A quantitative analysis of CT and cognitive measures in normal aging and Alzheimer's disease

Patients with presumptive Alzheimer's disease (AD) and healthy community volunteers received computed tomographic (CT) brain scans and cognitive tests. The CT scans were quantitatively analyzed with a semiautomated thresholding technique to derive volumetric measures of cerebrospinal fluid (CSF)-to-tissue ratios in six regions of interest (ROIs): lateral ventricles; vertex sulci, frontal sulci, Sylvian fissures, parieto-occipital sulci, and third ventricle. Regression analysis was performed on CT data from 85 older volunteers (ages 51-82) to generate age norms for each ROI. Within this group, tissue loss, as measured by the % CSF in each ROI, was highly correlated with age, although each ROI showed different rates of change over age. For all ROIs, the AD group had significantly more tissue loss than expected in normal aging. In addition, AD patients with a presenescent onset (before age 65) tended to have greater vertex sulcal and frontal sulcal tissue reduction than AD patients with a senescent onset (age 65 or after). When regional tissue reduction, corrected for age, was correlated with cognitive test scores, two sets of double dissociations emerged within the AD group: large CT z scores (i.e., decreased tissue and increased CSF) of frontal sulci, but not of the third ventricle, correlated with low Comprehension and Boston Naming Test scores, whereas large CT z scores of the third ventricle, but not of the frontal sulci, correlated with low scores on Digit Symbol and Picture Arrangement. These results suggest that heterogeneity of structural and functional integrity exists among patients with AD.     

Nephron‐sparing surgery for small incidental renal cell carcinoma

Background : Nephron‐sparing surgery is currently an accepted treatment for renal cell carcinomas in patients with bilateral tumours, solitary kidneys and when overall renal function is impaired or at risk from medical disease. Its role in patients with a normal contralateral kidney remains controversial. Methods : The authors’ experience in 23 patients undergoing partial nephrectomy for small peripheral lesions between 1995 and 2000 is reported here. Results : Twenty‐three patients (13 men and 10 women) with a mean age of 56 years underwent partial nephrectomy. All but three of these patients had a normal contralateral kidney. Mean operating time was 141 min with a mean reduction of haemoglobin of 28 g/dL. Three patients required transfusion. Serum creatinine did not change significantly between preoperative and postoperative values. Two JJ stents were placed prophylactically during surgery to minimize urinary leak. There were no intraoperative or early postoperative deaths and at mean follow up of 16 months there was no evidence of recurrent tumour in 23 patients. Seventeen per cent of lesions removed were benign. Conclusions : Partial nephrectomy for small peripheral lesions is a safe procedure with low morbidity. No definite recurrences are evident at an early stage of follow up, although longer review (probably more than 10 years) will be required to assess cancer‐specific survival following this procedure.     

Electrophysiological studies on the effects of intrathecal morphine on nociceptive neurones in the rat dorsal horn

We have studied the effects of intrathecal morphine on the responses of 38 dorsal horn neurones in the intact rat under halothane anaesthesia to A and C fibre electrical stimulation and to natural stimuli applied to their receptive fields. Morphine selectively reduced the C fibre and pinch evoked activity in a dose-dependent naloxone-reversible manner with an ED50 of 7 nmoles. The 'wind-up' of neurones to repetitive stimulation was little altered except with the highest doses (50-150 nmoles) tested. By contrast, the A fibre evoked responses of the neurones were only slightly reduced by morphine and both the tactile responses and receptive field size to innocuous stimuli enhanced for certain cells. The results are discussed in relation to the spinal actions of opiates and their clinical applications.