Streptothricin F is a bactericidal antibiotic effective against highly drug-resistant gram-negative bacteria that interacts with the 30S subunit of the 70S ribosome.

The streptothricin natural product mixture (also known as nourseothricin) was discovered in the early 1940s, generating intense initial interest because of excellent gram-negative activity. Here, we establish the activity spectrum of nourseothricin and its main components, streptothricin F (S-F, 1 lysine) and streptothricin D (S-D, 3 lysines), purified to homogeneity, against highly drug-resistant, carbapenem-resistant Enterobacterales (CRE) and Acinetobacter baumannii. For CRE, the MIC50 and MIC90 for S-F and S-D were 2 and 4 µM, and 0.25 and 0.5 µM, respectively. S-F and nourseothricin showed rapid, bactericidal activity. S-F and S-D both showed approximately 40-fold greater selectivity for prokaryotic than eukaryotic ribosomes in in vitro translation assays. In vivo, delayed renal toxicity occurred at >10-fold higher doses of S-F compared with S-D. Substantial treatment effect of S-F in the murine thigh model was observed against the otherwise pandrug-resistant, NDM-1-expressing Klebsiella pneumoniae Nevada strain with minimal or no toxicity. Cryo-EM characterization of S-F bound to the A. baumannii 70S ribosome defines extensive hydrogen bonding of the S-F steptolidine moiety, as a guanine mimetic, to the 16S rRNA C1054 nucleobase (Escherichia coli numbering) in helix 34, and the carbamoylated gulosamine moiety of S-F with A1196, explaining the high-level resistance conferred by corresponding mutations at the residues identified in single rrn operon E. coli. Structural analysis suggests that S-F probes the A-decoding site, which potentially may account for its miscoding activity. Based on unique and promising activity, we suggest that the streptothricin scaffold deserves further preclinical exploration as a potential therapeutic for drug-resistant, gram-negative pathogens.

Three Reconstructions of 'Effectiveness': Some Implications for State Continuity and Sea-level Rise.

Small Island Developing States (SIDS) are uniquely threatened by rising sea levels. Not only does the retreat of their coastlines place them in danger of losing maritime territory; the concurrent possibility of their landmasses becoming either uninhabitable or completely submerged also threatens their very existence. According to one understanding of the law that governs the continuity and extinction of states, political communities that permanently lose 'effectiveness'-typically understood as sufficient governmental control of a relatively determinate territory with a permanent population-must lose their statehood as well. In this article, I provide three reconstructions of effectiveness, each of which rests upon a different normative rationale. My contention is that, regardless of which reconstruction one adopts, the continuity of submerged SIDS is eminently supportable, notwithstanding the arguments frequently made in favour of their formal extinction.

Placental Mitochondrial Function and Dysfunction in Preeclampsia.

The placenta is a vital organ of pregnancy, regulating adaptation to pregnancy, gestational parent/fetal exchange, and ultimately, fetal development and growth. Not surprisingly, in cases of placental dysfunction-where aspects of placental development or function become compromised-adverse pregnancy outcomes can result. One common placenta-mediated disorder of pregnancy is preeclampsia (PE), a hypertensive disorder of pregnancy with a highly heterogeneous clinical presentation. The wide array of clinical characteristics observed in pregnant individuals and neonates of a PE pregnancy are likely the result of distinct forms of placental pathology underlying the PE diagnosis, explaining why no one common intervention has proven effective in the prevention or treatment of PE. The historical paradigm of placental pathology in PE highlights an important role for utero-placental malperfusion, placental hypoxia and oxidative stress, and a critical role for placental mitochondrial dysfunction in the pathogenesis and progression of the disease. In the current review, the evidence of placental mitochondrial dysfunction in the context of PE will be summarized, highlighting how altered mitochondrial function may be a common feature across distinct PE subtypes. Further, advances in this field of study and therapeutic targeting of mitochondria as a promising intervention for PE will be discussed.

Ad Hominem Criminalisation and the Rule of Law: The Egalitarian Case against Knife Crime Prevention Orders.

