Mean residual life cure models for right-censored data with and without length-biased sampling

We propose a semiparametric mean residual life mixture cure model for right-censored survival data with a cured fraction. The model employs the proportional mean residual life model to describe the effects of covariates on the mean residual time of uncured subjects and the logistic regression model to describe the effects of covariates on the cure rate. We develop estimating equations to estimate the proposed cure model for the right-censored data with and without length-biased sampling, the latter is often found in prevalent cohort studies. In particular, we propose two estimating equations to estimate the effects of covariates in the cure rate and a method to combine them to improve the estimation efficiency. The consistency and asymptotic normality of the proposed estimates are established. The finite sample performance of the estimates is confirmed with simulations. The proposed estimation methods are applied to a clinical trial study on melanoma and a prevalent cohort study on early-onset type 2 diabetes mellitus.

The mean residual life model for the right-censored data in the presence of covariate measurement errors

In this article, we consider the mean residual life regression model in the presence of covariate measurement errors. In the whole cohort, the surrogate variable of the error-prone covariate is available for each subject, while the instrumental variable (IV), which is related to the underlying true covariates, is measured only for some subjects, the calibration sample. Without specifying distributions of measurement errors but assuming that the IV is missing at random, we develop two estimation methods, the IV calibration and cohort estimators, for the regression parameters by solving estimation equations (EEs) based on the calibration sample and cohort sample, respectively. To improve estimation efficiency, a synthetic estimator is derived by applying the generalized method of moment for all EEs. The large sample properties of the proposed estimators are established and their finite sample performance are evaluated via simulation studies. Simulation results show that the cohort and synthetic estimators outperform the IV calibration estimator and the relative efficiency of the cohort and synthetic estimators mainly depends on the missing rate of IV. In the case of low missing rate, the synthetic estimator is more efficient than the cohort estimator, while the result can be reversed when the missing rate is high. We illustrate the proposed method by application to data from the patients with stage 5 chronic kidney disease in Taiwan.

[Construction of prediction model combined dual-energy CT quantitative parameters and conventional CT features for assessing the Ki-67 expression levels in invasive breast cancer]

Objective: To develop a model combined with dual-energy CT quantitative parameters and conventional CT features for evaluating the expression level of Ki-67 in invasive breast cancer. Methods: A total of 191 patients with histologically confirmed invasive breast cancer in Lishui Central Hospital from March 2019 to December 2020, were retrospectively enrolled, all of them were females, aged from 25 to 77 (53.2±11.3) years. All patients underwent preoperative non-contrast chest and contrast-enhanced Dual energy CT scans, and the normalized iodine concentration (NIC) of lesions on arterial and venous phase, spectral curve slope (λ_HU), and normalized effective atomic number (nZ_eff) were measured and calculated, and their conventional CT characteristics were assessed. According to the results of immunohistochemistry (IHC), the patients were divided into Ki-67 high expression group (n=129 patients) and low expression group (n=62 patients) level. The differences in clinical data, conventional CT characteristics and dual-energy CT quantitative parameters between the two groups were analyzed. The receiver operating characteristic curve (ROC) curve was conducted to assess the efficacy of each individual model and joint model in evaluating Ki-67 expression levels, and the area under the curve (AUC), sensitivity, specificity, and accuracy were calculated, respectively. Results: In the analysis of CT features, the longest diameter, shape and enhancement pattern of the tumor were significantly difference between the two groups (all P<0.05). The NIC, nZ_eff on the arterial phase and NIC, nZ_eff and λ_HU [M(Q₁,Q₃)] on the venous phase were higher in the high Ki-67 expression group compared to the low expression group [0.13 (0.12, 0.16) vs 0.11 (0.08, 0.14), 0.71 (0.70, 0.75) vs 0.70 (0.67, 0.72), 0.40 (0.32, 0.48) vs 0.23 (0.17, 0.32), 3.10 (2.58, 3.63) vs 2.86 (2.19, 3.48), 0.88 (0.85, 0.92) vs 0.85 (0.84, 0.86), all P<0.05]. The logistic regression model, which integrated significant conventional CT features and dual-energy CT quantitative parameters, demonstrated the highest diagnostic performance for assessing Ki-67 expression levels, with an AUC of 0.924, sensitivity of 88.37%, specificity of 83.87%, and accuracy of 86.91%; the AUC of the dual-energy CT parameter model was 0.908, sensitivity of 82.17%, specificity of 88.71%, and accuracy of 84.29%. Though the diagnostic efficacy was no significant difference (P=0.238), both models showed superior to the conventional CT feature model (all P<0.001). Conclusion: A dual-energy CT quantitative parameter combined with a conventional CT feature model was successfully constructed, which has a good evaluation performance on the expression level of Ki-67 in invasive breast cancer.

Maximum likelihood estimation for length-biased and interval-censored data with a nonsusceptible fraction

Left-truncated data are often encountered in epidemiological cohort studies, where individuals are recruited according to a certain cross-sectional sampling criterion. Length-biased data, a special case of left-truncated data, assume that the incidence of the initial event follows a homogeneous Poisson process. In this article, we consider an analysis of length-biased and interval-censored data with a nonsusceptible fraction. We first point out the importance of a well-defined target population, which depends on the prior knowledge for the support of the failure times of susceptible individuals. Given the target population, we proceed with a length-biased sampling and draw valid inferences from a length-biased sample. When there is no covariate, we show that it suffices to consider a discrete version of the survival function for the susceptible individuals with jump points at the left endpoints of the censoring intervals when maximizing the full likelihood function, and propose an EM algorithm to obtain the nonparametric maximum likelihood estimates of nonsusceptible rate and the survival function of the susceptible individuals. We also develop a novel graphical method for assessing the stationarity assumption. When covariates are present, we consider the Cox proportional hazards model for the survival time of the susceptible individuals and the logistic regression model for the probability of being susceptible. We construct the full likelihood function and obtain the nonparametric maximum likelihood estimates of the regression parameters by employing the EM algorithm. The large sample properties of the estimates are established. The performance of the method is assessed by simulations. The proposed model and method are applied to data from an early-onset diabetes mellitus study.

