Structure and topography of the synaptic V-ATPase-synaptophysin complex.

Synaptic vesicles are organelles with a precisely defined protein and lipid composition1,2, yet the molecular mechanisms for the biogenesis of synaptic vesicles are mainly unknown. Here, we discovered a well-defined interface between the synaptic vesicle V-ATPase and synaptophysin by in situ cryo-electron tomography and single particle cryo-electron microscopy of functional synaptic vesicles isolated from mouse brains3. The synaptic vesicle V-ATPase is an ATP-dependent proton pump that establishes the protein gradient across the synaptic vesicle, which in turn drives the uptake of neurotransmitters4,5. Synaptophysin6 and its paralogs synaptoporin7 and synaptogyrin8 belong to a family of abundant synaptic vesicle proteins whose function is still unclear. We performed structural and functional studies of synaptophysin knockout mice, confirming the identity of synaptophysin as an interaction partner with the V-ATPase. Although there is little change in the conformation of the V-ATPase upon interaction with synaptophysin, the presence of synaptophysin in synaptic vesicles profoundly affects the copy number of V-ATPases. This effect on the topography of synaptic vesicles suggests that synaptophysin assists in their biogenesis. In support of this model, we observed that synaptophysin knockout mice exhibit severe seizure susceptibility, suggesting an imbalance of neurotransmitter release as a physiological consequence of the absence of synaptophysin.

Correction: Blanco et al. Synthesis and Characterization of [Fe(Htrz)2(trz)](BF4)] Nanocubes. Molecules 2022, 27, 1213.

After publication of the paper [...].

Pyogenic flexor tenosynovitis due to Kingella kingae in an infant.

Pyogenic flexor tenosynovitis is relatively common but is seldom reported in young children. Kingella kingae is increasingly recognised as a causative agent. We report on an infant who presented with a palmar deep space infection and pyogenic flexor tenosynovitis caused by K. kingae K. kingae is a fastidious, often culture-negative, organism which has been increasingly recognised as a cause of paediatric orthopaedic infections, including flexor tenosynovitis. Clinical suspicion should be heightened, and antibiotic coverage broadened in the setting of a positive physical examination and negative blood cultures.

Performing an ovariohysterectomy at the time of c-section does not pose an increase in risk of mortality, intra- or postoperative complications, or decreased mothering ability of the bitch.

OBJECTIVE: Ovariohysterectomy (OVH) is frequently recommended at the time of c-section in canines, yet prior literature suggests poor mothering ability and increased morbidity to the bitch with c-section with concurrent OVH (CSOVH). The study objective was to compare maternal survival, complications, and mothering ability between bitches that underwent c-section alone (CS) or CSOVH. ANIMALS: 125 bitches. PROCEDURES: Medical records from 2014 through 2021 were retrospectively reviewed; owners were surveyed for information up to weaning. RESULTS: 80 bitches undergoing CS and 45 bitches undergoing CSOVH were identified. There was no difference in anesthesia duration, intraoperative complications, postoperative complications, mothering ability, puppy survival to weaning, or other variables compared between groups. CSOVH bitches had longer surgery times (P = .045; 54.4 ± 20.7 min vs 46.9 ± 16.6 min) and longer time from delivery to nursing (P = .028; 75.4 ± 22.3 min vs 65.2 ± 19.5 min). Ninety (72%) owners responded to the survey. All 90 bitches survived until puppy weaning. CSOVH bitches were more frequently perceived as painful postoperatively (P = .015). CLINICAL RELEVANCE: Performing an OVH at the time of c-section does not pose a significant increase in risk of mortality, intraoperative complications, postoperative complications, or decreased mothering ability of the bitch. The increased duration of surgery and increased time from delivery to nursing in the CSOVH group were clinically insignificant. Appropriate postoperative pain management should be emphasized post-CSOVH. Based on these results, OVH should be performed concurrently with c-section if indicated.

Magnetic Ordering in a High-Spin Donor-Acceptor Conjugated Polymer.

The development of open-shell organic molecules that magnetically order at room temperature,which can be practically applied, remains a grand challenge in chemistry, physics, and materials science. Despite the exploration of vast chemical space, design paradigms for organic paramagnetic centers generally result in unpaired electron spins that are unstable or isotropic. Here, a high-spin conjugated polymer is demonstrated, which is composed of alternating cyclopentadithiophene and benzo[1,2-c;4,5-c']bis[1,2,5]thiadiazole heterocycles, in which macromolecular structure and topology coalesce to promote the spin center generation and intermolecular exchange coupling. Electron paramagnetic resonance (EPR) spectroscopy is consistent with spatially localized spins, while magnetic susceptibility measurements show clear anisotropic spin ordering and exchange interactions that persist at room temperature. The application of long-range π-correlations for spin center generation promotes remarkable stability. This work offers a fundamentally new approach to the implementation of this long-sought-after physical phenomenon within organic materials and the integration of manifold properties within emerging technologies.

