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Biomedical subjects

T Tanabe

Publications and source records attributed to T Tanabe.

At least 433 records · Page 24Linked to original sources
PubMed1990

Protective effects of adrenoceptor-blocking agents on myocardial injury induced by epinephrine in mice.

Employing propranolol as a non-selective beta-blocker, atenolol, acebutolol and metoprolol as selective beta 1-blockers, butoxamine as a selective beta 2-blocker, labetalol as an alpha- and beta-blocker, and phentolamine as an alpha-blocker, we compared the effects of these adrenoceptor-blocking agents to reduce the degree of the myocardial injury induced by epinephrine in mice. Epinephrine in a single dose of 4 mg/kg/day, s.c., daily for 7 days, caused widely extended lesions, necrosis and fibrosis in the myocardial fibers, and degeneration in the residual myocardial fibers. The adrenoceptor-blocking agents in a dose of 10 mg/kg/day, s.c., given 30 minutes prior to epinephrine to each mouse daily for 7 days, had reduced the degree of the myocardial injury induced by epinephrine. The blockers, all, effectively suppressed the injury. Although metoprolol and butoxamine were less effective on the protection of the cardiotoxicity than phentolamine, the other blockers prevented the cardiotoxicity with the same degree as phentolamine did. These findings suggest that not only alpha- but also beta 1- and beta 2-adrenoceptors play critical roles in producing the myocardial injury.

Adrenergic alpha-Antagonists↗
PubMed1990

[An autopsy case of complicated form of spastic paraplegia with amyotrophy, mental deficiency, sensory impairment, and parkinsonism].

An autopsied case of complicated form of spastic paraplegia with many unusual clinical and pathological features is reported. Present case: a 31-year-old male. His parents are first cousins. Pregnancy and delivery had been unremarkable. Though he was mentally retarded, his physical development was normal. He was considered normal until age 10. He suffered from progressive disturbance in gait at the age of 11. He could not walk without assistance at the age of 22. Neurological examination revealed the following findings. He was obese and mentally deteriorated. Spastic paraplegia with increased tendon reflexes and pathological reflexes was prominent. Though slight sensory disturbance was present in the lower extremities, neither involuntary movement nor cerebellar ataxia was observed. In the age of late 20's, dementia, general muscular atrophy, and Parkinsonism developed. At the age of 30, he could not move by himself. He was apathic and indifferent, and showed forced laughing. Muscle tonus was flaccid because of general muscular atrophy and peripheral neuropathy. He died of acute gastric enlargement. Neuropathological findings were characterized by mal-development of the central nervous system (CNS) and the multisystem degeneration. There existed cerebral white matter hypoplasia with hypogenesis of the corpus callosum and ectopia of neurons of the cerebral and cerebellar cortex. Hypoplasia of melanin pigment was also observed in the remaining neurons of the substantia nigra and the locus ceruleus. Many neurons in the CNS included lipofuscin granules of variable shapes. Some of them showed clusters of several block-like inclusions which were green with luxol fast blue and cresyl violet stain.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Isolation of Staphylococcus hyicus subsp. hyicus from pigs affected with exudative epidermitis and experimental infection of piglets with isolates.

Five strains of Staphylococcus hyicus subsp. hyicus were isolated: three strains (P-1, P-2 and P-3) from the crust on the body surface of 6-month-old pigs on a farm in Aomori prefecture, and two (P-5 and P-6) from both the crust on the body surface and the joint of a 1-month-old piglet with exudative epidermitis (EE) on another farm. The characterization of the isolates and the experimental infection of the piglets with strain P-1 were carried out. Subcutaneous inoculation with the bacterial suspension (10(10) CFU) produced EE to all nine piglets. Eight of them had exudation and exfoliation within 24 hr of infection. Histopathologically, disappearance of stratum corneum and necrosis with vacuolar degeneration of prickle cells were remarkable in the epidermis. Infiltration of neutrophils and lymphocytes were observed in the dermis. The results clearly indicate that S. hyicus is responsible for incrustation of the body surface of weanling pigs and exudative epidermitis in young piglets.

Animals↗
PubMed1990

[Study of the fine structure of human deciduous dentin with dentinogenesis imperfecta, with special reference to the mantle dentin].

