Search PubMed⌕ Search

Biomedical subjects

Y Hashimoto

Publications and source records attributed to Y Hashimoto.

At least 1,171 records · Page 65Linked to original sources
PubMed1989

An immunohistochemical study on the embryonic development of renin-containing cells in the mouse and pig.

The prenatal occurrence and distribution of renin-containing (RC) cells were investigated immunohistochemically in mouse and pig embryos. The RC cells of the mouse embryo were first observed at the 13th day of gestation at the walls of the renal, the mesonephric, the adrenal, the abdominal arteries, the adrenal glands and the testis. As the gestation of the mouse progressed, the RC cells had a tendency to localize in areas of the vascular pole of the metanephric glomerulus. In pig, when CRL was 0.8-2.0 cm, RC cells first appeared at the ventral walls of the dorsal aorta, the omphalo-mesenteric (i.e., the cranial mesenteric), the mesonephric, the mesonephric afferent glomerular arteries/arterioles and the inside of the mesonephric glomerulus. As the length of the pig embryo increased, no renin-immunoreactivity could be demonstrated at the degenerated mesonephros, while in the metanephros marked immunoreactivities were found only at the terminal regions of intralobular arteries, i.e., afferent arterioles or the vascular pole of the glomerulus.

Animals↗
PubMed1989

Pharmacokinetics and dromotropic activity of ajmaline in rats with hyperthyroidism.

1. The pharmacokinetics and the dromotropic action (increased PQ interval) of intravenously administered ajmaline (2 mg kg-1) were studied in hyperthyroid rats with sinus tachycardia. The hyperthyroidism was induced by intraperitoneal injection of 3,5,3'-triiodo-L-thyronine (0.5 mg kg-1) for 4 days. 2. The change in the ajmaline concentration in whole blood could be described by a biexponential equation. The steady state distribution volume of ajmaline decreased from 4.81 l kg-1 in control rats to 3.80 l kg-1 in hyperthyroid rats and the total body blood clearance was slightly higher in hyperthyroid rats than in control rats. 3. Ajmaline exhibited a saturable binding to rat plasma proteins, and one kind of binding site was found in the observed range of concentrations. The binding capacity was 2 fold higher in hyperthyroid rats than in control rats. 4. On the basis of the plasma unbound concentration, ajmaline exhibited an increased negative dromotropic activity in hyperthyroid rats compared with control rats. 5. A positive correlation was found between the pacing rate and the dromotropic action of ajmaline on atrioventricular conduction in isolated perfused hearts. There was no significant difference in the rate-dependence of the effect of ajmaline on the heart between control and hyperthyroid rats. 6. Our findings suggest that the increased dromotropic activity of ajmaline is mainly due to the increased heart rate in hyperthyroid rats.

Ajmaline↗
PubMed1989

Thrombus imaging with an I-123-labeled F(ab')2 fragment of an anti-human fibrin monoclonal antibody in a rabbit model.

The murine monoclonal antibody MA-15C5 binds to cross-linked fibrin but not to fibrinogen. Fab or F(ab')2 fragments of MA-15C5, labeled with iodine-123, were injected intravenously into nine rabbits with a nonocclusive 0.2-mL human plasma clot in the jugular vein and into eight control rabbits. Scintigrams obtained at hourly intervals after injection of the F(ab')2 fragment revealed a significantly higher accumulation of tracer in the clot region than in the contralateral region. The relative excess of tracer in the jugular vein region was significantly greater in the study animals than in the control animals throughout the study period. Blind reading of serial scans revealed no visible tracer accumulation in seven of eight control rabbits, whereas the scans of seven of nine study rabbits showed clearly visible accumulation (sensitivity = 77%, specificity = 87%). The Fab fragment of MA-15C5 had a lower affinity and bound less avidly to the blood clot in vivo. These results suggest that the F(ab')2 fragment has better imaging properties than the Fab fragment and that it may be useful for imaging blood clots in man.

Animals↗
PubMed1989

Effect of cyclophosphamide pretreatment on defective delayed-type hypersensitivity in autoimmune-prone MRL mice.

