Possible Effects of Air Temperature on COVID-19 Disease Severity and Transmission Rates

Currently available data are consistent with increased severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication at temperatures encountered in the upper airways (25–33°C when breathing room temperature air, 25°C) compared to those in the lower airways (37°C). One factor that may contribute to more rapid viral growth in the upper airways is the exponential increase in SARS-CoV-2 stability that occurs with reductions in temperature, as measured in vitro. Because SARS-CoV-2 frequently initiates infection in the upper airways before spreading through the body, increased upper airway viral growth early in the disease course may result in more rapid progression of disease and potentially contribute to more severe outcomes. Similarly, higher SARS-CoV-2 viral titer in the upper airways likely supports more efficient transmission. Conversely, the possible significance of air temperature to upper airway viral growth suggests that prolonged delivery of heated air might represent a preventative measure and prophylactic treatment for coronavirus disease 2019.

IMF deal may aid economic stabilisation in Suriname

Significance This is positive news for the country, which experienced a sharp economic decline in 2020 and had been struggling to bolster economic activity for several years before that. New President Chandrikapersad Santokhi will hope that the IMF deal gives his administration some breathing room to enact unpopular economic measures. Impacts Ongoing discussions with China could lead to supplementary aid and financing from Beijing. Increased fiscal support will encourage greater investment, especially into the oil sector. Greater economic cooperation with Guyana on oil projects will boost the sector's outlook.

Rapid Clinical and Radiological Improvement in a Patient with Severe COVID-19 Infection Treated with Convalescent Plasma

The COVID-19 pandemic has affected more than 100 million people worldwide. One of the major presentations is pneumonia. Patients are classified as severe when they have an arterial oxygen saturation of less than 94% on breathing room air. We present a case of a healthy 29-year-old man who had severe COVID-19 pneumonia and responded dramatically to two doses of convalescent plasma. This case underlines the importance of administering the plasma in the first few days of the disease.

TrkB Signaling Contributes to Transdiaphragmatic Pressure Generation in Aged Mice

Ventilatory deficits are common in old age and may result from neuromuscular dysfunction. Signaling via the tropomyosin-related kinase receptor B (TrkB) regulates neuromuscular transmission and in young mice is important for the generation of transdiaphragmatic pressure (Pdi). Loss of TrkB signaling worsened neuromuscular transmission failure and reduced maximal Pdi, and these effects are similar to those observed in old age. Administration of TrkB agonists such as 7,8-dihydroxyflavone (7,8-DHF) improves neuromuscular transmission in young and old mice (18 months; 75% survival). We hypothesized that TrkB signaling contributes to Pdi generation in old mice, particularly during maximal force behaviors. Old male and female TrkBF616A mice, with a mutation that induces 1NMPP1-mediated TrkB kinase inhibition, were randomly assigned to systemic treatment with vehicle, 7,8-DHF, or 1NMPP1 one hour prior to experiments. Pdi was measured during eupneic breathing (room air), hypoxia-hypercapnia (10% O2/5% CO2), tracheal occlusion, spontaneous deep breaths ("sighs"), and bilateral phrenic nerve stimulation (Pdimax). There were no differences in the Pdi amplitude across treatments during ventilatory behaviors (eupnea, hypoxia-hypercapnia, occlusion or sigh). As expected, Pdi increased from eupnea and hypoxia-hypercapnia (~7 cm H2O) to occlusion and sighs (~25 cm H2O), with no differences across treatments. Pdimax was ~50 cm H2O in the vehicle and 7,8-DHF groups and ~40 cm H2O in the 1NMPP1 group (F8,74 = 2; p = 0.02). Our results indicate that TrkB signaling is necessary for generating maximal forces by the diaphragm muscle in old mice, and are consistent with aging effects of TrkB signaling on neuromuscular transmission.

Dexmedetomidine-Tiletamine-Zolazepam Followed by Inhalant Anesthesia in Spectacled Bears (Tremarctos ornatus)