Risk factors for neonatal mortality prior to hospital discharge in brachycephalic and nonbrachycephalic dogs undergoing cesarean section.

OBJECTIVES: To compare neonatal survival to discharge rates between brachycephalic and nonbrachycephalic dogs undergoing cesarean section (c-section) and identify risk factors for neonatal mortality. STUDY DESIGN: Retrospective study. ANIMALS OR SAMPLE POPULATION: A total of 480 puppies from 90 bitches undergoing 106 c-sections. METHODS: Medical records of c-sections performed between January 2012 and September 2021 were reviewed. Data collected included brachycephalic versus nonbrachycephalic breed, elective versus emergency c-section, litter size (c-section and total [including those born prior to and via c-section]), and neonatal survival to discharge. A generalized linear mixed model (univariable and multivariable) was performed to evaluate variables versus neonatal survival. RESULTS: Overall neonatal survival to discharge was 93.1% (447/480); survival was similar between brachycephalic and nonbrachycephalic breeds (p = .221, 202/213 [94.8%] brachycephalic survival, 245/267 [91.8%] nonbrachycephalic survival). Puppies delivered via elective c-section were more likely to survive compared to emergency c-section (p < .001, 238/240 [99.2%] elective survival, 209/240 [87.1%] emergency survival). Puppies delivered in larger c-section litters were more likely to survive (p < .004) compared to smaller litters. Total litter size had no effect on survival. CONCLUSION: Brachycephalism had no effect on neonatal survival. Puppies delivered via elective c-section were more likely to survive compared to puppies delivered via emergency c-section. CLINICAL SIGNIFICANCE: Outcomes following c-section are similar between brachycephalic and nonbrachycephalic breeds. While it is preferable to encourage selective breeding for bitches that are able to whelp naturally, elective c-section should be considered in bitches at high risk for dystocia to maximize neonatal survival.

Synthesis and Characterization of [Fe(Htrz)2(trz)](BF4)] Nanocubes.

Compounds that exhibit spin-crossover (SCO) type behavior have been extensively investigated due to their ability to act as molecular switches. Depending on the coordinating ligand, in this case 1H-1,2,4-triazole, and the crystallite size of the SCO compound produced, the energy requirement for the spin state transition can vary. Here, SCO [Fe(Htrz)2(trz)](BF4)] nanoparticles were synthesized using modified reverse micelle methods. Reaction conditions and reagent ratios are strictly controlled to produce nanocubes of 40-50 nm in size. Decreases in energy requirements are seen in both thermal and magnetic transitions for the smaller sized crystallites, where, compared to bulk materials, a decrease of as much as 20 °C can be seen in low to high spin state transitions.

Epidemiology and Outcomes of Patients With Healthcare Facility-Onset Clostridioides difficile Infection.

BACKGROUND: Clostridioides difficile infection (CDI) has become a rising public health threat. Our study aims to characterize the epidemiology and measure the attributable cost, length of stay, and in-hospital mortality of healthcare facility-onset Clostridioides difficile infection (HO-CDI) among patients in the U.S. Military Health System (MHS). METHODS: We performed a case-control and cross-sectional inpatient study of HO-CDI using MHS database billing records. Cases included those who were at least 18 years of age admitted to a military treatment facility with a stool sample positive for C. difficile obtained >3 days after admission. Risk factors in the preceding year were identified. Patient case-mix adjusted outcomes including in-hospital mortality, length of stay, and hospitalization cost were evaluated by high-dimensional propensity score adjusted logistic regression. RESULTS: Among 474,518 admissions within the MHS from 2008 to 2015, we identified 591 (0.12%) patients with HO-CDI and found a significant increase in the trend of HO-CDI over the 7-year study period (P < .001). Patients with HO-CDI had significantly higher hospitalization cost (attributable difference $66,044, P < .001), prolonged hospital stay (attributable difference 12.4 days, P < 0.001), and increased odds of in-hospital mortality (case-mix adjusted odds ratio 1.98; 95% CI, 1.43-2.74). CONCLUSIONS: Healthcare facility-onset Clostridioides difficile infection is rising in patients within the MHS and is associated with increased length of stay, hospital costs, and in-hospital mortality. We identified a significantly increased burden of hospitalization among patients admitted with HO-CDI, highlighting the importance of infection control and antimicrobial stewardship initiatives aimed at decreasing the spread of this pathogen.

