Ten-year statewide cross-sectional review of pediatric sinogenic intracranial abscess and empyema in Queensland, Australia: microbial profile before and after COVID-19.

OBJECTIVE: Sinogenic intracranial infections in children, such as subdural empyema or intracranial abscess, are a rare disease process with significant associated morbidity. Recent literature has suggested that there may have been an increase in frequency of these infections following the COVID-19 pandemic, but the literature has been conflicting, perhaps related to the heterogenous management of COVID-19 lockdowns in various states and differences in data capture between methods. The collection of statewide Australian data overcomes these limitations by capturing a comprehensive sample though the public healthcare system of patients who were subject to a homogeneous statewide approach to public health policy during the COVID-19 pandemic (population 5.6 million, including 1.3 million children). The objective of this study was to present population-level data to address the question of whether the incidence of intracranial infections changed in pediatric patients before and after the COVID-19 pandemic. METHODS: The authors present a retrospective 10-year statewide description of sinogenic intracranial infections in Queensland, Australia. A comparison was made between the incidence and microbiological profile before and after the onset of COVID-19 lockdowns on March 22, 2020. RESULTS: Forty-four pediatric intracranial infections undergoing neurosurgical intervention were identified within the review period. After exclusion of postsurgical and cardioembolic causes, 33 sinogenic intracranial infections were included (16 before and 17 after 2020, with a mean annualized incidence of 0.25 vs 0.37 cases per 100,000 children, respectively; p > 0.05). The most frequent organisms identified were Streptococcus milleri (n = 19), polymicrobial (n = 4), and S. aureus (n = 3). No significant differences in antimicrobial profile, susceptibility, parenchymal involvement, or clinical outcome were identified between the pre- and post-COVID-19 groups. CONCLUSIONS: No statistically significant differences in the epidemiology of pediatric intracranial infection have occurred in the state of Queensland, Australia, before and after March 22, 2020, and the COVID-19 pandemic.

Minimally invasive far lateral tubular microdiscectomy: surgical technique and case series of 176 patients.

BACKGROUND: Far lateral (extraforaminal) disc herniations comprise approximately 10% of symptomatic lumbar disc herniations. They represent operative challenges due to accessibility and surgical unfamiliarity. Surgical strategies in the past have included open discectomy and posterior lumbar interbody fusion. Tubular microdiscectomies have gained traction due to their minimally invasive advantages, including reduced morbidity, pain and length of hospital stay. METHODS: We report our retrospective single institution consecutive case series of tubular far lateral microdiscectomies. One hundred and seventy-six patients were operated on over an eight-year period. Clinical outcomes were assessed after institutional ethics approval. We additionally describe our surgical technique with an illustrative video case. RESULTS: Over a mean follow-up of 21 weeks, 77% of patients had good or excellent clinical outcomes according to the MacNab criteria. 12% of patients underwent reoperation at the index level for symptom recurrence or persistence. Mean length of hospital stay was 1.3 days. There was a 1% rate of both postoperative haematoma and infection. Mean operation duration was 86 minutes. CONCLUSION: This case series represents the largest currently reported in the literature. Minimally invasive microdiscectomies performed through tubes allow for precise localisation, reduced tissue disruption and favourable clinical outcomes. Our results appear consistent with a review of the literature, demonstrating the safety and efficacy of this approach.

A lactate-dependent shift of glycolysis mediates synaptic and cognitive processes in male mice.

Astrocytes control brain activity via both metabolic processes and gliotransmission, but the physiological links between these functions are scantly known. Here we show that endogenous activation of astrocyte type-1 cannabinoid (CB1) receptors determines a shift of glycolysis towards the lactate-dependent production of D-serine, thereby gating synaptic and cognitive functions in male mice. Mutant mice lacking the CB1 receptor gene in astrocytes (GFAP-CB1-KO) are impaired in novel object recognition (NOR) memory. This phenotype is rescued by the gliotransmitter D-serine, by its precursor L-serine, and also by lactate and 3,5-DHBA, an agonist of the lactate receptor HCAR1. Such lactate-dependent effect is abolished when the astrocyte-specific phosphorylated-pathway (PP), which diverts glycolysis towards L-serine synthesis, is blocked. Consistently, lactate and 3,5-DHBA promoted the co-agonist binding site occupancy of CA1 post-synaptic NMDA receptors in hippocampal slices in a PP-dependent manner. Thus, a tight cross-talk between astrocytic energy metabolism and gliotransmission determines synaptic and cognitive processes.

