Melatonin activates autophagy via the NF-κB signaling pathway to prevent extracellular matrix degeneration in intervertebral disc

OBJECTIVE

This study investigated whether melatonin alleviates intervertebral disc degeneration (IVDD) by promoting autophagy through inhibiting the NF-κB signaling pathway.

METHODS

Magnetic resonance imaging (MRI), hematoxylin and eosin (H&E) staining and Safranin-O staining were used to measure disc degeneration in rat needle puncture IVDD models, and melatonin was injected intraperitoneally in the treated group to test its function. The expression of autophagy and extracellular matrix (ECM) degeneration related-markers were measured in the discs using immunohistochemistry. Transmission electron microscopy was used to evaluate the activation of autophagy in human nucleus pulposus (NP) tissues with different degenerated statuses. The expression of autophagy and disc degeneration related-markers were detected in NP cells by Western blot, RT-qPCR, and immunofluorescence analyses. NF-κB signaling pathway involvement was studied by lentivirus-mediated knockdown, Western blotting, and immunohistochemistry and immunofluorescence staining.

RESULTS

Melatonin prevented IVDD development in vivo and in vitro. Compared to non-degenerated disc tissues, degenerated human NP tissues showed a decrease in the autophagy-specific marker LC3B and the numbers of autophagosomes and autolysosomes, whereas the p62 level was increased; similar results were observed in rat IVDD models, indicating a negative correlation between autophagy and IVDD. Furthermore, both in vivo and in vitro studies found that melatonin application induced autophagy and reduced ECM disc degradation. Melatonin was also shown to regulate autophagy by inhibiting the NF-κB signaling pathway in vivo and vitro.

CONCLUSION

This study indicates that melatonin prevents IVDD by promoting autophagy, indicating its possible therapeutic potential for controlling the progression of IVDD.

ADMA mediates gastric cancer cell migration and invasion via Wnt/β-catenin signaling pathway

Objective

To explore the role of ADMA in gastric cancer.

Methods

The specimens of 115 gastric cancer patients were analyzed by ELISA and survival analysis. Functional assays were used to assess the effects of ADMA on gastric cancer cells. Experiments were conducted to detect the signaling pathway induced by ADMA in GC.

Results

Gastric cancer patients with high ADMA levels had poor prognosis and low survival rate. Furthermore, high level of ADMA did not affect the proliferation while promoted the migration and invasion of gastric cancer cell. Moreover, ADMA enhanced the epithelial–mesenchymal transition (EMT). Importantly, ADMA positively regulated β-catenin expression in GC and promoted GC migration and invasion via Wnt/β-catenin pathway.

Conclusions

ADMA regulates gastric cancer cell migration and invasion via Wnt/β-catenin signaling pathway and which may be applied to clinical practice as a diagnostic and prognostic biomarker.

Electronic supplementary material

The online version of this article (10.1007/s12094-020-02422-7) contains supplementary material, which is available to authorized users.

Characterization of carbapenem-resistant Klebsiella pneumoniae in a tertiary hospital in Fuzhou, China

Aims

The emergence of carbapenem‐resistant Klebsiella pneumoniae (CRKP) strains has led to increased mortality and morbidity rates. Tigecycline, a new class of broad‐spectrum glycyl‐tetracycline antibiotics, has been used to target multi‐ and pan‐drug‐resistant bacterial infections. This study aimed to assess the molecular characteristics of CRKP in a tertiary hospital, and its susceptibility to tigecycline, to create a reference for hospital infection control and clinical drug use.

Methods and Results

We retrieved patient clinical information and CRKP characterization from medical records and detected the MIC of tigecycline using the micro‐broth dilution method. Multi‐locus sequence typing was performed, and antibiotic resistance genes associated with CRKP were detected by qPCR. A total of 166 CRKP strains were detected in the sputum, urine and blood among intensive care unit patients (average age, 69·6 years). The most infrequently observed resistance genes were amikacin resistance genes, followed by tobramycin resistance genes. KPC‐2, CTX‐M9 and CTX‐M1 were the most frequently detected resistance genes.

Conclusions

No strain was resistant to tigecycline (MIC ≥ 8 µg ml⁻¹). Twenty‐four sequence types were identified, with ST11 being the most common type.

Significance and Impact of the Study

Clinicians and infection control experts should be aware of CRKP prevalence to facilitate clinical treatment and improve nosocomial infection control.

