Placement, management and complications associated with peripheral intravenous catheter use in UK small animal practice.

OBJECTIVES: To describe the techniques for preparation and placement of peripheral intravenous catheters (PIVCs), to describe the complications associated with PIVCs, and to identify factors associated with PIVC complications in small animal practice in the United Kingdom. MATERIALS AND METHODS: A prospective multicentre observational study was undertaken between January 2022 and January 2023. Data collected included patient information, information regarding the placement and maintenance of PIVCs, and PIVC complications, from privately owned cats and dogs presenting to veterinary institutes in the United Kingdom. Patients required a PIVC to be placed as part of their care and the PIVC was anticipated to be in situ for >24 hours to be eligible for PIVC complication analysis. RESULTS: A total of 19 institutes recorded data regarding 382 PIVCs, with 325 (85.1%) placed in dogs and 57 (14.9%) in cats. The most common reasons for placement were to administer intravenous fluid therapy (74.3%) and intravenous medications (71.7%). There were 102 of 382 (26.7%) PIVCs associated with a complication, with limb swelling/suspected phlebitis in 44 of 382 (11.5%) and PIVC dislodgement/patient interference in 30 of 382 (7.9%) PIVCs. Factors associated with increased risk of complication were more than 1 attempt to place the PIVC, a second or subsequent PIVC being placed during hospitalisation, flush frequency different than every 1 to 24 hours, and flush solution with compound sodium lactate. CLINICAL SIGNIFICANCE: Veterinary professionals must be vigilant when monitoring a patient with a PIVC in situ, particularly if a PIVC is associated with one of the aforementioned factors of increased likelihood of complication.

Effects of Linear Periodization Training on Performance Gains and Injury Prevention in a Garrisoned Military Unit.

PURPOSE: Performing well in combat requires military service members to be in peak physical shape. Although each branch of the United States military has fitness guidelines and assessments, there are no exact prescriptions for physical training programs. The absence of a standardised approach may lead to suboptimal physical performance and increased risk of musculoskeletal injury. To address this gap, we evaluated the feasibility of a pilot combat conditioning program based on linear periodisation. METHODS: Twenty-nine garrisoned US Marine Corps service members (25 men, 4 women; 23.5±4.4 years) enrolled in our 11-week conditioning program that was supervised by a strength and conditioning professional. Military-specific (physical/combat fitness tests) and general (treadmill-based maximal exercise test) assessments were performed at baseline and 11 weeks. Training and injury logs were maintained throughout the duration of the program. RESULTS: Approximately 80% (23/29) of service members completed the entire program. Cardiorespiratory fitness (Peak VO2; +8.10±10.9%; p=0.011), upper-body strength (pull-ups; +47.0±58.2%; p<0.001) and core strength (abdominal crunches; +9.2±23.3%; p=0.029) significantly increased from pre- to post-training. No statistically significant improvement or worsening was noted in any other performance assessment measure. Eight (28%) participants reported minor musculoskeletal concerns, of which only one required medical attention (injury rate 1.3 injuries/100 person-months). CONCLUSION: A protocolised linear periodisation training program was feasible and demonstrated improvements in fitness in a group of garrisoned Marines with low injury rates. Other military units may benefit from a similar approach.

The ying and yang of idebenone: Not too little, not too much - cell death in NQO1 deficient cells and the mouse retina.