Surgeon- and hospital-level variation in wait times for scheduled non-urgent surgery in Ontario, Canada: A cross-sectional population-based study.

BACKGROUND: Canadian health systems fare poorly in providing timely access to elective surgical care, which is crucial for quality, trust, and satisfaction. METHODS: We conducted a cross-sectional analysis of surgical wait times for adults receiving non-urgent cataract surgery, knee arthroplasty, hip arthroplasty, gallbladder surgery, and non-cancer uterine surgery in Ontario, Canada, between 2013 and 2019. We obtained data from the Wait Times Information System (WTIS) database. Inter- and intra-hospital and surgeon variations in wait time were described graphically with caterpillar plots. We used non-nested 3-level hierarchical random effects models to estimate variation partition coefficients, quantifying the proportion of wait time variance attributable to surgeons and hospitals. RESULTS: A total of 942,605 procedures at 107 healthcare facilities, conducted by 1,834 surgeons, were included in the analysis. We observed significant intra- and inter-provider variations in wait times across all five surgical procedures. Inter-facility median wait time varied between six-fold for gallbladder surgery and 15-fold for knee arthroplasty. Inter-surgeon variation was more pronounced, ranging from a 17-fold median wait time difference for cataract surgery to a 216-fold difference for non-cancer uterine surgery. The proportion of variation in wait times attributable to facilities ranged from 6.2% for gallbladder surgery to 23.0% for cataract surgery. In comparison, surgeon-related variation ranged from 16.0% for non-cancer uterine surgery to 28.0% for cataract surgery. IMPLICATIONS: There is extreme variability in surgical wait times for five common, high-volume, non-urgent surgical procedures. Strategies to address surgical wait times must address the variation between service providers through better coordination of supply and demand. Approaches such as single-entry models could improve surgical system performance.

Special Section Guest Editorial: Molecular Neurophotonics.

The editorial introduces the Special Section on Molecular Neurophotonics.

Prospective, international, multisite comparison of platelet isolation techniques for genome-wide transcriptomics: communication from the SSC of the ISTH.

Genome-wide platelet transcriptomics is increasingly used to uncover new aspects of platelet biology and as a diagnostic and prognostic tool. Nevertheless, platelet isolation methods for transcriptomic studies are not standardized, introducing challenges for cross-study comparisons, data integration, and replication. In this prospective multicenter study, called "Standardizing Platelet Transcriptomics for Discovery, Diagnostics, and Therapeutics in the Thrombosis and Hemostasis Community (STRIDE)" by the International Society on Thrombosis and Haemostasis Scientific and Standardization Committees, we assessed how 3 of the most commonly used platelet isolation protocols influence metrics from next-generation bulk RNA sequencing and functional assays. Compared with washing alone, more stringent removal of leukocytes by anti-CD45 beads or PALL filters resulted in a sufficient quantity of RNA for next-generation sequencing and similar quality of RNA sequencing metrics. Importantly, stringent removal of leukocytes resulted in the lower relative expression of known leukocyte-specific genes and the higher relative expression of known platelet-specific genes. The results were consistent across enrolling sites, suggesting that the techniques are transferrable and reproducible. Moreover, all 3 isolation techniques did not influence basal platelet reactivity, but agonist-induced integrin αIIbß3 activation is reduced by anti-CD45 bead isolation compared with washing alone. In conclusion, the isolation technique chosen influences genome-wide transcriptional and functional assays in platelets. These results should help the research community make informed choices about platelet isolation techniques in their own platelet studies.

Improving Clinical Registry Data Quality via Linkage With Survival Data From State-Based Population Registries.

