Efficient transmission of human prion diseases to a glycan-free prion protein-expressing host.

It is increasingly evident that the association of glycans with the prion protein (PrP), a major post-translational modification, significantly impacts the pathogenesis of prion diseases. A recent bioassay study has provided evidence that the presence of PrP glycans decreases spongiform degeneration and disease-related PrP (PrPD) deposition in a murine model. We challenged (PRNPN181Q/197Q) transgenic (Tg) mice expressing glycan-free human PrP (TgGlyc-), with isolates from sporadic Creutzfeldt-Jakob disease subtype MM2 (sCJDMM2), sporadic fatal insomnia and familial fatal insomnia, three human prion diseases that are distinct but share histotypic and PrPD features. TgGlyc- mice accurately replicated the basic histotypic features associated with the three diseases but the transmission was characterized by high attack rates, shortened incubation periods and a greatly increased severity of the histopathology, including the presence of up to 40 times higher quantities of PrPD that formed prominent deposits. Although the engineered protease-resistant PrPD shared at least some features of the secondary structure and the presence of the anchorless PrPD variant with the wild-type PrPD, it exhibited different density gradient profiles of the PrPD aggregates and a higher stability index. The severity of the histopathological features including PrP deposition appeared to be related to the incubation period duration. These findings are clearly consistent with the protective role of the PrP glycans but also emphasize the complexity of the conformational changes that impact PrPD following glycan knockout. Future studies will determine whether these features apply broadly to other human prion diseases or are PrPD-type dependent.

Laparoscopic Total Pancreatectomy After Laparoscopic Whipple.

BACKGROUND: The incidence of a second de novo pancreatic ductal adenocarcinoma (PDAC) among patients with prior cancer has been reported to be 6%.1,2 however, as survival increases through improvements in systemic therapy, this incidence of a de novo PDAC after prior PDAC may become more prevalent.3-8 In this context, a structured and stepwise approach to a total pancreatectomy for a second de novo PDAC after a prior PDAC treated with a pancreaticoduodenectomy is detailed. PATIENTS: We present two similar cases. The first patient was a 71-year-old female with de novo body PDAC, and the second was a 50-year-old female with de novo tail PDAC. To rule out recurrence, immunohistochemical staining as well as the review of biopsies by two experienced pathologists were employed. Both patients had undergone a laparoscopic pancreatoduodenectomy for PDAC 4 and 3 years prior. Each patient received four cycles of neoadjuvant chemotherapy and underwent a safe laparoscopic total pancreatectomy. TECHNIQUE: Prior to surgery, three-dimensional anatomic and port site modeling is performed to optimize the understanding of the spatial relationship between the tumor, blood vessels, and adjacent organs involved. The port site modeling (including pneumoperitoneum simulation) focuses on the optimal port set-up for dissecting the biliopancreatic limb off the portal vein. Following complete mobilization of the biliopancreatic limb, the biliopancreatic limb is staple-divided between the hepatico- and pancreaticojejunostomy. Great care must be taken to avoid accidental staple injury to the hepatic artery or celiac trunk. The remainder of the dissection is akin to a standard distal pancreaticosplenectomy. CONCLUSION: Virtual pancreatectomy modeling facilitates an optimal set-up for the critical step of this case, i.e. dissection of the pancreaticojejunostomy off the portal vein. Early division of the biliopancreatic limb between hepatico- and pancreatojejunostomy is crucial to facilitating the remainder of the dissection. Laparoscopic total pancreatectomy for a de novo PDAC after laparoscopic pancreaticoduodenectomy may become more common as survival of patients with prior PDAC improves over time.

Large-scale validation of skin prion seeding activity as a biomarker for diagnosis of prion diseases.

