Comparative Analysis of Bone Regeneration According to Particle Type and Barrier Membrane for Octacalcium Phosphate Grafted into Rabbit Calvarial Defects.

This animal study was aimed to evaluate the efficacy of new bone formation and volume maintenance according to the particle type and the collagen membrane function for grafted octacalcium phosphate (OCP) in rabbit calvarial defects. The synthetic bone substitutes were prepared in powder form with 90% OCP and granular form with 76% OCP, respectively. The calvarial defects were divided into four groups according to the particle type and the membrane application. All specimens were acquired 2 weeks (n = 5) and 8 weeks (n = 5) after surgery. According to the micro-CT results, the new bone volume increased at 2 weeks in the 76% OCP groups compared to the 90% OCP groups, and the bone volume ratio was significantly lower in the 90% OCP group after 2 weeks. The histomorphometric analysis results indicated that the new bone area and its ratio in all experimental groups were increased at 8 weeks except for the group with 90% OCP without a membrane. Furthermore, the residual bone graft area and its ratio in the 90% OCP groups were decreased at 8 weeks. In conclusion, all types of OCP could be applied as biocompatible bone graft materials regardless of its density and membrane application. Neither the OCP concentration nor the membrane application had a significant effect on new bone formation in the defect area, but the higher the OCP concentration, the less graft volume maintenance was needed.

Inter- and intra-session variability of compression strain gauge for the adductor groin squeeze test on soccer athletes.

The importance of hip adductor strength for injury prevention and performance benefits is well documented. The purpose of this study was to establish the intra- and inter-day variability of peak force (PF) of a groin squeeze protocol using a custom-designed compression strain gauge device. Sixteen semi-professional soccer players completed three trials over three separate testing occasions with at least 24-h rest between each session. The main findings were that the compression strain gauge was a reliable device for measuring PF within and between days. All intraclass correlations were higher than 0.80 and coefficients of variations were below 10% across the different sessions and trials. Due to the information gained through the compression strain gauge, the higher sampling frequency utilized, portability, and the relatively affordable price, this device offers an effective alternative for measuring maximal strength for hip adduction.

Decentralized clinical trial design using blood microsampling technology for serum bioanalysis.

Background: Alternatives to phlebotomy in clinical trials increase options for patients and clinicians by simplifying and increasing accessibility to clinical trials. The authors investigated the technical and logistical considerations of one technology compared with phlebotomy. Methodology: Paired samples were collected from 16 donors via a second-generation serum gel microsampling device and conventional phlebotomy. Microsamples were subject to alternative sample handling conditions and were evaluated for quality, clinical testing and proteome profiling. Results: Timely centrifugation of blood serum microsamples largely preserved analyte stability. Conclusion: Centrifugation timing of serum microsamples impacts the quality of specific clinical chemistry and protein biomarkers. Microsampling devices with remote centrifugation and refrigerated shipping can decrease patient burden, expand clinical trial populations and aid clinical decisions.

Experiences with Racism Among Asian American Medical Students.

Importance: Asian American physicians have experienced a dual pandemic of racism and COVID-19 since 2020; understanding how racism has affected the learning environment of Asian American medical students is necessary to inform strategies to promoting a more inclusive medical school environment and a diverse and inclusive workforce. While prior research has explored the influence of anti-Asian racism on the experiences of Asian American health care workers, to our knowledge there are no studies investigating how racism has impacted the training experiences of Asian American medical students. Objective: To characterize how Asian American medical students have experienced anti-Asian racism in a medical school learning environment. Design, Setting, and Participants: This qualitative study included online video interviews of Asian American medical students performed between July 29, 2021, and August 22, 2022. Eligible participants were recruited through the Asian Pacific American Medical Students Association and snowball sampling, and the sample represented a disaggregated population of Asian Americans and all 4 medical school years. Main Outcomes and Measures: The medical school experiences of Asian American medical students. Results: Among 25 participants, Asian ethnicities included 8 Chinese American (32%), 5 Korean American (20%), 5 Indian American (20%), 3 Vietnamese American (12%), 2 Filipino American (8%), and 1 (4%) each Nepalese, Pakistani, and Desi American; 16 (64%) were female. Participants described 5 major themes concerning their experience with discrimination: (1) invisibility as racial aggression (eg, "It took them the whole first year to be able to tell me apart from the other Asian guy"); (2) visibility and racial aggression ("It transitioned from these series of microaggressions that every Asian person felt to actual aggression"); (3) absence of the Asian American experience in medical school ("They're not going to mention Asian Americans at all"); (4) ignored while seeking support ("I don't know what it means to have this part of my identity supported"); and (5) envisioning the future. Conclusions and Relevance: In this qualitative study, Asian American medical students reported feeling invisible within medical school while a target of anti-Asian racism. Addressing these unique challenges related to anti-Asian racism is necessary to promote a more inclusive medical school learning environment.

