Detection of first gammaherpesvirus sequences in Central African bats

Herpesviruses have been identified in many species; however, relatively few bat herpesvirus are known, considering the enormous diversity of bats. We used consensus PCR to test bats from the Republic of the Congo and found DNA of two different novel bat herpesviruses. One was detected in a Pipistrellus nanulus, the other in a Triaenops persicus bat and both resemble gammaherpesviruses. On the amino acid level, the amplified sequences differ by 55% from each other, and by 27% and 25% from the next closest known viruses. The findings point towards the diversity of herpesviruses in Central African bats.

A Health Services Research Agenda for Bariatric Surgery Within the Veterans Health Administration

In 2016, the Veterans Health Administration (VHA) held a Weight Management State of the Art conference to identify evidence gaps and develop a research agenda for population-based weight management for veterans. Included were behavioral, pharmacologic, and bariatric surgery workgroups. This article summarizes the bariatric surgery workgroup (BSWG) findings and recommendations for future research. The BSWG agreed that there is evidence from randomized trials and large observational studies suggesting that bariatric surgery is superior to medical therapy for short- and intermediate-term remission of type 2 diabetes, long-term weight loss, and long-term survival. Priority evidence gaps include long-term comorbidity remission, mental health, substance abuse, and health care costs. Evidence of the role of endoscopic weight loss options is also lacking. The BSWG also noted the limited evidence regarding optimal timing for bariatric surgery referral, barriers to bariatric surgery itself, and management of high-risk bariatric surgery patients. Clinical trials of pre- and post-surgery interventions may help to optimize patient outcomes. A registry of overweight and obese veterans and a workforce assessment to determine the VHA's capacity to increase bariatric surgery access were recommended. These will help inform policy modifications and focus the research agenda to improve the ability of the VHA to deliver population-based weight management.

Genetic dissection of intraspecific variation in a male-specific sexual trait in Drosophila melanogaster

An open question in evolutionary biology is the relationship between standing variation for a trait and the variation that leads to interspecific divergence. By identifying loci underlying phenotypic variation in intra- and interspecific crosses we can determine the extent to which polymorphism and divergence are controlled by the same genomic regions. Sexual traits provide abundant examples of morphological and behavioral diversity within and among species, and here we leverage variation in the Drosophila sex comb to address this question. The sex comb is an array of modified bristles or ‘teeth' present on the male forelegs of several Drosophilid species. Males use the comb to grasp females during copulation, and ablation experiments have shown that males lacking comb teeth typically fail to mate. We measured tooth number in >700 genotypes derived from a multiparental advanced-intercross population, mapping three moderate-effect loci contributing to trait heritability. Two quantitative trait loci (QTLs) coincide with previously identified intra- and interspecific sex comb QTL, but such overlap can be explained by chance alone, in part because of the broad swathes of the genome implicated by earlier, low-resolution QTL scans. Our mapped QTL regions encompass 70–124 genes, but do not include those genes known to be involved in developmental specification of the comb. Nonetheless, we identified plausible candidates within all QTL intervals, and used RNA interference to validate effects at four loci. Notably, TweedleS expression knockdown substantially reduces tooth number. The genes we highlight are strong candidates to harbor segregating, functional variants contributing to sex comb tooth number.

Outcomes of intravenous tissue plasminogen activator for acute ischaemic stroke in HIV-infected adults

BACKGROUND AND PURPOSE

To our knowledge there are no studies reporting the use and short-term outcomes of intravenous tissue plasminogen activator (IV-TPA) for the treatment of acute ischaemic stroke (AIS) in people living with HIV.

METHODS

The US Nationwide Inpatient Sample (NIS) (2006-2010) was searched for HIV-infected AIS patients treated with IV-TPA.

RESULTS

In the NIS, 2.2% (62/2877) of HIV-infected AIS cases were thrombolyzed with IV-TPA (median age 52 years, range 27-78, 32% female, 22% Caucasian) vs. 2.1% (19 335/937 896) of HIV-uninfected cases (median age 72 years, range 17-102 years, 50% female, 74% Caucasian; P = 0.77). There were more deaths in HIV-infected versus uninfected patients with stroke (220/2877, 7.6% vs. 49 089/937 547, 5.2%, P < 0.001) but no difference in the proportion of deaths amongst IV-TPA-treated patients. The age- and sex-adjusted odds ratio for death following IV-TPA administration in HIV-infected versus uninfected patients was 2.26 (95% CI 1.12, 4.58), but the interaction on mortality between HIV and IV-TPA use was not statistically significant, indicating no difference in risk of in-hospital death by HIV serostatus with IV-TPA use. A higher number of HIV-infected patients remained in hospital versus died or were discharged at both 10 and 30 days (P < 0.01 at 10 and 30 days). No difference in the proportion of intracerebral hemorrhage in the two groups was found (P = 0.362).

CONCLUSIONS

The in-hospital mortality is higher amongst HIV-infected AIS patients than HIV-uninfected patients. However, the risk of death amongst HIV-infected patients treated with IV-TPA is similar to HIV-uninfected groups.

Apparent absolute oral bioavailability in excess of 100% for a vitronectin receptor antagonist (SB-265123) in rat. II. Studies implicating transporter-mediated intestinal secretion

1. Transporters have been increasingly identified as a factor in limiting the oral bioavailability of certain drugs. Previously, the present authors investigated a compound (SB-265123) with an apparent absolute oral bioavailability (Fapp) consistently > 100%, and excluded likely artefactual causes for this observation, as well as standard considerations of non-stationary or non-linear pharmacokinetics. The data led the authors to believe that SB-265123 might be a transporter substrate in the rat, and it was hypothesized that transporter interactions might be responsible for the observed Fapp > 100%. 2. In the present study, a model was proposed incorporating rapid and complete absorption and elimination by a saturable intestinal secretory pathway. Intestinal secretion was demonstrated for SB-265123 using a rat single-pass intestinal perfusion technique. In addition, in a study employing both independent and simultaneous intravenous and oral administration of SB-265123, exposure to SB-265123 was greater than additive on joint intravenous and oral administration, lending further support to the hypothesis of a saturable transporter. Furthermore, in a study with co-administration of GF120918A, a transporter inhibitor, the observed Fapp for SB-265123 was only 84 +/- 17%, providing additional evidence for transporter involvement in the >100% Fapp phenomenon. 3. Experience with SB-265123 illustrates a counterintuitive impact of transporters on oral bioavailability and highlights the importance of considering transporter interactions in the systemic disposition of xenobiotics, even those not demonstrating low oral bioavailability.

An indigenous plant food used by lactating mothers in west Africa: the nutrient composition of the leaves of Kigelia africana in Ghana

Although the leaves of Kigelia africana are used to make a palm-nut soup which is consumed mainly by lactating women in many parts of sub-Saharan Africa, little is known about the nutrient qualities of this underutilized and underappreciated plant food. Leaves of Kigelia africana, called "sausage tree" in English and "nufuten" in the Twi language of Ghana, were collected in Kumasi and analyzed for their content of nutritionally important fatty acids, amino acids, minerals, and trace elements. The dried leaves contained 1.62% fatty acids, of which α-linolenic acid and linolenic acid accounted for 44% and 20%, respectively, of the total. Protein accounted for 12.6% of the dry weight and, except for lysine, its overall essential amino acid profile compared favorably to a World Health Organization protein standard for school children. Kigelia leaf contained considerable amounts of many essential elements, including calcium (7,620 μg/g), iron (161 μg/g), magnesium (2,310 μg/g), manganese (14.6 μg/g), zinc (39.9 μg/g), and chromium (0.83 μg/g); selenium, however, was not detected. These data indicate that Kigelia africana leaf compares favorably with many other commonly-consumed green leafy vegetables such as spinach and provides a rational basis for promoting the conservation and propagation of the plant and encouraging its wider use in the diets of populations in sub-Saharan Africa.

Re-thinking wastewater landscapes: combining innovative strategies to address tomorrow's urban wastewater treatment challenges

Most major cities worldwide face urban water management challenges relating to drinking supply, stormwater and wastewater treatment, and ecological preservation. In light of climate change and finite natural resources, addressing these challenges in sustainable ways will require innovative solutions arising from interdisciplinary collaboration. This article summarizes five major urban water management strategies that bridge the fields of engineering, ecology, landscape architecture, and urban planning. A conceptual implementation of these strategies is demonstrated through a design for a small constructed wetland treatment system in San Francisco, California. The proposed decentralized system described in this article consists of a detention basin, vegetated and open free water surface wetlands, and ultraviolet disinfection. In wet weather, the system would detain and treat combined sewer discharges (CSD), and in dry weather it would treat residential greywater for toilet flushing and irrigation in a nearby neighborhood. It is designed to adapt over time to changing climatic conditions and treatment demands. Importantly, this proposal demonstrates how constructed wetland engineers can incorporate multiple benefits into their systems, offering a vision of how wastewater infrastructure can be an attractive community, educational, recreational, and habitat amenity through the integration of engineering, ecology, and landscape design.

