Biomedical subjects

Kazuhiro Ishida

Publications and source records attributed to Kazuhiro Ishida.

7 recordsLinked to original sources

PubMed2006

Fellow eye of patients with retinal detachment associated with macular hole and bilateral high myopia.

PURPOSE: To estimate the risk of retinal detachment in the fellow eye of patients with bilateral high myopia who had retinal detachment associated with macular hole (MH-RD) in one eye. METHODS: The present study examined retrospectively 56 patients with bilateral high myopia who had MH-RD. To determine the incidence of involvement of the fellow eye, patients who completed a follow up of 12 months or longer were eligible for the current study. RESULTS: Of 56 patients with MH-RD due to high myopia, 54 had unilateral detachment at presentation and two had bilateral detachment. Of the 54 highly myopic fellow eyes without retinal detachment at presentation, 37 eyes underwent 12 or more months of documented follow up. Mean follow up after initial surgery to the primary eye was 6.5 +/- 4.9 years. During follow up, a macular hole without retinal detachment was noted in one (2.7%) of these 37 eyes. Three other eyes (8.1%) had MH-RD at 1, 2 and 7 years, respectively, after the initial surgery to the primary eye. At the final visit, 12 eyes (32%) had visual acuity of > or =6/9, whereas 12 eyes (32%) had visual acuity of < or =6/60. CONCLUSIONS: When patients with bilateral high myopia have MH-RD in one eye, they would be expected to be at increased risk of retinal detachment in the fellow eye.

Aged↗

PubMed2005

Immobilization of octadecyl ammonium chloride on the surface of titanium and its effect on microbial colonization in vitro.

The aim of our study was twofold: to immobilize an organosilicon quaternary ammonium salt (3-(trimethoxysilyl)-propyldimethyl-octadecyl ammonium chloride, Si-QAC) on the surface of pure titanium and to investigate the antimicrobial activity of Si-QAC-immobilized titanium against microbial adherence and biofilm formation. The results of ToF-SIMS analysis of Si-QAC-titanium suggested the possibility of immobilizing Si-QAC on titanium surface through Ti-O-Si coupling, and that Si-QAC treatment significantly reduced both the adherence and colonization of Candida albicans and Streptococcus mutans isolates. The antimicrobial activity was achieved through at least two mechanisms: the first was attributed to the octadecyl alkyl chain which inhibited initial adherence, and the second was attributed to the quaternary ammonium salt which killed initial adherent cells as well as retarded or inhibited subsequent microbial growth. Further, thermocycling did not significantly reduce the antimicrobial activity of Si-QAC-titanium, and no significant cytotoxicity of Si-QAC-titanium was observed in either cell viability test or proinflammatory cytokine production test using human gingival fibroblasts. These results, taken together, favorably suggested that Si-QAC treatment would be a helpful means to inhibit dental plaque or denture plaque formation.

Analysis of Variance↗

PubMed2004

Accurate and fast algorithm of the molecular incomplete gamma function with a complex argument.

Several efficient algorithms for the accurate and fast calculation of the molecular incomplete gamma function Fm(z) with a complex argument z are developed. The complex incomplete gamma function is arising in molecular integrals over the gauge-including atomic orbitals. Two kinds of algorithms are recommended: (1) a high-precision version and (2) a fast version. The high-precision version is able to guarantee 15 significant figures (10(-15) in the relative error) and the fast version is able to guarantee 12 significant figures (10(-12) in the relative error), at worst, within the double-precision arithmetic. The fast version is about 5-20 times faster than the high-precision version. For most molecular calculations, the fast version will give a satisfied precision.

Journal Article↗

PubMed2003

Molecular integrals over the gauge-including atomic orbitals. II. The Breit-Pauli interaction.

Each accompanying coordinate expansion (ACE) formula is derived for each of the orbit-orbit interaction, the spin-orbit coupling, the spin-spin coupling, and the contact interaction integrals over the gauge-including atomic orbitals (GIAOs) by the use of the solid harmonic gradient (SHG) operator. Each ACE formula is the general formula derived at the first time for each of the above molecular integrals over GIAOs. These molecular integrals are arising in the Breit-Pauli two-electron interaction for a relativistic calculation. We may conclude that we can derive a certain ACE formula for any kind of molecular integral over solid harmonic Gaussian-type orbitals by using the SHG operator. The present ACE formulas will be useful, for example, for a calculation of a molecule in a uniform magnetic field, for a relativistic calculation, and so on, with the GIAO as a basis function.

