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Biomedical subjects

K Oka

Publications and source records attributed to K Oka.

At least 415 records · Page 23Linked to original sources
PubMed1989

Interaction of lipoprotein lipase with heparin.

The hydrolysis of triglyceride-rich plasma lipoproteins is initiated by lipoprotein lipase (LPL) located at the luminal surface of endothelial cells. We previously reported that LPL binds to cultured endothelial cells with a Km of 2.7 x 10(-7) M and that this binding is inhibited by heparinase, heparin, or heparan sulfate. We and others recently isolated LPL cDNAs from various animals. The deduced amino acid sequence from cDNA sequence is highly conserved among animal species. The structural analysis revealed two regions rich in basic amino acid residues at the carboxyl-terminal region that may interact with the anionic heparin-like molecules. Amino acid residues 292 to 300 of bovine LPL are extremely similar to the reported heparin binding sites on apolipoproteins B-100 (amino acid residues 3359-3367) and E (amino acid residues 142-150).

Amino Acid Sequence↗
PubMed1989

[Acid-base fractionation of lipophilic components in human urine and their high-performance liquid chromatography equipped with multichannel ultraviolet detector: an application to xanthine derivatives].

Column extraction technique was applied to acid-base fractionation of urinary lipophilic components. The acidified urine was retained on an extraction column packed with diatomaceous earth granules. Extraction solvent passed through the column was introduced directly into alkaline columns to fractionate strong and weak acidic components, the former being trapped on sodium hydrogen carbonate and the latter on sodium hydroxide column. Neutral components were eluted out without any chemical interaction with the support reagents. Acidic components retained in the column were recovered after acidified with acetic acid. Each fraction thus obtained was analyzed by silica gel high performance liquid chromatography equipped with a multi-channel ultraviolet detector using a solvent system consisted of 0.2% distilled water, 0.2% acetic acid, 15% ethanol and appropriate volume of n-hexane. Thus the comparative chromatographic studies of these three fractions became very easy. In our experiment, urinary components were extracted and chromatographed in the order of their partition coefficients. The method was applied to xanthine derivatives after the administration of caffeine tablets to a healthy volunteer.

Chromatography, High Pressure Liquid↗
PubMed1989

Effects of SCH23390 injection into the dorsal striatum and nucleus accumbens on methamphetamine-induced gnawing and hyperlocomotion in rats.

The effects of SCH23390, a selective D1 receptor antagonist, injected into either the dorsal striatum or nucleus accumbens on methamphetamine-induced stereotyped gnawing and hyperlocomotion in rats were investigated. SCH23390 injected into the dorsal striatum did not alter the gnawing induced by both methamphetamine and apomorphine. However, SCH23390 injected into the nucleus accumbens significantly reduced methamphetamine-induced gnawing without altering the effects of apomorphine. Injection of SCH23390 into the nucleus accumbens reduced the hyperlocomotion produced by methamphetamine more markedly than injection of SCH23390 into the dorsal striatum.

Animals↗
PubMed1989

[Study on the physico-chemical properties of fluoride gel in application of freeze-drying gelatin gel method (tray method)].

As a means of studies of securing freeze-drying method by application of tray for prevention of white spots, decalcification and secondary caries of enamel, which may develop during and after orthodontic treatment, comparison and review were made on physico-chemical properties of fluoride gel to be used for gelatin gel method and freeze-drying gelatin gel method (control group gel and experimental group gel), and the following results were obtained: 1. Physical properties As the results of naked-eye observations, morphological observations through scanning electron microscope and measurements of gelly strength and viscosity, no distinct difference between control and experimental group gel was noted. 2. Chemical properties The qualitative analyses of fluoride ion with ion chromatogram and pH measurement were carried out, and consequently experimental group gel indicated similar values to control group gel. From the foregoing results, it was learned that no significant difference in their physico-chemical properties was clearly confirmed between control and experimental group gel, and it was suggested that similarly to control group gel, experimental group gel would be an effective gel substance as gel media for the formation process of fluorapatite or the reinforcement method of tooth enamel.

Fluorides, Topical↗
PubMed1989

[Study on frictional characteristics of KB horizontal brackets. A comparative study of kinetic frictional forces to be caused between various kinds of brackets and wires].

