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Biomedical subjects

Itaru Kimura

Publications and source records attributed to Itaru Kimura.

At least 19 recordsLinked to original sources
PubMed2006

Relaxation of encircling buckle improved choroidal blood flow in a patient with visual field defect following encircling procedure.

BACKGROUND: We report a patient with a visual field defect after retinal reattachment by the encircling procedure for rhegmatogenous retinal detachment. We confirmed improved ocular blood flow after relaxation of the buckle. CASE: A 24-year-old woman with a visual field defect appearing after an encircling procedure for rhegmatogenous retinal detachment. OBSERVATIONS: Before and after relaxing the encircling buckle, we measured tissue blood flow in the fundus of each eye of the patient using a Heidelberg retina flow meter. Preoperative measurements showed a reduction of blood flow at the disc rim in the diseased fundus, while retinal blood flow was not reduced (P = 0.026, disc rim area versus retinal area, one-factor analysis of variance, ANOVA). Indocyanine green angiography showed extensive peripheral filling delay. Electroretinography showed low a-wave and b-wave amplitudes, but normal oscillatory potential. The base value of the electro-oculogram was severely reduced in the right eye. The blood flow values after surgery indicated a significant improvement of blood flow (P = 0.01, one-factor ANOVA). No further progression in the visual field defect was observed, and visual acuity of the right eye improved from 0.8 to more than 1.0. CONCLUSIONS: These results suggest that the choroidal circulation disturbance, which was found after the encircling procedure, had a plausible role in the development of the visual field defect.

Adult↗
PubMed2006

Discordance between subjective perimetric visual fields and objective multifocal visual evoked potential-determined visual fields in patients with hemianopsia.

PURPOSE: To investigate the concordance between subjectively and objectively acquired visual fields in patients with subjectively determined hemianopsia. DESIGN: Retrospective observational study. METHODS: Ten patients, six men and four women, ranging in age from 28 to 68 years, were studied. Goldmann or Humphrey perimeters were used to obtain the subjectively determined visual fields for up to 25 degrees of eccentricity, and the VERIS Scientific System (Electro-Diagnostic Imaging, San Francisco, California, USA) was used to record multifocal visual evoked potential [VEPs] (mfVEPs) to obtain the objective visual fields. Each of the 60 black-and-white segments of the checkerboard stimulus was alternated according to a binary m sequence. The first slices of the second-order kernels were extracted and analyzed. RESULTS: In five cases, the visual field loci where the mfVEPs were within normal limits corresponded to the scotomatous areas obtained by conventional perimetry. In these discordant cases, the lesions (e.g., arteriovenous malformation) were located in the occipital lobe. Two of these cases had a complete recovery of the subjective visual field. The lesions of the concordant cases were located outside the occipital lobe (e.g., pituitary adenoma). In these cases, no visual field improvement was seen. The temporal crescent syndrome was ruled out in patients with posterior lesions by computed tomography (CT) or magnetic resonance imaging (MRI) findings. CONCLUSIONS: In some patients with occipital lesions, the subjective and objective visual field results are discordant, and some of them will show a recovery of the visual field deficits.

Adult↗
PubMed2006

A case of dysferlinopathy presenting choreic movements.

Mutations in the dysferlin gene cause limb-girdle muscular dystrophy type 2B (LGMD2B). The involvement of the central nervous system in dysferlinopathy has not been described. We describe the clinical features of a patient with LGMD2B associated with dysferlin mutations (homozygous G3370T) who presented progressive choreic movements. The patient had no evidence of other causes of chorea. It is suggested that the chorea may be associated with the altered expression of the brain isoform of dysferlin.

Brain↗
PubMed2006

Microcirculation at optic disc rim is correlated with visual field defects in cases of anterior ischaemic optic neuropathy.

