Pharmacological stimulation of infralimbic cortex after fear conditioning facilitates subsequent fear extinction.

The infralimbic (IL) division of the medial prefrontal cortex (mPFC) is a crucial site for the extinction of conditioned fear memories in rodents. Recent work suggests that neuronal plasticity in the IL that occurs during (or soon after) fear conditioning enables subsequent IL-dependent extinction learning. We therefore hypothesized that pharmacological activation of the IL after fear conditioning would promote the extinction of conditioned fear. To test this hypothesis, we characterized the effects of post-conditioning infusions of the GABAA receptor antagonist, picrotoxin, into the IL on the extinction of auditory conditioned freezing in male and female rats. In four experiments, we found that picrotoxin injections performed immediately, 24 h, or 13 days after fear conditioning reduced conditioned freezing to the auditory conditioned stimulus (CS) during both extinction training and extinction retrieval; this effect was observed up to two weeks after picrotoxin infusions. Interestingly, inhibiting protein synthesis inhibition in the IL immediately after fear conditioning prevented the inhibition of freezing by picrotoxin injected 24 h later. Our data suggest that the IL encodes an inhibitory memory during the consolidation of fear conditioning that is necessary for future fear suppression.

Pharmacological stimulation of infralimbic cortex after fear conditioning facilitates subsequent fear extinction.

The infralimbic (IL) division of the medial prefrontal cortex (mPFC) is a crucial site for extinction of conditioned fear memories in rodents. Recent work suggests that neuronal plasticity in the IL that occurs during (or soon after) fear conditioning enables subsequent IL-dependent extinction learning. We therefore hypothesized that pharmacological activation of the IL after fear conditioning would promote the extinction of conditioned fear. To test this hypothesis, we characterized the effects of post-conditioning infusions of the GABAA receptor antagonist, picrotoxin, into the IL on extinction of auditory conditioned freezing in male and female rats. In four experiments, we found that picrotoxin injections performed immediately, 24 hours, or 13 days after fear conditioning reduced conditioned freezing to the auditory conditioned stimulus (CS) during both extinction training and extinction retrieval; this effect was observed up to two weeks after picrotoxin infusions. Interestingly, inhibiting protein synthesis inhibition in the IL immediately after fear conditioning prevented the inhibition of freezing by picrotoxin injected 24 hours later. Our data suggest that the IL encodes an inhibitory memory during the consolidation of fear conditioning that is necessary for future fear suppression.

Systematic review of fNIRS studies reveals inconsistent chromophore data reporting practices.

Significance: Functional near-infrared spectroscopy (fNIRS) is unique among neuroimaging techniques in its ability to estimate changes in both oxyhemoglobin (HbO) and deoxyhemoglobin (HbR). However, fNIRS research has applied various data reporting practices based on these chromophores as measures of neural activation. Aim: To quantify the variability of fNIRS chromophore data reporting practices and to explore recent data reporting trends in the literature. Approach: We reviewed 660 fNIRS papers from 2015, 2018, and 2021 to extract information on fNIRS chromophore data reporting practices. Results: Our review revealed five general practices for reporting fNIRS chromophores: (1) HbO only, (2) HbR only, (3) HbO and HbR, (4) correlation-based signal improvement, and (5) either the total (HbT) or difference (HbDiff) in concentration between chromophores. The field was primarily divided between reporting HbO only and reporting HbO and HbR. However, reporting one chromophore (HbO) was consistently observed as the most popular data reporting practice for each year reviewed. Conclusions: Our results highlight the high heterogeneity of chromophore data reporting in fNIRS research. We discuss its potential implications for study comparison efforts and interpretation of results. Most importantly, our review demonstrates the need for a standard chromophore reporting practice to improve scientific transparency and, ultimately, to better understand how neural events relate to cognitive phenomena.

Discovery of a Covalent Inhibitor of KRASG12C (AMG 510) for the Treatment of Solid Tumors.

