A mass cytometry method pairing T cell receptor and differentiation state analysis.

T cell antigen receptor (TCR) recognition followed by clonal expansion is a fundamental feature of adaptive immune responses. Here, we present a mass cytometric (CyTOF) approach to track T cell responses by combining antibodies for specific TCR Vα and Vß chains with antibodies against T cell activation and differentiation proteins in mice. This strategy identifies expansions of CD8+ and CD4+ T cells expressing specific Vß and Vα chains with varying differentiation states in response to Listeria monocytogenes, tumors and respiratory influenza infection. Expanded T cell populations expressing Vß chains could be directly linked to the recognition of specific antigens from Listeria, tumor cells or influenza. In the setting of influenza infection, we found that common therapeutic approaches of intramuscular vaccination or convalescent serum transfer altered the TCR diversity and differentiation state of responding T cells. Thus, we present a method to monitor broad changes in TCR use paired with T cell phenotyping during adaptive immune responses.

A Phase I trial of Non-invasive Ventilation and seizure prophylaxis with levetiracetam In Children with Cerebral Malaria Trial (NOVICE-M Trial).

Background: African children with cerebral malaria and seizures caused Plasmodium falciparum are at greater risk of poor outcomes including death and neurological sequelae. The agonal events are severe hypoventilation and respiratory arrest often triggered by seizures. We hypothesised that prophylactic anti-seizure medication (ASM) could avert 'spikes' of intracranial pressure during or following seizures and that adequate ventilation could be supported by biphasic Cuirass Ventilation (BCV) which requires no intubation. Methods: A Phase I trial conducted in Kilifi, Kenya designed to provide data on safety, feasibility and preliminary data on seizure control using prophylactic ASM (levetiracetam) and BCV as non-invasive ventilatory support in children with cerebral malaria. Children aged 3 months to 12-years hospitalised with P falciparum malaria (positive rapid diagnostic test or a malaria slide), a Blantyre Coma Score ≤2 and a history of acute seizures in this illness are eligible for the trial. In a phased evaluation we will study i) BCV alone for respiratory support (n=10); ii) prophylactic LVT: 40mg/kg loading dose then 30mg/kg every 12 hours given via nasogastric tube for 72 hours (or until fully conscious) plus BCV support (n=10) and; iii) prophylactic LVT: 60mg/kg loading dose then 45mg/kg every 12 hours given via nasogastric tube for 72 hours (or until fully conscious) plus BCV support (n=10). Primary outcome measure: cumulative time with a clinically detected seizures or number of observed seizures over 36 hours. Secondary outcomes will be assessed by feasibility or ability to implement BCV, and recovery from coma within 36 hours. Safety endpoints include: aspiration during admission; death at 28 days and 180 days; and de-novo neurological impairments at 180 days. Conclusions: This is a Phase I trial largely designed to test the feasibility, tolerability and safety of using non-invasive ventilatory support and LVT prophylaxis in cerebral malaria. Registration: ISRCTN76942974 (5.02.2019); PACTR202112749708968 (20.12.2021).

Unfortunately, children with cerebral malaria continue to have very poor outcomes including severe hypoventilation and respiratory arrest (i.e. breathing is too slow or stops) during hospitalization which is often triggered by seizures. We will explore the potential benefits of a special type of ventilation that applies suction or negative pressure to the chest (meaning keeping children breathing by pushing air in and out of their lungs) in combination with anticonvulsants given before children have had any fits We will use a device called biphasic Cuirass Ventilation (BCV) that can be used by non-specialists to help children breath. BCV applies both negative and positive pressure to the chest, covering both inspiration (breathing in) and expiration (breathing out) phases of breathing, which is more appropriate for periods of when the breathing is too slow or stops for a period of time. We will also use an anticonvulsant drug, called levetiracetam to prevent seizures. It has been safely used in Malawian children and shown to improve outcomes. This will be given directly into the stomach via a nasogastric tube (tubes down the nose into the stomach) The study will be carried out at Kilifi County Hospital, Kenya and plans to enrol 30 children aged 3 months to 12 years with cerebral malaria and a positive malaria test The first ten children with have the BCV device only to assist respiration until they recover from their coma. The next twenty children in the trial will have the BCV device in addition with anticonvulsants given before children have had any fits as a preventive strategy to stop fits. All children will have regular monitoring during the period of coma/ventilation and will be followed up on days 28 and 180. The study aims to generate feasibility and safety data to support future trials.

