[Role of cannabinoid receptors in regulation of cardiac tolerance to ischemia and reperfusion]

Coronary artery occlusion (45 min) and reperfusion (2 h) were modeled in vivo in anesthetized artificially ventilated Wistar rats. Total ischemia (45 min) and reperfusion (30 min) of the isolated rat heart were performed in vitro. The selective agonist of cannabinoid (CB) receptors HU-210 was injected intravenously at a dose of 0.1 mg/kg 15 min prior to the coronary artery ligation. The selective CB1 antagonist SR141716A and the selective CB2 antagonist SR144528 were injected intravenously 25 min prior to ischemia. In vitro, HU-210 and SR141716A were added to the perfusion solution at the final concentrations of 0.1 microM prior to total ischemia. Preliminary injection of HU-210 reduced the infarct size-to-area at risk (IS/AAR) ratio in vivo. This cardioprotective effect was completely abolished by SR141716A but remained after SR144528 injection. Both antagonists had no effect on the IS/AAR ratio. Preliminary injection of the K(ATP) channel blocker glibenclamide did not abolish the cardioprotective effect of HU-210. The addition of HU-210 prior to ischemia reduced the creatine phosphokinase (CPK) level in the coronary effluent and decreased left ventricular developed pressure. SR141716A alone had no effect on cardiac contractility and CPK levels. These results suggest that cardiac CB1 receptor activation increases cardiac tolerance to ischemia-reperfusion and has a negative effect on the cardiac pump function. Endogenous cannabinoids are not involved in the regulation of cardiac contractility and tolerance to ischemia and reperfusion. ATP-sensitive E+ channels are not involved in the mechanism of the cardioprotective effect of HU-210.

Socioeconomic variations in women's diets: what is the role of perceptions of the local food environment?

OBJECTIVES

To test the contribution of perceived environmental factors (food availability, accessibility and affordability) to mediating socioeconomic variations in women's fruit, vegetable and fast food consumption.

METHODS

A community sample of 1580 women from 45 neighbourhoods provided survey data on their socioeconomic position (SEP) (education and income); diet (fruit, vegetable and fast food consumption); and the perceived availability of, access to and cost of healthy food in their local area.

RESULTS

Once perceived environmental variables were considered, the associations between SEP and diet were weak and non-significant, suggesting that socioeconomic differences in diet were almost wholly explained by perceptions of food availability, accessibility and affordability.

CONCLUSIONS

Strategies to decrease socioeconomic inequalities in diet could involve promoting inexpensive ways to increase fruit and vegetable consumption, and ensuring that people of low SEP are aware that many healthy foods are available at relatively low cost. Future research should also confirm if perceptions match objective measures of food availability, accessibility and affordability, in order to address the real and/or perceived lack of healthy options in low SEP neighbourhoods.

Comparison of [3H]-(2S,4R)-4-methylglutamate and [3H]d-aspartate as ligands for binding and autoradiographic analyses of glutamate transporters

While studies with [(3)H]D-aspartate ([(3)H]d-Asp) illustrate specific interactions with excitatory amino acid transporters (EAATs), new insights into the pharmacological characteristics and localization of specific EAAT subtypes depend upon the availability of novel ligands. One such ligand is [(3)H]-(2S,4R)-4-methylglutamate ([(3)H]4MG) which labels astrocytic EAATs in homogenate binding studies. This study examined the utility of [(3)H]4MG for binding and autoradiography in coronal sections of rat brain. Binding of [(3)H]4MG was optimal in 5mM HEPES buffer containing 96 mM NaCl, pH 7.5. Specific binding of [(3)H]4MG exhibited two components, but was to a single site when glutamate receptor (GluR) sites were masked with kainate (KA; 1 microM): t(1/2) approximately 5 min, K(d) 250 nM and B(max) 5.4 pmol/mg protein. Pharmacological studies revealed that [(3)H]4MG, unlike [(3)H]d-Asp, labeled both EAAT and ionotropic GluR sites. Further studies employed 6-cyano-7-nitroquinoxaline (30 microM) to block GluR sites, but selective EAAT ligands displayed lower potency than expected for binding to transporters relative to drugs possessing mixed transporter/receptor activities. Autoradiography in conjunction with densitometry with [(3)H]4MG and [(3)H]d-Asp revealed wide, but discrete distributions in forebrain; significant differences in binding levels were found in hippocampus, nucleus accumbens and cortical sub-areas. Although EAAT1 and EAAT2 components were detectable using 3-methylglutamate and serine-O-sulphate, respectively, the majority of [(3)H]4MG binding was to KA-related sites. Overall, in tissue sections [(3)H]4MG proved unsuitable for studying the autoradiographic localization of EAATs apparently due to its inability to selectively discriminate Na(+)-dependent binding to Glu transporters.

