Plastics in the global environment assessed through material flow analysis, degradation and environmental transportation

Knowledge on environmental plastic emission and spatial and temporal accumulation is vital for the development of successful mitigation strategies and risk assessments of plastics. In this study, emissions of both micro and macro plastic from the plastic value chain to the environment were assessed on a global level through a mass flow analysis (MFA). All countries, 10 sectors, 8 polymers and 7 environmental compartments (terrestrial, freshwater or oceanic) are distinguished in the model. The results assess a loss of 0.8 million tonnes (mt) of microplastics and 8.7 mt of macroplastics to the global environment in 2017. This is respectively 0.2 % and 2.1 % of plastics produced in the same year. The packaging sector contributed most for macroplastic emissions, and tyre wear for microplastic emissions. With the MFA results, accumulation, degradation and environmental transportation are considered in the Accumulation and dispersion model (ADM) until 2050. This model predicts macro- and microplastic accumulation in the environment to 2.2 gigatonnes (Gt) and 3.1 Gt in 2050 respectively (scenario: yearly consumption increase of 4 %). This will be 30 % less when a yearly production reduction of 1 % until 2050 is modeled to 1.5 and 2.3 Gt macro and microplastics respectively. Almost 2.15 Gt of micro and macroplastics accumulate in the environment until 2050 with zero plastic production after 2022 due to leakage from landfills and degradation processes. Results are compared to other modeling studies quantifying plastic emissions to the environment. The current study predicts lower emissions to ocean and higher emissions to surface waters like lakes and rivers. Non aquatic, terrestrial compartments are observed to accumulate most plastics emitted to the environment. The approach used results in a flexible and adaptable model that addresses plastic emissions to the environment over time and space, with detail on country level and environmental compartments.

Evaluation of clinicians' knowledge and practices regarding medical radiological exposure: findings from a mixed-methods investigation (survey and qualitative study)

OBJECTIVES

To assess the impact of initiatives aiming to increase clinician awareness of radiation exposure; to explore the challenges they face when communicating with patients; to study what they think is the most appropriate way of communicating the long-term potential risks of medical radiological exposure to patients.

DESIGN

A quantitative and qualitative evaluation through a survey and focal groups.

SETTING

San Juan Hospital and Dr Peset Hospital (Southeast Spain) and clinicians from Spanish scientific societies.

PARTICIPANTS

The surveys were answered (a) in person (216: all the radiologists (30), urologists (14) and surgeons (44) working at both participant hospitals; a sample of general practitioners from the catchment area of one hospital (45), and a consecutive sample of radiologists attending a scientific meeting (60)) or (b) electronically through Spanish scientific societies (299: radiologists (45), pneumologists (123), haematologists (75) and surgeons (40)). Clinicians were not randomly selected and thus the results are limited by the diligence of the individuals filling out the survey.

PRIMARY AND SECONDARY OUTCOME MEASURES

Clinicians' knowledge and practices regarding medical radiological exposure, and what they considered most appropriate for communicating information to patients.

RESULTS

Nearly 80% of the clinicians surveyed had never heard of the European recommendations. Fewer than 20% of the clinicians surveyed identified correctly the radiation equivalence dose of intravenous urography or barium enema. It was reported by 31.7% that they inform patients about the long-term potential risks of ionising radiation. All participants agreed that the most appropriate way to present information is a table with a list of imaging tests and their corresponding radiation equivalence dose in terms of chest X-rays and background radiation exposure.

CONCLUSIONS

Medical radiological exposure is frequently underestimated and rarely explained to patients. With a clear understanding of medical radiological exposure and proper communication tools, clinicians will be able to accurately inform patients.

Cannabinoids suppress acute and anticipatory nausea in preclinical rat models of conditioned gaping

The sensation of nausea is one of the most debilitating human experiences. Current antiemetic therapies are effective in reducing vomiting, but are less effective in reducing acute and delayed nausea and are completely ineffective in reducing anticipatory nausea. Recent preclinical evidence using a selective rat model of nausea (conditioned gaping reactions) has revealed that cannabinoids have great promise as treatments for nausea and that their antinausea effects may be mediated by the interoceptive insular cortex.

Intra-visceral insular cortex 2-arachidonoylglycerol, but not N-arachidonoylethanolamide, suppresses acute nausea-induced conditioned gaping in rats

The visceral insular cortex (VIC) has previously been shown to play a critical role during acute nausea-induced conditioned gaping in rats. Specifically, localized administration of the conventional anti-emetic, ondansetron or the synthetic cannabinoid, HU210, interferes with the establishment of conditioned gaping, likely by reducing the effects of an illness-inducing treatment. However the precise role of the VIC in endocannabinoid-suppression of nausea remains unknown; thus we investigated the potential of localized intra-VIC endocannabinoid administration to interfere with acute nausea-induced conditioned gaping behavior in male Sprague-Dawley rats. Animals received an intraoral infusion of saccharin (0.1%) followed by intra-VIC exogenous N-arachidonoylethanolamide (AEA; 0.4, 4 μg) or 2-arachidonoylglycerol (2-AG; 0.5, 1 μg), and were subsequently injected with nausea-inducing LiCl (0.15M) 15 min later. Bilateral intra-VIC infusions of 2-AG (1 μg, but not 0.5 μg) dose-dependently suppressed conditioned gaping, whereas exogenous AEA was without effect. Interestingly, 2-AG reduced conditioned gaping despite additional pretreatment with the selective cannabinoid receptor type 1 (CB1) antagonist, AM-251; however, concomitant pretreatment with the cyclooxygenase inhibitor, indomethacin (0.5 μg), blocked the suppressive effects of intra-VIC 2-AG. These findings suggest that the modulatory role of the endocannabinoid system during nausea is driven largely by the endocannabinoid, 2-AG, and that its anti-nausea effects may be partly independent of CB1-receptor signaling through metabolic products of the endocannabinoid system.

Effect of low doses of cannabidiolic acid and ondansetron on LiCl-induced conditioned gaping (a model of nausea-induced behaviour) in rats

BACKGROUND AND PURPOSE

To determine the minimally effective dose of cannabidiolic acid (CBDA) that effectively reduces lithium chloride (LiCl)-induced conditioned gaping reactions (nausea-induced behaviour) in rats and to determine if these low systemic doses of CBDA (5-0.1 μg·kg⁻¹) relative to those of CBD could potentiate the anti-nausea effects of the classic 5-hydroxytryptamine 3 (5-HT₃) receptor antagonist, ondansetron (OND).