Tocilizumab unfolds colo-protective and immunomodulatory effect in experimentally induced ulcerative colitis via mitigating autophagy and ER stress signaling.

Ulcerative colitis (UC) is an idiopathic, chronic, relapsing inflammatory bowel disease (IBD), characterized by chronic inflammation of the gastrointestinal tract. The pathophysiology of UC is complicated and involves several factors including immune, genetic, and environmental factors. Recently, a huge amount of research has concentrated on the role of interleukins including interleukin-6 (IL-6) in its pathophysiology. Thus, this study aims to examine the colo-protective and immunomodulatory effect of Tocilizumab (TCZ) in an experimental model of dextran sulfate sodium (DSS) induced UC. In the current study, we analyzed the inflammatory, immunomodulatory, apoptotic, autophagy, and endoplasmic reticulum (ER) stress markers and other clinical features including stool consistency, rectal bleeding, and edema markers in rats. Our results showed that induction of colitis caused bloody diarrhea and increased IL-6 levels. Treatment with TCZ significantly ameliorated DSS-induced injury via decreasing inflammatory markers of colon injury (IL-6), signal transducer and activator of transcription-3 (STAT-3), and C-reactive protein (CRP). Furthermore, TCZ attenuated the apoptotic marker (caspase-3), and down-regulated endoplasmic reticulum stress sensor proteins (inositol- requiring transmembrane kinase endonuclease-1 (IRE-1) and activated transcription factor-6 (ATF-6)) and autophagy proteins (autophagy-related 16-like protein 1 (ATG16L1) and nucleotide-binding oligomerization domain-containing protein-2 (NOD2)), as compared to DSS group. Altogether, the current data suggest TCZ to be a promising protective therapy against UC.

The seasonal distribution of immune thrombotic thrombocytopenic purpura is influenced by geography: Epidemiologic findings from a multi-center analysis of 719 disease episodes.

Prior studies have suggested that immune thrombotic thrombocytopenic purpura (iTTP) may display seasonal variation; however, methodologic limitations and sample sizes have diminished the ability to perform a rigorous assessment. This 5-year retrospective study assessed the epidemiology of iTTP and determined whether it displays a seasonal pattern. Patients with both initial and relapsed iTTP (defined as a disintegrin and metalloprotease with thrombospondin type motifs 13 activity <10%) from 24 tertiary centers in Australia, Canada, France, Greece, Italy, Spain, and the US were included. Seasons were defined as: Northern Hemisphere-winter (December-February); spring (March-May); summer (June-August); autumn (September-November) and Southern Hemisphere-winter (June-August); spring (September-November); summer (December-February); autumn (March-May). Additional outcomes included the mean temperature in months with and without an iTTP episode at each site. A total of 583 patients experienced 719 iTTP episodes. The observed proportion of iTTP episodes during the winter was significantly greater than expected if equally distributed across seasons (28.5%, 205/719, 25.3%-31.9%; p = .03). Distance from the equator and mean temperature deviation both positively correlated with the proportion of iTTP episodes during winter. Acute iTTP episodes were associated with the winter season and colder temperatures, with a second peak during summer. Occurrence during winter was most pronounced at sites further from the equator and/or with greater annual temperature deviations. Understanding the etiologies underlying seasonal patterns of disease may assist in discovery and development of future preventative therapies and inform models for resource utilization.

Predictors of distant metastatic recurrence in head and neck cutaneous squamous cell carcinoma with lymph node metastases treated with curative intent: A multicenter study.

