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Y Mashima

Publications and source records attributed to Y Mashima.

At least 19 recordsLinked to original sources
PubMed2002

Corneal electrolysis for recurrence of corneal stromal dystrophy after keratoplasty.

AIMS: To evaluate corneal electrolysis as a treatment for recurrent diffuse corneal opacities at the host-graft interface of the stroma or at the subepithelial region in two types of granular corneal dystrophy (GCD). METHODS: Recurrence developed at the host-graft interface of the stroma after lamellar keratoplasty in a patient with Avellino corneal dystrophy (ACD). At surgery, the deep aspect of the graft in this patient was partially separated from host tissue to expose the deposits, with one third of the host-graft junction left intact. The graft was everted, and electrolysis was applied directly to remove the deposits attached to both surfaces of the host and the graft. Then the graft was returned to its place and sutured. In two patients with homozygous ACD and one patient with the superficial variant of GCD, diffuse subepithelial opacities developed following penetrating keratoplasty. Electrolysis was applied directly to the corneal surface. RESULTS: Deposits at the host-graft interface of the stroma and in the subepithelial region disappeared following treatment, and vision recovered in all patients. CONCLUSIONS: This method is a simple, easy, and inexpensive way to remove deposits that recur after lamellar or penetrating keratoplasty.

Aged↗
PubMed2001

Microcirculation in the macular area of eyes with an idiopathic epiretinal membrane.

PURPOSE: To measure the microcirculation in the macula area of eyes before and after the removal of an idiopathic epiretinal membrane (ERM) by vitreous surgery. METHODS: Tissue blood flow in the macula was examined with the Heidelberg retina flowmeter in 12 eyes with an ERM before and 3, 6, and 12 months after vitrectomy. Blood flow measurements were performed in a 10 x 5 degree area in the macula that was divided into superior and inferior areas. At least three measurements were obtained, and the mean blood flow (MBF) was calculated by scanning laser Doppler flowmetry. The ratio of the MBF in the affected eye to that in the fellow eye was used for statistical analysis. RESULTS: The ratios of the MBF in the affected to the fellow eye in the superior area before and 1, 3, 6, and 12 months after surgery were 0.73, 0.51, 0.77, 0.88, and 1.01, respectively. The ratios of the MBF in the inferior area for the same periods were 0.70, 0.52, 0.75, 0.83, and 0.98, respectively. CONCLUSIONS: Eyes with an ERM showed abnormal hemodynamics in the macula that gradually improved after vitrectomy to a status comparable with the MBF of the normal fellow eye.

Adolescent↗
PubMed2001

On- and off-responses of the photopic electroretinograms in X-linked juvenile retinoschisis.

PURPOSE: To examine the physiologic condition of the middle retinal layer of patients with X-linked juvenile retinoschisis (xlRS) by studying the on- and off-responses of the photopic electroretinograms (ERGs). METHODS: Eleven unrelated Japanese men (mean age; 24.9 +/- 7.6 years) who were clinically diagnosed with xlRS and molecularly confirmed as having XLRS1 mutations were investigated. For the photopic ERGs, the a-, b- and d-wave amplitudes elicited by long duration stimuli were recorded, and the responses from the xlRS patients were compared to those recorded from normal subjects (n = 14, mean age, 27.5 +/- 4.5 years). We also examined the relationship between the photopic ERG responses and the genotype. RESULTS: No significant difference was found between the a- and d-wave amplitudes in the xlRS patients (34.2 +/- 8.7 microV, 52.5 +/- 10.4 microV, respectively), and those in normal subjects (40.4 +/- 10.3 microV, 44.7 +/- 6.3 microV, respectively). The mean b-wave amplitude in the xlRS patients was significantly smaller (10.5 +/- 7.7 microV) than the mean of normal subjects (46.4 +/- 10.2 microV) (P < 0.0001). No significant correlation was found between the ERG responses and the locus of the mutation. CONCLUSION: The photopic ERG demonstrated considerable impairment of the on-pathway arising from an abnormality of the on-bipolar cells or possibly secondary to Müller cell abnormality in xlRS.

Adolescent↗
PubMed2001

Fat adherence syndrome after retinal surgery treated with amniotic membrane transplantation.

