Objective To establish different kinds of reduced size liver transplantation model of rats， and to explorethe optimal marginal size of liver graft in orthotopic liver transplantation， in purpose of providing a kind of animal modelfor the study about mechanism and prevention measures of small-for-size syndrome. Methods One hundred and ninety-two rats were randomly divided into whole liver graft transplantation group （underwent whole liver graft transplantation），half liver graft transplantation group （the median lobe and right lobe of the liver were selected to be the graft）， small size liver graft transplantation group （the median lobe of the liver was selected to be the graft）， and extra-small size liver graft transplantation group （the median lobe and left lobe of the liver were reduced， and remained lobes were selected to be the graft）， each group enrolled 48 rats. After liver graft transplantation， 24 rats of each group were selected to observe the survival situation， 12 rats of each group were selected to measure portal venous pressure at time point of before operation，and 5， 15， 30， 45， and 60 minutes after transplantation. The other 12 rats of each group were test the level of alanine aminotransferase （ALT）. Results Seven-day survival rate of the whole liver graft transplantation group， half liver graft transplantation group， small size liver graft transplantation group， and extra-small size liver graft transplantation group was 100% （24/24）， 87.5% （21/24）， 37.5% （9/24）， and 0 respectively. Portal venous pressure of whole liver graft trans-plantation group was stable after opening the portal vein， although there was slight increase at prophase in half liver graft transplantation group， and then the portal venous pressure would let down， keeping stable at the later stage. But in small size liver graft transplantation group and extra-small size liver graft transplantation group， the portal venous pressure incr-eased and got the top at 15 minutes after opening the portal vein， and then induced， keeping stable during the 45-60 minutes.Portal venous pressure at the point of 5 （r=-0.942）， 15 （r=-0.947）， 30 （r=-0.900）， 45 （r=-0.825）， and 60 （r=-0.705）minutes after opening the portal vein were significantly related to liver graft size （P＜0.001）. The levels of ALT in wholeliver graft transplantation group and half liver graft transplantation group were both lower than those of small size livergraft transplantation group and extra-small size liver graft transplantation group （P＜0.05）， and levels of ALT in small size liver graft transplantation group was lower than extra-small size liver graft transplantation group too （P＜0.05）. Levelof ALT at 24 hours after transplantation were significantly related to liver graft size （r=-0.685， P＜0.001）. Conclusions The minimum graft volume/standard liver volume （GV/SLV） in reduced size liver transplantation in rat is 50%. The liver graft whose GV/SLV is 30%-35% should be considered as marginal size liver graft， and the liver graft whose GV/SLV less than 30% should be considered as extra-small size liver graft in the rat.
【Abstract】Objective To review the recent advances in the use of marginal liver in liver transplantation. Methods The literatures of recent years on the use of marginal liver for liver transplantation were reviewed and summarized.Results The donors with older age, hemodynamic instability, long stay in the intensive care unit and fatty liver are significantly clinical marginal liver donors.Conclusion Though the use of marginal liver donors negatively influences the results of liver transplantation, marginal liver expands the liver source for liver transplantation with a good result.
To show that a new drug is better than, as good as, or no worse than that of a known effective drug. Theoretically, it is necessary to confirm the efficacy of a treatment, but the current practice of clinical trial suggests that there exists many problems in its confirmation including the objectives of clinical investigation vary based on the fact that more and more clinical trials use active controls. Applied statistical methods have to adapt to these changes. In this paper, we illustrated some statistical issues of confirming efficacy in clinical trials, including its conditions, the determination of clinical margin, the forms of the null and alternative hypothesis and confidence intervals, the choice of endpoints and some miscellaneous considerations. We bly suggests that it is necessary to make biostatisticians and clinical trialists understand the importance of using the right statistical methods when investigating clinical trials. We also think these methods introduced in the paper may provide some help in trial design and evaluation.
