Apolipoprotein E controls Dectin-1-dependent development of monocyte-derived alveolar macrophages upon pulmonary ß-glucan-induced inflammatory adaptation.

The lung is constantly exposed to the outside world and optimal adaptation of immune responses is crucial for efficient pathogen clearance. However, mechanisms that lead to lung-associated macrophages' functional and developmental adaptation remain elusive. To reveal such mechanisms, we developed a reductionist model of environmental intranasal ß-glucan exposure, allowing for the detailed interrogation of molecular mechanisms of pulmonary macrophage adaptation. Employing single-cell transcriptomics, high-dimensional imaging and flow cytometric characterization paired with in vivo and ex vivo challenge models, we reveal that pulmonary low-grade inflammation results in the development of apolipoprotein E (ApoE)-dependent monocyte-derived alveolar macrophages (ApoE+CD11b+ AMs). ApoE+CD11b+ AMs expressed high levels of CD11b, ApoE, Gpnmb and Ccl6, were glycolytic, highly phagocytic and produced large amounts of interleukin-6 upon restimulation. Functional differences were cell intrinsic, and myeloid cell-specific ApoE ablation inhibited Ly6c+ monocyte to ApoE+CD11b+ AM differentiation dependent on macrophage colony-stimulating factor secretion, promoting ApoE+CD11b+ AM cell death and thus impeding ApoE+CD11b+ AM maintenance. In vivo, ß-glucan-elicited ApoE+CD11b+ AMs limited the bacterial burden of Legionella pneumophilia after infection and improved the disease outcome in vivo and ex vivo in a murine lung fibrosis model. Collectively these data identify ApoE+CD11b+ AMs generated upon environmental cues, under the control of ApoE signaling, as an essential determinant for lung adaptation enhancing tissue resilience.

Multistate outbreaks of Salmonella infections linked to imported Maradol papayas - United States, December 2016-September 2017.

Foodborne salmonellosis causes approximately 1 million illnesses annually in the United States. In the summer of 2017, we investigated four multistate outbreaks of Salmonella infections associated with Maradol papayas imported from four Mexican farms. PulseNet initially identified a cluster of Salmonella Kiambu infections in June 2017, and early interviews identified papayas as an exposure of interest. Investigators from Maryland, Virginia and Food and Drug Administration (FDA) collected papayas for testing. Several strains of Salmonella were isolated from papayas sourced from Mexican Farm A, including Salmonella Agona, Gaminara, Kiambu, Thompson and Senftenberg. Traceback from two points of service associated with illness sub-clusters in two states identified Farm A as a common source of papayas, and three voluntary recalls of Farm A papayas were issued. FDA sampling isolated four additional Salmonella strains from papayas sourced from Mexican Farms B, C and D. In total, four outbreaks were identified, resulting in 244 cases with illness onset dates from 20 December 2016 to 20 September 2017. The sampling of papayas and the collaborative work of investigative partners were instrumental in identifying the source of these outbreaks and preventing additional illnesses. Evaluating epidemiological, laboratory and traceback evidence together during investigations is critical to solving and stopping outbreaks.

Home interventions are effective at decreasing indoor nitrogen dioxide concentrations.

UNLABELLED: Nitrogen dioxide (NO2 ), a by-product of combustion produced by indoor gas appliances such as cooking stoves, is associated with respiratory symptoms in those with obstructive airways disease. We conducted a three-armed randomized trial to evaluate the efficacy of interventions aimed at reducing indoor NO2 concentrations in homes with unvented gas stoves: (i) replacement of existing gas stove with electric stove; (ii) installation of ventilation hood over existing gas stove; and (iii) placement of air purifiers with high-efficiency particulate air (HEPA) and carbon filters. Home inspection and NO2 monitoring were conducted at 1 week pre-intervention and at 1 week and 3 months post-intervention. Stove replacement resulted in a 51% and 42% decrease in median NO2 concentration at 3 months of follow-up in the kitchen and bedroom, respectively (P = 0.01, P = 0.01); air purifier placement resulted in an immediate decrease in median NO2 concentration in the kitchen (27%, P < 0.01) and bedroom (22%, P = 0.02), but at 3 months, a significant reduction was seen only in the kitchen (20%, P = 0.05). NO2 concentrations in the kitchen and bedroom did not significantly change following ventilation hood installation. Replacing unvented gas stoves with electric stoves or placement of air purifiers with HEPA and carbon filters can decrease indoor NO2 concentrations in urban homes. PRACTICAL IMPLICATIONS: Several combustion sources unique to the residential indoor environment, including gas stoves, produce nitrogen dioxide (NO2), and higher NO2 concentrations, are associated with worse respiratory morbidity in people with obstructive lung disease. A handful of studies have modified the indoor environment by replacing unvented gas heaters; this study, to our knowledge, is the first randomized study to target unvented gas stoves. The results of this study show that simple home interventions, including replacement of an unvented gas stove with an electric stove or placement of HEPA air purifiers with carbon filters, can significantly decrease indoor NO2 concentrations.

