Search PubMed⌕ Search

Biomedical subjects

R Burger

Publications and source records attributed to R Burger.

At least 163 records · Page 9Linked to original sources
PubMed1982

[Plasma exchange in progressive lupus nephritis].

The clinical course in 8 patients with systemic lupus erythematosus (SLE) complicated by sever lupus nephritis (LN) with progressive renal insufficiency was investigated to evaluate the therapeutic role of plasma exchange in this disease. In 6 patients treated with corticosteroids and immunosuppressive drugs, only a creatinine level exceeding 4.0 mg% resulted in hemodialysis or death. In 2 patients under additional plasma exchange the creatinine value fell below 4.0 mg% and was stabilized at that level over a now lengthy period of time. It cannot yet be concluded that additional plasma exchange definitely prevents hemodialysis. However, stabilization of renal function could optimize conventional therapy, thereby limiting side effects as well as risk of infection.

Adolescent↗
PubMed1982

Conformational changes in C1q after binding to immune complexes: detection of neoantigens with monoclonal antibodies.

The formation of neoantigens within the C1q molecule after the binding of C1r and C1s to C1q and the binding of C1q to immune complexes is described. The neoantigens were detected by different monoclonal anti-C1q antibodies. This immunochemical study supports the hypothesis drawn from functional studies that the activation of the classical C pathway results from conformational changes within the C1q molecule leading to the activation of C1r and subsequently C1s.

Animals↗
PubMed1982

Differentiation of C3b receptors on human lymphocytes, phagocytes, erythrocytes and renal glomerulus cells by monoclonal antibodies.

C3b receptor protein was purified form human erythrocytes by 2 M KBr solubilization and affinity chromatography on C3-coated sepharose. This material served as antigen for raising monoclonal antibodies. To investigate the distribution and antigenetic relationship between the receptors for C3b on human erythrocytes, lymphoid and phagocytic cells, as well as kidney cells three monoclonal antibodies were selected which inhibited the binding of EAC14 degrees 23b to complement receptor-bearing cells. This could be shown for human erythrocytes by inhibiting the immune adherence reaction, for tonsil lymphocytes, Raji cells, and guinea-pig spleen cells by inhibition of rosette formation of these cells with EAC14 degrees 23b, and for human renal glomeruli by blocking of the the adherence of EAC14 degrees 23b to kidney sections. In contrast, these monoclonal antibodies were not capable of inhibiting rosette formation of human granulocytes and monocytes with EAC14 degrees 23b. The antibodies only interfered with the rosette formation, of EAC14 degrees 23bi and EAC14 degrees 23d with Raji cells and tonsil lymphocytes-if at all-at high concentrations, whereas the rosette formation of Raji cells and tonsil lymphocytes with EAC14 degrees 23b was influenced by supernatants of the selected clones up to a dilution of 1:10(3) to 1:10(5).

Animals↗
PubMed1981

Activation of the alternative pathway of complement: efficient fluid-phase amplification by blockade of the regulatory complement protein beta1H through sulfated polyanions.

Current concepts of activation of the alternative pathway of complement (APC) focus on the central role of an amplification mechanism triggered by C3b which is covalently bound to the surfact of activating substances. Using sulfated polyanions as model substances, an efficient fluid-phase activation of complement is demonstrated in contrast to solid-phase activation. It is shown that particulate high-molecular weight sulfated polyanions are capable of reversible binding the guinea pig and human regulatory protein beta1H. This fixation leads to an extensive activation of C3 and factor B because the regulatory function of beta1H is blocked in the fluid-phase C3b-dependent amplification system of the APC. Addition of beta1H-depleted C4-deficient guinea pig serum reconstitutes the physiological control mechanisms of the APC. Guinea pig beta1H, purified to homogeneity, is described as a 160000 dalton protein of a single-chain structure. In addition, highly specific and sensitive test systems for beta1H are described.

Absorption↗
PubMed1981

Monoclonal antibodies to guinea pig Ia antigens. I. Production, serologic, and immunochemical characterization.

Xenogeneic antibodies to guinea pig Ia antigens were produced by application of the hybridoma technique. BALB/c mice were immunized with the Ia-positive B cell leukemia line EN-L2C of strain 2 guinea pigs, and the spleen cells were fused to the mouse myeloma line NS-1. Culture supernatants of hybrids growing in the selective HAT medium were screened in a binding assay, and hybrids selectively reactive with EN-L2C but not with its Ia-negative variant BZ-L2C were cloned. Ascitic fluid was produced and used as a source of antibody. Four independently derived antibodies proved to be specific for Ia antigens. Two of the antibodies (25E3 and 25E11) seemed to recognize alloantigenic determinants on strain 2 Ia antigens in that they bound only to the cells of strain 2 but not to the cells of strain 13 animals. Two other antibodies (22C4 and 27E7) were found to react with both strain 2 and strain 13 cells, and immunoprecipitation experiments revealed that these antibodies were directed to common determinants shared between certain strain 2 and strain 13 Ia antigens. All antibodies were cytotoxic in the presence of complement for EN-L2C (but not for BZ-L2C) leukemia cells and for lymph node, spleen, peritoneal exudate cells, thymocytes, and purified T cells of strain 2 guinea pigs. In addition, 22C4 was cytolytic for cells of both strains. These results indicate that antibodies can be obtained through the hybridoma technique that are able to distinguish different determinants on Ia antigen molecules of te guinea pig. These antibodies should provide a useful tool for further study of the role of Ia antigens in cellular interaction and Ia-Ir gene function.

Animals↗
PubMed1981

Linkage of total deficiency of the second component (C2) of the complement system and of genetic C2-polymorphism to the major histocompatibility complex of the guinea pig.