A lower deciduous incioer exhibiting dentinogenesis imperfecta (D.I) obtained from a 6-year-old boy with osteogenesis imperfecta (Shields' Type I) was examined by means of light microscopy (LM), scanning electron microscopy (SEM), and X-ray microanalysis (XMA). With LM, the dentin displayed a sparse and irregular tubular pattern near the dentino-enamel junction (DEJ) and only few or no tubular structures in the area corresponding to the circumpulpal dentin. Between these two areas, cleft-like structures were characteristically noted. Structural irregularities in the dentinal tubules were also shown with SEM observation. XMA demonstrated that the distribution of both Ca and P in the dentin of DI teeth was apparently lower than that in the normal deciduous incisor used as a control. Specifically, an area along EDJ at a distance of 25-35 microns, corresponding to the mantle dentin, revealed extremely low or no distribution of the both elements. From the present observation, it is suggested that the generic disorder mainly involved in the primary odontoblasts and consequently results in the disturbance of calcification, especially that mediated by the matrix vesicles, and shortening of the cell life. After the death of these cells, the cells originate in, from the undifferentiated pulp cells may participate in the deposition of another irregular dentin.

Calcium↗
PubMed1990

Gene structures of three vertebrate adenylate kinase isozymes.

Adenylate kinase is an ubiquitous enzyme which contributes to homeostasis of adenine nucleotide composition in the cell. In vertebrates, three isozymes (AK1, AK2, and AK3) are characterized which have distinct distribution in tissues as well as subcellular compartments. The genetic backgrounds of these adenylate kinase isozymes were analyzed. cDNA clones for AK1 were isolated from poly(A)+RNA of chicken skeletal muscle. The results of mRNA analysis in various tissues using the AK1 cDNA indicated that the AK1 gene expression is regulated both tissue-specifically and developmentally at the transcriptional level. The AK1 gene was cloned from chicken and human DNA and characterized. Both genes were split into seven exons. The intron positions in both genes coincided. cDNA clones for AK2 isolated from bovine liver poly(A)+RNA contained two types. One type (AK2A) encoded the same amino acid sequence as that reported for bovine heart AK2. The other type (AK2B) encoded the same sequence as AK2 except for the COOH terminus. The mRNA species corresponding to the two cDNA clones were identified in bovine liver and heart. Both the cDNA sequences were found to direct the active adenylate kinase synthesis in E. coli. The AK2 gene was cloned and characterized. It consisted of seven exons and six introns. From genomic structure analysis, the two cDNA species were shown to be derived from a single gene by the alternative splicing mechanism. Three types of cDNA clones for AK3 were isolated from bovine liver poly(A)+RNA, which contained the common AK3-coding region and different 3' portions. No NH2-terminal presequence of mitochondrial targeting was identified in AK3 from the sequencing and expression analyses of the cDNA. Upon expression of the cDNA sequence in E. coli, AK3 protein was recovered in the periplasmic space of the bacteria, indicating that AK3 without presequence was exported through the inner bacterial membrane as it is imported through the mitochondrial membranes. Internal targeting signals may be responsible for the translocation process. The AK3 gene was cloned and partially characterized. It is split into at least five exons. The comparisons of amino acid sequences and genomic structure of three isozymes revealed that a segment corresponding to either exon 5 of the AK2 gene or a part of exon 3 of the AK3 gene is missing in the AK1 gene. Phylogenetic analysis suggested that AK1, a shorter molecule, would have been separated from a longer molecule very early in evolution of adenylate kinase.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenylate Kinase↗
PubMed1990

[Mechanism of reduction in proteinuria by cyclosporine A: effects on the glomerular anionic sites].

To consider the mechanism of reduction of proteinuria by cyclosporine A (CYA) in the patient with intractable nephrotic syndrome, the effect of CYA on proteinuria and anionic sites (AS) of the glomerular basement membrane (GBM) was studied in puromycin aminonucleoside (PA) nephrotic rats. In addition the rats exogenously given human recombinant interleukin-2 (hrIL-2) every day repeated the same proteinuria were used. The PA nephrotic rats were made by single injection of PA 150 mg/kg excrete of urinary protein as compared 10 mg/day of urinary protein in the controls. The increase of urinary protein in the PA rats was inhibited by CYA10-20 mg/kg administrated orally from the day of PA injection for 15 days. To evaluate AS, the kidney were treated with a polyethyleneimine (PEI) staining method and the deposits in the lamina rara externa (LRE) of the GBM were counted on the electron micrographs. On the 15th day, in the PA rats, AS decreased greatly but were normal in the CYA-treated rats. On one hand, rats injected of hr IL-2 2.5 X 10(5)U/rat intraperitoneally for 14 days showed slight proteinuria on the 14th day, and the proteinuria was also inhibited by oral administration of CYA 25 mg/kg. As reduced in the rats treated with hrIL-2 as well as PA. The findings indicate that the proteinuria in the PA nephrotic rats and rats treated with hrIL-2 might result from reduction of AS and that the improvement of proteinuria in these rats by CYA might be due to the recovery of AS in the GBM.

Animals↗
PubMed1990

[The diagnostic value of cine-MR imaging in diseases of great vessels].

