Streptomycin and penicillin in combination proved effective in reducing the mortality of rats given lethal doses of radioactive phosphorus. Morbidity was also reduced and survival time prolonged.
Concern has recently been expressed with regard to the physiologic effects of primary intramedullary femoral nailing in seriously injured patients. "Damage control orthopaedics" techniques have been proposed, which comprise principally the use of primary external fixation. The aim of this study was to compare the physiologic effects of external femoral fixation with those of intramedullary stabilization over the first 24 hours after femoral fracture using an established large animal (ovine) trauma model.Under terminal anesthesia, bilateral high-energy femoral fractures and hypovolemic shock were produced using a pneumatic actuator. Twenty-four sheep were randomized into 4 groups and monitored for 24 hours. Group 1--control, group 2--trauma only, group 3--trauma and external fixation, and group 4--trauma and reamed intramedullary nailing. Outcome measures included the following: pulmonary embolic load (transesophageal echocardiography), metabolic base excess, plasma coagulation markers, and polymorphonuclear cell counts obtained from bronchoalveolar lavage samples.The total embolic load was significantly higher (P < 0.001) in the intramedullary nailing group. All trauma groups had a significant increase (P < 0.05) in prothrombin times with a fall in antithrombin III and fibrinogen levels. However, the type of fracture stabilization used did not significantly affect any of the other outcome measurements.A higher pulmonary embolic load can be expected during early intramedullary femoral fracture stabilization compared with primary external fixation. However, the degree of stimulation to systemic coagulation and pulmonary inflammation by each type of surgery was comparable.
A survey of the literature pertaining to several serial brain scanning procedures has been presented. These procedures include rapid brain imaging, sequential brain imaging, delayed from imaging, and follow-up brain imaging. Applications of these techniques to specific clinical problems have been stressed and the reported results reviewed. Thus, it has been indicated that rapid brain imaging is most useful in detecting lesions secondary to cerebrovascular disease but may also provide some helpful information pertaining to the differential diagnosis of other C.N.S. lesions demonstrated on subsequent static brain scans. Sequential brain imaging is a time-consuming adjunctive procedure which, however, can be extraordinarily helpful in a highly selected group of problem cases which present with relatively small lesions adjacent to normal anatomic structures which themselves have considerable radioactivity. Delayed brain imaging has the distinction of detecting the greatest number of intracranial lesions but is attended by tactical problems in maintaining an optimal patient flow through the department and also has the undesirable consequence of reduced information density and diminished image quality, unless greater radiation doses are injected. Follow-up brain imaging is useful in the differential diagnosis of cerebrovascular and neoplastic disease and in the assessment of effectiveness of radiation therapy.
In most of the previous radioisotope scanning studies on hepatic cirrhosis, attention has been directed primarily to the variation of the distribution of radioactivity, due to the decreased clearance of the radioactive material and the subsequent low counting rates (1, 4, 7, 9, 11, 13). It has been shown, however, that the usual mottled appearance of the radioisotope scan can be explained quite frequently by the statistical variation caused by the low counting rates (3), and thus such identification offers very little additional information over that which can be obtained by means of a simple clearance study. Studies on the clearance of both colloidal materials and substances selectively removed by the polygonal cells of the liver have demonstrated that both substances are cleared in a parallel fashion for varying degrees of hepatic involvement up to the point where a severe impairment of liver function is noted (5). Such generalized decreased clearances are consistent with the existence of arteriovenous shunts in the liver (10), which in turn indicate a decrease in effective liver blood flow, or flow perfusing the parenchyma so that reduced extraction of the materials, either by the reticuloendothelial or polygonal cells, occurs. If alterations of liver vascular flow of this nature are present, an increased radioisotope deposition would be seen in the areas of probable shunting (3). The object of the present investigation is to examine such shifts in the deposition of radioactive materials in patients with hepatic cirrhosis, and to correlate these shifts with the severity of disease and the clearance of colloidal gold. Methods Forty-six patients with a previous diagnosis of cirrhosis were selected for this study. A complete history was taken, with specific inquiries about duration, type, and amount of alcoholic intake, contact with hepatotoxins, previous symptoms of liver disease, significant other diseases, and food intake. In addition to a physical examination, the following laboratory tests were done in each case: Bromsulphalein retention (forty-five minutes), total proteins, albumin globulin with electrophoretic fractionation into alpha, beta, and gamma globulin, cephalin flocculation, thymol turbidity, alkaline phosphatase, direct and indirect reacting bilirubin, SGOT, aldolase, prothrombin time, and urine urobilinogen (Koch-Weser, Kilroy, et al., to be published). With consideration of all these data and without knowledge of the results of the radioisotope studies, each patient was classified clinically as exhibiting: (a) No significant decrease in hepatic function (10 patients) (b) Minimal decrease in hepatic function (13 patients) (c) Moderate decrease in hepatic function (13 patients) (d) Severe decrease in hepatic function (10 patients).
