Nevin Manimala

Med Phys. 2023 May 10. doi: 10.1002/mp.16446. Online ahead of print.

ABSTRACT

BACKGROUND: Recent developments in alpha and beta emitting radionuclide therapy highlight the importance of developing efficient methods for patient-specific dosimetry. Traditional tabulated methods such as Medical Internal Radiation Dose (MIRD) estimate the dose at the organ level while more recent numerical methods based on Monte Carlo (MC) simulations are able to calculate dose at the voxel level. A precalculated MC (PMC) approach was developed in this work as an alternative to time-consuming fully simulated MC. Once the spatial distribution of alpha and beta emitters is determined using imaging and/or numerical methods, the PMC code can be used to achieve an accurate voxelized 3D distribution of the deposited energy without relying on full MC calculations.

PURPOSE: To implement the PMC method to calculate energy deposited by alpha and beta particles emitted from the Ra-224 decay chain.

METHODS: The GEANT4 (version 10.7) MC toolkit was used to generate databases of precalculated tracks to be integrated in the PMC code as well as to benchmark its output. In this regard, energy spectra of alpha and beta particles emitted by the Ra-224 decay chain were generated using GAMOS (version 6.2.0) and imported into GEANT4 macro files. Either alpha or beta emitting sources were defined at the center of a homogeneous phantom filled with various materials such as soft tissue, bone, and lung where particles were emitted either mono-directionally (for database generation) or isotropically (for benchmarking). Two heterogeneous phantoms were used to demonstrate PMC code compatibility with boundary crossing events. Each precalculated database was generated step-by-step by storing particle track information from GEANT4 simulations followed by its integration in a PMC code developed in MATLAB. For a user-defined number of histories, one of the tracks in a given database was selected randomly and rotated randomly to reflect an isotropic emission. Afterward, deposited energy was divided between voxels based on step length in each voxel using a ray-tracing approach. The radial distribution of deposited energy was benchmarked against fully simulated MC calculations using GEANT4. The effect of the GEANT4 parameter StepMax on the accuracy and speed of the code was also investigated.

RESULTS: In the case of alpha decay, primary alpha particles show the highest contribution (>99%) in deposited energy compared to their secondary particles. In most cases, protons act as the main secondary particles in the deposition of energy. However, for a lung phantom, using a range cutoff parameter of 10 µm on primary alpha particles yields a higher contribution of secondary electrons than protons. Differences between deposited energy calculated by PMC and fully simulated MC are within 2% for all alpha and beta emitters in homogeneous and heterogeneous phantoms. Additionally, statistical uncertainties are less than 1% for voxels with doses higher than 5% of the maximum dose. Moreover, optimization of the parameter StepMax is necessary to achieve the best tradeoff between code accuracy and speed.

CONCLUSIONS: The PMC code shows good performance for dose calculations deposited by alpha and beta emitters. As a stand-alone algorithm, it is suitable to be integrated into clinical treatment planning systems.

PMID:37161766 | DOI:10.1002/mp.16446

Stat Methods Med Res. 2023 May 10:9622802231172043. doi: 10.1177/09622802231172043. Online ahead of print.

ABSTRACT

For clinical studies with continuous outcomes, when the data are potentially skewed, researchers may choose to report the whole or part of the five-number summary (the sample median, the first and third quartiles, and the minimum and maximum values) rather than the sample mean and standard deviation. In the recent literature, it is often suggested to transform the five-number summary back to the sample mean and standard deviation, which can be subsequently used in a meta-analysis. However, if a study contains skewed data, this transformation and hence the conclusions from the meta-analysis are unreliable. Therefore, we introduce a novel method for detecting the skewness of data using only the five-number summary and the sample size, and meanwhile, propose a new flow chart to handle the skewed studies in a different manner. We further show by simulations that our skewness tests are able to control the type I error rates and provide good statistical power, followed by a simulated meta-analysis and a real data example that illustrate the usefulness of our new method in meta-analysis and evidence-based medicine.

