, and the concentration peaked 40 min after a venous injection of copper sulfate (127 ng/gm body weight). The excretion was significantly inhibited by colchicine. Therefore some copper may be transported in hepatocytes by a vesicular pathway and excreted into bile. Biliary copper output increased over time and reached a plateau 180 min after a continuous venous infusion of copper sulfate (318 ng/gm body weight/hr) had started, when the concentration of copper in bile was much higher than that in plasma; the bile/plasma ratio of copper concentrations was 4.32 +/- 0.46. These data support the idea that copper transport involves a specific uptake and transport system. In chronically copper-loaded rats, hepatic copper content was significantly increased compared with controls, and reaction products for copper were observed in hepatocyte granules by light microscopic examination with p-dimethylaminobenzylidene rhodanine stain. The number of lysosomes in hepatocytes increased and the shape changed. In chronically copper-loaded rats the number of tubular lysosomes was very high. However, other organelles appeared to be normal. In these rats biliary excretion of not only copper but also acid phosphatase, a lysosomal enzyme, was significantly greater than the control. Therefore hepatocyte lysosomes may play an important role in biliary copper excretion. Furthermore, when biliary lysosomal excretion increases, the tubular lysosomes actively participate in this excretion.

Acid Phosphatase↗
PubMed1992

Changes in blastogenic responses of lymphocytes and delayed type hypersensitivity responses after vaccination in dogs.

To clarify the immunologic effects of vaccination in dogs, we monitored total leukocyte and lymphocyte counts, humoral antibody responses, blastogenic responses of lymphocyte, and delayed type hypersensitivity (DTH) responses after vaccination. Mixed vaccines were administered on day 0 except for canine parvovirus (CPV) vaccine which was readministered on day 21. The puppy and adult dogs had a significant decrease in leukocyte and lymphocyte counts on day 7. The puppies showed a significant increase in the blastogenesis of lymphocytes after each vaccination, whereas the adult dogs had no significant changes. However, the adult dogs were divided into two groups, high responders and low responders in blastogenesis of lymphocytes. The dogs with higher or lower response in SI values on day 0 tended to show decrease or increase after the first vaccination, respectively. Since almost all dogs developed high titers of humoral antibody, it is considered that vaccination acts in an immunomodulative fashion. DTH responses to phytohemagglutinin (PHA) and CPV vaccine monitored at 0, 3, and 8 weeks after the first vaccination produced strong reactions, in particular those to CPV vaccine rose significantly after vaccination and maintained the higher responses for at least 2 months. These results suggest that DTH responses to PHA and CPV vaccine are helpful to monitoring non-specific and specific immune functions in vivo, therefore, DTH could be used as simple and rapid immunologic tests in canine practice.

Animals↗
PubMed1992

Ultrastructure of intracellular membranous system and intracellular transport of asialoglycoproteins in rat hepatocytes.

The ultrastructure of the intracellular membranous system in rat hepatocytes was observed three dimensionally with a scanning electron microscope using the aldehyde prefix osmium-dimethyl sulfoxide-osmium method. Intracellular organelles were clearly observed in three dimensions, and direct connection of tubular structures with the bile canalicular membrane was clearly seen. The transcellular pathway of asialoglycoproteins in isolated cultured rat hepatocytes was also investigated, by affinity cytochemistry, using gold-conjugated asialofetuin, under a transmission electron microscope. Gold particles were clearly seen not only in vesicles, endosomes and lysosomes, but also in the tubular structures. These results suggest that the tubular structures in rat hepatocytes directly participate in the transcellular transport of macromolecules. In addition, the frequent connections of tubular structures with the bile canalicular membrane indicate that these structures around the bile canaliculus may supply membrane components to the bile canalicular membrane.

Animals↗
PubMed1992

The antecubito-radial flap for the repair of forearm defect.

The antecubito-radial flap based on the inferior cubital artery via radial artery had been transposed to the forearm defect. Through the flow of this flap is normal at cubital and that of radial vessels retrograde, good results have been obtained. Advantage of this flap was discussed in relation to the radial forearm and the antecubital flap.

Forearm↗