BACKGROUND: We aimed to identify predictors of distant metastatic recurrence (DMR) in patients with head and neck cutaneous squamous cell carcinoma (HNcSCC) with nodal metastases treated with curative intent. METHODS: Predictors of DMR were identified using Cox regression in a multicenter study of 1151 patients. RESULTS: The 5-year risk of DMR was 9.6%. On multivariate analysis, immunosuppression (HR 2.93; 95% CI: 1.70-5.05; p < 0.001), nodal size >6 cm [versus ≤3 cm (HR 2.77; 95% CI: 1.09-7.03; p = 0.032)], ≥5 nodal metastases [versus 1-2 (HR 2.79; 95% CI: 1.63-4.78; p < 0.001)], and bilateral disease (HR 3.11; 95% CI: 1.40-6.90; p = 0.005) predicted DMR. A DMR risk score was developed that stratified risk from 6.6% (no risk factors) to 100% (≥3 risk factors) (p < 0.001). CONCLUSIONS: The risk of DMR in nodal metastatic HNcSCC increases with immunosuppression, nodal size >6 cm, ≥5 nodal metastases, and bilateral disease. A simple DMR risk score estimated prior to treatment may be clinically useful.

Healthcare workers' experiences protecting themselves and their families during the COVID-19 pandemic in 2020-2021.

We characterized experiences and strategies used by frontline healthcare workers to prevent severe-acute-respiratory-syndrome-related coronavirus transmission at work and to household members during the coronavirus disease pandemic. Alongside an online questionnaire (n = 234), remote semi-structured interviews (n = 23: 15 clinicians, 8 non-clinicians) were conducted in 2021. Mitigation challenges and facilitators were identified from data to represent experiences as a process considering the before, during, and after work shifts. Journey mapping was utilized to visually describe how healthcare workers experienced the stages of the work environment, leaving work, commuting home, and the home environment, and strategies implemented to stay safe. Major facilitators included the uptake of coronavirus disease vaccines and testing, information regarding virus transmission, and adequate personal protective equipment. The most critical challenges identified included a lack of designated areas for end-of-day disinfection, changing rooms, showers, and lockers in the leaving work stage. Psychosocial and environmental factors must be considered in future hospital pandemic preparations.

Stimulating implementation of clinical practice guidelines in hospital care from a central guideline organization perspective: A systematic review.

BACKGROUND: The uptake of guidelines in care is inconsistent. This review focuses on guideline implementation strategies used by guideline organizations (governmental agencies, scientific/professional societies and other umbrella organizations), experienced implementation barriers and facilitators and impact of their implementation efforts. METHODS: We searched PUBMED, EMBASE and CINAHL and conducted snowballing. Eligibility criteria included guidelines focused on hospital care and OECD countries. Study quality was assessed using the Mixed Methods Appraisal Tool. We used framework analysis, narrative synthesis and summary statistics. RESULTS: Twenty-six articles were included. Sixty-two implementation strategies were reported, used in different combinations and ranged between 1 and 16 strategies per initiative. Most frequently reported strategies were educational session(s) and implementation supporting materials. The most commonly reported barrier and facilitator were respectively insufficient healthcare professionals' time and resources; and guideline's credibility, evidence base and relevance. Eighty-five percent of initiatives that measured impact achieved improvements in adoption, knowledge, behavior and/or clinical outcomes. No clear optimal approach for improving guideline uptake and impact was found. However, we found indications that employing multiple active implementation strategies and involving external organizations and hospital staff were associated with improvements. CONCLUSION: Guideline organizations employ diverse implementation strategies and encounter multiple barriers and facilitators. Our study uncovered potential effective implementation practices. However, further research is needed on effective tailoring of implementation approaches to increase uptake and impact of guidelines.

In-Silico Analyses of Molecular Force Sensors for Mechanical Characterization of Biological Systems.

