Unusual traumatic rupture of the thoracic aorta with avulsion of the left subclavian artery]

Of the many cases of traumatic rupture of the aorta diagnosed each year at l"H?pital du Sacré-Coeur, Montreal, most patients are already in irreversible shock when seen. However, during the period Oct. 1, 1974 to Sept. 30, 1975, prompt surgical treatment saved six patients. One of these six patients had a complete trans-section of the aortic arch between the left carotid and left subclavian arteries with avulsion and slight retraction of the left subclavian artery. Repair of the aortic arch and left subclavian artery was accomplished without extracorporeal circulation. A sutureless temporary bypass shunt was created by (a) cannulating the ascending and descending aorta, the cannulas being secured with purse-string sutures and joined by a 3/8-inch (94-mm) polyvinyl chloride (PVC) tube connected to a "double T" adapter, and (b) joining two small PVC tubes from the adapter with two straight cannulas, a no. 14 being inserted into the innominate artery and a no. 12 being inserted into the left carotid artery. With this temporary bypass created, the ascending and descending aorta and aortic arch vessels were all clamped. Aortic continuity was re-established with a tubular Dacron graft (diameter, 19 mm) to which was anastomosed a side-arm of knitted Dacron (diameter, 10 mm) to repair the left subclavian artery. Throughout the temporary perfusion the brain, spinal cord and all abdominal viscera were well protected. No sign of ventricular distension was detected. This report is the first in which complete transsection of the aortic arch has been managed by a sutureless bypass shunt allowing perfusion of all aortic arch vessels without extracorporeal circulation.     

Purification and mass spectroscopic analysis of human CB2 cannabinoid receptor expressed in the baculovirus system

Abstract: The cannabinergic system is present in a variety of organs and tissues that perform a wide range of essential physiologic functions making it an inherently important therapeutic target for drug discovery. In order to augment our knowledge regarding the interactions between cannabinoid receptors (CBs) and their ligands, efficient and effective tools are essential for robust expression and purification of these membrane‐bound proteins. In this report, we describe a suitable method for purification of the human cannabinoid receptor 2 (CB2) to a qualitative and quantitative level sufficient for mass spectral analysis. We utilized a baculovirus expression system, incorporating several epitope tags to facilitate purification and to ameliorate the effect the tags have on CB2 expression and function. Expressed protein encoded by a carboxy (C)‐terminal His‐tagged CB2 construct displayed a B_max value of 9.3 pmol/mg with a K_D of 7.30 nm using [3_H]CP–55⁹⁴⁰, a standard cannabinoid radioligand, and was selected for subsequent purification experiments. Western blot analysis of purified membrane protein yielded several forms of CB2, the most abundant being a 41 kDa peptide. A second protein species was observed with an apparent molecular weight of 46 kDa representing a glycosylated form of CB2. In addition, a CB2 homodimer was also identified. The purified receptor was subjected to mass spectroscopic analysis to confirm its identity and purity. Mass spectra corresponding to the intracellular, extracellular and transmembrane domains were obtained. These experiments exemplify the importance of high‐level expression systems when developing membrane‐bound protein purification strategies. This work will aid in the identification of receptor–ligand binding sites, the characterization of molecular features involved in receptor activation, and the elucidation of the CB2 receptor tertiary structure.     

Auditing paediatric diabetes care and the impact of a specialist nurse trained in paediatric diabetes

AIMS: To define outcome measures for auditing the clinical care of children and adolescents with insulin dependent diabetes mellitus (IDDM) and to assess the benefit of appointing a dedicated paediatric trained diabetes specialist nurse (PDSN). METHODS: Retrospective analysis of medical notes and hospital records. Glycaemic control, growth, weight gain, microvascular complications, school absence, and the proportion of children undergoing an annual clinical review and diabetes education session were assessed. The effect of the appointment of a PDSN on the frequency of hospital admission, length of inpatient stay, and outpatient attendance was evaluated. RESULTS: Children with IDDM were of normal height and grew well for three years after diagnosis, but grew suboptimally thereafter. Weight gain was above average every year after diagnosis. Glycaemic control was poor at all ages with only 16% of children having an acceptable glycated haemoglobin. Eighty five per cent of patients underwent a formal annual clinical review, of whom 16% had background retinopathy and 20% microalbuminuria in one or more samples. After appointing the PDSN the median length of hospital stay for newly diagnosed patients decreased from five days to one day, with 10 of 24 children not admitted. None of the latter was admitted during the next year. There was no evidence of the PDSN affecting the frequency of readmission or length of stay of children with established IDDM. Non-attendance at the outpatient clinic was reduced from a median of 19 to 10%. CONCLUSIONS: Outcome measures for evaluating the care of children with IDDM can be defined and evaluated. Specialist nursing support markedly reduces the length of hospital stay of newly diagnosed patients without sacrificing the quality of care.     

Inflammatory bowel disease and predisposition to osteopenia

The prevalence of osteopenia in children with inflammatory bowel disease (IBD) is unknown. The effect of nutritional state, disease activity, and steroid therapy on bone mineral content (BMC) of whole body, lumbar spine, and left femoral neck measured by dual energy x ray absorptiometry in 32 children with IBD was assessed by comparison with 58 healthy local school children. Using the control data, a predicted BMC was calculated taking into account bone area, age, height, weight, and pubertal stage. The measured BMC in children with IBD was expressed as a percentage of this predicted value (% BMC). Mean (SD) % BMC was significantly reduced for the whole body and left femoral neck in the children with IBD (97.0 (4.5)% and 93.1 (12.0)% respectively, p < 0.05). Of the children with IBD, 41% had a % BMC less than 1 SD below the mean for the whole body and 47% at the femoral neck. Reduction in % BMC was associated with steroid usage but not with the magnitude of steroid dose, disease activity, or biochemical markers of bone metabolism. In conclusion, osteopenia is relatively common in childhood IBD and may be partly related to the previous use of steroids.     

Tuberous sclerosis complex and Wolff-Parkinson-White syndrome

This report highlights the association between tuberous sclerosis and Wolff-Parkinson-White syndrome. Ten patients with concurrent diagnoses of Wolff-Parkinson-White syndrome and tuberous sclerosis were identified. Wolff-Parkinson-White syndrome presented early in life, nine cases being diagnosed in the first year. Eight of the 10 cases were male. In eight cases, the syndrome was associated with supraventricular tachycardias, and in nine with cardiac rhabdomyomata. One child died from cardiac failure secondary to obstruction of the left ventricular outflow tract by a rhabdomyoma. Five of nine survivors showed resolution of Wolff-Parkinson-White syndrome on follow up. The accessory pathway was localised in nine patients from surface electrocardiograms: six children had left sided pathways and three had right sided pathways.