[Therapeutic trial of NMDA antagonist for a nonketotic hyperglycinemic infant].
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Amino Acid Metabolism, Inborn Errors↗
Biomedical subjects
T Tokoro
Publications and source records attributed to T Tokoro.
Expression of bFGF and TGF-beta 2 in experimental myopia in chicks.
PURPOSE: To determine factors that control ocular enlargement in experimental form-deprivation myopia and to clarify the mechanism of form-deprivation myopia. METHODS: After the left eyes of 20 chicks were monocularly occluded for 2 weeks, protein, basic fibroblast growth factor (bFGF) and transforming growth factor (TGF)-beta 2 contents in samples of constant area (circular button, diameter = 8.5 mm) in the retina-retinal pigment epithelium (RPE)-choroid and the sclera in the posterior region of control and myopic eyes were determined by enzyme-linked immunosorbent assay. RESULTS: The bFGF content (per circular button) and bFGF concentration (per mg protein) were significantly lower in the sclera in the posterior region of the myopic eyes than in control eyes. The bFGF content and concentration were similar in the retina-RPE-choroid in myopic and control eyes. The TGF-beta 2 content and concentration were significantly higher in myopic eyes in both the retina-RPE-choroid and the sclera (P < 0.05). CONCLUSIONS: These results are consistent with the possibility that bFGF and TGF-beta 2 regulate ocular enlargement or respond to myopiagenic mechanisms in form-deprivation myopia.
Animals↗
[Measurement of temporal summation of visual acuity with the use of a trial tachistoscope].
Visual acuity was measured in eighteen normal eyes of 10 subjects ranging from 20 to 30 years of age, using a modified tachistoscope. We changed the exposure time of the target (1-1,000 msec) or background luminance (0.1-200 cd/m2). The visual acuity rose with increasing exposure time. At background luminance over 10 cd/m2, the critical duration time was about 500 msec. However, at low luminance below 10 cd/m2, the critical duration was prolonged. This tendency was also seen when the pupil diameter was fixed at 3 mm with an artificial pupil. Similar by luminance detection, visual acuity was also determined by the product of background luminance and exposure time. From theses findings, we concluded that Bloch-Bunsen-Roscoe law was statisfied.
Adult↗
The attenuated elevation of cytoplasmic calcium concentration following the uptake of low density lipoprotein in type C Niemann-Pick fibroblasts.
In Niemann-Pick disease type C fibroblasts, the deficiency of cholesterol esterification has been reported. In this experiment, we detected the attenuated elevation of cytoplasmic calcium concentration following low density lipoprotein uptake in the fibroblasts. Moreover, we administered calcium channel agonist (0.5 microM YC-170) and calcium channel antagonists to the fibroblasts. YC-170 improved the attenuated elevation of calcium concentration and the deficient cholesterol esterification by 40% and 90% respectively. Calcium channel antagonists decreased the cholesterol esterification in normal and affected fibroblasts. These data indicated that the attenuated elevation of cytoplasmic calcium concentration was strongly related to the etiology of this disease.
Calcium↗
Scleral cell growth is influenced by retinal pigment epithelium in vitro.
BACKGROUND: Studies of form-deprivation myopia in chicks have shown that mitotic activity and the amounts of DNA and protein are increased in the sclera of myopic eyes. Signals acting on the sclera have been speculated to have their origin in the retina, especially in the photoreceptors and the retinal pigment epithelium (RPE). Therefore, in this study we investigated the interaction between the RPE cells and the scleral cells in vitro using chick embryo. METHODS: At first, we established the method for primary culture of scleral chondrocytes and scleral fibroblasts from chick embryos. Then, we co-cultured scleral chondrocytes with RPE cells and also co-cultured scleral fibroblasts with RPE cells. Scleral cells were cultured on a collagen membrane or Transwell-COL, with RPE cells cultured at the bottom of the dishes. We evaluated the effects of co-cultured RPE cells on the proliferation of scleral cells by counting the cell number of scleral cells on those membranes. RESULTS: With the co-cultured RPE cells, proliferation of the scleral chondrocytes was inhibited on a collagen membrane, but significantly stimulated on a Transwell-COL. Proliferation of the scleral fibroblasts was also promoted on the Transwell-COL with RPE cells. CONCLUSION: RPE cells influenced the proliferation of scleral cells in vitro, which suggests that RPE may, at least in part, act on the sclera in vivo to regulate ocular growth postnatally.
