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Biomedical subjects

K Hotta

Publications and source records attributed to K Hotta.

At least 181 records · Page 10Linked to original sources
PubMed1994

[A surgical treatment of ruptured arch aneurysm].

A 83-year-old woman was admitted to our hospital because of back pain and shock. Her chest X-ray and CT scan demonstrated a large arch aneurysm and hemothorax, suggesting ruptured aortic arch aneurysm. The ruptured aortic arch aneurysm was replaced with a woven Dacron graft under selective cerebral perfusion (SCP). Her postoperative course was uneventful without any neurological deficits. For the past three years, we have utilized SCP in 12 cases of arch aneurysms. There were three early deaths in this series. The cause of death were bleeding in one patient and cerebral accident in two patients. The latter two patients had severe atheromatous changes in the aortic wall. The SCP technique was a useful method of cerebral protection, especially for elderly patient with aortic arch aneurysm.

Aged↗
PubMed1993

Stimulation of mucus glycoprotein biosynthesis in rat gastric mucosa by gastrin.

We examined the effects of the gastrin family of peptides on gastric mucus glycoprotein (mucin) biosynthesis in rat gastric mucosa using an organ culture technique. Radiolabeled mucin was obtained from the tissue and culture medium of the corpus and antrum of rat stomach incubated for 5 hr with [3H]glucosamine (GlcN), [14C]threonine (Thr), and [35S]sulfate in vitro. With the addition of 10(-8) and 10(-7) M tetragastrin to the culture medium, [3H]GlcN labeled mucin in the corpus tissue increased to 120-135% that of the control (P < 0.01). The biosynthetic responses to cholecystokinin (CCK)-8 and the 17-peptide gastrin were essentially the same as that to tetragastrin. Tetragastrin 10(-8) M also increased the incorporation of [35S]sulfate into the corpus mucin but failed to change [14C]Thr incorporation. In the antrum, biosynthetic activity showed no significant change with 10(-9) approximately 10(-5) M tetragastrin. Ranitidine, diphenhydramine and omeprazole at 10(-5) M did not suppress the tetragastrin-induced increase in [3H]GlcN incorporation into mucin, but L-365,260 at a concentration of 10(-6) M completely blocked this effect. These results suggest that gastrin stimulates mucin production via CCK-B/gastrin receptors in the oxyntic region of rat gastric mucosa.

Animals↗
PubMed1993

Cloning of a canine gene homologous to the human interleukin-8-encoding gene.

We cloned a 2.3-kb sequence homologous to the gene (hIL8) encoding human interleukin-8 (hIL-8) from the canine genome. The sequence may encode an 11.3-kDa protein consisting of 101 amino acids, sharing 75, 80 or 85% identity with the human, rabbit or porcine IL-8 proteins, respectively. Southern and Northern blot analyses indicated that the cloned sequence appeared to exist as a single copy in the canine genome, and that its expression was inducible with lipopolysaccharide in canine mononuclear cells, respectively. Thus, it seems very likely that the cloned gene is a canine homologue of hIL8.

Amino Acid Sequence↗
PubMed1993

Regional differences in sulfated oligosaccharides of rat gastrointestinal mucin as detected by two-dimensional chromatography.

Radiolabeled sulfated mucin was obtained from rat gastrointestinal tract tissue (corpus, antrum, duodenum, jejunum, ileum, or colon) incubated with [35S]sulfate in vitro by fractionation of extracts on Superose 6 followed by purification with CsCl density gradient centrifugation. Significant amounts of 35S-labeled mucin were obtained from each tissue and radioactivity differed according to region, in the order colon > duodenum > jejunum > corpus > antrum > ileum. Gel-permeation chromatography of 35S-labeled oligosaccharides liberated from each mucin by alkaline-borohydrate treatment indicated the 35S-labeled oligosaccharides of each mucin differ with respect to elution position. Further examination of fractions eluted from the gel-permeation column by thin-layer chromatography showed region-specific chromatograms for the sulfated oligosaccharides. Thus, not only the degree of sulfate incorporation but sulfated oligosaccharide structure differs according to the region in gastrointestinal mucin.

