mRNA lipid nanoparticles expressing cell-surface cleavage independent HIV Env trimers elicit autologous tier-2 neutralizing antibodies.

The HIV-1 envelope glycoprotein (Env) is the sole neutralizing determinant on the surface of the virus. The Env gp120 and gp41 subunits mediate receptor binding and membrane fusion and are generated from the gp160 precursor by cellular furins. This cleavage event is required for viral entry. One approach to generate HIV-1 neutralizing antibodies following immunization is to express membrane-bound Env anchored on the cell-surface by genetic means using the natural HIV gp41 transmembrane (TM) spanning domain. To simplify the process of Env trimer membrane expression we sought to remove the need for Env precursor cleavage while maintaining native-like conformation following genetic expression. To accomplish these objectives, we selected our previously developed 'native flexibly linked' (NFL) stabilized soluble trimers that are both near-native in conformation and cleavage-independent. We genetically fused the NFL construct to the HIV TM domain by using a short linker or by restoring the native membrane external proximal region, absent in soluble trimers, to express the full HIV Env ectodomain on the plasma membrane. Both forms of cell-surface NFL trimers, without and with the MPER, displayed favorable antigenic profiles by flow cytometry when expressed from plasmid DNA or mRNA. These results were consistent with the presence of well-ordered cell surface native-like trimeric Env, a necessary requirement to generate neutralizing antibodies by vaccination. Inoculation of rabbits with mRNA lipid nanoparticles (LNP) expressing membrane-bound stabilized HIV Env NFL trimers generated tier 2 neutralizing antibody serum titers in immunized animals. Multiple inoculations of mRNA LNPs generated similar neutralizing antibody titers compared to immunizations of matched NFL soluble proteins in adjuvant. Given the recent success of mRNA vaccines to prevent severe COVID, these are important developments for genetic expression of native-like HIV Env trimers in animals and potentially in humans.

Paths of least resistance: Unconventional effector secretion by fungal and oomycete plant pathogens.

Effector secretion by different routes mediates the molecular interplay between host plant and pathogen, but mechanistic details in eukaryotes are sparse. This may limit the discovery of new effectors that could be utilized for improving host plant disease resistance. In fungi and oomycetes, apoplastic effectors are secreted via the conventional ER-Golgi pathway while cytoplasmic effectors are packaged into vesicles that bypass Golgi in an unconventional protein secretion (UPS) pathway. In Magnaporthe oryzae, the Golgi bypass UPS pathway incorporates components of the exocyst complex and a t-SNARE, presumably to fuse Golgi bypass vesicles to the fungal plasma membrane. Upstream, cytoplasmic effector mRNA translation in M. oryzae requires the efficient decoding of AA-ending codons. This involves the modification of wobble uridines in the anticodon loop of cognate tRNAs and fine-tunes cytoplasmic effector translation and secretion rates to maintain biotrophic interfacial complex integrity and permit host infection. Thus, plant-fungal interface integrity is intimately tied to effector codon usage, a surprising constraint on pathogenicity. Here, we discuss these findings within the context of fungal and oomycete effector discovery, delivery, and function in host cells. We show how cracking the codon code for unconventional cytoplasmic effector secretion in M. oryzae has revealed AA-ending codon usage bias in cytoplasmic effector mRNAs across kingdoms, including within the RxLR-dEER motif-encoding sequence of a bona fide Phytophthora infestans cytoplasmic effector, suggesting its subjection to translational speed control. By focusing on recent developments in understanding unconventional effector secretion, we draw attention to this important but understudied area of host-pathogen interactions.

Germline susceptibility from broad genomic profiling of pediatric brain cancers.

Background: Identifying germline predisposition in CNS malignancies is of increasing clinical importance, as it contributes to diagnosis and prognosis, and determines aspects of treatment. The inclusion of germline testing has historically been limited due to challenges surrounding access to genetic counseling, complexity in acquiring a germline comparator specimen, concerns about the impact of findings, or cost considerations. These limitations were further defined by the breadth and scope of clinical testing to precisely identify complex variants as well as concerns regarding the clinical interpretation of variants including those of uncertain significance. Methods: In the course of conducting an IRB-approved protocol that performed genomic, transcriptomic and methylation-based characterization of pediatric CNS malignancies, we cataloged germline predisposition to cancer based on paired exome capture sequencing, coupled with computational analyses to identify variants in known cancer predisposition genes and interpret them relative to established clinical guidelines. Results: In certain cases, these findings refined diagnosis or prognosis or provided important information for treatment planning. Conclusions: We outline our aggregate findings on cancer predisposition within this cohort which identified 16% of individuals (27 of 168) harboring a variant predicting cancer susceptibility and contextualize the impact of these results in terms of treatment-related aspects of precision oncology.