KB horizontal brackets were designed to tip no more than 6 degrees at the maximum. This tipping amount is based on the idea of reducing friction between a wire and brackets to allow the effective tooth movement of the Begg technique even with horizontally long brackets, and does not originate in the concept of carrying out tipping movement. Thereon, experimental measurements by use of Rheometer were conducted to review for comparison of the kinetic frictional forces caused between various wires and the following four types of brackets; KB horizontal brackets, Tip edge brackets, Straight edge brackets and Begg brackets. 1. In case of utilizing ribbon arch wires and rectangular wires, no significant difference was acknowledged among Tip edge, KB horizontal and Straight edge brackets. 2. There proved to be a reduction in the kinetic frictional forces by incorporating tip into the edgewise slots, when using smaller dimensions of the wires which call for the effective tooth movement, however, Begg brackets (in conjunction with Ordinary T-pins and/or Safety T-pins) showed the small value which is far less than that of the three kinds of brackets.

Orthodontic Appliances↗
PubMed1989

Intracytoplasmic localization of CD3 antigen in NKH1+ azurophilic granular T-lymphoblastic lymphoma cells.

The intracytoplasmic localization of CD3 antigen was examined in azurophilic granular T-lymphoblastic lymphoma cells obtained from a 27-year-old female. Examination by flow cytometry and an immunohistological method revealed that the surface phenotype of the lymphoma cells were NKH1+, CD5+, CD7+, CD1-, CD2-, CD4-, CD8- and CD16-. CD3 was not detected on the cell-surface by flow cytometry but was found in the cytoplasm using the immunohistological method. CD3 was detected in the perinuclear space and rough endoplasmic reticulum (rough ER) by an immunoelectron microscopic study. An electron microscopic observation of the granules revealed lysosomal structures with low electron density. The lymphoma cells proliferated when cultured in the presence of interleukin-2 but showed no NK (K562) activity before and after culture. The molecular size of metabolically labeled intracytoplasmic CD3 precipitated by Leu 4 monoclonal antibody was identical to that of normal CD3. These results indicate that the lymphoma cells are neoplastic counterparts of immature thymocyte at a very early stage of differentiation and may be related to the lineage of CD3+ NKH1+ T-lymphocyte.

Adult↗
PubMed1989

[The effect of the elastase on aminonucleoside nephrosis].

In this paper, we studied the effect of elastase on aminonucleoside (AN) nephrosis which is considered a model of focal glomerular sclerosis (FGS). Elastase is an enzyme which disintegrates elastin, discovered by Balo, and used in the treatment of arteriosclerosis and hyperlipidemia. It has also been known to improve metabolism of acid mucopolysaccharides, so, this study focused on metabolic improvement. Three groups of male Sprague-Dawley rats were studied and observed at regular intervals; 30, 60, 90 days. The ANE group (AN + elastase) was administered one shot of AN (10 mg/100 g B.W.) during the test interval, while elastase (5 mg/kg B.W.) was injected 5 days/week for the entire test interval. The AN group was administered one shot of AN only. The third group was a control (C). The following results were observed: (1) Focal segmental hyalinosis and sclerosis (FSHS); ANE group was weaker than AN group. (2) Other significant qualifying glomerular changes (vacuolar change and hyaline droplets of the epithelial cells, adhesion, and foam cells); ANE group was weaker than AN group. (3) Anion loss in GBM was shown by a lack of colloidal iron staining under light microscopy, and by a lack of PEI particles under electron microscopy; there was significantly less anion loss with ANE group, than with AN group. The findings suggest that elastase has an affect on the metabolism of acid mucopolysaccharide and collagen in sclerotic lesion, and may restrain the progress of amino-nucleoside nephrosis.

Animals↗
PubMed1989

Endogenous digoxin-like activity of mammalian-lignans and their derivatives.

A comparative study was made on the endogenous digoxin-like activity of sixteen mammalian-type lignan derivatives including enterolactone and enterodiol. Cross-reactivity to antidigoxin antibody, inhibition of dog kidney Na+,K+-ATPase, and ouabain displacing activity against [3H]ouabain binding to human erythrocytes on the part of these derivatives were examined and compared in all cases with that of ouabain. meso-2,3-Dibenzylbutane-1,4-diol (meso-HA-1) was found to possess the most potent cross-reactivity to antidigoxin antibody. Several lignans, particularly HA-1 (either meso or dl), dl-2,3-bis(3-methoxybenzyl)butane-1,4-diol(HA-4), dl-2,3-bis(3,4-dimethoxybenzyl)butane-1,4-diol(HA-10), dl-2,3-bis(3,4-dimethoxybenzyl)-1,4-dimethoxybutane(HA-11), and trans-2,3-bis(3,4-dimethoxybenzyl)-gamma-butyrolactone(HA-14) were capable of inhibiting Na+,K+-ATPase activity with IC50 at a concentration less than 5 x 10(-4) M. Meso-HA-1, HA-11 and HA-14 also showed [3H]ouabain displacement activity with IC50 at a concentration of 10(-4)-10(-3) M. These determinations of activity were made at doses 100-1000 times those of ouabain. The synthetic lignans are considered to derive in vivo from plant material usually present in fibrous food. Based on the data obtained, some lignans may possibly be endogenous digitalis-like substances.

