Cannabis containing equivalent concentrations of delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) induces less state anxiety than THC-dominant cannabis

RATIONALE

Delta-9-tetrahydrocannabinol (THC), an active component of cannabis, can cause anxiety in some users during intoxication. Cannabidiol (CBD), another constituent of cannabis, has anxiolytic properties suggesting that cannabis products containing CBD in addition to THC may produce less anxiety than THC-only products. Findings to date around this issue have been inconclusive and could conceivably depend on moderating factors such as baseline anxiety levels in users.

OBJECTIVE

The present study examined whether anxiety following single doses of vaporised THC, CBD and THC/CBD might be explained by state and trait anxiety levels at baseline.

METHODS

A placebo-controlled, randomised, within-subjects study including 26 healthy recreational cannabis users tested the effects of vaporised THC-dominant cannabis (13.75 mg THC), CBD-dominant cannabis (13.75 mg CBD), THC/CBD-equivalent cannabis (13.75 mg THC/13.75 mg CBD) and placebo cannabis on anxiety. Self-rated trait anxiety was assessed with the State-Trait Anxiety Inventory (STAI). State levels of anxiety were objectively assessed with a computer-based emotional Stroop task (EST) and subjectively rated with the STAI-state questionnaire and a visual analogue scale.

RESULTS

Both THC and THC/CBD significantly increased self-rated state anxiety compared to placebo. State anxiety after THC/CBD was significantly lower than after THC alone. THC-induced anxiety was independent of anxiety at baseline. When baseline anxiety was low, CBD completely counteracted THC-induced anxiety; however, when baseline anxiety was high, CBD did not counteract THC-induced anxiety. There were no effects of any treatment condition on the EST.

CONCLUSION

Overall, the study demonstrated that the THC/CBD-equivalent cannabis induces less state anxiety than THC-dominant cannabis.

Tackling smoking among out of school youth in South Africa: An analysis of friendship ties

Background

Friendships during adolescence play a significant role in the initiation and maintenance of tobacco use. Smoking behaviour among adolescent friends has not been explored among out of school youth (OSY) in South Africa. Out of school youth (OSY), described as those between 13 and 20 years old, have not completed their schooling and are not currently enrolled in school, are at greater risk for tobacco use.

Aim

The main aim of this study is to examine whether the smoking behaviour of OSY is associated with that of their OSY friends.

Methods

Respondent driven sampling was used to recruit OSY and their OSY friends. A mixed effects logistic regression with a random intercept across school-province combinations was used to analyse survey data. Race and gender were also incorporated into the analyses as effect moderators (n = 391).

Results

Results of this study confirm that cigarette smoking was common among OSY and their OSY friends, with 53.5% of the respondents smoking in the past month (SD = 0.44). When OSY friends were either all non-smokers or half their friends were non-smokers, Coloured (mixed race) OSY were less likely to smoke compared to Black African and Other (mostly Asian descent) OSY.

Conclusion

Cultural norms and values associated with the different race groups may play a role in the smoking behaviour of out of school youth friends. Understanding this relationship is useful for identifying those OSY that are vulnerable to the behaviours that place them at risk of tobacco related morbidity and mortality.

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Smoking was common among out of school youth and their out of school youth friends.

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Racial differences were found in out of school youth smoking and their friends.

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Cultural norms and values influence smoking behaviour of out of school youth friends.

The insights of health and welfare professionals on hurdles that impede economic evaluations of welfare interventions

BACKGROUND

Four hurdles associated with economic evaluations in welfare interventions were identified and discussed in a previous published literature review. These hurdles include (i) 'Ignoring the impact of condition-specific outcomes', (ii) 'Ignoring the impact of QoL externalities', (iii) 'Calculation of costs from a too narrow perspective' and (iv) 'The lack of well-described & standardized interventions'. This study aims to determine how healthcare providers and social workers experience and deal with these hurdles in practice and what solutions or new insights they would suggest.

METHODS

Twenty-two professionals of welfare interventions carried out in Flanders, were interviewed about the four described hurdles using a semi-structured interview. A thematic framework was developed to enable the qualitative analysis. The analysis of the semi-structured interviews was facilitated through the use of the software program QRS NVivo 10.

RESULTS

The interviews revealed a clear need to tackle these hurdles. The interviewees confirmed that further study of condition-specific outcomes in economic evaluations are needed, especially in the field of mental health and stress. The proposed dimensions for the condition-specific questionnaires varied however between the groups of interviewees (i.e. general practitioners vs social workers). With respect to QoL externalities, the interviewees confirmed that welfare interventions have an impact on the social environment of the patient (friends and family). There was however no consensus on how this impact of QoL externalities should be taken into account in welfare interventions. Professionals also suggested that besides health care costs, the impact of welfare interventions on work productivity, the patients' social life and other items should be incorporated. Standardization appears to be of limited added value for most of the interviewees because they need a certain degree of freedom to interpret the intervention. Furthermore, the target population of the interventions is diverse which requires a tailor-made approach.

