ObjectiveTo analyze the stress contribution of different cement volume to the adjacent vertebral endplates in percutaneous kyphoplasty (PKP) so as to explore the possible mechanism of adjacent vertebral fractures after PKP.Methods The three-dimensional finite element model of osteoporotic thoracolumbar vertebral compression fractures was established to simulate vertebral body partial restoration (80％) with PKP.During the process,two doses of bone cement ( polymethylmethacrylate,PMMA) were filled in the vertebral body (4.0 ml bone cement filling 15％ of the vertebral body volume and 8.0 ml bone cement filling 30％ of the vertebral body volume).Endplate stress under conditions of axial compression,flexion and extension was analyzed. ResultsRegarding the two filling doses in PKP,the adjacent vertebral endplate stress under the above-mentioned conditions was all increased at T11 and L1 vertebral body compared with that before operation.Meanwhile,endplate stress had positive correlation with the cement volume and the stress concentrated largely in the anterior and middle parts of endplate.ConclusionsThe stress of adjacent vertebral endplate is positively correlated with cement volume,with anterior and middle parts of endplate as the stress concentration.The probability of adjacent vertebral fractures shows a rising trend with the increase of cement volume in PKP.

AIM: To observe the effects of methionine-induced hyperhomocysteinemia on protein C(PC), antithrombin-Ⅲ (AT-Ⅲ) and von willebrand factor (vWF). METHODS:Eighteen New Zealand rabbits were randomized as methionine group (group M,n=9) and control(group C,n=9), which were fed with methionine-rich diet(600 mg/d) and regular diet respectively for sixteen weeks.By the end of sixteen weeks,the serum biochemistry and PC,AT-Ⅲ and vWF in plasma were determined and vWF expression of endothelial cells of aorta were examined.RESULTS:In group M, the levels of methionine(29.97?5.34 ?mol/L) and homocysteine(13.30?2.19 ?mol/L) in serum were signifficantly higher than those(14.48?1.97 ?mol/L and 5.36?1.19 ?mol/L, respectively,P

AIM: To observe the oxidative modification of low density lipoprotein iinduced by hyper homocysteinaemia following application of methionine. METHODS: Thirty two rabbits were randomized as group methionine(group M, n =9), group cholesterol (group Ch, n= 9), group methionin+cholesterol (group M+Ch, n= 9) and control group (group C, n= 5).In group M, Ch and M+Ch, the animals were fed with the food containing 3% methionine, 3.75% cholesterol and 3% methionine+3.75% cholesterol, respectively. By the end of sixteen weeks, the blood were taken and the measurements were carried out. RESULTS: Following application of methionine, the levels of hyperhomocysteine, ox-LDL and TBARS in group M and group M+Ch were significntly higher than those of group C and group Ch ( P

d-α-Tocopheryl polyethylene glycol 1000 succinate (TPGS, also known as vitamin E-TPGS) is a biodegradable amphiphilic polymer prepared by esterification of vitamin E with polyethylene glycol (PEG) 1000. It is approved by the US Food and Drug Administration (FDA) and has found wide application in nanocarrier drug delivery systems (NDDS). Fully characterizing the in vivo fate and pharmacokinetic behavior of TPGS is important to promote the further development of TPGS-based NDDS. However, to date, a bioassay for the simultaneous quantitation of TPGS and its metabolite, PEG1000, has not been reported. In the present study, we developed such an innovative bioassay and used it to investigate the pharmacokinetics, tissue distribution and excretion of TPGS and PEG1000 in rat after oral and intravenous dosing. In addition, we evaluated the interaction of TPGS with cytochromes P450 (CYP450s) in human liver microsomes. The results show that TPGS is poorly absorbed after oral administration with very low bioavailability and that, after intravenous administration, TPGS and PEG1000 are mainly distributed to the spleen, liver, lung and kidney before both being slowly eliminated in urine and feces as PEG1000. In vitro studies show the inhibition of human CYP450 enzymes by TPGS is limited to a weak inhibition of CYP3A4. Overall, our results provide a clear picture of the in vivo fate of TPGS which will be useful in evaluating the safety of TPGS-based NDDS in clinical use and in promoting their further development.

