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Biomedical subjects

A Thiede

Publications and source records attributed to A Thiede.

At least 91 records · Page 5Linked to original sources
PubMed2000

[Aorto-mesenteric artery compression syndrome].

INTRODUCTION: The aim of this paper was to describe a rare gastrointestinal motility disorder caused by vascular compression of the duodenum. PATIENTS: The authors present two patients with vomiting and severe weight loss. Diagnostic evaluation revealed superior mesenteric artery syndrome. METHODS: After frustrane treatment with i.v. infusions, surgical intervention with laterolateral duodenojejunostomy or Roux-en-y reconstruction for restoration of the intestinal passage was performed. RESULTS: Following initial recovery, the first patient showed permanent anorexia. Psychosocial evaluation revealed a severe pathological mother-child relationship. Intensive psychological treatment finally achieved definite weight gain and complete recovery in this patient. The second case subsequently gained weight without psychological evaluation. CONCLUSION: The authors review the literature, pointing out the anatomy of the duodenojejunal angle, the etiology, and the predisposing factors, as well as diagnostic and therapeutic strategies.

Adolescent↗
PubMed2000

Donor-derived alloantigen-presenting cells persist in the liver allograft during tolerance induction.

The predictive value of chimerism was evaluated in three different transplantation models in the rat without immunosuppression: small bowel- (SBTx), liver- (LTx), and liver/small bowel transplantation (LSBTx) were performed in the Brown Norway (BN)-to-Lewis-(LEW) strain combination. Immunohistochemistry and flow cytometry were used to identify donor cells in the recipient's spleen. Their number did not change significantly during transient rejection or tolerance after LTx and LSBTx. However, the amount of donor-derived nonparenchymal cells within the liver allograft including antigen-presenting cells (APCs), such as dendritic and Kupffer cells, clearly mirrored the recipient's immune status: as expected, their number decreased during rejection, but recovered considerably during and after tolerance induction. We conclude that donor cells in the periphery of the recipient correlate with the presence of the allograft, but do not seem to influence graft acceptance actively. However, the kinetics of the detected donor APC population in the liver suggests their important role in modifying the recipient's immune response towards tolerance.

Animals↗
PubMed2000

"Tolerogenic effect" of the liver for a small bowel allograft.

A newly developed liver/small bowel transplantation model (LSBTx) was used to investigate the tolerogenic effect of a liver allograft toward a simultaneously transplanted small bowel. Small bowel transplantation (SBTx) under high-dose immunosuppression was compared to LSBTx with a lower FK506 dosage. Syngeneic Lewis [(LEW) to LEW] and two fully allogeneic rat strain combinations (Brown Norway-to-LEW and Dark Agouti-to-LEW) were used. Clinical course and histological findings after SBTx demonstrated a chronic rejection of the small bowel allograft within 100 days. However, after LSBTx long-term acceptance (> 150 days) was achieved after a transient rejection crisis, although initial immunosuppression was significantly lower. Furthermore, indicator heart transplantations demonstrated the induction of donor-specific tolerance in both allogeneic strain combinations. In contrast to other LSBTx rat models, these results reflect observations after human LSBTx, in which the rate of acute and chronic rejection is also significantly lower than after human SBTx.

Acute Disease↗
PubMed2000

Analysis of cellular events in hepatic allografts: donor progenitors induce intragraft chimerism.

Long-term graft acceptance and tolerance induction after allogeneic rat liver transplantation are well described. However, the underlying mechanisms remain unclear. In this study we investigated the cellular events within the liver graft during initial immunosuppression and long-term acceptance. Orthotopic liver transplantation was performed in the Dark Agouti (DA)-to-Lewis (LEW) and LEW-to-DA rat strain combination. In order to achieve long-term acceptance, LEW recipients of DA livers were treated with two different short-term therapies. Non-parenchymal cells (NPC) were isolated from liver allografts on days + 10 and + 100 after transplantation and donor-specific leukocytes were immunophenotyped by flow cytometry. Both the monotherapy and triple therapy prolonged graft survival (> 100 days). Liver allografts from LEW donors into DA recipients were spontaneously accepted across a complete MHC mismatch without immunosuppression. Liver allograft rejection was induced by infiltrating alloreactive immunocompetent cells. But the intensities of cell infiltration in the early and late phases after transplantation did not correlate with eventual outcome. Donor-specific NPC decreased to 18-25% on day + 10 in both therapeutic groups, but had rebounded to up to 40% by day + 100. Recurrence of donor-specific cells was caused almost exclusively by rising T cell counts. The persistence of dendritic cells in the late phase after transplantation could be clearly demonstrated. Repopulation by donor-specific T lymphocytes was observed in long-term accepted liver grafts. This recurrence may be based on the differentiation of liver-derived progenitor cells. The persistent coexistence of donor and recipient cells within the liver allograft (intrahepatic chimerism) appears to be characteristic and may be important for long-term acceptance.