Randomized controlled trial comparing the McGrath videolaryngoscope with the C-MAC videolaryngoscope in intubating adult patients with potential difficult airways.

BACKGROUND: Difficult and failed intubations, although rarely encountered, are major causes of morbidity and mortality in the current anaesthetic practice. To reduce the incidence of difficult and failed intubations, several devices including the recently developed videolaryngoscopes are available. This randomized controlled study aims to compare the use of the McGrath videolaryngoscope with the C-MAC videolaryngoscope in adult patients with potential difficult airways. METHODS: A total of 130 patients with the Mallampati grade of ≥3, requiring orotracheal intubation, were randomized to either having intubation with the McGrath videolaryngoscope or the C-MAC videolaryngoscope. The primary outcome was time to intubation. The laryngoscopic view, the number of intubation attempts, the proportion of intubation success, the ease of intubation, the haemodynamic responses to intubation, and the incidence of any complications were also recorded. RESULTS: Time to successful intubation with the C-MAC videolaryngoscope was shorter when compared with the McGrath videolaryngoscope {50 s [inter-quartile range (IQR) 38-70] vs 67 s (IQR 49-108), P<0.001}, despite the McGrath videolaryngoscope providing significantly more grade 1 laryngoscopic views. The C-MAC videolaryngoscope also resulted in significantly fewer intubation attempts and greater ease of intubation when compared with the McGrath videolaryngoscope. There were no statistically significant differences in the proportion of intubation success, the number of complications, and the changes in haemodynamic responses between the two videolaryngoscopes. CONCLUSIONS: The C-MAC videolaryngoscope allowed a quicker intubation time, fewer intubation attempts, and greater ease of intubation compared with the McGrath videolaryngoscope when used in patients with the Mallampati grade of ≥3.

The impact of pre-operative focused transthoracic echocardiography in emergency non-cardiac surgery patients with known or risk of cardiac disease.

This prospective observational study investigated the effect of focused transthoracic echocardiography in 99 patients who had suspected cardiac disease or were ≥ 65 years old, and were scheduled for emergency non-cardiac surgery. The treating anaesthetist completed a diagnosis and management plan before and after transthoracic echocardiography, which was performed by an independent operator. Clinical examination rated cardiac disease present in 75%; the remainder were asymptomatic. The cardiac diagnosis was changed in 67% and the management plan in 44% of patients after echocardiography. Cardiac disease was identified by echocardiography in 64% of patients, which led to a step-up of treatment in 36% (4% delay for cardiology referral, 2% altered surgery, 4% intensive care and 26% intra-operative haemodynamic management changes). Absence of cardiac disease in 36% resulted in a step-down of treatment in 8% (no referral 3%, intensive care 1% or haemodynamic treatment 4%). Pre-operative focused transthoracic echocardiography in patients admitted for emergency surgery and with known cardiac disease or suspected to be at risk of cardiac disease frequently alters diagnosis and management.

Randomized crossover study comparing quantitative fit tests between Trident™ and 3M™ Aura™ N95/P2 respirators.