Definitive diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD) relies on the examination of brain tissues for the pathological prion protein (PrPSc). Our previous study revealed that PrPSc-seeding activity (PrPSc-SA) is detectable in skin of sCJD patients by an ultrasensitive PrPSc seed amplification assay (PrPSc-SAA) known as real-time quaking-induced conversion (RT-QuIC). A total of 875 skin samples were collected from 2 cohorts (1 and 2) at autopsy from 2-3 body areas of 339 cases with neuropathologically confirmed prion diseases and non-sCJD controls. The skin samples were analyzed for PrPSc-SA by RT-QuIC assay. The results were compared with demographic information, clinical manifestations, cerebrospinal fluid (CSF) PrPSc-SA, other laboratory tests, subtypes of prion diseases defined by the methionine (M) or valine (V) polymorphism at residue 129 of PrP, PrPSc types (#1 or #2), and gene mutations in deceased patients. RT-QuIC assays of the cohort #1 by two independent laboratories gave 87.3% or 91.3% sensitivity and 94.7% or 100% specificity, respectively. The cohort #2 showed sensitivity of 89.4% and specificity of 95.5%. RT-QuIC of CSF available from 212 cases gave 89.7% sensitivity and 94.1% specificity. The sensitivity of skin RT-QuIC was subtype dependent, being highest in sCJDVV1-2 subtype, followed by VV2, MV1-2, MV1, MV2, MM1, MM1-2, MM2, and VV1. The skin area next to the ear gave highest sensitivity, followed by lower back and apex of the head. Although no difference in brain PrPSc-SA was detected between the cases with false negative and true positive skin RT-QuIC results, the disease duration was significantly longer with the false negatives [12.0 ± 13.3 (months, SD) vs. 6.5 ± 6.4, p < 0.001]. Our study validates skin PrPSc-SA as a biomarker for the detection of prion diseases, which is influenced by the PrPSc types, PRNP 129 polymorphisms, dermatome sampled, and disease duration.

Genome-wide association studies identify novel loci in rapidly progressive Alzheimer's disease.

INTRODUCTION: Recent data suggest that distinct prion-like amyloid beta and tau strains are associated with rapidly progressive Alzheimer's disease (rpAD). The role of genetic factors in rpAD is largely unknown. METHODS: Previously known AD risk loci were examined in rpAD cases. Genome-wide association studies (GWAS) were performed to identify variants that influence rpAD. RESULTS: We identified 115 pathology-confirmed rpAD cases and 193 clinical rpAD cases, 80% and 69% were of non-Hispanic European ancestry. Compared to the clinical cohort, pathology-confirmed rpAD had higher frequencies of apolipoprotein E (APOE) ε4 and rare missense variants in AD risk genes. A novel genome-wide significant locus (P < 5×10-8 ) was observed for clinical rpAD on chromosome 21 (rs2832546); 102 loci showed suggestive associations with pathology-confirmed rpAD (P < 1×10-5 ). DISCUSSION rpAD constitutes an extreme subtype of AD with distinct features. GWAS found previously known and novel loci associated with rpAD. Highlights Rapidly progressive Alzheimer's disease (rpAD) was defined with different criteria. Whole genome sequencing identified rare missense variants in rpAD. Novel variants were identified for clinical rpAD on chromosome 21.

Incidence and Relative Burden of Surgical Site Infections in Children Undergoing Nonemergent Surgery: Implications for Performance Benchmarking and Prioritization of Prevention Efforts.

OBJECTIVE: To establish surgical site infection (SSI) performance benchmarks in pediatric surgery and to develop a prioritization framework for SSI prevention based on procedure-level SSI burden. BACKGROUND: Contemporary epidemiology of SSI rates and event burden in elective pediatric surgery remain poorly characterized. METHODS: Multicenter analysis using sampled SSI data from 90 hospitals participating in NSQIP-Pediatric and procedural volume data from the Pediatric Health Information System (PHIS) database. Procedure-level incisional and organ space SSI (OSI) rates for 17 elective procedure groups were calculated from NSQIP-Pediatric data and estimates of procedure-level SSI burden were extrapolated using procedural volume data. The relative contribution of each procedure to the cumulative sum of SSI events from all procedures was used as a prioritization framework. RESULTS: A total of 11,689 nonemergent procedures were included. The highest incisional SSI rates were associated with gastrostomy closure (4.1%), small bowel procedures (4.0%), and gastrostomy (3.7%), while the highest OSI rates were associated with esophageal atresia/tracheoesophageal fistula repair (8.1%), colorectal procedures (1.8%), and small bowel procedures (1.5%). 66.1% of the cumulative incisional SSI burden from all procedures were attributable to 3 procedure groups (gastrostomy: 27.5%, small bowel: 22.9%, colorectal: 15.7%), and 72.8% of all OSI events were similarly attributable to 3 procedure groups (small bowel: 28.5%, colorectal: 26.0%, esophageal atresia/tracheoesophageal fistula repair: 18.4%). CONCLUSIONS: A small number of procedures account for a disproportionate burden of SSIs in pediatric surgery. The results of this analysis can be used as a prioritization framework for refocusing SSI prevention efforts where they are needed most.

A novel subtype of sporadic Creutzfeldt-Jakob disease with PRNP codon 129MM genotype and PrP plaques.

