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Biomedical subjects

H Hosoda

Publications and source records attributed to H Hosoda.

At least 73 records · Page 4Linked to original sources
PubMed1991

Effects of high-speed cutting on dentin permeability and bonding.

The effects of high-speed cutting by use of a diamond bur with or without water coolant or sanding by 80-grit SiC paper on dentin permeability, before and after surface treatment, and dentin bonding of adhesive resins were compared. Three different bonding systems were used: Scotchbond DC, which requires no removal of smear layers, and two others, Clearfil Photobond and Superbond C&B, both of which remove smear layers (phosphoric acid gel or 10% citric acid containing 3% ferric chloride, respectively). Creation of smear layers by bur cutting or sanding reduced dentin permeability to levels that were only 1-3% of the maximum permeability values. Scotchbond DC gave low but consistent bond strengths (3.7-6.1 MPa) to dentin covered with smear layers. Clearfil PHotobond also produced consistent bond strengths (8.6-9.4 MPa). The increase in the permeability of dentin after phosphoric acid treatment was higher when the SiC paper was used (146%) than when the high-speed bur was used (87-90%). The smear layer and smear plugs produced by the diamond bur were more resistant to 10-3 treatment than were the SiC-created smear layers. The bond strengths of Superbond showed the highest bond strengths to the conditioned dentin when the high-speed cutting was used with water coolant (16.3 MPa), compared with the other two groups (12.2-12.5 MPa).

Analysis of Variance↗
PubMed1991

Enzyme labeling in steroid enzyme immunoassays. Comparison of the p-nitrophenyl ester and N-succinimidyl ester methods.

Enzyme labeling of steroids by the p-nitrophenyl ester method was investigated in comparison with the N-succinimidyl ester method. The active ester of a testosterone or 11-deoxycortisol derivative was treated with beta-galactosidase and horseradish peroxidase to give labeled antigens. Various molar ratios of steroid to enzyme and pH conditions were tested. Satisfactory immunoreactivities with an anti-steroid antibody in each enzyme immunoassay system were obtained with the labeled antigens prepared at pH 8.5 by the use of molar ratios higher than 30. The enzyme labeling method should be useful in the case of polar steroids or drugs, since the p-nitrophenyl ester is relatively stable when compared with the N-succinimidyl ester.

Esters↗
PubMed1991

Chemical conversion of corticosteroids to 3 alpha,5 alpha-tetrahydro derivatives. Synthesis of 5 alpha-cortol 3-glucuronides and 5 alpha-cortolone 3-glucuronides.

The synthesis of the 3-glucuronides of 5 alpha-cortol-20 alpha, 5 alpha-cortolone-20 alpha and their 20 beta-epimers is described. The 5 alpha-cortol 20,21-diacetates (12, 17) and 5 alpha-cortolone 20,21-diacetates (14, 19) were the key intermediates. Sodium borohydride reduction of the carbonyl group at C-20 in 5 alpha-tetrahydrocortisol 3-tert-butyldimethylsilyl ether 17,21-acetonide (8) gave the 20 alpha-hydroxy-acetonide (9). Selective removal of the acetonide ring was successful when the 20 alpha-acetoxy-17 alpha,21-acetonide (10) was treated with 50% acetic acid. Subsequent acetylation with acetic anhydride in pyridine, followed by removal of the protecting group at C-3 in the silyl ether-acetate (11) gave the desired 20 alpha-intermediate (12). The 11-ketone (14) was prepared from 11 by oxidation with pyridinium chlorochromate, followed by desilylation. The 20 beta-acetates (17, 19) were synthesized from 21-acetoxy-3 alpha,11 beta,17 alpha-trihydroxy-5 alpha-pregnan-20-one 3-tert-butyldimethylsilyl ether (15). Introduction of the glucuronyl residue at C-3 was carried out by means of the Koenigs-Knorr reaction.

Adrenal Cortex Hormones↗
PubMed1991

Pulpal responses to various dentin bonding systems in dentin cavities.

The purpose of this study was to investigate pulpal response and bacterial invasion associated with five dentin bonding systems placed in cavities without an enamel margin. Two hundred and twenty-four dentin margin cavities were created by removing the surrounding marginal enamel of class V cavities in monkey teeth. These cavities were restored with a resin composite using various current dentin bonding systems. All of the dentin bonding systems showed odontoblastic layer changes to varying degrees, and slight to moderate inflammation at the initial stage. With the lapse of time, the degree of inflammation tended to decrease markedly, except for those cases in which bacteria were present. The result of SA/Photo Bond corresponded to that of the glass ionomer cement (negative control). Accordingly, this study suggests that a good bond and adaptation between resin and dentin should be obtained for eliminating pulpal irritation, even in the dentin cavity.

Animals↗
PubMed1990

[Mass screening for uterine cancer during the last 10 years--its present situation and problems].