Mechanical forces play key roles in biological processes such as cell migration and sensory perception. In recent years molecular force sensors have been developed as tools for in situ force measurements. Here we use all-atom steered molecular dynamics simulations to predict and study the relationship between design parameters and mechanical properties for three types of molecular force sensors commonly used in cellular biological research: two peptide- and one DNA-based. The peptide-based sensors consist of a pair of fluorescent proteins, which can undergo Förster resonance energy transfer (FRET), linked by spider silk (GPGGA)n or synthetic (GGSGGS)n disordered regions. The DNA-based sensor consists of two fluorophore-labeled strands of DNA that can be unzipped or sheared upon force application with a FRET signal as readout of dissociation. We simulated nine sensors, three of each kind. After equilibration, flexible peptide linkers of three different lengths were stretched by applying forces to their N- and C-terminal Cα atoms in opposite directions. Similarly, we equilibrated a DNA-based sensor and pulled on the phosphate atom of the terminal guanine of one strand and a selected phosphate atom on the other strand in the opposite direction. These simulations were performed at constant velocity (0.01 nm/ns - 10 nm/ns) and constant force (10 pN - 500 pN) for all versions of the sensors. Our results show how the force response of these sensors depends on their length, sequence, configuration and loading rate. Mechanistic insights gained from simulations analyses indicate that interpretation of experimental results should consider the influence of transient formation of secondary structure in peptide-based sensors and of overstretching in DNA-based sensors. These predictions can guide optimal fluorophore choice and facilitate the rational design of new sensors for use in protein, DNA, hybrid systems, and molecular devices.

Factors affecting behavioral intentions of farmers in Southeast Asia to technology adoption: A systematic review analysis.

Agriculture remains one of the most vital economic sectors in Southeast Asia. However, the progress of this sector has been hindered by small-scale production, limited technology application, decreasing agricultural land size and quality, climate change, rapid urbanization, low productivity, and aging farmers. Technology adoption by rural farmers is still lacking, and the factors affecting farmers' behavioral intentions are still unclear, especially in Southeast Asia. Therefore, this study aims to determine the factors affecting behavioral intentions toward technology adoption among rural Southeast Asian farmers. A systematic literature review was performed to determine the factors affecting behavioral attention to technology adoption among smallholder farmers in Southeast Asia. Approximately 18 related studies were found based on the systematic review. According to the results of the study, farmers' behavioral intentions toward technology adoption can be classified as internal factors or external factors. Internal factors explain behavior, while external factors explain household, institutional, technological, social, and economic factors. The review revealed 21 factors categorized into five subthemes: household-specific factors, institutional factors, economic factors, technology factors, and behavior factors. This study is important because agriculture remains one of the most vital and pillar economic sectors in Southeast Asia. In addition, it has become a guideline for determining farmers' behavioral intentions toward the adoption of new agricultural technology.

Cancer mortality among Colombian and foreign populations over a 15-year period.

Purpose: We aimed to compare cancer mortality among foreign- and Colombian populations in Colombia during the period of 2006-2020. Methods: This retrospective study utilized vital statistics from the Colombian National Department of Statistics (DANE). The dataset included variables such as age group, sex, country of permanent residency, insurance, education level, marital status, ethnicity, and cause of death. The population data to calculate rates was obtained from the Colombian census and the United Nations. Crude and adjusted rates as well as proportional mortality rates were calculated. Results: A total of 561,932 cancer deaths occurred in Colombia from 2006 to 2020. The foreign population (country of permanent residency different to Colombia) had a lower crude cancer mortality rate (31.1 per 100,000 inhabitants) than the Colombian population (81.9 per 100,000 inhabitants). However, the age-adjusted cancer mortality rate among the foreign population was 253.6 per 100,000, compared to 86.1 per 100,000 among the Colombian population. The proportional cancer mortality was 10.4 % among foreign population compared to 17.4 % among Colombian population. Conclusions: The proportional cancer mortality shows that the proportion of cancer-related deaths is greater among the Colombian population compared to the immigrant population. However, immigrants in Colombia have a higher age-adjusted cancer mortality rate than Colombians, indicating that immigrants have worse cancer outcomes than the Colombians even though the immigrant population is younger. This is likely due to the frequent barriers that immigrants encounter in accessing health care in Colombia. Future research needs to focus on access to care for the immigrant population by investigating cancer-related risk factors among immigrants and addressing their barriers to cancer prevention and treatment.