This article advances a novel account of ad hominem criminalisation that draws upon a distinct theory of the Rule of Law and its egalitarian foundations. Employing the recent and controversial example of Knife Crime Prevention Orders, as established by the Offensive Weapons Act 2019, it argues that the concept of civic equality is central to understanding the vice of ad hominem criminalisation as an aberrant form of government by law. This vice consists in the manner that such criminalisation individualises, differentiates and instrumentalises the regulatory subject, placing them outwith the bounds of civic equality as established by the Rule of Law.

The SGLT2 inhibitor canagliflozin suppresses lipid synthesis and interleukin-1 beta in ApoE deficient mice.

Sodium-glucose cotransporter 2 inhibitors such as canagliflozin lower blood glucose and reduce cardiovascular events in people with type 2 diabetes through mechanisms that are not fully understood. Canagliflozin has been shown to increase the activity of the AMP-activated protein kinase (AMPK), a metabolic energy sensor important for increasing fatty acid oxidation and energy expenditure and suppressing lipogenesis and inflammation, but whether AMPK activation is important for mediating some of the beneficial metabolic effects of canagliflozin has not been determined. We, therefore, evaluated the effects of canagliflozin in female ApoE-/- and ApoE-/-AMPK ß1-/- mice fed a western diet. Canagliflozin increased fatty acid oxidation and energy expenditure and lowered adiposity, blood glucose and the respiratory exchange ratio independently of AMPK ß1. Canagliflozin also suppressed liver lipid synthesis and the expression of ATP-citrate lyase, acetyl-CoA carboxylase and sterol response element-binding protein 1c independently of AMPK ß1. Canagliflozin lowered circulating IL-1ß and studies in bone marrow-derived macrophages indicated that in contrast with the metabolic adaptations, this effect required AMPK ß1. Canagliflozin had no effect on the size of atherosclerotic plaques in either ApoE-/- and ApoE-/-AMPK ß1-/- mice. Future studies investigating whether reductions in liver lipid synthesis and macrophage IL-1ß are important for the cardioprotective effects of canagliflozin warrant further investigation.

Open Development and Clinical Validation of Multiple 3D-Printed Nasopharyngeal Collection Swabs: Rapid Resolution of a Critical COVID-19 Testing Bottleneck.

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a severe international shortage of the nasopharyngeal swabs that are required for collection of optimal specimens, creating a critical bottleneck blocking clinical laboratories' ability to perform high-sensitivity virological testing for SARS-CoV-2. To address this crisis, we designed and executed an innovative, cooperative, rapid-response translational-research program that brought together health care workers, manufacturers, and scientists to emergently develop and clinically validate new swabs for immediate mass production by 3D printing. We performed a multistep preclinical evaluation of 160 swab designs and 48 materials from 24 companies, laboratories, and individuals, and we shared results and other feedback via a public data repository (http://github.com/rarnaout/Covidswab/). We validated four prototypes through an institutional review board (IRB)-approved clinical trial that involved 276 outpatient volunteers who presented to our hospital's drive-through testing center with symptoms suspicious for COVID-19. Each participant was swabbed with a reference swab (the control) and a prototype, and SARS-CoV-2 reverse transcriptase PCR (RT-PCR) results were compared. All prototypes displayed excellent concordance with the control (κ = 0.85 to 0.89). Cycle threshold (CT ) values were not significantly different between each prototype and the control, supporting the new swabs' noninferiority (Mann-Whitney U [MWU] test, P > 0.05). Study staff preferred one of the prototypes over the others and preferred the control swab overall. The total time elapsed between identification of the problem and validation of the first prototype was 22 days. Contact information for ordering can be found at http://printedswabs.org Our experience holds lessons for the rapid development, validation, and deployment of new technology for this pandemic and beyond.

[Racism and the practice of medicine†: elements for a required learning]. / Racisme et pratique de la médecine†: éléments pour un apprentissage nécessaire.

The new catalogue of objectives for medical education at Swiss universities (PROFILES) underlines the importance of teaching the impact of ethnic, cultural, spiritual and religious differences and the socio-economic determinants of health and illness on health and care. At the same time, the social reality of the moment reminds us that racism is still present in our societies. Therefore, education for medical students is necessary. This should include basic knowledge but also, and above all, an understanding of the underlying mechanisms that will enable them to grasp the notions of prejudice, stereotypes and discrimination. Finally, introspection, the acquisition of cross-cultural skills and cultural humility will help to deal with this other epidemic.