Apparent absolute oral bioavailability in excess of 100% for a vitronectin receptor antagonist (SB-265123) in rat. I. Investigation of potential experimental and mechanistic explanations

1. SB-265123 is a novel alphavbeta3 (the vitronectin receptor) antagonist. Previous rat studies with it revealed an apparent absolute oral bioavailability (Fapp) of greater than 100%. The present studies were conducted to investigate the potential causes for this observation. 2. Of 49 SB-265123 analogues evaluated in rat using an identical experimental design, Fapp > 100% was observed for 22 of them, suggesting that the observed Fapp >100% with SB-265123 was not anomalous. All 22 compounds had clearances < 15 ml min(-1) kg(-1). However, Fapp>100% were not recorded for all low-clearance analogues. 3. Using SB-265123 as a model to investigate potential artefacts, it was demonstrated that using a chiral assay did not decrease Fapp. Additionally, qualitative sample analysis demonstrated that no metabolites were present in the plasma that could interfere with the liquid chromatography coupled with tandem mass spectrometry detection assay. The high Fapp was also dose-order-, delivery system- and vehicle-independent, and was not affected by the feeding status of the animals. Furthermore, a linearity experiment and an absorption study indicated that oral administration of SB-265123 does not result in hepatic portal vein concentrations that exceed the pharmacokinetic linearity of SB-265123. 4. These observations suggest that the observed Fapp > 100% for SB-265123 is not due to an experimental artefact or an obvious pharmacokinetic non-linearity. The mechanism(s) for this phenomenon is explored further in the second part of the present paper.

Structure-function relations of the thyrotropin receptor

The thyrotropin (thyroid-stimulating hormone or TSH) receptor is an amphiphilic membrane component with a relative molecular mass of about 200,000 as judged by gel filtration and an isoelectric point close to pH 5. Analyses with chemical, enzymic and affinity probes indicate that the receptor is a glycoprotein containing a disulphide bridge and that the integrity of the disulphide bond is essential for maintaining the structure of the TSH-binding site. Serum from patients with Graves' disease contains antibodies which inhibit the binding of TSH to its receptor and there is considerable evidence that this effect is due to a direct interaction between the antibodies and the receptor. The antibody-receptor interaction is probably responsible for the TSH agonist properties of Graves' serum and, similarly, the TSH antagonist properties of the sera from a small number of patients can be explained on the basis of antibody-receptor binding. Although TSH and IgG from Graves' disease patients appear to bind to the same receptor, the relationship between the sites for the two substances is not clearly understood. However, Fab fragments of Graves' IgG are as effective as intact IgG in competing with TSH for the receptor and gel filtration and immunoprecipitation studies indicate that the binding of hormone and antibody to the receptor is mutually exclusive. Current evidence suggests therefore that the binding sites for TSH and TSH receptor antibodies are very closely related and may well be identical.

A mechanism of injury to the forefoot in car crashes

OBJECTIVE

The purpose of this study was to determine a mechanism of injury of the forefoot due to impact loads and accelerations as noted in some frontal offset car crashes.

METHODS

The impact tests conducted simulated knee-leg-foot entrapment, floor pan intrusions, whole-body deceleration, muscle tension, and foot/pedal interaction. Specimens were impacted at speeds of up to 16 m/s. To verify this injury mechanism research was conducted in an effort to produce Lisfranc type injuries and metatarsal fractures. A total of 54 lower legs of post-mortem human subjects were tested. Two possible mechanisms of injury were investigated. For the first mechanism the driver was assumed to be braking hard with the foot on the brake pedal and at 0 deg plantar flexion (Plantar Nominal Configuration) and the brake pedal was in contact with the foot behind the ball of the foot. The second mechanism was studied by having the ball of the foot either on the brake pedal or on the floorboard with the foot plantar-flexed 35 to 50 deg (Plantar Flexed Configuration).

RESULTS

The Plantar Nominal injury mechanism yielded few injuries of the type the study set out to produce. Out of 13 specimens tested at speeds of 16 m/s, three had injuries of the metatarsal (MT) and tarsometatarsal joints. The Plantar Flexed Configuration injury mechanism yielded 65% injuries at high (12.5-16 m/s) and moderate (6-12 m/s) speeds.

CONCLUSION

It is concluded that Lisfranc type foot injuries are the result of impacting the forefoot in the Plantar Flexed Configuration. The injuries were consistent with those reported by physicians treating accident victims and were verified by an orthopedic surgeon during post impact x-ray and autopsy. They included Lisfranc fractures, ligamentous disruptions, and metatarsal fractures.

CDtool-an integrated software package for circular dichroism spectroscopic data processing, analysis, and archiving

CDtool is a software package written to facilitate circular dichroism (CD) spectroscopic studies on both conventional lab-based instruments and synchrotron beamlines. It takes format-independent input data from any type of CD instrument, enables a wide range of standard and advanced processing methods, and, in a single user-friendly graphics-based package, takes raw data through the entire processing procedure and, importantly, uses data-mining techniques to retain in the final output all the information associated with the processing. It permits the facile comparison of data obtained from different instruments without the need for reformatting and displays it in graphical formats suitable for publication. It also includes the ability to automatically archive the processed data. This latter feature may be especially useful in light of recent funding institution directives with regard to data sharing and archiving and requirements for "good practice" and "traceability" within the pharmaceutical industry. In addition, CDtool includes a means of interfacing with protein data bank coordinate files and calculating secondary structures from them using alternate definitions and algorithms. This feature, along with a function that permits the facile production of new reference databases, enables the creation of specialized databases for secondary structural analyses of specific types of proteins. Thus the CDtool software not only enables rapid data processing and analyses but also includes many enhanced features not available in other CD data processing/analysis packages.

Accuracy, efficiency and robustness of four algorithms allowing full sibship reconstruction from DNA marker data

In the problem of reconstructing full sib pedigrees from DNA marker data, three existing algorithms and one new algorithm are compared in terms of accuracy, efficiency and robustness using real and simulated data sets. An algorithm based on the exclusion principle and another based on a maximization of the Simpson index were very accurate at reconstructing data sets comprising a few large families but had problems with data sets with limited family structure, while a Markov Chain Monte Carlo (MCMC) algorithm based on the maximization of a partition score had the opposite behaviour. An MCMC algorithm based on maximizing the full joint likelihood performed best in small data sets comprising several medium-sized families but did not work well under most other conditions. It appears that the likelihood surface may be rough and presents challenges for the MCMC algorithm to find the global maximum. This likelihood algorithm also exhibited problems in reconstructing large family groups, due possibly to limits in computational precision. The accuracy of each algorithm improved with an increasing amount of information in the data set, and was very high with eight loci with eight alleles each. All four algorithms were quite robust to deviation from an idealized uniform allelic distribution, to departures from idealized Mendelian inheritance in simulated data sets and to the presence of null alleles. In contrast, none of the algorithms were very robust to the probable presence of error/mutation in the data. Depending upon the type of mutation or errors and the algorithm used, between 70 and 98% of the affected individuals were classified improperly on average.

Thyroid autoantibodies

The characteristics of thyroid autoantibodies are reviewed and new assays for the autoantibodies described, in particular point of care (POC) tests for thyroid peroxidase (TPO) autoantibodies and for thyroglobulin (Tg) autoantibodies. These POC tests depend on the ability of the autoantibodies to inhibit gold labelled human monoclonal antibodies binding to TPO or to Tg. The POC tests show similar sensitivity and specificity to conventional ELISA for the autoantibodies. A new ELISA to measure autoantibodies to the TSH receptor (TRAb) is described, is based on TSH receptor coated onto plate wells by way of a monoclonal antibody. Comparison of porcine and human TSH receptors indicates that there is no advantage in using human TSHR in assay systems based on competition between TRAb and bovine or porcine TSH for immobilised TSHR. In terms of the origins of Graves' disease, it is speculated that this most common overt autoimmune disease in man might have occurred first when Homo sapiens sapiens migrated rapidly out of Africa about 100,000 years ago.