The presence of amyloid kuru plaques is a pathological hallmark of sporadic Creutzfeldt-Jakob disease (sCJD) of the MV2K subtype. Recently, PrP plaques (p) have been described in the white matter of a small group of CJD (p-CJD) cases with the 129MM genotype and carrying resPrPD type 1 (T1). Despite the different histopathological phenotype, the gel mobility and molecular features of p-CJD resPrPD T1 mimic those of sCJDMM1, the most common human prion disease. Here, we describe the clinical features, histopathology, and molecular properties of two distinct PrP plaque phenotypes affecting the gray matter (pGM) or the white matter (pWM) of sCJD cases with the PrP 129MM genotype (sCJDMM). Prevalence of pGM- and pWM-CJD proved comparable and was estimated to be ~ 0.6% among sporadic prion diseases and ~ 1.1% among the sCJDMM group. Mean age at onset (61 and 68 years) and disease duration (~ 7 months) of pWM- and pGM-CJD did not differ significantly. PrP plaques were mostly confined to the cerebellar cortex in pGM-CJD, but were ubiquitous in pWM-CJD. Typing of resPrPD T1 showed an unglycosylated fragment of ~ 20 kDa (T120) in pGM-CJD and sCJDMM1 patients, while a doublet of ~ 21-20 kDa (T121-20) was a molecular signature of pWM-CJD in subcortical regions. In addition, conformational characteristics of pWM-CJD resPrPD T1 differed from those of pGM-CJD and sCJDMM1. Inoculation of pWM-CJD and sCJDMM1 brain extracts to transgenic mice expressing human PrP reproduced the histotype with PrP plaques only in mice challenged with pWM-CJD. Furthermore, T120 of pWM-CJD, but not T121, was propagated in mice. These data suggest that T121 and T120 of pWM-CJD, and T120 of sCJDMM1 are distinct prion strains. Further studies are required to shed light on the etiology of p-CJD cases, particularly those of T120 of the novel pGM-CJD subtype.

CryoEM Structure with ATP Synthase Enables Late-Stage Diversification of Cruentaren†A.

Cruentaren A is a natural product that exhibits potent antiproliferative activity against various cancer cell lines, yet its binding site within ATP synthase remained unknown, thus limiting the development of improved analogues as anticancer agents. Herein, we report the cryogenic electron microscopy (cryoEM) structure of cruentaren A bound to ATP synthase, which allowed the design of new inhibitors through semisynthetic modification. Examples of cruentaren A derivatives include a trans-alkene isomer, which was found to exhibit similar activity to cruentaren A against three cancer cell lines as well as several other analogues that retained potent inhibitory activity. Together, these studies provide a foundation for the generation of cruentaren A derivatives as potential therapeutics for the treatment of cancer.

Neurosurgical Implant Safety in 7 T MRI: A Scoping Review.

The use of 7 Tesla (T) magnetic resonance imaging (MRI) is expanding across neurosurgical and neurologic specialties. However, few neurosurgical-related implants have been tested for safety at 7 T, limiting its use in patients with cranial fixation, shunt placements, and other implants. Implant safety can be determined via the American Society for Testing Materials International (ASTM) guidelines. To assess the current state of neurosurgical implant safety at 7 T, a systematic search was performed using PubMed, MEDLINE, Web of Knowledge, and citation matching. Studies written in English that included at least one neurosurgical implant and at least one safety outcome were included. Data were extracted for implant studied, implant composition, deflection angle, torque, temperature change, and ASTM guidelines followed. PRISMA reporting guidelines for scoping reviews were followed. Overall, 18 studies consisting of 45 unique implants were included. Implants included cranial fixation devices, aneurysm clips, spinal rods, pedicle screws, ventriculoperitoneal (VP) shunts, deep brain stimulation devices, and electroencephalogram (EEG) caps and electrodes. Cranial fixation devices, deep brain stimulation devices, spinal rods, and pedicle screws are likely 7 T MRI compatible based on outcomes reported. Aneurysm clips and EEG devices had variable safety outcomes. The VP shunts studied lost functionality after 7 T MRI exposure. We identified several implants that are likely compatible with 7 T MRI. Given the growth in 7 T imaging and expansion of the technology, neurosurgical implants should be constructed with the aforementioned considerations. Caution must be taken with all implants, especially aneurysm clips, programmable VP shunts, and EEG recording devices. It is also noteworthy that several implant testing reports did not report following ASTM standards. This scoping review seeks to concisely summarize all neurosurgical-related implants that have been tested for safety in 7 T MRI. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 2.

