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Biomedical subjects

H Kaji

Publications and source records attributed to H Kaji.

At least 163 records · Page 9Linked to original sources
PubMed1993

Micronucleus induction in mouse peripheral blood reticulocytes by 2,7-diaminophenazine and related compounds.

The peripheral blood micronucleus test using acridine orange (AO) supravital staining was performed with phenazine (Pz), 1-aminophenazine (1-APz), 2-aminophenazine (2-APz) and 2,7-diaminophenazine (2,7-DAPz). Male ICR mice and BDF1 mice were treated intraperitoneally once or twice 24 h apart with each chemical. Irrespective of the number of administrations, Pz and 1-APz were not clastogenic in either mouse strain. In the single treatment regime, 2-APz slightly increased micronucleated reticulocytes (MNRETs) 48 h after 200 mg/kg dosing in ICR mice and 72 h after 400 mg/kg dosing in BDF1 mice. The MNRET frequencies were not enhanced after double treatment in either mouse strain. The single treatment with 2,7-DAPz strongly and dose-dependently induced MNRETs in BDF1 mice, and the incidences of MNRETs, which peaked 48 or 72 h after treatment, were much higher than those in ICR mice. In both mouse strains, the frequencies of MNRETs observed after double treatment with 2,7-DAPz were higher than those after single treatment. The MNRET incidence induced 72 h after first 200 mg/kg dosing in BDF1 mice was 2.21%.

Animals↗
PubMed1993

Hypothenar hammer syndrome in workers occupationally exposed to vibrating tools.

Among 330 vibration-exposed workers, 24 cases of hypothenar hammer syndrome in 29 hands were diagnosed by arteriography. The right hand was involved in 13, the left hand in six, and both hands in five cases. The mean age was 55 years, mean duration of vibration exposure 19.4 years, and mean duration of episodic Raynaud's phenomenon 6.4 years. The vascular lesions of the ulnar arteries were classified into three major types with subtypes. Type 1: stenosis of the superficial palmar arch around the hook of the hamate. Type 2a: occlusion of the superficial palmar arch around the hook of the hamate. Type 2b: occlusion of both superficial and deep palmar arches around the hook of the hamate. Type 3a: occlusion of the ulnar artery at the proximal part of the wrist. Type 3b: occlusion of the ulnar artery near the wrist with the occlusion of the dorsal carpal branch of the ulnar artery.

Adult↗
PubMed1993

Role of dual signal transduction systems in the stimulation of bone resorption by parathyroid hormone-related peptide. The direct involvement of cAMP-dependent protein kinase.

The present study was performed to compare the effect of parathyroid hormone-related peptide (PTHrP) on bone resorption with that of parathyroid hormone (PTH) and clarify the participation of PTHrP-responsive dual signal transduction systems involving cAMP-dependent protein kinase (PKA) and calcium/protein kinase C (Ca/PKC) in the stimulation of bone resorption by PTHrP. Bone resorbing activity was estimated as the number of pits formed on the dentine slice and total area of pits per slice in bone cells derived from 2 week-old mice. Human (h)PTHrP-(1-34) (10(7) M) stimulated bone resorption as potent as hPTH-(1-34) (10(7) M) did. The stimulation of bone resorption by hPTHrP-(1-34) and hPTH-(1-34) was equally blocked by either simultaneous treatment with 10(-8) M Elcatonin (eel calcitonin derivative; from Asahi Chemical Industry, Tokyo, Japan) [corrected] or pretreatment with 10(-7) M [Nle8,18Tyr34]hPTH-(3-34)amide. Rp-cAMPs, an antagonist in the activation of PKA, equally attenuated bone resorption stimulated by PTHrP as well as by PTH. A23187 (10(-7) M) caused a significant stimulation of bone resorption. These findings indicate the direct involvement of PKA activation and a contributory role of an increase in cytosolic calcium in the stimulation of bone resorption by PTHrP and suggest that PTHrP stimulates bone resorption presumably through the same mechanism as PTH does.

Animals↗
PubMed1993

Second messenger signaling of PTH- and PTHRP-stimulated osteoclast-like cell formation from hemopoietic blast cells.

