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Y L Zou

Publications and source records attributed to Y L Zou.

5 recordsLinked to original sources
PubMed1999

Evaluation of methods for assessing visual function of infants.

PURPOSE: Commonly used behavioral and electrical testing methods for estimation of visual acuity and visual function in infants yield different estimates and may not accurately predict visual acuity and visual function in later life. Moreover, neither test-retest variability nor side-by-side comparisons of the various methods have been thoroughly evaluated in the same infant population. The purpose of this study was to provide such an evaluation. METHOD: The test-retest variability of visual acuity and visual function was evaluated for the Teller Acuity Card (TAC) procedure, sweep visual evoked potential (VEP), as well as latency and amplitude measured by transient pattern VEP. Groups of approximately 20 infants contributed test-retest data. Visual function estimated by the various methods in a larger group of infants (n = 118) was compared. Correlations between methods and the validity of the various methods to detect maturational changes between 4 and 8 months of age were also assessed. Administration of these tests was according to standard and usual procedures. RESULTS: The average percent difference between test and retest estimates of acuity as well as the SD was lowest for transient VEP latency (3%, 7% SD). The other methods were markedly more variable: sweep VEP (2%, 22% SD), TAC procedure (8%, 20% SD), and transient VEP amplitude (7.5%, 39% SD). Average coefficients of variation showed a similar trend: transient VEP latency, 8%; sweep VEP, 15%; TACs, 30%; and transient amplitude, 53%. Correlations among estimates by the methods were poor, but expected changes in visual maturation from 4 to 8 months of age were detected with all methods. CONCLUSIONS: All methods evaluated provide valid and reliable test-retest data for a group, but are less valid for estimating visual acuity and visual function of an individual subject. The poor correlations between any 2 of the testing methods suggest that each test assesses a different aspect of vision. Nonetheless, expected maturational changes between 4 and 8 months of age were readily detectable by all methods evaluated.

Aging↗
PubMed1995

Comparative cutaneous testing with purified protein derivative and the antigen complex A60 in vaccinated subjects and tuberculosis patients.

Some 840 bacille Calmette-Guérin (BCG)-vaccinated healthy controls and tuberculosis patients from two Chinese hospitals were submitted to comparative skin tests with purified protein derivative of tuberculin (PPD; as reference) and with the antigen complex A60 from Mycobacterium bovis BCG. In a first trial, including 581 persons (185 healthy juveniles, 180 healthy adults and 216 tuberculosis patients), a limited dose of A60 (1 microgram) was used. Performance of the A60 test was similar to that of 5 I.U. PPD for controls (cut-off values = 5 mm induration diameter), but lower than that seen for tuberculosis patients (10 mm cut-off values). A second survey was conducted on 259 persons (109 recently revaccinated healthy persons, considered as tuberculin-negative in the first trial, and 150 tuberculosis patients), using a higher dose of A60 (2 micrograms) and the same dose of PPD (5 I.U.). Similar results were obtained with the two tests in all cases, thus supporting the possibility of PPD replacement by A60 in cutaneous testing. The pattern of induration diameter distribution in healthy subjects who took part in the first testing round (64% positively rate) was displaced to the inactivity side (with a peak at 5 to 9-mm diameter), in comparison with the second round (90% positivity rate and peak at 10-14 mm). This indicates a progressive fading of cellular immunity reactions after BCG vaccination. In tuberculosis patients, no correlation was found among the following three parameters: positivity at cutaneous testing (with PPD or A60), titer of anti-A60 mycobacterial immunoglobulins in blood (IgG titer higher than cut-off line) and presence of mycobacteria in sputum.

Adolescent↗
PubMed1994

Serological analysis of pulmonary and extrapulmonary tuberculosis with enzyme-linked immunosorbent assays for anti-A60 immunoglobulins.

IgA, IgG, and IgM antibodies to mycobacterial antigen A60 were measured by ELISA in blood, pleural fluid, and cerebrospinal fluid from 560 patients with pulmonary and/or extrapulmonary tuberculosis who were being treated at hospitals in northern China and from 734 uninfected controls. Among 529 healthy persons (most of whom had been vaccinated with bacille Calmette-Guérin [BCG] and 287 of whom were tuberculin-positive), the rate of false-positive results was negligible; this observation ruled out interference of remote BCG vaccination with A60 assays at the chosen cutoff level. Rates of positivity for IgM and IgG, respectively, were 80% and 36% among patients with active primary pulmonary tuberculosis, 31% and 88.5% among patients with active postprimary pulmonary tuberculosis, 0 and 41% among patients with inactive pulmonary tuberculosis, and 30%-61% and 69%-86% among patients with extrapulmonary tuberculosis. Paired samples of blood and pleural fluid from patients with pleurisy contained IgA antibody to A60 at equal titers; in contrast, most patients with tuberculous meningitis (100% of whom had a positive ELISA result) had higher levels of IgG antibody to A60 in cerebrospinal fluid than in blood--proof of intrathecal synthesis.

Adult↗
PubMed1994

Analysis of tuberculous meningitis cases by an immunoblotting assay based on a mycobacterial antigen complex.

Tuberculous meningitis cases were analyzed by an immunoblotting test based on Mycobacterium bovis BCG antigen complex A60. Anti-A60 immunoglobulin G (IgG) in cerebrospinal fluid (CSF) allowed early diagnosis, and concentrations decreased after recovery. In primary meningitis forms, anti-A60 IgGs were intrathecally synthesized and specific oligoclonal IgGs were present in CSF. In meningeal complications of pulmonary tuberculosis, there were matching titers of anti-A60 IgG in blood and CSF (mirror pattern). Correlation between CSF-restricted patterns and CSF pleocytosis was shown.

Adolescent↗