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Biomedical subjects

W Mergner

Publications and source records attributed to W Mergner.

16 recordsLinked to original sources

Torulopsis glabrata fungemia as a complication of a clotted transjugular intrahepatic portosystemic shunt.

Torulopsis glabrata fungemia developed in a patient with a clotted transjugular intrahepatic portosystemic shunt (TIPS) 11 months after placement. Fungemia persisted despite treatment with amphotericin B. On autopsy, T. glabrata was found in the thrombus occluding the TIPS and extending into the splenic and portal vein. TIPS infections may be considered in patients with fungemia.

Candidiasis↗

Pretreatment with an inhibitor of mac-1 alters regional and systemic platelet function during ischemia-reperfusion in swine.

Myocardial ischemia-reperfusion alters regional and systemic platelet function. The aim of our study was to elucidate the role of the Mac-1 receptor in changes of platelet function by using the leumedin, NPC-15669, an inhibitor of Mac-1 upregulation. In an open-chest swine model (n = 15), the treatment group (n = 6) received NPC-15669 (10 mg/kg loading dose over 12 min at the rate of 5 ml/min at the onset of left-anterior descending coronary artery occlusion, followed by constant infusion at 6 mg kg-1 h-1 during 90 min of reperfusion). Regional platelet aggregation (response to 5 microM ADP) increased after 15 min occlusion (126% of baseline) and at 90 min of reperfusion (156% of baseline). This increase in platelet aggregability was inhibited by NPC-15669 (83% of baseline after 15 min occlusion and 98% of baseline at 90 min reperfusion, both p < 0.001 compared to control). Systemic platelet function was not affected by NPC-15669 after 15 min occlusion (102% of baseline vs. 96% of baseline for control, p = NS). At 90 min of reperfusion platelet function was increased in controls (131% of baseline) and not affected by NPC-15669 (126% of baseline, p = NS). Myocardial neutrophil accumulation did not differ between the control and treatment groups. Inhibition of Mac-1 upregulation by NPC-15669 attenuates the increased regional platelet aggregability resulting from myocardial ischemia-reperfusion, with a less marked effect on the systemic response. The data suggest that Mac-1 may modulate regional platelet responses induced by ischemia-reperfusion. The increased aggregability of platelets during ischemia and reperfusion and its attenuation by inhibition of Mac-1 may be relevant for future strategies to reduce coronary arterial occlusion by platelet thrombi.

Analysis of Variance↗

A canine model of acute coronary artery thrombosis for the evaluation of reperfusion strategies.

A model of coronary artery thrombosis which: (1) provides a stable thrombus; (2) incorporates intimal injury; (3) has a low mortality rate; (4) responds predictably to thrombolytic therapy, and (5) is technically simple, was developed. Intimal injury was produced proximal to a critical stenosis and followed by the infusion of a blood and thrombin mixture into the injured segment. After thrombus formation flow remained absent in all control animals (n = 7). Microscopy showed intimal injury and coronary thrombosis with platelets adherent to the subendothelium. In animals treated with tissue plasminogen activator (n = 7) flow returned to > 60% of baseline at 20.2 +/- 7.7 min and was cyclical. Mortality and complications were infrequent. This model is useful in investigations of reperfusion therapy.

Animals↗

DNA analysis of cardiac myxomas: flow cytometry and image analysis.

Cardiac myxoma is the most common primary tumor of heart, but there is a longstanding controversy over whether it is a true neoplasm or a reactive lesion. We analyzed 24 cardiac myxomas from 22 patients: 22 by DNA flow cytometry and five by image analysis. Two myxomas were aneuploid; one of those analyzed by flow cytometry, and the other by image analysis. Proliferative fractions (S + G2/M) were high in three tumors from patients with multiple myxomas (mean, 15.9%; SD, 4.0%) as compared with 12 solitary uncomplicated myxomas (mean, 7.7%; SD, 6.0%). S-phase and proliferative fractions were low in embolic, recurrent, and solitary myxomas. The presence of aneuploidy in some myxomas supports a neoplastic origin for this tumor.

Adult↗

Myocardial protection by perfluorochemical infusion during transient ischemia produced by balloon coronary occlusion.