PURPOSE: Real-world data (RWD) collected on patients treated as part of routine clinical care form the basis of cancer clinical registries. Capturing accurate death data can be challenging, with inaccurate survival data potentially compromising the integrity of registry-based research. Here, we explore the utility of data linkage (DL) to state-based registries to enhance the capture of survival outcomes. METHODS: We identified consecutive adult patients with brain tumors treated in the state of Victoria from the Brain Tumour Registry Australia: Innovation and Translation (BRAIN) database, who had no recorded date of death and no follow-up within the last 6 months. Full name and date of birth were used to match patients in the BRAIN registry with those in the Victorian Births, Deaths and Marriages (BDM) registry. Overall survival (OS) outcomes were compared pre- and post-DL. RESULTS: Of the 7,346 clinical registry patients, 5,462 (74%) had no date of death and no follow-up recorded within the last 6 months. Of the 5,462 patients, 1,588 (29%) were matched with a date of death in BDM. Factors associated with an increased number of matches were poor prognosis tumors, older age, and social disadvantage. OS was significantly overestimated pre-DL compared with post-DL for the entire cohort (pre- v post-DL: hazard ratio, 1.43; P < .001; median, 29.9 months v 16.7 months) and for most individual tumor types. This finding was present independent of the tumor prognosis. CONCLUSION: As revealed by linkage with BDM, a high proportion of patients in a brain cancer clinical registry had missing death data, contributed to by informative censoring, inflating OS calculations. DL to pertinent registries on an ongoing basis should be considered to ensure accurate reporting of survival data and interpretation of RWD outcomes.

Development of an miRFP680-Based Fluorescent Calcium Ion Biosensor Using End-Optimized Transposons.

The development of new or improved single fluorescent protein (FP)-based biosensors (SFPBs), particularly those with excitation and emission at near-infrared wavelengths, is important for the continued advancement of biological imaging applications. In an effort to accelerate the development of new SFPBs, we report modified transposons for the transposase-based creation of libraries of FPs randomly inserted into analyte binding domains, or vice versa. These modified transposons feature ends that are optimized to minimize the length of the linkers that connect the FP to the analyte binding domain. We rationalized that shorter linkers between the domains should result in more effective allosteric coupling between the analyte binding-dependent conformational change in the binding domain and the fluorescence modulation of the chromophore of the FP domain. As a proof of concept, we employed end-modified Mu transposons for the discovery of SFPB prototypes based on the insertion of two circularly permuted red FPs (mApple and FusionRed) into binding proteins for l-lactate and spermidine. Using an analogous approach, we discovered calcium ion (Ca2+)-specific SFPBs by random insertion of calmodulin (CaM)-RS20 into miRFP680, a particularly bright near-infrared (NIR) FP based on a biliverdin (BV)-binding fluorescent protein. Starting from an miRFP680-based Ca2+ biosensor prototype, we performed extensive directed evolution, including under BV-deficient conditions, to create highly optimized biosensors designated the NIR-GECO3 series. We have extensively characterized the NIR-GECO3 series and explored their utility for biological Ca2+ imaging. The methods described in this work will serve to accelerate SFPB development and open avenues for further exploration and optimization of SFPBs across a spectrum of biological applications.

Aging-related alterations in mechanistic target of rapamycin signaling promote platelet hyperreactivity and thrombosis.

