Zinc metabolism was determined with 88Zn and 70Zn, stable isotopes of zinc, in two volunteers who went through different levels of zinc nutriture for 15 weeks. It was shown that zinc metabolic pool size could correctly reflect zinc nutriture. The difference between fasting and postprandial plasma zinc concentration was more reliable than fasting plasma zinc concentration alone. The sense of daily urinary and fecal zinc excretion were rather limi ted. In a certain sense, fecal endogenous zinc excretion was valuable for establishing recommendation dietary allowance of zinc.

Objective: To observe the effects of dietary zinc deficiency on the apoptosis of immunocytes in 3 weeks old rats and study the underlying mechanism. Methods: A zinc-deficient growing rat model was developed. Using TUNEL(terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling) method, the apoptosis of thymocytes and spleen lymphocytes was checked. The expression of bcl-2, bax mRNA in thymus and spleen was detected by RT-PCR. Results: Compared with zinc adequate(ZA) and paired-fed(PF) groups, the percentage of apoptosis cells in thymus and spleen of zinc-deficient(ZD) rats was obviously higher, and the thymus and spleen of ZD rats had a higher expression of bax mRNA. Zinc supplementation could reverse these changes. Conclusion: Dietary zinc deficiency leads to the increase of apoptosis of lymphocytes in thymus and spleen. One important mechanism is that the thymus and spleen have higher expression of bax mRNA, which causes the decrease of bcl-2/bax ratio.

Objective: To observe the effects of zinc deficiency on peripheral blood lymphocyte phenotypic distribution and the balance between Th1 and Th2 cells in growing rats. Methods: Two-color cytofluorometric analysis was used. Results: Compared with zinc adequate (ZA) and paired-fed (PF) groups, peripheral blood lymphocytes in zinc deficient (ZD) rats had higher percentage of CD8+ cells (cytolytic T cells), lower percentage of CD4+ cells (T helper cells) and lower percentage of CD45RA+ cells (pure B lymphocytes).In addition, zinc deficiency selectively caused reduction of Th1-like CD45RC+CD4+ cells , but Th2-like CD45RC-CD4+cells had no significant changes in weanling rats. Zinc supplementation could reverse these changes. Conclusion: Dietary zinc deficiency leads to changes of lymphocyte phenotypic distribution and the imbalance of Th1 and Th2 subsets. These changes are reversible.

Objective To analyze the imaging characteristics of thoracic LDRD(Low-dose directly Digital Radiographic Device) and its artifacts.Methods 188 patients were performed with LDRD and common thoracic X-ray film respectively in our hospital during two weeks.Results Among the 188 cases,1.60%(3/188) showed thoracic motion artifacts.46.8%(88/188) appeared as tentorial prominence along left heart edge and 2.6%(5/188) along the right one.1 artifact was in aorta-pulmonary artery window(0.53%).Conclusion(1)Less than 0.5 should be taken as reference in podoid enlargement diagnosis.(2)Pseudomorph from heart motion may result from cardio-phase,cardiac contraction,heart rate,arrhythmia,local abnormal pulse of left heart edge,different enlarged velocity of cardiac cavity during heart beat,etc.(3)The motion artifacts in thoracic LDRD has no important influence in clinical diagnosis and therapy.