EXPERIMENTAL APPROACH

We investigated the efficacy of low doses of CBDA to suppress acute nausea, assessed by the establishment of conditioned gaping to a LiCl-paired flavour in rats. The potential of threshold and subthreshold doses of CBDA to enhance the reduction of nausea-induced conditioned gaping by OND were then determined.

KEY RESULTS

CBDA (at doses as low as 0.5 μg·kg⁻¹) suppressed nausea-induced conditioned gaping to a flavour. A low dose of OND (1.0 μg·kg⁻¹) alone reduced nausea-induced conditioned gaping, but when it was combined with a subthreshold dose of CBDA (0.1 μg·kg⁻¹) there was an enhancement in the suppression of LiCl-induced conditioned gaping.

CONCLUSIONS AND IMPLICATIONS

CBDA potently reduced conditioned gaping in rats, even at low doses and enhanced the anti-nausea effect of a low dose of OND. These findings suggest that combining low doses of CBDA and OND will more effectively treat acute nausea in chemotherapy patients.

Tetrahydrocannabinolic acid reduces nausea-induced conditioned gaping in rats and vomiting in Suncus murinus

BACKGROUND AND PURPOSE

We evaluated the anti-emetic and anti-nausea properties of the acid precursor of Δ(9) -tetrahydrocannabinol (THC), tetrahydrocannabinolic acid (THCA), and determined its mechanism of action in these animal models.

EXPERIMENTAL APPROACH

We investigated the effect of THCA on lithium chloride- (LiCl) induced conditioned gaping (nausea-induced behaviour) to a flavour, and context (a model of anticipatory nausea) in rats, and on LiCl-induced vomiting in Suncus murinus. Furthermore, we investigated THCA's ability to induce hypothermia and suppress locomotion [rodent tasks to assess cannabinoid1 (CB1 ) receptor agonist-like activity], and measured plasma and brain THCA and THC levels. We also determined whether THCA's effect could be blocked by pretreatment with SR141716 (SR, a CB1 receptor antagonist).

KEY RESULTS

In rats, THCA (0.05 and/or 0.5 mg·kg(-1) ) suppressed LiCl-induced conditioned gaping to a flavour and context; the latter effect blocked by the CB1 receptor antagonist, SR, but not by the 5-hydroxytryptamine-1A receptor antagonist, WAY100635. In S. murinus, THCA (0.05 and 0.5 mg·kg(-1) ) reduced LiCl-induced vomiting, an effect that was reversed with SR. A comparatively low dose of THC (0.05 mg·kg(-1) ) did not suppress conditioned gaping to a LiCl-paired flavour or context. THCA did not induce hypothermia or reduce locomotion, indicating non-CB1 agonist-like effects. THCA, but not THC was detected in plasma samples.

CONCLUSIONS AND IMPLICATIONS

THCA potently reduced conditioned gaping in rats and vomiting in S. murinus, effects that were blocked by SR. These data suggest that THCA may be a more potent alternative to THC in the treatment of nausea and vomiting.

Prevalence and variables associated with solitary pulmonary nodules in a routine clinic-based population: a cross-sectional study

Objective

To determine the prevalence of solitary pulmonary nodules (SPNs) in chest radiology studies and patient’s features associated with malignancy in a non-high-risk clinical population.

Methods

Patients ≥35 years were referred for thoracic imaging in two hospitals (2010-2011). Eight radiologists determined the presence and characteristics of SPN. Selected variables were collected from radiological register and medical records. Observer agreement in the diagnosis of SPN was assessed.

Results

25,529 patients were included: 23,102 (90.5 %) underwent chest radiograph and 2,497 (9.5 %) a CT. The prevalence of SPN was 2.1 % (95 % CI 1.9 – 2.3) in radiographs and 17.0 % (95 % CI 15.5 – 18.5) in CT. In patients undergoing chest radiograph, detection of SPN with an irregular border was more frequent among smokers. In patients who had a CT, larger SPNs appeared to be associated with 60 years of age or over, diagnosis of a respiratory illness, or male gender. In addition, an irregular border was also more common among men.

Conclusions

The prevalence of SPNs detected by both radiograph and CT was lower than that shown in screening studies. Patient characteristics such as age, sex, respiratory disease, or smoking habit were associated with nodule characteristics that are known to be related with malignancy.

Key Points

• There is a lower SPN prevalence in the clinical population than in screening studies.

• SPN prevalence is associated with some patient characteristics: sex, age, imaging test.

• Nodule characteristics related to malignancy were associated with some patient characteristics.

Anandamide transport inhibition by ARN272 attenuates nausea-induced behaviour in rats, and vomiting in shrews (Suncus murinus)

BACKGROUND AND PURPOSE

To understand how anandamide transport inhibition impacts the regulation of nausea and vomiting and the receptor level mechanism of action involved. In light of recent characterization of an anandamide transporter, fatty acid amide hydrolase-1-like anandamide transporter, to provide behavioural support for anandamide cellular reuptake as a facilitated transport process.

EXPERIMENTAL APPROACH

The systemic administration of the anandamide transport inhibitor ARN272 ([(4-(5-(4-hydroxy-phenyl)-3,4-diaza-bicyclo[4.4.0]deca-1(6),2,4,7,9-pentaen-2-ylamino)-phenyl)-phenylamino-methanone]) was used to evaluate the prevention of LiCl-induced nausea-induced behaviour (conditioned gaping) in rats, and LiCl-induced emesis in shrews (Suncus murinus). The mechanism of how prolonging anandamide availability acts to regulate nausea in rats was explored by the antagonism of cannabinoid 1 (CB1) receptors with the systemic co-administration of SR141716.

KEY RESULTS

The systemic administration of ARN272 produced a dose-dependent suppression of nausea-induced conditioned gaping in rats, and produced a dose-dependent reduction of vomiting in shrews. The systemic co-administration of SR141716 with ARN272 (at 3.0 mg·kg(-1)) in rats produced a complete reversal of ARN272-suppressed gaping at 1.0 mg·kg(-1). SR141716 alone did not differ from the vehicle solution.

