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T Semba

Publications and source records attributed to T Semba.

At least 37 records · Page 2Linked to original sources
PubMed1990

A protein recognized by antibodies to Asp-Asp-Asp-Glu-Asp shows specific binding activity to heterogeneous nuclear transport signals.

Nuclear proteins contain a signal, termed the nuclear transport signal, that specifies their selective transport into the nucleus. Previously we reported that antibodies to Asp-Asp-Asp-Glu-Asp (DDDED) inhibited nuclear transport of nuclear proteins in vivo. We therefore tried to detect a cellular receptor of nuclear transport signals as a protein that reacted with both anti-DDDED antibody and nuclear transport signal sequences. Using two steps of affinity chromatography, anti-DDDED-Sepharose and nucleoplasmin-Sepharose, we obtained a protein of 69 kDa (p69) from the nuclear pore fraction that showed these characters. This p69 recognized by anti-DDDED antibody interacted specifically with SV40 large T antigen and nucleoplasmin transport signals.

Amino Acid Sequence↗
PubMed1990

Protein disulfide-isomerase in rat exocrine pancreatic cells is exported from the endoplasmic reticulum despite possessing the retention signal.

Recently we found by immunogold electron microscopy that protein disulfide-isomerase (PDI), a major resident protein in the lumen of the endoplasmic reticulum (ER) of many cells, is exceptionally localized in rat exocrine pancreatic cells not only in the ER but also in plasma membranes and other organelles along secretory pathway (Akagi, S., Yamamoto, A., Yoshimori, T., Masaki, R., Ogawa, R., and Tashiro, Y. (1988) J. Histochem. Cytochem. 36, 1069-1074). These observations suggest that another type of PDI, e.g. one with a defective ER retention signal, might exist and be transported in the exocrine pancreatic cells. We therefore compared biochemical and immunochemical properties of the transported PDI with the authentic ER resident PDI. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, peptide mapping, urea-polyacrylamide gel electrophoresis, and isoelectric focusing showed that the former was indistinguishable from the latter. We prepared a polyclonal antibody against the synthetic hexapeptide, which corresponds to the carboxyl terminus of PDI containing the putative ER retention signal "KDEL." The epitopes of this antibody (anti-KDEL antibody) were located within the KDEL sequence. Anti-KDEL antibody reacted with PDI in both the plasma membranes and the ER of rat pancreatic cells in immunoblot analysis as well as in immunogold electron microscopy. These results suggest that PDI exported from the ER to the plasma membranes in rat exocrine pancreatic cells possesses the KDEL sequence.

Amino Acid Isomerases↗
PubMed1989

Evidence for an intraluminal mediator in rat pancreatic enzyme secretion: reconstitution of the pancreatic response with dietary protein, trypsin and the monitor peptide.

New evidence has been obtained suggesting that the "monitor" peptide is an essential intraluminal mediator in the stimulation of pancreatic enzyme secretion in response to protein intake in rats. Experiments were performed in vivo using a mixture of 50 mg of ovalbumin, alpha-lactalbumin or casein, 2 micrograms of purified protease-sensitive, cholecystokinin-releasing monitor peptide and 1 mg of porcine trypsin which was infused by cannula into the duodenum of atropine-treated rats. The small intestine had previously been washed with bicarbonate to eliminate proteases and the pancreatic juice was diverted. The amount of trypsin secreted in 2 h was comparable to that of rats in which the pancreatic juice was returned into the duodenum. However, in the presence of a monitor peptide--specific antibody which recognizes the N-terminal region of the peptide, the monitor peptide did not induce any pancreatic response. Therefore, the characteristic pattern of pancreatic enzyme secretion in response to protein intake can be reproduced by infusing only three components--dietary proteins, porcine trypsin and the purified monitor peptide.

Animals↗
PubMed1988

A monoclonal antibody against dentin phosphophoryn recognizes a bone protein(s) appearing at the beginning of ossification.

