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Biomedical subjects

T Chiba

Publications and source records attributed to T Chiba.

At least 505 records · Page 28Linked to original sources
PubMed1990

[Radiation-induced malignant skin tumors in the hands of five doctors].

Radiation-induced malignant skin tumors in the hands in 3 surgeons, one physician, and one dentist are reported. The latent period of the irradiation ranged between 16 years and 34 years. Clinically, small keratotic lesions were seen in 4 doctors and a large tumor the remaining doctor. On histological examination, one of the tumors was a squamous cell carcinoma, 3 were carcinomas in situ, and the fifth was a basal cell carcinoma with a squamous cell carcinoma. While the occupational hazard of developing malignant skin tumors following irradiation have decreased recently, this paper emphasizes precautions should be taken when diagnosing and caring for cancer patients.

Adult↗
PubMed1990

[Computed tomography for the assessment of pelvic lymph node metastasis in cases of uterine cervical carcinoma].

Seventy-six patients with cervical cancers underwent preoperative abdominopelvic computed tomography before a pelvic lymphadenectomy to evaluate the efficacy of computed tomography in assessing pelvic lymph node metastases. The sensitivity and the specificity of computed tomography for detecting pelvic lymph node metastases were judged to be 70.6 and 89.8%, respectively. In 54 patients in stage Ib or IIa of the disease, the sensitivity and specificity were 85.7 and 91.5%, respectively. Although inaccuracies could be caused by normal-sized metastasized lymph nodes and by enlarged lymph nodes with reactive hyperplasia, computed tomography was found to be a useful method of detecting a pelvic lymph node metastasis.

Female↗
PubMed1990

[A clinical study on multiple tumor markers following therapy in patients with uterine cervical carcinoma].

In order to evaluate the clinical significance of multiple tumor markers, plasma levels of carcino-embryonic antigen (CEA), squamous cell carcinoma-related antigen (SCC), tissue polypeptide antigen (TPA) and immunosuppressive acidic protein (IAP) were measured before and after treatment in 136 patients (89 surgery cases and 47 radiotherapy cases). The patients had invasive cervical carcinoma (stages I-IV). The effect of radiotherapy was examined by cytology and biopsies obtained by colposcopy. For CEA, SCC and TPA there was a significant reduction (p less than 0.01) in values between the pretreatment and posttreatment periods, but plasma IAP was transiently increased after operation. Cytology and histology revealed negative rates of 95.6% and 86.7%, respectively, after radiotherapy. Regarding recurrence, for the negative groups and positive groups plasma CEA, SCC, TPA and IAP were determined in 24 patients with stage IIIb before radiotherapy. Only the CEA concentration showed a good correlation with the outcome (p less than 0.01). Effective serial plasma determinations of CEA, SCC and TPA in patients with cervical carcinoma following therapy may often be useful in the evaluation of therapy as well as in the earlier detection of recurrent disease.

Antigens, Neoplasm↗
PubMed1989

Direct synaptic contacts of 5-hydroxytryptamine-, neuropeptide Y-, and somatostatin-immunoreactive nerve terminals on the preganglionic sympathetic neurons of the guinea pig.

Direct synapses from 5-hydroxytryptamine-, neuropeptide Y-, and somatostatin-immunoreactive axon varicosities to the preganglionic sympathetic neurons retrogradely labeled with horseradish peroxidase were observed in the thoracic intermediolateral nucleus of the guinea pig. Symmetric synapses were predominant and both axo-dendritic and axo-somatic contacts were observed.

Animals↗
PubMed1989

An immunohistochemical observation of polypeptides and monoamines in the nucleus preopticus medianus of the rat.

A detailed regional distribution of nerve cells and terminals immunoreactive to polypeptides or monoamines was examined in the 5 subdivisions (rostral, mid-dorsal, mid-ventral, caudo-dorsal and caudo-ventral parts) of the nucleus preopticus medianus (POMe) of the rat. In general, immunoreactive nerve cells and terminals are more numerous in the ventral parts of the middle and caudal POMe. Nerve cells immunoreactive to neurotensin (NT), Met-enkephalin-Arg6-Gly7-Leu8 (mENK8) or cholecystokinin-octapeptide (CCK8) are distributed throughout the POMe, while those immunoreactive to luteinizing hormone-releasing hormone (LHRH) are found in the rostral and middle POMe. Nerve cells immunoreactive to substance P (SP) are seen in the middle and caudal POMe and those immunoreactive to somatostatin (SRIF) are scattered in the middle part of the nucleus. The densities of nerve terminals immunoreactive to neuropeptide tyrosine, mENK8, SP or noradrenaline are high throughout the POMe, while nerve terminals immunoreactive to CCK8, LHRH, NT, SRIF or vasoactive intestinal polypeptide are moderate and those immunoreactive to calcitonin gene-related peptide, serotonin or dopamine are sparse. This varied distributional pattern of immunoreactive nerve cells and terminals suggests regional differences in function within the POMe.

