Biomedical subjects

M Mäder

Publications and source records attributed to M Mäder.

At least 37 records · Page 2Linked to original sources

PubMed1998

Beta-trace protein concentration in cerebrospinal fluid is decreased in patients with bacterial meningitis.

Although meninges represent a major site of biosynthesis, beta-trace protein (beta-trace) has not been studied in the cerebrospinal fluid (CSF) of meningitis patients. We measured beta-trace in lumbar CSF of normal controls (n = 27) and in patients with various neurological diseases (n = 92) by an immunonephelometric assay. The mean concentration of beta-trace in CSF of control patients was 16.6+/-3.6 mg/l. In bacterial meningitis (n = 41), CSF beta-trace was significantly decreased (8.7+/-3.9 mg/l; P< 0.001), whereas in spinal canal stenosis it was elevated (29.2+/-10.3 mg/l; P= 0.002). In viral meningoencephalitis (n = 12), beta-trace CSF concentrations were normal. Beta-trace concentrations remained below the normal range even after curing of bacterial meningitis, and normalisation of CSF leucocytes and blood-CSF barrier function. Beta-trace may be a useful tool for studying the pathophysiology of bacterial meningitis.

Adult↗

PubMed1998

A method for preventing artifactual binding of cRNA probes to neurons caused by in situ hybridization.

When in situ hybridization was used for the detection of mRNA for the beta-trace protein (beta-trace; prostaglandin-D-synthase) in sections of rat and porcine brains, unspecific binding reactions of sense and antisense probes to neurons were observed. The beta-trace fragment which served as a template for the synthesis of cRNA probes was blunt end-cloned in the vector pCR-Script SK (+). It was demonstrated that the unspecific signals were caused by artifactual binding of two portions of the cRNA which correspond to sequences of the multicloning site of this vector. These sequences are localized between the SrfI restriction site (or the insert) and the promoter for the T7 RNA polymerase. Thus, artifactual binding could be prevented using riboprobes synthesized by T3 RNA polymerase instead of T7 RNA polymerase. Because of the relatively weak transcription efficiency of T3 RNA polymerase, as compared with T7 RNA polymerase, a blocking procedure was established which allowed successful in situ hybridization with T7 RNA polymerase-synthesized probes. Blocking was performed using synthetic oligonucleotides deduced from the two sequences of the multicloning site which were found to be responsible for artifactual binding.

Animals↗

PubMed1998

Differential release of lipoteichoic and teichoic acids from Streptococcus pneumoniae as a result of exposure to beta-lactam antibiotics, rifamycins, trovafloxacin, and quinupristin-dalfopristin.

The release of lipoteichoic acid (LTA) and teichoic acid (TA) from a Streptococcus pneumoniae type 3 strain during exposure to ceftriaxone, meropenem, rifampin, rifabutin, quinupristin-dalfopristin, and trovafloxacin in tryptic soy broth was monitored by a newly developed enzyme-linked immunosorbent assay. At a concentration of 10 microg/ml, a rapid and intense release of LTA and TA occurred during exposure to ceftriaxone (3,248+/-1,688 ng/ml at 3 h and 3,827+/-2,133 ng/ml at 12 h) and meropenem (2,464+/-1,081 ng/ml at 3 h and 2,900+/-1,364 ng/ml at 12 h). Three hours after exposure to rifampin, rifabutin, quinupristin-dalfopristin, and trovafloxacin, mean LTA and TA concentrations of less than 460 ng/ml were observed (for each group, P < 0.01 versus the concentrations after exposure to ceftriaxone). After 12 h of treatment, the LTA and TA concentrations were 463+/-126 ng/ml after exposure to rifampin, 669+/-303 ng/ml after exposure to rifabutin, and 1,236+/-772 ng/ml after exposure to quinupristin-dalfopristin (for each group, P < 0.05 versus the concentrations after exposure to ceftriaxone) and 1,745+/-1,185 ng/ml after exposure to trovafloxacin (P = 0.12 versus the concentration after exposure to ceftriaxone). At 10 microg/ml, bactericidal antibacterial agents that do not primarily affect cell wall synthesis reduced the amount of LTA and TA released during their cidal action against S. pneumoniae in comparison with the amount released after exposure to beta-lactams. Larger quantities of LTA and TA were released after treatment with low concentrations (1x the MIC and 1x the minimum bactericidal concentration) than after no treatment for all antibacterial agents except the rifamycins. This does not support the concept of using a low first antibiotic dose to prevent the release of proinflammatory cell wall components.