The diagnostic value of cine magnetic resonance imaging (cine-MRI) was evaluated in 10 patients with disease of great vessels. The parameters necessary to decide the appropriate treatment, such as presence and extension of intimal flap, DeBakey type classification, identification of the entry, differentiation between true and false lumen, and between thrombosis and slow flow were demonstrated in all patients with dissecting aortic aneurysm. However, abdominal aortic branches could not be demonstrated enough by cine-MRI, therefore conventional AOG was necessary to choose the operative procedure in these cases. In patients with thoracic aortic aneurysm (TAA), cine-MRI was valuable in demonstrating both blood flow and thrombus in the lumen of aneurysm, and AOG was thought to be unnecessary in most cases. Cine-MRI is a promising new technique for the evaluation of diseases of great vessels.

Aged↗
PubMed1990

Malignant Zollinger-Ellison syndrome. Stabilization of liver metastasis after gastrectomy with resection of primary tumor.

A case of malignant gastrinoma of the jejunum and jejunal mesentery, with findings of metastasis in the liver was studied. Tumor resection and remnant gastrectomy, as well as liver biopsy, were performed. Of all the tumors removed, the metastatic tumor had the lowest gastrin content, which was 1.5 times that found in normal human antral mucosa. The gastrin distribution was of four peaks and one peak for the main tumor, versus two peaks for the metastatic tumor in which G17 was the main component. Seven years after the operation, computed tomography (CT) scan indicated there was stabilization of the liver metastasis, and now, ten years after the total gastrectomy, the patient is well and working full-time. Such an analysis can be of value in determining the prognosis in cases of malignant gastrinoma with liver metastasis.

Adult↗
PubMed1990

[Late results with biograft in peripheral arterial surgery].

A total of 106 vascular reconstructions below the inguinal ligament including axillo-femoral and femoro-femoral bypasses were performed using 137 Dardik's human umbilical veins. The indication for surgery was limb salvage in 29%. The distal anastomosis was done with the popliteal artery above the knee in 53 cases, below the knee in 31, and with a tibial artery in 1. The axillo-femoral bypass was performed in 21 cases, and femoro-femoral bypass in 32. The accumulated graft patency rates of femoro-popliteal bypass at 1 yr./3 yrs./5 yrs. were 93%/75%/75%, those of femoro-femoral bypass were 85%/85%/85%, and those of axillo-femoral bypass were 54%/27%/27%. No special risk factor influencing patency rate was found from this study. In long term period, graft aneurysm was observed in 3 cases. It is concluded that the human umbilical vein is the graft material of choice for femoro-popliteal or femoro-femoral bypass when the saphenous vein is not available, and the careful follow-up is important because of the risk of graft aneurysm.

Adult↗
PubMed1989

Cloning of human gene encoding prostaglandin endoperoxide synthase and primary structure of the enzyme.

The complete amino acid sequence of human prostaglandin endoperoxide synthase (EC 1.14.99.1, cyclooxygenase) was deduced by cloning and sequence analysis of human genomic DNA coding for the enzyme. The isolated clones covered approximately 40 kilobase pairs of human gene and the protein coding region of the enzyme was distributed into eleven exons, which encoded 599 amino acid residues with a calculated molecular weight of 68,548. Human prostaglandin endoperoxide synthase exhibited 91% amino acid identity with the sheep enzyme.

Amino Acid Sequence↗
PubMed1989

Primary structure and functional expression from complementary DNA of the rod photoreceptor cyclic GMP-gated channel.

The complete amino-acid sequence of the cyclic GMP-gated channel from bovine retinal rod photoreceptors, deduced by cloning and sequencing its complementary DNA, shows that the protein contains several putative transmembrane segments, followed by a region that is similar to the cyclic GMP-binding domains of cyclic GMP-dependent protein kinase. Expression of the complementary DNA produces cyclic GMP-gated channel activity in Xenopus oocytes.

Amino Acid Sequence↗
PubMed1989

Cloning and characterization of cDNA for mitochondrial GTP:AMP phosphotransferase of bovine liver.

Three different types of cDNA clones for mitochondrial GTP:AMP phosphotransferase (AK3) were isolated from a cDNA library of bovine liver poly(A)+ RNA. Nucleotide sequencing revealed that each of these clones consisted of a common 5'-untranslated region, a common AK3-coding sequence and a 3'-untranslated region with different sizes. By Northern blot analysis, three species of AK3 mRNA apparently corresponding to the isolated cDNA clones were detected, which would be a result of varying terminations and polyadenylations of the primary transcript. From comparison of the size of the product synthesized in vitro from the message directed by the isolated cDNA with that of the purified AK3 protein, AK3 appeared to have no cleavable NH2-terminal sequence as found in other mitochondrial proteins. The AK3 cDNA was expressed in Escherichia coli, which resulted in complementation of an adenylate kinase mutation of E. coli. The AK3 product was exported to the periplasmic space through the bacterial inner membrane. The possible involvement of the NH2-terminal sequence of the protein in targeting to the mitochondrial matrix was discussed.