Towards pharmacokinetic boosting of phenoxymethylpenicillin (penicillin-V) using probenecid for the treatment of bacterial infections.

In the face of increasing antimicrobial tolerance and resistance there is a global obligation to optimise oral antimicrobial dosing strategies including narrow spectrum penicillins, such as penicillin-V. We conducted a randomised, crossover study in healthy volunteers to characterise the influence of probenecid on penicillin-V pharmacokinetics and estimate the pharmacodynamics against Streptococcus pneumoniae. Twenty participants took six doses of penicillin-V (250 mg, 500 mg or 750 mg four times daily) with and without probenecid. Total and free concentrations of penicillin-V and probenecid were measured at two timepoints. A pharmacokinetic model was developed, and the probability of target attainment (PTA) calculated. The mean difference (95% CI) between penicillin-V alone and in combination with probenecid for serum total and free penicillin-V concentrations was significantly different at both timepoints (total: 45 min 4.32 (3.20-5.32) mg/L p < 0.001, 180 min 2.2 (1.58-3.25) mg/L p < 0.001; free: 45 min 1.15 (0.88-1.42) mg/L p < 0.001, 180 min 0.5 (0.35-0.76) mg/L p < 0.001). There was no difference between the timepoints in probenecid concentrations. PTA analysis shows probenecid allows a fourfold increase in MIC cover. Addition of probenecid was safe and well tolerated. The data support further research into improved dosing structures for complex outpatient therapy and might also be used to address penicillin supply shortages.

First-In-Human Demonstration of High Frequency Electrical Motor Nerve Block: Case Report.

ABSTRACT: This feasibility study tested the capability of high frequency stimulation (HFS) to block muscle contractions elicited by electrical stimulation of the same nerve proximally. During a tendon lengthening surgery in the forearm, the anterior interosseous nerve (AIN) was exposed. A specialized nerve cuff electrode was placed around the nerve, and a stimulating probe held on the nerve 1 cm proximal to the cuff electrode delivered pulses of current causing the pronator quadratus muscle to contract. Through the cuff electrode, 20 kHz HFS was delivered to the nerve for 10 seconds during proximal stimulation. HFS amplitudes between 5 and 10 mA peak-to-peak were tested to determine which produced complete and partial block of the electrically induced contractions. The minimum HFS amplitude that produced complete block was 8 mA, with lower amplitudes producing partial block. In all trials, muscle contractions resumed immediately after HFS was turned off. This demonstration of high frequency electrical nerve block is a milestone in the road to clinical implementation of HFS mediated motor block for spasticity.

Preparation of Neptunyl and Plutonyl Acetates To Access Nonaqueous Transuranium Coordination Chemistry.

Uranyl diacetate dihydrate is a useful reagent for the preparation of uranyl (UO22+) coordination complexes, as it is a well-defined stoichiometric compound featuring moderately basic acetates that can facilitate protonolysis reactivity, unlike other anions commonly used in synthetic actinide chemistry such as halides or nitrate. Despite these attractive features, analogous neptunium (Np) and plutonium (Pu) compounds are unknown to date. Here, a modular synthetic route is reported for accessing stoichiometric neptunyl(VI) and plutonyl(VI) diacetate compounds that can serve as starting materials for transuranic coordination chemistry. The new NpO22+ and PuO22+ complexes, as well as a corresponding molecular UO22+ complex, are isomorphous in the solid state, and in solution show similar solubility properties that facilitate their use in synthesis. In both solid and solution state, the +VI oxidation state (O.S.) is maintained, as demonstrated by vibrational and optical spectroscopy, confirming that acetate anions stabilize the oxidizing, high-valent +VI states of Np and Pu as they do for the more stable U(VI). All three acetate salts readily react with a model diprotic ligand, affording incorporation of U(VI), Np(VI), and Pu(VI) cores into molecular coordination compounds that occurs concomitantly with elimination of acetic acid; the new complexes are high-valent, yet overall charge neutral, facilitating entry into nonaqueous chemistry by rational synthesis. Computational studies reveal that the dianionic ligand framework assists in stabilizing the +VI O.S. via donation to the 5f shells of the actinides, highlighting the potential usefulness of protonolysis reactivity toward preparation of stabilized high-valent transuranic species.

