Biomedical subjects
Publications and source records attributed to B Kirchhof.
The typical CT visualisation of silicone implants and prostheses after ophthalmological operations to the eye and orbit are described. Changes following surgery or trauma, such as haemorrhage, inflammation or abscess, are discussed and the difficulties in differential diagnosis are dealt with.
Explore the source record for details and available documents.
Conventional analysis methods of prothrombin and thrombin are not able to measure thrombin generation and inhibition quantitatively and specifically, neither analyses of the interactions of plasmatic coagulation with vessel wall components and platelet substances are possible until now. Therefore, photometric and micro-coagulation methods have been developed for quantitative and specific analyses of thrombin generation and inhibition. The following reagents were used: plasma prothrombin, thrombin, which is generated in plasma, human factor Xa, human fibrinogen, a chromogenic substrate, phospholipids and calcium. To confirm the validity of the methodology various examples of application are demonstrated: the analysis of carboxylated and non-carboxylated prothrombin in human hepatic cells, the analysis of the thrombin generation and inhibition induced by endothelial cells and smooth muscle cells and the proof of a reduced platelet factor 3 availability in patients with various platelet aggregation defects.
The results of conventional venous thrombectomy performed in 37 patients with acute iliofemoral thrombosis were evaluated with special reference to early postoperative phlebography. In all patients thrombosis was verified preoperatively by angiography. No mortality was encountered, but the leg of one patient with phlegmasia coerulea dolens and advanced venous gangrene had to be amputated at the above-knee level. Four patients had pulmonary embolism in relation to surgery. Based upon postoperative phlebography, complete clearance of all obstructed segments was achieved in 5 patients only (13.5%), and subtotal or partial restoration resulted in 9 patients (24%). In 16 cases (43%) postoperative phlebograms appeared equivalent to the preoperative study, and in 7 cases (20%) additional vein segments were occluded. Despite the relatively high incidence of recurrent thrombosis, prompt relief of symptoms occurred in the great majority of patients. The more favorable angiographic results were obtained in the ilio-femoral segment; in contrast, new occlusions were predominantly found in the popliteal-crural segments. Restoration of a venous passage was not correlated with the duration of symptoms; in most instances, the removed clots appeared organized and adherent to the vein intima, even in patients with a short clinical history. With regard to probable etiological factors, somewhat better results were achieved for patients exposed to previous surgery or trauma and for patients with severe medical illness. In our view indications for venous thrombectomy should be rather restrictive; successful clearance and long-term patency can be expected mainly in patients with clots lying in the ilio-femoral segment surrounded by contrast medium in the distal portion.(ABSTRACT TRUNCATED AT 250 WORDS)
Four cases of unilateral or bilateral calcification of optic disk drusen have been observed on CT. The clinical indications are considered. The differential diagnosis of intra-orbital calcification is discussed.
In a phase I study the combination of AMSA and etoposide was applied to 12 patients with intensively pretreated, refractory AML to evaluate the basis for a subsequent phase II study in terms of drug dosage and timing. Each treatment cycle consisted in a 5-day regimen of AMSA 210 mg/m2/d days 2, 3 and 4. Etoposide was administered on days 1 and 5 with a constant loading dose of 100 mg/m2 by an 1-h infusion followed by a 23-h infusion, the dose of which was escalated in 3 steps from 110 mg/m2 to 200 mg/m2 and 230 mg/m2. In 18 treatment cycles the recommended dosage for a subsequent phase II study was found to be 660 mg/m2 etoposide per cycle together with 630 mg/m2 AMSA per course. Main side effects were nausea and vomiting as well as mucositis; 1 patient developed a severe intrahepatic cholestasis. In 11 from 16 evaluable treatment cycles a significant reduction of bone marrow blasts was observed with a mean cytoreduction rate of 0,26 log10/d. 4 patients, 3 of whom were primarily resistent to 2 TAD induction courses, achieved a partial remission.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
In contrast to earlier assays, the prothrombin determination described here uses a two-step reaction: first, prothrombin is activated with human factor Xa, phospholipids, Ca++ and factor V; second, the amount of activated prothrombin is assayed by the proteolysis of added fibrinogen. The assay is dependent only on prothrombin, and independent of other components of thrombin generation. Carboxy- and decarboxyprothrombin can be differentiated by means of using Echis carinatus venom instead of factor Xa as activator. The micro-coagulation assay is compared with a conventional one-stage coagulation test, with a prothrombin determination using chromogenic substrate and immunologically by Laurell electrophoresis.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Endothelial and smooth muscle cells cultured from minipig aorta were examined for their inhibitory activity on thrombin and for their thrombin generating capacity. Endothelial cells showed both a thrombin inhibition and an activation of prothrombin in the presence of Ca++, which was enhanced in the presence of phospholipids. Smooth muscle cells showed an activation of prothrombin but at a lower rate. Both coagulation and amidolytic micro-assays were suitable for studying the thrombin-vessel wall interaction.
Platelet factor 3 activity is usually determined by the Stypven method in which factor Xa generation is measured indirectly. The determination is dependent on factors I, II, V, X in the test sample. A coagulation assay for platelet factor 3, which measures the thrombin generation promoted by platelet factor 3, is presented. The test depends on platelet factor 3 only, because factors II, Xa, V, fibrinogen and Ca++ are added in excess. The usability of the new method is shown by platelet factor 3 determinations in patients with various platelet diseases, after ingestion of aspirin and in samples of platelet concentrates before and after storage.
Explore the source record for details and available documents.
Following ribosomal synthesis of the protein moiety of prothrombin, postribosomal carboxylation in the liver is necessary to obtain prothrombin ready for physiologic activation. Both decarboxyprothrombin and carboxyprothrombin can be determined by means of specific activators. Using synthetic substrates for thrombin, a micro-prothrombin assay suitable for functional determinations of decarboxy- and carboxy-prothrombin in liver biopsies was evolved. Decarboxyprothrombin was not found in plasma, independent of the kind of liver disease. Prothrombin determination in 31 liver samples showed no relation between the absolute concentration of carboxyprothrombin and decarboxyprothrombin and the kind of disease. The carboxyprothrombin fraction of total prothrombin was correlated with the activity of histologically estimated fibrosis in the liver.
Explore the source record for details and available documents.