Animals↗
PubMed1989

[Pathomorphological studies on arterial cushion. 2. Aminonucleoside nephrotic rat].

The present study is an attempt to solve the problem of pathogenesis of focal glomerular sclerosis (FGS), especially in juxtamedullary cortex, we were investigated by measurement of luminal diameters of afferent arterioles (Aff), efferent arterioles (Eff) of numerous glomeruli, arterial cushion (AC), afferent arterioles (AC-aff) at a region of branching arteries from the interlobular arteries, using scanning electron micrographs of methyl methacrylate casts of intrarenal arteries of aminonucleoside nephrotic rats. As regards luminal diameters, Eff were nearly equal Aff in minor glomerular abnormalities (Minor). Nevertheless Eff of glomeruli with segmental sclerosis (FSHS) were smaller than Aff (t-test). AC with FSHS were smaller than ones of Minor, statistically (t-test). The results of these examination, the cushion may be important factor for the regulation of blood flow in sclerotic glomeruli.

Animals↗
PubMed1989

Expression of enolases in B cell tumors.

Frozen lymph node biopsy specimens from 38 patients with B cell tumors, including 5 with childhood non-T-ALL and 3 with reactive lymphadenitis, were investigated using a direct immunohistochemical method to detect alpha-, beta- and gamma-enolases. alpha-Enolase-positive cells were not observed in reactive lymphadenitis. On the contrary, almost all the lymphocytes including germinal center cells were positive for beta-enolase. Small lymphocytes in the mantle zones were negative, centrocytes were negative or weakly positive, the majority of centroblasts were strongly positive and the remaining were weakly positive for gamma-enolase. In all 5 patients with childhood non-T-ALL, leukemic lymphocytes were strongly positive only for alpha-enolase. In all 33 patients with B cell lymphoma, lymphoma cells were positive for beta-enolase. In many patients with follicular lymphoma, lymphoma cells were positive only for beta-enolase. Four of five patients with malignant lymphoma, diffuse, small cleaved cell, showed the reactivity of alpha-, beta+, gamma+-enolases in lymphoma cells. Our results suggest the possibility of the two isoenzyme switches from alpha- to beta-enolase and from alpha- to gamma-enolase in the B lymphocyte lineage accompanying differentiation, similar to those of skeletal muscles and neurons.

B-Lymphocytes↗
PubMed1989

Prognostic significance of Langerhans' cell infiltration in radiation therapy for squamous cell carcinoma of the uterine cervix.

Prognostic significance of Langerhans' cell (LC) infiltration in cancer nests was studied in 391 patients with squamous cell carcinomas of the uterine cervix. They were treated with radiation therapy alone. Langerhans' cells were identified by immunohistochemical staining for S100 protein. Langerhans' cells were present mainly in the intercellular spaces of tumor cells. The LC infiltration rates were higher in stage II (31.0%) or stage III (26.9%) than in stage I (17.5%) or stage IV (7.8%). The patients with LC infiltration showed a significantly better five-year survival rate than those without LC infiltration (68% and 56.1%, respectively). This significant difference was observed especially in stage III and it was suggestive in stage IV diseases. These results suggest that LCs in cancer nests may play a significant role in the immunologic defense against cancer in advanced stage of cervical cancer.

Age Factors↗
PubMed1989

Childhood Ki-1 lymphoma. A report of two cases.

Two cases of childhood Ki-1 lymphoma occurred with the expression of Ki-1+/HLA-DR+/IL-2R+/EMA+/Leu-M1-/pan-T antigens-/pan-B antigens- in neoplastic cells. Patient 1 with nodular skin lesions expressed Leu-2a+ in the neoplastic cells and died 14 months later. Patient 2 with lymph node swelling and hepatosplenomegaly exhibited Leu-3a+ in the neoplastic cells and remains free of disease. The Leu-2a+ (case 1) or Leu-3a+ (case 2) findings suggest that the neoplastic cells in both cases were derived from T-lymphocyte lineage. However, Southern's blot analysis did not reveal any clonal rearrangements of T-cell receptor genes in the autopsy material from case 1. The Leu-3a+/Mcs-2+ finding in case 2 may indicate that the neoplastic cells were derived from monocyte/macrophage lineage.

