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Biomedical subjects

T Ochi

Publications and source records attributed to T Ochi.

At least 271 records · Page 15Linked to original sources
PubMed1989

Repair of rabbit articular surfaces with allograft chondrocytes embedded in collagen gel.

In an attempt to repair articular cartilage, allograft articular chondrocytes embedded in collagen gel, were transplanted into full-thickness defects in rabbit articular cartilage. Twenty-four weeks after the transplantation, the defects were filled with hyaline cartilage, specifically synthesising Type II collagen. These chondrocytes were autoradiographically proven to have originated from the transplanted grafts. Assessed histologically the success rate was about 80%, a marked improvement over the results reported in previous studies on chondrocyte transplantation without collagen gel. By contrast, the defects without chondrocyte transplantation healed with fibrocartilage. Immunological enhancement induced by transplanted allogenic chondrocytes or collagen was not significant at eight weeks after treatment, so far as shown by both direct and indirect blastformation reactions. Thus, allogenic transplantation of isolated chondrocytes embedded in collagen gel appears to be one of the most promising methods for the restoration of articular cartilage.

Animals↗
PubMed1989

Active oxygen contributes to the major part of chromosomal aberrations in V79 Chinese hamster cells exposed to N-hydroxy-2-naphthylamine.

N-hydroxy-2-naphthylamine (NOH-2NA), an active metabolite of human occupational bladder carcinogens, induced, in V79 Chinese hamster cells, chromosomal aberrations which were suppressed in the presence of catalase and/or superoxide dismutase. The induction of the aberrations was more efficient in a more basic pH in parallel with the generation of hydrogen peroxide from NOH-2NA. The possible role of the oxidation product of NOH-2NA in the induction of the aberrations is discussed.

2-Naphthylamine↗
PubMed1989

A new intraocular lens formula for high myopia.

We developed a formula suitable for calculating intraocular lens power for eyes with axial lengths of 27 mm or greater. We then used this formula in a prospective study to determine its reliability in 32 eyes. In these latter cases the mean error between predictive postoperative refraction and actual postoperative refraction was 0.36 D, with 67% of the cases having less than 1.0 D error; 84% of the cases having less than a 2.0 D error; and no cases having an error greater than 3.0 D. The new formula provided greater accuracy for these highly myopic eyes than the SRK, SRKII, Hollady, and Thompson formulas.

Adolescent↗
PubMed1989

Elevated activity of myeloid growth factor in bone marrow adjacent to joints affected by rheumatoid arthritis.

Myeloid growth activity of rheumatoid arthritis (RA) and normal serum was measured with a newly developed simple method. Abnormally high titers of this activity were found in the bone marrow blood serum adjacent to joints with RA where abnormal myelopoiesis had been found. Maximal activity for myeloid growth was found at a molecular weight of 70 kDa in gel filtration of serum, different from the size of any known factors involved with myelopoiesis.

Adult↗
PubMed1989

[Repair of rabbit articular surfaces with allografts of chondrocytes embedded in collagen gels].

In an attempt to restore articular cartilage, allogeneic articular chondrocytes embedded in collagen gels were transplanted onto full-thickness defects in rabbit articular cartilage. Within 24 weeks after the transplantation, the defects were filled with hyaline cartilage, specifically synthesizing type II collagen. These chondrocytes were autoradiographically proven to be originated from the originally transplanted chondrocytes. As histologically assessed, success rate was about 80%, a marked improvement over the results (40% success rate) in previous studies reporting chondrocyte transplantation without collagen gels. On the other hand, the defects without chondrocyte transplantation healed with fibrocartilaginous tissue more than 24 weeks after treatment. Immunological enhancement induced by transplanted allogeneic chondrocytes or collagen was not significant for eight weeks after treatment, so far as shown by both direct and indirect blastformation reactions. Thus, allogeneic transplantation of isolated chondrocytes embedded in collagen gels appears to be one of the most promising methods for the restoration of articular cartilage.