The second messenger signaling mechanisms of parathyroid hormone (PTH)- and PTH-related peptide (PTHRP)-stimulated osteoclast-like cell formation were investigated in mouse hemopoietic blast cells that possessed PTH binding sites. Human (h) PTH-(1-34) or hPTHRP-(1-34) resulted in a dose-dependent stimulation of tartrate-resistant acid phosphatase-positive multinucleated cells (MNC) formation. Pretreatment with [Nle8,18Tyr34]hPTH-(3-34) significantly blocked hPTH-(1-34)- and hPTHRP-(1-34)-stimulated MNC formation. Dibutyryladenosine 3',5'-cyclic monophosphate (10(-4) M) and forskolin (10(-5) M) as well as the stimulatory diastereoisomer of adenosine 3',5'-cyclic phosphorothioate (Sp-cAMPS), a direct activator of adenosine 3',5'-cyclic monophosphate (cAMP)-dependent protein kinase (PKA) (10(-4) M), stimulated MNC formation, and Rp-cAMPS, an inhibitor of PKA activation (10(-4) M), almost completely inhibited MNC formation stimulated by the aforementioned agents but not by 1,25-dihydroxyvitamin D3. Moreover, Rp-cAMPS significantly blocked PTH- and PTHRP-stimulated MNC formation. Treatment with calcium ionophores (10(-8) and 10(-7) M) and phorbol 12-myristate 13-acetate, a protein kinase C (PKC) activator (10(-8) to 10(-6) M), but not 4 alpha-phorbol 12,13-didecanoate, a phorbol incapable of activating PKC, stimulated MNC formation. Two PKC inhibitors [1-(5-isoquinolinylsulfonyl)-2-methylpiperazine dihydrochloride and staurosporine] equally blocked PTH- and PTHRP-stimulated MNC formation. The combined pretreatment with Rp-cAMPS and PKC inhibitors completely blocked PTH- and PTHRP-stimulated MNC formation. Present findings indicate that the activation of PKA and PKC is directly linked to PTH- and PTHRP-stimulated osteoclast-like cell formation from hemopoietic blast cells.

Animals↗
PubMed1993

Design and synthesis of regioselective cleaving reagents for oligonucleotides.

Reaction of methyl 2,3-anhydro-alpha-D-ribofuranoside with allylmagnesium chloride selectively took place at the 2-C position to afford methyl 2-C-allyl-2-deoxy-alpha-D-arabinofuranoside. 1-O-Acetyl-2,3,5-tri-O-benzoyl-beta-D-ribofuranose reacted with allylic alcohols in the presence of BF3.OEt2 to give the corresponding allyl beta-D-ribofuranosides. The allyl group in these compounds were converted into a variety of functional groups which include bromoacetoxy, oxylanyl, tosyloxy, and azide.

Allyl Compounds↗
PubMed1993

[A case report on progressive hematomatous organizing empyema accompanied with intrathoracic hemangioma].

The patient, a 63-year-old woman, who had undergone extra-pleural plombage due to tuberculosis in 1961, was regularly treated for chronic empyema at our outpatient clinic since 1988. The patient who complained of difficulty in breathing because of a recent increase in empyema was admitted to our facility. On a test puncture, pure blood was aspirated without limitation, suggesting the presence of hematoma. On August 5, 1991, pleural decortification, excision of the left upper lobe and thoracoplasty were performed. Perioperative findings included repletion of hematoma and sphacelus in the lumen of thick fibrous capsule, with partial subcutaneous fenestration. Pathologically, cavernous hemangiomas were observed dispersely under the capsule.

Empyema, Pleural↗
PubMed1992

The activation of cAMP-dependent protein kinase is directly linked to the stimulation of bone resorption by parathyroid hormone.

The present study was performed to characterize the direct involvement of cAMP in the stimulation of bone resorption by parathyroid hormone (PTH), using Sp-cAMPS and Rp-cAMPS, which were the direct agonist and antagonist in the activation of cAMP-dependent protein kinase (PKA), respectively. Bone resorbing activity was estimated as the number of pits formed on the dentine slice and total area of pits per slice in bone marrow cells derived from 2 week-old mice. Dibutyryl cAMP (dbcAMP)(10(-4)M) and Sp-cAMPS (10(-4)M) caused the remarkable stimulation of bone resorption. Although Rp-cAMPS (10(-4)M) did not affect bone resorption by itself, it significantly inhibited dbcAMP- and Sp-cAMPS-induced stimulation of bone resorption. Moreover, Rp-cAMPS (10(-4)M) antagonized 10(-7)M human PTH-(1-34)-induced stimulation of bone resorption, although it did not affect 10(-8)M 1,25(OH)2D3-induced stimulation of bone resorption. Present study indicates the direct involvement of PKA in the stimulation of bone resorption by PTH.