Idebenone has recently been investigated as a drug therapy for Leber's hereditary optic neuropathy (LHON), a rare genetic mitochondrial disease that causes rapid and progressive bilateral vision loss. Although several studies have shown that idebenone can promote vision recovery in patients with LHON, the evidence for the efficacy of idebenone is still limited. Idebenone failed to demonstrate superiority over placebo in the primary end-points of the only published randomised, double-blind, placebo-controlled trial. There appears to be a patient-specific response to idebenone with high variability in therapeutic outcomes. A recent study suggested that the cytosolic enzyme NAD(P)H: quinone acceptor oxidoreductase (NQO1) is the major enzyme involved in the activation of idebenone, and the beneficial effects of idebenone are dependent on the expression of NQO1. Here, we confirm the NQO1-dependent activity of idebenone, but we also show, for the first time, that the cytotoxicity of idebenone is linked to cellular expression of NQO1. Upon idebenone administration, cells deficient in NQO1 show a marked decrease in viability in comparison to NQO1 expressing cells, with idebenone causing ROS production and deleterious effects on ATP levels and cell viability. In addition, our data highlights that only cells expressing NQO1 can significantly activate idebenone, indicating that other proposed metabolic activation pathways, such as complex II and glycerol-3-phosphate dehydrogenase, do not play a significant role in idebenone activation. Furthermore, we provide evidence of idebenone-induced toxicity in the retina ex-vivo, which can be explained by the variation of NQO1 expression between different cell types in the mouse retina. Idebenone mediated cell rescue in the rotenone ex vivo model also indicated that this drug has a narrow therapeutic window. These findings will help to guide the development of future therapies and drug delivery strategies including intra-ocular administration. The specific dependence of idebenone activity on NQO1 may also explain the variation in patient outcomes in clinical trials.

Comparison of the laryngoscopy views with the size 1 Miller and Macintosh laryngoscope blades lifting the epiglottis or the base of the tongue in infants and children <2 yr of age.

BACKGROUND: Miller laryngoscope blades are preferred for laryngoscopy in infants and children <2 yr of age. Despite their long history, the laryngeal view with the Miller blade size 1 has never been compared with that with the Macintosh (MAC) blade in children. This prospective, single-blinded, randomized study was designed to compare the laryngeal views with the size 1 Miller and MAC blades in children <2 yr. METHODS: With IRB approval, 50 ASA I and II children <2 yr undergoing elective surgery were enrolled. After an inhalation induction and neuromuscular block with i.v. rocuronium 0.5 mg kg(-1), two laryngeal views were obtained with a single blade (Miller or MAC) in each child: one lifting the epiglottis and another lifting the tongue base. The best laryngeal views in each blade position were photographed with a SONY(®) Cyber-shot camera and rated by a blinded anaesthesiologist using the percentage of glottic opening scale. RESULTS: The scores with the Miller blade lifting the epiglottis and the MAC blade lifting the tongue base were similar. The scores with the Miller blade lifting the epiglottis and the tongue base were similar. The scores for the MAC blade lifting the tongue base were greater than those lifting the epiglottis (95% confidence interval: 7.6-26.8) (P=0.0004). CONCLUSIONS: In infants and children <2 yr of age, optimal laryngeal views may be obtained with either the Miller size 1 blade lifting the epiglottis or with the Miller or MAC blades lifting the tongue base. CLINICAL TRIAL REGISTRATION: NCT01717872 at Clinical Trials.gov.

Segregation effects on the properties of (AuAg)147.

AuAg nanoclusters are promising supported co-catalysts for photocatalytic hydrogen reduction. However, beyond the quantum regime (N > 100) little is known about how the electronic properties of these nanoparticles are affected by chemical ordering. We investigate the effects of chemical ordering on the properties of 147-atom cuboctahedral AuAg nanoclusters, using empirical potentials coupled with an atomic-swap basin-hopping search to optimise the elemental distribution, with the lowest energy arrangements then reminimised using Density Functional Theory (DFT). Force-field calculations show Au atoms preferentially occupy sub-surface positions in the bimetallic structures, which results in the formation of a pseudo-onion structure for Ag-rich compositions. At the DFT-level, however, an Ag core surrounded by an Au shell (Ag@Au) is energetically favoured, as electron density can be drawn more readily when Au atoms are positioned on the nanocluster surface, thus resulting in a partial negative charge. Core@shell configurations are analogous to structures that can be chemically synthesised, and further detailed electronic analysis is discussed in the context of nanocluster applications to co-catalysed photocatalysis.

Optical and electronic properties of mixed Ag-Au tetramer cations.

We present experimental and theoretical studies of the optical response of mixed Ag(n)Au(+)(4-n) (n=1-3) clusters in the photon energy range ℏω = 1.9-3.5 eV. Absorption spectra are recorded by a newly built longitudinal molecular beam depletion spectroscopy apparatus providing lower limits to absolute photodissociation cross sections. The experimental data are compared to optical response calculations in the framework of long-range corrected time-dependent density functional theory with initial cluster geometries obtained by the unbiased Birmingham Cluster Genetic Algorithm coupled with density functional theory. Experiments and excited state calculations shed light on the structural and electronic properties of the mixed Ag-Au tetramer cations.