Animals↗
PubMed1989

Coexistence of multiple peptides in small intensely fluorescent (SIF) cells of inferior mesenteric ganglion of the guinea pig.

Coexistence of peptides in the small intensely fluorescent cells was demonstrated by immunocytochemistry for met-enkephalin-Arg-Gly-Leu, vasoactive intestinal polypeptide, somatostatin, neuropeptide Y and dynorphin. In the extreme example, a single cell was immunoreactive to all 5 peptides examined. Four peptides coexisted in 8% and three peptides in 13% of SIF cells. In 10% of SIF cells no peptide immunoreactivity could be detected. The most prevalent peptide was met-enkephalin (in 46% of cells), then vasoactive intestinal polypeptide (45%), somatostatin (39%), neuropeptide Y (31%) and dynorphin (24%). Met-enkephalin and vasoactive intestinal polypeptide coexisted most commonly (25%).

Animals↗
PubMed1989

Mechanism for increase of gastrin release by secretin in Zollinger-Ellison syndrome.

In patients with Zollinger-Ellison syndrome, serum gastrin level is increased by secretin and is decreased by somatostatin. To elucidate the cellular mechanism for these actions, we investigated the direct effects of secretin and somatostatin on dispersed gastrinoma cells from a patient with Zollinger-Ellison syndrome. In the presence of 3-isobutyl-1-methylxanthine, secretin significantly stimulated gastrin release from dispersed gastrinoma cells, which was inhibited by somatostatin. In the presence of guanosine 5'-triphosphate, furthermore, secretin enhanced adenylate cyclase activation in the membranes from these cells, and this activation was reduced by somatostatin, whereas neither secretin nor somatostatin affected inositol phospholipid turnover. On the other hand, removal of guanosine 5'-triphosphate from incubation medium abolished both the stimulatory effect of secretin and the inhibitory effect of somatostatin on adenylate cyclase activation. Furthermore, pertussis toxin pretreatment reversed the ability of somatostatin to inhibit secretin-induced increase in gastrin release and activation of adenylate cyclase. Thus, in this gastrinoma patient, secretin and somatostatin appeared to act directly on gastrinoma cells to stimulate and inhibit gastrin secretion, respectively, by modulating adenylate cyclase activation, probably via guanine nucleotide-binding proteins.

Adenylyl Cyclases↗
PubMed1989

Prostaglandin E2 and F2 alpha inhibit growth of human gastric carcinoma cell line KATO III with simultaneous stimulation of cyclic AMP production.

The effects of prostaglandins (PGs) on the growth of human gastric carcinoma cell line KATO III were investigated. PGE2 as well as PGF2 alpha significantly and dose-dependently inhibited the growth of this gastric carcinoma cell line (PGE2 greater than PGF2 alpha). This inhibition of cell growth by the PGs was associated with the increase in cyclic AMP production (PGE2 greater than PGF2 alpha), whereas inositol-phospholipid turnover was not affected by either PGE2 or PGF2 alpha as assessed by the formation of 3H-inositol phosphates. Furthermore, the proliferation of these gastric carcinoma cells was also suppressed by the administration of forskolin as well as of dibutyryl cyclic AMP. These results suggest that PGE2 and PGF2 alpha inhibit the growth of cultured human gastric carcinoma cells KATO III via stimulation of cyclic AMP production.

Bucladesine↗
PubMed1989

Presence and release of calcitonin gene-related peptide in rat stomach.

Immunoreactive (IR)-calcitonin gene-related peptide (CGRP) was identified throughout the entire stomach of rats, being most highly concentrated in the pyloric region, and the concentrations in muscular layers being higher than those in mucosal layers. In addition, IR-CGRP was also present in the venous effluent from isolated perfused rat stomach, and its release was stimulated by dibutyryl cyclic AMP or theophylline but not by glucagon. Gel chromatography as well as HPLC of both tissue extracts and gastric perfusate showed three identical major peaks of IR-CGRP, one of which coeluted with synthetic CGRP. These results suggest that CGRP in the stomach plays a role in the regulation of gastric function.

Animals↗
PubMed1989

Coexistence of varying combinations of neuropeptides with 5-hydroxytryptamine in neurons of the raphe pallidus et obscurus projecting to the spinal cord.

