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Biomedical subjects

T Chiba

Publications and source records attributed to T Chiba.

At least 631 records · Page 35Linked to original sources
PubMed1982

Substance P-like immunoreactive axon varicosities with synaptic junctions in the nucleus tractus solitarius of the rat.

Substance P-like immunoreactive axon varicosities form both Gray's type I and type II synaptic junctions to the dendrites and somata in the nucleus of the tractus solitarius of the rat. Peroxidase anti-peroxidase reaction products are observed mainly on the large dense-cored vesicles and in the axoplasm preferentially surrounding small clear vesicles. Labeled axon varicosities are filled with small clear vesicles of 50 nm in diameter.

Animals↗
PubMed1982

A new fucosyl antigen expressed on colon adenocarcinoma and embryonal carcinoma cells.

Carbohydrate antigens on the surface of mammalian cells have recently gained renewed interest because some are specifically expressed at certain stages of cellular differentiation. Most of the useful antibodies detecting such carbohydrate antigens have been monoclonal antibodies produced by the hybridoma technique using whole cells as the immunogen or the antibodies in the sera of some of human patients. Here we report that an antiserum raised against an unusual carbohydrate linkage prepared by organic synthesis can preferentially react with certain tumour cells. Thus, an antiserum against the Fuc alpha l leads to 3Gal linkage reacted with human colon adenocarcinoma cells and murine teratocarcinoma cells but reacted only with severely restricted regions in normal tissues.

Adenocarcinoma↗
PubMed1982

Ultrastructure of the regenerating growth cones of catecholamine nerve terminals in rat hypothalamic nuclei after 5,7-dihydroxytryptamine administration.

Ultrastructure of the regenerating growth cones of catecholamine axons is examined in the paraventricular nucleus and median eminence of the rat. Growth cones are observed during 1 to 4 months, and most frequently at 2 months, after the administration of 300 microgram of 5,7-DHT in the lateral ventricle. The growth cones of catecholamine axons are characterized by an accumulation of branching smooth endoplasmic reticula which contain dense material.

5,7-Dihydroxytryptamine↗
PubMed1982

Endocrine function of pancreas transplant: insulin, glucagon and somatostatin release from rat pancreatic isograft.

Using the whole pancreas transplantation model, we investigated the endocrine function of the isografted pancreatic A, B and D cells. The release of insulin, glucagon and somatostatin by the pancreatic grafts were examined and compared with those in normal rats with or without syngenic pancreas transplantation, using in vivo and in vitro systems. These studies demonstrate that the grafted pancreas maintained normal insulin, glucagon and somatostatin secretion after transplantation. This pancreatic graft may serve as a suitable experimental model for the studies on therapy for diabetes mellitus.

Animals↗
PubMed1982

A correlative quantitative study comparing the nerve fibers in the cervical sympathetic trunk and the locus of the somata from which they originate in the rat.

Correlative quantitative analyses were performed on the rat comparing the number of fibers in the cervical sympathetic trunk (CST) and the horseradish peroxidase (HRP)-labeled neurons in the superior cervical sympathetic ganglion (SCG), stellate ganglion, as well as in the spinal cord. The total number of nerve fibers in the left CST was 4180 +/- 169 (mean +/- S.E.M.) among which 92 +/- 3 (mean +/- S.E.M.) were myelinated. The diameter of unmyelinated fibers was 0.68 +/- 0.22 (mean +/- S.D.) microns and showed single-peaked distribution. After the application of HRP to the proximal cut end of the CST, labeled neurons were found in the stellate ganglion as well as in the ipsilateral spinal cord from C7 to T4 segments. The total number of HRP-labeled neurons in the spinal cord was 1334 +/- 45 (mean +/- S.E.M.) with the range between 844 and 1808. Ninety-nine percent of labeled neurons were located in the intermediolateral column and in the lateral funiculus while 1% were in the intercalated region and central autonomic area. Labeled neurons were encountered only sporadically in the dorsal root ganglia (DRG) from C8 to T3 level. After the application of HRP to the distal cut end of the CST, about 200 labeled neurons were observed in the caudal part of the SCG. The present results were discussed with special reference to the organization of the CST of the rat.

Animals↗
PubMed1982

Effect of long term bromocriptine treatment on glucose intolerance in acromegaly.