We report two cases of anterior ischaemic optic neuropathy in whom tissue blood flow at the disc rim was correlated with the visual field defect. Tissue blood flow of each eye was evaluated with Heidelberg retina flowmeter. Both cases experienced acute visual loss and an altitudinal hemianopsia associated with optic disc oedema in the affected eye. In each case, the tissue blood flow at the affected (upper or lower half) disc rim corresponding to visual field deficit was reduced compared with that at the opposite-sided half disc rim in the affected eye and with the corresponding area in the fellow eye. The reduction of blood flow in the affected half disc rim associated with the visual field defect demonstrated that retina flowmetry can detect differences in tissue blood flow between superior and inferior sectional disc rim areas as well as between eyes non-invasively.

Blood Flow Velocity↗
PubMed2005

Decreased blood flow at neuroretinal rim of optic nerve head corresponds with visual field deficit in eyes with normal tension glaucoma.

PURPOSE: To determine the relationship between the blood flow parameters of the optic disc rim and the glaucomatous visual field changes. DESIGN: Observational cross-sectional study. METHODS: Tissue blood flow in the neuroretinal rim within the optic disc was determined with the Heidelberg retina flowmeter(HRF) in 54 eyes of 54 patients with normal tension glaucoma (NTG). Patients were selected whose visual field defects were confined to either the superior or inferior hemifield. Blood flow measurements were made in a 10 degrees x 2.5 degrees area of the superior and inferior neuroretinal rim within the optic disc. The mean blood flow (MBF) was calculated by the automatic full-field perfusion image analyzer program, and the ratio of the MBF in the superior to the inferior rim areas (the S/I ratio) was calculated from the same HRF image in order to minimize the variation of measurement condition. RESULTS: Inferior rim blood flow is less than superior rim blood flow in patients with superior hemifield defect, and superior rim blood flow is reduced compared to inferior in patients with inferior hemifield defect. The mean S/I ratios of the MBF in the patients with superior hemifield defect (1.46, n=37) was significantly higher than that in the patients with inferior hemifield defect (0.79, n=17; P<0.0001, Mann-Whitney U-test). CONCLUSIONS: The blood flow in the neuroretinal rim was found to correspond to the regional visual field defect in eyes with NTG. Reductions in flow were associated with reductions in function.

Adult↗
PubMed2005

Association between glaucoma and gene polymorphism of endothelin type A receptor.

PURPOSE: Endothelin 1 (ET-1), a potent vasoconstrictor, may affect regulation of intraocular pressure and ocular vessel tone. Thus, ET-1 and its receptors may contribute to development of glaucoma. We investigated whether gene polymorphisms of ET-1 (EDN1) and its receptors ETA (EDNRA) and ETB (EDNRB) were associated with glaucoma phenotypes and clinical features. METHODS: We studied 224 normal Japanese controls and 426 open angle glaucoma (OAG) patients including 176 with primary open angle glaucoma (POAG) and 250 with normal tension glaucoma (NTG). Nine single nucleotide polymorphisms were detected among the participants using the Invader assay; four for EDN1 (T-1370G, +138/ex1 del/ins, G8002A, K198N), four for EDNRA (G-231A, H323H, C+70G, C+1222T), and one for EDNRB (L277L). Genotype distributions were compared between normal controls and OAG. Age at diagnosis, untreated maximum intraocular pressure (IOP), and visual field defects at diagnosis were examined for association with polymorphisms. RESULTS: Of the 9 polymorphisms, genotype distributions showed no significant differences between OAG patients and controls adjusted by age. The GG genotype of EDNRA/C+70G was associated with worse visual field defects in NTG patients (p=0.014; Mann-Whitney U test, and p=0.027; logistic regression analysis). CONCLUSIONS: The polymorphism of EDNRA/C+70G may be related to NTG risk factors.

Aged↗
PubMed2005

Podoplanin as a marker for mesothelioma.