A potent small molecule, nonpeptide inhibitor of cathepsin K (SB 331750) prevents bone matrix resorption in the ovariectomized rat

Inhibition of the cyteine proteinase, cathepsin K (E.C. 3.4.22.38) has been postulated as a means to control osteoclast-mediated bone resorption. The preferred animal models for evaluation of antiresorptive activity are in the rat. However, the development of compounds that inhibit rat cathepsin K has proven difficult because the human and rat enzymes differ in key residues in the active site. In this study, a potent, nonpeptide inhibitor of rat cathepsin K (K(i) = 4.7 nmol/L), 5-(2-morpholin-4-yl-ethoxy)-benzofuran-2-carboxylic acid ((S)-3-methyl-1-(3-oxo-1-[2-(3-pyridin-2-yl-phenyl)-ethenoyl]-azepan-4-ylcarbanoyl)-butyl)-amide (SB 331750), is described, which is efficacious in rat models of bone resorption. SB 331750 potently inhibited human cathepsin K activity in vitro (K(i) = 0.0048 nmol/L) and was selective for human cathepsin K vs. cathepsins B (K(i) = 100 nmol/L), L (0.48 nmol/L), or S (K(i) = 14.3 nmol/L). In an in situ enzyme assay, SB 331750 inhibited osteoclast-associated cathepsin activity in tissue sections containing human osteoclasts (IC(50) approximately 60 nmol/L) and this translated into potent inhibition of human osteoclast-mediated bone resorption in vitro (IC(50) approximately 30 nmol/L). In vitro, SB 331750 partially, but dose-dependently, prevented the parathyroid hormone-induced hypercalcemia in an acute rat model of bone resorption. To evaluate the ability of SB 331750 to inhibit bone matrix degradation in vivo, it was administered for 4 weeks at 3, 10, or 30 mg/kg, intraperitoneally (i.p.), u.i.d. in the ovariectomized (ovx) rat. Both 10 and 30 mg/kg doses of compound prevented the ovx-induced elevation in urinary deoxypyridinoline and prevented the ovx-induced increase in percent eroded perimeter. Histological evaluation of the bones from compound-treated animals indicated that SB 331750 retarded bone matrix degradation in vivo at all three doses. The inhibition of bone resorption at the 10 and 30 mg/kg doses resulted in prevention of the ovx-induced reduction in percent trabecular area, trabecular number, and increase in trabecular spacing. These effects on bone resorption were also reflected in inhibition of the ovx-induced loss in trabecular bone volume as assessed using microcomputerized tomography (microCT; approximately 60% at 30 mg/kg). Together, these data indicate that the cathepsin K inhibitor, SB 331750, prevented bone resorption in vivo and this inhibition resulted in prevention of ovariectomy-induced loss in trabecular structure.

SB-242235, a selective inhibitor of p38 mitogen-activated protein kinase. I: preclinical pharmacokinetics

1. SB-242235 (1-(4-piperidinyl)-4-(4-fluorophenyl)-5-(2-methoxy-4-pyrimidinyl) imidazole) is a potent and selective p38 MAP kinase inhibitor that may be an effective therapy for cytokine-mediated diseases such as autoimmune or inflammatory diseases. The present studies were conducted to evaluate the pharmacokinetics of SB-242235 in several preclinical species, including rat, dog and monkey. 2. SB-242235 demonstrates generally favourable pharmacokinetic properties in all species examined. Systemic plasma clearance was high in rat, but in the non-rodent species SB-242235 demonstrated low to moderate clearance with plasma half-lives > 4h. Oral bioavailability in each preclinical species was high. In rat and monkey, SB-242235 demonstrated non-linear elimination kinetics that manifested as a decrease in clearance with increasing dose and apparent oral bioavailability > 100% at high oral doses. Furthermore, SB-242235 displayed concentration-dependent plasma protein binding over a concentration range of 1000-10,000 ng ml(-1). 3. In conclusion, SB-242235 demonstrates high oral bioavailability across the major preclinical species, and may thus be a useful tool compound for investigation of the role of p38 inhibition in various disease states. However, the observations of non-linear protein binding and disposition also suggest the need for caution in the design of and data interpretation from such studies.

SB-242235, a selective inhibitor of p38 mitogen-activated protein kinase. II: in vitro and in vivo metabolism studies and pharmacokinetic extrapolation to man

1. Inhibition of p38 MAP kinase has been investigated extensively as a potential therapy for cytokine-mediated diseases such as autoimmune and inflammatory diseases. SB-242235 (1-(4-piperidinyl)-4-(4-fluorophenyl)-5-(2-methoxy-4-pyrimidinyl) imidazole) is a potent and selective p38 MAP kinase inhibitor; the preclinical pharmacokinetics of SB-242235 have been described previously. The present studies were conducted to describe the in vitro metabolic rates and routes of SB-242235 metabolism, to characterize its in vivo preclinical metabolism, and to use these data to aid in the prediction of the pharmacokinetic behaviour of SB-242235 in man. 2. SB-242235 was metabolically stable in rat, dog, monkey and human hepatic microsomes, isolated hepatocytes and liver slices in vitro. The in vivo preclinical metabolism studies were consistent with the in vitro findings; SB-242235 was minimally metabolized, and was primarily excreted unchanged in the urine (45 and 67% of the administered dose in the rat and monkey, respectively). 3. Allometric scaling using various correction factors predicted that SB-242235 would have low clearance in man with a predicted half-life ranging from 11.5 to 18.7h. This prediction was consistent with the observed mean half-life of 16.4h in the first-in-man study for SB-242235. An allometric scaling method with a correction for interspecies differences in glomerular filtration rate provided the most accurate prediction of the pharmacokinetic behaviour of SB-242235 in humans, although the clinical data also highlight potential difficulties in conducting prospective allometry.

Caffeine promotes an ethanol-induced conditioned taste aversion: a dose-dependent interaction

The present study examined whether caffeine administered within a dose range previously shown to promote ethanol drinking would also alter an ethanol-induced conditioned taste aversion (CTA). The results revealed a dose-dependent interaction between caffeine and ethanol where caffeine (2.5 and 10 mg/kg) promoted an ethanol-induced CTA at a low ethanol dose (1.0 g/kg) but had no effect in blocking CTA at the higher ethanol dose (1.5 g/kg). These results were found to be unrelated to an alteration in ethanol metabolism, as caffeine had no effect in altering blood ethanol levels at the doses tested. In agreement with the reward comparison hypothesis, the present results suggest that rather than attenuate ethanol's "aversive" effects, caffeine may have promoted an ethanol-induced CTA by increasing the reinforcing efficacy of ethanol.

Caffeine, nicotine and mecamylamine share stimulus properties in the preexposure conditioned taste aversion procedure

RATIONALE

The present study examined whether nicotine and caffeine, two of the most widely used psychoactive drugs, share stimulus properties in the preexposure conditioned taste aversion (CTA) procedure.

OBJECTIVES

To determine whether nicotine would attenuate the formation of a caffeine-induced CTA and further assess whether pretreatment with mecamylamine, a nicotinic receptor antagonist, would reverse nicotine's attenuating effect of a caffeine-induced CTA.

METHODS

Male Wistar rats were preexposed with one of three doses of nicotine (0.6, 1.2 and 2.0 mg/kg, s.c.) for three consecutive days, then 24 h following the final preexposure injection were conditioned with caffeine (20 mg/kg and 30 mg/kg, i.p.) in a standard two-bottle test. There were four conditioning trials and four drug-free test days. In a follow-up study, rats were pretreated with mecamylamine (2 mg/kg, i.p.) prior to preexposure injections with nicotine (0.6 mg/kg, i.p.), then subsequently conditioned with caffeine (20 mg/kg, i.p.) as described above.

RESULTS

The lowest nicotine dose (0.6 mg/kg) attenuated the caffeine induced CTAs (20 mg/kg and 30 mg/kg) but the higher nicotine doses showed no such attenuating effect. In addition, mecamylamine reversed the nicotine-induced attenuation of the caffeine-induced CTA and also directly attenuated it.

CONCLUSIONS

These results suggested that caffeine, nicotine and mecamylamine share overlapping stimulus properties and that the nature of this relationship may involve action at the nicotinic-cholinergic receptor.

X-ray crystal structure of a monoclonal antibody that binds to a major autoantigenic epitope on thyroid peroxidase

Thyroid peroxidase (TPO) catalyzes the production of thyroid hormones and is a major autoantigen in autoimmune thyroid disease (AITD). It is believed that the majority of TPO autoantibodies bind to an immunodominant region consisting of two overlapping domains. Precise location of these domains would help our understanding of the interaction between TPO and TPO autoantibodies. 4F5 is a mouse monoclonal antibody (IgG1, kappa) that reacts with high affinity (2.6 x 10(10) mol/L(-1)) with one of the major autoantigenic regions on TPO. Heavy chain genes of 4F5 were from the VH1 germline gene family, germline genes for the D region could not be assigned and the J region was from the JH2 germline. Light chain genes were from Vkappa4/5 and Jkappa2, germline gene families. The Fab fragment of 4F5 was prepared by papain digestion, purified, crystallized, and the structure solved to 1.9 A using molecular replacement. The refined structure had an R factor of 19.5% and a free R factor of 23.9%. Deduced amino acid sequence and amino acid sequence obtained from diffraction analysis were compared and used to finalize the 4F5 Fab model. Structural analysis indicated that the structure of 4F5 is that of a standard Fab and its combining site is flat and is rich in tyrosine residues. Comparison of the structure of 4F5 with that of a TPO autoantibody Fab, TR1.9 suggests that the two antibodies are unlikely to recognise the same structures on TPO.

