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Biomedical subjects

H Takagi

Publications and source records attributed to H Takagi.

At least 919 records · Page 51Linked to original sources
PubMed1989

Vagal afferents interact with substance P-immunoreactive structures in the nucleus of the tractus solitarius: immunoelectron microscopy combined with an anterograde degeneration study.

The morphological features of substance P-immunoreactive (SP-IR) structures in the nucleus of the tractus solitarius (NTS) were examined by immunoelectron microscopy combined with an anterograde degeneration study. Vagal afferents were allowed to degenerate by resecting the nodose ganglion two days prior to the examination. SP-IR axon terminals in the ipsilateral NTS were often found to make a synaptic contact with non-reactive dendrites in contact with degenerated terminals. SP-IR terminals also made contact with degenerated terminals, or SP-IR cells in contact with degenerated terminals. These findings suggest a close relationship between SP neuronal structures and vagal afferents in the NTS.

Afferent Pathways↗
PubMed1989

Neuropeptide Y afferents have synaptic interactions with histaminergic (histidine decarboxylase-immunoreactive) neurons in the rat brain.

The synaptic interaction was identified between histaminergic cells and neuropeptide Y (NPY)-immunoreactive axon terminals in the caudal magnocellular nucleus, by means of the immunoelectron microscopic mirror method. This observation suggests that NPY afferents exert monosynaptic influences upon the functioning of the central histaminergic neuronal system.

Afferent Pathways↗
PubMed1989

The coexistence of substance P- and glutamic acid decarboxylase-like immunoreactivity in entopeduncular neurons of the rat.

The coexistence of substance P- and glutamic acid decarboxylase-like immunoreactivity in cell bodies was investigated in the entopeduncular neurons of the rat by the double-immunofluorescence method using species-specific antibodies. Over half of the substance P-like immunoreactive cells were GABAergic. Double-labeled neurons were generally seen in the rostral to the middle region of the entopeduncular nucleus. Since the rostral portion of the entopeduncular nucleus mainly projects to the lateral habenular nucleus, it is suggested that double-labeled neurons in the entopeduncular nucleus largely project to the lateral habenular nucleus which is involved in the limbic system.

Animals↗
PubMed1989

A monoclonal antibody against COOH-terminal peptide of human liver manganese superoxide dismutase.

Three stable hybridoma cell lines producing monoclonal antibodies specific for human liver manganese superoxide dismutase were established, and one monoclonal antibody, PG 11, was chosen for immunochemical studies. Immunoblotting demonstrated that the monoclonal antibody binds exclusively to the manganese superoxide dismutase. Immunohistochemical studies indicated that the enzyme is localized in the matrix of human liver mitochondria. To localize antibody-binding epitope, synthetic peptides of the NH2-terminal (residues 1-16) and COOH-terminal (residues 182-189, 190-196, and 182-196) parts of the enzyme were synthesized, and then their effects on the binding were studied using an enzyme-linked immunosorbent assay method. All of the above COOH-terminal peptides inhibited the binding whereas the NH2-terminal ones did not, indicating that PG 11 recognizes several peptides of COOH termini of manganese superoxide dismutase. This is the first report of monoclonal antibodies against human manganese superoxide dismutase with a distinct epitope and of the immunocytochemical demonstration of manganese superoxide dismutase.

Animals↗
PubMed1989

The kyotorphin (tyrosine-arginine) receptor and a selective reconstitution with purified Gi, measured with GTPase and phospholipase C assays.

We attempted to identify the kyotorphin receptor and the post receptor mechanisms mediated by GTP-binding proteins (G-proteins), using reconstitution techniques. The specific binding of [3H]kyotorphin in rat brain membranes was composed of high affinity (Kd = 0.34 nM) and low affinity (Kd = 9.07 nM) binding. As the high affinity binding disappeared in the presence of guanosine 5'-O-(3-thiotriphosphate) and MgCl2, we investigated the kyotorphin receptor-mediated changes in membrane G-protein activity by measuring low Km GTPase activity. Kyotorphin produced a stimulation of low Km GTPase, and this stimulation was antagonized by Leu-Arg, a synthetic dipeptide which showed a potent displacement of [3H]kyotorphin binding, yet in itself had no effect on the low Km GTPase. The kyotorphin stimulation of low Km GTPase was abolished by pretreating membranes with islet-activating protein, pertussis toxin, and was recovered by reconstitution with purified G-protein, Gi, but not with Go. Similar evidence of selective coupling of kyotorphin receptor to Gi was obtained with the phospholipase C assay. Kyotorphin-induced stimulation of phospholipase C was also abolished by islet-activating protein-treatment and recovered by reconstitution with Gi but not with Go. These findings indicate that specific high and low affinity kyotorphin receptors exist in the rat brain and that the kyotorphin receptor is functionally coupled to stimulation of phospholipase C, through Gi. This study provides the first evidence of a selective involvement of Gi in the receptor-mediated activation of phospholipase C.

