Biomedical subjects

Y Tashiro

Publications and source records attributed to Y Tashiro.

At least 73 records · Page 4Linked to original sources

PubMed1995

Quantitative immunoelectron microscopic analysis of the localization and induction of 25-hydroxyvitamin D3 24-hydroxylase in rat kidney.

25-Hydroxyvitamin D3 24(R)-hydroxylase (24-hydroxylase) is involved in the metabolism and regulation of vitamin D3 and is markedly induced by administration of vitamin D3. We detected this enzyme by electron microscopy and an immunogold technique along nephrons of normal and vitamin D3-administered rats. After the rats were administered vitamin D3, 50,000 IU/day for 1 week, they were perfusion-fixed with a paraformaldehyde solution. The fixed kidneys were then removed and embedded in LR White resin. Ultrathin sections were prepared and labeled by the immunogold technique using a mouse anti-rat 25-hydroxyvitamin D3 24-hydroxylase monoclonal antibody. We counted the number of gold particles bound per micron 2 of the mitochondria (particle density) of the tubule epithelial cells along the nephrons. In normal and vitamin D3-administered rats, gold particles were observed in the mitochondria of epithelial cells along the tubules. In normal rats, gold labeling for 24-hydroxylase was statistically significant (p < 0.05), in the S1-S2 segments, the S3 segment of the proximal tubules, and in the distal convoluted tubules. In the rats administered vitamin D3, the particle density increased significantly (p < 0.05) by about 12-fold in the S1-S2 segments of the proximal tubules, whereas it increased less markedly in other parts of the nephron. The marked induction of the S1-S2 segments of the proximal tubules suggests that these segments play an important role in the regulation of vitamin D3 metabolism.

Animals↗

PubMed1995

Expression and phosphorylation of BiP/GRP78, a molecular chaperone in the endoplasmic reticulum, during the differentiation of a mouse myeloblastic cell line.

To determine the functional significance of endoplasmic reticulum chaperones in hematopoietic cells, we analyzed the expression and post-translational modification of BiP/GRP78 and GRP94 as well as the cytoplasmic chaperones HSP70 and HSC70 during the differentiation of a mouse myeloid leukemia cell line, M1. The amounts of BiP/GRP78 and GRP94 increased several-fold when M1 cells were induced to differentiate into macrophage-like cells by treatment with interleukin-6 (IL-6). Synthesis began to increase at 4 hr after IL-6 treatment. The phosphorylated form of BiP/GRP78 increased during the later stages of differentiation. These data suggested that the chaperone activity of BiP/GRP78 and GRP94 may be needed for differentiated macrophage-like cells or for the differentiation event itself, and that functionally different BiP/GRP78 accumulate during the differentiation of M1 cells.

Animals↗

PubMed1995

Quantitative cryoimmunogold electron microscopic studies on induction of serine: pyruvate aminotransferase in rat liver mitochondria by administration of glucagon.

Induction of mitochondrial serine: pyruvate aminotransferase (SPT) in rat liver by administration of glucagon was studied quantitatively by immunoblot analysis and cryoimmunogold electron microscopy. Immunoblot analysis revealed that two daily injections of glucagon produced marked increase of SPT protein mass to a level as much as 18 times that of the untreated rat. Cryoimmunogold electron microscopic analysis showed that the labeling density of the mitochondria increased in a parallel manner. Thus the induction of SPT analyzed by two methods showed an excellent correlation with a relative correlation coefficient of 0.98, indicating that the induction of SPT can be analyzed quantitatively by immunogold electron microscopy on cryoultrathin sections.

Animals↗

PubMed1995

Stability, specific binding activity, and plasma concentration in mice of an oligodeoxynucleotide modified at 5'-terminal with poly(ethylene glycol).

Oligodeoxynucleotide (ODN) composed of 15 nucleotides was modified at 5'-terminal phosphate with hexylamine linker and chemically activated poly(ethylene glycol). This derivative showed improved characteristics in terms of enzymatic stability, binding activity, and in vivo retention in mouse. The data are discussed in comparison with those of corresponding unmodified and phosphorothioate ODNs.

Animals↗

PubMed1995

[Glioblastoma multiforme with liver metastasis--case report].