Decalcified and nondecalcified sections of fetal bovine tibia were stained immunohistochemically with a monoclonal antibody against dentin phosphophoryn. In the epiphyseal portion of the long bone, osteoblasts, osteocytes and the bone matrix were stained, but chondrocytes and the cartilage matrix were not. Similar staining was observed in the epiphyseal and diaphyseal portions of bones. These findings suggest that a protein(s) with the same epitope as phosphophoryn may be synthesized and secreted by osteoblasts at the beginning of ossification and may be involved in mineralization of bone tissue. On Western blots of proteins extracted from fetal bovine bone, the antibody reacted with two bands of molecular weights of about 71,000 and 63,000. These proteins and antibody(s) to the proteins may be useful for detection of the phenotype of osteogenesis.

Animals↗
PubMed1988

Preparation of a verifiable peptide-protein immunogen: direction-controlled conjugation of a synthetic fragment of the monitor peptide with myoglobin and application for sequence analysis.

A useful method for preparing a synthetic peptide-carrying protein for specific antibody production was established. The monitor peptide is a trypsin-sensitive cholecystokinin-releasing peptide purified from rat pancreatic juice on the basis of its stimulatory activity toward pancreatic enzyme secretion. The NH2-terminus fragment of the monitor peptide (residues 1-14) was synthesized by a solid phase method. Cysteine at the COOH terminus of the fragment was conjugated with amino groups of myoglobin using a hetero-bifunctional reagent. Sequence analysis of the fragment-myoglobin conjugate indicated that the peptide/myoglobin conjugation ratio was about 1/1 (mol/mol). Antiserum against the conjugate from a rabbit effectively abolished the stimulatory activity of the monitor peptide in the rat small intestine.

Amino Acid Sequence↗
PubMed1988

Audiological characteristics of hearing loss following meningitis.

Meningitis is one of the leading causes of acquired sensorineural hearing loss in childhood, and many retrospective and prospective studies and case reports have been published. However, they have seldom discussed the nature of postmeningitic hearing loss from the audiological point of view. This study reports the results of audiological examinations performed on 5 patients suffering from hearing loss following meningitis. Extremely poor word discrimination scores as compared with pure-tone audiograms were common in all 5 cases. Type IV Békésy tracings were observed in 2 cases. Discrepancies between pure-tone audiograms and subjective hearing sensation and between pure-tone audiograms and ABR recordings were noted in 2 cases. These results suggest that varying degrees of retrocochlear involvement complicating the inner ear damage are the audiological characteristics of hearing loss following meningitis.

Audiometry, Evoked Response↗
PubMed1988

Treatment of hydropic patients by immunoglobulin with methyl B12.

Recently several investigations have been reported suggesting that the cause of endolymphatic hydrops might be an immunologic disorder of the endolymphatic space, including the endolymphatic sac. As the first choice in a conservative treatment by medication, the authors have used a combination of prednisolone and furosemide per os, which is rather safe and effective for hydrops patients in a subacute stage. However, some patients do not respond to this treatment or gradually become immune to this medication. With these patients, we have tried an intravenous administration of immunoglobulin G with methyl B12, expecting a curative effect on immunologic deficiency in the endolymphatic space. Compared with a group of patients without this treatment, the group receiving it showed rather good scores in hearing improvement; however, vertigo and tinnitus remained almost unchanged.

Adult↗
PubMed1980

[Effects of gamma-oryzanol on the movements of stomach and ileum in the dog (author's transl)].

Gastric and ileal movements were measured after administration of gamma-Oryzanol in the dog. 1. Gastric and ileal movement were enhanced after intravenous administration of 1 mg/kg body weight of gamma-Oryzanol. The higher dose of gamma-Oryzanol produced the shorter latency of these enhanced movements and thereafter, induced the inhibition of these movements. 2. When bilateral vagal nerves and the splanchnic nerves were previously transected or administered atropine, no enhancement of the gastric and ileal movement were observed by administration of gamma-Oryzanol. Furthermore, these enhanced movement produced with gamma-Oryzanol were abolished by atropine injection during these enhanced movement. 3. The inhibitory movement of the stomach and the ileum produced by administration of gamma-Oryzanol of 10 mg/kg body weight were reversely existed by the transection of vagal nerves in the cervical region or by administration of quinidine. These results indicate that gamma-Oryzanol produces the enhancement as well as inhibition of gastric and ileal movements. These effects may be produced by reaction to the central nervous system of the gastric and ileal movements.