Trajectory of Estimated Glomerular Filtration Rate and Malnourishment Predict Mortality and Kidney Failure in Older Adults With Chronic Kidney Disease

Objective: The trajectory patterns of estimated glomerular filtration rates (eGFR) in chronic kidney disease (CKD) older adults with malnourishment and their association with subsequent patient outcomes have not been elucidated. We aimed to assess the eGFR trajectory patterns for predicting patient survival and kidney failure in the elderly without or with malnourishment.

Materials and Methods: Based on a prospective longitudinal cohort, CKD patients aged 65 years or older were enrolled from 2001 to 2013. Among the 3,948 patients whose eGFR trajectory patterns were analyzed, 1,872 patients were stratified by the absence or presence of malnourishment, and 765 patients were identified and categorized as having malnourishment. Four eGFR trajectory patterns [gradual decline (T0), early non-decline and then persistent decline (T1), persistent increase (T2), and low baseline and then progressive increase (T3)] were classified by utilizing a linear mixed-effect model with a quadratic term in time. The malnourishment was defined as body mass index < 22 kg/m², serum albumin < 3.0 mg/dL, or Geriatric Nutritional Risk Index (GNRI) < 98. This study assessed the effectiveness of eGFR trajectory patterns in a median follow-up of 2.27 years for predicting all-cause mortality and kidney failure.

Results: The mean age was 76.9 ± 6.7 years, and a total of 82 (10.7%) patients with malnourishment and 57 (5.1%) patients without malnourishment died at the end of the study. Compared with the reference trajectory T0, the overall mortality of T1 was markedly reduced [adjusted hazard ratio (aHR) = 0.52, 95% confidence interval (CI) 0.32–0.83]. In patients with trajectory, T3 was associated with a high risk for kidney failure (aHR = 5.68, 95% CI 3.12–10.4) compared with the reference, especially higher risk in the presence of malnourishment. Patients with high GNRI values were significantly associated with a lower risk of death and kidney failure, but patients with malnourishment and concomitant alcohol consumption had a higher risk of kidney failure.

Conclusions: Low baseline eGFR and progressively increasing eGFR trajectory were high risks for kidney failure in CKD patients. These findings may be attributed to multimorbidity, malnourishment, and decompensation of renal function.

The TVGH-NYCU Thal-Classifier: Development of a Machine-Learning Classifier for Differentiating Thalassemia and Non-Thalassemia Patients

Thalassemia and iron deficiency are the most common etiologies for microcytic anemia and there are indices discriminating both from common laboratory simple automatic counters. In this study a new classifier for discriminating thalassemia and non-thalassemia microcytic anemia was generated via combination of exciting indices with machine-learning techniques. A total of 350 Taiwanese adult patients whose anemia diagnosis, complete blood cell counts, and hemoglobin gene profiles were retrospectively reviewed. Thirteen prior established indices were applied to current cohort and the sensitivity, specificity, positive and negative predictive values were calculated. A support vector machine (SVM) with Monte-Carlo cross-validation procedure was adopted to generate the classifier. The performance of our classifier was compared with original indices by calculating the average classification error rate and area under the curve (AUC) for the sampled datasets. The performance of this SVM model showed average AUC of 0.76 and average error rate of 0.26, which surpassed all other indices. In conclusion, we developed a convenient tool for primary-care physicians when deferential diagnosis contains thalassemia for the Taiwanese adult population. This approach needs to be validated in other studies or bigger database.

Influence of Traditional Chinese Medicine on Medical Adherence and Outcome in Estrogen Receptor (+) Breast Cancer Patients in Taiwan: A Real-World Population-Based Cohort Study

BACKGROUND

Medical adherence is often higher in clinical trials than in real world practice. The aim of this study was to investigate the effects of traditional Chinese medicine (TCM) on medical adherence to hormonal therapy (HT) and survival outcome in ER (+) breast cancer patients in Taiwan.

SUBJECTS AND METHODS

Using a nationwide longitudinal population-based database, we enrolled patients with newly diagnosed ER-positive breast cancer who had received HT, and followed for up to 5 years (N = 872). Medication adherence in terms of medication possession ratios (MPR) and patient outcome were evaluated with or without TCM exposure. We applied logistic regression and Cox proportional hazards (PH) analysis to identify factors, including TCM exposure, associated with adherence to HT and mortality.

RESULTS

MPR to HT in general decreased over the 5-year period post breast cancer diagnosis. Both TCM and MPR to HT ≥ 80% were significantly associated with reduced risk of breast cancer-associated mortality. Subgroup analysis revealed that TCM annual visits ≥ 3 times with CHP prescription 1~90 days per year affected mortality reduction most significantly (HR: 0.26; 95% CI = 0.08-0.83; p < 0.05) compared to other TCM use. In contrast, using TCM (either short-term or long-term) was not associated with MPR in HT.

CONCLUSIONS

Our results supported the potential advantage of TCM on breast cancer-associated mortality, whereas TCM use does not compromise medical adherence to HT. This study offers important insights in integrative therapy for HT in patients with estrogen receptor (+) breast cancer.

Semiparametric mixture cure model analysis with competing risks data: Application to vascular access thrombosis data

The article is motivated by a nephrology study in Taiwan, which enrolled hemodialysis patients who suffered from vascular access thrombosis. After treatment, some patients were cured of thrombosis, while some may experience recurrence of either type (acute or nonacute) of vascular access thrombosis. Our major interest is to estimate the cumulative incidence probability of time to the first recurrence of acute thrombosis after therapy. Since the occurrence of one type of vascular access thrombosis precludes occurrence of the other type, patients are subject to competing risks. To account for the presence of competing risks and cured patients, we develop a mixture model approach to the regression analysis of competing-risks data with a cure fraction. We make inference about the effects of factors on both the cure rate and cumulative incidence function (CIF) for a failure of interest, which are separately specified in the logistic regression model and semiparametric regression model with time-varying and time-invariant effects. Based on two-stage method, we develop novel estimation equations using the inverse probability censoring weight techniques. The asymptotic properties of the estimators are rigorously studied and the plug-in variance estimators can be obtained for constructing interval estimators. We also propose a lack-of-fit test for assessing the adequacy of the proposed model and several tests for time-varying effects. The simulation studies and vascular access thrombosis data analysis are conducted to illustrate the proposed method.