Animals↗
PubMed1989

[Reversibility of glaucomatous defects of the central visual field].

We analyzed more than 4 consecutive measurements of the central area of the visual field in 1,004 eyes of 533 subjects with various types of glaucoma as diagnosed by the Octopus 201 and its examination program No. 31. We used a non-repeated analysis of variance to determine the statistical relationship between the mean sensitivity measurements for individual quadrants of the central visual field. We made the series of measurements used in this statistical analysis during repeated examinations that took place over a follow-up period of 1 year. Out of 1,004 eyes, 53 eyes (5.3%) were shown to have an improved mean sensitivity of the central 30 degrees of the visual field. We adopted the degree of sensitivity improvement [(final mean sensitivity - initial mean sensitivity)/follow-up period] as the indicator of the degree of reversibility in the central visual field to determine which factors might influence changes in the visual field. In patients under 50 years of age, who were at an early stage of the disease, as opposed to those over 50 years of age, who were at an intermediate or advanced stage of this disease or who had undergone reduction of intraocular pressure, a relatively high degree of sensitivity improvement was more frequently observed. In the cases with primary open angle glaucoma which includes low tension glaucoma, we think treatment for abnormality in the aqueous humor dynamics is very important. We concluded, that the reversibility of the central visual field defect in glaucomatous eyes is possible, though it can only be clearly detected by careful follow-up examinations employing computerized perimetry.

Female↗
PubMed1988

Natural course of joint destruction and fluctuation of serum C1q levels in patients with rheumatoid arthritis.

Using the number of joints with erosion in a total of 68 joints throughout the body, we studied a population of patients with rheumatoid arthritis whose disease duration was 10-15 years. Three groups, each showing a Poisson distribution, were found: the subset with least erosive disease (LES), the subset with more erosive disease (MES), and the subset with mutilating disease (MUD). The mean number of joints with erosion was 10.9 in LES, 32.2 in MES, and 53.5 in MUD. In LES, erosive articular changes were primarily limited to the peripheral smaller joints. In MES, the larger axial joints were also involved. Almost all joints were extensively damaged in MUD. During the early period of disease, differences between the 3 groups were highly significant in the rapidity of carpal bone destruction, as assessed by the yearly reduction of carpal height ratio (P less than 0.001), and in the serum C1q level (P less than 0.001).

Adult↗
PubMed1988

Differences in composition of sweat induced by thermal exposure and by running exercise.

To determine the differences in sweat composition between sweat induced by thermal stress alone and that induced by physical exercise, seven young healthy men first sat in a hot room and then performed running exercise. A 20-minute stay in a climate chamber at 40 degrees C resulted in a 5% reduction in body weight. The same body weight loss was induced by running exercise. Both sodium and chloride concentrations were much lower in the sweat induced by thermal exposure than that induced by the running exercise (p less than 0.01), while urea nitrogen and creatinine concentrations were significantly higher after thermal exposure than after the running exercise (p less than 0.01). Potassium concentrations did not differ significantly with either procedure. These findings suggest that sweat composition varies with the kind of induction and that more salt seems to be lost through exercise-induced sweating than by just sitting in a hot environment.

Adult↗
PubMed1988

Glutathione and metallothioneins as cellular defense against cadmium toxicity in cultured Chinese hamster cells.

