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Biomedical subjects

K Okano

Publications and source records attributed to K Okano.

At least 19 recordsLinked to original sources
PubMed1992

Intracellular signal transduction for interleukin-1 beta-induced endothelin production in human umbilical vein endothelial cells.

The authors investigated the intracellular signal transduction for interleukin (IL)-1 beta-induced endothelin (ET) production by endothelial cells from cultured human umbilical vein (HUVEC). Cultured HUVEC released immunoreactive (iR)-ET into the media in a time-dependent manner and a significant increase of iR-ET production was observed by the addition of IL-1 beta. The stimulating effect of IL-1 beta on iR-ET production was respectively inhibited by protein kinase C (C kinase) inhibitor (H-7), Ca-calmodulin inhibitor (W-7), cyclic AMP-dependent protein kinase (A kinase) inhibitor (H-8) and tyrosine kinase inhibitor (genistain) in a dose-dependent fashion. The data suggested that intracellular signal transduction for IL-1 beta-induced iR-ET production were via such pathways as C kinase, A kinase, Ca-calmodulin and tyrosine kinase in combination or independently, though possible mediation by other pathways cannot be ruled out.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1992

Using microparticle labeling and counting for attomole-level detection in heterogeneous immunoassay.

A new heterogeneous "sandwich" immunoassay utilizing microparticles as labels to realize high sensitivity is described. In this method, antibody fixed on the microparticles reacts with antigen previously trapped on a microplate surface, which makes the antigen molecules visible and countable with an inverted optical microscope. The method is highly sensitive because the reacted single microparticle, therefore single antigen molecule, can be detected. The sensitivity depends both on the reaction efficiency of the immunoreaction and on nonspecific adsorption of the microparticles on the microplate surface. Therefore, the protocol for preparing microparticle having antibody on the surface and a microplate having capture antibody was investigated to realize high sensitivity. Carboxylated microparticles of 0.76 microns in diameter were conjugated with affinity-purified antibody using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. It was determined that 1 g microparticles had 880 micrograms antibody (approximately 1100 antibody molecules per 1 microparticle). The immunoreaction efficiency reached 18% at 1 x 10(-13) mol/liter antigen concentration. The lower detection limit was 3.1 x 10(-14) mol/liter (1.6 amol) using human alpha-fetoprotein as a model antigen.

Adsorption↗
PubMed1992

Mechanism of accumulation of macrophages in galactosamine-induced liver injury: effect of lipoxygenase inhibitors on chemotaxis of spleen cells.

In an attempt to clarify a mechanism of macrophage infiltration in galactosamine-induced hepatic injury, we investigated chemotactic factor(s) generated by murine hepatocytes exposed to galactosamine. Hepatocytes, isolated from murine liver by perfusion and digestion with collagenase, were incubated with galactosamine. Conditioned medium was collected 24 h later and chemotaxis of murine spleen cells was measured by stimulation of the conditioned medium using a modified Boyden chamber. Chemotactic activity was demonstrated in the conditioned medium of hepatocytes exposed to more than 3 mM galactosamine. Chemotactic activity of the conditioned medium was not reduced after freeze-thawing, and found to be dialyzable (molecular weight < 12,000). Trypsin (0.25%, 37 degrees C, 30 min) or heat (56 degrees C, 30 min) treatment reduced chemotactic activity of the conditioned medium. Furthermore, chemotaxis of spleen cells was decreased in the presence of lipoxygenase inhibitors (azelastine, ketotifen). These results suggest that accumulation of macrophages in the liver could be mediated by chemotactic factor produced by the galactosamine-treated hepatocytes, and that this mechanism may contribute to the pathogenesis of hepatic injury induced by galactosamine.

Animals↗
PubMed1992

[The sensitivity and specificity of various peroxidase stains--the difference between DAB and 3AC stainings].

