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Biomedical subjects

S Miyauchi

Publications and source records attributed to S Miyauchi.

At least 73 records · Page 4Linked to original sources
PubMed1996

Protective efficacy of sodium hyaluronate on the corneal endothelium against the damage induced by sonication.

The protective efficacy of sodium hyaluronate (Na-HA) on the corneal endothelium against the damage induced by sonication was investigated using enucleated rabbit eyes and Na-HA fluorescence labeled with 5-aminofluorescein (FA-HA). The anterior chamber was reformed by injecting a 1% solution of FA-HA, and then sonication, irrigation and aspiration were performed in the anterior chamber using a phaco-needle attached to phacoemulsification and aspiration (PEA) equipment. The protective efficacy was evaluated by the area of damaged corneal endothelium. When the anterior chamber was reformed by the solution of FA-HA with a molecular weight of 2010 x 10(3) (FA-HA (2010 x 10(3) group), most of the FA-HA was eliminated within 20 seconds after starting the irrigation and aspiration, and the area of damaged endothelium was the same with the case when the FA-HA was not pre-injected (Control group). On the other hand, when the anterior chamber was reformed by the solution of FA-HA with a molecular weight of 1130 x 10(3) (FA-HA (1130 x 10(3) group), the FA-HA was gradually eliminated after mixing with an irrigating solution, and the area of damaged endothelium was significantly smaller than those of the Control and FA-HA (2010 x 10(3)) groups. These results suggest that the corneal endothelial damage induced by PEA can be avoided by pre-injecting a viscoelastic material which can remain in the anterior chamber during PEA.

Animals↗
PubMed1996

The effect of sodium hyaluronate on the growth of rabbit corneal epithelial cells in vitro.

The effect of sodium hyaluronate (Na-HA) on the growth of rabbit corneal epithelial cells was investigated in vitro by using MTT assay and [3H]-thymidine incorporation. Na-HA, with a molecular weight of 86 x 10(4), enhanced the growth of the corneal epithelial cells cultured on a fibronectin (FN) coated dish, but when cells were cultured on a noncoated dish, Na-HA did not enhance the growth of the cells. Na-HA, labeled with 5-aminofluorescein (FA-HA), bound to the corneal epithelial cells, and the CD44-like molecule was identified on the cells by using a monoclonal antibody, OS/37. Furthermore, the binding of FA-HA to the cells was significantly inhibited by the monoclonal antibody. These results suggest that Na-HA binds to the CD44-like molecule associated with FN and then enhances the growth of the corneal epithelial cells.

Animals↗
PubMed1996

Immunohistochemical observations on a possible ameloblastic fibro-odontoma.

An ameloblastic fibro-odontoma which occurred in the mandible of a 3-year-old Japanese boy is reported together with immunohistochemical findings. Histologically, the tumor consisted of an ameloblastic fibroma-like area and some typical complex odontoma-like areas. The epithelial islands in the ameloblastic fibroma-like area showed different developmental stages of the epithelial-connective tissue interface. Immunohistochemical examination revealed that all epithelial components in the ameloblastic fibroma-like area showed expression of CK 8, CKs 13, 16, CK 14, CK 18 and CK 19, and coexpression of these cytokeratins and vimentin. These findings suggest that even the epithelial component without obvious epithelial-mesenchymal induction showed the final cell differentiation of the enamel organ with the potential for epithelial-mesenchymal induction.

Cell Differentiation↗
PubMed1996

Activation of human presupplementary motor area in learning of sequential procedures: a functional MRI study.

1. Using functional magnetic resonance imaging, we investigated the neural correlates of sequential procedural learning. During the test scans the subjects learned a new sequence (position or color) of button presses; during the control scans they pressed the buttons in any order. The comparison of the test and control scans was expected to reveal the neural activities related to learning, not sensory-motor processes. 2. We found that a localized area in what we regard to be the human homologue of the presupplementary motor area (pre-SMA) was particularly active for learning of new sequential procedures (either position or color sequences), not movements per se. 3. In contrast, the SMA proper (posterior to pre-SMA) was active for the performance of sequential movements, not learning. This was shown in another paradigm in which the subjects pressed the buttons in any order in the test scans and just watched the sequence in the control scans. 4. The learning-related pre-SMA region, which was consistent across different experiments in single subjects, was identified on only one side in each subject.

Humans↗
PubMed1996

Leukopenia-inducing effect of a combination of a new 5-fluorouracil (5-FU)-derived drug, BOF-A2 (emitefur), with other 5-FU-derived drugs or BV-araU (sorivudine) in rats.