The role of modeling studies in asthma management and clinical decision-making: a Delphi survey of physician knowledge and perceptions.

OBJECTIVE: To investigate the knowledge and perceptions of physicians on the role of modeling studies in asthma, using a modified Delphi procedure. METHODS: Group opinions among a panel of respiratory experts were obtained using two online questionnaires and a virtual scientific workshop. A consensus was pre-defined as agreement by >75% of participants. RESULTS: From 26 experts who agreed to participate, 22 completed both surveys. At the end of the process, the panel rated their own understanding of modeling as good (77%) but that among physicians in general as poor (77%). Participants agreed that data from modeling studies should be used, at least sometimes, to inform treatment guidelines (91%) and could be useful for guiding clinical decisions (100%). Perceived barriers to using modeling studies were 'A lack of understanding' (81%) and 'A lack of standardized methodology' (82%). Based on data from two modeling studies, no consensus was reached on physicians recommending regular inhaled corticosteroids (ICS) versus as-needed therapy for patients with mild asthma, whereas 77% agreed that they would recommend regular ICS over maintenance and reliever therapy for ≥80% of their patients with moderate asthma. No consensus was reached on the value of modeling data in relation to empirical data. CONCLUSION: There is overall support among respiratory experts for the usefulness of modeling data to guide asthma treatment guidelines and clinical decision making. More publications on modeling data using robust models and accessible terminology will aid the understanding of physicians in general and help clarify the evidence-based value of modeling studies.

Severe Obesity Associated With Pituitary Corticotroph Hyperplasia and Neoplasia.

OBJECTIVE: To investigate the incidence of corticotroph hyperplasia (CH) or lymphocyte infiltration in the pituitary of patients with obesity. METHODS: The pituitary and adrenal glands from 161 adult autopsies performed between 2010 and 2019 at our institution were reviewed. The clinical history, body mass index (BMI), and cause of death were recorded. Routine hematoxylin and eosin staining, reticulin staining, and immunohistochemical staining for adrenocorticotropic hormone, CD3, and CD20 were performed. The results were analyzed using the Fisher and chi-square statistics. Decedents were separated into 4 groups based on BMI (kg/m2): (1) lean (BMI, <25.0), (2) overweight (BMI, 25.0-29.9), (3) obesity class I (BMI, 30.0-34.9), and (4) obesity classes II to III (BMI, >34.9). RESULTS: CH/neoplasia was identified in 44 of 161 pituitary glands. Four (9.1%) of 53 lean patients had pituitary lesions, whereas 27.3% (12) of overweight, 22.7% (10) of obesity class I, and 40.9% (18) of obesity class II patients had hyperplasia (P < .0001). Small corticotroph tumors were identified in 15 patients; only 1 was a lean patient, and the tumor was associated with the Crooke hyaline change of nontumorous corticotrophs. The presence of CH and neoplasia was associated with adrenal cortical hyperplasia and lipid depletion. Microscopic foci of T and B lymphocytes were identified in the pituitaries of patients in each weight category; no independent association between BMI and lymphocyte inflammation was found. CONCLUSION: Our data indicate an association between CH/neoplasia and obesity. It remains unclear whether obesity is the cause or effect of adrenocorticotropic hormone and cortisol excess.

Characterization of postoperative LASIK ectasia features on higher-order aberration excimer ablation maps.

BACKGROUND: To characterize anterior corneal higher-order aberration (HOA) excimer ablation map patterns in postoperative LASIK ectasia (POE) and to examine correlations between newly identified corneal HOA ablation map features of POE and known topographic indices. METHODS: Prospective multicenter non-interventional descriptive study. A total of 28 eyes from 22 POE patients were enrolled. The postoperative HOA ablation map was derived from Topolyzer Vario corneal imaging at the time of POE diagnosis. Features that recurred were identified and then analyzed. Correlations to Orbscan indices were studied. RESULTS: An arrangement of two elliptical paracentral ablation islands, deep inferior and shallow superior, in direct mirror-like opposition to each other, were identified on all HOA maps. The paracentral islands were accompanied by peripheral ablation crescents. The deep paracentral inferior island 'hot spot' coincided with the topographical apical POE cone and was highly reproducible in angular position (249.3 ± 17.3°). There was significant variation in ablation depth (shallow superior island: 11.5 ± 6.9 µm and deep inferior island: 32.5 ± 18.8 µm). The superior crescents had high variability in depth (34.8 ± 18.9 µm). Strong correlations were found between the corneal irregularity index and the ablation depth difference between the deep and shallow paracentral islands (R = 0.96; P < 0.0001). CONCLUSION: The corneal HOA excimer ablation map revealed a recurring, distinct, easily recognizable pattern in POE eyes. Validated Orbscan POE indices and HOA ablation map islands showed a strong correlation. It is possible to extract useful information from the corneal HOA ablation map, potentially making it suitable for diagnosing and monitoring POE although more studies are needed.

