Role of Bß1 overexpression in the pathogenesis of SCA12.

BACKGROUND: Spinocerebellar ataxia type 12 (SCA12) is a neurodegenerative disease caused by a CAG/CTG repeat expansion at the PPP2R2B locus. OBJECTIVE: We investigated how the CAG repeat expansion within the PPP2R2B 7B7D transcript influences the expression of Bß1 and a potential protein containing a long polyserine tract. METHODS: Transcript and protein expression were measured using quantitative PCR (qPCR) Role of Bß1 overexpression in the pathogenesis of SCA12 and Western blot, respectively, in an SK-N-MC cell model that overexpresses the full-length PPP2R2B 7B7D transcript. The apoptotic effect of a protein containing a long polyserine tract on SK-N-MC cells was evaluated using caspase 3/7 activity. RESULTS: The CAG repeat expansion increases the expression of the PPP2R2B 7B7D transcript, as well as Bß1 protein, in an SK-N-MC cell model in which the full-length PPP2R2B 7B7D transcript is overexpressed. The CAG repeat expansion within the 7B7D transcript is translated into a long polyserine tract that triggers apoptosis in SK-N-MC cells. CONCLUSIONS: The SCA12 mutation leads to overexpression of PPP2R2B Bß1 and to expression of a protein containing a long polyserine tract; both these effects potentially contribute to SCA12 pathogenesis. © 2024 International Parkinson and Movement Disorder Society.

Generation of a human induced pluripotent stem cell line JHUi004-A with heterozygous mutation for spinocerebellar ataxia type 12 using genome editing.

Spinocerebellar ataxia type 12 (SCA12) is caused by a CAG expansion mutation in PPP2R2B, a gene encoding brain-specific regulatory units of protein phosphatase 2A (PP2A); while normal alleles carry 4 to 31 triplets, the disease alleles carry 43 to 78 triplets. Here, by CRISPR/Cas9n genome editing, we have generated a human heterozygous SCA12 iPSC line with 73 triplets for the mutant allele. The heterozygous SCA12 iPSCs have normal karyotype, express pluripotency markers and are able to differentiate into the three germ layers.

Reevaluating the FDA's warning against the use of probiotics in preterm neonates: A societal statement by ESPGHAN and EFCNI.

The recent advisory issued by the United States Food and Drug Administration, cautioning against the routine administration of probiotics in preterm neonates, has sparked a lively debate within the scientific community. This commentary presents a perspective from members of the Special Interest Group on Gut Microbiota and Modifications within the European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) and other authors who contributed to the ESPGHAN position paper on probiotics for preterm infants, as well as representatives from the European Foundation for the Care of Newborn Infants. We advocate for a more nuanced and supportive approach to the use of certain probiotics in this vulnerable population, balancing the demonstrated benefits and risks.

Characterizing the Suture Pullout Force for Human Small Bowel.

Performing a small bowel anastomosis, or reconnecting small bowel segments, remains a core competency and critical step for the successful surgical management of numerous bowel and urinary conditions. As surgical education and technology moves toward improving patient outcomes through automation and increasing training opportunities, a detailed characterization of the interventional biomechanical properties of the human bowel is important. This is especially true due to the prevalence of anastomotic leakage as a frequent (3.02%) postoperative complication of small bowel anastomoses. This study aims to characterize the forces required for a suture to tear through human small bowel (suture pullout force, SPOF), while analyzing how these forces are affected by tissue orientation, suture material, suture size, and donor demographics. 803 tests were performed on 35 human small bowel specimens. A uni-axial test frame was used to tension sutures looped through 10 × 20 mm rectangular bowel samples to tissue failure. The mean SPOF of the small bowel was 4.62±1.40 N. We found no significant effect of tissue orientation (p = 0.083), suture material (p = 0.681), suture size (p = 0.131), age (p = 0.158), sex (p = .083), or body mass index (BMI) (p = 0.100) on SPOF. To our knowledge, this is the first study reporting human small bowel SPOF. Little research has been published about procedure-specific data on human small bowel. Filling this gap in research will inform the design of more accurate human bowel synthetic models and provide an accurate baseline for training and clinical applications.

Bidirectional Transcription at the PPP2R2B Gene Locus in Spinocerebellar Ataxia Type 12.