A review of prospective studies regarding percutaneous peripheral nerve stimulation treatment in the management of chronic pain.

Conventionally, peripheral nerve stimulation (PNS) for treatment of chronic pain has involved a two-stage process: a short-term (e.g., 7 days) trial and, if significant pain relief is achieved, a permanent PNS system is implanted. A percutaneous PNS treatment is now available where a coiled lead may be implanted for up to 60 days with the goal of producing sustained relief. In the present review, published prospective trials using percutaneous PNS treatment were identified and synthesized. The collected evidence indicates that percutaneous PNS treatment for up to 60 days provides durable clinically significant improvements in pain and pain interference. Similar efficacy across diverse targets and etiologies supports the broad applicability for use within the chronic pain population using this nonopioid technology.

What is this review about? This review looks at a drug-free way to treat chronic pain called percutaneous peripheral nerve stimulation (PNS). Percutaneous means it is placed through the skin. PNS applies small amounts of electricity to the nerves to reduce chronic pain. Most PNS systems involve a two-step process. A short trial is first performed to see if a patient has pain relief. A permanent system is then placed if the person had pain relief. Percutaneous PNS treatments are different. They use a thin wire called a lead placed in the body for up to 60 days. The lead is taken out at the end of the treatment period. Studies have shown that this type of PNS treatment can reduce chronic pain even after the treatment is over. No previous article has collected all these studies of percutaneous PNS in one place.What evidence was gathered? This review found evidence from studies on treatment of chronic pain. Pain types included shoulder pain, neuropathic pain and low back pain. It found that percutaneous PNS treatment for up to 60 days can reduce pain and how pain interferes with daily life.How can these data lead to better care for patients? These findings mean that percutaneous PNS treatments could be a useful, non-drug option for many types of chronic pain.

Transcriptomics is essential but not sufficient to unravel complex plant-pathogen interactions.

KEY MESSAGE: A group of genes that were upregulated in a resistant cultivar while downregulated in a susceptible cultivar in a transcriptomics analysis of potato challenged by Spongospora subterranea infection, did not show the same expression pattern at the protein level.

Telemedicine impact on patient disparities and physician practice patterns in cancer rehabilitation: A multicenter retrospective study.

OBJECTIVE: To examine the impact of telemedicine on demographic and practice patterns between outpatients receiving virtual versus in-person cancer rehabilitation physiatry care. DESIGN: Multicenter retrospective study. SETTING: Outpatient cancer rehabilitation physiatry clinics at four academic medical centers in the United States. PATIENTS: Patients with cancer diagnoses or history of cancer diagnosis. INTERVENTIONS: Cancer rehabilitation physiatry encounters. MAIN OUTCOME MEASURES: Visit mode (in-person, telemedicine); disparities variables (age, race, and gender) by visit mode, and practice interventions (imaging, medications, procedures, other orders, and orders of any type) by visit mode. RESULTS: Among a total of 7004 encounters, 2687 unique patients were found. In-person participants were significantly older than the average telemedicine participant (mean 62.9 vs. 60.7 years; p < .001). A race effect was seen (p = .037) with individuals reporting as Asian or other being more likely to have telemedicine encounters. No gender disparities were seen. Using a random visit analysis model to compare populations receiving in-person versus telemedicine care, a slight majority (53%) of follow-up visits were via telemedicine, versus 40% of new patient visits (p < .001). No significant differences were seen in medication prescribing frequency (38.9% telemedicine vs. 36.7% in-person, adjusted relative risk [RR]: 0.988, confidence interval [CI]: 0.73-1.34; p = .988) or imaging frequency (2.4% telemedicine vs. 7.6%; adjusted RR: 0.784, CI: 0.44-1.39; p = .408) between telemedicine versus in-person visit types. Other orders were significantly less likely to be placed during telemedicine than in-person visits (19.9% telemedicine vs. 28.6% in-person; adjusted RR: 0.623, CI: 0.45-0.86, p = .004). Order(s) of any type were placed in 54% of visits (52% telemedicine vs. 56% in-person; adjusted RR: 0.92 for telemedicine, CI: 0.83-1.01, p = .082). CONCLUSIONS: Telemedicine has been integrated into cancer rehabilitation physiatry practices and appears to be conducive for placing many types of orders, especially medications. Age was found to be the only major demographic difference between in-person and telehealth patients.