KRASG12C has emerged as a promising target in the treatment of solid tumors. Covalent inhibitors targeting the mutant cysteine-12 residue have been shown to disrupt signaling by this long-"undruggable" target; however clinically viable inhibitors have yet to be identified. Here, we report efforts to exploit a cryptic pocket (H95/Y96/Q99) we identified in KRASG12C to identify inhibitors suitable for clinical development. Structure-based design efforts leading to the identification of a novel quinazolinone scaffold are described, along with optimization efforts that overcame a configurational stability issue arising from restricted rotation about an axially chiral biaryl bond. Biopharmaceutical optimization of the resulting leads culminated in the identification of AMG 510, a highly potent, selective, and well-tolerated KRASG12C inhibitor currently in phase I clinical trials (NCT03600883).

Finite element analysis to investigate variability of MR elastography in the human thigh.

PURPOSE: To develop finite element analysis (FEA) of magnetic resonance elastography (MRE) in the human thigh and investigate inter-individual variability of measurement of muscle mechanical properties. METHODS: Segmentation was performed on MRI datasets of the human thigh from 5 individuals and FEA models consisting of 12 muscles and surrounding tissue created. The same material properties were applied to each tissue type and a previously developed transient FEA method of simulating MRE using Abaqus was performed at 4 frequencies. Synthetic noise was applied to the simulated data at various levels before inversion was performed using the Elastography Software Pipeline. Maps of material properties were created and visually assessed to determine key features. The coefficient of variation (CoV) was used to assess the variability of measurements in each individual muscle and in the groups of muscles across the subjects. Mean measurements for the set of muscles were ranked in size order and compared with the expected ranking. RESULTS: At noise levels of 2% the CoV in measurements of |G*| ranged from 5.3 to 21.9% and from 7.1 to 36.1% for measurements of ϕ in the individual muscles. A positive correlation (R2 value 0.80) was attained when the expected and measured |G*| ranking were compared, whilst a negative correlation (R2 value 0.43) was found for ϕ. CONCLUSIONS: Created elastograms demonstrated good definition of muscle structure and were robust to noise. Variability of measurements across the 5 subjects was dramatically lower for |G*| than it was for ϕ. This large variability in ϕ measurements was attributed to artefacts.

Effects of halogens on European air-quality.

Halogens (Cl, Br) have a profound influence on stratospheric ozone (O3). They (Cl, Br and I) have recently also been shown to impact the troposphere, notably by reducing the mixing ratios of O3 and OH. Their potential for impacting regional air-quality is less well understood. We explore the impact of halogens on regional pollutants (focussing on O3) with the European grid of the GEOS-Chem model (0.25° × 0.3125°). It has recently been updated to include a representation of halogen chemistry. We focus on the summer of 2015 during the ICOZA campaign at the Weybourne Atmospheric Observatory on the North Sea coast of the UK. Comparisons between these observations together with those from the UK air-quality network show that the model has some skill in representing the mixing ratios/concentration of pollutants during this period. Although the model has some success in simulating the Weybourne ClNO2 observations, it significantly underestimates ClNO2 observations reported at inland locations. It also underestimates mixing ratios of IO, OIO, I2 and BrO, but this may reflect the coastal nature of these observations. Model simulations, with and without halogens, highlight the processes by which halogens can impact O3. Throughout the domain O3 mixing ratios are reduced by halogens. In northern Europe this is due to a change in the background O3 advected into the region, whereas in southern Europe this is due to local chemistry driven by Mediterranean emissions. The proportion of hourly O3 above 50 nmol mol-1 in Europe is reduced from 46% to 18% by halogens. ClNO2 from N2O5 uptake onto sea-salt leads to increases in O3 mixing ratio, but these are smaller than the decreases caused by the bromine and iodine. 12% of ethane and 16% of acetone within the boundary layer is oxidised by Cl. Aerosol response to halogens is complex with small (∼10%) reductions in PM2.5 in most locations. A lack of observational constraints coupled to large uncertainties in emissions and chemical processing of halogens make these conclusions tentative at best. However, the results here point to the potential for halogen chemistry to influence air quality policy in Europe and other parts of the world.