BACKGROUND: Spinocerebellar ataxia type 12 (SCA12) is a neurodegenerative disease caused by expansion of a CAG repeat in the PPP2R2B gene. OBJECTIVE: In this study, we tested the hypothesis that the PPP2R2B antisense (PPP2R2B-AS1) transcript containing a CUG repeat is expressed and contributes to SCA12 pathogenesis. METHODS: Expression of PPP2R2B-AS1 transcript was detected in SCA12 human induced pluripotent stem cells (iPSCs), iPSC-derived NGN2 neurons, and SCA12 knock-in mouse brains using strand-specific reverse transcription polymerase chain reaction. The tendency of expanded PPP2R2B-AS1 (expPPP2R2B-AS1) RNA to form foci, a marker of toxic processes involving mutant RNAs, was examined in SCA12 cell models by fluorescence in situ hybridization. The apoptotic effect of expPPP2R2B-AS1 transcripts on SK-N-MC neuroblastoma cells was evaluated by caspase 3/7 activity. Western blot was used to examine the expression of repeat associated non-ATG-initiated translation of expPPP2R2B-AS1 transcript in SK-N-MC cells. RESULTS: The repeat region in the PPP2R2B gene locus is bidirectionally transcribed in SCA12 iPSCs, iPSC-derived NGN2 neurons, and SCA12 mouse brains. Transfected expPPP2R2B-AS1 transcripts induce apoptosis in SK-N-MC cells, and the apoptotic effect may be mediated, at least in part, by the RNA secondary structure. The expPPP2R2B-AS1 transcripts form CUG RNA foci in SK-N-MC cells. expPPP2R2B-AS1 transcript is translated in the alanine open reading frame (ORF) via repeat-associated non-ATG translation, which is diminished by single-nucleotide interruptions within the CUG repeat and MBNL1 overexpression. CONCLUSIONS: These findings suggest that PPP2R2B-AS1 contributes to SCA12 pathogenesis and may therefore provide a novel therapeutic target for the disease. © 2023 International Parkinson and Movement Disorder Society.

Accuracy of radiographic measurements of fracture-induced deformity in the distal radius.

Background: Management of the distal radius fracture (DRF) is to some extent based on radiographic characterization of fracture displacement. It remains unclear, however, if the measurements used to quantify displacement are accurate. Purpose: To quantify accuracy of two radiographic measurements: dorsal/volar tilt and fracture compression, measured indirectly as ulnar variance (UV), using radiostereometric analyses (RSA) as reference standard. Material and Methods: Twenty-one fresh frozen non-fractured human cadaveric forearms (right = 11, left = 10) were thawed and eligible for inclusion. The forearms were mounted on a custom made platform that allowed for controlled forearm rotation, and they underwent two rounds of imaging (both rounds consisted of RSA and radiographs). In round one, the non-fractured forearms were radiographed. In round two, artificial DRF´s with compression and dorsal angulation were created and imaging procedures repeated. Change in tilt and UV between the non-fractured and later fractured forearms was defined as fracture-induced deformity. Deformity was measured radiographically and additionally calculated using RSA. Bland Altman analyses were used to estimate agreement between radiographically measured, and RSA calculated, fracture-induced deformity. Results: Our results indicated that radiographs underestimate the amount of fracture-induced deformity. Mean measured differences (bias) in dorsal tilt deformity between radiographs and RSA were -2.5° for both observers. The corresponding values for UV were -1.4 mm and -1.5 mm. Conclusion: Quantifying fracture-induced deformity on radiographs underestimated the actual deformity when compared to RSA calculated deformity. These findings suggest that clinicians, at least in part, base fracture management and potentially corrective surgery on inaccurate measurements.

Listeria monocytogenes requires DHNA-dependent intracellular redox homeostasis facilitated by Ndh2 for survival and virulence.

