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Biomedical subjects

T Amano

Publications and source records attributed to T Amano.

At least 289 records · Page 16Linked to original sources
PubMed1987

Comparative studies on the gastrointestinal lesions caused by several nonsteroidal anti-inflammatory agents in rats.

The gastrointestinal toxicity of a single oral administration of five nonsteroidal anti-inflammatory agents (NSAIDs) to rats was compared, by a method using 51Cr-labeled red blood cells (RBC), and by macroscopic and microscopic examination. From the profile of gastrointestinal bleeding, the NSAIDs could be divided into a group consisting of aspirin (ASA), oxaprozin (OXP) and 2-[4-(3-methyl-2-butenyl)phenyl]propionic acid (TA), which caused only a transient increase in fecal blood loss based on a gastric lesion, and another group including indomethacin (IM) and ibuprofen (IP), which produced a biphasic increase in the blood loss. The initial phase was caused not only by a gastric lesion but also an intestinal lesion, and the secondary phase originated only in the intestinal lesion. The order of potency causing blood loss was IM much greater than IP greater than ASA much greater than TA greater than OXP. The safety ratio of OXP and TA was shown to be more favorable than that of the other three drugs.

Administration, Oral↗
PubMed1987

Comparison between pial and intraparenchymal vascular responses to sympathetic stimulation under hypercapnic conditions. With special reference to the mechanism for escape phenomenon.

We have shown that secondary vasodilation ('escape' phenomenon) during sympathetic nerve stimulation occurs in the intraparenchymal vessels but not remarkable in the pial vessels. To test a possible role of CO2 accumulation in the brain tissue in this phenomenon, the responses of pial and intraparenchymal vessels to sympathetic nerve stimulation were investigated during hypercapnia in 9 cats by using a video camera photoelectric system. The ipsilateral superior cervical ganglion was electrically stimulated for 5 min during hypercapnia (PaCO2 = 50 +/- 2 mm Hg). The intraparenchymal vessels as well as pial vessels remained constricted throughout the stimulation. Secondary dilation of the intraparenchymal vessels as seen at the later stage of sympathetic stimulation during normocapnia was not observed under the hypercapnic conditions. We assume that the arterial CO2 tension was so high that the constriction of inflow vessels could not result in accumulation of CO2 in the brain parenchyma. The accumulation of chemical metabolites as represented by CO2 is therefore considered to be the most probable mechanism underlying the escape phenomenon of the intraparenchymal vessels.

Animals↗
PubMed1987

Dog erythrocyte rosette-forming lymphocyte: blockage by OKT11 monoclonal antibody.

Human peripheral blood mononuclear cells (PBM) were separated into sheep erythrocyte rosette-forming (Es+) and non Es+ cells by the Ficoll-Hypaque gradient sedimentation method. Thirty-eight percent of the Es+ cells formed rosettes with dog erythrocytes and were designated as Es+Ed+ cells. The remaining Es+ cells were designated as Es+Ed- cells. Only a few non Es+ cells formed rosettes with dog erythrocytes. Among Es+Ed+ cells, T4 antigen-positive cells were observed approximately 1.7 times as often as T8 antigen-positive cells, when measured by staining with OKT4 or OKT8 monoclonal antibody. Among Es+Ed- cells, however, T4 and T8 antigen-positive cells were observed in almost equal proportion. Preincubation of PBM with OKT11 monoclonal antibody, but not with OKT4 monoclonal antibody, inhibited the rosette formation with dog as well as sheep erythrocytes. These results indicated that Es+Ed+ cells were a subpopulation of T-cells in which a majority of the cells were T4 antigen-positive, and that the binding sites of dog erythrocytes on human T-cells was closely linked with that of sheep erythrocytes.

Animals↗
PubMed1987

[The effect of gastrectomy on serum 5-FU concentrations of patients administered UFT per os].

Ten post-total gastrectomy patients and five postsubtotal patients were administered with UFT 3 capsules per os. Then the concentrations of the serums FT-207, 5-FU and Uracil, and that of 5-FU in the lymph-nodes were measured chronologically. The concentration of serum FT-207 reached to its peak one hour after administration of the regimen for both the total and subtotal gastrectomy patients and gradually lowered. The 5-FU serum concentration, on the other hand, showed a rapid drop after reaching a peak one hour after administration of the UFT for both the post-total and subtotal gastrectomy patients. The concentration of 5-FU in the lymph nodes remained five times as high as the serum concentration after four hours for both the post-total and subtotal gastrectomy patients.

Adult↗
PubMed1987

[An in vitro chemosensitivity study using the human tumor clonogenic assay in urological malignancies: a preliminary report].

Surgical tumor specimens from 67 urological malignancy patients were subjected to a human tumor clonogenic assay (HTCA) developed by Hamberger and Salmon. Appreciable growth of colonies was obtained in 20 of the 33 renal cancers, 20 of the 30 urothelial cancers and 1 of the 4 testicular cancers examined. Using HTCA, a plating efficiency ranging from 0.01 to 0.5% was obtained in these urologic malignancies. However, colonial growth adequate for chemosensitivity was obtained in 30 of these 67 patients. According to Von Hoff's definition, more than a 70% decrease in the plating efficiency after anticancer drug exposure was defined as susceptible. Susceptibility to vinblastine (VBL) was seen in 4 of the 11 patients with renal cancer. Susceptibility to cis-dichlorodiamine platinum (CDDP) was seen in 4 of the 15 patients with urothelial cancer, 1 of the 4 patients with renal cancer, and that to adriamycin (ADM) was seen in 3 of the 15 patients with urothelial cancer, 2 of the 10 patients with renal cancer and 1 patient with testicular cancer. For comparison, the ratio of IC90 to the peak plasma concentration of the drug tested was used as the "in vivo-in vitro therapeutic index (TI)". According to TI, susceptibility to VBL was seen in 3 of the 7 patients with renal cancer, and that to CDDP was seen in 2 of the 12 patients with urothelial cancer, and 1 of the 2 patients with renal cancer. Susceptibility to ADM was seen in 3 of the 15 patients with urothelial cancer, and 1 of the 6 patients with renal cancer.(ABSTRACT TRUNCATED AT 250 WORDS)

Antineoplastic Agents↗
PubMed1986

Affinity purification of the opioid receptor in NG 108-15 cells using an avidin-biotin system with a novel elution method.