[Fitting and forecasting the trend of COVID-19 by SEIR(+CAQ) dynamic model]

Objectives: Fitting and forecasting the trend of COVID-19 epidemics. Methods: Based on SEIR dynamic model, considering the COVID-19 transmission mechanism, infection spectrum and prevention and control procedures, we developed SEIR(+CAQ) dynamic model to fit the frequencies of laboratory confirmed cases obtained from the government official websites. The data from January 20, 2020 to February 7, 2020 were used to fit the model, while the left data between February 8-12 were used to evaluate the quality of forecasting. Results: According to the cumulative number of confirmed cases between January 29 to February 7, the fitting bias of SEIR(+CAQ) model for overall China (except for cases of Hubei province), Hubei province (except for cases of Wuhan city) and Wuhan city was less than 5%. For the data of subsequent 5 days between February 8 to 12, which were not included in the model fitting, the prediction biases were less than 10%. Regardless of the cases diagnosed by clinical examines, the numbers of daily emerging cases of China (Hubei province not included), Hubei Province (Wuhan city not included) and Wuhan city reached the peak in the early February. Under the current strength of prevention and control, the total number of laboratory-confirmed cases in overall China will reach 80 417 till February 29, 2020, respectively. Conclusions: The proposed SEIR(+CAQ) dynamic model fits and forecasts the trend of novel coronavirus pneumonia well and provides evidence for decision making.

Abstracts of published randomised controlled trials in Endodontics: Reporting quality and spin

AIMS

To assess the reporting quality of recently published randomised controlled trial (RCT) abstracts in Endodontics, to investigate factors associated with reporting quality, and to evaluate the existence and characteristics of spin. Spin refers to reporting strategies that distort study results and misguide readers.

METHODOLOGY

The PubMed database was searched to identify abstracts of RCTs in the field of Endodontics published during 2017 to 2018. Two authors assessed the reporting quality of each included abstract using the original 16-item CONSORT for Abstracts checklist, with the overall quality score (OQS, range: 0 to 16) being the primary outcome measure. For each individual item, a score of '1' was given if it was described adequately, and '0' if the description was inadequate. Linear regression analyses were conducted to identify factors associated with reporting quality. For the evaluation of spin, two authors selected parallel-group RCTs with a nonsignificant primary outcome from the included abstracts, and evaluated independently the existence and characteristics of spin among these abstracts.

RESULTS

A total of 162 abstracts were included for assessment of reporting, for which the mean OQS was 3.97 (SD, 1.30; 95 % CI, 3.77 to 4.17). According to multivariable analysis, origin from Europe (P=0.001) and reporting of the exact P value (P=0.020) were significantly associated with better reporting. Forty abstracts with statistically nonsignificant results for their primary outcome were included for spin evaluation, among which 34 (85.0%) had at least one type of spin. Thirty-two abstracts (94.1%) had spin in their conclusions section, and six abstracts (17.6%) had spin in the results section.

CONCLUSIONS

The reporting quality of RCT abstracts in Endodontics needs to be improved. The occurrence rate of spin in the sample of abstracts of RCTs in the field of Endodontics was high. Relevant stakeholders are recommended to be familiar with the CONSORT for Abstracts guideline and develop active strategies to ensure its implementation.

[Application of external diaphragm pacemaker combination with high-flow nasal cannula in offline patients with postoperative severe cerebral hemorrhage]

Objective: To investigate the offline clinical effect of external diaphragm pacemaker (EDP) combination with High-flow nasal cannula oxygen therapy in postoperative severe cerebral hemorrhage patients. Methods: A total of 123 severe postoperative severe cerebral hemorrhage patients with tracheotomy and mechanical ventilation (MV) were selected, who were admitted in NICU of PLA Rocket Force Characteristic Medical Center from October 2016 to December 2019. These patients were randomly divided into the High-flow nasal cannula (HFNC) group (n=63) and HFNC+EDP group (n=60). In the HFNC group, the HFNC was given to the patients who were off ventilator. The HFNC+EDP group was added on the basis of treatment in the HFNC group, once a day and 30 minutes each time. Results: Compared to the HFNC group, the oxygenation index (OI) of the HFNC+EDP group was higher in the next 1, 12, 24 and 48 hour [(209±15) mmHg vs (218±18) mmHg, (215±14) mmHg vs (222±17) mmHg, (223±13) mmHg vs (235±15) mmHg, (236±7) mmHg vs (257±12) mmHg,P<0.05]. The offline time was shorter [(13±3) d vs (12±3) d,P<0.05]. The excursion of diaphragm was higher [(1.94±0.08) cm vs (2.91±0.11) cm,P<0.05]. The length of stay in NICU was shorter [(33±14) d vs (28±9) d,P<0.05]. The Glasgow Coma Scale (GCS) was higher when being discharged from the NICU (5.9±2.1 vs 7.8±0.4, P<0.05) and the hospital (9.9±2.1 vs 11.0±2.0, P<0.05). Conclusions: EDP combination with HFNC can increase the excursion of diaphragm, shorten the offline time and length of stay in the NICU, thereby enhancing the early recovery and improving the prognosis.