To evaluate the protective role of cell glutathione (GSH) against the toxicity of cadmium, the effect of GSH depletion on the metal toxicity was investigated and the role of glutathione was compared with that of zinc-induced metallothioneins (MTs). A 6-h incubation of cultured Chinese hamster V79 cells with 0.2 mM L-buthionine-SR-sulfoximine (BSO), a selective inhibitor of gamma-glutamylcysteine synthetase, resulted in approx. 95% depletion of GSH in the cells. The depletion of GSH did not influence the rate of cell growth, the amount of cell protein or the chromosome structure during culture for at least 24 h. Cells depleted or not depleted of GSH were challenged with (1-5).10(-5) M CdCl2 for 2 h and subsequent cell growth was evaluated. The cytotoxicity of cadmium was enhanced with increasing duration of BSO pretreatment and was correlated with the decrease of cell GSH, indicating that GSH constitutes a cellular defense against toxicity by cadmium. Inducibility of MTs by zinc was investigated in cultured V79 cells. Incubation of the cells with 1.10(-4) M zinc acetate did not result in accumulation of MTs over the control values for up to 2 h. Thereafter, however, the synthesis of MTs increased with increasing duration of zinc treatment and an approx. 9-fold increase in the amount of MTs was observed 10 h after addition of zinc. Depletion of cell GSH by BSO did not much influence the increased accumulation of MTs by zinc. In contrast, zinc at the same concentration did not influence the level of cell glutathione up to 12 h. The cytotoxicity of cadmium was markedly reduced in the cells pretreated with zinc and the protective effect of zinc was dependent upon duration of pretreatment, being parallel with the increased accumulation of MTs. Protection of cells from cadmium toxicity by zinc pretreatment was as or a little more effective in the cells depleted of GSH as in those not depleted. Thus, glutathione appears to be an intrinsic protector against cadmium toxicity, while MTs serve as an induced cellular defense that is mobilized against heavy metal stress, but takes more than 2 h to accumulate in significant amounts. Accordingly, it is suggested that GSH and MTs have cooperative protective roles against cadmium toxicity, as an initial defense for the former and a second-stage defense for the latter.

Acetates↗
PubMed1988

Effects of glutathione depletion and induction of metallothioneins on the cytotoxicity of an organic hydroperoxide in cultured mammalian cells.

The effects of glutathione depletion and induction of metallothioneins (MTs) on the cytotoxicity of t-butyl hydroperoxide (t-BHP) were investigated in cultured Chinese hamster V79 cells. The cytotoxicity of t-BHP was enhanced with increasing duration of the pretreatment with L-buthionine-SR-sulfoximine (BSO), a selective inhibitor of gamma-glutamylcysteine synthetase, and was correlated with the decrease of cell glutathione, indicating that glutathione constitutes a cellular defense against toxicity by t-BHP. Desferrioxamine, a specific iron chelator, suppressed partly inhibition of cell growth induced by t-BHP and suppressed completely the increase of the cytotoxicity caused by glutathione depletion. Butylated hydroxytoluene, a diffusible radical scavenger, showed almost the same suppressive effect as desferrioxamine. These results suggest that the cytotoxicity of t-BHP enhanced by the depletion of glutathione is attributable to an action of iron-mediated reactive radical species. Pretreatment with zinc (10(-4) M) suppressed the cytotoxicity of t-BHP that was enhanced by depletion of glutathione and the extent of suppression was paralleled with increasing duration of zinc pretreatment that correlated with increased synthesis of metallothioneins (MTs). Maximum induction of MTs also suppressed the t-BHP-induced inhibition of cell growth at 4 degrees C in glutathione-depleted cells. These results suggest that MTs act as a scavenger for the reactive radical species which are formed in an iron-mediated manner.

Animals↗
PubMed1988

Intraocular lens implantation and high myopia.

We evaluated aphakia and pseudophakia in highly myopic patients whose axial lengths were 27 mm and over. Cataract surgery alone was performed on 99 eyes (aphakic group) and intraocular lens (IOL) implantation was performed on 84 eyes (pseudophakic group). The IOL power was determined by the SRK formula and ranged from +9.0 to +18.5 diopters (D). There was no statistical difference in postoperative complications between the aphakic and pseudophakic groups. The postoperative aphakic refractions ranged from +9.5 D to -3.5 D, and the pseudophakic refractions, from +2.5 D to -14.0 D. A visual acuity of 20/40 or better was achieved by 51% of aphakic patients and 63% of pseudophakic patients. A near visual acuity of 20/40 or better was achieved by 65% of pseudophakic patients. Seventy-three pseudophakic eyes (87%) were not corrected or were corrected with minus diopter lenses. This confirmed our opinion that there was no need to correct them for near vision. According to a postoperative questionnaire, 67% of the pseudophakic patients did not need spectacles for near vision and 93% of patients could see comfortably for daily life. In view of these results, we feel that most myopic patients are good candidates for IOL implantation.

