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54 result(s) for "Dave, Amanda M."
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Neonatal Hypoxic-Ischemic Brain Injury Alters Brain Acylcarnitine Levels in a Mouse Model
Hypoxic-ischemic brain injury (HIBI) leads to depletion of ATP, mitochondrial dysfunction, and enhanced oxidant formation. Measurement of acylcarnitines may provide insight into mitochondrial dysfunction. Plasma acylcarnitine levels are altered in neonates after an HIBI, but individual acylcarnitine levels in the brain have not been evaluated. Additionally, it is unknown if plasma acylcarnitines reflect brain acylcarnitine changes. In this study, postnatal day 9 CD1 mouse pups were randomized to HIBI induced by carotid artery ligation, followed by 30 min at 8% oxygen, or to sham surgery and normoxia, with subgroups for tissue collection at 30 min, 24 h, or 72 h after injury (12 animals/group). Plasma, liver, muscle, and brain (dissected into the cortex, cerebellum, and striatum/thalamus) tissues were collected for acylcarnitine analysis by LC-MS. At 30 min after HIBI, acylcarnitine levels were significantly increased, but the differences resolved by 24 h. Palmitoylcarnitine was increased in the cortex, muscle, and plasma, and stearoylcarnitine in the cortex, striatum/thalamus, and cerebellum. Other acylcarnitines were elevated only in the muscle and plasma. In conclusion, although plasma acylcarnitine results in this study mimic those seen previously in humans, our data suggest that the plasma acylcarnitine profile was more reflective of muscle changes than brain changes. Acylcarnitine metabolism may be a target for therapeutic intervention after neonatal HIBI, though the lack of change after 30 min suggests a limited therapeutic window.
Cholesterol metabolism and brain injury in neonatal encephalopathy
Neonatal encephalopathy (NE) results from impaired cerebral blood flow and oxygen delivery to the brain. The pathophysiology of NE is complex and our understanding of its underlying pathways continues to evolve. There is considerable evidence that cholesterol dysregulation is involved in several adult diseases, including traumatic brain injury, stroke, Huntington’s disease, and Parkinson’s disease. Although the research is less robust in pediatrics, there is emerging evidence that aberrations in cholesterol metabolism may also be involved in the pathophysiology of neonatal NE. This narrative review provides an overview of cholesterol metabolism in the brain along with several examples from the adult literature where pathologic alterations in cholesterol metabolism have been associated with inflammatory and ischemic brain injury. Using those data as a background, the review then discusses the current preclinical data supporting the involvement of cholesterol in the pathogenesis of NE as well as how brain-specific cholesterol metabolites may serve as serum biomarkers for brain injury. Lastly, we review the potential for using the cholesterol metabolic pathways as therapeutic targets. Further investigation of the shifts in cholesterol synthesis and metabolism after hypoxia–ischemia may prove vital in understanding NE pathophysiology as well as providing opportunities for rapid diagnosis and therapeutic interventions. Impact This review summarizes emerging evidence that aberrations in cholesterol metabolism may be involved in the pathophysiology of NE. Using data from NE as well as analogous adult disease states, this article reviews the potential for using cholesterol pathways as targets for developing novel therapeutic interventions and using cholesterol metabolites as biomarkers for injury. When possible, gaps in the current literature were identified to aid in the development of future studies to further investigate the interactions between cholesterol pathways and NE.
The Impact of Prematurity at Birth on Short-Term Postoperative Outcomes Following Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis
Prematurity is associated with surgical complications. This study sought to determine the risk of prematurity on 30-day complications, reoperations, and readmissions following ≥7-level PSF for AIS which has not been established. Utilizing the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP)-Pediatric dataset, all AIS patients undergoing ≥7-level PSF from 2012–2016 were identified. Cases were 1:1 propensity score-matched to controls by age, sex, and number of spinal levels fused. Prematurity sub-classifications were also evaluated: extremely (<28 weeks), very (28–31 weeks), and moderate-to-late (32–36 weeks) premature. Univariate analysis with post hoc Bonferroni compared demographics, hospital parameters, and 30-day outcomes. Multivariate logistic regression identified independent predictors of adverse 30-day outcomes. 5531 patients (term = 5099; moderate-to-late premature = 250; very premature = 101; extremely premature = 81) were included. Premature patients had higher baseline rates of multiple individual comorbidities, longer mean length of stay, and higher 30-day readmissions and infections than the term cohort. Thirty-day readmissions increased with increasing prematurity. Very premature birth predicted UTIs, superficial SSI/wound dehiscence, and any infection, and moderate-to-late premature birth predicted renal insufficiency, deep space infections, and any infection. Prematurity of AIS patients differentially impacted rates of 30-day adverse outcomes following ≥7-level PSF. These results can guide preoperative optimization and postoperative expectations.
