Large offspring syndrome in cattle and sheep

Bovine and ovine embryos exposed to a variety of unusual environments prior to the blastocyst stage have resulted in the development of unusually large offspring which can also exhibit a number of organ defects. In these animals, the increased incidence of difficult parturition and of fetal and neonatal losses has limited the large-scale use of in vitro embryo production technologies commonly used in humans and other species. Four different situations have been identified that result in the syndrome: in vitro embryo culture, asynchronous embryo transfer into an advanced uterine environment, nuclear transfer and maternal exposure to excessively high urea diets. However, programming of the syndrome by all of these situations is unpredictable and not all of the symptoms described have been observed universally. Neither the environmental factors inducing the large offspring syndrome nor the mechanisms of perturbation occurring in the early embryo and manifesting themselves in the fetus have been identified.

Tooth bleaching--a critical review of the biological aspects

Present tooth-bleaching techniques are based upon hydrogen peroxide as the active agent. It is applied directly, or produced in a chemical reaction from sodium perborate or carbamide peroxide. More than 90% immediate success has been reported for intracoronal bleaching of non-vital teeth, and in the period of 1-8 years' observation time, from 10 to 40% of the initially successfully treated teeth needed re-treatment. Cervical root resorption is a possible consequence of internal bleaching and is more frequently observed in teeth treated with the thermo-catalytic procedure. When the external tooth-bleaching technique is used, the first subjective change in tooth color may be observed after 2-4 nights of tooth bleaching, and more than 90% satisfactory results have been reported. Tooth sensitivity is a common side-effect of external tooth bleaching observed in 15%-78% of the patients, but clinical studies addressing the risk of other adverse effects are lacking. Direct contact with hydrogen peroxide induced genotoxic effects in bacteria and cultured cells, whereas the effect was reduced or abolished in the presence of metabolizing enzymes. Several tumor-promoting studies, including the hamster cheek pouch model, indicated that hydrogen peroxide might act as a promoter. Multiple exposures of hydrogen peroxide have resulted in localized effects on the gastric mucosa, decreased food consumption, reduced weight gain, and blood chemistry changes in mice and rats. Our risk assessment revealed that a sufficient safety level was not reached in certain clinical situations of external tooth bleaching, such as bleaching one tooth arch with 35% carbamide peroxide, using several applications per day of 22% carbamide peroxide, and bleaching both arches simultaneously with 22% carbamide peroxide. The recommendation is to avoid using concentrations higher than 10% carbamide peroxide when one performs external bleaching. We advocate a selective use of external tooth bleaching based on high ethical standards and professional judgment.

The effects of the cardiac myosin activator, omecamtiv mecarbil, on cardiac function in systolic heart failure: a double-blind, placebo-controlled, crossover, dose-ranging phase 2 trial

BACKGROUND

Many patients with heart failure remain symptomatic and have a poor prognosis despite existing treatments. Decreases in myocardial contractility and shortening of ventricular systole are characteristic of systolic heart failure and might be improved by a new therapeutic class, cardiac myosin activators. We report the first study of the cardiac myosin activator, omecamtiv mecarbil, in patients with systolic heart failure.

METHODS

We undertook a double-blind, placebo-controlled, crossover, dose-ranging, phase 2 trial investigating the effects of omecamtiv mecarbil (formerly CK-1827452), given intravenously for 2, 24, or 72 h to patients with stable heart failure and left ventricular systolic dysfunction receiving guideline-indicated treatment. Clinical assessment (including vital signs, echocardiograms, and electrocardiographs) and testing of plasma drug concentrations took place during and after completion of each infusion. The primary aim was to assess safety and tolerability of omecamtiv mecarbil. This study is registered at ClinicalTrials.gov, NCT00624442.

FINDINGS

45 patients received 151 infusions of active drug or placebo. Placebo-corrected, concentration-dependent increases in left ventricular ejection time (up to an 80 ms increase from baseline) and stroke volume (up to 9·7 mL) were recorded, associated with a small reduction in heart rate (up to 2·7 beats per min; p<0·0001 for all three measures). Higher plasma concentrations were also associated with reductions in end-systolic (decrease of 15 mL at >500 ng/mL, p=0·0026) and end-diastolic volumes (16 mL, p=0·0096) that might have been more pronounced with increased duration of infusion. Cardiac ischaemia emerged at high plasma concentrations (two patients, plasma concentrations roughly 1750 ng/mL and 1350 ng/mL). For patients tolerant of all study drug infusions, no consistent pattern of adverse events with either dose or duration emerged.

INTERPRETATION

Omecamtiv mecarbil improved cardiac function in patients with heart failure caused by left ventricular dysfunction and could be the first in class of a new therapeutic agent.

FUNDING

Cytokinetics Inc.

