Potency trends of cannabis in Jamaica during the period of 2014 to 2020.

Reports suggest that cannabis potency has dramatically increased over the last decade in the USA and Europe. Cannabinoids are the terpeno-phenolic compounds found in the cannabis plant and are responsible for its pharmacological activity. The two most prominent cannabinoids are delta-9-tetrahydrocannabinol (Δ9 THC) and cannabidiol (CBD). Cannabis potency is measured not only by the Δ9 THC levels but also by the ratio of Δ9 THC to other non-psychoactive cannabinoids, namely, CBD. Cannabis use was decriminalized in Jamaica in 2015, which opened the gates for the creation of a regulated medical cannabis industry in the country. To date, there is no information available on the potency of cannabis in Jamaica. In this study, the cannabinoid content of Jamaican-grown cannabis was examined over the period 2014-2020. Two hundred ninety-nine herbal cannabis samples were received from 12 parishes across the island, and the levels of the major cannabinoids were determined using gas chromatography-mass spectrometry. There was a significant increase (p < 0.05) in the median total THC levels of cannabis samples tested between 2014 (1.1%) and 2020 (10.2%). The highest median THC was detected in the central parish of Manchester (21.1%). During the period, THC/CBD ratios increased from 2.1 (2014) to 194.1 (2020), and there was a corresponding increase in the percent freshness of samples (CBN/THC ratios <0.013). The data show that a significant increase in the potency of locally grown cannabis has occurred in Jamaica during the last decade.

Pre-clinical grades predict clinical performance in the MBBS stage II examination at the University of the West Indies, Mona Campus.

In the preclinical sciences, statistically significant predictive values have been reported between the performances in one discipline and the others, supporting the hypothesis that students who perform well in one discipline were likely to perform well in the other disciplines. We therefore decided to conduct a retrospective study to investigate the predictive effects of preclinical subjects on clinical subjects from 87 students of The University of the West Indies (UWI), Mona Campus who took the MBBS Stage II examination at various times between May 2000 and May 2002. The grade in Pathology was significantly predicted by scores in Anatomy and Pharmacology; Medicine by Physiology and Pharmacology scores; Surgery by Anatomy and Social and Preventive Medicine scores; while, the Obstetrics and Gynecology grade was predicted by the Anatomy score. The results support the hypothesis that the scores in some preclinical subjects can predict the performance in specific clinical subjects, which could be interpreted to suggest that poor performance in specific preclinical disciplines could be a warning sign of future poor performance in the related clinical disciplines.

Comparison and prediction of preclinical students' performance in the MBBS stage I examination at the University of the West Indies, Mona Campus.

This retrospective study involved the analysis of the grades of ninety-four preclinical students who took the Bachelor of Medicine and Bachelor of Surgery (MBBS) Stage I Examination in Anatomy, Biochemistry, Physiology, Social and Preventive Medicine, and Pharmacology between December 1997 and May 1999 at the Mona Campus of The University of the West Indies (UWI). A statistically significant correlation was observed among the basic science subjects. Additionally, a statistically significant prediction was found between the performances of the students in one discipline and the others, with Physiology being the most predicted. The data support the hypothesis that students who performed well in one discipline were likely to perform well in the other disciplines; and also that the performance in some subjects could predict the performance in others. This result may also justify further investigation as to whether the performance in certain basic sciences disciplines at the preclinical stage can be used to predict performance in the clinical disciplines.

A comparison of student performance in multiple-choice and long essay questions in the MBBS stage I physiology examination at the University of the West Indies (Mona Campus).