A 39-Year-Old Pregnant Woman with Pulmonary Emboli on Long Term Anticoagulation
We present the case of a 39-year-old pregnant woman with Klippel-Trenaunay syndrome (KTS). We demonstrate the risks of multiple, co-existing pro-thrombotic states (pregnancy, KTS), discuss complications of KTS (deep venous thromboembolisms and pulmonary emboli) and highlight general and disease-specific preventive measures against venous thromboembolic events (VTE). KTS is a rare condition and it's co-existence with pregnancy and VTEs is rarer still.
Verification of Diagnosis in Tuberculosis: A Case Report and Discussion
Tuberculosis (TB), caused by strains of Mycobacterium tuberculosis complex (M. tuberculosis), is a pulmonary infection that is spread by airborne droplet transmission. The development and spread of drug-resistant strains of M. tuberculosisgreatly jeopardize TB control efforts. We report the case of a previously healthy 43-year-old male, visiting from China, who presented to the emergency department complaining of hemoptysis of 10 days' duration. Cultures were positive for acid fast bacteria and negative for fungi. M. tuberculosis infection was confirmed by a deoxyribonucleic acid (DNA) probe. The patient was initially started on first-line therapy of isoniazid, rifampin, pyrazinamide, and ethambutol, with pyridoxine. His country of origin, China, increased suspicion for drug-resistant tuberculosis. Two weeks later, susceptibility testing of the M. tuberculosis isolate showed resistance to isoniazid, pyrazinamide, and ethambutol. Therapy was subsequently changed to amikacin, linezolid, moxifloxacin, and rifampin. The isolate was subsequently sent to the Center for Disease Control (CDC) for evaluation. Repeat testing showed that the isolate was susceptible to rifampin, pyrazinamide, and ethambutol. The patient was then restarted on his initial anti-TB regimen and was able to return to China. The main goals for the treatment of TB are to treat the individual patient and to minimize transmission. Clues that point to the possibility of multiple drug resistant tuberculosis (MDR-TB) include contact with a patient with MDR-TB, origin from an endemic region, or failure of therapy with documented supervision. Collaboration with experts was imperative in ensuring appropriate patient care.
CATMoS: Collaborative Acute Toxicity Modeling Suite
Humans are exposed to tens of thousands of chemical substances that need to be assessed for their potential toxicity. Acute systemic toxicity testing serves as the basis for regulatory hazard classification, labeling, and risk management. However, it is cost- and time-prohibitive to evaluate all new and existing chemicals using traditional rodent acute toxicity tests. models built using existing data facilitate rapid acute toxicity predictions without using animals. The U.S. Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM) Acute Toxicity Workgroup organized an international collaboration to develop models for predicting acute oral toxicity based on five different end points: Lethal Dose 50 ( value, U.S. Environmental Protection Agency hazard (four) categories, Globally Harmonized System for Classification and Labeling hazard (five) categories, very toxic chemicals [ ( )], and nontoxic chemicals ( ). An acute oral toxicity data inventory for 11,992 chemicals was compiled, split into training and evaluation sets, and made available to 35 participating international research groups that submitted a total of 139 predictive models. Predictions that fell within the applicability domains of the submitted models were evaluated using external validation sets. These were then combined into consensus models to leverage strengths of individual approaches. The resulting consensus predictions, which leverage the collective strengths of each individual model, form the Collaborative Acute Toxicity Modeling Suite (CATMoS). CATMoS demonstrated high performance in terms of accuracy and robustness when compared with results. CATMoS is being evaluated by regulatory agencies for its utility and applicability as a potential replacement for rat acute oral toxicity studies. CATMoS predictions for more than 800,000 chemicals have been made available via the National Toxicology Program's Integrated Chemical Environment tools and data sets (ice.ntp.niehs.nih.gov). The models are also implemented in a free, standalone, open-source tool, OPERA, which allows predictions of new and untested chemicals to be made. https://doi.org/10.1289/EHP8495.