Animals↗
PubMed1993

Comparative study on rat enteromucins.

1. Mucus glycoproteins (mucins) were extracted from the duodenum, small intestine (proximal and distal parts) and colon. 2. Enteromucin subunits were larger than 2 x 10(6). 3. The glycopeptides of enteromucins were essentially the same in size of the subunit. 4. The carbohydrate portion of enteromucins consisted of N-acetylgalactosamine, N-acetylglucosamine, galactose, fucose and sialic acid and the ratios of these sugars differed according to the region. 5. Average oligosaccharide length was about 8, 8, 8 and 14 sugars in the duodenum, proximal small intestine, distal small intestine and colon, respectively. 6. The proportion of threonine to serine in small intestinal mucins differed from duodenal and colonic mucins. Duodenal and colonic mucins were richer in threonine than small intestinal mucins. 7. Proximal and distal small intestinal mucins showed the same features. 8. A comparison of rat enteromucins to gastromucins indicated enteromucins to have large subunits and glycopeptides. The threonine and sialic acid content of enteromucins was higher and fucose content less compared to gastromucins.

Acetylgalactosamine↗
PubMed1993

Regional differences in pig gastric mucins.

1. Mucus glycoproteins (mucins) were extracted from cardiac, fundic and pyloric regions of pig stomach. 2. The cardiac and pyloric regions were richer with mucins than the fundic region. 3. Threonine and proline content decreased in the order of cardiac, fundic and pyloric mucin. That of serine increased in the order of cardiac, fundic and pyloric mucins. 4. The carbohydrate of gastric mucins consisted of N-acetylgalactosamine, N-acetylglucosamine, galactose and fucose. The ratios of carbohydrate composition among cardiac, fundic and pyloric mucins differed. 5. Average oligosaccharide length was about 14-15, 12-13 and nine sugars in cardiac, fundic and pyloric mucins, respectively. 6. Disulfide bond reduction of mucins with dithiothreitol led to the production of a larger (M(r) about 8.8 x 10(7)) and a smaller subunit (M(r) about 1.2 x 10(6)). Their ratio differed for each of the three regions. The proportion of the larger subunit decreased in the order of cardiac, fundic and pyloric mucins, as 100, 61.4 and 44.8%, respectively.

Acetylgalactosamine↗
PubMed1993

Development of an HPLC method to estimate hexosamines and its application to determine mucin content in rat and human gastric mucosa.

1. An HPLC analysis of hexosamines and related compounds modified from the Waters Pico-Tag amino acid analysis procedure is described. 2. This method is applicable to determine glucosamine and galactosamine not only in the hydrolyzate of purified glycoconjugate such as gastric mucin and ovalbumin but also in crude materials such as rat gastric mucosal extract and powdered bovine nasal cartilage. 3. Compared with a conventional colorimetric hexosamine determination, sensitivity of this method is almost 100 times higher. 4. By applying this method, a simple but highly sensitive procedure to determine mucin content in a crude stomach specimen of rat and that in a biopsied human gastric mucosa was also developed.

Adult↗
PubMed1993

Comparison of the mucus glycoproteins present in the different layers of rat gastric mucosa.

1. Applying a newly developed separation method, mucus glycoproteins (mucins) present in the different layers of gastric mucosa in rats were studied. 2. Distributions of mucin in the four layers of gastric mucosa expressed as mg mucin hexose per animal are: deep mucosa of corpus, 705; deep mucosa of antrum, 163; surface mucus, 421; mucus gel, 30; and soluble mucus, 173. 3. Relatively low molecular sugar chains, having a small amount of neutral sugars, are rich in the deep corpus and deep antral mucin. 4. Higher molecular size carbohydrate chains, rich in fucose and galactose, are abundant in the surface mucus and mucus gel-derived mucin.

