South American Dry Chaco rangelands: Positive effects of cattle trampling and transit on ecohydrological functioning

Livestock production in drylands requires consideration of the ecological applications of ecohydrological redistribution of water. Intensive cattle trampling and the associated increase of surface runoff are common concerns for rangeland productivity and sustainability. Here, we highlight a regional livestock production system in which cattle trails and trampling surrounding an artificial impoundment are purposely managed to enhance redistribution and availability of water for cattle drinking. Based on literature synthesis and field measurements, we first describe cattle production systems and surface water redistribution in the Dry Chaco rangelands of South America, and then develop a conceptual framework to synthesize the ecohydrological impacts of livestock production on these ecosystems. Critical to this framework is the pioshere-a degraded overgrazed and overtrampled area where vegetation has difficulties growing, usually close to the water points. The Dry Chaco rangelands have three key distinctive characteristics associated with the flat sedimentary environment lacking fresh groundwater and the very extensive ranching conditions: (1) cattle drinking water is provided by artificial impoundments filled by runoff, (2) heavy trampling around the impoundment and its adjacent areas generates a piosphere that favors runoff toward the impoundment, and (3) the impoundment, piosphere, and extensive forage areas are hydrologically connected with a network of cattle trails. We propose an ecohydrological framework where cattle transit and trampling alter the natural water circulation of these ecosystems, affecting small fractions of the landscape through increased runoff (compaction in piosphere and trails), surface connectivity (convergence of trails to piosphere to impoundment), and ponding (compaction of the impoundment floor) that operate together making water harvesting and storage possible. These effects have likely generated a positive water feedback on the expansion of livestock in the region with a relatively low impact on forage production. We highlight the role of livestock transit as a geomorphological agent capable of reshaping the hydrology of flat sedimentary rangelands in ways that can be managed positively for sustainable ranching systems. We suggest that the Dry Chaco offers an alternative paradigm for rangelands in which cattle trampling may contribute to sustainable seminatural production systems with implications for other dry and flat rangelands of the world.

Acceptability of delivering an adapted Buurtzorg model in the Scottish care context

OBJECTIVES

Given increasing epidemiological and financial pressures on services, there is a need to test new models of integrated health and social care. Crucial to this testing is determining acceptability, particularly to those delivering services. The Dutch 'Buurtzorg' model, characterised by self-managing nursing teams, has shown promise, but its principles are yet to be adapted and tested in Scotland. The study aim was to understand the experiences of working in a self-managing, integrated, health and social care team.

STUDY DESIGN

This is a case study within a primary care setting.

METHODS

The Integrated Neighbourhood Care Aberdeen (INCA) project comprised two self-managing teams of support workers and nurses working at different sites in Aberdeen. Acceptability was explored through semistructured interviews with staff. Data were recorded and analysed thematically.

RESULTS

Staff reported high-quality patient care, which they attributed to autonomy over the frequency and duration of visits. Tensions between team members and between teams and management were apparent partly due to the predominantly social care caseload, confounding guidance on how to implement self-management and communication challenges. The team colocated within a General Practice reported positive relationships with other professionals.

CONCLUSIONS

Self-management requires a clear framework in which to function. Allowing staff autonomy to vary care provision according to need may improve patient outcomes.

Effectiveness of interferon-free therapy for the treatment of HCV-patients with compensated cirrhosis treated through the Irish early access program

BACKGROUND

We investigated the real-world effectiveness of interferon-free regimens for the treatment of patients with compensated cirrhosis infected with hepatitis C virus (HCV).

METHOD

Using the Irish national HCV treatment registry, the effectiveness and safety of interferon-free regimens for HCV-infected patients treated between April 2015 and August 2016, was determined.

RESULTS

A SVR12 was achieved in 86% of subjects treated with sofosbuvir/ledipasvir ± ribavirin (SOF/LDV±RBV), 93% treated with paritaprevir, ombitasvir and ritonavir combined with dasabuvir ± ribavirin (3D±RBV) and 89% treated with sofosbuvir/daclatasvir ± ribavirin (SOF/DCV±RBV). The discontinuation rate was 5% and the on-treatment mortality rate was 1%.

CONCLUSION

The availability of interferon-free regimens represents a significant breakthrough for the treatment of HCV infection. Treatments options, with high SVR12 rates, are now available for patients with compensated cirrhosis who were unsuitable for treatment with interferon-based regimens. Data obtained from studies conducted in real world practice provide robust information fundamental for input into future economic evaluations for agents used for the treatment of HCV infection.

Evaluation of the effectiveness of air pollution control measures in Hong Kong

From 2005 to 2013, volatile organic compounds (VOCs) and other trace gases were continuously measured at a suburban site in Hong Kong. The measurement data showed that the concentrations of most air pollutants decreased during these years. However, ozone (O₃) and total non-methane hydrocarbon levels increased with the rate of 0.23 ± 0.03 and 0.34 ± 0.02 ppbv/year, respectively, pointing to the increasing severity of photochemical pollution in Hong Kong. The Hong Kong government has ongoing programs to improve air quality in Hong Kong, including a solvent program implemented during 2007-2011, and a diesel commercial vehicle (DCV) program since 2007. From before to after the solvent program, the sum of toluene, ethylbenzene and xylene isomers decreased continuously with an average rate of -99.1 ± 6.9 pptv/year, whereas the sum of ethene and propene increased by 48.2 ± 2.0 pptv/year from before to during the DCV program. Despite this, source apportionment results showed that VOCs emitted from diesel exhaust decreased at a rate of -304.5 ± 17.7 pptv/year, while solvent related VOCs decreased at a rate of -204.7 ± 39.7 pptv/year. The gasoline and liquefied petroleum gas vehicle emissions elevated by 1086 ± 34 pptv/year, and were responsible for the increases of ethene and propene. Overall, the simulated O₃ rate of increase was lowered from 0.39 ± 0.03 to 0.16 ± 0.05 ppbv/year by the solvent and DCV programs, because O₃ produced by solvent usage and diesel exhaust related VOCs decreased (p < 0.05) by 0.16 ± 0.01 and 0.05 ± 0.01 ppbv/year between 2005 and 2013, respectively. However, enhanced VOC emissions from gasoline and LPG vehicles accounted for most of the O₃ increment (0.09 ± 0.01 out of 0.16 ± 0.05 ppbv/year) in these years. To maintain a zero O₃ increment in 2020 relative to 2010, the lowest reduction ratio of VOCs/NOx was ∼1.5 under the NOx reduction of 20-30% which was based on the emission reduction plan for Pearl River Delta region in 2020.

