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Biomedical subjects

Y Tano

Publications and source records attributed to Y Tano.

At least 91 records · Page 5Linked to original sources
PubMed1999

Methicillin-resistant Staphylococcus aureus infections after scleral buckling procedures for retinal detachments associated with atopic dermatitis.

OBJECTIVE: To determine the incidence and the clinical course of methicillin-resistant Staphylococcus aureus as a cause of acute-onset infections in patients with atopic dermatitis after a scleral buckling procedures. DESIGN: A retrospective chart review. PARTICIPANTS: Two hundred eighty-seven patients (293 eyes) who underwent scleral buckling procedures to treat rhegmatogenous retinal detachments at either Osaka Rosai Hospital or Osaka University Medical School between July 1, 1995, and June 30, 1997, participated. Of these, 32 eyes (10.9%) were associated with atopic dermatitis. INTERVENTION: Demographic and clinical data were abstracted from patients' medical records. MAIN OUTCOME MEASURES: The incidence, clinical features, and management of postoperative infections associated with methicillin-resistant S. aureus were studied. RESULTS: Methicillin-resistant S. aureus infection after scleral buckling procedures was identified in 6 (18.8%) of 32 eyes of patients with atopic dermatitis but in only 1 (0.4%) of the other 261 cases without atopic dermatitis (P < 0.001). The average interval from the scleral buckling procedures to the initial onset of infection was 8.3 +/- 9.1 days (range, 2-28 days). Bacterial infection and inflammation were controlled in four eyes by prompt removal of the infected buckle in combination with vancomycin administration. In the other three eyes, however, repeat intravitreous injections of vancomycin or emergent vitrectomies were required because of the development of endophthalmitis. CONCLUSIONS: Methicillin-resistant S. aureus is an important causative pathogen of scleral buckling infections, particularly in patients with retinal detachment associated with atopic dermatitis. Preoperative evaluation and intraoperative attention to contamination are recommended to prevent methicillin-resistant S. aureus infections in these patients.

Acute Disease↗
PubMed1999

Vitrectomy for rhegmatogenous or tractional retinal detachment with familial exudative vitreoretinopathy.

OBJECTIVE: To examine the anatomic features and surgical indications of familial exudative vitreoretinopathy (FEVR) complicated with rhegmatogenous or tractional retinal detachment. DESIGN: Retrospective noncomparative case series. PARTICIPANTS: Twenty-eight eyes of 25 patients who had either clinically suspected or fully diagnosed FEVR. Of these, 25 had rhegmatogenous retinal detachment, 2 had tractional retinal detachment, and 1 had tractional retinal detachment plus vitreous hemorrhage. INTERVENTIONS: The authors carefully observed the vitreoretinal interface during surgery, studied the clinical and anatomic features of FEVR, and then evaluated the surgical results. RESULTS: The vitreoretinal adhesions were so strong in the peripheral avascular area that iatrogenic retinal breaks easily occurred in 22 of 28 eyes. In all cases, the bimanual technique with vitreous scissors and forceps was required to dissect the posterior vitreous membrane from the retinal surface. The retina was reattached in 24 of 28 cases (85.7%), and visual acuity improved in 20 eyes (71.4%). CONCLUSION: Dissection of the vitreous in the peripheral avascular area is very difficult in FEVR, and those patients for whom this procedure was not successfully performed may have a poorer prognosis.

Adolescent↗
PubMed1999

Nonvitrectomizing vitreous surgery: a strategy to prevent postoperative nuclear sclerosis.

