Comparison of blood flow and histological changes in rat models of testicular ischemia.

PURPOSE: Our aim was to quantify objectively the degree of vascular insufficiency produced by twisting versus clamping the spermatic cord, and determine the contribution of the vasal vessels to these changes using the laser Doppler flowmeter. MATERIALS AND METHODS: Three groups of 12 male Sprague-Dawley rats each were studied. Group 1 underwent 720-degree torsion of the spermatic cord, group 2 underwent vascular clamping of the spermatic cord with 1 clamp, excluding the anatomically separate vasal vessels, and group 3 underwent vascular clamping of the entire spermatic cord and vasal vessels with 2 clamps. Blood flow and histological changes were determined. RESULTS: Vascular clamping of the spermatic cord in groups 2 and 3 resulted in a significant decrease in testicular blood flow compared to 720-degree torsion (p < 0.05). These flow changes correlated with more severe and reproducible gross changes, and histological features of seminiferous tubule degeneration compared to spermatic cord twisting. CONCLUSIONS: In the rat clamping the spermatic cord is a more severe and reproducible model of testicular torsion than 720-degree torsion. The contribution of the vasal vessels to the decrease in blood flow and resulting histological degeneration after testicular ischemia is negligible in the rat.

A platelet activating factor antagonist attenuates the effects of testicular ischemia.

PURPOSE: Platelet activating factor, a biochemical marker and lipid mediator of ischemic injury, has been demonstrated in several organ systems. The objective of this study was to investigate the possible role of platelet activating factor in testicular ischemic injury. MATERIALS AND METHODS: Five groups of 6 male Sprague-Dawley rats were studied, including group 1-nonoperated controls, group 2-sham operated controls, group 3-those that underwent administration of 10 micrograms./kg. exogenous platelet activating factor into the left testicular artery, group 4-those that underwent 4 hours of testicular ischemia and group 5-those that received pretreatment with 0.4 mg./kg. of the platelet activating factor antagonist CV-6209 intravenously before 4 hours of testicular ischemia. Ipsilateral and contralateral testes were examined histologically and seminiferous tubular diameters were measured. RESULTS: Exogenous platelet activating factor administration in group 3 and 4 hours of ischemia in group 4 resulted in a similar extent of histological degeneration of the experimental testicle. Pretreatment with CV-6209 in group 5 resulted in a marked decrease in hemorrhagic discoloration, vascular congestion and histological changes noted with ischemia in group 4. CONCLUSIONS: The results of this study suggest that platelet activating factor has a biochemical role in tissue injury associated with testicular ischemia. Also, administration of a platelet activating factor antagonist before the ischemic event decreases seminiferous tubule degeneration.

Intra-abdominal abscess in the 1980s.

Prompt recognition, early localization, and adequate drainage have contributed to the decreased morbidity and mortality rates associated with intra-abdominal abscess in the last decade. The physical examination, ultrasonography, computed tomography, and radionuclide scans provide information that leads to early detection and localization of abscess in almost all patients. Percutaneous drainage should be the initial procedure unless specific indications for surgery exist.

Acute, complete, extrinsic obstruction of the Björk-Shiley valve in the immediate postoperative period.

The following report describes a case in which acute, complete, extrinsic obstruction of a Björk-Shiley prosthetic aortic valve by suture material occurred in the immediate postoperative period.

Postoperative monitoring of myocardial oxygen tension: experience in 51 coronary artery bypass patients.

Following a preliminary feasibility report, polarographic monitoring of myocardial tissue O2 tension (Pmo2) in 51 coronary bypass patients has been accomplished. In this context, the influence of rapid atrial pacing (RAP), O2 inhalation, and intra-aortic balloon assistance (IAB) was statistically analyzed using Wilcoxon sign-rank and Student's t-tests. Electrodes were implanted in revascularized and nonrevascularized areas for comparison (24.0 +/- 1.1; and 26.3 +/- 1.8 mmHg Pmo2, p, not significant). Increasing myocardial O2 demand with RAP caused a 6% PmO2 drop (p less than 0.01). A 70% O2 inhalation increased Pmo2 by 30% (p less than 0.01). In 5 cases the benefit of IAB was confirmed by a 41% increase in Pmo2 (p = 0.02). These data support the clinical usefulness of polarographic Pmo2 as a measure of regional myocardial oxygenation. In addition to early recognition of intraoperative or postoperative graft failure previously reported, the efficacy of various therapeutic interventions can be more precisely determined.

Monitoring regional myocardial function after myocardial revascularization.

A system using only small platinum electrodes for monitoring intramyocardial polarographic oxygen tension (MP02), electrograms (ECG), and impedance-derived wall motion (WM) was experimentally tested and clinically implemented. In nine open-chest, anesthetized dogs. two platinum electrodes were inserted along the subepicardial direction of the muscle fibers. As verified by cinefluoroscopy, WM corresponded to changes in distance between the platinum electrodes (r = 0.91 +/- 0.02). The system responded to a 10 minute occlusion of the left anterior descending coronary artery (LAD) as follows: Dyskinetic WM appeared in 10 seconds (p less than 0.05); MP02 decreased (26.4 +/- 1.8 to 14.8 +/= 1.9 mm Hg, p less than 0.05) in 1 minute; ST segments increased (4.8 +/- 1.5 to 12.3 +/- 3.1 mV, p less than 0.05) in 3 minutes. On reperfusion, WM, ST segments, and MP02 normalized in 15 seconds, 30 seconds, and 1 minute, respectively. Hence, ischemia affects WM more acutely than either ECG or MP02. In five patients, ischemic changes before coronary bypass were reversed over 5 days: MP02 (17.4 +/-; 1.9 to 19.6 +/-1.7 mm Hg), ST segment (2.2 +/- 6 to 1.0 +/- 0.4 mV), and WM returned to normal. Thus a system has been designed which simultaneously monitors regional WM, MP02, and ECG. The method has proved to be a sensitive and practical approach for assessing perioperative myocardial function.