Journal Article↗

PubMed2003

Participation of pigment epithelium in ocular immune privilege. 3. Epithelia cultured from iris, ciliary body, and retina suppress T-cell activation by partially non-overlapping mechanisms.

PURPOSE: The ocular microenvironment is immunosuppressive and anti-inflammatory. Since various ocular pigmented epithelia contribute to this microenvironment, we studied the relative capacities of pigment epithelial (PE) cells cultured from the iris, ciliary body, and retina of mouse eyes to suppress T-cell activation in vitro. METHODS: Pigment epithelium was cultured from iris, ciliary body, and retina for 14 days, then assayed for the capacity, directly or across transwell membranes, to suppress mixed lymphocyte reactions and anti-CD3 stimulation of T cells. Potential molecules responsible for suppression were examined by attempting to block suppression with appropriate reagents, and by using mice with pertinent mutant or disrupted genes. RESULTS: We found that PE cells from all three ocular tissue sources profoundly suppressed T-cell activation in vitro. While iris PE suppressed poorly when separated from T cells by a transwell membrane (implying that cell contact is necessary), retina PE suppressed fully even in the presence of such a membrane (implying that soluble factors were responsible). Ciliary body PE used both soluble factors as well as cell contact to achieve suppression. Suppression could not be ascribed to TGFbeta, IFNgamma, TNFalpha, CD48, or ICAM-1, or to interactions between CD40 and CD154, or CD95 and CD95 ligand. Galectin-1, a galactoside-binding protein, was found to be expressed on all cultured PE cells, but only retinal pigment epithelium (RPE) from galectin-1 KO mice showed reduced capacity to inhibit T-cell activation. CONCLUSIONS: Cultured pigment epithelia from iris, ciliary body, and retina comparably suppress T-cell activation in vitro, but by partially different mechanisms. Although RPE cells suppress in part through expression of galectin-1, the molecular mediators of suppression by iris and ciliary body PE remain to be identified.

Animals↗

PubMed2002

Accompanying coordinate expansion formulas derived with the solid harmonic gradient.

A series of accompanying coordinate expansion (ACE) formulas for calculating the electron repulsion integral (ERI) over both generally and segmentally contracted solid harmonic (SH) Gaussian-type orbitals (GTOs) can be rederived by the use of the modified operator (called solid harmonic gradient here) of the spherical tensor gradient of Bayman and the reducing solid harmonic gradient defined in this article. The final general formulas contain the reducing mixed solid harmonics defined in a previous article [Ishida, K. J Chem Phys 1999, 111, 4913] and the reducing triply mixed solid harmonics defined previously [Ishida, K. J Chem Phys 2000, 113, 7818]. Each general formula in the series is named ACEb1k1, ACEb2k3, or ACEb3k3. New general algorithm can be obtained inductively from the general formula named ACEb2k3, in addition to the previously developed ACEb1k1 and ACEb3k3. For calculating ERI practically, we select one of these ACE algorithms, as it gives the minimum floating-point operation (FLOP) count. Theoretical assessment by the use of the FLOP count is performed for the (LL/LL) class of ERIs over both generally and segmentally contracted SH-GTOs (L = 1-3). It is found that the present ACE is theoretically the fastest among all rigorous methods in the literature.

Journal Article↗

PubMedDate not supplied

Visual field defect after radial optic neurotomy for central retinal vein occlusion.

PURPOSE: To evaluate visual field defects after radial optic neurotomy (RON) in eyes with central retinal vein occlusion (CRVO). METHODS: Eight patients (eight eyes) underwent RON for macular edema associated with CRVO. Goldmann perimetry was performed on each patient both before and after surgery. RESULTS: Postoperative Goldmann perimetry showed a temporally located wedge-shaped visual field defect consistent with neural damage secondary to RON in seven eyes (88%). After surgery, the visual field decreased from preoperative values by 7% at 3 months (P = 0.30) and by 21% at 12 months (P = 0.0023). Although three patients (38%) were aware of the postoperative visual field defect, only one patient (13%) considered this defect to be a visual disability. CONCLUSIONS: After RON, most patients showed a postoperative defect in the temporal visual field consistent with the incision to the optic disk. However, this visual field defect appears to be well tolerated by most patients.

Adult↗