Publications by authors named "Joanna Webb"

Objective: Bearded dragons (Pogona vitticeps), a popular zoological companion species, frequently require sedation for procedures. A novel formulation of alfaxalone with preservatives was FDA approved for 28-day use after the vial is breached. Research has been performed in squamate species using alfaxalone without preservatives at various doses and routes of administration, but it is unknown whether preservatives affect quality of sedation or cardiac function.

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Case Description: A 12-year-old sexually intact male zoo-managed Sumatran tiger (Panthera tigris sumatrae) was evaluated for a 3-day history of vomiting, hyporexia, and lethargy. Radiographs were supportive of gastrointestinal obstruction, and an exploratory laparotomy was performed.

Clinical Findings: Diffuse tan foci were present on the liver parenchyma, and the tiger became icteric throughout the procedure.

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North American vipers are commonly housed in zoological institutions or studied as free-ranging populations. Because of their venomous predatory and defensive mechanism, sedation or anesthesia is frequently employed to facilitate safe handling and medical procedures, especially of the head. A new formulation of alfaxalone with proprietary preservatives was recently approved and indexed for 28-d use post-vial puncture.

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Pododermatitis is an important cause of morbidity and mortality in flamingos under human care; management and treatment options vary widely based on subjective assessment from veterinarians or animal care staff (ACS). The objective of this study was to evaluate the agreement of pododermatitis severity scores assigned by veterinarians, ACS, and veterinary students when given a standardized rubric. Twenty-four greater flamingos () from a single zoo-managed flock were evaluated over time for pododermatitis.

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Microbial resistance to antibiotics is a serious global health problem compounded by antibiotic overuse and limited investment in new antibiotic research. Inappropriate perinatal antibiotic exposure is increasingly linked to lifelong adverse outcomes through its impact on the developing microbiome. Antibiotic stewardship may be the only effective preventative strategy currently available.

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CASE DESCRIPTION 3 ferrets (Mustela putorius furo), aged 1 to 2 years, were referred for evaluation of a 4-day to 2-week history of gastrointestinal signs, including anorexia, regurgitation, and vomiting. CLINICAL FINDINGS All 3 ferrets had clinical signs suggestive of dysphagia or esophagitis on initial examination. Esophagoscopy, barium-contrast esophagography, or both revealed foreign bodies with mucosal inflammation in 1 patient and an esophageal foreign body with stricture in 2 patients.

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Net reductive elimination (RE) of MeX (X = halide or pseudo-halide: Cl(-), CF3CO2(-), HSO4(-), OH(-)) is an important step during Pt-catalyzed hydrocarbon functionalization. Developing Rh(I/III)-based catalysts for alkane functionalization is an attractive alternative to Pt-based systems, but very few examples of RE of alkyl halides and/or pseudo-halides from Rh(III) complexes have been reported. Here, we compare the influence of the ligand donor strength on the thermodynamic potentials for oxidative addition and reductive functionalization using [(t)Bu3terpy]RhCl (1) {(t)Bu3terpy = 4,4',4''-tri-tert-butylpyridine} and [(NO2)3terpy]RhCl (2) {(NO2)3terpy = 4,4',4''-trinitroterpyridine}.

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The controlled conversion of hydrocarbons to functionalized products requires selective C-H bond cleavage. This perspective provides an overview of 1,2-CH-addition of hydrocarbons across d(0) transition metal imido complexes and compares and contrasts these to examples of analogous reactions that involve later transition metal amide, hydroxide and alkoxide complexes with d(6) and d(8) metals.

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Metal-mediated formation of C-O bonds is an important transformation that can occur by a variety of mechanisms. Recent studies suggest that oxygen-atom insertion into metal-hydrocarbyl bonds in a reaction that resembles the Baeyer-Villiger transformation is a viable process. In an effort to identify promising new systems, this study is designed to assess the impact of metal identity on such O-atom insertions for the reaction [(bpy)(x)M(Me)(OOH)](n) → [(bpy)(x)M(OMe)(OH)](n) (x = 1 or 2; bpy = 2,2'-bipyridyl; n is varied to maintain the d-electron count at d(6) or d(8)).

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The Pt(II) amido and phenoxide complexes ((t)bpy)Pt(Me)(X), ((t)bpy)Pt(X)(2), and [((t)bpy)Pt(X)(py)][BAr'(4)] (X = NHPh, OPh; py = pyridine) have been synthesized and characterized. To test the feasibility of accessing Pt(IV) complexes by oxidizing their Pt(II) precursors, the previously reported ((t)bpy)Pt(R)(2) (R = Me and Ph) systems were oxidized with I(2) to yield ((t)bpy)Pt(R)(2)(I)(2). The analogous reaction with ((t)bpy)Pt(Me)(NHPh) and MeI yields the corresponding ((t)bpy)Pt(Me)(2)(NHPh)(I) complex.

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Synthesis and characterization of the monomeric complex ((t)bpy)Pt(Me)(NHPh) ((t)bpy = 4,4'-di-tert-butyl-2,2'-dipyridyl) has been accomplished. Mechanistic studies reveal that 1,2-addition of dihydrogen across the Pt-anilido bond to initially produce ((t)bpy)Pt(Me)(H) and free aniline is catalyzed by elemental Pt rather than through a pathway that involves direct activation of H(2) by Pt and 1,2-addition across the Pt-NHPh bond.

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Vitamin K-dependent protein S and complement regulator C4b-binding protein (C4BP) form a high-affinity complex in plasma. We have previously shown that both free protein S and the C4BP-protein S complex can bind to apoptotic Jurkat cells. It has been demonstrated in the past that protein S and C4BP can bind to neutrophils.

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Complement regulator C4b-binding protein (C4BP) and the anticoagulant vitamin K-dependent protein S form a high affinity complex in human plasma. C4BP is composed of seven alpha-chains and a unique beta-chain, each chain comprising repeating complement control protein (CCP) modules. The binding site for protein S mainly involves the first of the three beta-chain CCPs (CCP1).

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Apoptosis is characterized by a lack of inflammatory reaction in surrounding tissues, suggesting local control of complement activation. During the initial stage of apoptosis, cells expose negatively charged phospholipid phosphatidylserine on their surfaces. The vitamin K-dependent protein S has a high affinity for this type of phospholipid.

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