Autoimmune MRL mice develop a poor delayed-type hypersensitivity (DTH) after BCG cell wall (BCG CW) immunization. To test the possible participation of suppressor cells on DTH induction, MRL/MpJ-lpr/lpr (MRL-lpr) and MRL/MpJ-+/+ (MRL-+/+) mice were pretreated with cyclophosphamide (Cy) 4 days before the immunization. The footpad reaction to the purified protein derivative of tuberculin (PPD) was enhanced remarkably by Cy pretreatment in both MRL-lpr and MRL-+/+ mice. In addition, the lymph node cells obtained from nonpretreated MRL-lpr and MRL-+/+ mice at 7 days after BCG CW immunization suppressed the DTH induction of Cy-pretreated MRL-+/+ mice. On the other hand, a positive proliferative response to PPD in vitro was seen only in the cells from Cy-pretreated MRL-+/+ and younger MRL-lpr mice, but not in the cells of nonpretreated MRL-+/+ or both pretreated and nonpretreated older MRL-lpr mice. Removal of B220-positive cells from the lymph node cell populations of Cy-pretreated MRL-lpr mice restored PPD responsiveness, but the same treatment had no effect on the cells from nonpretreated MRL-lpr mice. The results suggest that DTH responses to PPD in MRL mice immunized with BCG CW are regulated by Cy-sensitive suppressor cells. These suppressor cells occur in MRL mice irrespective of whether they carry the lpr gene. And it is also demonstrated that MRL-lpr mice have TDTH precursor cells in a sufficient number for TDTH production even after expressing lymphadenopathy.

Animals↗
PubMed1989

Accessory cell function of human vascular endothelial cells in pokeweed-mitogen-stimulated immunoglobulin production by peripheral blood lymphocytes.

The possibility that human vascular endothelial cells (EC) can function as accessory cells for pokeweed mitogen (PWM)-induced immunoglobulin synthesis by peripheral blood lymphocytes was examined. Adherent cells (AC) were vigorously depleted from peripheral blood mononuclear cells (PBMC) and PBMC were cocultured with or without various numbers of EC or AC in the presence of PWM. EC which had been treated with interferon-gamma (IFN-gamma) expressed HLA class II antigens on the surface and promoted both IgM and IgG production by lymphocytes as effectively as monocytes did. Nontreated EC also enhanced immunoglobulin synthesis, but less effectively. Pretreatment of EC with monoclonal anti-HLA class II antigen antibody suppressed the accessory cell function of EC. These results indicate that EC have the ability to function as sufficient accessory cells in the mitogen-induced in vitro immunoglobulin synthesis, and that this ability was closely related to the expression of HLA class II antigen. Under the circumstance of an inflammatory response where IFN-gamma would exist, the accessory cell function of EC would be enhanced and would modify the immune response of immunocompetent cells.

Antigen-Presenting Cells↗
PubMed1989

Progressing ischemic stroke in a homozygote with variant antithrombin III.

A 31-year-old woman developed disturbance of consciousness and left hemiparesis. Cerebral computed tomograms showed a low-density area in the right temporal lobe that extended to the right parietal and left frontal lobes as her clinical symptoms worsened. The diagnosis of familial variant of antithrombin III (AT-III) was based on decreased biologic activity and a normal immunologic level of AT-III in this patient and in her family members. Transfusion of normal AT-III concentrate led to a striking clinical recovery. Blood coagulation studies revealed that nine of 13 family members had decreased biologic AT-III activity and that the patient herself was the only homozygote with variant AT-III. We conclude that variant AT-III, especially in a homozygote, seems to be one cause of ischemic stroke in young adults and that simultaneous measurement of both the biologic and immunologic activities of AT-III is necessary to detect it.

Adult↗
PubMed1989

Granulocytopenia and thrombocytopenia associated with combination therapy of amphotericin B and low-dose flucytosine in a patient with cryptococcal meningitis.