Progressive improvements in recording methods, collimation, data extraction technics, and the selection of materials with increased differential uptake have resulted in a growing acceptance of radioisotope scanning as a useful diagnostic method. In liver scanning, for example, Bender and Blau (1) and MacIntyre et al. in our institution (8) have demonstrated lesions as small as 2 cm. In brain scanning, both Cowan (2) and the Oak Ridge National Laboratory group (6) have identified lesions differing in counting rate by only 10 per cent from the surrounding tissue. In the light of these accomplishments it is of interest to ascertain the limits of the scintillation scanning method in its present state. Two major factors, instrumentation and the clinical correlation of the scan findings, must be considered. The first of these concerns the technics of determination of the spatial distribution of radioactive material within a region of the body and the presentation of the derived information in some manner understandable to the clinician. The second factor, clinical correlation, is concerned with the relationship between anatomical configuration and the portrayal of the radioisotope distribution. It must be remembered that organ structure itself is not visualized; only the variation in radioisotope distribution is measured, and from this the anatomic configuration may only be inferred. Statistics Inherent in scanning, as in all radioisotope procedures, is the uncertainty due to the random fluctuation of counting rate. Unfortunately, radioisotope scanning is particularly sensitive to such variation because the available information is scarce. This scarcity results from the high degree of collimation used, the short period of time spent on each area, and the radiation dose limitation. To illustrate the effects of random fluctuations, the following example may be cited: A scanner moving at a speed of 10 inches per minute will traverse a 1/2-inch distance in only three seconds. A counting rate of 1,200 counts per minute will then exhibit a probable error of plus or minus 9 per cent. With such parameters, by the definition of probable error, one-half of an area of homogeneous radioactivity would exhibit a variation of plus or minus 9 per cent in counting rate with a total range of 18 per cent, while the remainder of the area would exceed these limits. Obviously, if one attempts to see displacements in the magnitude of 10 per cent, visualization cannot be realized with such large random fluctuations. Confidence in identification would not be possible until the counting rate exceeds a minimum of 5,000 c/m or 250 counts recorded over the 1/2-inch site of interest (9). The so-called accentuation technics, such as that employed in photoscanning and in the counting rate cut-off method, can greatly increase the recognition of small counting rate changes but cannot aid in the reduction of random fluctuation.
SummaryData have been presented on the survival of the albino rat receiving radiation from internally administered P32 and colloidal Au198. These isotopes have been administered singly and in combination. The data clearly indicate that P32 and colloidal Au198 when administered in combination act synergistically in their killing effect. This appears to be related to the simultaneous injury of the reticuloendothelial system and the blood-forming tissues.
In the conventional rectilinear radioisotope scanning technics, the statistical averaging of data is in one dimension and is accomplished by the use of long ratemeter time-constants or by accumulation of a great number of counts. A two-dimensional integration has been accomplished through the use of a large photographic display area, quasi-Gaussian in light distribution, combined with very close lines-pacing. The photographic display dot contains approximately 10,000 points of light, each about one micron in diameter, arranged within a circle whose diameter approximates the 50 per cent contour line of the collimator. With the collimator selected, the diameter of the display dot has been from 1/2 to 1 inch. Total exposure is then accomplished by as many as 53 passages of the light beam, using line-spacing increments of 0.5 mm. The quasi-Gaussian distribution of light points in the display dot approximates the probability of detection of any one count, as shown by the collimator's isocount contour lines. Su...
Localization of 99mTc-Sn-polyphosphate in injured myocardium following experimental myocardial contusion in dogs has been demonstrated. Imaging using this radiopharmaceutical agent to detect areas of myocardial damage should be a useful technique in clarifying the difficult clinical diagnosis of myocardial contusion following closed chest trauma in man.
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