Animals↗
Type C Niemann-Pick disease fibroblasts and their transformed cell lines are hypersensitive to HMG-CoA reductase inhibitors.
The deficiency of exogenous cholesterol transport within fibroblasts of Niemann-Pick disease type C (NPC) has been addressed. In this report we confirmed that the endogenous synthesis of cholesterol within cells was markedly increased in NPC fibroblasts and those transformed by origin-defective simian virus 40. The transformed fibroblasts and those of the primary culture were hypersensitive to 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors as a consequence of their dependence on endogenous cholesterol biosynthesis. The transformed fibroblasts should help further biochemical and genetic research in this condition.
Cell Line, Transformed↗
Ocular pulse and pulsatile change of scleral strain in living in situ rabbit eyes.
We investigated ocular pulse (OP), pulsatile change of scleral strain (PSS), and intraocular pressure (IOP) to evaluate extensibility of the sclera in seven living rabbit eyes. OP and IOP were measured by a semiconductor pressure transducer and PSS was measured using a small foil strain gauge. Both OP and PSS generated similar bell-shaped curves in relation to IOP. Between OP and PSS, there was a linear relation, the gradient of which was considered to be an index of the modulus of elasticity of the sclera. With further refinement of the method, it is possible to apply this technique to human eyes.
Animals↗
Accommodation in astigmatic eyes.
PURPOSE: To investigate the effect of target chart contours and the severity of astigmatism on accommodation in astigmatic eyes. METHODS: The accommodative responses of 30 subjects were measured with an automated refractometer (Canon RK-1) using star pattern and bar pattern targets. RESULTS: The mean accommodative response was greatest when the bar pattern was parallel to the stronger principal meridian of the eye, followed by the star pattern and the bar pattern parallel to the weaker meridian on both meridians. Similar results were obtained in subjects with astigmatism greater or less than 1.25 D. The mean slopes of AR/AS plots decreased in the same order as the accommodative response and the change was significant in subjects with astigmatism exceeding 1.25 D. In addition, about one-third of the subjects showed a consistent decrease in astigmatism with accommodation. CONCLUSIONS: These results indicate that the type of target chart and the severity of astigmatism influence the accommodative response.
Accommodation, Ocular↗
Asthenopia and the dark focus of accommodation.
To study asthenopia, we compared the dark focus of accommodation of 54 symptomatic and 56 asymptomatic control subjects. The two groups were matched for age and cycloplegic refractive error. Symptomatic subjects were defined as those who complained of asthenopia daily even though their refractive error had been corrected. Subjects with other eye diseases that could produce asthenopia such as strabismus or aniseikonia were excluded. Using a Nidek Autorefractometer AR1600, we first measured non-cycloplegic refractive error (Non-Cyclo R) in a bright room, then the dark refractive state (Dark R) in complete darkness using the instrument with the optical target light extinguished and, finally, determined the cycloplegic refractive error (Cyclo R) after instilling cyclopentolate hydrochloride. The difference between Dark R and Cyclo R was defined as DFcus (Cyclo R) and that between Dark R and Non-Cyclo R as DFcus (Non-Cyclo R). We found both DFcus (Cyclo R) and DFcus (Non-Cyclo R) to be smaller in the symptomatic than in the asymptomatic subjects, indicating that asthenopia is associated with a low rather than a high level of tonic accommodation.
Accommodation, Ocular↗
Dark focus of accommodation and vergence posture.