A patient was admitted complaining of fever and headache. He was suspected of meningitis due to nuchal rigidity, and a lumbar puncture was performed. The patient was diagnosed as having cryptococcal meningitis, as Cryptococcus neoformans was found in an India ink preparation of the cerebrospinal fluid. Both amphotericin B and low-dose flucytosine (50 mg/kg/d) were concomitantly administered to the patient and his clinical symptoms improved. However, the combination therapy induced granulocytopenia and thrombocytopenia, which resolved after discontinuance of the drugs. Amphotericin B alone failed to cause granulocytopenia or thrombocytopenia. These results suggest that the mechanisms of granulocytopenia and thrombocytopenia may be toxic reactions to flucytosine in the azotemic state caused by amphotericin B. Our report emphasizes the need for clinicians to monitor for granulocytopenia and thrombocytopenia in patients receiving treatment with both amphotericin B and flucytosine, even when flucytosine is administered in a low dose.

Adult↗
PubMed1989

The retinoic acid receptors alpha and beta are expressed in the human promyelocytic leukemia cell line HL-60.

The human promyelocytic leukemia cell line HL-60 can be induced to differentiate into granulocytes upon exposure to retinoids. Previously we have shown that extracts of undifferentiated HL-60 cells possess a specific retinoid-binding activity (RSBP-1) corresponding to an approximate 95 kilodalton (kDa) protein as determined by size-exclusion chromatography. We now extend these observations to reveal a second approximate 95 kDa retinoic acid-binding component (RSBP-2), which is separable from RSBP-1 using anion exchange chromatography. We further show that the chromatographic properties of RSBP-1 and RSBP-2 are identical to those found for the retinoid-binding activities present in extracts of HeLa cells transfected with the human retinoic acid receptor (RAR) expression vectors RAR-beta phi and RAR-alpha phi, respectively. Moreover, an antiserum preparation directed against RAR-beta selectively immunoprecipitated both the retinoid-binding activity in extracts of HeLa cells transfected with RAR-beta phi and that corresponding to RSBP-1 in HL-60 cell extracts. Similarly, an antiserum preparation directed against RAR-alpha immunoprecipitated the retinoid-binding activity in extracts from RAR-alpha phi transfected HeLa cell as well as that corresponding to RSBP-2 in HL-60 cell extracts. Using these antisera, Western blot analyses of extracts from HL-60 cells, and from HeLa cells transfected with either RAR-alpha phi or RAR-beta phi, confirmed that RSBP-2 and RSBP-1 are identical to RAR-alpha and RAR-beta, respectively. However, RAR-alpha, RAR-beta, RSBP-1, and RSBP-2 appeared as an approximate 51 kDa species in sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis in contrast with an apparent approximate 95 k mol wt as estimated from size-exclusion chromatography in the presence of 0.6 M KCl.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies↗
PubMed1989

Synthesis and biological evaluation of 3-chloro-1-carbacephem compounds.

The 3-chloro-1-carbacephem nucleus was prepared for the first time from a 3H-1-carbacephem compound through a sequence of reactions involving addition of thiophenol, oxidation of sulfide to sulfoxide, and alpha-chlorination of the sulfoxide, followed by elimination of phenylsulfinic acid. The 2-beta-methyl analog was similarly prepared, but the 2 alpha-methyl analog was not obtained. Optical resolution of the 3-chloro-1-carbacephem compound was achieved by the employment of penicillin acylase. That is, the 7-phenylacetamido derivative was enantioselectively hydrolyzed to afford the optically active 7-amino-3-chloro-1-carbacephem compound. Carbacefaclor, the carbacephem analog of cefaclor, was directly and efficiently prepared by enzymatic phenylglycylation of the racemic 7-amino-3-chloro-1-carbacephem compound by using immobilized penicillin acylase. Carbacefaclor thus prepared exhibited comparable antibacterial activity against most gram positive bacteria tested and higher activity against typical gram negative bacteria as compared with cefaclor. Moreover, carbacefaclor possessed remarkably high chemical stability.

Cephalosporins↗
PubMed1989

Synthesis and biological evaluation of optically active 3-H-1-carbacephem compounds.