OBJECTIVE: The development or progression of postoperative nuclear sclerosis is the most common complication of successful vitrectomy in elderly patients. The authors treated idiopathic epimacular proliferation (EMP) with nonvitrectomizing vitreous surgery in an attempt to prevent postoperative nuclear sclerosis. DESIGN: Prospective, nonrandomized, comparative case series. PARTICIPANTS: The authors surgically removed membranes from the sensory retina in 21 eyes of 21 patients with EMP. INTERVENTION: Neither intravitreal infusion nor vitrectomy of any kind was performed during the procedure. The peeled membrane was left floating in the vitreous cavity in 11 (group 1) eyes and removed in 10 eyes (group 2). Nonoperated fellow eyes served as controls. MAIN OUTCOME MEASURES: Visual acuity, slit-lamp and/or Scheimpflug photography, and refractometry were performed pre- and postoperatively to evaluate changes in the degree of lenticular opacity. RESULTS: There was no difference in the rate of development or progression of nuclear sclerosis or the degree of myopic shift between operated and control eyes during the postoperative follow-up period (mean, 9.7 months). No serious complications were noted. There was no difference in postoperative course between patients in the two operative groups. CONCLUSIONS: Although interpretation of the results of this study is limited due to its small size and short follow-up, nonvitrectomizing vitreous surgery seems to decrease the postoperative development or progression of nuclear sclerosis in patients with idiopathic EMP.

Aged↗
PubMed1999

Identification of the gene responsible for gelatinous drop-like corneal dystrophy.

Gelatinous drop-like corneal dystrophy (GDLD; OMIM 204870) is an autosomal recessive disorder characterized by severe corneal amyloidosis leading to blindness, with an incidence of 1 in 300,000 in Japan. Our previous genetic linkage study localized the gene responsible to a 2.6-cM interval on chromosome 1p. Clinical manifestations, which appear in the first decade of life, include blurred vision, photophobia and foreign-body sensation. By the third decade, raised, yellowish-grey, gelatinous masses severely impair visual acuity, and lamellar keratoplasty is required for most patients. Here we report DNA sequencing, cDNA cloning and mutational analyses of four deleterious mutations (Q118X, 632delA, Q207X and S170X) in M1S1 (formerly TROP2 and GA733-1), encoding a gastrointestinal tumour-associated antigen. The Q118X mutation was the most common alteration in the GDLD patients examined, accounting for 33 of 40 (82.5%) disease alleles in our panel of families. Protein expression analysis revealed aggregation of the mutated, truncated protein in the perinuclear region, whereas the normal protein was distributed diffusely in the cytoplasm with a homogenous or fine granular pattern. Our successful identification of the gene that is defective in GDLD should facilitate genetic diagnosis and potentially treatment of the disease, and enhance general understanding of the mechanisms of amyloidosis.

Amyloidosis↗
PubMed1999

The effects of kallidinogenase on choroidal blood flow in a hypertensive rabbit model.

PURPOSE: The purpose of the present study was to investigate the effects of kallidinogenase on chorioretinal circulatory disorder, on the basis of chorioretinal blood flow and fundus findings, in a renal hypertensive rabbit model. METHODS: In a renal hypertensive rabbit model produced according to Goldblatt's method, chorioretinal blood flow was continuously measured by noncontact laser Doppler flowmetry (LDF). Ophthalmography was conducted before and 30 minutes after drug administration. RESULTS: Measurement by LDF revealed 16% reduction in chorioretinal blood flow in the hypertension group compared with the control group. The administration of kallidinogenase dose-dependently increased chorioretinal blood flow in both groups, the hypertension group being more sensitive to kallidinogenase than the control group. In contrast, none of the controls (vinpocetine and DL-alpha-tocopherol nicotinate) exerted effects on chorioretinal blood flow in the hypertension group. Fundus examination demonstrated narrowing of the choroidal arterioles following an increase in blood pressure, and expansion of the arterioles following the administration of kallidinogenase. CONCLUSION: Kallidinogenase was shown to improve ophthalmic circulation by increasing chorioretinal blood flow in renal hypertensive rabbits.

Animals↗
PubMed1999

Change in retinal sensitivity due to excision of choroidal neovascularization and its influence on visual acuity outcome.