Podoplanin is a specific marker for lymph vessel endothelial cells. It was noted that podoplanin is expressed in reactive mesothelial cells. The utility of podoplanin for the histological diagnosis of tumors was then investigated, especially for mesothelioma. Immunohistochemical study of podoplanin was carried out in five malignant mesotheliomas and 118 other tumors including 93 adenocarcinomas, four squamous cell carcinomas, six gastrointestinal stromal tumors and five endocrine tumors. Immunoreactivity for podoplanin was demonstrated on the cell membrane of tumor cells for all mesotheliomas. All other tumors were negative for podoplanin. Among the many antibodies used for differential diagnosis of malignant mesothelioma, podoplanin has the potential to be an excellent tumor marker in both specificity and sensitivity. The utility of podoplanin as a marker for mesothelioma will be confirmed by further studies.

Adenocarcinoma↗
PubMed2005

Genetic polymorphisms in the angiotensin II receptor gene and their association with open-angle glaucoma in a Japanese population.

PURPOSE: The local renin-angiotensin system (RAS) is present in the ciliary body and plays a role in regulating aqueous humor dynamics and thus intraocular pressure (IOP). The purpose of this study was to determine whether gene polymorphisms in the RAS increase the risk of development of glaucoma in the Japanese. METHODS: A case-control study was performed in 698 Japanese subjects: 190 patients with primary open-angle glaucoma (POAG), 268 patients with normal-tension glaucoma (NTG), and 240 normal subjects. Ten polymorphisms in seven genes-AGT/Thr174Met and AGT/Met235Thr; REN/I8-83G-->A; ACE/insertion(I)-deletion(D); CMA/-1930A-->G; AGTR1/-731T-->G, AGTR1/-521C-->T, and AGTR1/1166A-->C; AGTR2/3123C-->A; and CYP11B2/-344T-->C were examined. The age, IOP, and visual field defects, all at diagnosis, were examined to determine whether they were associated with the polymorphisms. The effects of oral angiotensin II receptor blocker (ARB) on IOP were examined in association with the AGTR1 and AGTR2 polymorphisms in 20 normal subjects. RESULTS: Of the 10 polymorphisms, the AGTR2/3123C-->A polymorphisms had a significantly different distribution in female patients with NTG; the frequency of the CA+AA genotypes was significantly higher than in female control subjects (P = 0.0095 for CC versus CA+AA). Although no significant difference was seen in the clinical characteristics of female patients with NTG who carried the AGTR2/3123C-->A genotype, patients with CC in the AGTR2 gene had significantly worse visual field scores if they carried ACE/ID+DD (i.e., D carriers; P = 0.012). ARB significantly lowered IOP in normal subjects, but the male subjects with the AGTR2/3123A genotype had significantly less lowering of IOP than those with the C genotype (P = 0.014). CONCLUSIONS: Angiotensin II receptor gene polymorphisms may be associated with the risk of glaucoma in the Japanese population.

Administration, Oral↗
PubMed2004

Variants in optineurin gene and their association with tumor necrosis factor-alpha polymorphisms in Japanese patients with glaucoma.

PURPOSE: To investigate sequence variations in the optineurin (OPTN) gene and their association with TNF-alpha polymorphisms in Japanese patients with glaucoma. METHODS: The OPTN gene was analyzed in blood samples from 629 Japanese subjects. There were 194 patients with primary open-angle glaucoma (POAG), 217 with normal-tension glaucoma (NTG), and 218 with no eye disease (control subjects). The gene was screened for mutations by denaturing high-performance liquid chromatography. Genotyping of three polymorphisms of -308G-->A, -857C-->T, and -863C-->A in the TNF-alpha promoter region was performed. The associations between the genotypes and age, intraocular pressure (IOP), and visual field defects at the time of diagnosis were examined. RESULTS: A possible glaucoma-causing mutation, His26Asp, was identified in 1 of the 411 Japanese patients with glaucoma. A c.412G-->A (Thr34Thr) polymorphism in the OPTN gene was significantly associated with POAG (genotype frequency, P = 0.011; allele frequency, P = 0.003). The frequency of TNF-alpha/-857T and optineurin/412A carriers was significantly higher (P = 0.006) in patients with POAG than in control subjects. Among the patients with POAG who were carriers of TNF-alpha/-857T, the optineurin/412A carriers had significantly worse (P = 0.020) visual field scores than the non-optineurin/412A ones. The frequency of TNF-alpha/-863A and optineurin/603A (or Lys98) carriers was significantly higher in patients with POAG (P = 0.008) or NTG (P = 0.027) than in control subjects. Among the patients with POAG who were carriers of TNF-alpha/-863A, the ones with optineurin/603A (or Lys98) had significantly worse (P = 0.026) visual field scores than did those with non-optineurin/603A (or Lys98). CONCLUSIONS: These findings demonstrated that the OPTN gene is associated with POAG rather than NTG in the Japanese. Statistical analysis showed a possible interaction between polymorphisms in the OPTN and the TNF-alpha genes that would increase the risk for glaucoma.