Animals↗
PubMed1992

Effects of gastric inhibitory polypeptide and glucagon on portal venous and hepatic arterial flow in conscious dogs.

Gastric inhibitory polypeptide (GIP) has considerable structural homology with glucagon, which is known to increase liver blood flow. We compared the effects of GIP on portal venous and hepatic arterial flow with those of glucagon in conscious dogs. Injection of GIP significantly increased portal venous flow in a dose-related manner (by 7%, 15%, and 46% at doses of 1, 100, and 500 pmol/kg, respectively). The increase in portal venous flow induced by GIP and glucagon was comparable; however, the increase in portal venous flow after GIP injection reached its peak significantly earlier than that after glucagon injection. Hepatic arterial flow decreased after GIP injection (by 17%, 21%, and 35% at doses of 1, 100, and 500 pmol/kg, respectively), whereas it was not altered by glucagon. Thus, GIP causes significant changes in both portal venous and hepatic arterial flow in conscious dogs. Although structurally related, GIP and glucagon may influence liver blood flow through different mechanisms.

Animals↗
PubMed1992

HIV-1 reverse transcriptase inhibitor from Phyllanthus niruri.

An aqueous extract of Phyllanthus niruri (Euphorbiaceae) inhibited human immunodeficiency virus type-1 reverse transcriptase (HIV-1-RT). The inhibitor against HIV-1-RT in this plant was purified by combination of three column chromatographies, Sephadex LH-20, cellulose, and reverse-phase high-performance liquid chromatography. The inhibitor was then identified by nuclear magnetic resonance (NMR) spectra as repandusinic acid A monosodium salt (RA) which was originally isolated from Mallotus repandus. The 50% inhibitory doses (ID50) of RA on HIV-1-RT and DNA polymerase alpha (from HeLa cells) were 0.05 microM and 0.6 microM, respectively, representing approximately a 10-fold more sensitivity of HIV-1-RT compared with DNA polymerase alpha. RA was shown to be a competitive inhibitor with respect to the template-primer while it was a noncompetitive inhibitor with respect to the substrate. RA as low as 10.1 microM inhibited HIV-1-induced cytopathogenicity in MT-4 cells. In addition, 4.5 microM of RA inhibited HIV-1-induced giant cell formation of SUP-T1 approximately 50%. RA (2.5 microM) inhibited up to 90% of HIV-1 specific p24 antigen production in a Clone H9 cell system.

Antigens, Viral↗
PubMed1992

Qualitative and quantitative changes in islet cells of autotransplanted pancreas in dogs in relation to glucose metabolism.

This study was conducted to clarify the quantitative and qualitative changes in the cells of the islets of Langerhans in the autotransplanted pancreas in dogs and to correlate these changes with alterations of glucose tolerance. The left lobe of a canine pancreas was transplanted into the left iliac fossa. The splenic vessels were anastomosed to the left iliac vessels. The pancreatic duct was left open to the peritoneal cavity. Open biopsies of the autotransplanted pancreas were performed 3, 7, 11, and 14 weeks after transplantation. The islets in the transplanted pancreas were examined ultrastructurally; B-cells, A-cells, and D-cells were identified immunohistochemically and their percentages were determined. Intravenous glucose tolerance tests were performed 3, 5, 7, 11, and 14 weeks after operation, and several indexes (K values and integrated response and increased values for baseline serum and immunoreactive insulin) were calculated. Fibrosis of the transplanted pancreas progressed after transplantation. The percentage of B-cells fell significantly (p < 0.01), whereas that of A- and D-cells did not have significant changes. The ultrastructural study revealed an increase in collagen bundles, degranulation of B-cells, and marked preservation of A-cell granules 3 weeks after transplantation. B-Cells with dark cytoplasm were found 7 weeks after operation. In contrast, clusters of immature B-cells were seen in some sections of the pancreas 14 weeks after autotransplantation. The integrated response in baseline serum was increased significantly (p < 0.01), and the K value was decreased significantly (p < 0.01) 11 weeks after autotransplantation when compared with the initial posttransplant period.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Effects of ethanol and wine on hepatic arterial and portal venous flows in conscious dogs.