The advanced health and disaster aid network: a light-weight wireless medical system for triage

Advances in semiconductor technology have resulted in the creation of miniature medical embedded systems that can wirelessly monitor the vital signs of patients. These lightweight medical systems can aid providers in large disasters who become overwhelmed with the large number of patients, limited resources, and insufficient information. In a mass casualty incident, small embedded medical systems facilitate patient care, resource allocation, and real-time communication in the advanced health and disaster aid network (AID-N). We present the design of electronic triage tags on lightweight, embedded systems with limited memory and computational power. These electronic triage tags use noninvasive, biomedical sensors (pulse oximeter, electrocardiogram, and blood pressure cuff) to continuously monitor the vital signs of a patient and deliver pertinent information to first responders. This electronic triage system facilitates the seamless collection and dissemination of data from the incident site to key members of the distributed emergency response community. The real-time collection of data through a mesh network in a mass casualty drill was shown to approximately triple the number of times patients that were triaged compared with the traditional paper triage system.

[Significance of cardiac cannabinoid receptors in regulation of cardiac rhythm, myocardial contractility, and electrophysiologic processes in heart]

Intravenous administration of cannabinoid (CB) receptor agonists (HU-210, 0.1 mg/kg; ACPA, 0.125 mg/kg; methanandamide, 2.5 mg/kg; and anandamide, 2.5 mg/kg) induced bradycardia in chloralose-anesthetized rats irrespective of the solubilization method. Methanandamide, HU-210, and ACPA had no effect on the electrophysiological activity in the heart, while anandamide increased the duration of the QRS complex. The negative chronotropic effect of HU-210 was due to CB1 receptor activation since is was not observed after CB1 receptor blockade by SR141716A (1 mg/kg intravenously) but was present after pretreatment with CB2 receptor antagonist SR144528 (1 mg/kg intravenously). CB receptor antagonists SR141716A and SR144528 had no effect on cardiac rhythm or ECG indices. Hence, in the intact heart, endogenous CB receptor agonists are not involved in the regulation of cardiac rhythm and electrophysiological processes. The chronotropic effect of CBs was independent of the autonomic nervous system because it remained significant after autonomic ganglion blockade by hexamethonium (1 mg/kg intravenously). CB receptor activation by HU-210 (0.1 and 1 microM) in vitro decreased the rate and force of isolated heart contractions, the rates of contraction and relaxation, and end diastolic pressure. The negative chronotropic effect of HU-210 was less pronounced in vitro than in vivo. The maximum inotropic effect of HU-210 was reached at the concentration of 0.1 microM.

Negative chronotropic effect of cannabinoids and their water-soluble emulsion is related to activation of cardiac CB1 receptors

Intravenous injection of cannabinoids dissolved in cremophore EL:ethanol:NaCl mixture and water-soluble emulsion of the same cannabinoids caused identical negative chronotropic effects in chloralose-narcotized rats. Selective CB1 and CB2 receptor antagonist HU-210 also induced a negative chronotropic effect in rats, while pre-injection of CB1 receptor antagonist SR 141716A completely abolished this effect of HU-210. Selective CB2 receptor antagonist SR 144528 had no effect on HU-210-induced bradycardia. Preinjection of ganglioblocker hexamethonium also did not abolish the negative chronotropic effect of HU-210 and ACPA. Perfusion of isolated rat heart with Krebs-Henseleit solution containing HU-210 in a final concentration of 100 nM reduced heart rate. It was shown that the negative chronotropic effect of cannabinoids is mediated through activation of cardiac CB1 receptors.

