Objective:To investigate the variation of reference ranges of hemodynamic parameters in normal pregnancy and their relation to maternal basic characteristics.Methods:A total of 598 healthy pregnant women who underwent regular prenatal examination at the Third Affiliated Hospital of Guangzhou Medical University from January to December 2023 were prospectively enrolled, and noninvasive hemodynamic monitors were used to detect changes in hemodynamic parameters of the pregnant women with the week of gestation, including cardiac output (CO), stroke volume (SV), thoracic fluid content (TFC), systemic vascular resistance (SVR), mean arterial pressure (MAP), and heart rate (HR). Relationships between hemodynamic parameters and maternal basic characteristics, including age, height, and weight, were analyzed using restricted cubic spline.Results:(1) CO ( r=0.155, P<0.001), TFC ( r=0.338, P<0.001), MAP ( r=0.204, P<0.001), and HR ( r=0.352, P<0.001) were positively correlated with the week of gestation, and SV was negatively correlated with the week of gestation ( r=-0.158, P<0.001). There was no significant correlation between SVR and gestational age ( r=-0.051, P=0.258). (2) CO exhibited a positive correlation with maternal height and weight (all P<0.001). The taller and heavier of pregnant women, the higher their CO. A linear relationship was observed between maternal weight and SV, MAP and HR (all P<0.01). As maternal weight increased, SV, MAP and HR showed an upward trend. Furthermore, there was an inverse association between maternal age and SVR ( P<0.001). (3) There was a significant nonlinear association observed between TFC and body mass index during pregnancy ( P<0.05). Additionally, a nonlinear relationship was found between SVR and MAP in relation to maternal age (all P<0.05). Notably, when the age exceeded 31 years old, there was an evident upward trend observed in both SVR and MAP. Conclusions:The hemodynamic parameters of normal pregnant women are influenced by their height, body weight, and age. It is advisable to maintain a reasonable weight during pregnancy and give birth at an appropriate age.

To lay a foundation for the type selection of the ambulance helicopter. The type selection was explored from the aspects of platform selection, rescue environment and service requirements, analyzing the rescue in the helicopter and the tendency of the ambulance helicopter in foreign countries and China. The types of the am-bulance helicopter were determined as the specific and modified ambulances, with the considerations such as operation environment, flight performance, cabin structure, onboard equipment, cabin configuration, fixation device and protection. Specific ambulance helicopter is supposed to be based on small- or mediate-sized platform, while the modi-fied ambulance helicopter is supposed to be based on large or heavy platform.

Objective To investigate the relationship between the TRAb-producing cell precursors and different clinical stages of Graves' disease.Methods Peripheral lymphocytes were infected with Epstein-Barr virus,a kind of lymphocyte precursor stimulator,and were stimulated to produce TRAb.Results Of the total wells containing Ig-producing B cell precursors,there were 34.6% and 29.1% from 2 untreated patients,30% from 1 relapsing patient and only 1.3% and 3.8% from 2 healthy controls that secreted TRAb,respectively.As for the wells containing B cell precursors from 2 remission patients with undetectable TRAb in circulation,the percentage (10.7%) of TRAb-containing wells from one was higher than that from the other (5.3%).And the latter had similar percentage of TRAb-positive wells with the controls.The isotype of TRAb in supernatants of our EBV-transformed B lymphocytes was predominantly IgM.Conclusion The frequencies of TRAb-specific precursors were different at three distinct clinical stages of the disease.

Objective　 To observe the effect of leptin on osteoblast. Methods　 Human osteoblast primary culture was carried out, and the morphology and function of osteoblast were observed. The effects of different levels of leptin on osteoblast in different days were assessed by MTT colorimetry. Osteocalcin production was measured also. Results　 Human osteoblasts were fusiform in shape and were positive for alkaline phosphatase by histochemical staining, positive for osteocalcin by immunofluorescence staining, and positive by Alizarin Reds staining after mineralized upon supplementation with ascorbate and β-glycerophosphate. On the first, second and third days, the prolifertion of osteoblast， cultured with different concentrations of leptin， had no changes. The leptin-stimulated synthesis of osteocalcin of cells was found to be dose-dependent (P＜0.05), but not time-dependent (P＞0.05). Conclusion　 The above data indicated that there were no evidences for the effects of leptin on the proliferation of human osteoblast, but leptin could enhance the function of human osteoblast.