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Biomedical subjects

U Nydegger

Publications and source records attributed to U Nydegger.

At least 19 recordsLinked to original sources

Intravenous immunoglobulin in the treatment of spontaneously acquired factor VIII:C inhibitors.

Intravenous immunoglobulin (IV Ig) is useful in most patients with spontaneous factor VIII:C (FVIII:C) inhibitors, but some complete failures also are observed. Among patients responding to this therapy, decreases in FVIII:C autoantibody titer occurs within 24-48 hours and may lead to suppression of inhibitor activity. The prolonged response observed in some cases suggest an effect on autoantibody synthesis. The immediate decrease in FVIII:C inhibitory activity after IV Ig infusion indicates a direct interaction between IV Ig and the autoantibody. This effect is reproducible in vitro by mixing the patient's plasma and Ig at an appropriate molar ratio, which differs in each patient. Similarly, incubation of Ig with F(ab)'2 fragments of a patient's IgG and Ig reproduces inhibition, and this result indicates that the interaction is mediated by antigen binding sites (epitopes) on the immunoglobulins. The suggestion is that an idiotype- anti-idiotype mechanism must be at work. The origin of such anti-idiotypes in Ig prepared from pooled plasma of several thousand blood donors is unclear. The F(ab)'2 fragments were prepared from individual blood donors and tested in similar experiments with F(ab)'2 fragments of three distinct spontaneous FVIII:C inhibitors. The plasma level of anti-idiotypic antibodies reacting with FVIII:C inhibitors varied according to age and gender.

Antibodies, Anti-Idiotypic

[Benefits and side effects of preoperative autologous blood donation in 11 heart surgery patients].

Patients scheduled for cardiac surgery are prone to adverse reactions during blood donation due to hemodynamic instability. 11 selected patients donated three units of red blood cell concentrates and three units of fresh frozen plasma (FFP) preoperatively in 11-day intervals under careful hemodynamic monitoring. 24 hours preoperatively autologous plasmapheresis (500 ml) was carried out in 10 patients at bedside. No complications were seen in any patients. The patients' mean hemoglobin concentrations were 142 +/- 11, 133 +/- 6, 128 +/- 7 and 126 +/- 7 g/l (mean +/- 1 SD) before each autologous blood donation and before the plasmapheresis respectively. No significant changes were noted in major hematological and chemical screening tests. Serum iron, iron-binding capacity and ferritin levels remained within the normal range. Due to additional perioperative blood saving methods, such as reinfusion of centrifuged oxygenator-blood (559 +/- 119 ml) and shed mediastinal blood (518 +/- 353 ml), only two patients needed additional transfusion of 1 homologous red cell unit each. On average 2.18 autologous red cell concentrates were retransfused per patient.

Blood Chemical Analysis

[Anti-A/B-IgM/G immune response to accidental A-O transfusion and to Toxocara canis infestation].

We have applied a sensitive and reproducible AB0-ELISA, in combination with a hemagglutination test, for the study of class- and subclass specific humoral immune response in the AB0 system upon challenge by the intravenous route (A-type blood in a 0-recipient) and by helminthic A and B blood group antigen (Toxocara canis). After accidental transfusion, peak booster concentrations of anti-A-IgG reached 411 micrograms per g total IgG, with IgG1 and IgG2 subclasses evenly distributed. With Toxocara canis immunity, anti-A/B-IgG rose to 244 and 382 micrograms/g IgG, nearly 100% over the mean value of 15 healthy blood donors; it is noteworthy that these IgG levels almost exclusively consisted of IgG1. Both observations suggest that unusual presentation of A antigen to host leads to a predominant if not exclusive IgG booster reaction.

ABO Blood-Group System

High-dose intravenous IgG treatment and renal function.

