Biomedical subjects

Yoshiko Takai

Publications and source records attributed to Yoshiko Takai.

4 recordsLinked to original sources

PubMed2005

Bagolini striated glasses test and lesions of the optic chiasm.

PURPOSE: To examine the usefulness of the Bagolini Striated Glasses Test to identify patients with a lesion of the optic chiasm. SUBJECTS AND METHODS: Twelve patients who were diagnosed with a lesion of the optic chiasm by MRI were examined with the Bagolini Striated Glasses Test. Discrepancies of the test between monocular and binocular conditions were analyzed. Visual acuity, visual field and stereo tests were also administered and assessed. RESULTS: Nine out of 12 cases (75%) showed conflicting results with the Bagolini Striated Glasses Test between monocular and binocular conditions. With monocular testing, essentially normal stripes were observed in each eye. In binocular testing, stripes which were projected upon nasal retina were suppressed bilaterally (bitemporal hemianopia pattern) ("mountain pattern") or monocularly (monocular temporal hemianopia pattern). CONCLUSION: The Bagolini Striated Glasses Test can be used as a simple differential diagnostic test for lesions of the optic chiasm. The "mountain pattern" seen binocularly on this test may be pathognomonic for such lesions, which may otherwise be asymptomatic and/or overlooked.

Adenoma↗

PubMed2005

Similar etiologies of functional visual loss observed in children and adults.

BACKGROUND AND PURPOSE: To describe four cases of functional visual loss which challenge the theory that its causes are different in children and adults (i.e., that financial gain is the primary cause in adults while in children it is an involuntary response to psychosocial problems). Rather, we will show a similar etiology of functional visual loss in children and adults. We also describe diagnostic testing and therapeutic approaches that are useful in both children and adults with functional visual loss. SUBJECTS AND METHODS: Two children (5 and 15 years old) and two adults (54 and 73 years old) with presumed functional visual loss and whose visual functions were assessed with verbal assurance, Starlight Test, Flicker Test, and trial glasses or contact lenses. RESULTS: Normal visual function was elicited in all four cases. In both pediatric patients we were able to elicit normal vision using verbal assurance and trial glasses or contact lenses. In both adult patients, we elicited dramatic improvements in vision with verbal assurance and discussion of the patients' psychosocial situation. CONCLUSION: Children and adults present with similar etiologies (psychosocial problems) of functional visual loss. In these cases we believe the children were motivated by their desire to wear glasses or contacts and the adults were involuntarily responding to psychosocial problems. These cases show that we cannot, as has been proposed, clearly categorize patients with functional visual loss based upon age.

Adolescent↗

PubMed2004

Two types of non-selective cation channel opened by muscarinic stimulation with carbachol in bovine ciliary muscle cells.

In the ciliary muscle, the tonic contraction requires a sustained influx of Ca2+ through the cell membrane. However, little has hitherto been known about the route(s) of Ca2+ influx in this tissue that lacks voltage-gated Ca2+ channels. To identify ion channels as the Ca2+ entry pathway we studied the effects of carbachol (CCh) on freshly isolated bovine ciliary muscle cells by whole-cell voltage clamp. Experiments were carried out using pipettes filled with K+ -free solution containing 100 mm caesium aspartate, 5 mm BAPTA and 180 microm GTP (pH 7.0; the intracellular free Ca2+ concentration, [Ca2+]i = 70 nm). CCh evoked an inward current showing polarity reversal at a holding potential near 0 mV. Analysis of the current noise distinguished two types of non-selective cation channel (NSCCL and NSCCS) with widely different unitary conductances (35 pS and 100 fS). The ratios of the permeabilities to Li+, Na+, Cs+, Mg2+, Ca2+, Sr2+ and Ba2+, estimated by cation replacement procedures, were 0.9: 1.0: 1.5: 0.2: 0.3: 0.4: 0.5 for NSCCL, and 1.0: 1.0: 1.8: 2.5: 2.6: 3.2: 5.0 for NSCCS. NSCCS, but not NSCCL, was strongly inhibited by elevation of [Ca2+]i. Both NSCCL and NSCCS were dose-dependently inhibited by 1-100 microm SKF96365, La3+ and Gd3+, which also inhibited the tonic component of the contraction produced in muscle bundles by CCh without markedly affecting the initial phasic component. NSCCL and/or NSCCS may serve as a major Ca2+ entry pathway required for sustained contraction of the bovine ciliary muscle. RT-PCR experiments in the bovine ciliary muscle (whole tissue) detected mRNAs of several transient receptor potential (TRP) channel homologues (TRPC1, TRPC3, TRPC4 and TRPC6), which are now regarded as possible molecular candidates for receptor-operated cation channels.

Animals↗

PubMedDate not supplied

Development of stereoscopic acuity: longitudinal study using a computer-based random-dot stereo test.

PURPOSE: To investigate the development of stereoscopic acuity (stereoacuity) in children longitudinally. METHODS: Seven full-term normal infants whose age at the beginning of the study was between 12 and 23 weeks were studied. A computer-based random-dot test of stereoscopic vision (TV-Random Dot Stereo Test) was used to measure stereoacuity. The test was repeated at 2- to 3-month intervals until the children reached 2 years of age, and then every 6 to 12 months until they reached 5 years of age. RESULTS: All of the infants were found to have a stereoacuity of 2480 seconds of arc (2480'') with this test by 26 weeks of age. The first reliable measurement of stereoacuity was obtained from a 16-week-old infant. Stereoacuity did not improve significantly between 6 and 12 months, but it improved rapidly after 12 months. All children had a stereoacuity of 100'' with the Titmus Stereo Tests at 5 years of age, but the best stereoacuity with the TV-Random Dot Stereo Test was 229'' at 28.9 months. CONCLUSIONS: The development of stereoacuity studied longitudinally was similar to that obtained by cross-sectional studies. The TV-Random Dot Stereo Test is a useful program for measuring stereopsis in preverbal children.

Child Development↗