Vegetation Productivity in Natural vs. Cultivated Systems along Water Availability Gradients in the Dry Subtropics

The dry subtropics are subject to a rapid expansion of crops and pastures over vast areas of natural woodlands and savannas. In this paper, we explored the effect of this transformation on vegetation productivity (magnitude, and seasonal and long-term variability) along aridity gradients which span from semiarid to subhumid conditions, considering exclusively those areas with summer rains (>66%). Vegetation productivity was characterized with the proxy metric “Enhanced Vegetation Index” (EVI) (2000 to 2012 period), on 6186 natural and cultivated sampling points on five continents, and combined with a global climatology database by means of additive models for quantile regressions. Globally and regionally, cultivation amplified the seasonal and inter-annual variability of EVI without affecting its magnitude. Natural and cultivated systems maintained a similar and continuous increase of EVI with increasing water availability, yet achieved through contrasting ways. In natural systems, the productivity peak and the growing season length displayed concurrent steady increases with water availability, while in cultivated systems the productivity peak increased from semiarid to dry-subhumid conditions, and stabilized thereafter giving place to an increase in the growing season length towards wetter conditions. Our results help to understand and predict the ecological impacts of deforestation on vegetation productivity, a key ecosystem process linked to a broad range of services.

The appropriateness of a proton pump inhibitor prescription

Proton pump inhibitors (PPIs) are one of the most commonly prescribed groups of drug in Ireland, at great expense to the Irish healthcare executive. This study aims to evaluate the appropriateness of PPI prescriptions on admission and discharge in a tertiary referral hospital. All non-elective admissions in the Emergency Department in one week were included in the study. 102 patients in total were included, with 36 (35.4%) treated with a PPI on admission. Of these, only 3 (8.3%) had a clear indication noted as per current NICE guidelines. 18 new in-hospital PPI prescriptions were documented. 11 (61%) of which were present on discharge prescriptions. Continuing PPI prescription on discharge into the community may be inappropriate, costly and potentially harmful. Brief interventions aimed at reducing inappropriate PPI prescriptions have been shown to be effective at reducing the cost and potential harm of unnecessary treatment.

"Bending the cost curve" in gastroenterology

INTRODUCTION

Increasing attention is being focused on reigning in escalating costs of healthcare, i.e. trying to 'bend the cost curve'. In gastroenterology (GI), inpatient hospital care represents a major component of overall costs. This study aimed to characterize the trend in cost of care for GI-related hospitalizations in recent years and to identify the most costly diagnostic groups.

METHODS

All hospital inpatients admitted between January 2008 and December 2009 with a primary diagnosis of one of the six most common GI-related Diagnosis Related Groups (DRGs) in this hospital system were identified; all DRGs contained at least 40 patients during the study period. Patient Level Costing (PLC) was used to express the total cost of hospital care for each patient; PLC comprised a weighted daily bed cost plus cost of all medical services provided (e.g., radiology, pathology tests) calculated according to an activity-based costing approach; cost of medications were excluded. All costs were discounted to 2009 values. Mean length of stay (LOS) was also calculated for each DRG.

RESULTS

Over 2 years, 470 patients were admitted with one of the six most common GI DRGs. Mean cost of care increased from 2008 to 2009 for all six DRGs with the steepest increases seen in 'GI hemorrhage (non-complex)' (31 % increase) and 'Cirrhosis/Alcoholic hepatitis (non-complex)' (45 % increase). No differences in readmission rates were observed over time. There was a strong correlation between year-to-year change in costs and change in mean LOS, r = 0.93.

CONCLUSION

The cost of GI-related inpatient care appears to be increasing in recent years with the steepest increases observed in non-complex GI hemorrhage and non-complex Cirrhosis/Alcoholic hepatitis. Efforts to control the increasing costs should focus on these diagnostic categories.

Randomized controlled trial of feedback on cost of hospital care among gastroenterology inpatients

INTRODUCTION

Spending on hospital inpatients comprises a major proportion of healthcare costs. This study assessed the impact of systematic feedback to gastroenterologists on the cost of care provided to inpatients on a gastrointestinal/hepatology (GIH) hospital service.

METHODS

Patients with a GIH diagnosis were randomly assigned to be cared for by one of two hospital services. Over 3 months, teams were randomized to receive feedback (GIH A) or no feedback (GIH B, control group); feedback consisted of an email sent twice weekly to all physicians on the GIH A service detailing the length of stay (LOS) and real-time cost of care accrued by each inpatient.

RESULTS

Over 3 months, care was provided to 56 (GIH A) and 47 (GIH B) inpatients with a GIH illness. Patient complexity level was similar for both services as demonstrated by mean relative value: 1.11 (GIH A) vs. 1.27 (GIH B), p=0.2. Weighted LOS and weighted cost of care values were calculated to adjust for the respective RV of each patient. Mean weighted LOS (10.8 [GIH A] vs. 13.8 days/pt [GIH B], p=0.02) and mean weighted cost of care (9,904 [GIH A] vs. 12,654 euros/pt [GIH B], p=0.02) were significantly lower in the feedback group. Subsequent hospital readmission rates did not differ among both groups.

CONCLUSION

Systematic feedback on cost of care was associated with lower healthcare costs without compromising quality. Incorporating a running total of patient costs into computer software used to order patient tests may represent one approach to controlling healthcare expenses.

GPCR expression in tissues and cells: are the optimal receptors being used as drug targets?

G-protein-coupled receptors [GPCRs, also known as 7-transmembrane (7-TM) receptors] comprise the largest family of membrane receptors in humans and other species and, in addition, represent the greatest number of current drug targets. In this article, we review methods to define GPCR expression and data indicating that individual cells express >100 different GPCRs. Results from studies that have quantified expression of these receptors lead us to conclude that the optimal GPCRs may not be currently used as therapeutic targets. We propose that studies of GPCR expression in individual cells will likely reveal new insights regarding cellular physiology and therapeutic approaches. Findings that define and characterize the most highly expressed GPCRs thus have important potential in terms of identifying new drug targets and novel therapies directed at a wide range of clinical disorders.

Spontaneous firing in C-fibers and increased mechanical sensitivity in A-fibers of knee joint-associated mechanoreceptive primary afferent neurones during MIA-induced osteoarthritis in the rat

OBJECTIVE

Osteoarthritis (OA) pain mechanisms are poorly understood. We used the monosodium iodoacetate (MIA) model of knee OA to characterize changes in excitability during the course of OA in different classes of mechanosensitive afferents projecting to joint-associated tissues, and examine whether these afferent responses and pain behavior are correlated.

