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Biomedical subjects

T Kono

Publications and source records attributed to T Kono.

At least 145 records · Page 8Linked to original sources
PubMed1996

Effect of low-power laser irradiation on impulse conduction in anesthetized rabbits.

Low-power laser analgesic effect was generally accepted in clinical cases, whereas there was no direct evidence to indicate that low-power laser irradiation suppressed an impulse conduction within a peripheral nerve. The effect of low-power laser irradiation on electrically evoked responses within the sural nerve was electrophysiologically analyzed in anesthetized rabbits. High threshold evoked responses (conduction velocity was about 11 m/sec, unmyelinated A delta), which were induced by an electrical stimulation to the peripheral stump of the nerve, were significantly suppressed (9 to 19% inhibition) during low-power laser irradiation, which applied to the exposed sural nerve between the stimulus site and the recording site. The suppressive effect was reversible and recovered to the control level after the irradiation. Experimental evidence indicated that low-power laser irradiation suppressed the impulse conduction of unmyelinated A delta afferents in peripheral sensory nerve, which caused a pain sensation. Our data suggest that low-power laser acts as a reversible direct suppressor of neuronal activity.

Animals↗
PubMed1996

Effect of low-power laser irradiation on procollagen synthesis in human fibroblasts.

The conflicting views of the effect of low-power laser (LPL) irradiation on procollagen synthesis have existed at the present time, whereas many clinical studies have tested usefulness of LPL irradiation for the wound healing. To evaluate the effect of LPL irradiation on the procollagen synthesis of human fibroblasts in vitro, LPL irradiation on human fibroblast was carried out using two different culture medium, serum-starved medium and fetal calf serum (FCS)-contained medium. In addition, to investigate the mechanism of the LPL on the procollagen synthesis of human fibroblasts, dexamethasone and methylene blue contained medium were used for inhibition of procollagen product at the pretranslational level and cGMP-mediated processes, respectively. Enhanced effect of LPL was consistently observed in the serum-starved medium (50% increase by a 3 min irradiation), not in the FCS-contained medium. The LPL enhanced effect was not blocked by dexamethasone (3% inhibition) but methylene blue (40% inhibition). Our data suggest that some factors in FCS might interfere with the enhanced effect of LPL on procollagen synthesis and the LPL might act as a direct stimulator of the procollagen synthesis. It seems probable that the LPL enhanced effects might be occurred at the translational level or at the pretranslational level, which is not affected by dexamethasone and cGMP, might be involved in the LPL enhanced effect of the procollagen synthesis in fibroblast.

Cells, Cultured↗
PubMed1996

Presence in Pieris rapae of cytotoxic activity against human carcinoma cells.

Cytotoxic activity in extracts of pupae and adults of various kinds of butterflies and moths was tested in vitro against the human gastric carcinoma cell line, TMK-1, which was chosen as an example of human carcinoma cells. Among the species examined, cytotoxicity was limited to Pieris rapae, Pieris napi and Pieris brassicae. Activity was found down to a dilution of 1/10(4), while with the other butterflies and moths no activity was observed, even at 1/10(2). When the cytotoxicity of the three developmental stages, larvae, pupae and adults, of Pieris rapae was compared, the pupae showed the strongest activity, the IC50 against TMK-1 cells being at the 1/10(6) dilution. For larvae and adults, the respective IC50 values were at the 1/10(5) and 5/10(5) dilutions. The active principle in the pupae of Pieris rapae was found to be heat-labile and not extractable with organic solvents, but precipitated with ammonium sulfate and digested by proteases, suggesting that it is a protein. This cytotoxic factor was named pierisin.

Animals↗
PubMed1996

Effects of ACE inhibition and beta-blockade on skeletal muscle fiber types in dogs with moderate heart failure.

The proportion of slow-twitch, fatigue-resistant type 1 skeletal muscle (SM) fibers is often reduced in heart failure (HF), while the proportion of fatigue-sensitive type-II fibers increases. This maladaptation may be partially responsible for the exercise intolerance that characterize HF. In this study, we examined the effects of early monotherapy with the angiotensin-converting enzyme inhibor, enalapril, and the beta-blocker, metoprolol, on SM fiber type composition in 18 dogs with moderate HF produced by intracoronary microembolizations. HF dogs were randomized to 3 mo therapy with enalapril (10 mg twice daily), metoprolol (25 mg twice daily), or no treatment. Triceps muscle biopsies were obtained at baseline, before randomization, and at the end of 30 mo of therapy. Type I and type II SM fibers were differentiated by myofibrillar adenosinetriphosphatase (pH 9.4). In untreated dogs, the proportion of type I fibers was 27 +/- 1% before randomization and decreased to 23 +/- 1% (P < 0.05) at the end of 3 mo of follow up. In dogs treated with enalapril or metoprolol, the proportion of type I fibers was 30 +/- 4 and 28 +/- 2% before randomization and 33 +/- 4 and 33 +/- 1%, respectively, after 3 mo of therapy. In conclusion, in dogs with moderate HF, early therapy with enalapril or metoprolol prevents the progressive decline in the proportion of type I SM fibers.