Preclinical pharmacokinetics of SB-203580, a potent inhibitor of p38 mitogen-activated protein kinase

1. SB-203580 (4-(4-fluorophenyl)-2-(4-methylsulphinylphenyl)-5-(4-pyridyl)imidazole) is a potent, selective inhibitor of p38 MAP kinase used extensively as a tool inhibitor in various pharmacological and toxicological models. This study was designed to evaluate the pharmacokinetics of SB-203580 in several preclinical species, both to assist with the interpretation of existing studies and to aid in the design of future studies with this inhibitor. 2. In vitro, SB-203580 was stable in mouse, rat, dog, monkey and human plasma over 24 h. However, species differences in plasma protein binding were observed; SB-203580 was 96-97% bound in human plasma and 78-92% bound in other species. These data suggest that protein binding may influence the results of in vitro studies using SB-203580, particularly when comparing results from different in vitro systems that incorporate plasma components. In vivo, SB-203580) demonstrated moderate to high clearance in all species tested, with non-linear elimination observed in the rat at plasma concentrations > 1,000 ngml(-1). Although good solution bioavailability was observed in non-rodents (78% in dog, 32% in monkey), lower and more variable bioavailability was observed in the rat and mouse (3 -48%). 3. These interspecies differences in bioavailability, and the non-linear pharmacokinetics observed in rat, highlight the importance of monitoring SB-203580 systemic exposure in parallel witb the pharmacological endpoint during in vivo pharmacology

Immobilized IL-8 triggers progressive activation of neutrophils rolling in vitro on P-selectin and intercellular adhesion molecule-1

The chemokine IL-8 is found on the luminal side of vascular endothelial cells, where it is postulated to be immobilized during inflammation. In this study, we observed that immobilized IL-8 can stimulate neutrophils to firmly adhere to a substrate containing ICAM-1 in a static adhesion assay. Soluble IL-8 was then perfused over neutrophils rolling on P-selectin (P-sel) and ICAM-1, confirming that IL-8 in solution can quickly cause rolling neutrophils to arrest. To mimic a blood vessel wall with IL-8 expressed on the luminal surface of endothelial cells, IL-8 was immobilized along with P-sel and ICAM-1 at defined site densities to a surface. Neutrophils rolled an average of 200 microm on surfaces of P-sel, ICAM-1, and IL-8 before firmly adhering through ICAM-1-beta(2) integrin interactions at 2 dynes/cm(2) wall shear stress. Increasing the density of IL-8 from 60 to 350 sites/microm(2) on the surface decreased by 50% the average distance and time the neutrophils rolled before becoming firmly adherent. Temporal dynamics of ICAM-1-beta(2) integrin interactions of rolling neutrophils following IL-8 exposure suggest the existence of two classes of beta(2) integrin-ICAM-1 interactions, a low avidity interaction with a 65% increase in pause times as compared with P-sel-P-sel glycoprotein ligand-1 interactions, and a high avidity interaction with pause times 400% greater than the selectin interactions. Based on the proportionality between IL-8 site density and time to arrest, it appears that neutrophils may need to sample a critical number of IL-8 molecules presented by the vessel wall before forming a sufficient number of high avidity beta(2) integrin bonds for firm adhesion.

Potent and selective inhibition of human cathepsin K leads to inhibition of bone resorption in vivo in a nonhuman primate

Cathepsin K is a cysteine protease that plays an essential role in osteoclast-mediated degradation of the organic matrix of bone. Knockout of the enzyme in mice, as well as lack of functional enzyme in the human condition pycnodysostosis, results in osteopetrosis. These results suggests that inhibition of the human enzyme may provide protection from bone loss in states of elevated bone turnover, such as postmenopausal osteoporosis. To test this theory, we have produced a small molecule inhibitor of human cathepsin K, SB-357114, that potently and selectively inhibits this enzyme (Ki = 0.16 nM). This compound potently inhibited cathepsin activity in situ, in human osteoclasts (inhibitor concentration [IC]50 = 70 nM) as well as bone resorption mediated by human osteoclasts in vitro (IC50 = 29 nM). Using SB-357114, we evaluated the effect of inhibition of cathepsin K on bone resorption in vivo using a nonhuman primate model of postmenopausal bone loss in which the active form of cathepsin K is identical to the human orthologue. A gonadotropin-releasing hormone agonist (GnRHa) was used to render cynomolgus monkeys estrogen deficient, which led to an increase in bone turnover. Treatment with SB-357114 (12 mg/kg subcutaneously) resulted in a significant reduction in serum markers of bone resorption relative to untreated controls. The effect was observed 1.5 h after the first dose and was maintained for 24 h. After 5 days of dosing, the reductions in N-terminal telopeptides (NTx) and C-terminal telopeptides (CTx) of type I collagen were 61% and 67%, respectively. A decrease in serum osteocalcin of 22% was also observed. These data show that inhibition of cathepsin K results in a significant reduction of bone resorption in vivo and provide further evidence that this may be a viable approach to the treatment of postmenopausal osteoporosis.

A high-sensitivity enzyme-linked immunosorbent assay for serum thyroglobulin

A sensitive enzyme-linked immunosorbent assay (ELISA) for measuring serum thyroglobulin (Tg) is described. The assay has a functional sensitivity of 0.03 ng/mL and values obtained in sera from patients with treated differentiated thyroid cancer (DTC; n = 24, 17 of whom showed some evidence of recurrence) and from healthy blood donors (n = 48) were in agreement with those obtained by Tg immunoradiometric assay (IRMA) (functional sensitivity = 0.6 ng/ml) (r = 0.99 and 0.98 for the two groups, respectively). The Tg levels measured by ELISA in 47 of the healthy blood donor sera ranged from 2.3 to 139 ng/ml with 1 serum giving a value of 0.03 ng/mL. The mean +/- standard deviation (SD) Tg concentration for the healthy blood donors was 20.3+/-23 ng/mL. Studies with a recovery test suggest that Tg measurements by ELISA were not always reliable when Tg autoantibodies were present. Analysis of samples from 167 patients treated successfully for DTC (papillary carcinoma, 94; follicular carcinoma, 73) showed that 139 were negative for Tg autoantibodies and of these 106 (76%) had Tg levels measurable by ELISA (0.03 ng/mL or greater). In contrast, only 7 (5%) of these 139 sera had Tg levels measurable by IRMA (0.6 ng/mL or greater). It is possible that this ability to measure Tg simply and easily in most treated DTC patients will have significant advantages for patient care. In particular, the Tg level after initial ablative treatment will usually be measurable rather than undetectable. Furthermore, any increases in serum Tg levels which may herald relapse will be detectable earlier.

SB-239063, a potent and selective inhibitor of p38 map kinase: preclinical pharmacokinetics and species-specific reversible isomerization

PURPOSE

A series of studies was conducted to evaluate the preclinical pharmacokinetics of SB-239063 (trans-1-(4-hydroxycyclohexyl)-4-(4-fluorophenyl)-5-[(2-methoxy)pyrimidin-4-yl] imidazole), a potent and selective p38 MAP kinase inhibitor.

METHODS

SB-239063 was administered both i.v. and p.o. in the rat, dog, cynomolgus monkey, and rhesus monkey, with standard pharmacokinetic parameters generated from the concentration vs. time data.

RESULTS

Initial rat studies suggested possible nonlinear disposition, however, assay refinement revealed an in vivo trans-cis isomerization of SB-239063 to a metabolite with nearly identical chromatographic and mass spectral properties. SB-239063 exhibited low to moderate clearance and good bioavailability in the rat and dog, but poor bioavailability in the cynomolgus monkey. Substantial in vivo trans-cis isomerization occurred in the rat and cynomolgus monkey, but occurred to a far lesser extent in the dog. The isomerization reaction was reversible, with a recycled fraction of 0.20 and 0.0003 in the rat and cynomolgus monkey, respectively. In the rhesus monkey, bioavailability was also poor. but no in vivo isomerization was observed. Conclusions. These studies demonstrate the necessity of exercising vigilance in conducting high-throughput analytical method development, and the importance of using a variety of preclinical species when evaluating the disposition of new drug candidates.

Accurate partition of individuals into full-sib families from genetic data without parental information

Two Markov chain Monte Carlo algorithms are proposed that allow the partitioning of individuals into full-sib groups using single-locus genetic marker data when no parental information is available. These algorithms present a method of moving through the sibship configuration space and locating the configuration that maximizes an overall score on the basis of pairwise likelihood ratios of being full-sib or unrelated or maximizes the full joint likelihood of the proposed family structure. Using these methods, up to 757 out of 759 Atlantic salmon were correctly classified into 12 full-sib families of unequal size using four microsatellite markers. Large-scale simulations were performed to assess the sensitivity of the procedures to the number of loci and number of alleles per locus, the allelic distribution type, the distribution of families, and the independent knowledge of population allelic frequencies. The number of loci and the number of alleles per locus had the most impact on accuracy. Very good accuracy can be obtained with as few as four loci when they have at least eight alleles. Accuracy decreases when using allelic frequencies estimated in small target samples with skewed family distributions with the pairwise likelihood approach. We present an iterative approach that partly corrects that problem. The full likelihood approach is less sensitive to the precision of allelic frequencies estimates but did not perform as well with the large data set or when little information was available (e.g., four loci with four alleles).