PURPOSE: We present favorable results with amniotic membrane transplantation in a patient who developed fat adherence syndrome after retinal surgery. DESIGN: Interventional case report. METHODS: A 37-year-old man had diplopia resulting from hypotropia of the left eye after retinal detachment surgery. Removal of a previously implanted silicon sponge had little effect because of fibrous adhesion between the inferior rectus muscle and adjacent periorbital fat. We performed amniotic membrane transplantation combined with conventional extraocular muscle surgery. RESULTS: Postoperatively, supraduction of the left eye became almost full. The field of binocular vision was extended markedly by treatment, both in the primary position and with downward gaze. These improvements remained stable over 1 year of follow-up. CONCLUSION: Amniotic membrane transplantation appears to be effective for preventing regrowth of restrictive scar tissue in the fat adherence syndrome.

Adipose Tissue↗
PubMed2001

Clinical application of the multifocal VEPs.

PURPOSE: To determine whether visual field defects can be detected by the multifocal VEP technique. METHODS: Multifocal VEPs were elicited by a pseudorandom binary m-sequence stimulus (VERIS II). The stimulus was a dartboard-like pattern of 61 sectors, and the luminance of each sector alternated between white and black. The stimulus area subtended approximately 25 degrees. Each recording was divided into 8 equal segments, and the total recording time was about 4 min. Multifocal VEPs were recorded from 25 normal subjects and six patients with visual field loss. The responses summed within 4 quadrants were used in the analysis and were compared with the visual fields obtained by perimetry. RESULTS: In six perimetrically-documented visual field defects, the responses summed over each quadrant of the field were reduced in the corresponding affected quadrants. In addition, recovery of the visual field loss following treatment was accompanied by a recovery of the responses. CONCLUSIONS: Multifocal VEPs summed within four quadrants can be used for an objective evaluation of the visual fields. The testing can be obtained in 4 min with no pain or discomfort to the patient.

Adult↗
PubMed2001

Phenotype associated with an R120X nonsense mutation in the RP2 gene in a Japanese family with X-linked retinitis pigmentosa.

We examined a Japanese family with X-linked retinitis pigmentosa (RP) associated with a nonsense mutation, R120X, in the RP2 gene. The 26-year-old proband presented at the age of seven years with a two-year history of night blindness. Visual disability worsened with increasing age. At age 24, visual acuity was 0.08 in both eyes. Testing for refractive error indicated mild myopia. Visual fields showed bilateral-constriction to 10 degrees. He had central macular areolar sclerosis in both eyes. Two maternal uncles had vision of light perception to hand movement in their early forties together with dense bilateral cataracts. The ocular phenotype of this family with R120X was considered severe; reported phenotypes associated with this mutation have not been uniform.

Amino Acid Sequence↗
PubMed2001

Successful treatment of dry eye in two patients with chronic graft-versus-host disease with systemic administration of FK506 and corticosteroids.

PURPOSE: We present two cases of severe dry eye in patients with chronic graft-versus-host disease (CGVHD) after hematopoietic stem cell transplantation (SCT) who were successfully treated by the systemic administration of FK506 and corticosteroids. METHODS AND RESULTS: A 29-year-old man with chronic myelogenous leukemia underwent SCT. Oral and lung CGVHD developed on approximately day 130, and dry eye associated with CGVHD was diagnosed on day 168. The patient began receiving cyclosporin A (150 mg/d) for the treatment of oral and lung CGVHD. Treatment with prednisolone (1 mg/kg/d) began on approximately day 300. Oral and lung GVHD improved slightly, but worsened again although systemic administration of cyclosporin A and prednisolone were continued. Cyclosporin A was discontinued, and systemic administration of FK506 was started on day 376. Forty-four days later, marked improvement in the ocular surface and other organs was observed. However, the dry eye worsened while tapering FK506, with no flare of other affected organs. A 43-year-old woman with myelodysplastic syndrome underwent SCT. She received FK506 for prophylaxis of CGVHD. She had mild dry eye before SCT. Oral and intestinal CGVHD developed, and the dry eye worsened significantly on approximately day 150 while tapering FK506. Treatment with prednisolone (1 mg/kg/d) began, and the dose of FK506 was increased. By day 240, the symptoms of dry eye and the findings of the ocular surface markedly improved, and CGVHD in other organs was completely resolved. However, the improvement in the dry eye was lost when FK506 was tapered for the second time. CONCLUSION: Systemic administration of FK506 with corticosteroids is an effective treatment of severe dry eye in patients with CGVHD, but long-term administration may be required to achieve a lasting response. These cases also suggest that further investigation into the use of topical FK506 and prednisolone as a maintenance therapy should be pursued.

Adult↗
PubMed2001

A significant role of stromal fibroblasts in rapidly progressive dry eye in patients with chronic GVHD.