Does Severity of Chronic Urinary Retention as Estimated by Preoperative Residual Urine Estimation Negatively Impact the Outcome of Holmium Laser Enucleation of the Prostate?

OBJECTIVES: To evaluate the influence of preoperative post-void residual (PVR) volume on the outcomes of Holmium Laser Enucleation of the Prostate (HoLEP). Long term bladder obstruction can impair bladder contractility, which has been linked to failure to improve lower urinary tract symptoms (LUTS) after bladder outlet procedures. Elevated PVR constitutes a proxy for chronic retention and detrusor underactivity that can be non-invasively determined in office. METHODS: We evaluated men undergoing "en-bloc" HoLEP from July 2017 to August 2022 from our prospectively maintained database. PVR, prostate-specific antigen, International Prostate Symptom Score (IPSS) and uroflowmetry were assessed before surgery, at 3 months, 6 months and 1 year post- operatively. Patients' clinical characteristics and outcomes were compared according to preoperative PVR measurement by Group 1 (< 100 ml), Group 2 (101-300 ml), Group 3 (301-600 ml), and Group 4 (>600 ml). RESULTS: We included 318 men and found no significant differences between groups regarding clinical or perioperative characteristics including operative time, resected volume, catheter time and complications. Post-operative improvement in voiding parameters was found to be similar in all four groups up to one year of follow up. CONCLUSIONS: Severity of chronic urinary retention did not impact the outcomes of HoLEP, which provided great improvement in voiding parameters to men with LUTS secondary to benign prostatic hyperplasia, with no significant differences in outcomes between patient with preoperative PVR < 100 ml or > 600 ml. These findings should assist in reassuring patients with large bladder capacity that HoLEP can provide them with excellent functional voiding outcomes.

Stem cell transcriptional profiles from mouse subspecies reveal cis-regulatory evolution at translation genes.

A key goal of evolutionary genomics is to harness molecular data to draw inferences about selective forces that have acted on genomes. The field progresses in large part through the development of advanced molecular-evolution analysis methods. Here we explored the intersection between classical sequence-based tests for selection and an empirical expression-based approach, using stem cells from Mus musculus subspecies as a model. Using a test of directional, cis-regulatory evolution across genes in pathways, we discovered a unique program of induction of translation genes in stem cells of the Southeast Asian mouse M. m. castaneus relative to its sister taxa. We then mined population-genomic sequences to pursue underlying regulatory mechanisms for this expression divergence, finding robust evidence for alleles unique to M. m. castaneus at the upstream regions of the translation genes. We interpret our data under a model of changes in lineage-specific pressures across Mus musculus in stem cells with high translational capacity. Our findings underscore the rigor of integrating expression and sequence-based methods to generate hypotheses about evolutionary events from long ago.

Medical Imagery: Cytomegalovirus sialadenitis in a patient with B-cell acute lymphoblastic leukemia.

Cytomegalovirus (CMV) can cause a broad range of diseases, with severity depending on immune status, comorbidities, and age. Initial CMV infection usually occurs in childhood and is typically asymptomatic, leading to lifelong latency. In immunocompromised patients, CMV can affect multiple organs, but salivary gland infections are rare. This study presents a case of a 66-year-old woman with B-cell acute lymphoblastic leukemia who developed swelling and pain in the right preauricular region during pre-transplant consolidation therapy. Despite a recent bone marrow biopsy indicating morphological remission and a flow cytometry analysis detecting only 0.04 % B lymphoblasts, she exhibited these symptoms. A CT scan revealed enlargement, hyperdensity, and enhancement of the right parotid glands, with accompanying subcutaneous edema. A biopsy of the right parotid gland showed a dense interstitial lymphoplasmacytic infiltrate with numerous Cowdry bodies and smaller granular cytoplasmic inclusions, all testing positive for CMV immunohistochemistry. The findings confirm the diagnosis of CMV sialadenitis in an immunocompromised patient. This case underscores the importance of considering CMV infections in similar clinical scenarios, particularly in patients with compromised immune systems.

