Biomedical subjects

D Z Wu

Publications and source records attributed to D Z Wu.

At least 19 recordsLinked to original sources

PubMed1992

The contrast sensitivity function in low vision.

The contrast sensitivity of 51 low vision patients (95 eyes) showed a substantial decrease in all spatial frequencies. The peak contrast sensitivity was shifted to 1 C/D from the normal 3-4 C/D. The high-frequency cut off is correlated to the visual acuity positively. Of the 33 patients, the preferred eye was the eye with better peak sensitivity in 28 patients (84%), while the preferred eye was the eye with better visual acuity in 22 patients (66%). It seems that the peak sensitivity is more important than visual acuity in determining eye preference. It provides a useful information for the clinician to determine which eye to train with low vision aids. Forty patients among 46 patients (87%) with RFN (Recognized Frequency Number) > or = 3 are able to read No.5 reading card, while 5 patients among 5 patients with RFN < 3 are not able to read No.5 reading card. The contributions of CSF to the low vision are evaluated.

Adolescent↗

PubMed1992

The electrophysiology in idiopathic senile macular hole.

Of 12 patients with idiopathic senile full-thickness macular hole, 3 had bilateral involvement, 9 had monocular macular hole. Flash ERG and pattern VEP were performed in the bilateral eyes of all patients. The abnormal rate of the pattern VEP was 93.3% when we used 15' checkboard stimulus, the changes of the VEP appeared as delayed latencies, reduced amplitudes or malformation of P100. The abnormal rate of the flash ERG was 53.3%, showing primary characteristics of reduced amplitudes of cone response b-wave. There was statistically significant difference between the abnormal rates of the VEP and the ERG (P < 0.05). The halo diameters of the macular hole were significantly related to the latencies of P100 (P < 0.01), but there was no correlation between the hole diameter and the latencies of P100. In 9 fellow eyes which did not form macular hole, 3 eyes had the abnormal pattern VEP, including one eye having formed macular cyst. The results show that, in idiopathic senile macular hole, the pattern VEP provides more functional information than does the ERG, and prompts the importance of close follow-up of fellow eye.

Aged↗

PubMed1992

Detection of gene alteration for color vision defects by polymerase chain reaction.

According to the fact that the abnormalities of visual pigment genes were always involved in the changing of the exon 5, two oligonucleotide primers were designed to amplify the exon 5 of red pigment gene and green pigment gene. After electrophoresis of the PCR products digested with Rsal or Sau3A, the DNA fragments from the exon 5 of red pigment gene (RPG) and green pigment gene (GPG) were separated since there are different restriction endonuclease sites. On the other hand, we analyzed the exon 5 related fragment by Southern blot hybridization with probe out of the 3' end of the fourth intron of green pigment gene. The results of PCR are consistent with nucleic acid hybridization. PCR technique will be of value in prenatal evaluation and genetic counselling.

Base Sequence↗

PubMed1992

Molecular basis of congenital color vision defects in Chinese patients.

Applying Southern blot hybridization, the structures of the red pigment gene (RPG) and the green pigment gene (GPG) were analyzed in 43 Chinese patients with red-green color vision defects, including 3 female cases of deuteranopia. The same analysis was carried out in 4 normal relatives and 3 carriers from 3 affected families, as well as in 11 normal controls. Among the 43 patients, abnormalities of the RPG were detected in all 19 protans, and abnormalities of the GPG were found in 14 of the 24 deutans. In about 80% of the protans and deutans, an alteration of exon 5 in RPG or GPG was discovered. All 19 protans had anomalous RPG and in one protan the normal RPG was replaced by a 5' red-3' green hybrid gene. However, no protans showed deletion of the whole RPG. Some deutans had no GPG; some had a 5' green-3' red hybrid gene with or without the GPG. The exon 5 of RPG and GPG was amplified by polymerase chain reaction (PCR) and the amplified fragments were further analyzed by RsaI digestion. The results of PCR were identical to those of nucleic acid hybridization. PCR will be a useful tool in prenatal diagnosis and genetic counseling.

Adolescent↗

PubMed1992

[Study on the toxicity and antitumor activity of adriamycin-DNA and amsacrine-DNA complexes in mice].