Intrathecal Dexamethasone and Dexmedetomidine as Adjuncts to Bupivacaine in Elective Cesarean Section: A Case Series.

The purpose of this study was to investigate whether the combination of intrathecal dexamethasone and dexmedetomidine in combination with bupivacaine in spinal anesthesia is effective for reducing nausea, vomiting, shivering, and pain. A retrospective review of records was used to examine the outcomes of patients undergoing cesarean delivery under spinal anesthesia with dexamethasone, dexmedetomidine, and bupivacaine. The records of 11 consecutive patients who underwent cesarean delivery under spinal anesthesia with intrathecal dexamethasone and dexmedetomidine in combination with bupivacaine were evaluated. Data collected included patient demographics, medications and fluids administered, presence of nausea, vomiting, shivering, intraoperative breakthrough pain, and postoperative pain. There were no reported complications related to the administration of intrathecal dexamethasone and dexmedetomidine in combination with bupivacaine in this case series of patients. No patients required treatment for intraoperative vomiting, shivering, or breakthrough pain. One patient required opioid pain medication postoperatively. This case series demonstrates that the administration of intrathecal dexamethasone and dexmedetomidine in combination with bupivacaine for patients undergoing elective cesarean section appears to be safe and offers some advantages as to traditional methods of intrathecal delivery for this surgical procedure.

Defining the phylogenetics and resistome of the major Clostridioides difficile ribotypes circulating in Australia.

Clostridioides difficile infection (CDI) remains a significant public health threat globally. New interventions to treat CDI rely on an understanding of the evolution and epidemiology of circulating strains. Here we provide longitudinal genomic data on strain diversity, transmission dynamics and antimicrobial resistance (AMR) of C. difficile ribotypes (RTs) 014/020 (n=169), 002 (n=77) and 056 (n=36), the three most prominent C. difficile strains causing CDI in Australia. Genome scrutiny showed that AMR was uncommon in these lineages, with resistance-conferring alleles present in only 15/169 RT014/020 strains (8.9 %), 1/36 RT056 strains (2.78 %) and none of 77 RT002 strains. Notably, ~90 % of strains were resistant to MLSB agents in vitro, but only ~5.9 % harboured known resistance alleles, highlighting an incongruence between AMR genotype and phenotype. Core genome analyses revealed all three RTs contained genetically heterogeneous strain populations with limited evidence of clonal transmission between CDI cases. The average number of pairwise core genome SNP (cgSNP) differences within each RT group ranged from 23.3 (RT056, ST34, n=36) to 115.6 (RT002, ST8, n=77) and 315.9 (RT014/020, STs 2, 13, 14, 49, n=169). Just 19 clonal groups (encompassing 40 isolates), defined as isolates differing by ≤2 cgSNPs, were identified across all three RTs (RT014/020, n=14; RT002, n=3; RT056, n=2). Of these clonal groups, 63 % (12/19) comprised isolates from the same Australian State and 37 % (7/19) comprised isolates from different States. The low number of plausible transmission events found for these major RTs (and previously documented populations in animal and environmental sources/reservoirs) points to widespread and persistent community sources of diverse C. difficile strains as opposed to ongoing nationwide healthcare outbreaks dominated by a single clone. Together, these data provide new insights into the evolution of major lineages causing CDI in Australia and highlight the urgent need for enhanced surveillance, and for public health interventions to move beyond the healthcare setting and into a One Health paradigm to effectively combat this complex pathogen.

First evidence for human occupation of a lava tube in Arabia: The archaeology of Umm Jirsan Cave and its surroundings, northern Saudi Arabia.

Recent advances in interdisciplinary archaeological research in Arabia have focused on the evolution and historical development of regional human populations as well as the diverse patterns of cultural change, migration, and adaptations to environmental fluctuations. Obtaining a comprehensive understanding of cultural developments such as the emergence and lifeways of Neolithic groups has been hindered by the limited preservation of stratified archaeological assemblages and organic remains, a common challenge in arid environments. Underground settings like caves and lava tubes, which are prevalent in Arabia but which have seen limited scientific exploration, offer promising opportunities for addressing these issues. Here, we report on an archaeological excavation and a related survey at and around Umm Jirsan lava tube in the Harrat Khaybar, north-western Saudi Arabia. Our results reveal repeated phases of human occupation of the site ranging from at least the Neolithic through to the Chalcolithic/Bronze Age. Pastoralist use of the lava tube and surrounding landscape is attested in rock art and faunal records, suggesting that Umm Jirsan was situated along a pastoral route linking key oases. Isotopic data indicates that herbivores primarily grazed on wild grasses and shrubs rather than being provided with fodder, while humans had a diet consistently high in protein but with increasing consumption of C3 plants through-time, perhaps related to the emergence of oasis agriculture. While underground and naturally sheltered localities are globally prominent in archaeology and Quaternary science, our work represents the first such combined records for Saudi Arabia and highlight the potential for interdisciplinary studies in caves and lava tubes.

