Antioksidacijska i protuupalna aktivnost paraoksonaze i lipidni pokazatelji u svinja nakon splenektomije i autotransplantacije slezene.

The objective of this study was to investigate serum PON1 activity and lipid and lipoprotein status after total splenectomy and autologous spleen transplantation in pigs, in order to assess the effect of surgical stress and trauma on PON1 activity and lipid metabolism. Nineteen piglets used in the experiment were randomly divided into three groups: sham-operation with spleens intact (n = 6), total splenectomy (n = 6), and splenic autotransplantation (n = 7) with small fragments of the spleen autotransplanted into the greater omentum. The blood samples were taken just before surgery and on the 1st, 5th, 12th, 26th and 40th days postoperatively. PON1 activity, total cholesterol and HDL-C were assayed in the sera. PON1 activity was significantly decreased postoperatively in splenectomized pigs (on days 5, 12 and 40) and in autotransplantated pigs (on days 5, 12, 26 and 40) while there were no PON1 changes in the sham-operated. In sham-operated pigs, total cholesterol was significantly decreased only on the 12th day postoperatively, while HDL-C was significantly decreased postoperatively on the 1st, 5th, 12th, 26th and 40th days with the minimum value on the 12th day. In splenectomized pigs total cholesterol was significantly decreased on the 5th, 12th, 26th and 40th days postoperatively, while HDL-C was decreased as well on the 1st, 5th, 12th and 40th days and both were the lowest on the 12th day. In pigs with autologous splenic transplants, total cholesterol was significantly decreased on the 12th, 26th and 40th days, while there was no difference in HDL-C. The results demonstrated decreased PON1 activity and alterations in the concentrations of total cholesterol and HDL-C after surgery due to surgical trauma and post-surgical inflammatory response.Cilj je ovoga rada bio istražiti aktivnost PON1 te lipidni status u serumu svinja nakon splenektomije i autotransplantacije slezene u namjeri da se procijeni učinak stresa i traume na aktivnost PON1 i metabolizam lipida u tijeku kirurškoga zahvata. U istraživanje je bilo uključeno 19 praščića koji su nasumično bili raspodijeljeni u tri skupine: (1) laparoskopija s intaktnom slezenom (n = 6), (2) splenektomija (n = 6) i autotransplantacija slezene (n = 7). Uzorci krvi uzimani su neposredno prije kirurškoga zahvata, te 1., 5., 12., 26. i 40. dan nakon operacije. U serumu je određena aktivnost PON1, te koncentracija ukupnoga kolesterola i HDL-kolesterola. Aktivnost PON1 bila je značajno snižena postoperativno u splenektomiranih (5., 12. i 40. dan) i autotransplantiranih životinja (5., 12., 26. i 40. dan), dok u skupini u kojoj je učinjena laparoskopija nije bilo značajnih razlika u aktivnosti PON1 nakon operacije. U skupini podvrgnutoj laparoskopiji, ukupan kolesterol bio je značajno manji samo 12. dan nakon operacije, dok je HDL-C bio manji 1., 5., 12., 26. i 40. dan postoperativno s najmanjom vrijednošću 12. dan. U splenektomirane prasadi, ukupan kolesterol bio je značajno manji 5., 12., 26. i 40. dan postoperativno, a HDL-C je bio manji 5., 12. i 40. dan nakon operacije. U prasadi kojoj je autotransplantirana slezena, ukupni je kolesterol bio značajno manji 12., 26. i 40. dan nakon operacije, dok se koncentracija HDL-C nije značajno razlikovala prije i nakon operacije. Rezultati pokazuju smanjenu aktivnost PON1 i promjene koncentracija ukupnog kolesterola i HDL-C uzrokovane kirurškom traumom i upalnim odgovorom nakon operacije

Oksidacijski stres u mliječnih krava – povezanost aktivnosti paraoksonaze u serumu i povećanja jetre