We have compared in vitro binding of adriamycin (ADR) and amsacrine (AMSA) with DNA, the toxicity, and the antitumor activity of ADR-DNA and AMSA-DNA, after intraperitoneal (ip) injection in mice. The binding of ADR with DNA is 100-fold higher than that of AMSA with DNA. The overall toxicity of ADR-DNA is significantly lower than that of ADR. ADR-DNA is more effective than ADR against three models of S180 sarcoma (by sc, ip and i.v. inoculation into mice). The peak levels of ADR-DNA and ADR were 265 +/- 24 ng.ml-1 versus 108 +/- 16 ng.ml-1 (P < 0.01). AUC 0-12 h were 1064 +/- 84 ng.h-1 x ml-1 versus 382 +/- 27 ng.h-1 x ml-1 (P < 0.01). The levels of ADR in most of tissues and tumor after administration of ADR-DNA were higher than those after administration of ADR. Moreover, there is no difference in toxicity, therapeutic effects as well as AUC between AMSA-DNA and AMSA.

Amsacrine↗

PubMed1992

Quantitative evaluation of flicker ERG waveforms in low vision patients.

Flicker electroretinograms (FERGs) of 30Hz were recorded for 46 eyes (23 cases) of low vision, including 38 eyes with retinal diseases and 8 eyes with optic neuropathy, and for 39 normal eyes (33 cases). The recorded wave forms were analysed by two methods: (1) to measure the peak to peak amplitude and pseudophase directly, and (2) to measure the amplitude and phase of fundamental response component (30Hz) by discrete Fourier transform (DFT). The abnormality ratios between these two methods were compared in low vision patients. All the eyes with optic neuropathy showed normal flicker ERG, the abnormality ratios of directly measured amplitude and the amplitude by DFT were 60.9% in 28 eyes and 71.7% in 33 eyes with retinal diseases respectively, the difference being no statistically significant (P > 0.05), while the abnormality ratios of directly measured pseudo-phase and the phase by DFT were 60.9% in 28 eyes and 82.6% in 38 eyes with retinal diseases respectively, the difference being statistically significant (P < 0.05). These results suggest that FERGs are an objective way to test the retinal function, and DFT for flicker ERGs are more useful in quantitative evaluation of the retinal function.

Adolescent↗

PubMed1992

The spectral VEP in normal subjects and dichromats.

The spectral VEP in 13 normal subjects (25 eyes), four cases (8 eyes) of protanopes and 8 cases (15 eyes) of deuteranopes were tested. In normal subjects, the shortest latencies of N1, P1, N2 were in 560 nm and the greatest amplitudes of N1-P1 and P1-N2 were 560-570 nm, around which the latencies were delayed and the amplitudes were decreased as the wavelengths of stimulative light increased or decreased gradually. The spectral VEP pattern of deuteranopes was similar to the normal subjects. In the protanopes, the shorter latencies of N1,P1,N2 and greater amplitudes of N1-P1, P1-N2 appeared in 520-530 nm and 570 nm, forming the two-thoughs and two-peaks shapes, with the shortest latencies and the greatest amplitudes in 520-530 nm. There were statistically significant differences of amplitudes and/or latencies in some wavelengths between the protanopes and normals and between the deuteranopes and normals.

Adolescent↗

PubMed1992

Visual functions and trace element metabolism in tobacco-toxic optic neuropathy.

Visual functions and nutrition metabolic characteristics were studied in 8 subjects (16 eyes) with tobacco-toxic optic neuropathy (TTON). Their visual functions tested by psychophysical and electrophysiologic methods showed that 1: 1. central vision diminished in 16 eyes, 2. dyschromatopsias were found in 14 tested eyes, 3. bilateral symmetrical central or cecocentral scotomas were the visual field characteristics in all cases, 4. PVEP were severe abnormal in 3 spatial frequencies in all cases and 56.3% of 15' checkboard PVEP showed flat responses, which indicated the impairment of optic nerve dominated by the central field. However, the preserved visual responses could be obtained by FVEP test in 14 tested eyes even though their visual acuity were between the range of 0.02-0.2 and flat PVEP responses. The II and III wave latencies of primary stage were more prolonged than those of control group (P < 0.01), which further indicated the preferential demyelination corresponding to the papillomacular bundles, 5. ERG showed slightly attenuated amplitudes in 5 of 8 tested eyes, which indicated the secondary and mild retinal lesion. On the other hand, TTON occurred on a background of long-term, heavy smoking, drinking, emaciation and malnutrition bodies with low serum zinc level.