Community-Associated Clostridioides difficile Infection in Children: A Review of Recent Literature.

Clostridioides difficile infection (CDI) in children is more often acquired in the community than in the hospital. Community-associated Clostridioides difficile infection (CA-CDI) cases seem to be rising, although this is confounded by the unclear role of C. difficile in children 1 and 3 years of age and overreliance on nucleic acid amplification tests for diagnosis. Exposure to antibiotics, acid suppression medications, health care settings, and close contacts with CDI are associated with CA-CDI in children. These infections are more common in children with chronic medical conditions, especially those involving the gastrointestinal tract and immune suppression. Most CA-CDI in children are mild and managed in the outpatient setting, but a small subset requires hospitalization and can be quite severe. Approximately 10% of children with CA-CDI experience a recurrence. Infection control guidance focuses on the hospital setting and future studies on the best methods for preventing community spread of C. difficile are needed.

Epidemiology and Outcomes of Vancomycin-Resistant Enterococcus Infections in the U.S. Military Health System.

INTRODUCTION: Vancomycin-resistant enterococci (VRE) are classified by the Centers for Diseases Control and Prevention as a serious antibiotic resistance threat. Our study aims to characterize the epidemiology, associated conditions, and outcomes of VRE infections among hospitalized patients in the U.S. military health system (MHS). MATERIALS AND METHODS: We performed a retrospective cohort study of patients with VRE infection using the MHS database. Cases included all patients admitted to a military treatment facility for ≥2 days from October 2008 to September 2015 with a clinical culture growing Enterococcus faecalis, Enterococcus faecium, or Enterococcus species (unspecified), reported as resistant to vancomycin. Co-morbid conditions and procedures associated with VRE infection were identified by multivariable conditional logistic regression. Patient case-mix adjusted outcomes including in-hospital mortality, length of stay, and hospitalization cost were evaluated by high-dimensional propensity score adjustment. RESULTS: During the seven-year study period and among 1,161,335 hospitalized patients within the MHS, we identified 577 (0.05%) patients with VRE infection. A majority of VRE infections were urinary tract infections (57.7%), followed by bloodstream (24.7%), other site/device-related (12.9%), respiratory (2.9%), and wound infections (1.8%). Risk factors for VRE infection included invasive gastrointestinal, pulmonary, and urologic procedures, indwelling devices, and exposure to 4th generation cephalosporins, but not to glycopeptides. Patients hospitalized with VRE infection had significantly higher hospitalization costs (attributable difference [AD] $135,534, P<0.001), prolonged hospital stays (AD 20.44 days, P<0.001, and higher in-hospital mortality (case-mix adjusted odds ratio 5.77; 95% confidence interval 4.59-7.25). CONCLUSIONS: VRE infections carry a considerable burden for hospitalized patients given their impact on length of stay, hospitalization costs, and in-hospital mortality. Active surveillance and infection control efforts should target those identified as high-risk for VRE infection. Antimicrobial stewardship programs should focus on limiting exposure to 4th generation cephalosporins.

Evaluation of HIV-1 neutralizing and binding antibodies in maternal-infant transmission in Thailand.

Despite anti-retroviral therapy (ART) interventions for HIV+ pregnant mothers, over 43,000 perinatal infections occur yearly. Understanding risk factors that lead to mother-to-child transmission (MTCT) of HIV are critical. We evaluated maternal and infant plasma binding and neutralizing antibody responses in a drug-naïve, CRF01_AE infected MTCT cohort from Thailand to determine associations with transmission risk. Env V3-specific IgG and neutralizing antibody responses were significantly higher in HIV- infants, as compared to HIV+ infants. In fact, infant plasma neutralizing antibodies significantly associated with non-transmission. Conversely, increased maternal Env V3-specific IgG and neutralizing antibody responses were significantly associated with increased transmission risk, after controlling for maternal viral load. Our results highlight the importance of evaluating both maternal and infant humoral immune responses to better understand mechanisms of protection, as selective placental antibody transport may have a role in MTCT. This study further emphasizes the complex role of Env-specific antibodies in MTCT of CRF01_AE HIV.

Clinical characteristics, risk factors, and outcomes of patients hospitalized in the US military health system with carbapenem-resistant Enterobacteriaceae infection.