A selective orexin-1 receptor antagonist reduces food consumption in male and female rats

A variety of evidence implicates the orexins, especially orexin-A, in the regulation of food intake, but it has not been established whether this effect is mediated by the orexin-1 or orexin-2 receptor. In the present study, a selective orexin-1 receptor antagonist, 1-(2-methylbenzoxazol-6-yl)-3-[1,5]naphthyridin-4-yl urea hydrochloride (SB-334867-A), was administered intraperitoneally to rats under various conditions, and food consumption was subsequently measured over 24 h. In male rats, a single dose of SB-334867-A (30 mg/kg, i.p.) given during the light phase reduced both orexin-A-induced food intake (7 nmol, i.c.v.) and feeding stimulated by an overnight fast for 4 h. When given at the start of the dark phase, food consumption was reduced in both male and female rats over 24 h. Daily injections at the start of the dark phase for 3 days reduced natural feeding in male rats over 24 h on days one and three. These findings demonstrate direct inhibition of orexin-A induced food intake with a selective orexin-1 receptor antagonist. Furthermore, the suppression of nocturnal feeding and food intake stimulated by an overnight fast supports other evidence that orexin-A is involved in the regulation of natural feeding and suggests that orexin-1 receptor antagonists could be useful in the treatment of obesity.

Essential amino acids and muscle protein recovery from resistance exercise

This study tests the hypothesis that a dose of 6 g of orally administered essential amino acids (EAAs) stimulates net muscle protein balance in healthy volunteers when consumed 1 and 2 h after resistance exercise. Subjects received a primed constant infusion of L-[(2)H(5)]phenylalanine and L-[1-(13)C]leucine. Samples from femoral artery and vein and biopsies from vastus lateralis were obtained. Arterial EAA concentrations increased severalfold after drinks. Net muscle protein balance (NB) increased proportionally more than arterial AA concentrations in response to drinks, and it returned rapidly to basal values when AA concentrations decreased. Area under the curve for net phenylalanine uptake above basal value was similar for the first hour after each drink (67 +/- 17 vs. 77 +/- 20 mg/leg, respectively). Because the NB response was double the response to two doses of a mixture of 3 g of EAA + 3 g of nonessential AA (NEAA) (14), we conclude that NEAA are not necessary for stimulation of NB and that there is a dose-dependent effect of EAA ingestion on muscle protein synthesis.

Chronic Oral Study of Myosin Activation to Increase Contractility in Heart Failure (COSMIC-HF): a phase 2, pharmacokinetic, randomised, placebo-controlled trial

BACKGROUND

Impaired contractility is a feature of heart failure with reduced ejection fraction. We assessed the pharmacokinetics and effects on cardiac function and structure of the cardiac myosin activator, omecamtiv mecarbil.

METHODS

In this randomised, double-blind study, done at 87 sites in 13 countries, we recruited patients with stable, symptomatic chronic heart failure and left ventricular ejection fraction 40% or lower. Patients were randomly assigned equally, via an interactive web response system, to receive 25 mg oral omecamtiv mecarbil twice daily (fixed-dose group), 25 mg twice daily titrated to 50 mg twice daily guided by pharmacokinetics (pharmacokinetic-titration group), or placebo for 20 weeks. We assessed the maximum concentration of omecamtiv mecarbil in plasma (primary endpoint) and changes in cardiac function and ventricular diameters. This trial is registered with ClinicalTrials.gov, number NCT01786512.

FINDINGS

From March 17, 2014, to March 5, 2015, we enrolled 150 patients in the fixed-dose omecamtiv mecarbil group and 149 in the pharmacokinetic-titration and placebo groups. Mean maximum concentration of omecamtiv mecarbil at 12 weeks was 200 (SD 71) ng/mL in the fixed-dose group and 318 (129) ng/mL in the pharmacokinetic-titration group. For the pharmacokinetic-titration group versus placebo group at 20 weeks, least square mean differences were as follows: systolic ejection time 25 ms (95% CI 18-32, p<0·0001), stroke volume 3·6 mL (0·5-6·7, p=0·0217), left ventricular end-systolic diameter -1·8 mm (-2·9 to -0·6, p=0·0027), left ventricular end-diastolic diameter -1·3 mm, (-2·3 to 0·3, p=0·0128), heart rate -3·0 beats per min (-5·1 to -0·8, p=0·0070), and N-terminal pro B-type natriuretic peptide concentration in plasma -970 pg/mL (-1672 to -268, p=0·0069). The frequency of adverse clinical events did not differ between groups.

INTERPRETATION

Omecamtiv mecarbil dosing guided by pharmacokinetics achieved plasma concentrations associated with improved cardiac function and decreased ventricular diameter.

FUNDING

Amgen.

Dose-dependent augmentation of cardiac systolic function with the selective cardiac myosin activator, omecamtiv mecarbil: a first-in-man study

BACKGROUND

Decreased systolic function is central to the pathogenesis of heart failure in millions of patients worldwide, but mechanism-related adverse effects restrict existing inotropic treatments. This study tested the hypothesis that omecamtiv mecarbil, a selective cardiac myosin activator, will augment cardiac function in human beings.

METHODS

In this dose-escalating, crossover study, 34 healthy men received a 6-h double-blind intravenous infusion of omecamtiv mecarbil or placebo once a week for 4 weeks. Each sequence consisted of three ascending omecamtiv mecarbil doses (ranging from 0·005 to 1·0 mg/kg per h) with a placebo infusion randomised into the sequence. Vital signs, blood samples, electrocardiographs (ECGs), and echocardiograms were obtained before, during, and after each infusion. The primary aim was to establish maximum tolerated dose (the highest infusion rate tolerated by at least eight participants) and plasma concentrations of omecamtiv mecarbil; secondary aims were evaluation of pharmacodynamic and pharmacokinetic characteristics, safety, and tolerability. This study is registered at ClinicalTrials.gov, number NCT01380223.