Atraumatic versus cutting needles in fluoroscopic lumbar puncture.

OBJECTIVES: Atraumatic needles are known to reduce complication rates of blind lumbar punctures (LP), however, their use in fluoroscopically guided LP is less studied. This study assessed the comparative difficulty of performing fluoroscopic lumbar puncture with atraumatic needles. METHODS: Single-centre retrospective case-control study comparing atraumatic and conventional or "cutting" needles using fluoroscopic time and radiation dose (Dose Area Product or DAP) as surrogate markers. Patients were assessed from two comparable eight-month periods before and after a policy change to primary use of atraumatic needles. RESULTS: 105 procedures with a cutting needle were performed in the group prior to the policy change. Median fluoroscopy time was 48 sec and median DAP was 3.14. Of 102 procedures performed in the group after the policy change, 99 were performed with an atraumatic needle and three with a cutting needle after initial attempt with an atraumatic needle. Median fluoroscopy time was 41 sec and median DAP was 3.28. The mean number of attempts was 1.02 in the cutting needle group and 1.05 in the atraumatic needle group. There was no significant difference in median fluoroscopy time, median DAP, or mean number of attempts. CONCLUSION: Fluoroscopic screening time, DAP and mean number of attempts were not significantly increased with primary use of atraumatic needles for LP. Use of atraumatic needles should be considered in fluoroscopic LP given the lower complication rates. ADVANCES IN KNOWLEDGE: This study provides new data showing that the use of atraumatic needles does not increase the difficulty of fluoroscopically guided LP.

Blueprint for antibody biologics developability.

Large-molecule antibody biologics have revolutionized medicine owing to their superior target specificity, pharmacokinetic and pharmacodynamic properties, safety and toxicity profiles, and amenability to versatile engineering. In this review, we focus on preclinical antibody developability, including its definition, scope, and key activities from hit to lead optimization and selection. This includes generation, computational and in silico approaches, molecular engineering, production, analytical and biophysical characterization, stability and forced degradation studies, and process and formulation assessments. More recently, it is apparent these activities not only affect lead selection and manufacturability, but ultimately correlate with clinical progression and success. Emerging developability workflows and strategies are explored as part of a blueprint for developability success that includes an overview of the four major molecular properties that affect all developability outcomes: 1) conformational, 2) chemical, 3) colloidal, and 4) other interactions. We also examine risk assessment and mitigation strategies that increase the likelihood of success for moving the right candidate into the clinic.

Photo-crosslinked gelatin methacryloyl hydrogel strengthened with calcium phosphate-based nanoparticles for early healing of rabbit calvarial defects.

PURPOSE: The aim of this study was to investigate the efficacy of photo-crosslinked gelatin methacryloyl (GelMa) hydrogel containing calcium phosphate nanoparticles (CNp) when applying different fabrication methods for bone regeneration. METHODS: Four circular defects were created in the calvaria of 10 rabbits. Each defect was randomly allocated to the following study groups: 1) the sham control group, 2) the GelMa group (defect filled with crosslinked GelMa hydrogel), 3) the CNp-GelMa group (GelMa hydrogel crosslinked with nanoparticles), and 4) the CNp+GelMa group (crosslinked GelMa loaded with nanoparticles). At 2, 4, and 8 weeks, samples were harvested, and histological and micro-computed tomography analyses were performed. RESULTS: Histomorphometric analysis showed that the CNp-GelMa and CNp+GelMa groups at 2 weeks had significantly greater total augmented areas than the control group (P<0.05). The greatest new bone area was observed in the CNp-GelMa group, but without statistical significance (P>0.05). Crosslinked GelMa hydrogel with nanoparticles exhibited good biocompatibility with a minimal inflammatory reaction. CONCLUSIONS: There was no difference in the efficacy of bone regeneration according to the synthesized method of photo-crosslinked GelMa hydrogel with nanoparticles. However, these materials could remain within a bone defect up to 2 weeks and showed good biocompatibility with little inflammatory response. Further improvement in mechanical properties and resistance to enzymatic degradation would be needed for the clinical application.