Objective To investigate the risk factors of hyperbilirubinemia in late preterm infants. Methods The clinical data of 815 late preterm infants (449 males and 366 females) from 25 hospitals in Beijing were collected from October 2015 to April 2016, including 340 cases(41.7％) with hyperbilirubinemia (hyperbilirubinemia group), and 475 cases without hyperbilirubinemia (control group). The clinical data of two groups were compared, and the maternal factors influencing hyperbilirubinemia in late preterm infants were analyzed with logistic regression. Results There were no significant differences in gender ratio (M:F 1.39 vs. 1.12, t=1.811,P=0.172)and birth weight[(2502.6±439.6)g vs. (2470.2±402.9)g,χ2=2.330,P=0.127)]between two groups. The incidence rates of hyperbilirubinemia in infants of 34 wks, 35 wks and 36 wks of gestational age were 22.9％(87/174), 35％(119/300) and 42.1％(143/341) respectively (χ2=1.218,P=0.544). The multivariate logistic regression analysis indicated that the maternal age(OR=1.044,95％ CI:1.010-1.080,P=0.011)was independent risk factor and multiple births(OR=1.365,95％CI:0.989-1.883,P=0.048), premature rupture of membranes(OR=2.350,95％ CI:1.440-3.833,P=0.001), cesarean section(OR=1.540,95％CI:0.588-4.031,P=0.014)were risk factors for hyperbilirubinemia in late preterm infants. Conclusions The incidence of hyperbilirubinemia in late preterm infants is relatively high. Maternal age, multiple births, premature rupture of membranes and cesarean section are risk maternal factors related to hyperbilirubinemia in late preterm infants.

Objective:In general, patients with seropositive rheumatoid arthritis (RA) are considered to show an aggressive disease course. However, the relationship between the two subgroups in disease severity is controversial. Our study is aimed to compare the clinical characteristics and prognosis of double-seropositive and seronegative RA in China through a real-world large scale study.Methods:RA patients who met the 1987 American College of Rheumatology (ACR) classification criteria or the 2010 ACR/European Anti-Rheumatism Alliance RA classification criteria, and who attended the 10 hospitals across the country from September 2015 to January 2020, were enrolled. According to the serological status, patients were divided into 4 subgroups [rheumatoid factor (RF)(-) anti-cyclic citrullinated peptide (CCP) antibody (-), RF(+), RF(+) anti-CCP antibody(+), anti-CCP antibody(+)] and compared the disease characteristics and treatment response. One-way analysis of variance was used for measurement data that conformed to normal distribution, Kruskal-Wallis H test was used for measurement data that did not conform to normal distribution; paired t test was used for comparison before and after treatment within the group if the data was normally distributed else paired rank sum test was used; χ2 test was used for count data. Results:① A total of 2 461 patients were included, including 1 813 RF(+) anti-CCP antibody(+) patients (73.67%), 129 RF(+) patients (5.24%), 245 RF(-) anti-CCP antibody(-) patients (9.96%), 74 anti-CCP antibody(+) patients (11.13%). ② Regardless of the CCP status, RF(+) patients had an early age of onset [RF(-) anti-CCP antibody(-) (51±14) years old, anti-CCP antibody(+) (50±15) years old, RF(+) anti-CCP antibody(+) (48±14) years old, RF(+)(48±13) years old, F=3.003, P=0.029], longer disease duration [RF(-) anti-CCP antibody(-) 50 (20, 126) months, anti-CCP antibody(+) 60(24, 150) months, RF(+) anti-CCP antibody(+) 89(35, 179) months, RF(+) 83(25, 160) months, H=22.001, P<0.01], more joint swelling counts (SJC) [RF(-) anti-CCP antibody(-) 2(0, 6), Anti-CCP antibody(+) 2(0, 5), RF(+) anti-CCP antibody(+) 2(0, 7), RF(+) 2(0, 6), H=8.939, P=0.03] and tender joint counts (TJC) [RF(-) anti-CCP antibody(-) 3(0, 8), anti-CCP antibody(+) 2(0, 6), RF(+) anti-CCP antibody(+) 3(1, 9), RF(+) 2(0, 8), H=11.341, P=0.01] and the morning stiff time was longer [RF(-) anti-CCP antibody(-) 30(0, 60) min, anti-CCP antibody(+) 20(0, 60) min, RF(+) anti-CCP antibody(+) 30(10, 60) min, RF(+) 30(10, 60) min, H=13.32, P<0.01]; ESR [RF(-) anti-CCP antibody(-) 17(9, 38) mm/1 h, anti-CCP antibody(+) 20(10, 35) mm/1 h, RF(+) anti-CCP antibody(+) 26(14, 45) mm/1 h, RF(+) 28(14, 50) mm/1 h, H=37.084, P<0.01] and CRP [RF(-) anti-CCP antibody(-) 2.3 (0.8, 15.9) mm/L, Anti-CCP antibody(+) 2.7(0.7, 12.1) mm/L, RF(+) anti-CCP antibody(+) 5.2(1.3, 17.2) mm/L, RF (+) 5.2(0.9, 16.2) mm/L, H=22.141, P<0.01] of the RF(+)patients were significantly higher than RF(-) patients, and RF(+) patients had higher disease severity(DAS28-ESR) [RF(-) anti-CCP antibody(-) (4.0±1.8), anti-CCP antibody(+) (3.8±1.6), RF(+) anti-CCP antibody(+) (4.3±1.8), RF(+) (4.1±1.7), F=7.269, P<0.01]. ③ The RF(+) anti-CCP antibody(+) patients were divided into 4 subgroups, and it was found that RF-H anti-CCP antibody-L patients had higher disease severity [RF-H anti-CCP antibody-H 4.3(2.9, 5.6), RF-L anti-CCP antibody-L 4.5(3.0, 5.7), RF-H anti-CCP antibody-L 4.9(3.1, 6.2), RF-L anti-CCP antibody-H 2.8(1.8, 3.9), H=20.374, P<0.01]. ④ After 3-month follow up, the clinical characteristics of the four groups were improved, but there was no significant difference in the improvement of the four groups, indicating that the RF and anti-CCP antibody status did not affect the remission within 3 months. Conclusion:Among RA patients, the disease activity of RA patients is closely related to RF and the RF(+) patients have more severe disease than RF(-) patients. Patients with higher RF titer also have more severe disease than that of patients with low RF titer. After 3 months of medication treatment, the antibody status does not affect the disease remission rate.