Matrix-material dependence on the elongation of embedded gold nanoparticles induced by 4 MeV C60 and 200 MeV Xe ion irradiation

We report the elongation of embedded Au nanoparticles (NPs) in three different matrices, i.e. amorphous carbon (a-C), crystalline indium tin oxide (In_xSn_1-xO_z; ITO) and crystalline calcium fluoride (CaF₂), under irradiations of 4 MeV C₆₀ ⁺ cluster ions and 200 MeV Xe¹⁴⁺ ions. Under 4 MeV C₆₀ cluster irradiation, strong sputtering is induced in CaF₂ layer so that the whole the layer was completely lost at a fluence of 5 × 10¹³ ions cm^-2. Au NPs were partly observed in the SiO₂, probably due to the recoil implantation. Amorphous carbon (a-C) layer exhibits low sputtering loss even under 4 MeV C₆₀ irradiation. However, the elongation in a-C layer was low. While the ITO layer showed a certain decrease in thickness under 4 MeV C₆₀ irradiation, large elongation of Au NPs was observed under both 4 MeV C₆₀ and 200 MeV Xe irradiation. The ITO layer preserved the crystallinity even after large elongation was induced. This is the first report of the elongation of metal NPs in a crystalline matrix.

First Measurements of Electrons and Waves inside an Electrostatic Solitary Wave

Electrostatic solitary wave (ESW)-a Debye-scale structure in space plasmas-was believed to accelerate electrons. However, such a belief is still unverified in spacecraft observations, because the ESW usually moves fast in spacecraft frame and its interior has never been directly explored. Here, we report the first measurements of an ESW's interior, by the Magnetospheric Multiscale mission located in a magnetotail reconnection jet. We find that this ESW has a parallel scale of 5λ_{De} (Debye length), a superslow speed (99  km/s) in spacecraft frame, a longtime duration (250 ms), and a potential drop eφ_{0}/kT_{e}∼5%. Inside the ESW, surprisingly, there is no electron acceleration, no clear change of electron distribution functions, but there exist strong electrostatic electron cyclotron waves. Our observations challenge the conventional belief that ESWs are efficient at particle acceleration.

The Application of Non-linear Flow Resistance in Cerebral Artery: Compared with Windkessel Model based on Genetic Algorithm

Continuous blood pressure is measured from various extracranial body sites, with difference in amplitude and phase with intracranial blood pressure. Consequent influences on the accuracy of Windkessel model need further investigation. Between blood pressure and intracranial flow rate, a model with non-linear flow resistance (R-DT) was proposed and compared with the 3-element Windkessel (RCR) model. From the measured blood flow velocity in middle cerebral artery, the blood pressure was estimated by R-DT and RCR models respectively. The parameters in the models were optimized by genetic algorithm. The accuracies of R-DT and RCR models were compared based on their estimation errors to the measured blood pressure. The capacitance element in RCR model indicated limited ability to take the time shift into account. Compared with RCR model, R-DT model had less error (averaged relative error: 5.19% and 2.49% for RCR and RDT models). The non-linear flow resistance was applicable in simulating cerebral arteries.

[The application of intravoxel incoherent motion diffusion imaging and 3D arterial spin labeling perfusion imaging in the evaluation of acute cerebral infarction]