Somatostatin receptor expression, tumour response, and quality of life in patients with advanced hepatocellular carcinoma treated with long-acting octreotide

Octreotide may extend survival in hepatocellular carcinoma (HCC). Forty-one per cent of HCCs have high-affinity somatostatin receptors. We aimed to determine the feasibility, safety, and activity of long-acting octreotide in advanced HCC; to identify the best method for assessing somatostatin receptor expression; to relate receptor expression to clinical outcomes; and to evaluate toxicity. Sixty-three patients with advanced HCC received intramuscular long-acting octreotide 20 mg monthly until progression or toxicity. Median age was 67 years (range 28–81 years), male 81%, Child–Pugh A 83%, and B 17%. The aetiologies of chronic liver disease were alcohol (22%), viral hepatitis (44%), and haemochromatosis (6%). Prior treatments for HCC included surgery (8%), chemotherapy (2%), local ablation (11%), and chemoembolisation (6%). One patient had an objective partial tumour response (2%, 95% CI 0–9%). Serum alpha-fetoprotein levels decreased more than 50% in four (6%). Median survival was 8 months. Thirty four of 61 patients (56%) had receptor expression detected by scintigraphy; no clear relationship with clinical outcomes was identified. There were few grade 3 or 4 toxicities: hyperglycaemia (8%), hypoglycaemia (2%), diarrhoea (5%), and anorexia (2%). Patients reported improvements in some symptoms, but no major changes in quality of life were detected. Long-acting octreotide is safe in advanced HCC. We found little evidence of anticancer activity. A definitive randomised trial would identify whether patients benefit from this treatment in other ways.

Comparative study of lymphoedema with axillary node dissection versus axillary node sampling with radiotherapy in patients undergoing breast conservation surgery

AIMS

Our aim was to compare the incidence of lymphoedema in two groups of patients undergoing breast conservation surgery; one undergoing axillary sampling and radiotherapy to patients with positive axillary nodes, and the other undergoing axillary clearance.

METHODS

Retrospective review of records of two sequential groups of patients; one undergoing axillary sampling between January 1994 and December 1998 (Group 1) and the other undergoing axillary clearance between January 2000 and December 2002 (Group 2). Both groups had minimum of 2 years follow-up.

RESULTS

Three hundred and twelve patients were included in Group 1 and 194 in Group 2. 2.2% of the patients in Group 1 developed lymphoedema compared to 12.3% in Group 2. This was statistically significant with a P value=0.0001. In the node-positive patients, the incidence of lymphoedema in Group 1 was 6.2% compared to 15.4% in Group 2, although the differences were not statistically significant with P=0.17.

CONCLUSIONS

The incidence of lymphoedema in the axillary sampling group was low, although the differences were less pronounced in the node-positive patients. The effectiveness of radiotherapy as an alternative to full axillary dissection among patients with positive nodes is currently under investigation in randomised controlled trials.

Liquid-based cytology can improve efficiency of cervical smear readers: evidence from timing surveys in two NHS cytology laboratories

OBJECTIVE

Cervical screening programmes in England and Wales were advised by the National Institute for Clinical Excellence in 2003 to adopt liquid-based cytology (LBC) in place of conventional Papanicolaou (Pap) cytology to facilitate laboratory efficiency. Pilot evaluations in England and Scotland monitored daily or weekly workloads of smear readers and concluded that LBC could increase hourly throughput rates. This study, instead, used timing surveys to determine screening rates.

METHODS

Two National Health Service cytology laboratories in Manchester and Stockport were partially converted to the LBC ThinPrep process for a cervical screening trial. Three 1-week timing surveys were conducted over 7 months. The surveys covered all LBC-trained staff. The first survey in Manchester also covered staff undertaking conventional Pap screening. The smear readers used timers to record time taken for examining and reporting each slide.

RESULTS

In Manchester, in the first survey, nearly 1 minute per slide was saved by the LBC method during primary microscopy. In both laboratories, the mean microscopy time for primary screening of LBC slides was reduced by almost 1 minute between the first and second surveys. There was no difference between the second and third surveys. Microscopy by cytopathologists was also 1 minute per slide quicker with LBC than conventional Pap. The LBC inadequate rates for both laboratories were <2.0%. Organizational factors impacted on the hourly LBC primary screening rates in the laboratories, the rate for Stockport being higher than the rates in the pilot evaluations.