Adrenergic beta-Antagonists↗
PubMed1996

Generalized pruritus in anorexia nervosa.

We report a 19-year-old woman with the associated disorders of generalized pruritus, hypertrichosis and anorexia nervosa, all of which had been present for approximately 4 months. Psychotherapy induced both weight gain and resolution of the pruritus. We propose that anorexia-associated pruritus be considered one of the important cutaneous signs in anorexia nervosa.

Adult↗
PubMed1996

[A case of spontaneous esophageal rupture successfully treated with a pedicled omental flap].

We experienced a case of spontaneous esophageal rupture. A 64-year-old male was admitted to the hospital with shock because of a severe epigastralgia after vomiting. We suspected spontaneous esophageal rupture by the mediastinal air and left pleural effusion of a chest X-ray film of first visit, and diagnosed it by esophagography, then operated 8 hours later the onset. On operation, following the primary closure the esophageal rupture, the pedicled omental flap was applied over the suture site. He complicated renal failure and multiple organ failure, but not leakage postoperatively. In a review of clinical cases seen in the literature, we recommend early operation and the adjunctive use of the pedicled omental flap.

Esophageal Diseases↗
PubMed1995

Retinoic acid enhances plasminogen activation on the cell surface.

The importance of cell-associated plasminogen activation in the extracellular matrix degradation processes is becoming increasingly evident. To elucidate the modulators of net plasminogen activation on the cell surface, we have recently established an assay system. Using this system, we examined the effects of several candidate modulators on cell surface plasminogen activator in the human fibrosarcoma cell line HT-1080 and the SV40-transformed human lung fibroblast cell line WI-38 VA 13 2RA. Although the majority of the candidates had no effect or a selective effect on either cell line, only retinoic acid markedly enhanced cell surface plasminogen activator activity in both HT-1080 and WI-38 VA13 2RA cells in a time-dependent manner. The effect of retinoic acid was neutralized by actinomycin D. The enhanced activity was inhibited by anti-uPA IgG and by pretreatment with phosphatidylinositol-specific phospholipase C. These findings suggest that retinoic acid increases the amount of receptor-bound uPA via de novo synthesis, and that it plays an important role in modulating cell-associated plasminogen activation.

Cell Line, Transformed↗
PubMed1995

Effects of long-term therapy with enalapril on severity of functional mitral regurgitation in dogs with moderate heart failure.

OBJECTIVES: This study examined the effects of early long-term monotherapy with enalapril on the severity of functional mitral regurgitation in dogs with moderate heart failure. BACKGROUND: Functional mitral regurgitation often develops in patients with heart failure and, depending on its severity, can have a marked adverse impact on the stroke output of the failing left ventricle and contribute to progressive deterioration of the heart failure state. METHODS: Left ventricular dysfunction (ejection fraction 30% to 40%) was produced in 14 dogs by multiple sequential intracoronary microembolizations. Dogs were randomized to 3 months of therapy with enalapril (10 mg twice daily, n = 7) or no therapy at all (control, n = 7). The severity of functional mitral regurgitation was quantified by Doppler color flow mapping in seven control and six enalapril-treated dogs. Mitral annular diameter was assessed by echocardiography and left ventricular volumes and shape by ventriculography. Measurements were made before initiation and after completion of therapy. RESULTS: In control dogs, the severity of mitral regurgitation increased during the follow-up period ([mean +/- SEM] 14 +/- 4 vs. 23 +/- 4%, p < 0.001) and was associated with increased left ventricular end-systolic and end-diastolic volumes. In contrast, the severity of regurgitation was not significantly changed in dogs treated with enalapril (18 +/- 3 vs. 16 +/- 6%, p < 0.59) and was associated with preservation of left ventricular volumes. CONCLUSIONS: In dogs with moderate heart failure, early long-term therapy with enalapril prevents progressive worsening of functional mitral regurgitation. This beneficial effect is most likely achieved by prevention of progressive left ventricular dilation.

Animals↗
PubMed1995

Epiretinal membrane formation. Light and electron microscopic study in an experimental rabbit model.