Le nouveau catalogue des objectifs d'enseignement de la médecine dans les universités suisses (PROFILES) souligne l'importance de l'enseignement de l'impact sur la santé et les soins des différences ethniques, culturelles, spirituelles, religieuses, et des déterminants socio-économiques de la santé et de la maladie. Parallèlement, la réalité sociale du moment nous rappelle que le racisme est toujours présent dans nos sociétés. Dès lors, un enseignement aux étudiant·e·s de médecine est nécessaire. Celui-ci devra intégrer des connaissances de base mais aussi et surtout la compréhension des mécanismes sous-jacents qui permettra d'appréhender les notions de préjugés, stéréotypes et discriminations. Enfin, l'introspection, l'acquisition de compétences transculturelles et d'humilité culturelle permettront de faire face à cette autre épidémie.

Following in the footsteps of tobacco and alcohol? Stakeholder discourse in UK newspaper coverage of the Soft Drinks Industry Levy.

OBJECTIVE: In politically contested health debates, stakeholders on both sides present arguments and evidence to influence public opinion and the political agenda. The present study aimed to examine whether stakeholders in the Soft Drinks Industry Levy (SDIL) debate sought to establish or undermine the acceptability of this policy through the news media and how this compared with similar policy debates in relation to tobacco and alcohol industries. DESIGN: Quantitative and qualitative content analysis of newspaper articles discussing sugar-sweetened beverage (SSB) taxation published in eleven UK newspapers between 1 April 2015 and 30 November 2016, identified through the Nexis database. Direct stakeholder citations were entered in NVivo to allow inductive thematic analysis and comparison with an established typology of industry stakeholder arguments used by the alcohol and tobacco industries. SETTING: UK newspapers. PARTICIPANTS: Proponents and opponents of SSB tax/SDIL cited in UK newspapers. RESULTS: Four hundred and ninety-one newspaper articles cited stakeholders' (n 287) arguments in relation to SSB taxation (n 1761: 65 % supportive and 35 % opposing). Stakeholders' positions broadly reflected their vested interests. Inconsistencies arose from: changes in ideological position; insufficient clarity on the nature of the problem to be solved; policy priorities; and consistency with academic rigour. Both opposing and supportive themes were comparable with the alcohol and tobacco industry typology. CONCLUSIONS: Public health advocates were particularly prominent in the UK newspaper debate surrounding the SDIL. Advocates in future policy debates might benefit from seeking a similar level of prominence and avoiding inconsistencies by being clearer about the policy objective and mechanisms.

The Neuromodulation Appropriateness Consensus Committee on Best Practices for Dorsal Root Ganglion Stimulation.

INTRODUCTION: The Neuromodulation Appropriateness Consensus Committee (NACC) is dedicated to improving the safety and efficacy of neuromodulation and thus improving the lives of patients undergoing neuromodulation therapies. With continued innovations in neuromodulation comes the need for evolving reviews of best practices. Dorsal root ganglion (DRG) stimulation has significantly improved the treatment of complex regional pain syndrome (CRPS), among other conditions. Through funding and organizational leadership by the International Neuromodulation Society (INS), the NACC reconvened to develop the best practices consensus document for the selection, implantation and use of DRG stimulation for the treatment of chronic pain syndromes. METHODS: The NACC performed a comprehensive literature search of articles about DRG published from 1995 through June, 2017. A total of 2538 article abstracts were then reviewed, and selected articles graded for strength of evidence based on scoring criteria established by the US Preventive Services Task Force. Graded evidence was considered along with clinical experience to create the best practices consensus and recommendations. RESULTS: The NACC achieved consensus based on peer-reviewed literature and experience to create consensus points to improve patient selection, guide surgical methods, improve post-operative care, and make recommendations for management of patients treated with DRG stimulation. CONCLUSION: The NACC recommendations are intended to improve patient care in the use of this evolving therapy for chronic pain. Clinicians who choose to follow these recommendations may improve outcomes.

