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Biomedical subjects

P Tracey

Publications and source records attributed to P Tracey.

8 recordsLinked to original sources
PubMed1984

Computed tomographic analysis of renal calculi.

An in vitro study sought to determine the feasibility of using computed tomography (CT) to analyze the chemical composition of renal calculi and thus aid in selecting the best treatment method. Sixty-three coded calculi were scanned in a water bath. Region-of-interest measurements provided the mean, standard deviation, and minimum and maximum pixel values for each stone. These parameters were correlated with aspects of the stones' chemical composition. A multivariate analysis showed that the mean and standard deviation of the stones' pixel values were the best CT parameters for differentiating types of renal calculi. By using computerized mapping techniques, uric acid calculi could be perfectly differentiated from struvite and calcium oxalate calculi. The latter two types also were differentiable, but to a lesser extent. CT has a potential role as an adjunct to clinical and laboratory methods for determining the chemical composition of renal calculi in an effort to select optimal treatment.

Calcium Oxalate↗
PubMed1983

Digital nephropyelography following intravenous renal digital subtraction angiography.

A 14-inch image intensifier designed for digital radiography has made feasible adjunctive evaluation of the renal parenchyma and collecting structures following intravenous digital subtraction angiography (DSA). Initial experiments with rabbits showed digital nephrography to be superior to film-based nephrotomography in terms of renal conspicuity and imaging flexibility. Preliminary experience with 30 patients undergoing DSA reaffirms the suitability of this method for the evaluation of renal anatomy and function. Only about half the amount of contrast material needed for conventional excretory urography is required.

Angiography↗
PubMedDate not supplied

CT determination of renal and hepatic microvascular volumes in experimental acute renal failure.

Alterations in renal blood flow are considered to play an important role in the pathogenesis of acute renal failure. Most techniques designed to assess organ blood flow and microcirculatory disturbances are relatively invasive and cumbersome. This study describes a noninvasive method for the determination of an organ's fractional vascular volume (FVV)-the fraction of an organ occupied by blood vessel lumen. It utilizes computed tomographic (CT) scanning and a contrast agent, perfluoroctylbromide (PFOB), which remains intravascular and is not excreted by the kidney. Acute renal failure (ARF) was induced in rats by intraperitoneal injection of glycerol (5 g/kg). CT scans of kidneys, liver, and heart were performed prior to and following intravenous administration of PFOB. FVV of kidney and liver were calculated prior to induction of ARF and at selected time periods following ARF (20-50 minutes and 60-120 minutes). FVV of the kidney decreased significantly 20-50 minutes following ARF and had returned to control values at 60-120 minutes. Renal histologic abnormalities were more severe at the later time period. Thus, early alterations in blood flow precede pathologic abnormalities in the kidney following glycerol-induced ARF. Determination of an organ's fractional vascular volume is a simple noninvasive technique which provides useful information on the microcirculation during the course of experimental disease.

Acute Kidney Injury↗
PubMedDate not supplied

Comparative microangiographic studies of glycerol- and mercuric chloride-induced acute renal failure in rats.

Microcirculatory abnormalities may be important in the genesis and/or maintenance of acute renal failure. This work describes the functional, microangiographic, and histopathologic alterations in two experimental models of acute renal failure. Glycerol and mercuric chloride (HgCl2) administration to dehydrated rats produced acute renal failure characterized by a similar degree of renal dysfunction at 24 hours and almost complete functional recovery at one week. Both toxins were associated with early (1/2-1 hour) microangiographically determined perfusion alterations, but in the rats given glycerol, a return to near normal appearance was noted at 2 to 6 hours. Subsequent studies did show mild to moderate residual changes at one week. In contrast, HgCl2 treatment was associated with progressive microcirculatory abnormalities that correlated in part with residual histopathologic alterations. These studies emphasize the discrepancy between functional, circulatory, and pathologic abnormalities in experimental acute renal failure and may improve our understanding of this complex disorder.

Acute Kidney Injury↗
PubMedDate not supplied

A creative clinical education model: three views.

To effectively educate nurses who are able to meet changing health care needs, new models for clinical experiences must be considered. Collaborative arrangements between practice and education are particularly useful. The preceptor approach is used widely for seasoned students in senior experiences nearing graduation. The "paired" model, a variation on the preceptor model, has worked well in one setting for beginning students. It needs to be tried in other settings with different faculty and perhaps in other types of courses, and it needs to be tested. Collaboration between education and practice not only benefits education, but lays the groundwork for shared scholarly endeavors. Ultimately these relationships have a positive impact on patient care.

Anxiety↗