Animals↗
PubMed2000

Long-term small bowel allograft function induced by short-term FK 506 application is associated with split tolerance.

Functional long-term allograft survival after experimental small bowel transplantation (SBT) is limited by chronic rejection. Initial application of high-dose FK 506 has been shown to induce stable long-term graft function. In order to examine whether this long-term function is associated with donor-specific tolerance, we analyzed the functional status of recipient T cells in vivo and in vitro. One-step orthotopic SBT was performed in the allogeneic Brown Norway (BN)-to-Lewis rat strain combination. FK 506 was given daily at a dose of 2 mg/kg from days 0-5 in the rejection model and from days 0-9 in the long-term functional model. Mean survival time in the rejection model was 98 +/- 2.8 days. Histological examination of these small bowel allografts disclosed signs of chronic rejection. In contrast, all animals of the long-term functional model survived long term (> 250 days) without clinical signs of chronic rejection. The latter model, furthermore, produced evidence of donor-specific tolerance. Whereas heterotopic Dark Agouti (DA) hearts were rejected regularly within 7 days, BN hearts survived indefinitely (> 70 days). In vitro, mixed leukocyte reactivity of CD4+ T cells was similarly strong against donor (BN) antigens as against third-party (DA) antigens. The split tolerance revealed by our in vivo and in vitro results enabled acceptance of both the small bowel allograft without signs of chronic rejection and of donor-specific heart allografts.

Animals↗
PubMed2000

Comparison of anastomotic microcirculation in coloanal J-pouches versus straight and side-to-end coloanal reconstruction: an experimental study in the pig.

Several studies have shown a lower rate of anastomotic leakages in patients with coloanal J-pouch reconstruction than in those with straight coloanal anastomosis following anterior resection of the rectum. This study investigated whether this difference is due to a better anastomotic microcirculation. Thirty-two healthy, adult Göttinger mini-pigs underwent anterior rectal resection. They were subsequently randomized to following four groups (eight pigs per group): straight end-to-end, side-to-end, small pouch (4 cm), and large pouch (8 cm) coloanal anastomosis. Bowel perfusion was measured before and after vessel ligature at predefined locations using laser Doppler flowmetry. After completion of the anastomosis microcirculation was investigated 1 cm above, below, and directly at the anastomotic site. Following vessel ligature there was a 25% drop in blood flow. After completion of the anastomosis there was a further decrease of 25% in the distal segment, while no changes were observed above the anastomosis. There were no statistical differences either before or after completion of the anastomosis between the various groups. It is concluded that anastomotic blood flow does not depend on the type of coloanal reconstruction in healthy pigs.

Anastomosis, Surgical↗
PubMed2000

Laparoscopic fundoplication--short- and long-term outcome.

Gastroesophageal reflux disease is probably the most frequently occurring benign functional disorder in the Western industrial countries. With the increasing popularity of laparoscopic anti-reflux procedures, issues on the appropriate technique have been revitalized. The purpose of this study is to evaluate the short- and long-term outcomes of laparoscopic fundoplication and reflect on the perspective of an increasing frequency of performed operations. The data sampling is based on a literature review and a questionnaire. It can be summarized that reflux recurrence due to breakdown of the wrap or herniation of the wrap can also develop in later years after the primary surgery and amount up to 8%. Persistent dysphagia is a severe problem in the first post-operative year, but usually decreases with time and is limited to rates of 3-5% on the long-term follow-up. Other functional problems, such as gasbloat, meteorism and epigastric pain--the cause often cannot be further detected or specified--limit the quality of life of patients after laparoscopic anti-reflux surgery in the long-term follow-up in up to 5% of cases. Side effects of laparoscopic antireflux procedures can be limited to 5 to 10%, but not totally avoided.