Novel Pharmacological Probes Reveal ABHD5 as a Locus of Lipolysis Control in White and Brown Adipocytes.

Current knowledge regarding acute regulation of adipocyte lipolysis is largely based on receptor-mediated activation or inhibition of pathways that influence intracellular levels of cAMP, thereby affecting protein kinase A (PKA) activity. We recently identified synthetic ligands of α-ß-hydrolase domain containing 5 (ABHD5) that directly activate adipose triglyceride lipase (ATGL) by dissociating ABHD5 from its inhibitory regulator, perilipin-1 (PLIN1). In the current study, we used these novel ligands to determine the direct contribution of ABHD5 to various aspects of lipolysis control in white (3T3-L1) and brown adipocytes. ABHD5 ligands stimulated adipocyte lipolysis without affecting PKA-dependent phosphorylation on consensus sites of PLIN1 or hormone-sensitive lipase (HSL). Cotreatment of adipocytes with synthetic ABHD5 ligands did not alter the potency or maximal lipolysis efficacy of the ß-adrenergic receptor (ADRB) agonist isoproterenol (ISO), indicating that both target a common pool of ABHD5. Reducing ADRB/PKA signaling with insulin or desensitizing ADRB suppressed lipolysis responses to a subsequent challenge with ISO, but not to ABHD5 ligands. Lastly, despite strong treatment differences in PKA-dependent phosphorylation of HSL, we found that ligand-mediated activation of ABHD5 led to complete triglyceride hydrolysis, which predominantly involved ATGL, but also HSL. These results indicate that the overall pattern of lipolysis controlled by ABHD5 ligands is similar to that of isoproterenol, and that ABHD5 plays a central role in the regulation of adipocyte lipolysis. As lipolysis is critical for adaptive thermogenesis and in catabolic tissue remodeling, ABHD5 ligands may provide a means of activating these processes under conditions where receptor signaling is compromised.

Clinical aspects of hyperthyroidism, hypothyroidism, and thyroid screening in pregnancy.

OBJECTIVE: To evaluate the peer-reviewed literature on hypothyroidism, hyperthyroidism, and thyroid autoimmunity in pregnancy. METHODS: We review published studies on thyroid autoimmunity and dysfunction in pregnancy, the impact of thyroid disease on pregnancy, and discuss implications for screening. RESULTS: Overt hyperthyroidism and hypothyroidism are responsible for adverse obstetric and neonatal events. Several studies of association suggest that either subclinical hypothyroidism or thyroid autoimmunity increase the risk of complications. One randomized controlled trial showed that pregnant women with subclinical hypothyroidism benefit from treatment in terms of obstetric and neonatal complications, whereas another study demonstrated no benefit in the intelligence quotient of babies born to women with subclinical hypothyroidism. Thyroid autoimmunity has been associated with increased rate of pregnancy loss, recurrent miscarriage, and preterm delivery. CONCLUSION: Current guidelines agree that overt hyperthyroidism and hypothyroidism need to be promptly treated and that as potential benefits outweigh potential harm, subclinical hypothyroidism also requires substitutive treatment. The chance that women with thyroid autoimmunity may benefit from levothyroxine treatment to improve obstetric outcome is intriguing, but adequately powered randomized controlled trials are needed. The issue of universal thyroid screening at the beginning of pregnancy is still a matter of debate, and aggressive case-finding is supported.

Maternal subclinical hypothyroidsm and gestational diabetes mellitus: a meta-analysis.

