Propensity score matching for estimating a marginal hazard ratio.

Propensity score matching is commonly used to draw causal inference from observational survival data. However, its asymptotic properties have yet to be established, and variance estimation is still open to debate. We derive the statistical properties of the propensity score matching estimator of the marginal causal hazard ratio based on matching with replacement and a fixed number of matches. We also propose a double-resampling technique for variance estimation that takes into account the uncertainty due to propensity score estimation prior to matching.

PIGMENT EPITHELIAL DETACHMENT THICKNESS AND VARIABILITY AFFECTS VISUAL OUTCOMES IN PATIENTS WITH NEOVASCULAR AGE-RELATED MACULAR DEGENERATION.

PURPOSE: To evaluate the impact of pigment epithelial detachment (PED) thickness (i.e., height) and thickness variability on best-corrected visual acuity outcomes in patients with neovascular age-related macular degeneration in the Phase 3 HAWK and HARRIER trials. METHODS: Optical coherence tomography images from the pooled brolucizumab 6 mg and aflibercept 2 mg arms were analyzed for the maximum PED thickness across the macula at baseline through to week 96. Best-corrected visual acuity outcomes were compared in patients with different PED thickness and variability cut-off thresholds. RESULTS: Greater PED thickness at baseline or at week 12 was associated with lower mean best-corrected visual acuity gain from baseline to week 96 (baseline PED ≥200 µ m: +4.6 letters; <200 µ m: +7.0 letters; week 12 PED ≥100 µ m: +5.6 letters; <100 µ m: +6.6 letters). Eyes with the largest PED thickness variability from week 12 through week 96 gained fewer letters from baseline at week 96 (≥33 µ m: +3.3 letters; <9 µ m: +6.2 letters). Furthermore, increased PED thickness at week 48 was associated with higher prevalence of intraretinal and subretinal fluid. CONCLUSION: In this treatment-agnostic analysis, greater PED thickness and PED thickness variability were associated with poorer visual outcomes in patients with neovascular age-related macular degeneration and greater neovascular activity.

Thrombopoietin receptor agonists for refractory thrombocytopenia in patients after autologous hematopoietic stem cell transplantation.

OBJECTIVE: Autologous hematopoietic stem cell (ASC) transplantation (ASCT) is an effective treatment method for patients with hematological disorders and malignant diseases. The patient's ASCs are harvested prior to radiotherapy/chemotherapy, cryopreserved and then transfused back after the high-dose radiotherapy/chemotherapy conditioning treatment. Since some patients develop thrombocytopenia after receiving ASCT, it is difficult for them to bear simultaneously the management of their original disease and thrombocytopenia. The present study aimed to evaluate the efficacy and safety of thrombocytopenia therapy with thrombopoietin receptor agonists (TPORAs) after ASCT. METHODS: We retrospectively analyzed the clinical safety and efficacy of TPORA treatment for the enrolled 20 patients who developed thrombocytopenia after ASCT. The measured parameters were prolonged isolated thrombocytopenia (PIT), secondary failure of platelet recovery (SFPR) and other calculated response index. Patients with platelet count (PC) ≤ 50×109/L were treated with TPORA, namely with either eltrombopag (Elt), hetrombopag (Het), or avatrobopag (Ava). RESULTS: The group of 20 patients, who received TPORA administration for their thrombocytopenia after ASCT, had a median age of 50 years (ranging between 17 and 60 years). The median administration time of TPORA application was 48 days (ranging from 7 to 451 days); an overall response rate (ORR) was 85% with no response in 15% of patients, while with complete response (CR) in 70% of patients and partial response (PR) in 15% of patients. The median platelet count was 19 × 109/L before TPORA treatment and increased to 87×109)/L after the treatment. The TPORA treatment was safe as only 4 patients (20%) displayed a mild transaminase elevation. No other reported side effects occurred, such as thrombosis, joint pain, diarrhea, and myelofibrosis. It was demonstrated that the short response time to TPORA treatment correlated to the fast platelet recovery, when the number of megakaryocytes in the bone marrow smear exceeded 35/4.5 cm2 under a low magnification of 100 times (p = 0.015). CONCLUSION: TPORA therapy for thrombocytopenia occurring after the radiotherapy/ chemotherapy-conditioned ASCT was well tolerated and effective for platelets recovery.

Clinical Characteristics of Elderly Patients with Diffuse Large B-cell Lymphoma and the Risk Factors Affecting Cardiotoxicity of Anthracycline.

