In vivo efficacy of WCK 6777 (ertapenem/zidebactam) against carbapenemase-producing Klebsiella pneumoniae in the neutropenic murine pneumonia model.

OBJECTIVES: Ertapenem has proven to be an effective antimicrobial; however, increasing enzyme-mediated resistance has been noted. Combination with zidebactam, a ß-lactam enhancer, is restorative. Human-simulated regimens (HSRs) of ertapenem and zidebactam alone and in combination (WCK 6777; 2 g/2 g q24h) were assessed for efficacy against carbapenemase-producing Klebsiella pneumoniae (CP-KP) in the pneumonia model. METHODS: Infected ICR mice were rendered neutropenic and exposed to various doses of ertapenem and zidebactam alone and in combination to develop the HSRs that were subsequently confirmed in additional pharmacokinetic studies. Twenty-one CP-KP (KPC or OXA-48-like producers) with WCK 6777 MICs of 1-8 mg/L were utilized. Mice were treated for 24 h with saline or HSRs of ertapenem, zidebactam and WCK 6777. Efficacy was defined as change in mean lung bacterial density relative to 0 h. RESULTS: Confirmatory pharmacokinetic analysis showed agreement between predicted human exposures (%fT>MIC) and those achieved in vivo for all three HSRs. The 0 h bacterial density across all isolates was 6.69 ±â€Š0.31 log10 cfu/lungs. At 24 h, densities increased by 2.57 ±â€Š0.50, 2.2 ±â€Š0.60 and 2.05 ±â€Š0.71 log10 cfu/lungs in the 24 h control, ertapenem HSR and zidebactam HSR groups, respectively. Overall, 18/21 of the isolates exposed to the WCK 6777 HSR displayed a killing profile that exceeded the translational benchmark for efficacy of a 1 log10 cfu reduction. Among the remaining three isolates, two displayed ∼0.5 log10 kill and stasis was observed in the third. CONCLUSIONS: Human-simulated exposures of WCK 6777 demonstrated potent in vivo activity against CP-KP, including those with WCK 6777 MICs up to 8 mg/L.

Utilization and evolving prescribing practice of opioid and non-opioid analgesics in patients undergoing lymphadenectomy for cutaneous malignancy.

BACKGROUND AND OBJECTIVES: Opioids are commonly prescribed following surgery and can lead to persistent opioid use. We assessed changes in prescribing practices following an opioid education initiative for patients undergoing lymphadenectomy for cutaneous malignancy. METHODS: A single-institution retrospective study of all eligible patients (3/2016-3/2020) was performed. RESULTS: Indications for lymphadenectomy in 328 patients were metastatic melanoma (84%), squamous cell carcinoma (10%), and Merkel cell carcinoma (5%). At discharge, non-opioid analgesics were increasingly utilized over the 4-year study period, with dramatic increases after education initiatives (32%, 42%, 59%, and 79% of pts, respectively each year; p < 0.001). Median oral morphine equivalents (OMEs) prescribed also decreased dramatically starting in year 3 (250, 238, 150, and 100 mg, respectively; p < 0.001). Patients discharged with 200 mg OMEs were less likely to also be discharged with non-opioid analgesics (40% vs. 64%. respectively, p < 0.001). CONCLUSIONS: Analgesic prescribing practices following lymphadenectomy for cutaneous malignancy improved significantly over a 4-year period, with use of non-opioids more than doubling and a 60% reduction in median OME. Opportunities exist to further increase non-opioid use and decrease opioid dissemination after lymphadenectomy for cutaneous malignancy.

Machine-driven parameter screen of biochemical reactions.

The development of complex methods in molecular biology is a laborious, costly, iterative and often intuition-bound process where optima are sought in a multidimensional parameter space through step-by-step optimizations. The difficulty of miniaturizing reactions under the microliter volumes usually handled in multiwell plates by robots, plus the cost of the experiments, limit the number of parameters and the dynamic ranges that can be explored. Nevertheless, because of non-linearities of the response of biochemical systems to their reagent concentrations, broad dynamic ranges are necessary. Here we use a high-performance nanoliter handling platform and computer generation of liquid transfer programs to explore in quadruplicates 648 combinations of 4 parameters of a biochemical reaction, the reverse-transcription, which lead us to uncover non-linear responses, parameter interactions and novel mechanistic insights. With the increased availability of computer-driven laboratory platforms for biotechnology, our results demonstrate the feasibility and advantage of methods development based on reproducible, computer-aided exhaustive characterization of biochemical systems.

