The Effect of Subacute Marijuana Smoke Inhalation on Experimentally Induced Dermonecrosis by S. Aureus Infection

Dermonecrosis was induced in ICR mice by subcutaneous implantation of Staphylococcus aureus absorbed onto sterile cotton pellets. This model was used to assess the effects of marijuana smoke, marijuana placebo smoke and $DL⁹-tetrahydrocan-nabinol ($DL⁹-THC) on the local immune response to bacterial infection. Mice were exposed to 40 or 80 “puffs” of marijuana smoke, marijuana placebo smoke or air daily for 4 consecutive days. The estimated dose of $DL⁹THC per day generated from 40 or 80 puffs of marijuana smoke was 3.2 and 6.4 mg/kg, respectively. A group of sentinel (Shelf) control mice were included in each experiment. The necrotic index (NI) of mice exposed to 40 or 80 puffs of marijuana smoke were 67% and 44% of control, respectively. Air exposed mice showed a necrotic index comparable to the shelf control group. In chronically (60 days) exposed mice (80 puffs per day) the necrotic index was about 12% of control, while air-exposed mice were about 40% of control.

Placebo marijuana smoke exposed mice had a NI comparable to that of marijuana smoke exposed mice which suggested that the reduction in NI was unrelated to the pychomimetic component $DL⁹THC. To further explore which of the constituents of marijuana were responsible for the decreased NI, the ethanol extract from marijuana leaves was partioned between water (cannabinoid free) and chloroform (cannabinoid rich). Injection of the cannabinoid free fraction produced comparable decrease in the NI as observed with whole marijuana smoke, while the cannabinoid rich fraction produced no effect. $DL⁹THC at a dose of 10 mg/kg per day did not alter the NI.     

Pheochromocytoma and pregnancy: a case report and review of anesthetic management

PURPOSE: To describe a patient diagnosed with pheochromocytoma in the third trimester of pregnancy and discuss the perioperative and anesthetic management. CLINICAL FEATURES: A 32-yr-old previously healthy woman (gravida 4, para 2) presented to our tertiary care obstetrical hospital at 34 weeks five days gestation with a history of labile blood pressure and severe hypertension. A week prior to admission she began having episodes of severe headache, dizziness, sweating and nausea. On a routine obstetric visit she was noted to be severely hypertensive with a blood pressure of 200/120 mmHg. Biochemical investigations confirmed the diagnosis of pheochromocytoma and magnetic resonance imaging demonstrated a 3 cm x 3 cm right adrenal mass. The patient was invasively monitored in the intensive care unit and treated with alpha- followed by beta-blockade with phenoxybenzamine and metoprolol. A multidisciplinary conference was organized involving endocrinology, anesthesiology, general surgery and obstetrics to determine the most appropriate management of the patient. An uncomplicated laparoscopic adrenalectomy was performed following a period of recovery after an uneventful elective Cesarean delivery. CONCLUSIONS: The primary goals in the management of pheochromocytoma in pregnancy are early diagnosis, avoidance of a hypertensive crisis during delivery and definitive surgical treatment. Timing of surgical resection will depend on the gestational age at which diagnosis is made. Cesarean section is the preferred mode of delivery when the tumour is still present. This case illustrates that with antenatal diagnosis, advanced methods of tumour localization, adequate preoperative adrenergic blockade and team planning, pheochromocytoma in pregnancy can be treated successfully.     

