Tag: nevin manimala

Stat Med. 2022 Aug 26. doi: 10.1002/sim.9562. Online ahead of print.

ABSTRACT

Network meta-analysis (NMA) of rare events has attracted little attention in the literature. Until recently, networks of interventions with rare events were analyzed using the inverse-variance NMA approach. However, when events are rare the normal approximations made by this model can be poor and effect estimates are potentially biased. Other methods for the synthesis of such data are the recent extension of the Mantel-Haenszel approach to NMA or the use of the noncentral hypergeometric distribution. In this article, we suggest a new common-effect NMA approach that can be applied even in networks of interventions with extremely low or even zero number of events without requiring study exclusion or arbitrary imputations. Our method is based on the implementation of the penalized likelihood function proposed by Firth for bias reduction of the maximum likelihood estimate to the logistic expression of the NMA model. A limitation of our method is that heterogeneity cannot be taken into account as an additive parameter as in most meta-analytical models. However, we account for heterogeneity by incorporating a multiplicative overdispersion term using a two-stage approach. We show through simulation that our method performs consistently well across all tested scenarios and most often results in smaller bias than other available methods. We also illustrate the use of our method through two clinical examples. We conclude that our “penalized likelihood NMA” approach is promising for the analysis of binary outcomes with rare events especially for networks with very few studies per comparison and very low control group risks.

PMID:36054668 | DOI:10.1002/sim.9562

Am J Hematol. 2022 Aug 28. doi: 10.1002/ajh.26703. Online ahead of print.

ABSTRACT

It is well established that splenic dysfunction occurs in early childhood in sickle cell anemia (SCA), although the determinants and consequences of splenic injury are not fully understood. In this study, we examined spleen size and splenic function in 100 children with SCA aged 0 to 16 years at King’s College Hospital in London. Spleen size was assessed by abdominal ultrasound and splenic function by pitted red blood cells (PIT counts). In our cohort, 5.6% of children aged 6 to 10 years and 19.4% of children aged 11 to 16 years had no visible spleen on ultrasound (autosplenectomy). Splenomegaly was common in all age groups, with 28% of children overall having larger spleens than the average for their age. Only one child had a PIT count suggesting preserved splenic function. We found no correlation between hemoglobin F levels and spleen size, nor was there any difference in spleen size between children treated with or without hydroxyurea. Although there was a trend towards increased spleen length in children with co-inherited α-thalassemia, this did not reach statistical significance. Finally, we found a strong association between erythrocyte deformability measured with oxygen gradient ektacytometry, spleen size, and PIT counts. In conclusion, our results do not agree with the general perception that most children with SCA undergo autosplenectomy within the first decade of life and indicate that loss of erythrocyte deformability contributes to loss of splenic filtration capacity in SCA, as well as phenotypical variations in spleen size. This article is protected by copyright. All rights reserved.

PMID:36054667 | DOI:10.1002/ajh.26703

J Dent Educ. 2022 Sep 2. doi: 10.1002/jdd.13087. Online ahead of print.

ABSTRACT

PURPOSE: In 2021, the American Dental Association (ADA) announced the intention to develop a standardized dental hygiene licensure objective structured clinical examination (DHLOSCE). The purpose of this study was to measure the United States (US) dental hygiene (DH) educators’ foundational knowledge of OSCE development and delivery in light of the impending development of the DHLOSCE by the ADA’s Testing Services.

METHODS: The study was determined to be exempt from Institutional Review Board oversight. A 21-question survey was developed, pilot tested, and electronically disseminated through Qualtrics. The survey recruitment was emailed to the directors of all entry-level DH education programs in the US (n = 328), asking them to participate in the survey and to forward it to the clinical faculty in their institutions. Descriptive and inferential statistics were utilized to analyze the data.