In Omagari city and five towns, 37,793 women were subjected to mass screening of uterine carcinoma from 1979 to 1988. The detection rate of uterine carcinoma was 0.058%. Initial screening rate was 41% 10 years ago, but in 1988, it was decreased to 18%. The peak age of the mass screening was 50-54 years old, but the carcinoma and dysplasia high degree were detected mostly in patients aged 60 years old or more. And the constitution of the age of mass screening in this study was inadequate for the screening of endometrial carcinoma. It is important to emphasize that older women (aged 60 or above) and nullipara should be encouraged to actively participate in the screening of cervical and endometrial carcinoma.

Adult↗
PubMed1990

SEM and elemental analysis of composite resins.

Twenty-four chemically cured, 21 light-cured anterior, three light-cured anterior/posterior, and 18 light-cured posterior composite resins were examined using scanning electron microscopy, and the elemental composition of their filler particles was analyzed with an energy dispersive electron probe microanalyzer. According to the results obtained, the composite resins were divided into five groups (traditional, microfilled type, submicrofilled type, hybrid type, and semihybrid), with two additional hypothetical categories (microfilled and hybrid). Characteristics of each type were described with clinical indications for selective guidance of respective composite resins for clinical use.

Aluminum↗
PubMed1990

Chemical conversion of corticosteroids to 3 alpha,5 alpha-tetrahydro derivatives. Synthesis of allotetrahydrocortisol glucuronides and allotetrahydrocortisone glucuronides.

The synthesis of the 3- and 21-glucuronides of allotetrahydrocortisol (allo-THF) and allotetrahydrocortisone (allo-THE) is described. 5 alpha-Dihydrocortisol (5) was prepared by selective hydrogenation of 21-acetoxy-3, 11 beta, 17 alpha-trihydroxy-3,5-pregnadien-20-one 3-ethyl ether (3), followed by acid hydrolysis and saponification. When 5 alpha-dihydrocortisol 21-tetrahydropyranyl ether (6) was treated with potassium tri-sec-butylborohydride in tetrahydrofuran under mild conditions, regioselective and stereoselective reduction at C-3 took place to give allo-THF 21-tetrahydropyranyl either (7). This compound was converted into the 3- and 21-monoacetates of allo-THF and allo-THE, key intermediates. Introduction of the glucuronyl residue at C-3 or C-21 was carried out by means of the Koenigs-Knorr reaction. Prior to saponification yielding the 3-glucuronides (20,23), the alkali-sensitive ketol side chain at C-17 was protected as 20-semicarbazones.

Adrenal Cortex Hormones↗
PubMed1990

[Study on dental cements. 1. The cored structure of three luting cements obtained by using Cryo-SEM and image analyzer].

The polished surfaces of three set dental cements for luting (zinc phosphate cement, polycarboxylate cement, and glass ionomer cement) were observed by cryo-SEM at a specimen temperature of -160 degrees C to prevent damage of the cement specimens and also the specimens were analyzed by EDX. Furthermore, the SEM composition images of the polished cement surface were transferred to an image analyzer to obtain the core/matrix area ratio of the set cements. 1. The polished surface of set dental cement could be clearly observed by cryo-SEM without damaging the cement specimens. 2. The image analyzer showed that the core/matrix area ratio of the zinc phosphate cement and the glass ionomer cement was approximately 2 to 8, whereas that of the polycarboxylate cement was approximately 3 to 7. 3. The elements detected in the zinc phosphate cement were Ca, Zn, Mg, Al, and P, in the polycarboxylate cement were Ca, Zn, Mg, Si, and Sr, and in the glass ionomer cement were Al and Si.

Glass Ionomer Cements↗
PubMed1990

[Classification and several mechanical properties of core composite resins].

According to the classification proposed by Hosoda, six core resins could be divided into two categories on the basis of the elemental composition and size distribution of filler particles by SEM observation and EDX analysis. Furthermore, several mechanical properties of the resins were determined. The following facts were found: Bell Feel Core, Clearfil Core, Clearfil PhotoCore, Core Max, and Core Max II resins were classified as a semihybrid resin, and Microrest Core resin as a hybrid type resin. The elements detected in the resins by the EDX were Si, Zr, Al, Ba and La. The mechanical properties of the resins were shown to be highly stable at one day or one week after curing. The mechanical properties of the resins suggest that the subsequent crown preparation and impression taking should be postponed until the next appointment.

Composite Resins↗
PubMed1990

[Effect of various pretreatments for dentin bonding on dentin permeability].