CONCLUSIONS AND IMPLICATIONS

These results suggest that anandamide transport inhibition by the compound ARN272 tonically activates CB1 receptors and as such produces a type of indirect agonism to regulate toxin-induced nausea and vomiting. The results also provide behavioural evidence in support of a facilitated transport mechanism used in the cellular reuptake of anandamide.

Cannabidiolic acid prevents vomiting in Suncus murinus and nausea-induced behaviour in rats by enhancing 5-HT1A receptor activation

BACKGROUND AND PURPOSE

To evaluate the ability of cannabidiolic acid (CBDA) to reduce nausea and vomiting and enhance 5-HT(1A) receptor activation in animal models.

EXPERIMENTAL APPROACH

We investigated the effect of CBDA on (i) lithium chloride (LiCl)-induced conditioned gaping to a flavour (nausea-induced behaviour) or a context (model of anticipatory nausea) in rats; (ii) saccharin palatability in rats; (iii) motion-, LiCl- or cisplatin-induced vomiting in house musk shrews (Suncus murinus); and (iv) rat brainstem 5-HT(1A) receptor activation by 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and mouse whole brain CB(1) receptor activation by CP55940, using [³⁵S]GTPγS-binding assays.

KEY RESULTS

In shrews, CBDA (0.1 and/or 0.5 mg·kg⁻¹ i.p.) reduced toxin- and motion-induced vomiting, and increased the onset latency of the first motion-induced emetic episode. In rats, CBDA (0.01 and 0.1 mg·kg⁻¹ i.p.) suppressed LiCl- and context-induced conditioned gaping, effects that were blocked by the 5-HT(1A) receptor antagonist, WAY100635 (0.1 mg·kg⁻¹ i.p.), and, at 0.01 mg·kg⁻¹ i.p., enhanced saccharin palatability. CBDA-induced suppression of LiCl-induced conditioned gaping was unaffected by the CB₁ receptor antagonist, SR141716A (1 mg·kg⁻¹ i.p.). In vitro, CBDA (0.1-100 nM) increased the E(max) of 8-OH-DPAT.

CONCLUSIONS AND IMPLICATIONS

Compared with cannabidiol, CBDA displays significantly greater potency at inhibiting vomiting in shrews and nausea in rats, and at enhancing 5-HT(1A) receptor activation, an action that accounts for its ability to attenuate conditioned gaping in rats. Consequently, CBDA shows promise as a treatment for nausea and vomiting, including anticipatory nausea for which no specific therapy is currently available.

2-arachidonoylglycerol interferes with lithium-induced vomiting in the house musk shrew, Suncus murinus

The role of the endocannabinoid system in vomiting has been previously studied using several animal species. These investigations have clearly demonstrated an anti-emetic role for the eCB, anandamide, in these animal models; however, research concerning the role of 2-arhachidonoylglycerol (2AG) has been less clear. The aim of the present study was to assess the effects of exogenous 2AG administration in the house musk shrew, Suncus murinus. In Experiment 1, shrews were injected with vehicle or 2AG (1, 2, 5, 10 mg/kg) 15 min prior to behavioral testing in which the frequency of vomiting episodes was observed. In Experiment 2, shrews were pre-treated with 2AG (2, 5 mg/kg) prior to being administered the emetic drug, lithium chloride (LiCl). It was found that 2AG alone did not induce emesis, but interfered with vomiting in response to LiCl administration. The anti-emetic effects of 2AG in Suncus murinus do not appear to be mediated by CB1 receptors, as concomitant pretreatment with the CB1 receptor antagonist, SR141716, did not reverse the suppressive effects of 2AG. These results confirm that manipulations that increase levels of 2AG exert anti-emetic effects in the house musk shrew.

The anti-nausea effects of CB1 agonists are mediated by an action at the visceral insular cortex

BACKGROUND AND PURPOSE

Conditioned gaping reactions reflect nausea-induced behaviour in rats. Cannabinoid 1 receptor (CB(1) ) agonists interfere with the establishment of nausea-induced conditioned gaping; however, it is not known if their effects are mediated by an action at peripheral or central CB(1) receptors.

EXPERIMENTAL APPROACH

We utilized the conditioned gaping model of nausea to evaluate the effect of peripheral and central administration of the peripherally restricted CB(1) agonist, CB13, on the establishment of LiCl-induced gaping in rats. We further evaluated the ability of HU-210 administered to the gustatory insular cortex (GIC) or visceral insular cortex (VIC) to interfere with LiCl-induced conditioned gaping and determined if this effect was mediated by CB(1) receptors.

KEY RESULTS

Central, but not peripheral, CB13 suppressed LiCl-induced conditioned gaping. Central administration of the potent CB(1) agonist, HU-210, delivered to the VIC, but not the GIC, suppressed the establishment of LiCl-induced gaping reactions, but not LiCl-induced suppression of hedonic reactions or conditioned taste avoidance. This pattern of results suggests that HU-210 delivered to the VIC prevented LiCl-induced nausea, but not learning per se. The suppression of LiCl-induced conditioned gaping by HU-210 was mediated by CB(1) receptors because it was prevented by co-administration of CB(1) antagonist/inverse agonist, AM-251, into the VIC. A high dose of AM-251 (20 µg) administered alone into the VIC did not produce conditioned gaping reactions.

CONCLUSIONS AND IMPLICATIONS

The nausea-relieving effects of CB(1) agonists, but not the nausea-inducing effects of CB(1) inverse agonists, are mediated, at least in part, by their action at the VIC in rats.

Cannabidiol, a non-psychotropic component of cannabis, attenuates vomiting and nausea-like behaviour via indirect agonism of 5-HT(1A) somatodendritic autoreceptors in the dorsal raphe nucleus

BACKGROUND AND PURPOSE

To evaluate the hypothesis that activation of somatodendritic 5-HT(1A) autoreceptors in the dorsal raphe nucleus (DRN) produces the anti-emetic/anti-nausea effects of cannabidiol (CBD), a primary non-psychoactive cannabinoid found in cannabis.