RESULTS: There were 143 study participants, for a completion rate of 45%. Over two-thirds of respondents (64%) were unaware of the plans to develop the DHLOSCE, while 13% reported utilizing OSCEs to meet accreditation standards. Only 3% reported receiving a formal education in OSCE development compared to 29% who learned through a colleague or peer. Nearly half reported a lack of faculty experience as a barrier to OSCE implementation. Over three-quarters, 76% reported a lack of OCSE development committees within their program and only 14% had experience developing an OSCE station.

CONCLUSION: The study results suggest an urgent need for the development of OSCE training resources specific to DH education, as programs across the US prepare for the impending DHLOSCE.

PMID:36052838 | DOI:10.1002/jdd.13087

Crit Rev Food Sci Nutr. 2022 Sep 2:1-19. doi: 10.1080/10408398.2022.2117786. Online ahead of print.

ABSTRACT

Various methodologies including genetic analyses, morphometrics, proteomics, lipidomics, metabolomics, etc. are now used or being developed to authenticate fish and seafood. Such techniques usually lead to the generation of enormous amounts of data. The analysis and interpretation of this information can be particularly challenging. Statistical techniques are therefore commonly used to assist in analyzing these data, visualizing trends and differences and extracting conclusions. This review article aims at presenting and discussing statistical methods used in studies on fish and seafood authenticity and adulteration, allowing researchers to consider their options based on previous successes/failures but also offering some recommendations about the future of such techniques. Techniques such as PCA, AMOVA and F_ST statistics, that allow the differentiation of genetic groups, or techniques such as MANOVA that allow large data sets of morphometric characteristics or elemental differences to be analyzed are discussed. Furthermore, methods such as cluster analysis, DFA, CVA, CDA and heatmaps/Circos plots that allow samples to be differentiated based on their geographical origin are also reviewed and their advantages and disadvantages as found in past studies are given. Finally, mathematical simulations and modeling are presented in a detailed review of studies using them, together with their advantages and limitations.

PMID:36052815 | DOI:10.1080/10408398.2022.2117786

Ying Yong Sheng Tai Xue Bao. 2022 Jul;33(7):1937-1947. doi: 10.13287/j.1001-9332.202207.019.

ABSTRACT

In this study, the biomass models for natural Quercus mongolica in Heilongjiang Province were constructed based on the predictors of diameter at breast height (D) and tree height (H) by several methods including multivariate likelihood analysis and seemingly unrelated regression. The results showed that the H could significantly improve the stem biomass model, with the coefficient of determination (R²) being increased from 0.953 to 0.988 and the root mean square error (RMSE) being reduced by 14 kg, but it had no significant improvement for the biomass model of branch, foliage, and root. The error structures of both biomass model systems (only D and D–H) were multiplicative, indicating that the linear models after logarithmic transformation were more appropriate. The R² for the biomass models of stem, branch, foliage and root were 0.953-0.988, 0.982-0.983, 0.916-0.917, and 0.951-0.952, while the RMSE were 13.42-27.03, 6.84-7.00, 1.95-1.97 and 9.71-9.84 kg. Compared with the feasible generalized least squares (FGLS) approach, Bayesian estimation had similar fitting performance and provided parameter estimates with different variations. The standard errors of parameters for FGLS were 0.054-0.211. There were similar variations (standard deviations of 0.055-0.221) for the two Bayesian estimation with no prior information (DMC and Gibbs1). The Gibbs sampler with a multivariate normal distribution with a mean vector of 0, variances of 1000 and covariances of 0 (Gibbs2) or the prior information from the historical researches summary for Quercus trees biomass models (Gibbs3) produced greater variation than those of FGLS, DMC, and Gibbs1 (stan-dard deviations were 0.080-0.278), while Gibbs sampler with the prior information obtained from own data (Gibbs4) provided the lower variations than others (standard deviations were 0.004-0.013). The Gibbs4 approach provided the narrowest 95% prediction interval and produced the smaller prediction biases, with the average absolute error percentage (MAPE) for stem, branch, foliage, root and total of the only-D biomass model being 19.8%, 24.7%, 24.6%, 29.0% and 13.1%, while MAPE for the corresponding components of D-H biomass model kept same except for stem and total decreased to 10.5% and 9.8%, which indicated that Gibbs4 could provide more accurate biomass predictions. Compared with classical statistics, accurate prior information made Bayesian seemingly unrelated regression an advantage in estimation stability and uncertainty reduction.