Extracranial metastasis of glioblastoma is rare. This is an autopsy case report of a patient with glioblastoma multiforme found to have metastasized to the liver. A 42-year-old woman was admitted with a chief complaint of headache. Physical and neurological examinations on admission showed no abnormalities. CT and MRI demonstrated a tumor in the left parietooccipital region with invasion into the subependymal area of the left lateral ventricular trig-one. A cerebral angiogram showed tumor staining in the same area. Subtotal tumor resection was performed uneventfully. The microscopic diagnosis was glioblastoma multiforme. Postoperatively, the patient underwent whole brain and local irradiation, and intra-arterial ACNU infusion therapy. One month later, she developed low back pain, probably due to spinal dissemination. Postmortem examination showed local recurrence of the tumor and subarachnoidal dissemination not only in the base of the skull but in the lower spinal cord. Tumor was also observed in the liver, but no lung or lymph node metastasis was detected. Metastasis to the liver in this patient is believed to have occurred via the anastomosis between the vertebral and portal venous system.

Adult↗

PubMed1995

[Stereotactic radiosurgery with the gamma knife for brain metastases in patients with lung cancer].

Between February 1992 and April 1993, six patients with lung cancer were treated with gamma knife radiosurgery for brain metastases. Five patients had adenocarcinoma, and one patient had small cell carcinoma. Two patients had solitary metastases, and four patients had multiple metastases. Twelve metastases were treated with the gamma knife (peripheral dose between 12 Gy and 25 Gy). After radiosurgery, three complete and eight partial responses were achieved, which resulted in an overall response rate of 92%. In two patients, histological studies showed that few viable cells were surrounded by necrosis. Neurological status improved in all patients, and none died of complications. However, four of six patients later developed new intracranial metastases outside the treatment field. These data suggest that radiosurgery with the gamma knife is effective against brain metastases in patients with lung cancer, especially when the lesions are deep in the brain.

Adenocarcinoma↗

PubMed1995

[Pulmonary malignant fibrous histiocytoma treated with cisplatin plus etoposide followed by surgery].

A 47-year-old woman was admitted to our hospital with a mass shadow in the upper lobe of the right lung. Undifferentiated carcinoma was diagnosed after transbronchial biopsy. Combination chemotherapy consisting of cisplatin and etoposide was given. After two cycles of chemotherapy, partial response was obtained, and surgery was done because there was no evidence of lymph node metastasis or distant metastasis. After successful surgery, malignant fibrous histiocytoma was diagnosed because histological examination revealed the typical storiform pattern and most tumor cells showed positive cytoplasmic staining for alpha 1-antitrypsin, alpha 1-antichymotrypsin, and CD68. No evidence of another primary lesion was found, so this tumor was thought to be a pulmonary malignant fibrous histiocytoma. Cisplatin and etoposide have synergistic effect in vivo, and this combination is widely used as a standard regimen for small cell lung cancer and other malignancies. It might also be effective against pulmonary malignant fibrous histiocytoma.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1994

A patient with malignant paraganglioma that simultaneously produces adrenocorticotropic hormone and interleukin-6.

BACKGROUND: To the authors' knowledge, there have been no reports describing a case of malignant paraganglioma that produces both adrenocorticotropic hormone (ACTH) and interleukin-6 (IL-6). METHODS: The clinical course and pathophysiology of a patient with Cushing's syndrome induced by ectopic ACTH syndrome caused by a cervical malignant paraganglioma with elevated plasma levels of IL-6 was investigated. RESULTS: Ultrasonography, computed tomography, and magnetic resonance imaging of the neck revealed the presence of a tumor around the area from which the blood sample that showed the highest levels of ACTH and IL-6 was obtained by selective catheterization. Immunohistochemical staining of the removed tissue demonstrated the presence of ACTH and IL-6 proteins in the tumor cells. Reverse transcriptase-polymerase chain reaction also revealed the existence of IL-6 mRNA in those cells. CONCLUSION: The malignant paraganglioma of ectopic ACTH syndrome may produce IL-6. The present investigation provides new observations concerning ectopic ACTH syndrome.

ACTH Syndrome, Ectopic↗

PubMed1994

Association of N-ethylmaleimide-sensitive factor with synaptic vesicles.

