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Biomedical subjects

Minzhong Yu

Publications and source records attributed to Minzhong Yu.

7 recordsLinked to original sources
PubMed2004

Multifocal electroretinographic evaluation of long-term hydroxychloroquine users.

OBJECTIVES: To observe the long-term effects of hydroxychloroquine sulfate on retinal electrical activity by multifocal electroretinography (mfERG) and to evaluate the regional variation of retinal dysfunction in subjects with hydroxychloroquine retinopathy. METHODS: Multifocal ERG with 103-hexagon stimulation was performed on 19 patients (36 eyes) treated with hydroxychloroquine for systemic lupus erythematosus, rheumatoid arthritis, or localized atypical scleroderma. Visual acuity testing, Amsler grid testing, and Ishihara color vision testing were also performed. In 2 of the patients, hydroxychloroquine was discontinued due to concerns about toxicity. Both of these patients had additional mfERG performed after discontinuation of medication. RESULTS: Twelve patients (19 eyes) had a normal response density in one or both eyes, including 6 patients (12 eyes) with a low lifetime dose (< or =438 g) of hydroxychloroquine who had normal response densities in both eyes. Eleven patients (17 eyes) had abnormal response densities in one or both eyes, and 2 of these patients (4 eyes) had significant attenuation of response densities in almost the whole tested field; 4 patients had a normal mfERG result for one eye but had a slight decrease of response densities for the other eye. There were 4 patterns of abnormal mfERG amplitude change observed: (1) paracentral loss, (2) foveal loss, (3) peripheral loss, and (4) generalized loss. Implicit times were abnormal for pericentral responses in 3 patients. The results of color vision and Amsler grid testing were normal, except for one patient with a generalized loss pattern. In 2 subjects in whom hydroxychloroquine toxicity was suspected, response densities improved after termination of hydroxychloroquine. CONCLUSIONS: Long-term hydroxychloroquine use may be associated with mfERG abnormalities. The mfERG appears to detect retinal physiological change earlier than visual acuity testing, color vision testing, or Amsler grid testing can. The greatest value of the mfERG is in differentiating a retinal cause and, hence, providing important evidence for hydroxychloroquine toxicity, for whatever visual field loss is apparent on perimetry.

Adult↗
PubMed2003

The multifocal electroretinogram in X-linked juvenile retinoschisis.

To measure and compare the multifocal electroretinography in normal control and X-linked juvenile retinoschisis, 13 cases (13 right eyes) of normal control and nine cases (17 eyes) of X-linked juvenile retinoschisis were measured with VERIS Science 4.0. Four cases (eight eyes) out of the nine retinoschisis cases were tested with Ganzfeld ERG at the same day. The results showed statistically significant difference of average response densities and latencies in six ring retinal regions between the normal control and retinoschisis. The trace array and 3-D topography of multifocal ERG showed multi-area amplitude decrease with absence or reduction of central peak amplitude in patients with retinoschisis. The P1/N1 ratio of multifocal ERG average response densities in six ring retinal regions was different from the b/a ratio of Ganzfeld ERG. The multifocal ERG and Ganzfeld ERG each had its advantage in the diagnosis of retinoschisis.

Adult↗
PubMed2002

Effect of indocyanine green angiography using infrared fundus camera on subsequent dark adaptation and electroretinogram.

To observe the effect of indocyanine green angiography (ICGA) with infrared fundus camera on subsequent dark adaptation and the Ganzfeld electroretinogram (ERG), the ERGs of 38 eyes with different retinal diseases were recorded before and after ICGA during a 40-min dark adaptation period. ICGA was performed with Topcon 50IA retina camera. Ganzfeld ERG was recorded with Neuropack II evoked response recorder. The results showed that ICGA did not affect the latencies and the amplitudes in ERG of rod response, cone response and mixed maximum response (p>0.05). It suggests that ICGA using infrared fundus camera could be performed prior to the recording of the Ganzfeld ERG.

Adolescent↗
PubMed2002

[Change in visual evoked potential by radiotherapy of nasopharyngeal carcinoma].

OBJECTIVE: To study the effect of radiotherapy of nasopharyngeal carcinoma on visual evoked potential (VEP). METHODS: VEP of 63 patients with nasopharyngeal carcinoma were tested before, at the end of, half a year, one year, 2 years and 3 years after their radiotherapy. RESULTS: Within the male group, one year after radiotherapy, the latency of VEP was significantly delayed than that before and at the end of radiotherapy, while the amplitude was decreased significantly. Two years after radiotherapy, the latency of VEP was significantly delayed more than that before radiotherapy. However there was no significant difference among VEP at the end of, half a year and 3 years after radiotherapy. Within the female group, 2 years after radiotherapy, the latency of VEP was significantly delayed than that before radiotherapy. Three years after radiotherapy, the latency of VEP was significantly delayed than that before, at the end of, half a year and one year after radiotherapy. There was no significant difference in VEP amplitudes before and after radiotherapy. CONCLUSION: Within the male group, the abnormal delay of VEP latency mostly happens one or two years after radiotherapy. Within the female group, the significant delay of VEP latency happens at the end of radiotherapy and lasts for 3 years, while the VEP amplitude does not change significantly during the 3 years after radiotherapy. The result indicates that the sustained radiation damage within the female visual nerve system starts at the end of radiotherapy, but to a lesser degree. It was shown that radiotherapy of nasopharyngeal carcinoma certainly damages the visual nerve system, though there is sex difference in the impairment.

Adult↗
PubMed2002

Multifocal electroretinograms in the early stages of diabetic retinopathy.

OBJECTIVE: To investigate the characteristics of multifocal electroretinograms (mf-ERG) of different phases in diabetic retinopathy (DR) and its clinical significance. METHODS: Multifocal electroretinograms in patients with DR (I - II stage) were tested with VERIS IV system. RESULTS: In I - II stage, the absolute values of N1, P1 and N2 response densities, and the N1-P1 and P1-N2 response densities were attenuated is a field of about 45 degrees in diameter. CONCLUSION: As a new objective and quantitative examination for spatial visual function, multifocal electroretinograms may be valuable in the diagnosis of diabetic retinopathy.

Aged↗