Dural arteriovenous fistula causing reversible cognitive impairment.

A previously independent 82-year-old woman presented with 5 months of worsening confusion, mobility and cognitive decline, with deficits in orientation, language and executive function. A cerebral dural arteriovenous fistula was identified and successfully embolised, after which her cognitive ability and independence dramatically improved. Although rare, a dural arteriovenous fistula may mimic a rapidly progressive dementia, but its early recognition and treatment can completely reverse the dementia.

A blinded, randomized, placebo-controlled, dose determination trial of lokivetmab (ZTS-00103289), a caninized, anti-canine IL-31 monoclonal antibody in client owned dogs with atopic dermatitis.

BACKGROUND: Pruritus is the hallmark clinical sign of atopic dermatitis (AD) in dogs. Lokivetmab, a caninized anti-canine IL-31 monoclonal antibody, reduced pruritus and associated inflammatory skin lesions in a proof-of-concept study in dogs with AD. HYPOTHESIS/OBJECTIVES: The objective was to describe lokivetmab dose response in a randomized, double blind, placebo-controlled trial. ANIMALS: Clinicians at 15 referral clinics enrolled 211 client owned dogs with a history of chronic AD. METHODS: Dogs were randomized to treatment with lokivetmab (0.125, 0.5 or 2.0 mg/kg) or placebo administered subcutaneously once on Day 0. Dog owners assessed visual analog scale (VAS) scores of pruritus on days 0, 1, 2, 3, 7, 14, 21, 28, 35, 42, 49 and 56. Clinicians assessed Canine AD Extent and Severity Index (CADESI-03) scores on days 0, 7, 14, 28, 42 and 56. RESULTS: Treatment with lokivetmab (2 mg/kg) resulted in a greater percentage reduction from baseline in owner assessed pruritus (days 1-49) and clinician assessed CADESI-03 scores (days 7-56) compared to placebo (P < 0.05); differences were achieved in lower dose groups but at later time points and for shorter duration for both owner assessed pruritus (0.5 mg/kg, days 2-35; 0.125 mg/kg, days 7-21) and clinician assessed CADESI-03 scores (0.5 mg/kg and 0.125 mg/kg, Day 14). CONCLUSIONS AND CLINICAL IMPORTANCE: Lokivetmab (0.5, 2.0 mg/kg) reduced pruritus compared to placebo for at least 1 month. Level and duration of response increased with increasing dose. Further studies are needed to better understand variability in individual responses across a broader population of dogs with AD.

High Prevalence of New Clinically Significant Findings in Patients With Embolic Stroke of Unknown Source Evaluated by Cardiac Magnetic Resonance Imaging.

BACKGROUND: Embolic stroke of unknown source (ESUS) accounts for 1 in 6 ischemic strokes. Current guidelines do not recommend routine cardiac magnetic resonance (CMR) imaging in ESUS, and beyond the identification of cardioembolic sources, there are no data assessing new clinical findings from CMR in ESUS. This study aimed to assess the prevalence of new cardiac and noncardiac findings and to determine their impact on clinical care in patients with ESUS. METHODS AND RESULTS: In this prospective, multicenter, observational study, CMR imaging was performed within 3 months of ESUS. All scans were reported according to standard clinical practice. A new clinical finding was defined as one not previously identified through prior clinical evaluation. A clinically significant finding was defined as one resulting in further investigation, follow-up, or treatment. A change in patient care was defined as initiation of medical, interventional, surgical, or palliative care. From 102 patients recruited, 96 underwent CMR imaging. One or more new clinical findings were observed in 59 patients (61%). New findings were clinically significant in 48 (81%) of these patients. Of 40 patients with a new clinically significant cardiac finding, 21 (53%) experienced a change in care (medical therapy, n=15; interventional/surgical procedure, n=6). In 12 patients with a new clinically significant extracardiac finding, 6 (50%) experienced a change in care (medical therapy, n=4; palliative care, n=2). CONCLUSIONS: CMR imaging identifies new clinically significant cardiac and noncardiac findings in half of patients with recent ESUS. Advanced cardiovascular screening should be considered in patients with ESUS. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04555538.