METHODS

Rats were injected intra-articularly with MIA (1mg in 50 μl). Hind-limb weight bearing was studied 3 (MIA3) and 14 (MIA14) days after MIA, followed by deep anesthesia and teased-nerve-fiber recordings. Spontaneous activity (SA) and mechanically evoked responses of A- and C-mechanosensitive fibers (AM and CM respectively, probably nociceptive) innervating tissues associated with the ipsilateral knee joint were examined.

RESULTS

MIA3 and MIA14 rats exhibited reduced ipsilateral weight bearing. SA (>0.02 impulses/s) occurred in ∼50% of CMs from MIA rats vs 0% in normals. SA firing rates in CMs were significantly higher than normal; decreased weight bearing was correlated with increased CM SA rates. Neither percentages of AMs with SA (20%) nor their firing rates (0-0.01 impulses/s) significantly increased after MIA. In contrast, in MIA rats AMs, but not CMs, exhibited decreased mechanical thresholds and increased firing rates in response to suprathreshold mechanical stimulation.

CONCLUSIONS

These findings of increased SA firing rate in CMs but not AMs and increased mechanical sensitivity of AMs, but not CMs, have not previously been reported. These are two distinct important physiological mechanisms that may underpin spontaneous pain (CMs) and stimulus-evoked pain (AMs) in OA. Our data contribute to a mechanism-based understanding of OA pain.

Cyclic AMP is both a pro-apoptotic and anti-apoptotic second messenger

The second messenger cyclic AMP (cAMP) can either stimulate or inhibit programmed cell death (apoptosis). Here, we review examples of cell types that show pro-apoptotic or anti-apoptotic responses to increases in cAMP. We also show that cells can have both such responses, although predominantly having one or the other. Protein kinase A (PKA)-promoted changes in phosphorylation and gene expression can mediate pro-apoptotic responses, such as in murine S49 lymphoma cells, based on evidence that mutants lacking PKA fail to undergo cAMP-promoted, mitochondria-dependent apoptosis. Mechanisms for the anti-apoptotic response to cAMP likely involve Epac (Exchange protein activated by cAMP), a cAMP-regulated effector that is a guanine nucleotide exchange factor (GEF) for the low molecular weight G-protein, Rap1. Therapeutic approaches that activate PKA-mediated pro-apoptosis or block Epac-mediated anti-apoptotisis may provide a means to enhance cell killing, such as in certain cancers. In contrast, efforts to block PKA or stimulate Epac have the potential to be useful in diseases settings (such as heart failure) associated with cAMP-promoted apoptosis.

Role of phosphodiesterases in adult-onset pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is characterized by increased mean pulmonary artery pressure (mPAP) due to vasoconstriction and structural changes in the small pulmonary arteries (PAs); proliferation of pulmonary artery smooth muscle cells (PASMCs) contributes to the remodeling. The abnormal pathophysiology in the pulmonary vasculature relates to decreased cyclic nucleotide levels in PASMCs. Phosphodiesterases (PDEs) catalyze the hydrolysis of cAMP and cGMP, thereby PDE inhibitors are effective in vasodilating the PA and decreasing PASMC proliferation. Experimental studies support the use of PDE3, PDE5, and PDE1 inhibitors in PAH. PDE5 inhibitors such as sildenafil are clinically approved to treat different forms of PAH and lower mPAP, increase functional capacity, and decrease right ventricular hypertrophy, without decreasing systemic arterial pressure. New evidence suggests that the combination of PDE inhibitors with other therapies for PAH may be beneficial in treating the disease. Furthermore, inhibiting PDEs in the heart and the inflammatory cells that infiltrate the PA may offer new targets to reduce right ventricular hypertrophy and inhibit inflammation that is associated with and contributes to the development of PAH. This chapter summarizes the advances in the area and the future of PDEs in PAH.

Human IgG antibody profiles differentiate between symptomatic patients with and without colorectal cancer

OBJECTIVE

Patients with cancer have antibodies against tumour antigens. Characterising the antibody repertoire may provide insights into aberrant cellular mechanisms in cancer development, ultimately leading to novel diagnostic or therapeutic targets. The aim of this study was to characterise the antibody profiles in patients whose symptoms warranted colonoscopy, to see if there was a difference in patients with and without colorectal cancer.

METHODS

Patients were recruited from a colonoscopy clinic. Individual serum samples from 43 patients with colorectal cancer and 40 patients with no cancer on colonoscopy were profiled on a 37 830 clone recombinant human protein array. Antigen expression was evaluated by quantitative reverse transcription-PCR and by immunohistochemistry on tissue microarrays.

RESULTS

Using a sex- and age-matched training set, 18 antigens associated with cancer and 4 associated with the absence of cancer (p<0.05) were identified and confirmed. To investigate the mechanisms triggering antibody responses to these antigens, antigen expression was examined in normal colorectal mucosa and colorectal carcinoma of the same patients. The identified antigens showed cellular accumulation (p53), aberrant cellular expression (high mobility group B1 (HMGB1)) and overexpression (tripartite motif-containing 28 (TRIM28), p53, HMGB1, transcription factor 3 (TCF3), longevity assurance gene homologue 5 (LASS5) and zinc finger protein 346 (ZNF346)) in colorectal cancer tissue compared with normal colorectal mucosa.

CONCLUSIONS

It is demonstrated for the first time that screening high-density protein arrays identifies unique antibody profiles that discriminate between symptomatic patients with and without colorectal cancer. The differential expression of identified antigens suggests their involvement in aberrant cellular mechanisms in cancer.

Cellular and histopathological changes in the infrapatellar fat pad in the monoiodoacetate model of osteoarthritis pain

OBJECTIVE

The infrapatellar fat pad (IPFP) has been identified as a source of anterior knee pain. Fibrosis and marked inflammatory infiltrate in the IPFP of patients with arthritis of the knee and reduction in pain post knee replacement in patients following resection of the IPFP have been observed. We have investigated changes in the IPFP of rats undergoing the monoiodoacetate (MIA) model of degenerative joint disease, a model that exhibits some histopathological similarities to osteoarthritis (OA).

METHODS

Rats were injected intra-articularly with MIA and the development of weight bearing asymmetry was followed for 21 days as compared to vehicle-injected animals. In addition, IPFPs were removed from both ipsilateral and contralateral joints. Both inflammatory infiltrate and histopathological changes were analysed.