Return to Sport Following Distal Triceps Repair.

PURPOSE: The purpose of this investigation was to examine the timeline of return-to-sport following distal triceps repair; evaluate the degree of participation and function upon returning to sport; and identify risk factors for failure to return to sport. METHODS: Patients who underwent distal triceps repair with a minimum of 1 year of follow-up were retrospectively reviewed. Patients completed a subjective sports questionnaire and were scored on a visual analog scale for pain; the Mayo Elbow Performance Index; the Quick Disabilities of the Arm, Shoulder, and Hand; and the Single Assessment Numerical Evaluation. RESULTS: Out of 113 eligible patients who had a distal triceps repair, 81 patients (71.7%) were contacted. Sixty-eight patients (84.0%) who participated in sports prior to surgery were included at 6.0 ± 4.0 years after surgery, and the average age was 46.6 ± 11.5 years. Sixty-one patients (89.7%) resumed playing at least 1 sport by 5.9 ± 4.4 months following distal triceps repair. However, 18 patients (29.5%) returned to a lower level of activity intensity. The average postoperative Quick Disabilities of the Arm, Shoulder, and Hand; Mayo Elbow Performance; visual analog scale for pain; and Single Assessment Numerical Evaluation scores were 8.2 ± 14.0, 89.5 ± 13.4, 2.0 ± 1.7, and 82.2 ± 24.3, respectively. No patients underwent revision surgery at the time of final follow-up. CONCLUSIONS: Distal triceps repair enables 89.7% of patients to return to sport by 5.9 ± 4.4 months following surgery. However, 29.5% of patients were unable to return to their preinjury level of activity. It is imperative that patients are appropriately educated to manage postoperative expectations regarding sport participation following distal triceps repair. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Piperacillin-Tazobactam Compared With Cefoxitin as Antimicrobial Prophylaxis for Pancreatoduodenectomy: A Randomized Clinical Trial.

Importance: Despite improvements in perioperative mortality, the incidence of postoperative surgical site infection (SSI) remains high after pancreatoduodenectomy. The effect of broad-spectrum antimicrobial surgical prophylaxis in reducing SSI is poorly understood. Objective: To define the effect of broad-spectrum perioperative antimicrobial prophylaxis on postoperative SSI incidence compared with standard care antibiotics. Design, Setting, and Participants: Pragmatic, open-label, multicenter, randomized phase 3 clinical trial at 26 hospitals across the US and Canada. Participants were enrolled between November 2017 and August 2021, with follow-up through December 2021. Adults undergoing open pancreatoduodenectomy for any indication were eligible. Individuals were excluded if they had allergies to study medications, active infections, chronic steroid use, significant kidney dysfunction, or were pregnant or breastfeeding. Participants were block randomized in a 1:1 ratio and stratified by the presence of a preoperative biliary stent. Participants, investigators, and statisticians analyzing trial data were unblinded to treatment assignment. Intervention: The intervention group received piperacillin-tazobactam (3.375 or 4 g intravenously) as perioperative antimicrobial prophylaxis, while the control group received cefoxitin (2 g intravenously; standard care). Main Outcomes and Measures: The primary outcome was development of postoperative SSI within 30 days. Secondary end points included 30-day mortality, development of clinically relevant postoperative pancreatic fistula, and sepsis. All data were collected as part of the American College of Surgeons National Surgical Quality Improvement Program. Results: The trial was terminated at an interim analysis on the basis of a predefined stopping rule. Of 778 participants (378 in the piperacillin-tazobactam group [median age, 66.8 y; 233 {61.6%} men] and 400 in the cefoxitin group [median age, 68.0 y; 223 {55.8%} men]), the percentage with SSI at 30 days was lower in the perioperative piperacillin-tazobactam vs cefoxitin group (19.8% vs 32.8%; absolute difference, -13.0% [95% CI, -19.1% to -6.9%]; P < .001). Participants treated with piperacillin-tazobactam, vs cefoxitin, had lower rates of postoperative sepsis (4.2% vs 7.5%; difference, -3.3% [95% CI, -6.6% to 0.0%]; P = .02) and clinically relevant postoperative pancreatic fistula (12.7% vs 19.0%; difference, -6.3% [95% CI, -11.4% to -1.2%]; P = .03). Mortality rates at 30 days were 1.3% (5/378) among participants treated with piperacillin-tazobactam and 2.5% (10/400) among those receiving cefoxitin (difference, -1.2% [95% CI, -3.1% to 0.7%]; P = .32). Conclusions and Relevance: In participants undergoing open pancreatoduodenectomy, use of piperacillin-tazobactam as perioperative prophylaxis reduced postoperative SSI, pancreatic fistula, and multiple downstream sequelae of SSI. The findings support the use of piperacillin-tazobactam as standard care for open pancreatoduodenectomy. Trial Registration: ClinicalTrials.gov Identifier: NCT03269994.

