Pharmacokinetics, pharmacodynamics and clinical use of trazodone and its active metabolite m-chlorophenylpiperazine in the horse.

Trazodone is a serotonin receptor antagonist and reuptake inhibitor used extensively as an anxiolytic in human and small animal veterinary medicine. The aims of this study were to determine the pharmacokinetics of oral trazodone in experimental horses and to evaluate the effect of oral trazodone in clinical horses. Six experimental horses were administered trazodone at 7.5 or 10 mg/kg. Plasma concentrations of trazodone and its metabolite (m-CPP) were determined via UPLC-MS/MS. Noncompartmental pharmacokinetic analysis, sedation and ataxia scores were determined. Trazodone was rapidly absorbed after oral administration with a maximum concentration of 2.5-4.1 µg/ml and half-life of the terminal phase of approximately 7 hr. The metabolite was present at low levels in all horses, representing only 2.5% of the total area under the curve. In experimental horses, concentration-dependent sedation and ataxia were noted, lasting up to 12 hr. For clinical cases, medical records of horses treated with trazodone for various abnormal behaviours were reviewed and data were summarized. Trazodone was successful in modifying behavioural problems to some degree in 17 of 18 clinical cases. Tolerance and subsequent lack of drug effect occurred in two of 18 clinical cases following 14 or 21 days of use. In both populations of horses, adverse effects attributed to trazodone include oversedation, muscle fasciculations and transient arrhythmias.

Pharmacokinetics of firocoxib after intravenous administration of multiple consecutive doses in neonatal foals.

The purpose of this study was to determine the pharmacokinetic profile of intravenous firocoxib in neonatal foals. Six healthy foals were administered 0.09 mg/kg firocoxib intravenously once a day for 7 days. Blood was collected for plasma firocoxib analysis using high-performance liquid chromatography with fluorescence detection at times 0 (day 1 of study only) and 0.08, 0.25, 1, 2, 4, 6, 8, 16 and 24 hr on dose numbers 1, 5 and 7. Blood was also collected immediately prior to doses 3, 4, 5 and 7. Final samples were collected at 36, 48, 72 and 96 hr following the final dose. Noncompartmental analysis using the trapezoidal method with linear interpolation revealed a moderate half-life (15.9 ± 9.1 hr) with a large volume of distribution at steady state (1.79 ± 0.57 L/kg) and a clearance (96.0 ± 59.2 ml h-1  kg-1 ) that was more rapid than that observed in adult horses.

Xpert MTB/RIF Assay Shows Faster Clearance of Mycobacterium tuberculosis DNA with Higher Levels of Rifapentine Exposure.

The Xpert MTB/RIF assay is both sensitive and specific as a diagnostic test. Xpert also reports quantitative output in cycle threshold (CT) values, which may provide a dynamic measure of sputum bacillary burden when used longitudinally. We evaluated the relationship between Xpert CT trajectory and drug exposure during tuberculosis (TB) treatment to assess the potential utility of Xpert CT for treatment monitoring. We obtained serial sputum samples from patients with smear-positive pulmonary TB who were consecutively enrolled at 10 international clinical trial sites participating in study 29X, a CDC-sponsored Tuberculosis Trials Consortium study evaluating the tolerability, safety, and antimicrobial activity of rifapentine at daily doses of up to 20 mg/kg of body weight. Xpert was performed at weeks 0, 2, 4, 6, 8, and 12. Longitudinal CT data were modeled using a nonlinear mixed effects model in relation to rifapentine exposure (area under the concentration-time curve [AUC]). The rate of change of CT was higher in subjects receiving rifapentine than in subjects receiving standard-dose rifampin. Moreover, rifapentine exposure, but not assigned dose, was significantly associated with rate of change in CT (P = 0.02). The estimated increase in CT slope for every additional 100 µg · h/ml of rifapentine drug exposure (as measured by AUC) was 0.11 CT/week (95% confidence interval [CI], 0.05 to 0.17). Increasing rifapentine exposure is associated with a higher rate of change of Xpert CT, indicating faster clearance of Mycobacterium tuberculosis DNA. These data suggest that the quantitative outputs of the Xpert MTB/RIF assay may be useful as a dynamic measure of TB treatment response.

Donor-derived Strongyloides stercoralis infection in solid organ transplant recipients in the United States, 2009-2013.

