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Biomedical subjects

C Busch

Publications and source records attributed to C Busch.

At least 181 records · Page 10Linked to original sources
PubMed1982

Identification in vitro of an endothelial cell surface cofactor for antithrombin III. Parallel studies with isolated perfused rat hearts and microcarrier cultures of bovine endothelium.

Two in vitro systems were used to identify an antithrombin III cofactor activity on vascular endothelium. Langendorff rat heart preparations or columns packed with endothelium cultured on microcarrier beads were perfused with mixtures of purified thrombin and antithrombin III. With each preparation, accelerated inhibition of thrombin by antithrombin III occurred during passage over endothelium. Platelet factor 4, protamine sulfate and diisopropylphosphoryl thrombin, all antagonists of the antithrombin III cofactor activity of heparin, significantly reduced the capacity of the preparation to inhibit thrombin. It is concluded that a substance with the functional properties of a stationary phase cofactor for antithrombin III is present on the microvascular endothelium and there catalyzes the inactivation of circulating free thrombin.

Animals↗
PubMed1982

Use of endothelium cultured on microcarriers as a model for the microcirculation.

The geometry of the vascular system is such that the surface area to volume ratio changes dramatically as a unit volume of blood circulates. Thus, it faces a surface area that is some 1000 times larger in the capillaries than in larger vessels. To approach the in vivo situation an in vitro model for the microcirculation was developed that uses endothelium cultured on microcarrier beads. Details of the culture method are presented. The cultures form confluent monolayers around the beads and resist removal by vigorous vortex mixing. Viability of the cells on the microcarrier is 100 per cent. The microcarrier cultures are packed into small columns (0.3 to 1.0 ml.) forming a perfusion system and used for studies of the binding of thrombin and platelet factor 4, for the demonstration of anticoagulant properties of the cells, for studies of the interaction between endothelium and platelets, and for the demonstration of prostacyclin release.

Animals↗
PubMed1981

Dipyridamole suppresses uptake of thymidine in human and bovine cells in vitro.

Dipyridamole has been shown to induce proliferative activity in heart muscle capillary wall cells in the rat. To test whether this effect is due to direct cellular stimulation we tested the substance in various in vitro systems (human lymphocytes, glial cells and endothelial cells; and bovine endothelial cells). During these conditions dipyridamole did not influence cellular proliferation. In all cell systems tested, uptake of labelled thymidine showed an inhibition by dipyridamole. This confirms the earlier finding that dipyridamole inhibits nucleoside uptake, and extends the finding to human cells.

Animals↗
PubMed1981

Microinvasive germ cell tumors of the testis.

We suggest that atypical germ cells in the seminiferous tubules of the testis and the testicular stroma without gross tumor be designated as microinvasive germ cell tumor of the testis. We report on 3 men who underwent orchiectomy for cryptorchid testes and diagnosis was microinvasive testicular germ cell tumor. One patient had an embryonal carcinomatous tumor and 2 had seminomatous tumors. No relapse was observed after more than 10, 28 and 59 months of followup, respectively.

Adult↗
PubMed1981

Lack of conformity in the behaviour of platelets during normal storage conditions at 22 degrees C.

Platelets prepared from citrate-phosphate-dextrose blood under normal routine conditions and concentrated to 1,000-1,600 x 10(9) x 1(-1) varied considerably in their capacity to acidify the medium. Serotonin uptake was well maintained for 5 days provided that adenosine 5'-triphosphate was within 50% of normal and pH was above 6.0. A strong release of platelet factor 4 was occasionally seen in relation to preparation. In some preparations the platelet factor 4 was well maintained for 5 days, in others a sudden or gradual release was seen during storage. The investigation indicates that differences in the quality of routinely prepared platelets occur during preparation and storage which are insufficiently well explained and controlled.

Adenosine Triphosphate↗
PubMed1981

Repair of cardiac defects with absorbable material.

Partial resection of the right atrium was performed in 5 young pigs. The defect was covered with a patch graft of absorbable material (polyglactin 910). Ten weeks postoperatively the mesh was completely replaced by a newly formed tissue with a smooth inner surface. Light microscopy showed regeneration of fibro-elastic tissue and the luminal surface was covered with endothelial-like cells indistinguishable from normal endocardium.

Animals↗
PubMed1980

Characterization of a platelet endoglycosidase degrading heparin-like polysaccharides.