Amino Acid Sequence↗
PubMed1989

Cell-adhesive immunoglobulin M in human plasma.

Human plasma contains a cell-adhesive protein that has a structure related to immunoglobulins. This protein was purified by affinity chromatography on an elastin-Sepharose column and by Mono Q anion-exchange chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis under non-reducing and reducing conditions revealed that this protein is a kind of immunoglobulin M (IgM). Antibodies against the mu chain and against the Fc region of IgM inhibited the adhesion of cells to this protein. Addition of the peptide GRGDS into media inhibited the adhesion, too. These results suggest that this protein is a special subset of IgM having a cell-binding sequence in the Fc region. We propose the name "cell-adhesive immunoglobulin M (CA-IgM)" for this protein. CA-IgM binds to alpha-elastin and laminin suggesting that it may play a role in the interaction between cells and the extracellular matrix.

Animals↗
PubMed1989

Primary structure and functional expression of the cardiac dihydropyridine-sensitive calcium channel.

In cardiac muscle, where Ca2+ influx across the sarcolemma is essential for contraction, the dihydropyridine (DHP)-sensitive L-type calcium channel represents the major entry pathway of extracellular Ca2+. We have previously elucidated the primary structure of the rabbit skeletal muscle DHP receptor by cloning and sequencing the complementary DNA. An expression plasmid carrying this cDNA, microinjected into cultured skeletal muscle cells from mice with muscular dysgenesis, has been shown to restore both excitation-contraction coupling and slow calcium current missing from these cells, so that a dual role for the DHP receptor in skeletal muscle transverse tubules is suggested. We report here the complete amino-acid sequence of the rabbit cardiac DHP receptor, deduced from the cDNA sequence. We also show that messenger RNA derived from the cardiac DHP receptor cDNA is sufficient to direct the formation of a functional DHP-sensitive calcium channel in Xenopus oocytes. Furthermore, higher calcium-channel activity is observed when mRNA specific for the polypeptide of relative molecular mass approximately 140,000 (alpha 2-subunit) associated with skeletal muscle DHP receptor is co-injected.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1989

Continued high albumin production by multicellular spheroids of adult rat hepatocytes formed in the presence of liver-derived proteoglycans.

Adult rat hepatocytes formed floating multicellular spheroids, when they were cultured with proteoglycan fraction isolated from rat liver reticulin fibers. Cells in the spheroid showed only low growth activity. Albumin production by the spheroids increased up to 1.5 micrograms/micrograms DNA/day (180 micrograms/mg Protein/day) during the first 6 days and remained constant thereafter. In contrast, the albumin production by the monolayer markedly decreased after 4 days. The spheroid culture appears to be more suitable than the monolayer in studying differentiated functions of adult hepatocytes.

Albumins↗
PubMed1989

Immunohistochemical study on fetal raphe samples transplanted into the leptomeningeal tissue of 5,6-dihydroxytryptamine-treated adult rats.

Pieces of fetal midbrain raphe containing serotonergic and dopaminergic neurons were transplanted into the leptomeningeal tissue of adult host rats that had previously been denervated by treatment with 5,6-dihydroxytryptamine. One, 2 and 5 months after transplantation, the rate of neuronal survival in the grafted tissue and the extent of axonal outgrowth into the host brain were studied by use of serotonin and tyrosine hydroxylase (TH) immunohistochemistry. The survival rate of the grafts in the 1-month group was approximately 70%. Neurons containing either serotonin or catecholamine were demonstrated by means of immunocytochemical procedures in the grafts. Two and 5 months after transplantation, serotonin-immunoreactive nerve fibers were densely distributed throughout the graft tissue, while TH-immunoreactive fiber elements were restricted to an area near the somata of TH-positive neurons. Numerous serotonin-immunoreactive fibers derived from the transplant were found in the leptomeningeal tissue surrounding the graft, on the wall of neighboring blood vessels, and also in the adjacent parenchyma of the host brain. Outgrowing TH-immunoreactive nerve fibers were not observed in the host brain, although such elements occurred in the leptomeningeal tissue and the wall of the larger blood vessels. These results suggest that the serotonergic and catecholaminergic (dopaminergic) neurons located in transplants of the raphe nuclei show different patterns when reinnervating the host tissue.

5,6-Dihydroxytryptamine↗