Infection with Strongyloides stercoralis is typically asymptomatic in immunocompetent hosts, despite chronic infection. In contrast, immunocompromised hosts such as solid organ transplant recipients are at risk for hyperinfection syndrome and/or disseminated disease, frequently resulting in fatal outcomes. Infection in these recipients may result from reactivation of latent infection or infection through transmission from an infected donor. We describe the Centers for Disease Control and Prevention's experience with seven clusters of donor-derived infection from 2009 to 2013. Six of the seven (86%) donors were born in Latin America; donor screening was not performed prior to organ transplantation in any of these investigations. Eleven of the 20 (55%) organ recipients were symptomatic, two of whom died from complications of strongyloidiasis. We also describe the New York Organ Donor Network (NYODN) experience with targeted donor screening from 2010 to 2013. Of the 233 consented potential donors tested, 10 tested positive for Strongyloides antibody; and 18 organs were transplanted. The majority (86%) of the donors were born in Central or South America. Fourteen recipients received prophylaxis after transplantation; no recipients developed strongyloidiasis. The NYODN experience provides evidence that when targeted donor screening is performed prior to transplantation, donor-derived infection can be averted in recipients.

Pharmacokinetics of danofloxacin and N-desmethyldanofloxacin in adult horses and their concentration in synovial fluid.

The objectives of this study were to investigate the pharmacokinetics of danofloxacin and its metabolite N-desmethyldanofloxacin and to determine their concentrations in synovial fluid after administration by the intravenous, intramuscular or intragastric routes. Six adult mares received danofloxacin mesylate administered intravenously (i.v.) or intramuscularly (i.m.) at a dose of 5 mg/kg, or intragastrically (IG) at a dose of 7.5 mg/kg using a randomized Latin square design. Concentrations of danofloxacin and N-desmethyldanofloxacin were measured by UPLC-MS/MS. After i.v. administration, danofloxacin had an apparent volume of distribution (mean ± SD) of 3.57 ± 0.26 L/kg, a systemic clearance of 357.6 ± 61.0 mL/h/kg, and an elimination half-life of 8.00 ± 0.48 h. Maximum plasma concentration (Cmax ) of N-desmethyldanofloxacin (0.151 ± 0.038 µg/mL) was achieved within 5 min of i.v. administration. Peak danofloxacin concentrations were significantly higher after i.m. (1.37 ± 0.13 µg/mL) than after IG administration (0.99 ± 0.1 µg/mL). Bioavailability was significantly higher after i.m. (100.0 ± 12.5%) than after IG (35.8 ± 8.5%) administration. Concentrations of danofloxacin in synovial fluid samples collected 1.5 h after administration were significantly higher after i.v. (1.02 ± 0.50 µg/mL) and i.m. (0.70 ± 0.35 µg/mL) than after IG (0.20 ± 0.12 µg/mL) administration. Monte Carlo simulations indicated that danofloxacin would be predicted to be effective against bacteria with a minimum inhibitory concentration (MIC) ≤0.25 µg/mL for i.v. and i.m. administration and 0.12 µg/mL for oral administration to maintain an area under the curve:MIC ratio ≥50.

Pharmacokinetics and pharmacodynamics of three formulations of firocoxib in healthy horses.

The objectives of this study were to compare the pharmacokinetics and COX selectivity of three commercially available formulations of firocoxib in the horse. Six healthy adult horses were administered a single dose of 57 mg intravenous, oral paste or oral tablet firocoxib in a three-way, randomized, crossover design. Blood was collected at predetermined times for PGE2 and TXB2 concentrations, as well as plasma drug concentrations. Similar to other reports, firocoxib exhibited a long elimination half-life (31.07 ± 10.64 h), a large volume of distribution (1.81 ± 0.59L/kg), and a slow clearance (42.61 ± 11.28 mL/h/kg). Comparison of the oral formulations revealed a higher Cmax , shorter Tmax , and greater AUC for the paste compared to the tablet. Bioavailability was 112% and 88% for the paste and tablet, respectively. Maximum inhibition of PGE2 was 83.76% for the I.V. formulation, 52.95% for the oral paste formulation, and 46.22% for the oral tablet formulation. Pharmacodynamic modeling suggests an IC50 of approximately 27 ng/mL and an IC80 of 108 ng/ mL for COX2 inhibition. Inhibition of TXB2 production was not detected. This study indicates a lack of bioequivalence between the oral formulations of firocoxib when administered as a single dose to healthy horses.