RESULTS

MIA injection caused marked weight bearing asymmetry. Ipsilateral IPFP wet weights were significantly increased on days 1 and 3 in MIA-treated animals. MIA treatment also resulted in significant increases in IPFP total white blood cells and monocytes on days 1, 3, and 7 and neutrophils on days 1 and 3. This was supported by histopathological findings at early time points which progressed to adipocyte necrosis, IPFP fibrosis, patellar cartilage and subchondral bone necrosis with synovial hyperplasia at later timepoints.

CONCLUSIONS

The current study clearly demonstrated that marked inflammatory changes in the IPFP occur during the early stage of the MIA model of OA which may contribute to the pain observed at this early stage. The role of the IPFP in later stages of the model needs to be further explored.

Potential impact of enhanced practice efficiency on endoscopy waiting times

BACKGROUND

With the growing demand on endoscopy services, optimising practice efficiency has assumed increasing importance. Prior research has identified practice changes, which increase the efficiency in endoscopy. In this study, the potential impact of these practice changes on the current and projected future endoscopy waiting times at our institution was assessed.

METHODS

The annual volume of endoscopic procedures performed at a major teaching hospital and the annual procedure demand from 2000 to 2007 were reviewed. Procedure demand and waiting times were projected until 2012. The impact of three practice changes, which have been shown to increase efficiency was assessed: 1. routinely obtaining i.v. access and consent in patients prior to endoscopy (approach 1); 2. routinely obtaining i.v. access and consent, and sedating the patient prior to endoscopy (approach 2); 3. utilizing a two-room per endoscopist model (approach 3).

RESULTS

There has been a significant increase in annual procedure volume (36%) and annual procedure demand (69%) from 2000 to 2007. Annual waiting times for routine procedures have lengthened, from 6 weeks (2000) to 22 weeks (2007). Assuming continued linear growth in demand up to 2012, the projected waiting times will continue to rise reaching 40 weeks in 2012. Routinely obtaining i.v. access/consent prior to procedure (approach 1) would shorten the average routine waiting times so that 8 weeks (recommended HSE maximum) would not be exceeded until early 2006; routinely obtaining i.v. access/consent and sedating patient prior to procedure (approach 2) would shorten the average routine waiting time so that 8 weeks would not be exceeded until 2008; utilising two rooms per endoscopist (approach 3) would shorten the average routine waiting time so that 8 weeks would not be exceeded until early 2012.

CONCLUSIONS

Maintaining timely access to endoscopic services is becoming more challenging in the face of growing demand. Modifications in routine clinical practice can significantly impact procedure waiting times. In an era where economic aspects of medical care are becoming increasingly important and where there is growing focus on waiting times as a measure of clinical performance, these findings underscore the importance of providing clinical care in the most efficient manner possible.

Assessment of adherence to published surveillance guidelines--opportunity to enhance efficiency of endoscopic practice

Strict adherence to recommended surveillance intervals is important in ensuring timely access for patients awaiting endoscopy. This study aimed to characterise adherence rates to surveillance endoscopy guidelines. All surveillance procedures scheduled between January and December 2006 were reviewed. Surveillance procedures were classified as: a) Barrett's oesophagus, b) chronic IBD, c) prior adenomatous colorectal polyps and, d) prior surgical resection of colorectal cancer. 441 endoscopies were scheduled for surveillance of which 195 (44.2%) were scheduled at an inappropriate interval; all were scheduled prematurely. Of these, 50 of 133 (37.6%) Barrett's patients, 92 of 213 (43.2%) patients with prior colonic polyps, 36 of 48 (75.0%) patients with prior colonic malignancy and 17 of 47 (36.2%) patients for IBD surveillance were scheduled prematurely. Almost half of all surveillance procedures were scheduled inappropriately early. This 'over-surveillance' represents an unnecessary additional burden on the current endoscopic workload.

Evaluation of formal feedback on endoscopic competence among trainees: the EFFECT trial

INTRODUCTION

The medical literature describes disparity in colonoscopy performance. This randomised, controlled study aimed to characterise the impact of feedback on colonoscopy performance among gastroenterology (GI) trainees.

METHODS

Gastroenterology trainees of similar experience levels who independently performed 581 colonoscopies over the study period were randomised to receive feedback/no feedback on their colonoscopy performance.

RESULTS

Baseline colonoscopy performance was similar in both groups. Following feedback, caecal intubation improved by 10.5% (from 72.9 to 83.4%, p = 0.04) in the feedback group and declined by 6.1% (from 78 to 71.9%, p = 0.2) in the control group; polyp detection improved by 5.1% (from 12.9 to 18.0%, p = 0.2) in the feedback group and by 2.9% (from 16.7 to 19.6%, p = 0.5) in the control group.

CONCLUSIONS

Systematic feedback appears to enhance colonoscopy performance among GI trainees.

Assessment of colorectal cancer knowledge and patient attitudes towards screening: is Ireland ready to embrace colon cancer screening?

INTRODUCTION

The level of awareness among the Irish public regarding colorectal cancer (CRC) remains uncertain. This study aimed to characterise CRC knowledge levels among a cohort of Irish patients.

METHODS

A survey evaluating CRC knowledge levels was distributed among outpatients at a gastroenterology clinic in a Dublin teaching hospital.

RESULTS

In total, 472 surveys were distributed of which 465 (98.5%) were returned. Twenty-nine percent of respondents correctly judged CRC to be the commonest cause of cancer death among the options provided while 26% correctly judged the lifetime risk of CRC; 59% underestimated and 15% overestimated the risk. Most patients (91%) were willing to pay 300 euros for a prompt colonoscopy if recommended by their physician while 7% opted to wait 6 months for a free colonoscopy.

CONCLUSIONS

There is a willingness to embrace CRC screening and to shoulder some of the financial burden that this entails.

G-protein-coupled receptor-signaling components in membrane raft and caveolae microdomains

The efficiency of signal transduction in cells derives in part from subcellular, in particular plasma membrane, microdomains that organize signaling molecules and signaling complexes. Two related plasma membrane domains that compartmentalize G-protein coupled receptor (GPCR) signaling complexes are lipid (membrane) rafts, domains that are enriched in certain lipids, including cholesterol and sphingolipids, and caveolae, a subset of lipid rafts that are enriched in the protein caveolin. This review focuses on the properties of lipid rafts and caveolae, the mechanisms by which they localize signaling molecules and the identity of GPCR signaling components that are organized in these domains.