Blood glucose, plasma GH, insulin and glucagon levels during oral glucose tolerance test before and after treatment with bromocriptine (5-20 mg daily for 2-9 months) were investigated in eleven acromegalic patients with glucose intolerance. Nine out of 11 patients showed improvement or normalization in glucose tolerance after bromocriptine therapy. Basal levels of plasma GH were markedly decreased in 7 of 11 patients treated, although the improved glucose tolerance was not always associated with a drop of basal plasma GH levels. In contrast, basal plasma glucagon level showed a distinct fall in all the patients whose glucose tolerance was improved, but unchanged in whom glucose tolerance was not ameliorated. The mean values of plasma GH and glucagon after oral glucose load were significantly lower during bromocriptine therapy than those before the treatment, respectively. Basal levels of plasma insulin and its response to glucose load did not change after bromocriptine treatment. Bromocriptine thus appears to be a good alternative in the treatment of glucose intolerance in acromegalic patients and the improvement of glucose tolerance by bromocriptine may be related to the reduction in plasma glucagon levels. The possibility, however, is not excluded that a decrease by bromocriptine in the total daily GH secretion is a cause of the improved glucose tolerance.

Acromegaly↗
PubMed1982

[Histochemical study of glycosaminoglycan in Wilms tumors of rats and rabbits and fetal kidneys of rats].

Histochemical studies were performed on glycosaminoglycan (GAG) components in Wilms tumors of rats and rabbits and fetal kidneys of rats. 1. Wilms tumors. The interstitial components had an intense stainability with Alcian blue, and digestion test with hyaluronidase and chondroitinase was intensely positive. The epithelial tumor cells, showing a tubular pattern, were also stained with Alcian blue. The enzyme-digestion test was positive in the basal portion of the tumor cells, whereas it was negative in the free surface of the cells. 2. Rat kidneys. In fetal rats, the epithelial cells as well as the interstitial components were stained with Alcian blue, and the enzyme-digestion test was intensely positive. However, in adult rats, Alcian blue-stainability in the free surface of the tubular epithelium was not abolished by treatment with hyaluronidase and chondroitinase. The substance in the free surface seemed to be consisted mainly of heparan sulfate. Although the physiological significance of GAG in the cell surface cannot be deduced, it is quite conceivable that GAG, especially heparan sulfate, plays an important role in fluid absorption and transportation.

Animals↗
PubMed1982

Studies on recovery of liver function of operated biliary atresia.

Serial liver function studies were analyzed in 42 biliary atresia patients who had undergone portoenterostomy. Values for serum bilirubin, ZTT, TTT, and gamma globulin returned to normal levels three months after operation in patients with good bile excretion. These tests remained abnormal in those with poor bile output. Alkaline phosphatase and serum transaminase values remained high during the early postoperative period, requiring a much longer duration to return to normal. The biological activity of sulfobenzyl penicillin (SBPC) in the serum and bile was determined by serial broth dilution in 15 children with biliary atresia. Eleven patients were studied 10 days to 2 weeks after an apparent successful portoenterosotomy while four others were clinically well and anicteric three to four years postoperatively. The biliary concentration of SBPC was very low despite good bile output during the early postoperative period. The SBPC levels increased three time during the remote postoperative period. The bile concentration of SBPC is lower than normal, however, and it seems that the ability of the liver to excrete this material may never reach normal levels despite apparent good clinical hepatic function.

Alanine Transaminase↗
PubMed1982

Tolbutamide stimulates gastric somatostatin release from isolated perfused rat stomach.

The effect of tolbutamide on somatostatin release from the isolated perfused stomach was investigated in both normal and streptozotocin-diabetic rats. Tolbutamide (10, 100, and 1000 microgram/ml) evoked a significant and dose-dependent increase in gastric somatostatin release. The tolbutamide (100 microgram/ml)-induced gastric somatostatin secretion was not influenced by differences in glucose concentration (1.5, 5.5, and 16.5 mM) throughout the perfusion period. Tolbutamide (100 microgram/ml)-induced gastric somatostatin release in streptozotocin-diabetic rats was significantly higher than in normal rats. Thus, tolbutamide is a potent secretagogue for gastric somatostatin secretion, and this effect is more prominent in diabetic animals.

Animals↗
PubMed1981

Architecture and synaptic relationships in the intermediolateral nucleus of the thoracic spinal cord of the rat: HRP labelling, catecholamine histochemistry and electron microscopic studies.

The organization of the intermediolateral nucleus (IML) of the thoracic spinal cord was examined using glyoxylic acid-induced fluorescence histochemistry, retrograde horseradish peroxidase (HRP) labelling and electron microscopy. In serial sections of T2, it was found that the distribution of catecholamine nerve terminals was intimately related to the neuronal perikarya of IML. Potassium permanganate fixation and 5-hydroxydopamine treatment revealed small dense-cored vesicles in axon varicosities with or without synaptic specializations. A gelatinous region, composed of small diameter dendrites and unmyelinated axons, formed a narrow longitudinal bundle in the centre of the nucleus. The population of the axon varicosities in the IML was 0.17 +/- 0.02/micrometer2 in 75 nm sections. The average size of the axon varicosities with flat synaptic vesicles was 1.44 +/- 0.05 micrometers2 and that of varicosities with spherical vesicles was 0.97 +/- 0.02 micrometers2. After HRP injection into the superior cervical ganglion, ipsilateral IML neurons were labelled in T1-T3 segments of the spinal cord. Axon varicosities with flat and others with spherical synaptic vesicles synapsing on the dendrites labelled by HRP. Among axon varicosities synapsing on the preganglionic sympathetic neurons, 74.8 +/- 7.1% at axo-somatic synapses and 46.0 +/- 6.7% at synapses on proximal dendrites contained flat synaptic vesicles.