The acceptability and usability of two HIV self-test kits among men who have sex with men: a randomised crossover trial.

OBJECTIVES: To compare the usability and acceptability of oral fluid- and blood-based HIV self-test kits among men who have sex with men in Australia. DESIGN: Randomised crossover trial. SETTING, PARTICIPANTS: Gay, bisexual, and other men aged 18 years or older who have sex with men, who attended two metropolitan sexual health clinics in Sydney and Melbourne, 7 January - 10 December 2019. MAIN OUTCOME MEASURES: Ease of use of HIV self-test kits; preferred HIV self-test type; difficulties encountered during HIV self-testing. RESULTS: 170 men were recruited (median age, 34 years; interquartile range, 29-43 years); 144 identified as gay (85%), 96 were born outside Australia (57%). Participants were more likely to report the oral fluid HIV self-test was easy to use than the blood-based self-test (oral fluid, 99%; blood, 86%; odds ratio [OR], 3.0; 95% confidence interval [CI], 1.4-6.6). The oral fluid test was preferred by 98 participants (58%; 95% CI, 50-65%), the blood-based test by 69 (41%; 95% CI, 33-48%). Difficulties with the oral fluid test kit identified by observing nurses included problems placing the buffer solution into the stand (40 of 170 participants, 24%) and not swabbing both gums (23 of 169, 14%); difficulties with the blood-based test kit included problems filling the device test channel (69 of 170, 41%) and squeezing the finger firmly enough to generate a blood drop (42 of 170, 25%). No participant received an invalid result with the oral fluid self-test; two of 162 participants (1%) received invalid results with the blood self-test. After adjusting for age, education level, and ethnic background, characteristics associated with higher odds of using HIV self-testing in the future were overseas birth (adjusted OR, 3.07; 95% CI, 1.42-6.64), and self-evaluated ease of use and confidence in using the kits. CONCLUSION: It is important to provide options for obtaining both oral fluid- and blood-based HIV self-tests. The usability and acceptability of both kits were high, but the ease of use and perceived accuracy influenced test kit preference.

Three-dimensionally printed biphasic calcium phosphate blocks with different pore diameters for regeneration in rabbit calvarial defects.

BACKGROUND: Biphasic calcium phosphate (BCP) is the most frequently used synthetic bone substitutes, which comprises a combination of hydroxyapatite (HA) and beta-tricalcium phosphate (b-TCP). Thanks to the recent advances in digital dentistry and three-dimensional (3D) printing technology, synthetic block bone substitutes can be customized to fit individual defect morphologies. The diameter of the pores can influence the rate of bone formation and material resorption. The aim of this study was to compare three-dimensionally printed biphasic calcium phosphate (BCP) block bone substitutes with different pore diameters (0.8-, 1.0-, and 1.2- mm) for use in the regeneration of rabbit calvarial defects. METHODS: Four circular defects were formed on the calvaria of ten rabbits. Each defect was randomly allocated to one of the following study groups: (i) control group, (ii) 0.8-mm group, (iii) 1.0-mm group, and (iv) 1.2-mm group. All specimens were postoperatively harvested at 2 and 8 weeks, and radiographic and histomorphometric analyses were performed on the samples. RESULTS: Histologically, the BCP blocks remained unresorbed up to 8 weeks, and new bone formation occurred within the porous structures of the blocks. After the short healing period of 2 weeks, histomorphometric analysis indicated that new bone formation was significantly greater in the BCP groups compared with the control (p < 0.05). However, there were no significant differences between the groups with different pore diameters (p > 0.05). At 8 weeks, only the 1.0-mm group (3.42 ± 0.48 mm2, mean ± standard deviation) presented a significantly larger area of new bone compared with the control (2.26 ± 0.59 mm2) (p < 0.05). Among the BCP groups, the 1.0- and 1.2-mm groups exhibited significantly larger areas of new bone compared with the 0.8-mm group (3.42 ± 0.48 and 3.04 ± 0.66 vs 1.60 ± 0.70 mm2, respectively). CONCLUSIONS: Within the limitations of this study, the BCP block bone substitutes can be applied to bone defects for successful bone regeneration. Future studies should investigate more-challenging defect configurations prior to considering clinical applications.