Guided tour of hidden tracts in the pelvis: exploring pelvic fistulas.

BACKGROUND: Fistulas are an abnormal connection between two or more epithelial surfaces. When fistulization between adjacent structures occurs in the pelvis, there is almost invariably significant associated morbidity and impact on a patient's quality of life. Imaging may aid in the diagnosis of pelvic fistulas and is essential to identify any associated pathology, define the course of the fistula, and aid in pre-surgical planning. PURPOSE: This article aims to review the wide array of clinical and imaging presentations of fistulas in the pelvis, with a focus on the radiologists' role in managing this challenging entity. METHODS: This article will review each classification type of fistula. RESULTS: Pelvic fistula is a devastating condition that causes significant morbidity and evaluation can be challenging. CONCLUSIONS: Imaging, and particularly MRI, plays a vital role in the diagnosis, characterizing the course of a fistula and demonstrating associated complications, which are essential to guide treatment decisions.

Imipenem/Cilastatin/Relebactam Alone and in Combination against Pseudomonas aeruginosa in the In Vitro Pharmacodynamic Model.

Combination therapy may enhance imipenem/cilastatin/relebactam's (I/R) activity against Pseudomonas aeruginosa and suppress resistance development. Human-simulated unbound plasma concentrations of I/R at 1.25 g every 6 h (h), colistin at 360 mg daily, and amikacin at 25 mg/kg daily were reproduced alone and in combination against six imipenem-nonsusceptible P. aeruginosa isolates in an in vitro pharmacodynamic model over 24 h. For I/R alone, the mean reductions in CFU ± the standard errors by 24 h were -2.52 ± 0.49, -1.49 ± 0.49, -1.15 ± 0.67, and -0.61 ± 0.10 log10 CFU/ml against isolates with MICs of 1/4, 2/4, 4/4, and 8/4 µg/ml, respectively. Amikacin alone also resulted in 24 h CFU reductions consistent with its MIC, while colistin CFU reductions did not differ. Resistant subpopulations were observed after 24 h in 1, 4, and 3 I/R-, colistin-, and amikacin-exposed isolates, respectively. The combination of I/R and colistin resulted in synergistic (n = 1) or additive (n = 2) interactions against three isolates with 24-h CFU reductions ranging from -2.62 to -4.67 log10 CFU/ml. The combination of I/R and amikacin exhibited indifferent interactions against all isolates, with combined drugs achieving -0.51- to -3.33-log10 CFU/ml reductions. No resistant subpopulations were observed during I/R and colistin combination studies, and when added to amikacin, I/R prevented the emergence of amikacin resistance. Against these six multidrug-resistant P. aeruginosa, I/R alone achieved significant CFU reductions against I/R-susceptible isolates. Combinations of I/R plus colistin resulted in additivity or synergy against some P. aeruginosa, whereas the addition of amikacin did not provide further antibacterial efficacy against these isolates.

Comparative In Vivo Antibacterial Activity of Human-Simulated Exposures of Cefiderocol and Ceftazidime against Stenotrophomonas maltophilia in the Murine Thigh Model.

