Compartment pressure in association with closed tibial fractures. The relationship between tissue pressure, compartment, and the distance from the site of the fracture

We studied twenty-five consecutive patients who had a closed tibial fracture to determine whether there was a relationship between compartment pressure and the distance at which the pressure was measured from the site of the fracture. Tissue pressure was measured in all four compartments of the leg at the level of the fracture and at five-centimeter increments proximal and distal to the fracture. The peak pressure was usually found at the level of the fracture and was always located within five centimeters of the fracture. The highest pressures were recorded in the anterior and the deep posterior compartments in twenty patients, including all five of those who had had a fasciotomy. The measured pressure decreased steadily when sampled at increasing distances proximal and distal to the site of the highest recorded pressure. Decreases of twenty millimeters of mercury (2.67 kilopascals) five centimeters adjacent to the site of the peak pressure were common. Compartment syndrome was diagnosed in five patients on the basis of clinical findings, and the diagnosis was confirmed when peak compartment pressures of more than the critical threshold (within twenty millimeters of mercury [2.67 kilopascals] of the diastolic blood pressure) were recorded. Three of these five patients had measured pressures that were less than the critical threshold within five centimeters of the site of the peak pressure. Failure to measure tissue pressure within a few centimeters of the zone of peak pressure may result in a serious underestimation of the maximum compartment pressure. Our results suggest that measurements should be performed in both the anterior and the deep posterior compartments at the level of the fracture as well as at locations proximal and distal to the zone of the fracture to determine reliably the location of the highest tissue pressure in a lower extremity when a compartment syndrome is suspected clinically. The highest pressure should be used in the decision-making process.     

Improved surgical technique for the establishment of a murine model of aortic transplantation

The Scope of Professional Practice states that nurses may respond to the needs of patients by expanding their practice. Performing skin biopsies for cancer diagnosis is one such area. The provision of appropriate education, training and updating is essential. Clear guidelines for practice are required for all such procedures.     

Maxillary alveolar bone imaging. Wiener filter design

Optimal digital filter design is essential for noise suppression in the detection of subtle radiographic bony changes. The purpose of this study was to determine the signal (Ps) and noise (Pn) power spectra of sampled maxillary alveolar bone, to derive the optimal Wiener filter transfer function, H, from sets of Ps and Pn, and to quantify noise suppression through application of this filter. Sixteen standardized radiographs were made of five interproximal bony areas, each area from a separate dry human maxilla. The radiographs were digitized (0.02 mm/pixel resolution) and identical profiles (scan lines) generated between lead markers for each set of films. Ps was calculated from the averaged scan line of each set, Pn was calculated from the difference between the noisy images and the averaged scan line for each set, and an average maxillary H was calculated from the sets of Ps and Pn. Filtering of the 80 noisy sample radiographic profiles with H resulted in a 39% reduction in noise. Application of this digital filter should significantly improve detection of radiographic bony changes in the maxilla.     

Histologic perspective adds dimension to evaluating pocket measurements

The paper deals with the complex presentation of data for endoscopic studies on personal computers for the benefit of a physician in drawing up medical documents, establishing an accurate diagnosis, preparing a treatment regimen, as well as in facilitating his work, storing and processing data, searching for reference information, drawing up the dynamics of morbidity and its prediction. A scheme for complex presentation of the information required for endoscopic studies is given.     

Hepatocyte proliferation and gene expression induced by triiodothyronine in vivo and in vitro

Subcutaneous injections of hormone triiodothyronine in rats resulted in peak blood levels at 24 hr with return to baseline by 96 hr. The injections stimulated a liver regeneration response that resembled in timing and in magnitude of DNA synthesis (peak, 24 hr) that induced by 40% hepatic resection. The principal proliferation was of hepatocytes. Although there were some temporal differences from the gene expression of transforming growth factor-alpha, transforming growth factor-beta, and c-Ha-ras that are known to follow partial hepatectomy, the overall profile of these changes was similar to those after partial resection. The effect was liver specific and could be reproduced three times with no diminution in response in the same animal with injections at 10-day intervals. No response was detected in kidney or intestine. This effect in intact animals contrasted with the minimal ability of triiodothyronine to stimulate hepatocytes in culture. However, when the culture medium was enriched with epidermal growth factor, there was a dose-related response to triiodothyronine. The totality of these experiments provides a preliminary basis for the creation with pharmacological techniques of an in vivo hyperplastic hepatic condition permissive of transfection of new genes, as an alternative to partial hepatectomy. Although triiodothyronine was the test agent used, other hepatic growth factors singly or in combination could be candidates for this purpose.