Listeria monocytogenes is a remarkably well-adapted facultative intracellular pathogen that can thrive in a wide range of ecological niches. L. monocytogenes maximizes its ability to generate energy from diverse carbon sources using a respiro-fermentative metabolism that can function under both aerobic and anaerobic conditions. Cellular respiration maintains redox homeostasis by regenerating NAD+ while also generating a proton motive force. The end products of the menaquinone (MK) biosynthesis pathway are essential to drive both aerobic and anaerobic cellular respirations. We previously demonstrated that intermediates in the MK biosynthesis pathway, notably 1,4-dihydroxy-2-naphthoate (DHNA), are required for the survival and virulence of L. monocytogenes independent of their role in respiration. Furthermore, we found that restoration of NAD+/NADH ratio through expression of water-forming NADH oxidase could rescue phenotypes associated with DHNA deficiency. Here, we extend these findings to demonstrate that endogenous production or direct supplementation of DHNA restored both the cellular redox homeostasis and metabolic output of fermentation in L. monocytogenes. Furthermore, exogenous supplementation of DHNA rescues the in vitro growth and ex vivo virulence of L. monocytogenes DHNA-deficient mutants. Finally, we demonstrate that exogenous DHNA restores redox balance in L. monocytogenes specifically through the recently annotated NADH dehydrogenase Ndh2, independent of its role in the extracellular electron transport pathway. These data suggest that the production of DHNA may represent an additional layer of metabolic adaptability by L. monocytogenes to drive energy metabolism in the absence of respiration-favorable conditions.

Uneven Between-Hospital Distribution of Patient-Related Risk Factors for Adverse Outcomes of Colorectal Cancer Treatment: A Population-Based Register Study.

Purpose: The purpose of this study was to elucidate between-hospital variation in the prevalence at the time of diagnosis of patient-related risk factors for adverse outcomes of colorectal cancer (CRC) treatment. Patients and Methods: A register-based national cohort of 44,471 patients diagnosed with CRC and registered in the Danish Colorectal Cancer Group database in 2009-2018 was included in the study. Patient-related risk factors present at diagnosis were collected from national Danish registers within the areas of demography, lifestyle factors, comorbidity, participation in screening, disease-related factors and socioeconomic factors. Prediction models of short-term postoperative outcomes and mortality were modelled to examine the potential aggregated impact of patient-related risk factors on outcomes, and variations between hospitals were examined. Results: The most conspicuous variations found were for old age (75+ years), ranging from 31% (95% confidence interval (95% CI): 29-33%) to 46% (95% CI: 43-48%), Union for International Cancer Control Stage I ranging from 12% (95% CI: 10-14%) to 21% (95% CI: 19-22%), Stage IV ranging from 23% (95% CI: 21-25%) to 35% (95% CI: 34-37%) and American Society of Anesthesiologists score ≥III ranging from 18% (95% CI: 16-19%) to 40% (95% CI: 37-43%). Clinically significant variations were found in predicted probability of 30-day surgical complications which varied from 17% (95% CI: 16-17%) to 23% (95% CI: 22-23%) and 90-day postoperative mortality which varied between 3.2% (95% CI: 3-3.4%) and 5.5% (95% CI: 4.9-6%). Conclusion: Marked variation in the prevalence of patient-related risk factors for adverse outcomes of colorectal cancer treatment exists between hospitals in Denmark. It seems reasonable to take these differences into account when comparing outcomes between hospitals.

The Plasmodium falciparum apicoplast cysteine desulfurase provides sulfur for both iron-sulfur cluster assembly and tRNA modification.

Iron-sulfur clusters (FeS) are ancient and ubiquitous protein cofactors that play fundamental roles in many aspects of cell biology. These cofactors cannot be scavenged or trafficked within a cell and thus must be synthesized in any subcellular compartment where they are required. We examined the FeS synthesis proteins found in the relict plastid organelle, called the apicoplast, of the human malaria parasite Plasmodium falciparum. Using a chemical bypass method, we deleted four of the FeS pathway proteins involved in sulfur acquisition and cluster assembly and demonstrated that they are all essential for parasite survival. However, the effect that these deletions had on the apicoplast organelle differed. Deletion of the cysteine desulfurase SufS led to disruption of the apicoplast organelle and loss of the organellar genome, whereas the other deletions did not affect organelle maintenance. Ultimately, we discovered that the requirement of SufS for organelle maintenance is not driven by its role in FeS biosynthesis, but rather, by its function in generating sulfur for use by MnmA, a tRNA modifying enzyme that we localized to the apicoplast. Complementation of MnmA and SufS activity with a bacterial MnmA and its cognate cysteine desulfurase strongly suggests that the parasite SufS provides sulfur for both FeS biosynthesis and tRNA modification in the apicoplast. The dual role of parasite SufS is likely to be found in other plastid-containing organisms and highlights the central role of this enzyme in plastid biology.

Bidirectional transcription at the PPP2R2B gene locus in spinocerebellar ataxia type 12.

