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Biomedical subjects

M Oda

Publications and source records attributed to M Oda.

At least 451 records · Page 25Linked to original sources
PubMed1988

Alterations in gastric mucosal microvascular endothelium in a stressed condition--relevance to gastric ulcerogenesis.

The present paper describes the morphological and functional alterations of the gastric mucosal microvascular endothelium under restraint-stressed condition. On the basis of the direct cholinergic innervation of capillaries and non-muscular venules in the gastric mucosa, these endothelial changes would be caused by the stress-induced overstimulation of the cholinergic nerves and modified by the degranulation of mast cells, contributing to the stress-induced ulcer formation as schematically illustrated in Fig. 10.

Aged↗
PubMed1988

Interactions between cations in modifying the binding of hexokinases I and II to mitochondria.

Interactions between cations in modifying the binding of hexokinases I and II to mitochondria was examined with reference to the intracellular condition. Mitochondria-binding of either of hexokinases I and II, both prepared from mouse ascites ELD cells, was markedly increased by Mg2+ as has been known well. However, even in the absence of Mg2+, marked binding was attained by 100 mM K+ alone especially for hexokinase I, which seemed generally more ready to bind to mitochondria. On the other hand, the effect of Mg2+ to increase the binding was reduced by the addition of K+, and the decreasing effect of K+ was much more marked for hexokinase II than I. These results indicate that, in addition to Mg2+, monovalent cations as represented by K+, also have marked effect on the binding, and the effect is different for each hexokinases I and II, which may be responsible for the difference in the intracellular distribution between these hexokinases.

Animals↗
PubMed1988

Autoradiographic demonstration of gastrin-releasing peptide-binding sites in the rat gastric mucosa.

The location of [125I]iodotyrosyl gastrin-releasing peptide-binding sites in the rat fundic mucosa was studied. Peptide specificity was demonstrated by competitive binding studies using the addition of a large amount of cold gastrin-releasing peptide or substance P. Autoradiography of the stomach tissue was carried out by freeze-drying, embedding in Epon, wet-sectioning with ethylene glycol, and dry-mounting the emulsion film by the wire-loop method to prevent loss of the labeled substance. Specific binding sites of gastrin-releasing peptide were found on D cells, surface mucus cells, and parietal cells, whereas few binding sites were seen on the chief or mucus neck cells.

Animals↗
PubMed1988

Endogenous platelet-activating factor and anti-platelet-activating factor in patients with renovascular hypertension.

Renovascular hypertension is relieved by percutaneous transluminal renal angioplasty. In four patients with renovascular hypertension, platelet-activating factor (PAF) was found to be released into the ipsilateral renal venous blood after percutaneous transluminal renal angioplasty, but was not found in the contralateral renal venous blood following this procedure. Anti-platelet-activating factor with a lipid-like property was also found, and its polarity was slightly lower than that of PAF judging by its behavior on thin layer chromatography. Anti-platelet-activating factor completely blocked the aggregation of rabbit platelets induced by PAF, ADP or arachidonic acid. These results indicate that PAF and anti-platelet-activating factor are released into renal venous blood following percutaneous transluminal renal angioplasty in patients with renovascular hypertension.

Adenosine Diphosphate↗
PubMed1988

Involvement of autonomic nervous system in gastric mucosal defense mechanism.

This article describes the histochemical, immunohistochemical, radioautographic, and ultrastructural localizations of aminergic and peptidergic nerves, neurotransmitter receptors, and their binding sites in the stomach wall. Cholinergic and vasoactive intestinal polypeptide (VIP)-ergic nerve fibers are distributed along the gastric microvasculature, within the myenteric and submucosal plexuses, and in the muscularis mucosae and circular muscle layer. In the mucosa, both nerve fibers evenly extend along the capillaries in association with the epithelial cells up to the mucosal surface. In particular, cholinergic nerves are proved to doubly innervate the mucosal capillaries and nonmuscular venules as well as the parietal cells. Adrenergic and neuropeptide Y (NPY)-containing nerves are distributed primarily along the arterioles of the gastric microvasculature, within the myenteric plexuses, and in the circular muscle layer. These nerve fibers extend up to the basal portion of the mucosa in close association with small arterioles, capillaries, and epithelial cells. Some of the adrenergic nerve axons are coexistent with the cholinergic nerve axons within the Schwann cell. Histamine H1 receptors are widely located on the walls of arterioles, capillaries and venules, while H2 receptors are evident not only on the parietal cells but also on the walls of the collecting venules and surrounding capillaries in the mucosa. Dopamine D1 receptors are predominantly located on the smooth muscle cells of the arterioles near the muscularis mucosae, while D2 receptors are present on the walls of postcapillary venules and collecting venules. Functional coordination of both intramural peptidergic nerves as intrinsic origin and aminergic nerves as extrinsic origin is considered to be essential for maintaining the gastric mucosal defense mechanism against a variety of aggressive factors.

Animals↗
PubMed1988

Serological variation in oral Streptococcus milleri.