Objective: To investigate the clinical value of magnetic resonance (MR) intravoxel incoherent motion (IVIM) diffusion imaging and 3D pseudo continuous arterial spin labeling (3D-pcASL) perfusion imaging in the evaluation of acute cerebral infarction. Methods: MR images of 49 patients with unilateral acute cerebral infarction diagnosed and treated in Affiliated Yancheng Hospital of Southeast University Medical College from October 2015 to February 2019 were retrospectively analyzed. High signal infarction area (S(D)) on diffusion image slice with the biggest lesion level and abnormal perfusion area (S(CBF)) on the corresponding level were measured. The presence of ischemic penumbra (IP) was represented by S(CBF)> S(D), and patients were divided into group IP and group non-IP. Regions of interest were set on the infarction core, brain tissue near the edge of the lesion (BNL) and their corresponding contralateral regions. The values of apparent diffusion coefficient (ADC), true diffusion coefficient (D), perfusion related diffusion coefficient (D(*)), perfusion fraction (f) and cerebral blood flow (CBF) of each region of interest were recorded and relative values of infarction lesion to its contralateral region (rADC, rD, rD(*), rf, rCBF) were calculated. Differences of each parameter value between infarction core, BNL and their corresponding contralateral regions and of each relative parameter value between infarction core and BNL, and between the two groups were compared.The differential diagnostic efficacy of relative parameter value with differences between groups was analyzed by receiver operating characteristics (ROC) curve. The correlations of each relative parameter value of 3D-pcASL and IVIM sequences were analyzed. Results: The ADC, D, f and CBF values of infarction core were significantly lower than those of contralateral regions in both groups (all P<0.01). Among all parameters of BNL in both groups, only the CBF value of group IP was significantly lower than that of contralateral region ((27.58±3.53) vs (41.20±5.66) ml·100 g(-1)·min(-1), P<0.01). The rADC, rD, rf and rCBF of infarction core were significantly lower than those of BNL in both groups (all P<0.01). The rCBF of BNL in group IP was significantly lower than that in group non-IP (0.68±0.12 vs 0.97±0.15, P<0.01), and the area under the curve was 0.949, the optimal threshold was 0.823, and the youden index was 0.855 for identifying the two groups. Other relative parameters values of infarction core and BNL had no statistical difference between the two groups. There were positive correlations between rCBF and rADC, rD, rf (r=0.428,0.335,0.565) of infarction core, rADC and rD, rf (r=0.853,0.602) of infarction core, also rADC and rD (r=0.336) of BNL (all P<0.05). Conclusions: IVIM can effectively evaluate the difusion and perfusion information of acute cerebral infarction lesions. However, its perfusion related parameters are not as good as 3D-pcASL in IP evaluation, which should be flexibly selected according to the actual needs of patients' condition evaluation.

[Comparison of high-risk human papillomavirus infection rate and genotype distribution between Han and Mongolian women]

Objective: To understand the infection rate and genotype distribution of high risk-human papillomavirus (HR-HPV) and the detection rate of different grades of cervical lesions in Han and Mongolian women in China and provide evidence for the development of screening and vaccination strategies for the prevention and control of cervical cancer in different ethnic groups. Methods: In June 2017, a multicenter, population-based study for cervical cancer screening in low-resource settings in China was conducted in three rural areas: Xiangyuan and Yangcheng counties in Shanxi province, and Etuoke county in Inner Mongolia Autonomous Region. A total of 9 517 women aged 30-65 years were included in the study, and two cervical and vaginal secretion samples were collected from them for HPV and PCR-based HPV DNA tests. The positive samples in any of two tests were used for PCR-based HPV genotyping test by using Sansure-pioneered One-Step Fast Release technology. Women with positive results in any the HPV tests were referred for colposcopy and punch biopsy was given if cervical intraepithelial neoplasia lesion (low-grade lesion or worse) was suspected in colposcopy evaluation. Endocervical curettage was performed if women had an unsatisfactory colposcopy exam (the squamocolumnar junction was not completely visible). Pathological detection result was used as the golden standard of diagnosis. Results: HR-HPV infection rates in Han and Mongolian women were 21.83% (1 842/8 438) and 24.93% (269/1 079), respectively. There were statistical differences in HPV infection rates between the two ethnic groups (χ(2)=5.328, P=0.021). The detection rate of cervical intraepithelial neoplasia grade 1 in Mongolian women (2.83%) was higher than that in Han women (0.87%), and the difference was statistically significant (χ(2)=33.509, P<0.001). There were no significant differences in cervical intraepithelial neoplasia grade 2 or worse detection rate between the two ethnic groups [Mongolian woman: 1.04% (11/1 059), Han Woman: 0.95% (80/8 378), χ(2)=0.069, P=0.793]. Among Han and Mongolian women with cervical intraepithelial neoplasia grade 2 or worse, the three most common HR-HPV types were HPV16, HPV52 and HPV58. There was no significant difference for multiple infection rate between Han and Mongolian women (41.37% vs. 44.35%, χ(2)=0.764, P=0.382). Conclusions: The results show that HPV infection rate in Mongolian women was higher than that in Han women. Close attention should be paid to HPV16, 52 and 58 in the prevention and control of cervical cancer in Han and Mongolian women.