PMID:37161735 | DOI:10.1177/09622802231172043

Stat Med. 2023 May 10. doi: 10.1002/sim.9765. Online ahead of print.

ABSTRACT

A key goal of environmental health research is to assess the risk posed by mixtures of pollutants. As epidemiologic studies of mixtures can be expensive to conduct, it behooves researchers to incorporate prior knowledge about mixtures into their analyses. This work extends the Bayesian multiple index model (BMIM), which assumes the exposure-response function is a nonparametric function of a set of linear combinations of pollutants formed with a set of exposure-specific weights. The framework is attractive because it combines the flexibility of response-surface methods with the interpretability of linear index models. We propose three strategies to incorporate prior toxicological knowledge into construction of indices in a BMIM: (a) imposing directional homogeneity constraints on the weights, (b) structuring index weights by exposure transformations, and (c) placing informative priors on the index weights. We propose a novel prior specification that combines spike-and-slab variable selection with an informative Dirichlet distribution based on relative potency factors often derived from previous toxicological studies. In simulations we show that the proposed priors improve inferences when prior information is correct and can protect against misspecification suffered by naïve toxicological models when prior information is incorrect. Moreover, different strategies may be mixed-and-matched for different indices to suit available information (or lack thereof). We demonstrate the proposed methods on an analysis of data from the National Health and Nutrition Examination Survey and incorporate prior information on relative chemical potencies obtained from toxic equivalency factors available in the literature.

PMID:37161723 | DOI:10.1002/sim.9765

Hosp Pediatr. 2023 May 10:e2022006990. doi: 10.1542/hpeds.2022-006990. Online ahead of print.

ABSTRACT

OBJECTIVES: Conflict management skills are essential for interprofessional team functioning, however existing trainings are time and resource intensive. We hypothesized that a curriculum incorporating virtual reality (VR) simulations would enhance providers’ interprofessional conflict communication skills and increase self-efficacy.

METHODS: We conducted a randomized controlled pilot study of the Conflict Instruction through Virtual Immersive Cases (CIVIC) curriculum among inpatient clinicians at a pediatric satellite campus. Participants viewed a 30-minute didactic presentation on conflict management and subsequently completed CIVIC (intervention group) or an alternative VR curriculum on vaccine counseling (control group), both of which allowed for verbal interactions with screen-based avatars. Three months following VR training, all clinicians participated in a unique VR simulation focused on conflict management that was recorded and scored using a rubric of observable conflict management behaviors and a Global Entrustment Scale (GES). Differences between groups were evaluated using generalized linear models. Self-efficacy was also assessed immediately pre, post, and 3 months postcurriculum. Differences within and between groups were assessed with paired independent and 2-sample t-tests, respectively.

RESULTS: Forty of 51 participants (78%) completed this study. The intervention group (n = 17) demonstrated better performance on the GES (P = .003) and specific evidence-based conflict management behaviors, including summarizing team member’s concerns (P = .02) and checking for acceptance of the plan (P = .02), as well as statistical improvements in 5 self-efficacy measures compared with controls.

CONCLUSIONS: Participants exposed to CIVIC demonstrated enhanced conflict communication skills and reported increased self-efficacy compared with controls. VR may be an effective method of conflict communication training.

PMID:37161716 | DOI:10.1542/hpeds.2022-006990

Pediatrics. 2023 May 10:e2021056140. doi: 10.1542/peds.2021-056140. Online ahead of print.

ABSTRACT

OBJECTIVES: Describe characteristics of gastroenteritis, bacteremia, and meningitis caused by nontyphoidal Salmonella among US infants.

METHODS: We analyze national surveillance data during 1968-2015 and active, sentinel surveillance data during 1996-2015 for culture-confirmed Salmonella infections by syndrome, year, serotype, age, and race.