OBJECTIVE: The association between subclinical hypothyroidism (SCH) and gestational diabetes mellitus (GDM) is controversial. This review evaluates whether the risk of GDM is different in pregnant women with SCH compared to euthyroid pregnant women. METHODS: A computerized search of the MEDLINE and EMBASE databases was conducted from their inceptions to July 2013 and was complemented with the perusal of the reference sections of the retrieved articles. Prespecified criteria were applied to assess eligibility, and standard meta-analytic methodology was employed for evidence synthesis. RESULTS: Six cohort studies, reporting data on 35,350 pregnant women (1,216 women with SCH), were identified. The risk of GDM in pregnant women with SCH was found to be substantially higher compared to euthyroid pregnant women (5 studies, pooled unadjusted odds ratio [OR]: 1.35, 95% confidence interval [CI]: 1.05-1.75, I2: 41%, Harbord test P = .44). Similarly, the risk of GDM was estimated to be significantly higher in pregnant women with SCH when using adjusted estimates (3 studies, pooled adjusted OR: 1.39, 95% CI: 1.07-1.79, I2: 0%). Neither finding remained significant in sensitivity analyses. CONCLUSION: A modestly increased risk of GDM might be present in pregnant women with SCH compared to euthyroid pregnant women. Assuming a 5% baseline risk of GDM and that SCH increases the risk of GDM by 50% (in odds) compared to a euthyroid population, then there would be 1 extra case of GDM in every 43 pregnant women with SCH. This preliminary finding warrants further investigation.

Competency in electrocardiogram interpretation among graduating medical students.

BACKGROUND: The ability to accurately interpret electrocardiogram (ECG) abnormalities is a core competency for graduating medical students (GMS). Incorrect interpretation of ECG findings can result in adverse patient outcomes. To our knowledge, there has been no published study evaluating the level of competency in ECG interpretation in GMS. PURPOSES: To evaluate the ability of graduating medical students to interpret abnormal and critical ECGs and to correlate student performance with self-reported confidence and adequacy of ECG training. METHODS: A list of 22 ECGs which GMS are expected to identify was developed. Classic examples of each ECG were identified and verified by two board-certified cardiologists. The 22 ECGs along with 11 questions related to confidence and degree of ECG training were administered to (a) 168 4th-year George Washington University School of Medicine (GWUSOM) students, (b) 63 incoming housestaff to GWUSOM, and (c) 22 graduating internal medicine housestaff. RESULTS: Given the lack of statistical differences, GW medical students and incoming housestaff were combined into a single group (GMS, n=231). Mean number of correct answers on the 22 ECG examination for GMS was 8.2 (SE=0.529) and 13.9 (SE=1.312) for graduating residents (p<.0001). On the 6 life-threatening ECGs, GMS scored lower than graduating residents (3.4 SE=0.191 vs. 4.6 SE=0.541; p<.0002). Mean score in the GMS group was associated with increasing levels of reported confidence and degree of ECG experience. CONCLUSIONS: A 22-item ECG examination was developed, piloted, and demonstrated to have construct validity. GMS had a limited level of competency in ECG interpretation which was correlated with reported self-confidence and degree of ECG exposure in Years 3-4.

High burden of viruses and bacterial pathobionts drives heightened nasal innate immunity in children.

Studies during the COVID-19 pandemic showed that children had heightened nasal innate immune responses compared with adults. To evaluate the role of nasal viruses and bacteria in driving these responses, we performed cytokine profiling and comprehensive, symptom-agnostic testing for respiratory viruses and bacterial pathobionts in nasopharyngeal samples from children tested for SARS-CoV-2 in 2021-22 (n = 467). Respiratory viruses and/or pathobionts were highly prevalent (82% of symptomatic and 30% asymptomatic children; 90 and 49% for children <5 years). Virus detection and load correlated with the nasal interferon response biomarker CXCL10, and the previously reported discrepancy between SARS-CoV-2 viral load and nasal interferon response was explained by viral coinfections. Bacterial pathobionts correlated with a distinct proinflammatory response with elevated IL-1ß and TNF but not CXCL10. Furthermore, paired samples from healthy 1-year-olds collected 1-2 wk apart revealed frequent respiratory virus acquisition or clearance, with mucosal immunophenotype changing in parallel. These findings reveal that frequent, dynamic host-pathogen interactions drive nasal innate immune activation in children.

Wireless motility capsule test in children with upper gastrointestinal symptoms.