The emergence of cell-based protein arrays to test for polyspecific off-target binding of antibody therapeutics.

Specificity profiling is a requirement for monoclonal antibodies (mAbs) and antibody-directed biotherapeutics such as CAR-T cells prior to initiating human trials. However, traditional approaches to assess the specificity of mAbs, primarily tissue cross-reactivity studies, have been unreliable, leading to off-target binding going undetected. Here, we review the emergence of cell-based protein arrays as an alternative and improved assessment of mAb specificity. Cell-based protein arrays assess binding across the full human membrane proteome, ~6,000 membrane proteins each individually expressed in their native structural configuration within live or unfixed cells. Our own profiling indicates a surprisingly high off-target rate across the industry, with 33% of lead candidates displaying off-target binding. Moreover, about 20% of therapeutic mAbs in clinical development and currently on the market display off-target binding. Case studies and off-target rates at different phases of biotherapeutic drug approval suggest that off-target binding is likely a major cause of adverse events and drug attrition.

DNA damage and its association with early-life exposome: Gene-environment analysis in Colombian children under five years old.

Environmental exposures and gene-exposure interactions are the major causes of some diseases. Early-life exposome studies are needed to elucidate the role of environmental exposures and their complex interactions with biological mechanisms involved in childhood health. This study aimed to determine the contribution of early-life exposome to DNA damage and the modifying effect of genetic polymorphisms involved in air pollutants metabolism, antioxidant defense, and DNA repair. We conducted a cohort study in 416 Colombian children under five years. Blood samples at baseline were collected to measure DNA damage by the Comet assay and to determine GSTT1, GSTM1, CYP1A1, H2AX, OGG1, and SOD2 genetic polymorphisms. The exposome was estimated using geographic information systems, remote sensing, LUR models, and questionnaires. The association exposome-DNA damage was estimated using the Elastic Net linear regression with log link. Our results suggest that exposure to PM2.5 one year before the blood draw (BBD) (0.83, 95 %CI: 0.76; 0.91), soft drinks consumption (0.94, 0.89; 0.98), and GSTM1 null genotype (0.05, 0.01; 0.36) diminished the DNA damage, whereas exposure to PM2.5 one-week BBD (1.18, 1.06; 1.32), NO2 lag-5 days BBD (1.27, 1.18; 1.36), in-house cockroaches (1.10, 1.00; 1.21) at the recruitment, crowding at home (1.34, 1.08; 1.67) at the recruitment, cereal consumption (1.11, 1.04; 1.19) and H2AX (AG/GG vs. AA) (1.44, 1.11; 1.88) increased the DNA damage. The interactions between H2AX (AG/GG vs. AA) genotypes with crowding and PM2.5 one week BBD, GSTM1 (null vs. present) with humidity at the first year of life, and OGG1 (SC/CC vs. SS) with walkability at the first year of life were significant. The early-life exposome contributes to elucidating the effect of environmental exposures on DNA damage in Colombian children under five years old. The exposome-DNA damage effect appears to be modulated by genetic variants in DNA repair and antioxidant defense enzymes.

Detailed Phytochemical Composition, Cyto-/Hepatotoxicity, and Antioxidant/Anti-Inflammatory Profile of Moroccan Spices: A Study on Coriander, Caraway, and Mystical Cumin.