3-H-1-Carbacephem nuclei with or without a 2 alpha- or 2 beta-methyl group were prepared via 2 + 2 cycloaddition followed by intramolecular Horner-Emmons cyclization. Optically active 3-H-1-carbacephem compounds were efficiently prepared by employing a penicillin acylase-producing microorganism in two ways. That is, the 7-phenylacetamide of a racemic carbacephem nucleus was hydrolyzed enantioselectively with the enzyme to afford the optically pure nucleus, which was then acylated to give antimicrobial compounds. Alternatively, a racemic carbacephem nucleus was directly and enantioselectively phenylglycylated with the enzyme. 3-H-1-Carbacephem nuclei appeared to be better substrates for penicillin acylase than penam or cephem nuclei of natural origin. 3-H-1-Carbacephem compounds showed potent antimicrobial activity; compound 32a exhibited activity comparable to that of ceftizoxime, a cephem analog with the same acyl group. It is of interest that the 3-H-1-carbacephem compound turned out to have more potent antimicrobial activity than its 3-substituted methyl analog.

Bacteria↗
PubMed1989

Morphology of blood cells in carp (Cyprinus carpio L.).

The morphology of blood cells in the carp was investigated by light and electron microscopy. Erythrocytes, thrombocytes, lymphocytes, granulocytes and monocytes were identified as the peripheral blood cells. Thrombocytes were round to long oval, each containing vesicular and microtubular structures and an oval nucleus with abundant heterochromatins. Lymphocytes were divided into three types in size, small, medium and large. Some of the small and medium lymphocytes were alpha-naphthyl-acetate esterase (ANAE) positive, while large lymphocytes were pyroninophilic. Granulocytes were distinguished into three types (type I, type II and type III) according to the morphology of the nucleus and granules. Type I granulocytes possessed lobulated nuclei and a large number of cytoplasmic granules, each of which was oval and contained electron-dense materials and a crystalloid. Type II granulocytes had small eccentric nuclei and were subdivided into IIa and IIb granulocytes by electron microscopic analysis. Granules of type IIa granulocytes were furnished with an electron-dense rim. Granules of type IIb granulocytes were larger than those of type IIa, containing randomly distributed electron-dense and electron-lucent materials. Type III granulocytes possessed round nuclei and a few large granules. The granules were filled with regularly arranged fibriform materials and some needle-like structures. Monocytes were morphologically similar to those of mammals.

Animals↗
PubMed1989

Effects of ligation of the ductus deferens on the fowl epididymal region.

The effects of ligation of the ductus deferens on the epididymis in the fowl were studied histochemically and immunohistochemically to reveal the mechanisms of sperm disposal. At one week post-ligation, the lumina of the rete testes (RT) and the efferent ductules (ED) were distended and filled with densely accumulated spermatozoa. Macrophages and foreign-body giant cells were aggregated in and around the accumulations. The epithelium regressed in the initial portion of the RT with the invasion of fibroblasts and heterophiles into the lumen. The other part of the epithelium was penetrated by many spermatozoa. Numerous lymphocytes and plasma cells infiltrated into the interstitium. At 4 weeks, larger number of spermatozoa agglutinated in the lumen, and large masses of foamy cells and proliferated connective tissue protruded into the lumen. At 8 weeks, large masses of foamy cells were noted. The connecting ductules or the epididymal duct showed no marked changes after ligation. The epithelium of the ED showed weaker or no acid phosphatase activity after ligation. Immunoglobulin G-containing cells increased in number in the interstitium. These results showed that ligation of the ductus deferens in the fowl causes granuloma in the RT and ED, and that epithelial cells, macrophages and granuloma are engaged in the removal of spermatozoa. The participation of antibody is suggested in the sperm disposal processes.

Animals↗
PubMed1989

Scirrhous carcinoma cell invasion into the stomach wall detected by monoclonal antibody S202: a comparison between immunoperoxidase and hematoxylin-eosin stain.

