Healthcare staff perceptions towards influenza and potential COVID-19 vaccination in the 2020 pandemic context

The COVID-19 pandemic generated renewed focus on infectious disease transmission in healthcare settings. This study aimed to evaluate staff perceptions towards influenza vaccination in the COVID-19 context. All healthcare workers within a major UK tertiary referral hospital were invited to answer a survey conducted from September 2^nd to 13^th, 2020. In all, 593 responses were received across a spectrum of roles; 44% reported they were more likely to get an influenza vaccine this year due to COVID-19; however, 10% felt that an influenza vaccine was less important due to social distancing. Additional questions evaluated intention to receive COVID-19 vaccination. There were substantial differences of opinion between staff groups.

Nosocomial outbreak of measles amongst a highly vaccinated population in an English hospital setting

In May 2017 a patient attended the emergency department at a hospital in England, with a presumed allergic reaction. He was subsequently diagnosed with measles. There were seven further confirmed cases, five of whom had received two doses of MMR vaccine. This outbreak highlights the importance of not relying on vaccination status to rule out the diagnosis of measles. Epidemiological investigations of this outbreak were particularly challenging due to the highly infectious nature of the measles virus, and prevented full elucidation of either the source of this outbreak or the transmission pathways.

Morphological and Biochemical Features Affecting the Antithrombotic Properties of the Aorta in Adult Rabbits and Rabbit Pups

We hypothesised that there are important physiologic differences in arterial wall structure and function with respect to antithrombotic activity in the very young (pre-puberty) compared to adults. Electron microscopy, gel electrophoresis, and activity assays were used to examine differences in aorta structure and function comparing prepubertal rabbits (pups) to adult rabbits. Differences in endothelial function, extracellular matrix structure, proteoglycan (PG) distribution and glycosaminoglycan (GAG) content and function were shown. In both intima and media, total PG, chondroitin sulfate (CS) PG and heparan sulfate (HS) PG content were significantly increased in pups compared to adult rabbits. These findings corresponded to increased concentrations by mass analyses of CS GAG and DS GAG in aortas from pups. There was also a significant increase in antithrombin activity in pups due to HS GAG. In conclusion, differences in both structure and antithrombin activity of aortas from pups compared to adult rabbits suggest that young arteries may have greater antithrombotic potential that is, at least in part, related to increased HS GAG.

Aciclovir-induced neurotoxicity: Utility of CSF and serum CMMG levels in diagnosis

Aciclovir is an anti-viral frequently used for herpes virus infections. Neurotoxicity and nephrotoxicity are uncommon but serious side effects of aciclovir treatment. This case illustrates how aciclovir induced neurotoxicity can present and how it can be diagnosed using quantitative assays of aciclovir and its metabolite in the CSF and serum.

Sex differences in sensitivity to the depressive-like effects of the kappa opioid receptor agonist U-50488 in rats

BACKGROUND

Dynorphin, an endogenous ligand at kappa opioid receptors (KORs), produces depressive-like effects and contributes to addictive behavior in male nonhuman primates and rodents. Although comorbidity of depression and addiction is greater in women than men, the role of KORs in female motivated behavior is unknown.

METHODS

In adult Sprague-Dawley rats, we used intracranial self-stimulation to measure effects of the KOR agonist (±)-trans-U-50488 methanesulfonate salt (U-50488) (.0-10.0 mg/kg) on brain stimulation reward in gonadally intact and castrated males and in females at estrous cycle stages associated with low and high estrogen levels. Pharmacokinetic studies of U-50488 in plasma and brain were conducted. Immunohistochemistry was used to identify sex-dependent expression of U-50488-induced c-Fos in brain.

RESULTS

U-50488 dose-dependently increased the frequency of stimulation (threshold) required to maintain intracranial self-stimulation responding in male and female rats, a depressive-like effect. However, females were significantly less sensitive than males to the threshold-increasing effects of U-50488, independent of estrous cycle stage in females or gonadectomy in males. Although initial plasma concentrations of U-50488 were higher in females, there were no sex differences in brain concentrations. Sex differences in U-50488-induced c-Fos activation were observed in corticotropin releasing factor-containing neurons of the paraventricular nucleus of the hypothalamus and primarily in non-corticotropin releasing factor-containing neurons of the bed nucleus of the stria terminalis.

CONCLUSIONS

These data suggest that the role of KORs in motivated behavior of rats is sex-dependent, which has important ramifications for the study and treatment of mood-related disorders, including depression and drug addiction in people.

