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Biomedical subjects

T Dohi

Publications and source records attributed to T Dohi.

At least 181 records · Page 10Linked to original sources
PubMed1978

Possible mechanisms of sustained tremor induction by nicotine in pilocarpine treated animals.

Alterations of steady state and metabolism of putative neurotransmitters were studied in the brain of rats with a sustained tremor evoked by nicotine and pilocarpine. The norepinephrine content in several brain regions was decreased whereas striatal dopamine was unchanged. Homovanillic acid concentrations were slightly increased, while 5-hydroxyindoleacetic acid concentrations were markedly increased. Pilocarpine alone increased the 5-hydroxytryptamine (5-HT) turnover rate at high ambient temperature (30-32 degrees C), but not at normal ambient temperature (22 +/- 2 degrees C), atropine partially blocked the increase of 5-HT turnover rate by pilocarpine. Pretreatment with p-chlorophenylalanine and hemicholinium-3 decreased the tremor intensity elicited by nicotine and pilocarpine . It is proposed that the increase of cholinergic function caused by nicotine and the activation of muscarinic receptors and the increase in 5-HT function caused by pilocarpine might be involved in the mechanisms of tremor induction by nicotine and pilocarpine.

Animals↗
PubMedDate not supplied

Three-dimensional medical imaging display with computer-generated integral photography.

A 3-D display system for medical imaging by computer-generated integral photography (IP) has been developed. Real 3-D images are generated from 3-D medical images and displayed by simple structure. Each point in 3-D space is reconstructed by the convergence of rays from many pixels on the computer display through the lens array. Only the coordinate of the best point is computed for each pixel on the display. The locations of images projected within 40mm from the display were found to be less than 2.0mm in error. Projected images could be observed with motion parallax within 10 degrees from the front of the display.

Algorithms↗
PubMedDate not supplied

Development of a tracking method for image analysis of time-lapse deformation of trabecular structure in a human bone.

A new method to track the deformation of the trabecular structure in a human bone, which determines the dynamic characteristics of bone, was developed using elastic matching. This is a kind of image analysis. By comparing two 3-D images of the same bone taken at different times, this method computes displacement of any points in the bone during the period. This method makes it possible to demonstrate the behavior of the trabecular structure to mechanical loads and to estimate changes in the strength of a bone.

Bone Diseases↗
PubMedDate not supplied

Immunohistological and biochemical detection of fucosylated polylactosamine antigen with monoclonal antibody ACFH18 in gastric cancer and normal gastric mucosa.

A mouse monoclonal antibody ACFH18, produced by immunizing with human gastric cell line MKN-74, recognizes a novel glycolipid antigen, fucosyl-lactoneodecaosylceramide. In the present study, we investigated the immunohistological localization of this antigen and its biochemical detection in glycolipid fraction in normal and malignant human gastric tissue, compared with other tumor-associated type-2 chain glycolipid antigens such as sialyl Lex, sialyl Lex-i and Ley. Reactivity with ACFH18 was detected immunohistologically in the proliferation zone of normal fundic gland region as well as in 38 of 54 cases of gastric cancer, with preferential binding to undifferentiated type cancer. Glycolipids reacting with ACFH18, especially slow-migrating glycolipids on thin-layer chromatography, were accumulated in all of four cancer specimens compared with normal mucosa obtained from the same patients. Many glycolipids with sialyl Lex or sialyl Lex-i epitope were detected in normal mucosa and almost all of these glycolipids were accumulated in cancer specimens. Sialyl LeX-i antigen was increased more specifically in cancer than sialyl LeX was. A Ley antigenic glycolipid was considerably decreased in three of four cancer cases and increased in one case. From these results, glycolipid detected by ACFH18 appeared to be a tumor-associated antigen comparable to sialyl LeX and sialyl Lex-i antigens, but with a unique character as an undifferentiated-type tumor-associated antigen.

Antibodies, Monoclonal↗
PubMedDate not supplied

Surgical treatment for non-dilated biliary tract with pancreaticobiliary maljunction should include excision of the extrahepatic bile duct.