Cefiderocol is a novel siderophore cephalosporin that utilizes bacterial ferric iron transports to cross the outer membrane. Cefiderocol shows high stability against all classes of ß-lactamases, rendering it extremely potent against carbapenem- and multidrug-resistant Gram-negative organisms. Using a neutropenic murine thigh model, we compared the efficacies of human-simulated exposures of cefiderocol (2 g Q8H 3 h infusion) and ceftazidime (2 g Q8H 2 h infusion) against Stenotrophomonas maltophilia, an emerging opportunistic Gram-negative organism associated with serious and often fatal nosocomial infections. Twenty-four S. maltophilia isolates were studied, including isolates resistant to ceftazidime, trimethoprim-sulfate, and/or levofloxacin. The thighs were inoculated with bacterial suspensions of 108 CFU/mL and the human-simulated regimens were administered over 24 h. Efficacy was measured as the change in log10CFU/thigh at 24 h compared with 0 h controls. Cefiderocol human-simulated exposure demonstrated potent bacterial killing; mean bacterial reduction at 24 h was -2.67 ± 0.68 log10CFU/thigh with ≥ 2 log-reduction achieved in 21 isolates (87.5%) and ≥ 1 log-reduction achieved in the remaining three isolates (12.5%). In comparison, ceftazidime human-simulated exposure produced mean bacterial reduction of -1.38 ± 1.49 log10CFU/thigh among 10 ceftazidime-susceptible isolates and mean bacterial growth of 0.64 ± 0.79 log10CFU/thigh among 14 ceftazidime-non-susceptible isolates. While ceftazidime showed modest efficacy against most susceptible isolates, humanized cefiderocol exposures resulted in remarkable in vivo activity against all S. maltophilia isolates examined, inclusive of ceftazidime-non-susceptible isolates. The potent in vitro and in vivo activity of cefiderocol supports the development of this novel compound for managing S. maltophilia infections.

Effect of Clinically Meaningful Antibiotic Concentrations on Recovery of Escherichia coli and Klebsiella pneumoniae Isolates from Anaerobic Blood Culture Bottles with and without Antibiotic Binding Resins.

Blood cultures are routinely collected in pairs of aerobic and anaerobic bottles. Artificial sterilization of Gram-negative bacteria in aerobic bottles containing clinically meaningful antibiotic concentrations has previously been observed. This study assessed recovery from anaerobic bottles with and without antibiotic binding resins. We studied the recovery of Escherichia coli and Klebsiella pneumoniae when exposed to meropenem, imipenem, cefepime, cefazolin, levofloxacin, and piperacillin-tazobactam in resin-containing BacT/Alert FN Plus and BD Bactec Plus anaerobic/F bottles as well as resin-free BacT/Alert SN and BD Bactec standard anaerobic bottles. Bottles were inoculated with bacteria and whole blood containing peak, midpoint, or trough concentrations and incubated for up to 120 hours in their respective detection systems. In E. coli resin-containing bottles, recovery was observed in 10/24 (42%), 17/24 (71%), and 18/24 (75%) (P = 0.034) of those exposed to peak, midpoint, and trough concentrations, respectively. In K. pneumoniae resin-containing bottles, recovery was observed in 8/16 (50%), 10/16 (63%), and 10/16 (63%) (P = 0.710), respectively. No growth was detected in bottles containing cefepime regardless of concentration, while recovery was observed in the presence of all concentrations of cefazolin and piperacillin-tazobactam. Recovery in bottles with meropenem and imipenem was more frequently observed in BacT/Alert FN Plus bottles compared with Bactec Plus bottles. Resin-free bottles demonstrated significantly lower recovery than bottles containing binding resin. Clinical concentrations of certain antibiotics can adversely affect detection of E. coli and K. pneumoniae in anaerobic blood culture bottles. Obtaining blood cultures immediately before a dose and utilizing resin-containing anaerobic bottles will maximize the likelihood of recovery.

Recovery of Gram-Negative Bacteria from Aerobic Blood Culture Bottles Containing Antibiotic Binding Resins after Exposure to ß-Lactam and Fluoroquinolone Concentrations.