Halting metastasis through CXCR4 inhibition.

Metastasis occurs when cancer cells leave the primary tumor site and migrate to distant parts of the body. The CXCR4-SDF-1 pathway facilitates this migration, and its expression has become the hallmark of several metastatic cancers. Targeted approaches are currently being developed to inhibit this pathway, and several candidates are now in clinical trials. Continued exploration of CXCR4 inhibitors will generate compounds that have improved activity over current candidates.

Psammaplysin F: a unique inhibitor of bacterial chromosomal partitioning.

Described is the antibiotic activity of a marine natural product. Psammaplysin F (1) inhibited the growth of four Gram-positive strains by >80% at 50µM, and the amine at position C-20 is responsible for the observed antibacterial activity. When tested against two strains of methicillin resistant Staphylococcus aureus (MRSA), the minimum inhibitory concentrations (MICs) for psammaplysin F (40-80µM) were similar to the structurally-related alkaloid psammaplysin H (2). Psammaplysin F (1) increased membrane permeability by two to four-fold compared to psammaplysin H (2) or control-treated bacteria, respectively. Unlike psammaplysin H (2), we show that psammaplysin F (1) inhibits equal partitioning of DNA into each daughter cell, suggesting that this natural product is a unique prokaryotic cell division inhibitor.

A potential rhodium cancer therapy: studies of a cytotoxic organorhodium(I) complex that binds DNA.

Described is a novel organorhodium(I) complex that is cytotoxic to the colon cancer cell line HCT116 and alters cell migration, DNA replication, and DNA condensation. Most importantly, the mechanism observed is not seen for the parent organorhodium dimer complex [{RhCl(COD)}2], RhCl3, or the free ligand/proligands (COD and 1-(n)butyl-3-methylimidazolium chloride). Thus, the activity of this organorhodium complex is attributable to its unique structure.

Synthesis, structure-activity analysis, and biological evaluation of sanguinamide B analogues.

We report the first synthesis of sanguinamide B analogues. Substituting N-methylated (N-Me) amino acids, glycine (Gly), and L- or D-phenylalanine (Phe) into the backbone of sanguinamide B showed that only l- and d-Phe residues controlled the macrocycle conformation. The N-methylated and glycine analogues all had multiple conformations, whereas the L- and D-Phe derivatives only had a single conformation. Testing of all conformer analogues showed that inclusion of an L- or D-Phe was a superior design element than incorporating the N-Me moiety that is often utilized to control macrocyclic conformation. Finally, we show that there is an ideal Phe residue (in this case L-Phe) for generating compounds that have the greatest inhibitory effect on bacterial motility. Our data support the hypothesis that the macrocyclic conformation is dictated by the benzyl moiety requiring a "pseudoequatorial" position, and all other energy considerations are secondary.

An Hsp90 modulator that exhibits a unique mechanistic profile.

Described is the synthesis of two biotinylated derivatives of a cytotoxic macrocycle. Pull-down assays indicate that this macrocycle targets the N-middle domain of Hsp90. Untagged compound can effectively compete away tagged compound-Hsp90 protein complexes, confirming the binding specificity of the macrocycle for Hsp90. The macrocycle is similar in potency to other structurally-related analogs of Sansalvamide A (San A) and induces apoptosis via a caspase 3 mechanism. Unlike other San A derivatives, we show that the macrocycle does not inhibit binding between C-terminal client proteins and co-chaperones and Hsp90, suggesting that it has a unique mechanism of action.

AmrZ beta-sheet residues are essential for DNA binding and transcriptional control of Pseudomonas aeruginosa virulence genes.