The simulation of magnetic resonance elastography through atherosclerosis.

The clinical diagnosis of atherosclerosis via the measurement of stenosis size is widely acknowledged as an imperfect criterion. The vulnerability of an atherosclerotic plaque to rupture is associated with its mechanical properties. The potential to image these mechanical properties using magnetic resonance elastography (MRE) was investigated through synthetic datasets. An image of the steady state wave propagation, equivalent to the first harmonic, can be extracted directly from finite element analysis. Inversion of this displacement data yields a map of the shear modulus, known as an elastogram. The variation of plaque composition, stenosis size, Gaussian noise, filter thresholds and excitation frequency were explored. A decreasing mean shear modulus with an increasing lipid composition was identified through all stenosis sizes. However the inversion algorithm showed sensitivity to parameter variation leading to artefacts which disrupted both the elastograms and quantitative trends. As noise was increased up to a realistic level, the contrast was maintained between the fully fibrous and lipid plaques but lost between the interim compositions. Although incorporating a Butterworth filter improved the performance of the algorithm, restrictive filter thresholds resulted in a reduction of the sensitivity of the algorithm to composition and noise variation. Increasing the excitation frequency improved the techniques ability to image the magnitude of the shear modulus and identify a contrast between compositions. In conclusion, whilst the technique has the potential to image the shear modulus of atherosclerotic plaques, future research will require the integration of a heterogeneous inversion algorithm.

Hot topic: Early postpartum treatment of commercial dairy cows with nonsteroidal antiinflammatory drugs increases whole-lactation milk yield.

Previous research has shown that postpartum administration of the nonsteroidal antiinflammatory drug (NSAID) sodium salicylate can increase 305-d milk yield in older dairy cattle (parity 3 and greater). However, in this prior work, sodium salicylate was delivered to cows via the drinking water, a method that does not align well with current grouping strategies on commercial dairy farms. The objective of the current study was to replicate these results on a commercial dairy farm with a simplified treatment protocol and to compare sodium salicylate with another NSAID, meloxicam. Dairy cattle in their second lactation and greater (n=51/treatment) were alternately assigned to 1 of 3 treatments at parturition, with treatments lasting for 3d. Experimental treatments began 12 to 36 h after parturition and were (1) 1 placebo bolus on the first day and 3 consecutive daily drenches of sodium salicylate (125 g/cow per day; SAL); (2) 1 bolus of meloxicam (675 mg/cow) and 3 drenches of an equal volume of water (MEL); or (3) 1 placebo bolus and 3 drenches of water (CON). Blood samples were collected on the first day of treatment, immediately following the last day of treatment, and 7d after the last day of treatment; plasma was analyzed for glucose, ß-hydroxybutyrate (BHB), free fatty acids, haptoglobin, and paraoxonase. Milk production, body condition score, reproductive status, and retention in the herd were monitored for 365 d posttreatment, and effects of treatment, parity, days in milk, and interactions were evaluated in mixed effects models. Significance was declared at P<0.05. Whole-lactation milk and protein yields were greater in NSAID-treated cows, although 305-d fat production was not affected. There was a significant interaction of treatment and parity for plasma glucose concentration; MEL increased plasma glucose concentrations compared with CON and SAL in older cows. Sodium salicylate decreased plasma BHB concentration compared with MEL at 7d posttreatment, although no difference was detected immediately following treatment. Haptoglobin concentrations were elevated in SAL cows compared with CON. There was a tendency for CON cows to be removed from the herd more quickly than MEL cows (42 vs. 26% at 365 d posttreatment). Body condition score, concentrations of plasma free fatty acids and paraoxonase, and time to pregnancy were not affected by treatment. These results indicate that NSAID administration in postpartum cows has the potential to be a viable way to improve productivity and potentially longevity in commercial dairies, although further research is necessary to optimize recommendations for producers.