BOF-A2 (emitefur: 3-(3-[6-benzoyloxy-3-cyano-2-pyridyloxycarbonyl]benzoyl)-1-ethoxy- methyl-5- fluorouracil), a novel 5-FU (5-fluorouracil)-derived drug, was co-administered with other conventional 5-FU-derived drugs or BV-araU [sorivudine: 1-beta-D-arabinofuranosyl-(E)-5-(2-bromovinyluracil)] for 8 consecutive days to rats. BOF-A2 (6 or 8 mg/kg, p.o.) co-administered with other 5-FU-derived drugs elevated the plasma 5-FU concentration 3- to 23.3-fold and decreased the peripheral white blood cell (WBC). The percentage decreases of WBC by 5-FU (4 mg/kg, i.p.), UFT (16 mg/kg, p.o.), tegafur (FT; 16 mg/kg, p.o.), carmofur (HCFU; 15 mg/kg, p.o.), doxifluridine (5'-DFUR; 16 mg/kg, p.o.) and flucytosine (200 mg/kg, p.o.) were 25.7%, 31.9%, 70.3%, 32.0%, 58.6% and 30.0%, respectively, compared with each drug alone. On the other hand, these phenomena did not occur with BV-araU. These findings can be attributed to the fact that the inhibitory activity of CNDP (3-cyano-2,6-dihydroxypyridine) for 5-FU degradation (IC50: 6.3 x 10(-9) M) is potent and 6000 times greater than that of BVU [(E)-5-(2-bromovinyl) uracil], another inhibitor of 5-FU degradation.

Animals↗
PubMed1996

Hyaluronan and chondroitin sulfate in rabbit tears.

The concentrations of hyaluronan (HA) and chondroitin sulfate (CS) in rabbit tears were determined using high performance liquid chromatography. The tears were taken from both normal eyes and eyes with a corneal epithelial defect. The concentration of CS was 7.61 times higher than that of HA in the tears of normal eyes. When the concentration of CS isomers was compared, the highest concentration was observed in chondroitin 6-sulfate (C6S), followed by chondroitin 4-sulfate (C4S) and chondroitin (C0S), in that order. When the corneal epithelium was removed from the left eye using a trephine and microscissors, a significant increase was detected in the concentrations of HA and C6S in tears of the left eye one day after removal, whereas no change was observed in those of the right eye. In addition, a significant positive correlation was observed between the increased amount of HA concentration and the healing rate of the corneal epithelium. These results suggest that the increase of HA concentration in tears is associated with spontaneous corneal epithelial healing.

Animals↗
PubMed1996

Hyaluronan, CD44 and fibronectin in rabbit corneal epithelial wound healing.

Changes in hyaluronan (HA) concentration and stainability were investigated in the rabbit cornea after wounds made by exposure to n-heptanol. The HA concentration in the cornea increased gradually until day 14 after wounding, and then decreased. The HA concentration returned to the normal level 56 days after wounding. In the normal control cornea, HA staining was observed in the epithelium and stroma. The intensity of HA staining in the epithelium and stroma increased until day 3 after wounding, when the epithelium had completely covered the defect. At day 28, when the thickness of the corneal epithelium returned to the normal level, the intensity of HA staining in the epithelium also decreased. However, staining in the stroma was still strong. HA staining in the stroma decreased by day 56 after wounding. In parallel experiments, the immunostaining for CD44, an HA receptor, and fibronectin (FN) was carried out in the same model. The immunostaining in the epithelium of both CD44 and FN was synchronistic with the HA staining during the early stages after wounding. These events suggest that HA, CD44 and FN cooperatively play important roles in corneal epithelial wound healing.

Alcohols↗
PubMed1996

[Functional magnetic resonance imaging of the frontal eye fields during saccadic eye movements].

We evaluated activity-induced signal intensity changes in the human cerebral cortex during horizontal saccadic eye movements using functional magnetic resonance imaging (fMRI) based on the blood-oxygenation-level-dependent (BOLD) contrast method. Compared with central fixation, significant signal increases were observed bilaterally in the middle frontal gyrus (Brodmann area 8) during saccadic conditions. The location of the activated area was consistent with that of previously reported frontal eye fields (FEF). These results suggest that fMRI has potential merit for the study of cortical control of eye movements in humans.

Adult↗
PubMed1996

The combined antitumour effect of a new 5-fluorouracil derivative, BOF-A2, and radiation in vivo.

