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T Azuma

Publications and source records attributed to T Azuma.

At least 127 records · Page 7Linked to original sources
PubMed1986

Pre- and postjunctional alpha-adrenoceptors at sympathetic neuroeffector junction in bovine mesenteric lymphatics.

We studied isolated bovine mesenteric lymphatics to elucidate the pharmacological characteristics of pre- and postjunctional alpha-adrenoceptors at the sympathetic neuroeffector junction. Cylindrical strips were incubated with [3H]-noradrenaline and mounted for superfusion. Electrical stimulation (2 Hz, 0.5 msec, 50 V) augmented the fractional release of labeled noradrenaline. Exogenous noradrenaline and clonidine caused a depression of the evoked tracer release. Phenoxybenzamine and yohimbine markedly enhanced the evoked overflow of adrenergic transmitter. Rings of lymphatic vessels were mounted for isometric tension recording in organ chambers filled with Krebs-Ringer bicarbonate solution. The vessels contracted when exposed to phenylephrine and clonidine. The ED50 of clonidine was significantly lower than that of phenylephrine. Prazosin caused a parallel shift to the right of the dose-response curve to phenylephrine. The antagonist, however, suppressed the magnitude of the maximum response to clonidine. Yohimbine caused parallel shift to the right of the dose-response curves to phenylephrine and clonidine, respectively. The Schild plots for yohimbine demonstrated that the drug was a competitive antagonist to phenylephrine and clonidine. The pA2 value of yohimbine to clonidine (7.6 +/- 0.4) was larger than that to phenylephrine (6.2 +/- 0.4). The pA2 value of prazosin to phenylephrine was 7.2 +/- 0.3. These results suggest that prejunctional alpha-adrenoceptors are involved in the negative feedback mechanism for autoregulation of noradrenaline release during postganglionic sympathetic nerve stimulation, and that both alpha 1- and alpha 2-like adrenoceptors do exist on lymphatic smooth muscle cells.

Adrenergic Fibers↗
PubMed1986

Fine specificity analysis of idiotype-specific suppressor factors that block a delayed-type hypersensitivity response to M315: evidence supporting a role for somatic mutations in the variable region of the lambda 2 chain of M315.

The delayed-type hypersensitivity (DTH) response in BALB/c mice to the idiotype of M315 (alpha,lambda 2), a BALB/c myeloma protein, can be suppressed by a single i.v. injection of soluble M315. This suppression involves the generation of suppressor T cells. Mice tolerized by M315 produce subcellular factors that suppress the M315-DTH response. Such suppressor factors can be obtained by mechanical disruption of spleen cells or thymocytes from mice treated i.v. with M315. The fine specificity of the factor was studied using various immunoadsorbents such as L315 and germline V lambda 2 chain-Sepharose beads with known amino acid sequences. The results indicated that the specificity of the factor depended on three contiguous somatically mutated amino acid residues, Phe94, Arg95 and Asn96, in the third hypervariable region of the V domain of the L chain of M315.

Animals↗
PubMed1986

Schwannoma of the trachea.

We recently encountered a tracheal schwannoma presenting as a polypoid mass. Computed tomography (CT) was very effective in evaluation of the size, shape and site of this rare tumour. Furthermore, CT images in the prone position made it easy to exclude tumour extension into the mediastinum.

Humans↗
PubMed1985

Active site of intestinal gamma-glutamyltransferase faces luminal side of brush border membrane.

Purified gamma-glutamyltransferase from hog small intestine was competitively inhibited by glutathione in vitro when L-gamma-glutamyl-p-nitroanilide was used as a substrate. An S-acetyldextran derivative of glutathione inhibited the enzyme as well as glutathione, although dextran had no inhibitory effect. gamma-Glutamyltransferase in the rat small intestine could utilize in situ L-gamma-glutamyl-p-nitroanilide circulated in the lumen, and was inhibited by the impermeable derivative of glutathione which was on the luminal side. These data suggested that the active site of intestinal gamma-glutamyltransferase faced the luminal side of the brush border membrane.

Aniline Compounds↗
PubMed1985

Somatic mutations in the variable region of the lambda 2 chain of M315 suppression of antibodies to the idiotype of M315.

BALB/c mice immunized with purified BALB/c myeloma protein M315 (alpha, lambda 2) produce anti-idiotypic antibody directed predominantly to a combinational (VH-315 + VL-315) determinant(s) of the M315 paratope (Sirisinha and Eisen, 1971; Tungkanak and Sirisinha, 1976). We examined whether the unique B cell response is influenced by pretreatment of mice with fragments or chains derived from M315 before immunization with M315. Intravenous (i.v.) injection of the Fv-315 fragment (VH-315 + VL-315) into normal BALB/c mice seven days before immunization with M315 resulted in marked suppression of anti-M315 idiotype antibodies. Studies on the structural requirement for suppression indicated that VL-315, but not VH-315, is involved. Structural comparison with a defined lambda 2 light (L) chain suggested that three contiguous amino acid residues in the third hypervariable loop of the variable (V) domain of the L chain of M315 are important for down-regulation of production of antibodies to the M315 idiotype.

Animals↗
PubMed1985

[Diagnostic value of angiography in differentiating the degree of the depressed type of gastric cancer].

