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Biomedical subjects

A Thiede

Publications and source records attributed to A Thiede.

At least 289 records · Page 16Linked to original sources
PubMed1980

[Developmental and current status of clinical liver transplantation].

Liver transplantation is gradually beginning to move from the experimental to the clinical stage. Of the approx. 340 human "transplantation" which have been carried out worldwide, approx. 250 were performed by the transplantation teams in Denver and Cambridge. They were performed orthotopically. The detailed analysis of the indications by Calne ( n = 81) and Starzl (n = 153) is supplemented by analysis of the course of a total of 223 cases. Individual cases, such as a child with a liver transplant which is functioning for 9 1/2 years, show that liver transplantation is possible. Statistically, however, liver transplantation still involves a big question mark. Nevertheless, the Denver team has announced a 1 year survival quota of almost 50%. In the statistics on the causes of death, technical complications are clearly on the decline. The biliodigestive anastomosis constituted a "locus minoris resistentae", recently, however, the complication rate has been lowered considerably by the use of a Roux-Y-loop bypass and an intermediate gallbladder conduit. Infectious complications - bacterial, fungal and viral - caused or at least promoted by immunosuppression are a main problem. The special immunologic situation of the liver in transplantation has as yet not been clarified either experimentally or clinically. Unequivocal evidence of graft rejection is often difficult, because infectious and drug-induced liver intoxications can produce similar symptoms.

Biliary Tract Diseases↗
PubMed1980

[Action of cyclosporin A and cytimun on the survival time of accessory heart transplants (author's transl)].

The new immunosuppressive substances Cyclosporin A (group A = 15 mg) and Cytimun = ASTA 5122 (group B = 15 mg, group C = 5 mg) were tested in rats that received accessory cervical heart transplants. A syngeneic (DA leads to DA) and a strongly allogeneic (PVG leads to DA) strain combination served as controls of operative and immunogenetic parameters. Whereas Cyclosporin A (group A) brought about a local transplant tolerance in 90% of cases, at a dosage of 15 mg/kg per day (group B), Cytimun led in 88% of cases to lethal intoxication of the recipients. At a dosage of 5 mg/kg per day (group C), 67% of the animals survived; however, they showed electrocardiographic evidence of possible temporary rejection crises between the 5th and the 13th day.

Animals↗
PubMed1980

[Auto-suture stapler EEA in surgery of the colon and rectum [author's transl)].

The increasing use of auto-suture staplers for gastrointestinal anastomoses makes it necessary to test the value of this new method of suturing. In a "pilot study" the practicability, the tightness and permeability of the anastomosis and complications were tested and analysed in a total of 30 colon and rectal anastomoses using the EEA-suture gun. The results of 14 colon resections and 16 low anterior resections justify the further use of the EEA auto-suture apparatus and raise the question of a prospective controlled random study in which manual and mechanical machine sutured anastomoses are compared.

Colon↗
PubMed1979

[The effect of vasopressive drugs in managing bleedings from oesophageal varices and the intestinal tract (author's transl)].

The therapeutic effect of TGLVP a new hormonogen of vasopression in demonstrated in a pilot study: 9 patients suffering from bleeding oesophageal varices (in total 16) could be sufficiently treated by TGLVP, as well as 9 patients (in total 13) with abdominal haemorrhage of unknown aetiology and localization. Good results can be expected by TGLVP to bring gastrointestinal bleedings to a standstill.

Esophageal and Gastric Varices↗
PubMed1979

Comparison of the immunologic reactions of arterial transplants in the arterial system and of venous transplants in the venous system using inbred strains of rats.

(1) Arterial transplants used as arterial replacements induce sensitization of the recipient in the weakly as well as in the strongly allogeneic systems (afferent limb). (2) Venous transplants used as venous replacements induce sensitization of the recipient (afferent limb). (3) Arterial transplants show increasingly severe rejection reactions paralleling the degree of immunogenetic difference (efferent limb). (4) Veins transplanted as venous replacements are tolerated even in the strongly allogeneic systems (efferent limb).

Animals↗
PubMed1979

[In vivo investigations on suture reactions under sterile and not sterile conditions. Comparison of absorbable and nonabsorbable suture materials (author's transl)].

Suture materials from plant and animal substances are increasingly being replaced by synthetics. Among the nonabsorbable materials, synthetics are much superior regarding infection, threading and knot strength. A coating can improve management, which is currently more favourable with silk and cotton. Absorbable polyglycolic-acid sutures enable controlled reduction of thread breaking, but catgut sutures do not. Absorption is significantly accelerated by infections, while pH-fluctuation is less important. For infected tissue, monofile or pseudomonofile sutures are most suitable.

Absorption↗
PubMed1978

[Emergency colon diagnosis by water-soluble contrast enemas (author's transl)].

When surgery of the colon must be carried out for special indications and emergencies, it is not possible to make diagnosis with Ba SO4 contrast mediums. In these cases, reasonable success can be expected with substitution of three-iodized water-soluble contrast enemas. Through perforations and discharge from the colon they are absorbed into the free peritoneal cavity and enable diagnoses which are nearly comparable in quality to those done with Ba SO4 contrast mediums. In double contrast radiography according to the Malmö technique recognition of surface detail can be considered sufficient. Advantages and disadvantages as well as indications are listed in table form. Examples are documented to complete the chapter on results.

Adult↗
PubMed1978

Morphological reaction in transplanted small intestines using immunogenetically defined rat strain combinations.