Association of serum paraoxonase (PON) activity and hepatomegaly in dairy cows as well as the relation between PON activity and HDL cholesterol concentration were studied considering the role of oxidative stress in reproductive and metabolic disorders in dairy caws. A significantly lower PON activity (P<0.01) was found in cows with hepatomegaly compared to clinically healthy cows. Concentrations of serum glucose, triglyceride and cholesterol were also markedly reduced in cows with hepatomegaly (P<0.001, P<0.001 and P<0.05, respectively), whereas the serum HDL cholesterol concentration showed no significant change. Paraoxonase/ HDL-cholesterol ratio in hepatomegaly was significantly lower (P<0.05) as well. As part of antioxidative defence against lipid peroxidation, lower PON activity contributes to an increased risk of oxidative stress in cows with hepatomegaly.Uzimajući u obzir ulogu oksidacijskoga stresa u reprodukcijskim i metaboličkim poremećajima, istražena je aktivnost paraoksonaze (PON) u serumu mliječnih krava s povećanom jetrom te odnos aktivnosti PON i koncentracije HDL-kolesterola. Utvrđena je značajno manja aktivnost PON u skupini krava s povećanom jetrom u usporedbi s kontrolnom skupinom. Koncentracije glukoze (P<0,001), triglicerida (P<0,001) i kolesterola (P<0,05) bile su također značajno manje u skupini krava s povećanom jetrom nego u skupini zdravih krava. Koncentracija HDL-kolesterola nije se statistički razlikovala između skupina, dok je omjer PON/HDL-kolesterol bio značajno manji (P<0.05) u krava s povećanom jetrom. Smatrajući PON kao dio antioksidacijskoga sustava u sprečavanju peroksidacije lipida, njena niža aktivnost može doprinijeti povećanom riziku od oksidacijskoga stresa u mliječnih krava s povećanom jetrom

Dealing with Missing Responses in Cognitive Diagnostic Modeling

Missing data are a common problem in educational assessment settings. In the implementation of cognitive diagnostic models (CDMs), the presence and/or inappropriate treatment of missingness may yield biased parameter estimates and diagnostic information. Using simulated data, this study evaluates ten approaches for handling missing data in a commonly applied CDM (the deterministic inputs, noisy “and” gate (DINA) model): treating missing data as incorrect (IN), person mean (PM) imputation, item mean (IM) imputation, two-way (TW) imputation, response function (RF) imputation, logistic regression (LR), expectation-maximization (EM) imputation, full information maximum likelihood (FIML) estimation, predictive mean matching (PMM), and random imputation (RI). Specifically, the current study investigates how the estimation accuracy of item parameters and examinees’ attribute profiles from DINA are impacted by the presence of missing data and the selection of missing data methods across conditions. While no single method was found to be superior to other methods across all conditions, the results suggest the use of FIML, PMM, LR, and EM in recovering item parameters. The selected methods, except for PM, performed similarly across conditions regarding attribute classification accuracy. Recommendations for the treatment of missing responses for CDMs are provided. Limitations and future directions are discussed

Developing a Facilitators Scale in the Context of Travel: ReTRIP

Objective: To develop a scale for measuring factors that facilitate participation of people with spinal cord injury (SCI) in travel-related activities: Removing Travel Restrictions Influencing Participation (ReTRIP). Design: A mixed-method approach where in the qualitative phase, items were developed and written based on results of interviewers with different stakeholder groups and in the quantitative phase, survey data were collected to examine the psychometric properties of the scale. Setting: Home, work, and community settings. Participants: People living with SCI, caregivers or family members, therapists, travel professionals (N=333). Interventions: None. Main Outcome Measures: An 11-item ReTRIP scale that measures the facilitators that enhance the travel participation of people with SCI. Results: In the qualitative phase of the study, 5 categories of travel facilitators were identified based on semistructured in-depth interviews with 83 respondents from 4 stakeholder groups. Initial items of the ReTRIP scale were written based on the travel facilitators identified. Items in the scale were then revised based on results of cognitive interviews and an expert panel review. In the quantitative phase, a total of 250 patients enrolled in a Spinal Cord Injury Model System were systematically selected to report their experience with each travel facilitator. Item-response theory–based Rasch analysis revealed that the 11-item ReTRIP has acceptable psychometric properties, containing 2 main dimensions: industry-oriented facilitators (6 items) and self-oriented facilitators (5 items). Conclusions: The 11-item ReTRIP scale demonstrates promising psychometric properties, allowing researchers and clinicians to potentially use self-reported environmental factors that are beneficial for people’s participation in travel after SCI to properly design client-centered interventions. Future studies using a larger sample are needed to validate the scale

