A Novel Protocol for the Early Detection of COVID-19 at a Skilled Nursing Facility.

Accurate measurement of vital signs are important at skilled nursing facilities (SNF). Recent technological advancements now enable automated vital sign measurements. This overcomes the limitations of traditional manual vital sign measurement, which is time-consuming and error-prone. We present a novel case where continuous vital sign measurement was used to detect meaningful vital sign changes that led to early detection of a COVID-19 outbreak at a SNF. Residents were continuously monitored for changes to baseline respiratory rate and heart rate and with a Probability of Change (POC). Variations in baseline respiratory rate and heart rate occurred in 66% and 42%, respectively, of COVID-19 positive individuals; 83% of participants had statistically significant variations in either vital sign. Clinical investigations are typically triggered by vital signs outside normal ranges. We present a novel methodology to detect subtle vital sign changes that can lead to earlier diagnosis, treatment, and recovery from infections, like COVID-19.

COVID-19 outbreak among temporary foreign workers in British Columbia, March to May 2020.

BACKGROUND: During the coronavirus disease 2019 (COVID-19) pandemic, temporary foreign workers (TFWs) provided a critical role to maintaining the food supply in Canada, yet workers faced a number of challenges that made them particularly vulnerable to COVID-19. The objective of this study was to describe the epidemiological investigation and public health response to a COVID-19 outbreak among TFWs in an agricultural setting in British Columbia from March to May 2020. METHODS: An outbreak was declared on March 28, 2020 following detection of two cases of COVID-19 among a group of 63 TFWs employed by a nursery and garden centre. Outbreak control measures included immediate isolation of cases, case finding via outreach screening and testing, cohorting of asymptomatic workers and enhanced cleaning and disinfection. The outbreak was declared over on May 10, 2020. RESULTS: A total of 26 COVID-19 cases were identified among the group of TFWs; no cases were identified among local workers. Cases were primarily male (77%) with a median age of 41 years. Symptom onsets ranged from March 8 to April 9, 2020. One case required overnight hospitalization for pneumonia. CONCLUSION: This was the first COVID-19 community outbreak identified in British Columbia and the first COVID-19 outbreak identified among TFWs in Canada. This outbreak began prior to implementation of provincial and federal quarantine orders for international travellers. A provincial policy was later developed that requires TFWs to quarantine in government-funded accommodation prior to deployment to agricultural settings.

Ezh2 Represses Transcription of Innate Lymphoid Genes in B Lymphocyte Progenitors and Maintains the B-2 Cell Fate.

Lymphocyte lineage specification and commitment requires the activation of lineage-specific genes and repression of alternative lineage genes, respectively. The mechanisms governing alternative lineage gene repression and commitment in lymphocytes are largely unknown. In this study, we demonstrate that Ezh2, which represses gene expression through methylation of histone 3 lysine 27, was essential for repression of numerous genes, including genes encoding innate lymphocyte transcription factors, specifically in murine B lymphocyte progenitors, but these cells maintained their B lymphocyte identity. However, adult Ezh2-deficient B lymphocytes expressed Lin28b, which encodes an RNA-binding protein associated with fetal hematopoietic gene expression programs, and these cells acquired a fetal B-1 lymphocyte phenotype in vitro and in vivo. Therefore, Ezh2 coordinates the repression of multiple gene programs in B lymphocytes and maintains the adult B-2 cell fate.

EZH2 Regulates the Developmental Timing of Effectors of the Pre-Antigen Receptor Checkpoints.

The histone methyltransferase EZH2 is required for B and T cell development; however, the molecular mechanisms underlying this requirement remain elusive. In a murine model of lymphoid-specific EZH2 deficiency we found that EZH2 was required for proper development of adaptive, but not innate, lymphoid cells. In adaptive lymphoid cells EZH2 prevented the premature expression of Cdkn2a and the consequent stabilization of p53, an effector of the pre-Ag receptor checkpoints. Deletion of Cdkn2a in EZH2-deficient lymphocytes prevented p53 stabilization, extended lymphocyte survival, and restored differentiation resulting in the generation of mature B and T lymphocytes. Our results uncover a crucial role for EZH2 in adaptive lymphocytes to control the developmental timing of effectors of the pre-Ag receptor checkpoints.

Identifying chelators for metalloprotein inhibitors using a fragment-based approach.

Fragment-based lead design (FBLD) has been used to identify new metal-binding groups for metalloenzyme inhibitors. When screened at 1 mM, a chelator fragment library (CFL-1.1) of 96 compounds produced hit rates ranging from 29% to 43% for five matrix metalloproteases (MMPs), 24% for anthrax lethal factor (LF), 49% for 5-lipoxygenase (5-LO), and 60% for tyrosinase (TY). The ligand efficiencies (LE) of the fragment hits are excellent, in the range of 0.4-0.8 kcal/mol. The MMP enzymes all generally elicit the same chelators as hits from CFL-1.1; however, the chelator fragments that inhibit structurally unrelated metalloenzymes (LF, 5-LO, TY) vary considerably. To develop more advanced hits, one hit from CFL-1.1, 8-hydroxyquinoline, was elaborated at four different positions around the ring system to generate new fragments. 8-Hydroxyquinoline fragments substituted at either the 5- or 7-positions gave potent hits against MMP-2, with IC(50) values in the low micromolar range. The 8-hydroxyquinoline represents a promising new chelator scaffold for the development of MMP inhibitors that was discovered by use of a metalloprotein-focused chelator fragment library.