AmrZ is a putative ribbon-helix-helix (RHH) transcriptional regulator. RHH proteins utilize residues within the ß-sheet for DNA binding, while the α-helices promote oligomerization. AmrZ is of interest due to its dual roles as a transcriptional activator and as a repressor, regulating genes encoding virulence factors associated with both chronic and acute Pseudomonas aeruginosa infection. In this study, cross-linking revealed that AmrZ forms oligomers in solution but that the amino terminus, containing an unordered region and a ß-sheet, were not required for oligomerization. The first 12 unordered residues (extended amino terminus) contributed minimally to DNA binding. Mutagenesis of the AmrZ ß-sheet demonstrated that residues 18, 20, and 22 were essential for DNA binding at both activation and repressor sites, suggesting that AmrZ utilizes a similar mechanism for binding to these sites. Mice infected with amrZ mutants exhibited reduced bacterial burden, morbidity, and mortality. Direct in vivo competition assays showed a 5-fold competitive advantage for the wild type over an isogenic amrZ mutant. Finally, the reduced infection phenotype of the amrZ-null strain was similar to that of a strain expressing a DNA-binding-deficient AmrZ variant, indicating that DNA binding and transcriptional regulation by AmrZ is responsible for the in vivo virulence defect. These recent infection data, along with previously identified AmrZ-regulated virulence factors, suggest the necessity of AmrZ transcriptional regulation for optimal virulence during acute infection.

Efficacy of sublingual administration of detomidine gel for sedation of horses undergoing veterinary and husbandry procedures under field conditions.

OBJECTIVE: To determine whether sublingual detomidine gel administration to horses would be effective in providing an appropriate degree of sedation and restraint to facilitate completion of veterinary and husbandry procedures under field conditions. DESIGN: Multicenter, prospective, randomized, blinded, placebo-controlled clinical study. ANIMALS: 270 client-owned horses known to require sedation or strong restraint to enable veterinary and husbandry procedures to be performed. PROCEDURES: Horses randomly received a single dose of detomidine gel (0.04 mg/kg [0.018 mg/lb]) or placebo gel administered sublingually. Horses were sedated to facilitate cleaning the prepuce, cutting of hair with electric clippers, hoof trimming or application of shoes, manual dental floating (ie, rasping or filing of the teeth to remove irregularities), nasogastric passage of a stomach tube or endoscope, and radiography. The primary determinant of efficacy was an assessment by a veterinarian on the ability or inability to successfully conduct the procedure. RESULTS: 171 horses met all the study protocol criteria. One hundred twenty-nine horses were treated with detomidine. The procedure was completed successfully for 76% (98/129) of the detomidine-treated horses, while the procedure was completed successfully for only 7% (3/42) of the placebo-treated horses. The percentage of horses in which the procedure was successfully completed was significantly different between detomidine-treated horses and placebo-treated horses. No serious adverse effects were reported. CONCLUSIONS AND CLINICAL RELEVANCE: Detomidine gel administered to horses sublingually at a dose of 0.04 mg/kg provided an appropriate degree of sedation and restraint to facilitate completion of veterinary and husbandry procedures in horses known to require sedation for such procedures.

Nanoparticles for Bioapplications: Study of the Cytotoxicity of Water Dispersible CdSe(S) and CdSe(S)/ZnO Quantum Dots.

Semiconductor nanocrystals or quantum dots (QDs) have unique optical and physical properties that make them potential imaging tools in biological and medical applications. However, concerns over the aqueous dispersivity, toxicity to cells, and stability in biological environments may limit the use of QDs in such applications. Here, we report an investigation into the cytotoxicity of aqueously dispersed CdSe(S) and CdSe(S)/ZnO core/shell QDs in the presence of human colorectal carcinoma cells (HCT-116) and a human skin fibroblast cell line (WS1). The cytotoxicity of the precursor solutions used in the synthesis of the CdSe(S) QDs was also determined in the presence of HCT-116 cells. CdSe(S) QDs were found to have a low toxicity at concentrations up to 100 µg/mL, with a decreased cell viability at higher concentrations, indicating a highly dose-dependent response. Meanwhile, CdSe(S)/ZnO core/shell QDs exhibited lower toxicity than uncoated QDs at higher concentrations. Confocal microscopy images of HCT-116 cells after incubation with CdSe(S) and CdSe(S)/ZnO QDs showed that the cells were stable in aqueous concentrations of 100 µg of QDs per mL, with no sign of cell necrosis, confirming the cytotoxicity data.