Endoscopy and superselective angiography has been performed in 68 preoperative patients with the depressed type gastric cancer. The results are summarized as follows. Differentiation of the cancers into the early and the advanced was correct in 91%, and classification of the cancers into 3 groups (1 ; m, 2 ; sm, 3 ; advanced) was correct in 72% by endoscopy. Differentiation of the cancers into the early and the advanced was correct in 90%, and classification of the cancers into 4 groups (1 ; m X sm, 2 ; pm, 3 ; ss X se, 4 ; sei) was correct in 81% by the angiography. The rate of misdiagnosis, taking the early simulating advanced gastric cancer as the early, was 20% by the endoscopy, as compared to 8% by the angiography. Classification of the early simulating advanced gastric cancers into 3 groups (1 ; pm, 2 ; ss X se, 3 ; sei) was correct in 68% by the angiography. Excavated type cancer was likely to be overestimated as to the depth of invasion by the angiography. Poorly differentiated type, scirrhous type, and infiltrative growth with an ill defined border were found difficult to be correctly evaluated by both endoscopy and angiography. Preoperative angiography was useful for appropriate surgical therapy of the gastric cancer.

Adenocarcinoma↗
PubMed1985

[Preparation of the acetabulum to correct severe acetabular deficiency for total hip replacement--with special reference to stress distribution of the periacetabular region after operation].

The author analysed the radiological results of eighty-three total hip replacements in the patients with severely defective acetabulum secondary to congenital hip dysplasias or failed total hip replacements, after an average follow-up period of three years, paying particular attention to socket loosening. The patients with congenital hip dysplasias were divided into the following four groups: Group 1: The sockets were placed above the level of true acetabulum. Group 2: The sockets were placed in the true acetabulum with the cement used as a filler superolaterally. Group 3: The sockets were placed in the true acetabulum with bone grafts. Group 4: Eccentric sockets were placed in the true acetabulum. The incidence of radiological loosening of the socket was 50% in the group 1, 13% in the group 2, 6% in the group 3 and 75% in the group 4. The patients who underwent revision for socket loosening were also divided into two groups, the one whose acetabula were reconstructed with bone grafts and the other without bone graft. The incidence of radiological loosening of the socket was 28% in the group with bone grafts and 72% in the group without bone graft. The major factor that may have been responsible for socket loosening in these cases was considered to be poor mechanical condition around the socket due to bone deficiency. Two-dimensional finite element analysis was performed to establish the stresses in the periacetabular region after total hip replacement for acetabular deficiency. Model variations include, the conventional plastic socket of 44 mm outside, 28 mm inside diameter placed in false acetabulum or in high level, (2) in true acetabulum using bone cement as a filler, (3) in true acetabulum with bone graft and (4) eccentric socket placed in true acetabulum without bone graft. The ratio of von Mises stress to yield stress of each element were calculated. The results demonstrated that in the periacetabular region, the area superomedial to the socket was at high risk in each model. The area in periacetabular bone where the ratio of von Mises stress to yield stress was more than 20% was almost the same in model (1), (2), (4) and about a half of them in model (3). In conclusion, the most effective method to prevent the socket loosening after total hip replacement in the patient with deficient acetabulum was considered to reconstruct the new spherical acetabulum at anatomical position with bone graft.

Acetabulum↗
PubMed1984

Serotonin immunohistochemistry reveals immature EC cells.

Radioautographic studies of rat duodenal mucosa were carried out after single injections of 3H-thymidine, and the labelling indices of enterochromaffin (EC) cells identified by serotonin immunohistochemistry and by the diazo reaction were compared. The labelling index of EC cells by serotonin immunohistochemistry was 2.3% (mean percentage of 2 rats), while no labelled cells were found in diazo-positive EC cells. This finding indicates that serotonin immunohistochemistry reveals a less mature population of EC cells than conventional techniques such as the diazo reaction.

Animals↗
PubMed1984

Central intravascular papillary endothelial hyperplasia of the mandible.

Light and electron microscopic findings in papillary endothelial hyperplasia of the mandible in a 49-year-old female are reported. The endothelial cell-lined papillary projection into a cystic lumen was examined by light microscopy and characteristic features of the endothelial cells were found by electron microscopy. Factor VIII-related antigen was demonstrated in the endothelial cells by the immunoperoxidase technique.

Antigens↗
PubMed1984

Variegated effects of prostaglandins on spontaneous activity in bovine mesenteric lymphatics.

The effects of PGs (PGA2, PGB2, PGE2, PGF2 alpha, PGI2, and 6-keto PGF1 alpha) were investigated quantitatively in insolated bovine mesenteric lymphatics for elucidating the possible significance of PGs in lymph propulsion. 10(-8) M PGF2 alpha, PGA2, and PGB2 produced recognizable increases of frequency and amplitude of spontaneous contractions. The positive chrono- and inotropic responses were enhanced with increasing concentration of the PGs from 10(-8) to 10(-6) M. Both PGE2 and PGI2 in a concentration range from 10(-8) to 10(-6) M caused dose-related reductions in the amplitude of spontaneous contractions. No decrease in contraction rhythm was observed by the administration of PGI2 and PGE2 at concentrations lower than 5 X 10(-7)M. All of the above-mentioned responses induced by PGF2 alpha, PGA2, PGB2, PGI2, and PGE2 were not inhibited by pretreatment with alpha- and beta-adrenergic blocking agents, muscarinic antagonist, antihistamics, and serotonic antagonist. These findings suggest that PGF2 alpha, PGA2, and PGB2 in a low concentration may facilitate lymph flow of bovine mesenteric lymphatics in the living body, since the spontaneous contractions of lymphatic smooth muscle may drive lymph centripetally in the presence of direction valves. On the other hand, PGI2 and PGE2 may cause an inhibition of lymph transport.

Adrenergic alpha-Antagonists↗