To assess the efficacy of the perfluorochemical Fluosol-DA 20% for myocardial protection during repeated periods of balloon occlusion of the left circumflex coronary artery, 25 anesthetized dogs were randomized to receive either oxygenated perfluorochemical, (Fluosol-DA [F]; n = 10) or oxygenated Ringer's lactate (R; n = 6), at the rate of 30 ml/min, during inflation of the balloon. A control group (C; n = 9) received no infusion. A total of eight inflations were performed, each lasting 90 seconds, followed by an equivalent deflation time. Hemodynamics, ECGs, regional myocardial function, and biochemical parameters were studied. Significant differences were noted in ST segment elevation at 90 seconds of inflation in the F (1.5 mm +/- 0.6), C (3.7 mm +/- 0.75), and R (2.9 mm +/- 0.75) groups (F vs C or R p less than 0.05). This was associated with significant improvement in radial shortening in the jeopardized zone at 45 seconds into occlusion in the F group compared to the C and R groups (F = 21.1% +/- 5.1 vs C = 3.5% +/- 4.5 or R = 1.1% +/- 3.2; p less than 0.05). Results of electron microscopy showed reversible changes of ischemia within the mitochondria, and these were most marked in the C and R groups compared to the F group. Endothelial swelling was mild and was present only focally in the R and C groups. Thus perfluorochemicals may enhance the safety and efficacy of balloon angioplasty.

Adenine Nucleotides↗

Diffuse alveolar hemorrhage temporally related to cocaine smoking.

Previous reports of respiratory complications from cocaine abuse have focused on pulmonary barotrauma or a reduction in carbon monoxide diffusing capacity. We report a patient who developed life-threatening alveolar hemorrhage following repeated inhalation of alkaloid cocaine.

Adult↗

Unbuffered osmium staining of cell organelles: alterations induced by cell injury.

We have studied the localization of osmium reduction products to investigate the functional state of organelles as well as organelle interrelationships during cell injury. In normal hepatocytes osmium deposits of variable intensity are seen in nuclear envelope, endoplasmic reticulum. Golgi cisternae and vesicles and lysosomes. Buffering of osmium with s- collidine (pH 7.4) prevents the deposition of osmium. Reversible (30 min) and irreversible (60 min) ischemia without reflow causes no change in the pattern of osmium deposition. Irreversible ischemia followed by reflow causes decreased staining of endoplasmic reticulum (ER) and redistribution of the osmium deposits through the cytoplasm. Reversibly injured pancreatic acinar cells in cultured explants manifest a similar loss of osmium staining in the endoplasmic reticulum cisternae. The administration of antimicrotubule drugs induces an accentuation of osmium staining in localized cisternal elements of hepatocytes. These heavily stained cisternae appear to give rise to the bounding membranes of drug-induced autophagic vacuoles. Cytoplasmic organelles sequestered inside the autophagic vacuoles acquire intense staining when they begin to undergo degradation. In homogenized liver tissue all the subcellular organelles show osmium deposits. The deposits are preferentially localized along the organelle membranes. In particular the dense deposits in the ER lumen are not seen in the subcellular fractions. Phospholipase A2 (3 units/mg protein) enhances the deposition of osmium in the lumen of microsomal vesicles, whereas the presence of detergent has no such effect. Addition of EDTA to the homogenizing medium enhances the ultrastructural preservation of the subcellular fractions but has little effect on the deposition of osmium. OsO4 deposition occurs at acid pH and the intensity and pattern of the stain can be modified in vivo and in vitro. Osmium tetroxide deposition is induced at sites of membrane transformation (autophagic vacuoles) and degradation (lysosomes). Calcium influx and phospholipase activation (ischemia, tissue homogenization, phospholipase addition) enhance osmium deposition and/or influence the localization of the staining pattern.

Animals↗

Aspergillus vegetative endocarditis and complete heart block in a patient with acute leukemia.

Aspergillus flavus vegetative endocarditis together with myocardial abscesses and pneumonitis developed in a patient with acute lymphocytic leukemia. The initial diagnosis was not suspected until 67gallium imaging revealed a radiographically undetectable thoracic abnormality. Despite apparently "early" diagnosis, antifungal therapy was inadequate to prevent disruption of the bundle of His, complete heart block and death.

Aspergillosis↗