A discriminative event-based model for subtype diagnosis of sporadic Creutzfeldt-Jakob disease using brain MRI.

INTRODUCTION: Sporadic Creutzfeldt-Jakob disease (sCJD) comprises multiple subtypes (MM1, MM2, MV1, MV2C, MV2K, VV1, and VV2) with distinct disease durations and spatiotemporal cascades of brain lesions. Our goal was to establish the ante mortem diagnosis of sCJD subtype, based on patient-specific estimates of the spatiotemporal cascade of lesions detected by diffusion-weighted magnetic resonance imaging (DWI). METHODS: We included 488 patients with autopsy-confirmed diagnosis of sCJD subtype and 50 patients with exclusion of prion disease. We applied a discriminative event-based model (DEBM) to infer the spatiotemporal cascades of lesions, derived from the DWI scores of 12 brain regions assigned by three neuroradiologists. Based on the DEBM cascades and the prion protein genotype at codon 129, we developed and validated a novel algorithm for the diagnosis of the sCJD subtype. RESULTS: Cascades of MM1, MM2, MV1, MV2C, and VV1 originated in the parietal cortex and, following subtype-specific orderings of propagation, went toward the striatum, thalamus, and cerebellum; conversely, VV2 and MV2K cascades showed a striatum-to-cortex propagation. The proposed algorithm achieved 76.5% balanced accuracy for the sCJD subtype diagnosis, with low rater dependency (differences in accuracy of ± 1% among neuroradiologists). DISCUSSION: Ante mortem diagnosis of sCJD subtype is feasible with this novel data-driven approach, and it may be valuable for patient prognostication, stratification in targeted clinical trials, and future therapeutics. HIGHLIGHTS: Subtype diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD) is achievable with diffusion MRI. Cascades of diffusion MRI abnormalities in the brain are subtype-specific in sCJD. We proposed a diagnostic algorithm based on cascades of diffusion MRI abnormalities and demonstrated that it is accurate. Our method may aid early diagnosis, prognosis, stratification in clinical trials, and future therapeutics. The present approach is applicable to other neurodegenerative diseases, enhancing the differential diagnoses.

Distinct conformers of amyloid beta accumulate in the neocortex of patients with rapidly progressive Alzheimer's disease.

Amyloid beta (Aß) deposition in the neocortex is a major hallmark of Alzheimer's disease (AD), but the extent of deposition does not readily explain phenotypic diversity and rate of disease progression. The prion strain-like model of disease heterogeneity suggests the existence of different conformers of Aß. We explored this paradigm using conformation-dependent immunoassay (CDI) for Aß and conformation-sensitive luminescent conjugated oligothiophenes (LCOs) in AD cases with variable progression rates. Mapping the Aß conformations in the frontal, occipital, and temporal regions in 20 AD patients with CDI revealed extensive interindividual and anatomical diversity in the structural organization of Aß with the most significant differences in the temporal cortex of rapidly progressive AD. The fluorescence emission spectra collected in situ from Aß plaques in the same regions demonstrated considerable diversity of spectral characteristics of two LCOs-quatroformylthiophene acetic acid and heptaformylthiophene acetic acid. Heptaformylthiophene acetic acid detected a wider range of Aß deposits, and both LCOs revealed distinct spectral attributes of diffuse and cored plaques in the temporal cortex of rapidly and slowly progressive AD and less frequent and discernible differences in the frontal and occipital cortex. These and CDI findings indicate a major conformational diversity of Aß accumulating in the neocortex, with the most notable differences in temporal cortex of cases with shorter disease duration, and implicate distinct Aß conformers (strains) in the rapid progression of AD.

