Objective:To study the trinucleotide repeats of GCN (GCA, GCT, GCC, GCG) encoding Alanine in exon 3 of the PHOX2B gene among healthy individuals from southwest China and two patients with Congenital central hypoventilation syndrome (CCHS). Methods:The number and sequence of the GCN repeats of the PHOX2B gene were analyzed by capillary electrophoresis, Sanger sequencing and cloning sequencing of 518 healthy individuals and two newborns with CCHS, respectively. Results:Among the 1036 alleles of the 518 healthy individuals, five alleles were identified, including (GCN) 7, (GCN) 13, (GCN) 14, (GCN) 15 and (GCN) 20. The frequency of the (GCN) 20 allele was the highest (94.79%). And five genotypes were identified, which included (GCN) 7/(GCN) 20, (GCN) 13/(GCN) 20, (GCN) 14/(GCN) 20, (GCN) 15/(GCN) 20, (GCN) 20/(GCN) 20. The homozygous genotypes were all (GCN) 20/(GCN) 20, and the carrier rate was 89.58%. Four GCN sequences of the (GCN) 20 homozygous genotypes were identified among the 464 healthy individuals. The GCN repeat numbers in the exon 3 of the PHOX2B gene showed no significant difference between the expected and observed values, and had fulfilled the, Hardy-Weinberg equilibrium. The genotypes of the two CCHS patients were (GCN) 20/(GCN) 25 and (GCN) 20/(GCN) 30, respectively. Conclusion:It is important to determine the GCN repeats and genotypic data of the exon 3 of the PHOX2B gene among the healthy individuals. The number of GCN repeats in 518 healthy individuals was all below 20. The selection of appropriate methods can accurately detect the polyalanine repeat mutations (PARMs) of the PHOX2B gene, which is conducive to the early diagnosis, intervention and treatment of CCHS.

Peripapillary intrachoroidal cavitation(PICC)is a common fundus lesion in high myopia.The typical mani-festation of PICC in fundus color photography is orange lesions with clear boundaries,which often occur below the myopic arc,and a weak reflection cavity in the choroid in optical coherence tomography(OCT).With the development and wide-spread application of OCT technology,researchers have gained a clearer understanding of the imaging features,pathogene-sis and clinical significance of PICC.This article introduces the definition,imaging features,pathogenesis,and relationship with glaucoma of PICC to provide new ideas for further elucidating the pathogenesis and clinical significance of PICC.

ObjectiveTo study the effect of Taikong Yangxin Pills on the metabolism of simulated weightless rats based on metabolomics and discuss the metabolism mechanism. MethodsIn the simulated space capsule environment on the ground， the rat model of simulated weightlessness was established by the tail suspension method. Rats were randomly grouped as follows： out-of-capsule control， in-capsule control， model， and high （3.0 g·kg^-1） and low （1.5 g·kg^-1） doses of Taikong Yangxin Pills， and they were administrated with corresponding drugs by gavage for 28 days. The serum levels of endogenous metabolites in rats were determined by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry （UPLC-Q-TOF/MS）. The obtained data were processed by principal component analysis （PCA） and orthogonal partial least squares-discriminant analysis （OPLS-DA） to screen for differential metabolites and potential biomarkers. MetaboAnalyst 5.0 was used for pathway enrichment analysis to explain the metabolic regulation mechanism of the drug. ResultsCompared with the out-of-capsule control group， the in-capsule control group showed elevated levels of thirteen metabolites， including 14-hydroxyhexadecanoic acid， linoleic acid， and α-linolenic acid （P<0.05）， which suggested that the space capsule environment mainly affected the metabolism of α-linolenic acid and linoleic acid in the rats. Compared with the in-capsule control group， the model group showed lowered levels of fourteen metabolites， including 4-imidazolone-5-propionic acid， isocitric acid/citric acid， and L-tyrosine （P<0.05）， which were recovered after the treatment with Taikong Yangxin pills （P<0.05）. The pathway enrichment analysis revealed that weightlessness induced by tail suspension and drug intervention mainly involved the phenylalanine， tyrosine， and tryptophan biosynthesis， tyrosine metabolism， histidine metabolism， and citric acid cycle. ConclusionThe simulated space capsule environment and simulated weightlessness induced by tail suspension can both affect the metabolism level of rats. Taikong Yangxin pills can ameliorate the metabolic abnormality in the rat model of weightlessness by regulating various amino acids and energy metabolism-related pathways.