The BCL-2 promoter (-938C>A) polymorphism does not predict clinical outcome in chronic lymphocytic leukemia

The (-938C>A) polymorphism in the promoter region of the BCL-2 gene was recently associated with inferior time to treatment and overall survival in B-cell chronic lymphocytic leukemia (CLL) patients displaying the -938A/A genotype and may thus serve as an unfavorable genetic marker in CLL. Furthermore, the -938A/A genotype was associated with increased expression of Bcl-2. To investigate this further, we analyzed the -938 genotypes of the BCL-2 gene in 268 CLL patients and correlated data with treatment status, overall survival and known prognostic factors, for example, Binet stage, immunoglobulin heavy-chain variable (IGHV) mutational status and CD38 expression. In contrast to the recent report, the current cohort of CLL patients showed no differences either in time to treatment or overall survival in relation to usage of a particular genotype. In addition, no correlation was evident between the (-938C>A) genotypes and IGHV mutational status, Binet stage or CD38. Furthermore, the polymorphism did not appear to affect the Bcl-2 expression at the RNA level. Taken together, our data do not support the use of the (-938C>A) BCL-2 polymorphism as a prognostic marker in CLL and argue against its postulated role in modulating Bcl-2 levels.

The relationship between changes in daily air pollution and hospitalizations in Perth, Australia 1992-1998: a case-crossover study

A case-crossover study was undertaken to investigate the relationship between daily air pollutant concentrations and daily hospitalizations for selected disease categories in Perth, Western Australia. Daily measurements of particles (measured by nephelometry and PM2.5), photochemical oxidants (measured as ozone), nitrogen dioxide (NO2) and carbon monoxide (CO) concentrations were obtained from 1992 to 1998 via a metropolitan network of monitoring stations. Daily PM2.5 concentrations were estimated using monitored data, modelling and interpolation. Hospital morbidity data for respiratory, cardiovascular (CVD), gastrointestinal (GI) diseases, chronic obstructive pulmonary diseases (COPD) excluding asthma; pneumonia/influenza diseases; and asthma were obtained and categorized into all ages, less than 15 years and greater than 65 years. Gastrointestinal morbidity was used as a control disease. The data were analyzed using conditional logistic regression. The results showed a small number of significant associations for daily changes in particle concentrations, nitrogen dioxide and carbon monoxide for the respiratory diseases, CODP, pneumonia, asthma and CVD hospitalizations. Changes in ozone concentrations were not significantly associated with any disease outcomes. These data provide useful information on the potential health impacts of air pollution in an airshed with very low sulphur dioxide concentrations and lower nitrogen dioxide concentrations commonly found in many other cities.

Determination of guinea-pig cortical gamma-secretase activity ex vivo following the systemic administration of a gamma-secretase inhibitor

(2S)-2-{[(3,5-Diflurophenyl)acetyl]amino}-N-[(3S)-1-methyl-2-oxo-5-phenyl-2,3-dihydro-1H-1,4-benzodiazepin-3-yl]propanamide (compound E) is a gamma-secretase inhibitor capable of reducing amyloid beta-peptide (1-40) and amyloid beta-peptide (1-42) levels. In this study we investigated the effect of in vivo administration of compound E on guinea-pig plasma, CSF and cortical amyloid beta-peptide (1-40) concentration. Using repeated sampling of CSF, compound E (30 mg/kg p.o.) was shown to cause a time-dependent decrease in CSF amyloid beta-peptide (1-40) levels, which was maximal at 3 h (70% inhibition), compared to baseline controls. After 3 h administration, compound E (3, 10 and 30 mg/kg p.o.), reduced plasma, CSF and DEA-extracted cortical amyloid beta-peptide (1-40) levels by 95, 97 and 99%; 26, 48 and 78%; 32, 33, and 47%, respectively, compared to vehicle control values. In the same animals, compound E (3, 10 and 30 mg/kg p.o.) inhibited cortical gamma-secretase activity, determined ex vivo using the recombinant substrate C100Flag, by 40, 71 and 79% of controls, respectively. These data demonstrate the value of determining not only the extent by which systemic administration of a gamma-secretase inhibitor reduces amyloid beta-peptide, but also the inhibition of brain gamma-secretase activity, as a more direct estimate of enzyme occupancy.

Autocatalyst-derived platinum, palladium and rhodium (PGE) in infiltration basin and wetland sediments receiving urban runoff

The emission of platinum group elements (PGE) from automobile catalytic converters has led to rapid increases in Pt, Pd and Rh concentrations in roadside media. Significant quantities of the PGE may enter and accumulate in fluvial systems via road runoff. This paper examines the occurrence and spatial distribution of autocatalyst-derived PGE in surface sediments of infiltration basin and wetland sediments receiving road-runoff in Perth, Western Australia. Samples were analysed by ICP-MS following microwave digestion and cation exchange. PGE concentrations ranged between 1.5-17.2 Rh, 5.4-61.2 Pd and 9.0-103.8 ng g(-1) Pt. The highest levels of PGE were generally found at basin topographic low points and these concentrations were found to be strongly related to the area of road surface drained and the traffic volume. PGE ratios in infiltration basin and wetland sediments were within the typical range of catalytic converter compositions. However, comparisons of PGE ratios between parent road dusts and infiltration basin sediments revealed a systematic shift in Pt/Pd ratios, suggesting that PGE fractionation can occur during transport through the drainage system and that a small portion of Pd in road dust may be solubilised under natural conditions.

Hepatitis C among drug users: consensus guidelines on management in general practice

BACKGROUND

Hepatitis C (HCV) is a common cause of morbidity among patients who attend general practitioners (GPs) in Ireland for methadone maintenance treatment.

AIMS

To describe the development and content of guidelines for the management of HCV among current or former opiate users in the Eastern Regional Health Authority area attending GPs for methadone treatment.

METHODS

The guidelines were produced in five stages: identification of key stakeholders; development of evidence-based draft guidelines; discussion of content; determination of 'Delphi'-facilitated consensus and review by a sample of GPs for whom the guidelines would be intended.

RESULTS

The guidelines contain advice for GPs on all aspects of care of patients at risk of HCV, including general and preventative care, care of other bloodborne and hepatotoxic viruses, and the factors to be considered and appropriate evaluation prior to referring a patient for assessment at a hepatology unit.

CONCLUSIONS

GPs have an important role to play in the care of patients at risk of, or infected with, HCV.