BACKGROUND: Various styles of N95/P2 filtering facepiece respirators (FFRs) have been used by Australian healthcare workers (HCWs) during the COVID-19 pandemic. This is usually driven by the national stockpile availability. Many studies demonstrate three-panel flat-fold N95/P2 FFRs have higher quantitative fit test (QNFT) pass rates than other FFR styles. This prospective randomized crossover study utilized QNFT to evaluate the performance of the new three-panel flat-fold FFR, the Trident™ P2 respirator compared to the previously most effective model, the 3M™ Aura™ 9320A + N95 respirator. METHODS: We recruited 500 participants who completed online training and QNFT on both respirators. The order of the respirator being examined first was randomly allocated. The primary outcome was the QNFT pass rate. Secondary outcomes included the overall fit factor, the individual fit factor for each exercise, and the first-attempt QNFT pass rate. RESULTS: We found that both the overall and first-attempt QNFT pass rates of the Trident P2 respirator were significantly higher than the 3M Aura (99.2% vs 92.6%, p < 0.001; and 92.6% vs 76.4%, p < 0.001 respectively). The overall fit factor and the individual fit factor were also significantly higher for the Trident FFR than the 3M Aura. CONCLUSIONS: This study is the first to report hospital-based QNFT results of the Trident FFR, demonstrating very high first-time and overall pass rates. Our findings are consistent with previous research showing very high QNFT pass rates with three-panel flat-fold FFRs. These findings are important for pandemic preparedness with respect to the stockpiling and safe utilization of N95/P2 respirators.

Effect of intravenous parecoxib on post-craniotomy pain.

BACKGROUND: Pain management in craniotomy patients is challenging, with mild-to-moderate pain intensity, moderate-to-high risk of postoperative nausea and vomiting (PONV), and potentially catastrophic consequences of analgesic-related side-effects. The aim of this study was to determine whether i.v. parecoxib administered at dural closure during craniotomy decreased total morphine consumption and morphine-related side-effects compared with placebo. METHODS: One hundred adult patients presenting for supratentorial craniotomy under propofol/remifentanil anaesthesia were randomized to receive parecoxib, 40 mg i.v., or placebo in a double-blind manner. All patients received local anaesthetic scalp infiltration, regular i.v. paracetamol, nurse-administered morphine in the post-anaesthesia care unit (PACU) until verbal analogue pain scores were ≤4/10 and patient-controlled morphine thereafter. Morphine consumption, pain intensity, and analgesia-related side-effects were recorded during the first 24 h after operation. RESULTS: Ninety-six patients (49 control and 47 parecoxib) were included in the analyses. Fifty-nine (61%) patients received morphine in the PACU and only one patient (control) did not receive any morphine in the postoperative period. There were no significant differences between the two groups in morphine consumption [20 (range: 0-102) vs 16 (range: 1-92) mg; P=0.38], pain intensity [excellent/very good pain relief in 78% of parecoxib patients; 74% of control patients (P=0.72)] or analgesia-related side-effects (PONV in 51% of parecoxib patients; 56% of control patients; P=0.55) in the first 24 h after operation. No major morbidity was recorded. CONCLUSIONS: Our study demonstrated no clinical benefit to adding i.v. parecoxib to local anaesthetic scalp infiltration, i.v. paracetamol, and patient-controlled i.v. morphine after supratentorial craniotomy.

Predictors of airborne endotoxin concentrations in inner city homes.

Few studies have assessed in home factors which contribute to airborne endotoxin concentrations. In 85 inner city Baltimore homes, we found no significant correlation between settled dust and airborne endotoxin concentrations. Certain household activities and characteristics, including frequency of dusting, air conditioner use and type of flooring, explained 36-42% of the variability of airborne concentrations. Measurements of both airborne and settled dust endotoxin concentrations may be needed to fully characterize domestic exposure in epidemiologic investigations.

Changes in the H-1 histone complement during myogenesis. II. Regulation by differential coupling of H-1 variant mRNA accumulation to DNA replication.

We have shown that changes in proportions of the four chicken H-1's during in vitro myogenesis are primarily the result of differential coupling of their synthesis to DNA replication (see the previous paper). We show here that the four major chicken H-1's are encoded by distinct mRNAs which specify primary amino acid sequence variants. Accumulation of the H-1-variant mRNAs is coupled to DNA replication to different extents. The level of mRNA encoding H-1c (the H-1 variant that increases relative to the other H-1's in nondividing muscle cells) is completely uncoupled. In contrast, the level of mRNAs encoding H-1's a, b, and d (which have levels that decrease in nondividing muscle cells) are more tightly coupled. Polyadenylation is not involved in uncoupling H-1c mRNA accumulation from DNA replication.

The apolipoprotein A-I gene is actively expressed in the rapidly myelinating avian peripheral nerve.