We evaluated the dark focus of accommodation and vergence posture in 20 boys and girls, 10 with and 10 without accommodative esotropia, before and after they wore glasses for at least 1 month. Refractive error was measured by Nidek Autorefractometer AR1600. We used two definitions of the dark focus, DFcus (Non-Cyclo R) and DFcus (Cyclo R). DFcus (Non-Cyclo R) = Dark R - Non-Cyclo R. DFcus (Cyclo R) = Dark R - Cyclo R. (Dark R: refractive state in the dark; Non-Cyclo R: non-cycloplegic refractive error; Cyclo R: cycloplegic refractive error.) Vergence posture was measured by prism cover test during distance fixation while uncorrected. DFcus (Cyclo R) was significantly greater in esotropic subjects than in non-esotropic subjects, although DFcus (Non-Cyclo R) did not differ significantly. A significant hyperopic shift in Dark R was observed after wearing glasses. DFcus (Cyclo R) was significantly decreased after wearing glasses, suggesting that wearing glasses is an important variable of the dark focus. Unlike the dark focus, the vergence posture did not change in either group after wearing glasses. The dissociation of the dark focus from vergence posture seems to be inconsistent with previous findings. It is postulated that change in dark vergence after wearing glasses is responsible for the results.
Accommodation, Ocular↗
[Effects of Chinese medicine on bovine ciliary muscles].
We studied the effects and characteristics of Chinese medicines (Gorei-san (I), Saiko-keishi-to (II), Ryokei-jutsu-kan-to (III), Shokenchu-to (IV)), on the contractions (A) of bovine ciliary muscles. Ciliary muscle strips (width 4 mm x length 6 mm) were prepared and were contracted by a cholinergic agent, carbachol (10(-5)M). The 4 Chinese medicines were diluted to the concentrations of 10(-3)-10(-6) of each adult dosage per day. When these diluted medicines were added, all caused relaxations in a concentration-dependent manner. The percentages of (max B/max A) x 100 were: Gorei-san, 41 +/- 14 (%) (n = 6, mean +/- SD); Saiko-keishi-to, 37 +/- 18% (n = 6); Ryokei-jutsukan-to, 26 +/- 16% (n = 6); and Shokenchu-to, 10 +/- 5% (n = 6). Compared to the control group which did not receive Chinese medicines, drugs I, II and III showed statistically significant relaxation effects (p < 0.05). The amount of relaxation caused by these medicines (I-III) was 1/3-1/4 of the relaxation caused by a cholinergic antagonist, cyclopentlate (10(-5)M). The results suggest that Chinese medicines (I-III) produce moderate relaxation of ciliary muscles.
Animals↗
[Mechanism of axial elongation and chorioretinal atrophy in high myopia].
Myopic chorioretinal atrophy with axial elongation is one of the main factors of visual impairment in high myopia. To clarify the causes of this chorioretinal atrophy (CRA), the mechanism of ocular axial elongation was investigated from the effects of growth factors on experimental myopia models. From the analysis of large numbers of humans with extreme myopia, the factors causing CRA and the process of progression of this atrophy were also studied. I. Mechanism of ocular axial elongation Myopic change of 20 to 30 diopters occurred in chicks when they wore translucent or black opaque goggles for 2 weeks. But when they were fed under dark conditions for 24 hours, myopic change did not occur, and even when the goggles were worn, only slight myopic changes occurred. Thus, it appeared that light was necessary for myopic change and an increase in temperature caused by the goggles had little influence on the myopic change. In light microscopic observations, the posterior sclera of myopic chick eyes had thicker cartilaginous sclera and thinner fibrous sclera than the normal controls and abnormal proliferation of chondrocytes was seen at the border area. To investigate the changes in cell proliferation at 3 different locations (periphery, equator, posterior pole) of the sclera, the ratio of positive cells in PCNA, Decorin, b-FGF, TGF-alpha, TGF-beta, IGF-II, and phosphotyrosine were studied immunohistologically. Positive ratios were higher at the posterior pole of the treated myopic eyes for all factors, except for b-FGF and TGF-alpha. We estimated that the proliferation of chondrocytes and revelation of growth factors were higher at the posterior pole of the sclera in the experimental myopic eye than in the control eyes. In electron microscopic observations, proliferation of chondrocytes in cartilaginous sclera was found and small diameter collagen fibrils with a large amount of ground substance were observed in the fibrous sclera. These observations were similar to those of the sclera before hatching. It appeared that the sclera of the experimental myopic eyes remained in the pre-hatching condition. In co-culture experiments of the cultured condrocytes of cartilaginous sclera and the retina (retinal pigment epithelium (RPE) excluded), proliferation of the chondrocytes was suppressed significantly (p < 0.05). On the other hand, in the co-culture of chondrocytes and RPE-choroid, increase of the chondrocytes was induced (p < 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)
Adult↗
[Characteristics of contraction force of bovine ciliary muscles caused by cholinergic agent].