Blood culture bottles containing antibiotic binding resins are routinely used to minimize artificial sterilization in the presence of antibiotics. However, the resin binding kinetics can differ between antibiotics and concentrations. This study assessed the impact of clinically meaningful peak, midpoint, and trough concentrations of meropenem, imipenem, cefepime, cefazolin, levofloxacin, and piperacillin-tazobactam on the recovery of Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae from resin-containing BacT/Alert FA Plus and Bactec Aerobic/F blood culture bottles. P. aeruginosa-inoculated bottles alarmed positive in 4/20 (20%), 16/20 (80%), and 20/20 (100%) of those with peak, midpoint, and trough concentrations of antipseudomonal agents, respectively (P ≤ 0.001). E. coli was recovered from 8/24 (33%), 11/24 (46%), and 14/24 (58%) of bottles with peak, midpoint, and trough concentrations, respectively (P = 0.221). K. pneumoniae was recovered from 8/16 (50%) at all concentrations of the studied antibiotics (P = 1.0). BacT/Alert and Bactec bottles inoculated with antibiotics and P. aeruginosa had similar times to detection (TTD) (P = 0.352); however, antibiotic-containing BacT/Alert bottles had a shorter TTD compared with antibiotic-containing Bactec bottles for E. coli (P = 0.026) and K. pneumoniae (P ≤ 0.001). Pathogen recovery in BacT/Alert FA Plus and Bactec Aerobic/F blood culture bottles containing antibiotic binding resins was greatly reduced in the presence of antibiotics, especially at higher concentrations. These data support the practice of drawing blood cultures immediately before an antibiotic dose to maximize the chances of pathogen recovery.

Social Network Factors as Correlates and Predictors of High Depressive Symptoms Among Black Men Who Have Sex with Men in HPTN 061.

Depression is linked to a range of poor HIV-related health outcomes. Minorities and men who have sex with men (MSM), suffer from high rates of depression. The current study examined the relationship between depressive symptoms and social network characteristics among community-recruited Black MSM in HPTN 061 from 6 US cities. A social network inventory was administer at baseline and depression was assessed with the CES-D at baseline, 6, and 12-months. At baseline, which included 1167 HIV negative and 348 HIV positive participants, size of emotional, financial, and medical support networks were significantly associated with fewer depressive symptoms. In longitudinal mixed models, size of emotional, financial, and medical support networks were significantly associated with fewer depressive symptoms as was the number of network members seen weekly. In the multivariate analyses, size of medical appointment network remained statistically significant (aOR 0.89, CI 0.81-0.98). These findings highlight the importance of network support of medical care on depression and suggest the value of support mobilization.

A Longitudinal Analysis of Treatment Optimism and HIV Acquisition and Transmission Risk Behaviors Among Black Men Who Have Sex with Men in HPTN 061.

Little is known about HIV treatment optimism and risk behaviors among Black men who have sex with men (BMSM). Using longitudinal data from BMSM in the HPTN 061 study, we examined participants' self-reported comfort with having condomless sex due to optimistic beliefs regarding HIV treatment. We assessed correlates of treatment optimism and its association with subsequent risk behaviors for HIV acquisition or transmission using multivariable logistic regression with generalized estimating equations. Independent correlates of treatment optimism included age ≥35 years, annual household income <$20,000, depressive symptoms, high HIV conspiracy beliefs, problematic alcohol use, and previous HIV diagnosis. Treatment optimism was independently associated with subsequent condomless anal sex with a male partner of serodiscordant/unknown HIV status among HIV-infected men, but this association was not statistically significant among HIV-uninfected men. HIV providers should engage men in counseling conversations to assess and minimize willingness to have condomless sex that is rooted in optimistic treatment beliefs without knowledge of viral suppression.

Naked mole-rat has increased translational fidelity compared with the mouse, as well as a unique 28S ribosomal RNA cleavage.

The naked mole-rat (Heterocephalus glaber) is a subterranean eusocial rodent with a markedly long lifespan and resistance to tumorigenesis. Multiple data implicate modulation of protein translation in longevity. Here we report that 28S ribosomal RNA (rRNA) of the naked mole-rat is processed into two smaller fragments of unequal size. The two breakpoints are located in the 28S rRNA divergent region 6 and excise a fragment of 263 nt. The excised fragment is unique to the naked mole-rat rRNA and does not show homology to other genomic regions. Because this hidden break site could alter ribosome structure, we investigated whether translation rate and amino acid incorporation fidelity were altered. We report that naked mole-rat fibroblasts have significantly increased translational fidelity despite having comparable translation rates with mouse fibroblasts. Although we cannot directly test whether the unique 28S rRNA structure contributes to the increased fidelity of translation, we speculate that it may change the folding or dynamics of the large ribosomal subunit, altering the rate of GTP hydrolysis and/or interaction of the large subunit with tRNA during accommodation, thus affecting the fidelity of protein synthesis. In summary, our results show that naked mole-rat cells produce fewer aberrant proteins, supporting the hypothesis that the more stable proteome of the naked mole-rat contributes to its longevity.