CONCLUSIONS

The timing surveys confirm that the LBC ThinPrep technology can improve laboratory efficiency. However, decision-makers should also consider the overall costs and benefits of introducing the technology in screening programmes, including the capital investment and workforce implications.

Nuclear magnetic resonance spectroscopy of expressed prostatic secretions: Metabolite citrate and derivatives are potential markers of prostate cancer

4623

Background: Nuclear magnetic resonance spectroscopy (NMRS) along with a novel method for determining absolute concentrations of metabolites were utilized to analyze expressed prostatic secretions (EPS) from men with prostate cancer (PCa) and from healthy controls. Methods: Flash frozen EPS samples from 66 men (40 with PCa and 26 controls) were analyzed by high-resolution 1H-NMR spectroscopy using a Bruker 500 MHz DRX NMR spectrometer with a 1-mm microprobe. The total number of scans per fully relaxed 1H-NMR spectrum was n = 40 with water suppression. Absolute concentrations of endogenous metabolites (citrate, spermine, myo-inositol, lactate, alanine, phosphocholine, glutamate, acetate, hydroxybutyrate) were quantified using trimethylsilyl-propionic acid as an external standard reference. Stepwise multivariable logistic regression (LR) was used to model the risk of PCa based upon the levels of the measured metabolites. Results: The average age of the EPS donors was 54.7 ± 9.8 years. The median Gleason score for the men with PCa was 6 (range 5–9). The Wilcoxon rank sum test indicated that citrate, spermine, inositol, citrate/spermine, and citrate/lactate were all significant predictors of PCa (p < .001). The LR models indicated that the absolute concentration of citrate was highly predictive of PCa with lower concentrations resulting in a higher risk of cancer. The area under the receiver operating characteristic curve (AUROC) for citrate alone was 0.79 (95% CI 0.75–0.83). Using relative concentrations (metabolite ratios) in a two-variable LR model, citrate/spermine and citrate/lactate were also predictive of PCa with an AUROC of 0.76 (95% CI 0.71–0.81). Conclusions: The results suggest that absolute concentration of citrate and its derivatives in EPS as measured by NMRS have promising potential as accurate markers of prostate cancer.

No significant financial relationships to disclose.

Is availability of public open space equitable across areas?

This study examined whether availability of public open spaces that can be used for recreation varies according to neighbourhood socio-economic disadvantage. Density and area of public open spaces were examined using a geographic information system and postal boundaries were used to define neighbourhoods. Neighbourhood socio-economic status (SES) was stratified into quintiles. Once neighbourhood population and geographic area were considered there were no differences in the number or total area of free-access, restricted access or sporting/recreation open spaces across quintiles of neighbourhood SES. Future research should examine whether the quality of public open spaces differ by neighbourhood SES.

[Paticipation of cannabinoid receptors in the regulation of cardiac rhythm and cardiac contractility]

It has been found that i. v. administration of cannabinoid receptor (CB) agonists (HU-210, ACPA, anandamide, methanandamide) induced a decrease in the heart rate (HR) in anesthetized rats. Pretreatment with CB1 receptor antagonist SR141716A completely abolished a negative chronotropic effect of CB receptor agonist HU-210. The CB2 receptor antagonist SRI 44528 did not prevent a HU-210-induced decrease in the HR. Pretreatment with the ganglion blocker hexamethonium had no effect on the negative chronotropic action of HU-210. Addition of HU-210 (100 nM) to perfusion solution induced a decrease in the HR, left ventricular development pressure, rate of contractility and relaxation of isolated perfused rate heart without change in end diastolic pressure. These data suggest that cardiac CBI receptor activation induces a decrease in the HR both in vivo and in vitro. An occupancy of the same receptors mediates a negative inotropic effects of cannabinoids.

Postmortem diagnosis of chronic granulomatous disease: how worthwhile is it?

A previously healthy 11 year old boy died unexpectedly after a rapid course of progressive pneumonia. Postmortem microbiology and histopathology suggested an underlying diagnosis of chronic granulomatous disease. This was confirmed by neutrophil oxidative burst and gene mutation analysis of other family members, one of whom benefited from early bone marrow transplantation.