Efficient solid-state Raman yellow laser at 579.5 nm

A highly efficient diode-pumped Nd:YVO₄/KGW Raman yellow laser is developed to produce a 6.8 W yellow light at 579.5 nm accompanied by a 3.2 W Stokes wave at 1159 nm under an incident pump power of 30 W. The intracavity stimulated Raman scattering with the shift of 768cm^-1 is generated by setting the polarization of the fundamental wave along the N_g direction of an N_p-cut KGW crystal. The Nd:YVO₄ gain medium is coated as a cavity mirror to reduce the cavity losses for the fundamental wave. More importantly, the KGW crystal is specially coated to prevent the Stokes wave from propagating through the gain medium to minimize the cavity losses for the Stokes wave.

Roles of nurses and National Nurses Associations in combating COVID-19: Taiwan experience

As the COVID‐19 pandemic continues to expand worldwide, Taiwan has effectively contained the spread domestically and protected its citizens after registering its first case relatively early on 21 January 2020. Proactive preparedness and deployment by the national government, timely evidence and experience‐based judgements and decision‐making, information transparency, rapid response, and effective communication and measures have all been critical to combating COVID‐19 in Taiwan. Nurses play a pivotal role in providing direct health care as well as providing contact tracing and care for the quarantined clients and community care services. The Taiwan Nurses Association and other nurses’ associations serve a vital leadership role in advocating for nurses, raising public awareness, enhancing nursing’s professional profile, and sharing experiences via national and international platforms. The implications for nursing and health policy are that we need to well prepare for any unpredicted emerging pandemic in the future. Providing adequate personal protective equipment and safe staffing should be the highest priority for the governments and policymakers around the world to combat pandemic successfully.

Impact of time-varying center volume on technique failure and mortality in peritoneal dialysis

BACKGROUND

Most studies on volume-outcome association used the number of patients at a particular period as the independent variable. However, peritoneal dialysis (PD) is a chronic treatment, and center volume usually changes over a patient's treatment period. Accordingly, this study used the time-varying center volume to explore the volume-outcome association in PD.

METHODS

We conducted a nationwide population-based retrospective cohort study, which included patients who began chronic PD between 2001 and 2010. The risk factors of 5-year technique failure and mortality were analyzed using cause-specific and subdistribution hazard models, respectively. The annual number of patients initiating PD in each patient's treatment center was modeled as a time-varying variable with four categories.

RESULTS

We included 9071 patients who started PD in 100 centers where the number of incident patients ranged from 1 to 107 patients per year (median, 25; interquartile range, 13-42). The estimated 5-year patient and technique survival rates were 64.7% and 66.6%, respectively. Being treated in centers in the largest volume category (the number of incident PD patients ≥43 per year) was associated with significantly lower cause-specific and cumulative hazards for technique failure. No association was found between facility volume and hazards of mortality.

CONCLUSIONS

Receiving PD in high-volume facilities was associated with a lower risk in technique failure. No association was found between facility volume and mortality risk.

[Prediction of short-term prognosis of hepatocellular carcinoma after TACE surgery based on MRI texture analysis technology]

Objective: To explore the feasibility of short-term efficacy prognosis prediction model for HCC patients undergoing transcatheter arterial chemoembolization (TACE) based on MRI-based radiomics technique. Methods: A total of 123 patients with liver cancer who received TACE treatment in Lishui Central Hospital from June 2016 to July 2018 were retrospectively collected, including 90 males and 33 females, with an average age of 24-83 (58±10) years. All the patients were pathologically confirmed as hepatocellular carcinoma and underwent MRI scan before surgery.All patients were followed up 3-4 months after TACE, and further divided into training group (n=85, 42 of which were effective and 43 cases were ineffective) and the validation group (n=38, 19 of which were effective and 19 were ineffective) according to the modified response evaluation criteria in solid tumors (mRECIST). There was no statistical difference in the general information between the two groups of patients, which was comparable. Then, preoperative T(2)WI images were used for radiomics analysis, texture parameters were screened based on R language, and short-term efficacy prediction model of TACE for training group and verification group was constructed. Results: T(2)WI image analysis of each patient received 396 different texture parameters, and further used Lasso dimensionality reduction and 10 times cross-validation screening to obtain 5 characteristic texture parameters, specifically stdDeviation, ClusterProminence_angle135_offset4, Correlation_angle135_offset4, Inertia_angle135_offset4, InverseDifferenceMoment_angle45_offset4. According to the above five texture parameters and their corresponding coefficient values, the corresponding radiomics scores (Radscore) were calculated, and the prediction models of the training group and the verification group were further constructed.It was found that the area under the ROC curve of the training group was 0.812 (95%CI: 0.722-0.901), the sensitivity and specificity were 83.7% and 69.0%, respectively. The area under the ROC curve of the validation group was 0.801 (95%CI:0.654-0.947), and the sensitivity and specificity were 89.5% and 63.2%, respectively. Conclusion: The constructed TACE prediction model in the present study has high prediction accuracy, sensitivity and specificity.The short-term efficacy prognosis prediction model for HCC based on MRI is constructed, stable and reliable.

Criterion for optimizing high-power acousto-optically Q-switched self-Raman yellow lasers with repetition rates up to 500 kHz

The criterion for optimizing the high-power acousto-optically ${Q}$Q-switched self-Raman yellow laser is originally explored for the repetition rate within 100-500 kHz. The minimum allowed value for the gate-open time is experimentally verified to be determined by the pulse buildup time. By using the minimum allowed gate-open time, the highest conversion efficiency can be achieved to raise the output power by approximately 20% in comparison with the conventional results. At a repetition rate of 200 kHz, the maximum output power at 588 nm can be up to 8.8 W at an incident pump power of 26 W. Furthermore, a practical formula is developed to accurately calculate the threshold pump power as a function of the gate-open time for a given repetition rate.

