Biomedical subjects

T Chiba

Publications and source records attributed to T Chiba.

At least 487 records · Page 27Linked to original sources

PubMed1990

Formation of synaptic graft-host connections by noradrenergic locus coeruleus neurons transplanted into the adult rat hippocampus.

Transplants of cell suspension obtained from the locus coeruleus region of 13- to 14-day-old rat fetuses were implanted into the hippocampal formation of intact adult rats or rats from which the noradrenergic afferents to the hippocampus had been removed by bilateral 6-hydroxydopamine (6-OHDA) injections into the dorsal tegmental noradrenergic bundle. The growth noradrenergic axons into the host hippocampus from the implant was studied at 4-8 months after surgery by immunohistochemistry using antisera raised against tyrosine hydroxylase or noradrenaline. In the animals with an intact noradrenergic system the host noradrenergic afferents were removed by bilateral dorsal bundle lesions 2 weeks before sacrifice. Fine axon-like fibers (diameter about 0.3 micron) and thick dendrite-like fibers (diameter about 1.3 micron), labeled immunohistochemically, were abundant and spread far from the graft. By electron microscopy, immunolabeled axon-like fibers formed mostly symmetrical synaptic contacts with nonlabeled spines and shafts of dendrites in the host. Labeled dendrite-like fibers of presumed graft origin penetrated deep into the host neuropil and received abundant afferents from nonlabeled axon terminals. The extent of graft-derived noradrenergic axons and the synapses established with the host hippocampal neurons were similar in the chronically denervated animals and in the animals where the intrinsic noradrenergic afferents had been left intact until 2 weeks before sacrifice. The results show that implanted embryonic noradrenergic neurons are able to innervate the hippocampus in both the presence and the absence of an intact intrinsic noradrenergic innervation and that the ingrowing axons form abundant synaptic connections with the host hippocampal neurons under both conditions. Dendritic processes from the grafted noradrenergic neurons that extend deep into the host tissue may receive a reciprocal synaptic host afferent input.

Animals↗

PubMed1990

Cholangiographic study of the pancreaticobiliary ductal junction in biliary atresia.

The size and arrangement of each component of pancreaticobiliary ductal junction was investigated in 28 cases with biliary atresia in which cholangiography allowed visualization of the common bile duct, pancreatic duct, and duodenum and in which relevant data were available. As controls, seven cases of neonatal hepatitis and eight cases of intrahepatic bile duct hypoplasia were also studied. The following results were obtained. (1) The diameter of the common bile duct was shortest in biliary atresia, the value corresponding to about one-third of that for neonatal hepatitis. (2) The common bile duct was visualized in 100% of cases of intrahepatic bile duct hypoplasia and 78% of cases of biliary atresia, whereas the corresponding percentage was only 43% for neonatal hepatitis. The mean length of the common channel in cases of biliary atresia and that of intrahepatic bile duct hypoplasia was about 5 mm, which was longer than that of neonatal hepatitis. (3) The pancreatic duct type, in which the pancreatic duct merged into the bile duct, was frequent in cases of biliary atresia.

Bile Duct Diseases↗

PubMed1990

Surgical treatment of congenital dilatation of the bile duct with special reference to late complications after total excisional operation.

The surgical treatment of 100 cases with congenital dilatation of bile duct with special reference to late complications was analyzed. There were no deaths nor occurrences of malignancy. Among 91 patients who had undergone the standard operation, namely total excision of the dilated extrahepatic bile duct and reconstruction after Roux-en-Y hepaticojejunostomy, there were one early complication (pancreatic juice leakage) and five late complications (four intrahepatic gallstones and one liver abscess). The cause of intrahepatic gallstone formation after a total excisional operation was attributed to the remaining intrahepatic bile duct dilatation and the stenosis located between the intrahepatic bile duct dilatation and the common hepatic duct. Accordingly, these results support the total excisional procedure for this condition; however, with regard to the cases associated with cystic dilatation of intrahepatic bile ducts, completely free bile drainage from the dilated intrahepatic biliary system should be performed at the radical operation.

Adolescent↗

PubMed1990

Long-term follow-up after surgery for patients with biliary atresia.