Generating CTLs against the subdominant EBV LMP antigens by transient expression of an A20 inhibitor with EBV LMP proteins in human DCs

Epstein-Barr virus (EBV) infection leads to Hodgkin’s disease (HD) in some immunocompetent hosts. The malignant Reed-Sternberg cells of HD only express a limited array of subdominant EBV antigens to evade preexisting immune responses to EBV. The EBV-encoded latent membrane proteins (LMP1 and LMP2), which are expressed by HD and various EBV-associated malignancies, have been proposed as a potential target for CTL-based therapy. However, the precursor frequency for LMP-specific CTL is generally low in healthy EBV-infected hosts, and immunotherapy based on these antigens is often compromised by the poor immunogenicity and the oncogenic potential. In the present study, we report that transitively expressing an inhibitor of A20, a key negative regulator of inflammatory signaling pathways, together with the LMP antigens (truncated LMP1 and full-length LMP2) greatly enhances maturation and cytokine production of human (h) monocyte-derived dendritic cells (DCs). As a consequence, LMP1/2-expressed, A20-silenced hDCs have an enhanced potency to prime LMP-specific T cell response. When the in vitro primed T cells are adoptively transferred into tumor-xenografted, severe combined immunodeficient (SCID) mice, some of the xenografted tumors approach complete regression. Thus, the study may provide an available resource of LMP-specific T cells for T cell immunotherapy.

Gender effects on rat metabolism of AMG 900, an orally available small molecule aurora kinase inhibitor

AMG 900 is an orally available small molecule that is highly potent and selective as a pan-aurora kinase inhibitor. AMG 900 is currently undergoing phase 1 clinical evaluation in patients with advanced solid tumors. The metabolism of AMG 900 was investigated in both male and female rats. We conducted studies in bile-duct catheterized (BDC) rats where bile, urine and plasma were analyzed to obtain metabolism profiles for each gender. These studies identified gender differences in the metabolism profiles in bile. Bile contained the majority of the drug related material and contained little unchanged AMG 900 which indicated that metabolism was the prominent process in drug elimination. Although bile contained the same metabolites for both genders, the amount of specific metabolites differed. Male rats metabolized AMG 900 primarily through hydroxylation with subsequent sulfate conjugation on the pyrimidinyl-pyridine side-chain whereas female rats favored a different oxidation site on the thiophene ring's methyl group, which is then metabolized to a carboxylic acid with subsequent conjugation to an acyl glucuronide. CYP phenotyping identified the prominent isoforms as being gender specific or biased in the oxidative metabolism of AMG 900. The metabolism in male rats favored both CYP2C11 and CYP2A2 whereas females favored the CYP2C12. The prominent sulfate conjugate identified in the male rat bile could also be due to male biased metabolism since it has been reported that sulfate conjugation is more prevalent in male rats. All the prominent rat metabolism routes for AMG 900 either have male or female bias. These differences in the rat AMG 900 metabolism profiles in bile can be explained by gender specific P450CYP isoforms.

Management of post cholecystectomy Mirizzi's syndrome

Various strategies have been proposed for the management of retained calculi within the biliary tree following cholecystectomy. We present a unique case of a cystic duct remnant calculus causing Mirizzi syndrome, only the fourth such case of its kind. An open procedure was planned, however the calculus was eventually extracted endoscopically. The pathophysiology and management of Mirizzi syndrome and retained calculi within the cystic duct remnant are discussed along with the merits of a minimally invasive approach.

Abstract 2663: Preclinical pharmacokinetic characterizations and human pharmacokinetic prediction of AMG 900, an orally available small molecule inhibitor of aurora kinases

Introduction: AMG 900 is a small molecule being developed as an orally administered, highly potent and selective pan-aurora kinase inhibitor. AMG 900 is currently undergoing phase 1 clinical evaluation in patients with advanced solid tumors. The objectives of the studies were to characterize single dose pharmacokinetics (PK) of AMG 900 in preclinical species and use the preclinical PK data to predict its human PK. Methods: Following a single intravenous and oral administration of AMG 900 to mice, rats, dogs, and monkeys, blood samples were collected and processed for plasma by centrifugation. AMG 900 plasma concentrations were determined by LC-MS/MS. Non-compartmental analysis of the concentration - time data was performed to calculate PK parameters of AMG 900. Human PK were predicted based on data from preclinical species using the simple allometric scaling method assuming a human body weight of 60 kg. Results: AMG 900 exhibited low (mouse, monkey and dog) to moderate (rat) clearance in the species evaluated. The volume of distribution at steady state was less than 0.5 L/kg across species. Following intravenous administration, the compound had terminal elimination half-life ranging from 0.6 to 2.4 hours. AMG 900 was well absorbed in fasted animals across species with an oral bioavailability ranging from 31% to 104%. The clearance and volume of distribution at steady state in humans were predicted to be 0.03 L/hr/kg and 0.1 L/kg, respectively, with the predicted half-life to be approximately 2.3 hours. Bioavailability after oral administration of AMG 900 was predicted to be 75%, calculated from the mean values observed in non-clinical species. Conclusion: AMG 900 exhibits good PK properties in preclinical species and it was predicted to have low clearance and good oral bioavailability in human. Available PK results from the on-going phase 1 trial are consistent with the allometric scaling predictions.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2663.