EXPERIMENTAL APPROACH

The potential of systemic and intra-DRN administration of 5-HT(1A) receptor antagonists, WAY100135 or WAY100635, to prevent the anti-emetic effect of CBD in shrews (Suncus murinus) and the anti-nausea-like effects of CBD (conditioned gaping) in rats were evaluated. Also, the ability of intra-DRN administration of CBD to produce anti-nausea-like effects (and reversal by systemic WAY100635) was assessed. In vitro studies evaluated the potential of CBD to directly target 5-HT(1A) receptors and to modify the ability of the 5-HT(1A) agonist, 8-OH-DPAT, to stimulate [(35) S]GTPγS binding in rat brainstem membranes.

KEY RESULTS

CBD suppressed nicotine-, lithium chloride (LiCl)- and cisplatin (20 mg·kg(-1) , but not 40 mg·kg(-1) )-induced vomiting in the S. murinus and LiCl-induced conditioned gaping in rats. Anti-emetic and anti-nausea-like effects of CBD were suppressed by WAY100135 and the latter by WAY100635. When administered to the DRN: (i) WAY100635 reversed anti-nausea-like effects of systemic CBD, and (ii) CBD suppressed nausea-like effects, an effect that was reversed by systemic WAY100635. CBD also displayed significant potency (in a bell-shaped dose-response curve) at enhancing the ability of 8-OH-DPAT to stimulate [(35) S]GTPγS binding to rat brainstem membranes in vitro. Systemically administered CBD and 8-OH-DPAT synergistically suppressed LiCl-induced conditioned gaping.

CONCLUSIONS AND IMPLICATIONS

These results suggest that CBD produced its anti-emetic/anti-nausea effects by indirect activation of the somatodendritic 5-HT(1A) autoreceptors in the DRN.

LINKED ARTICLES

This article is part of a themed section on Cannabinoids in Biology and Medicine. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.165.issue-8. To view Part I of Cannabinoids in Biology and Medicine visit http://dx.doi.org/10.1111/bph.2011.163.issue-7.

GEBR-7b, a novel PDE4D selective inhibitor that improves memory in rodents at non-emetic doses

BACKGROUND AND PURPOSE

Strategies designed to enhance cerebral cAMP have been proposed as symptomatic treatments to counteract cognitive deficits. However, pharmacological therapies aimed at reducing PDE4, the main class of cAMP catabolizing enzymes in the brain, produce severe emetic side effects. We have recently synthesized a 3-cyclopentyloxy-4-methoxybenzaldehyde derivative, structurally related to rolipram, and endowed with selective PDE4D inhibitory activity. The aim of the present study was to investigate the effect of the new drug, namely GEBR-7b, on memory performance, nausea, hippocampal cAMP and amyloid-β (Aβ) levels.

EXPERIMENTAL APPROACH

To measure memory performance, we performed object recognition tests on rats and mice treated with GEBR-7b or rolipram. The emetic potential of the drug, again compared with rolipram, was evaluated in rats using the taste reactivity test and in mice using the xylazine/ketamine anaesthesia test. Extracellular hippocampal cAMP was evaluated by intracerebral microdialysis in freely moving rats. Levels of soluble Aβ peptides were measured in hippocampal tissues and cultured N2a cells by elisa.

KEY RESULTS

GEBR-7b increased hippocampal cAMP, did not influence Aβ levels and improved spatial, as well as object memory performance in the object recognition tests. The effect of GEBR-7b on memory was 3 to 10 times more potent than that of rolipram, and its effective doses had no effect on surrogate measures of emesis in rodents.

CONCLUSION AND IMPLICATIONS

Our results demonstrate that GEBR-7b enhances memory functions at doses that do not cause emesis-like behaviour in rodents, thus offering a promising pharmacological perspective for the treatment of memory impairment.

A novel peripherally restricted cannabinoid receptor antagonist, AM6545, reduces food intake and body weight, but does not cause malaise, in rodents

BACKGROUND AND PURPOSE

Cannabinoid CB(1) receptor antagonists reduce food intake and body weight, but clinical use in humans is limited by effects on the CNS. We have evaluated a novel cannabinoid antagonist (AM6545) designed to have limited CNS penetration, to see if it would inhibit food intake in rodents, without aversive effects.

EXPERIMENTAL APPROACH

Cannabinoid receptor binding studies, cAMP assays, brain penetration studies and gastrointestinal motility studies were carried out to assess the activity profile of AM6545. The potential for AM6545 to induce malaise in rats and the actions of AM6545 on food intake and body weight were also investigated.

KEY RESULTS

AM6545 binds to CB(1) receptors with a K(i) of 1.7 nM and CB(2) receptors with a K(i) of 523 nM. AM6545 is a neutral antagonist, having no effect on cAMP levels in transfected cells and was less centrally penetrant than AM4113, a comparable CB(1) receptor antagonist. AM6545 reversed the effects of WIN55212-2 in an assay of colonic motility. In contrast to AM251, AM6545 did not produce conditioned gaping or conditioned taste avoidance in rats. In rats and mice, AM6545 dose-dependently reduced food intake and induced a sustained reduction in body weight. The effect on food intake was maintained in rats with a complete subdiaphragmatic vagotomy. AM6545 inhibited food intake in CB(1) receptor gene-deficient mice, but not in CB(1)/CB(2) receptor double knockout mice.

CONCLUSIONS AND IMPLICATIONS

Peripherally active, cannabinoid receptor antagonists with limited brain penetration may be useful agents for the treatment of obesity and its complications.

Inverse agonism of cannabinoid CB1 receptors potentiates LiCl-induced nausea in the conditioned gaping model in rats

BACKGROUND AND PURPOSE

Cannabinoid CB(1) receptor antagonists/inverse agonists, potentiate toxin-induced nausea and vomiting in animal models. Here, we sought to determine if this potentiated nausea was mediated by inverse agonism or neutral antagonism of the CB(1) receptor, and if the potentiated nausea would be produced by intracerebroventricular (icv) administration of an inverse agonist.

EXPERIMENTAL APPROACH

The conditioned gaping model of nausea in rats was used to compare the CB(1) receptor antagonist/inverse agonist, AM251, and the CB(1) receptor neutral antagonists, AM6527 (centrally and peripherally active) and AM6545 (peripherally active), in potentiating conditioned gaping produced by lithium chloride (LiCl) solution. The effect of icv (lateral ventricle and 4th ventricle) administration of AM251 on LiCl-induced gaping in this model was also evaluated.