Dupilumab Safety and Efficacy up to 1 Year in Children Aged 6 Months to 5 Years with Atopic Dermatitis: Results from a Phase 3 Open-Label Extension Study.

BACKGROUND: Pediatric patients with moderate-to-severe atopic dermatitis (AD) often experience a high disease burden and have a high risk of persistent disease. Standard-of-care immunosuppressive systemic treatments have been used off-label for AD in pediatric patients despite concerns for suboptimal safety with continuous use and risk of relapse upon discontinuation. The biologic agent dupilumab is the first systemic treatment approved for moderate-to-severe AD in children as young as 6 months. Long-term safety and efficacy data in this patient population are needed to inform continuous AD management. OBJECTIVES: The purpose of this work was to determine the long-term safety and efficacy of dupilumab treatment up to 1 year in an open-label extension (OLE) study [LIBERTY AD PED-OLE (NCT02612454)] in children aged 6 months to 5 years with moderate-to-severe AD who previously participated in the 16-week, double-blind, phase 3 LIBERTY AD PRESCHOOL trial (NCT03346434 part B; parent study) and were subsequently enrolled in PED-OLE. METHODS: In PED-OLE, patients received dupilumab every 4 weeks according to a weight-tiered regimen (body weight ≥ 5 kg to < 15 kg: 200 mg; ≥ 15 kg to < 30 kg: 300 mg). RESULTS: Data for 142 patients were analyzed, 60 of whom had completed the 52-week visit at time of database lock. Mean age at baseline was 4.1 y [SD, 1.13; range, 1.0-5.9 years]. A majority (78.2%) of patients reported ≥ 1 treatment-emergent adverse event (TEAE), most of which were mild or moderate and transient. The most frequently reported TEAEs were nasopharyngitis (19.7%), cough (15.5%), and pyrexia (14.1%). One TEAE led to treatment discontinuation (severe urticaria, which resolved in 1 day). By week 52, 36.2% of patients had achieved an Investigator's Global Assessment score of 0/1 (clear/almost clear skin), and 96.6%, 79.3%, and 58.6% had at least 50%, 75%, or 90% improvement, respectively, in Eczema Area and Severity Index scores. CONCLUSIONS: Consistent with results seen in adults, adolescents, and older children (aged 6-11 years), treatment with dupilumab for up to 1 year in children aged 6 months to 5 years with inadequately controlled moderate-to-severe AD demonstrated an acceptable long-term safety profile and sustained efficacy. These results support the long-term continuous use of dupilumab in this patient population. TRIAL REGISTRATION: ClinicalTrials.gov Identifiers: NCT02612454 and NCT03346434 (part B).

Atopic dermatitis (AD) is a chronic inflammatory skin disease that often results in a high disease burden in young children and their families. Patients often need long-term treatment to control their disease symptoms, including itch and rash. Dupilumab treatment for 16 weeks has shown benefits in children aged 6 months to 5 years with moderate-to-severe AD, with an acceptable safety profile. As AD is likely to continue from childhood into adolescence and adulthood, there is a need for data supporting long-term use of dupilumab in young children. In this study, children who completed the 16-week study continued dupilumab treatment for up to 1 year, receiving 200 mg or 300 mg of dupilumab (depending on the child's bodyweight) every 4 weeks. Through the year of treatment, 78.2% of patients reported at least one side effect, most of which were mild or moderate. Only one patient interrupted treatment because of severe skin rash (hives), which was resolved in 1 day. At the end of the year, 36.2% of patients had clear or almost clear skin, and almost all (96.6%) achieved at least 50% improvement in their extent and severity of disease. Additionally, 79.3%, and 58.6% had at least 75% or 90% improvement in their extent and severity of disease. In summary, consistent with results seen in adults, adolescents, and older children, this study showed that 1-year dupilumab treatment provides continued benefits with an acceptable safety profile. These results support long-term continuous use of dupilumab in children aged 6 months to 5 years with moderate-to-severe AD. What is the long-term safety and efficacy profile in young children with moderate-to-severeatopic dermatitis treated with dupilumab?