Serological variation in 71 oral isolates and three reference strains of Streptococcus milleri was examined. Antisera were raised by immunising rabbits with cells of 10 selected strains, followed by absorption of non-specific antibodies. Double diffusion of the typing sera and the Rantz and Randall extracts of the strains in agar gel demonstrated that 70 strains were divided into 10 serotypes (a-j) on the basis of cell-surface carbohydrate antigens. Only four strains were untypable. The typing scheme proposed depends on type antigens other than the Lancefield group antigens A, C, F, G and others, although strains belonging to the serotypes a, c and f strictly corresponded to those of the groups A, C and F respectively. Close correlation between the present serotyping scheme and the previously proposed biotyping scheme for S. milleri was demonstrated. Distribution of these strains in dental plaque obtained from young adults was also investigated.

Animals↗
PubMed1988

Cloning and nucleotide sequences of histidase and regulatory genes in the Bacillus subtilis hut operon and positive regulation of the operon.

An 8-kilobase HindIII fragment carrying the histidase gene (hutH) and its regulatory region (hutP), from the Bacillus subtilis histidine utilization (hut) operon, was cloned in the temperate bacteriophage phi 105. Histidine utilization was restored in a hutH1 mutant by the specialized transducing phage (phi 105hutH11). The histidase gene in phi 105hutH11 was inducible and was shown to be under catabolite repression. The nucleotide sequence of 3,932 base pairs including the hutH and hutP loci revealed three open reading frames (ORFs). The molecular weights of ORF1 and ORF2 proteins were calculated to be 16,576 (151 amino acid residues) and 55,675 (508 amino acid residues), respectively. Reverse transcriptase mapping experiments showed that the putative promoter for the hut operon could be recognized by RNA polymerase sigma 43. The transcript starts at an adenosine residue 32 base pairs upstream from the initiation codon of ORF1. hutH+-transforming activity was found in ORF2, indicating that ORF2 encoded the histidase. A hutP1 mutation was determined as a substitution of an amino acid in ORF1. By using a specialized transducing phage containing the wild-type ORF1 gene, it was demonstrated that the presence of ORF1 protein in trans was absolutely required for the induction of the hut operon in a hutP1 mutant. These data strongly suggested that ORF1 encodes a positive regulator of the hut operon.

Amino Acid Sequence↗
PubMed1988

Anaphylactoid reaction to oxytocin during cesarean section.

A case of an allergic reaction to synthetic oxytocin administered during cesarean section is reported. Epinephrine was more effective in improving the severe hypotension than ephedrine. The incidence of anaphylactoid reaction to oxytocin is very low, but this potential problem must always be kept in mind in daily obstetric practice.

Adult↗
PubMed1988

Microcirculatory disturbances in endotoxin-induced disseminated intravascular coagulation. The effects of heparin and gabexate mesilate on locomotive and metabolic changes of neutrophils.

Neutrophil-mediated oxidative stress on the rat mesenteric microcirculation was studied in the experimental model of endotoxin-induced disseminated intravascular coagulation (DIC) by using an intravital fluorescent technique and luminol-dependent chemiluminescence (ChL) analysis. Leukocytes sticking to the venules were visualized by the injection of acridine orange, a fluorochrome tracer which shows high affinity to white cells. Endotoxin (E coli, O-111B4, Difco, USA) was infused intravenously at a dose of 2 mg/kg/hr. After starting the infusion of endotoxin, the number of sticking cells were gradually increased on the venular endothelium followed by a transient neutropenia. In order to investigate the distribution of infused endotoxin in the microvasculature, FITC-labeled endotoxin (Sigma, USA) was used. After administration of FITC-endotoxin, multiple patches of fluorescence along the venular walls were observed, while no fluorescent conjugates were found at the sticking neutrophils and along the arteriolar walls. ChL activities of neutrophils were also dramatically elevated, which may reflect the enhanced ability to generate oxyradical species. To investigate the inhibitory effects of heparin sodium and gabexate mesilate which was a synthetic protease inhibitor on locomotive and metabolic changes of neutrophils induced by endotoxemia, both agents were administered prior to endotoxin infusion. Gabexate mesilate attenuated these changes, but heparin sodium did not show any improving effects. It was concluded that endotoxin primarily affects the venular endothelial cells, resulting in the activation of neutrophils. Gabexate mesilate was more likely to attenuate neutrophil-mediated oxidative stress on microvasculature in endotoxin-induced DIC than heparin sodium.

Animals↗
PubMed1988

[A case of a probable "cancer family syndrome" presenting four synchronous malignancies of the colon].

A 72-year-old male was admitted because of right lower quadrant pain, Barium enema and total colonoscopy disclosed multiple colon cancers and sequentially, a subtotal colectomy was performed. The resected specimen demonstrated 3 advanced carcinomas and an adenomatous cancer with additional multiple polyps. Investigation of his family history revealed that his mother and his elder sister had died of uterine cancer, and that his elder brother, his nephew, and his niece had been operated on for colorectal cancer. We thus supposed a case of "Cancer Family Syndrome" presenting multiple neoplasms of the colon.

Adenocarcinoma↗