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Biomedical subjects

H Oguchi

Publications and source records attributed to H Oguchi.

At least 109 records · Page 6Linked to original sources
PubMed1990

Effects of a selective thromboxane synthetase inhibitor OKY-046 on experimental diabetic nephropathy.

To examine the effects of endogenous thromboxane A2 on the development of diabetic nephropathy, we administered OKY-046, an inhibitor of thromboxane synthesis, to streptozotocin-induced diabetic rats. Animals were divided into three groups; nondiabetic control, diabetic, and diabetic with OKY-046, and were sacrificed 16 weeks after experimental procedures. The chronic oral administration of OKY-046 to diabetic rats significantly decreased plasma and urinary thromboxane B2 levels. Urinary protein excretion and serum glucose levels were significantly lower in the OKY-046-treated diabetic rats than in the untreated diabetics (60.8 +/- 23.2 vs. 94.1 +/- 33.4 mg/day in the 16th week, p less than 0.05 and 424.4 +/- 93.3 vs. 614.4 +/- 102.3 mg/dl in the 16th week, p less than 0.01, respectively). Platelet aggregation was inhibited by OKY-046. Blood urea nitrogen was unaffected. Ultrastructural examination revealed that the thickness of glomerular basement membrane was markedly thinner in the OKY-046-treated diabetic rats than in the untreated diabetics (197.4 +/- 29.6 vs. 288.6 +/- 46.9 nm, p less than 0.01). These results suggest that thromboxane A2 may play an important role in the development and progression of diabetic nephropathy in rats.

6-Ketoprostaglandin F1 alpha↗
PubMed1990

Prevalence of anti-HCV in patients on long-term hemodialysis.

The prevalence of hepatitis C virus (HCV) infection in patients with long-term hemodialysis (HD) in Japan was assessed using an Ortho HCV Antibody ELISA TEST system. Out of 51 patients, 48 of whom had a history of blood transfusions, 15 (29%) were positive for anti-HCV. This figure is much higher than that in other countries (1-20%), and the difference may reflect a select population. Six (33%) of 18 HD patients with chronic hepatic disease were anti-HCV positive. On the other hand, the prevalence of hepatitis B virus (HBV) markers was 39% (20/51), and 7 (35%) of these 20 with HBV markers were also positive for HCV. The prevalence of anti-HCV showed no relation to the duration of HD treatment. Although a correlation between the prevalence and the blood units transfused was not demonstrated, anti-HCV positive patients had received blood transfusions amounting to significantly more units than those given to negative patients. Anti-HCV was detected in approximately one-third of patients with long-term HD, indicating a lower prevalence of HCV infection as compared to that of HBV infection, and patients with hepatitis of type C accounted for about one-third of HD patients with chronic hepatic disease.

Enzyme-Linked Immunosorbent Assay↗
PubMed1990

[Biochemical studies of three cases of a compound odontoma].

This study was conducted to investigate some biochemical characteristics of compound odontoma obtained from three cases, all found in the mandible. The results were compared with data obtained from deciduous teeth (3) and permanent teeth (3). The mole ratios of calcium to inorganic phosphorus (Ca/P) among three groups were deviated between 1.67 and 1.68 in the enamel extracts and between 1.65 and 1.69 in the dentine extracts. No significant differences were found in each case. Amino acid analysis of dentine showed apparent differences among these groups in the degrees of hydroxylation of proline (Hyp/Pro + Hyp) and of lysine (Hyl/Lys + Hyl). Hydroxylation rates of proline were 43.1 +/- 0.98% for the permanent teeth, 44.4 +/- 0.47% for the deciduous teeth and 40.9 +/- 0.44% for the odontoma. Hydroxylation rates of lysine were 32.0 +/- 0.67% for the permanent teeth, 27.3 +/- 0.0% for the deciduous teeth and 26.5 +/- 0.46% for the odontoma. T-test confirmed the significance of the differences between the permanent teeth and odontoma in the case of lysine (p less than 0.5%) and between the deciduous teeth and odontoma in the case of proline (p less than 0.5%). These results suggest the differential organization of dentine matrix between human permanent teeth, deciduous teeth and compound odontoma.

Dentin↗
PubMed1990

[A new technique for the treatment of ectopically erupting permanent first molars].