KEY RESULTS

At a dose that did not produce conditioned gaping on its own, systemically administered AM251 (1.25 mg.kg(-1)) potentiated LiCl-induced conditioned gaping and reduced sucrose palatability; however, even doses as high as 8 mg.kg(-1) of AM6545 and AM6527 neither potentiated LiCl-induced conditioned gaping nor reduced sucrose palatability. Infusions of AM251 into the lateral ventricles (1.25, 12.5 and 125 microg) or the 4th ventricle (2.5, 12.5 and 125 microg) did not potentiate LiCl-induced conditioned gaping reactions, but all doses attenuated saccharin palatability during the subsequent test.

CONCLUSIONS AND IMPLICATIONS

Inverse agonism, but not neutral antagonism, of CB(1) receptors potentiated toxin-induced nausea. This effect may be peripherally mediated or may be mediated centrally by action on CB(1) receptors, located distal to the cerebral ventricles.

The FAAH inhibitor URB-597 interferes with cisplatin- and nicotine-induced vomiting in the Suncus murinus (house musk shrew)

Considerable evidence implicates the endocannabinoid system as a neuromodulator of nausea and vomiting. The action of anandamide (AEA) can be prolonged by inhibiting its degradation, through the use of URB597 (URB), a Fatty Acid Amide Hydrolase (FAAH) enzyme inhibitor. Here we present evidence that the FAAH inhibitor, URB, interferes with cisplatin- and nicotine-induced vomiting in the Suncus murinus. In Experiment 1, shrews were injected with URB (0.9 mg/kg) or vehicle 120 min prior to the behavioral testing. They received a second injection of AEA (5 mg/kg) or vehicle 15 min prior to being injected with cisplatin (20 mg/kg) or saline and the number of vomiting episodes were counted for 60 min. In Experiment 2, shrews were injected with vehicle or URB (0.9 mg/kg) 120 min prior to receiving an injection of nicotine (5 mg/kg) or saline and the number of vomiting episodes were counted for 15 min. Experiment 3 evaluated the potential of the CB(1) antagonist, SR141716, to reverse the effect of URB on nicotine-induced vomiting. URB attenuated vomiting produced by cisplatin and nicotine and the combination of URB+AEA suppressed vomiting produced by cisplatin. The effect of URB on nicotine-induced vomiting was reversed by SR141716. These data suggest that the EC system plays a tonic role in the regulation of toxin-induced vomiting.

Predictive model for mediastinal lymph node status at the time of mediastinoscopy

18004

Background: Mediastinal lymph node (N2) positivity in non-small cell lung cancer (NSCLC) patients is suspected based on imaging such as CT or PET scan, with confirmation by mediastinoscopy. However, the most accurate clinical information in predicting N2 status is controversial. Methods: We reviewed 147 candidates for NSCLC resection (2000–2005) who had clinical database information available and had undergone mediastinoscopy. Using suspected clinical predictors of mediastinal metastasis available prior to mediastinoscopy, we constructed a predictive model of N2 status. Results: The largest N2 node short-axis diameter on CT was by far the most influential factor in the model. Three other predictors for N2 node positivity were significant (p<0.05) in univariate analysis: indistinct tumor borders and mediastinal invasion on CT, and mediastinal PET scan positivity. However, all were less influential than N2 size on CT. Using logistic regression, these factors can be used to predict probability of positive N2 biopsy in an individual patient. The resulting diagnostic test had a ROC (receiver operator characteristic) area of 0.80 and optimal sensitivity-specificity pairing of 75% and 73%. 35% (51/147) of patients analyzed had at least one N2 node positive at mediastinoscopy. 39% (57/147) of patients had PET scan data available, and 82% (120/147) had CT data available. Conclusions: Of available data in early-stage NSCLC patients, mediastinal lymph node size on CT scan was more important than PET scan or other CT scan findings in predicting probability of positive mediastinoscopy. A predictive model is useful in more accurately determining need for invasive staging by mediastinoscopy.

No significant financial relationships to disclose.

The cannabinoid CB1 antagonist AM 251 produces food avoidance and behaviors associated with nausea but does not impair feeding efficiency in rats

RATIONALE

A growing body of evidence suggests that cannabinoid CB1 receptor antagonists have potential therapeutic utility as appetite suppressants. However, the specific mechanisms underlying the reduction in food intake produced by these drugs are not well understood.

OBJECTIVE

Considering the known antiemetic and motor-suppressive effects of CB1 agonists, the present studies were conducted to determine if the reductions in food intake induced by the CB1 antagonist AM 251 could result from nausea or impairments in intake-related motor control, rather than solely from appetite suppression.

METHODS

Three experiments were conducted to examine the effects of AM 251 (2.0, 4.0, or 8.0 mg/kg or vehicle) on detailed parameters of food intake, on the development of conditioned taste avoidance, and on taste reactivity.

RESULTS

In the first experiment, acute administration of AM 251 dose-dependently decreased food intake; nevertheless, feeding rate (grams consumed per time spent eating) and food handling were unaffected, which suggests that food intake was not reduced because of severe motor impairments. In the second experiment, AM 251 dose-dependently reduced intake of a flavor with which it had previously been associated, indicating that conditioned taste avoidance had developed. Lastly, AM 251 was found to induce conditioned rejection reactions in a dose-dependent manner.

CONCLUSIONS

The CB1 antagonist AM 251 may reduce food intake in part by inducing nausea or malaise, but not because of incoordination or motor slowing related to feeding.

Intrapleural Tissue Plasminogen Activator for Complicated Pleural Effusions

BACKGROUND

This study is aimed at evaluating the safety and efficacy of intrapleural tissue plasminogen activator (TPA) for complicated pleural effusions, including posttraumatic hemothorax.

METHODS

Data were retrospectively collected from hospitalized patients over a 4-year period (1999-2003) who were treated with intrapleural TPA after failing drainage by tube thoracostomy. Pre- and post-TPA imaging studies were reviewed and scored by a blinded radiologist.

RESULTS

Forty-one consecutive patients with 42 effusions were identified with the following indications: 6 traumatic hemothoraces (14%), 22 loculated pleural effusions (52%), 2 line-associated hemothoraces (5%), and 12 empyemas (29%). Nine patients (22%) required operative drainage including two with posttraumatic hemothoraces. All patients managed nonoperatively demonstrated radiographic improvement after TPA administration. One patient (2.4%) developed hematuria, requiring transfusion. No trauma patient required TPA-related blood transfusion and no deaths were attributable to TPA therapy.