Sodium salicylate treatment in early lactation increases whole-lactation milk and milk fat yield in mature dairy cows.

Multiple lines of inquiry have suggested that a high degree of inflammation in early lactation cows is associated with low productivity and increased disease incidence. In addition, some small studies have suggested that milk production increases in response to antiinflammatory treatment in the first week of lactation. Our objective was to determine if administration of sodium salicylate (SS), a nonsteroidal antiinflammatory drug (NSAID), in the first week of lactation changes whole-lactation productivity and retention in the herd. At calving, 78 cows [n=39 primiparous (1P); n=24 second parity (2P); n=15 third parity or greater (3P)] were alternately assigned to either control (CON) or SS treatments for 7 d postpartum. Sodium salicylate treatment was administered via individual water bowls at a concentration of 1.95 g/L, delivering a mean of 123.3±5.5 g of salicylate/d during the 7-d treatment. For the first 21 d of lactation, dry matter intake, water intake, milk yield, and health were monitored daily, and milk samples were collected twice weekly for milk component analysis. Monthly milk yield and component testing through the rest of the lactation provided data to assess long-term responses, and the effects of treatment on the risk of leaving the herd and on 305-d milk, fat, and protein yields were assessed. During the first 21 d of lactation, we observed no differences in morbidity, except for increased risk of metritis in 3P SS cows. Treatment interacted with parity to influence both 305-d milk and milk fat yields, and a tendency for an interaction was detected for 305-d milk protein yield. Milk yield was 2,469±646 kg greater over the lactation in 3P SS cows compared with 3P CON cows (21% increase) and tended to decrease by 8% in 1P cows treated with SS; no effects were detected in 2P cows. Furthermore, 3P SS cows produced 130±23 kg more milk fat over the lactation (30% increase), with no effects detected for 1P or 2P. Treatment with SS tended to increase 305-d milk protein yield in 3P cows by 14%, with no effects in 1P or 2P cows. A tendency for a treatment × parity interaction was also observed for the risk of leaving the herd. First-parity cows treated with SS tended to have greater risk of leaving the herd than controls (30 vs. 6% risk); however, treatment did not alter herd retention in 2P or 3P groups, and SS had no effect on the risk of leaving the herd overall. Results indicate that SS has long-term effects on lactation of mature dairy cows, particularly on fat yield, but may have negative effects for primiparous cows.

Telepharmacy in a rural Alberta Community Cancer Network.

Telepharmacy services were developed and adopted to compensate for the absence of a pharmacist in rural Cancer Centers. Preparation included the formation of an advisory committee, development of a training and certification process, establishing new policies and operating procedures, collecting utilization data and a survey of patient and user satisfaction. Pharmacy technicians at two remote community cancer centers were connected by telehealth with pharmacists at one of the two coordinating centers to oversee the compounding of intravenous (I.V.) chemotherapy and provide clinical review of physician orders. In 8 months of telepharmacy use, 247 intravenous preparations were compounded for 47 cancer patients during 109 treatment visits. Approximately 45,000 km (27,000 miles) of patient travel were averted. Pharmacy staff estimates requires an average of 10 additional minutes to process and compound each chemotherapy preparation. Nurses estimate an average of 27.5 additional minutes required to coordinate information for each patient order.

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

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

Effects of distillers grains with high sulfur concentration on ruminal fermentation and digestibility of finishing diets.