CONCLUSION

This qualitative research demonstrated that these hurdles occur in practice. The proposed solutions for these hurdles can contribute to the improvement of the methodological quality of economic evaluations of welfare interventions.

Non-destructive determination of maize leaf and canopy chlorophyll content

The objective of this study was to develop a rapid non-destructive technique to estimate total chlorophyll (Chl) content in a maize canopy using Chl content in a single leaf. The approach was (1) to calibrate and validate a reflectance-based non-destructive technique to estimate leaf Chl in maize; (2) to quantify the relative contribution of each leaf Chl to the total Chl in the canopy; and (3) to establish a relationship between leaf Chl content and total Chl in a maize canopy. The Red Edge Chlorophyll Index CI(red edge)=(R(NIR)/R(red edge))-1 based on reflectances, R, in the red edge (720-730nm) and near infrared (770-800nm) was found to be an accurate measure of maize leaf Chl. It was able to predict leaf Chl ranging from 10 to 805mgChlm(-2) with root mean-square error less than 38mgChlm(-2). Relationships between Chl content in each maize leaf and total canopy Chl content were established and showed that Chl in the collar leaf before silking or ear leaves explained more than 80% and 87% of the variation in total Chl in a maize canopy, respectively. Thus, non-destructive measurements of both reflectance and area of a single leaf (either collar or ear) can be used to accurately estimate total Chl content in a maize canopy.

Comparison of perfusion MRI by flow-sensitive alternating inversion recovery and dynamic susceptibility contrast in rats with permanent middle cerebral artery occlusion

We compared cerebral blood flow (CBF) parameters obtained by dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) with those obtained by flow-sensitive alternating inversion recovery (FAIR) in brain regions with different perfusion levels in rats with permanent middle cerebral artery (MCA) occlusion. MCA occlusion was performed in 19 rats. T2-weighted MRI, FAIR and DSC-MRI were performed within 48 h after occlusion. CBF parameters were analyzed in regions of interest with either prolonged or less prolonged mean transit time (MTT). Ratios of ipsi- vs contralateral CBF values were calculated and tested for correlation and differences between FAIR and DSC-MRI. FAIR-aCBF ratios correlated significantly with DSC-rCBF ratios. The mean FAIR-aCBF ratio was significantly lower than mean DSC-rCBF ratio in the area with prolonged MTT. In the area with less prolonged MTT, the mean FAIR-aCBF ratio and mean DSC-rCBF values did not differ significantly. We conclude that FAIR correlates with DSC-MRI if perfusion is preserved. FAIR provides lower CBF values than DSC-MRI if perfusion is reduced and MTT is prolonged. This probable underestimation of perfusion may be caused by transit delays. Care should be taken when quantifying CBF with FAIR and when comparing the results of FAIR- and DSC-MRI in areas with hypoperfusion.

Magnetic resonance imaging in experimental subarachnoid haemorrhage

BACKGROUND

We developed an MRI protocol to measure cerebrovascular diameter and blood flow velocity, and if we could detect cerebrovascular alterations after SAH and their impact on cerebral ischaemia.

METHOD

SAH was induced in 15 Wistar rats by means of the endovascular filament method; 6 other rats served as control. MRI measurements were performed on a 4.7T NMR spectrometer 1 and 48 hours after SAH and 9 days thereafter. Diffusion-weighted and T2-weighted images were acquired to detect cerebral ischaemia. The arterial spin labelling method was used to measure CBF. MR angiography was used to measure vessel diameter and blood flow velocity, from which the arterial blood flow was calculated.

FINDINGS

The ischemic lesion volume increased between 1 and 48 hours after SAH from 0.039 to 0.26 ml (P = 0.003). CBF decreased from 53.6 to 39.1 ml/100 g/min. The vessel diameter had narrowed, the blood flow velocity diminished as did the arterial blood flow in most vessels, but only the vasoconstriction in the right proximal ICA reached significance (0.49 mm to 0.43 mm, P = 0.016). Baseline values were restored at day 9.

CONCLUSIONS

We showed that it is feasible to detect alterations of in-vivo vessel diameter and blood flow velocities and their consequences for brain damage after experimental SAH in the rat. The growth of the infarct volume between day 0 and 2 after SAH and the parallel vasoconstriction suggest that delayed cerebral ischaemia after SAH occurs in rats and that this may be caused by vasoconstriction.