RESULTS: During 1968-2015, 190 627 culture-confirmed Salmonella infections among infants were reported, including 165 236 (86.7%) cases of gastroenteritis, 6767 (3.5%) bacteremia, 371 (0.2%) meningitis, and 18 253 (9.7%) with other or unknown specimen sources. Incidence increased during the late 1970s-1980s, declined during the 1990s-early 2000s, and has gradually increased since the mid-2000s. Infants’ median age was 4 months for gastroenteritis and bacteremia and 2 months for meningitis. The most frequently reported serotypes were Typhimurium (35 468; 22%) for gastroenteritis and Heidelberg for bacteremia (1954; 29%) and meningitis (65; 18%). During 1996-2015 in sentinel site surveillance, median annual incidence of gastroenteritis was 120, bacteremia 6.2, and meningitis 0.25 per 100 000 infants. Boys had a higher incidence of each syndrome than girls in both surveillance systems, but most differences were not statistically significant. Overall, hospitalization and fatality rates were 26% and 0.1% for gastroenteritis, 70% and 1.6% for bacteremia, and 96% and 4% for meningitis. During 2004-2015, invasive salmonellosis incidence was higher for Black (incident rate ratio, 2.7; 95% confidence interval, 2.6-2.8) and Asian (incident rate ratio, 1.8; 95% confidence interval, 1.7-1.8) than white infants.

CONCLUSIONS: Salmonellosis causes substantial infant morbidity and mortality; serotype heidelberg caused the most invasive infections. Infants with meningitis were younger than those with bacteremia or gastroenteritis. Research into risk factors for infection and invasive illness could inform prevention efforts.

PMID:37161700 | DOI:10.1542/peds.2021-056140

Turk J Pharm Sci. 2023 May 9;20(2):115-120. doi: 10.4274/tjps.galenos.2022.95994.

ABSTRACT

OBJECTIVES: Dexketoprofen is a non-steroidal analgesic/anti-inflammatory drug and its trometamol salt is extensively preferred in mild or moderate pain due to its rapid onset of relief. A new formulation of 36.9 mg of dexketoprofen trometamol (equivalent to 25 mg dexketoprofen) tablet has been developed and its bioequivalence to the reference product was proven.

MATERIALS AND METHODS: An open-label, single-dose, randomized, two-period, and cross-over bioequivalence study was conducted with healthy males under fasting conditions for two different tablet formulations of 25 mg dexketoprofen. To prove the bioequivalence of the test product with the reference product, a comparison study has been performed in compliance with regulations in force under Good Clinical Practice principles. A single-center clinical study was run and blood samples of the participants were withdrawn at specified time points, before and after dosing, to measure the plasma concentrations of dexketoprofen trometamol. A validated analytical method has been developed using an liquid chromatography with tandem mass spectrometry. Instrument to assess the plasma concentrations of the test and reference products.

RESULTS: Forty-seven volunteers completed clinical phase of the study. For the test and reference products, the mean ± standard deviations (SD) of C_max were found 2543.82 ± 655.42 ng/mL and 2539.11 ± 662.57 ng/mL, and the mean ± SD of area under the curve (AUC) from time 0 to the last measurable concentration (AUC_0-tlast) were found 3483.49 ± 574.42 h.ng/mL and 3560.75 ± 661.83 h.ng/mL, respectively. The primary target variables data demonstrate the bioequivalence of test and reference products with regard to 90% confidence interval for C_max of 92.45-108.53% and for AUC_0-tlast of 95.57-100.87%. The geometric mean ratios were found as 100.16% and 98.18% for C_max and AUC_0-tlast, respectively. There were no serious adverse events or adverse reactions reported throughout the study.

CONCLUSION: After statistical evaluation of the analytical results, the test and reference products were considered bioequivalent. Both products were well tolerated and considered as safe.

PMID:37161687 | DOI:10.4274/tjps.galenos.2022.95994

BJS Open. 2023 May 5;7(3):zrad010. doi: 10.1093/bjsopen/zrad010.