Pharmacokinetics and physiologic effects of alprazolam after a single oral dose in healthy mares.

The objective of this study was to evaluate the pharmacokinetic properties and physiologic effects of a single oral dose of alprazolam in horses. Seven adult female horses received an oral administration of alprazolam at a dosage of 0.04 mg/kg body weight. Blood samples were collected at various time points and assayed for alprazolam and its metabolite, α-hydroxyalprazolam, using liquid chromatography/mass spectrometry. Pharmacokinetic disposition of alprazolam was analyzed by a one-compartmental approach. Mean plasma pharmacokinetic parameters (±SD) following single-dose administration of alprazolam were as follows: Cmax 14.76 ± 3.72 ng/mL and area under the curve (AUC0-∞ ) 358.77 ± 76.26 ng·h/mL. Median (range) Tmax was 3 h (1-12 h). Alpha-hydroxyalprazolam concentrations were detected in each horse, although concentrations were low (Cmax 1.36 ± 0.28 ng/mL). Repeat physical examinations and assessment of the degree of sedation and ataxia were performed every 12 h to evaluate for adverse effects. Oral alprazolam tablets were absorbed in adult horses and no clinically relevant adverse events were observed. Further evaluation of repeated dosing and safety of administration of alprazolam to horses is warranted.

Pharmacokinetics and safety of firocoxib after oral administration of repeated consecutive doses to neonatal foals.

The purpose of this study was to determine the pharmacokinetics and safety profile of firocoxib in neonatal foals. Seven healthy foals were administered 0.1 mg/kg firocoxib orally q24 h for nine consecutive days, commencing at 36 h of age. Blood was collected for firocoxib analysis using high-pressure liquid chromatography with fluorescence detection at 0 (dose #1 only), 0.25, 0.5, 1, 2, 4, 8, 16, and 24 h after doses 1, 5, and 9. For all other doses (2, 3, 4, 6, 7, and 8), blood was collected immediately prior to the next dose (24 h trough). Elimination samples (36, 48, 72, 96, 120, and 144 h) were collected after dose 9. Safety was assessed via physical examinations, body weight measurements, gastroscopy, complete blood count, plasma biochemistry and urinalysis. Firocoxib was rapidly absorbed following oral administration with minimal accumulation after repeat dosing. After the final dose, the terminal half-life was approximately 11 h. Firocoxib was below the limit of detection (<2.5 ng/mL) in plasma 72 h after the final dose. No significant abnormalities were found on blood analyses, urinalysis, or gastroscopy. This study demonstrated that firocoxib is absorbed in neonatal foals with no demonstrable adverse effects after repeated doses of 0.1 mg/kg.

An adapted scale to measure perceived TB and HIV stigma during household contact investigation.

Measuring stigma for TB and HIV in households undergoing contact investigation for TB is critical for understanding its impacts on health behaviours and identifying opportunities for intervention. However, standardised measurements for TB-HIV stigma in household contact investigations are limited.We adapted and validated a household stigma scale in Uganda. This involved field testing measures from another setting with 163 household contacts of newly diagnosed TB patients, conducting cognitive interviews with seven household contacts, adapting scale items using cognitive interview data, and retesting the adapted scales in a random sample of 60 contacts. We assessed inter-item covariance and performed factor analysis to select the final scale items.In whole-scale factor analysis, no cross-loading of items with scores ≥0.32 was found after the elimination of items based on covariance and symmetry. All TB items were loaded onto a single factor with scores ≥0.5, and all but one HIV item was loaded onto a second factor with scores ≥0.5. The final subscale internal consistency (Cronbach's alpha) was 0.92 for TB and 0.89 for HIV.The adapted TB-HIV stigma scale demonstrated acceptable psychometric properties and is substantially shorter and easier to administer than previous scales, making it suitable for programmatic research and evaluation..

Lung function and health-related quality of life among adult patients following pulmonary TB treatment.

