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The colonization of Staphylococcus aureus, especially methicillin-resistant S. aureus (MRSA), has a detrimental effect on the respiratory care of pediatric patients with cystic fibrosis (CF). In addition to being resistant to multiple antibiotics, S. aureus also has the ability to form biofilms, which makes the infection more difficult to treat and eradicate. In this study, we examined the ability of S. aureus strains isolated from pediatric patients with CF to form biofilms. We screened a transposon mutant library of MRSA and identified a putative cobalt transporter ATP binding domain (cbiO) that is required for biofilm formation. We discovered that deleting cbiO creating a cbiO null mutant in CFSa36 (an MRSA strain isolated from a patient with cystic fibrosis) significantly hinders the ability of CFSa36 to form biofilm. The complementation of cbiO restored the ability of the cbiO deletion mutant to generate biofilm. Interestingly, we revealed that incorporating extra copper ions to the chemically defined medium (CDM) complemented the function of cbiO for biofilm formation in a dose-dependent manner, while the addition of extra iron ions in CDM enhanced the effect of cbiO null mutation on biofilm formation. In addition, neither the addition of certain extra amounts of copper ions nor iron ions in CDM had an impact on bacterial growth. Taken together, our findings suggest that cbiO mediates biofilm formation by affecting the transportation of copper ions in the MRSA CFSa36 strain. This study provides new insights into the molecular basis of biofilm formation by S. aureus.

Abstract Background Intracranial aneurysm (IA) has been associated with bicuspid aortic valve (BAV) with prevalence of 6–10% which has led some to recommend routine surveillance for IA in BAV patients. Higher incidence of IA in BAV could signal towards systemic arteriopathy beyond the thoracic aorta. With CoA as an independent risk factor for IA formation, it is currently uncertain if the association between IA and BAV reflects the association of BAV and CoA, or the result of BAV-related systemic arterial changes. Purpose Despite this association, 2 small studies suggest no increased risk of the most important patient outcome: aneurysmal sub-arachnoid hemorrhage (aSAH). Our primary aim was identifying the prevalence of BAV in aSAH patients and compare it with that of a control group without aSAH. Secondary aims included neurologic outcomes of aSAH and anatomical characteristics of IA in BAV, and final disposition and outcome. Methods Patients (>18 years age) with an accurate diagnosis of aSAH and at least one echocardiogram in the system between January 2000-December 2019 were identified from a prospectively maintained registry of aSAH admissions. Controls, without a diagnosis of SAH ever, were age- and gender-matched (1:2 cases:controls). BAV prevalence was echocardiographically-confirmed in all patients. Severity of aSAH was categorized using the modified Fisher (mFisher) and the World Federation of Neurological Scale (WFNS). Results A total of 488 aSAH cases and 990 controls were included in the final analysis with confirmed aortic valve status. The prevalence of BAV in aSAH patients was 1.2% (6/488) vs 3.5% (35/990) in controls, p=0.01. None of the aSAH cases were noted to have CoA, whereas 3 (0.3%; p=0.12) control patients had presence of both BAV and CoA. Within aSAH patients, BAV+aSAH were noted to be younger than tricuspid aortic valve (TAV)+aSAH (56±11 vs 68±14; p=0.03). Aneurysm size was smaller in the BAV+aSAH group (5±2 vs 7±4 in TAV+aSAH; p=0.31). The severity of the bleed was lesser in BAV+aSAH than TAV+aSAH (mFisher grade >2 50% vs 74%; p=0.19, WFNS grade >3 17% vs 36%; p=0.43) which is clinically significant. The BAV+aSAH group had higher disposition rate to home (67% vs 39%; p=0.21) with no difference in in-hospital mortality rates (17% vs 18%; p=0.93). BAV had lower odds on univariate and multivariate analyses adjusted for age/sex/body mass index (OR 0.33 [CI 0.14–0.81]; p=0.01, OR 0.23 [CI 0.08–0.65]; p=0.01) of presenting with aSAH. Conclusion Within a large prospective registry with accurate aSAH diagnoses, we found 3-times lower prevalence of echocardiographically-confirmed BAV as compared to non-aSAH controls. We observed 3-times higher prevalence of BAV in controls than among aSAH cases. In addition, size of intracranial aneurysms was clinically smaller in BAV patients, and the severity of SAH was significantly lesser in BAV from a clinical standpoint. Our findings argue against routine surveillance for IA in BAV patients without CoA. Funding Acknowledgement Type of funding sources: None.

