The value of virtual biobanks for transparency purposes with respect to reagents and samples used during test development and validation.

Biobanks represent a valuable resource in many areas of biomedical research and development. They function as repositories for well-documented and well-characterised biological material that can be used as the basis for this work. Virtual biobanks amplify the availability of this resource by linking multiple biobanks via a single interface. Test development and validation is an essential process that helps to provide confidence in diagnostic test results and, by extension, the disease and health status of animal populations demonstrated by such results. The quality of the development and validation pathway can be enhanced by the use of well-characterised material for standards and validation panels. Virtual biobanks represent a powerful mechanism for enhancing access to such material, and allow other parties to both have greater confidence in the work done, and to be able to repeat it themselves, as required.

Les biobanques constituent une ressource précieuse dans un grand nombre de domaines de la recherche et du développement biomédicaux. Elles servent d'archives destinées au stockage de matériels biologiques suffisamment documentés et caractérisés pour être utilisés comme éléments de base dans ces domaines. Les biobanques virtuelles opèrent comme multiplicateurs des ressources disponibles en reliant plusieurs biobanques sur une même interface. La mise au point et la validation des tests constituent un processus essentiel qui contribue à asseoir la confiance dans les résultats d'un test et, par voie de conséquence, dans le statut sanitaire d'une population animale tel qu'il ressort de ces résultats. La qualité du processus de développement et de validation peut être améliorée en faisant appel à des matériels bien caractérisés en tant que panels de référence et de validation. Les biobanques virtuelles sont un mécanisme puissant pour améliorer l'accès à ce type de matériels et permettent à d'autres intervenants d'avoir une plus grande confiance dans les travaux réalisés, et de pouvoir eux-mêmes les répéter, si besoin.

Los biobancos constituyen un recurso muy útil en numerosas vertientes de la labor de investigación y desarrollo (I+D) en biomedicina. Estos bancos funcionan como repositorios de material biológico bien descrito y caracterizado que cabe utilizar como base de dicha labor. Los biobancos virtuales, al vincular entre sí múltiples biobancos por medio de una única interfaz, ponen este recurso al alcance de muchos más usuarios. La creación y validación de pruebas analíticas es un proceso esencial, que ayuda a ofrecer confianza en los resultados de una prueba de diagnóstico y, por extensión, en la condición sanitaria de las poblaciones animales que dichos resultados indican. Es posible conferir mayor calidad al procedimiento de creación y validación utilizando muestras biológicas bien caracterizadas como material de referencia y para establecer paneles de validación. Los biobancos virtuales, amén de constituir un potente mecanismo para mejorar el acceso a material biológico, infunden a terceras partes mayor confianza en la labor realizada y permiten a estas partes replicar por sí mismas el proceso de ser necesario.

Predicting population responses to environmental change from individual-level mechanisms: towards a standardized mechanistic approach.

Animal populations will mediate the response of global biodiversity to environmental changes. Population models are thus important tools for both understanding and predicting animal responses to uncertain future conditions. Most approaches, however, are correlative and ignore the individual-level mechanisms that give rise to population dynamics. Here, we assess several existing population modelling approaches and find limitations to both 'correlative' and 'mechanistic' models. We advocate the need for a standardized mechanistic approach for linking individual mechanisms (physiology, behaviour, and evolution) to population dynamics in spatially explicit landscapes. Such an approach is potentially more flexible and informative than current population models. Key to realizing this goal, however, is overcoming current data limitations, the development and testing of eco-evolutionary theory to represent interactions between individual mechanisms, and standardized multi-dimensional environmental change scenarios which incorporate multiple stressors. Such progress is essential in supporting environmental decisions in uncertain future conditions.

Probing the repulsive core of the nucleon-nucleon interaction via the (4)He(e,e'pN) triple-coincidence reaction.