PURPOSE: To elucidate histopathologic features of the lacrimal gland in chronic graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation. METHODS: Lacrimal gland specimens from five patients who had dry eye as part of the symptoms of chronic GVHD were examined by immunohistochemistry and transmission electron microscopy. Lacrimal gland specimens from five patients with Sjögren's syndrome (SS) were used as control samples. RESULTS: Lymphocytes, predominantly T cells, were found primarily in the periductal areas of the lacrimal gland from patients with chronic GVHD, whereas B cells were the dominant infiltrating cells in the acinar areas of the lacrimal gland from patients with SS. Notable findings in the lacrimal gland from patients with chronic GVHD were marked fibrosis of the glandular interstitium and an increase in the number of CD34(+) stromal fibroblasts. These findings were more prominent in patients with severe dry eye than in those with mild dry eye. Electron microscopic observations of the lacrimal gland from patients with chronic GVHD revealed that stromal fibroblasts were attached to various inflammatory cells, especially T cells, through primitive or rudimentary contacts. In addition, the presence of a well-developed rough endoplasmic reticulum in the fibroblasts and newly synthesized collagen fibrils in the extracellular matrix indicated an active production of extracellular matrix components. Electron micrographs revealed multilayered and thickened basal laminae of blood vessels, ducts, and lobules in the lacrimal gland of patients with chronic GVHD; however, these observations were infrequently observed in the lacrimal glands of patients with SS. CONCLUSIONS: The results suggest substantial differences in the lacrimal gland histopathology of patients with chronic GVHD and SS. In addition, it is likely that stromal fibroblasts are actively involved in the pathogenic process of chronic GVHD in the lacrimal gland by producing excessive extracellular matrix components.

Adult↗
PubMed2001

[Two cases of digitalis toxicity with reversible and severe decrease of visual acuity].

BACKGROUND: We performed electrophysiologic tests on two patients with digitalis toxicity who first had photophobia and xanthopsia and revealed reversible reduced visual acuity and binocular central scotoma. CASES: The patients were a 72-year-old male and a 54-year-old male who had symptoms of digitalis toxicity. FINDINGS: The corrected visual acuity was severely decreased during digitalis toxicity, 0.02 oculus dexter (OD) and 0.1 oculus sinister (OS) in case 1 and 0.04 OD and 0.2 OS in case 2. But visual acuity recovered as the blood levels of digitalis decreased to the normal level and the corrected visual acuity was 0.7 OD and 0.8 OS in case 1 and 0.8 OD and 0.9 OS in case 2. We recorded 30 Hz-flicker electroretinogram (ERG), single flash ERG, photopic ERG, and scotopic ERG when digitalis blood levels were elevated and normal. Decreased amplitudes of 30 Hz-flicker ERG and photopic ERG suggested that photoreceptor function was disturbed at digitalis toxicity and cone dysfunction was more severely disturbed than rod dysfunction. CONCLUSION: 30 Hz-flicker ERG, as well as electrocardiogram and digitalis blood level, is a relatively convenient and useful measure of digitalis toxicity. It is necessary consiler toxicity when severe visual dysfunction is observed in patients with digitalis therapy.

Aged↗
PubMed2001

[Objective evaluation of visual field loss in a patient with branch retinal artery occlusion and brain infarction].

PURPOSE: To evaluate visual field loss using multifocal ERG(m-ERG), multifocal VEP(m-VEP), and Heidelberg Retina Flowmeter(HRF) in a patient with branch retinal artery occlusion(BRAO) and brain infarction. CASE: A 38-year-old man noticed inferior-nasal visual field loss in the left eye, and was referred to Keio University Hospital. He suffered from paralysis in the left leg due to brain infarction at the age of 24. However, he had not noticed visual field loss due to the brain infarction. His left fundus showed retinal edema in the area of a superior-temporal retinal artery occulusion. He was diagnosed as having BRAO. The Goldmann and Humphry perimetric examinations revealed homonymous quadrantanopia in the upper left field as well as inferior visual field defect in the left eye. RESULTS: Both m-ERG and m-VEP, especially second-kernel responses, were reduced in the affected retinal area of BRAO. But only m-VEP was affected in the corresponding area of homonymous quadrantanopia in the upper left field. The retinal flow in the area with BRAO evaluated by HRF was decreased in some areas and not in others, suggesting that retinal function was not necessarily consistent with retinal circulation. CONCLUSIONS: m-ERG and m-VEP are useful To differentiate retinal lesions from brain lesions in visual field loss.