The Impact of Inflammation on Thermal Hyperpnea: Relevance for Heat Stress and Febrile Seizures.

Extreme heat caused by climate change is increasing the transmission of infectious diseases, resulting in a sharp rise in heat-related illness and mortality. Understanding the mechanistic link between heat, inflammation, and disease is thus important for public health. Thermal hyperpnea, and consequent respiratory alkalosis, is crucial in febrile seizures and convulsions induced by heat stress in humans. Here, we address what causes thermal hyperpnea in neonates and how it is affected by inflammation. Transient receptor potential cation channel subfamily V member 1 (TRPV1), a heat-activated channel, is sensitized by inflammation and modulates breathing and thus may play a key role. To investigate whether inflammatory sensitization of TRPV1 modifies neonatal ventilatory responses to heat stress, leading to respiratory alkalosis and an increased susceptibility to hyperthermic seizures, we treated neonatal rats with bacterial LPS, and breathing, arterial pH, in vitro vagus nerve activity, and seizure susceptibility were assessed during heat stress in the presence or absence of a TRPV1 antagonist (AMG-9810) or shRNA-mediated TRPV1 suppression. LPS-induced inflammatory preconditioning lowered the threshold temperature and latency of hyperthermic seizures. This was accompanied by increased tidal volume, minute ventilation, expired CO2, and arterial pH (alkalosis). LPS exposure also elevated vagal spiking and intracellular calcium concentrations in response to hyperthermia. TRPV1 inhibition with AMG-9810 or shRNA reduced the LPS-induced susceptibility to hyperthermic seizures and altered the breathing pattern to fast shallow breaths (tachypnea), making each breath less efficient and restoring arterial pH. These results indicate that inflammation exacerbates thermal hyperpnea-induced respiratory alkalosis associated with increased susceptibility to hyperthermic seizures, primarily mediated by TRPV1 localized to vagus neurons.

Innovations in Stroke Recovery and Rehabilitation: Poststroke Pain.

Pain can be a significant barrier to a stroke survivors' functional recovery and can also lead to a decreased quality of life. Common pain conditions after stroke include headache, musculoskeletal pain, spasticity-related pain, complex regional pain syndrome, and central poststroke pain. This review investigates the evidence of diagnostic and management guidelines for various pain syndromes after stroke and identifies opportunities for future research to advance the field of poststroke pain.

Early switch from intravenous to oral antibiotic therapy in patients with cancer who have low-risk neutropenic sepsis: the EASI-SWITCH RCT.