OBJECTIVE: To compare scintigraphic gastric emptying and antroduodenal manometry (ADM) studies with the wireless motility capsule test in symptomatic pediatric patients. STUDY DESIGN: Patients aged 8-17 years with severe upper gastrointestinal symptoms (ie, nausea, vomiting, retching, abdominal pain) referred for ADM were recruited. A standardized protocol for ADM was used. On a different day, participants were given a standardized meal and then swallowed the wireless motility capsule. A wireless receiver unit worn during the study recorded transmitted data. If not performed previously, a 2-hour scintigraphic gastric emptying study was completed at the time of ADM testing. RESULTS: A total of 22 patients were recruited, of whom 21 had complete scintigraphic gastric emptying study data and 20 had complete ADM data. The wireless motility capsule test had 100% sensitivity and 50% specificity in detecting gastroparesis compared with the 2-hour scintigraphic gastric emptying study. The wireless motility capsule test detected motor abnormalities in 17 patients, compared with 10 detected by ADM. Dichotomous comparison yielded a diagnostic difference between ADM and the wireless motility capsule test (P<.01). Migrating motor complexes were recognized in all patients by both ADM and the wireless motility capsule test. The wireless motility capsule test was well tolerated in all patients, and there were no side effects. CONCLUSION: In symptomatic pediatric patients, the wireless motility capsule test is highly sensitive compared with scintigraphic gastric emptying studies in detecting gastroparesis, and seems to be more sensitive than ADM in detecting motor abnormalities.

The effects of recreational sport on VO2peak, VO2 kinetics and submaximal exercise performance in males and females.

The purpose of the present study was to examine changes in VO(2peak), VO(2) kinetics and steady-state exercise performance following 4 weeks of participation in recreational sport. Subjects (male n = 8, female n = 9) participated in recreational sport (basketball, floor hockey and soccer) four times per week for 4 weeks. Both before and after training, VO(2peak) was measured on a cycle ergometer, VO(2) kinetics was determined as the average of three transitions to 80 W, and heart rate (HR) and respiratory exchange ratio (RER) were measured during 60 min at a work rate corresponding to 50 % of pre-training VO(2peak). HR was also monitored during all training sessions. After training, VO(2peak) was increased in females, but not males, while VO(2) kinetics (τVO(2)) were sped in both males and females. HR during constant load exercise was reduced in both males and females, but exercise RER was only reduced in females. Mean HR during participation in sport was higher in males than females and higher during basketball than both floor hockey and soccer. These results demonstrate that training adaptations traditionally associated with endurance exercise can also be obtained through regular participation in recreational sport.

A comparison of rat models that best mimic immune-driven preeclampsia in humans.

Preeclampsia (PE), a hypertensive pregnancy disorder, can originate from varied etiology. Placenta malperfusion has long been considered the primary cause of PE. However, we and others have showed that this disorder can also result from heightened inflammation at the maternal-fetal interface. To advance our understanding of this understudied PE subtype, it is important to establish validated rodent models to study the pathophysiology and test therapies. We evaluated three previously described approaches to induce inflammation-mediated PE-like features in pregnant rats: 1) Tumor necrosis factor-α (TNF-α) infusion via osmotic pump from gestational day (GD) 14-19 at 50ng/day/animal; 2) Polyinosinic:polycytidylic acid (Poly I:C) intraperitoneal (IP) injections from GD 10-18 (alternate days) at 10mg/kg/day/animal; and, 3) Lipopolysaccharide (LPS) IP injections from GD 13-18 at 20ug-70ug/kg/day per animal. Maternal blood pressure was measured by tail-cuff. Upon sacrifice, fetal and placenta weights were recorded. Placenta histomorphology was assessed using H&E sections. Placenta inflammation was determined by quantifying TNF-α levels and inflammatory gene expression. Placenta metabolic and mitochondrial health were determined by measuring mitochondrial respiration rates and placenta NAD+/NADH content. Of the three rodent models tested, we found that Poly I:C and LPS decreased both fetal weight and survival; and correlated with a reduction in region specific placenta growth. As the least effective model characterized, TNF-α treatment resulted in a subtle decrease in fetal/placenta weight and placenta mitochondrial respiration. Only the LPS model was able to induce maternal hypertension and exhibited pronounced placenta metabolic and mitochondrial dysfunction, common features of PE. Thus, the rat LPS model was most effective for recapitulating features observed in cases of human inflammatory PE. Future mechanistic and/or therapeutic intervention studies focuses on this distinct PE patient population may benefit from the employment of this rodent model of PE.