The problem and treatment of the ectopically erupting permanent first molars have been addressed by many authors since they were first mentioned in the literature by Chapman in 1923. Many treatments involve techniques using the primary second molar. It is better for correcting the eruption of the permanent first molar into normal occlusion to maintain the primary second molar in its normal position. However severe mobility and root resorption are often present when an ectopic eruption is found. An 8-year-old male with ectopic eruption of the maxillary right permanent first molar was examined and treated. The right primary second molar demonstrated severe mobility and root resorption, and therefore a new appliance using the primary first molar was designed. After 4 months from the beginning of the treatment the mobility of the primary second molar decreased, and after 6 months the permanent first molar almost erupted in its normal position.

Child↗
PubMed1990

[Quantitative evaluation by measuring affected area for cytotoxicity of dental materials].

The agar overlay method was modified and employed in this study to quantitatively evaluate the cytotoxicity of dental materials. The area of fibroblasts affected by the release of toxic substances from tested materials was determined with an image analysis system in order to compare the relative cytotoxicity of amalgams and composite resins. The cytotoxicity of amalgams decreased by 50% or more with aging time. Zinc appeared to be the major contributor to the cytotoxicity of amalgams. The cytotoxicity of chemically cured composite resins was also reduced with hardening time. However, even after 24 hours, the cytotoxicity of all chemically cured composite resins was still apparent. The cytotoxicity of light cured composite resins was dramatically reduced after illumination with the light source. The cytotoxicity of both amalgams and composite resins was strongly dependent upon their hardening process, since aging and curing produced a more stable material which was less likely to release toxic substances into the culture medium. The technique developed in the present study for measuring the area of affected cells to quantitatively evaluate the cytotoxicity of dental materials is simple and reproducible.

Composite Resins↗
PubMed1990

[Pulse oximetry for noninvasive oxygen monitoring during dental treatment in children with congenital heart disease].

Children with congenital heart disease (CHD) are prone to present abrupt changes in cardiovascular functions which cause hypoxic spells or acute heart failure, so that oxygen monitoring during dental treatment is of great importance in cyanotic CHD patients. Monitoring of arterial oxygen saturation (SpO2) by pulse oximetry has several advantages, including rapid response time, freedom from skin injury, self-calibration and continuous readout of the SpO2 value. In these studies, SpO2 was measured in 68 pediatric patients (55 were CHD children and 13 were normal children) during dental treatment at the Pediatric Dentistry, Hokkaido University Dental Hospital. In all of the normal patients, SpO2 did not desaturate less than 95%. On the other hand, SpO2 ranged from 56% to 98% in CHD patients, and in 22% (n = 12) of these, SpO2 desaturated below 80%. All of the SpO2 less than 80% patients had been diagnosed as cyanotic CHD. Classification of CHD cases (n = 144, the total number of measurements) on the pattern of the SpO2 variation revealed that in 11% (n = 16) of the CHD cases, SpO2 decreased during dental treatment. Twelve of these 16 cases could not readily accept dental treatment. We suggest that behavior management is the most important factor in CHD patients for keeping SpO2 stable. Motion artifact of the SpO2 value, which was easily evoked when a patient bent his elbow or shook his finger, often made the pulse oximetry useless. In our studies, the SpO2 value sometimes became inaccurate in fearful infants or handicapped patients. Pulse waveform displayed on the front panel of pulse oximetry was useful to identify the motion artifact. We conclude that pulse oximetry is an appropriate apparatus for continuous arterial oxygen monitoring in pediatric patients during dental treatment as far as motion artifact is effectively eliminated.

Artifacts↗
PubMed1990

Effect of lactose derivatives on metastatic potential of B16 melanoma cells.

The effects of various sugars and sugar derivatives on lung colonization (i.e., metastatic deposition) of the highly metastatic BL6 clone of B16 mouse melanoma cells in syngeneic mice were studied, based on the assumption that carbohydrate structures, particularly those with a Gal terminus, play a crucial role in defining the metastatic potential of B16 cells. After incubation with sugar compounds (usually at 0.1 M concentration), tumor cells were injected via the tail vein into 8-week old female mice. Mice were sacrificed after 18-21 days, and tumor cell colonies in lung were counted under a dissecting microscope. Only methyl beta-D-lactoside and lacto-N-tetraose caused significant reduction (35-45% and 36%, respectively) of metastatic deposition compared to controls. Methyl beta-D-lactoside did not exhibit a growth inhibitory effect on BL6 tumor cells, as determined by several methods: in vitro [3H]thymidine incorporation assay, in vitro plating in RPMI-1640 medium culture under physiological conditions followed by cell counting, and in vivo subcutaneous inoculation of age-matched C57/BL mice followed by tumor measurement. These results indicate that the inhibitory effect of methyl beta-D-lactoside on tumor deposition was not related to its effect on tumor cell growth.

