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Biomedical subjects

M Dierich

Publications and source records attributed to M Dierich.

17 recordsLinked to original sources
PubMed1992

Diagnosis of tuberculous meningitis by detection of tuberculostearic acid in cerebrospinal fluid.

Tuberculous meningitis still poses a major diagnostic problem. Recently, several new techniques for rapid diagnosis of tuberculous meningitis have been developed. One of these newer techniques is the detection of mycobacterial fatty acids, using gas chromatography--mass spectroscopy. In this study we evaluated the sensitivity and specificity of this recently reported method in a blind trial. The sensitivity was found to be 100%, specificity only 91%. The number of false positive results limits the value of this test in the primary diagnosis of tuberculous meningitis. Nonetheless, we consider this method to be a valuable tool for establishing the diagnosis in culture-negative patients presenting with signs and symptoms suggestive of tuberculous meningitis.

Diagnosis, Differential↗
PubMed1991

Human complement factor H: two factor H proteins are derived from alternatively spliced transcripts.

The human complement factor H is an important component in the control of the alternative pathway of complement activation. We have previously shown that a least three factor H homologous mRNA species of 4.3 kb, 1.8 kb and 1.4 kb in length are constitutively expressed in human liver. In addition, several factor H-related proteins have been detected in human sera using antibodies directed against the classical human factor H glycoprotein of 150 kDa. The structure of the additional polypeptides has not been shown so far. Circumstantial evidence suggests that the 1.8-kb mRNA might encode the 43-kDa factor H-like polypeptide. Here we report the isolation, characterization and eukaryotic expression of the first full-length cDNA representing the major 4.3-kb mRNA and the 1.8-kb mRNA of human factor H. We show that the 4.3-kb transcript encodes the 150-kDa-factor H glycoprotein and the 1.8-kb mRNA the 43-kDa factor H polypeptide. The identity of the two cDNA in a region of 1400 nucleotides suggests that the two factor H-related transcripts are derived from one gene by a process of alternative splicing.

Amino Acid Sequence↗
PubMed1991

Change in HIV-antibody seroprevalence rates in i.v. drug dependent prisoners.

In 1985 a high HIV-seroprevalence (44.2%) was found in a cohort of parenteral drug addicted prisoners in Innsbruck, Austria. In a longitudinal study from March 1985 to March 1989 we investigated the epidemiology of HIV-infection as well as possible changes in the drug taking behaviour of this defined population at risk. During the study HIV-seroprevalence rates in drug dependent prisoners showed a statistical decrease to 30%. A concomitant increase in admission to any kind of therapy programmes as well as an increasing change from 'heavy use' (mainly taking heroin i.v.) to 'non-heavy use' (mainly taking drugs orally) could be noted. The influence of preventive measures, such as comprehensive AIDS-information, special therapy programmes including the methadone substitution programme, and the unrestricted availability of needles and syringes is discussed.

Adolescent↗
PubMed1988

Cytomegalovirus infection.

Interest has focused on cytomegalovirus (CMV) infections during recent years for two reasons: First, the number of immunocompromised patients with CMV infections has risen continuously and, secondly, recent advances in basic research have clarified some of the mechanisms of persistent and recurrent CMV infection. Three different clinical pictures can arise with CMV infection. In healthy individuals most of the CMV infections are not clinically apparent. In immunocompromised patients CMV causes a wide spectrum of diseases and is one of the predominant causes of death in AIDS patients and bone marrow transplant recipients. The most important problem for public health associated with CMV are connatal and perinatal CMV infections. Progress has been made with treatment of CMV infection in immunocompromised patients with inhibitors of viral replication.

Acquired Immunodeficiency Syndrome↗
PubMed1987

[Effect of long-term preventive use of TMPS on the composition and resistance behavior of aerobic fecal flora].

Trimethoprim Sulfa is a valuable agent in the prophylaxis of Pneumocystis carinii pneumonia in immunocompromised children. Like several other antimicrobial substances also TMPS has an impact on the normal bacterial flora of children. TMPS sensitive enterobacteria are eliminated from the gut flora within 48 hours. The impact on the total number of aerobic organisms and the composition of the fecal flora however is just moderate. Major changes in gut flora result from previous administration of antibiotic and chemotherapeutic agents or from environmental changes (e. g. discharge into ambulatory care). The gut flora of patients under such chemoprophylaxis is a major source of TMPS resistant aerobic bacteria in the hospital and requires careful disposal of these wastes.

Adolescent↗
PubMed1986

Influence of cephalosporines III generation with varying biliary excretion on fecal flora and emergence of resistant bacteria during and after cessation of therapy.

Excretion of an antibiotic bile may result in high intraintestinal concentrations and thus alteration in the fecal flora. We investigated the effect of ceftriaxone (45% biliary excretion) and cefotaxime (less than 5% biliary excretion) on the aerobic fecal flora. Ceftriaxone eradicated susceptible enteric organisms and resulted in overgrowth of Candida spp. and resistant enterococci. In some patients multiresistant gram negative bacteria appeared during of after therapy. Cefotaxime had a moderate effect on fecal microecology and did not promote the emergence of resistant organisms.

Bacteria↗
PubMed1985

The action of human C3 in soluble or cross-linked form with resting and activated murine B lymphocytes.