CONCLUSION

Intrapleural TPA administration appears safe for use in complicated pleural effusions and may decrease the need for operative intervention.

The dopamine antagonist, alpha-flupenthixol, interferes with naloxone-induced place aversion learning, but not with acute opiate dependence in rats

Pretreatment with the dopamine antagonist alpha-flupenthixol (alpha-flu) interfered with the establishment of a naloxone-induced place aversion in two experiments. In Experiment 1, the potential of pretreatment with alpha-flu to interfere with the establishment of a naloxone-induced place aversion was evaluated in rats administered morphine (Group MN) or saline (Group SN) 24 h prior to the naloxone conditioning trial. Naloxone-precipitated withdrawal from morphine administered 24 h prior to the trial produced a stronger place aversion than produced by naloxone alone. The neuroleptic, alpha-flu, attenuated the naloxone-induced place aversion, but did not selectively interfere with the place aversion produced by acute opiate dependence. Experiment 2 replicated demonstration of interference with naloxone-place aversion learning by neuroleptic pretreatment with the inclusion of saline controls. These results suggest that dopamine modulates either the aversive motivational properties of naloxone or learning, even in opiate naïve rats.

Frequency and CT findings of recurrent disease after lung transplantation

PURPOSE

To determine the frequency and computed tomographic (CT) findings of recurrence of the primary disease after lung transplantation at six North American lung transplantation centers.

MATERIALS AND METHODS

Medical records of 1,394 lung transplant recipients were reviewed to identify patients with recurrent primary disease. Their CT scans and pathologic specimens were reviewed.

RESULTS

The frequency of disease recurrence in the six transplantation centers was 1% (15 of 1,394 patients), including six previously reported cases. Sarcoidosis recurred in nine (35%) of 26 transplants and was the most common disease to recur. Three (33%) of nine patients with recurrent sarcoidosis had correlative findings at CT. When present, CT findings were usually different at recurrence compared with pretransplantation CT findings.

CONCLUSION

A relatively small percentage of patients are at risk for recurrence of primary disease following lung transplantation. Sarcoidosis is the most common disease to recur.

Tetrahydrocannabinol (THC) interferes with conditioned retching in Suncus murinus: an animal model of anticipatory nausea and vomiting (ANV)

Little is understood about effective countermeasures to the expression of anticipatory nausea and vomiting (ANV) in chemotherapy patients. We present a model of ANV based on the emetic reactions of the Suncus murinus (musk shrew). Following two pairings of a novel distinctive contextual cue with the emetic effects of an injection of lithium chloride, the context acquired the potential to elicit retching in the absence of the toxin. The expression of this conditioned retching reaction was completely suppressed by pretreatment with THC at a dose that did not suppress general activity. This provides the first experimental evidence in support of anecdotal reports that THC suppresses ANV.

The antiemetic drug ondansetron interferes with lithium-induced conditioned rejection reactions, but not lithium-induced taste avoidance in rats

Conditioned rejection reactions displayed in the taste reactivity test are exclusively produced by treatments that elicit nausea. The present experiments demonstrate that pretreatment with the antinausea agent ondansetron interferes with both the establishment and the expression of conditioned rejection reactions. Ondansetron did not interfere with lithium-induced taste avoidance in either a 1-bottle or a 2-bottle test. In fact, when rejection reactions were measured during a consumption test, ondansetron selectively attenuated rejection reactions, with only a slight modification of consumption. These results suggest that conditioned rejection reactions, but not conditioned taste avoidance, reflect nausea in rats that can be attenuated by ondansetron pretreatment.

Reinstatement of both a conditioned place preference and a conditioned place aversion with drug primes

In two experiments, we report that the place-conditioning paradigm can be used to demonstrate reinstatement of place preference/aversion by a drug prime following extinction training. In Experiment 1, rats were trained to prefer a chamber paired with morphine. Following extinction training, a morphine drug prime reinstated the morphine place preference. In Experiment 2, a lithium-induced conditioned place aversion was reinstated following extinction training by a lithium prime prior to testing. These results indicate that not only do rewarding drug primes produce reinstatement of learned responses (as demonstrated in the drug self-administration paradigm), but also aversive drug primes reinstate aversive learned responses.

Delta-9-tetrahydrocannabinol interferes with the establishment and the expression of conditioned rejection reactions produced by cyclophosphamide: a rat model of nausea

Reliable animal models of nausea are necessary to better understand the neurobiology of nausea and to assess treatment effectiveness. We present such a model based on conditioned rejection reactions in rats. Our results demonstrate that delta-9-tetrahydrocannabinol (THC), a treatment reported to reduce chemotherapy-induced nausea in humans, also reduces conditioned rejection reactions in rats. Rats were administered THC or vehicle prior to a pairing of saccharin solution with cyclophosphamide or saline during conditioning and/or prior to test. THC interfered with the establishment of cyclophosphamide-induced conditioned rejection during conditioning and with the expression of conditioned rejection during testing. Our results confirm that the conditioned rejection reaction in the rat is a useful animal model of nausea.

State of the art. Neonatal respiratory failure

Advances in ventilatory management of respiratory distress in the newborn have made dramatic strides during the last decade. Innovative treatments such as PTV, HFV, liquid ventilation, and NO therapy are just beginning to have an impact on the care of neonates in the NICU. These treatment modalities should continue to have an effect on the care of the newborn infant well into the future.

Rotation-induced conditioned rejection in the taste reactivity test

The taste reactivity test was used to evaluate the ability of motion sickness to produce conditioned rejection reactions, a putative measure of nausea in rats. Following three conditioning trials, rats displayed conditioned rejection reactions during an intraoral infusion of a rotation-paired saccharin solution. This is the first demonstration of conditioned rejection produced with a non-pharmacological emetic agent and provides support that the conditioned rejection reaction may serve as a rat model of nausea.

Inadequacy of computed tomography in assessing patients with esophageal carcinoma after induction chemoradiotherapy

BACKGROUND

Induction chemoradiotherapy followed by surgery may improve survival of patients with esophageal carcinoma. Computed tomography (CT) has been used to evaluate the tumor response after completing induction chemoradiotherapy. The authors examined the ability of CT to evaluate the pathologic tumor response to induction therapy and to stage the tumor correctly.