RND Pump-Mediated Efflux of Amotosalen, a Compound Used in Pathogen Inactivation Technology to Enhance Safety of Blood Transfusion Products, May Compromise Its Gram-Negative Anti-Bacterial Activity.

Pathogen inactivation is a strategy to improve the safety of transfusion products. The only pathogen reduction technology for blood products currently approved in the US utilizes a psoralen compound, called amotosalen, in combination with UVA light to inactivate bacteria, viruses, and protozoa. Psoralens have structural similarity to bacterial multidrug efflux pump substrates. As these efflux pumps are often overexpressed in multidrug-resistant pathogens, we tested whether contemporary drug-resistant pathogens might show resistance to amotosalen and other psoralens based on multidrug efflux mechanisms through genetic, biophysical, and molecular modeling analysis. The main efflux systems in Enterobacterales, Acinetobacter baumannii, and Pseudomonas aeruginosa are tripartite resistance-nodulation-cell division (RND) systems, which span the inner and outer membranes of Gram-negative pathogens, and expel antibiotics from the bacterial cytoplasm into the extracellular space. We provide evidence that amotosalen is an efflux substrate for the E. coli AcrAB, Acinetobacter baumannii AdeABC, and P. aeruginosa MexXY RND efflux pumps. Furthermore, we show that the MICs for contemporary Gram-negative bacterial isolates for these species and others in vitro approached and exceeded the concentration of amotosalen used in the approved platelet and plasma inactivation procedures. These findings suggest that otherwise safe and effective inactivation methods should be further studied to identify possible gaps in their ability to inactivate contemporary, multidrug-resistant bacterial pathogens. IMPORTANCE Pathogen inactivation is a strategy to enhance the safety of transfused blood products. We identify the compound, amotosalen, widely used for pathogen inactivation, as a bacterial multidrug efflux substrate. Specifically, experiments suggest that amotosalen is pumped out of bacteria by major efflux pumps in E. coli, Acinetobacter baumannii, and Pseudomonas aeruginosa. Such efflux pumps are often overexpressed in multidrug-resistant pathogens. Importantly, the MICs for contemporary multidrug-resistant Enterobacterales, Acinetobacter baumannii, Pseudomonas aeruginosa, Burkholderia spp., and Stenotrophomonas maltophilia isolates approached or exceeded the amotosalen concentration used in approved platelet and plasma inactivation procedures, potentially as a result of efflux pump activity. Although there are important differences in methodology between our experiments and blood product pathogen inactivation, these findings suggest that otherwise safe and effective inactivation methods should be further studied to identify possible gaps in their ability to inactivate contemporary, multidrug-resistant bacterial pathogens.

The pathophysiology of brain swelling associated with subdural hemorrhage: the role of the trigeminovascular system.

INTRODUCTION: This paper reviews the evidence in support of the hypothesis that the trigeminal system mediates brain swelling associated with subdural bleeding. The trigeminovascular system has been extensively studied in migraine; it may play an important but under-recognized role in the response to head trauma. Nerve fibers originating in trigeminal ganglion cells are the primary sensors of head trauma and, through their collateral innervation of the intracranial and dural blood vessels, are capable of inciting a cascade of vascular responses and brain swelling. The extensive trigeminal representation in the brainstem initiates and augments autonomic responses. Blood and tissue injury in the dura incite neurogenic inflammatory responses capable of sensitizing dural nerves and potentiating the response to trauma. DISCUSSION: The trigeminal system may provide the anatomo-physiological link between small-volume, thin subdural bleeds and swelling of the underlying brain. This physiology may help to explain the poorly understood phenomena of "second-impact syndrome," the infant response to subdural bleeding (the "big black brain"), as well as post-traumatic subdural effusions. Considerable age-specific differences in the density of dural innervation exist; age-specific responses of this innervation may explain differences in the brain's response to trauma in the young. An understanding of this pathophysiology is crucial to the development of intervention and treatment of these conditions. Antagonists to specific neuropeptides of the trigeminal system modify brain swelling after trauma and should be further explored as potential therapy in brain trauma and subdural bleeding.