Long-term results after surgery for biliary atresia (BA) in 48 patients, ranging in age from 10 to 33 years, were examined. There were 19 males and 29 females. Twelve had correctable type BA and 36 had the noncorrectable type. Forty-one cases had no jaundice; seven did. Thirty-seven of the 48 cases were leading normal lives. Among them, six cases were enjoying their lives after overcoming sequelae, such as portal hypertension. The main morbidities of the remaining 11 long-term survivors were jaundice and portal hypertension. The growth of most cases were comparable to those of the normal Japanese population. The data of liver function tests were variable and disclosed a moderate degree of abnormality in patients mainly complicated by cholangitis. Eleven cases, including six jaundice cases, required treatment for esophageal varices and/or hypersplenism. In conclusion, the cured states of most cases without jaundice are satisfactory and these former patients have achieved a favorable quality of life. Early operations are essential to obtain good short-term results as well as good long-term results.

Adolescent↗

PubMed1990

Two-point rectal mucosal biopsy for selection of surgical treatment of Hirschsprung's disease.

A two-point rectal mucosal biopsy (utilizing a histochemical study), namely biopsies at sites 5 to 10 mm and 30 to 50 mm oral to the dentate line, was developed to differentiate patients who can be treated adequately by rectal myectomy without colostomy and those who require other definitive surgery for Hirschsprung's disease. The examinations were performed in 28 patients suspected having a short aganglionic rectum. Ganglion cells were demonstrated by upper biopsy in four of 13 neonates, six of nine infants, and three of six children. These cases were successfully treated by rectal myectomy. The two-point rectal mucosal biopsy is useful not only for making definitive diagnosis but also for the selection of the surgical treatment for patients with Hirschsprung's disease.

Biopsy↗

PubMed1990

Voluntary control of saccadic eye movements in patients with schizophrenic and affective disorders.

We have examined visually guided saccade and antisaccade tasks in 32 schizophrenics, 13 patients with affective disorders and 36 normal controls. Latencies of saccades were within the normal range in all patients examined. In the antisaccade task, 26/32 schizophrenics showed more errors and/or longer latencies, whereas 11/13 patients with affective disorders showed normal results. One manic patient showed significantly longer latency, and one bipolar patient showed a borderline error rate (15%). These results indicate that the antisaccade abnormalities in schizophrenics were not correlated with age, duration of illness, length of education or quantities of medication. None of the schizophrenics with normal antisaccades showed abnormalities in CT scans, while 73% of the schizophrenics who showed both higher error rate and longer latencies showed atrophy of the frontal cortex. The scores of conceptual disorganization and motor retardation in Brief Psychiatric Rating Scale (BPRS) were significantly higher in schizophrenics with abnormal antisaccades, while acute symptoms such as delusions and hallucinations were not correlated with the abnormalities.

Adolescent↗

PubMed1990

Mechanisms for muscarinic inhibition of somatostatin release from canine fundic D cells.

We undertook the present studies to explore the mechanisms by which carbachol inhibits the release of somatostatin-like immunoreactivity (SLI) from D cells. D cells were isolated from canine fundic mucosa by collagenase/EDTA dispersion followed by counterflow elutriation. Carbachol inhibited the release of SLI induced by forskolin, dibutyryl 3':5' cyclic adenosine monophosphate (cAMP), pentagastrin (PG), and 12-0-tetradecanoyl-phorbol-13-acetate in a fashion that could be prevented by pertussis toxin (PT) pretreatment of the D cells. Pertussis toxin also prevented the carbachol-induced inhibition of forskolin-stimulated cAMP generation and PG-stimulated [Ca2+]i mobilization. These data indicate that pertussis toxin sensitive inhibitory guanine nucleotide binding proteins mediate many of carbachol's inhibitory actions on D cells.

Animals↗

PubMed1990

Cellular mechanisms of somatostatin action in the gut.

We have used isolated canine parietal cells to examine the receptor and postreceptor events mediating the inhibitory effects of somatostatin on acid secretion. Somatostatin-14 (S14) and somatostatin-28 (S28) dose dependently inhibited parietal cells stimulated by secretagogues that activate both the adenylate cyclase/cyclic adenosine monophosphate and the inositol phospholipid/protein kinase C cascades. The inhibitory action was mediated via a specific cell surface receptor that consists of a single subunit protein (molecular weight 99,000 d). This receptor recognized S14 and S28 equally well. Somatostatin inhibited parietal cell activity via mechanisms that are both dependent on and independent of a pertussis toxin-sensitive inhibitory guanine nucleotide binding protein.

