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Biomedical subjects

A Sawada

Publications and source records attributed to A Sawada.

162 records · Page 9Linked to original sources

Multifocal electroretinograms in normal subjects.

Multifocal electroretinography (ERG), developed by Sutter in 1992, is a method of recording the spatial distribution of focal ERG in a short time period using multi-input stimulation. Using this technique, we can detect the spatial extent and severity of damage to the macula. In this study, we recorded multifocal ERGs from 20 eyes of 20 normal subjects and analyzed the topographical properties of responses. In every subject, a negative wave followed by a positive wave could be recorded and we named them the N1-wave and the P1-wave, respectively. The amplitudes of the N1-wave and the P1-wave were the largest in the fovea, and they became smaller with eccentricity. In the P1-wave amplitude, the greatest intersubject variability was observed at the fovea. The N1 and P1 latencies were shorter in the upper retina than in the lower retina. The amplitude was larger in the upper retina than in the lower retina, which suggests the functional superiority of the upper retina. There was no statistical difference in latency and amplitude between the nasal and the temporal retina. We found no statistical difference between the responses of the papillomacular bundle and those of the temporal retinal area. The mapping obtained by multifocal ERG was useful as objective perimetry.

Adult↗

Effect of intraocular irrigating solution on flicker electroretinogram during cataract surgery in human eye.

The effects of two commercially available intraocular irrigating solutions, Opeguard MA and BSS Plus, were studied during extracapsular cataract surgery in 45 eyes of 35 patients. After irrigation and aspiration of the residual cortex with Opeguard MA or BSS-Plus, the ERG amplitude increased, respectively, to 111.2+/-5.8% and 109.5+/-5.3% of the preirrigation amplitudes. The increases reached significance (116.9+/-7.0% and 115.7+/-6.5%; both P < .05) at the end of surgery compared with pre-irrigation ERG amplitudes. After irrigation with Opeguard MA or BSS-Plus, the ERG peak times were significantly prolonged to 103.9+/-0.8% and 104.2+/-1.2%, respectively, of the preirrigation peak times (both P < .01). The ERG peak times significantly shortened to 101.5+/-0.9% and 101.3+/-1.22%, respectively, at the end of surgery (P < .001 and P < .05) compared with just after irrigation. Although we have previously shown that Opeguard MA maintained amplitude and implicit time of 30 Hz flicker ERG during vitrectomy better than BSS-Plus, there were no statistically significant differences between the changes in amplitude and peak time with Opeguard MA and BSS-Plus during cataract surgery. We speculate that a drop in the retinal temperature during irrigation and aspiration in the anterior chamber and an increase in the photopic ERG amplitude during light adaptation with the operating microscope caused these ERG changes.

Aged↗

Detection of a new TIGR gene mutation in a Japanese family with primary open angle glaucoma.

PURPOSE: To describe a new mutation of the trabecular meshwork-inducible glucocorticoid response protein (TIGR) gene in a Japanese patient with familial primary open angle glaucoma (POAG). METHODS: Standard ocular examinations were performed on the 44-year-old patient, his sister, and mother. DNA sequencing was used to identify the mutation. We also developed a DNA diagnostic method for detecting this missense mutation by polymerase chain reaction-induced mutation restriction analysis (PCR-IMRA). RESULTS: The patient, father, and sister had been diagnosed as having POAG. The patient and his sister had a Thr448Pro mutation (C-->A transition at the nucleotide number 1419) in exon 3. This mutation has not been reported before. CONCLUSIONS: Gene analysis is promising for an early diagnosis among the family members of familial POAG patients and will contribute to early therapy before an occurrence of irreversible visual impairment.

Aged↗

Prevalence of normal-tension glaucoma and primary open-angle glaucoma in patients with collagen diseases.

PURPOSE: To investigate the prevalence of normal-tension glaucoma (NTG) and primary open-angle glaucoma (POAG) in patients with collagen diseases and determine whether an immunocompromised condition is present in a subset of glaucoma patients. METHODS: Three glaucoma specialists prospectively examined patients with collagen diseases. The diagnostic process included applanation tonometry, slit-lamp examination, gonioscopy, direct ophthalmoscopy, and automated static perimetry. Twenty-four-hour intraocular pressure monitoring was done when necessary. Using the results of a population-based survey conducted in Japan, we calculated an expected number of cases of NTG and POAG, and compared these with the actual number of cases. RESULTS: Of the 153 patients with collagen diseases examined, we found 6 patients with NTG and 2 patients with POAG. Of these 8 patients, 2 with progressive systemic sclerosis (PSS), one with NTG, and the other, POAG, had a history of being on systemic steroidal therapy. The prevalence of NTG and POAG was significantly higher in women patients having collagen diseases as compared with normal women (P = .027). CONCLUSION: Women patients with collagen diseases are highly susceptible to NTG and POAG.