Pretreatment of the dentinal surface with acidic solution is now considered to be necessary to obtain strong bonding between dentin and resin materials. Effects of various surface treatments for dentin bonding on dentinal smear removal have been reported by SEM observation. In this study, changes of dentin permeability after the surface treatments were measured using Pashley's technique. Forty-second treatments with either phosphoric acid gel, aqueous phosphoric acid, 10-3 solution or aqueous 10-20 Ca solution (10% citric acid containing 20% CaCl2) produced greater increases in dentin permeability compared with the treatments using either 10-20 Ca gel, Tenure Conditioner, Scotchprep or Gluma 2 for 40 seconds. Treatments with primers including adhesive monomers such as Scotchprep and Mirage Conditioner also increased the dentin permeability by removal of the smear layers and smear plugs. Application of a bonding agent (Clearfil Photobond) for 1 minute did not remove the smear plugs and the dentin permeability remained the same as before the treatment. The changes in dentin permeability were not predictable by SEM observation in some cases.

Acid Etching, Dental↗
PubMed1990

[In vivo wear test for posterior composites. 1. Development of wear test predicting composite wear in vivo].

A wear test method based on a new concept was developed for predicting the wear rate of posterior composite restorations in vivo. The concept based on the conclusions derived from our clinical tests on posterior composites that composite restorations would be deteriorated chemically and by repeated compressive stress as well as by abrasion by food passing during mastication. New wear tests were performed on several posterior restorative materials under various conditions to compare the effect of abrasion using the tooth-brush. The results of wear rate using the present test on specimens stored in a 0.1 N-NaOH solution (37 degrees C) for 6 days were parallel to those measured in clinical tests. However, the abrasion test results obtained using a tooth-brush on deteriorated specimens did not match the clinical data. These findings suggested that degradation or aging of specimens and repeated compressive stress are necessary for the wear test to simulate the wear of posterior composites in vivo.

Composite Resins↗
PubMed1989

The addition of an adhesive composite resin to the same material: bond strength and clinical techniques.

The addition of a chemically adhesive composite resin to a restoration of the same material may be evaluated by the bond strength. This was determined after no contamination and after momentary (30 seconds), short-term (7 days), and long-term (3 months) contamination under various conditions. The momentary contamination was not removed by spray-washing the glossy surface that set under a matrix. Removing the glossy surface reduced the bond. The momentary contamination was removed by the etchant whereas the longer contamination was removed only by surface reduction. The application of etchant and bonding agents significantly strengthened the bond to the reduced surface. According to the directives drawn from this investigation, the clinical techniques were illustrated for a large restoration, a subgingival proximal restoration, repair of an open proximal contact, and repair of a worn restoration.

Composite Resins↗
PubMed1989

Sensitivity of steroid enzyme immunoassays. Comparison of four label enzymes in an assay system using a monoclonal anti-steroid antibody.

The sensitivities of monoclonal antibody-based enzyme immunoassays for 11-deoxycortisol using alkaline phosphatase (AP), horseradish peroxidase (HRP), beta-galactosidase (beta-GAL) and glucose oxidase (GOD) as labels were compared. The anti-11-deoxycortisol antibody used was that produced in ascites by inoculating antibody-secreting hybridoma cells into mice. Enzyme labeling of 11-deoxycortisol was carried out by the N-succinimidyl ester method. The activated ester of 4-(2-carboxyethylthio)-11-deoxycortisol was treated with each enzyme to give a homologous enzyme-labeled antigen. In the competitive immunoassay, the bound and free enzyme-labeled antigens were separated by a double antibody method and the enzymic activity of the immune precipitate was determined by colorimetric and fluorimetric methods. The AP activity was measured in three ways, using p-nitrophenyl phosphate, nicotinamide adenine dinucleotide phosphate (NADP), and 4-methylumbelliferyl phosphate as substrates. o-Nitrophenyl beta-D-galactopyranoside and 4-methylumbelliferyl beta-D-galactopyranoside were used for beta-GAL, and 3,3',5,5'-tetramethylbenzidine (TMB) and 3-(p-hydroxyphenyl)propionic acid (HPPA) for HRP. In the case of GOD, TMB and HPPA were used in combination with HRP. A dose-response curve with a high sensitivity was obtained in each 11-deoxycortisol assay system by the use of a minimum amount of the enzyme-labeled antigen at an appropriate dilution of monoclonal anti-11-deoxycortisol antibody (Ka = 2 x 10(10) M-1). The amounts of 11-deoxycortisol needed to displace 50% of the bound label ranged from 5 to 15 pg in the colorimetric methods, and 4-9 pg in the fluorimetric methods.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMed1989

[Several properties of a newly developed light-cured anterior restorative composite resin "Graft LC"].