Discovery and optimization of potent and selective triazolopyridazine series of c-Met inhibitors

Deregulation of the receptor tyrosine kinase c-Met has been implicated in several human cancers and is an attractive target for small molecule drug discovery. We previously showed that O-linked triazolopyridazines can be potent inhibitors of c-Met. Herein, we report the discovery of a related series of N-linked triazolopyridazines which demonstrate nanomolar inhibition of c-Met kinase activity and display improved pharmacodynamic profiles. Specifically, the potent time-dependent inhibition of cytochrome P450 associated with the O-linked triazolopyridazines has been eliminated within this novel series of inhibitors. N-linked triazolopyridazine 24 exhibited favorable pharmacokinetics and displayed potent inhibition of HGF-mediated c-Met phosphorylation in a mouse liver PD model. Once-daily oral administration of 24 for 22days showed significant tumor growth inhibition in an NIH-3T3/TPR-Met xenograft mouse efficacy model.

Acquisition and eradication of P. aeruginosa in young children with cystic fibrosis

When do infants and young children with cystic fibrosis acquire infection with Pseudomonas aeruginosa? Can this be eradicated when first detected? Children <6 yrs of age participated in an annual bronchoalveolar lavage (BAL)-based microbiological surveillance programme in Perth, Australia. When P. aeruginosa was detected, an eradication programme using combination treatment with i.v., oral and nebulised antibiotics was undertaken. Repeat BAL was performed 3 months following treatment, to assess eradication success. P. aeruginosa was detected in 33 (28.4%) children; median (range) age at detection was 30.5 (3.3-71.4) months. P. aeruginosa was mucoid at detection in six (18.2%) out of 33 patients and associated with respiratory symptoms in 16 (48.5%) out of 33 children. In total, 26 children underwent eradication therapy, with P. aeruginosa eradicated in 20 (77%) out of 26 following one eradication cycle and in three (total 88%) additional children following a second cycle. Eradication was associated with a significant decrease in neutrophil elastase and interleukin-1beta in BAL fluid 12 months post eradication. Eradication of Pseudomonas aeruginosa infection is achievable in young children with cystic fibrosis for up to 5 yrs using combination i.v., oral and nebulised antibiotic therapy and is associated with reduced pulmonary inflammation 12 months post eradication.

Discovery and optimization of triazolopyridazines as potent and selective inhibitors of the c-Met kinase

Tumorigenesis is a multistep process in which oncogenes play a key role in tumor formation, growth, and maintenance. MET was discovered as an oncogene that is activated by its ligand, hepatocyte growth factor. Deregulated signaling in the c-Met pathway has been observed in multiple tumor types. Herein we report the discovery of potent and selective triazolopyridazine small molecules that inhibit c-Met activity.

Evaluation of a series of naphthamides as potent, orally active vascular endothelial growth factor receptor-2 tyrosine kinase inhibitors

We have previously shown N-arylnaphthamides can be potent inhibitors of vascular endothelial growth factor receptors (VEGFRs). N-Alkyl and N-unsubstituted naphthamides were prepared and found to yield nanomolar inhibitors of VEGFR-2 (KDR) with an improved selectivity profile against a panel of tyrosine and serine/threonine kinases. The inhibitory activity of this series was retained at the cellular level. Naphthamides 3, 20, and 22 exhibited good pharmacokinetics following oral dosing and showed potent inhibition of VEGF-induced angiogenesis in the rat corneal model. Once-daily oral administration of 22 for 14 days led to 85% inhibition of established HT29 colon cancer and Calu-6 lung cancer xenografts at doses of 10 and 20 mg/kg, respectively.