An investigation of psychological, social and environmental correlates of obesity and weight gain in young women

OBJECTIVES

This study explored the biological, psychological, social and environmental correlates of young women's current weight and retrospective 2-year weight change.

METHODS

A total of 790 young women (mean age 26.8 years), sampled from the Australian Longitudinal Study on Women's Health, provided self-reported data on their height and weight, sociodemographics and a range of biological, psychological, social and environmental variables.

RESULTS

Several variables from all domains (biological, psychological, social support and environmental) were correlated with higher body mass index, and less strongly greater 2-year weight change. Key correlates included the tendency to never put on weight, no matter what; self-efficacy for avoiding weight gain, and for healthy eating; attention paid to weight; family support and friends' support/sabotage of physical activity/healthy eating; and perceived difficulty of taking the stairs rather than the elevator as part of the daily routine.

CONCLUSIONS

Intervention strategies aimed at reducing weight gain and obesity may need to focus on social and environmental, as well as psychological factors; however, further research is necessary to confirm these findings given that a number of hypothesized associations were not observed.

Public views of the benefits and barriers to the consumption of a plant-based diet

OBJECTIVE

The aim of this study was to examine consumers' perceived benefits and barriers to the consumption of a plant-based diet.

DESIGN

Mail survey that included questions on perceived benefits and barriers to the consumption of a plant-based diet.

SETTING

Victoria, Australia.

SUBJECTS

Four hundred and fifteen randomly selected Victorian adults.

RESULTS

The main perceived barrier to adoption of a plant-based diet was a lack of information about plant-based diets (42% agreement). Sex, age and education differences were present in over a quarter of the barrier items. For example, non-university-educated respondents and older people were less willing to change their current eating pattern than were university educated and younger respondents. The main benefits associated with plant-based diets were health benefits, particularly decreased saturated fat intake (79% agreement), increased fibre intake (76%), and disease prevention (70%). Age, sex and education differences with regard to benefits were apparent, although sex differences were more important than age or education differences.

CONCLUSIONS

The majority of respondents perceived there to be health benefits associated with the consumption of a plant-based diet. Compared with the proportion of respondents who agreed that there were particular benefits of eating a plant-based diet, perceived barriers were relatively low. An understanding of the perceived benefits and barriers of consuming a plant-based diet will help formulate strategies that aim to influence beliefs about plant foods, plant food consumption, and, ultimately, public health.

Weight and place: a multilevel cross-sectional survey of area-level social disadvantage and overweight/obesity in Australia

OBJECTIVE

To estimate variation between small areas in adult body mass index (BMI), and assess the importance of area level socioeconomic disadvantage in predicting BMI.

METHODS

We identified all census collector districts (CCDs) in the 20 innermost Local Government Areas in metropolitan Melbourne, Australia, and ranked them by the percentage of low income households (< dollar 400/week). In all, 50 CCDs were randomly selected from the least, middle and most disadvantaged septiles of the ranked list and 4913 residents (61.4% participation rate) completed one of two surveys. Multilevel linear regression was used to estimate area level variance in BMI and the importance of area level socioeconomic disadvantage in predicting BMI.

RESULTS

There were significant variations in BMI between CCDs for women, even after adjustment for individual and area SES (P = 0.012); significant area variation was not found for men. Living in the most versus least disadvantaged areas was associated with an average difference in BMI of 1.08 kg/m2 (95% CI: 0.48-1.68 kg/m2) for women, and of 0.93 kg/m2 (95% CI: 0.32-1.55 kg/m2) for men. Living in the mid versus least disadvantaged areas were associated with an average difference in BMI of 0.67 kg/m2 (95% CI: 0.09-1.26 kg/m2) for women, and 0.43 kg/m2 for men (95% CI: -0.16-1.01).

CONCLUSION

These findings suggest that area disadvantage is an important predictor of adult BMI, and support the need to focus on improving local environments to reduce socioeconomic inequalities in overweight and obesity.

