Remodeling of colon plasma cell repertoire within ulcerative colitis patients

Plasma cells (PCs) constitute a significant fraction of colonic mucosal cells and contribute to inflammatory infiltrates in ulcerative colitis (UC). While gut PCs secrete bacteria-targeting IgA antibodies, their role in UC pathogenesis is unknown. We performed single-cell V(D)J- and RNA-seq on sorted B cells from the colon of healthy individuals and patients with UC. A large fraction of B cell clones is shared between different colon regions, but inflammation in UC broadly disrupts this landscape, causing transcriptomic changes characterized by an increase in the unfolded protein response (UPR) and antigen presentation genes, clonal expansion, and isotype skewing from IgA1 and IgA2 to IgG1. We also directly expressed and assessed the specificity of 152 mAbs from expanded PC clones. These mAbs show low polyreactivity and autoreactivity and instead target both shared bacterial antigens and specific bacterial strains. Altogether, our results characterize the microbiome-specific colon PC response and how its disruption might contribute to inflammation in UC.

B cell genomics behind cross-neutralization of SARS-CoV-2 variants and SARS-CoV

Monoclonal antibodies (mAbs) are a focus in vaccine and therapeutic design to counteract severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its variants. Here, we combined B cell sorting with single-cell VDJ and RNA sequencing (RNA-seq) and mAb structures to characterize B cell responses against SARS-CoV-2. We show that the SARS-CoV-2-specific B cell repertoire consists of transcriptionally distinct B cell populations with cells producing potently neutralizing antibodies (nAbs) localized in two clusters that resemble memory and activated B cells. Cryo-electron microscopy structures of selected nAbs from these two clusters complexed with SARS-CoV-2 spike trimers show recognition of various receptor-binding domain (RBD) epitopes. One of these mAbs, BG10-19, locks the spike trimer in a closed conformation to potently neutralize SARS-CoV-2, the recently arising mutants B.1.1.7 and B.1.351, and SARS-CoV and cross-reacts with heterologous RBDs. Together, our results characterize transcriptional differences among SARS-CoV-2-specific B cells and uncover cross-neutralizing Ab targets that will inform immunogen and therapeutic design against coronaviruses.

The Fire and Smoke Model Evaluation Experiment-A Plan for Integrated, Large Fire-Atmosphere Field Campaigns

The Fire and Smoke Model Evaluation Experiment (FASMEE) is designed to collect integrated observations from large wildland fires and provide evaluation datasets for new models and operational systems. Wildland fire, smoke dispersion, and atmospheric chemistry models have become more sophisticated, and next-generation operational models will require evaluation datasets that are coordinated and comprehensive for their evaluation and advancement. Integrated measurements are required, including ground-based observations of fuels and fire behavior, estimates of fire-emitted heat and emissions fluxes, and observations of near-source micrometeorology, plume properties, smoke dispersion, and atmospheric chemistry. To address these requirements the FASMEE campaign design includes a study plan to guide the suite of required measurements in forested sites representative of many prescribed burning programs in the southeastern United States and increasingly common high-intensity fires in the western United States. Here we provide an overview of the proposed experiment and recommendations for key measurements. The FASMEE study provides a template for additional large-scale experimental campaigns to advance fire science and operational fire and smoke models.

Fire behavior and smoke modeling: Model improvement and measurement needs for next-generation smoke research and forecasting systems

There is an urgent need for next-generation smoke research and forecasting (SRF) systems to meet the challenges of the growing air quality, health, and safety concerns associated with wildland fire emissions. This review paper presents simulations and experiments of hypothetical prescribed burns with a suite of selected fire behavior and smoke models and identifies major issues for model improvement and the most critical observational needs. The results are used to understand the new and improved capability required for the next-generation SRF systems and to support the design of the Fire and Smoke Model Evaluation Experiment (FASMEE) and other field campaigns. The next-generation SRF systems should have more coupling of fire, smoke, and atmospheric processes to better simulate and forecast vertical smoke distributions and multiple sub-plumes, dynamical and high-resolution fire processes, and local and regional smoke chemistry during day and night. The development of the coupling capability requires comprehensive and spatially and temporally integrated measurements across the various disciplines to characterize flame and energy structure (e.g., individual cells, vertical heat profile and the height of well mixing flaming gases), smoke structure (vertical distributions and multiple sub-plumes), ambient air processes (smoke eddy, entrainment and radiative effects of smoke aerosols), fire emissions (for different fuel types and combustion conditions from flaming to residual smoldering), as well as night-time processes (smoke drainage and super-fog formation).