FINDINGS

The maximum tolerated dose of omecamtiv mecarbil was 0·5 mg/kg per h. Omecamtiv mecarbil infusion resulted in dose-related and concentration-related increases in systolic ejection time (mean increase from baseline at maximum tolerated dose, 85 [SD 5] ms), the most sensitive indicator of drug effect (r(2)=0·99 by dose), associated with increases in stroke volume (15 [2] mL), fractional shortening (8% [1]), and ejection fraction (7% [1]; all p<0·0001). Omecamtiv mecarbil increased atrial contractile function, and there were no clinically relevant changes in diastolic function. There were no clinically significant dose-related adverse effects on vital signs, serum chemistries, ECGs, or adverse events up to a dose of 0·625 mg/kg per h. The dose-limiting toxic effect was myocardial ischaemia due to excessive prolongation of systolic ejection time.

INTERPRETATION

These first-in-man data show highly dose-dependent augmentation of left ventricular systolic function in response to omecamtiv mecarbil and support potential clinical use of the drug in patients with heart failure.

FUNDING

Cytokinetics Inc.

The effects of the TRPV1 antagonist SB-705498 on TRPV1 receptor-mediated activity and inflammatory hyperalgesia in humans

TRPV1 is a cation channel activated by a range of noxious stimuli and highly expressed in nociceptive fibres. TRPV1 receptors are involved in pain and sensitisation associated with tissue injury and inflammation; hence, TRPV1 antagonists are potentially useful for the treatment of such pain states. SB-705498 is a potent, selective and orally bioavailable TRPV1 antagonist with demonstrated efficacy in a number of preclinical pain models. In this first-time-into-human study, we have investigated the pharmacodynamic and antihyperalgesic activity of SB-705498. The compound was safe and well tolerated at single oral doses up to 400mg. In a cohort of 19 healthy volunteers, we used a randomised placebo-controlled single-blind cross-over design to assess the effects of SB-705498 (400mg) on heat-evoked pain and skin sensitisation induced by capsaicin or UVB irradiation. Compared with placebo, SB-705498 reduced the area of capsaicin-evoked flare (P=0.0047). The heat pain threshold on non-sensitised skin was elevated following SB-705498 (estimated difference from placebo [95% confidence intervals]: 1.3 degrees C [0.07,2.53], P=0.019). Following capsaicin sensitisation, the heat pain threshold and tolerance were similar between SB-705498 and placebo. However, SB-705498 increased heat pain tolerance at the site of UVB-evoked inflammation (estimated difference from placebo: 0.93 degrees C [0.25,1.6], P=0.0054). The magnitude of the pharmacodynamic effects of SB-705498 appeared to be related to plasma concentration. These results indicate that SB-705498, at a clinically safe and well-tolerated dose, has target-specific pharmacodynamic activity in humans. These data provide the first clinical evidence that a TRPV1 antagonist may alleviate pain and hyperalgesia associated with inflammation and tissue injury.

Enhancement of antinociception by coadministration of nonsteroidal anti-inflammatory drugs and soluble epoxide hydrolase inhibitors

Combination therapies have long been used to treat inflammation while reducing side effects. The present study was designed to evaluate the therapeutic potential of combination treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) and previously undescribed soluble epoxide hydrolase inhibitors (sEHIs) in lipopolysaccharide (LPS)-challenged mice. NSAIDs inhibit cyclooxygenase (COX) enzymes and thereby decrease production of metabolites that lead to pain and inflammation. The sEHIs, such as 12-(3-adamantan-1-yl-ureido)-dodecanoic acid butyl ester (AUDA-BE), stabilize anti-inflammatory epoxy-eicosatrienoic acids, which indirectly reduce the expression of COX-2 protein. Here we demonstrate that the combination therapy of NSAIDs and sEHIs produces significantly beneficial effects that are additive for alleviating pain and enhanced effects in reducing COX-2 protein expression and shifting oxylipin metabolomic profiles. When administered alone, AUDA-BE decreased protein expression of COX-2 to 73 +/- 6% of control mice treated with LPS only without altering COX-1 expression and decreased PGE(2) levels to 52 +/- 8% compared with LPS-treated mice not receiving any therapeutic intervention. When AUDA-BE was used in combination with low doses of indomethacin, celecoxib, or rofecoxib, PGE(2) concentrations dropped to 51 +/- 7, 84 +/- 9, and 91 +/- 8%, respectively, versus LPS control, without disrupting prostacyclin and thromboxane levels. These data suggest that these drug combinations (NSAIDs and sEHIs) produce a valuable beneficial analgesic and anti-inflammatory effect while prospectively decreasing side effects such as cardiovascular toxicity.

An atomic force microscopy study on the effect of bleaching agents on enamel surface

OBJECTIVES

The aim of the present study was to evaluate the effect of three peroxide-containing bleaching agents, Opalescence, Nite White and a 30% hydrogen peroxide solution, on enamel surfaces using Atomic Force Microscopy (AFM).