The effects of heparin, protamine, and heparin/protamine reversal on platelet function under conditions of arterial shear stress

Platelet dysfunction contributes to blood loss after cardiopulmonary bypass. This study examined the antiplatelet effects of heparin, protamine, and varying heparin/protamine ratios in an in vitro physiologic model and further elucidated the mechanism of the antiplatelet and anticoagulant effects of protamine. We used the Clot Signature Analyzer (CSA(TM)), a system that analyzes coagulation in flowing whole blood, to test two aspects of platelet function, with different concentrations of heparin and protamine, under conditions simulating arterial flow: collagen-induced thrombus formation (CITF) under moderate shear and high shear platelet activation, platelet hemostasis time (PHT). In addition, platelet aggregometry, celite activated clotting time (Hepcon(TM) ACT), prothrombin time (PT), and partial thromboplastin time (PTT) were measured. Both PHT and the CITF were prolonged by heparin at 20 microg/mL, protamine at 20 and 40 microg/mL, and heparin/protamine ratios of 1:1 and 1:2, but not at 1:1.5. The Hepcon ACT was prolonged by heparin 20 microg/mL and protamine alone at 20 and 40 microg/mL, was normal at a ratio of 1:1, and was prolonged at 1:1.5 and 1:2. Protamine 80 microg/mL prolonged the PT and PTT. Dependency on thrombin, protein kinase C activation, and nonspecific charge effects were examined. The direct thrombin inhibitor D-phenylalanyl-L-prolyl-L-arginyl-chloromethyl ketone prolonged the PHT and ACT, but not the CITF, whereas the polycationic molecules polyarginine and polylysine prolonged the CITF, but not the PHT. The effect of protamine on the PTT, but not PT, could be shortened by the addition of excess phospholipid. Therefore, heparin inhibits both high shear collagen-independent and moderate shear collagen-dependent platelet activation; however, the latter is not mediated by its antithrombin activity. Protamine's antithrombin effect may explain its inhibition of platelet activation at high shear stress. Protamine's nonspecific charge effects are more important for inhibiting moderate shear collagen-induced platelet activation.

IMPLICATIONS

This study suggests that protamine reversal of heparin's antiplatelet effect occurs within a narrow window because of the direct antiplatelet effects of protamine. Antithrombin effects may explain the inhibition of shear activation of platelets by both heparin and protamine. Nonspecific charge effects of protamine may explain the inhibition of collagen platelet activation in the presence of medium shear.

Inhibition of p38 mitogen-activated protein kinase provides neuroprotection in cerebral focal ischemia

Mitogen-activated protein kinases (MAPKs) are involved in many cellular processes. The stress-activated MAPK, p38, has been linked to inflammatory cytokine production and cell death following cellular stress. Here, we demonstrate focal ischemic stroke-induced p38 enzyme activation (i.e., phosphorylation) in the brain. The second generation p38 MAPK inhibitor SB 239063 was identified to exhibit increased kinase selectivity and improved cellular and in vivo activity profiles, and thus was selected for evaluation in two rat models of permanent focal ischemic stroke. SB 239063 was administered orally pre- and post-stroke and intravenously post-stroke. Plasma concentration levels were achieved in excess of those that effectively inhibit p38 activity. In both moderate and severe stroke, SB 239063 reduced infarct size by 28-41%, and neurological deficits by 25-35%. In addition, neuroprotective plasma concentrations of SB 239063 that reduced p38 activity following stroke also reduced the stroke-induced expression of IL-1beta and TNFalpha (i.e., cytokines known to contribute to stroke-induced brain injury). SB 239063 also provided direct protection of cultured brain tissue to in vitro ischemia. This robust SB 239063-induced neuroprotection emphasizes a significant opportunity for targeting MAPK pathways in ischemic stroke injury, and also suggests that p38 inhibition be evaluated for protective effects in other experimental models of nervous system injury and neurodegeneration.

SB 239063, a second-generation p38 mitogen-activated protein kinase inhibitor, reduces brain injury and neurological deficits in cerebral focal ischemia

The stress-activated mitogen-activated protein kinase (MAPK) p38 has been linked to the production of inflammatory cytokines/mediators/inflammation and death/apoptosis following cell stress. In these studies, a second-generation p38 MAPK inhibitor, SB 239063 (IC(50) = 44 nM), was found to exhibit improved kinase selectivity and increased cellular (3-fold) and in vivo (3- to 10-fold) activity over first-generation inhibitors. Oral SB 239063 inhibited lipopolysaccharide-induced plasma tumor necrosis factor production (IC(50) = 2.6 mg/kg) and reduced adjuvant-induced arthritis (51% at 10 mg/kg) in rats. SB 239063 reduced infarct volume (48%) and neurological deficits (42%) when administered orally (15 mg/kg, b.i.d.) before moderate stroke. Intravenous SB 239063 exhibited a clearance of 34 ml/min/kg, a volume of distribution of 3 l/kg, and a plasma half-life of 75 min. An i.v. dosing regimen that provided effective plasma concentrations of 0.38, 0.75, or 1.5 microg/ml (i.e., begun 15 min poststroke and continuing over the initial 6-h p38 activation period) was used. Significant and dose-proportional brain penetration of SB 239063 was demonstrated during these infusion periods. In both moderate and severe stroke, intravenous SB 239063 produced a maximum reduction of infarct size by 41 and 27% and neurological deficits by 35 and 33%, respectively. No effects of the drug were observed on cerebral perfusion, hemodynamics, or body temperature. Direct neuroprotective effects from oxygen and glucose deprivation were also demonstrated in organotypic cultures of rat brain tissue. This robust in vitro and in vivo SB 239063-induced neuroprotection emphasizes the potential role of MAPK pathways in ischemic stroke and also suggests that p38 inhibition warrants further study, including protection in other models of nervous system injury and neurodegeneration.

Differences in locomotor response to an inescapable novel environment predict sensitivity to aversive effects of amphetamine

Differences in locomotor response to an inescapable novel environment have previously been shown to predict sensitivity to amphetamine reward, where high responders (HR), compared to low responders (LR), showed greater initial sensitivity to amphetamine self-administration. The present experiments sought to extend these findings and assessed the relationship between locomotor response to an inescapable novel environment and conditioned taste aversion (CTA) with amphetamine and lithium chloride (LiCl). Male Sprague-Dawley rats were tested for their locomotor response to an inescapable novel environment and divided into high (HR) or low (LR) responders, based on whether their locomotor scores were above or below the median activity level of the subject sample. After several days, the animals were tested in a CTA procedure and conditioned with either amphetamine or lithium chloride. Compared to HR rats, LR rats showed greater sensitivity to amphetamine CTA at the doses tested. In contrast, the results with LiCl showed no relationship between locomotor response to an inescapable novel environment and CTA. Taken together, the present results suggest that LR, compared to HR, rats show less sensitivity to the rewarding effects of amphetamine because they are more sensitive to aversive effects of amphetamine, as reflected in CTA. In contrast, HR rats display less sensitivity to aversive effects of amphetamine, which may explain their greater propensity to self-administer amphetamine.

Antagonism of the osteoclast vitronectin receptor with an orally active nonpeptide inhibitor prevents cancellous bone loss in the ovariectomized rat

An orally active, nonpeptide Arg-Gly-Asp (RGD) mimetic alpha(v)beta3 antagonist, (S)-3-Oxo-8-[2-[6-(methylamino)-pyridin-2-yl]-1-ethoxy]-2-(2,2,2-trifluoroethyl)-2,3,4,5-tetrahydro-1H-2-benzazepine-4-acetic acid (compound 1), has been generated, which prevented net bone loss and inhibited cancellous bone turnover in vivo. The compound binds alpha(v)beta3 and the closely related integrin alpha(v)beta5 with low nanomolar affinity but binds only weakly to the related integrins alpha(IIb)beta3, and alpha5beta1. Compound 1 inhibited alpha(v)beta3-mediated cell adhesion with an IC50 = 3 nM. More importantly, the compound inhibited human osteoclast-mediated bone resorption in vitro with an IC50 = 11 nM. In vivo, compound 1 inhibited bone resorption in a dose-dependent fashion, in the acute thyroparathyroidectomized (TPTX) rat model of bone resorption with a circulating EC50 approximately 20 microM. When dosed orally at 30 mg/kg twice a day (b.i.d.) in the chronic ovariectomy (OVX)-induced rat model of osteopenia, compound 1 also prevented bone loss. At doses ranging from 3 to 30 mg/kg b.i.d., compound 1 partially prevented the OVX-induced increase in urinary deoxypyridinoline. In addition, the compound prevented the OVX-induced reduction in cancellous bone volume (BV), trabecular number (Tb.N), and trabecular thickness (Tb.Th), as assessed by quantitative microcomputerized tomography (microCT) and static histomorphometry. Furthermore, both the 10-mg/kg and 30-mg/kg doses of compound prevented the OVX-induced increase in bone turnover, as measured by percent osteoid perimeter (%O.Pm). Together, these data indicate that the alpha(v)beta3 antagonist compound 1 inhibits OVX-induced bone loss. Mechanistically, compound 1 prevents bone loss in vivo by inhibiting osteoclast-mediated bone resorption, ultimately preventing cancellous bone turnover.