Animals↗
PubMed1981

Characteristics of 106 spontaneous mammary tumours appearing in Sprague-Dawley female rats.

Pathological studies were undertaken on 106 mammary tumours (89 benign, 17 malignant) appearing spontaneously in 95 normal female Sprague-Dawley rats which were killed at Day 756. The benign tumours comprised those with a predominant acinar hyperplasia and those with adenomatous or fibroadenomatous pattern. No significant differences were found histochemically between the acinar cells of the benign tumours and of the lactating gland, except that the amount of fibrous interstitial connective tissue was larger in the former. 3H- or 35S-glycosaminoglycan synthesis by the benign tumours was found to be much higher. The prolactin value in the plasma of the benign-tumour-bearing rats was about 27 times that of 6-month-old virgin rats, and similar to that of rats on the 7th day post partum. Carcinomatous proliferation of tubuloacinar cells could be seen in 5 of the 89 benign tumours. The incidence of benign tumours increases with the age of the rats.

Animals↗
PubMed1981

Effect of intraventricular injection of neurotensin and other various bioactive peptides on plasma immunoreactive somatostatin levels in rat hypophysial portal blood.

The role of various bioactive peptides in the control of secretion of hypothalamic somatostatin into the hypophysial portal blood was examined in anesthetized rats. Hypophysial portal blood was withdrawn at a rate of 5.0 microliter/min into a chilled tube through a cannula placed over the stump of the pituitary stalk and segmented every 20 min by air bubbles. Immunoreactive somatostatin (IRS) in the plasma was extracted with acetic acid and acetone and quantified by RIA. Basal levels (mean +/- SE) of plasma IRS in the hypophysial portal blood were 646 +/- 36 and 317 +/- 44 pg/ml in urethane- and pentobarbital-anesthetized rats, respectively. Under urethane anesthesia, injection of synthetic neurotensin into the lateral ventricle at various doses in the range of 0.016--2 microgram/rat caused a significant and dose-related increase of plasma IRS levels in the hypophysial portal blood, and this effect of neurotensin was significantly (P less than 0.05) suppressed by pretreatment with diphenhydramine (1 mg/100 g BW, iv), a histamine receptor blocker. Enhancement of IRS release by neurotensin was also observed in pentobarbital-anesthetized rats. Intraventricular injection of substance P (10 microgram/rat), beta-endorphin (1 and 5 microgram/rat), or [Met5]enkephalin had no effect on the level of somatostatin in the hypophysial portal blood of urethane-anesthetized rats. These results suggest a release of hypothalamic somatostatin into the hypophysial portal blood in response to intraventricular administration of neurotensin, probably by a histaminergic mechanism.

Animals↗
PubMed1981

Stimulation by bombesin of immunoreactive somatostatin release into rat hypophysial portal blood.

Bombesin was injected into the cerebral ventricle of male rats anesthetized with urethane to study its effect on plasma levels of immunoreactive somatostatin (IRS) in hypophysial portal and jugular blood. An intraventricular injection of bombesin (0.2 and 2 micrograms/rat) caused a significant and dose-related increase in plasma IRS in hypophysial portal blood but not in jugular blood. Although bombesin placed into the cerebral ventricle is known to stimulate glucagon and epinephrine release, an iv injection of glucagon (100 micrograms/100 g BW) or epinephrine (2.5 micrograms/100 g BW) did not cause any significant changes in plasma IRS levels in hypophysial portal and jugular blood, suggesting that these substances do not mediate bombesin stimulation of portal IRS release. Pretreatment with naloxone (75 micrograms/100 g BW, iv) failed to affect the portal IRS release induced by bombesin (2 micrograms/rat), indicating that the opiate receptor is not likely to be involved in this reaction. To ascertain whether IRS released by bombesin into hypophysial portal blood is biologically active, the effect of bombesin on the plasma GH level was then examined. Bombesin (2 micrograms/rat) injected intraventricularly completely suppressed the rise of plasma GH after the intraventricular injection of beta-endorphin (1 microgram/rat) or the iv injection of prostaglandin E1 (5 micrograms/100 g BW). Bombesin thus appears to stimulate the secretion of IRS, and probably biologically active somatostatin as well, from the hypothalamus into hypophysial portal blood, thereby inhibiting GH release from the anterior pituitary.

Animals↗