Subtype Diagnosis of Sporadic Creutzfeldt-Jakob Disease with Diffusion Magnetic Resonance Imaging.

OBJECTIVE: Sporadic Creutzfeldt-Jakob disease (sCJD) comprises several subtypes as defined by genetic and prion protein characteristics, which are associated with distinct clinical and pathological phenotypes. To date, no clinical test can reliably diagnose the subtype. We established two procedures for the antemortem diagnosis of sCJD subtype using diffusion magnetic resonance imaging (MRI). METHODS: MRI of 1,458 patients referred to the National Prion Disease Pathology Surveillance Center were collected through its consultation service. One neuroradiologist blind to the diagnosis scored 12 brain regions and generated a lesion profile for each MRI scan. We selected 487 patients with autopsy-confirmed diagnosis of "pure" sCJD subtype and at least one positive diffusion MRI examination. We designed and tested two data-driven procedures for subtype diagnosis: the first procedure-prion subtype classification algorithm with MRI (PriSCA_MRI)-uses only MRI examinations; the second-PriSCA_MRI + Gen-includes knowledge of the prion protein codon 129 genotype, a major determinant of sCJD subtypes. Both procedures were tested on the first MRI and the last MRI follow-up. RESULTS: PriSCA_MRI classified the 3 most prevalent subtypes with 82% accuracy. PriSCA_MRI + Gen raised the accuracy to 89% and identified all subtypes. Individually, the 2 most prevalent sCJD subtypes, MM1 and VV2, were diagnosed with sensitivities up to 95 and 97%, respectively. The performances of both procedures did not change in 168 patients with longitudinal MRI studies when the last examination was used. INTERPRETATION: This study provides the first practical algorithms for antemortem diagnosis of sCJD subtypes. MRI diagnosis of subtype is likely to be attainable at early disease stages to prognosticate clinical course and design future therapeutic trials. ANN NEUROL 2021;89:560-572.

Synthesis and Evaluation of Simplified Cruentaren A Analogues.

The 90 kDa heat shock protein (Hsp90) belongs to a group of molecular chaperones that regulate homeostasis via the folding of nascent polypeptides into their biologically active proteins, many of which are involved in cancer development and progression. As a result, inhibition of Hsp90 is an exciting area of research for the treatment of cancer. However, most of the 18 Hsp90 N-terminal inhibitors evaluated in clinical trials exhibited deleterious side effects and toxicities. Cruentaren A is a natural product that manifests potent anticancer activity against various human cancer cell lines via disruption of interactions between Hsp90α and F1FO ATP synthase, which does not induce the pro-survival, heat shock response, a major limitation associated with current Hsp90 inhibitors. However, the development of cruentaren A as a new anticancer agent has been hindered by its complex structure. Herein, we systematically removed the functionalities present in fragment 2 of cruentaren A and incorporated some key structural modifications from previous work, which produced 12 simplified analogues. Our studies determined that all functional groups present in fragment 2 are essential for cruentaren A's anticancer activity.

Surgical Outcomes in Canada and the United States: An Analysis of the ACS-NSQIP Clinical Registry.

BACKGROUND: There has been longstanding uncertainty over whether lower healthcare spending in Canada might be associated with inferior outcomes for hospital-based care. We hypothesized that mortality and surgical complication rates would be higher for patients who underwent four common surgical procedures in Canada as compared to the US. DESIGN, SETTING, AND PARTICIPANTS: We conducted a retrospective cohort study of all adults who underwent hip fracture repair, colectomy, pancreatectomy, or spine surgery in 96 Canadian and 585 US hospitals participating in the American College of Surgeons National Surgical Quality Improvement Project (ACS-NSQIP) between January 1, 2015 and December 31, 2019. We compared patients with respect to demographic characteristics and comorbidity. We then compared unadjusted and adjusted outcomes within 30-days of surgery for patients in Canada and the US including: (1) Mortality; (2) A composite constituting 1-or-more of the following complications (cardiac arrest; myocardial infarction; pneumonia; renal failure/; return to operating room; surgical site infection; sepsis; unplanned intubation). RESULTS: Our hip fracture cohort consisted of 21,166 patients in Canada (22.3%) and 73,817 in the US (77.7%), for colectomy 21,279 patients in Canada (8.9%) and 218,307 (91.1%), for pancreatectomy 873 (7.8%) in Canada and 12,078 (92.2%) in the US, and for spine surgery 14,088 (5.3%) and 252,029 (94.7%). Patient sociodemographics and comorbidity were clinically similar between jurisdictions. In adjusted analyses odds of death was significantly higher in Canada for two procedures (colectomy (OR 1.22; 95% CI 1.044-1.424; P = .012) and pancreatectomy (OR 2.11; 95% CI 1.26-3.56; P = .005)) and similar for hip fracture and spine surgery. Odds of the composite outcome were significantly higher in Canada for all 4 procedures, largely driven by higher risk of cardiac events and post-operative infections. CONCLUSIONS: We found evidence of higher rates of mortality and surgical complications within 30-days of surgery for patients in Canada as compared to the US.