To scan or not to scan: effect of scanning the axilla of all patients undergoing diagnostic breast ultrasound.

BACKGROUND: Breast ultrasonography is a useful modality in patients undergoing diagnostic and screening breast imaging. However, breast ultrasound has a high false positive rate and can be time-consuming to perform. PURPOSE: The purpose of this study was to evaluate the clinical impact of incidental axillary findings found on diagnostic breast ultrasounds at a single multi-site institution that has a standard protocol of scanning the axilla for all breast ultrasound exams. METHODS: All diagnostic breast ultrasounds were retrospectively reviewed from January 2017 to September 2019. Follow-up imaging, relevant clinical history, and pathology results were also reviewed. All positive axillary findings were divided into incidental or non-incidental findings depending on whether there was a direct clinical indication to scan the axilla. Descriptive statistics were performed with a 5% level of significance. RESULTS: Of the 19,695 diagnostic ultrasounds performed during this timeframe, there were 91 (0.5%) incidental axillary findings given a BIRADS category 3 or 4, and none of these findings resulted in the diagnosis of an occult breast cancer. One biopsy-proven SLL/CLL lymphoma was diagnosed that was otherwise clinically occult. CONCLUSION: Routine axillary scanning in all patients undergoing a diagnostic breast ultrasound at a large multi-site institution yields a low rate of incidental findings and has minimal impact on detection of cancer.

Perfusion Collateral Index versus Hypoperfusion Intensity Ratio in Assessment of Collaterals in Patients with Acute Ischemic Stroke.

BACKGROUND AND PURPOSE: Perfusion-based collateral indices such as the perfusion collateral index and the hypoperfusion intensity ratio have shown promise in the assessment of collaterals in patients with acute ischemic stroke. We aimed to compare the diagnostic performance of the perfusion collateral index and the hypoperfusion intensity ratio in collateral assessment compared with angiographic collaterals and outcome measures, including final infarct volume, infarct growth, and functional independence. MATERIALS AND METHODS: Consecutive patients with acute ischemic stroke with anterior circulation proximal arterial occlusion who underwent endovascular thrombectomy and had pre- and posttreatment MRI were included. Using pretreatment MR perfusion, we calculated the perfusion collateral index and the hypoperfusion intensity ratio for each patient. The angiographic collaterals obtained from DSA were dichotomized to sufficient (American Society of Interventional and Therapeutic Neuroradiology [ASITN] scale 3-4) versus insufficient (ASITN scale 0-2). The association of collateral status determined by the perfusion collateral index and the hypoperfusion intensity ratio was assessed against angiographic collaterals and outcome measures. RESULTS: A total of 98 patients met the inclusion criteria. Perfusion collateral index values were significantly higher in patients with sufficient angiographic collaterals (P < .001), while there was no significant (P = .46) difference in hypoperfusion intensity ratio values. Among patients with good (mRS 0-2) versus poor (mRS 3-6) functional outcome, the perfusion collateral index of ≥ 62 was present in 72% versus 31% (P = .003), while the hypoperfusion intensity ratio of ≤0.4 was present in 69% versus 56% (P = .52). The perfusion collateral index and the hypoperfusion intensity ratio were both significantly predictive of final infarct volume, but only the perfusion collateral index was significantly (P = .03) associated with infarct growth. CONCLUSIONS: Results show that the perfusion collateral index outperforms the hypoperfusion intensity ratio in the assessment of collateral status, infarct growth, and determination of functional outcomes.

CAST AWAY, a membrane-associated receptor-like kinase, inhibits organ abscission in Arabidopsis.