Understanding the pathogenesis and molecular biology of malignant lymphomas is challenging, given the complex nature and incongruity of these disorders. The classification of lymphoma is continually evolving to account for advances in clinical, pathological, molecular biology and cytogenetic aspects, which impact our understanding of these disorders. The latest fourth edition of the WHO classification of lymphoid malignancies was released in 2016 to account for these changes. Additionally, unlike B-cell lymphomas (BCL), T-cell lymphomas (TCL) are uncommon, and may be sporadically experienced in clinical practice. These disorders are rare, thus early diagnosis is challenging for both physicians and radiologists, owing to the overlap in clinical and imaging features with other, more common disorders. We aim to discuss some rare variants of T-cell lymphomas, including clinicopathologic and imaging features, as well as to give a glimpse of the updates contained within the new 2016 WHO classification.

Abstract Background. Quantitative radiomic features of medical images could provide clinical significance in assisting decision-making, but the existing feature selection and modeling methods are usually parameter-dependent. We aim to develop and validate a generalized radiomic method applicable to a variety of clinical outcomes. Methods and materials. A generalized methodology for radiomic feature selection and modeling (‘GRFM’ for short), including two-step feature selection and logistic regression, was proposed for studying clinical outcomes correlations. The two-step feature selection consists of Pearson correlation analysis followed by a sequential forward floating selection algorithm to identify robust feature subsets. We also applied an adaptive searching strategy to systematically determine globally optimal parameters, rather than relying on preset parameters. The area under the receiver operating characteristic curve (AUC) was used to evaluate the performance of three outcomes: lymph node metastasis of gastric cancer (GC), the five-year survival status of high-grade osteosarcoma (HOS), and the pathological grade of pancreatic neuroendocrine tumors (pNETs). Results. The optimal Pearson thresholds were 0.85, 0.80 and 0.75, and the optimal feature numbers were 11, 14 and 8 in GC, HOS and pNETs, respectively. The AUC values of the three predictive models combined with the corresponding parameters were 0.9017 versus 0.9026, 0.7652 versus 0.7113, and 0.8438 versus 0.8212 for the training and validation cohorts, showing promissing generality and classifier performance . Conclusion. The proposed method was helpful in predicting different clinical outcomes, and has potential application as a general and noninvasive prediction tool to guide clinical decision-making in various cancer sites.

Abstract KRAS-activating mutations are oncogenic drivers and are correlated with radioresistance of multiple cancers, including colorectal cancer, but the underlying precise molecular mechanisms remain elusive. Herein we model the radiosensitivity of isogenic HCT116 and SW48 colorectal cancer cell lines bearing wild-type or various mutant KRAS isoforms. We demonstrate that KRAS mutations indeed lead to radioresistance accompanied by reduced radiotherapy-induced mitotic catastrophe and an accelerated release from G2/M arrest. Moreover, KRAS mutations result in increased DNA damage response and upregulation of 53BP1 with associated increased non-homologous end-joining (NHEJ) repair. Remarkably, KRAS mutations lead to activation of NRF2 antioxidant signaling to increase 53BP1 gene transcription. Furthermore, genetic silencing or pharmacological inhibition of KRAS, NRF2 or 53BP1 attenuates KRAS mutation-induced radioresistance, especially in G1 phase cells. These findings reveal an important role for a KRAS-induced NRF2-53BP1 axis in the DNA repair and survival of KRAS-mutant tumor cells after radiotherapy, and indicate that targeting NRF2, 53BP1 or NHEJ may represent novel strategies to selectively abrogate KRAS mutation-mediated radioresistance.

LINKED CONTENTThis article is linked to Wijarnpreecha et al and Huang & Nguyen papers. To view these articles, visit https://doi.org/10.1111/apt.16590 and https://doi.org/10.1111/apt.16576