Comparison of Agrobacterium-mediated transformation of four barley cultivars using the GFP and GUS reporter genes

Experiments were conducted to produce transgenic barley plants following infection of immature embryos with Agrobacterium tumefaciens. Transformed callus was obtained using hygromycin resistance as a selectable marker and either green fluorescent protein (GFP) or beta-glucuronidase (GUS) as a reporter. Significantly reduced plant transformation frequencies were obtained with the GFP gene compared to GUS. However, GFP proved to be an excellent reporter of early transformation events and was used to compare four barley cultivars for efficiency in two phases of transformation: the generation of stably transformed barley callus and the regeneration of plantlets from transformed callus. Transformed callus was generated at a high frequency (47-76%) in all four cultivars. Regeneration of transformed plantlets was also achieved for all four cultivars although the frequency was much higher for Golden Promise than for the other three genotypes, reiterating that genotype is an important determinant in the regenerative ability of barley. This study has demonstrated for the first time that Agrobacterium-mediated transformation can be used to transform the Australian cultivars Sloop and Chebec.

Anthropogenic platinum group element (Pt, Pd and Rh) concentrations in road dusts and roadside soils from Perth, Western Australia

The emission of platinum group elements (PGE) from automobile catalytic converters has led to rapid increases in Pt, Pd and Rh concentrations in roadside media. This article represents the first detailed study to assess PGE levels in road dusts and roadside soils in Australia. Road dust and roadside soil samples were analysed by ICP-MS following microwave digestion and cation exchange. All samples show elevation of PGE above average upper crust values, with maximum values of 420 ng g(-1) Pt, 440 ng g(-1) Pd and 91 ng g(-1) Rh. PGE ratios in road dusts and soils are consistent with known catalytic converter compositions and while Pt and Rh abundances are comparable with European studies, Pd levels are substantially higher in Australian samples. PGE in these samples are not correlated with Pb, though positive correlations with Ce, Cu and Y are evident. No straightforward relationship between traffic volume and PGE abundance is evident and factors such as driving style, topography, road drainage and potentially climate exert considerable influences.

Changes in airborne fungi from the outdoors to indoor air; large HVAC systems in nonproblem buildings in two different climates

Little is known about the changes in occurrence and distribution of airborne fungi as they are transported in the airstream from the outdoor air through the heating, ventilation, and air conditioning (HVAC) system to the indoor air. To better understand this, airborne fungi were analyzed in the HVAC systems of two large office buildings in different climate zones. Fungal samples were taken in each of the walk-in chambers of the HVAC systems using a six-stage Andersen Sampler with malt extract agar. Results showed that fungal species changed with different locations in the HVAC systems. The outdoor air intake produced the greatest filtration effect for both the counts and species of outdoor air fungi. The colony forming unit (CFU) counts and species diversity was further reduced in the air directly after the filters. The cooling coils also had a substantial filtration effect. However, in room air the CFU counts were double and the mixture of fungal species was different from the air leaving the HVAC system at the supply air outlet in most locations. Diffusion of outdoor air fungi to the indoors did not explain the changes in the mixture of airborne fungi from the outdoor air to the indoor air, and some of the fungi present in the indoor air did not appear to be transported indoors by the HVAC systems.

Esomeprazole 20 mg and lansoprazole 15 mg in maintaining healed reflux oesophagitis: Metropole study results

INTRODUCTION

Esomeprazole, the first proton pump inhibitor to be developed as an optical isomer, has demonstrated more effective healing vs. omeprazole and lansoprazole in patients with reflux oesophagitis (RO). However, RO recurs in a high proportion (approximately 80%) of these patients within 12 months of initial therapy, highlighting the importance of maintenance treatment. Previous studies have shown esomeprazole to be effective as maintenance therapy in healed RO patients.

AIM

This study was conducted to compare esomeprazole 20 mg once daily (o.d.) with lansoprazole 15 mg o.d. for the prevention of recurrence of RO.

METHODS

1391 patients with endoscopically verified RO (LA classification) were enrolled in this randomized, double-blind, parallel-group, multicentre trial. During the initial healing phase of the study, all patients received 4-8 weeks' open treatment with esomeprazole 40 mg: 1236 healed (identified by endoscopy at 4 and 8 weeks) and symptom-free (i.e. no heartburn or acid regurgitation) patients were randomized to 6 months' maintenance treatment with esomeprazole 20 mg o.d. or lansoprazole 15 mg o.d. Time to relapse (relapse of RO and/or discontinuation due to symptom recurrence) was analysed using a log-rank test.

RESULTS

Esomeprazole maintained a significantly higher proportion of patients in remission than lansoprazole over the 6-month course of treatment (P < 0.0001, intention-to-treat analysis). After 6 months' treatment, 83% of esomeprazole recipients were in remission compared with 74% of lansoprazole recipients (life-table estimates). Esomeprazole gave a longer time to relapse than lansoprazole irrespective of baseline LA Grade, significantly so for baseline LA Grades B, C and D (P < 0.05 for each comparison). Significantly more patients were free from heartburn in the esomeprazole group compared with the lansoprazole group at 1, 3 and 6 months (P < 0.05). Significant differences at 6 months between esomeprazole 20 mg o.d. and lansoprazole 15 mg o.d. were also observed for control of epigastric pain and acid regurgitation (P < 0.05 and P < 0.001, respectively). Both treatment regimens were well tolerated.

CONCLUSION

Esomeprazole 20 mg o.d. is a more effective maintenance treatment than lansoprazole 15 mg o.d. for symptom-free patients with healed RO.

Esomeprazole 20 mg and lansoprazole 15 mg in maintaining healed reflux oesophagitis: Metropole study results

AIM

To compare the efficacy of esomeprazole, 20 mg once daily, vs. lansoprazole, 15 mg once daily, for the maintenance treatment of patients with healed reflux oesophagitis.

METHODS

During the initial open healing phase, 1391 patients with endoscopically verified reflux oesophagitis and a history of heartburn, with or without acid regurgitation, received esomeprazole 40 mg for 4-8 weeks. Patients who were healed (identified by endoscopy at 4 or 8 weeks) and symptom free were then randomized to receive 6 months of treatment with esomeprazole, 20 mg once daily, or lansoprazole, 15 mg once daily.

RESULTS

Esomeprazole, 20 mg once daily, maintained a significantly higher proportion of patients in remission than lansoprazole, 15 mg once daily, over 6 months [83% (95% CI, 80-86%) of esomeprazole recipients compared with 74% (95% CI, 70-78%) of lansoprazole recipients; P < 0.0001; life table estimates]. When data were analysed according to baseline Los Angeles grade classification, esomeprazole, 20 mg once daily, achieved consistently higher remission rates across all grades of disease severity, whereas the efficacy of lansoprazole decreased to a greater extent with increasing severity of reflux oesophagitis.

CONCLUSION

Esomeprazole, 20 mg once daily, is more effective than lansoprazole, 15 mg once daily, in maintaining remission in patients with healed reflux oesophagitis.