OBJECTIVE: Spinocerebellar ataxia type 12 (SCA12) is a neurodegenerative disease caused by expansion of a CAG repeat in the PPP2R2B gene . Here we tested the hypothesis that the PPP2R2B antisense ( PPP2R2B-AS1 ) transcript containing a CUG repeat is expressed and contributes to SCA12 pathogenesis. METHODS: Expression of PPP2R2B-AS1 transcript was detected in SCA12 human induced pluripotent stem cells (iPSCs), iPSC-derived NGN2 neurons, and SCA12 knock-in mouse brains using strand-specific RT-PCR (SS-RT-PCR). The tendency of expanded PPP2R2B-AS1 ( expPPP2R2B-AS1 ) RNA to form foci, a marker of toxic processes involving mutant RNAs, was examined in SCA12 cell models by fluorescence in situ hybridization. The toxic effect of expPPP2R2B-AS1 transcripts on SK-N-MC neuroblastoma cells was evaluated by caspase 3/7 activity. Western blot was used to examine the expression of repeat associated non-ATG-initiated (RAN) translation of expPPP2R2B-AS1 transcript in SK-N-MC cells. RESULTS: The repeat region in PPP2R2B gene locus is bidirectionally transcribed in SCA12 iPSCs, iPSC-derived NGN2 neurons, and SCA12 mouse brains. Transfected expPPP2R2B-AS1 transcripts are toxic to SK-N-MC cells, and the toxicity may be mediated, at least in part, by the RNA secondary structure. The expPPP2R2B-AS1 transcripts form CUG RNA foci in SK-N-MC cells. expPPP2R2B-AS1 transcript is translated in the Alanine ORF via repeat-associated non-ATG (RAN) translation, which is diminished by single nucleotide interruptions within the CUG repeat, and MBNL1 overexpression. INTERPRETATION: These findings suggest that PPP2R2B-AS1 contributes to SCA12 pathogenesis, and may therefore provide a novel therapeutic target for the disease.

Listeria monocytogenes GlmR Is an Accessory Uridyltransferase Essential for Cytosolic Survival and Virulence.

The cytosol of eukaryotic host cells is an intrinsically hostile environment for bacteria. Understanding how cytosolic pathogens adapt to and survive in the cytosol is critical to developing novel therapeutic interventions against these pathogens. The cytosolic pathogen Listeria monocytogenes requires glmR (previously known as yvcK), a gene of unknown function, for resistance to cell-wall stress, cytosolic survival, inflammasome avoidance, and, ultimately, virulence in vivo. In this study, a genetic suppressor screen revealed that blocking utilization of UDP N-acetylglucosamine (UDP-GlcNAc) by a nonessential wall teichoic acid decoration pathway restored resistance to lysozyme and partially restored virulence of ΔglmR mutants. In parallel, metabolomic analysis revealed that ΔglmR mutants are impaired in the production of UDP-GlcNAc, an essential peptidoglycan and wall teichoic acid (WTA) precursor. We next demonstrated that purified GlmR can directly catalyze the synthesis of UDP-GlcNAc from GlcNAc-1P and UTP, suggesting that it is an accessory uridyltransferase. Biochemical analysis of GlmR orthologues suggests that uridyltransferase activity is conserved. Finally, mutational analysis resulting in a GlmR mutant with impaired catalytic activity demonstrated that uridyltransferase activity was essential to facilitate cell-wall stress responses and virulence in vivo. Taken together, these studies indicate that GlmR is an evolutionary conserved accessory uridyltransferase required for cytosolic survival and virulence of L. monocytogenes. IMPORTANCE Bacterial pathogens must adapt to their host environment in order to cause disease. The cytosolic bacterial pathogen Listeria monocytogenes requires a highly conserved protein of unknown function, GlmR (previously known as YvcK), to survive in the host cytosol. GlmR is important for resistance to some cell-wall stresses and is essential for virulence. The ΔglmR mutant is deficient in production of an essential cell-wall metabolite, UDP-GlcNAc, and suppressors that increase metabolite levels also restore virulence. Purified GlmR can directly catalyze the synthesis of UDP-GlcNAc, and this enzymatic activity is conserved in both Bacillus subtilis and Staphylococcus aureus. These results highlight the importance of accessory cell wall metabolism enzymes in responding to cell-wall stress in a variety of Gram-positive bacteria.

Listeria monocytogenes requires DHNA-dependent intracellular redox homeostasis facilitated by Ndh2 for survival and virulence.