Animals↗
PubMed1989

The role of oxygen free radicals in experimental acute pancreatitis in the rat.

In order to elucidate the role of oxygen-derived free radicals in acute pancreatitis, scavengers and an inhibitor of production of these free radicals were administered to rats with experimentally-induced acute pancreatitis. Acute reflux pancreatitis was produced by the occlusion of the common bile duct (OCD). Catalase and superoxide dismutase (SOD) were used as scavengers, and allopurinol was used as an inhibitor of production of free radicals. Six h after surgery, serum amylase, lipase, and thiobarbituric acid (TBA) reactant levels were elevated significantly, and histological changes in the pancreas, consisting of edema, inflammatory cell infiltration, and necrosis, partially around the intralobular and interlobular ducts, developed in the control rats receiving no agent. However, serum lipase and amylase levels in the rats given each agent were significantly lower (p less than 0.05) than in the controls. The histological changes in the pancreas were less marked in agent-treated rats than in untreated rats. These results suggest that oxygen-derived free radicals participate in the development of acute pancreatitis.

Acute Disease↗
PubMed1989

Allopurinol stimulates pancreatic exocrine secretion in the dog.

The effects of allopurinol on the secretion of pancreatic juice were investigated both in live animals and in preparations of isolated, blood-perfused dog pancreas and were compared with those of secretin. An i.v. administration of allopurinol (3-10 mg/kg) caused a dose-dependent increase in the pancreatic secretion. The secretory responses to 3 and 10 mg/kg of allopurinol were approximately equal to those to 0.03 and 0.1 U/kg of secretin, respectively. An intra-arterial (i.a.) infusion of allopurinol (0.5-1.2 mg/min) also elicited dose-dependent increases in flow rates, bicarbonate concentrations, and outputs of pancreatic exocrine secretion, but protein concentrations were little affected by allopurinol. Similar results were obtained in the juice induced by an i.a. infusion of secretin (0.012-0.05 U/min). Both bicarbonate and protein concentrations in the juice obtained with allopurinol were almost the same as those obtained with secretin at a similar flow rate of pancreatic secretion. The secretory activities at 0.5, 1.0, and 1.2 mg/min of i.a. allopurinol infusion corresponded roughly to those at 0.012, 0.025, and 0.05 U/min of i.a. secretin infusion, respectively. Therefore, the secretory action of allopurinol was similar to that of secretin. The allopurinol-induced secretion was not modified by pretreatment with atropine sulfate, cimetidine, or sulpiride hydrochloride. These results suggest that allopurinol stimulates pancreatic secretion by acting directly on ductular cells of the dog pancreas.

Allopurinol↗
PubMed1989

Studies on two siblings with recessive dystrophic epidermolysis bullosa (Hallopeau-Siemens) and the plasminogen activator and its inhibitor in the lesion.

Activities of plasminogen activators (PA) and their inhibitors were studied in the bullous lesions of 2 siblings with recessive dystrophic epidermolysis bullosa (RDEB). The hematological findings of the patients revealed hyperfibrinogenemia, hyper-gamma-globulinemia and marked thrombocytosis. The immunofluorescent studies showed strong deposits of plasminogen, fibrin-degenerative products and alpha 1-antitrypsin around the blister lesions. On the other hand, alpha 2-macroglobulin (alpha 2-M) was sparsely deposited. The levels of alpha 2-M in the blister fluid of the patients were also decreased in comparison with those from patients with other bullous dermatoses. The topical application of antibiotic ointment with strong PA inhibitor was clinically effective when applied to the blister and eroded lesions of the patients. These findings suggest that the increased activity of PA may play an important role in the development of blister formation in patients with RDEB.

Adolescent↗
PubMed1989

[Oxygen metabolism in roots resorbing granulated tissue from bovine deciduous teeth, from the aspects of superoxide dismutase, lactate dehydrogenase, and lipid peroxidation].