We studied simultaneously the (4)He(e,e'p), (4)He(e,e'pp), and (4)He(e,e'pn) reactions at Q(2)=2(GeV/c)(2) and x(B)>1, for an (e,e'p) missing-momentum range of 400 to 830 MeV/c. The knocked-out proton was detected in coincidence with a proton or neutron recoiling almost back to back to the missing momentum, leaving the residual A=2 system at low excitation energy. These data were used to identify two-nucleon short-range correlated pairs and to deduce their isospin structure as a function of missing momentum, in a region where the nucleon-nucleon (NN) force is expected to change from predominantly tensor to repulsive. The abundance of neutron-proton pairs is reduced as the nucleon momentum increases beyond ∼500 MeV/c. The extracted fraction of proton-proton pairs is small and almost independent of the missing momentum. Our data are compared with calculations of two-nucleon momentum distributions in (4)He and discussed in the context of probing the elusive repulsive component of the NN force.

In vitro and in vivo effects of leukotriene B4 antagonism in a primate model of asthma.

To test the hypothesis that leukotriene (LT) B4 antagonists may be clinically useful in the treatment of asthma, CP-105,696 was evaluated in vitro, using chemotaxis and flow cytometry assays, and in vivo, using a primate asthma model. CP-105,696 inhibited LTB4-mediated monkey neutrophil chemotaxis (isolated cells, LTB4 = 5 nM) and CD11b upregulation (whole blood, LTB4 = 100 nM) with IC50 values of 20 nM and 16.5 microM, respectively. Using a modification of a previously described in vivo protocol (Turner et al. Am. J. Respir. Crit. Care Med. 1994. 149: 1153-1159), we observed that treatment with CP-105,696 inhibited the acute increase in bronchoalveolar lavage (BAL) levels of IL-6 and IL-8 by 56.9 +/- 13.2% and 46.9 +/- 14.5%, respectively, 4 h after challenge with Ascaris suum antigen (Ag). CP-105,696 tended to reduce the increase in BAL protein levels 0.5 h after Ag challenge by 47.5 +/- 18.3%, but this was not statistically significant. In addition, CP-105,696 prevented the significant 11-fold increase in airway responsiveness to methacholine after multiple Ag challenge. These results suggest that LTB4 partially mediates acute and chronic responses to antigen in an experimental primate asthma model and support the clinical evaluation of LTB4 antagonists in human asthma.

The effect of the NK1 receptor antagonist CP-99,994 on emesis and c-fos protein induction by loperamide in the ferret.

The site of the anti-emetic action of the neurokinin1 receptor antagonist CP-99,994 was studied in the ferret using the centrally acting opiate receptor agonist loperamide at a dose (0.5 mg/kg s.c.) which induced emesis in all animals tested. CP-99,994 (1 mg/kg, s.c.x2) abolished the emetic response (retching and vomiting) and the behaviours (licking, wet dog shakes, mouth scratching and gagging) induced by loperamide over a 2-h observation period. The enantiomer of this compound CP-100,263 (1 mg/kg, s.c.x2) did not have any significant effect on emesis or related behaviours. Loperamide (0.5 mg/kg s.c.) administration (but not its vehicle) resulted in dense fos-like immunoreactivity (FLI) mainly throughout the rostro-caudal extent of the nucleus tractus solitarius but not the area postrema. Although CP-99,994 (1 mg/kgx2) abolished the loperamide-induced emesis, it did not have any statistically significant effect on FLI in the brainstem. In loperamide and CP-100,263 (1 mg/kg, s.c.x2) treated animals FLI was comparable to that in animals treated with loperamide and CP-99,994. The results from this study taken together with those from previous studies indicate that loperamide exerts its emetic effect via nucleus tractus solitarius dendrites projecting into the area postrema. The lack of significant effect of CP-99,994 on the FLI induced by loperamide in this nucleus suggests that it is acting at a site "deep" in the nucleus tractus solitarius or elsewhere. The marked reduction in behaviours associated with loperamide administration by CP-99,994 provides a preliminary indication that NK1 receptor antagonist (as represented by CP-99,994) may in the clinic have effects on behaviours induced by emetic agents in addition to their previously described effects on retching and vomiting.