The third component of complement C3 has been implied in the stimulation of B lymphocytes to proliferation and maturation for Ig secretion. We have reinvestigated the extent of this activation with either activated or resting murine splenic lymphocytes in serum-substituted cultures. Human C3 was used in either soluble or cross-linked form. Soluble as well as Sepharose-bound or glutaraldehyde-cross-linked C3, over a range of concentrations, was inactive with resting splenic lymphocytes of (C57BL/6J X DBA/2)F1, C3H/HeJ and C57BL/6J nu/nu mice. However, lipopolysaccharide-activated spleen cells, enriched for B cell blasts, were stimulated by immobilized and cross-linked C3, while they did not respond to soluble C3. The extent of restimulation was comparable to that induced by lipopolysaccharide and resulted in both increased proliferation and maturation to Ig-secreting cells. The stimulation of the blast cells appears to be C3 specific, since it can be inhibited by free C3.

Animals↗
PubMed1985

Characterisation of cryptic plasmids in clinical isolates of Bacteroides fragilis.

A screening method for plasmids in the fragilis group of Bacteroides spp. was developed, taking account of the lysozyme resistance of these species; 26 strains, 24 of them B. fragilis, were investigated by this method. Eleven strains contained plasmids and up to three different plasmids were found in individual strains. The plasmids belonged to five different size classes of mol. wt (10(6] 2.8, 3.5, 3.6, 4.2 and 19. Plasmids of equal size showed homology; no homology was found between plasmids of different sizes. Plasmids of equal size showed identical restriction patterns with 17 restriction endonucleases. Restriction maps were constructed for the five classes of plasmid.

Anti-Bacterial Agents↗
PubMed1975

Activation by some T-independent antigens and B cell mitogens of the alternative pathway of the complement system.

A number of T-independent antigens and B cell mitogens were examined for their ability to activate C3 via the alternative pathway of the complement system. Loss of hemolytically active C3, generation of anaphylatoxin activity, and immunoelectrophoretic conversion of C3 and factor B, were checked in normal and C4-deficient guinea pig serum, and, in some cases, in normal human serum. As judged by their activity in these assays, 10 lipopolysaccharides of different origin and constitution, pneumococcus type III polysaccharide, levan, dinitrophenylated aminoethyl-dextran, dinitrophenylated (D-glutamic acid, D-lysin) copolymer, polymerized flagellin, and pokeweed mitogen were all capable of initiating the alternative pathway, but differed with respect to their potency, their relative activity in the presence or absence of C4, and their ability to inhibit C3-turnover at high concentrations. Polyvinylpyrrolidone of intermediate molecular weight (4 x 10(4) daltons) was only active if the most sensitive assay was used (anaphylatoxin generation). Other species of polyvinylpyrrolidone, depolymerized pneumococcal polysaccharide, aminoethyl-dextran, [D-glutamic acid, D-lysin] copolymer, phytohemagglutinin and concanavalin A failed to activate C3. C3-consumption by concanavalin A was due to nonspecific binding.

Anaphylaxis↗
PubMed1974

Complement-dependent B-cell activation by cobra venom factor and other mitogens?

It has been proposed that two distinct signals are required for the triggering of the precursors of antibody-forming bone marrow-derived cells (B cells): (a) the binding of antigen or of a mitogen to the corresponding receptor sites on B-cell membranes and (b) the interaction of activated C3 with the C3 receptor of B lymphocytes. There is growing evidence that B-cell mitogens and T (thymus-derived cell)-independent antigens are capable of activating the alternate pathway of the complement system (bypass). Therefore, the effect of another potent bypass inducer was investigated with regard to B-cell activation and the role of C3. Purified, pyrogen-free cobra venom factor was mitogenic for both T and B lymphocytes (cortisone-resistant mouse thymus cells and lymph node lymphocytes from congenitally athymic mice). Venom factor could substitute for T cells by restoring the potential of antibody formation to sheep red blood cells in mouse B-cell cultures supplemented with macrophages or 2-mercaptoethanol. Venom factor may be capable of conferring activated C3 to the C3 receptor of B lymphocytes: preincubation of lymphoid cells with homologous serum or plasma, 10 mM EDTA, and sepharose-coupled venom factor converted with serum to an enzyme active against C3, inhibited their capacity to subsequently form rosettes with sheep erythrocytes sensitized with amboceptor and C5-deficient mouse complement. In the absence of EDTA, preincubation of freshly prepared B-cell suspensions with C3-sufficient homologous serum also blocked their subsequent interaction with complement-sensitized erythrocytes and at the same time rendered them reactive to an otherwise T-cell-specific mitogen. Moreover, mitogen induced B-cell proliferation in lymph node (but not in spleen) cell cultures, appeared to depend on the availability of exogenous C3: zymosan-absorbed fetal bovine serum (only 8.3% site-forming units remaining) supported T-cell activation by phytohemagglutinin, concanavalin A, and venom factor, but failed to sustain B-cell stimulation by pokeweed mitogen, lipopolysaccharide, and venom factor. T-cell-dependent antibody formation in composite cultures containing T cells or T-cell-substituting B-cell mitogens, B cells, and macrophages, always required the presence of C3-sufficient serum.

Animals↗