Anti-Bacterial Agents↗

PubMed1998

Enzyme immunoassay detecting teichoic and lipoteichoic acids versus cerebrospinal fluid culture and latex agglutination for diagnosis of Streptococcus pneumoniae meningitis.

A newly developed enzyme immunoassay (EIA) was used to detect the presence of pneumococcal teichoic and lipoteichoic acids in cerebrospinal fluid (CSF) from patients with Streptococcus pneumoniae meningitis who were being treated with antibiotics. All initial CSF samples, which on culture grew S. pneumoniae, were positive in the EIA. A total of 14 subsequent culture-negative samples gave clear signals in the EIA up to day 15 after the onset of antibiotic treatment. For 11 CSF specimens, culture, microscopy, and latex agglutination were negative while the EIA detected pneumococcal antigens. The EIA did not react either with CSF of patients with meningitis caused by bacteria other than S. pneumoniae or by viral pathogens. In conclusion, this EIA can be a valuable tool for the diagnosis of S. pneumoniae meningitis from CSF samples in cases in which prior antimicrobial therapy minimizes the usefulness of culture or other antigen detection tests.

Animals↗

PubMed1997

S-100 protein concentration in the cerebrospinal fluid of patients with Creutzfeldt-Jakob disease.

We evaluated S-100 levels in paired cerebrospinal fluid (CSF) and serum samples in a group of 135 patients referred to the German Creutzfeldt-Jakob disease (CJD) surveillance unit from June 1993 to May 1995. The patients were seen in a prospective case control study. The diagnosis of probable CJD during life was made in any patient presenting with rapidly progressive dementia of less than 2 years' duration, typical periodic sharp wave complexes (PSWCs) in the EEG and at least two of the following findings: myoclonus, visual/or cerebellar symptoms, pyramidal and/or extrapyramidal signs and/or akinetic mutism. Patients presenting with the above clinical signs and symptoms but without PSWCs were classified as possible, while those with a dementia of a duration exceeding 2 years and without PSWCs were classified as other. S-100 was determined in paired CSF and serum samples by a commercially available enzyme-linked immunosorbent assay. In a group of 76 patients with definite and probable CJD, S-100 concentration (median 25 ng/ml, range 2-117) in CSF was significantly higher (P < 0.0001) than in 32 patients diagnosed as other (median 4 ng/ml, range 1-19). Serum levels of S-100 were below 0.5 ng/ml in all groups. At a cut-off of 8 ng/ml an optimum sensitivity of 84.2% with a specificity of 90.6% for the diagnosis of CJD by the determination of S-100 in CSF is obtained. S-100 levels exceeding 8 ng/ml in CSF support the diagnosis of CJD in any patient presenting with rapidly progressive dementia.

Adult↗

PubMed1997

Establishment of an efficient enzyme-linked immunosorbent assay for the determination of human choline acetyltransferase.

A specific and sensitive two-side enzyme-linked immunosorbent assay (sandwich-ELISA) was established for the reliable quantification of human brain and placental choline acetyltransferase (ChAT). In contrast to the radiometric assay developed by Fonnum, which is widely used for the measurement of enzyme activity, the sandwich-ELISA particularly recognized inactivated forms of the antigen. In the assay, affinity-purified polyclonal synthetic peptide antibodies adsorbed to the polystyrene surface of the microtiter plate were employed as capture reagent. Based on standard peroxidase protocols, immobilized ChAT was detected using monoclonal antibodies raised against human placental ChAT. By use of this ELISA, ChAT was determined at various purification stages of the enzyme, in body fluids, during recovery experiments and in sera of patients with severe brain damage.