Receptor-like kinase-mediated cell signaling pathways play fundamental roles in many aspects of plant growth and development. A pair of Arabidopsis (Arabidopsis thaliana) leucine-rich repeat receptor-like kinases (LRR-RLKs), HAESA (HAE) and HAESA-LIKE2 (HSL2), have been shown to activate the cell separation process that leads to organ abscission. Another pair of LRR-RLKs, EVERSHED (EVR) and SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE1, act as inhibitors of abscission, potentially by modulating HAE/HSL2 activity. Cycling of these RLKs to and from the cell surface may be regulated by NEVERSHED (NEV), a membrane trafficking regulator that is essential for organ abscission. We report here the characterization of CAST AWAY (CST), a receptor-like cytoplasmic kinase that acts as a spatial inhibitor of cell separation. Disruption of CST suppresses the abscission defects of nev mutant flowers and restores the discrete identity of the trans-Golgi network in nev abscission zones. After organ shedding, enlarged abscission zones with obscured boundaries are found in nev cst flowers. We show that CST is a dual-specificity kinase in vitro and that myristoylation at its amino terminus promotes association with the plasma membrane. Using the bimolecular fluorescence complementation assay, we have detected interactions of CST with HAE and EVR at the plasma membrane of Arabidopsis protoplasts and hypothesize that CST negatively regulates cell separation signaling directly and indirectly. A model integrating the potential roles of receptor-like kinase signaling and membrane trafficking during organ separation is presented.

Exome Sequencing Identified Molecular Determinants of Retinal Dystrophies in Nine Consanguineous Pakistani Families.

Inherited retinal dystrophies (IRDs) are a heterogeneous group of degenerative disorders of the retina. Retinitis Pigmentosa (RP) is a common type of IRD that causes night blindness and loss of peripheral vision and may progress to blindness. Mutations in more than 300 genes have been associated with syndromic and non-syndromic IRDs. Recessive forms are more frequent in populations where endogamy is a social preference, such as Pakistan. The aim of this study was to identify molecular determinants of IRDs with the common presentation of night blindness in consanguineous Pakistani families. This study included nine consanguineous IRD-affected families that presented autosomal recessive inheritance of the night blindness phenotype. DNA was extracted from blood samples. Targeted exome sequencing of 344 known genes for retinal dystrophies was performed. Screening of nine affected families revealed two novel (c.5571_5576delinsCTAGATand c.471dup in EYS and SPATA7 genes, respectively) and six reported pathogenic mutations (c.304C>A, c.187C>T, c.1560C>A, c.547C>T, c.109del and c.9911_11550del in PDE6A, USH2A, USH2A, NMNAT1, PAX6 and ALMS1 genes, respectively) segregating with disease phenotype in each respective family. Molecular determinants of hereditary retinal dystrophies were identified in all screened families. Identification of novel variants aid future diagnosis of retinal dystrophies and help to provide genetic counseling to affected families.

Automated estimation of ischemic core volume on noncontrast-enhanced CT via machine learning.

BACKGROUND: Accurate estimation of ischemic core on baseline imaging has treatment implications in patients with acute ischemic stroke (AIS). Machine learning (ML) algorithms have shown promising results in estimating ischemic core using routine noncontrast computed tomography (NCCT). OBJECTIVE: We used an ML-trained algorithm to quantify ischemic core volume on NCCT in a comparative analysis to pretreatment magnetic resonance imaging (MRI) diffusion-weighted imaging (DWI) in patients with AIS. METHODS: Patients with AIS who had both pretreatment NCCT and MRI were enrolled. An automatic segmentation ML approach was applied using Brainomix software (Oxford, UK) to segment the ischemic voxels and calculate ischemic core volume on NCCT. Ischemic core volume was also calculated on baseline MRI DWI. Comparative analysis was performed using Bland-Altman plots and Pearson correlation. RESULTS: A total of 72 patients were included. The time-to-stroke onset time was 134.2/89.5 minutes (mean/median). The time difference between NCCT and MRI was 64.8/44.5 minutes (mean/median). In patients who presented within 1 hour from stroke onset, the ischemic core volumes were significantly (p = 0.005) underestimated by ML-NCCT. In patients presented beyond 1 hour, the ML-NCCT estimated ischemic core volumes approximated those obtained by MRI-DWI and with significant correlation (r = 0.56, p < 0.001). CONCLUSION: The ischemic core volumes calculated by the described ML approach on NCCT approximate those obtained by MRI in patients with AIS who present beyond 1 hour from stroke onset.