METHODS

Preinduction and postinduction chemoradiotherapy CT scans were reviewed retrospectively for 50 patients enrolled in a protocol of induction chemoradiotherapy followed by surgery. All studies were performed on third-generation or fourth-generation scanners. Radiographic response was determined using Eastern Cooperative Oncology Group solid tumor response criteria for bidimensional measurable disease. This was compared with the pathologic tumor response. CT-tumor (T) classification using the modified Tio scale was compared with the pathologic T classification.

RESULTS

CT-T classification did not correlate with the pathologic stage (P = 0.09) or the pathologic tumor response (P = 0.22). The postinduction chemoradiotherapy CT accurately staged the T classification in 42% of patients but overstaged 36% of patients and understaged 20% of patients. CT had a sensitivity of 65%, a specificity of 33%, a positive predictive value of 58%, and a negative predictive value of 41% in evaluating the pathologic tumor response.

CONCLUSIONS

CT is a poor diagnostic study tool for determining the pathologic tumor response or the pathologic disease stage after induction chemoradiotherapy in patients with esophageal carcinoma.

Naloxone-precipitated morphine withdrawal induced place aversions: effect of naloxone at 24 hours postmorphine

The aversive properties of naloxone-precipitated withdrawal from acutely administered morphine were assessed using the place-conditioning paradigm. The conditioned place aversion produced by naloxone (0.5-1.0 mg/kg, s.c.) after two conditioning trials was enhanced by pretreatment with morphine (20 mg/kg, s.c.) 24 h prior to the conditioning trial. Naloxone precipitated withdrawal from acutely administered morphine produces an aversive motivational state that becomes associated with place cues.

Ambiguous genitalia: etiology, treatment, and nursing implications

The infant presenting with ambiguous genitalia is a challenge to both the medical and nursing staff. The birth of any infant with ambiguous genitalia is considered a physical and psychologic emergency requiring prompt recognition and treatment for a positive outcome. A review of the etiology, presentation, diagnosis, and treatment of ambiguous genitalia is presented. The important aspects of family care also are discussed.

Chlordiazepoxide-induced conditioned place and taste aversion learning in rats

The hedonic properties of chlordiazepoxide (CDP) were examined using the place conditioning and the taste conditioning paradigms. Following four conditioning trials, CDP (5-20 mg/kg) produced a conditioned place aversion in an "unbiased" paradigm in which the chamber paired with CDP was counterbalanced among two equally preferred chambers. In a "biased" place-conditioning paradigm, CDP (5 and 20 mg/ kg) prevented the dissipation of the natural aversion to the nonpreferred chamber. Finally, although CDP unconditionally potentiated sucrose consumption, it produced a sucrose aversion in the taste reactivity test and sucrose avoidance in the taste avoidance test when the taste conditionally preceded injections of CDP. The pattern of findings suggest that, when novel to rats, CDP is hedonically aversive.

Conditioned sucrose aversions produced by naloxone-precipitated withdrawal from acutely administered morphine

The aversive properties of acute naloxone-precipitated morphine withdrawal were examined in the taste reactivity paradigm. Acute naloxone-precipitated withdrawal paired with sucrose solution established conditioned active rejection of the sucrose solution. Active rejection of sucrose was observed when naloxone was administered both 1 h and 22 h after morphine. When the stimulus properties of morphine were present during the conditioning trial, the conditioned sucrose aversion was only expressed when the rats were tested in the same drug state in which they had learned the aversion. However, when the stimulus properties of morphine were not present during conditioning, the aversion was expressed in the absence of the morphine state. The results suggest that palatability shifts can be conditioned to sucrose paired with acute morphine withdrawal.

Severe congenital neutropenia: a case study

Severe congenital neutropenia, or Kostmann syndrome, describes a rare autosomal recessive disorder in which the neutrophils fail to reach a mature and functional state. The infant with SCN often presents with severe infections beginning in the first month of life. Recently, treatment with recombinant granulocyte colony-stimulating factor has been found to be effective in reducing the mortality and morbidity of this often fatal disorder.

Pimozide does not shift palatability: separation of anhedonia from sensorimotor suppression by taste reactivity

Several "taste reactivity" studies of dopamine and reward have concluded that pimozide suppresses the hedonic reaction patterns normally elicited by sucrose but enhances aversive reaction patterns elicited by quinine. However, other taste reactivity studies have failed to find hedonic/aversive shifts in reaction patterns after dopamine antagonists or dopamine lesions. The divergent conclusions have come from two different laboratories. To resolve the controversy regarding dopamine blockade and palatability, the present study joined the two laboratories to investigate the effect of pimozide on taste reactivity patterns elicited by sucrose and quinine. The results replicated many (but not all) of the earlier findings and identified procedural factors responsible for different outcomes. Overall, the results provide evidence for sensorimotor effects of pimozide on taste reactivity but not for a hedonic shift in palatability. Pimozide suppressed both hedonic and aversive reaction patterns in a gradual sensorimotor fashion when the eliciting taste stimulus was repeated or continued for several minutes. The general suppression typically did not alter the initial reaction to a taste but emerged only after an oral infusion of sucrose or quinine continued for several minutes or trials. Aversive reactions were never enhanced. The balance between hedonic and aversive reaction patterns was not shifted by pimozide. We conclude that pimozide produces a sensorimotor impairment of taste reactivity patterns but does not shift taste palatability toward anhedonia or aversion.

Ibogaine interferes with the establishment of amphetamine place preference learning

The ability of ibogaine, injected 24 hr before amphetamine, to modify the establishment of amphetamine-induced place preference learning was assessed. A single injection of ibogaine blocked the establishment of amphetamine place preference after 1 or 2 conditioning trials, but it was less effective after 4 trials. The reduced effectiveness of ibogaine across multiple conditioning trials appears to be the result of the development of tolerance to ibogaine.

Induction chemoradiotherapy followed by esophagectomy in patients with carcinoma of the esophagus

BACKGROUND

Induction chemoradiotherapy followed by esophagectomy may provide results superior to those of single-modality treatment in patients with esophageal cancer. The purpose of this study was to review our experience with this approach for esophageal cancer.

METHODS

From 1988 to 1996, 166 consecutive patients with esophageal cancer were evaluated; 66 entered a protocol of chemotherapy (5-fluorouracil, cisplatin) concurrent with radiation (45 Gy) followed by esophagectomy. Fifty-four patients completed the protocol.