Compact efficient high-power triple-color Nd:YVO4 yellow-lime-green self-Raman lasers

A novel, to the best of our knowledge, approach is developed to realize a high-power compact efficient yellow-lime-green triple-color ${\rm Nd}:{{\rm YVO}_4}$Nd:YVO₄ self-Raman laser. The 588 nm yellow laser, the 559 nm lime laser, and the 532 nm green laser are converted from the 1064 nm fundamental wave and the 1176 nm Stokes Raman field. The simultaneous three-color operation is accomplished with three stages to step-by-step generate the 588 nm, 559 nm, and 532 nm lasers by using three different lithium triborate (LBO) crystals. By tuning the temperature of each individual LBO crystal, the 588 nm, 559 nm, and 532 nm output powers can be nearly the same and concurrently up to 2.4 W at the incident pump power of 30 W, corresponding to a conversion efficiency of 24% for the total output power.

[Percutaneous full-endoscopic removalof lumbar dumbbell tumors viatransforaminal approach]

Objective: To investigate the novel application and effectof Percutaneous Full-Endoscopic transforaminal approach for lumbar dumbbell tumors. Methods: A retrospective analysis of 12 cases of lumbar dumbbell tumors was conducted by Percutaneous full-endoscopic transforaminal approach in the Department of Neurosurgery, Fujian Medical University Union Hospital from Feb, 2018 to Jul, 2019. According to Eden classification, 5 cases in type Ⅲ and 7 cases in type Ⅳ. The Japanese Orthopaedic Association (JOA) score and Pain Visual analogue Scale (VAS) were used to compare the recovery of neurological function before and after surgery. Results: All the 12 tumors were completely removed in one stage. The pathological reports were all schwannomas (WHO grade Ⅰ). The VAS scores were significantly decreased compared with preoperative ones (P<0.001). The JOA scores were significantly improved without obvious complications and spinal instability. Median length of follow-up was 14 months with a range of 4 months to 20 months, there is no tumor recurrence and spinal instability. Conclusion: In the treatment of lumbar dumbbell spinal tumor, the full endoscopic transforaminal approach is a novel, safe and effective surgical procedure which removes the tumors intra-foramen and extra-foramen with less damage of spine, smaller possibility of instability and faster recovery.

Conditional maximum likelihood estimation in semiparametric transformation model with LTRC data

Left-truncated data often arise in epidemiology and individual follow-up studies due to a biased sampling plan since subjects with shorter survival times tend to be excluded from the sample. Moreover, the survival time of recruited subjects are often subject to right censoring. In this article, a general class of semiparametric transformation models that include proportional hazards model and proportional odds model as special cases is studied for the analysis of left-truncated and right-censored data. We propose a conditional likelihood approach and develop the conditional maximum likelihood estimators (cMLE) for the regression parameters and cumulative hazard function of these models. The derived score equations for regression parameter and infinite-dimensional function suggest an iterative algorithm for cMLE. The cMLE is shown to be consistent and asymptotically normal. The limiting variances for the estimators can be consistently estimated using the inverse of negative Hessian matrix. Intensive simulation studies are conducted to investigate the performance of the cMLE. An application to the Channing House data is given to illustrate the methodology.

Methotrexate might reduce ischemic stroke in patients with rheumatoid arthritis: a population-based retrospective cohort study

AIM

To investigate the effects of hydroxychloroquine, sulfasalazine and methotrexate on ischemic stroke in patients with rheumatoid arthritis (RA).

METHODS

This population-based retrospective cohort study included 7904 RA patients and 15 808 non-RA patients between 2000 and 2010. All of the participants were sampled from the National Health Insurance Research Database (NHIRD) of Taiwan. Using univariate analyses, these two groups of patients were compared to evaluate the differences in disease-modifying anti-rheumatic drugs usage and demographic variables. Cox proportional hazard models and Schoenfeld residuals test were performed to estimate the hazard ratios for ischemic stroke and proportional hazard assumptions of these drugs, respectively.

RESULTS

The mean age of participants was about 53 years old, and about 70% of RA patients were women. The hazard ratio for ischemic stroke was 1.21 (95% CI: 1.10-1.34; P < 0.01) in the case group compared with the control group, and this significant difference persisted throughout the 10-year period. With respect to RA patients, while hydroxychloroquine showed an insignificant protective effect on ischemic stroke, sulfasalazine and methotrexate were found out to have inconsistent effects during these 10 years. The proportional hazard assumption test of methotrexate at > 0.5 defined daily dose (8.75 mg/week) was violated at a significant level after adjustment (P = 0.0002).

CONCLUSIONS

At a dosage of > 0.5 defined daily dose, short-term methotrexate might decrease ischemic stroke risk in RA patients, while hydroxychloroquine and sulfasalazine were neutral.

The effect of anti-rheumatic medications for coronary artery diseases risk in patients with rheumatoid arthritis might be changed over time: A nationwide population-based cohort study

Objectives

To determine whether anti-rheumatic drug usage is associated with risk of coronary artery diseases (CAD) in incident Rheumatoid Arthritis (RA) patients.

Methods

Data were obtained from the Taiwan National Health Insurance Research Database. The study cohort comprised 6260 patients who were newly diagnosed with RA between 2001–2010. The study endpoint was occurrence of CAD according to the ICD-9-CM codes. We used the WHO Defined Daily Dose (DDD) as a tool to assess the drugs exposure. The Cox proportional hazards regression model was used to estimate the hazard ratio (HR) of disease after controlling for demographic and other co-morbidities. When the proportionality assumption is violated, a spline curve of the Scaled Schoenfeld residuals is fitted to demonstrate the estimated effect on CAD over time for drug usage.

Results

Among RA patients, use of celecoxib, and etoricoxib was associated with significantly decreased incidence of CAD. The adjusted HR(95% CI) of CAD for low-dose celecoxib (DDD≦1) and high-dose user were 0.47(0.34, 0.65) and 0.37(0.24, 0.58) during the 4 year follow-up time; however, it became 0.98(0.70, 1.37) and1.29(0.85, 1.95). Adjusted HR(95% CI) of CAD for etoricoxib users remained 0.47(0.26, 0.84).