Results Files for Svetina and Dai, Journal of Experimental Education

Results related to Number of Response Categories and Sample Size Requirements in Polytomous IRT Models by Dubravka Svetina Valdivia and Shenghai Dai, published in the Journal of Experimental Education, https://doi.org/10.1080/00220973.2022.2153783  </p

Read me file - please read first

This file shows a roadmap to other files included in the project for researchers use.</p

Simulation Study Code and Results Files for Svetina and Dai Paper, Journal of Experimental Education

Read me file, Simulation Study and Results files related to Number of Response Categories and Sample Size Requirements in Polytomous IRT Models by Dubravka Svetina Valdivia and Shenghai Dai, published in the Journal of Experimental Education, https://doi.org/10.1080/00220973.2022.2153783  </p

Investigation of Missing Responses in Q-Matrix Validation

Missing data can be a serious issue for practitioners and researchers who are tasked with Q-matrix validation analysis in implementation of cognitive diagnostic models. The article investigates the impact of missing responses, and four common approaches (treat as incorrect, logistic regression, listwise deletion, and expectation–maximization [EM] imputation) for dealing with them, on the performance of two major Q-matrix validation methods (the EM-based δ-method and the nonparametric Q-matrix refinement method) across multiple factors. Results of the simulation study show that both validation methods perform better when missing responses are imputed using EM imputation or logistic regression instead of being treated as incorrect and using listwise deletion. The nonparametric Q-matrix validation method outperforms the EM-based δ-method in most conditions. Higher missing rates yield poorer performance of both methods. Number of attributes and items have an impact on performance of both methods as well. Results of a real data example are also discussed in the study

The Effects of Collapsing Ordered Categorical Variables on Tests of Measurement Invariance

Cross-cultural comparisons of latent variable means demands equivalent loadings and intercepts or thresholds. Although equivalence generally emphasizes items as originally designed, researchers sometimes modify response options in categorical items. For example, substantive research interests drive decisions to reduce the number of item categories. Further, categorical multiple-group confirmatory factor analysis (MG-CFA) methods generally require that the number of indicator categories is equal across groups; however, categories with few observations in at least one group can cause challenges. In the current paper, we examine the impact of collapsing ordinal response categories in MG-CFA. An empirical analysis and a complementary simulation study suggests meaningful impacts on model fit due to collapsing categories. We also found reduced scale reliability, measured as a function of Fisher’s information. Our findings further illustrate artifactual fit improvement, pointing to the possibility of data dredging for improved model-data consistency in challenging invariance contexts with large numbers of groups

The Longitudinal Relationship Between Levels of Cognitively Stimulating Leisure Activity and Positive and Negative Affect Among Older Adults With MCI

Background The purpose of this study was to investigate the longitudinal relationship between different levels of cognitively stimulating leisure activity (CSLA) participation and different levels of positive and negative affect among older adults with mild cognitive impairment (MCI). Methods Using a repeated-measured multivariate analysis of covariance (RM-MANCOVA), this study analyzed the Health and Retirement Study (HRS) data from 2012 to 2020 (N = 5932). Results The results presented the following. (a) The high CSLA group showed higher positive affect and lower negative affect than the mid and low groups. Also, the mid-CSLA group presented higher positive affect and lower negative affect than the low CSLA group. (b) Both positive and negative affect showed significant differences between years and indicated a continuously declining slope year by year without exceptions. (c) The high CSLA group not only presented higher positive affect and lower negative affect during the period but also solely showed a rebounding feature in the declining slope on both emotions. Conclusions The findings of this study provide valuable support for the design and implementation of CSLA participation programs and clinical guidelines for older adults with MCI. The results highlight the importance of determining the optimal level of CSLA engagement that is required to promote emotional health and cognitive function in this population. Healthcare professionals and clinical practitioners can leverage the insights gained from this study to develop and deliver effective CSLA interventions tailored to the specific needs and capacities of older adults with MCI