Topically applied KTTKS: a review.

Skin ageing is an irreversible process that is caused by both intrinsic and extrinsic factors. The possibility of arresting or delaying skin ageing represents a large research area and has a big potential in the cosmetics sector. Recently, the polypeptide lysine-threonine-threonine-lysine-serine (KTTKS) has attracted a lot of attention and it features in numerous up-market cosmetic products where it has become erroneously associated with the term 'pentapeptide'. In this study, we review in detail KTTKS and its major derivatives, in terms of the limited information in the literature and an appraisal of its physicochemical and theoretical skin permeation properties. There appears to be a sound in vitro basis for its action on fibroblasts due to its stimulatory effect on extracellular matrix synthesis, where the stimulatory effect of KTTKS is specific to collagen types I and III and fibronectin expression. However, there is a surprising absence of in vitro skin penetration data in the literature, and there are relatively few clinical studies using these materials.

Pre-treatment with Aloe vera juice does not enhance the in vitro permeation of ketoprofen across skin.

BACKGROUND/AIMS: The potential of pre-treating skin with Aloe vera juice as a penetration enhancer was evaluated in vitro using ketoprofen as model permeant. METHODS: To excised porcine skin mounted in Franz diffusion cells was applied either: (1) commercial Aloe vera; (2) commercial Aloe vera followed by massaging; (3) previously boiled commercial Aloe vera; (4) water (negative control); (5) tea tree oil (positive control). After 1 h, the pre-treatment was removed and the skin dosed with a saturated solution of ketoprofen in polyethylene glycol 400; the appearance of drug in the receptor phase was then monitored by HPLC. RESULTS: No statistically significant differences in the transdermal delivery of ketoprofen were observed between water and all the Aloe vera pre-treatments (p > 0.05). The tea tree oil pre-treatment was significantly different to all others (p < 0.05). CONCLUSION: Aloe vera appears to have no value as a penetration enhancer when used as a pre-treatment, although the data indirectly support the mechanism of action proposed previously, work when used 'within-vehicle'. Handling household products containing Aloe vera appears not to leave the user at elevated risk of subsequent absorption of exogenous chemicals.

Control of microbial contamination of Franz diffusion cell receptor phase in the development of transcutaneous breast cancer therapeutics.

AIMS: To determine the micro-organism contamination of excised porcine (pig) ear, and evaluate the use of Cyclopore track-etched membranes (CTEM) for preventing ingress into Franz-type diffusion cells. METHODS: Swabs were taken from four locations and used to inoculate Tryptone Soya Agar (TSA) and Sabouraud Dextrose Agar (SDA) plates. Diffusion cells were assembled to include porcine skin with and without CTEM, and the receptor phase sampled periodically and spread onto plates. RESULTS: Five distinct colony types were isolated after incubation of all swabs on TSA plates at 37 degrees C; on SDA plates, one fungal colony was found at 30 degrees C and one at 37 degrees C. The SDA agar plate incubated at 30 degrees C resulted in the growth of a large diffused white fungal colony. No regional differences were observed. Without the CTEM, the receptor phase became contaminated within 6 h. With the CTEM present, microbial ingress was substantially retarded with visible presumptive fungal growth occurring at 24 h and detectable contamination on both microbiological media at 48 h. CONCLUSIONS: As expected, the native porcine ears were considerably contaminated. The ingress of contamination into the diffusion cell receptor phases can be largely, but not entirely, eliminated using CTEM. The addition of antimicrobial agents was necessary to eliminate micro-organisms that were observed at later time points. SIGNIFICANCE AND IMPACT OF THE STUDY: This article, while highlighting the presence of a high number of micro-organisms on native porcine skin, presents a practical means to reduce the risk of microbial contamination in transdermal/transcutaneous permeation studies, particularly in the study of cell cultures grown within Franz diffusion cell receptor compartments.

Scope and limitations of the co-drug approach to topical drug delivery.