Adolescent↗

PubMed1997

Limited efficacy of pentoxifylline as anti-inflammatory agent in experimental pneumococcal meningitis.

Dexamethasone appears to show some adverse side-effects as adjunctive anti-inflammatory agent in bacterial meningitis. For this reason, we tested the anti-inflammatory and neuroprotective effect of pentoxifylline administered 15 min before starting antibiotic treatment with ceftriaxone (n = 10) versus antibiotic therapy alone (n = 9) in the rabbit model of pneumococcal meningitis. Pentoxifylline lowered the medians of leucocyte density, tumour necrosis factor-alpha (TNF-alpha) and lactate in the cerebrospinal fluid (CSF), but only leucocyte migration into the subarachnoid space was significantly inhibited 8 h after initiation of therapy (P = 0.01). CSF protein, brain water content, and the entry of ceftriaxone into CSF were not influenced by pentoxifylline. The density of neuronal apoptoses in the dentate gyrus was slightly lower in animals receiving pentoxifylline than in those treated with ceftriaxone only. The median concentration of neuron-specific enolase in CSF was lower in the pentoxifylline-treated group, but the difference was not significant. In conclusion, pentoxifylline showed some anti-inflammatory activity in pneumococcal meningitis, but the substance failed significantly to reduce neuronal damage.

Animals↗

PubMed1997

Detection of T cells reactive to intestinal alkaline phosphatase, an autoantigen in acute bacterial infections, and discrimination between autoantigen-specific CD5+ and CD5- B cells.

Autoantibodies of the IgG isotype, specifically directed against intestinal alkaline phosphatase (IAP), occur transiently in the majority of sera from patients with acute bacterial infections. Sometimes they are observed in autoimmune diseases. Using a T cell proliferation assay, it was found that isolated peripheral blood mononuclear cells (PBMC) from IAP autoantibody (IAPA)-positive patients (n = 18) responded significantly to IAP, whereas proliferation could not be induced in PBMC from healthy donors (n = 11). Significant stimulation of PBMC from patients (n = 11) was not obtained by use of transferrin, a common autoantigen in humans, indicating the specificity of stimulation of IAP-reactive T cells. Furthermore, T cell proliferation was observed when a highly purified IAP fragment (CNBr 21) spanning amino acids 334-462 of the primary structure of IAP was used as antigen. Thus, it was shown that an immunodominant T cell epitope resides within the CNBr 21 fragment which also contains a discontinuous B cell epitope as evaluated previously. Double immunocytochemical staining of T cell-depleted PBMC with IAP and an anti-human CD5 antibody allowed the detection of CD5+ B lymphocytes, which probably produce natural IAPA (nIAPA). These nIAPA-specific CD5+ B cells occurred with approximately the same frequency among T cell-depleted PBMC from healthy donors and those from patients. In contrast, IAPA-producing CD5- B cells were found in B cell-enriched preparations from patients, but not in those from healthy individuals.

Acute Disease↗

PubMed1997

Characterization of monoclonal and polyclonal antibodies to human choline acetyltransferase and epitope analysis.

Choline acetyltransferase (ChAT) was partially purified from human placenta and brain. In order to raise monoclonal antibodies, Balb/c mice were immunized with a preparation from placenta or with a mixture of eight synthetic peptides that were deduced from the primary structures of porcine and human ChAT. Polyclonal antibodies were raised in rabbits against five synthetic peptides deduced from the amino acid sequence of human ChAT. The monoclonal and polyclonal antibodies were characterized by their ability to recognize ChAT in various immunoassays: immunoblot, enzyme-linked immunosorbent assay (ELISA), two-side ELISA and immunohistochemistry. With one exception all monoclonal antibodies recognized ChAT on immunoblots, some were particularly sensitive; one bound active ChAT in ELISA when used as capture reagent; most antibodies recognized immobilized ChAT in ELISA. Two monoclonal antibodies out of nine gave particularly excellent results in staining cholinergic neurons and fibers on sections from rat and primate brain. With the help of nine synthetic peptides it was possible to evaluate two major binding sites for the monoclonal antibodies on the ChAT molecule, comprising amino acids 167-189 and 57-76, respectively.