An endoglycosidase (heparitinase) acting on heparin and heparan sulfate was partially purified (approximately 300 times) from human platelets by affinity chromatography on heparan sulfate substituted Sepharose. Only heparin-like polysaccharides were degraded by the enzyme. The susceptibility of various biosynthetic heparin intermediates indicated that the platelet heparitinase had a requirement for sulfamino but not ester sulfate groups. No activity toward other uronic acid containing glycosaminoglycans could be demonstrated. Glucuronidic but not glucosaminidic linkages in heparin or heparan sulfate were attacked by the enzyme as shown by analysis of the reducing sugar moiety in oligosaccharide products. The anticoagulant activity of heparin, determined in an antithrombin III activation assay, was markedly reduced after treatment with the heparitinase. The enzyme was released from its storage site in platelets after induction of the platelet release reaction. The physiological function of platelet heparitinase is not known but may be to modify extracellular heparin-like polysaccharides in the vascular system.

Blood Platelets↗
PubMed1980

[Structure of the esophagus of the dog].

The structure and arrangement of muscle fibres and vessels in various parts of the esophagus was investigated in 22 dogs using light and scanning electron microscopical techniques. The esophageal muscularis propria does not consist of outer longitudinal and inner circular fibres but of two layers of skeletal muscles forming apolar screw-like fascicles that run in opposite directions. Sphincter-like muscle fibre bundles in the upper cervical and abdominal part are closely connected with the tubular part of the esophagus. The present morphological findings indicate that the esophagus of the dog should not be considered to be a useful model for the elucidation of human esophageal malfunctions and their therapy.

Animals↗
PubMed1980

Absorbable material in vascular prostheses: a new device.

Seven to twenty cm long bypass grafts were inserted between the upper and lower part of the descending aorts of 20 young pids with end-to-side technique. The aorta between the anastomoses was closed by a ligature. As graft materials were used circular polyglactin 910 (Vicryl) mesh tubes (group I), external PTFE graft (Impra) and internal polyglactin mesh tube (group II), PTFE graft (group III) and external dacron mesh tube and internal polyglactin mesh tube (group IV). The biological process taking place in the grafted area was studied by light microscopy. The following observations were made: (1) The regenerative capacity of the pig aortic tissue permits 7 to 15 cm long polyglactin mesh grafts to be replaced by a new endothelialized vessel wall imitation. (2) When resorbable and non-resorbable materials were combined to form a composite graft (groups II and IV) the result proved to be a prosthesis with an internal covering of endothelialized arterial tissue.

Animals↗
PubMed1979

Surface properties of cultured endothelial cells.

Vascular endothelial cells (EC) are non-thrombogenic. The basis for this property is still essentially unknown. This paper summarizes our previous studies on EC associated glycosaminoglycans and on the specific binding of heparin to EC and describes the preventive effect of heparin sulphate (HS) on platelet adhesion to collagen; attempts to affect the binding of platelets to EC by specific removal of endogenous HS were, however, unsuccessful. The possible importance of EC surface HS for interactions with coagulation factors is discussed.

Aspirin↗
PubMed1979

Arterial regeneration following polyglactin 910 suture mesh grafting.

A suture mesh of polyglactin 910 [Vicryl (polyglactin 910) suture mesh] was placed as a patch graft into the thoracic aorta of 23 growing pigs. In three other pigs the mesh was grafted in the form of a tube to replace a short aortic defect. The biological processes taking place in the grafted area were studied by morphological methods. The following observations were made: (1) Hemostasis readily occurred by fibrin, platelet, and erythrocyte embedding of the mesh. (2) Early outgrowth of smooth muscle cells around the mesh took place from the normal aortic media and from a newly formed subintimal smooth muscle layer. (3) The newly formed arterial tissue was completely endothelialized within 20 days. (4) The polyglactin mesh had disappeared almost completely at 40 days, but the new wall seemed to retain sufficient strength throughout the observation time. (5) Only irregular deposition of elastic fibrils occurred, but in other respects the new tissue structurally resembled normal arterial tissue.

Animals↗
PubMed1977

Malignancy grading of epithelial bladder tumours. Reproducibility of grading and comparison between forceps biopsy, aspiration biopsy and exfoliative cytology.

107 bladder tumours cystoscopically suspected to be malignant were examined morphologically by forceps biopsy, aspiration biopsy and exfoliative cytology. The malignancy was graded from 0 through 4. The reproducibility of each method was established, and was found to be 80%, 65% and 90%, respectively. Exfoliative cytology underestimated the malignancy grade as compared with histopathology (59% of the malignant tumours were not jduged as malignant in the cytological grading), but showed no tendency towards overestimation and gave no falsely postiive diagnoses of malignancy. It is concluded that diagnosis of bladder tumours requires both biopsy and cytological techniques, since they proved complementary in a number of cases. Grading by aspiration biopsy is less reliable but may be of benefit in selected cases where forceps biopsy is less suitable.

Biopsy↗