Myological and osteological approaches to gape and bite force reconstruction in Smilodon fatalis.

Masticatory gape and bite force are important behavioral and ecological variables. While much has been written about the highly derived masticatory anatomy of Smilodon fatalis, there remains a great deal of debate about their masticatory behaviors. To that end, we establish osteological proxies for masticatory adductor fascicle length (FL) based on extant felids and apply these along with previously validated techniques to S. fatalis to provide estimates of fascicle lengths, maximum osteological gapes, and bite force. While the best correlated FL proxies in extant felids do not predict particularly long fascicles, these proxies may be of value for less morphologically distinct felids. A slightly less well correlated proxy predicts a temporalis FL 15% longer than that of Panthera tigris. While angular maximum bony gape is significantly larger in S. fatalis than it is in extant felids, linear gape at the canine tip and carnassial notch were not significantly different from those of extant felids. Finally, we produce anatomical bite force estimates of 1283.74 N at the canine and 4671.41 N at the carnassial, which are similar in magnitude to estimates not of the largest felids but of the much smaller P. onca, with S. fatalis producing slightly less force at the canines and more at the carnassials. These estimates align with previous predictions that S. fatalis may have killed large prey with canine shearing bites produced, in part, by force contributions of the postcranial muscles.

Increased brain microvascular hemoglobin concentrations in children with cerebral malaria.

Brain swelling is associated with death from cerebral malaria, but it is unclear whether brain swelling is caused by cerebral edema or vascular congestion-two pathological conditions with distinct effects on tissue hemoglobin concentrations. We used near-infrared spectroscopy (NIRS) to noninvasively study cerebral microvascular hemoglobin concentrations in 46 Malawian children with cerebral malaria. Cerebral malaria was defined by the presence of the malaria parasite Plasmodium falciparum on a blood smear, a Blantyre coma score of 2 or less, and retinopathy. Children with uncomplicated malaria (n = 33) and healthy children (n = 29) were enrolled as comparators. Cerebral microvascular hemoglobin concentrations were higher among children with cerebral malaria compared with those with uncomplicated malaria [median (25th, 75th): 145.2 (95.2, 190.0) µM versus 82.9 (65.7, 105.4) µM, P = 0.008]. Cerebral microvascular hemoglobin concentrations correlated with brain swelling score determined by MRI (r = 0.37, P = 0.03). Fluctuations in cerebral microvascular hemoglobin concentrations over a 30-min time period were characterized using detrended fluctuation analysis (DFA). DFA determined self-similarity of the cerebral microvascular hemoglobin concentration signal to be lower among children with cerebral malaria compared with those with uncomplicated malaria [0.63 (0.54, 0.70) versus 0.91 (0.82, 0.94), P < 0.0001]. The lower self-similarity of the hemoglobin concentration signal in children with cerebral malaria suggested impaired regulation of cerebral blood flow. The elevated cerebral tissue hemoglobin concentration and its correlation with brain swelling suggested that excess blood volume, potentially due to vascular congestion, may contribute to brain swelling in cerebral malaria.

Oral Lisinopril Raises Tissue Levels of ACE2, the SARS-CoV-2 Receptor, in Healthy Male and Female Mice.

Angiotensin-converting enzyme 2 (ACE2) is the established cellular receptor for SARS-CoV-2. However, it is unclear whether ACE1 inhibitors (e.g., lisinopril) or angiotensin receptor blockers (e.g., losartan) alter tissue ACE2 expression. This study sought to determine whether lisinopril or losartan, as monotherapies or in combination, changes tissue levels of ACE2 in healthy male and female mice. Mice received lisinopril (10 mg/kg/day), losartan (10 mg/kg/day), or both for 21 days via drinking water. A control group received water without drug. The ACE2 protein index (ACE2 protein/total protein) was determined on the small intestine, lung, kidney, and brain. Oral lisinopril increased the ACE2 protein index across all tissues (p < 0.0001 vs. control). In contrast, the combination of lisinopril plus losartan did not increase ACE2 levels in any tissue (p = 0.89 vs. control) and even decreased tissue expression of the Ace2 gene (p < 0.001 vs. control). Tissue ACE2 remained elevated in the mice 21 days after cessation of lisinopril (p = 0.02). Plasma ACE2 did not correlate with the ACE2 protein index in any tissue. A sex difference was observed: kidney ACE2 levels were higher in male than in female mice (p < 0.0001). Oral lisinopril increases ACE2, the cellular receptor for SARS-CoV-2, in tissues that are relevant to the transmission and pathogenesis of COVID-19. Remarkably, the addition of losartan prevented lisinopril-induced increases in ACE2 across tissues. These results suggest that ACE inhibitors and angiotensin receptor blockers interact to determine tissue levels of ACE2.