We used anti-scirrhous carcinoma monoclonal antibody (MAb) S202, which reacted strongly with scirrhous gastric cancer, to evaluate the depth of cancer cell invasion into the stomach wall. Sixty-eight scirrhous gastric cancer specimens were stained with the avidin-biotin peroxidase complex method using MAb S202. There were some discrepancies between the histological evaluation of the immunoperoxidase (IP) and hematoxylin-eosin (HE) staining regarding the depth of tumor invasion. In two of the 14 HE staining cases in which carcinoma had extended as far as the proper muscular layer, IP staining revealed that the lesions had actually penetrated this layer. As well, in two of the 18 HE staining cases in which carcinoma cells had not penetrated as far as the serosa, IP staining revealed that they had, in fact, reached the serosal surface. The invasive carcinoma cells were more easily discerned using IP staining with MAb S202 rather than using histological staining with HE. Thus, MAb S202 may be useful for precise identification of carcinoma cells.

Adenocarcinoma, Scirrhous↗
PubMed1989

A microtestplate-immunofluorescence assay for anti-Trypanosoma cruzi antibodies.

A new microassay method for the detection of anti-Trypanosoma (T.) antibodies was developed by using Terasaki's microtestplates, and T. cruzi or other parasites were immunofluorescently labeled with polyclonal or monoclonal anti-T. cruzi antibodies. The fluorescence intensity of immunofluorescently stained parasites was assessed by either visual observation or quantitative analysis using a microscopic spectrophotometer. Although the sensitivity of the microtestplate assay was nearly equal to that of the conventional glass slide assay or ELISA, this method is easier in the assay procedures and spares the amount of antibodies and the number of target parasites requisite to the assay.

Animals↗
PubMed1989

Production and characterization of monoclonal antibodies against Trypanosoma cruzi-associated antigens.

Nine monoclonal antibodies (mAb) recognizing characteristic antigens in Trypanosoma (T.) cruzi were obtained from hybridomas which had been established by a fusion between mouse myeloma cells and the spleen cells of a mouse immune to the epimastigote form of T. cruzi (Tulahuen strain). Antigen specificities of these mAb were assessed by an indirect immunofluorescence (IIF) method using T. cruzi in different life cycles (amastigote and trypomastigote) and other members of the Trypanosomatidae. The mAb were classified into 3 groups from their reaction patterns to different parasites: 1) The strain specific mAb that reacted only with T. cruzi Tulahuen epimastigote, 2) the species specific mAb that reacted with all T. cruzi strains but not with other species of parasites, and 3) the mAb that were cross-reactive with other species of Trypanosomatidae. Most mAb were specific to epimastigote form of T. cruzi, but some reacted weakly with trypomastigote and amastigote form of the parasites. Immunoblotting and glycolipid analyses of the membrane fraction of homogenized parasites using the mAb identified at least 3 distinct antigenic molecules; those of protein nature having Mr. 43,000 and 58,000 and Mr. 43,000 and 62,000 and molecule(s) of glycolipid nature.

Animals↗
PubMed1989

Neural mechanisms of chromatic adaptation in L-type cone horizontal cells of the carp retina.

When a background light is delivered, the responsiveness of horizontal cells to light stimulus initially lowers but subsequently recovers gradually as shown by the increase in response amplitude to test light. These changes of responsiveness are observed when white or close wavelengths are used for both the background and test lights. However, the response amplitude to blue-green test light was initially enhanced but decreased and reached a steady state after the onset of red background illumination. The mechanism causing such a change of test responses was studied in the luminosity-type cone horizontal cells. The initial response enhancement was accompanied by an increase of the slope of hyperpolarizing phase, while the subsequent decrease of response amplitude was caused by the advancement of the recovery phase. The advancement of the recovery phase was eliminated by gamma-aminobutyric acid (GABA) or Co2+ (50 microM), which blocks GABA-induced currents in cone terminals. Dopamine, which inhibits GABA release from horizontal cells, stimulated the advancement of the recovery phase. The time course of the hyperpolarizing phase was not affected by these agents. The enhancement and the subsequent decrease of test responses were also observed in 6-hydroxydopamine-treated retinae. The results suggest that the GABAergic feedback pathway from horizontal cells to cones advances the recovery phase of response to test light. It appears, therefore, that the feedback modifies the responsiveness of horizontal cells to light stimulus under a red background illumination. The mechanism enhancing response amplitude will be also discussed.

Adaptation, Physiological↗