Listeria monocytogenes is a remarkably well-adapted facultative intracellular pathogen that can thrive in a wide range of ecological niches. L. monocytogenes maximizes its ability to generate energy from diverse carbon sources using a respiro-fermentative metabolism that can function under both aerobic and anaerobic conditions. Cellular respiration maintains redox homeostasis by regenerating NAD + while also generating a proton motive force (PMF). The end products of the menaquinone (MK) biosynthesis pathway are essential to drive both aerobic and anaerobic cellular respiration. We previously demonstrated that intermediates in the MK biosynthesis pathway, notably 1,4-dihydroxy-2-naphthoate (DHNA), are required for the survival and virulence of L. monocytogenes independent of their role in respiration. Furthermore, we found that restoration of NAD + /NADH ratio through expression of water-forming NADH oxidase (NOX) could rescue phenotypes associated with DHNA deficiency. Here we extend these findings to demonstrate that endogenous production or direct supplementation of DHNA restored both the cellular redox homeostasis and metabolic output of fermentation in L. monocytogenes . Further, exogenous supplementation of DHNA rescues the in vitro growth and ex vivo virulence of L. monocytogenes DHNA-deficient mutants. Finally, we demonstrate that exogenous DHNA restores redox balance in L. monocytogenes specifically through the recently annotated NADH dehydrogenase Ndh2, independent of the extracellular electron transport (EET) pathway. These data suggest that the production of DHNA may represent an additional layer of metabolic adaptability by L. monocytogenes to drive energy metabolism in the absence of respiration-favorable conditions.

Anastomotic perfusion assessment with indocyanine green in robot-assisted low-anterior resection, a multicenter study of interobserver variation.

BACKGROUND: Securing sufficient blood perfusion to the anastomotic area after low-anterior resection is a crucial factor in preventing anastomotic leakage (AL). Intra-operative indocyanine green fluorescent imaging (ICG-FI) has been suggested as a tool to assess perfusion. However, knowledge of inter-observer variation among surgeons in the interpretation of ICG-FI is sparse. Our primary objective was to evaluate inter-observer variation among surgeons in the interpretation of bowel blood-perfusion assessed visually by ICG-FI. Our secondary objective was to compare the results both from the visual assessment of ICG and from computer-based quantitative analyses of ICG-FI between patients with and without the development of AL. METHOD: A multicenter study, including patients undergoing robot-assisted low anterior resection with stapled anastomosis. ICG-FI was evaluated visually by the surgeon intra-operatively. Postoperatively, recorded videos were anonymized and exchanged between centers for inter-observer evaluation. Time to visibility (TTV), time to maximum visibility (TMV), and time to wash-out (TWO) were visually assessed. In addition, the ICG-FI video-recordings were analyzed using validated pixel analysis software to quantify blood perfusion. RESULTS: Fifty-five patients were included, and five developed clinical AL. Bland-Altman plots (BA plots) demonstrated wide inter-observer variation for visually assessed fluorescence on all parameters (TTV, TMV, and TWO). Comparing leak-group with no-leak group, we found no significant differences for TTV: Hazard Ratio; HR = 0.82 (CI 0.32; 2.08), TMV: HR = 0.62 (CI 0.24; 1.59), or TWO: HR = 1.11 (CI 0.40; 3.11). In the quantitative pixel analysis, a lower slope of the fluorescence time-curve was found in patients with a subsequent leak: median 0.08 (0.07;0.10) compared with non-leak patients: median 0.13 (0.10;0.17) (p = 0.04). CONCLUSION: The surgeon's visual assessment of the ICG-FI demonstrated wide inter-observer variation, there were no differences between patients with and without AL. However, quantitative pixel analysis showed a significant difference between groups. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04766060.

Validity and reliability of the Rosacea Area and Severity Index: A novel scoring system for clinical assessment of rosacea severity.