Magnetic resonance microscopy in cardiac development

Magnetic resonance microscopy (MRM) is a fast and non-destructive imaging technique that can analyze the three-dimensional structure of the embryonic heart both qualitatively and quantitatively. Intravascular contrast agents have been developed to accentuate the anatomy of cardiac chambers, the cardiac outflow tract, and major arteries and veins throughout the embryonic body. MRM generates non-distorted three-dimensional data of vascular anatomy in a fraction of the time required by conventional optical image reconstruction techniques. The three-dimensional nature of these data allows the creation of visual models that can be manipulated for fast and easy interpretation of the complex relationships between heart chambers and aortic arches. This is particularly helpful because these relationships change in complex ways during development. The non-destructive nature of MRM makes it well suited for investigating rare or valuable specimens and live subjects. MRM techniques have been developed for imaging the embryo in utero and in vitro, although MRM studies of fixed embryo specimens are easier to perform and produce data with better contrast and higher resolution.

Platelet PlA2 polymorphism enhances risk of neurocognitive decline after cardiopulmonary bypass. Multicenter Study of Perioperative Ischemia (McSPI) Research Group

BACKGROUND

Neurocognitive decline, often produced by atherosclerotic plaque embolization, remains a frequent complication of cardiopulmonary bypass. Plaque fragments may initiate local thrombosis, which, in turn, aggravates the embolic insult. Prothrombotic genetic factors may exacerbate this process. We investigated whether the PlA2 polymorphism of platelet GPIIIa, a prothrombotic risk factor in other cardiovascular settings, is associated with early neurocognitive decline after cardiopulmonary bypass.

METHODS

Neurocognitive changes were evaluated by the Mini-Mental State Examination administered preoperatively and on postoperative day 4 and the PlA genotype determined in 70 patients undergoing cardiopulmonary bypass.

RESULTS

Forty-nine patients were PlA1/A1, and 21 were PlA1/A2 or PlA2/A2. Fifty-two patients (74%) demonstrated post-cardiopulmonary bypass neurocognitive decline, of which 34 were PlA1/A1 and 18 were PlA1/A2 or PlA2/A2 Multivariate analysis revealed that the PlA2 genotype and baseline Mini-Mental State Examination were significantly associated with greater neurocognitive decline (decreased Mini-Mental State Examination scores, p = 0.036 and 0.024, respectively).

CONCLUSIONS

This study demonstrates a link between the PlA2 allele of platelet GPIIIa and more severe neurocognitive decline after cardiopulmonary bypass. Although the mechanism is unknown, it could represent exacerbation of platelet-dependent thrombotic processes associated with plaque embolism.

Development of an in vivo preclinical screen model to estimate absorption and bioavailability of xenobiotics

The purpose of this study was to develop an in vivo screening method for rapid preclinical characterization of absorption and bioavailability of large numbers of compounds. This effort involved several steps. First, a pharmacokinetic characterization of a reference compound was conducted in the monkey. These data were used to verify theoretical calculations of a maximal portal dose-normalized area under the concentration-time curve. Next, a monkey screen was implemented using mixtures of up to five compounds each (i.e., cassettes) to estimate the bioavailability of approximately 200 compounds. Cassettes were administered as a single intraduodenal dose to a single monkey followed by simultaneous portal and systemic blood sampling. Definitive studies were then conducted to determine absolute bioavailability of 14 of these compounds. The studies with the reference compound demonstrated that the theoretical methodology based on a single intraduodenal dose with portal and systemic sampling provided consistent estimates of bioavailability. In the screen studies, approximately 75% of the test compounds were excluded from further evaluation due to poor absorption. Of the 14 compounds selected for follow-up evaluation from both well and poorly absorbed compounds, the absolute bioavailability of 10 of them were correctly classified from the screening data. The remaining 4 compounds were false positives, which showed low bioavailability; no false negatives were encountered. This approach allows for a rapid and reliable screen to evaluate absorption and bioavailability using a single dose in a preclinical model.

Epitope analysis of the human thyrotropin (TSH) receptor using monoclonal antibodies

A panel of thyrotropin (TSH) receptor (TSHR) monoclonal antibodies (mAbs), produced using highly purified Chinese hamster ovary (CHO) cell-produced TSHR, has been used to study TSHR structure. All 41 mAbs recognized full-length TSHR containing complex carbohydrate (120 kDa), and 40 mAbs recognized full-length precursor-containing high mannose sugars (100 kDa). The mAbs also recognized TSHR cleavage products with three types of reactivity: type 1 mAbs reacting with bands at 70 kDa and 58 kDa, type 2 with bands at 70 kDa and 52 kDa, and type 3 with bands at 52 kDa and 40 kDa. Deglycosylation studies showed that the 70-kDa and 58-kDa bands contained complex carbohydrate, whereas the 52-kDa and 40-kDa bands were unglycosylated. These results are consistent with TSHR cleavage occurring at two sites. Cleavage at both sites gives rise to glycosylated A subunit (58 kDa) corresponding to the extracellular domain of the receptor and nonglycosylated B subunit (40 kDa) corresponding to the C-terminal transmembrane domain. Cleavage only at site 1 gives rise to the 58-kDa A subunit and a large B subunit (52 kDa). Cleavage only at site 2 gives rise to a large A subunit (70 kDa) and the B subunit (40 kDa). Four of the mAbs inhibited 125I-labeled TSH binding to solubilized full-length TSHR. TSH binding was inhibited by (a) two type 3 mAbs reactive with the N-terminal region of the B subunit (epitopes between amino acids 381 and 385 and between 380 and 418, respectively) and (b) two type 2 mAbs reactive with epitopes on the A subunit (between amino acids 246 and 260). These results together with previous studies on the direct binding of TSH to the TSHR A subunit suggest that at least two distinct regions of the TSHR sequence, including one region on the A subunit and one region on the B subunit, fold together to form part of a complex TSH binding site.

Preexposure effects of nicotine and acetaldehyde on conditioned taste aversion induced by both drugs

Previous assessments have demonstrated an interaction between ethanol and nicotine in the conditioned taste-aversion (CTA) paradigm. The present study assessed whether acetaldehyde, the primary reinforcing metabolite of ethanol, would interact with nicotine as well. In six experiments, water-deprived male Wistar rats were preexposed to either acetaldehyde (0.2 or 0.3 g/kg, IP) or nicotine (0.8, 1.2, or 2 mg/kg, SC) for 3 consecutive days and then subsequently conditioned, 24 h later, with either nicotine (0.8, 1.2, or 2 mg/kg, SC) or acetaldehyde (0.2 or 0.3 g/kg, IP), respectively. There were 4 conditioning days and 4 drug-free test days, each spaced 72 h apart. On test days, animals were offered a free choice between water and saccharin. The results of the following set of experiments demonstrated a dose-related interaction between nicotine and acetaldehyde, where lower doses of each drug failed to attenuate CTA induced by one another, but a higher nicotine dose (2 mg/kg) attenuated the formation of a CTA induced by acetaldehyde (0.3 g/kg). It was argued that the primary metabolite of ethanol may play a role in the interaction between nicotine and ethanol previously observed.

Augmentation of corticosterone release by means of a caffeine-ethanol interaction in rats

We examined whether the acute treatment with caffeine delivered before an ethanol injection would augment plasma corticosterone (CORT) levels. The effect of caffeine on blood ethanol levels was also assessed. After 10 days of acclimatization to the colony room conditions, male Wistar rats were injected with either caffeine (5 mg/kg, ip) or saline 30 min before the delivery of ethanol (0.8 g/kg, ip) or saline, respectively. Trunk blood was then collected at 15 and 30 min after the ethanol injection for determination of plasma CORT and blood ethanol levels. CORT was measured with the use of radioimmunoassay, and blood ethanol levels were determined with the use of gas chromatography. The results showed that although caffeine and ethanol delivered singly failed to augment plasma CORT levels, the combination of both drugs produced elevations in plasma CORT levels at 15 and 30 min. These findings were found to be unrelated to changes in ethanol metabolism as caffeine failed to alter blood ethanol levels within the period tested. It was argued that the present elevations in plasma CORT levels observed in animals administered caffeine and ethanol may play a role in the caffeine-induced elevations in ethanol drinking observed elsewhere.