Irinotecan is an anticancer topoisomerase I inhibitor that acts as a prodrug of the active metabolite, SN-38. Unfortunately, the limited utility of irinotecan is attributed to its pH-dependent stability, short half-life and dose-limiting toxicity. To address this problem, a novel trivalent PEGylated prodrug (PEG-[Irinotecan]₃) has been synthesized and its full-profile pharmacokinetics, antitumor activity and toxicity compared with those of irinotecan. The results show that after intravenous administration to rats, PEG-[Irinotecan]₃ undergoes stepwise loss of irinotecan to form PEG-[Irinotecan]_3‒x (x = 1,2) and PEG-[linker] during which time the released irinotecan undergoes conversion to SN-38. As compared with conventional irinotecan, PEG-[Irinotecan]₃ displays extended release of irinotecan and efficient formation of SN-38 with significantly improved AUC and half-life. In a colorectal cancer-bearing model in nude mice, the tumor concentrations of irinotecan and SN-38 produced by PEG-[Irinotecan]₃ were respectively 86.2 and 2293 times higher at 48 h than produced by irinotecan. In summary, PEG-[Irinotecan]₃ displays superior pharmacokinetic characteristics and antitumor activity with lower toxicity than irinotecan. This supports the view that PEG-[Irinotecan]₃ is a superior anticancer drug to irinotecan and it has entered the phase II trial stage.

ObjectiveTo investigate the value of different noninvasive diagnostic models in the diagnosis of esophageal and gastric varices since there is a high risk of esophageal and gastric varices in patients with compensated hepatitis B cirrhosis and significant portal hypertension， and to provide a basis for the early diagnosis of esophageal and gastric varices. MethodsA total of 108 patients with significant portal hypertension due to compensated hepatitis B cirrhosis who attended Guangdong Provincial Hospital of Traditional Chinese Medicine from November 2017 to November 2023 were enrolled， and according to the presence or absence of esophageal and gastric varices under gastroscopy， they were divided into esophageal and gastric varices group （GOV group） and non-esophageal and gastric varices group （NGOV group）. Related data were collected， including age， sex， imaging findings， and laboratory markers. The chi-square test was used for comparison of categorical data between groups； the least significant difference t-test was used for comparison of normally distributed continuous data between groups， and the Mann-Whitney U test was used for comparison of non-normally distributed continuous data between groups. The receiver operating characteristic （ROC） curve was plotted to evaluate the diagnostic value of five scoring models， i.e.， fibrosis-4 （FIB-4）， LOK index， LPRI， aspartate aminotransferase-to-platelet ratio index （APRI）， and aspartate aminotransferase/alanine aminotransferase ratio （AAR）. The binary logistic regression method was used to establish a combined model， and the area under the ROC curve （AUC） was compared between the combined model and each scoring model used alone. The Delong test was used to compare the AUC value between any two noninvasive diagnostic models. ResultsThere were 55 patients in the GOV group and 53 patients in the NGOV group. Compared with the NGOV group， the GOV group had a significantly higher age （52.64±1.44 years vs 47.96±1.68 years， t=0.453， P<0.05） and significantly lower levels of alanine aminotransferase ［42.00 （24.00 — 17.00） U/L vs 82.00 （46.00 — 271.00） U/L， Z=-3.065， P<0.05］， aspartate aminotransferase ［44.00 （32.00 — 96.00） U/L vs 62.00 （42.50 — 154.50） U/L，Z=-2.351， P<0.05］， and platelet count ［100.00 （69.00 — 120.00）×10⁹/L vs 119.00 （108.50 — 140.50）×10⁹/L， Z=-3.667， P<0.05］. The ROC curve analysis showed that FIB-4， LOK index， LPRI， and AAR used alone had an accuracy of 0.667， 0.681， 0.730， and 0.639， respectively， in the diagnosis of esophageal and gastric varices （all P<0.05）， and the positive diagnostic rates of GOV were 69.97%， 65.28%， 67.33%， and 58.86%， respectively， with no significant differences in AUC values （all P>0.05）， while APRI used alone had no diagnostic value （P>0.05）. A combined model （LAF） was established based on the binary logistic regression analysis and had an AUC of 0.805 and a positive diagnostic rate of GOV of 75.80%， with a significantly higher AUC than FIB-4， LOK index， LPRI， and AAR used alone （Z=-2.773，-2.479，-2.206， and-2.672， all P<0.05）. ConclusionFIB-4， LOK index， LPRI， and AAR have a similar diagnostic value for esophageal and gastric varices in patients with compensated hepatitis B cirrhosis and significant portal hypertension， and APRI alone has no diagnostic value. The combined model LAF had the best diagnostic efficacy， which provides a certain reference for clinical promotion and application.