ProHeart® 12, a moxidectin extended-release injectable formulation for prevention of heartworm (Dirofilaria immitis) disease in dogs in the USA for 12 months.

BACKGROUND: The efficacy of an extended-release injectable moxidectin (0.5 mg/kg) suspension (ProHeart® 12) (PH 12) in preventing the development of Dirofilaria immitis in dogs for 12 months was investigated in laboratory and field studies in the USA. METHODS: In each of two laboratory studies, 20 dogs ≥ 12 months of age were randomly allocated to receive a subcutaneous injection of saline or PH 12 on Day 0 and were then inoculated with 50 D. immitis third-stage larvae (L3) on Day 365. All dogs were necropsied ~ 5 months post-inoculation for adult worm counts. The field efficacy study included dogs ≥ 10 months of age from 19 veterinary clinics in the USA treated with either 20 monthly doses of Heartgard® Plus (HG Plus) (296 dogs) or two doses of PH 12 (297 dogs) on Days 0 and 365. Efficacy was determined on Days 365, 480 and 605 using adult HW antigen and microfilaria testing to assess adult HW infection. RESULTS: PH 12 was 100% effective in preventing HW disease in all three of these studies. In the laboratory studies, no PH 12-treated dogs had any adult HWs, whereas all control dogs in both studies had adult HWs [geometric mean, 30.2 (range, 22-37) for Study 1 and 32.6 (22-44) for Study 2]. In the field study, all dogs treated with PH 12 tested negative for adult HW infection on all test days (Days, 365, 480 and 605), whereas four dogs receiving HG Plus (positive control) tested positive for HWs during the study (three dogs on Day 365 and one dog on Day 480). All four dogs treated with HG Plus that subsequently tested positive for HWs during the field study were from the lower Mississippi River Valley region, where HW resistance to macrocyclic lactone preventives has been confirmed to occur. PH 12 was significantly better than HG Plus in preventing heartworm disease in the field study (P = 0.0367). PH 12 was well-tolerated in both laboratory and field studies. CONCLUSIONS: A single dose of ProHeart® 12 was 100% effective in preventing heartworm disease in dogs for a full year in both laboratory and field studies.

Evaluation of two antimicrobial therapies in the treatment of Leptospira borgpetersenii serovar hardjo infection in experimentally infected cattle.

This study demonstrated the ability of the antimicrobials tulathromycin (Draxxin) and ceftiofur crystalline free acid sterile suspension (Excede) to clear the spirochete Leptospira borgpetersenii serovar hardjo type hardjo-bovis (L. hardjo-bovis) from experimentally infected cattle. Treatment with tulathromycin resulted in clearance of L. hardjo-bovis organisms from the urine and kidney tissue of all animals (9 of 9), and treatment with ceftiofur crystalline free acid resulted in clearance of the organisms from the urine of 8 of 10 heifers and the kidney tissue of all 10 animals. In contrast, 10 of 10 placebo-treated cattle had L. hardjo-bovis organisms in their urine and 8 of 10 had the organisms in kidney tissue.

Can pulse oximetry or a bedside swallowing assessment be used to detect aspiration after stroke?