Animals↗
PubMed1989

Parvicellular adrenergic neurons receive substance P-ergic inputs in the nucleus of the tractus solitarius of the rat.

Synaptic interaction between parvicellular adrenergic neurons and substance P (SP) afferents in the caudal part of the nucleus of the tractus solitarius (NTS) was demonstrated by the immunoelectron microscopic mirror method, using antisera against phenylethanolamine N-methyltransferase (PNMT) and SP. SP-immunoreactive (SP-IR) terminals formed synaptic contacts with PNMT-IR neurons. It is suggested that SP afferents directly affect parvicellular adrenergic neurons via synapse in the NTS.

Adrenergic Fibers↗
PubMed1989

Expression of Lewisa, Lewisb, Lewisx, Lewisy, siayl-Lewisa, and sialyl-Lewisx blood group antigens in human gastric carcinoma and in normal gastric tissue.

A panel of 6 mouse monoclonal antibodies detecting blood group antigens of the Lewis systems and their sialylated derivatives have been used to define the immunoanatomic distribution of these antigenic structures within the normal human gastric mucosa and in gastric cancer tissues. The reagents employed detect the following blood group specificities: Lewisa, Lewisb, Lewisx, Lewisy, sialylated Lewisa, and sialylated Lewisx. We have analyzed the presence of these antigens in histologically normal gastric mucosa and in gastric carcinoma from 61 patients by the immunoperoxidase method. In addition, we simultaneously examined the blood group and secretor status in 31 of the 61 individuals studied. Immunohistochemical analysis revealed that these antigenic systems are differentially expressed in cell types and cell layers of the normal gastric epithelium. Major differences were observed in surface epithelia and in deep glands including Brenner's gland of the gastroduodenal junction, mainly in the pronounced expression of Lewisa and Lewisb antigens in the former and the expression of Lewisx and Lewisy in the latter. In secretor individuals, Lewisb was the dominant antigen in the surface epithelium, and in nonsecretors, Lewisa was observed in the surface epithelium, Lewisx and Lewisy were both detected in the deep glands and in Brenner's glands regardless of the secretor status. The expression of sialylated derivatives in normal gastric tissues was considerably reduced but was consistent with the expression of their precursors in normal gastric epithelium. In gastric cancers, more pronounced expression of Lewisa and sialylated Lewisa was observed in secretor individuals and acted as a tumor-associated antigen. Comparison of the plasma level of sialylated Lewisa and its tissue expression demonstrated that the shedding of the antigen into interstitial stroma correlated with the detection of the antigen in serum. These studies confirmed the importance of blood group antigens as normal differentiation antigens. Examination of secretor status clarified the mechanism of Lewisa and Lewisb antigen expression in gastric surface epithelium. Alterations in the expression of these antigens and an increase of sialylated derivatives in gastric cancers demonstrated that these blood group antigens are useful tools for the analysis of histogenesis and organogenesis in the stomach and its neoplastic and nonneoplastic diseases.

Antibodies, Monoclonal↗
PubMed1989

The influence of calcium phosphate ceramics and glass-ceramics on cultured cells and their surrounding media.

The cytotoxicity of hydroxyapatite (HA), tricalcium phosphate (TCP), and two types of apatite-containing glass-ceramics designated A.W-GC and A.W.CP-GC was evaluated by the direct contact method using V79 cells. Compatibility of the cells was assessed as a function of cellular attachment and subsequent growth using scanning electron microscopy. Although all of the tested materials have surfaces available for cellular attachment, cell growth was markedly inhibited by HA sintered at 600 degrees C and 900 degrees C, and slightly inhibited by HA sintered at 1200 degrees C, TCP and the glass-ceramics. In attempts to clarify the cause of this toxicity, the interactions of the ceramics with culture medium was assessed by measurement of calcium (Ca), inorganic phosphate (P), magnesium (Mg), pH and albumin content in the medium. The grade of toxicity corresponded to the degree of reduction of Ca, P, and albumin in the medium. Furthermore, surface reactions of the ceramics were demonstrated to vary in both mode and degree depending on their chemical structure and level of microporosity. Thus, the surface reactivity of ceramic materials should be always taken into account in discussing their biocompatibility in vivo.

Animals↗
PubMed1989

Application of the immunoperoxidase method for rapid intraoperative pathological diagnosis of pancreatic cancer.

Intrapancreatic extension of pancreatic duct cell carcinoma in 19 resectable cases was evaluated by both hematoxylin and eosin (H&E) staining and quick immunostaining using antibodies against cancer-associated antigens--e.g., CA19-9, DUPAN 2, and CEA--on the intraoperative frozen-section biopsy during the course of laparotomy. By H&E staining, malignant lesions were identified in four of 19 cases (21%). By the immunostaining method, however, cancer cells were detected in 10 of 19 cases (52.6%). This immunostaining method was particularly useful in defining cancer cells surrounded by dense fibrous connective tissue, in which cancer cells are usually difficult to evaluate by H&E staining. Thus, the application of such immunostaining, together with H&E staining, on the cryostat sections of biopsy specimens may provide important information for the appropriate operative method. Retrospective study of permanent sections revealed that pathological diagnosis by quick immunostaining was more accurate than diagnosis by H&E staining.