Experimental Babesia rossi infection induces hemolytic, metabolic, and viral response pathways in the canine host.

BACKGROUND: Babesia rossi is a leading cause of morbidity and mortality among the canine population of sub-Saharan Africa, but pathogenesis remains poorly understood. Previous studies of B. rossi infection were derived from clinical cases, in which neither the onset of infection nor the infectious inoculum was known. Here, we performed controlled B. rossi inoculations in canines and evaluated disease progression through clinical tests and whole blood transcriptomic profiling. RESULTS: Two subjects were administered a low inoculum (104 parasites) while three received a high (108 parasites). Subjects were monitored for 8 consecutive days; anti-parasite treatment with diminazene aceturate was administered on day 4. Blood was drawn prior to inoculation as well as every experimental day for assessment of clinical parameters and transcriptomic profiles. The model recapitulated natural disease manifestations including anemia, acidosis, inflammation and behavioral changes. Rate of disease onset and clinical severity were proportional to the inoculum. To analyze the temporal dynamics of the transcriptomic host response, we sequenced mRNA extracted from whole blood drawn on days 0, 1, 3, 4, 6, and 8. Differential gene expression, hierarchical clustering, and pathway enrichment analyses identified genes and pathways involved in response to hemolysis, metabolic changes, and several arms of the immune response including innate immunity, adaptive immunity, and response to viral infection. CONCLUSIONS: This work comprehensively characterizes the clinical and transcriptomic progression of B. rossi infection in canines, thus establishing a large mammalian model of severe hemoprotozoal disease to facilitate the study of host-parasite biology and in which to test novel anti-disease therapeutics. The knowledge gained from the study of B. rossi in canines will not only improve our understanding of this emerging infectious disease threat in domestic dogs, but also provide insight into the pathobiology of human diseases caused by Babesia and Plasmodium species.

RESPECT: Radiology Employees Striving for Productive and Effective Communication.

Ineffective communication is commonly listed as a root cause of sentinel events and other adverse events in the health care setting. The psychological safety of all employees is considered to be a factor that promotes effective communication. Recently, leaders of a radiology department learned that many of the frontline staff did not feel they were being treated respectfully by radiologists during routine interactions. On a baseline survey, only 48% of technologists, reading room assistants, and child life specialists rated their interactions with radiologists as very good or excellent. An improvement team was formed, representing radiologists, technologists, reading room assistants, and child life specialists throughout the department. The improvement team launched a series of interventions with a goal of increasing the percentage of interactions rated as very good or excellent from 48% to 90%. The improvement team focused interventions on three topics: in-person interactions, telephone interactions, and trainee interactions. By the time of this publication, the median percentage of interactions rated as very good or excellent improved to 75%, with a maximum surveyed value of 90%.Online supplemental material is available for this article.©RSNA, 2020.

Using informatics to engage patients.

As a specialty, radiology has spent much of the last two decades implementing information systems that improve departmental efficiency and the ordering provider's access to information. While our patients have realized benefits such as improved access to care and reduced turnaround times, there has been little focus on using these information systems to improve patient engagement. In the last decade, society has shifted. Now, consumers in every industry expect to be able to use technology to help them accomplish different tasks from scheduling to communicating. Medicine, in general, has been slow to respond to the concept of the patient as a consumer. In this manuscript we describe some of the informatics efforts we have employed in our department to improve patient engagement. We present these initiatives, corresponding to each aspect of the radiology value stream, from the patient's point of view.

High-resolution SOFIA/EXES Spectroscopy of SO2 Gas in the Massive Young Stellar Object MonR2 IRS3: Implications for the Sulfur Budget.

Sulfur has been observed to be severely depleted in dense clouds leading to uncertainty in the molecules that contain it and the chemistry behind their evolution. Here, we aim to shed light on the sulfur chemistry in young stellar objects (YSOs) by using high-resolution infrared spectroscopy of absorption by the ν 3 rovibrational band of SO2 obtained with the Echelon-Cross-Echelle Spectrograph on the Stratospheric Observatory for Infrared Astronomy. Using local thermodynamic equilibrium models we derive physical parameters for the SO2 gas in the massive YSO MonR2 IRS3. This yields a SO2/H abundance lower limit of 5.6 ± 0.5 × 10-7, or >4% of the cosmic sulfur budget, and an intrinsic line width (Doppler parameter) of b < 3.20 km s-1. The small line widths and high temperature (T ex = 234 ± 15 K) locate the gas in a relatively quiescent region near the YSO, presumably in the hot core where ices have evaporated. This sublimation unlocks a volatile sulfur reservoir (e.g., sulfur allotropes as detected abundantly in comet 67P/Churyumov-Gerasimenko), which is followed by SO2 formation by warm, dense gas-phase chemistry. The narrowness of the lines makes formation of SO2 from sulfur sputtered off grains in shocks less likely toward MonR2 IRS3.