We examined the combined effect of radiation and BOF-A2, a newly developed anti-cancer agent consisting of a masked form of 5-fluorouracil (5-FU) and a potent inhibitor of 5-FU degradation in the liver, on murine tumors. Subcutaneous 8-mm-diameter SCCVII tumours grown in the right thigh of C3H/He mice were used. The mice were locally irradiated with single doses of 10-30 Gy or five fractions of 4 Gy for 5 days, alone or in combination with BOF-A2. BOF-A2 at doses of 30, 75 and 150 mg kg-1 was orally administered 2 h before or immediately after single doses of irradiation, while 15 or 30 mg kg-1 of BOF-A2 was given 1 h prior to each fraction of 4 Gy. The effect of BOF-A2 alone was also examined. The antitumour effect was evaluated by a tumour growth delay assay. BOF-A2 alone showed significant tumour growth delay at all doses used in this study. Combination of BOF-A2 and single or fractionated doses of radiation appeared to produce an additive tumour response, which occurred independently of sequence of the two treatments. The combined effect became greater with the dose of radiation and BOF-A2. In conclusion, BOF-A2 and radiation may be efficiently combined.

Animals↗
PubMed1996

[Levels of chondroitin 4-sulfate, chondroitin 6-sulfate and carboxy-terminal type II procollagen peptide in knee synovial fluid after injury to the anterior cruciate ligament].

Changes in the metabolism of articular cartilage associated with injury to the anterior cruciate ligament (ACL) is known to be one of the important factors for the progression to secondary osteoarthritis. To investigate the efficacy of biochemical markers for monitoring the cartilage metabolism after injury to ACL, we measured the levels of chondroitin 4-sulfate (C-4S), chondroitin 6-sulfate (C-6S) and carboxy-terminal type II procollagen peptide (pCOL II-C) in knee synovial fluid (SF) from the patients with ACL rupture and compared with those in knee osteoarthritis (OA). Within 10 days after ACL rupture, levels of C-6S and C-4S in SF were significantly higher than those in early stage of OA. Both levels decreased gradually and became to the same levels as those in early stage of OA at 30 days after the injury. In contrast, pCOL II-C levels in SF just after the injury were observed to be lower than those in early stage of OA. Then they increased gradually to the levels of those in early stage of OA at 30 days after the injury. High levels of C-6S and C-4S in SF just after ACL rupture seemed to reflect the increased release of matrix fragments caused by cartilage destruction associated with the injury. pCOL II-C levels in SF seemed to reflect the repairing process that increased slowly after the cartilage destruction. Measurement of these cartilage derived macromolecules in SF could be useful tools for monitoring the metabolism in articular cartilage after injury.

Adult↗
PubMed1995

Nucleosides and nucleotides. 141. Chemical stability of a new antitumor nucleoside, 2'-C-cyano-2'-deoxy-1-beta-D-arabino-pentofuranosylcytosine in alkaline medium: formation of 2'-C-cyano-2'-deoxy-1-beta-D-ribo-pentofuranosylcytosine and its antitumor activity.

We have designed 2'-C-cyano-2'-deoxy-1-beta-D-arabino- pentofuranosylcytosine (CNDAC) as a potential mechanism-based DNA-strand-breaking nucleoside, which showed potent tumor cell growth inhibitory activity against various human tumor cell lines in vitro and in vivo. When measuring the pKa of the 2' alpha-proton of CNDAC, we found that CNDAC epimerized to 2'-C-cyano-2'-deoxy-1-beta-D-ribo-pentofuranosylcytosine (CNDC) with concomitant degradation of both CNDAC and CNDC to cytosine and 1,4-anhydro-2-C-cyano-2-deoxy-D-erythro-pent-1- enitol. Kinetic analysis of these reactions showed that abstraction of the acidic 2'-proton of CNDAC and CNDC initiated the reactions, which quickly reached an equilibrium. In the equilibrium, a concentration ratio of CNDAC and CNDC was about 3:5. Concomitant degradation of these nucleosides was found to be rather slow. Deuterium incorporation experiments with CNDAC in a D2O buffer suggested the mechanism of the beta-elimination reactions is an E1cB type. These epimerization and degradation reactions were found even in neutral conditions (pH 7.5) and also occurred in RPMI 1640 cell culture medium. The discovery of which nucleoside possesses the predominate tumor cell growth inhibitory activity was important. While both nucleosides showed potent tumor cell growth inhibitory activity against three human tumor cell lines (colon carcinoma WiDr, small cell lung carcinoma SBC-5, and stomach carcinoma MKN-74 cells) in 48 h of incubation, in 20 min of incubation, CNDAC was 11-50 times more effective than CNDC. In vivo antileukemic activity of these nucleosides against a mouse P388 model, CNDAC was obviously superior to CNDC.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1995

Conductance change in phospholipid bilayer membrane by an electroneutral ionophore, monensin.