The time course of ischemic damage and cerebral perfusion in a rat model of space-occupying cerebral infarction

We aimed to establish a rat model of space-occupying hemispheric infarction to evaluate potential treatment strategies. For adequate timing of therapy in future experiments, we studied the development of tissue damage, edema formation, and perfusion over time with different MRI techniques. Permanent middle cerebral artery (MCA) occlusion was performed in 32 Fisher-344 rats. Forty-six MRI experiments including diffusion weighted (DW), T2-weighted (T2W), flow-sensitive alternating inversion recovery (FAIR) perfusion-weighted, and T1-weighted (T1W) imaging before and after gadolinium were performed at 1, 3, 8, 16, 24, and 48 h of ischemia. MCA occlusion consistently led to infarction of the complete MCA territory. Mortality was 75%. Lesion volumes as derived from apparent diffusion coefficient (ADC) and T2 maps increased to maximum values of 400+/-48 mm3 at 24 h and 420+/-54 mm3 at 48 h of ischemia, respectively. Midline shift peaked at 24 h. The area with diffusion-perfusion deficit decreased to a minimum at 24 h after onset of ischemia and perfusion of the contralateral hemisphere dropped at the same time point. Leakage of gadolinium through the blood-brain barrier in the entire infarct occurred within 3 h of ischemia. Permanent intraluminal MCA occlusion in Fisher-344 rats is an adequate model for space-occupying cerebral infarction. Rats may benefit from intervention aimed at reducing tissue shift and intracranial pressure (ICP), and at improving cerebral blood flow, if initiated before 24 h after MCA occlusion. The value of treatment modalities depending on an intact blood-brain barrier should be questioned.

Delayed decompressive surgery increases apparent diffusion coefficient and improves peri-infarct perfusion in rats with space-occupying cerebral infarction

BACKGROUND AND PURPOSE

There is no conclusive experimental support that decompressive surgery in late stages of space-occupying cerebral infarction will improve outcome. We studied the effects of delayed decompressive surgery on the development of tissue damage, edema formation, and cerebral perfusion with different MRI techniques in a rat model of space-occupying cerebral infarction.

METHODS

Permanent middle cerebral artery (MCA) occlusion was performed in 6 Fisher 344 rats. Decompressive surgery was performed 17 hours after the occlusion. Each animal was assessed before surgery and 2 and 4 hours after surgery by means, of diffusion-weighted T2-weighted, and flow-sensitive alternating inversion recovery perfusion-weighted MRI. Ischemic damage was also evaluated in hematoxylin-eosin-stained brain sections.

RESULTS

Lesion volume as derived from apparent diffusion coefficient (ADC) maps decreased from 522+/-98 mm3 before to 405+/-100 mm3 (P=0.016) 4 hours after decompressive surgery, whereas lesion volume from T2 maps increased from 420+/-66 mm3 before to 510+/-92 mm3 (P=0.048) 4 hours after decompressive surgery. Midline shift decreased from 1.4+/-0.1 mm to 0.5+/-0.2 mm (P=0.001). Blood flow in the noninfarcted area of the ipsilateral hemisphere improved from 25+/-9 mL/min/100 g of tissue to 38+/-9 mL/min/100 g of tissue (P=0.035). Despite the pseudonormalization of ADC, irreversible damage was found in the entire MCA territory on histological evaluation.

CONCLUSIONS

In rats with space-occupying cerebral infarction, delayed decompressive surgery leads to a decrease in lesion volume derived from ADC maps, which is probably because of an increase of extracellular water formation. There are no signs that this reflects rescue of ischemic tissue.

Analysis of three Ptx2 splice variants on transcriptional activity and differential expression pattern in the brain

Three different transcripts of the homeodomain gene termed pituitary homeobox (Ptx) 2 (Pitx2/Brx/Rieg/Solurshin/Arp) were cloned from different species encoding proteins belonging to the paired-like family of homeodomain proteins. Ptx2a (324 amino acids), Ptx2b (271 amino acids), and Ptx2c (318 amino acids) share the C terminus, including the homeodomain, and have different N termini. Here we report the comparative analysis of all three different Ptx2 splice variants for their transcriptional activity and their expression pattern in the adult rat brain. Ptx2 is able to trans-activate via different model promoters in different cell lines. A mild difference in trans-activating potential is observed among the splice variants, but the underlying mechanism is at present unknown. It is surprising that all Ptx2 transcripts displayed an identical expression pattern in the brain. This markedly restricted pattern is limited to the following brain areas: the anterior and intermediate lobes of the pituitary gland, the subthalamic nucleus, the posterior hypothalamic nucleus, the mammillary bodies, the red nucleus, and the deep gray layer of the superior colliculus. The data presented suggest that all variants of Ptx2 are involved in the development and regulation of distinct neuronal cell groups and the pituitary gland.