Affinity purification of the opioid receptor in NG 108-15 cells was carried out using an affinity resin based on the avidin-biotin interactions, but a new elution method was employed with a radioligand of sub-micromolar concentration. A synthesized biotinyl derivative of leucine-enkephalin has a high affinity for the delta-receptor, but the affinity was lowered 10-fold in the presence of avidin. The new elution method is based on this affinity decrease and resulted in a 100-fold purification over the initial crude materials in the single step. SDS-polyacrylamide gel electrophoresis of the purified receptor revealed three polypeptides of 58, 65 and 71 kDa as possible components of the delta-receptor.

Avidin↗
PubMed1986

Comparison between pial and intraparenchymal vascular responses to cervical sympathetic stimulation in cats. Part 1. Under normal resting conditions.

To investigate the role of sympathetic regulation in both resistance and capacitance vessels in cerebral circulation, the response of pial and intraparenchymal vessels to sympathetic nerve stimulation were simultaneously examined in 14 cats by means of a newly developed video camera photoelectric system. The system consisted of a video camera system for measurement of pial vascular diameters and a photoelectric apparatus for estimating regional cerebral blood volume in the intraparenchymal vessels. The ipsilateral superior cervical ganglion was electrically stimulated for 5 min. Initially, both the pial and intraparenchymal vessels constricted. The large pial arteries (173 +/- 25 micron, mean +/- SEM) remained constricted throughout the stimulation, whereas the intraparenchymal vessels began to dilate after the initial constriction and exceeded the control level at 175 +/- 25 s despite continued stimulation. In conclusion, such sympathetic nerve stimulation is considered to exert a constrictive effect on the intraparenchymal as well as the pial vessels at the early stage. The compensatory dilation of the intraparenchymal vessels was delayed 3 min after initiation of the stimulation.

Animals↗
PubMed1986

Monitoring of intracellular Ca2+ elevation in a single neural cell using a fluorescence microscope/video-camera system.

For monitoring the changes in intracellular free Ca2+ concentration ([Ca2+]i), we developed a simple system combining a fluorescence microscope, an image intensifier, a video-camera, a cathode ray tube display and a photodiode, employing quin2 as a Ca2+ indicator. We recorded increases of the fluorescence intensity due to [Ca2+]i rises, when high K+ medium, neurotransmitter and Ca2+ ionophore were applied to the single cells of nervous system origin in culture. The present system is capable of simultaneous detection of the [Ca2+]i changes from multiple separate cells.

Aminoquinolines↗
PubMed1986

Cytosolic calcium elevation and cGMP production induced by serotonin in a clonal cell of glial origin.

It has been shown recently that astroglial cells of the mammalian CNS possess receptors for neurotransmitters. In order to analyze what sequences of cellular events occur upon activation of these glial receptors, we utilized a 5-HT receptor in a rat clonal cell of glial origin as a model system. When the C6BU-1 glioma cells were exposed to 5-HT, the cytosolic Ca2+ concentration ([Ca2+]i) was elevated and the cellular content of cGMP was increased in a dose-dependent manner. 5-HT receptor antagonists and a Ca2+ entry blocker suppressed the increases in both [Ca2+]i and cGMP. The magnitude of the cGMP increment depended on the environmental Ca2+ concentration and was totally blocked by Ca2+ depletion. Application of a Ca2+ ionophore increased [Ca2+]i and cGMP. There was a tendency for extremely high [Ca2+]i to suppress the cGMP increment. On the contrary, membrane-permeable cyclic nucleotide analogs failed to increase [Ca2+]i. These results suggest that the following sequence of events occurs in 5-HT-induced C6BU-1 cells: activation of 5-HT receptors, Ca2+ influx, a rise in [Ca2+]i, activation of guanylate cyclase, and, finally, activation of cyclic nucleotide phosphodiesterase.

Animals↗
PubMed1986

[Clinical study of cefmenoxime in the field of abdominal surgery].

The effect of cefmenoxime (CMX) was evaluated in the abdominal surgery at 18 hospitals on the prevention and the treatment of postoperative infections. The results were summarized as follows. In 179 patients with prophylactic use of 2-4 g of CMX a day, no postoperative infection was observed in 94.4%. Using fever index to judge the effect of CMX in prevention of postoperative infections, the value of fever index was higher in the infected group than in the non-infected group. A significant difference was also observed in mean fever index value between the groups given CMX in 2 g and 4 g daily, being 15.4 degree hours and 1.7 degree hours. The incidence of postoperative infections was higher in cases with intraoperative bleeding of more than 500 ml than in cases with less bleeding. Postoperative infection and peritonitis subsided after the administration of 2-4 g of CMX/day for more than 8 days in 77.1% of cases. Very few side effects were noted due to CMX. These results suggest that CMX is safe and effective in the field of abdominal surgery for the prevention of postoperative infections and in the treatment of postoperative infections.

Abdomen↗