Animals↗

PubMed1990

Activation of PKC inhibits NaF-induced inositol phospholipid turnover in rat insulinoma cells.

An investigation was done to elucidate the regulatory role of protein kinase C (PKC) in insulin release and also the effects of PKC activation on NaF-induced inositol phospholipid (PI) turnover in and insulin release from rat insulinoma cells (RINr). NaF stimulated insulin secretion in association with an increase in [3H]inositol phosphate formation in RINr cells. Furthermore, NaF induced a rapid decrease in 32P-labeling of phosphatidylinositol-4,5-diphosphate (PIP2) with a concomitant increase of [32P]phosphatidic acid in prelabeled cells. In contrast, NaF had no effect on cyclic AMP production. Although phorbol 12,13-dibutyrate (PDBu) also stimulated insulin release, on concomitant administration of NaF and PDBu, insulin secretion was clearly less than that expected on the basis of an additive action. Moreover, PDBu significantly inhibited NaF-enhanced PI turnover. However, this inhibition was abolished after downregulating PKC by pretreating RINr cells with PDBu. Thus NaF-induced insulin release from RINr cells appears to involve enhancement of PI turnover. Moreover, because NaF is known to activate guanine nucleotide binding proteins (G proteins) directly, PKC activation appears to induce a mechanism that inhibits stimulus-secretion coupling at a level between G protein and phospholipase C-induced PIP2 hydrolysis.

1-Methyl-3-isobutylxanthine↗

PubMed1990

[Studies on FK482. II. Synthesis and structure-activity relationships of 7 beta-[(Z)-2-(2-aminothiazol-4-yl)-2-substituted acetamido]-3-vinyl-3-cephem-4-carboxylic acid derivatives].

Various 7 beta-[2-(2-aminothiazol-4-yl)-2-substituted acetamido]-3-vinyl-3-cephem-4-carboxylic acid derivatives (Ia--e, IIa--g) were synthesized in order to find a new orally active cephalosporin improving the antibacterial activity of cefixime (CFIX) against Staphylococcus aureus. These derivatives include three types of alpha-substituted 2-(2-aminothiazol-4-yl)acetyl side chain; i) mono or non substituted acetyl moiety, ii) carboxyalkoxyimino acetyl moiety, iii) phosphonomethoxyimino and hydroxyimino acetyl moiety. Their structure-activity relationships and urinary recoveries in rats were studied. As a result, the compound with a hydroxyimino acetyl side chain (IIg, FK482) showed good oral absorption and excellent antibacterial activity against both gram-positive and gram-negative bacteria and was selected as a candidate for clinical trial.

Animals↗

PubMed1990

Postoperative gastrointestinal hemorrhage in biliary atresia.

During the past 9 years, we have treated 23 patients with gastrointestinal hemorrhage following corrective surgery for biliary atresia. Ulcers or erosions of the stomach, duodenum or intestinal wall were observed endoscopically in 20 cases. In other 3 cases, bleeding point was not determined endoscopically, but massive bleeding was recognized frequently. Ten patients bled within 6 months of surgery, and the incidence of bleeding was also seen even after the age of 10 years. A history of cholangitis, the presence of jaundice and the use of cholagogues were related to the postoperative gastrointestinal bleeding. Serum concentrations of gastrin and gastric inhibitory polypeptide showed high values after surgery in almost half the biliary atresia patients examined, however, no clear relationship between the concentration of these factors and gastrointestinal hemorrhage was established.

Biliary Atresia↗

PubMed1990

Calcitonin gene-related peptide and induction of hyperglycemia in conscious rats in vivo.