METHODS

Fifteen non-carious human incisors (ten maxillary and five mandibular, extracted for periodontal reasons) were used. The teeth were divided randomly into three groups of five, according to the bleaching agents. The labial surface of each tooth was imaged by AFM before and after treatment. Each bleaching agent was applied for a total of 28 h (in individual 4 h treatments). The specimens were examined only after 28 h of treatment.

RESULTS

On comparing the AFM images of untreated and treated enamel, surface alterations were observed after 28 h of treatment with Opalescence, Nite White and 30% hydrogen peroxide solution. Several grooves present in the enamel surface of untreated teeth became deeper after the bleaching procedure. The depths of the grooves increased in each case. The increase in the depth of grooves was more pronounced in the case of the 30% H2O2 solution.

CONCLUSION

Home-use bleaching agents are capable of causing enamel surface alterations. It is hypothesized that the peroxide-containing bleaching agents affect the organic phase of enamel. Peroxides can affect not only the surface but also the inner structure of enamel. As a result of its low molecular weight, hydrogen peroxide can penetrate into the enamel. Thus, inner oxidative effects are more likely to occur in the subsurface enamel where more organic material is present and oxidation is capable of altering the outer enamel and the surface.

Dietary excesses of urea influence the viability and metabolism of preimplantation sheep embryos and may affect fetal growth among survivors

In the first of two experiments investigating the effect of dietary urea on the survival and metabolism of ovine embryos, 30 Border Leicester x Scottish Blackface ewes received a maintenance diet (milled hay, molasses, minerals, vitamins) with no urea (control, C; n = 10) or with added urea at 15 g (low urea, LU; n = 10) or 30 g (high urea, HU; n = 10) kg-1 feed for a 12 week period. The degraded nitrogen (N) status relative to estimated rumen microbial N requirements was -2, +9 and +20 g per day, respectively. One week after allocation to diets, progesterone priming (12 days) commenced. Ewes received 800 IU of equine chorionic gonadotrophin at progesterone withdrawal, were inseminated 52 h later (Day 0) and embryos were collected from five ewes per group at Day 4 and from five ewes at Day 11. If available, one embryo was returned to each ewe; the rest were cultured in vitro. There was no effect of treatment on progesterone, luteinizing hormone (LH), or time of oestrus onset C, LU and HU plasma urea (P < 0.001) and ammonia levels (C vs. HU, P < 0.01; LU vs. HU, P < 0.05) differed. Day 4 HU embryos were retarded relative to C and LU embryos. After 3 days of culture, 70%, 66% and 0% of C, LU and HU embryos, respectively, were viable. Mid-term pregnancy rates following transfer were 63%, 43% and 33%. Only one HU lamb (male) was born following embryo transfer, its birthweight (10.1 kg) exceeded that of its C (n = 3; 7.0, 7.0, 7.5 kg) and LU (n = 2; 7.3, 8.2 kg) counterparts (P < 0.025). In the second experiment, C2 (2.5 g urea kg-1; n = 5) and HU2 (30 g kg-1; n = 7) diets which provided similar intakes of degraded N relative to microbial requirements as those for C and HU ewes in Experiment 1 were fed to Border Leicester x Scottish Blackface ewes superovulated with 16 mg of porcine follicle-stimulating hormone. Urea and ammonia levels in utero-oviductal samples were elevated in HU2 ewes (P < 0.05). At collection (Day 3), HU2 embryos used more glucose (P < 0.01) and, following culture, some exhibited up to a 2.8-fold increase in metabolism. In conclusion, excess rumen degradable N in ewe diets elevates urea and ammonia in plasma and in utero, with an associated increase in embryo mortality. Nevertheless, metabolism appears to be up-regulated in some embryos and, among those that survive, fetal growth appears to be enhanced.

A Trial of Short Incubation, Broad-Area Photodynamic Therapy for Facial Actinic Keratoses and Diffuse Photodamage

BACKGROUND

There is no completely satisfactory treatment for multiple actinic keratoses (AKs).

OBJECTIVE

To evaluate the efficacy of short incubation, broad-area application of delta-aminolevulinic acid followed by exposure to activating light-photodynamic therapy (delta-ALA/PDT) for treatment of AKs and background photodamage. The benefit of pretreatment with 40% urea cream to enhance penetration and the use of topical 3% lidocaine hydrochloride to decrease discomfort were also evaluated.

METHODS

Eighteen patients with at least 4 nonhypertrophic facial AKs and mild to moderate diffuse facial photodamage were enrolled in the study. For 7 days, 40% urea cream or vehicle was applied to half of the treatment area, and then delta-ALA was applied to the entire area for 1, 2, or 3 hours. Lidocaine hydrochloride (3%) or vehicle cream was also applied to the entire area 45 minutes before exposure to 10 J/cm(2) of blue light. Pain,phototoxic reactions, AK counts, and photodamage improvement were evaluated 1 day, 1 week, and 1 month after treatment in all patients and after 5 months in 10 patients.

RESULTS

All patients experienced mild to moderate discomfort during treatment and moderate phototoxic effects for 1 week. At 1 and 5 months there was significant reduction in AKs in all groups and significant improvement of several photodamage parameters. Different delta-ALA application times and pretreatment with urea cream or lidocaine had no significant effect on the results.