Amino Acids↗
PubMed1993

A monoclonal antibody against carbohydrate moiety of rat gastric surface epithelial cell-derived mucin.

A monoclonal antibody (MAb), designated RGM11, was generated against mucin purified from the surface epithelial layer of rat gastric mucosa. RGM11 reacted with the purified mucin which had been attached to the ELISA well. This reaction was inhibited by the oxidation of the ELISA well with periodate, indicating the carbohydrate moiety of the mucin molecule to be the epitope of RGM11. Treatment of the ELISA well with galactose oxidase also reduced the reaction with this MAb, thus suggesting the peripheral galactose and/or N-acetylgalactosamine residues of the carbohydrate moiety of mucin are involved in the epitope structure. Histochemical observation indicated that this MAb was able to stain the formalin fixed-paraffin embedded sections of rat and was positive to the surface mucous cells of corpus and antral region of the stomach and the villus epithelium of the duodenal mucosa, but other organs and tissues of rat so far examined were all negative to this MAb. These results indicate that this newly established MAb, labelled RGM11, might be useful to estimate the physiological changes in gastric surface mucous cells and the role of surface epithelial cell derived mucus in the gastric mucosal defense mechanisms.

Animals↗
PubMed1993

Effects of the muscarinic receptor agonist carbachol and/or antagonist pirenzepine on gastric mucus secretion in rats.

The effects of the muscarinic agonist carbachol on the secretion and accumulation of gastric mucus glycoprotein (mucin) were examined. Gastric mucin obtained from the soluble mucus, adherent mucus gel, and surface mucosal and deep mucosal layer was isolated and quantified. One hour after the subcutaneous administration of carbachol (0.08-80 micrograms/kg body weight) the deep corpus mucin content had decreased significantly (75% of control), corresponding to an increase (120% of control) in the soluble mucin content with 0.8 microgram/kg of carbachol treatment. These changes were counteracted by 10 mg/kg of pirenzepine (selective M1 antagonist) pretreatment. On a single administration of 10 mg/kg of pirenzepine, deep corpus mucin tended to increase, and soluble mucin decreased significantly (49% of the control). These two drugs failed to cause any significant change in the mucin content of the surface and antral deep mucosa or the adherent mucus gel. The muscarinic agonist and the M1 antagonist are thus shown to accelerate the secretion and accumulation, respectively, of mucin in the deep corpus mucosa. Thus intrinsic M1 receptor may possibly be involved in the secretion of mucin in the gastric deep corpus mucosa.

Animals↗
PubMed1992

Partial purification and characterization of an endo-alpha-N-acetylgalactosaminidase from the culture medium of Streptomyces sp. OH-11242.

For the purification of a new type of endo-alpha-N-acetylgalactosaminidase from the culture medium of Streptomyces sp. OH-11242 (endo-GalNAc-ase-S) [Iwase, Ishii, Ishihara, Tanaka, Omura & Hotta (1988) Biochem. Biophys. Res. Commun. 151, 422-428], a method for assaying enzyme activity was established. Using purified pig gastric mucus glycoprotein (PGM) as the substrate, oligosaccharides liberated from PGM were pyridylaminated, and the reducing terminal sugars of oligosaccharides larger than Gal beta 1-3GalNAc were analysed by h.p.1.c. The crude enzyme of endo-GalNAc-ase-S was prepared as an 80% (w/v) ammonium sulphate precipitate from the concentrated culture medium. The enzyme was partially purified by gel chromatofocusing and subsequent DEAE-Toyopearl chromatography. Endo-enzyme activity eluted around pI 4.8 on a gel chromatofocusing column and eluted with 0.19-0.25 M-NaCl on a DEAE-Toyopearl column. In the enzyme fraction obtained, no exo-glycosidases or proteases could be detected. The molecular mass of the enzyme was estimated as 105 kDa by gel filtration, and the optimum pH was 5.5. Endo-GalNAc-ase-S hydrolysed the O-glycosidic linkage between GalNAc and Ser (Thr) in 3H-labelled and unlabelled asialofetuin, liberating both the disaccharide (Gal beta 1-3GalNAc) and the tetrasaccharide [Gal beta 1-3 (Gal beta 1-4GlcNAc beta 1-6)GalNAc]. When endo-alpha-N-acetylgalactosaminidase from Alcaligenes sp. (endo-GalNac-ase-A) was incubated with 3H-labelled and unlabelled asialofetuin, only the disaccharide (Gal beta 1-3GalNAc) was liberated.