The expression of the apolipoprotein A-I (apo A-I) gene was investigated in the myelinating sciatic nerve. Hybridization analysis with an apo A-I cDNA probe obtained from a cDNA library of mRNA isolated from rapidly myelinating chick sciatic nerve indicated that apo A-I coding transcripts increase during development in the chick sciatic nerve in parallel with the increase of myelin lamellae. Substantial apo A-I-like immunoreactivity in chick sciatic nerve homogenates was detected by Western blotting. The amount of antigen increased from the 15-d embryonic stage to 1 d posthatch and then decreased. Two subcellular fractions corresponding to the cytoplasmic compartments were particularly enriched in apo A-I. apo A-I immunoreactivity was also found in highly purified myelin preparations. Immunohistochemical staining provided further evidence for the presence of apo A-I in the endoneurial compartment of the sciatic nerve. Electron microscopic examination of these fractions after negative staining showed the presence of spherical and disc-shaped particles resembling high density lipoproteins. The presence of apo A-I, cholesterol esters, phospholipids, and triacylglycerols in ultracentrifugal fractions corresponding to serum lipoproteins and the behavior of apo A-I on nondenaturing gradient gels implied that apo A-I was associated with lipid. Studies with short-term organ cultures of sciatic nerves from 1-d chicks strengthened the evidence for local synthesis and secretion of apo A-I and apo A-I-containing lipoproteins by this tissue. These results establish that the apo A-I gene is actively expressed in developing sciatic nerve during the period of rapid myelination. These findings support the hypothesis that apo A-I synthesized within the nerve participates in the local transport of lipids used in myelin biosynthesis.

Glucan-induced modification of murine viral hepatitis.

Glucan, a macrophage stimulant, was evaluated for its ability to alter survival and phagocytic dysfunction in mice challenged with mouse hepatitis virus strain MHV-A59. Administration of glucan before the mice were challenged with the virus significantly prolonged median survival time but did not modify overall mortality compared with control mice given dextrose. Maximal effectiveness was achieved when glucan was administered both before and after the viral challenge. In contrast to the marked hepatic parenchymal cell necrosis observed in the control mice, glucan-treated mice exhibited reduced pathology. Intraperitoneal administration of MHV-A59 resulted in a significant depression of phagocytic activity compared with controls that were not exposed to the virus. The enhancement in phagocytic function in glucan-treated control mice was unaltered in virus-challenged, glucan-treated mice. Thus glucan is capable of increasing survival, inhibiting hepatic necrosis, and maintaining an activated state of phagocytic activity in mice challenged with MHV-A59. Macrophage stimulants may have a significant role in the modification of virally induced hepatic lesions.

Locus of the alpha-chain of the T-cell receptor is split by chromosome translocation in T-cell leukemias.

Mouse lymphoma cells were hybridized with two human acute T-cell leukemias with a t(11;14) (p13;q11) translocation and the segregated hybrids were examined for the presence of the DNA segments coding for the constant (C) and the variable (V) regions of the alpha chain (C alpha and V alpha) of the T-cell receptor. The C alpha segment was translocated to the involved chromosome 11 (11p+) while the V alpha segment remained on the involved chromosome 14 (14q-). The data indicate that the locus for the alpha chain of the T-cell receptor is split by the chromosomal breakpoint between the V alpha and the C alpha gene segments, and that the V alpha segments are proximal to the C alpha segment within chromosome band 14q11.2.

Independent developmental programs for two estrogen-regulated genes.

Measurement of hepatic apolipoprotein II and vitellogenin II messenger RNA during chicken embryogenesis showed that these genes acquire estrogen responsiveness at different stages of development. Sensitive solution hybridization assays with excess complementary DNA showed that apolipoprotein II transcripts were induced to 500 molecules per cell at day 9, whereas induction of vitellogenin II messenger RNA was not found until day 11. Thus, two estrogen regulated genes of common function and coordinately regulated in the adult may be on independent developmental programs.

Increased resistance to Staphylococcus aureus infection and enhancement in serum lysozyme activity by glucan.