The effects of ethanol and wine on hepatic arterial and portal venous flows were examined in conscious dogs. Ethanol was given intravenously or intragastrically, and red wine (ethanol: 14%) was given intragastrically over 30 min. Intravenous ethanol (0.8 g/kg) and intragastric ethanol (14% vol/vol) increased hepatic arterial flow, which remained elevated for 60 min after the cessation of ethanol administration. Ethanol also increased portal venous flow. Portal venous flow returned gradually toward basal levels after the cessation of intravenous ethanol infusion, whereas it remained elevated even after the cessation of intragastric ethanol. Intragastric wine increased hepatic arterial and portal venous flows. In contrast to intragastric ethanol, hepatic arterial flow continued to rise after the cessation of intragastric wine infusion, while portal venous flow returned toward basal levels. We conclude that, though both ethanol and wine increase hepatic blood flow, the responses of hepatic arterial and portal venous flows differ substantially among intravenous ethanol, intragastric ethanol and intragastric wine.

Animals↗
PubMed1992

[Immunohistochemical and ultrastructural study on the islet of autotransplanted pancreas in dogs].

This study was conducted to clarify the quantitative and qualitative changes of the islet cells of Langerhans in the autotransplanted pancreas. The left lobe of the canine pancreas was autotransplanted to the left iliac fossa with pancreatic duct left open to the peritoneal cavity. Fibrosis of transplanted pancreas progressed after transplantation. B-cell ratio was decreased significantly (p less than 0.01) whereas A-cell ratio and D-cell ratio showed no significant changes. Ultrastructural study revealed the increase of collagen/bundle, degranulation of B-cells and well preservation of A-cell granules at 3 weeks after operation. B-cells with dark cytoplasm were found at 7 weeks after operation which indicate the dysfunction of B-cells. In contrast, clusters of immature B-cells appeared on some sections obtained from the pancreas 14 weeks after autotransplantation. On the other hand, K-values were decreased significantly 7 weeks after operation (p less than 0.05). sigma BS (integrated response value of serum glucose level during IVGTT) was increased significantly (p less than 0.01) in addition to the decrease of K-values (p less than 0.01) at 11 weeks after operation. It proved that any indices at 14 weeks after operation showed no significant changes from the control group. It might be possible to speculate that relatively well preservation of glucose tolerance at 14 weeks after operation is associated with some clusters of immature B-cells observed ultrastructurally.

Animals↗
PubMed1992

[Morphometric study on islet of Langerhans in relation to glucose tolerance in chronic obstructive pancreatitis due to pancreatoduodenal cancer].

Twenty one specimens of the pancreas in the patients who underwent pancreatoduodenectomy or total pancreatectomy for pancreatoduodenal cancer were divided into 4 groups according to the extent of fibrosis (Grade 0-Grade III). Islet cells of serial sections were stained immunohistochemically with calculation of the proportion of B-cells, A-cells, D-cells and PP-cells in the islets of Langerhans. In the pancreatic tissue with the most severe fibrosis (Grade III), B-cell ratio was significantly decreased (p less than 0.01), whereas A-cell ratio was significantly increased (p less than 0.01). Based on the data of oral glucose tolerance test (OGTT) and insulin response test, some indices were calculated (delta IRI/delta BS, sigma IRI/sigma BS, sigma delta IRI/sigma delta BS). In Grade III, sigma delta IRI/sigma delta BS was significantly decreased. A significant positive correlation was observed between B-cell ratio and both delta IRI/delta BS or sigma delta IRI/sigma delta BS, whereas a significant negative correlation was seen between A-cell ratio and sigma delta IRI/sigma delta BS. The present study first demonstrates the significant correlation between the endocrine secretory function of the islets and quantitative changes of the endocrine cells of islets in chronic obstructive pancreatitis due to pancreatoduodenal cancer. The present data strongly suggest that it is possible to estimate the degree of fibrosis and quantitative changes of the islet cells in the patients with pancreatoduodenal cancer by means of calculating the above mentioned indices, especially sigma delta IRI/sigma delta BS.

Blood Glucose↗
PubMed1991

Determination of dimethyl sulphide in blood and adipose tissue by headspace gas analysis.

A method for the headspace analysis of dimethyl sulphide in blood and adipose tissue has been established. Blood (0.2 ml) or adipose tissue (0.5 g) with added dimethyl sulphide was sealed in a 10-ml vial using PTFE sheet to prevent escape of dimethyl sulphide from the headspace. Equilibration was performed at 60 degrees C for 4 h, and 20 microliters of gaseous phase sampled from the headspace was subjected to gas chromatography (with flame photometric detection). Calibration curves were prepared for the two samples. Linearity was observed in the range from 5-10 micrograms to 2 mg.

Adipose Tissue↗