Factor X and factor II activity levels do not always agree in warfarin-treated lupus anticoagulant patients.

Warfarin therapy is used in lupus anticoagulant patients with thrombosis and yet the prothrombin time (PT)/international normalized ratio (INR) in these patients can sometimes be falsely elevated. Both a PT-based factor II (FII) assay and a chromogenic, enzymatic factor X (CFX) assay have been used for monitoring when the INR may be artifactual. This study compared FII and CFX assays in lupus anticoagulant-positive and lupus anticoagulant-negative warfarin-treated patients in a cross-sectional study of samples from 21 lupus anticoagulant-positive and 19 lupus anticoagulant-negative outpatients. Plasma samples were simultaneously measured for FII and CFX and the ratio of FII/CFX was used to measure concordance. Compared with lupus anticoagulant-negative patients 14 of the 21 lupus anticoagulant-positive patients had lower FII/CFX ratios (P < 0.01). Three of the patients had ratios less than 0.6 indicating strong disagreement (P < 0.0001). The patient with the lowest FII/CFX ratio had evidence suggesting a specific antibody to FII. Another patient showed that the discordance between FII and CFX varied over time. The CFX assay in the laboratory was technically superior, more precise, and less costly. The CFX assay is preferred for warfarin therapy monitoring in lupus anticoagulant patients when INR artifacts are suspected.

Hydrogen-bond rigidified BODIPY dyes.

Boron difluoride adducts of diamidodipyrromethenes have been synthesized and characterized. The compounds represent a new group of the BODIPY family of fluorescent dyes. X-ray crystallography and solution (19)F NMR experiments show that a persistent hydrogen bond is formed between the boron-bound fluoride groups and the peripheral amide substituents. The modular synthesis of these compounds and their robust photophysical properties suggest that they may be useful compounds for materials and biological photochemical applications.

To bind zinc or not to bind zinc: an examination of innovative approaches to improved metalloproteinase inhibition.

This short review highlights some recent advances in matrix metalloproteinase inhibitor (MMPi) design and development. Three distinct approaches to improved MMP inhibition are discussed: (1) the identification and investigation of novel zinc-binding groups (ZBGs), (2) the study of non-zinc-binding MMPi, and (3) mechanism-based MMPi that form covalent adducts with the protein. Each of these strategies is discussed and their respective advantages and remaining challenges are highlighted. The studies discussed here bode well for the development of ever more selective, potent, and well-tolerated MMPi for treating several important disease pathologies.

Relationship between chromogenic factor X and international normalized ratio differs during early warfarin initiation compared with chronic warfarin administration.

Chromogenic factor X (CFX) monitoring is necessary in patients with potential international normalized ratio (INR) artifacts during warfarin therapy. The relationship of CFX with the INR needs to be quantitated to have warfarin protocols that are equivalent with either test as a monitoring parameter. This study investigated whether the CFX/INR relationship is different during warfarin initiation compared with that during chronic warfarin therapy. Outpatients (N = 164) taking chronic doses of warfarin and inpatients (N = 137) initiating warfarin therapy had plasma samples tested for CFX and INR. The best fit mathematical relationship of CFX and INR was determined for both groups. A six hundred and twenty-five bed, adult-only, private, tertiary care teaching hospital was the setting of the study. The best fit equation for chronic warfarin patients was quadratic using a reciprocal transformation of the INR. The best fit equation for the warfarin initiation patients was linear using logarithmic transformation of CFX and INR. The predicted CFX from INRs over the range of 1.4-2.2 was 7-18% higher in the warfarin initiation patients than in the chronic warfarin patients. Translation of CFX values into equivalent INRs for use in warfarin initiation and maintenance protocols is improved when using equations specific to the patient situation.

Effects of novel semiselective matrix metalloproteinase inhibitors on ex vivo cardiac structure-function.