N-methylacetamide analog of salvinorin A: a highly potent and selective kappa-opioid receptor agonist with oral efficacy

Several preclinical studies indicate that selective kappa-opioid receptor (KOR) antagonists have antidepressant-like effects, whereas KOR agonists have opposite effects, suggesting that each might be useful in the treatment of mood abnormalities. Salvinorin A (salvA) is a valuable KOR agonist for further study due to its high potency and receptor selectivity. However, it has short lasting effects in vivo and limited oral bioavailability, probably due to acetate metabolism. We compared the in vitro receptor binding selectivity of salvA and four analogs containing an ethyl ether (EE), isopropylamine (IPA), N-methylacetamide (NMA), or N-methylpropionamide (NMP) at C-2. All compounds showed high binding affinity for the KOR (K(i) = 0.11-6.3 nM), although only salvA, EE, and NMA exhibited KOR selectivity. In a liver microsomal assay, salvA was least stable, whereas NMA and IPA displayed slower metabolic transformations. Intraperitoneal (i.p.) administration of salvA, NMA, and NMP dose-dependently elevated brain reward thresholds in the intracranial self-administration (ICSS) test, consistent with prodepressive-like KOR agonist effects. NMA and NMP were equipotent to salvA but displayed longer lasting effects (6- and 10-fold, respectively). A dose of salvA with prominent effects in the ICSS test after i.p. administration (2.0 mg/kg) was inactive after oral administration, whereas the same oral dose of NMA elevated ICSS thresholds. These studies suggest that, although salvA and NMA are similar in potency and selectivity as KOR agonists in vitro, NMA has improved stability and longer lasting actions that might make it more useful for studies of KOR agonist effects in animals and humans.

Blood-compatible biomaterials by surface coating with a novel antithrombin-heparin covalent complex

Covalent antithrombin-heparin complex (ATH) was covalently grafted to a polycarbonate urethane (Corethane) endoluminal graft (a kind gift of Corvita Corporation) after being activated using 0.3% m/m NaOCl in 0.15 M phosphate pH 6.0. ATH graft density (1.98 x 10(-7) mol/m2) was 6 times the maximum amount of unfractionated heparin (UFH) that could be bound to polycarbonate urethane surfaces. Surface-bound ATH could be stored in sterile 0.15 M NaCl at 4 degrees C for at least 2 months with good antithrombotic activity before being implanted into rabbits. Analysis of ATH-coated tubing showed that it contained significant direct thrombin inhibitory activity. In vivo testing in a rabbit model was compared to non-activated non-coated surfaces, activated-non-coated surfaces, hirudin-coated surfaces and antithrombin (AT)-coated surfaces. The weight of the clot generated in the ATH-coated graft tubing was significantly less than the weight of the clot generated within the hirudin-coated graft (p = 0.03 with a 1-tailed Student's t test). The anticoagulant nature of ATH grafts in vivo was shown to be due to bound ATH because boththe AT-coated surfaces and non-coated but activated surfaces showed similar thromboresistant efficacy to that of untreated material (ANOVA; p < 0.05). Apart from the direct antithrombin activity that contributed to much of the prolonged patency in vivo, surface-bound ATH likely catalyzed AT inhibition of thrombin, as evidenced by a significant number of 125I-AT binding sites (> or = 1.5 x 10(-8) mol/m2). Thus, ATH appears to be a good candidate for coating cardiovascular devices, such as endoluminal grafts, with high levels of substitution and significant long-term blood-compatibility.

Plasmodium falciparum signal sequences: simply sequences or special signals?

The malaria parasite, Plasmodium falciparum, synthesises and exports several proteins inducing morphological and biochemical modifications of erythrocytes during the erythrocytic cycle. The protein trafficking machinery of the parasite is similar to that of other eukaryotic cells in several ways. However, some unusual features are also observed. The secretion of various polypeptides was inhibited when P. falciparum-infected erythrocytes were incubated with Brefeldin A. Immunoelectron microscopy studies revealed substantial morphological changes in the endoplasmic reticulum following exposure of parasitised erythrocytes to the drug. Immunofluorescence studies of Brefeldin A-treated parasites suggest that polypeptide sorting to different intracellular destinations begins at the endoplasmic reticulum. The parasite also secretes polypeptides by a Brefeldin A-insensitive route that bypasses the classical endoplasmic reticulum-Golgi complex pathway.