OBJECTIVE: To clarify the role of retinal glial cells in epiretinal membrane formation. METHODS: We injected autologous whole blood into the vitreous cavity of albino rabbits and studied the events in the vitreoretinal interface at intervals during the course of 1 year by light and electron microscopy. RESULTS: Epiretinal membranes were first found 2 weeks after the treatment. At this stage, epiretinal membranes were composed of both glial cells and macrophages. Mitotic figures of glial cells were found in the retina. The nuclei of glial cells migrated, passing through the inner limiting membrane and onto the retinal surface. At 6 months, macrophages and red blood cells disappeared from the epiretinal membranes. The epiretinal membranes became thicker with time. Finally, these epiretinal membranes were composed solely of glial cells. CONCLUSIONS: At the early stage, macrophages participate with glial cells in epiretinal membrane formation; however, glial cells are the main constituent of epiretinal membranes during the late stage.

Animals↗
PubMed1995

Ocular findings in Japanese women with nevus of Ota.

BACKGROUND: Nevus of Ota is common in Japanese women, but most patients are not examined ophthalmologically. METHODS: We performed ophthalmologic examinations on 16 Japanese women who had had bluish pigmentation in the periorbital region, sclera, and conjunctiva since birth. RESULTS: Fifteen patients had unilateral involvement, and one had bilateral lesions. The visual acuities were good, and the intraocular pressures were within normal range. All patients had a negative family history. Three patients had light pigmentation in the optic disc in the affected eye. CONCLUSION: We believe that optic disc pigmentation associated with nevus of Ota, as found in these three patients, may be common but have been rarely described.

Adolescent↗
PubMed1995

Developmental expression of KG-CAM in the rat neostriatum.

The present study examines the developmentally regulated expression pattern of an Ig superfamily member, KG-CAM, in the neostriatum of the rat. KG-CAM is a 90-kDa glycoprotein that is related to the DM-GRASP/Neurolin family of adhesion molecules. In the embryonic and early postnatal neostriatum, the distribution of KG-CAM correlates with the distribution of dopaminergic terminals. Early in neostriatal development, KG-CAM is found in the tyrosine hydroxylase-positive patches. In the maturing neostriatum, the levels of KG-CAM remain high within the patches, and KG-CAM upregulates in the matrix compartment. As the neostriatum is reaching its adult morphology, 5 weeks postnatal, the expression of KG-CAM in the matrix is approximately equal to that of the patches. When the distribution of KG-CAM is examined at the ultrastructural level, the immunoreactivity is localized to the external surface of neuronal and glial profiles in the neuropil. KG-CAM does not appear to be associated with the guidance of dopaminergic axons from the substantia nigra to the striatum, for this pathway is not immunopositive for this member of the Ig superfamily. The present study identifies an Ig superfamily member, KG-CAM, that appears to play a major role in the development of the neostriatum. Furthermore, the high levels of KG-CAM in the adult neostriatum suggest that this Ig superfamily member may be involved in maintaining the integrity of this structure in the adult rat.

Activated-Leukocyte Cell Adhesion Molecule↗
PubMed1995

Effects of contact sensitizers neomycin sulfate, benzocaine and 2,4-dinitrobenzene 1-sulfonate, sodium salt on viability, membrane integrity and IL-1 alpha mRNA expression of cultured normal human keratinocytes.

The toxic effect of three potential contact sensitization chemicals [the aminoglycosidic antibiotic neomycin sulfate, the local anaesthetic benzocaine and the primary sensitizer 2,4-dinitrobenzene 1-sulfonate, sodium salt (DNBS)], on cultured human keratinocytes was examined. The three chemicals were compared with respect to their cytotoxic potential (determined by crystal violet staining assay), their membrane disruptive potential ([3H]arachidonic acid release assay), and their effects on interleukin 1 alpha (IL-1 alpha) mRNA expression [reverse transcription-polymerase chain reaction (RT-PCR)]. At the concentrations used, neomycin sulfate (0.004-0.32%) and benzocaine (0.0165-0.165%) did not show relevant cytotoxicity or membrane perturbation. On the other hand, DNBS (0.001-1%) caused a significant dose-dependent cytotoxic response at concentrations higher than 0.1%, while the [3H]arachidonic acid release assay indicated absence of membrane perturbation activity in all the range of DNBS concentrations examined. The effects of the three sensitizers on IL-1 alpha mRNA expression were varied; neomycin sulfate caused a dose-dependent induction of IL-1 alpha mRNA, benzocaine did not significantly affect its signal, and DNBS suppressed IL-1 alpha gene expression.

Arachidonic Acid↗
PubMed1995

Long-term follow up of visual acuity in eyes with stage 5 retinopathy of prematurity after closed vitrectomy.