BACKGROUND: Aging is an independent risk factor for the development of cardiovascular, thrombotic, and other chronic diseases. However, mechanisms of platelet hyperactivation in aging remain poorly understood. OBJECTIVES: Here, we examine whether and how aging alters intracellular signaling in platelets to support platelet hyperactivity and thrombosis. METHODS: Quantitative mass spectrometry with tandem mass tag labeling systematically measured protein phosphorylation in platelets from healthy aged (>65 years) and young human (<45 years) subjects. The role of platelet mechanistic target of rapamycin (mTOR) in aging-induced platelet hyperreactivity was assessed using pharmacologic mTOR inhibition and a platelet-specific mTOR-deficient mouse model (mTORplt-/-). RESULTS: Quantitative phosphoproteomics uncovered differential site-specific protein phosphorylation within mTOR, Rho GTPase, and MAPK pathways in platelets from aged donors. Western blot confirmed constitutive activation of the mTOR pathway in platelets from both aged humans and mice, which was associated with increased aggregation compared with that in young controls. Inhibition of mTOR with either Torin 1 in aged humans or genetic deletion in aged mice reversed platelet hyperreactivity. In a collagen-epinephrine pulmonary thrombosis model, aged wild-type (mTORplt+/+) mice succumbed significantly faster than young controls, while time to death of aged mTORplt-/- mice was similar to that of young mTORplt+/+ mice. Mechanistically, we noted increased Rac1 activation and levels of mitochondrial reactive oxygen species in resting platelets from aged mice, as well as increased p38 phosphorylation upstream of thromboxane generation following agonist stimulation. CONCLUSION: Aging-related changes in mTOR phosphorylation enhance Rac1 and p38 activation to enhance thromboxane generation, platelet hyperactivity, and thrombosis.

An Experimental Infection Model in Sheep and Goats to Evaluate Salmonella Colonization in Deep Tissue Lymph Nodes and after Carcass Vascular Rinsing with Bacteriophages in Goats.

An animal infection model was evaluated on sheep and goats to confirm which species infected with Salmonella enterica serovar Enteritidis C StR (SE13) would provide a consistent and high frequency of Salmonella colonization in lymph nodes (LNs) without causing undue animal morbidity. Sheep and goats (n = 5) were intradermally inoculated with Salmonella, postincubated for 7 days, and euthanized. Superficial cervical, medial iliac, subiliac, mammary, and popliteal LNs were excised from each carcass. Goat LNs had approximately 53% greater Salmonella level compared to sheep. Also, Salmonella was inconsistently recovered from the sheep LNs. Thus, goats were selected to determine the ability of carcass vascular rinsing (with and without bacteriophages) to reduce Salmonella in infected LNs. Goats with similar characteristics were grouped together before being randomly assigned to 3 postharvest treatments; control (CN, not vascularly rinsed; n = 10), vascularly rinsed with a standard Rinse & Chill® solution (RC; 98.5% water and a blend of saccharides and phosphates; n = 10), or vascularly rinsed with a standard Rinse & Chill® solution plus the addition of bacteriophages (BP; n = 10). Rinse & Chill® system was able to successfully deliver a mean 7.0 log PFU/g to the S. Enteritidis-infected LNs (mean 3.5 log CFU/g). However, neither Rinse & Chill® without bacteriophages nor with bacteriophages caused Salmonella reduction (P > 0.05) compared to the nonrinsed goat carcasses.

Blue-shifted genetically encoded Ca2+ indicator with enhanced two-photon absorption.

Significance: Genetically encoded calcium ion (Ca2+) indicators (GECIs) are powerful tools for monitoring intracellular Ca2+ concentration changes in living cells and model organisms. In particular, GECIs have found particular utility for monitoring the transient increase of Ca2+ concentration that is associated with the neuronal action potential. However, the palette of highly optimized GECIs for imaging of neuronal activity remains relatively limited. Expanding the selection of available GECIs to include new colors and distinct photophysical properties could create new opportunities for in vitro and in vivo fluorescence imaging of neuronal activity. In particular, blue-shifted variants of GECIs are expected to have enhanced two-photon brightness, which would facilitate multiphoton microscopy. Aim: We describe the development and applications of T-GECO1-a high-performance blue-shifted GECI based on the Clavularia sp.-derived mTFP1. Approach: We use protein engineering and extensive directed evolution to develop T-GECO1. We characterize the purified protein and assess its performance in vitro using one-photon excitation in cultured rat hippocampal neurons, in vivo using one-photon excitation fiber photometry in mice, and ex vivo using two-photon Ca2+ imaging in hippocampal slices. Results: The Ca2+-bound state of T-GECO1 has an excitation peak maximum of 468 nm, an emission peak maximum of 500 nm, an extinction coefficient of 49,300 M-1 cm-1, a quantum yield of 0.83, and two-photon brightness approximately double that of EGFP. The Ca2+-dependent fluorescence increase is 15-fold, and the apparent Kd for Ca2+ is 82 nM. With two-photon excitation conditions at 850 nm, T-GECO1 consistently enabled the detection of action potentials with higher signal-to-noise (SNR) than a late generation GCaMP variant. Conclusions: T-GECO1 is a high-performance blue-shifted GECI that, under two-photon excitation conditions, provides advantages relative to late generation GCaMP variants.