In vitro and in vivo antimalarial activity of ferrochloroquine, a ferrocenyl analogue of chloroquine against chloroquine-resistant malaria parasites

Previous studies have shown that ferrochloroquine (FQ) exhibited an antimalarial activity against Plasmodium spp. The present work confirmed this activity, described the curative effect on P. vinckei and investigated the FQ toxicity in vitro and in vivo. The in vitro and in vivo growth inhibition of P. falciparum and P. berghei N, respectively, showed that FQ antimalarial activity was 1.5-10 times more potent than chloroquine. FQ completely inhibited the in vivo development of both chloroquine-susceptible and resistant P. vinckei strains and protected mice from lethal infection at a dose of 8.4 mg kg(-1) day(-1) given for 4 days subcutaneously or orally. This curative effect was 5-20 times more potent than chloroquine, according to the strains' resistance to chloroquine. At this curative dose, no clinical changes were observed in mice up to 14 days after the last administration. Nevertheless, the acute toxicity and lethality of ferrochloroquine seemed to be dependent on gastric surfeit. The FQ security index determined in vitro confirmed that it might be a promising compound.

Novel ferrocenic artemisinin derivatives: synthesis, in vitro antimalarial activity and affinity of binding with ferroprotoporphyrin IX

Following our search for novel compounds with high antimalarial activity, a series of artemisinin (QHS) derivatives containing a ferrocenic nucleus was prepared and tested in vitro against Plasmodium falciparum strains. Two new metallocenic derivatives (1 and 3) were found as potent as QHS. All compounds showed a capacity to bind with ferroprotoporphyrin IX. A decrease in the Soret band absorbance of ferroprotoporphyrin IX, resulting from the addition of different drugs concentrations, was shown. The association stoichiometry of compounds to ferroprotoporphyrin IX appears to be 1:2 at equilibrium, with an intermediate 1:1 complexation. These results appear to strengthen the role of adducts between artemisinin derivatives and heme in generation of artemisinin radicals. Such interaction of artemisinin ferrocenyl derivatives with ferroprotoporphyrin IX and its biological significance could form a basis in future drug development.

Pfsbp1, a Maurer's cleft Plasmodium falciparum protein, is associated with the erythrocyte skeleton

Antibodies from hyperimmune monkey sera, selected by absorption to Plasmodium falciparum-infected erythrocytes, and elution at acidic pH, allowed us to characterize a novel parasite protein, Pfsbp1 (P. falciparum skeleton binding protein 1). Pfsbp1 is an integral membrane protein of parasite-induced membranous structures associated with the erythrocyte plasma membrane and referred to as Maurer's clefts. The carboxy-terminal domain of Pfsbp1, exposed within the cytoplasm of the host cell, interacts with a 35 kDa erythrocyte skeletal protein and might participate in the binding of the Maurer's clefts to the erythrocyte submembrane skeleton. Antibodies to the carboxy- and amino-terminal domains of Pfsbp1 labelled similar vesicular structures in the cytoplasm of Plasmodium chabaudi and Plasmodium berghei-infected murine erythrocytes, suggesting that the protein is conserved among malaria species, consistent with an important role of Maurer's cleft-like structures in the intraerythrocytic development of malaria parasites.

Influence of exogenous factor VIIa on thrombin generation in cord plasma of full-term and pre-term newborns

Factor (F) VIIa has been used to treat adults and children with a variety of bleeding disorders. The results from these studies cannot be extrapolated to newborns because their hemostatic system differs significantly from adults, which may influence the effects of FVIIa on thrombin (IIa) generation. We compared the effects of FVIIa concentrates on IIa generation in plasmas from adults, full-term newborns and pre-term newborns. Defibrinated plasma (using arvin) from adults, or umbilical cords from full-term or pre-term deliveries was supplemented with FVIIa (Novo Nordisk, Bagsvaerd, Denmark), mixed with dilute thromboplastin reagent, and the resultant reaction mixture subsampled periodically into ethylenediamine tetraacetic acid, followed by measurement of total IIa activity (S-2238). Thrombin-alpha2 macroglobulin complexes, determined as residual activity after neutralization with heparin and antithrombin, were subtracted from total IIa to give free IIa. Prothrombin (FII) and inhibitor complexes were measured by enzyme-linked immunosorbent assays. Addition of FVIIa caused a reduction in the lag phase for the appearance of free IIa and consumption of FII, which was more pronounced in newborn plasma. There was no increase in peak IIa levels regardless of the amount of FVIIa added. Final inhibitor complex concentrations were increased in plasmas from adults compared with newborns, likely reflecting higher plasma concentrations of FII in adults. Generation of IIa was more rapid in pre-term plasma compared with that in adult and full-term cord plasmas due to increased endogenous tissue factor (TF). In summary, FVIIa enhanced IIa generation in plasma from different age groups, with the effect being more pronounced in plasma from pre-term newborns, possibly due to increased levels of plasma TF.