Monensin is a polyether antibiotic ionophore and is considered an electroneutral Na/H antiporter. Its addition, however, increased the conductance of phospholipid bilayer membrane, and this increase was observed only when the medium contained Na+. Analysis of the current-voltage curve suggested that the increase was due to the formation and the translocation of an univalently charged species. The conductance at zero external voltage was proportional to the second power of monensin concentration and increased with the decrease in pH of the medium. Modified monensin whose terminal carboxyl was esterified showed much larger increase (ca. 100 times) in conductance than intact monensin. We concluded that the complex between the dimer of protonated monensin and Na+ contributed to the electrogenic transport of monensin. This complex bears a +1 charge, which is consistent with the analysis of current-voltage curves. Contrary to the conductance, the Na+ transfer rate of liposomal membrane measured with 23Na-NMR was proportional to the monensin concentration, meaning that the electrogenic component contributes little to the total monensin-mediated Na+ transport in the present system. It should be noted that this electrogenic component may change the membrane potential.

Electric Conductivity↗
PubMed1995

The role of IL-4 and IL-6 in IL-1-dependent cartilage matrix degradation.

The objective of this paper was to study the effects of interleukin 4 (IL-4) and interleukin 6 (IL-6) on cartilage matrix degradation, the production of chondroitin-4-sulphate (C4S) and chondroitin-6-sulphate (C6S), metalloproteinase (stromelysin 1 = MMP-3) and metalloproteinase inhibitor (TIMP-1) production. Cartilage matrix degradation was assayed the release of 35SO4 from chondrocyte cultures. TIMP-1 and MMP-3 were measured by ELISA. C6S and C4S were measured by HPLC analysis. IL-1 beta significantly enhanced C4S production and significantly suppressed C6S production. Thus, the C4S/C6S ratio was significantly enhanced by IL-1 beta, and significantly suppressed by IL-4. IL-4 removed the suppressing effects of IL-1 beta for C6S and the enhancing effects of IL-1 beta for the C4S/C6S ratio. Whereas IL-1 beta stimulated the production of MMP-3, IL-4 and IL-6 had no effect on enzyme activity. IL-4, but not IL-6, removed the enhancing effects of IL-1 beta for MMP-3. In contrast, IL-4 and IL-6 significantly enhanced TIMP-1 production in chondrocytes, IL-4, but not IL-6, also significantly suppressed IL-1 beta-mediated cartilage matrix degradation. On the other hand, IL-6 significantly suppressed spontaneous cartilage matrix degradation which is supposed to be mediated by the autocrine IL-1 mechanisms. In conclusion our results suggest that IL-4 and IL-6 both protect the cartilage matrix degradation induced by IL-1.

Bone Matrix↗
PubMed1995

Lymphoepithelioma-like carcinoma originating on the eyelid.

An 89-year-old woman presented a rapidly growing red nodule of 5 years' duration on her left eyelid. Histologically, the entire dermis was occupied by multiple lobules of atypical tumor cell nests surrounded by inflammatory cells and fibrous stroma. The tumor cell nests were connected with the overlying epidermis and extended into the subcutaneous fat and muscles. There were no tendencies towards squamous or glandular differentiation of the tumor cells. Immunohistochemistry showed the tumor cells to be positive for keratin/cytokeratin and epithelial membrane antigen, but negative for neuron specific enolase and vasoactive intestinal polypeptide. S-100 protein-positive Langerhans cells were also found within the tumor nests. There was no apparent evidence of a primary lesion elsewhere.

Aged↗
PubMed1995

Proliferating activity of dermal fibroblasts in keloids and hypertrophic scars.

Monoclonal antibodies were used to demonstrate proliferating cell nuclear antigen (PCNA) and Ki-67 antigen of dermal fibroblasts in formalin-fixed, paraffin-embedded tissue sections of keloids, hypertrophic scars and normal skin. PCNA-stained fibroblasts were more pronounced than Ki-67, which showed only scanty Ki-67-positive fibroblasts. The mean density of dermal fibroblasts was significantly higher in keloids and hypertrophic scars than in normal skin (p < 0.01). The proliferating activity of fibroblasts detected by PCNA was significantly higher in keloids than in hypertrophic scars or normal skin (p < 0.01). The mean densities and the proliferating activities were apparently not correlated with the age of the patient. This indicates that keloids, with higher density and proliferating activity of dermal fibroblasts, continue to increase their volume and invade the surrounding tissue, while hypertrophic scars, with higher density and lower proliferating activity, show a tendency towards spontaneous regression.

Adolescent↗