FAB Cooperative Group has cited 3 or higher percentage in the peroxidase (PO) activity as one of criteria for the diagnosis of acute myeloid leukemia. We have previously reported in two cases of acute myelomonocytic leukemia (M4) that there was a great difference between 3,3'-diaminobenzidine (DAB) and 3-amino 9-ethyl carbazole (3AC) as substrates for PO reaction. In order to confirm the previous result, we extended the cases and compared the PO activities in blood films taken from several leukemic subjects, which were fixed with various kinds of fixatives, using DAB and 3AC as substrates. Their peroxidase activities were also determined through electron microscopy (EM-PO). There were no differences among fixatives and substrates in staining normal granulocytic cells (neutrophils and monocytes) and cells in 13 cases of leukemia, except for two cases, one with M4 and the other with relapse of M2. These showed the highest PO activity with 3AC staining and 10% formaldehyde acetone buffer for fixation. Besides, all types manifested the highest positivity in EM-PO, except for the relapse of M2 that showed a higher positivity in the peroxidase stain by 3AC staining, 10% formaldehyde acetone buffer fixation than the EM-PO. Unlike other leukemic blasts PO reaction products of blast cells of the two cases showed a scattered distribution of microscopic granules. These findings suggested the difference, which was seen in the previous reports, of the PO stain between two substrates might be due not only to sensitivity for staining but to the presence of some heterogeneity such as isoenzyme in the myeloperoxidase.

3,3'-Diaminobenzidine↗
PubMed1992

[Immunological detection of fecal occult blood-follow up study on patients with positive testing].

To evaluate its clinical utility in the early detection of colorectal diseases, we carried out the immunological fecal occult blood test in 922 patients and monitored the clinical course of the 87 patients in whom it was positive. Thirty-five (40.2%) of these patients underwent subsequent X-ray and colonoscopy, and colorectal cancer was detected in 8 (20%). Our findings confirm the clinical usefulness of this test.

Colorectal Neoplasms↗
PubMed1992

[Metabolite of 15-p-iodophenyl-3(R,S)-pentadecanoic acid (123I) in blood and urine].

We analyzed metabolites of 123I-BMIPP in blood and urine using rats, rabbits and human, while human samples were obtained from normal volunteers of Phase I clinical study. We estimated metabolic pathway of 123I-BMIPP as a myocardial metabolic imaging agent. Radioactivity accumulated in heart after administration gradually decreased and was mainly excreted to bladder via kidneys. The main radioactive component in blood was 123I-PIPA for any species and the urinary components were metabolic conjugates of 123I-PIPA. As results of these studies, we considered that 123I-BMIPP was metabolized to 123I-PIPA by alpha-oxidation process for the first step, follow by beta-oxidation process, then 123I-PIPA was released to blood from tissues. Moreover, 123I-PIPA in blood was conjugated with other compounds and excreted to the bladder.

Animals↗
PubMed1979

Discrepancies between the doses of cholecystokinin or caerulein-stimulating exocrine and endocrine responses in perfused isolated rat pancreas.

The effects of highly purified natural porcine cholecystokinin (CCK) and synthetic caerulein on the rate of flow of pancreatic juice, the rate of output of amylase, and the rate of release of immunoreactive insulin (IRI) and immunoreactive glucagon (IRG) were simultaneously investigated in the isolated perfused rat pancreas. The maximal flow rate of pancreatic juice was obtained with concentrations of CCK ranging from 0.5 to 10 mU/ml, whereas amylase output was maximal at CCK concentrations from 1 to 10 mU/ml. Caerulein at concentrations of 0.05-1 ng/ml induced a similar maximal flow rate and amylase secretion. Supramaximal stimulatory concentrations of these peptides resulted in lower rates of release of fluid and amylase than with the maximally effective concentrations. Stimulation of IRI and IRG release was elicited only with concentrations of peptides supramaximal for effects on the exocrine responses. The demonstration of very similar discrepancies between the doses of caerulein required to elicit maximal exocrine responses and those required to elicit endocrine responses provide strong evidence that the pattern of the effect of the porcine CCK is accounted for by CCK itself. Although caerulein had no influence on IRI response when superimposed on 100 or 150 mg/100 ml glucose stimulation, preperfusion of caerulein led to a significant enhancement of IRI response to a subsequent glucose stimulation in both phases. The augmentation effect was completely separate from the direct IRI-stimulating effect of caerulein, because the CCK-like peptide requires no glucose for insulinotropic action. Because the concentrations of the peptides necessary for stimulation of endocrine responses were inhibitory in their effects on exocrine responses, it may be inferred that it is unlikely that the endocrine effect is physiologically important, though the results of caerulein for augmenting glucose-stimulated IRI release suggests a possible role for CCK in carbohydrate metabolism.