Helicobacter Pylori eradication therapy: getting research into practice

Helicobacter Pylori (H. Pylori) is the primary cause of duodenal ulcer (DU). Guidelines recommend that all patients with DU be considered for Helicobacter Pylori Eradication Therapy (HPET). However, the proportion of patients with DU on long term anti-ulcer medication receiving HPET is small. This study examined the effectiveness of the continuing medical education (CME) network of the Irish College of General Practitioners (ICGP) in promoting best practice in DU treatment among GPs in an eastern region of Ireland. Ninty eight GPs recruited from the CME network of the ICGP were randomised in two cohorts. Cohort 1 received an (early) intervention; GPs were asked to identify their patients with DU receiving long term anti-ulcer medication and prescribe HPET according to defined criteria. Cohort 2 received the intervention later. Prescribing of HPET was monitored using routine prescribing data. Twenty per cent (286/1,422) of patients in cohort 1 and 19.2% (127/661) in cohort 2 had a DU. After exclusions, 53% (152/286) in cohort 1 and 30.7% (39/127) in cohort 2, were eligible for HPET. A significantly higher proportion of patients in cohort 1 received HPET compared with cohort 2 during the early intervention period (13.8% vs 0.0%, p<0.05). Reasons for not prescribing HPET included concurrent illness in patients, failure to comply with treatment. Best practice guidelines on HPET treatment of DU can be successfully applied using CME networks. This model could be repeated in another therapeutic area where established research is not yet current practice.

Physiological and metabolic characteristics of elite tug of war athletes

OBJECTIVE

To determine the aerobic power (VO(2)MAX), body composition, strength, muscular power, flexibility, and biochemical profile of an elite international squad of tug of war athletes.

METHODS

Sixteen male competitors (mean (SEM) age 34 (2) years) were evaluated in a laboratory. For comparative purposes, data were analysed relative to normative data for our centre and to a group of 20 rugby forwards from the Irish international squad.

RESULTS

The tug of war participants were lighter (83.6 (3.0) v 104.4 (1.8) kg, p<0.0001) and had less lean body mass (69.4 (2.1) v 86.2 (1.2) kg) than the rugby players and had lower than normal body fat (16.7 (0.9)%); all values are mean (SEM). Aerobic power measured during a treadmill test was 55.8 (1.6) ml/kg/min for the tug of war participants compared with 51.1 (1.4) ml/kg/min for the rugby forwards (p<0.03). A composite measure of strength derived from (sum of dominant and non-dominant grip strength and back strength)/lean body mass yielded a strength/mass ratio that was 32% greater (p<0.0001) for the tug of war group than the rugby group. Dynamic leg power was lower for the tug of war group than the rugby forwards (4659.8 (151.6) v 6198.2 (105) W respectively; p<0.0001). Leg flexibility was 25.4 (2.0) cm for the tug of war group. Back flexibility was 28.6 (1.4) cm which was lower (p<0.02) than the rugby forwards 34.2 (1.5) cm. Whereas blood chemistry and haematology were normal, packed cell volume, haemoglobin concentration, and erythrocyte volume were lower in the tug of war group than in the rugby players (p<0.05). All three haematological measures correlated with muscle mass (packed cell volume, r(2) = 0.37, p<0.0001; haemoglobin concentration, r(2) = 0.13, p<0.05; erythrocyte volume, r(2) = 0.21, p<0.01).

CONCLUSIONS

The data indicate that international level tug of war participants have excellent strength and above average endurance relative to body size, but have relatively low explosive leg power and back flexibility. The data provide reference standards for the sport and may be useful for monitoring and evaluating current and future participants.

Positive and negative contractile effects of somatostatin-14 on rat ventricular cardiomyocytes

Somatostatin-14 elicits negative inotropic and chronotropic actions in atrial myocardium. Less is known about the effects of somatostatin-14 in ventricular myocardium. The direct contractile effects of somatostatin-14 were assessed using ventricular cardiomyocytes isolated from the hearts of adult rats. Cells were stimulated at 0.5 Hz with CaCl2 (2 mM) under basal conditions and in the presence of the beta-adrenoceptor agonist, isoprenaline (1 nM), or the selective inhibitor of the transient outward current (Ito), 4-aminopyridine (500 microM). Somatostatin-14 did not alter basal contractile response but it did inhibit (IC50 = 13 nM) the response to isoprenaline (1 nM). In the presence of 4-aminopyridine (500 microM), somatostatin-14 stimulated a positive contractile response (EC50 = 118 fM) that was attenuated markedly by diltiazem (100 nM). These data indicate that somatostatin-14 exerts dual effects directly in rat ventricular cardiomyocytes: (1) a negative contractile effect, observed in the presence of isoprenaline (1 nM), coupled to activation of Ito; and (2) a previously unreported and very potent positive contractile effect, unmasked by 4-aminopyridine (500 microM), coupled to the influx of calcium ions via L-type calcium channels. The greater potency of somatostatin-14 for producing the positive contractile effect indicates that the peptide may exert a predominantly stimulatory influence on the resting contractility of ventricular myocardium in vivo, whereas the negative contractile effect, observed at much higher concentrations, could indicate that localized elevations in the concentration of the peptide may serve as a negative regulatory influence to limit the detrimental effects of excessive stimulation of cardiomyocyte contractility.

Characterisation of N-methyl-D-aspartate receptor-specific [(3)H]Ifenprodil binding to recombinant human NR1a/NR2B receptors compared with native receptors in rodent brain membranes

We have performed [(3)H]ifenprodil binding experiments under NMDA receptor-specific assay conditions to provide the first detailed characterisation of the pharmacology of the ifenprodil site on NMDA NR1/NR2B receptors, using recombinant human NR1a/NR2B receptors stably expressed in L(tk-) cells, in comparison with rat cortex/hippocampus membranes. [(3)H]Ifenprodil bound to a single, saturable site on both human recombinant NR1a/NR2B receptors and native rat receptors with B:(max) values of 1.83 and 2.45 pmol/mg of protein, respectively, and K:(D) values of 33.5 and 24.8 nM:, respectively. The affinity of various ifenprodil site ligands-eliprodil, (R:(*), R:(*))-4-hydroxy-alpha-(4-hydroxyphenyl)-beta-methyl-4-pehnyl-1-pi per idineethanol [(+/-)-CP-101,606], cis-3-[4-(4-fluorophenyl)-4-hydroxy-1-piperidinyl]-3, 4-dihydro-2H:-1-benzopyran-4,7-diol [(+/-)-CP-283,097], and (R:(*), S:(*))-alpha-(4-hydroxyphenyl)-beta-methyl-4-(phenylmethyl)-1-piperid inepropanol [(+/-)-Ro 25-6981] was very similar for inhibition of [(3)H]ifenprodil binding to recombinant human NR1a/NR2B and native rat receptors, whereas allosteric inhibition of [(3)H]ifenprodil binding by polyamine site ligands (spermine, spermidine, and arcaine) showed approximately twofold lower affinity for recombinant receptors compared with native receptors. Glutamate site ligands were less effective at modulating [(3)H]ifenprodil binding to recombinant NR1a/NR2B receptors compared with native rat receptors. The NMDA receptor-specific [(3)H]ifenprodil binding conditions described were also applied to ex vivo experiments to determine the receptor occupancy of ifenprodil site ligands [ifenprodil, (+/-)-CP-101,606, (+/-)-CP-283,097, and (+/-)-Ro 25-6981] given systemically.