Objective: The objective of this study was to describe the clinical characteristics of elderly patients diagnosed with diffuse large B-cell lymphoma (DLBCL) and to identify the risk factors associated with anthracycline-related cardiotoxicity in this patient population. Methods: A retrospective analysis was conducted on a cohort of 170 elderly patients (≥65 years old) with DLBCL who were treated at our hospital between January 2015 and December 2020. Clinical characteristics and laboratory parameters were collected and analyzed. All patients were followed up until June 2021 to record survival, short-term efficacy, recurrence, and anthracycline-related cardiotoxicity in those who received chemotherapy. Results: Among the 170 elderly patients with DLBCL, the median progression-free survival (PFS) and median overall survival (OS) were 47 and 91 months, respectively. The 3-year PFS and OS rates were 54.1% and 70.1%, while the 5-year PFS and OS rates were 47.7% and 64.1%, respectively. The objective remission rate (ORR) was 78.83%, with a complete remission rate of 44.12% and a partial remission rate of 34.71%. Out of 143 patients who received anthracycline treatment, 46 patients experienced cardiotoxicity. Multivariate logistic regression analysis indicated that non-liposomal anthracycline use, no use of dextrexacin, and diabetes mellitus with complications were significant risk factors affecting cardiotoxicity (P < .05). Conclusions: The study showed that elderly patients with DLBCL had a high incidence of cardiotoxicity when treated with anthracycline. The results emphasize the importance of considering clinical characteristics and auxiliary examinations to prevent cardiotoxicity associated with anthracycline use.

Benefits of Dynamic Nomogram Models for Elderly Diffuse Large B-Cell Lymphoma Patients' Early Death Prediction and Clinical Application.

Background: Diffuse large B-cell lymphoma (DLBCL) is an aggressive malignancy, and about 60% of the patients are diagnosed in their elderly age (≥65 years old). However, little is known about the early mortality and risk factors related to elderly patients with DLBCL. Methodology. From 2000 to 2019, elderly patients diagnosed with DLBCL in the Surveillance, Epidemiology, and End Result (SEER) database were involved in this research and served as test cohort. Moreover, elderly DLBCL patients from Peking University Third Hospital were used for external validation cohort. Risk factors were identified by univariate and multivariate logistic regression analyses. Nomogram models were constructed based on significance risk factors to predict the overall and cancer-specific early death. Besides that, the predictive value of the models was validated by receiver operating characteristic (ROC) analysis. Calibration plots were used to evaluate the calibrating ability. Clinical benefits of nomogram were evaluated by decision curve analysis (DCA). Results: 15242 elderly DLBCL patients obtained from the SEER database and 152 patients from Peking University Third Hospital were enrolled in this research. In the SEER database, 36.6% (5584/15242) of the patients had early death and 30.7% (4680/15242) of them were cancer-specific early death. Marital status, Ann Arbor stage, surgical treatment, radiotherapy, and chemotherapy were significant risk factors for overall and cancer-specific early death of elderly DLBCL patients. Nomograms were constructed according to these risk factors. Then, ROC analysis showed that the AUC of OS was 0.764 (0.756~0.772), and CSS was 0.742 (0.733~0.751). In the validation group, the AUC of OS was 0.767 (0.689~0.846) and CSS was 0.742 (0.743~0.83). Conclusion: The calibration plots and DCA analysis revealed that the nomograms were good at early death prediction and clinical application. Predictive dynamic nomogram models for elderly DLBCL patients were established and validated, which might play an essential role in helping physicians enact better treatment strategies.

IMPACT OF RETINAL FLUID-FREE MONTHS ON OUTCOMES IN NEOVASCULAR AGE-RELATED MACULAR DEGENERATION: A Treatment Agnostic Analysis of the HAWK and HARRIER Studies.

PURPOSE: To assess the effect of the total number of fluid-free months after loading on visual and anatomical outcomes in neovascular age-related macular degeneration patients receiving anti-vascular endothelial growth factor therapy. METHODS: This post hoc analysis pooled patient-level data from the brolucizumab 6 mg (n = 718) and aflibercept 2 mg (n = 715) arms of the HAWK and HARRIER randomized clinical trials. Based on data from Weeks 12 to 96, patients were assigned to one of five categories based on fluid-free visits (FFVs; the total number of monthly visits at which they were observed to be without retinal fluid). Three definitions of "fluid-free" were explored based on the location of the fluid observed. RESULTS: Patients allocated to Categories 4 (15-21 FFV) and 5 (22 FFV, always dry) consistently had the best visual and anatomical outcomes at Week 96, whereas patients allocated to Categories 1 (0 FFV, never dry) and 2 (1-7 FFV) consistently had the worst visual and anatomical outcomes. Variability in retinal thickness over time was lowest in Categories 4 and 5. CONCLUSION: Absence of retinal fluid at more visits after loading has a positive association with visual and anatomic outcomes in neovascular age-related macular degeneration patients, regardless of fluid type.