The coexistence of varying combinations of substance P (SP), somatostatin (SOM), thyrotropin-releasing hormone (TRH) and met-enkephalin-Arg-Gly-Leu (ENK) with 5-hydroxytryptamine (5-HT) as semiquantitatively revealed by immunocytochemistry in neuronal perikarya of the raphe pallidus et obscurus in the guinea-pig was analyzed. SOM coexisted most frequently with 5-HT, followed by SP, ENK and TRH. Many 5-HT neurons were immunoreactive to 2 or more peptides such as SP/SOM, SOM/ENK, SP/ENK, SOM/TRH, SP/TRH or SOM/SP/ENK. Most of these neurons were shown to project to the spinal cord by retrograde HRP labeling combined with immunocytochemistry. After hemisection of the cervical spinal cord at the C5 level, ENK and 5-HT immunoreactive nerve terminals in the ipsilateral intermediolateral nucleus of the thoracic spinal cord were decreased in number. The results indicate that neurons in the raphe pallidus et obscurus projecting to the spinal cord can be classified into subpopulations according to which peptides coexist with 5-HT, and may have different functions.

Animals↗
PubMed1989

Synaptic structure and axon collaterals of type B neurons in bullfrog sympathetic ganglia: intracellular horseradish peroxidase (HRP)-labeling study.

Type B neurons of the bullfrog sympathetic ganglia were examined to confirm the existence of axon collaterals and the distribution of synaptic contacts using the intracellular horseradish peroxidase (HRP) labeling method. The mean diameter of the perikarya was 60.8 (+/- 11.5 standard deviation; n = 36) X 43.8 (+/- 11.3) microns and the mean diameter of the initial segments of axons was 6.0 (+/- 1.8; n = 36) microns. Axon collaterals were found in 6 cells among 36 examined. They branched from axons at 61-167 microns from the perikaryon of origin. Short-axon collaterals containing vesicles (diameter: about 70 nm) were also observed to protrude from the stem axons. Spine-like processes were observed from the cell soma, axon hillock and the initial segment of the axon. They enclosed synaptic axon varicosities, or extended into the extracellular space without any synaptic contact. Serial sections revealed 171 axon varicosities in contact with a single ganglion cell; 32 (18.7%) varicosities were seen on the somata. 66 (38.6%) on the axon hillock and 73 (42.7%) on the initial segment of the axon which extended 100 microns from the perikaryon. Synaptic terminals were also found on the axon as far as 494 microns from the cell body of origin. These findings would provide a morphological basis for interaction between bullfrog sympathetic neurons at pre- or postsynaptic sites.

Animals↗
PubMed1989

Surgical limitation for biliary atresia: indication for liver transplantation.

Of 245 patients undergoing corrective operations for biliary atresia, jaundice was cleared in 113. In January 1988, 84 of them were living and free of jaundice and the other 19 were alive with jaundice. A vast majority of long-term survivors showed normal growth and development, and were leading normal lives for their respective ages. Portal hypertension, a common late complication, improved spontaneously or after sclerotherapy in jaundice-free patients. Therefore, liver transplantation is not recommended for jaundice-free patients even with esophageal varices. Patients with persistent severe jaundice (serum bilirubin over 10 mg/dL) and those with moderate jaundice (serum bilirubin 5 to 10 mg/dL) and severe esophageal varices require liver transplantation. Patients with moderate jaundice having no or slight varices should be carefully followed. When varices become worse or serum bilirubin rises, liver transplantation is indicated. Patients with mild jaundice (serum bilirubin lower than 5 mg/dL) have a possibility of improvement in their condition before the age of 15 years, and are not recommended for liver transplantation. The high value of the lowest postoperative bilirubin level suggests the necessity of liver transplantation in early childhood. Liver transplantation as the primary treatment for biliary atresia may be indicated only for patients over 120 days of age with an enlarged and hard liver.

Adolescent↗
PubMed1989

Bronchopulmonary foregut malformation in 3 infants--with special references to cases in childhood.

We encountered three infant patients with bronchopulmonary foregut malformation. Two of them were associated with oesophageal atresia, and the remaining one with jejunal atresia. Two of the patients showed total lung sequestration, and the rest showed intralobar sequestration. 37 paediatric cases of this type were reviewed from the literature. Total lung sequestration was observed in 19 of the 37 cases, showing an increase in the incidence in comparison with that reported previously. There were also 7 cases associated with oesophageal atresia.

Abnormalities, Multiple↗
PubMed1989

Physical, enzymatic, and contractile properties of brain myosin with anti-brain myosin Fab fragment bound on its tail.