A newly developed light-cured anterior restorative composite resin "Graft LC" by GC Co. is characterized by having Vita VMK 68 shades and containing glass filler particles treated with graft binders. Several properties of the resin were examined by using the SEM, surface recorder, and color analyzer. The Graft LC resin was classified as semi-hybrid resin. The filler particles of Graft LC resin comprised two kinds of glass filler in which Si, Ba and Al, and Si were detected. Graft LC resin showed a relatively small surface roughness after polishing in spite of the semi-hybrid resin. According to the degradation test in the alkaline solution, the polished surfaces of Graft LC resin became rough and the depth of subsurface damage layer increased with time. However, the filler particles were retained in the subsurface damage layers. An Ar ion etching employed for SEM preparation is useful to observe the subsurface damage layer distinctly under the SEM. No color change was found even after long-term immersion in a distilled water, though the color of Graft LC resin changed greatly due to irradiation.

Biodegradation, Environmental↗
PubMed1989

[Finishing and polishing of composite resins. The experimentally designed silicone cup hards and their polishing ability].

To establish the most efficient polishing technique for composite resins, four kinds of silicone cup hards were experimentally designed, and the surface texture of two semihybrid composite resins polished with these experimental polishing tools were examined using a surface roughness recorder and by SEM. The individual silicone cup hard consisted of a hard rubber and silicone carbide abrasive particles being sized into #180 (P0), #360 (P2), #600 (P3), and #2500 (P4), respectively. Combination polishing with both P3 and P4, as well as from P0 through P4 in this order, efficiently created the smoothest surfaces for the semihybrid composite resins, which are generally considered to be hard to polish in the routine clinic.

Composite Resins↗
PubMed1989

[Establishment of a composite resin inlay technique. Part 1. The effects of various curing modes on mechanical properties of composite resins].

The effects of the curing mode on mechanical properties of composite resins were examined. Four resins as inlay, and three chemically-cured and five visible light-cured restorative resins were employed. The resin specimens were prepared by three kinds of curing modes; regular setting (according to the manufacturer's instruction), subsequently added light and heat curing after regular setting, and subsequently added heat and pressure curing after regular setting. Knoop hardness, flexure strength, compressive strength, and diametral tensile strength were determined. All restorative composites were remarkably increased in knoop hardness number due to the subsequently added curing methods. Both subsequently added curing methods provided higher flexure strength to all restorative resins, and particularly in the chemically-cured resins the flexure strength provided by the subsequently added light and heat curing was higher than those by the subsequently added heat and pressure curing. Compressive strength and diametral tensile strength were slightly increased by the subsequently added curing methods with the restorative resins. No correlation was found between the filler distribution and the mechanical properties provided by the subsequently added curing methods. The subsequently added heat curing seems to be preferable for creating higher mechanical properties of resins. The IC-2 resin, experimentally designed for resin inlay, seems to be the most promising resin for inlay restoration, based on the mechanical properties, and further detailed laboratory and clinical researches are required.

Composite Resins↗
PubMed1989

[Multidisciplinary treatment of head and neck cancer].

UNLABELLED: This presentation deals with multidisciplinary treatment of head and neck cancer, especially focusing on maxillary sinus carcinoma (MSC) and nasopharyngeal carcinoma (NPC). Since 1982, a new multidisciplinary treatment incorporating neo-adjuvant chemotherapy has been introduced in the treatment of MSC. The Neo-adjuvant chemotherapy includes cisplatin (CDDP) + peplomycin (PEP), adriamycin (ADR) analogs + CDDP + PEP, and CDDP +5-FU. Two courses of chemotherapy were given intraarterially with the interval of 2 weeks. Routinely, radiotherapy of 40 Gy by Linac was given to the primary tumor site, concomitantly combined with 5-FU intraarterial injections only during the first 10 days, 2 weeks after the end of chemotherapy. Additional treatment was performed according to the extent of the residual tumors. The 5-year survival rate for the 28 patients treated with this therapy was 55%. The 5-year survival rate by T classification was 100% for T2, 76% for T3 and 0% for T4 cases. The preservation rate of maxillo-facial structures and functions was 82%. Concerning NPC, neo-adjuvant chemotherapy included CDDP + PEP, ADR + CDDP + PEP and ADR + cyclophosphamide + PEP. Two courses of chemotherapy were performed, followed by radiotherapy of 60 Gy by Linac. Then intracavitary 60Co therapy was performed, followed by adjuvant chemoimmunotherapy. The 5-year survival rate for 21 patients treated with this therapy was 44%. CONCLUSIONS: (1) The 5-year survival rate was better for patients with MSC who were treated with multidisciplinary treatment incorporating intraarterial neo-adjuvant chemotherapy than that for patients who received other treatment so far. Furthermore, the highest preservation rate of maxillo-facial structures and functions was achieved in the neo-adjuvant chemotherapy group. However, survival rates for T4 cases were very poor, so another approach should be taken. (2) The 5-year survival rate was also better for patients with NPC who were given multidisciplinary treatment than for patients who received other treatment to date. However, there was no decrease of distant metastases, which we aimed initially, despite the introduction of neo-adjuvant chemotherapy.

Adult↗