Rheumatology expertise in advising immunocompromised healthcare workers: Insights from a survey of Australian rheumatologists.

BACKGROUND: Healthcare workers (HCW) with an inflammatory disease may be at increased risk of infections and their complications, however there is no evidence to guide specific measures to reduce the risk of immunocompromised HCW acquiring infection in the workplace. This cross-sectional study aimed to define the attitudes of rheumatologists and rheumatology trainees towards counselling immunocompromised healthcare workers about additional workplace precautions to minimise workplace risk of infection. METHODS: A cross-sectional survey was administered via Zoom poll during a webinar held in August 2020. Participants were Victorian and Tasmanian members of the Australian Rheumatology Association, which includes consultant rheumatologists and rheumatology trainees. Descriptive statistics were used to analyse survey responses. RESULTS: Of the 52 participants, 41 provided care to at least one immunocompromised healthcare worker. 21 out of 52 participants estimated that the majority of these patients sought their advice about infection risk in the workplace. The most common source of information for counselling patients on workplace infection risks were colleagues (38/50). Participants were most confident in providing information on influenza and hepatitis but less confident in providing information in tuberculosis, shingles and COVID-19. Most participants believed employers of immunocompromised HCW should play a role in providing advice on managing infection risks in the workplace. CONCLUSION: Our study reveals a level of uncertainty and discomfort amongst rheumatologists in providing recommendations to immunocompromised healthcare workers about managing their workplace risk of infection. We recommend the development of a framework to guide the clinician in making individualised recommendations for immunocompromised HCW.

Pharmacokinetics and Macrophage Inhibitory Cytokine-1 Pharmacodynamics of the Murine Double Minute 2 Inhibitor, Navtemadlin (KRT-232) in Fed and Fasted Healthy Subjects.

This single 60-mg dose, 4-period crossover study assessed the effect of food and formulation change on navtemadlin (KRT-232) pharmacokinetics (PK) and macrophage inhibitory cytokine-1 (MIC-1) pharmacodynamics. Healthy subjects (N = 30) were randomized to 3 treatment sequences, A: new tablet, fasted (reference, dosed twice); B: new tablet, 30 minutes after a high-fat meal (test 1); C: old tablet, fasted (test 2). PK/pharmacodynamic parameters were measured over 0 to 96 hours. Adverse events were mild without any discontinuations. No serious adverse events or deaths occurred. In treatment A, navtemadlin mean (coefficient of variation) maximum concentration (Cmax ) was 525 (66) ng/mL, at median time to maximum concentration (tmax ) of 2 hours. Mean (coefficient of variation) area under the plasma concentration-time curve from time 0 to time t (AUC0-t ) was 3392 (63.3) ng • h/mL, and arithmetic mean terminal half-life was 18.6 hours. Acyl glucuronide metabolite (M1)/navtemadlin AUC0-t ratio was 0.2, and urine excretion of navtemadlin was negligible. After a meal (B vs A), navtemadlin tmax was delayed by 1 hour. Geometric least squares means ratios (90%CI) for navtemadlin Cmax and AUC0-t were 102.7% (87.4-120.6) and 81.4% (76.2-86.9), respectively. Old vs new tablet fasted formulations (C vs A) had geometric least squares means ratios (90%CI) of 78.4% (72.0-85.3) for Cmax and 85.9% (80.5-91.7) for AUC0-t . MIC-1 Cmax and AUC were comparable across groups; tmax was delayed relative to navtemadlin tmax by ≈8 hours. Navtemadlin AUC0-t and MIC-1 AUC0-t correlated significantly. In conclusion, navtemadlin can be administered safely with or without food; the new formulation does not affect navtemadlin PK. The 60-mg navtemadlin dose elicited a reproducible and robust MIC-1 response that correlated well with navtemadlin exposure, indicating that murine double minute 2 target engagement leads to p53 activation.

Clinical practice guidelines for the management of atraumatic shoulder conditions: protocol for a systematic review.