Asialoglycoproteins↗
PubMed1992

Secondary aminoglycoside resistance in aminoglycoside-producing strains of Streptomyces.

The role of aminoglycoside (AG) acetyltransferases (AACs) and of the corresponding genes in resistance to foreign AGs in AG-producing strains of Streptomyces were studied. The research focussed on (i) the activation mechanism of the cryptic kanamycin(Km)-resistance-encoding gene that encodes an AAC(3) in streptomycin-producing S. griseus SS-1198, and (ii) an AAC(2') with novel activity and substrate specificity in kasugamycin-producing S. kasugaensis MB273. Activation of the cryptic kan gene in S. griseus SS-1198 is probably due to a single base substitution at the putative -10 promoter region, leading to the enhancement of transcription, resulting in resistance to AG. The coding region of the kan gene was highly homologous to that of the aacC7 gene of paromomycin-producing S. rimosus forma paromomycinus. On the other hand, resistance in S. kasugaensis MB273 was found to be due to an AAC(2') capable of acetylating astromicin group AGs at two different sites (1-NH2 with istamycin B, and 2'-NH2 with astromicin and istamycin A). These additional antibiotic resistances that are independent of a self-resistance basis may be regarded as 'secondary' resistances, so as to distinguish them from 'primary' resistances arising from a self-resistance basis.

Aminoglycosides↗
PubMed1992

Change of membrane potential in rat urinary bladder epithelium treated with sodium L-ascorbate.

We previously showed that 5% sodium L-ascorbate (Na-AsA) in the diet promotes rat urinary bladder carcinogenesis, whereas 5% ascorbic acid (AsA) and 1% sodium chloride (NaCl) in the diet do not. In order to cast light on basic properties of these compounds regarding the rat urinary bladder, we examined membrane potential levels in the bladder epithelium of F344 rats treated with 5% Na-AsA, 5% AsA or 1% NaCl in the diet for 2, 4 or 8 weeks. Microelectrode measurement showed Na-AsA to induce hyperpolarization of the membrane potential, which was, however, lacking with AsA and NaCl from week 2 until the end of experiment. Thus a good correlation between the effects on membrane potential and tumor promoting activity could be established.

Animals↗
PubMed1992

Effects of tetragastrin on mucus glycoprotein in rat gastric mucosal protection.

The effects of tetragastrin on mucus glycoprotein (mucin) metabolism and mucosal protection in rat gastric mucosa were investigated. Rats were administered with various doses of tetragastrin (12, 120, or 400 micrograms/kg body weight; s.c.), followed by 50% ethanol-induced gastric injury. Tetragastrin caused a significant increase in mucin content in the corpus mucosa and prevented 50% ethanol-induced gastric mucosal damage in a dose-dependent manner. For assessment of the effects of tetragastrin on the metabolism of gastric mucin in detail, changes in mucin distribution in the three different layers of rat gastric mucosa were examined one hour after single administration of tetragastrin. A significant increase in the mucin content was noted in the mucus gel and surface mucosal layer. Mucin content in the deep mucosa corresponding mainly to the mucus neck cell mucin underwent virtually no change by this treatment. An increase in mucin in the mucus gel and surface mucosa would thus appear due to the administration of tetragastrin and may possibly be related to the protective action of the gastric mucosa against injury. The data demonstrate a possibility that gastrin may have potential for enhancing gastric mucosal protection associated with mucus secretion and/or mucus synthesis on the surface mucosa of rat gastric mucosa.

Animals↗