Adult↗
PubMed2004

Field distribution of compound muscle action potentials of the calf muscles in rabbits.

The purpose of this study is to verify that compound muscle action potentials (CMAPs) generated a stationary potential and to examine extension of the CMAPs away from the stimulated muscle. A referential derivation and/or bipolar derivation to record the stationary potentials were carried out following tibial nerve stimulation at the popliteal fossa in 10 rabbits. After recording a bipolar and/or referential derivation, wave changes were monitored before and after severing the tibial nerve. The change of the wave by compressing or direct electrical stimulation to the calf muscle was also monitored. In referential derivatives, the stationary waves were observed on top of the skull in all the rabbits examined with the peak latency of the potentials from 3.78 msec to 5.04 msec. In bipolar derivations, the upper limits of the stationary waves recorded were the trunks. The peak latencies were from 2.35 msec to 5.46 msec with an average of 4.12 msec. By analyzing the results from severing the tibial nerves, compressing the calf muscles, and direct electrical stimulation of the calf muscle, the origin of these stationary potentials was determined to be CMAPs of the calf muscles. These findings suggest contamination of the stationary potentials originated by CMAPs for recording of any evoked potentials when motor nerves are stimulated.

Action Potentials↗
PubMed2004

[Long-term efficacy and safety of combined topical antiglaucoma therapy--timolol & unoprostone vs. betaxolol & unoprostone].

PURPOSE: To evaluate long-term efficacy and safety of treatment combining topical beta-blockers and isopropyl unoprostone in primary open-angle glaucoma and normal-tension glaucoma patients. METHODS: A prospective, open-label, parallel-group clinical comparison trial was performed to evaluate efficacy and safety of treatment combining 0.5% betaxolol and 0.12% isopropyl unoprostone (B&U) or 0.5% timolol and 0.12% isopropyl unoprostone (T&U). Forty eyes of 40 patients, which were matched in the aging and the stage of glaucomatous visual field defect, were studied. Twenty patients were treated with B&U and the other twenty patients with T&U twice daily for 24 months. Goldmann intraocular pressure(IOP), Humphrey automated perimetry, blood pressure, heart rate, and peak flow were done every six months in each group. RESULTS: In the B&U treatment group, mean IOP was 21.2 mmHg at baseline and 18.3 mmHg(p < 0.005) after 2 years, and in the T&U treatment group it was 21.1 mmHg at baseline and 17.9 mmHg (p < 0.001) after 2 years. The cases in which MD value decreased over 2 dB were one in the B&U treatment group and three in the T&U treatment group. The average MD value was significantly improved from -7.40 dB to -5.90 dB after 2 years with B&U treatment(p < 0.05), but there was no difference with the T&U treatment. None of the patients stopped combined therapy because of side effects, though heart rate was significantly reduced only in T&U treatment group. CONCLUSION: Both combined treatments were effective for IOP reduction in glaucoma patients, and the data from the B&U treatment group suggested that B&U was more effective in maintaining visual field than T&U.