MR Angiography in Assessment of Collaterals in Patients with Acute Ischemic Stroke: A Comparative Analysis with Digital Subtraction Angiography.

Collateral status has prognostic and treatment implications in acute ischemic stroke (AIS) patients. Unlike CTA, grading collaterals on MRA is not well studied. We aimed to evaluate the accuracy of assessing collaterals on pretreatment MRA in AIS patients against DSA. AIS patients with anterior circulation proximal arterial occlusion with baseline MRA and subsequent endovascular treatment were included. MRA collaterals were evaluated by two neuroradiologists independently using the Tan and Maas scoring systems. DSA collaterals were evaluated by using the American Society of Interventional and Therapeutic Neuroradiology grading system and were used as the reference for comparative analysis against MRA. A total of 104 patients met the inclusion criteria (59 female, age (mean ± SD): 70.8 ± 18.1). The inter-rater agreement (k) for collateral scoring was 0.49, 95% CI 0.37-0.61 for the Tan score and 0.44, 95% CI 0.26-0.62 for the Maas score. Total number (%) of sufficient vs. insufficient collaterals based on DSA was 49 (47%) and 55 (53%) respectively. Using the Tan score, 45% of patients with sufficient collaterals and 64% with insufficient collaterals were correctly identified in comparison to DSA, resulting in a poor agreement (0.09, 95% CI 0.1-0.28). Using the Maas score, only 4% of patients with sufficient collaterals and 93% with insufficient collaterals were correctly identified against DSA, resulting in poor agreement (0.03, 95% CI 0.06-0.13). Pretreatment MRA in AIS patients has limited concordance with DSA when grading collaterals using the Tan and Maas scoring systems.

Emergence of erythromycin- and clindamycin-resistant Streptococcus pyogenes emm 90 strains in Hawaii.

We identified 12 erythromycin- and clindamycin-resistant emm 90 group A streptococcus (GAS) isolates during a retrospective invasive disease survey in Hawaii. A comparison with 20 type-matched isolates showed all resistant isolates to be emm 90.4b with the constitutive or inducible macrolide-lincosamide-streptogramin B resistance phenotype (cMLS(B) or iMLS(B)). All isolates had the same pulsed-field gel electrophoresis (PFGE) pattern, suggesting clonal spread.

Bactericidal In Vitro Activity of a Tissue-Achievable Concentration of Cefazolin against Methicillin-Resistant Staphylococcus aureus.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of skin and soft tissue infections and their recurrences. Although traditionally not considered for use against MRSA, cefazolin presents a possible option when administered using ultrasonic drug dispersion (UD2). This novel technique localizes delivery of drug into the subcutaneous tissue and achieves concentrations that exceed the minimum inhibitory concentrations (MICs) of most clinical MRSA isolates. The purpose of this study was to evaluate the impact of achievable cefazolin concentrations on the rate and extent of bactericidal activity using time-kill methodologies Materials and Methods: The cefazolin MICs of the four MRSA isolates selected for this in vitro time-kill study were 64, 128, 256, and 512 mg/L. Duplicates of drug-free control and cefazolin experiments were carried out using the average UD2-achievable cefazolin concentration (1,300 mg/L). Experiments were incubated at 37°C throughout each run. Samples were plated and incubated for 18 to 24 hours. The lower limit of detection of colony forming units per milliliter (CFU/mL) was 1.7 log10 CFU/mL. Cefazolin was considered bactericidal when it decreased bacterial density by ≥3 log10 CFU/mL from the initial inoculum after 24 hours of incubation. Results: Cefazolin produced mean 24-hour CFU changes of -4.39 to -4.89 log10 CFU/mL against MRSA isolates with MICs from 64 to 512 mg/L. Cefazolin demonstrated bactericidal activity against all studied MRSA isolates and no regrowth was observed at 24 hours. Conclusions: The mean cefazolin tissue concentration achieved by UD2 was bactericidal against four MRSA isolates. Further investigation is warranted to assess the utility of UD2-administered cefazolin against MRSA skin and soft tissue infections.