RESULTS

Toxicity associated with induction chemoradiotherapy was minimal. The actuarial survival at 12, 24, and 36 months was 59%, 42%, and 32%, respectively. The pathologic complete response (pCR) rate was 41%, with 12-, 24-, and 36-month survivals of 77%, 50%, and 45%, whereas non-pCR patients had survivals of 46%, 35%, and 23%. The difference in survival between pCR and non-pCR patients was not significant (p = 0.13), but the difference in recurrence-free survival was significant (p = 0.007).

CONCLUSIONS

This well-tolerated protocol resulted in a high pCR. Trimodality treatment for esophageal cancer may provide long-term survival in some patients regardless of their pCR status.

Recurrent alveolar proteinosis following double lung transplantation

We present a case of recurrent alveolar proteinosis following double lung transplantation.

Ibogaine interferes with the establishment of amphetamine place preference learning

The ability of ibogaine, injected 24 hr before amphetamine, to modify the establishment of amphetamine-induced place preference learning was assessed. A single injection of ibogaine blocked the establishment of amphetamine place preference after 1 or 2 conditioning trials, but it was less effective after 4 trials. The reduced effectiveness of ibogaine across multiple conditioning trials appears to be the result of the development of tolerance to ibogaine.

LSD produces place preference and flavor avoidance but does not produce flavor aversion in rats

The hedonic properties of lysergic acid diethylamide (LSD) were assessed using the place conditioning, taste reactivity, and taste avoidance tests. LSD produced a conditioned place preference, but only at the highest dose tested (0.2 mg/kg). A single preexposure to the conditioning chamber (latent inhibition) prevented the establishment of a place preference. When paired with sucrose, doses of 0.05 to 0.2 mg/kg of LSD produced taste avoidance, but no dose of LSD produced an aversion to the taste as assessed by the taste reactivity test. These results suggest that LSD, like other rewarding drugs, produces taste avoidance by a mechanism other than that produced by emetic drugs.

Primary pulmonary chondrosarcoma mimicking bronchogenic cyst on CT and MRI

Pulmonary chondrosarcoma is a rarely encountered primary tumor of the lung. We present a case with computed tomography and magnetic resonance imaging features mimicking a bronchogenic cyst.

Ibogaine fails to interrupt the expression of a previously established one-trial morphine place preference

1. Ibogaine, a proposed anti-addictive agent, has been found to interfere with the acquisition of a weak morphine-induced place preference. The present series of experiments determined if ibogaine would interfere with the expression of a previously established morphine (5 mg/kg) place preference. 2. A single injection of 40 mg/kg of ibogaine 24 h, 12 h or 4 h prior to the preference test (Experiment 1) or 80 mg/kg of ibogaine 24 hr prior to the preference test (Experiment 3) did not interfere with the expression of a morphine conditioned place preference. 3. Furthermore, two injections of 40 mg/kg of ibogaine 48 h and 24 h or 24 h and 4 h prior to testing (Experiment 2) did not interfere with the expression of a morphine place preference. 4. Ibogaine appears to be incapable of attenuating the expression of a previously established one-trial morphine place preference.

LSD produces place preference and flavor avoidance but does not produce flavor aversion in rats

The hedonic properties of lysergic acid diethylamide (LSD) were assessed using the place conditioning, taste reactivity, and taste avoidance tests. LSD produced a conditioned place preference, but only at the highest dose tested (0.2 mg/kg). A single preexposure to the conditioning chamber (latent inhibition) prevented the establishment of a place preference. When paired with sucrose, doses of 0.05 to 0.2 mg/kg of LSD produced taste avoidance, but no dose of LSD produced an aversion to the taste as assessed by the taste reactivity test. These results suggest that LSD, like other rewarding drugs, produces taste avoidance by a mechanism other than that produced by emetic drugs.

Individual differences in reactivity to the rewarding/aversive properties of drugs: assessment by taste and place conditioning

The ability of individual differences in the strength of conditioned taste avoidance (CTA) to predict strength of place conditioning produced by the same drug was assessed. In Phase 1, rats were assigned to High CTA and Low CTA groups on the basis of their intake of saccharin solution previously paired with morphine, amphetamine, lithium, or fenfluramine. In Phase 2, the rats received place conditioning training with the same drug used during Phase 1. The rats that displayed the strongest amphetamine-induced CTA also displayed the strongest amphetamine-induced place preference, suggesting that a common mechanism mediates both effects. On the other hand, the strength of the CTA was unrelated to the strength of the place preference or place aversion produced by morphine, lithium, or fenfluramine.

Morphine enhancement of sucrose palatability: analysis by the taste reactivity test

The ability of morphine to modify sucrose palatability was assessed by the taste reactivity test. In Experiment 1, rats were injected with morphine (0.0, 0.5, 2.0, and 10.0 mg/kg, subcutaneously), 30 min before receiving a 10-min intraoral infusion of 2% or 20% sucrose solution. A dose of 2.0 mg/kg morphine enhanced ingestive reactions elicited by both concentrations of sucrose solution. In Experiment 2, the interval between morphine pretreatment and the taste reactivity test was manipulated. Rats given 2.0 mg/kg morphine 30 or 120 min before testing displayed enhanced ingestive reactions elicited by 20% sucrose solution during the first 5 min of a 10-min test. The results support the hypothesis that morphine enhances the hedonic assessment of sucrose solution.

The effects of nicotine and nicotine withdrawal on taste reactivity

The effect of nicotine pretreatment on the palatability of flavored solutions was assessed using the taste reactivity test. In Experiment 1, low doses of nicotine [0.2-0.4 mg/kg, subcutaneously (s.c.)] suppressed the aversive taste properties of quinine and quinine-sucrose mixture and enhanced the hedonic taste properties of sucrose (0.4 mg/kg, s.c.) in rats that were nicotine naive. In Experiment 2, rats were chronically preexposed to nicotine or saline over a period of 21 pretreatment days. Tolerance developed to the ability of nicotine to enhance the palatability of sucrose. Furthermore, rats that were chronically preexposed to nicotine displayed enhanced hedonic evaluation of sucrose 24 h after nicotine was withdrawn. These results confirm human self-reports that withdrawal from nicotine dependency enhances the palatability of sweet-tasting foods.