Glucan is a potent reticuloendothelial stimulant whose immunobiological activity is mediated, in part, by an increase in the number and function of macrophages. In studying the role of glucan as a mediator of antibacterial activity, we attempted to ascertain the ability of glucan to modify the mortality of mice with experimentally induced Gram-positive bacteremia, and to enhance antibacterial defenses in rats as denoted by serum lysozyme and phagocytic activity. After intravenous administration of glucan, serum lysozyme concentrations were increased approximately sevenfold over control concentrations. The increase in serum lysozyme appeared to parallel the glucan-induced increase in phagocytosis and induced hyperplasia of macrophages. Prior treatment of mice with glucan significantly enhanced their survival when they were challenged systemically with Staphylococcus aureus. These studies indicate that glucan confers an enhanced state of host defense against bacterial infections.

Expression and characterization of recombinant interferon gamma (IFN-gamma) from the nine-banded armadillo (Dasypus novemcinctus) and its effect on Mycobacterium leprae-infected macrophages.

Armadillos (Dasypus novemcinctus) manifest the full histopathological spectrum of leprosy, and are hosts of choice for in vivo propagation of Mycobacterium leprae. Though potentially useful as a model of leprosy pathogenesis, few armadillo-specific reagents exist. We have identified a region of high homology to the interferon gamma (IFN-gamma) of other mammals within the recently published armadillo whole genomic sequence. cDNA was made from ConA-stimulated armadillo peripheral blood mononuclear cells (PBMC), amplified, and cloned into a pET expression vector for transformation and over-expression in Escherichia coli. The recombinant protein (rDnIFN-gamma) was characterized by western blot and its biological function confirmed with bioassays including intracellular killing of Toxoplasma gondii and induction of indoleamine 2, 3-dioxygenase activity. In using rIFN-gamma to activate macrophages from mice, humans or armadillos, similar to humans, rIFN-gamma-activated armadillo MPhi did not produce nitrite and or inhibit the viability of M. leprae in vitro. Conversely, murine rIFN-gamma-activated mouse MPhi produced high levels of nitrite and killed intracellular M. leprae in vitro. These data indicate that the response of armadillo MPhi to rDnIFN-gamma is similar to that which occurs in humans, and demonstrates a potentially important value of the armadillo as a model in leprosy research.

Tyzzer's disease in a Eurasian otter (Lutra lutra) in Scotland.

A Eurasian otter (Lutra lutra) cub found in weak condition on the Isle of Harris, Scotland, developed bilateral corneal oedema 16 days after being admitted to a rehabilitation centre. It died unexpectedly on day 26. On postmortem examination, there was excess clear fluid in the body cavities and the liver was swollen with numerous pale focal lesions and petechial haemorrhages throughout. Histopathological examination revealed bundles of bacilli morphologically typical of Clostridium piliforme within hepatocytes. Comparative analysis of the nucleotide base sequence of a 16S rdna fragment amplified from the infected liver tissue revealed that it was identical to a C piliforme 16S rdna sequence. The possibility of concurrent infection with canine adenovirus type 1 was considered but none of the characteristic histopathological lesions was observed and examination of the liver by transmission electron microscopy was negative for virus particles. This appears to be the first record of Tyzzer's disease in an otter and the first in a wild animal in Britain.

Optimising tear replacement rheology in canine keratoconjunctivitis sicca.

Dry eye is a substantial problem in a large number of human and canine patients. Numerous laboratory models for tear deficiency exist using genetically predisposed rodent models, animals treated with topical anti-muscarinics, or those kept in environments with increased air flow to produce the ocular surface changes seen in human patients. Canine keratoconjunctivitis sicca, seen in many thousands of dogs kept as companion animals, can provide a valuable spontaneous model for testing tear replacement medications that might better model disease in human patients, existing as it does in an outbred population that live in the same environments as their owners. Here the development of a crosslinked hyaluronic acid topical drop is described together with the results of trials on dogs with spontaneous keratoconjunctivitis sicca. Although hyaluronic acid in its native form in tear replacement drops shows a Newtonian rheology, the crosslinked product described here behaves in a non-Newtonian manner, with the same shear thinning shown by the tear film itself. The crosslinked product thus shows itself as a potentially valuable tear replacement medication for the human dry eye population as well as for dogs with the same condition.

A randomised controlled trial comparing fibreoptic-guided tracheal intubation through two supraglottic devices: Ambu® AuraGain™ laryngeal mask and LMA® Fastrach™.