We studied the contractions caused by the cholinergic agent carbachol on bovine ciliary muscles. Ciliary muscle strips (width 4 mm x length 6 mm) were prepared in the directions of the longitudinal and circular muscles. Contractions were measured with an isometric tension recorder. The concentration for 50% effective dose was 10(-7) M carbachol, and maximum contraction was obtained at 3 x 10(-6) M. Also, maximum contraction was obtained at a resting tension of 600 mg for the longitudinal direction and 400 mg for the circular direction. At a resting tension of 400 mg and concentration of 10(-5) M, average contraction for the longitudinal direction (L) was 335 +/- 106 mg (mean +/- SD, n = 20) and 104 +/- 52 mg (mean +/- SD, n = 20) for the circular direction (C). The ratio between L and C was about 3:1. The results suggest that bovine ciliary muscles have more ability to perform accommodation than in previous reports, and that the magnitude of contractions depends on the direction of the ciliary muscle fibers.
Animals↗
[Mechanical characteristics of the bovine choroid].
We studied the mechanical relationship between the tension and the length of stretch of bovine choroids. Longitudinal and circular choroidal strips (4 mm x 6 mm) were prepared at 3 different locations (I. ora serrata, II. anterior to the equator, III. posterior to the equator). Using a force transducer and a potentiometer, changes in the tension and the length of stretch were recorded simultaneously. At a tension of 600 mg, longitudinal strips stretched more than circular strips at all 3 locations (p < 0.05). Longitudinal strips all stretched to almost the same length (about 1.3 mm), but circular strips stretched less in the order of I, II and III. These results suggest that there are mechanical characteristics in the bovine choroid allowing it to stretch more in the longitudinal direction than in the circular direction.
Animals↗
Successfully treated optic nerve infiltration with adult T-cell lymphoma.
A 45-year-old woman with adult T-cell leukemia had a sudden onset of decreased vision with central scotoma in the right eye. Right optic disc edema and thickening of the optic nerve were observed by magnetic resonance imaging. A diagnosis of leukemic infiltration to the optic nerve was made. A course of oral corticosteroid therapy was prescribed and 40 Gy of radiation was administered to the whole brain and right orbit. Her visual acuity recovered from finger counting to 20/20 within 3 weeks. We believe that this patient represents the first report of successfully treated optic nerve infiltration with adult T-cell leukemia caused by human T-lymphotropic virus type-I infection.
Female↗
[A possible same genetic defect in two Niemann-Pick disease model mice].
We found two Niemann-Pick disease model mouse species, NCTR-BALB/c mouse and SPM mouse. NCTR-BALB/c mouse is known as a model mouse of Niemann-Pick disease type C, because cholesterol esterification is deficient in fibroblasts. On the other hand, SPM mouse has been thought as a model of Niemann-Pick disease type A. However, we disclosed cholesterol esterification in fibroblasts from SPM mice is also deficient. It indicates that two model mice could be caused by a same genetic deficiency. To test if the genetic defect of those mice are located in the same gene, we made NCTR-BALB/c mouse heterozygotes mate with SPM mouse heterozygotes. The F1 mice are investigated by lipid analysis, lysosomal enzyme assay, cholesterol esterification ratio, and electron microscopic study. Eleven in 42 F1 mice (25%) got affected, and the clinically affected F1 mice had the biological and morphological abnormalities which are seen in SPM and NCTR-BALB/c mice. These data suggest that genetic defects in NCTR-BALB/c and SPM mice are located in the same gene.
Animals↗
Time-varying properties of respiratory fluctuations in pupil diameter of human eyes.
The time varying properties have been investigated of respiratory components in fluctuations of the pupil diameter (PDF) of the human eye. PDF and instantaneous lung volume were simultaneously measured for 45 minutes under natural binocular viewing conditions. The short-term Fourier transform and the autoregressive signal modeling together with the recursive least squares algorithm have been applied for the estimation of nonstationary power spectra. Data analysis showed a bursting type non-stationarity in the appearance of the respiratory component in PDF.
Adult↗