Anatomy of screw dislocations in nanoporous SAPO-18 as revealed by atomic force microscopy.

Defects in solids are often the source of functional activity, the trigger for crystal growth and the seat of instability. Screw dislocations are notoriously difficult to study by electron microscopy. Here we decipher the complex anatomy of one such defect in the industrially important nanoporous catalyst SAPO-18 by atomic force microscopy.

Atomic force microscopy of novel zeolitic materials prepared by top-down synthesis and ADOR mechanism.

Top-down synthesis of 2D materials from a parent 3D zeolite with subsequent post-synthetic modification is an interesting method for synthesis of new materials. Assembly, disassembly, organisation, reassembly (ADOR) processes towards novel materials based on the zeolite UTL are now established. Herein, we present the first study of these materials by atomic force microscopy (AFM). AFM was used to monitor the ADOR process through observation of the changes in crystal surface and step height of the products. UTL surfaces were generally complex and contained grain boundaries and low-angle intergrowths, in addition to regular terraces. Hydrolysis of UTL to IPC-1P did not have adverse effects on the surfaces as compared to UTL. The layers remained intact after intercalation and calcination forming novel materials IPC-2 and IPC-4. Measured step heights gave good correlation with the X-ray diffraction determined d200 -spacing in these materials. However, swelling gave rise to significant changes to the surface topography, with significantly less regular terrace shapes. The pillared material yielded the roughest surface with ill-defined surface features. The results support a mechanism for the majority of these materials in which the UTL layers remain intact during the ADOR process as opposed to dissolving and recrystallising during each step.

Lipid rafts and caveolin-1 coordinate interleukin-1beta (IL-1beta)-dependent activation of NFkappaB by controlling endocytosis of Nox2 and IL-1beta receptor 1 from the plasma membrane.

Recent evidence suggests that signaling by the proinflammatory cytokine interleukin-1beta (IL-1beta) is dependent on reactive oxygen species derived from NADPH oxidase. Redox signaling in response to IL-1beta is known to require endocytosis of its cognate receptor (IL-1R1) following ligand binding and the formation of redox-active signaling endosomes that contain Nox2 (also called redoxosomes). The consequent generation of reactive oxygen species by redoxosomes is responsible for the downstream recruitment of IL-1R1 effectors (IRAK, TRAF6, and IkappaB kinase kinases) and ultimately for activation of the transcription factor NFkappaB. Despite this knowledge of the signaling events that occur downstream of redoxosome formation, an understanding of the mechanisms that coordinate the genesis of redoxosomes following IL-1beta stimulation has been lacking. Here, we demonstrate that lipid rafts play an important role in this process. We show that Nox2 and IL-1R1 localize to plasma membrane lipid rafts in the unstimulated state and that IL-1beta signals caveolin-1-dependent endocytosis of both proteins into the redoxosome. We also show that inhibiting lipid raft-mediated endocytosis prevents NFkappaB activation. Finally, we demonstrate that Vav1, a Rac1 guanine exchange factor and activator of Nox2, is recruited to lipid rafts following IL-1beta stimulation and that it is required for NFkappaB activation. Our results fill in an important mechanistic gap in the understanding of early IL-1R1 and Nox2 signaling events that control NFkappaB activation, a redox-dependent process important in inflammation.

BmeRABC5 is a multidrug efflux system that can confer metronidazole resistance in Bacteroides fragilis.

The RND-family efflux pump gene bmeB5 was previously shown to be overexpressed in metronidazole-resistant laboratory mutants of Bacteroides fragilis. In the present study, we characterized the bmeABC5 genes and an upstream putative TetR-family regulator gene (bmeR5). bmeR5 (645 bp) was located 51 bp upstream of bmeA5 and encoded a 24.9-kDa protein. Deletant strains lacking bmeB5 or bmeR5 were constructed from a wild-type B. fragilis strain ADB77. Strain antimicrobial susceptibility was determined and gene expression was quantified. bmeR5 was overexpressed in Escherichia coli using a 6x-His tag system; BmeR5-His6 was isolated from inclusion bodies and its binding to bmeABC5 promoter regions was determined. BmeR5-His6 bound specifically to the bmeR5-bmeC5 intergenic region (IT1). Deletion of bmeR5 (ADB77DeltabmeR5) resulted in a significant (p < 0.05) increase in expression of bmeA5, bmeB5, and bmeC5, and > two-fold increase in minimum inhibitory concentrations (MICs) of ampicillin, cefoxitin, cefoperazone, ciprofloxacin, imipenem, metronidazole, ethidium bromide, and sodium dodecyl sulfate (SDS). MICs were reduced by the efflux pump inhibitor carbonyl cyanide m-chlorophenyl hydrazone (CCCP). The MICs of ampicillin, cefoperazone, metronidazole, and SDS were reduced by approximately two-fold in ADB77DeltabmeB5. A multidrug (metronidazole)-resistant, nim-negative B. fragilis clinical isolate overexpressed bmeABC5 genes, had a G-->T point mutation in IT1, and significantly reduced binding to BmeR5-His6. These data demonstrate that BmeR5 is a local repressor of bmeABC5 expression and that mutations in IT1 can lead to a derepression and resistance to multiple antimicrobial agents, including metronidazole.