Amylases↗
PubMed1978

Pancreatitis-like isoamylase pattern in normal persons.

On the assumption that a rise in the pancreatic type isoamylases may not necessarily indicate underlying pancreatitis, genetic studies of human serum and urinary amylase isoenzymes have been performed with the use of electrophoresis. Although the preponderant increase in the two principal pancreatic isoamylases Amylase-1 and 2 has been accepted to be a specific index of pancreatic involvement, 1.68% of normal persons had Amylase-2 with an elevated amylase activity (named "Dominant Amylase-2") up to the same levels as the major isoenzymes. Results of pancreozymin-secretin test and other laboratory findings of these persons with Dominant Amylase-2 were all within normal ranges. Pedigree studies confirmed an autosomal dominant mode of inheritance for this variant. The important of serial determination and pedigree investigations has been shown to distinguish normal persons having Dominant Amylase-2 from patients with pancreatitis without elevated amylase activity. The existence of an inherited trait of pancreatitis-like isoamylase pattern in healthy individuals must be born in mind before coming to a conclusion when amylase isoenzymes are used for clinical medicine, though preponderance of the pancreatic type isoenzymes in serum and urine has been revealed to be a characteristic finding in pancreatitis. Knowledge of amylase genetic polymorphism provides a scientific basis for amylase isoenzyme interpretation.

Acute Disease↗
PubMed1978

[Effect of caerulein on pancreatic endocrine and exocrine secretion from the perfused rat pancreas (author's transl)].

Several investigations in vivo and in vitro have shown that gastro-intestinal hormones stimulate insulin secretion. However, the reports on the insulinotropic activity of pancreozymin are contradictory. The conflicting results are probably due to the fact that pure native preparation of this hormone has not been obtained in "physiologic" doses. In the present study this problem has been investigated by exposing rat pancreas to caerulein in vitro. Caerulein, an active decapeptide isolated from the skin of the Australian amphibia Hyla caerulea, resembles pancreozymin in chemical structure, including C-terminus. This active polypeptide of nonmammalian origin has been shown to possess all the biological activities of pancreozymin. The present investigation was undertaken to evaluate the significance of the interactions of exocrine and endocrine pancreas using perfused rat pancreas in vitro. Biphasic insulin release was demonstrated with caerulein at concentrations higher than 1 ng/ml. Insulin response of the first phase was proportional to the dose up to 1 microgram/ml. The second phase of insulin release was, however, almost constant, regardless of the concentrations of caerulein. Release of glucagon was stimulated by the same concentrations of caerulein which stimulated insulin release. Maximal response of the pancreatic amylase and pancretic juice output were observed with 1 ng/ml of caerulein. With higher doses, significantly less secretory responses were observed. The dissociation of the response to caerulein between endocrine and exocrine pancreas was found.

Amylases↗
PubMed1978

Clinical evaluation of the pancreatitis-like isoamylase pattern in normal persons.

Amylase isoenzyme analysis of serum and urine has been performed in 4001 normal persons and 500 patients with various disease using electrophoresis on thin layer polyacrylamide gel. Although elevation of amylase activity in amylase-1 and 2 has been reported to be the specific findings in patients with pancreatitis, 1.69% of normal persons had an elevated Amylase-2(named "Dominant Amylase-2") up to the same levels as major isoenzymes (Amylase-1 and 3), along with Amylase-1. Pedigree study confirmed an autosomal dominant mode of inheritance for Dominant Amylase-2. Knowledge of the genetic polymorphism is of importance in clinical assessment of amylase isoenzymes in patients having an elevated Amylase-2 suggestive of pancreatitis. Predominance of the pancreatic components in serum and urine has been revealed to be a specific index of pancreatic involvement. However, the existecne of an inherited trait of pancreatitis-like isoamylase pattern in healthy individuals must be borne in mind. On the basis of the present study, it may be concluded that a rise in the pancreatic type isoenzymes may not necessarily indicate underlying pancreatitis, especially in the absence of elevated amylase and lipase levels.

Acute Disease↗