In an open trial of high dose intravenous IgG (IVIG) treatment in nephrotic patients with glomerulonephritis, the first six patients so far studied showed a transient rise in plasma creatinine. This increase was not associated with any symptoms and the urinary deposit remained unchanged. Two other patients with pre-existing renal impairment but without nephrotic syndrome had a transient and reversible rise in plasma creatinine immediately after IVIG. These observations suggest that high-dose IVIG infusion can produce short-lived disturbances in renal function in patients with kidney diseases.

Adult

Fluctuation of anti-A and anti-B histo-blood-group antibodies in a patient after liver transplantation.

The concentrations of anti-A and anti-B IgM and IgG antibodies have been studied in the serum of a patient with blood group AB who received a type A donor liver. A newly developed ABO-ELISA was used for this purpose and the values were compared to hemagglutination titers. During the postoperative study period over 8 weeks, the anti-A and anti-B levels showed a higher fluctuation than was measured in preoperative samples. Thus, in this AB-type patient, anti-A IgM varied 10-fold, anti-A IgG 20-fold and anti-B IgG 16-fold. Peak values corresponded to rejection episodes. Immunoactivation in the patient was further documented by the presence of abnormally high levels of soluble interleukin-2 receptors (sIL-2R) in serum samples. The study shows that monitoring of anti-A/B antibodies may represent a further criterion to follow-up transplanted patients during the critical postoperative graft acceptance period.

ABO Blood-Group System

[Orthotopic liver transplantation at the Island Hospital. Initial experiences 1985-1990].

Between 1985 and 1990 22 orthotopic liver transplantations (OLT) were realized in 19 patients. Active infection and diffuse splanchnic venous thrombosis were the only contra-indications to the intervention. Sixteen patients were transplanted electively; three had to be retransplanted urgently. Three patients had an urgent primary transplant. The incidence of surgical complications related to liver implantation was fair. One patient (5%) developed a late portal vein thrombosis; another patient (5%) had to be retransplanted because of hepatic artery thrombosis. All patients presented one or more major postoperative complications. All, but one, patients had a rejection of the allograft; five of them needed treatment with mono- or polyclonal antilymphocytic sera to reverse the rejection. One patient was retransplanted because of a hyperacute rejection. The six-month survival in this series is 68.5% (13 of 18 patients); one patient died 7 months post-OLT due to a neurological complication of her Wilson disease. Quality of life (from 6 to 64 months post-OLT) is excellent in the 12 long-term survivors. This small experience of the Bernese transplantation program shows that liver transplantation is a safe surgical procedure allowing excellent quality of life in a majority of patients.

Adult

[Effects and side effects of intravenous gamma globulin I: the problem of immune complex formation].

This is an original contribution to the side effects of i.v. gamma globulin in patients with immunodeficiency. 73 therapies were carried out, 9 patients suffered from partially life-threatening complications. All side effects were fully reversible and occurred during the transition from antigenaemia to antibody-excess. Immunecomplexes could be quantified and C4 decreased. In view of these results we have modified our protocol giving 5 S prior to 7 S. No further complication was seen in the following 148 therapies. Hence we can conclude, that at least some complications of the i.v. gamma globulin-therapy is due to the formation of immunecomplexes and can be prevented by the application of 5 S prior to 7 S.

Adolescent

[Quantitative and qualitative analysis of various blood-preserving measures in heart surgery].