Root resorbing of deciduous teeth is a general phenomenon during eruption of the permanent teeth. In the present study, we tried to clarify the active-oxygen metabolism of root resorped granulated tissues. Granulated tissues were obtained from two fresh mandibles of young bovine about 1 year old undergoing root resorption. Cu-Zn-Superoxide dismutase (SOD), Mn-SOD, Lactate dehydrogenase (LDH), and concentration of lipid-peroxidated products were determined on the supernatants from homogenized tissues. We obtained the following results. 1) Cytosolic Cu-Zn-SOD activity did not elevate as compared to control tissues. 2) Elevation of mitochondrial Mn-SOD activity was observed in granulated tissues. 3) LDH activity did not elevate as compared to control tissues. 4) Lipid-peroxidated products in granulated tissues showed high concentration as compared to control tissues. Based on the above, we specurated that the active-oxygen metabolism in the root resorped granulated tissues, at least in mitochondria, was elevated.

Animals↗
PubMed1989

[Correlation between the illumination time and cytotoxicity of light-cured composite resins].

This study was undertaken to compare the relative cytotoxicity of light cured composite resins, and the cytotoxic reduction of light cured composite resins by illumination time by means of in vitro cell culture test. Light cured composite resins (P-30, Silux, Occlusin, Graft LC, Litefil A, Photo Clearfil A, Palfique light and Herculite XR) were filled into glass tubes (4 mm inner dia. x 1 mm high), then illuminated for 0, 10, 20, 30, 40, 50 and 60 seconds through a matrix strip with direct contact ot an Optilux light source (3M), just before testing. Fibroblasts, 2 ml of 1 x 10(5) cells/ml in Eagle's MEM medium supplemented with 10% FCS, penicillin (100 U/ml) and streptomycin (100 micrograms/ml) were evenly seeded on a cover glass in a tissue culture dish and incubated for 24 hours at 37 degrees C in a humidified atmosphere of 5% CO2 in the air. After 24 hours of incubation, the medium was replaced with 2 ml of agar overlay medium consisting of 10% FCS, Eagle's MEM medium and 1.5% agar. Glass tubes (N = 8) filled with the light cured composite resins were placed at the center of the agar, and incubated for 24 hours in 5% CO2 in air at 37 degrees C. After 24 hours of incubation, the cover glass was removed and the cells were fixed in a 10% neutral formalin, then stained with toluidine blue (pH = 9.3) to differentiate the areas of affected and unaffected cells beneath the test specimens. The affected area was quantitatively determined using an image analysis system. The results indicated that there was a high significant reduction in the cytotoxicity of any of the light cured composite resins except Palfique light when light was illuminated. All of the uncured light-cured composite resins revealed a high magnitude of cytotoxicity. However, when composite resin was illuminated, the cytotoxcity of the resin was dramatically reduced, and the longer the light illumination time became, the lesser the cytotoxicity was shown. Palfique light showed a much higher magnitude of cytotoxicity at any light illumination time than any other composite resins. heruclite XR showed less cytotoxicity than Palfique light, however at 60 seconds illumination the cytotoxicity was still shown. The cytotoxicity of composite resins was completely eliminated with illumination times of 50 seconds for P-30, and 60 seconds for Silux. The cytotoxicity of Graft LC, Occlusin and Photo Clearfil A was eliminated with 20 secondlight illumination which showed the least cytotoxicity among the light cured-composite resins tested.(ABSTRACT TRUNCATED AT 400 WORDS)

Cells, Cultured↗
PubMed1989

[Proliferation and superoxide dismutase (SOD) induction of Streptococcus mutans (sobrinus) B13. 1. Metal requirement].

Many of micro-organisms under aerobic conditions showed oxygen tolerance caused by the induction of several oxygen-derived free radical scavengers. In the present study, we tried to clarify the changes of active oxygen metabolism of streptococcus mutans (sobrinus) B13 under aerobic conditions. Aerobic and anaerobic culture of streptococcus mutans (sobrinus) B13 was made in normal, metal chleted, and metal supplemented medium. Superoxide dismutase (SOD) activity and bacterial proliferation were determined on the cultured cells. We obtained the following results. 1) In the anaerobic normal medium, SOD activity was not detected, but proliferation was observed. On the other hand, the neither were detected in the metal chleted medium. 2) No effect was observed on the induction of SOD activity and proliferation by the supplementation of copper in the metal chelated medium. 3) We observed positive effects on the induction of SOD activity and proliferation by the supplementation of iron, managnese, or both in the metal chlated medium under aerobic condition. Based on the above results, we found that iron and manganese were essential metals for SOD activity induction. Moreover, we suggested that there was close association of the aerobic bacterial proliferation with the induction of oxygen-derived free radical scavengers.

Energy Metabolism↗