Traction Tenolysis for Flexor Tendon Adhesions: Outcomes in 97 Patients.

PURPOSE: Traction tenolysis is an alternative, less invasive way of performing flexor tendon tenolysis by winding affected tendons around a surgical instrument. This study assessed outcomes and complications in a cohort of patients who underwent traction tenolysis to determine its effectiveness. METHODS: We retrospectively reviewed 97 patients who underwent traction tenolysis performed by 4 fellowship-trained hand surgeons from 2010 to 2019. We collected data on preoperative and postoperative ranges of motion, the number and type of prior ipsilateral hand surgeries, and the duration of therapy and follow-up. Cases of traditional open tenosynovectomy tenolysis were excluded. RESULTS: Approximately two-thirds of the patients achieved more than 75% of the normal total active motion, and 80% achieved at least 50% of the normal total active motion. The mean total active flexion increased significantly by 42° and passive flexion by 25°. The differences in active and passive flexion significantly decreased from 28° before the surgery to 9° after the surgery. The active and passive flexion of the distal interphalangeal and proximal interphalangeal joints improved similarly, at approximately 20° and 10°, respectively. The average duration of follow-up was 11 ± 8 weeks. The complication rate was 5%: 1 case of intraoperative flexor digitorum superficialis tendon rupture, 1 case of postoperative infection, and 3 reoperations because of failure to progress. CONCLUSIONS: Traction tenolysis is an alternative to traditional open tenolysis surgery in selected patients. LEVEL OF EVIDENCE: Therapeutic IV.

Relationship Between Preoperative and Postoperative Motion After Four-Corner Wrist Fusion for Osteoarthritis: Clustering and Regression Analyses.

PURPOSE: Four-corner fusion (4CF) is a surgical option for refractory scapholunate advanced collapse and scaphoid nonunion advanced collapse wrist arthritis. Preoperative range of motion (ROM) predicts outcomes in many orthopedic procedures. This study investigates ROM in a cohort of 4CF patients to examine the relationship between preoperative and postoperative motion and identifies different clinical patterns. METHODS: We performed a retrospective review of 4CF patients. Patients with a history of inflammatory arthritis and radiographic characteristics of inflammation were excluded. Demographics, prior wrist surgery history, and ROM data were collected at preoperative and postoperative intervals after cast removal at 8 weeks, 3 months, and 8 months. Regression analysis compared the motion before and after 4CF. Subsequent cluster analysis to reduce confounding compared postoperative motion differences in the top 20% to the bottom 20% of patients by preoperative motion. RESULTS: We included 148 patients; 27 had prior surgery on the ipsilateral wrist. Preoperative arc averaged 86° ± 28° (flexion 46° ± 17°, extension 40° ± 15°); 8-week arc 43° ± 19° (flexion 19° ± 12°, extension 24° ± 12°); 3-month arc 62° ± 17° (flexion 30° ± 12°, extension 32° ± 11°); and 8-month arc 74° ± 17° (flexion 36° ± 11°, extension 37° ± 12°). Preoperative and final arcs were (r = 0.39). Clustering by the preoperative arc, the top 20% (mean 124° ± 15°) achieved a mean final arc of 81° ± 16°, while the bottom 20% (mean 47° ± 16°) achieved a mean final arc of 65° ± 19°. Intercluster differences were statistically significant. The bottom 20% gained motion postoperatively. Most patients in the middle 60% did not differ significantly in postoperative motion. CONCLUSIONS: Although wrist motion following 4CF correlates positively with preoperative motion, most patients do not differ significantly in postoperative motion. Patients with substantial preoperative motion deficits gain motion after 4CF. This information is important when counseling patients, determining the timing of surgical intervention, and managing expectations related to motion outcomes. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic II.