Three new sesquiterpenes from Ixeris sonchifolia.

Two new guaiacene-type sesquiterpenes 13α-dihydroixerin acid, ixerin acid and one new secoguaiacene-type sesquiterpene secoixerin Z, along with four known compounds, were separated from ethanol extract of Ixeris sonchifolia. The structures were determined based on the detailed spectroscopic and physicochemical methods. The cytotoxic activity of the isolates was tested against A549 cells. Among them, compound 3 exhibited potent cytotoxicity against A549 cells with the IC50 of 5.6 ± 0.9 µM.

Spectral Estimation Using Multitaper Whittle Methods with a Lasso Penalty.

Spectral estimation provides key insights into the frequency domain characteristics of a time series. Naive non-parametric estimates of the spectral density, such as the periodogram, are inconsistent, and the more advanced lag window or multitaper estimators are often still too noisy. We propose an L 1 penalized quasi-likelihood Whittle framework based on multitaper spectral estimates which performs semiparametric spectral estimation for regularly sampled univariate stationary time series. Our new approach circumvents the problematic Gaussianity assumption required by least square approaches and achieves sparsity for a wide variety of basis functions. We present an alternating direction method of multipliers (ADMM) algorithm to efficiently solve the optimization problem, and develop universal threshold and generalized information criterion (GIC) strategies for efficient tuning parameter selection that outperform cross-validation methods. Theoretically, a fast convergence rate for the proposed spectral estimator is established. We demonstrate the utility of our methodology on simulated series and to the spectral analysis of electroencephalogram (EEG) data.

Simultaneous determination of paeonilactone A and paeonilactone B in rat plasma after oral administration of albiflorin by UPLC/TOF/MS following picolinoyl derivatization.

A new highly sensitive analytical method was developed to investigate the in vivo metabolism of albiflorin, one of the most principal components in traditional Chinese medicine. After hydrolyzation with sulfatase, the main metabolites paeonilactone A and paeonilactone B of paeoniflorin in rat plasma were successfully detected for the first time by liquid chromatography mass spectrometry following picolinoyl derivatization. Borneol was used as the internal standard compound to quantify paeonilactone A and paeonilactone B in rat plasma. Paeonilactone A and paeonilactone B show different pharmacokinetic behaviors. The maximum plasma concentration of paeonilactone A reached 36.4±5.6ng/mL at about 8h after oral administration of albiflorin at a dose of 5mg/kg, while the maximum plasma concentration of paeonilactone B reached 12.4±3.4ng/mL at about 2h. The total metabolic pathway of albiflorin in rats was proposed. Albiflorin was found to be metabolized to the sulfate of paeonilactone A and paeonilactone B which may be responsible for the biological effect of albiflorin. The new analytical method may help to elucidate the clinical efficacy of traditional Chinese formula containing albiflorin.

New analytical method for determination of epimer metabolites in rat plasma after oral administration of Paeoniflorin by UPLC-TOF-MS following picolinoyl derivatization.

A highly sensitive analytical method was developed to study the in vivo metabolism of paeoniflorin, one of the most principal components in traditional Chinese medicine. After hydrolyzation with sulfatase, the epimer metabolites 7S-paeonimetabolin I and 7R-paeonimetabolin I of paeoniflorin in rat plasma were successfully detected and well separated by LC-MS following picolinoyl derivatization for the first time. Borneol was used as the internal standard to quantify 7S-paeonimetabolin I and 7R-paeonimetabolin I in rat plasma. 7S-paeonimetabolin I and 7R-paeonimetabolin I show similar but different pharmacokinetic behavior. 7S-paeonimetabolin I reached the maximum mean plasma concentration of 45.7±4.6ng/mL at about 1.5h after oral administration of paeoniflorin at a dose of 5mg/kg, while 7R-paeonimetabolin I reached the maximum mean plasma concentration of 39.2±3.5ng/mL at about 1.5h. The full metabolic pathway of paeoniflorin in rats was proposed. The monoterpene compound paeoniflorin was found to be metabolized to the sulfate of 7S-paeonimetabolin I and 7R-paeonimetabolin I in vivo which maybe responsible for the pharmacological effect of paeoniflorin.