Objectives To systematically review the influence of positive margin on outcome after partial nephrectomy (PN). Methods CCRCT, PubMed, EMbase, Sinomed, WanFang Data and CNKI databases were electronically searched to collect clinical studies on influence of positive margin on outcome after PN from inception to December 31st, 2019. Two reviewers independently screened literature, extracted data and assessed risk of bias of included studies, then, meta-analysis was performed by using RevMan 5.4 software. Results A total of 22 cohort studies involving 20 822 patients were included. The results of meta-analysis showed that positive margin after PN could increase the rate of postoperative local recurrence (OR=4.18, 95%CI 2.88 to 6.05, P<0.000 01), distant metastasis (OR=5.28, 95%CI 2.84 to 9.81,P<0.000 01) and total mortality (OR=1.54, 95%CI 1.19 to 1.99,P=0.0010). However, there were no differences on overall survival (OR=0.64, 95% CI 0.34 to 1.19, P=0.16), distant metastasis free survival (OR=0.70, 95%CI 0.26 to 1.84, P=0.46), cancer specific survival (OR=0.43, 95% CI 0.06 to 3.01, P=0.40) and disease-free survival (OR=0.81, 95%CI 0.35 to 1.85, P=0.61) between two groups. Conclusions Current evidence suggests that positive margin after PN may be associated with tumor progression, however, it may not affect patient survival. Due to limited quality and quantity of the included studies, more high quality studies are required to verify above conclusions.
ObjectiveTo evaluate the effect of statins on amino-terminal brain natriuretic peptide (NT-proBNP), grade of New York Heart Association (NYHA), and ejection fraction (EF) in patients with chronic heart failure (CHF) using marginal structural model. MethodsA total of 297 patients with CHF from two medical centers in Shanxi province were sequentially enrolled from January 2018 to December 2020. The medical records were collected. Confounding factors were analyzed by t-test, Chi-square test and logistic regression. The random forest algorithm was used to estimate the weight of inverse probability. The marginal structural model was applied to evaluate the effects of statins. ResultsUsing logistic regression to exclude the influence of baseline confounders, the results showed that statins had no significant effect on the level of NT-proBNP in patients with CHF. The marginal structural model which excluded the influence of baseline confounders, time-dependent confounders and treatment conversion factors showed that statins significantly reduced NT-proBNP (OR=0.699, 95%CI 0.528 to 0.926, P=0.012). Statins had no significant effects on NYHA and EF. ConclusionStatins can effectively reduce the level of NT-proBNP in patients with CHF.
ObjectiveTo explore the method of constructing time-dependent variables of clinical prognostic model, and to combine marginal structure model with clinical prognostic model to provide a more accurate tool for individualized prognostic assessment of patients. MethodsThrough data simulation, a training dataset with sample size of 7 000 and a validation dataset with sample size of 3 000 were constructed, and the predictive efficacy of ignoring treatment model, baseline no-treatment model, baseline treatment prediction model and marginal structure prediction model were respectively compared under different follow-up times and different situations. ResultsAt 2 follow-up time points, there was no significant difference between the marginal structure prediction model and the baseline treatment prediction model, but they were higher than the neglected treatment model and the baseline no treatment model. At 5 follow-up time points, the prediction ability of the marginal structure prediction model was significantly higher than that of the other three prediction models. ConclusionIn the case of time-dependent treatment in the observational cohort, the change of treatment after baseline should be considered when constructing the clinical prognosis model, otherwise the prediction accuracy of the prognosis model will be reduced.
Mucosa-associated lymphoid tissue (MALT) lymphoma is an indolent B cell derived non-Hodgkin's lymphoma. It is the main type of uveal lymphoma and is extremely rare. The pathogenesis of ocular MALT lymphoma remains unclear. It is now considered to be associated with many causes. The manifestations of primary uveal MALT lymphoma differ. So sometimes it is necessary to diagnose depending on diversity of auxiliary tests. Ultrasound examination shows typical low and homogeneous internal reflectivity, with blood flow signal. Optical coherence tomography, fundus imaging, fundus angiography, magnetic resonance imaging and positron emission tomography computerized tomography can assist diagnosing. Primary uveal MALT lymphoma is sensitive to radiation therapy, chemotherapy and biotherapy have positive influence too. The prognosis of uveal MALT lymphoma is good, but its early diagnosis is rather challenging. The nonspecific clinical manifestations and the rarity of the disease can confound the initial diagnosis, resulting in delayed treatments which may cause irreversible vision loss.