Increase in anthelmintic resistance in sheep flocks in Ireland
Gastrointestinal nematode (GIN) infection is widespread in grazing lambs in Ireland, with heavy infections resulting in ill-thrift and ill-health. Control is currently dependent on the use of broad-spectrum anthelmintics. However, both anthelmintic resistance (AR) and treatment failure have been reported in Irish flocks. Most recent reports have determined the rate of treatment failure. Therefore, to ascertain the level of AR on sheep farms in Ireland 77 faecal egg count reduction tests (FECRT) were carried out on 24 farms between 2018 and 2023 with the test repeated on 3 farms in another year. Resistance was widespread, with all farms showing evidence of resistance to benzimidazoles. For levamisole, 50% of farms evidenced susceptibility and 42% resistance; the remaining 2 farms had conflicting results in different years. For the macrocyclic lactone, ivermectin, susceptibility was found on 25% of farms and resistance on 71%. The remaining farm had conflicting results in different years. Moxidectin was tested on 3 farms and all 3 showed evidence of resistance. For a small number of tests larvae were identified to genus level pre- and post-treatment. The predominant genus post-treatment was Teladorsagia circumcincta although Trichostrongylus spp. and Cooperia spp. were also identified. Overall, AR in GIN was widespread on sheep farms in Ireland and the adoption of sustainable parasite control practices that reduces reliance on anthelmintics is imperative. The finding of conflicting results in different years highlights the importance of regular monitoring for AR and the need to incorporate GIN species identification into the FECRT to enable species-specific efficacy calculation.
Integrating de novo and inherited variants in 42,607 autism cases identifies mutations in new moderate-risk genes
To capture the full spectrum of genetic risk for autism, we performed a two-stage analysis of rare de novo and inherited coding variants in 42,607 autism cases, including 35,130 new cases recruited online by SPARK. We identified 60 genes with exome-wide significance ( P  < 2.5 × 10 −6 ), including five new risk genes ( NAV3 , ITSN1 , MARK2 , SCAF1 and HNRNPUL2 ). The association of NAV3 with autism risk is primarily driven by rare inherited loss-of-function (LoF) variants, with an estimated relative risk of 4, consistent with moderate effect. Autistic individuals with LoF variants in the four moderate-risk genes ( NAV3 , ITSN1 , SCAF1 and HNRNPUL2 ; n  = 95) have less cognitive impairment than 129 autistic individuals with LoF variants in highly penetrant genes ( CHD8, SCN2A, ADNP, FOXP1 and SHANK3 ) (59% vs 88%, P  = 1.9 × 10 −6 ). Power calculations suggest that much larger numbers of autism cases are needed to identify additional moderate-risk genes. An integrated analysis of de novo and inherited coding variants in 42,607 individuals with autism spectrum disorder identifies 60 risk genes of which five have not previously been associated with neurodevelopmental disorders.
Parasitaemia data and molecular characterization of Haemoproteus catharti from New World vultures (Cathartidae) reveals a novel clade of Haemosporida
Background New World vultures (Cathartiformes: Cathartidae) are obligate scavengers comprised of seven species in five genera throughout the Americas. Of these, turkey vultures ( Cathartes aura ) and black vultures ( Coragyps atratus ) are the most widespread and, although ecologically similar, have evolved differences in morphology, physiology, and behaviour. Three species of haemosporidians have been reported in New World vultures to date: Haemoproteus catharti , Leucocytozoon toddi and Plasmodium elongatum , although few studies have investigated haemosporidian parasites in this important group of species. In this study, morphological and molecular methods were used to investigate the epidemiology and molecular biology of haemosporidian parasites of New World vultures in North America. Methods Blood and/or tissue samples were obtained from 162 turkey vultures and 95 black vultures in six states of the USA. Parasites were identified based on their morphology in blood smears, and sequences of the mitochondrial cytochrome b and nuclear adenylosuccinate lyase genes were obtained for molecular characterization. Results No parasites were detected in black vultures, whereas 24% of turkey vultures across all sampling locations were positive for H. catharti by blood smear analysis and/or PCR testing. The phylogenetic analysis of cytochrome b gene sequences revealed that H. catharti is closely related to MYCAMH1, a yet unidentified haemosporidian from wood storks ( Mycteria americana ) in southeastern USA and northern Brazil. Haemoproteus catharti and MYCAMH1 represent a clade that is unmistakably separate from all other Haemoproteus spp., being most closely related to Haemocystidium spp. from reptiles and to Plasmodium spp. from birds and reptiles. Conclusions Haemoproteus catharti is a widely-distributed parasite of turkey vultures in North America that is evolutionarily distinct from other haemosporidian parasites. These results reveal that the genetic diversity and evolutionary relationships of avian haemosporidians are still being uncovered, and future studies combining a comprehensive evaluation of morphological and life cycle characteristics with the analysis of multiple nuclear and mitochondrial genes will be useful to redefine the genus boundaries of these parasites and to re-evaluate the relationships amongst haemosporidians of birds, reptiles and mammals.
Global assessment of marine plastic exposure risk for oceanic birds
Plastic pollution is distributed patchily around the world’s oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species.