Audit of Pulse Oximetry Screening for Critical Congenital Heart Disease (Cchd) in Newborns

BACKGROUND: UK data suggests that 25% of infants with CCHD are not diagnosed with heart disease until after discharge from the nursery (0.6 per 1000). In general SpO2 ≤ to 95% or a difference of upper and lower SpO2 of more than 3% in a newborn greater than 24 hours of age is considered significant. In March 2014 the Maternal Child Newborn Screening Committee of the Provincial Council for Maternal Child Health (PCMCH) recommended screening for critical congenital heart disease in Ontario.

OBJECTIVES: To assess the efficacy and cost related parameters of a new screening protocol for CCHD.

DESIGN/METHODS: An audit of consecutive healthy normal newborn patients over a one-year period was undertaken.

RESULTS: The cost of screening estimated for our center was approximately $7.20 per patient. The median age of screening was 25 hours (6-80 hours). Four patients were screened positive and were seen by a paediatrician in consultation. No Echocardiograms were ordered. No child in this screening survey had CCHD (specificity 99.4%). The screening compliance was 94.7%. One patient from our regional catchment area was delivered at an alternate secondary level center where there is no CCHD protocol in effect. The infant was discharged home and returned to the primary level center two days later in shock. The ultimate diagnosis was Hypoplastic Left Heart Syndrome. The estimated cost of the resuscitation was $1000. The emergency transport (direct) cost for this unstable newborn by helicopter is estimated to be $5000.00.

Conclusion: Cost analysis: The total direct costs of the CCHD screening program for a year is approximately $5200. The costs for the four patients who were falsely identified as having CCHD is estimated at $200. The total direct cost to the system of the one patient in our region who was not screened and was subsequently identified as having CCHD was estimated to be $6000. Assessment issues: In contrast to the US references, none of the false positive cases had an echocardiogram ordered. The cases were dealt with by utilizing a consultation with a paediatrician. Compliance with routine newborn orders: The screening compliance rate of 94.7%.

CONCLUSIONS: A simple screening test for Critical Congenital Heart Disease was successfully undertaken in a secondary level center over a one-year period. The test was cost effective, with high specificity (99.4%) and good compliance (94.7%).

Transient exacerbation of tuberculous lymphadenitis during chemotherapy in patients with AIDS

We describe three men with disseminated, drug-sensitive tuberculosis and advanced human immunodeficiency virus disease (CD4+ lymphocyte count, < 50/mm3) who had flares of tuberculous lymphadenitis with suppuration during the initial weeks of successful chemotherapy. Bactericidal drugs may kindle these transient exacerbations, which involve neutrophils but apparently do not require normal helper T cell function. In patients with AIDS, as in immunocompetent individuals, treatment-related flares of lymphadenitis are usually not an adverse sign, provided that drug resistance and nonadherence have been excluded.

Histamine blockade and cardiovascular changes following heparin administration during cardiac surgery