INTRODUCTION: Shoulder conditions are a major cause of morbidity in the general population. Many clinical practice guidelines (CPGs) for shoulder conditions have been developed. Their purpose is to provide evidence-based recommendations to assist clinicians in providing optimal care to maximise patient outcomes. The aim of this systematic review is to identify, appraise, and compare the content and quality of CPGs for atraumatic shoulder conditions. METHODS AND ANALYSIS: CPGs for atraumatic shoulder conditions will be included provided they make recommendations about diagnosis and/or management, are identified by their authors as a guideline and are consistent with the Appraisal of Guidelines for Research and Evaluation (AGREE) II definition of a guideline. A systematic search of electronic databases, online guideline repositories and the websites of relevant professional societies will be conducted to identify eligible CPGs. Search terms relating to shoulder conditions (eg, 'adhesive capsulitis', 'rotator cuff' and 'bursitis') will be combined with a validated search filter for CPGs. Pairs of independent reviewers will determine eligibility of CPGs identified by the search. Quality appraisal of included CPGs will be performed using the AGREE II instrument. Recommendations from each CPG and how they were determined will be extracted and compared across similar CPGs. Results from this systematic review will be reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement. ETHICS AND DISSEMINATION: Ethical approval is not required for this systematic review. The results from this study will be published in a peer-reviewed journal and disseminated to professional societies that publish shoulder CPGs, clinical policy groups, clinicians, researchers and consumers. PROSPERO REGISTRATION NUMBER: CRD42020182723.

Phase 1 Concentration-QTc and Cardiac Safety Analysis of the MDM2 Antagonist KRT-232 in Patients With Advanced Solid Tumors, Multiple Myeloma, or Acute Myeloid Leukemia.

Cardiac safety and plasma concentration-QTc interval analyses were completed using data from 2 phase 1 studies of the selective mouse double minute chromosome 2 antagonist, KRT-232, in patients with solid tumors or multiple myeloma and acute myeloid leukemia (AML) who received KRT-232 doses of 15 to 480 mg once daily (QD; N = 130). A linear mixed-effects model related change from baseline Fridericia-corrected QT interval (ΔQTcF) to KRT-232 plasma concentrations. The final model included parameters for the intercept (with between-subject variability), KRT-232 concentration-ΔQTcF slope, and baseline QTcF effect on the intercept. Diagnostic plots indicated an adequate model fit. Mean (90% confidence interval) predicted ΔQTcF values at the maximum clinical dose (480 mg QD) were 2.04 (0.49-3.60) milliseconds for patients with solid tumors and 4.52 (2.35-6.69) milliseconds for patients with AML. Because the 90% confidence interval upper bound of the mean ΔQTcF was predicted to be below 10 milliseconds at doses up to 480 mg QD in patients with solid tumors, multiple myeloma, or AML, KRT-232 does not result in clinically meaningful QT prolongation at the doses currently under investigation in clinical trials. No significant cardiac safety concerns were identified at these doses.

EUS-guided confocal laser endomicroscopy: prediction of dysplasia in intraductal papillary mucinous neoplasms (with video).

BACKGROUND AND AIMS: Previous studies have validated EUS-guided needle-based confocal laser endomicroscopy (nCLE) diagnosis of intraductal papillary mucinous neoplasms (IPMNs). We sought to derive EUS-guided nCLE criteria for differentiating IPMNs with high-grade dysplasia/adenocarcinoma (HGD-Ca) from those with low/intermediate-grade dysplasia (LGD). METHODS: We performed a post hoc analysis of consecutive IPMNs with a definitive diagnosis from a prospective study evaluating EUS-guided nCLE in the diagnosis of pancreatic cysts. Three internal endosonographers reviewed all nCLE videos for the patients and identified potential discriminatory EUS-guided nCLE variables to differentiate HGD-Ca from LGD IPMNs (phase 1). Next, an interobserver agreement (IOA) analysis of variables from phase 1 was performed among 6 blinded external nCLE experts (phase 2). Last, 7 blinded nCLE-naïve observers underwent training and quantified variables with the highest IOA from phase 2 using dedicated software (phase 3). RESULTS: Among 26 IPMNs (HGD-Ca in 16), the reference standard was surgical histopathology in 24 and cytology confirmation of metastatic liver lesions in 2 patients. EUS-guided nCLE characteristics of increased papillary epithelial "width" and "darkness" were the most sensitive variables (90%; 95% confidence interval [CI], 84%-94% and 91%; 95% CI, 85%-95%, respectively) and accurate (85%; 95% CI, 78%-90% and 84%; 95% CI, 77%-89%, respectively) with substantial (κ = 0.61; 95% CI, 0.51-0.71) and moderate (κ = 0.55; 95% CI, 0.45-0.65) IOAs for detecting HGD-Ca, respectively (phase 2). Logistic regression models were fit for the outcome of HGD-Ca as predictor variables (phase 3). For papillary width (cut-off ≥50 µm), the sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) for detection of HGD-Ca were 87.5% (95% CI, 62%-99%), 100% (95% CI, 69%-100%), and 0.95, respectively. For papillary darkness (cut-off ≤90 pixel intensity), the sensitivity, specificity, and AUC for detection of HGD-Ca were 87.5% (95% CI, 62%-99%), 100% (95% CI, 69%-100%), and 0.90, respectively. CONCLUSIONS: In this derivation study, quantification of papillary epithelial width and darkness identified HGD-Ca in IPMNs with high accuracy. These quantifiable variables can be used in multicenter studies for risk stratification of IPMNs. (Clinical trial registration number: NCT02516488.).