Amino Acid Sequence↗

PubMed1996

A putative enzyme from various secretions specifically inhibits antibody-antigen interactions.

Various human secretions (intestinal secretion, saliva, nasal mucus, lacrimal fluid) have been found to inhibit the binding of antibodies to their antigens. Various characteristics (e.g. time, pH, temperature dependence, affinity and size exclusion chromatography) suggested that the inhibitory activity was attributable to an enzyme. Further investigations revealed that this enzyme reacted with the Fab portion of immunoglobulin G, specifically with the heavy chain. It is assumed that it represents a novel immunoglobulin-specific protease since similar results were not obtained with proteolytic enzymes from human digestive organs e.g. pepsin, trypsin and chymotrypsin. Finally, investigating saliva it was demonstrated that the putative protease was not identical to enzymes from periodontal bacteria which are proteolytic for the Fc portion of immunoglobulins. The findings could be of general importance in the design of immunoassays which are to be applied to human (and possibly animal) secretions.

Alkaline Phosphatase↗

PubMed1996

Choroid plexus: the major site of mRNA expression for the beta-trace protein (prostaglandin D synthase) in human brain.

Expression of beta-trace protein (beta-trace), recently identified as glutathion-independent prostaglandin D synthase (prostaglandin-H2 D-isomerase; EC 5.3.99.2), was localized in paraffin sections of the human brain by in situ hybridization using digoxigenin-labeled antisense cRNA probes. The mRNA for beta-trace was predominantly found in the epithelial cells of the choroid plexus. Hybridization signals were also obtained in some oligodendrocytes, particularly in the white matter. In the leptomeninges, specific signals were found in meningeal macrophages and in single cells of the arachnoid barrier layer. The cells exhibiting hybridization signals with the antisense cRNA probes for beta-trace were identified by counterstaining with antibodies directed against specific cell markers. Additionally, beta-trace mRNA was localized in tubular epithelial and basal cells of the human epididymis and in different cell types within the seminiferous epithelium of the testis.

Brain↗

PubMed1996

Definition of a discontinuous immunodominant epitope of intestinal alkaline phosphatase, an autoantigen in acute bacterial infections.

In patients suffering from acute bacterial infections specific autoantibodies of the immunoglobulin class G (IgG), directed against intestinal alkaline phosphatase (IAP), are transiently expressed in high titer. The epitopes on IAP which are recognized by these IAP auto-antibodies were investigated using chemical and enzymatic cleavage, followed by two-dimensional electrophoresis and immunoblotting of the fragments. Immunoreactive and nonreactive cleavage fragments were isolated and N-terminally sequenced. An epitope map was constructed by means of sequencing data, relative molecular mass of the fragments, and specific cleavage sites. To evaluate linear epitopes, the overlapping region of the immunoreactive fragments (amino acids 204-484 of the primary structure of IAP) was further analyzed by simultaneous synthesis of 95 peptides on an activated membrane. Four immunoreactive regions were revealed by immunodetection with IAP autoantibody-positive sera. Nine peptides comprising these regions were synthesized quantitatively and coupled to CH-Sepharose. However, specific IAP autoantibodies could not be isolated. This result indicated the absence of continuous epitopes at least in the analyzed region of the molecule. Binding studies with an IAP cleavage fragment suggested a discontinuous epitope involving amino acids 334-371. The results are indicative of an antigen-driven mechanism for the production of IAP autoantibodies initiated and maintained by self.

Acute Disease↗

PubMed1996

A novel enzyme-linked immunosorbent assay for determination of synaptophysin as compared with other quantification procedures.