7-Oxo-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridines as novel inhibitors of human eosinophil phosphodiesterase.

High-throughput file screening against inhibition of human lung PDE4 led to the discovery of 3-ethyl-1-(4-fluorophenyl)-6-phenyl-7-oxo-4, 5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine (11) as a novel PDE4 inhibitor. Subsequent SAR development, using an eosinophil PDE assay, led to analogues up to 50-fold more potent than 11 with IC50 values of 0.03-1.6 microM. One such compound, CP-220,629 (22) (IC50 = 0.44 microM), was efficacious in the guinea pig aerosolized antigen induced airway obstruction assay (ED50 2.0 mg/kg, po) and demonstrated a significant reduction in eosinophil (55%), neutrophil (65%), and IL-1beta (82%) responses to antigen challenge in atopic monkeys (10 mg/kg, po).

Biarylcarboxylic acids and -amides: inhibition of phosphodiesterase type IV versus [3H]rolipram binding activity and their relationship to emetic behavior in the ferret.

In addition to having desirable inhibitory effects on inflammation, anaphylaxis, and smooth muscle contraction, PDE-IV inhibitors also produce undesirable side effects including nausea and vomiting. In general, compounds that inhibit PDE-IV also potently displace [3H]rolipram from a high-affinity binding site in rat cortex. While this binding site has not been identified, it has been proposed to be an allosteric binding site on the PDE-IV enzyme. Preliminary studies have suggested that the emetic potency of PDE-IV inhibitors is correlated with affinity for the brain rolipram binding site rather than potency at inhibiting PDE-IV enzyme activity. Efforts to eliminate the emetic potential of PDE-IV inhibitors were directed toward developing compounds with decreased [3H]rolipram binding affinity while retaining PDE-IV potency. Thus, a novel series of 4-(3-alkoxy-4-methoxyphenyl)benzoic acids and their corresponding carboxamides were prepared and evaluated for their PDE-IV inhibitory and rolipram binding site properties. Modification of the catechol ether moiety led to phenylbutoxy and phenylpentoxy analogues that provided the desired activity profile. Specifically, 4-[3-(5-phenylpentoxy)-4-methoxyphenyl]-2-methylbenzoic acid, 18, was found to exhibit potent PDE-IV inhibitory activity (IC50 0.41 microM) and possessed 400 times weaker activity than rolipram for the [3H]rolipram binding site. In vivo, compound 18 was efficacious in the guinea pig aerosolized antigen induced airway obstruction assay (ED50 8.8 mg/kg, po) and demonstrated a significant reduction in emetic side effects (ferret, 20% emesis at 30 mg/kg, po).

The effect of CP-99994 on the responses to provocative motion in the cat.

1. The NK1 receptor antagonist CP-99994 has been shown to prevent vomiting elicited by both peripherally and centrally acting emetogens in ferrets and dogs. These results have now been extended to another stimulus, provocative motion, and another species, the cat. 2. CP-99994 displaced [3H]-substance P from cat cortex with IC50 of 0.52 +/- 0.08 nM. Following s.c. administration, peak plasma drug levels were achieved at 30 min. The plasma drug half life was 1.4 h. 3. Subcutaneous administration of CP-99994 inhibited motion-induced vomiting in the cat with an ED50 of 144 micrograms kg-1 but did not change the epiphenomena associated with provocative motion in the cat over the dose range of 30 to 300 micrograms kg-1. The antiemetic effect of CP-99994 can be attributed to antagonism of the NK1 receptor because its enantiomer, CP-100,263, which is 900 fold weaker as an NK1 antagonist, had no effects on any response to provocative motion. 4. The inhibitory effect of CP-99994 on motion-induced retching and vomiting is consistent with a central site of antiemetic action, potentially at the level of the motor nuclei responsible for these behaviours. 5. An investigation into whether the failure of CP-99994 to alter the epiphenomena will also predict a lack of anti-nausea effects in man will provide critical information on the neural organization of the emetic reflex.