Adult↗

PubMed1992

[A software design for standard grayscale printout of China-made automatic static quantitative TBC visual field analyser].

A method of "TBC GRAPH" software design for standard grayscale printout of TBC static quantitative perimetry is introduced. The software is operated in IBM PC/XT or PC/AT compatible computer, using Chinese Character Disk Operating System (CCDOS) which has widespread users in China. Symbols were established by using CCDOS word--make function, and sectoral as well as symbolic matrix were made, which realized the standard grayscale printout. The software is recommended for use in ophthalmic clinic and education.

Humans↗

PubMed1991

Visual rehabilitation in low vision patients with age-related macular degeneration.

Using optical visual aids, visual rehabilitation was performed in 14 low vision patients (25 eyes) with age-related macular degeneration. With distance aids, visual acuity improvement appeared in 24 eyes (95%) out of the 25 eyes. Twelve eyes (48%) obtained a visual acuity equal to or better than 0.4. With near visual aids, near acuity of all eyes (100%) was improved. Thirteen eyes (52%) got the near vision equal to or better than 0.5. Ten patients could read No. 5 Chinese Reading Card. The reading success rate was 71.4%. The results suggest that application of visual aids is an effective method to improve the distant and near visual acuity of low vision patients with AMD.

Aged↗

PubMed1991

The changes of fluorescein angiography and visual electrophysiology in ocular posterior aging degeneration syndrome (OPADS).

Ocular posterior aging degeneration syndrome (OPADS) is related to age excepting inflammation, trauma, tumor, congenital abnormalities. Clinically, it can be divided into several types: degeneration, pre-retinal membrane, hole and mixed types. Changes can be seen in the choroidoretina with fluorescein angiography. In the degeneration type, there are changes of chroid-blood vessels, pigment epithelium and neovasculization. The manifestation in pre-retinal membrane type are small vascular tortuosity, expansion or fluorescein leadage, retinal pigment epithelium window defects. The hole type shows lack of retinal capillaries and retinal pigment epithelium window defects. Visual electrophysiological tests by various intensities and colors show the abnormal ERG. The bio-electricity active changes indicated the correlation among several ocular posterior aging degeneration types.

Aged↗

PubMed1991

Spectral characteristics of electroretinogram in X-linked dichromats--a preliminary study.

Spectral characteristics of X-linked Dichromats (13 protanopes, 20 deuteranopes) were studied with spectral ERG. The results are as follows: The maximal spectral response of the b-wave in protanopes tended to shift toward the short wavelength side and the sensitivity to long wavelengths decreased obviously. The ratio value of the amplitude in 500 nm and in 620 nm (500/620) was greater in the protanope than that in the normal subject. Like the normals, the maximal response of the b-wave in deuteranopes appeared at 550-570 nm. Though the differences between the normals and deuteranopes in the ratio values (600/620 and b/a at 520 nm) were found by means of analysing a, b wave responses at each wavelength, most of the ratio values (600/620 or b/a at 520 nm) overlapped between the normals and deuteranopes. We established the discriminant function or score made up by the combination of two ratios basing on Fisher's rule, which can raise the diagnostic rate for deuteranopes.

Adolescent↗

PubMed1991

Abnormalities of ERG in congenital aniridia.