Discussion on Standardization of Forensic Assessment of Olfactory Dysfunction

Abstract

With the development of society, the improvement of living standards and the advancement of research methods, olfactory function has been paid more and more attention. Therefore, higher requirements for the forensic identification of olfactory function have also been put forward. Standardization construction of forensic medical examination and identification of olfactory dysfunction is urgently needed. Based on a comprehensive review of olfactory function and forensic assessment of olfactory dysfunction, this paper elaborates on problems related to the principles and timing of forensic assessment of olfactory dysfunction, the requirements of identification of traumatic olfactory dysfunction, the subjective and objective methods of examination of olfactory function. Strict control of the above issues is an important mean of standardization of forensic assessment of olfactory dysfunction.

[How to adjust confounders in studies on observational comparative effectiveness: (3) approaches on sensitivity analysis for confounder adjustment]

Confounders are difficult to avoid in studies on observational comparative effectiveness. It is often unclear whether the confounders have been completely eliminated after controlling the measured or unmeasured potential confounding effects or if sensitivity analysis is needed when using the specific statistical methods, under given circumstances. This manuscript summarizes and evaluates the confounding sensitivity analysis methods. Based on different studies, sensitivity analyses need to use different approaches. The traditional sensitivity analysis can be applied for the measured confounders. Currently, the relatively systematic sensitivity analyses for unmeasured confounders would include confounding function, bounding factor and propensity score calibration. Additionally, more investigations are associated with Monte Carlo and Bayesian sensitivity analysis. Reliability of the research conclusion thus may largely be improved when the sensitivity analysis results are consistent with the main analysis.

Prognostic value of the pretreatment albumin:globulin ratio combined with adult comorbidity evaluation 27 and TMN staging in patients with squamous cell carcinoma of the maxillary sinus

The albumin:globulin (A:G) ratio, adult comorbidity evaluation 27 (ACE-27), and TMN staging have been shown to be strong predictive indicators of the survival of patients with many types of tumours. We have investigated the prognostic value of pretreatment based on the A:G ratio combined with TMN staging and ACE-27 in patients with squamous cell carcinoma (SCC) of the maxillary sinus. We studied 196 patients, and the prognostic value was explored by univariate and multivariate Cox's hazards analysis. Multivariate analyses suggested that pretreatment A:G ratio was independently associated with overall survival (hazard ratio (HR) 1.542, 95% CI 1.219 to 1.991, p=0.002); disease-specific survival, (HR 1.499, 95% CI 1.197 to 1.842, p=0.001); and disease-free survival (HR 1.452, 95% CI 1.207 to 1.834, p<0.001). Additional prognostic factors shown in the survival analyses included ACE-27, pathological T stage, and pathological N stage. Pretreatment A:G ratio combined with ACE-27 and TMN staging were powerful prognostic indicators of outcome in patients with SCC of the maxillary sinus, which has potentially important ramifications for stratification of the disease in the future.

[Risk factors of human cystic echinococcosis in Shiqu County Sichuan Province: a case-control study]

OBJECTIVE

To identify the main risk factors of human cystic echinococcosis in Shiqu County, Sichuan Province, so as to provide the reference for the formulation of echinococcosis control strategies in Shiqu County.

METHODS

During the period from November 2015 through June 2017, the patients with cystic echinococcosis (case group) and healthy controls (control group) were randomly sampled from Shiqu County as the study subjects. A questionnaire survey was conducted to capture the study subjects'age, gender, ethnicity, occupation, religion, lifestyle, education level, number of household dogs, bovine and sheep, and density of dog feces in the courtyard. The major risk factors of human cystic echinococcosis were identified using a logistic regression model.

RESULTS

Univariate logistic regression analysis showed 7 risk factors with statistical significance between the case and control groups, and age, lifestyle, number of household bovine, number of household sheep, number of house-hold dogs, and the density of dog feces in the courtyard were included in the multivariate logistic regression model (OR = 1.026, 4.792, 1.067, 1.022, 1.709 and 1.095, respectively).

CONCLUSIONS

High age, pastoral nomadic lifestyle, high number of house-hold bovine, high number of household sheep, high number of household dogs and high density of dog feces in the courtyard are strongly associated with the riks of human cystic echinococcosis in Shiqu County.