Twelve ruminally cannulated crossbred Angus steers were used to evaluate ruminal fermentation characteristics and diet digestibility when 30% (DM) corn dried distillers grains with solubles (DDGS) containing 0.42 or 0.65% (DM) of dietary S was incorporated into finishing diets based on steam-flaked corn (SFC) or dry-rolled corn (DRC). The study was a replicated, balanced randomized incomplete block design with a 2 × 2 factorial arrangement of treatments. Factors consisted of dietary S concentration (0.42 and 0.65% of DM; 0.42S and 0.65S, respectively) and grain processing method (SFC or DRC). The 0.65S concentration was achieved by adding H(2)SO(4) to DDGS before mixing rations. Steers were assigned randomly to diets and individual, slatted-floor pens, and fed once daily for ad libitum intake. Two 15-d experimental periods were used, each consisting of a 12-d diet adaptation phase and a 3-d sample collection phase. Samples were collected at 2-h intervals postfeeding during the collection phase. Ruminal pH was measured immediately after sampling, and concentrations of ruminal ammonia and VFA were determined. Fecal samples were composited by steer within period and used to determine apparent total tract digestibilities of DM, OM, NDF, CP, starch, and ether extract. Feeding 0.65S tended (P = 0.08) to decrease DMI but resulted in greater apparent total tract digestibilities of DM (P = 0.04) and ether extract (P = 0.03). Ruminal pH increased (P < 0.05) in steers fed 0.65S diets, which may be attributable, in part, to decreased (P = 0.05) VFA concentrations and greater (P < 0.01) ruminal ammonia concentrations when 0.65S was fed, compared with feeding 0.42S. These effects were more exaggerated in steers fed DRC (interaction, P < 0.01), compared with steers fed SFC. Steers fed DRC-0.65S had greater (P < 0.01) acetate concentration than steers fed DRC-0.42S, but acetate concentration was not affected by S concentration when SFC was fed. Propionate concentration was decreased (P < 0.01) in steers fed SFC-0.65S compared with steers fed SFC-0.42S, but dietary S concentration had no effect on propionate concentration when DRC was fed. Butyrate concentration was less (P < 0.01) in steers fed 0.65S diets than in steers fed 0.42S. Lactate concentrations tended (P = 0.06) to decrease in steers fed 0.65S diets. Feeding DDGS with increased S concentration may decrease feed intake and ruminal VFA concentration but increase ruminal ammonia concentration.

Evaluation of sulfur content of dried distillers grains with solubles in finishing diets based on steam-flaked corn or dry-rolled corn.

Crossbred yearling steers (n=80; 406 ± 2.7 kg of BW) were used to evaluate the effects of S concentration in dried distillers grains with solubles (DDGS) on growth performance, carcass characteristics, and ruminal concentrations of CH(4) and H(2)S in finishing steers fed diets based on steam-flaked corn (SFC) or dry-rolled corn (DRC) and containing 30% DDGS (DM basis) with moderate S (0.42% S, MS) or high S (0.65% S, HS). Treatments consisted of SFC diets containing MS (SFC-MS), SFC diets containing HS (SFC-HS), DRC diets containing MS (DRC-MS), or DRC diets containing HS (DRC-HS). High S was achieved by adding H(2)SO(4) to DDGS. Ruminal gas samples were analyzed for concentrations of H(2)S and CH(4). Steers were fed once daily in quantities that resulted in traces of residual feed in the bunk the following day for 140 d. No interactions (P ≥ 0.15) between dietary S concentration and grain processing were observed with respect to growth performance or carcass characteristics. Steers fed HS diets had 8.9% less DMI (P < 0.001) and 12.9% less ADG (P=0.006) than steers fed diets with MS, but S concentration had no effect on G:F (P=0.25). Cattle fed HS yielded 4.3% lighter HCW (P = 0.006) and had 16.2% less KPH (P=0.009) than steers fed MS. Steers fed HS had decreased (P=0.04) yield grades compared with steers fed MS. No differences were observed among treatments with respect to dressing percentage, liver abscesses, 12th-rib fat thickness, LM area, or USDA quality grades (P ≥ 0.18). Steers fed SFC had less DMI (P < 0.001) than steers fed DRC. Grain processing had no effect (P > 0.05) on G:F or carcass characteristics. Cattle fed HS had greater (P < 0.001) ruminal concentrations of H(2)S than cattle fed MS. Hydrogen sulfide concentration was inversely related (P ≤ 0.01) to ADG (r=-0.58) and DMI (r=-0.67) in cattle fed SFC, and to DMI (r=-0.40) in cattle fed DRC. Feeding DDGS that are high in dietary S may decrease the DMI of beef steers and compromise the growth performance and carcass characteristics of feedlot cattle.

