Effect of exogenous surfactant on total respiratory system compliance

We measured total respiratory system compliance (Crs) before and after instilling 25 mg artificial surfactant in 1 ml saline down the endotracheal tube of preterm babies requiring resuscitation at birth, and compared results with data from 6 similar babies receiving saline only. Surfactant did not produce a significant improvement in Crs.     

Should the guidelines for monitoring serum cholesterol levels in the elderly be re-evaluated?

Elevated circulating cholesterol can have profound effects on the health of an individual. Such excess cholesterol can promote coronary artery disease, production and accumulation of β-amyloid in the brain, and possibly Alzheimer’s disease (AD). In a clinical trial evaluating the benefit of a cholesterol-lowering drug in the treatment of AD, mean cholesterol levels at baseline among individuals participating in the trial were found to be relatively high. Based on this observation we suggest that cholesterol levels should be actively monitored in the elderly, as many individuals with AD are over 65 years of age and therefore excluded by currently accepted guidelines.     

Whole body protein metabolism in children with cancer

Whole body protein synthesis and catabolism were measured using the [ring-2H5]phenylalanine and [1-13C]leucine primed constant infusion technique in 32 paediatric patients with cancer at different stages of treatment. Rates of synthesis (S) and catabolism (C) derived from the [ring-2H5]phenylalanine and [1-13C]leucine models were 4.7 (SD 1.3) (S) and 6.0 (1.5) (C) g/d/kg, and 5.5 (0.8) (S) and 6.8 (1.2) (C) g/d/kg, respectively. These results show that these two tracer techniques give similar results in this study population. Comparison of these values with results previously reported for groups of control children using the [ring-2H5]phenylalanine model (S = 3.69 and 3.93; C = 4.09 and 4.28 g/d/kg) and the [1-13C]leucine model (S = 4.32; C = 4.85 g/d/kg) show that rates of synthesis and catabolism were higher in cancer patients than in controls. Thus whole body protein turnover is increased in children under treatment for cancer. Other indices of metabolism such as plasma amino acids and intermediary metabolites were also measured and showed that, although subjects were in isotopic steady state, there were significant metabolic changes during the course of the primed constant infusions used to measure protein turnover.     

Rotator cuff tear: clinical experience with sonographic detection

Between June 1986 and April 1988, 86 sonographic examinations of the shoulder were performed on patients suspected of having rotator cuff tears. Major sonographic diagnostic criteria included (a) a well-defined discontinuity usually visible as a hypoechoic focus within the cuff, (b) nonvisualization of the cuff and (c) an echogenic focus within the cuff. Seventy-five patients underwent both sonography and arthrography. Compared with arthrography alone, ultrasound examinations enabled detection of 92% of rotator cuff tears (24 of 26 tears), with a specificity of 84% and a negative predictive value of 95%. Correlation was obtained in 30 of these patients who underwent surgery for rotator cuff tear or other soft-tissue abnormality. In this group, the sensitivity of sonography for detection of a tear was 93%, with a specificity of 73%, while for arthrography sensitivity was 87% and specificity was 100%. These data indicate that sonography is a useful, noninvasive screening procedure for patients suspected of having rotator cuff injury.     

Mammary intraepithelial neoplasia outgrowths (MINO): MINO and human ductal carcinoma <Emphasis Type="Italic">in situ</Emphasis>

Germ-line mutations in the BRCA1 tumour suppressor gene contribute to familial breast tumour formation, but there is no evidence for direct mutation of the BRCA1 gene in the sporadic form of the disease. In contrast, decreased expression of the BRCA1 gene has been shown to be common in sporadic tumours, and the magnitude of the decrease correlates with disease progression. BRCA1 expression is also tightly regulated during normal breast development. Determining how these developmental regulators of BRCA1 expression are co-opted during breast tumourigenesis could lead to a better understanding of sporadic breast cancer aetiology and the generation of novel therapeutic strategies aimed at preventing sporadic breast tumour progression.     

Influence of caloric restriction on the development of atherosclerosis in nonhuman primates: progress to date

Caloric restriction (CR) has been observed to retard aging processes and extend the maximum life span in rodents. In an effort to evaluate the effect of this nutritional intervention on physiologic variables in higher species, several nonhuman primate trials are ongoing. In particular, a study evaluating the independent effect of CR on the extent of atherosclerosis was initiated in 1993 in 32 adult cynomolgus monkeys. Therefore, the trial was designed to achieve identical cholesterol intake after animals were randomized to a control group or a calorie-restricted group (30% reduction from baseline caloric intake). The animals were routinely evaluated for glycated proteins, plasma insulin and glucose levels, insulin sensitivity, and specific measures for abdominal fat distribution by CT scans over a 4-year interval. The results from 4 years of intervention demonstrate that CR improves cardiovascular risk factors (such as visceral fat accumulation) and improves insulin sensitivity. In contrast to other primate studies with normolipidemic animals, CR had no independent effects on plasma lipid levels and composition in the presence of equivalent amounts of dietary cholesterol intake. Preliminary analysis of atherosclerotic lesion extent in the abdominal aorta has failed to demonstrate differences between control animals and CR animals. Follow- up studies are being conducted to determine the effect of CR on atherosclerosis extent in coronary and carotid arteries.      

Percutaneous drainage access: a simplified coaxial technique

We describe an access technique that we have used in 150 nephrostomy and biliary drainage procedures and for access to some abscesses and viscera. The system provides safe coaxial access with a 22-gauge removable hub needle, which then acts as a guide wire and is replaced by an 18-gauge cannula. A major advantage is that only one guide wire is used (0.038-inch) for the entire drainage procedure. No significant complications have occurred to date with this method.