MicroRNA-155 regulates cervical cancer via inducing Th17/Treg imbalance

OBJECTIVE

To explore the effect of microRNA-155 on cervical cancer and its underlying mechanism.

PATIENTS AND METHODS

Peripheral blood and cervical cancer tissues were collected. We used quantitative Real-time polymerase chain reaction (qRT-PCR) to detect expressions of microRNA-155, SOCS1, Th17-related genes (RORγt, IL-17A, IL-21, and IL-22), and Treg-related genes (foxp3, TGF-β, IL-10, and IL-35) in peripheral blood and cervical cancer tissues. Western blot was used to detect protein expressions of RORγt and foxp3. The proportions of Th17 and Treg cells in CD4+ T cells were measured by flow cytometry. Moreover, IL-17 expression was detected by enzyme-linked immunosorbent assay (ELISA).

RESULTS

MicroRNA-155 was overexpressed in peripheral blood and cervical cancer tissues of patients with cervical cancer compared with those of normal controls. Th17-related transcription factors and cytokines in cervical cancer tissues were remarkably elevated than those of normal controls, including RORγt, IL-17, and IL-6. Treg-related transcription factors and cytokines obtained the similar results. Besides, the proportion of Th17 cells in CD4+ T cells was higher in cervical tissues than that of normal controls. In vitro experiments suggested that overexpressed microRNA-155 can inhibit the expression of target gene SOCS1, promote the differentiation of Th17 and increase levels of IL-17, RORγt, and STAT3.

CONCLUSIONS

MicroRNA-155 is involved in the occurrence and progression of cervical cancer via inhibiting SOSC1 expression and inducing Th17/Treg imbalance.

Peritoneal dialysis effectively removes toxic substances and improves liver functions of liver failure patients

OBJECTIVE

Liver failure (LF) is a clinically complex disorder that characterizes with hepatic dysfunction. This study aimed at observing the therapeutic effects of peritoneal dialysis on liver function in LF patients.

PATIENTS AND METHODS

This study involves 62 patients diagnosed as LF hospitalized from February 2005 to December 2016. The 62 LF patients were randomly divided into 3 groups, including artificial liver applying plasma exchange group (PE, n = 28), peritoneal dialysis group (PD, n = 22), and conservative treatment group (CT, n=12). Laboratory indexes, including serum total bilirubin (TBiL), alanine aminotransferase (ALT), albumin (ALB), blood ammonia (AMMO), international normalized ratio (INR), and creatinine (Cr) were evaluated. Inflammatory cytokines, including tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), and procalcitonin (PCT) were examined using enzyme-linked immunosorbent assay (ELISA) kit.

RESULTS

Peritoneal dialysis significantly improves clinical outcomes, including decreased mortality, increased survival rate and total effective rate, compared to conservative treatment (p < 0.05). Peritoneal dialysis reduced hospitalization expenses compared to PE method and conservative treatment (p < 0.05). Peritoneal dialysis significantly removed toxic substances (including TBiL, AMMO, Cr) compared to conservative treatment (p < 0.05). The post-treatment level of Cr in peritoneal dialysis group was significantly lower compared to post-treatment level of Cr in PE group (p < 0.05). Peritoneal dialysis significantly improved liver function compared to conservative treatment (p < 0.05). Peritoneal dialysis prevented bleeding tendency compared to conservative treatment (p < 0.05). Peritoneal dialysis alleviated inflammatory response compared to conservative treatment (p < 0.05).

CONCLUSIONS

Peritoneal dialysis effectively removed toxic substances and improved liver functions of liver failure patients and with a lower therapeutic cost.

[Confounder adjustment in observational comparative effectiveness researches: (1) statistical adjustment approaches for measured confounder]

Observational comparative effectiveness studies have been widely conducted to provide evidence on additional effectiveness and to support randomized controlled findings in research. Although this type of study becomes more important over time, challenges related to the common biases which stemmed from confounders, are difficult to control. This manuscript summarizes some statistical methods used on adjusting measured confounders that often noticed in research, regarding the observational comparative effectiveness. Useful traditional methods would include stratified analysis, paired analysis, covariate model and multivariable model, etc.. Unconventional adjustment approaches such as propensity score and disease risk score methods may also be used in studies, for matching, stratification and adjustment. A good study design should be able to control confounders. The limitations of all the post hoc statistical adjustment methods should also be fully understood before being appropriately applied in practical events.