An antibody obtained by immunizing a rabbit with purified bovine brain myosin was found to react with the tail portion of the myosin heavy chain. An Fab fragment obtained by limited papain digestion of the antibody was allowed to bind to brain myosin, and the complex of the Fab fragment and brain myosin (Fab-myosin) was isolated. On examination of the rotary-shadowed Fab-myosin by electron microscopy, most of the Fab fragment was located on the middle to C-terminal regions of the tails of the myosin molecules. The solubility of Fab-myosin in low salt solutions was higher than that of control brain myosin. Fab-myosin was found to form small irregular aggregates in low salt solutions instead of regular bipolar filaments, and the relative population of the monomeric form of myosin molecules observed for the Fab-myosin was much larger than that observed for the control myosin. The actin-activated Mg2+-ATPase activity of Fab-myosin was stimulated two- to threefold by phosphorylation of the light chains with myosin light chain kinase, as observed for the control brain myosin. Furthermore, the levels of the ATPase activity of the phosphorylated and dephosphorylated Fab-myosins were similar to those of the phosphorylated and dephosphorylated control myosins, respectively. The superprecipitation activity of Fab-myosin was also highly dependent on phosphorylation of the light chains. Although control brain myosin formed a large superprecipitate network which contracted to a dense particle, Fab-myosin generated only numerous tiny superprecipitates under the same conditions. From these results it was deduced that a regular filamentous state of brain myosin was not prerequisite for its actin-activated Mg2+-ATPase and superprecipitation activities but was indispensable for the formation of a large and well contractible superprecipitate.

Animals↗
PubMed1989

Clear cell carcinoma of the endometrium with lipid-producing activity. Histologic and ultrastructural study suggesting a unique neoplasm.

A case of clear cell carcinoma of the endometrium with lipid-producing activity in a 59-year-old woman was studied by light and electron microscopy. Following a modified radical hysterectomy, the plasma level of cancer antigen 125 (CA125) decreased abruptly. Histologically, the tumor was composed of clusters of large, polygonal cells with either clear or eosinophilic cytoplasm, showing distinct borders and bizarre, pleomorphic nuclei divided into many groups by the connective tissue elements. Abundant lipid droplets in the neoplastic cells were observed by Sudan III stain, and the CA125 antigen was demonstrated in the neoplastic cells. Mitotic figures were difficult to find. Electron microscopically, the tumor cell nuclei were oval or polygonal and sometimes slightly invaginated, with a few prominent nucleoli. The cytoplasm contained abundant lipid droplets, rough endoplasmic reticulum, rod-shaped to round mitochondria, Golgi apparatus, glycogen particles, and free ribosomes. A few small lumina containing microvilli were recognized. These observations suggest that this lesion is a unique type of clear cell carcinoma of the endometrium originating from Müllerian epithelium and possessing lipid-producing activity.

Adenocarcinoma↗
PubMed1989

Long-term follow-up study of patients with cholangitis after successful Kasai operation in biliary atresia: selection of recipients for liver transplantation.

Since the introduction of cyclosporine A, liver transplantation has become accepted as the therapy for end-stage liver disease. However, there are no definite criteria for liver replacement in biliary atresia. We investigated (a) the survival rate after hepatic portoenterostomy (n = 131), (b) liver function tests in fatal cases after an initially successful hepatic portoenterostomy (n = 9), and (c) liver function tests in the patients with episodes of cholangitis after a successful surgical treatment (n = 8). Patients with persisting jaundice after the surgery cannot be expected to survive long, and therefore they definitely should undergo liver transplantation. When total bilirubin concentration was above 10 mg/dl in patients with cholangitis after a successful operation, conservative therapy had almost no effect. Therefore, patients with total bilirubin levels above 10 mg/dl should be considered for liver transplantation. Of the liver function tests, only total bilirubin was reliable as a marker for hepatic failure in the end stage of biliary atresia. Prolongation of thrombo test and episodes of gastrointestinal bleeding also were used in selection of patients for liver replacement.

Biliary Atresia↗
PubMed1989

Calcitonin gene-related peptide receptor antagonist human CGRP-(8-37).

From this study, we predicted that the human calcitonin gene-related peptide (hCGRP) fragment hCGRP-(8-37) would be a selective antagonist for CGRP receptors but an agonist for calcitonin (CT) receptors. In rat liver plasma membrane, where CGRP receptors predominate and CT appears to act through these receptors, hCGRP-(8-37) dose dependently displaced 125I-[Tyr0]rat CGRP binding. However, hCGRP-(8-37) had no effect on adenylate cyclase activity in liver plasma membrane. Furthermore, hCGRP-(8-37) inhibited adenylate cyclase activation induced not only by hCGRP but also by hCT. On the other hand, in LLC-PK1 cells, where calcitonin receptors are abundant and CGRP appears to act via these receptors, the bindings of 125I-[Tyr0]rat CGRP and 125I-hCT were both inhibited by hCGRP-(8-37). In contrast to liver membranes, interaction of hCGRP-(8-37) with these receptors led to stimulation of adenosine 3',5'-cyclic monophosphate (cAMP) production in LLC-PK1 cells, and moreover, this fragment did not inhibit the increased production of cAMP induced not only by hCT but also by hCGRP. Thus hCGRP-(8-37) appears to be a useful tool for determining whether the action of CGRP as well as that of CT is mediated via specific CGRP receptors or CT receptors.

Adenylyl Cyclases↗