BACKGROUND: We aimed to characterize the epidemiology, identify risk factors, and measure outcomes of carbapenem-resistant Enterobacteriaceae (CRE) infections among hospitalized patients. METHODS: We performed a retrospective study of hospitalized patients with CRE infection using records from the US military health system database. Cases included patients admitted for ≥2 days from 2008-2015, with a clinical culture growing any Enterobacteriaceae reported as resistant to a carbapenem. Multivariable logistic regression was used to identify comorbid conditions and procedures associated with CRE infection, and a high-dimensional propensity score was used for a case-mix adjusted evaluation of CRE-associated in-hospital mortality, length of stay, and hospitalization costs. RESULTS: From 1,162,686 hospitalized patients, we identified 143 with CRE infection over the 7-year study period. Conditions associated with CRE infection included manipulation of the gastrointestinal tract, musculoskeletal trauma, orthopedic procedures, septicemia, and both recent and remote exposure to broad-spectrum ß-lactam antibiotics. Patients hospitalized with CRE infection had significantly higher hospitalization costs (attributable difference, $206,664; P < .001), longer hospital stays (attributable difference, 28.8 days; P < .001), and increased odds of in-hospital mortality (adjusted odds ratio, 3.34; 95% confidence interval, 1.82-6.12). CONCLUSIONS: CRE are a significant threat to hospitalized patients. Our study quantifies the health care burden associated with CRE infection in the inpatient setting and highlights the importance of initiatives aimed at curbing the spread of these costly infections.

Inflammatory markers limitations in the diagnosis of pediatric calcaneal osteomyelitis.

Calcaneal osteomyelitis is an uncommon, but clinically important emergent condition in the differential of the limping child. Early recognition is paramount to prevent complications from delayed diagnosis like formation of periosteal abscesses or growth plate injury. The diagnosis of pediatric osteoarticular infection relies on a combination of clinical exam, imaging and inflammatory markers. Erythrocyte sedation rate (ESR) and C-reactive protein (CRP) have reported sensitivities for osteomyelitis of 94% and 95%, respectively. However, clinicians should be aware that certain clinical factors can decrease the reliability of inflammatory markers in this pediatric condition. Location of infection in small bones like the calcaneus can lead to significantly lower sensitivities than in long bones. Pretreatment with antibiotics prior presentation can also decrease the reliability of ESR and CRP. In this case, we highlight two unique clinical factors that diminish the sensitivity of commonly used inflammatory markers in the diagnosis of pediatric osteomyelitis.

Using multidimensional item response theory to evaluate how response styles impact measurement.

Multidimensional item response theory (MIRT) models for response style (e.g., Bolt, Lu, & Kim, 2014, Psychological Methods, 19, 528; Falk & Cai, 2016, Psychological Methods, 21, 328) provide flexibility in accommodating various response styles, but often present difficulty in isolating the effects of response style(s) from the intended substantive trait(s). In the presence of such measurement limitations, we consider several ways in which MIRT models are nevertheless useful in lending insight into how response styles may interfere with measurement for a given test instrument. Such a study can also inform whether alternative design considerations (e.g., anchoring vignettes, self-report items of heterogeneous content) that seek to control for response style effects may be helpful. We illustrate several aspects of an MIRT approach using real and simulated analyses.

Ingesting Self-Grown Produce and Seropositivity for Hepatitis E in the United States.

BACKGROUND: Hepatitis E virus (HEV) is a major cause of hepatitis in developing and industrialized countries worldwide. The modes of HEV transmission in industrialized countries, including the United States, remain largely unknown. This study is aimed at evaluating the association between HEV seropositivity and consumption of self-grown foods in the United States. METHODS: Cross-sectional data was extracted from the 2009-2012 National Health and Nutrition Examination Survey (NHANES). Data from the dietary interview and the serum HEV IgG and IgM enzyme immunoassay test results were linked and examined. Univariate and multivariable logistic regression models were used to evaluate the significance and effect size of an association between self-grown food consumption and hepatitis E seropositivity. RESULTS: The estimated HEV seroprevalence in the civilian, noninstitutionalized US population was 6.6% in 2009-2012, which corresponds to an estimated hepatitis E national seroprevalence of 17,196,457 people. Overall, 10.9% of participants who ingested self-grown foods had positive HEV antibodies versus 6.1% of participants who did not consume self-grown foods (P < 0.001; odds ratio (OR) 1.87; 95% CI 1.41-2.48). In the age-stratified multivariable analysis, the correlation between ingesting self-grown foods and HEV seropositivity was significant for participants 40-59 years old, but not overall, or for those < 40 years or ≥60 years. CONCLUSIONS: Ingesting self-grown food, or simply the process of gardening/farming, may be a source of zoonotic HEV transmission.