The effect of calcitonin gene-related peptide (CGRP) on glucose metabolism was investigated in conscious and unrestrained rats in vivo. Intravenous injection of rat CGRP (5.67 and 0.567 nmol/kg) caused a significant, dose-dependent increase in plasma glucose concentration and a simultaneous dose-dependent increase in plasma insulin level. In contrast, plasma glucagon level was not changed. On the other hand, intravenous infusion of CGRP (46.6 pmol.kg-1.min-1) decreased tolerance to intragastric administration of glucose (IGGTT). Plasma insulin response to IGGTT, however, was not affected by CGRP infusion. Moreover, although intravenous injection of CGRP (5.67 nmol/kg) elicited a significant increase in plasma epinephrine and norepinephrine concentrations, concomitant administration of epinephrine and norepinephrine, inducing a more prominent rise in plasma catecholamines than those induced by CGRP, affected neither plasma glucose nor insulin levels. Finally, plasma insulin levels obtained by simulating CGRP-induced changes in plasma glucose or glucose plus catecholamine levels by infusion of glucose or glucose plus catecholamines were not different from those induced by CGRP injection. These results suggest that CGRP has a hyperglycemic action that is not mediated by sympathetic outflow in conscious rats, and inhibition of insulin secretion, if any, does not play a major role in this hyperglycemic action of CGRP. We have demonstrated specific CGRP receptors linked to adenylate cyclase activation in rat liver plasma membranes; this hyperglycemic effect of CGRP in vivo may be partly due to its direct action on the liver.

Animals↗

PubMed1990

Activation of adenylate cyclase by islet amyloid polypeptide with COOH-terminal amide via calcitonin gene-related peptide receptors on rat liver plasma membranes.

Both human and rat islet amyloid polypeptide with COOH-terminal amide (IAPP-NH2) dose-dependently displaced the specific binding of 125I-labeled [Tyr0] rat alpha-calcitonin gene-related peptide (CGRP) to rat liver plasma membranes, whereas human IAPP (IAPP-COOH) had no effect. Conversely, human or rat IAPP-NH2 but not human IAPP-COOH evoked dose-dependent activation of adenylate cyclase in the membranes, and these effects were significantly inhibited by the CGRP-receptor antagonist human CGRP-1(8-37). Moreover, the dose of human or rat IAPP-NH2 necessary for producing half-maximal activation of adenylate cyclase was comparable with that for producing a half-maximal inhibition of the label binding. Thus, IAPP-NH2 but not IAPP-COOH appears to induce adenylate cyclase activation via CGRP receptors on rat liver plasma membranes.

Adenylyl Cyclases↗

PubMed1990

[The clinical efficacy of outpatient extracorporeal shock wave lithotripsy].

From March 1989 through December 1989, 123 patients, 9 to 78 years old, were treated by extracorporeal shock wave lithotripsy (ESWL) with the Wolf Piezolith device. Outpatient treatment was performed routinely. Anesthesia was not required in all of the patients. No analgesia or sedation was given routinely. When pyuria had been found before treatment, a course of prophylactic oral antibiotics was given. Treatment consisted of 2000 to 6000 shocks in adults. The need for re-treatment was decided on the basis of the follow up X-rays. Fragmentation into particles 5 mm in size or less occurred in 144 of the 149 renoureteral units (96.6%). Unfragmented stones were treated successfully by the combination therapy of ESWL and fiberoptic transurethral nephroureterolithotripsy (f-TUL). Of 144 renoureteral units, 3-month follow-up data are available for 96. Among the 96 units, the rate of being free of stones was 67 per cent for renal stones and 96 per cent for ureteral stones treated in situ. The over-all rate of being free of stones was 80.2 per cent. There were no significant complications. Ultrasound imaging has proved to be as effective as X-ray imaging. Outpatient ESWL with the Wolf Piezolith device is considered to be safe and efficient for the initial treatment of urinary stones. On the other hand, ESWL monotherapy is not sufficient for the treatment of complete staghorn calculi or long-term impacted ureteral calculi. We think that the combination use of ESWL and f-TUL is the most effective procedure for treatment of complicated stones.

Adolescent↗

PubMed1990

[Ectopic production of human chorionic gonadotropin by poorly differentiated transitional cell carcinoma of the renal pelvis].

Herein we report a case of ectopic production of hCG by poorly differentiated transitional cell tumor of the renal pelvis. The patient was a 55-year-old male who had been diagnosed at another hospital as having giant hydronephrosis and renal stones and was referred to our hospital. The plain abdominal CT showed a low-density mass at the lower pole of the right kidney. His serum hCG level was as high as 120 mIU/ml. Transperitoneal nephrectomy was performed on July 7, 1987. Histopathological examinations showed the presence of squamous metaplasia within a high-grade transitional cell carcinoma, and immunohistochemical studies revealed the presence of chorionic gonadotropin in some giant cells. Two courses of combination chemotherapy with methotrexate, vinblastine, adriamycin and cisplatin (M-VAC regimen) were given to him from the third week after the operation. However, he died of debility with distant metastasis 6 months after the operation. As far as we know, this is the third reported case in Japan.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1990

[A case of isolated focal myositis successfully treated by arterial injection of prednisolone--its findings by CT scan and MRI].