N-Ethylmaleimide-sensitive factor (NSF) mediates docking and/or fusion of transport vesicles in the multi-pathways of vesicular transport. NSF was highly expressed in brain and adrenal gland. Immunostaining of cerebellum with an anti-NSF monoclonal antibody showed that NSF is predominantly localized in the molecular layers and the glomeruli of the granule cell layers. This distribution coincided well with that of synaptophysin, a marker protein of synaptic vesicles. Purification and immunoprecipitation revealed that NSF is associated with brain synaptic vesicles. The present results suggest that NSF is associated with synaptic vesicles without Ca2+ influx.

Animals↗

PubMed1994

Transmembrane topology and sites of N-glycosylation of inositol 1,4,5-trisphosphate receptor.

To define the transmembrane topology of the inositol 1,4,5-trisphosphate receptor (InsP3R), we determined the subcellular location of the hydrophilic segment (residues 2463-2529 of mouse type 1 InsP3R) believed to be located at the luminal side of the endoplasmic reticulum (ER) in the six-transmembrane model but at the cytoplasmic side in the eight-transmembrane model. This hydrophilic segment includes two consensus sites for N-glycosylation (Asn-2475 and Asn-2503). We prepared an anti-peptide antibody against residues 2504-2523. Electron microscope immunocytochemical studies of mouse cerebellar Purkinje cells showed that binding of this antibody frequently occurs in the intracisternal space of the ER. We constructed three mutant receptors by site-directed mutagenesis of Asn to Gln (N2475Q, N2503Q, and N2475Q/N2503Q). By concanavalin A column chromatography of these receptors, we found that both Asn-2475 and Asn-2503 are glycosylated. These results indicate that residues 2504-2523, Asn-2475, and Asn-2503 are exposed to the ER lumen. We therefore propose that InsP3R has six membrane-spanning segments. Based on the transmembrane topology and subunit organization, we suggest that InsP3R is a member of the superfamily that includes the voltage- and second messenger-gated ion channels on the plasma membrane.

Amino Acid Sequence↗

PubMed1994

Serum gastrin levels following administration of omeprazole alone or in combination with pirenzepine.

Serum gastrin levels in 44 peptic ulcer patients (26 gastric ulcer patients and 18 duodenal ulcer patients) were determined after they had been treated with omeprazole (OPZ) (20 mg/day) alone or in combination with pirenzepine (PZP) (100 mg/day). Serum gastrin levels were measured before, as well as 2, 4, and 6 weeks after administration, and the changes were compared. The levels were significantly elevated (twofold) at 2 weeks of treatment in both the OPZ and OPZ plus PZP groups. In patients taking OPZ alone, the levels rose up to 6 weeks, while in those taking OPZ plus PZP the levels decreased at 4 and 6 weeks. At 4 weeks, serum gastrin levels in the OPZ plus PZP group were lower (although not significantly) than those in patients taking OPZ alone. In gastric ulcer patients, serum gastrin levels in the OPZ group were significantly elevated, while in the OPZ plus PZP group, these levels were only slightly, but not significantly elevated. There was no significant difference between the two gastric ulcer groups at any time. In duodenal ulcer patients, serum gastrin levels increased significantly at 2 weeks of treatment in both groups. At 4 weeks and thereafter, the serum gastrin levels remained significantly high in patients taking OPZ alone, while they decreased at both 4 and 6 weeks in patients taking OPZ plus PZP. Thus, serum gastrin levels in duodenal ulcer patients were markedly decreased by the addition of PZP.(ABSTRACT TRUNCATED AT 250 WORDS)

Drug Therapy, Combination↗

PubMed1994

Immunohistochemical study of mucin carbohydrates and core proteins in human ovarian tumors.