PURPOSE: Excision of choroidal neovascular membranes (CNV) has been attempted as an alternative to photocoagulation for the management of subfoveal CNV. To evaluate functional results of CNV excision, we studied retinal sensitivity in the area corresponding to the CNV (CNV area). METHODS: Static microperimetry using a scanning laser ophthalmoscope was performed on 17 eyes before and after CNV excision. We studied whether CNV excision changed retinal sensitivity in the CNV area. To evaluate the relationship between retinal sensitivity and visual acuity, further testing was performed on nine patients who had subfoveal CNV from age-related macular degeneration (ARMD). RESULTS: Preoperatively, 5 of 17 eyes (29.4%) had retinal sensitivity in the CNV area. Postoperatively, 4 of 17 (23.5%) eyes had retinal sensitivity. Surgery did not significantly change retinal sensitivity in the CNV area (P>0.999). There was a significant correlation between the presence of retinal sensitivity and visual acuity. Postoperative visual acuity of eyes with retinal sensitivity in the CNV area was better than that of the eyes without sensitivity in the patients with subfoveal CNV from ARMD (P = 0.0017). CONCLUSIONS: In most cases, excision of CNV does not improve central retinal sensitivity, and patients have poor visual outcome. In some cases, however, postoperative sensitivity in the bed of CNV is preserved and visual outcome is relatively good. Better or worse preoperative retinal sensitivity does not predict better or worse visual acuity outcome, respectively.

Adult↗
PubMed1999

Concentration dependent effects of hydrogen peroxide on lens epithelial cells.

AIMS: To evaluate the effects of hydrogen peroxide exposure on the survival and proliferation of cultured lens epithelial cells. METHODS: TOTL-86 cells, a line of rabbit lens epithelial cells, were used. The survival and proliferation of TOTL-86 cells were quantified by a rapid colorimetric assay (MTT assay). To determine the effects of hydrogen peroxide, TOTL-86 cells were exposed to different concentrations of hydrogen peroxide. To determine the effect of cell numbers on the survival and proliferation of TOTL-86 cells at a fixed concentration of hydrogen peroxide, different numbers of cells were plated and exposed to hydrogen peroxide. To determine whether there is a synergistic effect between hydrogen peroxide and EGF, bFGF, PDGF-AA, and insulin, TOTL-86 cells were exposed to hydrogen peroxide combined with one of these growth factors. RESULTS: High levels (1 mM) of hydrogen peroxide killed TOTL-86 cells and sublethal levels (100 microM) suppressed their proliferation. From 1 nM to 1 microM of hydrogen peroxide, there was a dose dependent increase in the cell numbers. The initial seeded cell number dramatically affected the response to hydrogen peroxide. Although growth factors showed no synergistic effects with hydrogen peroxide on proliferation, both EGF and insulin, but not bFGF or PDGF, rescued TOTL-86 cells from the sublethal effect. CONCLUSION: Hydrogen peroxide in cooperation with some growth factors plays an important role in the proliferation of lens epithelial cell.

Animals↗
PubMed1999

The effect of nitric oxide on the contractile tone of Müller cells.

The effect of nitric oxide (NO) on the contractile tone of Müller cells was investigated. Müller cells, isolated from the retina of chick embryos, were cultured on thin sheets of silicone. S-Nitro-N-acetyl-DL-penicillamine (SNAP), an NO donor, was applied in the presence or the absence of carboxyl phenyltetramethylimidazole oxide (C-PTIO), an NO scavenger. The contractile tone of Müller cells was assessed by the extent of wrinkles created on the silicone sheets. The change of contractile tone was evaluated quantitatively by digitizing the photograph before and after the application of SNAP. Relaxation of wrinkles was induced by SNAP. C-PTIO inhibited the SNAP-induced relaxation of wrinkles. These results suggest that NO affects the contractility of embryonic Müller cells and could thus modulate ocular development.

Animals↗
PubMed1999

[Multicenter retrospective study of retinal detachment associated with atopic dermatitis].