Clinical significance of overexpression of multiple RND-family efflux pumps in Bacteroides fragilis isolates.

OBJECTIVES: The aim of the present study was to determine correlation between bmeB efflux pump overexpression and resistance to fluoroquinolones and beta-lactams in Bacteroides fragilis clinical isolates (n = 51) and the effects of broad-spectrum efflux pump inhibitors (EPIs) on the MICs of the test antibiotics. METHODS: Susceptibility to garenoxacin, levofloxacin, moxifloxacin, cefoxitin and faropenem +/- EPIs (CCCP, MC-207,110, reserpine and verapamil) was determined. Expression of bmeB efflux pumps was measured, topoisomerase genes were sequenced and beta-lactamase production was determined. RESULTS: Isolates were grouped into categories based on susceptibility patterns, topoisomerase sequence and efflux pump expression. Panel I isolates (19/51, 37.3%) were highly resistant to fluoroquinolones and cefoxitin (resistance to all agents was significantly reduced by EPIs, P < 0.05), had a point mutation in gyrA (C-->T) causing a Ser-82-->Phe substitution, and overexpressed bmeB4 and bmeB15. Panel II isolates (7/51; 13.7%) had intermediate-level resistance to fluoroquinolones and cefoxitin and a GyrA substitution. Panel IIIA isolates (21/51; 41.2%) had intermediate-level fluoroquinolone resistance and high-level cefoxitin resistance [resistance to all agents was significantly reduced by EPIs (P < 0.05)] and overexpressed bmeB4 and bmeB15. Panel IIIB isolates (4/51; 7.8%) had low-level fluoroquinolone resistance and high-level resistance to cefoxitin [cefoxitin resistance was significantly reduced by EPIs (P < 0.05)] and overexpressed bmeB4, bmeB6, bmeB10 and bmeB14. All isolates were beta-lactamase-positive. CONCLUSIONS: These data suggest that bmeB efflux pump overexpression can (i) cause low- to intermediate-level clinically relevant fluoroquinolone resistance; (ii) be coupled with GyrA substitutions to cause high-level fluoroquinolone resistance; (iii) contribute to high-level clinically relevant resistance to beta-lactams.

Bacteroides fragilis BmeABC efflux systems additively confer intrinsic antimicrobial resistance.

OBJECTIVES: To determine the prevalence of expression and function(s) of Bacteroides fragilis RND family efflux transport systems (bmeABC1-16). METHODS: The mRNA transcripts of bmeB efflux pump genes were detected in a wild-type strain ADB77 by RT-PCR and expression in different strains was quantified by comparative quantitative real-time RT-PCR. In order to determine independent or additive functions, BmeB 1, 3, 12 and 15 (the first efflux pumps identified) were deleted as singles, doubles, triples or quadruples by the double cross-over technique with pADB242 and antimicrobial susceptibility was assayed by the spiral gradient endpoint technique. RESULTS: All efflux pumps except bmeB9 were expressed in the wild-type parental strain. Susceptibility to beta-lactams, fluoroquinolones, ethidium bromide, SDS and triclosan was increased in ADB77DeltabmeB3 (up to 3-fold) and ADB77DeltabmeB1DeltabmeB3DeltabmeB12 (up to 5-fold). Expression of bmeB9 was increased and that of bmeB11 repressed in the latter deletant. A quadruple deletant (ADB77DeltabmeB1DeltabmeB3DeltabmeB12DeltabmeB15) had similar changes as well as a 2-fold increase in expression of bmeB16 and norfloxacin resistance. Expression of bmeB3 was increased in two triple deletants ADB77DeltabmeB1DeltabmeB12DeltabmeB15-type I (2-fold) and ADB77DeltabmeB1DeltabmeB12DeltabmeB15-type II (5.8-fold). Antimicrobial MICs were also increased in the latter deletant; ampicillin (2.6-fold), cefoperazone (3.4-fold), cefoxitin (1.8-fold), tetracycline (36.4-fold), SDS (1.7-fold) and triclosan (2-fold). CONCLUSIONS: These data demonstrate that constitutive bmeB expression is prevalent in B. fragilis. At least seven BmeB efflux pumps are functional in transporting antimicrobials and have overlapping substrate profiles, and at least four confer intrinsic resistance.