CONCLUSIONS

This delta-ALA/PDT protocol is safe and effective for AK treatment as well as for improving photodamage. Further studies with a larger cohort, longer follow-up, and histologic confirmation of the clinical data would be of value.

Phase I dose-escalation study of AZD7762, a checkpoint kinase inhibitor, in combination with gemcitabine in US patients with advanced solid tumors

PURPOSE

AZD7762 is a Chk1 kinase inhibitor which increases sensitivity to DNA-damaging agents, including gemcitabine. We evaluated the safety of AZD7762 monotherapy and with gemcitabine in advanced solid tumor patients.

EXPERIMENTAL DESIGN

In this Phase I study, patients received intravenous AZD7762 on days 1 and 8 of a 14-day run-in cycle (cycle 0; AZD7762 monotherapy), followed by AZD7762 plus gemcitabine 750-1,000 mg/m(2) on days 1 and 8, every 21 days, in ascending AZD7762 doses (cycle 1; combination therapy).

RESULTS

Forty-two patients received AZD7762 6 mg (n = 9), 9 mg (n = 3), 14 mg (n = 6), 21 mg (n = 3), 30 mg (n = 7), 32 mg (n = 6), and 40 mg (n = 8), in combination with gemcitabine. Common adverse events (AEs) were fatigue [41 % (17/42) patients], neutropenia/leukopenia [36 % (15/42) patients], anemia/Hb decrease [29 % (12/42) patients] and nausea, pyrexia and alanine aminotransferase/aspartate aminotransferase increase [26 % (11/42) patients each]. Grade ≥3 AEs occurred in 19 and 52 % of patients in cycles 0 and 1, respectively. Cardiac dose-limiting toxicities occurred in two patients (both AZD7762 monotherapy): grade 3 troponin I increase (32 mg) and grade 3 myocardial ischemia with chest pain, electrocardiogram changes, decreased left ventricular ejection fraction, and increased troponin I (40 mg). AZD7762 exposure increased linearly. Gemcitabine did not affect AZD7762 pharmacokinetics. Two non-small-cell lung cancer patients achieved partial tumor responses (AZD7762 6 mg/gemcitabine 750 mg/m(2) and AZD7762 9 mg cohort).

CONCLUSIONS

The maximum-tolerated dose of AZD7762 in combination with gemcitabine 1,000 mg/m(2) was 30 mg. Although development of AZD7762 is not going forward owing to unpredictable cardiac toxicity, Chk1 remains an important therapeutic target.

Aberrant nuclear accumulation of glycogen synthase kinase-3beta in human pancreatic cancer: association with kinase activity and tumor dedifferentiation

PURPOSE

We have shown recently that glycogen synthase kinase-3 (GSK-3) beta regulates nuclear factor-kappaB (NF-kappaB)-mediated pancreatic cancer cell survival and proliferation in vitro. Our objective was to determine the localization of GSK-3beta in pancreatic cancer cells and assess the antitumor effect of GSK-3 inhibition in vivo to improve our understanding of the mechanism by which GSK-3beta affects NF-kappaB activity in pancreatic cancer.

EXPERIMENTAL DESIGN

Immunohistochemistry and cytosolic/nuclear fractionation were done to determine the localization of GSK-3beta in human pancreatic tumors. We studied the effect of GSK-3 inhibition on tumor growth, cancer cell proliferation, and survival in established CAPAN2 tumor xenografts using a tumor regrowth delay assay, Western blotting, bromodeoxyuridine incorporation, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling.

RESULTS

We found nuclear accumulation of GSK-3beta in pancreatic cancer cell lines and in 62 of 122 (51%) human pancreatic adenocarcinomas. GSK-3beta nuclear accumulation is significantly correlated with human pancreatic cancer dedifferentiation. We have found that active GSK-3beta can accumulate in the nucleus of pancreatic cancer cells and that inhibition of GSK-3 kinase activity represses its nuclear accumulation via proteasomal degradation within the nucleus. Lastly, we have found that inhibition of GSK-3 arrests pancreatic tumor growth in vivo and decreases NF-kappaB-mediated pancreatic cancer cell survival and proliferation in established tumor xenografts.

CONCLUSIONS

Our results show the antitumor effect of GSK-3 inhibition in vivo, identify GSK-3beta nuclear accumulation as a hallmark of poorly differentiated pancreatic adenocarcinoma, and provide new insight into the mechanism by which GSK-3beta regulates NF-kappaB activity in pancreatic cancer.

Catabolism of heme in vivo: comparison of the simultaneous production of bilirubin and carbon monoxide