PURPOSE: Epidemiological and clinical study of retinal detachment associated with atopic dermatitis. METHODS: A multicenter retrospective study. RESULTS: We analyzed 417 eyes of 348 patients operated on during the 5 years from 1989 to 1993 and followed up for more than 6 months by vitreo-retina specialists in 33 hospitals throughout Japan. The number of eyes operated increased yearly from 42 in 1989 to 132 in 1993. These were 2.3% of the average number of the eyes operated on for rhegmatogenous retinal detachment during the same period, but when restricted to the Kanto area or further to Tokyo only, the percentage was as high as 3.8% and 4.7% respectively. Clinical characteristics of retinal detachment previously reported, such as traumatic slapping or rubbing of the lids by patients as the most possible pathogenetic factor, and high incidence of cataract and proliferative vitreoretinopathy, were confirmed. The primary surgical procedure was scleral buckling in 78% of the cases and vitreous surgery in 22%, and initial and final reattachment rates were 75.3% and 92.6%, respectively.

Adolescent↗
PubMed1999

T-cell-mediated immune responses in alloepithelial rejection after murine keratoepithelioplasty.

PURPOSE: To evaluate the role of delayed-type hypersensitivity (DTH) and cytotoxic T-lymphocyte (CTL) responses on alloepithelial rejection in a murine keratoepithelioplasty model. METHODS: C3H/He mouse corneal lenticules were grafted around the limbus in BALB/c mice, and alloepithelial rejection was assessed by microscopic evaluation. The relation between rejection scores and DTH or CTL responses to donor antigens was assessed by Spearman correlation analysis. Suppression of DTH responses by induction of anterior chamber-associated immune deviation (ACAID) was used to evaluate the contribution of DTH responses to allograft rejection. CTL responses were evaluated by in vitro and in vivo depletion of CD4+ or CD8+ cells. RESULTS: DTH responses, which developed 2 weeks postoperatively, correlated significantly with rejection scores (correlation coefficient r = 0.55). ACAID induction by anterior chamber inoculation of C3H/He splenocytes significantly suppressed allospecific DTH responses and alloepithelial rejection. While allospecific CTL responses also developed 2 weeks postoperatively and increased by 4 weeks, CTL responses did not exhibit positive correlation with rejection scores (r = -0.36, P = 0.076). The CTL responses were mediated exclusively by CD8+ cells. Although in vivo depletion of CD8+ cells abolished the induction of CTL responses, it did not prevent allograft rejection. Immunohistochemistry showed infiltration of CD4+ and CD8+ cells into the alloepithelium. Positive staining for interferon gamma but not interleukin 4 further implicated the participation of a DTH response. CONCLUSIONS: Allograft rejection after keratoepithelioplasty appears to be mediated primarily by DTH responses, with CTL responses playing only a minor role perhaps in modifying the development of rejection.

Animals↗
PubMed1998

Specific detections of the early process of the glycation reaction by fructose and glucose in diabetic rat lens.

The glycation reaction by fructose, as well as that by glucose, in control and diabetic rat lens was analyzed by using antibodies which specifically recognize adducts of lysine with fructose and with glucose. Levels of fructose adducts in diabetic rat lens were 2.5 times that of the control, and correlated with sorbitol levels. This was mainly due to enhanced glycation of beta- and gamma-crystallins by fructose under diabetic conditions. These data suggest that glycation by fructose may also play a role in cataract formation under conditions of diabetes and aging.

Animals↗
PubMed1998

Purification and characterization of UDP-GlcNAc:Galbeta1-4GlcNAcbeta1-3*Galbeta1-4Glc(NAc)-R(GlcNAc to *Gal) beta1,6N-acetylglucosaminyltransferase from hog small intestine.