ABSTRACT

BACKGROUND: Electrolyte disturbances and dehydration are common after anterior resection for rectal cancer with a defunctioning loop ileostomy. High-quality population-based studies on the impact of a defunctioning loop ileostomy on renal failure are lacking.

METHODS: This was a nationwide observational study, based on the Swedish Colorectal Cancer Registry of patients undergoing anterior resection for rectal cancer between 2008 and 2016, with follow-up until 2017. Patients with severe co-morbidity, with age greater than 80 years, and with pre-existing renal failure were excluded. Loop ileostomy at index surgery constituted exposure, while a diagnosis of renal failure was the outcome. Acute and chronic events were analysed separately. Inverse probability weighting with adjustment for confounding derived from a causal diagram was employed. Hazards ratios (HRs) with 95 per cent c.i. are reported.

RESULTS: A total of 5355 patients were eligible for analysis. At 5-year follow-up, all renal failure events (acute and chronic) were 7.2 per cent and 3.3 per cent in the defunctioning stoma and no stoma groups respectively. In the weighted analysis, a HR of 11.59 (95 per cent c.i. 5.68 to 23.65) for renal failure in ostomates was detected at 1 year, with the largest effect from acute renal failure (HR 24.04 (95 per cent c.i. 8.38 to 68.93)). Later follow-up demonstrated a similar pattern, but with smaller effect sizes.

CONCLUSION: Patients having a loop ileostomy in combination with anterior resection for rectal cancer are more likely to have renal failure, especially early after surgery. Strategies are needed, such as careful fluid management protocols, and further research into alternative stoma types or reduction in stoma formation.

PMID:37161674 | DOI:10.1093/bjsopen/zrad010

BJS Open. 2023 May 5;7(3):zrad045. doi: 10.1093/bjsopen/zrad045.

ABSTRACT

BACKGROUND: The aim of this study was to compare the pathological and perioperative outcomes of extracorporeal versus intracorporeal anastomosis after laparoscopic transverse colon cancer resection.

METHODS: In this retrospective study, patients from seven institutions in China who underwent laparoscopic resection of transverse colon cancer between 2019 and 2021 were selected and included. Either extended right hemicolectomy or transverse colectomy/extended left hemicolectomy was performed. The clinical characteristics and the pathological and perioperative outcomes were compared between patients undergoing extracorporeal or intracorporeal anastomosis. Resection margin lengths were measured on formalin-fixed specimens and an inadequate margin was defined as less than 4.2 cm between the division and the tumour. The outcome of interest was the prevalence of specimens with an inadequate margin. Length of incision, bowel function recovery, hospital stay, early postoperative pain (first day after surgery), 30-day complications, and nodal harvest were investigated as secondary outcomes.

RESULTS: Of 411 patients treated during the study interval, 370 patients with transverse colon cancer were included (23.2 per cent treated with intracorporeal anastomosis and 76.8 per cent treated with extracorporeal anastomosis). The prevalence of specimens with inadequate margins was lower in the intracorporeal anastomosis group compared with the extracorporeal anastomosis group in patients undergoing extended right hemicolectomy (P = 0.045) and in patients undergoing transverse colectomy/extended left hemicolectomy (P = 0.030). In multivariate analysis, extracorporeal anastomosis (OR 2.94 (95 per cent c.i. 1.33 to 6.49), P = 0.008) and transverse colectomy/extended left hemicolectomy (OR 1.75 (95 per cent c.i. 1.03 to 2.96), P = 0.038) were independent risk factors for specimens with an inadequate margin. Intracorporeal anastomosis was associated with a shorter incision length (P < 0.001), an earlier recovery of bowel function (P = 0.035), a shorter postoperative hospital stay (P = 0.042), less early postoperative pain (P < 0.001), a longer specimen length (P = 0.042), a longer resection margin (P = 0.007), and a greater lymph node harvest (P = 0.036). There was no statistically significant difference in 30-day complications.

CONCLUSION: Patients with transverse colon cancer have better perioperative outcomes, fewer margins of less than 4.2 cm, and larger lymph node harvests when the anastomosis is performed intracorporeally. Further studies are needed to confirm these findings.