Renal cell carcinoma in a cat with polycystic kidney disease undergoing renal transplantation.

CASE SUMMARY: A 10-year-old spayed female American Shorthair cat underwent renal transplantation due to worsening chronic kidney disease secondary to polycystic kidney disease. During transplantation, the right kidney grossly appeared to be more diseased than the left and was firmly adhered to the surrounding tissues. An intraoperative fine-needle aspirate of the right native kidney revealed inflammatory cells but no evidence of neoplasia. To create space for the allograft, a right nephrectomy was performed. Following nephrectomy, the right native kidney was submitted for biopsy. Biopsy results revealed a renal cell carcinoma. Although the cat initially recovered well from surgery, delayed graft function was a concern in the early postoperative period. Significant azotemia persisted and the cat began to have diarrhea. Erythematous skin lesions developed in the perineal and inguinal regions, which were suspected to be secondary to thromboembolic disease based on histopathology. The cat's clinical status continued to decline with development of signs of sepsis, followed by marked obtundation with uncontrollable seizures. Given the postoperative diagnosis of renal cell carcinoma and the cat's progressively declining clinical status, humane euthanasia was elected. RELEVANCE AND NOVEL INFORMATION: This case is the first to document renal cell carcinoma in a cat with polycystic kidney disease. An association of the two diseases has been reported in the human literature, but such a link has yet to be described in veterinary medicine. Given the association reported in the human literature, a plausible relationship between polycystic kidney disease and renal cell carcinoma in cats merits further investigation.

Identification of the primary peptide contaminant that inhibits fibrillation and toxicity in synthetic amyloid-ß42.

Understanding the pathophysiology of Alzheimer disease has relied upon the use of amyloid peptides from a variety of sources, but most predominantly synthetic peptides produced using t-butyloxycarbonyl (Boc) or 9-fluorenylmethoxycarbonyl (Fmoc) chemistry. These synthetic methods can lead to minor impurities which can have profound effects on the biological activity of amyloid peptides. Here we used a combination of cytotoxicity assays, fibrillation assays and high resolution mass spectrometry (MS) to identify impurities in synthetic amyloid preparations that inhibit both cytotoxicity and aggregation. We identify the Aß42Δ39 species as the major peptide contaminant responsible for limiting both cytotoxicity and fibrillation of the amyloid peptide. In addition, we demonstrate that the presence of this minor impurity inhibits the formation of a stable Aß42 dimer observable by MS in very pure peptide samples. These results highlight the critical importance of purity and provenance of amyloid peptides in Alzheimer's research in particular, and biological research in general.

Risk Factors for Community-Associated Clostridium difficile Infection in Children.

OBJECTIVE: To characterize the medication and other exposures associated with pediatric community-associated Clostridium difficile infections (CA-CDIs). STUDY DESIGN: We performed a case-control study using billing records from the US military health system database. CA-CDI cases included children 1-18 years of age with an outpatient International Classification of Diseases, Ninth Revision, Clinical Modification diagnostic code for Clostridium difficile infection (CDI) from 2001 to 2013. Each case was matched to 3 controls without CDI by age and sex. Children hospitalized at any time before their CDI were excluded. Outpatient pharmacy records were used to identify medication exposures in the preceding 12 weeks. In addition, we evaluated recent outpatient healthcare exposure, exposure to a sibling younger than 1 year of age, or to a family member with CDI. RESULTS: A total of 1331 children with CA-CDI were identified and 3993 controls were matched successfully. Recent exposure to fluoroquinolones, clindamycin (OR 73.00; 95% CI 13.85-384.68), third-generation cephalosporins (OR 16.32; 95% CI 9.11-29.26), proton pump inhibitors (OR 8.17; 95% CI 2.35-28.38), and to multiple classes of antibiotics, each was associated strongly the subsequent diagnosis of CA-CDI. Recent exposure to outpatient healthcare clinics (OR 1.35; 95% CI 1.31-1.39) or to a family member with CDI also was associated with CA-CDI. CONCLUSIONS: CA-CDI is associated with medications regularly prescribed in pediatric practice, along with exposure to outpatient healthcare clinics and family members with CDI. Our findings provide additional support for the judicious use of these medications and for efforts to limit spread of CDI in ambulatory healthcare settings and households.