BACKGROUND: Rosacea is a common chronic inflammatory facial skin disorder. Standardized evaluation of the severity and extent of rosacea is important for baseline assessment and treatment effect. The currently used Investigator's Global Assessment (IGA) is unspecific and fails to consider subtypes/phenotypes of rosacea and area involvement. The Rosacea Area and Severity Index (RASI) was developed to give a more nuanced evaluation of rosacea features in four facial skin areas adjusted to the relative importance of each area of the face to obtain an overall severity score. OBJECTIVES: To validate RASI against the IGA and to assess the inter- and intraobserver reliability for RASI. METHODS: Sixteen dermatologists evaluated photographs of 60 adult patients with rosacea (3 photographs per patient, one from the front and one from each side). IGA and RASI scores were performed for interobserver reliability assessment. To determine intraobserver reliability, 14 dermatologists evaluated 10 other patients twice with at least 1 week interval. RESULTS: The IGA and RASI correlated well (Spearman correlation coefficient (SCC) = 0.75, 95% confidence interval (CI) = 0.72-0.78). Interobserver reliability was moderate for RASI and poor to moderate for IGA. Reliability was strongest for rhinophyma, followed by papules/pustules and erythema, and rather weak for telangiectasia. For area scores, interobserver reliability was strongest for cheeks, followed by nose, chin and forehead. We found a moderate-to-strong intraobserver agreement both for IGA and RASI. CONCLUSIONS: We have designed a new practical tool to examine clinical severity of rosacea. RASI proved simple and reliable in scoring clinical severity of rosacea with an agreement comparable to the currently used IGA although RASI will provide a more nuanced view of the current rosacea extent and severity. We suggest that RASI is used in the daily clinical setting as well as in clinical studies assessing the efficacy of rosacea therapies.

An mTORC1-mediated negative feedback loop constrains amino acid-induced FLCN-Rag activation in renal cells with TSC2 loss.

The mechanistic target of rapamycin complex 1 (mTORC1) integrates inputs from growth factors and nutrients, but how mTORC1 autoregulates its activity remains unclear. The MiT/TFE transcription factors are phosphorylated and inactivated by mTORC1 following lysosomal recruitment by RagC/D GTPases in response to amino acid stimulation. We find that starvation-induced lysosomal localization of the RagC/D GAP complex, FLCN:FNIP2, is markedly impaired in a mTORC1-sensitive manner in renal cells with TSC2 loss, resulting in unexpected TFEB hypophosphorylation and activation upon feeding. TFEB phosphorylation in TSC2-null renal cells is partially restored by destabilization of the lysosomal folliculin complex (LFC) induced by FLCN mutants and is fully rescued by forced lysosomal localization of the FLCN:FNIP2 dimer. Our data indicate that a negative feedback loop constrains amino acid-induced, FLCN:FNIP2-mediated RagC activity in renal cells with constitutive mTORC1 signaling, and the resulting MiT/TFE hyperactivation may drive oncogenesis with loss of the TSC2 tumor suppressor.

Massively parallel genomic perturbations with multi-target CRISPR interrogates Cas9 activity and DNA repair at endogenous sites.

Here we present an approach that combines a clustered regularly interspaced short palindromic repeats (CRISPR) system that simultaneously targets hundreds of epigenetically diverse endogenous genomic sites with high-throughput sequencing to measure Cas9 dynamics and cellular responses at scale. This massive multiplexing of CRISPR is enabled by means of multi-target guide RNAs (mgRNAs), degenerate guide RNAs that direct Cas9 to a pre-determined number of well-mapped sites. mgRNAs uncovered generalizable insights into Cas9 binding and cleavage, revealing rapid post-cleavage Cas9 departure and repair factor loading at protospacer adjacent motif-proximal genomic DNA. Moreover, by bypassing confounding effects from guide RNA sequence, mgRNAs unveiled that Cas9 binding is enhanced at chromatin-accessible regions, and cleavage by bound Cas9 is more efficient near transcribed regions. Combined with light-mediated activation and deactivation of Cas9 activity, mgRNAs further enabled high-throughput study of the cellular response to double-strand breaks with high temporal resolution, revealing the presence, extent (under 2 kb) and kinetics (~1 h) of reversible DNA damage-induced chromatin decompaction. Altogether, this work establishes mgRNAs as a generalizable platform for multiplexing CRISPR and advances our understanding of intracellular Cas9 activity and the DNA damage response at endogenous loci.

Correlation between Frozen Section and Permanent Histopathologic Diagnoses in Adult Orbital Lesions.