From the inbred rat stains F344, LEW and Brown-Norway (BN), the following combinations were formed: syngeneic (LEW--LEW), weakly allogeneic (F344--LEW) and strongly allogeneic (BN--LEW). A small intestine segment was transplanted using the by-pass technique; after 10 days the graft was removed and histologically investigated. The strongest rejection was found in the lymphatic tissue and the epithelium of the small intestinal transplant. The immunogenetical difference is significant for the survival of the graft: the greater the immunogenetical difference between donor and host, the more severe the morphologically demonstrable rejection reaction.

Animals↗
PubMed1978

[Comparative immunological and morphological studies following transplantation of fresh and preserved allogeneic vein and artery segments in rat experiments].

Immunological and morphological investigations were carried out on immunogenetically different strain combinations of inbred rats following transplantation of fresh allogeneic and implantation of formalin preserved vein segments. In contrast to vital allogeneic transplants, which evoke an immunological response depending on immunogenetic difference between donor and recipient, there is neither humoral nor cellular immunological response after implantation of formalin fixed vein segments. Therefore, from an immunological standpoint, strongly allogeneic vein implants preserved by formalin can be used for replacement of arteries.

Animals↗
PubMed1978

[Xenogenic transplantation of aortic segments. Korrelated serological and histological investigations of the rejection mechanism].

With CDF inbred strain rats and randomly bred guinea pigs one syngenic control group and two xenogenic experimental groups were examined. The two xenogenic groups had different transplantation sites of aortic segments, the first of which was orthotoply retroperitoneal, the second heterotoply subcutanous. The following results were obtained: 1. A xenogenic vessel graft induces a massive production of antibodies after the fifth day, reaching a maximum on the 42nd day, and slowly and continuously decreasing thereafter. The tissue of the graft becomes acellular within 12 to 24h p.op. After 5 to 6 days an infiltrate appears, firstly dominated by granulocyts and monocyts and later by lymphocyts and plasmacells. Following the continuous destruction of the elastic fibres aneurysms grow. 2. The two xenogenic groups show that these two transplantation sites have no significance for the humoral response. 3. Both the progress of the antibodytiters (strong increase after the fifth day) after transplantation of aortic segments and the acute and chronical histologic changes suggest an immunological mechanism of hyperacute rejection.

Animals↗
PubMed1978

[Evaluation of the antigenicity of heart valve leaflets using inbred rat strain combinations (author's transl)].

Experiments with large, non-inbred animals yield no reliable evidence in the antigenicity of heart valves. With inbred strains of rats, however, it is possible to obtain evidence on the immunological reactions of heart valve leaflet transplants. Our experiments were undertaken on the inbred rat strains (CDR, LEW, CAP and BD5, using combinations as follows: syngeneic strain combination (CDF leads to CDF), weakly allogenic (RtH-1-identical) strain cimbination (LEW leads to CDF), strongly allogeneic (RtH-1-incompatible) strain combination (CAP leads to CDF). Strain BD5 was used for the control skin grafts. Either one or two heart valve leaflets were heterotopically intra-aortally transplanted. Sensitization was verified humorally by transplantation antibody titers and cellularly by subsequent donorspecific skin transplants. The following results were achieved: Allogeneic heart valve leaflets are antigenic. Intravascular grafting of one heart valve leaflet induces the same degree of sensitization as the grafting of two leaflets. In the RtH-1-identical system, sensitization is revealed only by subsequent skin grafting, whereas in the RtH-1-incompatible system, sensitization is humorally demonstrated as well. This indicates that in heart valve leaflet transplantation cellmediated reactivity is a more sensitive indicator than the humoral one. The greater the immunological difference is, the clearer the sensitization will be. In the strongly allogeneic system, the sensitization is even demonstrated humorally; skin grafts are rejected as "white grafts". Improved long-term results may be expected in allogeneic vital heart valve transplants if consideration is given to the HLA compatibility between donor and recipient; the appearance of delayed insufficiency could be greatly lessened or even deferred.

Animals↗
PubMed1978

Studies on the antigenicity of vital allogeneic valve leaflet transplants in immunogenetically controlled strain combinations.

The use of defined inbred strains of rats enables reproducible experimentation on the antigenicity of heart valve leaflet transplantation. The inbred strains CAP, F344, and LEW were used as syngeneic, weakly allogeneic (RT-1-identical) and strongly allogeneic (RT-1-incompatible) strain combinations. After heart valve leaflet transplantation, humoral and cell-mediated immune responses were investigated. The results were: (1) Allogeneic heart valve leaflets are antigenic. (2) Just one heart valve leaflet, applied intravascularly induces sensitization of the recipient. (3) In the weakly allogeneic system, sensitization is only revealed by donor-specific skin transplants, while in the strongly allogeneic group, sensitization is demonstrated humorally as well. (4) The greater the immunogenetical difference, the sooner sensitization appears. In the strongly allogeneic system, skin transplants were rejected as "white grafts".

Animals↗
PubMed1978

[Current aspects in the endothelialization of artificial prostheses (experimental studies in rats)].

The interaction between the blood and the inner prosthetic wall after grafting with the autoalloplastic SPARKS prostheses was examined by light and electron microscopy as well as by autoradiography. The results indicate that intercellular bridges are missing, and therefore that those cells that line the inner surface of the prosthesis are no real endothelial cells, as observed with the electron microscope. The authoradiographic findings demonstrate that blood monocytes definitely contribute to the construction of the new inner surface. We showed that although there is a possibility of transformation, the results is not a real endothelial cell, as shown by electron microscope. Nevertheless this cell apparently can fulfil its function.

Animals↗