Two novel adenoviruses found in Cave Myotis bats (Myotis velifer) in Oklahoma.

Bats are carriers of potentially zoonotic viruses, therefore it is crucial to identify viruses currently found in bats to better understand how they are maintained in bat populations and evaluate risks for transmission to other species. Adenoviruses have been previously detected in bats throughout the world, but sampling is still limited. In this study, 30 pooled-guano samples were collected from a cave roost of Myotis velifer in Oklahoma. A portion of the DNA polymerase gene from Adenoviridae was amplified successfully in 18 M. velifer samples; however, DNA sequence was obtained from only 6 of these M. velifer samples. One was collected in October 2016, one in March 2017, and 4 in July 2017. The October and March samples contained viral DNA that was 3.1% different from each other but 33% different than the novel viral sequence found in the July 2017 samples. Phylogenetic analysis of these fragments confirmed our isolates were from the genus Mastadenovirus and had genetic diversity ranging from 20 to 50% when compared to other bat adenoviruses.

High Frequency of Multiple Paternity in Eastern Red Bats, Lasiurus borealis, Based on Microsatellite Analysis.

Most species of bats give birth to only 1 pup each year, although Eastern red bats (Lasiurus borealis) can produce up to 5 pups per litter. Offspring in a single litter have been documented to be at different stages of development, suggesting that multiple paternity occurs. We tested the null hypothesis of genetic monogamy in red bats using 6 autosomal microsatellites and 1 X-linked microsatellite from 31 parent/offspring groups for a total of 128 bats. We sampled both pregnant females and mothers with pups that were obtained from bats submitted to departments of health in Oklahoma and Texas for rabies testing. Multiple paternity was assessed using a maximum-likelihood approach, hypothesis testing, and X-linked locus exclusion. The mean polymorphic information content of our markers was high (0.8819) and combined non-exclusion probability was low (0.00027). Results from the maximum-likelihood approach showed that 22 out of 31 (71%) parent/offspring groups consisted of half siblings, hypothesis testing rejected full sibship in 61% of parent/offspring groups, and X-linked locus exclusion suggested multiple paternity in at least 12 parent/offspring groups, rejecting our hypothesis of genetic monogamy. This frequency of multiple paternity is the highest reported thus far for any bat species. High levels of multiple paternity have the potential to impact interpretations of genetic estimates of effective population size in this species. Further, multiple paternity might be an adaptive strategy to allow for increased genetic variation and large litter size, which would be beneficial to a species threatened by population declines from wind turbines.

KRAS G12C NSCLC Models Are Sensitive to Direct Targeting of KRAS in Combination with PI3K Inhibition.

PURPOSE: KRAS-mutant lung cancers have been recalcitrant to treatments including those targeting the MAPK pathway. Covalent inhibitors of KRAS p.G12C allele allow for direct and specific inhibition of mutant KRAS in cancer cells. However, as for other targeted therapies, the therapeutic potential of these inhibitors can be impaired by intrinsic resistance mechanisms. Therefore, combination strategies are likely needed to improve efficacy.Experimental Design: To identify strategies to maximally leverage direct KRAS inhibition we defined the response of a panel of NSCLC models bearing the KRAS G12C-activating mutation in vitro and in vivo. We used a second-generation KRAS G12C inhibitor, ARS1620 with improved bioavailability over the first generation. We analyzed KRAS downstream effectors signaling to identify mechanisms underlying differential response. To identify candidate combination strategies, we performed a high-throughput drug screening across 112 drugs in combination with ARS1620. We validated the top hits in vitro and in vivo including patient-derived xenograft models. RESULTS: Response to direct KRAS G12C inhibition was heterogeneous across models. Adaptive resistance mechanisms involving reactivation of MAPK pathway and failure to induce PI3K-AKT pathway inactivation were identified as likely resistance events. We identified several model-specific effective combinations as well as a broad-sensitizing effect of PI3K-AKT-mTOR pathway inhibitors. The G12Ci+PI3Ki combination was effective in vitro and in vivo on models resistant to single-agent ARS1620 including patient-derived xenografts models. CONCLUSIONS: Our findings suggest that signaling adaptation can in some instances limit the efficacy of ARS1620 but combination with PI3K inhibitors can overcome this resistance.