The anti-emetic effects of CP-99,994 in the ferret and the dog: role of the NK1 receptor.

1. The selective NK1 receptor antagonist, CP-99,994, produced dose-related (0.1-1.0 mg kg-1, s.c.) inhibition of vomiting and retching in ferrets challenged with central (loperamide and apomorphine), peripheral (CuSO4) and mixed central and peripheral (ipecac, cisplatin) emetic stimuli. 2. Parallel studies with the enantiomer, CP-100,263 (1 mg kg-1, s.c.), which is > 1,000 fold less potent as a NK1 antagonist, indicated that it was without significant effect against CuSO4, loperamide, cisplatin and apomorphine-induced emesis. Against ipecac, it inhibited both retching and vomiting, expressing approximately 1/10th the potency of CP-99,994. 3. The 5-HT3 receptor antagonist, tropisetron (1 mg kg-1, s.c.) inhibited retching and vomiting to cisplatin and ipecac, but not CuSO4 or loperamide. 4. CP-99,994 (1 mg kg-1, i.v.) blocked retching induced by electrical stimulation of the ventral abdominal vagus without affecting the cardiovascular response, the apnoeic response to central vagal stimulation or the guarding and hypertensive response to stimulation of the greater splanchnic nerves. CP-99,994 (1 mg kg-1, i.v.) did not alter baseline cardiovascular and respiratory parameters and it failed to block the characteristic heart rate, blood pressure and respiratory rate/depth changes in response to i.v. 2-methyl-5-HT challenge (von Bezold-Jarisch reflex). 5. Using in vitro autoradiography, [3H]-substance P was shown to bind to several regions of the ferret brainstem with the density of binding in the nucleus tractus solitarius being much greater than in the area postrema. This binding was displaced by CP-99,994 in a concentration-related manner. 6. In dogs, CP-99,994 (40 micrograms kg-1 bolus and 300 micrograms kg-1 h-1, i.v.) produced statistically significant reductions in vomiting to CuSO4 and apomorphine as well as retching to CuSO4. 7. Together, these studies support the hypothesis that the NK1 receptor antagonist properties of CP-99,994 are responsible for its broad spectrum anti-emetic effects. They also suggest that CP-99,994 acts within the brainstem, most probably within the nucleus tractus solitarius although the involvement of the area postrema could not be excluded.

Frequency dependence of CO2 elimination and respiratory resistance in monkeys.

In dogs, respiratory system resistance (Rrs) is frequency independent, and during high-frequency oscillatory ventilation (HFO) the relationship between CO2 elimination (VCO2) and frequency is linear. In contrast, we found in rabbits a large frequency-dependent decrease in Rrs with increasing frequency along with a nonlinear relationship between frequency and VCO2 (J. Appl. Physiol. 57: 354-359, 1984). We proposed that frequency dependent mechanical properties of the lung account for inter-species differences in the frequency dependence of gas exchange during HFO. In the current study we tested this hypothesis further by measuring VCO2 and Rrs as a function of frequency in a species of monkey (Macaca radiata). In these monkeys, Rrs decreased minimally between 4 and 8 Hz and in general increased at higher frequencies, whereas VCO2 was linearly related to frequency. This is further evidence supporting the hypothesis that nonlinear frequency-VCO2 behavior during HFO is related to frequency-dependent behavior in Rrs.

A model of constant-flow ventilation in a dog lung.