Heterozygous Eif4nif1 Stop Gain Mice Replicate the Primary Ovarian Insufficiency Phenotype in Women.

We created the c.1286C>G stop-gain mutation found in a family with primary ovarian insufficiency (POI) at age 30 years. The Eif4enif1 C57/Bl6 transgenic mouse model contained a floxed exon 10-19 cassette with a conditional knock-in cassette containing the c.1286C>G stop-gain mutation in exon 10. The hybrid offspring of CMV- Cre mice with Eif4enif1 WT/flx mice were designated Eif4enif1 WT/ Δ for simplicity. A subset of female heterozygotes ( Eif4enif1 WT/ Δ ) had no litters. In those with litters, the final litter was earlier (5.4±2.6 vs. 10.5±0.7 months; p=0.02). Heterozygous breeding pair ( Eif4enif1 WT/ Δ x Eif4enif1 WT/ Δ ) litter size was 60% of WT litter size (3.9±2.0 vs. 6.5±3.0 pups/litter; p <0.001). The genotypes were 35% Eif4enif1 WT/flx and 65% Eif4enif1 WT/ Δ , with no homozygotes. Homozygote embryos did not develop beyond the 4-8 cell stage. The number of follicles in ovaries from Eif4enif1 WT/ Δ mice was lower starting at the primordial (499±290 vs. 1445±381) and primary follicle stage (1069±346 vs. 1450±193) on day 10 (p<0.05). The preantral follicle number was lower starting on day 21 (213±86 vs. 522±227; p<0.01). Examination of ribosome protected mRNAs (RPR) demonstrated altered mRNA expression. The Eif4enif1 stop-gain mice replicate the POI phenotype in women. The unique mouse model provides a platform to study regulation of protein translation across oocyte and embryo development in mammals.

High-Performance Genetically Encoded Green Fluorescent Biosensors for Intracellular l-Lactate.

l-Lactate is a monocarboxylate produced during the process of cellular glycolysis and has long generally been considered a waste product. However, studies in recent decades have provided new perspectives on the physiological roles of l-lactate as a major energy substrate and a signaling molecule. To enable further investigations of the physiological roles of l-lactate, we have developed a series of high-performance (ΔF/F = 15 to 30 in vitro), intensiometric, genetically encoded green fluorescent protein (GFP)-based intracellular l-lactate biosensors with a range of affinities. We evaluated these biosensors in cultured cells and demonstrated their application in an ex vivo preparation of Drosophila brain tissue. Using these biosensors, we were able to detect glycolytic oscillations, which we analyzed and mathematically modeled.

An optogenetic method for the controlled release of single molecules.

We developed a system for optogenetic release of single molecules in cells. We confined soluble and transmembrane proteins to the Golgi apparatus via a photocleavable protein and released them by short pulses of light. Our method allows for a light dose-dependent delivery of functional proteins to the cytosol and plasma membrane in amounts compatible with single-molecule imaging, greatly simplifying access to single-molecule microscopy of any protein in live cells. We were able to reconstitute ion conductance by delivering BK and LRRC8/volume-regulated anion channels to the plasma membrane. Finally we were able to induce NF-kB signaling in T lymphoblasts stimulated by interleukin-1 by controlled release of a signaling protein that had been knocked out. We observed light-induced formation of functional inflammatory signaling complexes that triggered phosphorylation of the inhibitor of nuclear factor kappa-B kinase only in activated cells. We thus developed an optogenetic method for the reconstitution and investigation of cellular function at the single-molecule level.

Standardised Measurements for Monitoring and Comparing Multiphoton Microscope Systems.