Caffeine promotes ethanol drinking in rats. Examination using a limited-access free choice paradigm

There is growing evidence that caffeine may alter the pattern of intake of a variety of drugs. The present study was designed to assess the effect of caffeine pretreatment on voluntary ethanol consumption. The first experiment examined the effect of caffeine on the acquisition of ethanol intake in a limited-access-choice procedure in which water and ethanol were presented concurrently. Male Wistar rats, exposed to food and water ad lib, were presented with a daily 1-h choice session between water and progressively increasing concentrations of ethanol (2-10%). Each ethanol concentration was made available for 4-6 days for a total of 20 days of access to ethanol. Intraperitoneal injections of caffeine (5 or 10 mg/kg) or saline were administered to the rats 30 min prior to each choice session. Caffeine produced a dose-related facilitation in ethanol drinking whereby the lower caffeine dose produced enhancement in ethanol drinking. The second experiment examined the effect of caffeine on the maintenance of established ethanol consumption. Male Wistar rats, initially acclimatized to increasing concentrations of ethanol (2%-10), were presented with an additional 18 ethanol (10%) presentations, comprised of a 6-day baseline period followed by 6 days of treatment where animals were given one of three doses of caffeine (2.5, 5 or 10 mg/kg) or saline prior to ethanol presentation. A final 6-day post-treatment period followed treatment. These results revealed an inverted-U effect of caffeine dose on ethanol ingestion where the low and high caffeine doses produced no effect but the moderate dose of 5 mg/kg enhanced ethanol drinking that persisted throughout the post-treatment period. A third experiment revealed that caffeine did not alter levels of blood ethanol within the time period used for the ethanol drinking session.

The effects of aminotriazole and acetaldehyde on an ethanol drug discrimination with a conditioned taste aversion procedure

The present study was designed to investigate whether acetaldehyde shares stimulus properties with ethanol using the conditioned taste aversion (CTA) baseline of drug discrimination learning. Animals were trained to discriminate ethanol (0.8 g/kg, i.p.) from saline using 11 consecutive cycles consisting of a pairing day and three nonpairing days. On pairing days, all animals were injected with ethanol 30 min prior to a 20-min limited access to a saccharin solution (0.1% w/v) and then immediately injected with either LiCl (0.15 M, 1.8 meq) or distilled water. On the three following nonpairing days, animals were injected with saline and 30 min later presented with the same saccharin solution for 20 min. No injections followed on these nonpairing days. Results showed that animals acquired discriminative stimulus control for ethanol after seven pairings. Pretreatment with the catalase inhibitor did not alter the discriminative control for ethanol. Generalization tests revealed that acetaldehyde substituted for ethanol at a dose of 0.3 g/kg. The results of the present study suggest that catalase inhibition did not reverse or alter the discriminative stimulus effects of ethanol. However, generalization tests showed that acetaldehyde (0.3 g/kg) will substitute for ethanol suggesting that these two drugs share some similar properties.

Antagonizing the parathyroid calcium receptor stimulates parathyroid hormone secretion and bone formation in osteopenic rats

Parathyroid hormone (PTH) is an effective bone anabolic agent, but it must be administered parenterally. An orally active anabolic agent would provide a valuable alternative for treating osteoporosis. NPS 2143 is a novel, selective antagonist (a "calcilytic") of the parathyroid cell Ca(2+) receptor. Daily oral administration of NPS 2143 to osteopenic ovariectomized (OVX) rats caused a sustained increase in plasma PTH levels, provoking a dramatic increase in bone turnover but no net change in bone mineral density. Concurrent oral administration of NPS 2143 and subcutaneous infusion of 17beta-estradiol also resulted in increased bone turnover. However, the antiresorptive action of estrogen decreased the extent of bone resorption stimulated by the elevated PTH levels, leading to an increase in bone mass compared with OVX controls or to either treatment alone. Despite the sustained stimulation to the parathyroid gland, parathyroid cells did not undergo hyperplasia. These data demonstrate that an increase in endogenous PTH secretion, induced by antagonism of the parathyroid cell Ca(2+) receptor with a small molecule, leads to a dramatic increase in bone turnover, and they suggest a novel approach to the treatment of osteoporosis.

Evaluation of the use of accelerated infusions for the determination of pharmacokinetic linearity

Accelerated infusions are potentially useful in the investigation of pharmacokinetic linearity. However, little information exists to validate this technique or to demonstrate its limitations. This investigation was performed to determine whether accelerated infusion regimens reliably estimate the range of pharmacokinetic linearity for molecules of varying pharmacokinetic properties, to evaluate the ability of accelerated infusions to identify pharmacokinetic nonlinearity, and to validate the accelerated infusion technique using compounds with known pharmacokinetic parameters. Simulations incorporating accelerated infusion as the input function resulted in the anticipated concentration-time profiles that contained an initial lag phase before reaching a linear slope. This lag phase increased with increasing distributional volume and in some instances was sufficiently great to obscure or prevent the linear portion of the profile. These simulations also revealed that clearance estimated from the apparently linear portion of the concentration-time profile can be erroneous under some conditions, as for large-volume compounds. Simulations of structured nonlinearity produced the predicted profiles for compounds with low to moderate volumes of distribution while demonstrating that modeling of data derived from compounds with large volumes of distribution may be inaccurate. Finally, experiments using accelerated infusions with various test compounds further demonstrated the usefulness of this technique while presenting limits imposed on the interpretation of the data. The results of this investigation indicate that the accelerated infusion may be used to determine pharmacokinetic linearity for compounds within certain pharmacokinetic boundaries, but that appropriate caution should be exercised in the extent of interpretation that should be extracted from such studies.

Inhibition of distal lung morphogenesis in Nkx2.1(-/-) embryos

In vitro and in vivo results are consistent with a critical role for NKX2.1, an epithelial homeodomain transcription factor in lung morphogenesis. Nkx2.1 null mutant embryos die at birth due to respiratory insufficiency caused by profoundly abnormal lungs. However, the precise role of NKX2.1 in the multistep process of lung structural morphogenesis and differentiation of various pulmonary cell types remains unknown. In the current study, we tested the hypothesis that the mutant lungs do not undergo branching morphogenesis beyond the formation of the mainstem bronchi and therefore consist solely of dilated tracheobronchial structures. To test this hypothesis, we determined the spatial and temporal expression pattern of a number of extracellular matrix (ECM) proteins and their cellular receptors, including alpha-integrins, laminin, and collagen type IV. Although laminin is expressed in the mutant Nkx2.1(-/-) lungs, expression of alpha-integrins and collagen type IV is significantly reduced or absent. In addition, examination of regionally specific expression of differentially spliced Vegf (vascular endothelial growth factor) transcripts, clearly indicates that the epithelial phenotype of the Nkx2.1(-/-) lungs is similar to the tracheobronchial epithelium. In contrast to wild-type lungs in which both Vegf1 and Vegf3 are developmentally expressed, Nkx2.1(-/-) lungs are characterized by predominant expression of Vegf1 and reduced or absent Vegf3. A similar pattern of Vegf expression is also observed in isolated tracheo-bronchial tissue. The sum of these findings suggest that at least two separate pathways may exist in embryonic lung morphogenesis: proximal lung morphogenesis is Nkx2.1 independent, while distal lung morphogenesis appears to be strictly dependent on the wild-type activity of Nkx2.1.

An in vitro study of the effect of bony buttressing on fixation strength of a fractured atrophic edentulous mandible model

PURPOSE

The purpose of this study was to measure the resistance to displacement in an adult bovine rib mandible model as the vertical dimension of the bone decreases, and to compare the fixation strength of titanium miniplates and reconstruction plates.

MATERIALS AND METHODS

Five groups of 6 ribs each were tested based on the vertical dimension of the rib and method of fixation (group 1, 40 mm, miniplate), (group 2, 30 mm, miniplate), (group 3, 20 mm, miniplate), (group 4, 10 mm, miniplate), (group 5, 10 mm, reconstruction plate). In the 4 groups stabilized with a miniplate, a 3-hole-per-segment, 2.0-mm titanium miniplate and 6.0-mm monocortical titanium screws were used. In group 5, a 3-screw-per-segment, 2.4-mm titanium reconstruction plate and 2.4-mm bicortical titanium screws were used for fixation. A 2-dimensional beam model (Class III lever) was established, and an Instron machine was used initially to develop a load-displacement curve to 100 N for each specimen. An osteotomy was then created, and the segments were reduced without preload. The ribs were then loaded to failure in the Instron machine. The load-displacement curve and failure load were recorded.