The quantitative relationship between the catabolism of heme and the formation of bilirubin and carbon monoxide (CO) was studied in untreated rats and in animals treated with phenobarbital or the porphyrogenic drug, allylisopropylacetamide (AIA). A novel metabolic chamber permitting continuous collection of the bile and breath was utilized for quantitation of bilirubin-(14)C and (14)CO after the administration of hematin-(14)C or glycine-(14)C. After intravenous infusion of hematin-(14)C, control and phenobarbital-treated rats produced equimolar amounts of labeled bilirubin and CO; a minor fraction of the infused radioactivity appeared in the bile in other metabolites. The equimolar relationship in the formation of bilirubin and CO was also observed after pulse-labeling with glycine-2-(14)C; in phenobarbital-treated rats both metabolites were formed at an increased rate as compared to controls. By contrast, AIA treatment reduced the fractional conversion of hematin-(14)C to bilirubin and CO; a major fraction of the infused radioactivity appeared in the bile in metabolites other than bilirubin. In addition, in AIA-treated animals the molar CO/bilirubin recovery ratio was consistently greater than 1.0. Comparable results were obtained in AIA-treated rats after pulse-labeling with glycine-2-(14)C. These findings suggest that (a) in control and phenobarbital-treated rats infused hematin and heme formed in the liver are converted predominantly to bilirubin and CO, appearing in equimolar amounts; only a minor fraction of the hematin is degraded to other metabolites; (b) treatment with phenobarbital results in a proportional increase in the formation of both bilirubin and CO, reflecting increased heme synthesis and degradation in the liver; and (c) treatment with the porphyrogenic drug AIA shifts the CO/bilirubin ratio in favor of the gas, and enhances the formation of nonbilirubin metabolites.

Efficacy and safety of a fatty acid amide hydrolase inhibitor (PF-04457845) in the treatment of cannabis withdrawal and dependence in men: a double-blind, placebo-controlled, parallel group, phase 2a single-site randomised controlled trial

BACKGROUND

Cannabis is one of the most widely used drugs worldwide. Cannabis use disorder is characterised by recurrent use of cannabis that causes significant clinical and functional impairment. There are no approved pharmacological treatments for cannabis use disorder. One approach is to potentiate endocannabinoid signalling by inhibiting fatty acid amide hydrolase (FAAH), the enzyme that degrades the endocannabinoid anandamide. We aimed to test the efficacy and safety of the FAAH-inhibitor PF-04457845 in reduction of cannabis withdrawal and cannabis use in men who were daily cannabis users.

METHODS

We did a double-blind, placebo-controlled, parallel group phase 2a trial at one site in men aged 18-55 years with cannabis dependence according to DSM-IV criteria (equivalent to cannabis use disorder in DSM-5). After baseline assessments, participants were randomly assigned (2:1) to receive PF-04457845 (4 mg per day) or placebo using a fixed block size of six participants, stratified by severity of cannabis use and desire to quit. Participants were admitted to hospital for 5 days (maximum 8 days) to achieve abstinence and precipitate cannabis withdrawal, after which they were discharged to continue the remaining 3 weeks of treatment as outpatients. The primary endpoints were treatment-related differences in cannabis withdrawal symptoms during hospital admission, and week 4 (end of treatment) self-reported cannabis use and urine THC-COOH concentrations in the intention-to-treat population. The study is registered at ClinicalTrials.gov, number NCT01618656.

FINDINGS

Between Sept 12, 2012, and Jan 18, 2016, 46 men were randomly assigned to PF-04457845 and 24 to placebo. Adherence to study medication was 88%, as confirmed by video-calling and pill count, and corroborated by corresponding drug and anandamide concentrations in blood. Relative to placebo, treatment with PF-04457845 was associated with reduced symptoms of cannabis withdrawal (first day of treatment mean symptom score 11·00 [95% CI 7·78-15·57] vs 6·04 [4·43-8·24]; difference 4·96 [0·71-9·21]; padj=0·048; second day of treatment 11·74 [8·28-16·66] vs 6·02 [4·28-8·47]; difference 5·73 [1·13-10·32]; padj=0·035) and related mood symptoms during the inpatient phase. Additionally, treatment with PF-04457845 was associated with lower self-reported cannabis use at 4 weeks (mean 1·27 joints per day [95% CI 0·82-1·97] vs 0·40 [0·25-0·62]; difference 0·88 [0·29-1·46]; p=0·0003) and lower urinary THC-COOH concentrations (mean 657·92 ng/mL [95% CI 381·60-1134·30] vs 265·55 [175·60-401·57]; difference 392·37 [17·55-767·18)]; p=0·009). Eight (17%) patients in the PF-04457845 group and four (17%) in the placebo group discontinued during the treatment period. During the 4-week treatment phase, 20 (43%) of 46 participants in the PF-04457845 group and 11 (46%) of 24 participants in the placebo group had an adverse event. There were no serious adverse events.

INTERPRETATION

PF-04457845, a novel FAAH inhibitor, reduced cannabis withdrawal symptoms and cannabis use in men, and might represent an effective and safe approach for the treatment of cannabis use disorder.

FUNDING

United States National Institute of Drug Abuse (NIDA).

Demineralization effects of 10 percent carbamide peroxide

OBJECTIVES

The purpose of this in vitro study was to measure the amount of calcium lost from enamel exposed to a 10% carbamide peroxide solution.

METHODS

Nine teeth (3 incisors, 2 premolars, 4 molars) were sectioned to serve as paired test and control specimens. Each tooth half was coated with wax, leaving a uniform 3 mm x 4 mm window of exposed enamel. Test specimens were placed in culture tubes with 1.00 ml of deionized water and 0.02 ml of 10% carbamide peroxide for 6 h; controls were exposed to water alone. Calcium concentrations in the solutions were measured using a Perkin-Elmer 5100 atomic absorption spectrophotometer.