Bioactivation of isothiazoles: minimizing the risk of potential toxicity in drug discovery.

Compound 1, (7-methoxy-N-((6-(3-methylisothiazol-5-yl)-[1,2,4]triazolo[4,3-b]pyridazin-3-yl)methyl)-1,5-naphthyridin-4-amine) is a potent, selective inhibitor of c-Met (mesenchymal-epithelial transition factor), a receptor tyrosine kinase that is often deregulated in cancer. Compound 1 displayed desirable pharmacokinetic properties in multiple preclinical species. Glutathione trapping studies in liver microsomes resulted in the NADPH-dependent formation of a glutathione conjugate. Compound 1 also exhibited very high in vitro NADPH-dependent covalent binding to microsomal proteins. Species differences in covalent binding were observed, with the highest binding in rats, mice, and monkeys (1100-1300 pmol/mg/h), followed by dogs (400 pmol/mg/h) and humans (144 pmol/mg/h). This covalent binding to protein was abolished by coincubation with glutathione. Together, these in vitro data suggest that covalent binding and glutathione conjugation proceed via bioactivation to a chemically reactive intermediate. The cytochrome (CYP) P450 enzymes responsible for this bioactivation were identified as cytochrome P450 3A4, 1A2, and 2D6 in human and cytochrome P450 2A2, 3A1, and 3A2 in rats. The glutathione metabolite was detected in the bile of rats and mice, thus demonstrating bioactivation occurring in vivo. Efforts to elucidate the structure of the glutathione adduct led to the isolation and characterization of the metabolite by NMR and mass spectrometry. The analytical data confirmed conclusively that the glutathione conjugation was on the 4-C position of the isothiazole ring. Such P450-mediated bioactivation of an isothiazole or thiazole group has not been previously reported. We propose a mechanism of bioactivation via sulfur oxidation followed by glutathione attack at the 4-position with subsequent loss of water resulting in the formation of the glutathione conjugate. Efforts to reduce bioactivation without compromising potency and pharmacokinetics were undertaken in order to minimize the potential risk of toxicity. Because of the exemplary pharmacokinetic/pharmacodynamic (PK/PD) properties of the isothiazole group, initial attempts were focused on introducing alternative metabolic soft spots into the molecule. These efforts resulted in the discovery of 7-(2-methoxyethoxy)-N-((6-(3-methyl-5-isothiazolyl)[1,2,4]triazolo[4,3-b]pyridazin-3-yl)methyl)-1,5-naphthyridin-4-amine (compound 2), with the major metabolic transformation occurring on the naphthyridine ring alkoxy substituent. However, a glutathione conjugate of compound 2 was produced in vitro and in vivo in a manner similar to that observed for compound 1. Furthermore, the covalent binding was high across species (360, 300, 529, 208, and 98 pmol/mg/h in rats, mice, dogs, monkeys, and humans, respectively), but coincubation with glutathione reduced the extent of covalent binding. The second viable alternative in reducing bioactivation involved replacing the isothiazole ring with bioisosteric heterocycles. Replacement of the isothiazole ring with an isoxazole or a pyrazole reduced the bioactivation while retaining the desirable PK/PD characteristics of compounds 1 and 2.

Plasma pharmacokinetics of oral chlortetracycline in group fed, ruminating, Holstein steers in a feedlot setting.