Many currently available drugs show unfavourable physicochemical properties for delivery into or across the skin and temporary chemical modulation of the penetrant is one option to achieve improved delivery properties. Pro-drugs are chemical derivatives of an active drug which is covalently bonded to an inactive pro-moiety in order to overcome pharmaceutical and pharmacokinetic barriers. A pro-drug relies upon conversion within the body to release the parent active drug (and pro-moiety) to elicit its pharmacological effect. The main drawback of this approach is that the pro-moiety is essentially an unwanted ballast which, when released, can lead to adverse effects. The term 'co-drug' refers to two or more therapeutic compounds active against the same disease bonded via a covalent chemical linkage and it is this approach which is reviewed for the first time in the current article. For topically applied co-drugs, each moiety is liberated in situ, either chemically or enzymatically, once the stratum corneum barrier has been overcome by the co-drug. Advantages include synergistic modulation of the disease process, enhancement of drug delivery and pharmacokinetic properties and the potential to enhance stability by masking of labile functional groups. The amount of published work on co-drugs is limited but the available data suggest the co-drug concept could provide a significant therapeutic improvement in dermatological diseases. However, the applicability of the co-drug approach is subject to strict limitations pertaining mainly to the availability of compatible moieties and physicochemical properties of the overall molecule.

Topical delivery of retinyl ascorbate co-drug. 5. In vitro degradation studies.

Chemical and enzymatic hydrolysis of the co-drug of retinoic acid (vitamin A) and ascorbic acid (vitamin C) - retinyl ascorbate (RA-AsA)--have been studied. Firstly, the amount of protein and ester hydrolysis activity was determined in crude cellular extracts from freshly excised porcine ear skin (<3 h) and stored porcine ear skin (frozen >6 months) using ethyl butyrate as model substrate. The stability of RA-AsA was then determined in the crude cell extracts with and without additional antioxidants. Lastly, the enzymatic hydrolysis of RA-AsA and retinyl-2-carboxy-2-hydroxy-ethanoate were determined by incubating with porcine liver esterase - retinol palmitate and ascorbyl palmitate were included for comparison. Freshly excised skin contained higher amounts of active proteins than previously frozen skin. RA-AsA underwent hydrolytic reduction causing the AsA moiety to disintegrate due to the presence of free radicals in the media. An intermediate was produced that seemed to be cleaved by enzymes. Addition of ascorbic acid, as antioxidant, to the media of crude protein extracts decelerated the hydrolysis rate. This was supported when RA-AsA and retinyl-2-carboxy-2-hydroxy-ethanoate were incubated separately with pure esterase. There was approximately 5-fold more soluble protein per ml of cytosol in the fresh skin compared to the stored skin. Therefore, the amount of protein present within approximately 1.5 cm(2) of skin (average diffusion area in the Franz cells used in our skin penetration studies) was 0.06 mg cm(-2) and 0.01 mg cm(-2) for fresh and stored extracts, respectively.

Topical delivery of retinyl ascorbate co-drug: 6. Determination of toxic dose and antioxidant activity in cultured human epidermal keratinocytes.

The maximum effective dose of retinyl ascorbate and its potential therapeutic benefits against induced oxidative damage were assessed in vitro using cultured human epidermal keratinocytes. RA-AsA exhibited toxic effects at concentrations >6 microM. The findings indicate to the potency of RA-AsA as free radical scavenger and cell proliferation regulator.

Solvent content and macroviscosity effects on the in vitro transcutaneous delivery and skin distribution of ketoprofen from simple gel formulations.

The effects of decreasing solvent content and macroviscosity of simple topical gel formulations on the transcutaneous delivery and distribution of ketoprofen through skin were studied. Simple topical gels, based on ketoprofen, PEG 400 and either Cabosil M-5 or hydroxypropylcellulose were formulated and applied to freshly excised pig ear skin in vitro. Receptor phase samples were taken to determine permeation and depth profiles of ketoprofen were constructed, following tape stripping and membrane separation. Reduction of solvent from the Cabosil-thickened gels resulted in a rank order reduction in the permeation and distribution of ketoprofen. Reduced amounts of ketoprofen were distributed through the skin, particularly the dermis, with decreasing solvent. Two gels sharing the same macroviscosity exhibited significantly different skin permeation and distribution characteristics. The rank order reduction in both permeation and distribution of ketoprofen was attributed to the physiochemical properties of the formulation and how they may change after application, in particular the increased adsorptivity of ketoprofen to the Cabosil relative to the amount of solvent present in the system. This effect appeared to be predominant over any interactions occurring between the formulation and the skin. The data provided further evidence that adsorption to the thickener, rather than changes in viscosity, were primarily responsible for reduced permeation and distribution in the system examined.