A beta1,6N-acetylglucosaminyltransferase (beta1-6GnT) responsible for the formation of the beta1,6-branched poly-N-acetyllactosamine structure has been purified 210,000-fold in 2.4% yield from a homogenate of hog small intestine by successive column chromatographies involving CM-Sepharose FF, Ni2+-chelating Sepharose FF, and UDP-hexanolamine-agarose, using an assay wherein pyridylaminated lacto-N-neotetraose (Galbeta1-4GlcNAcbeta1-3Galbeta1-4Glc-PA) was used as an acceptor substrate, and the reaction product was Galbeta1-4GlcNAcbeta1-3(GlcNAcbeta1-6)Galbeta1-4 Glc-PA. The apparent molecular weight of the purified enzyme was 76,000 under nonreducing conditions. The enzyme has a pH optimum at 7.0 and has no requirement for any divalent metal ions. The Km values for pyridylaminated lacto-N-neotetraose and UDP-GlcNAc were 0.96 and 2. 59 mM, respectively. For its activity, this enzyme was shown to have an absolute requirement of at least a complete LacNAc (LacNAc = Galbeta1-4GlcNAc) residue bound to position 3 of the acceptor Gal residues, i.e. it is capable of acting only on the Gal residues of internal LacNAc units. The data strongly suggest that this enzyme could be involved in generating branches to central positions of preformed as well as growing polylactosamine chains, but not in synthesizing the distal branches to growing polylactosamine chains.

Amino Sugars↗
PubMed1998

Analysis of human herpesvirus 6 U3 gene, which is a positional homolog of human cytomegalovirus UL 24 gene.

The US22 gene family was first discovered in human cytomegalovirus (HCMV) and contains several conserved amino acid motifs. Human herpesvirus 6 (HHV-6) also encodes several genes belonging to the US22 family, including the U3 gene (a positional homolog of HCMV UL24). Because the gene products of the US22 gene family function as gene regulators in general, we analyzed the HHV-6A U3 gene. Six transcripts with different molecular weights of 7.5-1.8 kb were detected by Northern blot analysis using a U3-specific probe. Sequence analyses of the respective cDNA clones and primer extension experiments revealed that the U3 gene encoded the 2.0- and 3.5-kb transcripts and had no splicing within the U3 gene region. By immunofluorescence testing using antibodies raised to a fusion protein of MBP (maltose-binding protein) and U3, the U3 viral antigen was detected as early as 24 h p.i. in HHV-6A-infected U373 cells. The antigens were found in cytoplasmic granules, preferentially in the endoplasmic reticulum. Moreover, cotransfection assay using a luciferase gene expression system revealed that the U3 gene product was capable of activating the human immunodeficiency virus long terminal repeat promoter in CV1 cells.

Cytomegalovirus↗
PubMed1998

Analysis of extracellular matrix synthesis during wound healing of retinal pigment epithelial cells.

To investigate changes in retinal pigment epithelial (RPE) cells during wound healing, we evaluated the deposition of newly synthesized extracellular matrix (ECM) over time during wound healing in rat RPE cultures. We also estimated the effect of growth factors on the healing rate and ECM synthesis. After preparing rat RPE cell sheet cultures, we made round 1-mm defects in the cultures. Fibronectin, laminin, and collagen IV synthesis were evaluated with immunocytochemistry every 12 hours after wounding. S-phase cell distribution was analyzed every 12 hours by 5-bromodeoxyuridine uptake. We added either platelet-derived growth factor (PDGF), epidermal growth factor (EGF), or transforming growth factor- beta2 (TGF-beta2) to cultures at concentrations of 1, 10, and 100 ng/mL and immunocytochemically analyzed the effects on ECM and estimated the rate of wound closure. Although approximately 50% closure was achieved 24 hours after wounding, fibronectin deposits first appeared at that time. Laminin and collagen IV were first detected at 36 hours and fibronectin staining had extended toward the wound center. S-phase cells were distributed in concentric rings that moved centripetally over time and corresponded to the leading edge of the area stained with anti-ECM antibodies. TGF-beta2 enhanced ECM deposition, but EGF and PDGF did not. TGF-beta2 decreased the healing rate in a dose-dependent manner, whereas PDGF promoted wound closure. EGF enhanced closure at the highest concentration only. In summary, wound healing in RPE may be initiated when cells at the wound edge slide or migrate toward the wound center, which is followed by cell proliferation and then ECM synthesis. ECM components may be produced in a specific sequence during healing. TGF-beta2 may promote RPE cell differentiation, and PDGF may enhance proliferation during wound healing of the RPE.