Large doses of heparin given as a bolus may produce hypotension; however, conflicting reports exist about the mechanisms involved. This study was undertaken to determine the role of histamine in beef lung heparin-induced hypotension and the efficacy of histamine-receptor blockade in attenuating this undesirable side effect in patients undergoing cardiac surgery. Two hundred patients with good ventricular function were studied after they were randomized into four equal groups. Group I (control) received no histamine-receptor blockade, group II received 1 mg/kg of diphenhydramine 30 minutes prior to heparin administration, group III received 5 mg/kg of cimetidine 4 hours and again 30 minutes before heparin administration, and group IV received 1 mg/kg of diphenhydramine 30 minutes prior to heparin administration and 5 mg/kg of cimetidine 4 hours and 30 minutes before heparin administration. Hemodynamic variables, plasma histamine, and ionized calcium levels were measured before and after heparin administration. Significant hypotension occurred in group I patients after heparin administration. Mean arterial pressure decreased from 95 +/- 5 to 67 +/- 1.5 mm Hg (P less than 0.005) after 1 minute and to 85 +/- 2 mm Hg (P less than 0.05) at 4 minutes. Those changes were significantly greater than in group II (P less than 0.025) and Group IV (P less than 0.005) patients, in whom no significant hypotension was found. In group III, mean arterial pressure decreased from 92 +/- 3 to 75 +/- 1 mm Hg (P less than 0.05) after 1 minute and returned toward baseline values after 4 minutes. Histamine levels increased significantly in all groups of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of a hot dry climate on the haemorrheology of healthy males and patients with acute myocardial infarction

We studied the influence of an extremely hot dry summer and temperate winter on the haemorrheology of 82 healthy males (controls) and 101 male patients with acute myocardial infarction (AMI). The haematocrit (Hct), blood viscosity (B1V) and Hct/B1V ratio were measured in these subjects working 'outdoors' and in an air-conditioned environment ('indoors'). The 'summer outdoor' controls had a higher B1V and a lower Hct/B1V when compared to the 'winter outdoor' controls (P less than 0.01), and the 'summer indoor' controls had a lower Hct and Hct/B1V when compared to the 'winter indoor' control group (P less than 0.02). The haemorrheology of 'winter indoor' AMI patients was not different from the controls, except for the Hct/B1V. The 'summer indoor' group had a higher Hct (P less than 0.05) and B1V (P less than 0.001) and a lower Hct/B1V (P less than 0.02) when compared to the controls. 'Summer outdoor' AMI patients had the most abnormal haemorrheology of all groups. AMI patients with Hct/B1V less than 7 had a significantly higher prevalence of hypotension and shock syndrome compared to those whose Hct/B1V was greater than or equal to 7 (P less than 0.05). We conclude that in healthy males, there was a seasonal difference in haemorrheology which was due to acclimatization to heat. During summer, AMI patients working outdoors had the most abnormal haemorrheology on admission and the occurrence of complications was also higher in them. We believe that these abnormalities resulted due to inadequate adjustments to heat.

Seasonal variation in the incidence of unstable angina and acute myocardial infarction: effect of dry hot climate on the occurrence of complications following acute myocardial infarction

The incidence of unstable angina (UA) and acute myocardial infarction (AMI), and the occurrence of complications following AMI were studied retrospectively by utilizing data of 7859 patients admitted during three consecutive winter and summer periods from 1979 to 1982. In all patients, UA was more frequent during summer than in winter: 58 out of 3819 (1.5%) versus 37 out of 4040 (0.9%) respectively (P less than 0.05). A similar difference was observed for the incidence of AMI: 183 out of 3819 (4.8%) in summer versus 157 out of 4040 (3.9%) in winter (P less than 0.05). This seasonal variation in the incidence of UA and AMI was significant only in male patients (P less than 0.05). Shock and mortality were higher during summer than in winter in all, and in male AMI patients with or without previous infarction. It is suggested that a hot dry summer is an important risk factor for the occurrence of UA and AMI, and the associated serious complications following the latter in males.

Left ventricular thrombosis, wall motion abnormalities, and blood viscosity changes after first transmural anterior myocardial infarction

Sixty-three consecutive patients with a first transmural anterior myocardial infarction (MI) were studied by serial two-dimensional echocardiography (2D echo) to relate left ventricular (LV) thrombosis with serial changes in blood and plasma viscosity and fibrinogen levels, and wall motion abnormalities at the thrombus site, in order to identify those prone to this complication. The results suggest that an early 2D echo be performed in all patients with acute transmural anterior MI to detect LV thrombi and to identify those at risk of thrombosis.