A 25-year-old woman with a 2 years history of painful enlargement of the left calf visited our clinic because of ache in the left calf which became severe enough to interfere her walk. She had no history of trauma to the calf, and family history was negative for muscle disease. Physical examination showed an enlarged left calf muscle with pain which was evoked by stretching of the Achilles tendon. There was no muscle weakness or neurological abnormality. Laboratory tests were all within normal limits, including erythrocyte sedimentation rate and serum enzymes such as creatine kinase and aldolase. The CT scan revealed an isolated round-shaped low density area in the left calf muscle, which showed up as a markedly high signal intensity on T2 weighted images of MRI. The lesion was confirmed to be the lateral head of the gastrocnemius muscle. The specimen obtained from the affected muscle demonstrated degenerative and inflammatory changes together with excess fibrosis. There was no sarcoid lesion or malignancy. From the above results, the present case was thought to have isolated focal myositis. Prednisolone 80 mg (40 mg, twice, at 4-day intervals) was given to the left femoral artery without any trouble. Thereafter the patient became free from pain and difficulty in walking, and the lesion demonstrated by CT scan disappeared in 15 days. However, the high signal intensity on T2 weighted images faintly remained until the 54th day after the treatment. In summary, MRI is more sensitive than CT scan for detection of isolated focal myositis, which might be successfully treated by arterial injection of prednisolone within a short period than any other conventional methods.

Adult↗

PubMed1990

[Drug information in recent 5 volumes of the Year Book of Dentistry].

The Year Book of Dentistry appears annually, providing a review of dental articles. We surveyed the abstracts of the recent 5 volumes of the Year Book of Dentistry, from 1985 to 1989. Two hundred and eighty articles were abstracted in each volume, divided into about 13 categories. The proportion of abstracts concerned with drugs and drug therapies (here termed drug information) was almost 20% in all volumes. Most of the drug information appeared under the heading "Oral Medicine and Oral Pathology" (63%). The original articles for the abstracts were from many journals, but 70% of the drug information articles were from JADA, Oral Surgery, and 10 other journals. The classification of the drugs in the drug information were: drugs for dental treatment, antibacterials, antiinflammatories, hemostatics, anesthetics, and others. Oral manifestations of systemic diseases or side effects of drugs used for these diseases were also abstracted. There were numerous articles of systemic diseases, due to dental treatments, including infective, hematologic diseases.

Abstracting and Indexing↗

PubMed1990

[Clinico-pathologic evaluation of retroperitoneal lymph node metastasis in ovarian carcinoma].

Retroperitoneal lymph node dissection was performed in 18 cases of ovarian carcinoma. Of 18 patients, 8 (44.4%) patients had lymph node metastasis. It was found that 50.0% of patients with stage III and 100% of patients with stage IV had lymph node metastasis. Serous cystadenocarcinoma and poorly differentiated carcinoma were demonstrated to be the risk factors in lymph node metastasis. Lymph node metastasis was found to be significantly correlated with the volume of ascites, peritoneal cytology, or peritoneal dissemination. Patients without peritoneal dissemination or positive peritoneal cytology had no lymph node metastasis. Patients with bilateral ovarian tumors tended to have a higher incidence of lymph node metastasis than those with a unilateral ovarian tumor. The incidence of para-aortic lymph node metastasis was found to be higher than that of pelvic or inguinal lymph node metastasis. We concluded that in the clinical stage, serous cystadenocarcinoma, poorly differentiated epithelial carcinoma, ascites, peritoneal cytology, peritoneal dissemination and bilateral ovarian tumors were assumed to affect the incidence of retroperitoneal lymph node metastasis of ovarian carcinoma. It was suspected that the lymphatic spread of ovarian carcinoma had two routes: via ascites and peritoneal dissemination.

Ascitic Fluid↗