A semiempirical model of constant-flow ventilation (CFV) is developed to test the hypothesis that a three-zone serial model with the following characteristics can explain the adequate CO2 transport observed during CFV: 1) a zone of jet recirculation immediately downstream of the catheter in which convection dominates; 2) a zone influenced by turbulence but with little or no bulk flow; and 3) a peripheral zone, free of turbulence, in which transport is governed by molecular and augmented diffusion. Interactions between turbulent eddies and cardiogenic oscillations are included using a modification of Taylor dispersion theory according to the formulation of Kamm et al. Predicted values for arterial PCO2 are reasonably similar to experimental results for He-O2, air, and SF6-O2 mixtures for catheter flow rates from 0.2 to 1.6 l/s. Specific impedance to gas exchange was found to be largest immediately proximal to the end of turbulent mixing zone, where transport is governed by low-level eddy mixing and molecular diffusion. Simulations suggest that, during CFV, cardiogenic oscillations augment gas exchange primarily by promoting turbulent eddy dispersion in the distal airways and by extending the length of the turbulent mixing zone. Even small displacements of the catheter are shown to have a dramatic effect on gas exchange.

Effect of lung volume on pulmonary mechanics in guinea pigs.

The lung volume (VL) dependence of several dynamic pulmonary mechanical properties of the guinea pig lung were determined over the range of the vital capacity (10-100% VC) with the vagi intact and sectioned. We found dynamic compliance to be strongly VL dependent, decreasing as much as 85% between functional residual capacity (FRC) and total lung capacity (TLC). Below FRC, dynamic compliance either remained unchanged or decreased, depending upon the technique used in its measurement. Pulmonary resistance (RL) decreased monotonically with increasing VL, whereas pulmonary conductance was linearly related to VL. Conductance was much less sensitive to VL than compliance, increasing only 28% between FRC and TLC. The sensitivity of pulmonary conductance to VL was substantially increased by subtracting the resistance of the tracheal cannula from RL. Specific pulmonary conductance was not independent of VL but decreased approximately 45% over the range of the VC. Pulmonary inertance was found to be unaffected by VL. Extrapolation from these data indicate that small differences in FRC, which might be expected within and between studies relying on pulmonary mechanical measurements, would most strongly affect compliance estimates and only moderately alter resistance estimates. It also indicates that the use of specific pulmonary conductance does not remove VL as an independent variable.

The anti-emetic action of the neurokinin(1) receptor antagonist CP-99,994 does not require the presence of the area postrema in the dog.

Microinjection and ligand binding studies have implicated NK(1) receptors in the area postrema (AP) in the emetic response to intragastric copper sulphate that is mediated by abdominal vagal afferents. Because these afferents terminate in the brainstem in the nucleus tractus solitarius in close proximity to the AP or in the AP itself, the results of such studies may be difficult to interpret. The present study has demonstrated in the dog that the emetic response to intragastric copper sulphate is unaffected by AP ablation, demonstrated functionally by absence of an emetic response to apomorphine (100 microg kg(-1) i.v.). In AP ablated animals the selective NK(1) receptor antagonist CP-99, 994 (1 mg kg(-1) i.v.) blocked the emetic response to copper sulphate as it did in intact animals. The results demonstrate that the AP is not involved in the blockade of the emetic response to intragastric copper sulphate by an NK(1) receptor antagonist and hence provides further support for other sites proposed such as the nucleus tractus solitarius and central pattern generator.

Coronary artery atherosclerosis observed in men over 14 consecutive years.

The incidence of cardiovascular death and myocardial infarction associated with ischemic heart disease has declined over the past 15 years. Whether this is associated with a decrease in the severity of coronary atherosclerosis is unknown. The extent of coronary atherosclerosis in men was determined by postmortem coronary angiography in 505 patients over an observation period of 14 years. Patients were divided into those with ischemic heart disease (42%) and those without (58%). Mean coronary scores showed no significant trends over the 14-year period in those without ischemic heart disease and for the last 10 years in those with ischemic heart disease. In those few patients evaluated early in the study with ischemic heart disease, a significantly lower coronary score was found compared to subsequent years. This study was performed during an era of declining cardiovascular death rates and a declining incidence of myocardial infarction, and suggests that this decline may relate to favorable changes in pathogenesis rather than to a decrease in extent of coronary atherosclerosis.