RESULTS

There was no significant difference (P < or = .05) between any of the groups before the osteotomy. At 75 N, groups 1 and 2 were superior to group 5 in resistance to displacement. Group 4 showed significantly less (P < or = .05) resistance to displacement than the other experimental miniplated subgroups. As loads increased, groups 1 and 2 continued to show increased resistance to displacement when compared with groups 3, 4, and 5. Loads to failure for groups 1 and 2 were comparable to group 5.

CONCLUSIONS

Decreased resistance to displacement occurs with decreasing vertical dimension of the bovine rib. In fractures of the edentulous mandible, a miniplate is more likely to provide adequate fixation if the mandible is 30 to 40 mm in height (nonatrophic). At higher loads, groups with greater vertical height (30 mm and 40 mm) provided resistance to displacement equivalent to the 10-mm group repaired with a reconstruction plate. Therefore, fractures of the atrophic mandible may be better treated with more rigid techniques.

Preclinical pharmacokinetics and interspecies scaling of a novel vitronectin receptor antagonist

Allometric scaling may be used in drug development to predict the pharmacokinetics of xenobiotics in humans from animal data. Although allometry may be successful for compounds that are excreted unchanged or that are oxidatively metabolized (with corrections for metabolic capacity), it has been more challenging for compounds excreted primarily as conjugates in bile. (S)-10, 11-Dihydro-3-[3-(pyridin-2-ylamino)-1-propyloxy]-5H-dibenzo[ a, d]cycloheptene-10-acetic acid (SB-265123) is a novel alphavbeta3 ("vitronectin receptor") antagonist. In this study, the in vivo pharmacokinetics and in vitro plasma protein binding of SB-265123 were examined in four species: mice, rats, dogs, and monkeys. In monkeys and dogs, SB-265123 exhibited moderate clearance, whereas low clearance (<20% hepatic blood flow) was observed in the rat, and high clearance (>70% hepatic blood flow) was seen in the mouse. The concentration-time profiles indicated the possibility of enterohepatic recirculation; subsequent studies in bile duct-cannulated rats demonstrated extensive biliary excretion of an acyl-glucuronide of SB-265123. In allometric scaling to predict the disposition of SB-265123 in humans, various standard correction factors were applied, including protein binding, maximum lifespan potential, and brain weight; each failed to produce adequate interspecies scaling of clearance (r(2) < 0.72). Consequently, a novel correction factor incorporating bile flow and microsomal UDP-glucuronosyltransferase activity in each species was applied, demonstrating substantial improvement in the correlation of the allometric plot (r(2) = 0.96). This study demonstrates a novel allometric correction that may be applicable to compounds that undergo conjugation and biliary excretion.

Design and characterization of orally active Arg-Gly-Asp peptidomimetic vitronectin receptor antagonist SB 265123 for prevention of bone loss in osteoporosis

The Arg-Gly-Asp (RGD)-binding integrin alpha(V)beta(3) is highly expressed on osteoclasts and has been proposed to mediate cell-matrix adhesion required for osteoclast-mediated bone resorption. Antagonism of this receptor should prevent stable osteoclast adhesion and thereby inhibit bone resorption. We have generated an orally bioavailable, nonpeptide RGD mimetic alpha(v)beta(3) antagonist, SB 265123, which prevents bone loss in vivo when dosed by oral administration. SB 265123 binds alpha(v)beta(3) and the closely related integrin alpha(v)beta(5) with high affinity (K(i) = 3.5 and 1.3 nM, respectively), but binds only weakly to the related RGD-binding integrins alpha(IIb)beta(3) (K(i) >1 microM) and alpha(5)beta(1) (K(i) >1 microM). The compound inhibits alpha(v)beta(3)-mediated cell adhesion with an IC(50) = 60 nM and more importantly, inhibits human osteoclast-mediated bone resorption in vitro with an IC(50) = 48 nM. In vivo, SB 265123 completely blocks bone resorption in a thyroparathyroidectomized rat model of acute bone resorption when dosed at 2.5 mg/kg/h by continuous i.v. infusion. When dosed orally with 3 to 30 mg/kg b.i.d. , in the ovariectomy-induced rat model of osteoporosis, SB 265123 prevents bone resorption in a dose-dependent fashion. This is the first report of an orally active alpha(v)beta(3) antagonist that is effective at inhibiting bone resorption when dosed in a pharmaceutically acceptable fashion. Such a molecule may provide a novel therapeutic agent for the treatment of postmenopausal osteoporosis.

The interaction of TSH receptor autoantibodies with 125I-labelled TSH receptor

Detergent-solubilized porcine TSH receptor (TSHR) has been labeled with 125I using a monoclonal antibody to the C-terminal domain of the receptor. The ability of sera containing TSHR autoantibody to immunoprecipitate the labeled receptor was then investigated. Sera negative for TSHR autoantibody (as judged by assays based on inhibition of labeled TSH binding to detergent-solubilized porcine TSHR) immunoprecipitated about 4% of the labeled receptor, whereas sera with high levels of receptor autoantibody immunoprecipitated more than 25% of the labeled receptor. The ability to immunoprecipitate labeled TSHR correlated well with ability of the sera to inhibit labeled TSH binding to the receptor (r = 0.92; n = 63), and this is consistent with TSHR autoantibodies in these samples being directed principally to a region of the receptor closely related to the TSH binding site. Preincubation of labeled TSHR with unlabeled TSH before reaction with test sera inhibited the immunoprecipitation reaction, providing further evidence for a close relationship between the TSHR autoantibody binding site(s) and the TSH binding site. This was the case whether the sera had TSH agonist (i.e., thyroid stimulating) or TSH antagonist (i.e., blocking) activities, thus, providing no clear evidence for different regions of the TSHR being involved in forming the binding site(s) for TSHR autoantibodies with stimulating and with blocking activities. The ability of TSHR autoantibodies to stimulate cyclic AMP production in isolated porcine thyroid cells was compared with their ability to immunoprecipitate labeled porcine TSHR. A significant correlation was observed (r = 0.58; n = 50; P < 0.001) and the correlation was improved when stimulation of cyclic AMP production was compared with inhibition of labeled TSH binding to porcine TSHR (r = 0.76). Overall, our results indicate that TSHR autoantibodies bind principally to a region on the TSHR closely related to the TSH binding site, and this seems to be the case whether the autoantibodies act as TSH agonists or antagonists.

Cocaine and ethanol interaction in the conditioned taste aversion paradigm

The aim of this study was to examine the relationship between cocaine and ethanol in a variant of the conditioned taste aversion (CTA) paradigm. The preexposure CTA procedure formed the basis of the following set of experiments. Experiments 1a and 1b assessed whether cocaine and ethanol were functionally related with overlapping stimulus properties as reflected in the preexposure CTA procedure. Male Wistar rats with restricted water access were preexposed to cocaine or ethanol for 3 consecutive days. Twenty-four hours after the last preexposure session, rats were conditioned to either ethanol or cocaine, respectively. The results of this set of experiments revealed a symmetrical interaction between cocaine and ethanol, where cocaine and ethanol effectively blocked CTA to one another. These findings suggested that there may be overlapping stimulus properties between cocaine and ethanol, which may be detected in this procedure.

Selective blockade of membrane attack complex formation during simulated extracorporeal circulation inhibits platelet but not leukocyte activation

OBJECTIVE

Complement activation is induced by cardiopulmonary bypass, and previous work found that late complement components (C5a, C5b-9) contribute to neutrophil and platelet activation during bypass. In the present study, we blocked C5b-9 formation during extracorporeal recirculation of whole blood to assess whether the membrane attack complex was responsible for both platelet and leukocyte activation.

METHODS

In a simulated extracorporeal model that activates complement (C3a and sC5b-9), platelets (CD62P expression, leukocyte-platelet conjugate formation), and leukocytes (increased CD11b expression and neutrophil elastase), we examined an anti-human C8 monoclonal antibody that inhibits C5b-9 generation for its effects on cellular activation.

RESULTS

Anti-C8 significantly inhibited sC5b-9 formation but did not block C3a generation. Anti-C8 also significantly inhibited the increase in platelet CD62P and monocyte-platelet conjugate formation seen with control circulation. Moreover, compared with control circulation, in which the number of circulating platelets fell by 45%, addition of anti-C8 completely preserved platelet counts. In contrast to blockade of both C5a and sC5b-9 during simulated extracorporeal circulation, neutrophil activation was not inhibited by anti-C8. However, circulating neutrophil and monocyte counts were preserved by addition of anti-C8 to the extracorporeal circuit.

CONCLUSIONS

The membrane attack complex, C5b-9, is the major complement determinant of platelet activation during extracorporeal circulation, whereas C5b-9 blockade has little effect on neutrophil activation. These data also suggest a role for platelet activation or C5b-9 (or both) in the loss of monocytes and neutrophils to the extracorporeal circuit.