Chronic Disease↗
PubMed2000

Bacterial population of chronic crural ulcers: is there a difference between the diabetic, the venous, and the arterial ulcer?

BACKGROUND: At the Surgical Department of Surgery of the University Hospital Würzburg microbiological examinations were performed of the ulcer grounds from patients with diabetic-neuropathic, diabetic-ischemic, venous, and arterial leg ulcers. The aim of the examination was to evaluate possible differences in the healing process of these ulcers based on the knowledge of their bacterial populations. PATIENTS AND METHODS: In a period of four months, 63 patients were consecutively examined by taking a bacteriological swab of their ulcer area. The healing process of their wounds was followed and related to the impact of bacterial colonisation and clinical signs of infection. RESULTS: 95% of the venous and arterial leg ulcers had a positive smear, whereas only 70% of diabetic ulcers were positive for bacterial growth. Bacterial population of the three ulcer entities, however did not differ significantly. 100% of the clinically infected venous and arterial ulcers but only 80% of the diabetic wounds revealed a positive smear. On the other hand, only 22% of the venous ulcers with a positive smear developed a clinical infection in contrast to 70% of the arterial and diabetic. Venous ulcers showed only in a few patients prolonged healing, even in cases of marked bacterial contamination. Despite of clinical signs of infection however, diabetic wounds sometimes did not reveal a positive wound smear (20%). All infected venous, but only 20% of the infected ischemic ulcers healed satisfactorily. Arterial wounds with no bacterial growth healed significantly better than contaminated wounds. This difference was not significant in the other entities. Radical removal of the infection by minor amputation increased the healing rate in diabetic ulcers over 80%, whereas ischemic wounds did not profit from this therapy. CONCLUSIONS: A positive bacterial wound smear is not inevitably correlated with a protracted leg ulcer healing. Nevertheless a fulminant infection often developed in diabetic ulcers despite the initial inability to demonstrate bacterial growth. In order to start antibiotic treatment as early as possible, a wound smear should be obtained routinely from patients with diabetic ulcers. In chronic venous ulcers, a routine swab does not appear to be indicated as it bears no clinical consequences. The same applies to patients with surgically fully treated peripheral arterial occlusive disease. As ischemia presents the limiting factor, antibiotic therapy in case of infection will not prevent imminent amputation.

Adult↗
PubMed2000

Different kinetics of donor cell populations after isolated liver and combined liver/small bowel transplantation.

Spontaneous tolerance induction after liver transplantation also supports additional transplants, e.g. a small bowel graft, from the same donor (tolerogenic effect). Chimerism serves as a possible explanation of this phenomenon. Isolated liver (LTx) and combined liver/small bowel transplantation (LSBTx) are compared. LSBTx and LTx were performed in the BN --> LEW rat strain combination without immunosuppression. Parenchymal damage during rejection was monitored by sequential standard histology. Donor/recipient populations were identified and further differentiated for immunohistochemical single and double staining. A small number of donor specific leukocytes can be detected on all days in host organs (microchimerism). A significantly larger donor leukocyte population survives long-term in the sinusoids of liver (graft chimerism). Sinusoidal donor leukocytes survive rejection and recover in number after tolerance induction. Rejection of liver allografts and infiltration by host leukocytes are more pronounced after LSBTx than after LTx. Accordingly, during rejection a steeper decline of sinusoidal donor leukocytes is observed after LSBTx and recovery after tolerance induction is not as marked. Microchimerism apparently plays no significant role in either transplantation model. The number of sinusoidal donor leukocytes, however, mirrors closely host immune responses.

Animals↗
PubMed2000

Human antibody response during sepsis against targets expressed by methicillin resistant Staphylococcus aureus.

The identification of target structures is a prerequisite for the development of new treatment options, like antibody based therapy, against methicillin resistant Staphylococcus aureus (MRSA). In this study we identified immunodominant structures which were expressed in vivo during sepsis caused by MRSA. Using human sera we compared the immune response of humans with MRSA sepsis with the immune response of normal individuals and asymptomatically colonized individuals. We identified and characterized four staphylococcal specific antigenic structures. One target is a staphylococcal protein of 29 kDa that exhibited 29% identity to secreted protein SceA precursor of Staphylococcus carnosus. The putative function of this protein, which was designated IsaA (immunodominant staphylococcal antigen), is unknown. The second target is an immunodominant protein of 17 kDa that showed no homology to any currently known protein. This immunodominant protein was designated IsaB. The third and fourth antigens are both immunodominant proteins of 10 kDa. One of these proteins showed 100% identity to major cold shock protein CspA of S. aureus and the other protein was identified as the phosphocarrier protein Hpr of S. aureus. The identified immunodominant proteins may serve as potential targets for the development of antibody based therapy against MRSA.