The Ambu®AuraGain™ laryngeal mask (LM) (Ambu A/S, Ballerup, Denmark) is one of the few readily available second-generation supraglottic airway devices (SADs) that offer a conduit for fibreoptic-guided endotracheal intubation. We aimed to compare fibreoptic intubation through this device with the LMA® (laryngeal mask airway) Fastrach™ (Teleflex Medical, Co. Westmeath, Ireland), which has been a recommended dedicated rescue device for the management of the unanticipated difficult airway. This randomised controlled trial compared a previously described fibreoptic score in 116 patients with no known airway pathology, who had asleep fibreoptic endotracheal intubation via either the AuraGain LM or the LMA Fastrach. Time, ease and success rate of SAD and endotracheal tube (ETT) insertion and complications were recorded. The AuraGain LM demonstrated better laryngeal alignment with 29 out of 59 patients in the AuraGain LM (AG) group having a Grade 4 view (only vocal cords visible), compared to 20 out of 54 patients in the LMA Fastrach (FT) group (P=0.003). It allowed significantly quicker and easier ETT intubation when used as a conduit. The AuraGain LM was also quicker to insert compared to the Fastrach LMA. Similar rates of minor complications, such as sore throat and dysphonia occurred in both groups. Our study indicates that when used in patients with complete muscle relaxation and no known airway pathology, the AuraGain LM achieves better laryngeal alignment and quicker, easier and more successful fibreoptic-guided ETT intubation than the Fastrach LMA.

Macrophages from nephrotic rats regulate apolipoprotein E biosynthesis and cholesterol content independently.

The effects of the nephrotic syndrome in rats on the cholesterol content and the biosynthesis of apolipoprotein E (apoE) by resident peritoneal macrophages have been investigated. Since the nephrotic syndrome has been associated with an increased risk of coronary atherosclerosis, we hypothesized that macrophages from nephrotic rats would accumulate cholesterol and undergo transformation into foam cells, with a concomitant increase in apoE biosynthesis. The nephrotic syndrome was induced in rats with puromycin aminonucleoside. Peritoneal macrophages exposed in vivo for 7-21 d to ascites fluid derived from plasma containing sixfold elevations of lipoproteins did not accumulate unesterified or esterified cholesterol. Nevertheless, immunoprecipitation assays after incubation of the isolated cells with [35S]methionine, or immunoblot analysis of the incubation medium demonstrated a 2.6-fold increase in apoE secretion compared with normal macrophages. This increase was accompanied by 5- to 10-fold increases in cellular apoE messenger RNA as determined by quantitative solution hybridization assay. Peritoneal macrophages cultured from nephrotic rats during the period of hypercholesterolemia also showed distinct and highly reproducible morphologic changes. The dissociation between apoE biosynthesis and macrophage cholesterol content provides new insight into the response of peritoneal macrophages in vivo to endogenous hyperlipemia.

Apolipoprotein A-I is required for cholesteryl ester accumulation in steroidogenic cells and for normal adrenal steroid production.

In addition to its ability to remove cholesterol from cells, HDL also delivers cholesterol to cells through a poorly defined process in which cholesteryl esters are selectively transferred from HDL particles into the cell without the uptake and degradation of the lipoprotein particle. The HDL-cholesteryl ester selective uptake pathway is known to occur in human, rabbit, and rodent hepatocytes where it may contribute to the clearance of plasma cholesteryl ester. The selective uptake pathway has been studied most extensively in steroidogenic cells of rodents in which it accounts for 90% or more of the cholesterol destined for steroid production or cholesteryl ester accumulation. In this study we have used apo A-I-, apo A-II-, and apo E-deficient mice created by gene targeting in embryonic stem cells to test the importance of the three major HDL proteins in determining cholesteryl ester accumulation in steroidogenic cells of the adrenal gland, ovary, and testis. apo E and apo A-II deficiencies were found to have only modest effects on cholesteryl ester accumulation. In contrast, apo A-I deficiency caused an almost complete failure to accumulate cholesteryl ester in steroidogenic cells. These results suggest that apo A-I is essential for the selective uptake of HDL-cholesteryl esters. The lack of apo A-I has a major impact on adrenal gland physiology causing diminished basal corticosteroid production, a blunted steroidogenic response to stress, and increased expression of compensatory pathways to provide cholesterol substrate for steroid production.