PMID:36052798 | DOI:10.13287/j.1001-9332.202207.019

Photodermatol Photoimmunol Photomed. 2022 Sep 2. doi: 10.1111/phpp.12832. Online ahead of print.

ABSTRACT

BACKGROUND: Few studies have reported postoperative relapse of condyloma acuminatum (CA) after 5-aminolevulinic acid photodynamic therapy (ALA-PDT) in human immunodeficiency virus (HIV) positive patients.

METHODS: The clinical data of HIV-positive CA patients treated with ALA-PDT from October 2018 to December 2019 were analyzed retrospectively. Univariate and multivariate Cox regression was used to analyze the variables related to postoperative recurrence. Pearson correlation test was employed to analyze the correlation between CD4⁺ T cell count and postoperative recurrence rate. Kaplan-Meier method was used to compare the CA recurrence after ALA-PDT in low CD4 group and high CD4 group.

RESULTS: A total of 38 HIV-positive patients with CA were included in the study. Among them, 26 patients experienced CA recurrence within 6 months, and the recurrence rate was 68.4%. CD4⁺ T cell count was 187.0 (79.0-596.0) cells/uL in relapsed patients and 406.0 (89.0-612.0) cells/uL in non-relapsed patients, showing a statistically significant difference (P=0.005). Pearson correlation coefficient analysis revealed a negative correlation between CD4⁺ T cell count and postoperative recurrence rate (P = 0.005, r = -0.443). Univariate regression analysis showed that CD4⁺ T cell count was correlated with postoperative recurrence, hazard ratio (HR) was 0.99 [95% Confidence interval (CI) = 0.99-1.0, P=0.012]. Multivariate Cox regression analysis showed that with the low CD4⁺ T cell count as the reference, the high CD4⁺ T cell count was negatively correlated with postoperative recurrence (HR=0.09, 95% CI 0.01- 0.87, P =0.038).

CONCLUSIONS: Peripheral blood CD4⁺ T cell count can predict the CA recurrence rate after ALA-PDT in HIV-positive patients.

PMID:36052757 | DOI:10.1111/phpp.12832

Biomark Med. 2022 Sep 2. doi: 10.2217/bmm-2022-0368. Online ahead of print.

ABSTRACT

Aim: The aim of this study was to measure serum levels of methylarginine derivatives and related metabolites in patients with gout. Materials & methods: This study enrolled 100 patients with gout and 80 patients in the control group. Serum asymmetric dimethylarginine, symmetric dimethylarginine, L-N-monomethylarginine, arginine, homoarginine, citrulline and ornithine levels were measured with tandem mass spectrometry. Results: Serum ornithine, citrulline and total methylated arginine load levels were statistically significantly higher in patients with gout compared with the control group, while serum arginine and homoarginine levels and global arginine bioavailability ratio were statistically significantly lower. Conclusion: There may be an association between gout, methylarginine levels and hyperuricemia and increased risk of cardiovascular disease.

PMID:36052727 | DOI:10.2217/bmm-2022-0368

Transfusion. 2022 Sep 2. doi: 10.1111/trf.17081. Online ahead of print.

ABSTRACT

BACKGROUND: Bacterial contamination in platelets remain a major public health concern, which prompted the US Food and Drug Administration guidance for bacterial contamination mitigation. Pathogen reduction technology (PRT) is one mitigation strategy that has shown success in Europe over the last decade. Therefore, our center sought to transition from a dual system of bacterial culturing (BacT) and PRT to full PRT.