Many of the cancer-associated antigens recently have been identified as mucin antigens. However, there are no detailed studies describing the expression of carbohydrates and core proteins of mucin antigens in ovarian tumors. In this study we examined the expression of carbohydrate antigens, which are associated with the earliest steps in mucin glycosylation (Tn and sialosyl-Tn), and the expression of the mucin core protein antigens associated with the MUC1 gene product (mammary-type apomucin) and the MUC2 gene product (intestinal-type apomucin) in 123 ovarian epithelial (mucinous and serous) tumors. In normal ovarian tissues neither Tn, sialosyl-Tn, nor intestinal-MRP antigens (MUC2 gene product) were expressed, except for positive sialosyl-Tn staining of stromal capillaries, while the MUC1 gene product, DF3 antigen, was expressed in the cell apex of the germinal coelomic epithelium when it had plump, slightly elongated, or pseudostratified nuclei. In the benign adenomas Tn and sialosyl-Tn antigens were detected in a small number of mucinous adenomas and rarely in serous adenomas. In contrast, expression of both Tn and sialosyl-Tn antigens was observed in all the adenocarcinomas and in a considerable number of borderline malignancies. DF3 antigen was expressed in many benign serous tumors but not so frequently in benign mucinous tumors; however, it was frequently expressed in the adenocarcinomas and borderline malignancies of both mucinous and serous types. Intestinal-MRP antigen expression increased with the transition of the mucinous tumors from a benign to malignant state, although it was never detected in the serous tumors. Coexpression of DF3 and intestinal-MRP antigens was seen in borderline malignancies and carcinomas of the mucinous tumors. In conclusion, simultaneous expression of Tn and sialosyl-Tn antigens is a highly effective tumor marker in both mucinous and serous tumors of the ovary. Coexpression of DF3 and intestinal-MRP antigens may indicate the malignant potential of ovarian mucinous tumors.

Adenocarcinoma↗

PubMed1994

Alpha- and beta-cell function in obese Zucker (fa/fa) rats: a study with the isolated perfused pancreas.

1. The effects of various stimuli, including changes in glucose concentration, arginine, tyramine and noradrenaline, on insulin and glucagon secretion were investigated using isolated perfused pancreata of obese and lean male Zucker rats at 12 months of age. 2. In Zucker fatty rats, the insulin secretion rate was significantly (P < 0.01) higher than that of lean rats at all glucose concentrations tested (8.3, 16.7 and 1.4 mmol/l). However, the integrated insulin secretory response to raising the glucose concentration from 8.3 to 16.7 mmol/l was almost absent in these rats. The glucagon secretion rates were significantly lower at 8.3 and 1.4 mmol/l glucose (P < 0.001 for both), and in responses to 10 micrograms/ml tyramine and 0.1 mumol/l noradrenaline (P < 0.05 for both), in Zucker fatty rats. Integrated insulin and glucagon responses to 10 mmol/l arginine were identical in the two groups. 3. Histopathological and immunochemical studies revealed hyperplasia of beta-cells and scattered alpha-cells in the enlarged islets of Zucker fatty rats. 4. These results suggest that, in Zucker fatty rats, the decreased glucagon secretion in the isolated perfused pancreas is attributable to changes in the environment of alpha-cells and/or the inhibitory effects of hypersecreted insulin.

Animals↗

PubMed1994

Microsomal aldehyde dehydrogenase is localized to the endoplasmic reticulum via its carboxyl-terminal 35 amino acids.

Rat microsomal aldehyde dehydrogenase (msALDH) has no amino-terminal signal sequence, but instead it has a characteristic hydrophobic domain at the carboxyl terminus (Miyauchi, K., R. Masaki, S. Taketani, A. Yamamoto, A. Akayama, and Y. Tashiro. 1991. J. Biol. Chem. 266:19536-19542). This membrane-bound enzyme is a useful model protein for studying posttranslational localization to its final destination. When expressed from cDNA in COS-1 cells, wild-type msALDH is localized exclusively in the well-developed ER. The removal of the hydrophobic domain results in the cytosolic localization of truncated proteins, thus suggesting that the portion is responsible for membrane anchoring. The last 35 amino acids of msALDH, including the hydrophobic domain, are sufficient for targeting of E. coli beta-galactosidase to the ER membrane. Further studies using chloramphenicol acetyltransferase fusion proteins suggest that two hydrophilic sequences on either side of the hydrophobic domain play an important role in ER targeting.

Aldehyde Dehydrogenase↗

PubMed1994

ATP-dependent uptake of anti-neoplastic agents by acidic organelles.