Animals↗
PubMed1979

Effects of distension on mesenteric blood flow and O2 saturation of venous blood in the dog intestinal loop.

Arterial and venous blood flow and oxygen saturation of the venous blood in the mesenteric vessels arising from single mesenteric artery and vein to the intestinal loop in anesthetized dogs were measured simultaneously with systemic arterial blood pressure during distension of this loop. Mesenteric arterial blood flow decreased to the zero level, while mesenteric venous outflow increased to about twice the quiescent level at the onset of elevation of intraluminal pressure. However, during distension, the decreased arterial blood flow tended to increase, but the increased venous flow was reduced to one half of the quiescent level. Oxygen saturation of venous blood diminished initially and then increased progressively during distension. At the end of distension venous outflow stopped temporarily. After suspension of distension, arterial and venous flow and oxygen saturation increased beyond the quiescent level. These results may suggest that there is a by-pass or A-V anastomosis which cannot be compressed mechanically by elevation of intraluminal pressure.

Animals↗
PubMed1978

Atropine-resistant excitation of motility of the dog stomach and colon induced by stimulation of the extrinsic nerves and their centers.

The atropine-resistant contraction of the alimentary canal, first reported by CAMPBELL (1966) and subsequently confirmed by others, was examined in dog in vivo. The gastric and colonic motor excitations were examined by stimulating the extrinsic nerves, the medulla oblongata or the spinal cord and its roots. Prolonged stimulation of the vagus, medulla oblongata or splanchnic nerve, thoracic cord and its dorsal root produced excitation of the gastric motility even after intravenous injection of sufficient atropine, although the intensity and frequency of peristalsis were slightly reduced. Prolonged latent periods were characteristic of the atropine-resistant excitation in the stomach, the latency being 29.8--49.4 sec as compared to 2.3--14.5 sec in control (without atropine). On the other hand, the colonic excitation induced by the stimulation of the pelvic nerve, or sacral cord and its ventral root was not inhibited by atropine; no prolongation in latency and reduction of peristalsis was observed.

Animals↗
PubMed1977

Influence of intestinal inhibitory reflex on mesenteric blood flow through an intestinal segment of the dog.

The variations in both tonus and rhythmical motility of the intestinal musculature are known to affect profoundly intestinal blood flow. In the present study, the influence of marked reflex inhibition of intestinal tone on the blood flow through an intestinal segment was investigated in the dog. Experiments were performed under conditions of both normal circulation and cross-circulation. Inhibitory reflex was elicited by elevating the intraluminal pressure of a loop or by electrical stimulation of the intestinal wall. Fluctuations of blood flow during the intestinal inhibitory reflex were observed with normal circulation. Arterial and venous blood flows decreased in the initial period of intestinal relaxation, and recovered within 30 sec although reflex inhibition still remained. This is an autoregulatory escape phenomenon. In successive periods, arterial and venous blood flows decreased again due to "the venous-arteriolar response" and then recovered to the quiescent level. The decrease in venous blood flow corresponded to an increase of the degree of oxygen saturation in the venous blood. The decreases in arterial and venous blood flows were observed during the inhibitory reflex even when the intestinal circulation was maintained by the cross-circulation. Two different patterns, i.e., the parallel and reversed patterns, were distinguished in correlation with venous blood flow and oxygen saturation. The autoregulatory escape phenomenon could not be elicited in the experiments in the cross-circulation system because variation of the systemic blood pressure during inhibitory reflex was limited to +/-4%.

Animals↗
PubMed1975

[An atropine-resistant contraction of dog's stomach in response to stimulation of the vagus and splanchnic nerves (author's transl)].

1. A study was made in vivo experiments of a contraction of stomach of the dog to stimulation of the extrinsic nerves, medulla oblongata and thoracic cord in the presence of atropine. 2. An atropine-resistant contraction of stomach was produced without accompanying any preceding relaxation of stomach motility. It seems to deny that an atropine-resistant contraction appears to be a rebound phenomenon. 3. An atropine-resistant contraction was produced in prolonged stimulation. A delay of latency to produce a contraction of stomach was more than 27 sec and a contraction was decreased in amplitude and frequency in the presence of atropine.

Animals↗