Conclusions

This study revealed association of decreased CAD risk in RA patients taking 2 different kinds of COX-2i in comparison with nonusers. The effect might be changed over time, after about 4 years.

A semiparametric mixture cure survival model for left-truncated and right-censored data

In follow-up studies, the disease event time can be subject to left truncation and right censoring. Furthermore, medical advancements have made it possible for patients to be cured of certain types of diseases. In this article, we consider a semiparametric mixture cure model for the regression analysis of left-truncated and right-censored data. The model combines a logistic regression for the probability of event occurrence with the class of transformation models for the time of occurrence. We investigate two techniques for estimating model parameters. The first approach is based on martingale estimating equations (EEs). The second approach is based on the conditional likelihood function given truncation variables. The asymptotic properties of both proposed estimators are established. Simulation studies indicate that the conditional maximum-likelihood estimator (cMLE) performs well while the estimator based on EEs is very unstable even though it is shown to be consistent. This is a special and intriguing phenomenon for the EE approach under cure model. We provide insights into this issue and find that the EE approach can be improved significantly by assigning appropriate weights to the censored observations in the EEs. This finding is useful in overcoming the instability of the EE approach in some more complicated situations, where the likelihood approach is not feasible. We illustrate the proposed estimation procedures by analyzing the age at onset of the occiput-wall distance event for patients with ankylosing spondylitis.

Application of xenogeneic anti-canine distemper virus antibodies in treatment of canine distemper puppies

OBJECTIVE

The clinical feasibility of passive immunotherapy has not been demonstrated in dogs naturally infected with canine distemper. In this study, porcine anti-canine distemper virus IgG and F(ab')₂ antibody fragments were used to treat infected puppies.

METHODS

A total of 41 naturally infected puppies (age Äsix months) exhibiting severe respiratory signs, but lacking neurological signs, were enrolled in the study. Twenty-five puppies were treated with a combination of IgG or F(ab')₂ antibody fragments (Group 1) and supportive therapy and 16 puppies received routine supportive care only (Group 2).

RESULTS

The survival rate of dogs in Group 1 (19/25; 76%) was significantly higher than that in Group 2 (5/16; 31·3%) (P<0·05). During the therapy, 8 of the 25 dogs (32%) in Group 1 developed neurological signs versus 12 of the 16 dogs (75%) in Group 2 (P<0·05). Adverse reactions were limited to elevated body temperature in dogs that received IgG antibodies.

CLINICAL SIGNIFICANCE

Porcine anti-canine distemper virus antibodies improved survival in puppies affected with canine distemper with minimal adverse effects. Therefore, this therapy could be considered for treatment of endangered animal species infected with canine distemper virus.

Effects of long term treatment with high doses of odanacatib on bone mass, bone strength, and remodeling/modeling in newly ovariectomized monkeys

The objectives here were to evaluate the effects of odanacatib (ODN) at doses exceeding the clinical exposure on biomechanical properties of lumbar vertebrae (LV), hip and central femur (CF), and compare ODN to alendronate (ALN) on bone remodeling/modeling in ovariectomized (OVX) monkeys. Ten days post-surgery, animals were treated with vehicle (VEH), ODN-L (2mg/kg/day, p.o.), ODN-H (8/4mg/kg/day), or ALN (30μg/kg/week, s.c.) for 20months. An intact group was also included. ODN-L provided systemic exposures of 1.8-fold of clinical exposure. ODN-H started at 20-fold for 5.5months, and then reduced to 7.8-fold of clinical exposure, compared to ALN at approximated clinical exposure. From cross sectional analyses, LV density and peak load in ODN at both doses or ALN were not different from VEH or Intact. However, cortical thickness of femoral neck (FN) and CF in ODN were higher (21-34%, p<0.05) than VEH, due to smaller endocortical (Ec) perimeter of FN (10-11%; p<0.05) and CF (9-12%; ODN-L, p<0.05), and larger CF periosteal (Ps) perimeter (2-12%; ODN-H, p<0.001) versus VEH. ODN groups also showed slightly higher cortical porosity and Ps non-lamellar bone in CF. ODN-H treatment resulted in higher CF peak load (p<0.05) versus VEH. For all bone sites analyzed, a positive, linear relationship (r(2)=0.46-0.69, p<0.0001) of peak load to density or structural parameters was demonstrated. No treatment-related differences in the derived intrinsic strength properties were evidenced as compared between groups. ALN reduced all remodeling surfaces without affecting Ps modeling. Trabecular and intracortical remodeling were reduced in ODN groups, similar to ALN. Ec mineralizing surface in ODN-H trended to be lower than VEH by month 20, but Ec bone formation indices in ODN groups generally were not different from VEH. Ps modeling in ODN groups was significantly higher than other treatment groups. This study overall demonstrated the bone safety profile of ODN and its unique mechanism on cortical bone supporting the clinical application for osteoporosis treatment.

Mitochondrial dysfunction in resveratrol-induced apoptosis in QGY-7701 cells

This study aims to evaluate the cytotoxicity of resveratrol on QGY-7701 cells via a cell viability assay, and determine the cytological alterations and damages that result. Resveratrol was found to inhibit QGY-7701 cell growth and decrease their viability in a remarkably dose-dependent manner. Resveratrol exposure also induced an increase in Caspase-3 activity and a decrease in Bcl-2, which caused an increase in membrane permeability, and the opening of mitochondrial permeability transition pores and mitochondrial depolarization. Cellular ATP is thus exhausted, and apoptosis is induced via the change in mitochondrial membrane permeability and mitochondrial dysfunction.