Inter- and intralaboratory variation of in vitro diffusion cell measurements: an international multicenter study using quasi-standardized methods and materials.

In vitro measurements of skin absorption are an increasingly important aspect of regulatory studies, product support claims, and formulation screening. However, such measurements are significantly affected by skin variability. The purpose of this study was to determine inter- and intralaboratory variation in diffusion cell measurements caused by factors other than skin. This was attained through the use of an artificial (silicone rubber) rate-limiting membrane and the provision of materials including a standard penetrant, methyl paraben (MP), and a minimally prescriptive protocol to each of the 18 participating laboratories. "Standardized" calculations of MP flux were determined from the data submitted by each laboratory by applying a predefined mathematical model. This was deemed necessary to eliminate any interlaboratory variation caused by different methods of flux calculations. Average fluxes of MP calculated and reported by each laboratory (60 +/- 27 microg cm(-2) h(-1), n = 25, range 27-101) were in agreement with the standardized calculations of MP flux (60 +/- 21 microg cm(-2) h(-1), range 19-120). The coefficient of variation between laboratories was approximately 35% and was manifest as a fourfold difference between the lowest and highest average flux values and a sixfold difference between the lowest and highest individual flux values. Intralaboratory variation was lower, averaging 10% for five individuals using the same equipment within a single laboratory. Further studies should be performed to clarify the exact components responsible for nonskin-related variability in diffusion cell measurements. It is clear that further developments of in vitro methodologies for measuring skin absorption are required.

Topical delivery of retinyl ascorbate co-drug. 2. Comparative skin tissue and keratin binding studies.

Retinyl ascorbate (RA-AsA), an ester co-drug of vitamins A (RA) and C (AsA), is proposed as a topical antioxidant/cell division regulator for reducing UV-induced generation of free radicals and disrupted dermal cell growth. The efficacy of dermatological agents is influenced by their retention within the skin, which is increased by the interaction with skin components. Keratin is the major protein (approximately 95%) in the skin, and this paper reports the binding of RA-AsA, RA, AsA, retinol, ascorbic acid palmitate and retinol palmitate to three tissues-human callus, pig ear skin and bovine horn keratin. Tissue samples were incubated with solutions of compounds and the uptake measured as the ratio of bound/free compound at equilibrium. Binding to keratin was assessed using delipidised tissue, and was much higher for the polar compounds, suggesting dipolar/H-bonding interaction. Binding strength was ranked as human > porcine > bovine, but there was no distinction for highly lipophilic compounds. The binding characteristic of native tissues was complicated by lipid content of the tissues. There seemed to be a dual effect. The binding of very lipophilic materials increased with lipid content, implying that a substantial amount is dissolved in the lipid matrix. For highly polar AsA, lipid content decreased the binding, suggesting that the lipid reduced the strong polar interactions with skin protein/keratin.

Binding of primaquine to epidermal membranes and keratin.

The localisation of primaquine was studied within epidermal membranes following the application of a topical dose. A depth profile was constructed by tape-stripping human epidermis following permeation of a 70 mgml(-1) solution of primaquine in Miglyol 840. Comparative binding studies of primaquine were carried out on isolated human stratum corneum and whole epidermis, using normal and delipidised tissue. An additional study was undertaken using bovine keratin powder as a model of human keratin. The depth profile showed that primaquine decreased with depth and decreasing keratin content, and the total primaquine recovered (15.5 mgcm(-2)) was 300 x the amount of extractable lipid. Binding to delipidised skin was saturable, whereas binding to normal skin was unsaturable, reflecting the high miscibility of drug in the lipid domains as opposed to a finite, but large number of binding sites on the corneocytes. Binding was greater for stratum corneum than stratum corneum plus viable epidermis, probably due to greater accessibility of corneocytes keratin. Binding was dose dependent, although binding to delipidised skin was far greater than to normal skin, demonstrating that primaquine had an affinity for lipoidal regions and an even higher affinity for the proteinaceous domains of the stratum corneum. This was supported by high saturable levels of primaquine binding to bovine horn keratin. The results indicated extensive binding to corneocyte keratin has a significant effect on reservoir formation and the permeability of primaquine across human skin. It is speculated that the large amount of keratin presented at the skin surface may be an evolutionary protective process for the sequestration of ingressing molecules.