Physical aggression towards others in adults with learning disabilities: prevalence and associated factors

Background Many people with learning disabilities (LD) show aggressive behaviour, but the extent of the problem and its associated factors and effects are unclear. Methods A cross‐sectional analysis was carried out using interview data from 3065 adults with LD on the Leicestershire LD Register. Physical aggression towards others was defined as carers reporting frequent (more than three times per week) and/or severe episodes. Individuals with and without aggression were compared using multiple logistic regression models for potential physical and psychological factors. Results Carers reported that 443 (14%) of adults were physically aggressive towards others. Men (P = 0.001), younger individuals (P < 0.001), people with more severe LD (P < 0.001) and those in institutional settings (P < 0.001) had a significantly higher prevalence of physical aggression. People with Down syndrome had a lower prevalence of physical aggression (P < 0.001). After adjustment, we found no relationship between aggression and the presence of epilepsy or autism. Among psychological factors, symptoms of frustration (P < 0.001) and mood swings (P < 0.001) were associated with higher levels of aggression. Failure to cope among carers was reported by 14% overall: 42% of people caring for adults with aggression said they were unable to cope compared with 10% of those caring for adults without aggression. Conclusions Physical aggression towards other people presents a significant challenge to carers of adults with LD. Further research is needed to identify aetiological factors with a view to finding effective interventions to reduce, and improve management of, this behaviour.     

Post-herpetic neuralgia and topical capsaicin

Topical 0.025% capsaicin was used to treat 33 patients with post-herpetic neuralgia (PHN). Thirty-nine percent of those entering the trial achieved at least a good result and 55% were improved or better. Fifty-six percent of the 23 patients completing the study had good or excellent pain relief after 4 weeks. Seventy-eight percent of the 23 noted at least some improvement in pain. Post-capsaicin burning was a common, untoward effect in most patients and in about one-third was so unbearable that the trial was terminated prematurely. This treatment appears to be a useful modality in PHN, particularly in the elderly in whom oral medications are often poorly tolerated; however, it does require supervision. A double-blind, controlled trial is now necessary.     

A new model of embolic stroke produced by photochemical injury to the carotid artery in the rat

We report a new model of embolic stroke in the rat, based on endothelial disruption and platelet aggregation in the carotid artery, which leads to distal embolization and focal brain infarction. The common carotid artery was irradiated for 6.5 minutes with the focused beam of an argon laser operated at a wavelength of 514.5 nm with a peak power of 2 W and an average power of 400 mw. Ipsilateral cerebral infarcts, ranging in size from 0.1 to 1.7 mm, were produced by platelet emboli in 12 of 13 rats. A total of 44 infarcts were observed in the 12 rats: 29 in the cortex, 6 in the hippocampus, 5 in the thalamus, and 4 in the basal ganglia. Scanning electron microscopy identified platelet aggregates in the carotid artery and in a deep cortical arteriole 50 minutes after the photochemical lesion. Twenty-four hours after the experiment, scanning electron microscopy of the carotid artery revealed damaged endothelium but few remaining adherent platelets. More intense laser irradiation in 8 rats, leading to carotid occlusion, produced an infarct in only 1. This new model can be used to study the acute and chronic pathological changes in the brain associated with platelet embolism.     

Gastrin: growth enhancing effects on human gastric and colonic tumour cells

Two colorectal (HT29, LoVo) and one gastric (MKN45) human tumour cell lines were examined for their in vitro trophic response to human gastrin-17. MKN45 and HT29 responded by increased 75Se selenomethionine uptake to exogenous gastrin (139 +/- 5.5% and 123 +/- 3% of control values respectively) whereas LoVo showed no significant response to this hormone. When these same cell lines were grown as xenografts in nude mice, similar responses were seen to exogenously administered human gastrin-17 (10 micrograms mouse-1 day-1, subcutaneous injection). MKN45 xenografts showed a greater response to continuously administered gastrin (osmotic mini-pumps, (10 micrograms mouse-1 day-1) when compared to the same dose given via a subcutaneous bolus injection. The hormone-treated xenografts had a two-fold increase in tumour cross-sectional area and growth rate when compared to saline-treated controls. Dose-response studies revealed that 0.4 micrograms gastrin mouse-1 day-1 appeared to be the minimally effective dose. As gastric and colorectal tumour cells show a trophic response to gastrin, antagonists of the gastrin receptor may prevent this effect causing tumour stasis. The gastric tumour cell line, MKN45, is gastrin-responsive and would be an ideal model for screening potent receptor antagonists.