Biomarkers, Tumor↗
PubMed1989

Improvement of the rapid immunoperoxidase staining method for intraoperative pathological diagnosis of pancreatic cancer using microwave irradiation.

The rapid immunostaining of gastrointestinal cancer-associated antigens, CA19-9, CEA, DUPAN2, and CA50, for intraoperative pathological diagnosis of pancreatic cancer can be completed in only 13 min by applying microwave irradiation, which was used to accelerate the incubation of the primary antibody. Only 3 s irradiation at 500 W for fresh-frozen sections produced specific antigen staining of greater intensity than that obtained with longer incubation, and tissue preservation was satisfactory with minimal non-specific background staining. This rapid immunoperoxidase staining method on the cryostat section of pancreatic biopsy specimens can provide important information for determining an appropriate operative method for pancreatic cancer patients.

Antigens, Neoplasm↗
PubMed1989

Light and electron microscopic studies of calcitonin gene-related peptide-like immunoreactive terminals in the central nucleus of the amygdala and the bed nucleus of the stria terminalis of the rat.

Light and electron microscopic analysis of calcitonin gene-related peptide (CGRP)-like immunoreactive (LI) terminals in the bed nucleus of the stria terminalis (BST) and the central nucleus of the amygdala (Ce) was carried out using the peroxidase-antiperoxidase method. CGRP-LI fibers were densely distributed in the dorsal subdivision of the lateral BST (BSTL) and the lateral and lateral capsular subdivisions of the Ce, where the CGRP-LI terminals formed symmetrical and asymmetrical axo-dendritic, and symmetrical axosomatic synapses. One of the most characteristic features of the CGRP-LI terminals was the presence of large, long boutons, each of which surrounded a cell soma and made many synaptic contacts. These findings suggest that CGRP exerts a significant influence on neurons in the BSTL and Ce.

Amygdala↗
PubMed1989

Successful pregnancy in a patient with paroxysmal nocturnal hemoglobinuria: case report.

In this report, the maternal and fetal risks in a patient with paroxysmal nocturnal hemoglobinuria (PNH) were evaluated. A patient with PNH carried a pregnancy to successful delivery, with a healthy male infant, and suffered from postpartum cerebral subcortical thrombosis followed by recovery. An elevated level of serum lactate dehydrogenase isoenzyme (alpha-hydroxybutyrate dehydrogenase) was observed during pregnancy; the level returned to normal by delivery. However, the hemoglobin concentration during pregnancy and post-partum was kept at 8 g/dl. This is the first report of a relation between the onset of hemolysis and pregnancy. The management of pregnancy in such patients is discussed.

Adult↗
PubMed1989

Adenocarcinoma and carcinoid developing spontaneously in the stomach of mutant strains of Mastomys natalensis.

Neoplastic and nonneoplastic lesions developing spontaneously in antral and fundic mucosae of stomachs of mutant chamois-coloured Z (130 animals) and Y (67 animals) strains of Mastomys aged 18 to 24 months were examined histologically and histochemically. The Z strain developed both antral lesions (hyperplasia 29.2%; dysplasia 23.8%; adenocarcinoma 17.7%) and fundic carcinoid(s) (72.3%). The antral lesions were limited to the lesser curvature near the pyloric ring. Macroscopically, adenocarcinomas resembled human gastric carcinomas of either Borrmann's type I or II. Histochemically, adenocarcinoma cells were characterised by marked reduction of total mucins produced and predominance of mucins with both periodic acid-Schiff and Alcian blue reactivities (neutral and sialated class II mucins). An infiltrating adenocarcinoma was successfully transplanted into nude mice, reaching the 7th generation of transplantations over 4 years, and retained histological features of the primary tumour. The ultrastructural appearance of growing transplanted tumours supported the reduced production of mucins by adenocarcinoma cells with scarcity of mucin granules and intracellular cysts. However, the Y strain never developed antral lesions like the wild strain, developing fundic carcinoid(s) only. Microscopically, these carcinoids contained argyrophilic nonargentaffin granules, and biochemically produced histamine consistently but no 5-hydroxytryptamine (5-HT, serotonin) like those of the wild strain. Since we found unexpectedly that a line of F2 but not F1 hybrids between wild and Z strains developed the same antral lesions as Z strain, a preliminary experiment was performed to confirm the development of antral lesions in F2 hybrids newly produced by brother-sister mating. Among 41 surviving F2 offspring, 4 (9.8%) developed hyperplasia, 2 (4.9%) dysplasia and none adenocarcinoma. The numbers (6) of animals observed with these lesions approximated to their expected numbers (7.3).

Adenocarcinoma↗