Adult↗
PubMed2003

Optic disc excavation in the atrophic stage of Leber's hereditary optic neuropathy: comparison with normal tension glaucoma.

BACKGROUND: Abnormal optic disc excavations are reportedly seen in patients with Leber's hereditary optic neuropathy (LHON), a mitochondrial dysfunction disease. We examined the disc morphology in the eyes of patients with LHON at the atrophic stage and compared it to that in eyes with normal-tension glaucoma (NTG). METHODS: We studied 15 LHON patients with the 11778 mutation, 15 patients with NTG, and 25 normal subjects. The optic disc morphology was analyzed by Heidelberg retinal tomography (HRT). Ten parameters of the optic disc obtained by HRT were evaluated, including the diagnostic classification of glaucoma. RESULTS: Six of the nine morphological HRT parameters of the LHON patients, the exceptions being disc area, mean cup depth, and maximum cup depth, differed significantly from those of the normals. NTG patients had a significantly greater mean and maximum cup depth than LHON patients. The HRT glaucoma diagnostic software classified 22 (73%) of the 30 optic discs in LHON patients as glaucomatous. CONCLUSION: The optic discs at the atrophic stage of LHON eyes have glaucoma-like morphological changes. However, the cups were significantly deeper in NTG than LHON. The similarity in the optic disc findings in LHON and NTG suggests that alterations in mitochondrial function may be related to optic disc excavations.

Adolescent↗
PubMed2003

[A comparison of visual field and optic disc appearance depending on the peak intraocular pressure in patients with normal-tension glaucoma].

PURPOSE: To investigate the clinical differences between the two groups depending on the peak intraocular pressure(IOP) in patients with normal-tension glaucoma(NTG). METHODS: We studied 96 eyes of 48 NTG patients who were hospitalized for diurnal IOP measurement. Then we selected the eye whose peak IOP was higher than the other, or the right eye if the peak IOP of both eyes was equal. We divided these eyes into a "high-teen" group (peak IOP > or = 16 mmHg) and a "low-teen" group(peak IOP < or = 15 mmHg). We compared these two groups by age, gender, refraction, IOP, visual field defect, optic disc appearance, and tomograph. We used a Humphrey C 30-2 program to estimate the visual field defect and classified the optic disc into four types according to Nicolela's criteria. 22 eyes were imaged with Heidelberg Retina Tomograph (HRT) to obtain topographic parameters of the optic disc. RESULTS: There were no significant differences in age, gender, refraction, optic disc appearance, or tomograph between two groups. The trough and variation range of diurnal IOP were significantly larger in the high-teen group(p < 0.01). The value of mean deviation(MD) given by STATPAC was statistically lower in the high-teen group(p < 0.01). CONCLUSIONS: In patients with NTG, the visual field damage tended to be greater in the high-teen group than in the low-teen group. We surmise that the IOP might influence the progression of visual field defect in NTG.

Adult↗
PubMed2002

In situ confirmation of retinal blood flow improvement after carotid endarterectomy in a patient with ocular ischemic syndrome.

PURPOSE: To report a patient with ocular ischemic syndrome due to an internal carotid artery stenosis in whom we confirmed improved retinal blood flow noninvasively after carotid endarterectomy. DESIGN: Observational case report. METHODS: Retinal flowmetry. RESULTS: In a 72-year-old hypertensive man with a transient ischemic attack including dysgraphia, carotid angiography revealed approximately 90% stenosis of the left internal carotid artery. Standard carotid endarterectomy was performed. Postoperatively, good patency of the left internal carotid artery was confirmed by magnetic resonance angiography. We measured tissue blood flow in the fundus of each eye using a Heidelberg retina flowmeter before and after endarterectomy. Preoperative measurements showed reduction of blood flow in the left fundus, while values 3 months after surgery indicated a significant improvement of blood flow (P <.05, one-factor analysis of variance [ANOVA]). CONCLUSIONS: Retinal flowmetry can noninvasively detect differences in retinal blood flow between eyes in a patient with unilateral internal carotid artery stenosis and also assess the improvement of retinal blood flow after carotid endarterectomy.