Background: Neutropenic sepsis is a common complication of systemic anticancer treatment. There is variation in practice in timing of switch to oral antibiotics after commencement of empirical intravenous antibiotic therapy. Objectives: To establish the clinical and cost effectiveness of early switch to oral antibiotics in patients with neutropenic sepsis at low risk of infective complications. Design: A randomised, multicentre, open-label, allocation concealed, non-inferiority trial to establish the clinical and cost effectiveness of early oral switch in comparison to standard care. Setting: Nineteen UK oncology centres. Participants: Patients aged 16 years and over receiving systemic anticancer therapy with fever (≥ 38°C), or symptoms and signs of sepsis, and neutropenia (≤ 1.0 × 109/l) within 24 hours of randomisation, with a Multinational Association for Supportive Care in Cancer score of ≥ 21 and receiving intravenous piperacillin/tazobactam or meropenem for < 24 hours were eligible. Patients with acute leukaemia or stem cell transplant were excluded. Intervention: Early switch to oral ciprofloxacin (750 mg twice daily) and co-amoxiclav (625 mg three times daily) within 12-24 hours of starting intravenous antibiotics to complete 5 days treatment in total. Control was standard care, that is, continuation of intravenous antibiotics for at least 48 hours with ongoing treatment at physician discretion. Main outcome measures: Treatment failure, a composite measure assessed at day 14 based on the following criteria: fever persistence or recurrence within 72 hours of starting intravenous antibiotics; escalation from protocolised antibiotics; critical care support or death. Results: The study was closed early due to under-recruitment with 129 patients recruited; hence, a definitive conclusion regarding non-inferiority cannot be made. Sixty-five patients were randomised to the early switch arm and 64 to the standard care arm with subsequent intention-to-treat and per-protocol analyses including 125 (intervention n = 61 and control n = 64) and 113 (intervention n = 53 and control n = 60) patients, respectively. In the intention-to-treat population the treatment failure rates were 14.1% in the control group and 24.6% in the intervention group, difference = 10.5% (95% confidence interval 0.11 to 0.22). In the per-protocol population the treatment failure rates were 13.3% and 17.7% in control and intervention groups, respectively; difference = 3.7% (95% confidence interval 0.04 to 0.148). Treatment failure predominantly consisted of persistence or recurrence of fever and/or physician-directed escalation from protocolised antibiotics with no critical care admissions or deaths. The median length of stay was shorter in the intervention group and adverse events reported were similar in both groups. Patients, particularly those with care-giving responsibilities, expressed a preference for early switch. However, differences in health-related quality of life and health resource use were small and not statistically significant. Conclusions: Non-inferiority for early oral switch could not be proven due to trial under-recruitment. The findings suggest this may be an acceptable treatment strategy for some patients who can adhere to such a treatment regimen and would prefer a potentially reduced duration of hospitalisation while accepting increased risk of treatment failure resulting in re-admission. Further research should explore tools for patient stratification for low-risk de-escalation or ambulatory pathways including use of biomarkers and/or point-of-care rapid microbiological testing as an adjunct to clinical decision-making tools. This could include application to shorter-duration antimicrobial therapy in line with other antimicrobial stewardship studies. Trial registration: This trial is registered as ISRCTN84288963. Funding: This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 13/140/05) and is published in full in Health Technology Assessment; Vol. 28, No. 14. See the NIHR Funding and Awards website for further award information.

Neutropenic sepsis, or infection with a low white blood cell count, can occur following cancer treatment. Usually patients receive treatment with intravenous antibiotics (antibiotics delivered into a vein) for two or more days. Patients at low risk of complications from their infection may be able to have a shorter period of intravenous antibiotics benefitting both patients and the NHS. The trial compared whether changing from intravenous to oral antibiotics (antibiotics taken by mouth as tablets or liquid) 12­24 hours after starting antibiotic treatment ('early switch') is as effective as usual care. Patients could take part if they had started intravenous antibiotics for low-risk neutropenic sepsis. Patients were randomly allocated to 'early switch' or to usual care. The main outcome measured was treatment failure. Treatment failure happened if fever persisted or recurred despite antibiotics, if patients needed to change antibiotics, if they needed to be re-admitted to hospital or needed to be admitted to intensive care within 14 days or died. We had originally intended that 628 patients would take part, but after review of the design of the study the number needed to take part was revised to 230. We were not able to complete the trial as planned as unfortunately only 129 patients took part. As the trial was smaller than expected we were not able to draw conclusions as to whether 'early switch' is no less effective than usual care. Our findings suggest that 'early switch' might result in a shorter time in hospital initially; however, treatment failure was more likely to occur, meaning some patients had to return to hospital for further antibiotics. There were no differences in side effects and no serious complications from treatment or treatment failure (such as intensive care admission or death) among the 65 patients in the 'early switch' group. Patients were satisfied with 'early switch'. Early switch may be a treatment option for some patients with low-risk neutropenic sepsis who would prefer a shorter duration of hospital admission but accept a risk of needing hospital re-admission.

Rational design of a cyclohexanone dehydrogenase for enhanced α,ß-desaturation and substrate specificity.