House dust-mite allergen exposure is associated with serum specific IgE but not with respiratory outcomes

Exposure to house dust has been associated with asthma in adults, and this is commonly interpreted as a direct immunologic response to dust-mite allergens in those who are IgE sensitized to house dust-mite. Mattress house dust-mite concentrations were measured in a population-based sample of 2890 adults aged between 27 and 56 years living in 22 centers in 10 countries. Generalized linear mixed models were employed to explore the association of respiratory symptoms with house dust-mite concentrations, adjusting for individual and household confounders. There was no overall association of respiratory outcomes with measured house dust-mite concentrations, even in those who reported they had symptoms on exposure to dust and those who had physician-diagnosed asthma. However, there was a positive association of high serum specific IgE levels to HDM (>3.5 kUA /l) with mattress house dust-mite concentrations and a negative association of sensitization to cat with increasing house dust-mite concentrations. In conclusion, there was no evidence that respiratory symptoms in adults were associated with exposure to house dust-mite allergen in the mattress, but an association of house mite with strong sensitization was observed.

The impact of joint range of motion limitations on health-related quality of life in patients with haemophilia A: a prospective study

In patients with haemophilia A, repeated occurrences of haemarthrosis and synovitis lead to limitations in range of motion (ROM) of major joints. However, the effect of limitations in joint ROM on health-related quality of life (HRQOL) in these patients has not been studied previously. The aim of this study was to assess the impact of ROM limitations of 10 major joints (bilateral shoulders, elbows, hips, knees and ankles), combined with other possibly influential factors, on HRQOL in patients with haemophilia A. The ROM limitations in 13 movements and pain intensity of the 10 major joints were measured. The socio-demographic and clinical data were recorded. Short-Form 36 was used as the HRQOL measurement. Eighteen patients (mean age: 36.9 years) were included. Hip ROM limitations, knee ROM limitations and hip pain intensity predicted physical functioning scale (P < 0.001; adjusted R2 = 0.553). Shoulder ROM limitations and age predicted role limitation were due to emotional problems scale (P < 0.001; adjusted R2 = 0.373). Elbow ROM limitations and haemophilia severity predicted mental health scale (P = 0.001; adjusted R2 = 0.320). Hip ROM limitations predicted social functioning scale (P = 0.041; adjusted R2 = 0.091). Educational level and elbow ROM limitations predicted vitality scale (P < 0.001; adjusted R2 = 0.416). The ROM limitations of hip, knee, shoulder and elbow could be predictors for HRQOL in patients with haemophilia A. Improving ROM of major joints could be an appropriate treatment strategy to enhance HRQOL in these patients.

Estimated glomerular filtration rate decline is a better risk factor for outcomes of systemic disease-related nephropathy than for outcomes of primary renal diseases

BACKGROUND

Currently, the contribution of kidney function decline in renal and patient outcomes is unclear. There are few data on the associations of different etiologies of estimated glomerular filtration rate (eGFR) decline with outcomes in multidisciplinary care. The purpose of this investigation was to establish whether eGFR decline in patients with disease is an important risk factor for developing end-stage renal disease (ESRD) and death.

METHODS

From December 1, 2001 to December 31, 2011, 5097 adults with chronic kidney disease (CKD) received biochemical tests, physical examinations, a pathological examination, and a comprehensive questionnaire. We used linear regression models and multivariate Cox proportional hazards model to examine the outcome of eGFR decline in renal diseases with different etiologies.

RESULTS

Mean age was 68.1±16.1 (standard deviation, SD) years, and 63.3% patients were male. In the studied cohort, 58.2% of the patients had systemic disease-related nephropathy (SDRN), 29.4% had primary renal diseases (PRDs), and 12.4% had other etiologies. The eGFR decline in SDRN had a significant association with dialysis in the Cox proportional hazards model [crude hazard ratio (HR) = 1.07, 95% confidence interval (CI), 1.04 to 1.10; adjusted HR 1.05, 95% CI, 1.02 to 1.08]. Diabetic nephropathy (DN) had the most severe eGFR decline in CKD stages 3, 4, and 5, and all contributed to the initiation of dialysis and death regardless of whether DN with or without eGFR decline was considered to be the cause. Although hypertensive nephropathy (HN) was related to significant acceleration of eGFR decline, it did not lead to poor outcome. There were still discrepancies between eGFR decline and outcomes in PRDs, hypertensive nephropathy, and lupus nephritis.

CONCLUSIONS

eGFR decline and CKD staging provide an informative guide for physicians to make proper clinical judgments in the treatment of CKD, especially SDRN. Poor control of the underlying systemic disease will thus lead to more rapid progression of SDRN.

The predictive and prognostic significance of pre- and post-treatment topoisomerase IIα in anthracycline-based neoadjuvant chemotherapy for local advanced breast cancer

OBJECTIVE

To investigate the predictive and prognostic value of topoisomerase IIα (Topo IIα, Topo II) expression in the primary tumors and residual tumors of local advanced breast cancer (LABC) patients being treated with anthracycline-based neoadjuvant chemotherapy (NCT).

METHODS

The data from 283 LABC patients who had been treated with anthracycline-based neoadjuvant chemotherapy were collected. The expression of Topo IIα, HER-2 and other biomarkers was determined via immunohistochemical analysis in pre- and post-chemotherapy specimens. The status of pre-treatment biomarkers was correlated with the clinical response determined by the RECIST 1.1 criteria, whereas the post-treatment biomarkers were studied for prognostic value using the Cox model.

RESULTS

By analyzing the complete data from 99 patients, the co-expression of HER-2/Topo IIα was found to be significantly correlated with the clinical response to chemotherapy (Logistic regression P = 0.042). Notably, a 20% alteration in the Topo IIα status during neoadjuvant chemotherapy was found, which could also influence the sensitivity to treatment. With a survival analysis performed in 245 patients with residual tumors after NCT, node metastasis, HER-2 and Ki-67 were independent predictors of patient outcome. However, post-treatment Topo IIα expression demonstrated significant prognostic value in HER-2+ patients (P = 0.002). A relatively lower disease-free survival and overall survival was observed in HER-2+/Topo- patients (log rank P = 0.010 for DFS and P < 0.001 for OS).

CONCLUSION

Topo IIα, together with HER-2, might help to select for patients who could benefit from anthracycline-based neoadjuvant chemotherapy and identify non-complete responders at a higher risk of disease recurrence or death.