Modulation of [3H]MK-801 binding to NMDA receptors in vivo and in vitro

[3H]MK-801 binding in vivo was used to determine the occupancy of NMDA receptor ligands shown to allosterically modulate binding in vitro. ED(50) values (mg/kg) were obtained for the channel blockers (+)-5-methyl-10,11-dihydro-5,4-dibenzo[a,d]cyclohepten-5,10-imine maleate ((+)-MK-801, 0.2), 1-(1-phenylcyclohexyl)piperidine (phencyclidine, PCP, 1.7) and ketamine (4.4). Antagonists at the glutamate (DL-(2-carboxypiperazine-4-yl)propyl-1-phosphonate (DL-CPP, 5.7)) and glycine site (7-Chloro-4-hydroxy-3-(3-phenoxy)-phenyl-2(H)quinolinone (L-701,324, 14.1), 3R(+)cis-4-methyl-pyrrollid-2-one (L-687,414, 15.1)) inhibited [3H]MK-801 binding in vivo to varying maximum levels (69%, 103% and 45%, respectively). NR2B subunit-selective compounds acting at the ifenprodil site inhibited [3H]MK-801 in vivo by a maximum of 52-72% and gave ED(50) values (mg/kg) of: (+/-)-(1S*, 2S*)-1-(4-hydroxyphenyl)-2-(4-hydroxy-4-phenylpiperidino)-1-propanol ((+/-)CP-101,606), 1.9; (+/-)-(3R, 4S)-3-[4-(4-fluorophenyl)-4-hydroxypiperidin-1-yl]chroman-4,7-diol ((+/-)CP-283,097), 1.8; (+/-)-(R*, S*)-alpha-(4-hydroxyphenyl)-beta-methyl-4-(phenylmethyl)-1-piperidine propanol ((+/-)Ro 25-6981), 1.0; ifenprodil, 6.0. The glycine site agonist D-serine stimulated binding to 151% of control with an ED(50) of 1.7 mg/kg. Results show that [3H]MK-801 binding in vivo may be used to measure receptor occupancy of ligands acting not only within the ion channel but also at modulatory sites on the NMDA receptor complex.

Management of peripheral intravenous therapy

Practice profiles are reflective pieces written by nurses in practice and based on continuing professional development articles. This week Frances Murray discusses peripheral intravenous therapy.

Evaluation of total volatile organic compound emissions from adhesives based on chamber tests

In 1997, Homeswest in western Australia and Murdoch University developed a project to construct low-allergen houses (LAHs) in a newly developed suburb. Before the construction of LAHs, all potential volatile organic compound (VOC) emission materials used in LAHs are required to be measured to ensure that they are low total VOC (TVOC) emission materials. This program was developed based on this purpose. In recent times, the number of complaints about indoor air pollution caused by VOCs has increased. A number of surveys of indoor VOCs have indicated that many indoor materials contribute to indoor air pollution. Although some studies have been conducted on the characteristics of VOC emissions from adhesives, most of them were focused on VOC emissions from floor adhesives. Few measurements of VOC emissions from adhesives used for wood, fabrics, and leather are available. Furthermore, most research on VOC emissions from adhesives has been done in countries with cool climates, where ventilation rates in the indoor environment are lower than those in Mediterranean climates, due to energy conservation. VOCs emitted from adhesives have not been sufficiently researched to prepare an emission inventory to predict indoor air quality and to determine both exposure levels for the Australian population and the most appropriate strategies to reduce exposure. An environmental test chamber with controlled temperature, relative humidity, and airflow rate was used to evaluate emissions of TVOCs from three adhesives used frequently in Australia. The quantity of TVOC emissions was measured by a gas chromatography/flame ionization detector. The primary VOCs emitted from each adhesive were detected by gas chromatography/mass spectrometry. The temporal change of TVOC concentrations emitted from each adhesive was tested. A double-exponential equation was then developed to evaluate the characteristics of TVOC emissions from these three adhesives. With this double-exponential model, the physical processes of TVOC emissions can be explained, and a variety of emission parameters can be calculated. These emission parameters could be used to estimate real indoor TVOC concentrations in Mediterranean climates.

Diabetic foot ulcer associated with Wegener's granulomatosis

A case report describing the use of conservative therapies to treat a dorso-plantar ulcer in a patient with diabetes complicated by Wegener's granulomatosis.

Novel selective compounds for the investigation of imidazoline receptors

Over several years our group has sought to synthesize and identify selective ligands for imidazoline (I) receptors, in particular the I2 binding site. As a consequence, [3H]2-(2-benzofuranyl)-2-imidazoline (2BFI) has proved extremely useful for binding and autoradiographic studies. More recently we have synthesized a BU series of compounds and examined these for their affinities for both I1 and I2 binding sites. BU224 (2-(4,5-dihydroimidaz-2-yl)-quinoline) shows high affinity for I2 receptors with a Ki of 2.1 nM. BU226 (2-(4,5-dihydroimidaz-2-yl)-isoquinoline) demonstrated slightly higher affinity (Ki 1.4 nM) for I2 receptors, but overall BU224 displayed greater selectivity for I2 over I1 receptors (832-fold) than BU226 (380-fold). Both compounds showed low (microM) affinity for alpha 2-adrenoceptors. Given BU224's ability to cross the blood brain barrier, we predict that its in vivo effects are likely to be mediated via I2 receptors. Brain dialysis revealed BU224 to dose dependently (0-20 mg/kg i.p.) elevate basal noradrenaline in rat frontal cortex and basal dopamine in striatum. In a rat model of opiate withdrawal, behavioral studies showed that BU224 (10 mg/kg, s.c.) was able to reduce acute weight loss and diarrhea, but not the number of wet dog shakes associated with the withdrawal syndrome.