Amino Acid Sequence↗
PubMed2000

[Measures for allogeneic blood conservation in surgery].

The aim of all efforts to reduce the need of allogeneic blood transfusions is to avoid associated risks. There should particularly be a favourable effect according to the rate of transfusion-transmitted virus infections and immunological side-effects. The acceptance of an individually adjusted lowest haematocrit level and the minimisation of intra-operative blood loss by the application of optimal surgical techniques are among the most essential strategies to reduce or even avoid allogeneic blood transfusions. In addition the following interventions are generally accepted: Preoperative autologous blood donation, where appropriate supported by erythropoietin Preoperative haemodilution, where appropriate supported by erythropoietin Intra- and postoperative blood salvage Topical or systemic pharmacologic interventions to accelerate haemostasis Controlled hypotension Efficacy and indication of the different measures always depend on the individual circumstances of the specific patient. Therefore one should develop an individual approach for every case. In this context the most important subjects are an optimal coordination and if required an appropriate combination of the discussed methods. Algorithms which preoperatively allow approximate calculation of expected transfusion need may be a meaningful tool to facilitate blood conservation planning. However, at the same time one must consider that all strategies to reduce allogeneic transfusion needs are also associated with particular risks. Therefore one has to weigh carefully the pros and cons prior to their application, including the possible alternative of allogeneic transfusion in one's decision making process.

Blood Loss, Surgical↗
PubMed2000

["Reperfusion collapse" phenomenon during post-ischemic reperfusion in experiment].

Postischemic changes of central and regional hemodynamic while various reperfusion regimens have been studied on animal experimental model. We had revealed that despite vasodilatation, peripheral vascular resistance in the postischemic extremity rises, as a result of reperfusion by the lowered perfusion volume. Such phenomenon has been named as "reperfusion-collapse". In spite of the microcirculation disorders progression there have been no significant rising of the peripheral vascular resistance as well as worsening of the regional hemodynamic indexes in the postischemic limb during reperfusion by either normal or increased perfusion volume.

Acute Disease↗
PubMed2000

[Epidemiology and pathophysiology of Barrett esophagus].

The pathophysiology of Barrett's esophagus appears to be a sequential process; the squamous epithelium of the esophagus is replaced by multipotent undifferentiated cells; secondary to cellular damage in the course of gastroesophageal reflux disease these undifferentiated cells further differentiate under the ongoing influence of mucosal damage, thus forming the typical morphology of Barrett mucosa. While the prevalence of gastroesophageal reflux disease amounts to 10% to 30%, the prevalence of Barrett's esophagus is estimated to be 1% in the general population. The epidemiologic data of Barrett's esophagus gain special attention with regard to the fact that the specialized columnar epithelium with intestinal metaplasia represents the only recognized risk factor for the development of adenocarcinoma in the esophagus. Currently it is estimated that the risk of the development of an adenocarcinoma on the basis of Barrett's esophagus is about 30-50 fold higher than that in the general population.

Adenocarcinoma↗
PubMed2000

[Adjuvant immunotherapy of stomach carcinoma with antibody-induced apoptosis].

The human monoclonal antibody SC-1 was isolated from a patient with a diffuse-type adenocarcinoma of the stomach and induces apoptosis of stomach carcinoma cells by binding a stomach-carcinoma-associated isoform of CD55/DAF-B. In a first clinical trial with 20 patients with poorly differentiated stomach adenocarcinoma of diffuse-type received 20 and 30 mg of purified SC-1 antibody intravenously, followed 24 or 48 h later by gastrectomy and lymphadenectomy. In 90% of the cases a significant induction of apoptotic activity was measured in primary tumors as compared with earlier biopsy material and in 50% of the patients a significant regression of tumor mass could even be determined histopathologically. No toxic crossreactivity was observed with normal tissue or organs of patients. These data show, that the human monoclonal antibody SC-1, which induces tumorspecific apoptosis, can be successfully used for adjuvant therapy.

Adenocarcinoma↗