This retrospective study compared the performance of preclinical medical students in the multiple-choice question (MCQ) and long essay question components of a comprehensive physiology final examination. During the 3 yr analyzed, 307 students had an average score of 47% (SD 9.9) in the long essay questions and 64% (SD 9.9) in the MCQs. Regression analysis showed a significant correlation (r = 0.62, P < 0.01) between MCQs and long essay questions. When student performance was grouped by final course grade, a statistically significant correlation between MCQ and long essay scores existed only for the 210 students who received a passing grade (r = 0.20, P < 0.01). The MCQ and long essay question scores were not correlated for the 57 students who failed (r = 0.25, P = 0.06) or for the 40 students who achieved honors and distinctions (r = -0.27, P = 0.11). MCQ scores were significantly higher (P < 0.01) than essay scores for each of the groups when analyzed by two-way ANOVA. The results of this study suggest that for most students, the strong correlation between scores on MCQs and essay questions indicates that student performance was independent of testing format. For students at either end on the performance spectrum, the lack of correlation suggests that the performance in one of the testing formats had a strong influence on the final course grade. In addition, those students who failed the course were likely to be weak in both testing modalities, whereas students in all grade groups were more likely to perform better in the MCQs than in the long essay questions.

Stress, marijuana and addiction in an animal model [abstract]

OBJECTIVE: Acute stress has been shown in rats to increase self-administration for drugs such as cocaine, morphine and amphetamine. We aimed to explore this phenomenon for marijuana extract (ME) and its psychoactive component, 9-tetra-hydrocannabinol ( 9 THC). METHODS: Six female Sprague Dawley rats were followed free access to a black grid-floored chamber and a white one with a floor strewn with wood shavings. The time spent in each chamber indicated a preference for the black chamber. On alternate days of an 8-day conditioning period, six Sprague Dawley rats were first subjected to an acute stress for 10 minutes followed by an intraperitoneal administration of ME (saline vehicle) or 2m/kg 9 THC (oil vehicle). The doses used were those which had been previously shown to have neither aversive nor rewarding effects. The rats were then confined to the white chamber. On the other days, the rats were administered the respective vehicle and confined to the black chamber. After this conditioning period, the rats were once again allowed free access to the chambers and the pre-conditioning period times in each chamber were compared to the post-conditioning times. The stressors were: restraint stress (RS), swimming stress (SS) or acute isolation stress (ACI). RESULTS: When ME was administered with RS, the mean time spent in the drug+stress chamber increased compared with the pre-conditioning time with a significance level of p= 0.07. This result was repeated with 2 mg/kg of 9-tetrahydrocannabinol (p= 0.07). The ACI + ME combination resulted in an increase, which was significant (p< 0.05). CONCLUSIONS: Our results provide some evidence to support a possible influence of acute stress on reward to marijuana. There is also some indication that different types of stressors have different effects on this stress and drug reward association. (AU)

Effects of hormone replacement therapy on mesolimbic extracellular dopamine stress: an in vivo microdialysis study

OBJECTIVE: To determine the effects of hormone replacement therapy on dopamine (DA) release in the nucleus accumbens septi (NAS) of rats following footshock stress and to correlate these effects with locomotory behaviour. DESIGN AND METHODS: Thirty-two Long Evans rats were ovariectomized and treated with oestradiol benzoate, progesterone or oil (control group). Rats were stereotaxically implanted with guide cannulae in the NAS and dialysis probes used to sample the extra-cellular fluid (ECF). Following baseline measurements, intermittent footshocks were delivered for 10 minutes, and dialysate DA levels and locomotor activity assessed over 20 minute intervals for 2 hours by high performance liquid chromatography and a photocell activity monitor, respectively. RESULTS: At baseline, hormone replacement significantly decreased DA levels in the NAS. Oestrogen treated rats had the lowest DA release at baseline (p<0.001). Following footshock, all groups exhibited significant increases in DA levels; oestrogen treated rats showed the most significant relative increase, but absolute levels remained lowest. Locomotor activity at baseline was highest in oestrogen treated rats and showed no change after footshock, remaining higher than in other groups. All other groups showed relative increase in activity after footshock (p=0.02). CONCLUSIONS: Oestrogen pre-treatment depresses baseline DA level in the NAS, but enhances relative levels after footshock, while suppressing changes in locomotor activity. There is a general reciprocal relationship between DA levels within ECF and locomotor activity in all groups. This finding may have implications for understanding of the processes regulated by NAS dopamine, e.g. addiction or associative learning.(Au)