We assessed quantitative aspects of blood salvage retrospectively in 270 consecutive coronary bypass patients over one year. They were assigned either to group A (n = 10, Cellsaver [Haemonetics]), B (n = 189, centrifugated oxygenator blood), C (n = 107, retransfusion of shed mediastinal blood) or D (n = 74, combination of method B and C). In addition, blood quality was studied prospectively in group A (n = 5), B (n = 10) and C (n = 10) and each group compared to a control group. Results (mean values/patient) were: Blood salvage with A yielded 570 +/- 230 ml (hematocrit = 50%), B 509 +/- 156 ml (69%) and C 593 +/- 430 ml (26%). The required homologous blood products, i.e. packed cells (PC) and fresh frozen plasma (FFP) diminished significantly when combined autologous blood salvage was used (PC 6.0 +/- 3.4 vs 3.4 +/- 1.9, p less than 0.05; FFP 3.4 +/- 3.8 vs 2.6 +/- 3.0). Autologous erythrocyte function assessed by 2,3DPG was normal in all three methods (range 14.77-16.03 mumol/gHb). ATP was nearly normal in A (3.34 +/- 0.45 mumol/gHb), reduced by 20% in B (3.21 +/- 1.14 mumol/gHb) and by 30% in C (2.56 +/- 0.78 mumol/gHb) compared to the corresponding preoperative patient value. Hemolysis (free plasma hemoglobin) (was elevated in A (63 +/- 7 mg/dl), B (202 +/- 57 mg/dl) and C (211 +/- 44 mg/dl). However, no increase of free plasma hemoglobin was encountered in our patients after retransfusion of either A, B or C. No side effects were detected and bacteriology remained negative in all examined blood samples in C.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate

[Retransfusion of thoracic drainage blood: qualitative analysis].

In a prospective randomized study 10 patients received their shed mediastinal blood after elective coronary artery bypass surgery and were compared to 10 control patients without retransfusion. The quality assessment can be summarized as follows (mean +/- 1 SD): 1. Hemoglobin concentration of the shed blood was 9.6 +/- 1.45 g/dl. 2. The energy rich phosphate compounds of the shed blood erythrocytes were 2.6 +/- 0.8 mumol/gHb ATP (70% of the patients preoperative value) and 14.8 +/- 4.2 mumol/gHb 2.3-DPG (normal). 3. Proteins, immunoglobulins and especially albumin in the shed blood were not significantly different from the patients own values. 4. No electrolyte changes, safe for a slight increase in potassium (5.7 +/- 0.7 mmol/l). 5. The activated clotting time of the patient did not change during retransfusion. 7. Plasma free hemoglobin was elevated to 211.1 +/- 44.3 mg/dl in the shed blood; however, no significant increase could be noted in the retransfused patients and no hemoglobinuria occurred. Postoperative retransfusion of shed mediastinal blood is a simple and safe method of autologous transfusion early after cardiac surgery and should be combined with other methods of blood salvage. The qualitative advantages of blood retransfusion consist in the absence of storage damage and in the preservation of autologous proteins and immunoglobulins.

Blood Chemical Analysis

[Current overview of diagnostic possibilities of complement analysis].

The complement system is composed of at least 21 serum proteins and 8 cell surface receptors sensitive to complement components or their fragments. Qualitative and quantitative analysis of complement components in clinical samples has become standard procedure in many laboratories thanks to the availability of easy-to-perform test kits. However, interpretation of results is still a task that requires great skill and the situation are rare, in which analysis of the complement system goes beyond diagnosis into therapeutic consequences. The present paper is an update of previous similar reviews now available in the international literature; in addition, the author attempts at bringing the often complicated world of complement and clinical practice together and thus contributes to answering the question: what should the clinician know about complement?

Antigen-Antibody Complex

[Alternative complement pathway (author's transl)].

The dual role of the alternative complement pathway in recognition of foreign substances by a non-immune host and in the intrinsic regulation of the complement sequence is now well recognized. Activation of this pathway occurs through escape from its regulatory mechanisms induced by the activating principle; its functional expression depends on the respective levels of the component proteins C3, factor B, factor D and properdin, and on the control proteins beta 1H and C3bINA. This article presents recently acquired knowlege on the molecular mechanisms of activation, regulation and behaviour under pathological conditions of the alternative complement pathway.

Complement Activation

[The detection of soluble immune complexes (author's transl)].