Pulmonary TB (PTB) increases the risk of chronic lung complications, which are associated with increased morbidity and mortality. We determined the prevalence and predictors of post-TB lung disease and persistent symptoms in a resource-limited setting.Adults who completed PTB treatment underwent spirometry and completed the St. George's Respiratory Questionnaire (SGRQ), a questionnaire that assesses quality of life on symptom, activity, and impact. We performed multivariate analyses to calculate the X-adjusted prevalence ratio (PRadj) of abnormal spirometry and identify associated risk factors.Among the 162 participants, 89 (54.9%) were male. The median age was 32 years, and 65 (40.1%) had HIV. Overall, 65 participants (40.1%) had abnormal lung function, with spirometric restriction seen in 29.0%, obstruction in 4.9%, and a mixed pattern in 6.2%. Smoking (PRadj 1.88, 95% CI 1.11-3.16; P = 0.02) and female sex (PRadj 1.81, 95% Cl 1.15-2.84; P = 0.01) were independent risk factors for abnormal lung function. The median SGRQ scores were higher in participants with cavitation (P < 0.001) or bilateral consolidation on initial chest X-ray (P = 0.01).Lung function abnormalities, particularly spirometric restriction, are common in patients completing PTB treatment. Female sex and smoking status were associated with lung function abnormalities; therefore, additional studies to understand the underlying mechanistic pathways are warranted..

Pharmacokinetics of tobramycin following intravenous, intramuscular, and intra-articular administration in healthy horses.

The objectives of this study were to examine the pharmacokinetics of tobramycin in the horse following intravenous (IV), intramuscular (IM), and intra-articular (IA) administration. Six mares received 4 mg/kg tobramycin IV, IM, and IV with concurrent IA administration (IV+IA) in a randomized 3-way crossover design. A washout period of at least 7 days was allotted between experiments. After IV administration, the volume of distribution, clearance, and half-life were 0.18 ± 0.04 L/kg, 1.18 ± 0.32 mL·kg/min, and 4.61 ± 1.10 h, respectively. Concurrent IA administration could not be demonstrated to influence IV pharmacokinetics. The mean maximum plasma concentration (Cmax ) after IM administration was 18.24 ± 9.23 µg/mL at 1.0 h (range 1.0-2.0 h), with a mean bioavailability of 81.22 ± 44.05%. Intramuscular administration was well tolerated, despite the high volume of drug administered (50 mL per 500 kg horse). Trough concentrations at 24 h were below 2 µg/mL in all horses after all routes of administration. Specifically, trough concentrations at 24 h were 0.04 ± 0.01 µg/mL for the IV route, 0.04 ± 0.02 µg/mL for the IV/IA route, and 0.02 ± 0.02 for the IM route. An additional six mares received IA administration of 240 mg tobramycin. Synovial fluid concentrations were 3056.47 ± 1310.89 µg/mL at 30 min after administration, and they persisted for up to 48 h with concentrations of 14.80 ± 7.47 µg/mL. Tobramycin IA resulted in a mild chemical synovitis as evidenced by an increase in synovial fluid cell count and total protein, but appeared to be safe for administration. Monte Carlo simulations suggest that tobramycin would be effective against bacteria with a minimum inhibitory concentration (MIC) of 2 µg/mL for IV administration and 1 µg/mL for IM administration based on Cmax :MIC of 10.

Geographic distribution and predictors of diagnostic delays among possible TB patients in Uganda.

BACKGROUND: Understanding the geographic distribution and factors associated with delayed TB diagnosis may help target interventions to reduce delays and improve patient outcomes. METHODS: We conducted a secondary analysis of adults undergoing TB evaluation within a public health demonstration project in Uganda. Using Global Moran's I (GMI) and Getis-Ord GI* statistics, we evaluated for residential clustering and hotspots associated with patient-related and health system-related delays. We performed multivariate logistic regression to identify individual predictors of both types of delays. RESULTS: Of 996 adults undergoing TB evaluation (median age: 37 years, IQR 28-49), 333 (33%) experienced patient delays, and 568 (57%) experienced health system delays. Participants were clustered (GMI 0.47-0.64, P ⩽ 0.001) at the sub-county level, but there were no statistically significant hotspots for patient or health system delays. Married individuals were less likely to experience patient delays (OR 0.6, 95% CI 0.48-0.75; P < 0.001). Those aged 38-57 years (OR 1.2, 95% CI 1.07-1.38; P = 0.002) were more likely than those aged ⩾58 years to experience patient delays. Knowledge about TB (OR 0.8, 95% CI 0.63-0.98; P = 0.03) protected against health system delays. CONCLUSIONS: We did not identify geographic hotspots for TB diagnostic delays. Instead, delays were associated with individual factors such as age, marital status and TB knowledge.