In the guinea pig six common phenotypes for hemolytically active C2 were detected. They resulted from three allotypic variants: a basic C2B and two more acidic variants C2A and C2A1. (The gene frequency for C2B in the outbred population was 0.36, 0.33 for C2A, and 0.31 for C2A1.) These variants were inherited as autosomal codominant traits. A strong linkage-disequilibrium between C2 and C4 allotypes was observed consisting of the pairs C2A1-C4F. C2A-C4S, whereas C2B was associated with either C4S or C4S1. To investigate the linkage of C2 to the MHC a family of strain 2 X strain OM3 was studied: the C2B allotype segregated with the strain haplotype of OM3 whereas C2A1 does the same with the strain 2 haplotype. During the C2-typing, an animal totally deficient in hemolytic C2 activity was discovered. Its C1, C4, C3, C5, factors B, D, and H were normal. Breeding yielded finally homozygous and heterozygous-deficient individuals. The latter ones exhibited 50 to 60% of the hemolytic activity of normal guinea pigs. Combined typing data of C4, C2 and GPLA showed that the deficient gene behaved like a rare, silent allele of C2, which is GPLA-linked and inherited like the normal C2-variants. An antiserum against C2 was raised in C2-deficient animals, which reacted with normal guinea pig serum but not with serum from C2-deficient animals. No cross-reactivity with human or mouse serum could be detected.

Alleles↗
PubMed1980

Monoclonal antibodies to guinea pig Ia antigens. II. Effect on alloantigen-, antigen-, and mitogen-induced T lymphocyte proliferation in vitro.

Four xenographic monoclonal antibodies to guinea pig Ia antigens were tested for their inhibitory effects on antigen-, alloantigen-, and mitogen-induced T cell proliferation. All four monoclonal antibodies reacted with strain 2 Ia antigens, and all four were capable of inhibiting the strain 13 against strain 2 mixed leukocyte reaction (MLR) by 50-70%; the two monoclonals that reacted with strain 13 Ia antigens were also capable of inhibiting the strain 2 against strain 13 MLR. In contrast, an analysis of the effects of a single monoclonal antibody on the responses to several antigens demonstrated a selective monoclonal pattern of inhibition in that the responses to some, but not all, antigens were inhibited. These results suggest that monoclonal antibodies react with different parts of Ia molecules that may have different functional roles and that certain parts of an Ia molecule participate in the presentation of certain antigens, whereas other regions of the same molecule present different antigens.

Animals↗
PubMed1980

In vivo inactivation of gentamicin by carbenicillin and ticarcillin.

Inactivation of aminoglycosides by carbenicillin and ticarcillin is a well-recognized in vitro phenomenon. Isolated case reports of in vivo inactivation of gentamicin by either carbenicillin or ticarcillin exist. We report a case of nearly complete in vivo inactivation of gentamicin by both ticarcillin and carbenicillin in the same patient. In the absence of either of the penicillin derivatives, the patient demonstrated predictable plasma concentrations and elimination characteristics of both gentamicin and tobramycin. As in previous reports, the interaction was intensified by high-dose carbenicillin-ticarcillin therapy in the face of underlying renal impairment. When using ticarcillin or carbenicillin along with gentamicin in renally impaired patients, special attention must be paid to both the gentamicin and carbenicillin-ticarcillin doses used and the plasma concentrations obtained.

Acute Kidney Injury↗
PubMed1978

[The re-emergence of human rabies in Switzerland. A case history].

The circumstances, clinical symptoms, and outcome of a case of human rabies are reported. The disease was conveyed by a housecat. Since the report gave no cause for concern, antirabies vaccination was not considered to be necessary. After a delay of 157 days prodromi appeared and the patient was finally hospitalized 3 days later displaying signs of the encephalitic stage. After 2 days, the patient went into the paralytic stage; death occurred 3 days later due to refractory circulatory and respiratory failure. In endemic rabies areas such as Switzerland, human rabies may, as demonstrated by our case report, always sporadically occur. Rabies should be considered in cases of encephalitis or encephalitis-like syndromes.

Adult↗
PubMed1977

[Adverse reactions to drugs in hospitalized medical patients (author's transl)].

Prospective research showed that unwanted side-effects resulting from medical therapy were found in 20,6% of all patients hospitalized in our medical clinic during a period of one year. Part of these side-effects was considered a possible reason for admission to the hospital and a cause of complications during the clinical treatment. The side-effects were classified according to their severity, duration, symptomatology and pathogenesis. Furthermore, the frequency of side-effects was studied with regard to age, sex and groups of drugs. It was possible to predict about 80% of the side-effects by considering pharmacological properties and individual risk-factors. The careful integration of these criteria into the treatment plan and the observation of the course of the disease is the basis for calculating the probability of occurrence of side-effects.

Adolescent↗
PubMed1977

Choice of ophthalmic artery branch for Doppler cerebrovascular examination: advantages of the frontal artery.

One hundred normal young adult volunteers were assessed by directional Doppler ultrasound to determine which branch of the ophthalmic artery was most suitable for assessment of the patency of the extracranial internal carotid artery. Each frontal artery of all subjects had normal flow direction and response to compression of the temporal, facial, and common carotid arteries. One supraorbital artery of 2 subjects had reversed flow supplied by the ipsilateral temporal artery and was probably a palpebral artery in each of these individuals. The nasal artery carried reversed flow in 39% of the individuals and was undetectable unilaterally in 2 subjects. From these data we conclude that the frontal artery is the most suitable branch of the ophthalmic artery for Doppler ultrasonic examination. Evaluation of directional flow in the frontal artery and of the influence of compression of all branches of the external carotid artery as well as the common carotid artery is a highly reliable technique to identify significant obstruction of the extracranial internal carotid artery.

Adult↗