BACKGROUND/AIMS: The authors evaluated the surgical treatment for non-dilated biliary tract with pancreaticobiliary maljunction. METHODOLOGY: Sixty-nine patients with pancreaticobiliary maljunction were divided into 61 patients with the dilated biliary tract and 8 with the non-dilated biliary tract. The levels of amylase activity in the bile in the gallbladder and the bile duct, the incidence and severity of postoperative cholangitis, and cell proliferating activity of the biliary tract epithelium, examined the proliferating cell nuclear antigen labeling index (PCNALI), were examined. RESULTS: Of the 61 dilated type patients, 12 were of Ia, 1 was of Ib, 22 were of Ic, 25 were of IV-A, and 1 was of IV-B according to Todani's classification. Cancer was detected in 7 dilated type patients and in 3 non-dilated type patients. A high level of amylase activity was measured in the bile juice in both the gallbladder and bile duct in all of the patients with pancreaticobiliary maljunction. PCNALI of the biliary tract epithelium of the patients without cancer (dilated type: bile duct 11.4%, gallbladder 12.7%; non-dilated type: bile duct 5.9%, gallbladder 13.8%) was higher than that of the patients without pancreaticobiliary maljunction (bile duct 1.5%, gallbladder 1.4%). CONCLUSIONS: In a non-dilated type, as well as in a dilated type, a high level of amylase activity and increase of cell proliferative activity of the biliary tract epithelium were observed. Therefore, these results suggest that the extrahepatic bile duct should be prophylactically removed in patients with non-dilated type as well as in those with dilated type pancreaticobiliary maljunction.

Amylases↗
PubMedDate not supplied

Measurement of peritoneal dialysate volume by CT.

Three-dimensional (3-D) graphic reconstruction of serial image data of x-ray CT on three dialysis patients was studied to measure peritoneal dialysate (PD) volume. Volume estimation with a surface reconstructed model provided a 16% error; a 35% error was found with a voxel model, although the total time required by the voxel model was 15 times less.

Aged↗
PubMedDate not supplied

Detailed characterization of reactivities of anti-gastric cancer monoclonal antibodies to carbohydrate antigen.

Four murine monoclonal antibodies (MoAbs), KM191, KM206, KM230 and KM231, raised against gastric cancer exhibited very similar reactivities to human carcinoma cells, whereas their abilities in probing the antigen shed from the cancer cells were quite different. We found in this study that the four MoAbs reacted immunologically with the same monosialo gangliosides derived from a gastric cancer cell line by two-dimensional high performance thin-layer chromatography. When the reactivities of the MoAbs to a number of purified gangliosides or oligosaccharides were examined, the carbohydrate structure of the antigen was determined as sialyl Lea. KM231 exhibited the highest binding avidity to the oligosaccharide and the ganglioside among the four MoAbs. In a comparative study of KM231 and NS19-9, which is a widely used sialyl Lea-reactive MoAb, KM231 bound to the oligosaccharide with higher affinity and detected the antigen in tissue sections with higher sensitivity. In addition, KM231 could detect a small amount of the antigen ganglioside in human gastric normal and cancerous mucosa and in gastric cancer cell lines by HPTLC-immunostaining.

Animals↗
PubMedDate not supplied

Benzodiazepines facilitate the stimulatory action of gamma-aminobutyric acid (GABA) on basal and veratridine-evoked catecholamine release from cultured bovine adrenal chromaffin cells.

Effects of benzodiazepines were investigated on the gamma-aminobutyric acid-induced modulation of the basal and veratridine-evoked catecholamine release from cultured bovine adrenal chromaffin cells. GABA by itself, caused catecholamine release and facilitated veratridine-evoked catecholamine release. Midazolam enhanced the GABA-evoked catecholamine release in a dose-related fashion and further facilitated the enhancement by GABA of the veratridine-evoked catecholamine release. Clonazepam, a selective central-type benzodiazepine receptor agonist, also enhanced the GABA-induced catecholamine release, whereas ethyl-beta-carboline-3-carboxylate, an inverse agonist of the benzodiazepine receptor, reduced the GABA-evoked catecholamine release. The dose-response curve of the GABA-evoked catecholamine release was shifted to the left by midazolam without affecting the maximal response to GABA. Facilitation by midazolam and clonazepam of the GABA action or inhibition by ethyl-beta-carboline-3-carboxylate was antagonized by RO15-1788, which by itself had no effect on the basal or GABA- and veratridine-evoked catecholamine release. These results suggest that the central-type benzodiazepine receptor participates in the GABAergic modulation of the catecholamine release from adrenal chromaffin cells.