CONTEXTE: Comprendre la distribution géographique et les facteurs associés aux retards de diagnostic de la TB peut aider à cibler les interventions visant à réduire les retards et à améliorer les résultats pour les patients. MÉTHODES: Nous avons effectué une analyse secondaire des adultes soumis à une évaluation de la TB dans le cadre d'un projet de démonstration de santé publique en Ouganda. À l'aide des statistiques Global Moran's I (GMI) et Getis-Ord GI*, nous avons évalué les regroupements résidentiels et les points critiques associés aux retards liés aux patients et au système de santé. Nous avons effectué une régression logistique multivariée pour identifier les prédicteurs individuels des deux types de retards. RÉSULTATS: Sur les 996 adultes soumis à une évaluation de la TB (âge médian : 37 ans, IQR 28­49), 333 (33%) ont subi des retards liés aux patients et 568 (57%) ont subi des retards liés au système de santé. Les participants étaient regroupés (GMI 0,47­0,64 ; P ⩽ 0,001) au niveau du sous-comté, mais il n'y avait pas de points critiques statistiquement significatifs pour les retards des patients ou du système de santé. Les personnes mariées étaient moins susceptibles de subir des retards de la part des patients (OR 0,6 ; 95% CI 0,48­0,75 ; P < 0,001). Les personnes âgées de 38 à 57 ans (OR 1,2 ; 95% CI 1,07­1,38 ; P = 0,002) étaient plus susceptibles que celles âgées de ⩾58 ans de subir des retards. Les connaissances sur la TB (OR 0,8 ; 95% CI 0,63­0,98 ; P = 0,03) protégeaient contre les retards du système de santé. CONCLUSIONS: Nous n'avons pas identifié de points critiques géographiques pour les retards de diagnostic de la TB. Les retards étaient plutôt associés à des facteurs individuels tels que l'âge, la situation matrimoniale et les connaissances sur la TB.

Subcontinental-scale crustal velocity changes along the Pacific-North America plate boundary.

Transient tectonic deformation has long been noted within approximately 100 km of plate boundary fault zones and within active volcanic regions, but it is unknown whether transient motions also occur at larger scales within plates. Relatively localized transients are known to occur as both seismic and episodic aseismic events, and are generally ascribed to motions of magma bodies, aseismic creep on faults, or elastic or viscoelastic effects associated with earthquakes. However, triggering phenomena and systematic patterns of seismic strain release at subcontinental (approximately 1,000 km) scale along diffuse plate boundaries have long suggested that energy transfer occurs at larger scale. Such transfer appears to occur by the interaction of stresses induced by surface wave propagation and magma or groundwater in the crust, or from large-scale stress diffusion within the oceanic mantle in the decades following clusters of great earthquakes. Here we report geodetic evidence for a coherent, subcontinental-scale change in tectonic velocity along a diffuse approximately 1,000-km-wide deformation zone. Our observations are derived from continuous GPS (Global Positioning System) data collected over the past decade across the Basin and Range province, which absorbs approximately 25 per cent of Pacific-North America relative plate motion. The observed changes in site velocity define a sharp boundary near the centre of the province oriented roughly parallel to the north-northwest relative plate motion vector. We show that sites to the west of this boundary slowed relative to sites east of it by approximately 1 mm yr(-1) starting in late 1999.

Pharmacokinetics of intravenous and intramuscular buprenorphine in the horse.

The purpose of this study was to determine the pharmacokinetics of buprenorphine following intravenous (i.v.) and intramuscular (i.m.) administration in horses. Six horses received i.v. or i.m. buprenorphine (0.005 mg/kg) in a randomized, crossover design. Plasma samples were collected at predetermined times and horses were monitored for adverse reactions. Buprenorphine concentrations were measured using ultra-performance liquid chromatography with electrospray ionization mass spectrometry. Following i.v. administration, clearance was 7.97±5.16 mL/kg/min, and half-life (T(1/2)) was 3.58 h (harmonic mean). Volume of distribution was 3.01±1.69 L/kg. Following i.m. administration, maximum concentration (C(max)) was 1.74±0.09 ng/mL, which was significantly lower than the highest measured concentration (4.34±1.22 ng/mL) after i.v. administration (P<0.001). Time to C(max) was 0.9±0.69 h and T(1/2) was 4.24 h. Bioavailability was variable (51-88%). Several horses showed signs of excitement. Gut sounds were decreased 10±2.19 and 8.67±1.63 h in the i.v. and i.m. group, respectively. Buprenorphine has a moderate T(1/2) in the horse and was detected at concentrations expected to be therapeutic in other species after i.v. and i.m. administration of 0.005 mg/kg. Signs of excitement and gastrointestinal stasis may be noted.