PURPOSE: This study was done to determine the efficacy of closed vitrectomy on long-term visual acuity of stage 5 retinopathy of prematurity. METHODS: We studied the visual acuity of eyes that had undergone retinal reattachment by closed vitrectomy for stage 5 retinopathy of prematurity and were followed up for more than three years. RESULTS: Forty-nine eyes of 31 patients among a total of 71 eyes of 48 consecutive patients were operated on and followed up for more than three years. Retinal reattachment occurred in 29 (59%) of the 49 eyes. Six patients (eight eyes) did not respond to visual acuity testing because of mental retardation or cerebral palsy. Measured visual acuity in the remaining 21 eyes varied from no light perception in one eye, light perception in four eyes, Recognizable hand movement in three eyes, 20/2,000 to 20/200 in seven eyes, 20/200 to 20/25 in five eyes, and 20/25 in one eye. No correlation was seen between visual outcome and factors such as gestational age, birth weight, and configuration of retinal detachment. Markedly better visual acuity was obtained in eyes that underwent initial surgery within four months of birth. CONCLUSIONS: Useful vision can be obtained after reattachment of the retina by closed vitrectomy on some patients who have stage 5 retinopathy of prematurity. Better visual acuity may be obtained by earlier surgery.

Birth Weight↗
PubMed1995

Effects of cyclosporin and ultraviolet radiation on growth and ornithine decarboxylase activity in cultured human epidermal keratinocytes.

Both cyclosporin (CyA) and ultraviolet radiation are effective in the treatment of psoriasis, but their precise mechanisms of action are uncertain. We investigated their effects on ornithine decarboxylase (ODC) activity, ODC gene expression, and cellular proliferation stimulated by epidermal growth factor (EGF), in cultured normal human epidermal keratinocytes. CyA (5 micrograms/ml) inhibited ODC activity, ODC mRNA level, and cell growth induced by 50 ng/ml EGF. Ultraviolet B (10 mJ/cm2) irradiation suppressed the induction of ODC, ODC mRNA, and cell proliferation stimulated by EGF, but ultraviolet A (0-15 J/cm2) irradiation inhibited neither EGF-stimulated ODC activity nor cell proliferation. These findings indicate that reduction of ODC activity in CyA- or ultraviolet B-treated human keratinocytes may contribute to the antiproliferative mechanism of these agents. These results also suggest that the regulation of ODC activity by ultraviolet B and A irradiation may be mediated by different signal transduction pathways.

Cell Division↗
PubMed1995

Inhibition of cytokine gene expression in mouse skin by subcutaneous injection of cyclosporine.

Cyclosporine A (CsA) has been shown to be an effective therapeutic agent for a wide variety of cutaneous diseases yet its exact mechanism of action is still unclear, although one well-defined effect of CsA is the inhibition of T-cell-derived cytokine expression. We recently demonstrated in vitro that CsA inhibits cell proliferation and suppresses cytokine gene expression in keratinocytes. In this study, we report the in vivo effects of CsA on skin cytokine gene expression as determined by reverse-transcriptase polymerase chain reaction. C57BL6 mice (female, 8-10 weeks old) were subcutaneously injected with CsA in olive oil (0, 5 and 10 mg/kg) every other day for 3 weeks. Treatment with 5 mg/kg CsA inhibited both interleukin (IL)-1 alpha and tumor necrosis factor alpha gene expression by about 70 and 90%, respectively, relative to vehicle control levels. However, IL-6 gene expression did not significantly change. Injection of 10 mg/kg CsA inhibited expression of all three genes by 80-90% relative to control levels. These data show that CsA can inhibit constitutive cytokine gene expression in mouse skin.

Animals↗
PubMed1995

Repetitive sperm-induced Ca2+ transients in mouse oocytes are cell cycle dependent.

Mature mouse oocytes are arrested at metaphase of the second meiotic division. Completion of meiosis and a block to polyspermy is caused by a series of repetitive Ca2+ transients triggered by the sperm at fertilization. These Ca2+ transients have been widely reported to last for a number of hours but when, or why, they cease is not known. Here we show that Ca2+ transients cease during entry into interphase, at the time when pronuclei are forming. In fertilized oocytes arrested at metaphase using colcemid, Ca2+ transients continued for as long as measurements were made, up to 18 hours after fertilization. Therefore sperm is able to induce Ca2+ transients during metaphase but not during interphase. In addition metaphase II oocytes, but not pronuclear stage 1-cell embryos showed highly repetitive Ca2+ oscillations in response to microinjection of inositol trisphosphate. This was explored further by treating in vitro maturing oocytes at metaphase I for 4-5 hours with cycloheximide, which induced nuclear progression to interphase (nucleus formation) and subsequent re-entry to metaphase (nuclear envelope breakdown). Fertilization of cycloheximide-treated oocytes revealed that continuous Ca2+ oscillations in response to sperm were observed after nuclear envelope breakdown but not during interphase. However interphase oocytes were able to generate Ca2+ transients in response to thimerosal. This data suggests that the ability of the sperm to trigger repetitive Ca2+ transients in oocytes is modulated in a cell cycle-dependent manner.

Animals↗