Background: The spectacled bear (Tremarctos ornatus) is the only bear species inhabiting South America and is classified as vulnerable according to the International Union for Conservation of Nature (IUCN) Red List. Among the few publications on the use of general anesthesia and advanced monitoring of ursids in veterinary hospital settings, little is described regarding chemical restraint, general anesthesia and monitoring of spectacled bears. This case series describes the use of a dexmedetomidine-tiletamine-zolazepam chemical restraint combination and its effects on cardiorespiratory variables and arterial blood gases observed in two spectacled bears submitted to isoflurane anesthesia for imaging and/or surgical procedures.Cases: Two female, one adult and one senile, all-term captive spectacled bears were referred to the Veterinary Medical Teaching Hospital at the Universidade Estadual Paulista - Unesp, Botucatu campus, both with a presumable history of recent trauma. After immobilization with an intramuscular (IM) administration of tiletamine-zolazepam (3.8 - 4.3 mg/kg) and dexmedetomidine (6.4 - 7.6 µg/kg), anesthesia induction was achieved by means of intravenous (IV) propofol (1 - 2 mg/kg). The patients then underwent isoflurane inhalant anesthesia and were submitted to intermittent positive-pressure ventilation through the remainder of the procedures. Initial settings of inspiratory flow rate were adjusted to obtain Ppeak of 10 cmH2O and tidal volumes (Vt) of 10 mL/kg, as well as respiratory rates (ƒR)and inspiration-to-expiration (I:E) ratio of 10 breaths/min and 1:2, respectively, and were then adjusted throughout anesthesia to maintain normocapnia (end-tidal carbon dioxide concentrations between35 and 45 mmHg). One of the individuals was chemically restrained (6.4 mg/kg of tiletamine-zolazepam and 7.7 µg/kg of dexmedetomidine) on a second anesthetic event for imaging procedures. Arterial blood gas analysis were performed with the subjects breathing room air and oxygen-enriched air. Both animals exhibited severe hypoxemia (partial pressure of oxygen [PaO2] < 60 mmHg) while breathing room air (inspired oxygen fraction [FiO2] ≅ 0.21). An impaired blood oxygenation (PaO2/FiO2 < 400) was still observed despite mechanical ventilation and the provision of 1.0 FiO2. Alveolar recruitment maneuvers (3 sequential mechanical sights with peak airway pressure at 20 - 30 cmH2O during 15 - 30 s each) were then performed, which resulted in improved PaO2/FiO2 ratios. All other blood gas, electrolytes and acid-base variables did not appear to be importantly altered by chemical restraint and general anesthesia.Discussion: Dexmedetomidine-tiletamine-zolazepam resulted in reliable chemical restraints and is a feasible option for immobilizing spectacled bears, though severe hypoxemia may proceed. Hypoxemia is the most commonly described complication in bear anesthesia, and was also evidenced in the current report. However, low PaO2/FiO2 ratios tend to be accompanied by hypercapnia and therefore counteracted by oxygen supplementation in bears, which was not observed in the present report. In fact, blood oxygenation only reached regular values after alveolar recruitment maneuvers, which is compatible to an atelectasis-related hypoxemia. Therefore, either inhalant anesthesia or field chemical restraint should be accompanied by advanced monitoring (cardiorespiratory variables and blood gas analysis) in until further studies address the management of hypoxemia in spectacled bear. since Advanced monitoring was of major importance for a safe outcome and an uneventful recovery in this species.Keywords: balanced anesthesia, dexmedetomidine, general anesthesia, spectacled bear, Tremarctos ornatus, wildlife.

Engaging the Evil Empire

In a narrative-redefining approach, this book dramatically alters how we look at the beginning of the end of the Cold War. Tracking key events in US–Soviet relations across the years between 1980 and 1985, the book shows that covert engagement gave way to overt conversation as both superpowers determined that open diplomacy was the best means of furthering their own, primarily competitive, goals. The book details the history of these dramatic years, as President Ronald Reagan consistently applied a disciplined carrot-and-stick approach, reaching out to Moscow while at the same time excoriating the Soviet system and building up US military capabilities. The received wisdom in diplomatic circles is that the beginning of the end of the Cold War came from changing policy preferences and that President Reagan, in particular, opted for a more conciliatory and less bellicose diplomatic approach. In reality, the book demonstrates, Reagan and ranking officials in the National Security Council had determined that the United States enjoyed a strategic margin of error that permitted it to engage Moscow overtly. As US grand strategy developed, so did that of the Soviet Union. This book covers five critical years of Cold War history when Soviet leaders tried to reduce tensions between the two nations in order to gain economic breathing room and, to ensure domestic political stability, prioritize expenditures on butter over those on guns. The book shifts the focus of Cold War historians away from exclusive attention on Washington by focusing on the years of back-channel communiqués and internal strategy debates in Moscow as well as Prague and East Berlin.

Minimizing airflow turbulence in women lowers the work of breathing to levels similar to men

When healthy young women breathe heliox gas during exercise, their work of breathing is not different from men breathing room air. Heliox inspiration reduces airway resistance and promotes laminar flow, which is a physiologically similar effect of increasing airway size. Our findings provide experimental evidence that smaller airways in women are responsible for the greater work of breathing during exercise.

Absence of dynamic hyperinflation during exhaustive exercise in severe COPD reflects submaximal IC maneuvers rather than a nonhyperinflator phenotype

Approximately 20% of chronic obstructive pulmonary disease (COPD) patients have been considered to have a “nonhyperinflator phenotype.” However, this judgment depends on patients making a fully maximal inspiratory capacity (IC) maneuver at rest, since the IC during exercise is compared with this baseline measurement. We hypothesized that IC maneuvers at rest are sometimes submaximal and tested this hypothesis by measuring IC and associated neural respiratory drive at rest and during inhalation of CO2 and exercise in patients with COPD. Twenty-six COPD patients [age 66 ± 6 yr, mean forced expiratory volume in 1 s (FEV1) 40 ± 11% predicted] and 39 healthy subjects (age 39 ± 14 yr, FEV1 98 ± 12% predicted) were studied. IC and the diaphragm electromyogram (EMGdi) associated with it (EMGdi-IC) and forced inspiratory vital capacity (FIVC) and its corresponding EMGdi (EMGdi-FIVC) were measured during inhalation of 8% CO2 (8% CO2-92% O2) and room air. Incremental exhaustive cycle ergometer exercise was also performed in both patients with COPD and healthy subjects. IC, EMGdi-IC, FIVC, and EMGdi-FIVC during breathing 8% CO2 were significantly greater than those during breathing room air in both patients with COPD and healthy subjects (all P < 0.001). EMGdi-IC in patients with COPD constantly increased during exercise from 145 ± 40 µV at rest to 185 ± 52 µV at the end of exercise but change in IC was variable. Neural respiratory drive and its relevant IC increased during hypercapnia. Exercise-related hypercapnia in patients with COPD raises neural respiratory drives, which compensate for IC reduction, leading to underestimation of dynamic hyperinflation measured by IC at rest breathing room air. NEW & NOTEWORTHY Inspiratory capacity measured during hypercapnia is higher than that during eucapnia. Thus total lung capacity is not always be achieved by a standard inspiratory capacity maneuver, leading to risk of underestimation of dynamic hyperinflation in patients with severe chronic obstructive pulmonary disease after exhaustive exercise.