Coriander, caraway, and mystical cumin are famous for their aromatic properties and widely used in Moroccan cuisine. The nutritional/phytochemical composition of their seeds (used for food flavoring and preservation) were compared. Their antioxidant, anti-inflammatory, cytotoxic and hepatotoxic effects were also explored. The fat content was similar among the samples (13%), with monounsaturated fatty acids being predominant. The coriander and mystical cumin seeds were extremely rich in C18:1n9c (81 and 85%, respectively) while, in the caraway, C18:1n12 (25%) was found together with C18:1n9c (32%). The caraway seeds also presented a higher proportion of C18:2n6c (34%) than the other seeds (13 and 8%, correspondingly). γ-Tocotrienol was the major vitamin E form in all the samples. The caraway seeds contained double the amount of protein (~18%) compared to the other seeds (~8%) but, qualitatively, the amino acid profiles among all seeds were similar. The seeds were also rich in dietary fiber (40-53%); however, differences were found in their fiber profiles. Caraway showed the highest antioxidant profile and anti-inflammatory activity and an LC-DAD-ESI/MSn analysis revealed great differences in the phenolic profiles of the samples. Cytotoxicity (NCI-H460, AGS, MCF-7, and CaCo2) and hepatotoxicity (RAW 264.7) were not observed. In sum, besides their flavoring/preservation properties, these seeds are also relevant source of bioactive compounds with health-promoting activities.

Spontaneous Peritoneal Hemorrhage and Anemia: A Rare Case Report of Immune Thrombocytopenic Purpura.

Immune thrombocytopenia (ITP) is characterized by isolated thrombocytopenia manifesting with mucocutaneous bleeding symptoms, generally mild to moderate. The presence of severe symptoms or complications is rare but can be life-threatening and should be promptly diagnosed and treated. We present the case of a 14-year-old female presenting with abdominal tenderness and signs of peritoneal irritation and found to exhibit petechial rash in the buccal mucosa, scant petechiae, and superficial ecchymosis in both arms and legs on physical examination. Laboratory evaluation revealed severe thrombocytopenia and normocytic anemia. Abdominal ultrasound showed a significant peritoneal hematic effusion. The diagnosis of ITP with spontaneous peritoneal hemorrhage was made, and she was treated with intravenous immunoglobulin (IVIG) and antibiotic therapy, as well as one packed red blood cell transfusion because of worsened anemia on re-evaluation. A gradual rise in platelet count and hemoglobin was observed, as well as a gradual resolution of the peritoneal hemorrhage, with no further therapy.

Circulating platelets modulate oligodendrocyte progenitor cell differentiation during remyelination.

Revealing unknown cues that regulate oligodendrocyte progenitor cell (OPC) function in remyelination is important to optimise the development of regenerative therapies for multiple sclerosis (MS). Platelets are present in chronic non-remyelinated lesions of MS and an increase in circulating platelets has been described in experimental autoimmune encephalomyelitis (EAE) mice, an animal model for MS. However, the contribution of platelets to remyelination remains unexplored. Here we show platelet aggregation in proximity to OPCs in areas of experimental demyelination. Partial depletion of circulating platelets impaired OPC differentiation and remyelination, without altering blood-brain barrier stability and neuroinflammation. Transient exposure to platelets enhanced OPC differentiation in vitro, whereas sustained exposure suppressed this effect. In a mouse model of thrombocytosis (Calr+/-), there was a sustained increase in platelet aggregation together with a reduction of newly-generated oligodendrocytes following toxin-induced demyelination. These findings reveal a complex bimodal contribution of platelet to remyelination and provide insights into remyelination failure in MS.

Interpreting the role of antioxidants in vivo: A cautionary tale.

Bacteria have a remarkable ability to sense environmental stresses and to respond to these stressors by adapting their metabolism and physiology. In recent publications, investigators have suggested that multiple stresses that cause cell death share the mechanistic feature of stimulating the formation of reactive oxygen species (ROS). A central piece of evidence cited in these claims is the ability of exogenous antioxidant compounds to mitigate stress-related cell death. The validity of attributing a positive effect of exogenous antioxidants to ROS-mediated stress is challenged by an important study by Korshunov and Imlay in this issue of Molecular Microbiology. This study reports biochemical data that convincingly show that some commonly used antioxidants quench oxidants orders of magnitude too slowly to have a significant effect on the concentration of ROS in the cell. Under conditions where antioxidants minimize cell death, they also slow growth. Significantly, slowing cell growth by other means has the same restorative effect as adding an antioxidant. Based on the solid biochemical and genetic data, Korshunov and Imlay make the case for discarding the use of antioxidants to diagnose conditions that generate increased internal ROS production.