BACKGROUND AND PURPOSE: Desaturation during swallowing may help to identify aspiration in stroke patients. This study investigated pulse oximetry, bedside swallowing assessment (BSA), and videofluoroscopy as tests for detecting aspiration after stroke. METHODS: Swallowing was assessed in 189 stroke patients (mean+/-SD age, 70.9+/-12.3 years) within 5 days of symptom onset with a modified BSA (water replaced by radio-opaque contrast agent, followed by chest radiography to detect aspiration). Simultaneous pulse oximetry recorded the greatest desaturation from baseline for 10 minutes from modified BSA onset. Videofluoroscopy was undertaken in 54 (28%) patients. RESULTS: Modified BSA showed a safe swallow in 98 (51.9%), unsafe swallow in 85 (45.0%), and silent aspiration in 6 (3.2%) patients. During swallowing, desaturation by >2% occurred in 27 (27.6%) and by >5% in 3 (3.1%) of the 98 safe-swallow patients on modified BSA. Of the 85 unsafe-swallow patients, only 28 (32.9%) desaturated by >2% and 6 (7.1%) by >5%. Desaturation did not occur in any of the 6 silent aspirators. With the modified BSA to detect aspiration, sensitivity and specificity, respectively, were 0.31 and 0.72 for desaturation >2% and 0.07 and 0.97 for desaturation >5%. By videofluoroscopy, sensitivity and specificity for detecting aspiration were 0.47 and 0.72 for modified BSA, 0.33 and 0.62 for desaturation >2%, and 0.13 and 0.95 for desaturation >5%. Combining a failed modified BSA with desaturation >2% or >5% did not significantly improve predictive values. CONCLUSIONS: Modified BSA and pulse oximetry during swallowing, whether alone or in combination, showed inadequate sensitivity, specificity, and predictive values for detection of aspiration compared with videofluoroscopy in stroke patients.

Hydrothermal synthesis of highly luminescent blue-emitting ZnSe(S) quantum dots exhibiting low toxicity.

Highly luminescent quantum dots (QDs) that emit in the visible spectrum are of interest to a number of imaging technologies, not least that of biological samples. One issue that hinders the application of luminescent markers in biology is the potential toxicity of the fluorophore. Here we show that hydrothermally synthesized ZnSe(S) QDs have low cytotoxicity to both human colorectal carcinoma cells (HCT-116) and human skin fibroblast cells (WS1). The QDs exhibited a high degree of crystallinity, with a strong blue photoluminescence at up to 29% quantum yield relative to 4',6-diamidino-2-phenylindole (DAPI) without post-synthetic UV-irradiation. Confocal microscopy images obtained of HCT-116 cells after incubation with the QDs highlighted the stability of the particles in cell media. Cytotoxicity studies showed that both HCT-116 and WS1 cells retain 100% viability after treatment with the QDs at concentrations up to 0.5g/L, which makes them of potential use in biological imaging applications.

The Pseudomonas aeruginosa AmrZ C-terminal domain mediates tetramerization and is required for its activator and repressor functions.

Pseudomonas aeruginosa is an important bacterial opportunistic pathogen, presenting a significant threat towards individuals with underlying diseases such as cystic fibrosis. The transcription factor AmrZ regulates expression of multiple P. aeruginosa virulence factors. AmrZ belongs to the ribbon-helix-helix protein superfamily, in which many members function as dimers, yet others form higher order oligomers. In this study, four independent approaches were undertaken and demonstrated that the primary AmrZ form in solution is tetrameric. Deletion of the AmrZ C-terminal domain leads to loss of tetramerization and reduced DNA binding to both activated and repressed target promoters. Additionally, the C-terminal domain is essential for efficient AmrZ-mediated activation and repression of its targets.

Early assessments of dysphagia and aspiration risk in acute stroke patients.

BACKGROUND AND PURPOSE: Dysphagia is common after stroke and is a marker of poor prognosis. Early identification is important. This article reviews the merits and limitations of various assessment methods available to clinicians. METHODS: An electronic database search was performed of MEDLINE, EMBASE, and the Cochrane database using such terms as stroke, aspiration, dysphagia, and assessment; extensive manual searching of articles was also conducted. RESULTS: Bedside tests are safe, relatively straightforward, and easily repeated but have variable sensitivity (42% to 92%), specificity (59% to 91%), and interrater reliability (kappa=0 to 1.0). They are also poor at detecting silent aspiration. Videofluoroscopy gives anatomic and functional information and allows testing of therapeutic techniques. However, swallowing is assessed under ideal conditions that are different from clinical settings, and reliability is often poor (kappa=0 to 0.75) in the absence of assessor training. Fiberoptic endoscopy allows swallow assessment and sensory testing but requires specialized staff and equipment. Oxygen desaturation during swallowing may be predictive of aspiration (sensitivity, 73% to 87%; specificity, 39% to 87%) but is more useful in combination with bedside testing than in isolation. Other methods of swallow testing are invasive and require specialized staff and equipment. CONCLUSIONS: Although bedside tests remain an important early screening tool for dysphagia and aspiration risk, further refinements are needed to improve their accuracy.