RESULTS

Teeth exposed to carbamide peroxide lost an average of 1.06 micrograms/mm2 of calcium. This amount of loss was significantly greater than controls (p < 0.001), according to ANOVA. For comparison, teeth were exposed to a cola beverage for 2.5 min, the time equivalent of drinking a 16 oz. beverage. The amount of calcium lost from these teeth was also about 1 microgram/mm2.

CONCLUSIONS

Teeth exposed to 10% carbamide peroxide lost calcium. However, the amount of loss was small, and may not be clinically significant.

Elevated glycogen synthase kinase-3 activity in Fragile X mice: key metabolic regulator with evidence for treatment potential

Significant advances have been made in understanding the underlying defects of and developing potential treatments for Fragile X syndrome (FXS), the most common heritable mental retardation. It has been shown that neuronal metabotropic glutamate receptor 5 (mGluR5)-mediated signaling is affected in FX animal models, with consequent alterations in activity-dependent protein translation and synaptic spine functionality. We demonstrate here that a central metabolic regulatory enzyme, glycogen synthase kinase-3 (GSK3) is present in a form indicating elevated activity in several regions of the FX mouse brain. Furthermore, we show that selective GSK3 inhibitors, as well as lithium, are able to revert mutant phenotypes of the FX mouse. Lithium, in particular, remained effective with chronic administration, although its effects were reversible even when given from birth. The combination of an mGluR5 antagonist and GSK3 inhibitors was not additive. Instead, it was discovered that mGluR5 signaling and GSK3 activation in the FX mouse are coordinately elevated, with inhibition of mGluR5 leading to inhibition of GSK3. These findings raise the possibility that GSK3 is a fundamental and central component of FXS pathology, with a substantial treatment potential.

Discovery of SB-705498: A potent, selective and orally bioavailable TRPV1 antagonist suitable for clinical development

Small molecule antagonists of the vanilloid receptor TRPV1 (also known as VR1) are disclosed. Pyrrolidinyl ureas such as 8 and 15 (SB-705498) emerged as lead compounds following optimisation of the previously described urea SB-452533. Pharmacological studies using electrophysiological and FLIPR-Ca2+-based assays showed that compounds such as 8 and 15 were potent antagonists versus the multiple chemical and physical modes of TRPV1 activation (namely capsaicin, acid and noxious heat). Furthermore, 15 possessed suitable developability properties to enable progression of this compound into in vivo studies and subsequently clinical development.

Diet selection in sheep: the ability of growing lambs to select a diet that meets their crude protein (nitrogen x 6.25) requirements

To test the proposition that sheep are able to select a diet that meets their crude protein (N x 6.25; CP) requirements, feeds L, A, B, C and H with the same energy content (11 MJ metabolizable energy/kg feed) but different CP contents (78, 109, 141, 172 and 235 g CP/kg fresh feed respectively) were formulated. In addition, feed U, which was feed L plus 21.4 g urea/kg (CP content 132 g/kg), was also made. The feeds were offered ad lib. either singly (n 4 per treatment) or as a choice between feed H and another feed (pairs LH, AH, BH, CH and UH; n 9 per feed pair) to individually penned Suffolk x Scottish mule wether lambs, over the live-weight range 25-45 kg. On the single feeds the rates of live-weight gain were 273, 326, 412, 418, 396 and 407 g/day (SE of difference (SED) 34; P < 0.01) and protein (excluding wool) gain were 27, 32, 44, 45, 41 and 39 g/d (SED 4; P < 0.001) for feeds L, A, B, C, H and U respectively. When sheep were given a choice between a feed below (L or A) and a feed above their CP requirements (H; as judged by the single-feeding treatments) the CP concentration selected was not different between the two pairs: 131 (SE 4) v. 133 (SE 4) g CP/kg feed for pairs LH and AH respectively. On the choices BH and CH (a choice between two feeds above requirements) the feed lower in CP was constantly preferred (874 (SE 33) and 910 (SE 33) g feed B and C respectively per kg total feed intake; CP selected was 157 and 178 g CP/kg respectively). However, this was not the case with the UH choice on which sheep consumed only 599 (SE 61) g feed U/kg total feed intake, resulting in a selection of a higher CP in their diet (173 g CP/kg). The live-weight gains of the animals given a choice between two feeds were 416, 387, 415, 410 and 383 g/d (SED 37) and protein gains were 45, 40, 46, 50 and 43 (SE 7) for pairs LH, AH, BH, CH and UH respectively, which were comparable with the best performance achieved on a single feed. The results suggest that sheep were able to select a diet that meets their CP requirements and avoid, at least to a certain extent, excess of protein intake.(ABSTRACT TRUNCATED AT 400 WORDS)

Contribution of orexin in hypercapnic chemoreflex: evidence from genetic and pharmacological disruption and supplementation studies in mice

