[Biochemical screening and genetic diagnosis of thalassemia in children from Kunming].

OBJECTIVE: To investigate the types and frequency of gene mutations in children with thalassemia in Kunming, Yunan Province. METHODS: A biochemical screening for thalassemia was performed by testing RBC fragility, MCV and hemoglobin electrophoresis on 1338 children from Kunming, Yunnan Province. Genetic diagnosis was performed on the children with α-thalassemia by gap-PCR and on the children with ß-thalassemia by PCR-RDB. RESULTS: The positive rate of the biochemical screening for thalassemia was 11.36% (152 cases). The positive rate of genetic diagnosis was 8.59% (115 cases). Of the 115 cases, α-thalassemia was found in 43 cases, ß-thalassemia in 68 cases and α-combined-ß thalassemia in 4 cases.--SEA/αα accounted for 47%, -α4.2/αα accounted for 21%, and HbH disease accounted for 14%. Six genotypes were found in 68 cases of ß-thalassemia and the mutation frequency of ßE was the highest (32%), followed by CD41-42 (24%), CD17 (23%), IVS-II654 (10%), CD71-72 (10%), and -28 (1%). CONCLUSIONS: The frequency of gene mutations for thalassemia is high in children from Kunming, Yunnan Province. Premarital and prenatal screenings and genetic diagnosis for thalassemia should be carried out in this area.

Expression of pax-6 in rhesus monkey of optical defocus induced myopia and form deprivation myopia.

BACKGROUND: Pax-6 gene plays an important role in the process of eye development. This study was to determine the role of pax-6 in the axial myopia produced by hyperopic optical defocus and form deprivation in infant monkeys. METHODS: Among seven normal infant rhesus monkeys (aged 1 to 1.5 months), five wore -3.00 D spectacle lenses over their right eyes and zero-powered lenses over their left eyes. Monocular form deprivation was produced by eyelid fusion in two monkeys. Ten weeks later, the monkeys were sacrificed by an overdose of barbiturates and their eyes were removed immediately. A 5 mm x 5 mm button of retina and sclera was taken from the posterior poles along with a 4-mm optic nerve. RNA was isolated separately from each of these three types of tissues. After that, reverse transcription polymerase chain reaction (RT-PCR) was used for determining gene expression in the retina, sclera and optic nerve. Semi-quantitative analyses were performed on the PCR products. RESULTS: As expected, the optically induced hyperopic defocus and the form deprivation produced myopic growth. For the lens-treatment monkeys, pax-6 gene expression in the retinas of the defocused eyes was significantly higher than in the retinas of the left eyes (t = 5.703, P = 0.005). However, there were no analogous significant differences between pax-6 expression in the scleras or the optic nerves. For the two form-deprived monkeys, there were no obvious differences in pax-6 gene expression in the retinas or the optic nerves. CONCLUSION: The result that the expression of pax-6 was enhanced by hyperopic defocus in the infant monkey retina suggests that pax-6 may be involved in vision-dependent eye growth and emmetropization.

Development and clinical trial of fluorescence PCR diagnostic kit to detect Mycobacterium tuberculosis.

OBJECTIVE: To develop a new diagnostic kit for Mycobacterium tuberculosis (TB) detection on the basis of fluorescence PCR (F-PCR) and conduct clinical trial of this kit for assessing its performance in comparison with other diagnostic methods. METHODS: We collected 546 clinical sputum samples from patients with phthisis and normal subjects to examine TB by way of F-PCR in parallel with examination with modified R.culture, auramine smear with fluorescence staining and LCx DNA diagnostic kit from Abbott for comparison. RESULTS: A clinical diagnostic kit for TB detection was developed with F-PCR, and clinical trial showed that its positivity rate was 49.1%, sensitivity 89.2%, specificity 98.8% and efficiency 93.6%. CONCLUSION: F-PCR is obviously superior to culture method and smear method and comparable with LCx in terms of sensitivity, and can be used to monitor TB DNA in the secretions to facilitate clinical diagnose and therapeutic effects monitoring.