The goal of this protocol is to enable better characterisation of multiphoton microscopy hardware across a large user base. The scope of this protocol is purposefully limited to focus on hardware, touching on software and data analysis routines only where relevant. The intended audiences are scientists using and building multiphoton microscopes in their laboratories. The goal is that any scientist, not only those with optical expertise, can test whether their multiphoton microscope is performing well and producing consistent data over the lifetime of their system.

Differences in testing for drugs of abuse amongst racial and ethnic groups at children's hospitals.

OBJECTIVES: Racial and ethnic differences in drug testing have been described among adults and newborns. Less is known regarding testing patterns among children and adolescents. We sought to describe the association between race and ethnicity and drug testing at US children's hospitals. We hypothesized that non-Hispanic White children undergo drug testing less often than children from other groups. METHODS: We conducted a retrospective cohort study of emergency department (ED)-only encounters and hospitalizations for children diagnosed with a condition for which drug testing may be indicated (abuse or neglect, burns, malnutrition, head injury, vomiting, altered mental status or syncope, psychiatric, self-harm, and seizure) at 41 children's hospitals participating in the Pediatric Health Information System during 2018 and 2021. We compared drug testing rates among (non-Hispanic) Asian, (non-Hispanic) Black, Hispanic, and (non-Hispanic) White children overall, by condition and patient cohort (ED-only vs. hospitalized) and across hospitals. RESULTS: Among 920,755 encounters, 13.6% underwent drug testing. Black children were tested at significantly higher rates overall (adjusted odds ratio [aOR]: 1.18; 1.05-1.33) than White children. Black-White testing differences were observed in the hospitalized cohort (aOR: 1.42; 1.18-1.69) but not among ED-only encounters (aOR: 1.07; 0.92-1.26). Asian, Hispanic, and White children underwent testing at similar rates. Testing varied by diagnosis and across hospitals. CONCLUSIONS: Hospitalized Black children were more likely than White children to undergo drug testing at US children's hospitals, though this varied by diagnosis and hospital. Our results support efforts to better understand and address healthcare disparities, including the contributions of implicit bias and structural racism.

[Development of fluorescent imaging sensors based on proteins].

Fluorescent imaging sensors based on genetically-encoded and biocompatible proteins have become important tools in medical and biological research due to their high spatiotemporal resolution and ease of use. Protein engineering has led to the development of imaging sensors that visualize changes in the concentration of various target molecules/ions, such as calcium ions. In addition, the development of chemigenetic sensors based on complexes of proteins and synthetic molecules has been gaining momentum in recent years. In this article, the latest research trends in the development of these imaging sensors are introduced, with focus on the sensors developed by our group.

Stereoelectroencephalography: a review of complications and outcomes in a new Australian centre.

BACKGROUND: Surgical management of refractory focal epilepsy requires preoperative localisation of the epileptogenic zone (EZ). To augment noninvasive studies, stereoelectroencephalography (SEEG) is being increasingly adopted as a form of intracranial monitoring. AIMS: This study aimed to determine the rate of complications for patients undergoing SEEG and to report the success of SEEG with regard to EZ detection and seizure outcome following definitive surgery. METHODS: A retrospective cohort design investigated all cases of SEEG at our institution. Surgical, anaesthetic and medical complications with subsequent epilepsy surgery and seizure outcome data were extracted from medical records. Multivariate logistic regression was used to investigate the relationship between both the number of electrodes per patient and the duration of SEEG recording with the rate of complications. RESULTS: Sixty-four patients with 66 implantations were included. Headache was the most common complication (n = 54, 82%). There were no major surgical or medical complications. Two anaesthetic complications occurred. EZ localisation was successful in 63 cases (95%). Curative intent surgery was performed in 39 patients (59%) and 23 patients achieved an Engel class I outcome (59% of those undergoing surgery). The number of electrodes and duration of recording were not associated with complications. CONCLUSIONS: No patients in our series experienced major surgical or medical complications and we have highlighted the challenges associated with neuroanaesthesia in SEEG. Our complication rates and seizure outcomes are equivalent to published literature indicating that this technique can be successfully established in newer centres using careful case selection. Standardised reporting of SEEG complications should be adopted.