A two-sided enzyme-linked immunosorbent assay (ELISA) has been established for reliable, specific and sensitive determination of synaptophysin (SYN), an intrinsic membrane protein of the small synaptic vesicles. This ELISA used a highly specific monoclonal antibody (SY 38) as capture reagent and a specific SYN antiserum in combination with a secondary peroxidase-conjugated antibody for detection. Calibration was carried out with immunoaffinity-purified SYN from porcine cortex. The sensitivity was found to be improved substantially when the ELISA was compared with previously used dot-immunobinding assays. This ELISA allowed rapid and reliable determination of SYN from detergent lysed homogenates, partially and highly purified preparations of rat, porcine and human brain. SYN was determined in highly purified small synaptic vesicles, and it was calculated to be 5.8% of total detergent solubilized protein.

Animals↗

PubMed1996

Large-scale purification of synaptophysin and quantification with a newly established enzyme-linked immunosorbent assay.

Synaptophysin (SYP I), an integral membrane protein, was purified on a large scale (0.55 - 2.7 mg) from isolated small synaptic vesicles (SSV) of porcine cortex. In order to achieve this, a conventional purification procedure which consists of size exlusion chromatography, hydrophobic interaction chromatography and chromatofocusing has been developed. This procedure was compared with purification of SYP I by immunoaffinity chromatography. The elution patterns of both procedures were monitored using sodium dodecylsulfate gel electrophoresis (SDS-PAGE) with subsequent Coomassie blue staining of proteins and simultaneous immunoblotting with SYP I-specific antibody. Contaminating proteins with relative molecular masses (M(r)) very similar to SYP I could be removed during the process of purification, demonstrating that the 38 kDa protein found after Triton X-100 lysis of enriched SSV does not exclusively represent SYP I. A specific antiserum was raised in rabbits using a highly purified preparation of SYP I. This antiserum was used in combination with a monoclonal antibody to establish a specific and sensitive enzyme-linked immunosorbent assay (ELISA) which allowed rapid and reliable quantification of this hydrophobic membrane protein in all purification steps, starting with Triton X-100-lysed brain homogenates. Using this ELISA, the concentration of SYP I in highly purified SSV was determined to be 5.8% of solubilized protein.

Animals↗

PubMed1995

Chemical coding of neurons that project from different regions of intestine to the coeliac ganglion of the guinea pig.

The chemical codings of neurons that project from the small intestine, caecum, proximal colon, distal colon and rectum to the coeliac ganglion of the guinea pig were investigated. The coeliac ganglion was injected with the retrogradely transported dye Fast Blue, and each of the regions was examined 6 days later in wholemounts that had been prepared for immunohistochemical localisation of pairs of antigens. In both the small and large intestines, all intestinofugal neurons were immunoreactive (IR) for choline acetyltransferase (ChAT). In each region of the large intestine, the largest population, representing 50-60% of retrogradely labelled neurons in each region, was immunoreactive for ChAT, bombesin (BN), calbindin (Calb) and nitric oxide synthase (NOS). Most intestinofugal neurons in the small intestine contain bombesin and VIP-IR along with ChAT-IR but none contain either Calb or NOS. Thus, nerve endings of enteric origin in the coeliac ganglion that contain NOS-IR or Calb-IR come from the large intestine and those with bombesin-IR but not NOS-IR are from the small intestine. The gastric wall was injected with Fast Blue in order to label noradrenergic (NA) neurons in the coeliac ganglion and to determine, by localisation of NOS and bombesin-IR, whether they receive inputs from the small and large intestine. Some NA neurons received inputs from the large intestine (and perhaps also from the small intestine) and some received inputs exclusively from the small intestine. Most NA neurons that received intestinofugal inputs had the chemical code NA/-; some were immunoreactive for somatostatin (NA/SOM neurons), but those with IR for neuropeptide Y (NA/NPY) rarely received intestinofugal inputs.

Animals↗

PubMed1995

Choline acetyltransferase-like immunoreactivity in small diameter neurones of the rat dorsal root ganglion.