Abstract P3-01-05: The Role of Mammographic Calcification in the Neo-adjuvant Therapy of Breast Cancer Imaging Evaluation

Aim: To evaluate the relationship between malignant appearance of mammographic calcification and breast cancer pathological features, and to explore the predictive value of calcification appearances and morphology changes in neo-adjuvant setting.

Methods: 419 patients with operable breast cancer received neo-adjuvant therapy between 2008.2 and 2011.8 in Shanghai Cancer Hospital. Core needle biopsy was conducted before preoperative therapy to determine cancer and achieve pathological features. Mammogram (MG), ultrasound and breast MRI were routinely done prior to therapy and prior to surgical operation. We conducted a detailed analysis of MG images in patients with malignant calcification, recorded the morphology, distribution, range, density, diameter and number of the calcification.

Results: 419 patients enrolled, 108 patients (25.8%) showed malignant calcification in MG, 6 patients missed the first MG before therapy. 214 patients were Luminal A, 95 were Luminal B, 64 were Her2 positive and 46 were triple negative, the pCR rate was 14%, 30.5%, 53%, 43.5% respectively. Patients with malignant calcification have more ER positive (81.5% vs. 71.7%, p = 0.045) and HER2 positive (51.8% vs. 33%, p = 0.001) diseases. The pCR rate was 26% in patients with malignant calcification and 28% in patients without, p = 0.8.

Abstract P6-04-26: Tamoxifen may block estrogen induced secretion of certain cytokines to interrupt tumor associated macrophage infiltration in breast cancer

The role of tumor microenvironment during the initiation and progression of breast cancer is now realized to be of critical importance, both for understanding of the fundamental cancer biology and exploiting relatively new mechanism for breast cancer metastasis. Macrophage is a one of the most common components in the breast cancer microenvironment. Normally, the macrophage in tumor microenvironment is referred to tumor associated macrophage (TAM), which shares some attributes of alternatively activated macrophage. Many pre-clinical and clinical studies demonstrate an inverse correlation between TAM infiltration and patients' prognosis indicating a macrophage supporting role for tumor progression. It is well documented that selective patients with breast cancer can benefit from anti-estrogen therapy. However, the mechanisms involved are still not fully elucidated. Our previous study indicates that highly tumorigenic breast cancer cell line MDA-MB-231 can educate monocyte differentiation into alternatively activated macrophage, while weakly tumorigenic cell line MCF-7 (without estrogen supplementation) can not. In the present study, we explored the effects of estrogen and tamoxifen on the secreting of certain cytokines, which are required for monocyte chemotaxis and differentiation. Breast cancer cell lines with different estrogen receptor status were applied to estimate the level of cytokines (IL4, IL6, M-CSF, GM-CSF, and MCP-1) before and after cultured with 17β-estradiol, tamoxifen or both. We found that weakly invasive breast cancer cell lines (MCF-7, T47D, MDA-MB-468, and SKBR3) generally expressed lower levels of such cytokines compared with highly invasive breast cancer cell lines (MDA-MB-231, MDA-MB-231-BO, MDA-MB-231 HM, Bcap 37, BT549, and Hs578T) at baseline. However, the discrepancies could be compensated partially by exposure to 10nM 17β-estradiol in estrogen receptor (ER) positive cell lines (MCF-7 and T47D). Moreover, the compensation was substantially blocked by 2μM tamoxifen. On the contrary, tamoxifen, alone, didn't affect the secretion of such cytokines mentioned above in vitro. Based on these findings, we tentatively concluded that some patients with ER positive breast cancers benefiting from anti-estrogen therapy may partially attributes to blocking monocyte differentiation into TAM, which destroyed the tumor microenvironment. These findings suggest the future possibility of using TAM as a novel therapeutic target in patients with anti-estrogen resistance and primary triple-negative breast cancers (TNBC) with no effectively therapeutic measures nowadays, which are defined by lack of estrogen receptor, progesterone receptor and ERBB2 gene amplification, representing approximately 16% of all breast cancers.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-04-26.

A fractal dimensional approach to successful evaluation of apical healing

AIM

To evaluate whether the initial healing of apical radiolucencies 1 year after root canal treatment could be quantitatively identified by the change in fractal dimension (FD) values for the eventually completely healed cases.

METHODOLOGY

Twenty-six patients with successful root canal treatment were recruited. All teeth were associated with complete healing either before or at 1 year following treatment (six of 26) or still undergoing healing at 1 year after treatment but completely healed thereafter (20 of 26). Two radiographs were selected for the same patient, one taken before treatment and the other taken 1 year after treatment. Eight regions of interests (ROIs) were selected from each radiograph, two as the experimental group located close to the infected root apex, two as the control group in the healthy bone and the other four in the healthy bone ensuring the image quality.

RESULTS

Based on the FD values of the four ROIs in the healthy bone, the two radiographs were confirmed to have been taken with similar projection angles and exposure. The FD values were shown to significantly increase (P = 0.006) and decrease (P = 0.000) around the root apex and the neighbouring region of the apical lesion, respectively.

CONCLUSION

Changes in fractal dimension values may serve as a necessary condition to quantitatively indicate the initial healing status 1 year after root canal treatment.

Bone healing response to a synthetic calcium sulfate/β-tricalcium phosphate graft material in a sheep vertebral body defect model

The introduction of a material able to promote osteogenesis and remodelling activity in a clinically relevant time frame in vertebroplasty and kyphoplasty procedures may have patient benefit. We report the in-vivo performance of a biphasic synthetic bone graft material (Genex Paste, Biocomposites, UK) [test material], composed of calcium sulfate and β-tricalcium phosphate, implanted into a sheep vertebral defect model. Cavities drilled into 4 adjacent vertebrae (L2 to L5) of 24 skeletally mature sheep were; (1) filled with the test material; (2) filled with commercially available polymethylmethacrylate [PMMA] cement; (3) remained empty [sham]. Analysis was performed immediately after implantation and at 8, 16, and 36 weeks post implantation. Sites were evaluated for bone growth with microCT analysis, histological examination, and mechanical testing under compression. The test material exhibited an improved tissue response over the PMMA, indicating a superior biological tolerance. MicroCT and histology indicated marked osteoregenerative capacity of the test material when compared with sham and the PMMA. The percentage of new bone formation was higher for the test material than sham at 16 and 36 weeks post implantation, with bone regeneration almost complete at 36 weeks in this group. Resorption of test material and the integration into new bone tissue were demonstrated. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.

