Biomechanics research of thoracolumbar vertebral burst fracture in impact damage / 中国骨伤

<p><b>OBJECTIVE</b>To investigate the damage characteristics and biomechanical mechanisms of the thoracolumbar vertebral bursh fracture during the impact loading.</p><p><b>METHODS</b>From September 2008 to October 2009, 10 fresh human thoracolumbar spine specimens were collected for experimental model and divided into two groups. Biomechanical static and dynamic impact strength test were performed respectively in two groups. The static and dynamic data from thoracolumbar vertebrae shock response in different loads were observated.</p><p><b>RESULTS</b>Thoracolumbar yield load was (5 280.00 +/- 354.2) N, yield displacement was (13.32 +/- 2.07) mm, the limit load was(6 590.00 +/- 249.20) N, ultimate displacement was (20.60 +/- 2.57) mm, load speed was 0.02 g, and the average limit load of dynamic mechanical properties of thoracic and lumbar vertebrae was (14 425.60 +/- 1101.52) N, the average reaction time load was (17.29 +/- 2.04) ms, the average of acceleration was (36.80 +/- 2.81) g, the dynamic displacement was (45.11 +/- 1.13) mm.</p><p><b>CONCLUSION</b>Thoracolumbar vertebral burst fracture is a serious injury caused by the release of high-energy moment, the role of biomechanical forces are in a pattern of pulse change, thoracic and lumbar vertebrae present with the viscoelastic properties of biological materials.</p>

Apoptosis of multiple myeloma cells induced by 8-Cl-cAMP in vitro / 中国实验血液学杂志

The study was aimed to investigate the possible effects of 8-chloroadenosine 3', 5'-monophosphate (8-Cl-cAMP) on the multiple myeloma cells. The multiple myeloma cell line RPMI8226 was used as in vitro models. The effect on growth inhibition of RPMI8226 cells was evaluated by cell growth and viability curve. DNA fragment was visualized by agarose gel electrophoresis. The amount of apoptosis cells was measured by flow cytometry. Meanwhile Western blot assay were used to detect the change of several key cell cycle regulatory proteins CDK2 and cyclin E in these cells before and after the treatment. The results showed that low dose 8-Cl-cAMP (1-30 micromol/L) inhibited the proliferation and viability of RPMI8226 cells significantly. Agarose gel electrophoresis of DNA revealed the apoptosis characteristic "ladder" pattern. Apoptosis was also confirmed by flow cytometry. In addition, 8-Cl-cAMP was able to inhibit the cell growth through modulating expression of cell cycle regulators CDK2 and cyclin E. It is concluded that 8-cl-cAMP inhibits the proliferation and induce apoptosis of multiple myeloma cells effectively.

Study on the risk factors of repeated abortion among unmarried adolescents / 中华流行病学杂志

<p><b>OBJECTIVE</b>To find out the rate of repeated induced abortion among unmarried abortion women and to study the relevant risk factors.</p><p><b>METHODS</b>From July to September 2005, we used the method of hospital based descriptive epidemiological study to investigate 2295 abortion women below 25 years of age in Beijing, Shanghai and Zhengzhou. Case-control study was used as the method. We considered the women with history of repeated abortion as case group (736 women) and considered the women without history of repeated abortion as control group (1559 women).</p><p><b>RESULTS</b>The mean age of respondents was 21.92 years with minimal age as 15 years. 17.2 % aborted women aged below 20 years with 32. 1% of them were ever having a history of previous induced abortion. Among 736 women with repeated abortion, 75.3 % of them had one time of induced abortion previously, 18.1% having two times, 4.2% having 3 times, 13 women having 4 times and 4 women having 5 times and one even with the maximum of having 8 times of previous abortion. In comparison with control group, the case group had higher rate among women whose first sex was below 18 years (16.2% vs. 9.4% , P<0.01). There were higher rates of women under following conditions: having exposed to sexual behavior for more than 3 years (33.6% vs. 6.6 % , P<0.01), having cohabited with male partner for over 1 year (64.6% vs. 23.9%, P <0.01), having regular sexual life (48.5 % vs. 37. 1%, P < 0.05), having multiple sexual partners (36.0% vs. 15.0%,P<0.01) having unwanted sex (6.0% vs. 3.9%, P<0.05), whose current pregnancy resulted from contraceptive failure (39.3% vs. 31.6%, P< 0.01), having a history of high-risk abortion (30.8% vs. 3.1%, P< 0.01) etc. In comparison with the control group, the case group showed higher rates of male partners not supporting this induced abortion, male partner not participating in decision-making on abortion and male partner not accompanying the female partners to seek for abortion service (rates of the three major factors in case group and in control group were 10.3% vs. 5.9%, P< 0.01, 30.3% vs. 24.0%, and 27.5% vs. 23.5%, P<0.01, respectively).</p><p><b>CONCLUSION</b>The rate of repeated induced abortion among unmarried abortion women was relatively high. The risk factors for females would include: younger age of sex debut, longer duration from the beginning of first sex to the current abortion, cohabitation, regular sexual life, multiple sexual partners, unwanted sex, contraceptive failure and high risk induced abortion. Meanwhile, unmarried but repeated abortion was related to the differences of gender between males and females and male partner's concern on induced abortion.</p>

Study on the occurrence of cesarean section (CS) and factors related to CS in China / 中华流行病学杂志

<p><b>OBJECTIVE</b>To find out the occurrence of cesarean section (CS) and to probe the factors associated with CS.</p><p><b>METHODS</b>Women with CS as "case group" and women without CS as "control group" were chosen in a case-control study.</p><p><b>RESULTS</b>Among 14 071 childbirth women, 6 421 had CS (case group) with the occurrence rate of 45.6% and 7 650 (54.4%) had normal delivery (control group). In comparison with the control group, the CS group had following several higher rates [with significant differences between case group and control group (P < 0.01)]: well-educated (78.9% vs 69.5%), white collar jobs (38.0% vs 32.3%), urban residents (79.1% vs 70.6%), high monthly income (>/= 500 Yuan) (81.0% vs 70.6%), of older age (>/= 25 years) (73.3% vs 63.0%), heavier baby weight (> 4 000 gram) (8.3% vs 2.9%), male babies (53.9% vs 51.4%), BMI of mother (> 24) (8.8% vs 4.8%), cephalopelvic disproportion (21.1% vs 0.9%), intrauterine asphysia (20.3% vs 6.7%), abnormality of force of labor (4.2% vs 2.7%), prolonged labor (2.9% vs 1.0%) and placenta previa (1.4% vs 0.4%). Our study also indicated that the higher the educational level was, the higher the rate of CS appeared; and the older the pregnant women was, the higher the rate of CS was. In CS group, over 70% primipara were over 24 years, and over 20% primipara had cephalopelvic disproportion and over 20% had intrauterine asphysia in CS group.</p><p><b>CONCLUSIONS</b>At present, the occurrence rate of cesarean section was rather high (45.6%) in China. The high rate of CS was more likely to associate not only with abnormal physiological/medical factors (eg. cephalopelvic disproportion, intrauterine asphysia, abnormality of force of labor, and prolonged labour, etc.), but also with some demographic factors as education, occupation, income and age, etc. It is necessary to take measures to reduce the unnecessary CS in China.</p>