Hong Jae Chae

Gonadotropin-releasing hormone stimulation test for precocious puberty.

Background Gonadotropin-releasing hormone (GnRH) stimulation test is the gold standard to identify central precocious puberty (CPP). This test requires multiple blood samples at different time points to measure gonadotropin levels, and is therefore expensive, time-consuming, and uncomfortable for patients. We aimed to simplify the GnRH stimulation test to require fewer blood samples. Methods A study of 166 girls with precocious puberty was undertaken. Blood samples were obtained at 0, 15, 30, 45, 60, 90, and 120 min after GnRH administration, and the levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were measured. For each parameter, the sensitivities and specificities were estimated and ROC curves were constructed. Results One hundred and twenty-eight patients (77.1%) were diagnosed for CPP. Peak LH levels were achieved 30 min after GnRH stimulation in patients with CPP. Further, 98.4% of the 45-min samples were diagnostic for CPP, and the cumulative frequency of LH values of ≥5 IU/L was 100% at 45 min. Using this cut-off value for LH, the ROC curve for LH at 45 min showed the highest sensitivity (98.4%) and specificity (100%) in the diagnosis of CPP. Conclusions Values of LH measured from a single blood sample obtained at 45 min in the GnRH stimulation test may be adequate for the diagnosis of CPP. Two samples, taken at 30 and 45 min after stimulation, were able to accurately diagnose CPP in 100% of the patients in this study.

Color vision impairments among shipyard workers exposed to mixed organic solvents, especially xylene

OBJECTIVES We evaluated color vision impairment in workers exposed to organic solvents, especially xylene. METHODS Three groups of subjects, comprising 63 workers occupationally exposed to organic solvents, 122 non-exposed workers in the same industry, and 185 subjects from the general population as controls, were evaluated for color vision. Exposure to solvents was indirectly evaluated by measuring the concentration of a urinary metabolite. Color vision was assessed using the Lanthony Desaturated 15-hue (Lanthony D-15) panel. RESULTS Color confusion index (CCI) values in the exposed group were significantly higher than in the non-exposed workers or the general population, after adjustment for age and education, and significantly correlated with the concentration of methylhippuric acid. Color vision impairments were detected more frequently among the exposed group, and the most common types were type III and complex impairments. The rate of type III impairments was 9.52% in the exposed group, 1.64% in the non-exposed group, and 1.62% in the general population. CONCLUSION Our results support the hypothesis that acquired color vision impairments could be induced by exposure to xylene. Testing for color vision impairment is a relatively simple, non-invasive and sensitive diagnostic method for relatively low-level exposures to xylene.

Usefulness of color vision test for early detection of neurological damages by neurotoxic substances

This paper reviews the published literature that is concerned with color vision impairment from industrial and environmental exposure to neurotoxic substances, and we evaluated whether testing for color vision impairment could be an affordable procedure for assessing these neurotoxic effects. In general, most cases of congenital color vision impairment are red-green, and blue-yellow impairment is extremely rare. However, most of the acquired color vision impairment that is related to age, alcohol or environmental factors is blue-yellow impairment. Therefore, many studies have been performed to identify this relationship between exposure to neurotoxic substances, such as organic solvents and heavy metals, and the prevalence of blue-yellow color vision impairment. The test for color vision impairment is known to be very sensitive to the early signs of nervous system dysfunction and this can be useful for making the early diagnosis of neurotoxic effects from exposure to very low concentrations of toxic substances.