Objective:To study the respiratory morbidity and the risk factors of respiratory complications in late-preterm infants.Methods:The data of 959 late-preterm infants in 21 hospitals in Beijing from October 2015 to April 2016 were collected.These infants were divided into the respiratory morbidity group (237 cases) and the control group (722 cases) according to whether they had short-term respiratory morbidity after birth.Clinical data of the two groups were compared.Results:Among the 959 late-preterm babies, 530 were male and 429 were female.Two hundred and thirty-seven cases (24.7%) developed short-term respiratory morbidity after birth.Infectious pneumonia developed in the most cases (81 cases, 8.4%), followed by transient tachypnea (65 cases, 6.8%), amniotic fluid aspiration (51 cases, 5.3%), and respiratory distress syndrome (24 cases, 2.5%) successively.All the infants recovered and discharged.There were no differences between gender and maternal age between 2 groups (all P>0.05). Compared with the control group, more late-preterm infants were delivered by cesarean section (73.4% vs.59.7%, χ2=14.43, P<0.001) and the 1-minute Apgar score was lower [(9.41±1.66) scores vs.(9.83±0.53) scores, t=5.40, P<0.001] in the respiratory morbidity group.The differences were statistically significant.There were more cases with maternal complications in the respiratory morbidity group that in the control group (66.7% vs.58.6%, χ2=4.877, P=0.027), but no difference in various complications between 2 groups was observed ( P>0.05). In the respiratory morbidity group, the most frequent complications were maternal hypertension and preeclampsia (27.8% vs.22.6%, χ2=2.728, P=0.099). There were no differences between 2 groups in gestational age, birth weight and birth length (all P>0.05). There were more infants small for gestational age and large for gestational age in the respiratory morbidity group than in the control group (18.8% vs.14.1%, 6.3% vs.2.4%, χ2=8.960, P=0.011). The duration of hospitalization of the respiratory morbidity group was significantly longer than that of the control group [(9.00±4.42) d vs.(6.82±4.19) d, t=6.676, P<0.001] since the infants with respiratory morbidity needed to be hospita-lized. Conclusions:Respiratory diseases occur in about 1/4 of late-preterm infants.Infants who are delivered by cesarean section and whose mothers are complicated with the maternal hypertension and preeclampsia should be monitored closely.Respiratory support should be provided for infants not appropriate for gestational age who are more likely to suffer from respiratory diseases, so that they can successfully pass through the transition period.