Aged↗
PubMed2002

Neurofibromin and NF1 gene analysis in composite pheochromocytoma and tumors associated with von Recklinghausen's disease.

Composite tumor of pheochromocytoma and neuroblastoma, or ganglioneuroma, or ganglioneuroblastoma (composite pheochromocytoma), also known as mixed neuroendocrine and neural tumor, are sometimes combined with neurofibromatosis type 1 (NF1). To better understand the relationship between NF1 and composite pheochromocytoma, an immunohistochemical study using anti-neuro-fibromin that is an NF1 gene product and DNA sequence of NF1 Exon 31 were carried out in five cases of composite pheochromocytoma and in various tumors from five patients with NF1. Neurofibromin was not expressed in Schwann cells and sustentacular cells of composite pheochromocytomas and was very weakly or negatively expressed in neurofibroma of NF1 patients. However, it was strongly expressed in ganglionic cells and pheochromocytoma cells of the composite pheochromocytomas and also in mucosal ganglioneuromas, a gangliocytic paraganglioma, and in pheochromocytomas from the patients with NF1. Although there was no mutation in NF1 Exon 31, it could not be ruled out that there were mutations in other sites of the NF1 gene. Neurofibromin insufficiency may induce abnormal proliferation of Schwann cells in composite pheochromocytomas as well as in neurofibromatosis.

Adrenal Gland Neoplasms↗
PubMed2002

[Two families with primary open-angle glaucoma associated with myocilin gene mutations].

BACKGROUND: Myocilin is a gene that causes primary open-angle glaucoma(POAG). We found a family with normal tension glaucoma(NTG) whose members had an Asp 208 Glu mutation, and a family with POAG whose members had an Ile 360 Asn mutation in myocilin. CASE: In the family with the Asp 208 Glu mutation, the proband, a 31-year-old male, was diagnosed as having NTG. His mother had the same mutation and was also diagnosed as having NTG, but a sister with the same mutation showed no glaucomatous changes. We also found this mutation in normal controls. In the family with the Ile 360 Asn mutation, the proband, a 67-year-old female, was diagnosed as having POAG. Four members of this family showed different phenotypes including POAG, ocular hypertension, and normal. We found no cases with the same mutation in the controls. CONCLUSION: Since the Asp 208 Glu mutation was found in NTG, the pathogenesis of glaucoma with myocilin mutation might be more complex and it may be related to weakness of the optic nerve head. On the other hand, the mutation may be a polymorphism. The Ile 360 Asn mutation was considered to be disease-causing. However, both late-onset glaucoma cases and non-glaucomatous cases were observed in this family. The implications of the mutation and other risk factors remain to be discussed.

Adult↗
PubMed2002

[The correlation between retinal circulation and function in branch retinal artery occlusion].

PURPOSE: To investigate retinal circulation and function in eyes with branch retinal artery occlusion(BRAO) using a scanning laser Doppler flow-meter (SLDF) and multifocal electroretinogram (mERG). METHODS: In juxtapapillary and paramacular areas close to the occluded artery of the affected eye and the corresponding area of the fellow eye, the mean flow measured by SLDF, indicating microcirculation, and the p-wave amplitude in the response of mERG, indicating retinal function, were determined in three patients with BRAO at the period of reperfusion. The ratios of the affected eye to fellow eye(a/f ratio) were calculated, and the ratios of the mean flow (Fa/f) were compared with those of the p-wave amplitude(Pa/f). RESULTS: In the juxtapapillary area, both Fa/f and Pa/f decreased consistently, but in the paramacular area, Pa/f were lower than Fa/f in all cases. CONCLUSIONS: Functional recovery is likely to be later in the paramacular area than in the juxtapapillary area in the course of recovery of retinal circulation.

Adult↗