The purpose of this study was to evaluate the ability of novel semiselective matrix metalloproteinase inhibitors (MMPI) to protect myocardial structure-function in the setting of ischemia-reperfusion injury. For this purpose, an isolated rat model of myocardial stunning and infarction was used. Isolated hearts were subjected to 20-30 minutes of global no-flow ischemia and 30-minute reperfusion. Myocardial performance was assessed as the product of the heart rate and left ventricular developed pressure (rate-pressure product, RPP). Coronary flow rates, ventricular weights, indicators of muscle (troponin I), and fibrillar collagen damage (collagen opalation) were measured. Four MMPI were tested: 2 non-hydroxamate, semiselective inhibitors (PY-2 and 1,2-HOPO-2) and 2 broad-spectrum inhibitors (PD166793 and CGS27023A). The non-hydroxamate, semiselective inhibitors were shown to be nontoxic in cocultures of cardiac cells. Results indicate that semiselective inhibitors (in particular 1,2-HOPO-2) yield improved cardiac performance (approximately 23% higher RPP vs. controls) and coronary flow rates (approximately 22%), reducing muscle (approximately 25%) and fibrillar collagen damage (approximately 60%). Evidence suggests the involvement of matrix metalloproteinase-2 in these actions. Interestingly, broad-spectrum inhibitors only show modest improvement (approximately 8% higher RPP vs. controls) without affecting the other measured parameters. In conclusion, semiselective MMPI can act as cardioprotectors in isolated perfused rat hearts. Protection is observed in all structural components of the myocardium translating into improved contractile function. Based on these findings, non-hydroxamate, semiselective MMPI warrant further studies as to their ability to protect ischemic myocardium in the in vivo setting.

Thioamide hydroxypyrothiones supersede amide hydroxypyrothiones in potency against anthrax lethal factor.

Anthrax lethal factor (LF) is a critical virulence factor in the pathogenesis of anthrax. A structure-activity relationship (SAR) of potential lethal factor inhibitors (LFi) is presented in which the zinc-binding group (ZBG), linker, and backbone moieties for a series of hydroxypyrone-based compounds were systematically varied. It was found that hydroxypyrothione ZBGs generate more potent inhibitors than hydroxypyrone ZBGs. Furthermore, coupling the hydroxypyrothione to a backbone group via a thioamide bond improves potency when compared to an amide linker. QM/MM studies show that the thioamide bond in these inhibitors allows for the formation of two additional hydrogen bonds with the protein active site. In both types of hydroxypyrothione compounds, ligand efficiencies of 0.29-0.54 kcal mol(-1) per heavy atom were achieved. The results highlight the need for a better understanding to optimize the interplay between the ZBG, linker, and backbone to get improved LFi.

Zinc-binding groups modulate selective inhibition of MMPs.

The need for selective matrix metalloproteinase (MMP) inhibition is of interest because of the range of pathologies mediated by different MMP isoforms. The development of more selective MMP inhibitors (MMPi) may help to overcome some of the undesired side effects that have hindered the clinical success of these compounds. In an effort to devise new approaches to selective inhibitors, herein we describe several novel MMPi and show that their selectivity is dependent on the nature of the zinc-binding group (ZBG). This is in contrast to most current MMPi, which obtain isoform selectivity solely from the peptidomimetic backbone portion of the compound. In the present study, six different hydroxypyrone and hydroxypyridinone ZBGs were appended to a common biphenyl backbone and the inhibition efficiency of each inhibitor was determined in vitro (IC(50) values) against MMP-1, -2, -3, -7, -8, -9, -12, and -13. The results show that the selectivity profile of each inhibitor is different as a result of the various ZBGs. Computational modeling studies were used to explain some trends in the observed selectivity profiles. To assess the importance of the ZBG in a biological model, two of the semiselective, potent MMPi (and one control) were evaluated using an isolated perfused rat heart system. Hearts were subjected to ischemia reperfusion injury, and recovery of contractile function was examined. In this model, only one of the two MMPi showed significant and sustained heart recovery, demonstrating that the choice of ZBG can have a significant effect in a relevant pathophysiological endpoint.

Experimental evaluation and thermo-physical analysis of thermogenesis in male and female cycad cones.

Thermogenically elevated cone temperatures were measured in two Macrozamia cycad species that differ in their daily heating time. Mathematical models of the cones' thermo-physics were tested for their accuracy in predicting these cone temperatures and for comparison of the energetics of both species and the sexes within species. These models accurately predicted temperatures over approximately 8-h periods with average errors of: 0.46 degrees C for Macrozamia lucida, pollinated by the thrips, Cycadothrips chadwicki, that moves during mid-day concurrent with cone heating; and 0.38 degrees C for Macrozamia machinii, pollinated by the weevil, Tranes sp., that moves after sunset during cone heating. The combination of models and experiments revealed a thermogenic sexual dimorphism in both species. For M. lucida, the estimated female mass specific metabolisms, and their theoretically possible and actual temperature increases due to thermogenic metabolism were only 57, 67, and 76% of males. In addition, female thermogenic metabolisms began and peaked much earlier and lasted significantly longer than males (all differences >1 h), and female metabolic peaks preceded their temperature peaks by 65 vs. 46 min for males. The timing of almost all male cone metabolic peaks was optimized with respect to the diurnal ambient heating cycle so that cone temperatures achieved a maximum temperature gain, whereas most female metabolic peaks occurred much earlier than optimal. In M. machinii, thermogenic sexual dimorphism is much larger since its male peak metabolisms are larger, and its females' peaks are much smaller compared to those of M. lucida. This study provides new information regarding the energetics of cycad cones that is relevant to understanding the interactions of the plant traits with their obligate pollinators' behavior.