Respiratory health and endotoxin: associations and modification by CD14/-260 genotype

Exposure to endotoxin has been associated with increased respiratory symptoms and decrements in lung function in occupational settings but little is known about the health effects of domestic exposure in adults. Here, we describe the association of respiratory disease, immunoglobulin (Ig)E sensitisation, bronchial reactivity and lung function with mattress endotoxin levels in adults, and determine whether these associations are modified by polymorphisms in CD14. Endotoxin levels in mattress dust from a population-based sample of 972 adults were measured. Associations were examined using generalised linear mixed models, adjusting for individual and household confounders. Effect modification of these associations by CD14/-260 (rs2569190) was assessed. Mattress endotoxin levels varied from 0.1 to 402.6 EU · mg(-1). Although there was no overall association of lung function with endotoxin exposure, there was evidence that the association of forced expiratory volume in 1 s and forced vital capacity with endotoxin was modified by CD14/-260 genotype (p-value for interaction 0.005 and 0.013, respectively). There was no evidence that symptoms, IgE sensitisation or bronchial reactivity were associated with mattress endotoxin levels. In this large epidemiological study of adults, there was no evidence that mattress endotoxin level was associated with respiratory symptoms or IgE sensitisation but the association of lung function with endotoxin levels may be modified by CD14 genotype.

A two-stage estimation in the Clayton-Oakes model with marginal linear transformation models for multivariate failure time data

This paper considers the analysis of multivariate survival data where the marginal distributions are specified by semiparametric transformation models, a general class including the Cox model and the proportional odds model as special cases. First, consideration is given to the situation where the joint distribution of all failure times within the same cluster is specified by the Clayton-Oakes model (Clayton, Biometrika 65:141-151, l978; Oakes, J R Stat Soc B 44:412-422, 1982). A two-stage estimation procedure is adopted by first estimating the marginal parameters under the independence working assumption, and then the association parameter is estimated from the maximization of the full likelihood function with the estimators of the marginal parameters plugged in. The asymptotic properties of all estimators in the semiparametric model are derived. For the second situation, the third and higher order dependency structures are left unspecified, and interest focuses on the pairwise correlation between any two failure times. Thus, the pairwise association estimate can be obtained in the second stage by maximizing the pairwise likelihood function. Large sample properties for the pairwise association are also derived. Simulation studies show that the proposed approach is appropriate for practical use. To illustrate, a subset of the data from the Diabetic Retinopathy Study is used.

Acute disseminated encephalomyelitis that meets modified McDonald criteria for dissemination in space is associated with a high probability of conversion to multiple sclerosis in Taiwanese patients

BACKGROUND

Patients with acute disseminated encephalomyelitis (ADEM) may relapse and some may ultimately convert to multiple sclerosis (MS); however, no criteria that can predict MS conversion are available to date. Our aim was to describe the clinical and magnetic resonance imaging (MRI) features of patients with an initial ADEM attack and evaluate which MRI criteria can predict conversion to MS.

METHODS

We retrospectively reviewed the records of 36 patients diagnosed with ADEM. We determined clinical signs/symptoms, examined the cerebrospinal fluid (CSF), and performed brain MRI scans and compared the findings between patients who did and did not convert to MS.

RESULTS

Clinical signs/symptoms, and CSF analysis show no significant difference between the two groups. The rate of conversion to MS from ADEM in Taiwanese patients is low (11%) after a mean follow-up period of 28.36 months. Modified McDonald criteria were fulfilled in 19/36 patients: 21% (4/19) of those patients developed MS according to Poser criteria subsequently. Of the other patients (17/36) who did not fulfill these criteria, none converted to MS. (log rank test; P=0.027).

CONCLUSIONS

It is difficult to predict from initial clinical presentations to address which patients with ADEM will convert to MS. Patients with ADEM whose brain MRI findings met the modified McDonald criteria may have clinically isolated syndrome because they have a significantly higher probability of conversion to MS. In contrast, patients whose brain MRI findings did not meeting these criteria may be considered as having classic ADEM because they have a lower probability of conversion to MS.

Methylprednisolone reduces the rates of postextubation stridor and reintubation associated with attenuated cytokine responses in critically ill patients

BACKGROUND

Treatment with corticosteroids can reduce the incidence of postextubation stridor (PES) and reintubation in critically ill adult patients, but the mechanisms remain unknown.

METHODS

A randomized, controlled clinical trial was conducted in an adult medical and surgical Intensive Care Unit (ICU) of a teaching hospital. Seventy-one patients who had a cuff leak percentage <24% of tidal volume received either a bolus injection of methylprednisolone at 40 mg (treated group, n=38) or normal saline (placebo group, n=33) 4 h prior to a planned extubation. The cuff leak percentage was re-assessed 1 h and 4 h post-injection. Eighty patients who had a cuff leak percentage ≥ 24% served as a control group. Plasma concentrations of multiple cytokines and C-reactive protein (CRP) were measured at baseline, 4 h and 24 h after the intervention.

RESULTS

The incidences of PES (15.8% vs. 39.4%, P<0.05) and reintubation rate (7.9% vs. 30.3%, P<0.05) were lower in the treated group compared to the placebo group. The plasma concentrations of IL-4 and IL-10 increased while the levels of IL-6 and IL-8 decreased at 24 h in the treated group compared to the placebo group. No difference in CRP levels was observed between the treated and placebo groups.

CONCLUSION

A single injection of methylprednisolone at the dose used 4 h prior to planned extubation effectively reduced the incidence of PES and the reintubation rate. These beneficial effects were associated with the up-regulation of IL-4 and IL-10 and the down-regulation of IL-6 and IL-8 in the critically ill adult patients.