Determination of the metabolic profile of gentianine after oral administration to rats by high performance liquid chromatography/electrospray ionization-trap mass spectrometry.

We investigated the metabolic fate of gentianine after oral administration to Wistar rats for the first time. Liquid chromatography/ion trap mass spectrometry detected four metabolites secogentianoxide, gentiandiol, gentianepoxide and gentianoxide in rat plasma together with the original compound gentianine. The structures of the metabolites were identified by comparing the retention times, as well as MS (mass) and MS/MS (tandem mass) spectra with those of authentic compounds, which were synthesized from gentianine or isolated from the urine. Three of the metabolites, secogentianoxide, gentianepoxide and gentianoxide, are novel compounds. The major in vivo metabolic processes associated with gentianine include N-oxide, epoxidation, dihydroxylation of double bond and hydrolysis of lactone. Gentianine together with the metabolites in plasma were quantified using gentianone as the internal standard. The mean C(max) of G0, G1, G2 and G3 are 425.76, 287.56, 188.45 and 85.05 ng/mL, respectively. The mean T(max) of G0, G1, G2 and G3 are 1.16, 3.87, 6.23 and 4.28 h, respectively. The mean T(1/2) of G0, G1, G2 and G3 are 5.23, 12.34, 7.78 and 5.64 h, respectively. A comprehensive metabolic pathway was proposed. The new metabolites may shed light on clinical efficacy of gentianine.

New analytical method for the study of metabolism of swertiamarin in rats after oral administration by UPLC-TOF-MS following DNPH derivatization.

The metabolism of swertiamarin in vivo was studied by LC-MS following 2,4-dinitrophenylhydrazine derivatization. The ionization efficiency of the main metabolite erythrocentaurin was greatly enhanced by the new analytical method developed, and erythrocentaurin was successfully detected for the first time in rat plasma after oral administration of swertiamarin. Methyl 4-formylbenzoate was used as the internal standard to quantify erythrocentaurin in rat plasma in negative mode by UPLC-TOF-MS, and it was found that erythrocentaurin reached the maximum mean plasma concentration of 425.8 ± 127.6 ng/mL at about 2 h after oral administration of swertiamarin at a dose of 200 mg/kg. A metabolic pathway of swertiamarin to erythrocentaurin was proposed. Swertiamarin is first hydrolyzed by bacterial ß-glucusidase to give the aglycone, which is readily converted to erythrocentaurin. The monoterpene compound swertiamarin was found to be metabolized to dihydroisocoumarin and alkaloid compounds in vivo, which may be responsible for the pharmacological effect of swertiamarin. The results may shed light on the clinical efficacy of swertiamarin and the new analytical method may assist in studies for the metabolism of other natural iridoids and secoiridoids in vivo.

Two main metabolites of gentiopicroside detected in rat plasma by LC-TOF-MS following 2,4-dinitrophenylhydrazine derivatization.

The metabolism of gentiopicroside in vivo was studied by LC/MS following 2,4-dinitrophenylhydrazine derivatization for the first time. The ionization efficiency of the major metabolites erythrocentaurin and gentiopicral were greatly enhanced by the new analytical method developed, and they were successfully detected in rat plasma after oral administration of gentiopicroside. Methyl 4-formylbenzoate was used as the internal standard to quantify erythrocentaurin and gentiopicral in rat plasma in negative mode by UPLC-TOF-MS. It was found that erythrocentaurin reached the maximum plasma concentration of 625.2±246.3 ng/mL at about 2 h and gentiopicral reached the maximum plasma concentration of 157.6±86.6 ng/mL at about 4 h after oral administration of gentiopicroside at a dose of 200 mg/kg. The metabolic pathway of gentiopicroside to erythrocentaurin and gentiopicral was proposed. The monoterpene compound gentiopicroside was found to be metabolized to dihydroisocoumarin in vivo which may be responsible for the pharmacological effect of gentiopicroside. The results may shed light on clinical efficacy of gentiopicroside and the new analytical method developed may assist in studies for the metabolism of other natural iridoids and secoiridoids in vivo.

Highly sensitive determination of new metabolite in rat plasma after oral administration of swertiamarin by liquid chromatography/time of flight mass spectrometry following picolinoyl derivatization.