Cyclophosphamide, epirubicin and cisplatin (CEP) versus epirubicin plus cisplatin (EP) in stage Ic-IV ovarian cancer: a randomized phase III trial of the Gynecologic Oncology Group of the Comprehensive Cancer Center Limburg

Cisplatin is the most important drug in the treatment of advanced ovarian cancer. The role of anthracyclines is controversial. We compared a combination of epirubicin plus cisplatin (EP) with a regimen of cyclophosphamide, epirubicin and cisplatin (CEP). Patients with stage Ic-IV ovarian cancer were randomized to receive either epirubicin 100 mg/m2 plus cisplatin 75 mg/m2 q 4 weeks or cyclophosphamide 500 mg/m2 plus epirubicin 75 mg/m2 plus cisplatin 50 mg/m2 q 4 weeks, which we considered the reference treatment based on our previous experience. Patients were initially debulked, followed by six cycles of chemotherapy, or in case primary debulking was insufficient or considered inappropriate, secondary debulking was attempted in selected cases after sufficient chemotherapy-induced regression. Optimal debulking was defined as residual lesions < or = 2 cm. A total of 210 patients (191 eligible) were randomized. Results did not show significant differences in all major endpoints (pathologically documented complete response and survival). The median survival for all patients was 34 months, for patients with stage III 26 months, for patients with stage IV 20 months and it has not been reached for patients with stage Ic-II. As no significant differences between an equitoxic regimen of EP and CEP were detected, it might be more useful to look again at the anthracyclines as part of combination chemotherapy instead of the alkylating agents.

Correlation of bovine viral diarrhoea virus induced cytopathic effects with expression of a biotype-specific marker

The purpose of this study was the identification antigenic differences between cytopathic (cp) and noncytopathic (ncp) bovine viral diarrhoea viruses (BVDV). Cells infected with 19 strains of each viral biotype were analyzed for reactivity with the monoclonal antibody (mab) BVD/C38. Reactivity was examined using an enzyme immunoassay on fixed infected monolayers of fetal calf kidney cells. In the majority of cases, the mab discriminated between cells infected with each of the two viral biotypes. Three reactivity patterns could be distinguished. Most cpBVDV strains yielded monolayers where 80-100% of infected cells reacted with the mab. Most of the ncpBVDV infected cells showed either no reaction, or only single cells of foci were stained. However, about one third of either cp- or ncpBVDV strains tested yielded infected monolayers where 30-50% of the cells reacted with the antibody. Cell damage other than the typical cytopathic effect might be responsible for the BVD/C38 reactivity of cells infected with BVDV. In addition, it was analyzed whether the antigenic marker associated with cpBVDV was expressed in cells infected with viral isolates from 21 animals with clinical mucosal disease. In 14 cases cpBVDV was isolated and the antigenic marker was found throughout. In seven cases ncpBVDV was cultivated and the antigenic marker was detected in four isolates.

[Incidence and prognostic significance of inducible ventricular arrhythmias in the early post-infarction phase]

To identify patients at risk of sudden cardiac death or sustained ventricular tachycardia (VT) after recent acute myocardial infarction, 100 patients younger than 70 years (80 male, 20 female; 47 anterior wall infarction, 53 inferior wall infarction) were studied prospectively. 25 days (mean) after onset of myocardial infarction, programmed ventricular stimulation was performed, including the introduction of single (S2) and double (S2-S3) ventricular extrastimuli both during sinus rhythm and at paced ventricular cycle lengths (S1-S1) of 500, 430, 370, and 330 ms. The end of the protocol was reached as soon as 4 or more consecutive ventricular echo beats (VE) were initiated. Four or more VE were initiated in 46% of patients, 4 to 9 VE in 21%, greater than or equal to 10 VE or sustained VT in 25%. During follow-up (15 +/- 8 months), 5 patients died suddenly (less than or equal to 1 h), and 5 further patients developed spontaneous sustained ventricular tachycardia. In 3 patients who died suddenly and 4 with spontaneous sustained VT, greater than or equal to 4 VE had been induced by programmed ventricular stimulation (sensitivity 60% and 80% respectively). With regard to sudden cardiac death and spontaneous ventricular tachycardia, the predictive value of a positive test was 15%, that of a negative (normal) test 94%. False negative results occurred in 6%, whereas 85% of all abnormal results had to be regarded as false positive, as these patients did not develop an arrhythmic event during follow-up. Thus patients after recent myocardial infarction frequently have signs of increased ventricular vulnerability during programmed ventricular stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)