The effects of hyponatraemia and subarachnoid haemorrhage on the cerebral vasomotor responses of the rabbit

Impairment of cerebral autoregulation and development of hyponatraemia are both implicated in the pathogenesis of delayed cerebral ischaemia and infarction following subarachnoid haemorrhage (SAH) but the pathophysiology and interactions involved are not fully understood. We have studied the effects of hyponatraemia and SAH on the cerebral vasomotor responses of the rabbit. Cerebrovascular reactivity to hypercapnia and cerebral autoregulation to trimetaphan-induced hypotension were determined in normal and hyponatraemic rabbits before and 6 days after experimental SAH produced by two intracisternal injections of autologous blood. Hyponatraemia (mean plasma sodium of 119 mM) was induced gradually over 48 h by administration of Desmopressin and intraperitoneal 5% dextrose. Sham animals received normal saline. The cerebrovascular reactivity (% change +/- SD in cortical CBF/mm Hg PaCO2, measured by hydrogen clearance) of hyponatraemic (4.8 +/- 3.0%) and SAH (1.3 +/- 2.0%) animals was significantly less (p less than 0.05) than control (11.6 +/- 4.0%) and sham (8 +/- 2.0%) animals, whereas the reactivity of hyponatraemic-SAH animals was preserved (9.8 +/- 6.0%). Hyponatraemia and SAH alone each significantly impaired CBF autoregulation but their combined effects were not additive. Systemic hyponatraemia impairs normal cerebral vasomotor responses but does not augment the effects of experimental SAH in the rabbit.     

The genesis and development of creative activity

During the sixties many studies of creativity focussed upon the evaluation of outcomes or products and gave little serious attention to the study of the genesis and development of the cognitive abilities responsible for the products. As a result, creativity assessment was delayed until the child had developed the verbal and other expressive abilities necessary for product-orientated assessment and creativity was deprived of an adequate developmental theory.

This paper offers an explanation of creativity within a developmental constructivist framework. The focus is upon the nature of creative activity and not upon the evaluation of products. There is an attempt to demonstrate that creative activity may be observed from early infancy and that this early transformational activity increases in structural and contextual complexity as the individual develops.     

Follow up of patients with colorectal polyps: are the BSG guidelines being adhered to?

OBJECTIVE: The publication of the BSG guidelines in 2002 provided a framework for the follow up of patients with colorectal polyps. The aim of the present study was to determine whether they had, or were being correctly adhered to in a moderately sized District General Hospital. METHOD: A total of 598 patients were on the waiting list for colonoscopy at Airedale General Hospital (AGH) in February 2005. Of these, 203 were being followed up as a result of the previous finding of a polyp. RESULTS: Only 14.8% of patients had been or were being followed up according to the BSG guidelines. The majority of the 85.2% of patients who did not comply with follow up did so as a result of over investigation. Seventy-eight per cent of the low-risk group and 55% of the intermediate-risk group had been colonoscoped, or were waiting to have colonoscopy, too soon or too frequently according to the BSG guidelines. Twenty-four patients with hyperplastic polyps were being followed up incorrectly, as were 17 patients discovered to have a polyp pathology on flexible sigmoidoscopy. It was established that 131 extra colonoscopies had been, or were planned to be performed unnecessarily. CONCLUSION: These data have major implications with regard to patient safety, service provision and cost to the NHS.     

Comparative bactericidal exposures for selected oral bacteria using carbon dioxide laser radiation

Although relatively high CO2 laser energies have been shown to sterilize root canals, the response of several bacterial strains to decreasing exposures of CO2 laser energy remains unknown. Freshly grown bacterial cells were irradiated on glass microscope coverslips. A comparison of equivalent energy exposures with differing parameters was made on the bacterial viability. No statistically significant difference was found in the energy required to kill closely related bacterial species. However, the energy density required to kill greater than 99.5% of the bacteria is less than 200 J/cm2, much less than that shown to sterilize in a previous study.     

Giant hepatic hemangiomas: diagnostic and therapeutic dilemmas

This report describes four cases of surgically treated giant hepatic hemangiomas which illustrate some diagnostic and therapeutic difficulties encountered in the management of this condition. An important diagnostic triad has emerged, which should alert the physician to the possibility of a complicated hepatic hemangioma: the clinical signs of an acute inflammatory liver process contrasted with a normal white blood cell count and liver function tests. Hemangiomas of the left lobe were either missed or poorly demonstrated on selective hepatic angiographic examination, and in two patients the diagnosis was made only at the time of laparotomy. Hepatic resection was successfully performed in all patients; there was minimal morbidity and none of the patients died. In two patients with multiple hemangiomas, only symptomatic or easily resectable lesions were removed. All patients are alive and well; three have been followed up for more than 5 years. We conclude that resection in asymptomatic cases should be carried out only in those cases that require a diagnostic laparotomy and in those where the lesion is easily resectable. The majority of patients with symptomatic and complicated tumors should undergo resection, but even in these patients continued conservative treatment is appropriate when the risk of major resection outweighs the small risk of live-threatening bleeding.