The metabolism of swertiamarin (STM) in vivo was studied by LC/MS following picolinoyl derivatization. Incubation of erythrocentaurin (ECR), one of the main in vitro metabolites of STM by intestinal bacteria, with liver microsome indicated that STM may be metabolized to the final metabolite 3,4-dihydro-5-(hydroxymethyl) isochroman-1-one (HMIO) in vivo. After hydrolyzation with sulfatase, HMIO was successfully detected in rat plasma after oral administration of STM by LC/MS following picolinoyl derivatization. 4-Methoxyphenyl methanol was used as the internal standard to quantify HMIO in rat plasma. The full metabolic pathway of STM in rats is proposed. STM is first hydrolyzed by bacterial ß-glucusidase to give aglycone, which is readily converted to ECR and nitrogen-containing metabolite. ECR is further reduced to HMIO by both liver and intestinal bacteria and HMIO is finally converted to the new sulfate conjugate metabolite. The monoterpene compound STM was found to be metabolized to dihydroisocoumarin and alkaloid compounds in vivo, which may be responsible for the pharmacological effect of STM. The results may shed light on clinical efficacy of STM and the new analytical method developed may assist in studies of the metabolism of other natural iridoids and secoiridoids in vivo.

Qualitative and quantitative analysis of Swertia herbs by high performance liquid chromatography-diode array detector-mass spectrometry (HPLC-DAD-MS).

We evaluated the composition of Swertia herbs using high performance liquid chromatography-diode array detector-mass spectrometry (HPLC-DAD-MS). Eleven peaks of 6 species were unequivocally identified by comparing their retention times, UV spectra, on-line electrospray ionization mass (ESI-MS) spectra, and collision-induced dissociation mass spectrometry/mass spectrometry (CID-MS/MS) data with those of authentic compounds. We adopted wavelengths of 254 nm, 340 nm and 230 nm to simultaneously determine these 11 compounds. By comparing the overall DAD and total ion current (TIC) profiles of various samples, the 6 species were differentiated in terms of the occurrence and/or relative concentrations of the eleven compounds. Our novel validated HPLC-DAD-MS method not only facilitates quality control and identification of Swertia herbs, but is also applicable to systematic investigations of the distribution of secoiridoids, flavonoids, and xanthones in the genus Swertia.

Prolidase isoenzymes in the rat: their organ distribution, developmental change and specific inhibitors.

Lack of prolidase I (PD I) leads to prolidase deficiency, a disease characterized by intractable skin lesions, recurrent respiratory infections, and mental retardation. The present study was undertaken to characterize and determine the physiologic roles of different prolidase isoenzymes. Two isoforms of prolidase were isolated from rat kidney. PD I showed higher activity against seryl-proline and alanyl-proline, whereas PD II was active especially against methionyl-proline. PD I was highly concentrated in the small intestine and kidney, whereas PD II was shown not to vary in the organs examined. Expression of PD I and PD II in the small intestine were maximal within 1 wk of birth, and then rapidly declined. The changes of prolidase in the kidney and heart were found to differ slightly. N-benzyloxycarbonyl-l-proline and captopril inhibited PD I dose-dependently, but showed no inhibition of PD II at low concentrations. NiCl2 inhibited PD II much more effectively than PD I. Our findings suggest that PD I functions by way of an intestinal peptide carrier, which may also be regulated by the uptake of various iminodipeptides. Similarly, age-related alterations of prolidase isoenzymes suggest that intestinal PD II also participates in absorption of proline and other amino acids early in life.

Effect of five triterpenoid compounds from the buds of Aralia elata on stimulus-induced superoxide generation, tyrosyl phosphorylation and translocation of cytosolic compounds to the cell membrane in human neutrophils.

The buds of Aralia elata (Miq.) Seem (Japanese angelica tree) have long been used as a tonic, antiarthritic and antidiabetic agent in China and Japan. We have isolated five triterpenoids, congmuyanosides A, C, D, echinocystic acid and 3-O-[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl]-hederagenin from the buds of Aralia elata , and investigated their effects on stimulus-induced superoxide generation in human neutrophils. Congmuyanoside A, echinocystic acid and 3-O-[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl]-hederagenin suppressed the superoxide generation induced by N-formyl-methionyl-leucyl-phenylalanine (fMLP) in a concentration-dependent manner. Congmuyanosides C, D and echinocystic acid significantly suppressed the superoxide generation induced by phorbol 12-myristate 13-acetate (PMA) and arachidonic acid (AA). The compounds also suppressed fMLP- and AA-induced tyrosyl or PMA-induced serine/threonine phosphorylation and translocation of cytosolic compounds, p47 (phox), p67 (phox) and Rac to the cell membrane.