High frequency jet ventilation in horses: an experimental study.

High frequency jet ventilation (HFJV) is a recently developed mode of ventilation that delivers small tidal volumes at frequencies greater than 60 cycles per min via an injection catheter to the animal's airway. The construction of a high frequency jet ventilator suitable for use in adult horses is described. The effectiveness of this ventilator in maintaining normal arterial blood-gas tension was evaluated in five healthy adult horses. The horses were anaesthetised with intravenous acetylpromazine, guaifenesin, and thiamylal, positioned in lateral recumbency and baseline measurements were made during spontaneous ventilation. The horses were then paralysed with succinylcholine and ventilated for at least 20 mins with HFJV. Air was delivered from the ventilator to the animal by a polyethylene tube. The tip of this tube remained within and approximately 30 cm from the cuffed end of a standard 30 mm internal diameter large animal orotracheal tube. Frequency of flow interruption was 3 Hz with a constant source pressure of 275 kPa and an inspiratory to expiratory ratio of approximately 1:2.6. Gas delivery to the horse, as estimated with a resonator system was approximately 2 litres/breath. During HFJV, arterial carbon dioxide tension was significantly reduced and arterial oxygen tension significantly increased above measurements made when the horses were spontaneously breathing air.

An evaluation of the contribution of the Swedish International Development Authority (SIDA) to leprosy control in India based on the implementation of multiple drug therapy (MDT) 1981-1993.

The Swedish International Development Authority (SIDA) first supported the National Leprosy Control Programme in India in 1978. In 1981/82 priority was given to the implementation of multiple drug therapy (MDT), starting in two high-endemic districts, and gradually extending to a total of 19 districts in the years by 1993. SIDA then decided to undertake a detailed evaluation of its 12-year contribution and this was carried out by an international team between November 1993 and April 1994. In terms of epidemiological and public health impact, the main results were impressive and clear-cut; 837,519 cases (old and newly arising) were successfully treated, with few complications and a low rate of relapse. The voluntary reporting rate had improved significantly. Data relating to new case detection, child and disability rates were, however, less clear and difficult to interpret. Deficiencies were also identified in the areas of health education, community participation, gender issues, disability prevention and management, rehabilitation, operational research and assessment of cost-effectiveness. These problems should not, however, detract from the contribution of SIDA, from 1981 onwards, in establishing the implementation of MDT in two 'pilot' districts at an early and important stage in the history of the MDT programme in India. SIDA also made significant contributions in other areas, namely pre-MDT 'screening' of registers in 45 endemic districts in 1990-1993, appointment of consultant leprologists at district level, group education activities, annual meetings of voluntary agencies and the development of a monitoring and information system, with computer facilities, at national level. This paper describes the design and methodology, main findings and conclusions of the evaluation, based on the final report and the appendices submitted to SIDA in Stockholm in April 1994.

Production of neutrons from interactions of GCR-like particles.

In order to help assess the risk to astronauts due to the long-term exposure to the natural radiation environment in space, an understanding of how the primary radiation field is changed when passing through shielding and tissue materials must be obtained. One important aspect of the change in the primary radiation field after passing through shielding materials is the production of secondary particles from the breakup of the primary. Neutrons are an important component of the secondary particle field due to their relatively high biological weighting factors, and due to their relative abundance, especially behind thick shielding scenarios. Because of the complexity of the problem, the estimation of the risk from exposure to the secondary neutron field must be handled using calculational techniques. However, those calculations will need an extensive set of neutron cross section and thicktarget neutron yield data in order to make an accurate assessment of the risk. In this paper we briefly survey the existing neutron-production data sets that are applicable to the space radiation transport problem, and we point out how neutron production from protons is different than neutron production from heavy ions. We also make comparisons of one the heavy-ion data sets with Boltzmann-Uehling-Uhlenbeck (BUU) calculations.