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Background: Peak oxygen pulse (O2Ppeak) can reflect the condition of cardiovascular function and provide supplementary information for maximal oxygen uptake, but its direct measurement requires the precise instruments under the guidance of professionals, and the subjects should strive to the state of exhaustion. Objectives: The aim of the present cross-sectional study was to establish a prediction equation to estimate O2Ppeak of Chinese adults aged 20-39, from routine measures of anthropometry and cardiovascular function. Methods: 252 adults (20-39 years old) were recruited and randomly allocated to the validation group (n = 226) and the cross-validation group (n = 26). To be included in the study, subjects were required to be healthy, none-professional sports experience (healthy individuals who are not athletes or have had experience as athletes), and no medication taken recently. Subjects with cardiovascular diseases, lung disease and musculoskeletal diseases were excluded. The subjects' anthropometric and cardiovascular variables were measured and each subject performed a maximal exercise test on an electromagnetic cycle ergometer. Results: The O2Ppeak estimated equation was developed using multiple linear regression models, O2Ppeak = 30.394 + 0.083 x body mass (kg) - 0.090 x resting heart rate (bpm) - 0.157 x age (years) - 2.710 x gender (1 = male, 2 = female) - 0.035 x systolic blood pressure (mmHg). The equation had the coefficient of determination (R2) = 0.804 and the standard error of estimate (SEE) = 1.619 ml/beat. An ANOVA and Akaike's information criterion (AIC) were tested. Bland-Altman graphs were plotted to examine the distribution of bias. Cross-validation estimated O2Ppeak and directly measured O2Ppeak did not show significant difference while had a strong positive correlation (r = 0.89, p < 0.001). Conclusions: The established equation has high effectiveness and reliability to predict O2Ppeak of adults aged 20-39.
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Objective:Chemiluminescence immunoassay was used to detect the levels of anticardiolipin antibody (aCL) -IgA/IgG/IgM and anti-β2-glycoprotein Ⅰ antibody (aβ2GPⅠ) -IgA/IgG/IgM in healthy non-pregnant and pregnant women to explore the changes of antiphospholipid antibody in different pregnancy periods.Methods:This prospective study was conducted in Shandong Provincial Maternal and Child Health Care Hospital Affiliated to Qingdao University, involving normal pregnant women who underwent prenatal examination and healthy non-pregnant women with no history of adverse pregnancy who underwent progestational eugenic health examination from April 2020 to August 2021. The levels of aCL-IgA/IgG/IgM and aβ2GPⅠ-IgA/IgG/IgM were detected using BIO-FLASH chemiluminescence immunoassay analyzer and P95 as well as P99 were calculated, respectively. The difference in the six data between non-pregnant and pregnant women was compared using Mann-Whitney U test. Kruskal-Wallis H test was used to compare the change of each antibody in different pregnancy periods and Spearman correlation was used to analyze the correlation between different trimester and the levels of aCL-IgA/IgG/IgM and aβ2GPⅠ-IgA/IgG/IgM. Results:A total of 454 cases met the inclusion criteria, and 435 cases were included in the analysis after excluding 19 cases, among them 110 were non-pregnant women and 325 were pregnant women, including 110 cases in the first trimester (≤13 +6 weeks), 110 cases in the second trimester(14 +0-27 +6 weeks), and 105 cases in the third trimester (≥28 weeks). P99 value of aCL-IgA/IgG/IgM and aβ2GPⅠ-IgA/IgG/IgM in the non-pregnant women were 7.31, 14.70, 7.92, 3.58, 13.60, and 4.95 CU, which in the pregnant women were 5.90, 12.78, 5.70, 1.60, 10.65, and 3.90 CU, and were all lower than the cut-off value of 20 CU that given by the analyzer manufacturer. The levels of aCL-IgA/IgG/IgM, and aβ2GPⅠ-IgG/IgM in the pregnant women were significantly decreased comparing with the non-pregnant women [aCL-IgA: 1.90 CU (1.40-2.70 CU) vs 2.90 CU (2.20-3.83 CU), Z=－7.14; aCL-IgG: 3.00 CU (2.20-4.50 CU) vs 6.10 CU (4.20-7.83 CU), Z=－10.26; aCL-IgM: 1.40 CU (1.10-2.30 CU) vs 2.65 CU (2.08-3.73 CU), Z=－8.87; aβ2GPⅠ-IgG: 3.50 CU (2.60-4.90 CU) vs 4.75 CU (3.60-5.93 CU), Z=－5.45; aβ2GPⅠ-IgM: 0.70 CU (0.50-1.20 CU) vs 1.00 CU (0.60-1.53 CU) , Z=－3.73; all P<0.001]. The aCL-IgA level in the third trimester was higher than those in the first and second trimester (both P<0.05). The levels of aCL-IgG/IgM in the second trimester and aβ2GPⅠ- IgG in the second and third trimesters were significantly decreased than those in the first trimester (all P<0.05). Spearman analysis showed that aCL-IgG/IgM, aβ2GPⅠ-IgA/IgM had no significant correlation with the pregnancy period (the first, second and the third trimester) (all P>0.05). However, a weak correlation between the aCL-IgA, aβ2GPⅠ- IgG and the pregnancy period was observed ( r=0.28 and－0.49, both P<0.001) Conclusions:P99 value of aCL-IgA/IgG/IgM and aβ2GPⅠ-IgA/IgG/IgM levels in normal pregnant women and non-pregnant women are lower than the cut-off value of 20 CU given by the analyzer manufacturer. The levels of aCL-IgA/IgG/IgM and aβ2GPⅠ-IgG/IgM during pregnancy are lower than those before pregnancy and fluctuate with the pregnancy period, but have no significant correlation with the pregnancy period. The clinical diagnosis of antiphospholipid syndrome should be made according to the cut-off values of aCL-IgA/IgG/IgM and aβ2GPⅠ-IgA/IgG/IgM determined by each laboratory.
ABSTRACT
<p><b>OBJECTIVE</b>To understand the incidence and relevant affecting factors of infant vitamin K deficiency bleeding (VKDB) in Shandong Province.</p><p><b>METHODS</b>With stratified cluster sampling, 28 156 live newborns from five districts and six counties were surveyed for the condition of bleeding from their birth to 6 months based on standard diagnostic criteria. A 1:2 matched case-control study of VKDB was performed.</p><p><b>RESULTS</b>An overall incidence of VKDB was 3.27 per thousand in Shandong; higher in the rural areas (4.96 per thousand ) than in the urban areas (1.19 per thousand ). Most of the bleeding cases were breast-fed babies (about 95.57%) and incidence of VKDB in pre-term babies (22.52 per thousand ) was higher than that in term ones (2.96 per thousand ). Mothers' drug taking during pregnancy, asphyxia at birth, breast-feeding and illness within two weeks after birth were risk factors for it. Use of vitamin K after birth and bottle-feeding were protective factors for it.</p><p><b>CONCLUSIONS</b>Incidence of VKDB is higher in Shandong Province, as compared to other areas all over the country at the same time period. It is very important to prevent VKDB, focusing on high-risk babies in the rural areas, including those of preterm, breast-fed and suffering illness after birth.</p>