Child, Preschool↗
PubMed1989

[Enhancement of enamel crystallinity with gel method during orthodontic treatment. The 1st report: Application of electron probe X-ray microanalyser].

This paper is to review the gel method of strengthening tooth enamel substance around bonded brackets and morphological observations and elemental analyses of the chopped cross section of the three below-mentioned groups were carried out by electron probe X-ray microanalyser (EPMA) for a relative review. Group I: bracket-bonded extracted tooth enamel in application of the silica-hydro gel method. Group II: bracket-bonded extracted tooth enamel in application of the gelatin gel method. Group III: bracket-bonded extracted tooth enamel in application of neither method. The results obtained were as follows: 1) As a result of making morphological observations through secondary electron image and back scattered electron image, the adhesive condition of the brackets and the state of the chopped cross sections were favorable and these combined observation proved effective as a supplementary method of elemental analysis. 2) Through qualitative analyses, Ca, P, F, O, Na, Mg and Cl were recognized as content elements on the experimental side (the non-bracket side) as well as on the control side (the bracket side) from group I through III. 3) In making ultrahigh-speed wide-area surface analyses (elemental concentration map), the incorporation of F was recognized from enamel cuticle to approximately 200 microns in group I and to 50-100 microns in group II, and the distribution of Ca was totally consistent, and P showed the slight downward trend from enamel cuticle to dentoenamel junction. 4) The incorporation of F was acknowledged to be until 150-200 microns on the experimental side of group I and to be until 80 microns on the experimental side of group II by line analyses. 5) As regards F on the experimental and the control side in group I as well as in group II through a quantitative analysis, the experimental side clearly revealed a high concentration of F and acknowledged 1% level to be a significant distinction. From the foregoing results through the electron probe X-ray microanalyser, strengthening tooth enamel substance in vitro by application of the gel method proved to be effective, and the silica-hydro gel method was indicated to be superior to the gelatin gel method.

Dental Bonding↗
PubMed1989

[Pathomorphological studies on arterial cushion. 1. Rat normal kidney].

The present studies are an attempt to elucidate the vulnerability of focal glomerular sclerosis (FGS). The distribution and morphology of the arterial cushions were studied in rat renal arteries by light microscopy, transmission electron microscopy and scanning electron microscopy (SEM) using of the renal vascular casts. The arterial cushions were observed at a region of the branching arteries from the arcuate arteries and the interlobular arteries. They were extensively demonstrated mainly in the mid cortex and juxtamedullary cortex by the serial sections, but not in the subcapsular cortex. The arterial cushions showed valve-like protrusions and consisted of three components, such as the endothelial cells, the smooth muscular cells and the interstitial ground substances, electron microscopically. The cushions are covered by the endothelial cells which often showed various variation in thickness. Also these had deep processes which elongate into the interior of the cushions. The cells of interior portions of the cushions were modified smooth muscular cells. These cells contained numerous myofibrils and a large number of scattered glycogen granules. No nerve fibers were seen within the cushions. The modified smooth muscular cells were embedded in a loose matrix (probably acid mucopolysaccharides) which contained strands of basement membrane like material. The cushions were observed on the wall of the arcuate and interlobular arteries in the cortex except for subcapsular cortex by SEM. They showed elongated indentation surrounding lumen of their arteries. These results of the observation, the cushion may be important factor for the regulation of blood flow in small arteries and arterioles. The disorder of autoregulation of interlobular arteries due to dysfunction of the cushions with anionic loss were assumed to be one of the important factor in progress to the glomerular sclerosis.

Animals↗
PubMed1989

Antiproliferative effects of synthetic and naturally occurring flavonoids on tumor cells of the human breast carcinoma cell line, ZR-75-1.

An examination was made of the effects of 21 synthetic and naturally occurring flavonoids on the in vitro growth of cells of the human breast carcinoma, ZR-75-1. In all cases, antiproliferative effects were noted, with an IC50 ranging from 2.7 to 33.5 micrograms/ml, except for the isoflavonoid, daidzin (IC50 greater than 50 micrograms/ml). No significant structure-activity relationship among the compounds could be found. Flavone, 6-hydroxyflavone and 4',5,7-trihydroxyflavone (apigenin) were the most potent with IC50 of 2.7, 3.4, and 3.5 micrograms/ml, respectively. The flavonoid effects observed here were not due to cytostatic action alone, since cell death was found to increase dose-dependently, according to the results of a dye exclusion test.

Breast Neoplasms↗