In the rat choline acetyltransferase (ChAT)-like immunoreactivity (ChAT-LI) was demonstrated in the dorsal root ganglion (DRG), in the superficial spinal cord and in the subepithelial layer of the ureter using immunohistochemical techniques. In the L1 DRG, 66% of the neurones were ChAT-LI. They did not express neurofilament immunoreactivity (RT97 negative) but could also contain calcitonin gene-related peptide-like immunoreactivity (CGRP-LI). In the superficial spinal cord and in the subepithelial plexus of the ureter--both areas where high numbers of fine afferent fibres have been demonstrated--CGRP-LI and ChAT-LI were co-distributed, indicating that ChAT can be found in the peripheral and central endings of small afferents. The data provide morphological evidence that a substantial proportion of afferent fibres are cholinergic.

Animals↗

PubMed1995

Neurochemical coding of enteric neurons in the guinea pig stomach.

The aim of this study was to investigate the neurochemical coding of myenteric neurons in the guinea pig gastric corpus by using immunohistochemical methods. Antibodies and antisera against calbindin (CALB), calretinin (CALRET), choline acetyltransferase (ChAT), calcitonin gene-related peptide (CGRP), dopamine beta-hydroxylase (DBH), beta-endorphin (ENK), neuropeptide Y (NPY), neuron-specific enolase (NSE), nitric oxide synthase (NOS), protein gene product 9.5 (PGP), parvalbumin (PARV), serotonin (5-HT), somatostatin (SOM), substance P (SP), tyrosine hydroxylase (TH), and vasoactive intestinal peptide (VIP) were used. Double- and triple-labeling studies revealed colocalization of certain transmitters and enabled the identification of distinct subpopulations of gastric enteric neurons. NPY/VIP/NOS/ENK were present in 28% of all neurons, whereas 11% had NPY/VIP/DBH/ChAT; NOS-only neurons made up 2% of the population. The combination SP/ChAT/ENK occurred in 21% of the population, whereas SP/ChAT/ENK/CALRET and SP/CHAT/SOM/ +/- CALRET was identified in 5% and 6% of all cells, respectively. 5-HT-containing neurons comprised 2% of all cells and could be further classified by the presence of additional antigens as 5-HT/SP/(ChAT) or 5-HT/VIP/(ChAT). Approximately 21% of all neurons contained only ChAT with no additional antigen present and are referred to as ChAT/-. Gastric myenteric ganglion cells were not immunoreactive for CALB, PARV, CGRP, or TH. The results of this study indicate that gastric myenteric neurons can be characterized on the basis of different chemical coding. Neurochemical coding of corpus myenteric neurons revealed some similarities and significant differences in comparison with other regions of the gut. These differences might reflect adaptation of enteric nerves according to regional specialization and the distinct functions of the proximal stomach as a gastric reservoir.

Animals↗

PubMed1995

Origin and immunoregulation of autoantibodies against intestinal alkaline phosphatase.

In the sera of patients with acute bacterial infections specific autoantibodies (sIAPa) of the immunoglobulin class G (IgG) were found which bind to intestinal alkaline phosphatase (IAP) through the Fab portion. This was demonstrated using immunoaffinity (IA) isolation of sIAPa from patients' sera (particularly bacterial meningitis and ventriculitis) digestion with pepsin, purification of F(ab')2 fragments on protein A and subsequently binding on IAP coupled to CNBr (cyanogen bromide)-activated Sepharose. Immunoblots using specific anti-Fc and anti-Fab antibodies showed that the bulk of F(ab')2 fragments had bound. Additionally, binding of native IAP to the F(ab')2 fragments was observed after separation of F(ab')2 fragments using isoelectric focusing (IEF), blotting onto nitrocellulose and incubation with IAP. Moreover, we have demonstrated the occurrence of natural anti-IAP autoantibodies (nIAPa) which were isolated from sera of healthy individuals using IA chromatography. Investigation of isotype distribution revealed that IgG but not IgM or IgA were predominant even among nIAPa. The nIAPa fraction exhibited lower binding efficiencies on IEF blots than the sIAPa fraction, however, in contrast to sIAPa, cross-reactions with other autoantigens were observed for nIAPa. NIAPa and sIAPa did not show subclass restriction. As revealed by IEF the spectrotypes of sIAPa were found to be patient-specific, poly- to oligoclonal and stable during longer periods.

Acute Disease↗