SHP2 inhibition restores sensitivity in ALK-rearranged non-small-cell lung cancer resistant to ALK inhibitors.

Most anaplastic lymphoma kinase (ALK)-rearranged non-small-cell lung tumors initially respond to small-molecule ALK inhibitors, but drug resistance often develops. Of tumors that develop resistance to highly potent second-generation ALK inhibitors, approximately half harbor resistance mutations in ALK, while the other half have other mechanisms underlying resistance. Members of the latter group often have activation of at least one of several different tyrosine kinases driving resistance. Such tumors are not expected to respond to lorlatinib-a third-generation inhibitor targeting ALK that is able to overcome all clinically identified resistant mutations in ALK-and further therapeutic options are limited. Herein, we deployed a shRNA screen of 1,000 genes in multiple ALK-inhibitor-resistant patient-derived cells (PDCs) to discover those that confer sensitivity to ALK inhibition. This approach identified SHP2, a nonreceptor protein tyrosine phosphatase, as a common targetable resistance node in multiple PDCs. SHP2 provides a parallel survival input downstream of multiple tyrosine kinases that promote resistance to ALK inhibitors. Treatment with SHP099, the recently discovered small-molecule inhibitor of SHP2, in combination with the ALK tyrosine kinase inhibitor (TKI) ceritinib halted the growth of resistant PDCs through preventing compensatory RAS and ERK1 and ERK2 (ERK1/2) reactivation. These findings suggest that combined ALK and SHP2 inhibition may be a promising therapeutic strategy for resistant cancers driven by several different ALK-independent mechanisms underlying resistance.

Effect of mono- and diglycerides on the digestion and absorption of lutein in lymph fistula rats.

Breast milk lutein is better absorbed by infants than lutein delivered in infant formula. Therefore, we wanted to better understand the possible absorption differences of lutein in breast milk vs. that in infant formula by determining its bioavailability after gastric administration and whether the intestinal absorption of lutein can be improved by using new delivery vehicles. Study 1 compared the intestinal uptake,and the lymphatic and portal transport of lutein in conscious lymph fistula rats. Four groups of lymph- and portal vein-cannulated rats ( n = 8-10/group) were randomized to receive via gastric tube increasing doses (10, 20, 40, or 80 mg/kg) of 20% lutein in safflower oil (SO) suspension to assess whether there was a saturable level of lutein that could be absorbed and transported in lymph. Aliquots of hourly portal blood and lymph were taken for lutein and zeaxanthin analyses. The dose-response study showed that 20 mg/kg lutein was the saturable level of lymphatic lutein absorption with no lutein detected in portal circulation at any dosage level tested. Study 2 randomized five groups of lymph fistula rats ( n = 4-9/group) to receive 20 mg/kg lutein from either lutein in SO or lutein in four different mono- and diglyceride oils (MDGs). Gastric infusion of lutein suspended in MDG (20 mg/kg) significantly improved (71-211%, P < 0.05) lymphatic lutein output 2-6 h after lipid feeding vs. lutein in SO. Lymphatic zeaxanthin (10% of the lutein fed mixture) transport in both Study 1 and Study 2 followed that of lutein. We conclude that a mixture of MDGs helps solubilize lutein and facilitate gastrointestinal micelle formation, thus improving lymphatic lutein absorption compared with triglyceride oils. NEW & NOTEWORTHY This paper describes how lutein is digested and absorbed by the gastrointestinal tract by using the conscious lymph fistula rat model. Our dose-response study showed that absorption and lymphatic transport of lutein is a saturable process with no lutein detected in portal circulation at any dosage level tested. Our paper also provides insight into how this process can be improved by modifying the typical lipid mixtures carrying the lutein.