Adult↗
PubMed2001

Novel cytochrome P4501B1 (CYP1B1) gene mutations in Japanese patients with primary congenital glaucoma.

PURPOSE: To investigate CYP1B1 gene mutations in Japanese patients with primary congenital glaucoma (PCG). METHODS: Sixty-five unrelated Japanese patients with PCG were screened by PCR-single-strand conformational polymorphism (SSCP) analysis followed by direct sequencing. No patients were offspring of consanguineous marriages, a common occurrence among patients in previous reports. PCG haplotypes were constructed with intragenic polymorphisms in affected individuals. Three-dimensional atomic structures of human CYP1B1 and four mutant CYP1B1 sequences representing missense mutations were assembled using homology modeling and were regularized by an energy-minimization procedure. RESULTS: Eleven novel mutations, including seven definite and four probable mutations, were detected in 13 (20%) of the 65 unrelated patients. Of the seven definite mutations, three were predicted to truncate the CYP1B1 open reading frame. The other four were missense mutations (Asp192Val, Ala330Phe, Val364Met, and Arg444Gln), all located in conserved core structures determining proper folding and heme-binding ability of cytochrome P450 molecules. Molecular modeling demonstrated that two of four mutations in positions 330 and 364 were structurally neutral, but Arg444Gln caused significant structural change. Of the four probable mutations, three were missense (Val198Ile, Val320Leu, and Glu499Gly); the other was a base substitution in the noncoding region of exon 1. CONCLUSIONS: The 11 varied CYP1B1 mutations found in 13 unrelated Japanese patients with sporadic occurrence of PCG represent an allelic heterogeneity and may be unique to a specific population.

Amino Acid Sequence↗
PubMed2001

[DNA diagnosis of Leber's hereditary optic neuropathy performed at Keio University Hospital].

PURPOSE: To learn the clinical value of DNA diagnosis for Leber's hereditary optic neuropathy (LHON), we reviewed the results of DNA diagnosis performed at Keio University Hospital. METHODS AND PATIENTS: Included were 224 patients, 87 patients at Keio University Hospital and 137 patients from other clinics, with bilateral optic neuropathy who were suspected of having LHON. With informed consent, the 3460, 9804, 11,778, 13,730, and 14,484 mutations of mitochondria DNA (mt-DNA) were examined form 1990 to 1998. Percentage of male patients, age at onset of the disease, and percentage of familial history were compared between patients with and without the mutations. The clinical diagnosis at the time of DNA analysis were examined in patients without the mutation. RESULTS: Seventy two(32%) of the 224 patients had one of the five mtDNA mutations, 63(88%) patients had the 11,778 mutation, 6(8%) had the 14,484 mutation, and 3(4%) had the 3460 mutation. In 72 patients with one of the LHON mutations, 89% of the patients were male, the average age of the disease onset was 24.3 years, and 42% of the patients had a familial history of the disease. Eighty (53%) of 152 patients who did not have one of the 5 mutations were diagnosed as having bilateral optic atrophy with unknown causes. CONCLUSION: Although DNA diagnosis of LHON is a useful clinical test, we must know the clinical characteristics of the disease, before taking advantage of this analysis.

Adult↗
PubMed2001

[Autosomal dominant inherited corneal dystrophies associated with TGFBI mutation].

BACKGROUND: Mutations of the transforming growth factor beta-induced (TGFBI) gene whose product is called keratoepithelin (KE) have been identified in 4 major autosomal dominantly inherited corneal dystrophies. The purpose of this study was to identify the mutations in Japanese patients with these dystrophies, and to investigate the nature of corneal deposits. METHOD: Mutations of the TGFBI gene were screened by polymerase chain reaction (PCR) followed by direct sequencing of the PCR products in Japanese patients clinically diagnosed as having granular corneal dystrophy, Avellino corneal dystrophy, lattice corneal dystrophy, and Reis-Bücklers' dystrophy. Corneal specimens obtained from corneal transplants were analyzed by histochemistry (Masson trichrome and Congo red stains), immunohistochemistry, and western blotting using anti KE antibody. I reviewed papers about TGFBI gene mutations previously published. RESULTS: The genotype/phenotype relationship of corneal dystrophies associated with mutations of the TGFBI gene is markedly evident. Avellino corneal dystrophy associated with the R 124 H mutation was the most common form of corneal stromal dystrophy in Japan. In Japan this dystrophy has been called granular corneal dystrophy up to now. Thiel-Behnke dystrophy (R 555 Q) has been also misdiagnosed as Reis-Bücklers' dystrophy. The original Reis-Bücklers' dystrophy is associated with R 124 L, which is compatible with superficial granular corneal dystrophy. Corneal deposits were associated with TGFBI products whose sizes were specific for their mutations. CONCLUSIONS: Mutations of the gene resulted in different types of KE aggregation accompanied with characteristic changes of processing and metabolism. The classification of these diseases according to genetic pathogenesis may be more appropriate than the use of clinical or histological findings.