The selective α,ß-desaturation of cyclic carbonyl compounds, which are found in the core of many steroid and bioactive molecules, using green chemistry is highly desirable. To achieve this task, we have for the first time described and solved the de novo structure of a member of the cyclohexanone dehydrogenase class of enzymes. The breadth of substrate specificity was investigated by assaying the cyclohexanone dehydrogenase, from Alicycliphilus denitrificans, against several cyclic ketones, lactones and lactams. To investigate substrate binding, a catalytic variant, Y195F, was generated and used to obtain a crystallographic complex with the natural substrate, cyclohexanone. This revealed substrate-active site interactions, as well as the proximity of the cofactor, flavin adenine dinucleotide, and enabled us to propose a mechanistic function to key amino acids. We then used molecular dynamic simulations to guide design to add functionality to the cyclohexanone dehydrogenase enzyme. The resulting W113A variant had overall improved enzyme activity and substrate scope, i.e., accepting the bulkier carbonyl compound, dihydrocoumarin. Structural analysis of the W113A variant revealed a broader, more open active site, which helped explain the modified substrate specificity. This work paves the way for future bespoke regioselective α,ß-desaturation in the synthesis of important bioactive molecules via rational enzyme engineering.

Sirt5-mediated lysine desuccinylation regulates oxidative stress adaptation in Magnaporthe oryzae during host intracellular infection.

Plant pathogenic fungi elaborate numerous detoxification strategies to suppress host reactive oxygen species (ROS), but their coordination is not well-understood. Here, we show that Sirt5-mediated protein desuccinylation in Magnaporthe oryzae is central to host ROS detoxification. SIRT5 encodes a desuccinylase important for virulence via adaptation to host oxidative stress. Quantitative proteomics analysis identified a large number of succinylated proteins targeted by Sirt5, most of which were mitochondrial proteins involved in oxidative phosphorylation, TCA cycle, and fatty acid oxidation. Deletion of SIRT5 resulted in hypersuccinylation of detoxification-related enzymes, and significant reduction in NADPH : NADP+ and GSH : GSSG ratios, disrupting redox balance and impeding invasive growth. Sirt5 desuccinylated thioredoxin Trx2 and glutathione peroxidase Hyr1 to activate their enzyme activity, likely by affecting proper folding. Altogether, this work demonstrates the importance of Sirt5-mediated desuccinylation in controlling fungal process required for detoxifying host ROS during M. oryzae infection.

Hemorrhage at high altitude: impact of sustained hypobaric hypoxia on cerebral blood flow, tissue oxygenation, and tolerance to simulated hemorrhage in humans.

With ascent to high altitude (HA), compensatory increases in cerebral blood flow and oxygen delivery must occur to preserve cerebral metabolism and consciousness. We hypothesized that this compensation in cerebral blood flow and oxygen delivery preserves tolerance to simulated hemorrhage (via lower body negative pressure, LBNP), such that tolerance is similar during sustained exposure to HA vs. low altitude (LA). Healthy humans (4F/4 M) participated in LBNP protocols to presyncope at LA (1130 m) and 5-7 days following ascent to HA (3800 m). Internal carotid artery (ICA) blood flow, cerebral delivery of oxygen (CDO2) through the ICA, and cerebral tissue oxygen saturation (ScO2) were determined. LBNP tolerance was similar between conditions (LA: 1276 ± 304 s vs. HA: 1208 ± 306 s; P = 0.58). Overall, ICA blood flow and CDO2 were elevated at HA vs. LA (P ≤ 0.01) and decreased with LBNP under both conditions (P < 0.0001), but there was no effect of altitude on ScO2 responses (P = 0.59). Thus, sustained exposure to hypobaric hypoxia did not negatively impact tolerance to simulated hemorrhage. These data demonstrate the robustness of compensatory physiological mechanisms that preserve human cerebral blood flow and oxygen delivery during sustained hypoxia, ensuring cerebral tissue metabolism and neuronal function is maintained.

Personalising intravenous to oral antibiotic switch decision making through fair interpretable machine learning.

Antimicrobial resistance (AMR) and healthcare associated infections pose a significant threat globally. One key prevention strategy is to follow antimicrobial stewardship practices, in particular, to maximise targeted oral therapy and reduce the use of indwelling vascular devices for intravenous (IV) administration. Appreciating when an individual patient can switch from IV to oral antibiotic treatment is often non-trivial and not standardised. To tackle this problem we created a machine learning model to predict when a patient could switch based on routinely collected clinical parameters. 10,362 unique intensive care unit stays were extracted and two informative feature sets identified. Our best model achieved a mean AUROC of 0.80 (SD 0.01) on the hold-out set while not being biased to individuals protected characteristics. Interpretability methodologies were employed to create clinically useful visual explanations. In summary, our model provides individualised, fair, and interpretable predictions for when a patient could switch from IV-to-oral antibiotic treatment. Prospectively evaluation of safety and efficacy is needed before such technology can be applied clinically.