Adult↗
PubMed1988

The presence of a myeloid cell population showing strong reactivity with monoclonal antibody directed to difucosyl type 2 chain in epiphyseal bone marrow adjacent to joints affected with rheumatoid arthritis (RA) and its absence in the corresponding normal and non-RA bone marrow.

The presence of a specific type of cell, highly expressing difucosyl type 2 chain (dimeric Lex; FH-4 antigen), was found in the epiphyseal bone marrow cells of affected joints from patients with active severe rheumatoid arthritis (RA). The antigen was defined by monoclonal antibody FH-4 which was previously found to be directed to the oncofetal marker. The FH-4(+) cell population was identified as myeloid cell lineage with usual morphology specifically found in bone marrow of patients with severe RA, but is virtually absent in the same cell fraction of patients with osteoarthritis, infectious arthritis, and from normal adult subjects.

Adult↗
PubMed1987

Indirect evidence for the induction of a prooxidant state by cadmium chloride in cultured mammalian cells and a possible mechanism for the induction.

The effects of scavengers of active oxygen species on cadmium chloride (CdCl2)-induced inhibition of cell growth and DNA synthesis and on the metal-induced clastogenesis were investigated to evaluate whether cadmium could induce a prooxidant state in cultured Chinese hamster V79 cells. Inhibition by CdCl2 of cell growth and [3H]thymidine incorporation into the acid-insoluble fraction of cells and the metal-induced clastogenesis were suppressed in part by the presence of the diffusible radical scavenger, butylated hydroxytoluene (BHT). The action of BHT was concentration-dependent and did not affect the intracellular level of cadmium. D-Mannitol, a hydroxyl radical scavenger, also significantly suppressed Cd-induced inhibition of cell growth and [3H]thymidine incorporation. Catalase was marginally suppressive on Cd-induced inhibition of cell growth. These results suggest that cadmium can induce a prooxidant state in cultured mammalian cells. The mechanism by which cadmium induces a prooxidant state was investigated by measuring the effect of cadmium on those enzymes which constitute a cellular defense against active oxygen and on the level of the intracellular antioxidant, glutathione (GSH). 2-h treatments with CdCl2 over a concentration range of 2-10 X 10(-5) M did not influence superoxide dismutase, catalase, GSH peroxidase or GSSG reductase. In contrast, the level of glutathione was decreased to approximately 40% by treatment with 2 X 10(-5) M cadmium. The decrease in glutathione level may be responsible for a role by active oxygen in Cd-induced inhibition of cell growth and DNA synthesis and the metal-induced clastogenesis.

Animals↗
PubMed1987

Involvement of DNA polymerases in the repair of DNA damage by benzo[a]pyrene in cultured Chinese hamster cells.

Mechanisms for induction of single-strand scissions in DNA by S9-activated benzo[a]pyrene (B[a]P) and their repair in cultured Chinese hamster V79 cells were investigated with inhibitors of DNA-repair synthesis using alkaline sucrose gradient sedimentation analysis. The marked induction of single-strand scissions in DNA was observed following 3 h treatment of V79 cells with 5 micrograms/ml of B[a]P. These DNA lesions were repaired to the control level within 4 h after removal of B[a]P. The simultaneous addition of inhibitors of DNA-repair synthesis. 1-beta-D-arabinofuranosylcytosine (araC) plus hydroxyurea with B[a]P did not increase the formation of DNA single-strand scissions. When these inhibitors were added after removal of B[a]P, however, they significantly blocked the rejoining of DNA-strand scissions. On the other hand, when aphidicolin, a specific inhibitor of DNA polymerase alpha, was used instead of araC, a partial inhibition of the rejoining was observed, and further addition of 2',3'-dideoxythymidine, an inhibitor of DNA polymerase beta, augmented the inhibitory effect. These results indicate that B[a]P-induced single-strand scissions of DNA in V79 cells could be repaired mostly by excision repair which involved DNA polymerase alpha and a non-alpha polymerase, presumably polymerase beta.