Corneal Dystrophies, Hereditary↗
PubMed2000

Myocilin expression in the astrocytes of the optic nerve head.

We investigated the expression of myocilin in the optic nerve head of porcine eyes by Western blotting and immunohistochemical staining. Myocilin was localized in the nucleus, centrosome, glial filament, mitochondria, and some parts of the cell membranes of the astrocytes. Myocilin was also detected at the edge-feet portion of the processes of astrocytes adjacent to the inner limiting membrane and blood vessel wall. The astrocytes are the major cell population in the optic nerve head, contributing to the architecture of the nerve axon and blood vessels. Therefore, myocilin gene mutation and change of myocilin protein are likely to affect the architecture of the optic nerve head and induce various forms of glaucomatous optic nerve damage.

Animals↗
PubMed2000

Amyloid and non-amyloid forms of 5q31-linked corneal dystrophy resulting from kerato-epithelin mutations at Arg-124 are associated with abnormal turnover of the protein.

Mutations in kerato-epithelin are responsible for a group of hereditary cornea-specific deposition diseases, 5q31-linked corneal dystrophies. These conditions are characterized by progressive accumulation of protein deposits of different ultrastructure. Herein, we studied the corneas with mutations at kerato-epithelin residue Arg-124 resulting in amyloid (R124C), non-amyloid (R124L), and a mixed pattern of deposition (R124H). We found that aggregated kerato-epithelin comprised all types of pathological deposits. Each mutation was associated with characteristic changes of protein turnover in corneal tissue. Amyloidogenesis in R124C corneas was accompanied by the accumulation of N-terminal kerato-epithelin fragments, whereby species of 44 kDa were the major constituents of amyloid fibrils. R124H corneas with prevailing non-amyloid inclusions showed accumulation of a new 66-kDa species altogether with the full-size 68-kDa form. Finally, in R124L cornea with non amyloid deposits, we found only the accumulation of the 68-kDa form. Two-dimensional gels revealed mutation-specific changes in the processing of the full-size protein in all affected corneas. It appears that substitutions at the same residue (Arg-124) result in cornea-specific deposition of kerato-epithelin via distinct aggregation pathways each involving altered turnover of the protein in corneal tissue.

Amyloid↗
PubMed2000

Novel mutations in the myocilin gene in Japanese glaucoma patients.

Myocilin is a gene responsible for juvenile onset primary open angle glaucoma (POAG) mapped as the GLC1A locus and, many mutations have been reported worldwide. Some mutations were found not only in patients with juvenile onset POAG, but also in patients with late onset POAG and in patients with normal tension glaucoma. To investigate the mutation prevalence in Japan, we performed a mutation analysis in 140 unrelated Japanese patients. We have identified the 10 sequence variants, of which four were highly probable for disease-causing mutations (Arg46ter, Arg158Gln, Ile360Asn, and Ala363Thr), and six polymorphisms (Gln19His, Arg76Lys, Asp208Glu, Val439Val, Arg470His, and Ala488Ala). Thus, myocilin mutations were found at the rate of 4/140 (2.9%) probands, similar to previous reports with other ethnic populations.

Adult↗
PubMed2000

Decreased substance P concentrations in tears from patients with corneal hypesthesia.

PURPOSE: To determine whether substance P concentrations in tears reflect corneal hypesthesia. METHODS: Sixteen patients with unilateral corneal hypesthesia participated in this study. Unstimulated tears were collected from each eye of all subjects. Substance P concentrations in tears were measured by an enzyme immunoassay system. RESULTS: Substance P concentrations in tears from the affected eye were lower than those in tears from the unaffected eye in all subjects. The mean concentration of substance P in tears from affected eyes was 197.7 +/- 69.5 pg/mL, markedly lower than those from unaffected eyes (333.2 +/- 74.6 pg/mL). CONCLUSION: Substance P concentrations in tears, which are thought to reflect the neuropeptides levels in ocular tissues, can be used as an indicator of corneal denervation.

Adult↗