Mechanistic studies of sanguinamide B derivatives: a unique inhibitor of eukaryotic ribosomes.

Described are mechanistic studies of two Sanguinamide B (San B) derivatives. These compounds were identified as eukaryotic ribosomal inhibitors. Two biotinylated San B derivatives were synthesized and used to capture protein targets in a pull-down assay. LC/MS/MS analysis of the San B-captured targets identified several proteins that comprise eukaryotic ribosomal subunits. The translation inhibitory effect of San B was confirmed using an in vitro translation assay. Moreover, an evaluation of cell death mechanisms is reported.

Effectively delivering a unique hsp90 inhibitor using star polymers.

We report the synthesis of a novel heat shock protein 90 (hsp90) inhibitor conjugated to a star polymer. Using reversible addition-fragmentation chain-transfer (RAFT) polymerization, we prepared star polymers comprised of PEG attached to a predesigned functional core. The stars were cross-linked using disulfide linkers, and a tagged version of our hsp90 inhibitor was conjugated to the polymer core to generate nanoparticles (14 nM). Dynamic light scattering showed that the nanoparticles were stable in cell growth media for 5 days, and HPLC analysis of compound-release at 3 different pH values showed that release was pH dependent. Cell cytotoxicity studies and confocal microscopy verify that our hsp90 inhibitor was delivered to cells using this nanoparticle delivery system. Further, delivery of our hsp90 inhibitor using star polymer induces apoptosis by a caspase 3-dependent pathway. These studies show that we can deliver our hsp90 inhibitor effectively using star polymers, and induce apoptosis by the same pathway as the parent compound.

Simultaneous bone marrow and composite tissue transplantation in rats treated with nonmyeloablative conditioning promotes tolerance.

BACKGROUND: Approaches to safely induce tolerance in vascularized composite allotransplantation (VCA) with chimerism through bone marrow transplantation (BMT) are currently being pursued. However, VCA was historically performed sequentially after donor chimerism was established. Delayed VCA is not clinically applicable due to the time constraints associated with procurement from deceased donors. A more clinically relevant approach to perform both BMT and VCA simultaneously was evaluated. METHODS: Wistar Furth (RT1A) rats were treated with a short course of immunosuppressive therapy (anti-αß-TCR monoclonal antibody, FK-506, and anti-lymphocyte serum). One day before BMT, rats were treated with varying doses of total body irradiation (TBI) followed by transplantation of heterotopic osteomyocutaneous flaps from hindlimbs of August Copenhagen Irish (RT1A) rats. RESULTS: Eighty percent of rats conditioned with 300 cGy TBI and 40% of rats receiving 400 cGy TBI accepted the VCA. Mixed chimerism was detected in peripheral blood at 1 month after VCA, but chimerism was lost in all transplant recipients by 4 months. Most peripheral donor cells originated from the BMT and not from the VCA. Acceptors of VCA were tolerant of a donor skin graft challenge and no anti-donor antibodies were detectable, suggesting a central deletional mechanism for tolerance. Regulatory T cells (Treg) from spleens of acceptors more potently suppressed lymphocyte proliferation than Treg from rejectors in the presence of donor stimulator cells. CONCLUSIONS: These studies suggest that simultaneous BMT and VCA may establish indefinite allograft survival in rats through Treg-mediated suppression and thymic deletion of alloreactive T cells.