Biomedical subjects
Publications and source records attributed to R S McConnell.
A case of sphenoid wing meningioma mimicking the presentation of a transient ischaemic attack (TIA) is described. Based on findings from neuroimaging in this case, possible explanations of the mechanism of this uncommon presentation of meningiomas are discussed and the literature is reviewed.
Patients who undergo decompressive craniectomy for intracranial hypertension often require interval cranioplasty. Many cranioplasty agents are currently in use. The authors suggest that storage of the patient's own bone flap in the subcutaneous tissue of the abdominal wall, is a safe, efficacious and cost-effective alternative to use of synthetic cranioplasty materials.
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This review evaluates the contribution of prenatal diagnosis to the understanding of intracranial cysts. We describe the outcome of 54 fetuses in which prenatal investigations indicated the presence of such lesions. The cysts were diagnosed between 20 and 30 weeks of gestation. Most (63%) were supratentorial and interhemispheric. There was only a single sylvian cyst. In the infratentorial compartment, median retrocerebellar cysts were predominant. Incisural cysts accounted for 14.8% of the series. Nine pregnancies were interrupted because of the presence of associated brain disorders. Forty-five children are alive. Thirty-four had neuropsychological tests. Cysts rarely progressed, most frequently stabilized and often regressed postnatally. Hydrocephalus was rare. In two cases delivery was precipitated at 36 weeks to allow urgent treatment of rapidly evolving cysts. Thirteen children (28.2%) were treated postnatally, in general for developing cysts. The median follow-up for the whole series exceeds 4 years. Behavior, neurological development, and intelligence are normal in 88% of the cases, and 91% have a normal neurological status. Prognosis at the time of the prenatal consultation was correct in 89% of the cases. We emphasize the value of prenatal magnetic resonance imaging and karyotype studies to limit risks of incorrect prognosis.
Genetic and environmental factors play roles in the aetiology of ruptured intracranial aneurysms. Hypertension has been reported as a risk factor for intracranial aneurysm haemorrhage. We have tested if genotypes at the angiotensin converting enzyme (ACE) gene locus are associated with ruptured intracranial aneurysms. The insertion/deletion polymorphism in the ACE gene was genotyped in 258 subjects presenting in East Anglia with ruptured intracranial aneurysms (confirmed at surgery or angiographically) and 299 controls from the same region. ACE allele frequencies were significantly different in the cases and the controls (alleles chi(2)(1)=4.67, p=0.03). The I allele was associated with aneurysm risk (odds ratio for I allele v D allele = 1.3 (95% CI=1.02-1-65); odds ratio for II v DD genotype = 1.67 (95% CI=1.04-2.66)). The I allele at the ACE locus is over-represented in subjects with ruptured intracranial aneurysms. These data are supported by non-significant trends in the same direction in two previous smaller studies. Thus, this allele may be associated with risk for ruptured intracranial aneurysms.
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We have optimized Ellman-type plasma and erythrocyte cholinesterase assays for the field determination of pesticide exposure. The assays employ stable, premixed, inexpensive colorimetric reagents and a simplified kinetic measurement procedure using a novel battery-operable light-emitting-diode-source colorimeter (LEDSC). These methods were compared to a field tintometric method for cholinesterase currently in widespread use, using samples from organophosphate-intoxicated hospitalized patients. In comparison to the colorimetric method, the tintometric method was less precise and consistently underestimated the extent of pesticide exposure. Methods for the effective field determination of pesticide exposure using cholinesterase assays are critically evaluated with regard to their practical, biochemical, and medical relevance.
We describe here a field method we developed for colorimetry of erythrocytic acetylcholinesterase (EC 3.1.1.7) in capillary blood samples. Three stable, premixed assay reagents and de-ionized water (but no centrifuge or balance) are required. This method, adapted for a microplate format, is essentially that of Ellman et al. (Biochem Pharmacol 1961;7:88-95) as modified by George and Abernethy (Clin Chem 1983;29:365-8). Assays were quantified and corrected for hematocrit by using a battery-powered colorimeter with a silicon carbide (blue) light-emitting-diode source. Advantages over existing field methods include better portability, ruggedness, greater precision, and lower cost per sample.