Daunomycin, an anti-neoplastic agent, is known to be sequestered by acidic organelles in normal and multidrug-resistant cells [Willingham, M.C., Cornwell, M.M., Cardarelli, C.O., Gottesman, M.M., & Pastan, I. (1986) Cancer Res. 46, 5941-5946]. We studied the mechanism of accumulation of daunomycin into acidic organelles using chromaffin granule vesicles and proteoliposomes reconstituted with purified F-type H(+)-ATPase as model systems. Radiolabeled daunomycin was taken up by chromaffin vesicles upon addition of ATP. Its ATP-dependent uptake was stimulated about 1.4- to 1.8-fold by valinomycin plus K+, but was inhibited by ammonium chloride (10 mM) and nigericin plus K+. Quinidine (5 microM), verapamil (5 microM), or vanadate (0.5 mM), inhibitors of P-glycoprotein, had no effect on its uptake. Daunomycin was also taken up by liposomes reconstituted with F-type H(+)-ATPase. Furthermore, doxorubicin and vinblastine were taken up by these vesicles, whereas colchicine and rhodamine 123 were not. The accumulations of daunomycin and doxorubicin in acidic organelles of cultured cells were decreased by inhibiting vacuolar ATPase by addition of bafilomycin A1 or concanamycin A, or by increasing the internal pH by addition of nigericin. Melittin and N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide dissipated the delta pH and inhibited accumulation of daunomycin in the membrane vesicles and acidic organelles in cultured cells. These results indicate that the delta pH established by vacuolar-type ATPase drives the uptake of daunomycin, doxorubicin or vinblastine into acidic organelles, and that no specific transporters are involved in their uptakes.

Adenosine Triphosphate↗

PubMed1994

Visualization by an atomic force microscope of the surface of ultra-thin sections of rat kidney and liver cells embedded in LR white.

We visualized the surface of ultra-thin sections of rat liver and kidney embedded in LR White resin using an atomic force microscope. The section surface always showed depressions corresponding to the embedded cells at the plasma membrane, at the basal lamina, at mitochondria, and chromatin blocks in the nucleus. The depth of the depression corresponding to the plasma membrane was about 6 nm in both hepatocytes and several types of kidney cells. At the basal lamina, mitochondria, and the chromatin blocks, sections showed deeper depressions of about 10-30 nm. In addition, cytoplasmic surfaces showed strong relief, 3-4 nm on average. The surfaces of the resin block left after ultrathin sectioning showed protrusions corresponding to cells, mitochondria, and the chromatin blocks. In marked contrast, the surface of epon sections was much smoother than that of LR White sections, without showing any marked depressions and relief except for the chromatin blocks of the nucleus. The relation of the surface morphology of the ultrathin sections to the efficiency of immunolabeling is discussed.

Acrylic Resins↗

PubMed1994

Preferential localization of heat shock protein 47 in dilated endoplasmic reticulum of chicken chondrocytes.

We investigated the distribution of heat shock protein 47 (hsp47) in cultured chicken embryonic chondrocytes and epiphyseal chondrocytes of tibial bones from 1-day-old to 6-week-old chickens. Northern blot and immunoblot analyses revealed that hsp47 exists in epiphyseal cartilage and cultured chondrocytes. Confocal laser immunofluorescence microscopy showed that hsp47 was localized mainly in the many granular structures found in the cytoplasm that contain Type II collagen. Epiphyseal cartilage and cultured chondrocytes were embedded in LR White resin and hsp47 was detected by protein A-immunogold electron microscopy. Gold particles were localized exclusively in the cisternal space of the endoplasmic reticulum (ER), and the labeling density of the cisternal space of the dilated ER was always higher than that of the non-dilated ER. In all the differentiating zones of epiphyseal cartilage, the labeling density was highest in the hypertrophic cells. These findings suggest that hsp47 plays an important role(s) in the synthesis, processing, and assembly of Type II collagen.

Animals↗

PubMed1994

Immunocytochemical localization of Na, K-ATPase in rat muscle spindles.

In the muscle spindle, one of the major sensory receptors in the vertebrate skeletal muscle, it was demonstrated that stretching caused a conductance increase of the sensory terminal membrane mainly to Na+ (Hunt, Wilkinson and Fukami, 1978 (6)). Since the muscle spindle is a slowly adapting stretch receptor, and even at rest some spindles are active, a vigorous Na, K-pump activity is expected to counteract the incessant inflow of Na+ into the terminal. To test this assumption, rat muscle spindles were examined by immunofluorescence microscopy as well as by the electron microscopic immunogold technique using antibody against rat alpha-subunit of Na, K-ATPase. The results indicate that the sensory ending has the highest density of the enzyme among the other cellular components examined, and that the enzyme density appears to be higher in the plasma membrane of the sensory ending facing the intrafusal muscle fiber (synaptic membrane) than the rest of the membrane (extra-synaptic membrane). The functional significance of the above findings was discussed.

Animals↗