METHODS: A 1 month pilot study was conducted to simulate 100% PRT conditions. Our center also collected baseline data on key platelet production metrics in the 4 months prior to 100% PRT and compared it to the 4 months post-implementation.

RESULTS: The pilot study showed no statistical differences in split rate, proportion of low-yield products, or proportion of single, double, and triple collections. The only observed difference was an 11 min increase in the average duration of double collections. Our baseline versus post-implementation monitoring showed no difference in split rate, discard rate, percentage of low-yield units, and average yield of low yield units. Statistical differences were detected in the proportion of single, double, and triple collections, as well as the average yield of full dose products. Roughly 20% of our inventory consisted of low-yield products.

DISCUSSION: With suitable mitigation strategies, transitioning to a full PRT inventory may result in higher net margins while not adversely affecting overall platelet production. A pilot study is a good way to project potential effects of switching from a dual BacT and PRT inventory to full PRT, and can be adopted by other centers aiming to make the transition.

PMID:36052676 | DOI:10.1111/trf.17081

J Esthet Restor Dent. 2022 Sep 2. doi: 10.1111/jerd.12959. Online ahead of print.

ABSTRACT

BACKGROUND: The prosthetic screw fixes the prostheses to the implants. Upon osteointegration, the untightening of the prosthetic screw is the most common problem in oral rehabilitation with implants.

OBJECTIVE: To study the deformation of the implant retaining hexagonal screw head.

METHODS: This investigation used two methods for evaluating the screw head’s area of deformation (mm² ): a stereoscopic microscopy and micro computed tomography (microCT). For stereoscopic microscopy, 16 titanium alloy (T) and 16 titanium gold-plated alloy (G) screws of the Zimmer Biomet™ brand were used, divided into eight groups: group 0 (control group), groups T1 and G1 (screws tightened 10 times to 20 Ncm), the groups T2 and G2 (screws tightened 20 times to 20 Ncm) and the groups T3 and G3 (screws tightened 10 times to 30 Ncm). In the study with microCT, one screw was randomly chosen from each of the groups described above to perform the scanning by microCT.

RESULTS: When comparing the type of screw material using stereoscopic microscopy, no statistically significant differences were found (p > 0.05). Contrarily, different number of successive grips and different torque value showed statistically significant differences in the head section of the retaining screws (p < 0.05). The observation by microCT showed the torque applied is crucial to the head deformation in titanium screws. In gold-plated screws the successive tightening appears to be pivotal.

CONCLUSION: Titanium and gold screws tend to behave similarly. By increasing the tightening cycles and the torque values of protocols greater levels of deformations can be expected. In general, microCT data showed better results for gold-plated titanium alloy.

CLINICAL SIGNIFICANCE: To control severe screw head deformation and the impossibility of untightening the implant’s restoration, clinicians should avoid extreme torque values and prevent surpassing 10 tightening cycles.

PMID:36052667 | DOI:10.1111/jerd.12959

Biomark Med. 2022 Sep 2. doi: 10.2217/bmm-2022-0265. Online ahead of print.

ABSTRACT

Aim: The study investigated heparin-binding protein (HBP) levels in patients with severe COVID-19 pneumonia and their relation to prognosis. Methods: A total of 134 patients with serious COVID-19 pneumonia were prospectively analyzed. HBP levels were statistically compared between both the patient and healthy control groups and within the patient group itself. Results: HBP was defined to be significantly higher in the patient group compared with the control group. There was a statistically significant distinction between the patients who survived and those who died with regard to HBP levels. When the cutoff value of HBP was >13.47, sensitivity (89.8%), specificity (74.1%) had area under the curve values of 0.806 (p < 0.001). Conclusion: HBP level may be used for prognosis prediction of patients with COVID-19.

PMID:36052658 | DOI:10.2217/bmm-2022-0265