We have previously shown that hypercapnic chemoreflex in prepro-orexin knockout mice (ORX-KO) is attenuated during wake but not sleep periods. In that study, however, hypercapnic stimulation had been chronically applied for 6 h because of technical difficulty in changing the composition of the inspired gas mixture without distorting the animal's vigilance states. In the present study we examined possible involvement of orexin in acute respiratory chemoreflex during wake periods. Ventilation was recorded together with electroencephalography and electromyography before and after intracerebroventricular administration of orexin or an orexin receptor antagonist, SB-334867. A hypercapnic (5 or 10% CO(2)) or hypoxic (15 or 10% O(2)) gas mixture was introduced into the recording chamber for 5 min. Respiratory parameters were analyzed only for quiet wakefulness. When mice breathed normal room air, orexin-A and orexin-B but not vehicle or SB-334867 increased minute ventilation in both ORX-KO and wild-type (WT) mice. As expected, hypercapnic chemoreflex in vehicle-treated ORX- KO mice (0.22 +/- 0.03 mlxmin(-1)xg(-1)x% CO(2)(-1)) was significantly blunted compared with that in WT mice (0.51 +/- 0.05 mlxmin(-1)xg(-1)x% CO(2)(-1)). Supplementation of orexin-A or -B (3 nmol) partially restored the hypercapnic chemoreflex in ORX-KO mice (0.28 +/- 0.03 mlxmin(-1).g(-1)x% CO(2)(-1) for orexin-A and 0.32 +/- 0.04 mlxmin(-1)xg(-1)x% CO(2)(-1) for orexin-B). In addition, injection of SB-334867 (30 nmol) in WT mice decreased the hypercapnic chemoreflex (0.39 +/- 0.04 mlxmin(-1)xg(-1)x% CO(2)(-1)). On the other hand, hypoxic chemoreflex in vehicle-treated ORX-KO and SB-334867-treated WT mice was not different from that in corresponding controls. Our findings suggest that orexin plays a crucial role in CO(2) sensitivity at least during wake periods in mice.

Etiologic factors in diaper dermatitis: the role of urine

Diaper dermatitis may result after repeated or prolonged contact of skin with urine and feces. A hairless mouse model was used to elucidate the role of urine in this process. The results of this work suggest that an important function of urine in the etiology of diaper dermatitis is to increase the pH of the diaper environment by breaking down urea in the presence of fecal urease. This rise in pH increases the activities of fecal proteases and lipases, which can damage skin. Urine can also increase the permeability of diapered skin to irritants and can directly irritate skin when exposure is prolonged.

Protein stability as a function of denaturant concentration: the thermal stability of barnase in the presence of urea

The conventional procedure for analyzing urea denaturation curves assumes that the free energy of unfolding (delta GU-F) is linearly related to [urea] that is, delta GU-F = delta GH2O(U-F)--m[urea], where m is a constant, specific for each protein, and delta GH2O(U-F) is the free energy of unfolding in water. This relationship can be measured directly, however, over only a small concentration range of approximately +/- 0.8 M urea around the midpoint of the unfolding transition. A nagging discrepancy (1.6 kcal mol-1) between delta GH2O(U-F) at 298 K of barnase extrapolated from such an equation and the equivalent value obtained from thermal unfolding measurements has stimulated a re-evaluation of the equation. Differential scanning calorimetric measurements have been made of the thermal unfolding of barnase in the presence of concentrations of urea between 0 and 4.5 M, the midpoint of the unfolding transition at 298 K, to test the denaturation equation over a wide range of [urea]. Values for delta GU-F at 298 K (delta G298U-F) for each concentration of urea were extrapolated from the calorimetrically measured enthalpies and the denaturational heat capacity change (delta Cdp) measured for that concentration of urea. A plot of delta G298U-F against [urea] deviates systematically from linearity and fits better the equation: delta G298U-F = 10.5 +/- 0.08 - ((2.65 +/- 0.05) x [urea]) + ((0.08 +/- 0.01) x [urea]2) kcal mol-1. The curvature in the plot leads to apparent values of m that increase when measurements are made at lower concentrations of urea. This could account for increases in m at low values of pH or in destabilized mutants since the protein denatures at lower concentrations of urea. It has been shown previously that small curvature in the free energy of unfolding versus [urea] leads to negligible errors in measurements of delta delta GU-F, the change in free energy of unfolding on mutation, providing that the curvature is similar for all mutants. The calorimetrically measured enthalpies of unfolding are decreased in the presence of urea while delta Cdp is increased. Both of these observations are consistent with an overall exothermic interaction between urea and protein with a net increase on unfolding.

Functional inactivation of orexin 1 receptors in CA1 region impairs acquisition, consolidation and retrieval in Morris water maze task

Orexin containing neurons in the lateral hypothalamic area (LHA) produce orexin-A (hypocretin-1) and orexin-B (hypocretin-2) and send their axons to the hippocampus, which predominantly expresses orexin 1 receptors (OX1Rs) showing a higher affinity to orexin-A. Recent studies have shown that central administration of orexin-A has an effect on learning and memory but literature concerning the role of orexinergic system in cognition remains controversial. Therefore, we examined the effect of pre-training, post-training and pre-probe trial intrahippocampal CA1 administration of a selective OX1R the orexin 1 receptor antagonist SB-334867-A (1.5, 3, 6 microg/0.5 microl) on acquisition, consolidation and retrieval in a single-day testing version of Morris water maze (MWM) task. Our results show that, SB-334867-A impaired acquisition, consolidation and retrieval of MWM task as compared with the control group. This drug had no effect on escape latency of a non-spatial visual discrimination task. Therefore, it seems that endogenous orexins, especially orexin-A, play an important role in spatial learning and memory in the rat.