Animals↗
PubMed1987

Clastogenic action of hydroperoxy-5,8,11,13-icosatetraenoic acids on the mouse embryo fibroblasts C3H/10T1/2.

Phorbol 12-myristate 13-acetate induces the release of a low molecular weight clastogenic factor from monocytes. Hydroperoxy-5,8,11,13-icosatetraenoic acids represent major components of clastogenic factor. We report that several isomeric hydroperoxy-5,8,11,13-icosatetraenoic acids efficiently induce DNA strand breakage and/or alkali-labile sites in the mouse embryo fibroblasts C3H/10T1/2. Fe chelation by desferrioxamine suppresses breakage by approximately equal to 42% indicating the participation of Fe-catalyzed radical reactions. An additional 37% inhibition is observed upon addition of the Ca2+ chelators EGTA and quin-2. This result suggests that hydroxyperoxy-5,8,11,13-icosatetraenoic acid may activate a Ca2+-dependent nuclease. The addition of the antioxidant enzymes CuZn-superoxide dismutase and catalase had no effect, while glutathione peroxidase suppressed strand breakage by 90%. To our knowledge, our results yield a first insight into the mechanism of action of monocyte clastogenic factor and the role of inflammation in tumor promotion.

Animals↗
PubMed1987

[Clinicopathological study of colorectal cancer in young adults including a case of cancer family syndrome].

During the last 6 years, we examined 402 cases (including 5 cases in their 20's and 17 cases in their 30's) of colorectal cancer. We compared three groups (cases in their 20's, cases in their 30's, and cases over 40 years old), and had the following results. Cases in their 20's had a higher rate of familial history of colorectal cancer, and the cancer was located mainly in the proximal colon. Well differentiated and moderately differentiated adenocarcinoma was dominant in the cases in their 30's and in those over 40 years old. On the other hand mucinous adenocarcinoma and signet ring cell carcinoma was dominant in the cases in their 20's. A case of cancer family syndrome is also presented.

Adenocarcinoma↗
PubMed1986

Induction of alkaline-labile sites in DNA by benzo [a]pyrene and the repair of those lesions in cultured Chinese hamster cells.

Formation of alkaline-labile sites in DNA by S9-activated benzo [a]pyrene (B [a]P) and the repair of those lesions were investigated using the technique of alkaline elution in cultured Chinese hamster V79 cells. When the cells were treated with B [a]P (1-5 micrograms/ml) there was negligible increase in DNA elution at pH 12.1 as compared to untreated controls. However, the elution of DNA increased at pH 12.6 with a concentration dependency, thereby indicating formation of alkaline-labile sites in DNA by B [a]P. After 4 h of repair incubation the elution of DNA at pH 12.6 of B [a]P (5 micrograms/ml) treated cells returned to the control levels. The half-life of alkaline-labile sites formed by B [a]P was approximately 1.5 h. Inhibitors of DNA-repair synthesis, hydroxyurea (HU) and 1-beta-D-arabinofuranosyl cytosine (ara-C) when added simultaneously with S9-activated B [a]P for 3 h showed an increase in elution of DNA at pH 12.1, indicating that a population of B [a]P-induced DNA lesions could be removed by a rapid DNA-repair process. These results indicate that at least two kinds of DNA lesions, repairable alkaline-labile sites and rapidly repairable DNA single-strand breaks, are detected after B [a]P treatment by the use of the alkaline elution procedure, by changing elution pH.

Animals↗