Chlortetracycline HCl (CTC) has impacted profitable livestock production since 1945. However, pharmacokinetic parameters for CTC in ruminating cattle are unavailable in peer-reviewed literature. A total of 18 steers were randomized to 4.4, 11, or 22 mg/kg/day p.o. CTC treatment groups (n = 6). Chlortetracycline treatment was offered as one-half of the daily dose b.i.d. (160 total doses/group) for 80 days. Blood samples were collected at selected time points throughout an 83-day study and analyzed with a solid phase extraction technique and novel ultrahigh performance liquid chromatography-mass spectroscopy/mass spectroscopy analytical method. Noncompartmental analysis (NCA) determined individual pharmacokinetic parameters by treatment group with coefficient of variation (CV %) estimates. A one-compartment open model with first order absorption and elimination, where absorption rate constant was equal to elimination rate constant, was fitted using nonlinear mixed effects modeling (NLMEM). NLMEM determined the primary pharmacokinetic parameters: volume of distribution (V/F, 40.9 L/kg) and rate constant (k, 0.0478 h(-1)), and the secondary parameters: dose-normalized area under the curve (AUC/D, 0.29 h x microg/L), clearance (Cl/F, 1.8 L/kg/h), elimination half-life (t(1/2), 16.2 h), C(max/Dose) (4.5 ng/mL), and time of C(max) (T(max), 23.3 h) with improved CV estimates over NCA. Dose linearity was confirmed by anova of parameters derived from NCA by treatment group. Further studies are necessary for determining absolute bioavailability and pharmacokinetic-pharmacodynamic relationships of CTC in group fed, ruminating cattle.

Microbial translocation of needle-free versus traditional needle injection-enhanced beef strip loins.

Our objective was to determine the effects of needle-free (NF) versus needle injection (N) enhancement on microbial translocation of generic Escherichia coli in beef strip loins. Fifteen longissimus muscles (LM) were obtained and halved. Surfaces were inoculated with generic E. coli at a level of 10(6) CFU/cm(2) (three replications of five strip loins). LM halves were injection-enhanced with a phosphate and salt solution with either NF or N injection. After injection, two cores were taken from each LM half and sliced cross-sectionally at depths of 2-mm (surface), 1, 3, and 5 cm. The paired samples were stomached, serially diluted, and plated. Surface samples from N-injected muscles had lower (P<0.05) E. coli counts (2.79 versus 3.23 log CFU/g for NF). Also, the 3- and 5-cm depth samples from N injection had the least (P<0.05) E. coli contamination (1.69 versus 2.12 CFU/g for NF). Although traditional N injection resulted in approximately 0.5 log CFU/g less microbial contamination at all depths, because the level of contamination was extremely high, the difference in the treatments could arguably be of little practical importance in terms of safety.

A comparison of needle-free and needle-injection methods and solutions for enhancement of beef longissimus lumborum muscles.

In Experiment 1, beef strip loins (n=15) were halved and assigned to needle (N) or needle-free (NF) injection enhancement with a phosphate plus salt solution (PS) to determine effects on color, water-binding, and palatability. Pump yields tended (P=0.08) to be higher for NF injection. Needle-injected steaks were darker (P<0.05) on day 1 only. The NF treatment had greater instrumental tenderness and intensity of off-flavors but less cooking loss and beef flavor (both P<0.05). In Experiment 2, strip loins (n=28) were halved and assigned to one of four treatments: (1) N, or (2) NF injection with PS; (3) N, or (4) NF injection with a calcium lactate solution (CL) to determine effects on water-binding and palatability. Needle-free injection resulted in a greater incidence (P<0.05) of off-flavors and abnormal texture. The PS solution resulted in greater (P<0.05) instrumental, myofibrillar, and overall tenderness; greater juiciness; greater incidence of off-flavors and abnormal texture; and less (P<0.05) connective tissue and cooking losses than CL. The PS and NF combination had the highest pumped yields and least cooking losses (both P<0.05). Enhancing beef strip loins with PS and NF injection has potential to improve yield, tenderness, and juiciness but harm texture and flavor.