Hormonal variations influences learning - abstract

The study attempted to evaluate the influence of hormonal status (gender and oestrous cycle) on learning in male and female rats and to determine whether this difference was affected by dopamine agonists (cocaine and amphetamine). Rats were exposed to foot-shocks in a Y-maze. Exploratory and avoidance behaviours were tested on two trials, 24 hours following conditioning (Trial 1) and 2 weeks subsequently (Trial 2). Amphetamine (1mg/kg/ml) stimulated exploratory behaviour, whereas cocaine (1mg/kg/ml) had a depressant effect at Trial 1. Avoidance learning of a potentially dangerous environment was significantly less in oestrous than in diestrous and male rats. These results provide evidence that hormonal status influences learning. Cocaine and amphetamine given in a single low doses did not produce any significant effects on avoidance learning(AU)

Ethics and law in the medical curriculum: a University of the West Indies perspective

The Faculty of Medical Sciences (FMS), University of the West Indies, recognises that ethics and law are not currently given adequate importance in the training of health professionals. FMS also recognises the rapid advancement of technology, such as transplants, artificial organs, in vitro fertilization, life-sustaining equipment and euthanasia, as well as the ever-increasing prevalence of malpractice. Thus two conferences were held to consider the implementation of ethics and law in the medical curriculum. The conferences recommended an increased input into the curriculum of ethics and law, and that this programme be taught and examined in all the medical years. The article discusses implementation strategies (AU)

Mesolimbic deficits exacerbate amphetamine treatment: clinical implications for drug abusers

Amphetamine, a common drug used by abusers, is able to produce a schizophreniform psychosis in man. The experiment reported here examined amphetamine in relation to its role in the nucleus accumbens septi (NAS) and the globus pallidus. The effects produced by apomorphine, a direct dopamine (DA) agonist, were compared with those of amphetamine, a known indirect DA agonist. The data revealed that amphetamine in NAS-lesioned animals produced very active stereotypy which intensified with time. This effect was blocked by pallidal lesioning. Apomorphine in pallidectomised rats produced persistent stereotypy, but of diminished intensity. The results are discussed in terms of the mediating roles of the NAS and globus pallidus on behavioural sequelae. (AU)

Progress in medical education in the Faculty of Medical Sciences, University of the West Indies: Implementation of problem-based learning at the St Augustine Campus

This paper reviews some of the developmental procedures regarding changes in medical education within the Faculty of Medical Sciences, University of the West Indies. Discussed are some of the constraints experienced in attempting curriculum changes in the established medical school at Mona, Jamaica, as compared with the implementation of a problem-based learning strategy curriculum at the Eric Williams Medical Complex, St Augustine, Trinidad and Tobago. At Mona, integration of disciplines, community-health and other programmes were attempted. However, it was at the Eric Williams Medical Complex, a new school, that the Faculty of Medical Sciences was able to implement a problem-based programme. (AU)

Ultrastructural and neuropharmacological findings in the nerve/muscle system of a digenean (Cercaria caribbea LXXI Cable)

The surface morphology and organization of the neuromuscular system in Cercaria caribbea LXXI are investigated using scanning and transmission electron microscopy, respectively. Direct and indirect (sarconeural) nerve-muscle junctions are identified in the cercarial tail. Synaptic vesicles at the direct neuromuscular junction suggest cholinergic and aminoacidergic transmission. Those at the sarconeural junctions suggest catecholaminergic and/or serotonergic transmission. Acetylcholinesterase and non-specific cholinesterases were found in high concentrations in the proximal and distal tail. Flourescence histochemistry showed primary catecholamines and 5-HT in the body and tail. 5-HT in the tail may represent a slowly depleted store, perhaps associated with energy availability and utilization. (AU)

Photoreceptor evoked potentials and phototactic behaviour in cercaria caribbea LXXI cable