Adult↗

Effect of mitomycin C dissolved in reversible thermo-setting gel on the outcome of filtering surgery in the rabbit.

PURPOSE: Based on our previous report that showed enhanced transfer of mitomycin C to the sclera and the conjunctiva by dissolving the agent into a reversible thermo-setting gel, we conducted a study to investigate the efficacy of mitomycin C gel in the rabbit. METHODS: We subconjunctivally injected 0.1 mL of the mitomycin C gel solution containing several different amounts of the agent. Trephination was performed in the injected region 24 hours later. Intraocular pressure measurement, photography, and ultrasound biomicroscopic examination of the filtering bleb were conducted 1, 2, and 4 weeks postoperatively. RESULTS: The gel containing 3.0 microg or more mitomycin C significantly enhanced bleb formation and reduction in the intraocular pressure. CONCLUSIONS: The reversible thermo-setting gel seems to help the filtering bleb to survive in the rabbit and deserves further investigation as a new method of mitomycin C application.

Animals↗

Fast image accessing based on an analysis of the picture archiving and communications system in Kochi Medical School.

A large-scale picture archiving and communication system was developed by Kochi Medical School. Using JPEG to achieve 90% compression, this system was capable of storing several years worth of CT and MR examination records and eliminated the bottleneck in conventional systems caused by slow data access in the filing system. Under the new system, access of image files from client PCs was checked for bottlenecks. The image file retrieval from the image database on the server was found to require the longest time. Two methods were considered to eliminate this bottleneck. One was a multiimages filing into a file. Another was an image transmission with multiparallel transmission sessions, which is proposed in this article. By adopting the latter method, the system can transmit 50 CT images from the image database server to a client PC in about 10 s.

Humans↗

Cerebral hemiatrophy caused by multiple developmental venous anomalies involving nearly the entire cerebral hemisphere.

The authors present a case of multiple developmental venous anomalies (DVAs) that involved nearly the entire cerebral hemisphere and that were diagnosed by magnetic resonance (MR) imaging and selective cerebral angiography. The ipsilateral cerebral hemisphere was mildly atrophic, and there were focal white matter lesions on the MR images. Angiography showed multiple DVAs involving nearly the entire right cerebral hemisphere. We suggest that longstanding venous congestion caused the atrophy and white matter lesions.

Atrophy↗

Persistent primitive olfactory artery: diagnosis with MR angiography.

We present a case of persistent primitive olfactory artery (PPOA) diagnosed with the aid of magnetic resonance (MR) angiography. The proximal right anterior cerebral artery (ACA) had an extremely long anteroinferomedial course along the ipsilateral olfactory tract, made a hairpin turn posterosuperiorly, and became a normal distal ACA. After reviewing the literature, we considered the proximal segment of this anomalous ACA to be a PPOA. To our knowledge, this is the first report of a patient with this anomalous ACA diagnosed with MR angiography.

Adolescent↗

Supraclinoid carotid dissection in a pediatric patient.

The authors present the case of a 13-year-old boy with a left temporal lobe infarction that developed during a 400-m run. Magnetic resonance (MR) angiography showed segmental narrowing of the left supraclinoid internal carotid artery (ICA) and a duplicated left middle cerebral artery (MCA). MR angiographic source images revealed a crescent-shaped left carotid lumen, indicative of a supraclinoid carotid dissection.

Adolescent↗

Treatment of retinoblastoma with argon laser photocoagulation.

Treatment of retinoblastoma with argon laser photocoagulation in a five-month-old boy is described. His right eye had been enucleated for a large retinoblastoma. A small lesion in the left eye was successfully treated with argon laser. The patient has retained good vision without any complication and there has been no evidence of recurrence for four years.

Argon↗

Chronological observation in early radiation myelopathy of the cervical spinal cord: gadolinium-enhanced MRI findings in two cases.

Gd-enhanced MR images of two patients with clinically and histopathologically diagnosed chronic progressive radiation myelitis (CPRM) were observed chronologically. One of them had had nasopharyngeal cancer and received radiotherapy at a dose of 100 Gy to the C1-2 level of the spinal cord. She developed CPRM 25 months after the termination of radiotherapy. The other had had malignant lymphoma originating from the tonsil and received chemoradiotherapy. The dose delivered to her cervical spinal cord was 40 Gy, and she developed CPRM 30 months later. Gd-enhanced MRI in the early phase revealed a small crescent-shaped nidus with or without a very small central nonenhanced area in both cases. Enhancement was not great. At that time, patients noticed only the inability to perceive pain and temperature or paresthsia in the opposite side. In a few months, MRI revealed a much more strongly enhanced and larger nidus with enlargement of a central nonenhanced area accompanied by long segmental cord enlargement. The patients' neurological symptoms had also progressed, with hemiparesis developing, for example.

Adult↗