Metastatic Crohn's disease of the ear.

Objective. We reported a very rare case of metastatic Crohn's disease involving the retro-auricular region. Method. A case report and a review of literature concerning metastatic Crohn's disease. Results. Metastatic Crohn's disease is an uncommon extraintestinal cutaneous manifestation of Crohn's disease and a very rare case involving the retro-auricular region is reported here. Given the limited existing literature little is known about this condition. The skin lesions appear to have a predilection for the lower trunk and genitalia regions. There is no clear association with the severity of Crohn's disease and in some cases, the cutaneous lesions predate the onset of gastrointestinal Crohn's disease. Treatment with immune-modulating medications together with the antitumour necrosis factor monoclonal antibody therapy appears to offer the best chance of remission. Conclusion. By reporting this interesting and rare condition we also hope to highlight the importance of considering underlying chronic systemic disorders, such as Crohn's disease, when presented with skin lesions resistant to simple local treatments.

What is in a name--patients' view of the involvement of 'care practitioners' in their operations.

BACKGROUND: There has been a plethora of new job titles emerging in the NHS. While the term 'nurse practitioner' was fairly well received, and offers a pretty clear indication of the background of the person working, other new titles can be misleading. Since 2003, when the NHS Modernisation Agency proposed its 'Changing Workforce Programme', nurses and other allied health professionals were recruited and trained to perform 'simple operations'. The surgical care practitioner is being developed along with other practitioners. OBJECTIVE: To find out whether patients are able to identify healthcare professionals by their title and what do patients think about a non-medically qualified person carrying out their operations. METHODS: A cross-sectional survey of ENT patients using a questionnaire. MAIN FINDINGS: Titles similar to those of medically qualified professionals--anaesthetic practitioner, consultant nurse and surgical care practitioners--can lead patients to think that they are doctors. Fifty-three per cent of the respondents agreed that not all hospital visits need to be attended by a doctor, but if an operation is needed, 92% of respondents thought it should be carried out by someone who is medically trained. Ninety-four per cent stated that they should be informed if this is not the case. Seventy-nine per cent of the respondents stated that they would rather wait longer to be operated on by a doctor than being operated on earlier by someone who is not medically qualified but trained to perform the operation only. This result is significant, p<0.001). CONCLUSION: Patients do find the different titles confusing, with many preferring a more transparent approach in knowing who their surgeon is. The majority would prefer to wait longer for their operation if this means it is carried out by a doctor.

Chemical reactivity of methoxy 4-o-aryl quinolines: identification of glutathione displacement products in vitro and in vivo.

AMG 458 {1-(2-hydroxy-2-methylpropyl)-N-[5-(7-methoxyquinolin-4-yloxy)pyridin-2-yl]-5-methyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazole-4-carboxamide} is a potent, selective inhibitor of c-Met, a receptor tyrosine kinase that is often deregulated in cancer. AMG 458 was observed to bind covalently to liver microsomal proteins from rats and humans in the absence of NADPH. When [(14)C]AMG 458 was incubated with liver microsomes in the presence of glutathione and N-acetyl cysteine, thioether adducts were detected by radiochromatography and LC/MS/MS analysis. These adducts were also formed upon incubation of AMG 458 with glutathione and N-acetyl cysteine in buffers at pH 7.4. In vivo, the thioether adducts were detected in bile and urine of bile duct-cannulated rats dosed with [(14)C]AMG 458. The two adducts were isolated, and their structures were determined by MS/MS and NMR analysis. The identified structures resulted from a thiol displacement reaction to yield a quinoline thioether structure and the corresponding hydroxyaryl moiety. The insights gained from elucidating the mechanism of adduct formation led to the design of AMG 458 analogues that exhibited eliminated or reduced glutathione adduct formation in vitro and in vivo.