Transient potential changes evoked in response to light stimuli, and presumably arising from rhabdomeric eye-spots in the cercarial body, were recorded for the first time, to our knowledge, in helminth parasites. Pigmented Cercaria caribbea LXXI gave a very slowly adapting response to maintained light stimulus, while a non-pigmented variety appeared to emit a stronger, rapidly adapting response to light onset. Swimming towards a directional light source is disrupted by several neurophamacological agents, which presumably disturb synaptic transmission in the nerve/muscle system. The light evoked potentials were unaffected by these same agents and therefore, appeared to be directly recorded receptor potentials.(AU)

The neurophysiological control and photosensory modulation of swimming in a cercaria, Cercaria caribbea LXXI

Scanning and transmission electron microscopy revealed that Cercaria caribbea LXXI has a small body (70 æm) with a pair of well-developed, rhabdomeric photoreceptors; and a large tail (4 mm) with six longitudinal, striated muscle bands. Muscle cells had an outer myofibrillar region adjecent to the tergument and an inner sarcoplasmic region, prolongations of which, may form sarconeural junctions. Sarcomere lengths were consistent with invertebrate fast muscle fibres. Diffuse Z-bands and the presence of numerous mitochondria are consistent with slow muscle fibres, adapted for prolonged work output. Interneuronal junctions with abundant electron-lucent and electron-dense vesicles, and neuromuscular junctions with mainly electron-lucent presynaptic vesicles were demonstrated. The neuromuscular connection between the body and tail appeared to be restricted to a single axon, implying that modulation of tail activity by the body may involve simple triggering or level setting actions, rather than complex modulation. The Falck-Hillarp Formaldehyde-Induced Fluorescence and the Gomori techniques indicated that the neuromuscular system utilizes primary catecholamines, serotonic (5-HT) and an acetylcholine-like transmitter. There were indications that 5-HT promotes activity and is held as a non-replenishable store, depleted through time within the cercarial tail. Exogenous application of a range of neuropharmacological agents, profoundly affected survivorship of the organism. Of the catecholaminergis group, propranolol (1.1-4 æM) and haloperidol (0.066-0.133 mM) most effectively reduced population half-line (T50). This was followed by the cholinergic agent, physostigmine (0.08-2.5 mM). The gamma-aminobutyric acid antagonist, picrotoxin (0.08-2.5mM), only weakly affected T50. Several drugs, especially reserpine (0.08-2.5mM), produced osmotic disturbances, leading to shortened life span. Survivorship was also dependent on pH, with a sharply defined tolerance range between pH 6 and 8. Suction electrodes recordings of electrical activity in the tail revealed spontaneous spike potentials (0.2-0.6 mV, 15-20/sec) superimposed on an underlying slow wave component. The effects of drugs on this activity were observed. 5-HT increased the amplitude and frequency of spike discharge from 0.2 mV to 0.8 mV and 15/sec to 25/sec, respectively. Physostigmine was the most effective reducer of both parameters. Indications were that cholinergic receptors in the nerve network may be excitatory nicotinic and inhibitory muscarinic. Excitatory beta adrenergic and inhibitory dopaminergic influences were observed. C. caribbea LXXI exhibited strong positive phototaxis. In response to light stimuli, the pigmented cercariae gave a maintained receptor potential with a small transient component. In the non-pigmented strain of C. caribbea LXXI, the photosensory receptor potential showed a large transient and a small maintained component. Drugs did not alter the photosensory response. A drug-induced decrease in linear translation towards a photic stimulus was therefore due to a disturbance in the neuromuscular system (AU)

Progress in medical education in the Faculty of Medical Sciences, the University of the West Indies: implementation of problem-based learned at St. Augustine campus

This paper reviews some of the developmental procedures regarding changes in Medical Education within the Faculty of Medical Sciences, The University of the West Indies. Discussed are some of the constraints experienced in attempting curriculum changes in the established Medical School at Mona, Jamaica, as compared with the implementation of a problem-based learning strategy curriculum at the Eric Williams Medical Complex, St. Augustine, Trinidad and Tobago. At Mona, integration of disciplines, Community-Health and other programmes were attempted. However, it was at the Eric Williams Medical Complex, a new school, that the Faculty of Medical Sciences was able to implement a Problem-based programme.(AU)