Adrenal Glands↗
PubMedDate not supplied

Expanded selection criterion for Fontan's operation based on the size of distal pulmonary arteries.

This study examined pulmonary arterial size to clarify a quantitative selection criterion for Fontan's operation in six cases without pulmonary hypertension. Pulmonary arterial size was angiographically assessed before and after the operation. No enlargement of the artery was observed, even after the procedure, confirming the importance of preoperative pulmonary arterial size. All three cases with preoperative PAa/N-RPAa of more than 0.5 survived the operation, whereas two of the remaining three cases (less than 0.5) died due to low cardiac output. The only survivor in the latter group had previously received Glenn's anastomosis. Hemodynamic study was done simultaneously, and a significant exponential correlation was obtained between preoperative PAa/N-RPAa and perioperative post-repair right atrial pressure (p less than 0.025). It was concluded that the selection criterion based on pulmonary arterial size could be expanded to a PAa/N-RPAa value of 0.5 when no Glenn's anastomosis had previously been done and the rudimentary right ventricle was not to be utilized. The exponential curve is useful for postoperative care in Fontan's operation, since it indicates the central venous pressure necessary to sustain the circulation at a level corresponding to the preoperative pulmonary arterial size.

Blood Vessel Prosthesis↗
PubMedDate not supplied

Reactivity of a mouse/human chimeric anti-GM2 antibody KM966 with brain tumors.

With the aim of investigating the passive immunotherapy of brain tumors, we examined the binding of a mouse/human chimeric anti-ganglioside GM2 antibody KM966 to various organs and brain tumors. Frozen sections of 51 surgically resected brain tumors were stained with antibody KM966. Fourteen gliomas out of 16 were stained positively with antibody KM966. Eleven positive sections demonstrated homogenous staining. No specific binding to normal gray matter and white matter was observed. Some cases of meningiomas, neurinomas and metastatic brain tumors were stained with KM966 but with less frequency and intensity than gliomas. In addition, KM966 demonstrated strong antibody-dependent cellular cytotoxicity against human malignant glioma cells. These results showed that antibody KM966 will be useful for passive immunotherapy of malignant gliomas.

Adult↗
PubMedDate not supplied

Adrenal catecholamine secretory responses in young and adult dogs.

To elucidate the secretory sensitivity of the adrenal medulla in young animals, a comparative study of the adrenal secretory reactivity in young and adult dogs was made. In the isolated perfused adrenal gland, acetylcholine, nicotine, muscarine (10(-6)-10(-4) M) and high K+ (15-45 mM) enhanced catecholamine release. The release of catecholamines, expressed per weight of adrenal gland and caused by cholinergic secretagogues, was significantly higher in young dogs than in adult dogs. The proportion of noradrenaline to adrenaline plus noradrenaline in the tissue was higher in young dogs. The proportion of noradrenaline in the effluent was higher by increasing the concentrations of the stimulants, up to a similar level of the tissue noradrenaline/noradrenaline+adrenaline ratio. In in vivo studies, the increase in catecholamine concentration, especially of noradrenaline, in the plasma of femoral arteries, induced by intravenous injection of nicotine, was higher in young dogs than in adult dogs. We also measured the catecholamine-synthesizing enzymes activities in the adrenal medulla. Tyrosine hydroxylase and phenylethanolamine-N-methyltransferase activities were lower in young dogs, but there was no difference in dopamine-beta-hydroxylase activity between young and adult dogs. These results may suggest that young dogs are more sensitive to cholinergic stimulation in spite of their low catecholamine-synthesizing enzyme activity.

Adrenal Medulla↗