Introduction: When indicated, intraoperative use of frozen sections may assist in determining the surgical course or appropriate processing of surgical specimens. Knowing the accuracy of a preliminary frozen section diagnosis is important. The purpose of this study is to determine the rate of correlation between frozen and permanent histopathologic diagnoses of adult orbital lesions, analyze characteristics of discordant cases, and examine the effects of discordance on surgical decision-making. Methods: A 15-year retrospective chart review was conducted at a tertiary care center of all adult patients with orbital lesions for which frozen section and corresponding permanent section tissue diagnoses were obtained. Results: Sixty-five orbital surgeries were performed with a total of 89 frozen sections sampled. In 63 surgeries (96.9%), at least 1 frozen section diagnosis matched the final permanent section diagnosis. Overall, frozen section diagnosis corresponded with permanent section diagnosis in 81 of 89 (91.0%) specimens. Of the 8 (9.0%) specimens from 5 unique patients that did not correlate, the final diagnoses on permanent sections were amyloidosis (5), margin-positive infiltrating breast carcinoma (2), and lymphoid hyperplasia (1). The discrepancy between frozen and permanent sections did not alter care in any patient. Conclusion: Frozen section diagnoses correlate with permanent histopathologic tissue diagnosis in adult orbital biopsies in greater than 90% of cases. Among non-correlated specimens, amyloidosis was the most common diagnosis. Although rare, orbital amyloid disorders may be considered in the differential diagnosis of cases of orbital biopsies with nonspecific findings on a frozen section.

Differences in treatment and survival in young and elderly patients with colorectal cancer.

INTRODUCTION: The incidence of colorectal cancer (CRC) in patients ≤ 40 years of age seems to follow an increasing trend worldwide. Previous studies have reported conflicting data on treatment intensity and survival in young patients with CRC. The aim of this study was to describe treatment and survival data in a national cohort of young Danish CRC patients in the 2001-2013 period and to compare these data with data on a national cohort of elderly patients with CRC. METHODS: In a retrospective study design, we analysed data on pre-operative management, treatment and overall survival in a national cohort of 484 young (18-40 years) and 14,647 elderly (66-75 years) CRC patients. Cox regression models were used to calculate adjusted hazard functions of overall survival. RESULTS: Surgical treatment did not differ markedly between age groups, but young patients received more oncological treatment and had a better stage-specific five-year overall survival than elderly patients. In an adjusted model, the hazard ratio for young patients with stage I-III disease was 0.67 (95% confidence interval (CI): 0.48-0.95) for colon cancer; 0.61 (95% CI: 0.37-0.99) for rectal cancer. CONCLUSION: Despite more advanced clinical stages of disease, young CRC patients had a better survival than elderly CRC patients in this national cohort. FUNDING: The study was funded by Krista og Viggo Petersens Fond; Civilingeniør Bengt Bøgh og Hustru Inge Bøghs Fond; and Arvekapitalen efter Ane Mette Nielsen til lægevidenskabelig forskning ved Vejle Sygehus. TRIAL REGISTRATION: The project was approved by DCCG (2013-03), the Danish Data Protection Agency (2008-58-0035) and the Regional Scientific Ethical Committee for Southern Denmark (S-20130079).

Young children with a minor traumatic head injury: clinical observation or CT scan?

Currently, in young children with minor traumatic head injuries (MTHI) classified as intermediate risk (IR), PECARN recommends clinical observation over computer tomography (CT) scan depending on provider comfort, although both options being possible. In this study, we describe clinicians' choice and which factors were associated with this decision. This was a planned sub-study of a prospective multicenter observational study that enrolled 1006 children younger than 18 years with MTHI who presented to six emergency departments in The Netherlands. Of those, 280 children classified as IR group fulfilling one or more minor criteria, leaving the clinician with the choice between clinical observation and a CT scan. In our cohort, 228/280 (81%) children were admitted for clinical observation, 15/280 (5.4%) received a CT scan, 6/280 (2.1%) received a CT scan and were admitted for observation, and 31/280 (11%) children were discharged from the emergency department without any intervention. Three objective factors were associated with a CT scan, namely age above 2 years, the presence of any loss of consciousness (LOC), and presentation on weekend days. CONCLUSION: In children with MTHI in an IR group, clinicians prefer clinical observation above performing a CT scan. Older age, day of presentation, and any loss of consciousness are factors associated with a CT scan. WHAT IS KNOWN: • Clinical decision rules have been developed in the management of children of different risk groups with minor traumatic head injury (MTHI). • According to the Dutch national, clinical decision rules in children under 6 years of age up to 50% of children classify as intermediate risk (IR) and clinicians may choose between clinical observation and computed tomography (CT). WHAT IS NEW: • In this IR group, clinical observation is chosen in 81% children with MTHI. • In the subgroup where clinicians performed a CT scan, children were older and presented more frequently on a weekend day, and more frequently consciousness was lost.