Assessing a norming intervention to promote acceptance of HIV testing and reduce stigma during household tuberculosis contact investigation: protocol for a cluster-randomised trial.

INTRODUCTION: HIV status awareness is important for household contacts of patients with tuberculosis (TB). Home HIV testing during TB contact investigation increases HIV status awareness. Social interactions during home visits may influence perceived stigma and uptake of HIV testing. We designed an intervention to normalise and facilitate uptake of home HIV testing with five components: guided selection of first tester; prosocial invitation scripts; opt-out framing; optional sharing of decisions to test; and masking of decisions not to test. METHODS AND ANALYSIS: We will evaluate the intervention effect in a household-randomised controlled trial. The primary aim is to assess whether contacts offered HIV testing using the norming strategy will accept HIV testing more often than those offered testing using standard strategies. Approximately 198 households will be enrolled through three public health facilities in Kampala, Uganda. Households will be randomised to receive the norming or standard strategy and visited by a community health worker (CHW) assigned to that strategy. Eligible contacts ≥15 years will be offered optional, free, home HIV testing. The primary outcome, proportion of contacts accepting HIV testing, will be assessed by CHWs and analysed using an intention-to-treat approach. Secondary outcomes will be changes in perceived HIV stigma, changes in perceived TB stigma, effects of perceived HIV stigma on HIV test uptake, effects of perceived TB stigma on HIV test uptake and proportions of first-invited contacts who accept HIV testing. Results will inform new, scalable strategies for delivering HIV testing. ETHICS AND DISSEMINATION: This study was approved by the Yale Human Investigation Committee (2000024852), Makerere University School of Public Health Institutional Review Board (661) and Uganda National Council on Science and Technology (HS2567). All participants, including patients and their household contacts, will provide verbal informed consent. Results will be submitted to a peer-reviewed journal and disseminated to national stakeholders, including policy-makers and representatives of affected communities. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Identifier: NCT05124665.

Perceptions, preferences, and experiences of tuberculosis education and counselling among patients and providers in Kampala, Uganda: A qualitative study.

Tuberculosis (TB) education seeks to increase patient knowledge about TB, while TB counselling seeks to offer tailored advice and support for medication adherence. While universally recommended, little is known about how to provide effective, efficient, patient-centred TB education and counselling (TEC) in low-income, high HIV-TB burden settings. We sought to characterise stakeholder perceptions of TEC in a public, primary care facility in Kampala, Uganda, by conducting focus group discussions with health workers and TB patients in the TB and HIV clinics. Participants valued TEC but reported that high-quality TEC is rarely provided, because of a lack of time, space, staff, planning, and prioritisation given to TEC. To improve TEC, they recommended adopting practices that have proven effective in the HIV clinic, including better specifying educational content, and employing peer educators focused on TEC. Patients and health workers suggested that TEC should not only improve TB patient knowledge and adherence, but should also empower and assist all those undergoing evaluation for TB, whether confirmed or not, to educate their households and communities about TB. Community-engaged research with patients and front-line providers identified opportunities to streamline and standardise the delivery of TEC using a patient-centred, peer-educator model.

The pharmacokinetics and in vitro cyclooxygenase selectivity of deracoxib in horses.

The purpose of this study was to determine the pharmacokinetics of deracoxib following oral administration to horses. In addition, in vitro equine whole blood cyclooxygenase (COX) selectivity assays were performed. Six healthy adult horses were administered deracoxib (2 mg/kg) orally. Plasma samples were collected prior to drug administration (time 0), and 10, 20, 40 min and 1, 1.5, 2, 4, 6, 8, 12, 24, and 48 h after administration for analysis with high pressure liquid chromatography using ultraviolet detection. Following PO administration, deracoxib had a long elimination half-life (t(1/2) k(10) ) of 12.49 ± 1.84 h. The average maximum plasma concentration (C(max) ) was 0.54 µg/mL, and was reached at 6.33 ± 3.44 h. Bioavailability was not determined because of the lack of an IV formulation. Results of in vitro COX selectivity assays showed that deracoxib was selective for COX-2 with a COX-1/COX-2 ratio of 25.67 and 22.06 for the IC(50) and IC(80) , respectively. Dosing simulations showed that concentrations above the IC(80) for COX-2 would be maintained following 2 mg/kg PO q12h, and above the IC(50) following 2 mg/kg PO q24h. This study showed that deracoxib is absorbed in the horse after oral administration, and may offer a useful alternative for anti-inflammatory treatment of various conditions in the horse.

