Objective To determine the amount of serum Vitamin D in premature infants,and to investigate its correlation with bone quantitative ultrasound measurement.Methods The serum of premature infants born between 2013 March and 2014 March in the Maternal and Children Health Hospital of Huadu District in Guangzhou were collected,and serum 25-hydroxyvitamin D [25-(OH) D] level was measured by using chemiluminescence immunoassay,while Omnisense quantitative ultrasound was used to measure bone speed of sound(SOS) in the middle area of the left tibia.According to gestational age,the participants were divided into A,B and C groups(28-32 weeks,32 +1-34 weeks,34 + 1-36 +6 weeks,respectively).The levels of 25-(OH)D and SOS were compared and the correlation between them was analyzed.Results The amount of 25-(OH) D of the 3 groups was (41.65 ± 21.15) nmoL/L,(47.15 ± 19.78) nmol/L,and (49.35 ± 19.93) nmol/L,respectively,and the differences among the 3 groups were statistically significant (F =4.441,P =0.012).The ratio of vitamin D abundant or not (insufficiency including deficiency and lack) in preterm among the 3 groups were compared,and the differences among the 3 groups were statistically significant(x2 =11.38,P =0.023).SOS of the 3 groups were (2 787.85 ± 123.01) m/s,(2 865.12 ± 129.44) m/s and (2 908.59 ± 124.01) m/s,respectively,and the differences among the 3 groups were statistically significant (F =28.716,P =0.000).There was a positive correlation between 25-(OH) D and SOS (r =0.084,P =0.024).Conclusions Level of Vitamin D in premature infants is generally inadequate.The smaller the gestational age,the higher the occurrence rate.Vitamin D levels and SOS are significantly positively correlated,and both of them increase with gestational age.

Objective To explore the mechanism of combined treatment with methotrexate (MTX) and Ga-Al-As laser irradiation for rheumatoid arthritis (RA) and to assess the effectiveness of Ga-Al-As laser therapy for RA. Methods Twenty-two patients with RA were randomly and evenly divided into two groups: the treatment group treated with Ga-Al-As laser irradiation combined with MTX and the control group treated with MTX only. Ten age-matched normal subjects were observed as normal controls. The amount of CD4 + CD25 + regulatory T cells in peripheral blood (PB) of the normal controls and that in the PB and synovial fluid (SF) of the 22 patients before and after therapy were counted by flow cytometry. Meanwhile, the amount of prostaglandin E2 (PGE2) in synovial fluid of the patients was measured before and after treatment by enzyme-linked immunosorbent assay(ELISA). Results After combined treatment the clinical symptoms of the patients were improved significantly, and the amount of PGE2in SF decreased significantly. The count of CD4 + CD25 + regulatory T cells in PB of RA patients was ( 3.84 ±3.20) % , compared to ( 10.05 ± 7.04) % in healthy individuals. The count of CD4 + CD25 + regulatory T cells in SF of RA patients was ( 14.89 ± 12.30) % , much higher than that in PB. The count of CD4 + CD25 + regulatory T cells in SF decreased significantly in treatment group compared to control group (P ＜0.05). Conclusion Ga-Al-As laser irradiation eombined with MTX can effectively improve the clinical symptoms of RA patients. It may be related to the decrease of amount of PGE2 and count of CD4 + CD25 + regulatory T cell in PB and SF.