REGISTRATION NUMBER: NCT05061199 (www.clinicaltrials.gov).

PMID:37161672 | DOI:10.1093/bjsopen/zrad045

Gut Pathog. 2023 May 10;15(1):22. doi: 10.1186/s13099-023-00546-z.

ABSTRACT

BACKGROUND: Severe coronavirus disease 2019 (COVID-19) is associated with systemic hyper-inflammation. An adaptive interaction between gut microbiota and host immune systems is important for intestinal homeostasis and systemic immune regulation. The association of gut microbial composition and functions with COVID-19 disease severity is sparse, especially in India. We analysed faecal microbial diversity and abundances in a cohort of Indian COVID-19 patients to identify key signatures in the gut microbial ecology in patients with severe COVID-19 disease as well as in response to different therapies. The composition of the gut microbiome was characterized using 16Sr RNA gene sequences of genomic DNA extracted from faecal samples of 52 COVID-19 patients. Metabolic pathways across the groups were predicted using PICRUSt2. All statistical analyses were done using Vegan in the R environment. Plasma cytokine abundance at recruitment was measured in a multiplex assay.

RESULTS: The gut microbiome composition of mild and severe patients was found to be significantly different. Immunomodulatory commensals, viz. Lachnospiraceae family members and Bifidobacteria producing butyrate and short-chain fatty acids (SCFAs), were under represented in patients with severe COVID-19, with an increased abundance of opportunistic pathogens like Eggerthella. The higher abundance of Lachnoclostridium in severe disease was reduced in response to convalescent plasma therapy. Specific microbial genera showed distinctive trends in enriched metabolic pathways, strong correlations with blood plasma cytokine levels, and associative link to disease outcomes.

CONCLUSION: Our study indicates that, along with SARS-CoV-2, a dysbiotic gut microbial community may also play an important role in COVID-19 severity through modulation of host immune responses.

PMID:37161621 | DOI:10.1186/s13099-023-00546-z

J Diabetes. 2023 May 9. doi: 10.1111/1753-0407.13399. Online ahead of print.

ABSTRACT

BACKGROUND: Evidence links gamma-glutamyl transferase (GGT) to mortality in the general population. However, the relationship of GGT with all-cause and cause-specific mortality risk has been little explored in type 2 diabetes mellitus (T2DM) patients.

METHODS: We recruited 20 340 community-dwelling T2DM patients between 2013 and 2014 in Jiangsu, China. Cox regression models were used to assess associations of GGT with all-cause and specific-cause mortality. Restricted cubic splines were used to analyze dose-response relationships between GGT and mortality. Stratified analysis was conducted to examine potential interaction effects by age, sex, smoking status, body mass index (BMI), diabetes duration, and dyslipidemia.

RESULTS: During a median follow-up period of 7.04 years (interquartile range: 6.98-7.08), 2728 deaths occurred, including 902 (33.09%) due to cardiovascular disease (CVD), and 754 (27.58%) due to cancer. GGT concentrations were positively associated with all-cause, CVD, and cancer mortality. Multivariable hazard ratios (HRs) for the highest (Q5) vs. the lowest quintile (Q1) were 1.63 (95% confidence intervals [CI]: 1.44-1.84) for all-cause mortality, 1.87 (95% CI: 1.49-2.35) for CVD mortality, and 1.43 (95% CI: 1.13-1.81) for cancer mortality. Effect modification by BMI and dyslipidemia was observed for all-cause mortality (both p for interaction <.05), and HRs were stronger in the BMI <25 kg/m² group and those without dyslipidemia.

CONCLUSIONS: Our findings suggest that, in Chinese T2DM patients, elevated serum GGT concentrations were associated with mortality for all-cause, CVD, and cancer, and further research is needed to elucidate the role of obesity, nonalcoholic fatty liver disease, and lipids in this association.

PMID:37161588 | DOI:10.1111/1753-0407.13399