Pharmacokinetics of pioglitazone after multiple oral dose administration in horses.

Pioglitazone is a thiazolidinedione class of antidiabetic agent with proven efficacy in increasing insulin sensitivity in humans with noninsulin-dependent diabetes mellitus, a syndrome of insulin resistance sharing similarities with equine metabolic syndrome. The purpose of this study was to determine the pharmacokinetics of pioglitazone in adult horses following multiple oral dose administration. Pioglitazone hydrochloride (1 mg/kg) was administered orally for 11 doses at 24-h intervals, and plasma samples were collected. Initially, a pilot study was performed using one horse; and thereafter the drug was administered to six horses. Samples were analyzed by liquid chromatography with tandem mass spectrometry, and pharmacokinetic parameters were calculated using noncompartmental modeling. The maximum plasma concentration was 509.1 ± 413.5 ng/mL achieved at 1.88 ± 1.39 h following oral administration of the first dose, and 448.1 ± 303.5 ng/mL achieved at 2.83 ± 1.81 h (mean ± SD) following the eleventh dose. Apparent elimination half-life was 9.94 ± 4.57 and 9.63 ± 5.33 h after the first and eleventh dose, respectively. This study showed that in healthy horses, pioglitazone administered at a daily oral dose of 1 mg/kg results in plasma concentrations and total drug exposure approximating, but slightly below, those considered therapeutic in humans.

Does bleach processing increase the accuracy of sputum smear microscopy for diagnosing pulmonary tuberculosis?

Bleach digestion of sputum prior to smear preparation has been reported to increase the yield of microscopy for diagnosing pulmonary tuberculosis, even in high-HIV-prevalence settings. To determine the diagnostic accuracy of bleach microscopy, we updated a systematic review published in 2006 and applied the Grading of Recommendations Assessment, Development, and Evaluation framework to rate the overall quality of the evidence. We searched multiple databases (as of January 2009) for primary studies in all languages comparing bleach and direct microscopy. We assessed study quality using a validated tool and heterogeneity by standard methods. We used hierarchical summary receiver operating characteristic (HSROC) analysis to calculate summary estimates of diagnostic accuracy and random-effects meta-analysis to pool sensitivity and specificity differences. Of 14 studies (11 papers) included, 9 evaluated bleach centrifugation and 5 evaluated bleach sedimentation. Overall, examination of bleach-processed versus direct smears led to small increases in sensitivity (for bleach centrifugation, 6% [95% confidence interval [CI] = 3 to 10%, P = 0.001]; for bleach sedimentation, 9% [95% CI = 4 to 14%, P = 0.001]) and small decreases in specificity (for bleach centrifugation, -3% [95% CI = -4% to -1%, P = 0.004]; for bleach sedimentation, -2% [95% CI = -5% to 0%, P = 0.05]). Similarly, analysis of HSROC curves suggested little or no improvement in diagnostic accuracy. The quality of evidence was rated very low for both bleach centrifugation and bleach sedimentation. This updated systematic review suggests that the benefits of bleach processing are less than those described previously. Further research should focus on alternative approaches to optimizing smear microscopy, such as light-emitting diode fluorescence microscopy and same-day sputum collection strategies.

Predicting bite force in mammals: two-dimensional versus three-dimensional lever models.

Bite force is a measure of whole-organism performance that is often used to investigate the relationships between performance, morphology and fitness. When in vivo measurements of bite force are unavailable, researchers often turn to lever models to predict bite forces. This study demonstrates that bite force predictions based on two-dimensional (2-D) lever models can be improved by including three-dimensional (3-D) geometry and realistic physiological cross-sectional areas derived from dissections. Widely used, the 2-D method does a reasonable job of predicting bite force. However, it does so by over predicting physiological cross-sectional areas for the masseter and pterygoid muscles and under predicting physiological cross-sectional areas for the temporalis muscle. We found that lever models that include the three dimensional structure of the skull and mandible and physiological cross-sectional areas calculated from dissected muscles provide the best predictions of bite force. Models that accurately represent the biting mechanics strengthen our understanding of which variables are functionally relevant and how they are relevant to feeding performance.