Why do women of low socioeconomic status have poorer dietary behaviours than women of higher socioeconomic status? A qualitative exploration

In developed countries, persons of low socioeconomic status (SES) are generally less likely to consume diets consistent with dietary guidelines. Little is known about the mechanisms that underlie SES differences in eating behaviours. Since women are often responsible for dietary choices within households, this qualitative study investigated factors that may contribute to socioeconomic inequalities in dietary behaviour among women. Semi-structured interviews were conducted with 19 high-, 19 mid- and 18 low- SES women, recruited from Melbourne, Australia, using an area-level indicator of SES. An ecological framework, in which individual, social and environmental level influences on diet were considered, was used to guide the development of interview questions and interpretation of the data. Thematic analysis was undertaken to identify the main themes emerging from the data. Several key influences varied by SES. These included food-related values such as health consciousness, and a lack of time due to family commitments (more salient among higher SES women), as well as perceived high cost of healthy eating and lack of time due to work commitments (more important for low SES women). Reported availability of and access to good quality healthy foods did not differ strikingly across SES groups. Public health strategies aimed at reducing SES inequalities in diet might focus on promoting healthy diets that are low cost, as well as promoting time-efficient food preparation strategies for all women.

Consumers' readiness to eat a plant-based diet

OBJECTIVE

The aim of this study was to examine consumers' readiness to change to a plant-based diet.

DESIGN

Mail survey that included questions on readiness to change, eating habits and perceived benefits and barriers to the consumption of a plant-based diet.

SETTING

Victoria, Australia.

SUBJECTS

A total of 415 randomly selected adults.

RESULTS

In terms of their readiness to eat a plant-based diet, the majority (58%) of participants were in the precontemplation stage of change, while 14% were in contemplation/preparation, and 28% in action/maintenance. Those in the action/maintenance stage ate more fruit, vegetables, nuts, seeds, whole-meal bread, and cooked cereals than those in earlier stages. There were statistically significant differences in age and vegetarian status between the stages of change, but not for other demographic variables. There were strong differences across the stages of change with regard to perceived benefits and barriers to plant-based diets. For example, those in action/maintenance scored highest for benefit factors associated with well-being, weight, health, convenience and finances, whereas those in the precontemplation stage did not recognise such benefits.

CONCLUSIONS

These findings can be utilised to help provide appropriate nutrition education and advertising, targeted at specific stages of change. For example, education about how it is possible to obtain iron and protein from a plant-based diet and on the benefits of change, in addition to tips on how to make a gradual, easy transition to a plant-based diet, could help progress precontemplators to later stages.

SPONSORSHIP

Australian Research Council.

Increasing central adiposity: the Nepean longitudinal study of young people aged 7–8 to 12–13 y

BACKGROUND

Estimates of the prevalence of overweight and obesity in young people are typically based on body mass index (BMI). However, BMI may not indicate the level of central adiposity. Waist circumference has therefore been recommended to identify young people at risk of morbidity associated with central adiposity.

OBJECTIVE

To investigate (a) change in total and central adiposity between 7-8 and 12-13 y (b) agreement between classifying young people as overweight or obese based on total adiposity and central adiposity, and (c) risk factors associated with the development of total and central adiposity.

DESIGN

Anthropometric measurements were taken on 342 children in 1996/97 and 5 y later. Risk factors examined included birth weight, physical activity, TV viewing, pubertal status, parental adiposity, diet and socio-economic status.

RESULTS

Between 7-8 and 12-13 y indices of central adiposity increased more than total adiposity; waist circumference z-score increased by (mean+/-s.d.) 0.74+/-0.92 and BMI z-score increased by 0.18+/-0.67. At 12-13 y there was moderate agreement between the two measures of adiposity (weighted kappa=0.64). However, waist circumference identified a greater number of young people as overweight or obese compared to BMI (41.2 vs 29.3%, P<0.001). Adiposity status at 7-8 y, maternal obesity, and pubertal stage were the strongest predictors of BMI status at 12-13 y. Risk factors associated with increased central adiposity were similar.

CONCLUSIONS

Overweight and obesity, as measured by waist circumference, is a bigger problem than is currently assessed by BMI. Targeting known risk factors for total adiposity may be an appropriate strategy for preventing increased central adiposity.