Congenital aniridia is generally associated with nystagmus, corneal pannus, cataract, ectopia lentis, glaucoma, macular hypoplasia, optic nerve hypoplasia and compromised visual function. Many theories have been proposed, including a failure in the development of the neural ectoderm and/or an aberrant development of mesoderm. We observed the ERG from 19 patients with congenital aniridia. Fourteen patients had abnormal ERG, including the reduced a wave trough under dark adapted red stimuli with dark adaptation; abnormal a or/and b waves in dark or/and light adapted ERG or abnormal oscillatory potentials. The ERG abnormalities reflected the disturbances either in the outer retina such as photoreceptors or in the structures of inner retina. The preserved visual function and several ocular abnormalities show that the aniridia may be a consequence of several pathogenetic mechanisms. This fact supported the opinion that congenital aniridia would be a concurrent failure of both ectoderm and mesoderm in embryonate development.

Adolescent↗

PubMed1991

The significance of testing preoperative visual function in cataract using laser interferometric visual acuity and ERG.

Tests of preoperative visual function and prediction of postoperative E chart visual acuity (ECVA) using laser interferometric visual acuity (LIVA) and electroretinogram (ERG) were performed in 16 cases (19 eyes) of cataract. The results showed that the coincident rate between preoperative LIVA and postoperative ECVA was 63.2%, and there was a parallel correlation between preoperative amplitude of photopic ERG b-wave and postoperative ECVA in 79.0% of the eyes. Comparing these two methods, the test of LIVA is very simple, fast, and is easily accepted by the patients with cataract. ERG is an objective method, which is slightly influenced by dense lens, but the test is more complex. Therefore, the combined use of these two methods will provide a more comprehensive and correct evaluation of preoperative visual function and a more reliable prediction for postoperative visual acuity in patients with cataract.

Adolescent↗

PubMed1991

Contrast sensitivity in amblyopia.

Contrast sensitivity function (CSF) for sinusoid gratings of varying spatial frequencies was determined for each eye of 21 cases with unilateral amblyopia. The CSF of all amblyopic eyes, except one, showed reduced sensitivity when compared with the non-amblyopic eye of the same person. The curve showed reduction more significantly at middle and high spatial frequencies. The cut-off frequency was shifted toward lower spatial frequencies. The relationship between CSF and various degree of amblyopia was also discussed.

Adolescent↗

PubMed1991

[Visual rehabilitation in low vision patients with aging macular degeneration].

Using optical visual aids, visual rehabilitation were performed in 14 cases (25 eye) of low vision patients with aging macular unity of all eyes (100%) was improved. Thirteen eyes (52%) got the near vision equal to or better than 0.5. Ten patients could read No. 5 Chinese Reading Card. The reading success rate was 71.4%. The results suggest that application of visual aids is an effective method to improve the distance and near visual acuity of low vision patients with AMD.

Age Factors↗

PubMed1991

[The color vision in patients with optic neuritis and chronic open-angle glaucoma].

Twenty eight cases (50 eyes) of chronic open-angle glaucoma and 21 cases (27 eyes) of optic neuritis were investigated with FM 100-hue test and panel D-15 test. In patients with optic neuritis, 70.37% and 85.19% of the affected eyes appeared abnormal in Panel D-15 test and FM 100-hue test respectively. The main defects were tritan-like in both of the tests. In patients with chronic open-angle glaucoma, 20% and 32% of the affected eyes had abnormal results in Panel D-15 test and FM 100-hue test respectively. The main defects were also tritan-like color vision defect. The total error scores of FM 100-hue test in patients with chronic open-angle glaucoma had no relation with the cup disc ratio and the area of peripheral visual field but had relation with the area of central visual field.

Adolescent↗

PubMed1991

[Clinical observation and analysis in age-related macular degeneration with one eye of wet form and the other of dry form].

Twenty two cases (44 eyes) of age-related macular degeneration with one eye of wet form and the other of dry form were included in this study. The range of the lesion was determined on magnified negative film of fluorescein angiography. In the dry group 72.7% eyes had normal FAZ and in the wet group 59.1% eyes revealed the lesion involving whole FAZ. The area of the lesion was measured by polar coordinates computational method, the mean area was 5.048mm2 in the wet form and 1.034mm2 in the dry form, there was statistically significant difference between the mean areas of the two groups (P < 0.01). The mean amplitude of photopic ERG b-wave was 101.74 mu v in the wet form and 126.35 mu v in the dry form. The morphological characteristics, the abnormalities of the visual function and possible changes in the two groups of this disease were discussed.

Age Factors↗