The detection and characterization of soluble immune complexes is complicated by the broad spectrum of complexes occurring in human pathology. Thus, differences in immune complex size, specificity and ability to interact with immunologic effector systems such as complement or cells, suggest variable pathogenic potential. Therefore, a variety of techniques for detection should be available. The introduction of radioimmunoassays and the recently improved knowledge of immune complex biochemistry have lead to the description of a large number of detection procedures, which in turn has widened the catalogue of diseases associated with immune complexes. Among 50 procedures known today, this article selects some pertinent tests which are critically discussed with respect to their specificity, sensitivity and possible interest in clinical medicine.

Antigen-Antibody Complex

Complement activation in pneumonia.

Complement analyses performed on serially collected plasma samples from 10 patients during acute infectious pneumonia or bronchopneumonia showed normal or increased values for hemolytic activity and Clq, C4, C3, and factor B levels. However, the levels of C3 breakdown products (C3d) were significantly (greater than 2 SD) increased in six patients during the first three days of observation, suggesting that hypercatabolism of complement components may occur during the acute phase of infectious pneumonia concomitant with a hypersynthesis of some complement components. Evidence of circulating immune complexes was obtained only in two patients with the 125I-Clq Binding Test.

Acute Disease

Immune complexes and complement in rheumatoid arthritis.

Immune complexes have been shown to occur frequently during rheumatoid arthritis. They have been found in blood, in the synovium and in other extravascular lesions. The recent development of methods for the quantitation of immune complexes provided new tools to evaluate the possible role of immune complexes in rheumatoid arthritis. Immune complexes which appear in synovial fluid are in higher concentration than in serum and have particular physicochemical properties. They likely result from a local formation in the synovium and seem to be directly involved in the generation of the local inflammation. High levels of circulating immune complexes are usually associated with the development of extra-articular vascular lesions. One of the major biological activity of immune complexes is to activate the complement system. There is indeed evidence of complement activation in circulating blood as well as in synovial fluid in patients with rheumatoid arthritis. The presence and the concentration of complement breakdown products in these fluids correlates with the clinical activity. Therefore, the analysis of immune complexes and of complement components appears useful for diagnosis and follow-up, and for the understanding of the pathogenesis of the disease.

Antigen-Antibody Complex

[Cutaneous plasmacytosis and polyclonal cryo-immunoglobulinemia].

A 65-year-old male patient is described who presented with (1) large violet cutaneous plaques on the left side of the body, characterized by dense plasmocyte infiltration of the dermis which appeared benign and largely negative to immunofluorescence, (2) massive polyclonal cryoglobulinemia (type III) without paraproteins, and (3) intermittently marked peripheral monocytosis and thrombopenia without significant medullary changes. Compared with the cases reported in the literature, and after a thorough immunological investigation, this syndrome cannot be entirely assimilated to any entity described up to the present time. Hypothetically, a reactional disorder is the most likely.

Aged

[Evaluation of the role of circulating antigen-antibody complexes in the pathogenesis of glomerular nephropathies].

Immunofluorescence studies of the glomeruli in patients suffering from glomerulonephritis (GN) suggest the deposit of immune complexes from the circulating blood. Immune complexes were quantitated using a sensitive radioimmunoassay from sera of 41 patients with GN drawn at the time when renal biopsy was performed. Simultaneously, degradation products of C3 (C3d) were measured. Eleven of 12 patients with GN secondary to a systemic disease (usually LED) presented increased C1q-binding activity of their sera (C1q-BA). C3 was further demonstrated in 9 of these patients, suggesting the presence of circulating immune complexes. By contrast only 2 of 12 patients with idiopathic GN characterized by deposits of complement and IgG in the glomeruli exhibited increased C1q-BA. One of 17 patients with idiopathic GN without deposit of immunoglobulins and C3 in the glomeruli also had increased C1q-BA. The results observed in the group of patients with idiopathic GN with glomerular deposits could be accounted for either by a transitory or minimal presence of immune complexes or by local formation of complexes in the glomerular structures.

Antigen-Antibody Complex