Direct enantiomeric resolution of some cardiovascular agents using synthetic polymers imprinted with (-)-S-timolol as chiral stationary phase by thin layer chromatography.

Molecular imprinted polymers (MIPs) of S-timolol were prepared as chiral stationary phases (CSPs) in thin layer chromatography (TLC). The resolution of the enantiomers of some cardiovascular drugs, including propranolol, atenolol, timolol, nadolol, nifedipine and verapamil were investigated on these CSPs. A mobile phase system of either methanol or acetonitrile was used and the effects of acetic acid content of the mobile phases were also investigated. The best resolution was achieved for enantioseparation of propranolol, timolol and atenolol on plates based on MIP of (-)-S-timolol using methacrylic acid as functional monomer (alpha = 1.52, 1.6, 1.59) respectively, using acetonitrile containing 5% acetic acid and (alpha = 1.47, 1.52, 1.5) in methanol containing 1% acetic acid as mobile phases. The results obtained show that TLC based on MIPs could be applied in the direct separation of several beta-adrenergic drugs. As the side chains on beta-blockers are similar, it is possible that this method could also be used for the resolution of other racemates in this family of drugs. Racemic drugs structurally related to print molecule, were completely resolved into two spots with the MIP plates. In general the retention of (+)-R-isomers was greater than that of (-)-S-isomers, indicating lower stereoselectivity of the MIPs to the dextrorotatory isomers. The method offers a rapid, sensitive and reliable method for quality control for these drugs.

A review of modifications to recombinant antibodies: attempt to increase efficacy in oncology applications.

Although monoclonal antibodies have high specificity, their usefulness in the clinic, especially against solid tumors, has been limited. This arises in part from the inability of antibody molecules to penetrate into the tumor and kill the tumor cells. In addition, natural cytotoxic effects of antibodies, mediated through complement or Fc receptors, may not be sufficient to kill malignant cells. This review will present some of the antibody modifications used to increase efficacy. Modified recombinant antibodies have been designed to be more cytotoxic (immunotoxins), to increase natural effector functions (bivalent antibodies, antibody-fusion molecules, multimeric antibodies, directed mutations in Fc region), or to pretarget cells for concentration of cytotoxic drugs. This review will also focus on engineering of smaller versions of antibodies that retain specificity (single chain Fvs, Fabs, Fab(2)s, minibodies, domain deleted antibodies) and have increased penetrability of solid tumors. Many of these antibody modifications may result in antigenic compounds which can limit repeat administration. Clinical experiences will be highlighted if information is available.

Use of a physiologic scoring system during interhospital transport of pediatric patients.

OBJECTIVE: To determine the incidence of physiologic deterioration in critically ill and injured pediatric patients during interhospital transport with air and ground ambulance DESIGN: Prospective, descriptive study SETTING: All children were treated in regional hospitals and then transported to a pediatric tertiary care center. PATIENTS: Children (n = 100) with a median age of 1.4 years (range 1 week to 18 years) MAIN RESULTS: Three sets of physiologic scores were calculated: at the time of referral, on departure from the referring hospital, and arrival at the tertiary care center. The incidence of significant physiologic deterioration based on the calculated physiologic scores was 5.6% (n = 4) during ground and 3.4% (n = 1) during air ambulance transports. Critical events occurred in 15% of ground and 31% of air ambulance transports. CONCLUSION: No difference existed in the incidence of adverse events or physiologic deterioration when air ambulance transports were compared with ground ambulance transports for critically ill children by our team. The physiologic scoring system we chose is simple and easy to use for quality assurance.