Animals↗
PubMed1998

Pneumatic displacement of subretinal hemorrhage without tissue plasminogen activator.

OBJECTIVE: To assess the efficacy and complications of intravitreal injection of perfluoropropane gas for displacement of subretinal hemorrhage (SRH), without the use of tissue plasminogen activator. PATIENTS AND METHODS: Pure perfluoropropane gas (0.4-0.5 mL) was injected into the vitreous cavity in 5 patients with SRH involving the fovea because of age-related macular degeneration (4 eyes) or ruptured retinal arterial macroaneurysm (1 eye). The patients were instructed to maintain a prone position. RESULTS: Visual acuity ranged from 20/300 to 20/2000 before gas injection. On the day after gas injection, SRH was dramatically displaced in 3 eyes and slightly displaced with a reduction in the thickness of subfoveal hemorrhage in the remaining 2 eyes. Final visual acuity improved in all cases, ranging from 20/15 to 20/220. Three eyes had a final visual acuity of 20/50 or better. Vitreous hemorrhage caused by migration of SRH into the vitreous cavity and retinal detachment each occurred in 1 eye, and both complications were successfully treated by vitrectomy. CONCLUSIONS: Gas injected into the vitreous cavity can displace SRH without the use of tissue plasminogen activator in some cases. Visual acuity after gas injection may be improved, making this treatment an alternative to evacuation of SRH with vitrectomy.

Aged↗
PubMed1998

Estimation of the neurovirulence of poliovirus by non-radioisotope molecular analysis to quantify genomic changes.

Mutant analysis by polymerase chain reaction and restriction enzyme cleavage (MAPREC) has been developed for poliovirus to determine quantitatively for the presence of genomic changes in particular nucleotide sequences correlate with the characteristic of neurovirulence for monkeys. Currently the MAPREC is scheduled to be used as a routine safety test for oral poliomyelitis vaccine (OPV). Radioisotopes (RI) are used in MAPREC for quantitative determinations, a circumstance likely to limit its use. We investigated the possibility of developing a modified MAPREC, which did not require the use of radioisotopes, and developed a procedure designated NON-RI MAPREC. Conventional MAPREC and NON-RI MAPREC were then used in a series of studies in which analyses were performed on Sabin type 1 and Sabin type 3 attenuated vaccine polioviruses prepared under various conditions. Under the experimental conditions used, the stability of the genome of type 1 virus was shown to be markedly greater than that of the type 3 virus, and the frequency of mutants was observed to vary in relation to both the virus strain and the virus inoculum used. The results of the studies relating to the two analytical procedures used indicated that the reproducibility of both methods was of a similarly high order, but that MAPREC had a somewhat broader range of sensitivity than NON-RI MAPREC. As the quantity of genomic changes in OPV relating to neurovirulent properties are within the range of detection by NON-RI MAPREC, this procedure can be used as a quality control test for OPV.

Animals↗
PubMed1998

Novel polymorphisms in the beta ig-h3 gene.

We found three novel polymorphisms in the beta ig-h3 gene in patients with gelatinous drop-like corneal dystrophy: (1) a substitution from CTC to CTT at codon 472 that did not alter an amino acid; (2) a substitution from GCG (Ala) to GTG (Val) at codon 480; and (3) a substitution from C to T in intron 10, three nucleotides upstream from the acceptor site of exon 11. The allelic frequencies of the C:T polymorphism at codon 472 and in intron 10 in the Japanese population were estimated to be 0.778:0.222 and 0.954:0.046, respectively. Although the codon 480 substitution was not observed in 54 unrelated healthy Japanese people, the substation did not co-segregate with the disease phenotype, suggesting that this was a rare, non-deleterious alteration.

Corneal Dystrophies, Hereditary↗