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Biomedical subjects

K Felgenhauer

Publications and source records attributed to K Felgenhauer.

At least 55 records · Page 3Linked to original sources
PubMed1993

Purification and N-terminal sequence of beta-trace, a protein abundant in human cerebrospinal fluid.

beta-Trace, a protein that represents a major constituent of human cerebrospinal fluid with unknown function has been purified to apparent homogeneity by gel chromatography and electrophoresis. After sodium dodecylsulfate electrophoresis on polyacrylamide gels (SDS-PAGE) and Western blotting, the N-terminal sequence (28 amino acids) has been determined. The high degree of identity with the corresponding sequences of prostaglandin D synthetase from rat (68%) and human (93%) suggests a strong relationship if not identity with this enzyme. Thus, 30 years after its discovery beta-trace might unravel as a well-known protein of the prostaglandin metabolism.

Amino Acid Sequence↗
PubMed1993

An efficient sandwich-ELISA for the determination of choline acetyltransferase.

A specific, sensitive, and reliable sandwich-ELISA (enzyme-linked immunosorbent assay) has been established for the determination of choline acetyltransferase (CHAT) from porcine brain. The detection limit of the assay was 30 micrograms/l and the assay was linear up to 300 micrograms/l. The within-day and day-to-day coefficients of variation were found to be 3.3% and 4.7% respectively for low CHAT concentrations (30 micrograms/l) and 3.1% and 3.4% respectively for high levels of CHAT (300 micrograms/l). The immunoassay was more sensitive than the radiometric assay of Fonnum which is widely used for the measurement of enzyme activity. In the assay monoclonal antibody was adsorbed to the polystyrene surface of the immunoplate as the capture reagent. Using a standard peroxidase protocol the immobilized antigen was detected with a highly specific anti-CHAT antiserum raised in rabbits. Two monoclonal antibodies were available for antigen binding. One of the two--A10.29B4--reacted preferentially with the active enzyme the other one--B3.9B3--reacted only with a degraded form. The polyclonal antiserum recognized both native and denatured enzyme. The effectiveness of employing the two monoclonal antibodies separately or in combination was demonstrated by measurement of porcine CHAT diluted in human cerebrospinal fluid and serum. After some minor modifications the sandwich-ELISA could be used for the determination of CHAT from the central nervous system of the rat.

Animals↗
PubMed1993

Soluble intercellular adhesion molecule-1 in cerebrospinal fluid: an indicator for the inflammatory impairment of the blood-cerebrospinal fluid barrier.

A soluble form of the intercellular adhesion molecule-1 (sICAM-1) was measured in paired cerebrospinal fluid (CSF)/blood samples from 123 patients with different neurological diseases. Mean levels of circulating ICAM-1 in the blood were mean +/- SD = 423 +/- 184.6 ng ml-1 (range 44-1115 ng ml-1). Considerable differences of sICAM-1 in the CSF of patients were observed between disease groups. In acute bacterial meningitis, sICAM-1 levels as high as 1/5 of the serum concentration were detected in the CSF (n = 24; mean +/- SD = 33.0 +/- 23.7 ng ml-1; range: 4.8-93.9 ng ml-1). These changes coincided with a severe blood-CSF barrier dysfunction as indicated by a high CSF/blood ratio for albumin (mean +/- SD = 46.7 +/- 52.2; range: 16.8-249.3). In patients with polyradiculitis (n = 9; mean +/- SD = 14.5 +/- 11.9 ng ml-1; range: 2.6-43.7 ng ml-1) a similar covariation between the albumin and sICAM CSF/blood ratios was detected. In patients with multiple sclerosis (n = 9; mean +/- SD = 5 +/- 4.3; range: 0-12.7 ng ml-1) or HIV infection with neurological symptoms (n = 18; mean +/- SD = 4.9 +/- 3.2; range; 1-11.9 ng ml-1) low levels of sICAM-1 were detected in the CSF associated with intact blood-CSF barrier function in most patients. Among 13 patients with viral meningitis, only four had detectable levels of sICAM-1 in their CSF (mean +/- SD = 1.0 +/- 1.5 ng ml-1; range: 0-3.7).(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, CD↗
PubMed1993

Antibodies raised against synthetic peptides react with choline acetyltransferase in various immunoassays and in immunohistochemistry.

Antisera were raised in rabbits against five synthetic peptides. These peptides have been identified as potentially antigenic epitopes from the sequence of porcine choline acetyltransferase (ChAT) using primary and secondary structure analysis. All five antisera recognized immunoaffinity-purified antigen from porcine brain in an ELISA and on western blots. Four antisera recognized ChAT on dot blots, and another four antisera reacted with native and degraded enzyme in a sandwich ELISA using monoclonal antibodies as the capture antibody. One peptide antiserum was of similar avidity in this sandwich ELISA as a polyclonal antibody raised against immunoaffinity-purified ChAT. The same antiserum reacted with the enzyme from human placenta in an ELISA and on western and dot blots and recognized ChAT in rat, primate, and human neurons. Thus, a single peptide (amino acids 168-189) provides the means for easy, reliable, and reproducible generation of antibodies against ChAT suitable for replacing conventional polyclonal and monoclonal antibodies.

Animals↗
PubMed1992

The diagnostic significance of antibody specificity indices in multiple sclerosis and herpes virus induced diseases of the nervous system.

The antibody specificity index (ASI) indicates the cerebrospinal fluid (CSF)/serum difference of antibody amounts per weight unit IgG (normal less than 1.5). It has proven to be the most sensitive inflammation parameter in CSF analysis so far, more sensitive than the Western blot, the "oligoclonal" response, and the empirical differentiation of CSF immunoglobulins. By this diagnostic criterion, several benign viral meningitis cases were found to be caused by the varicella/zoster virus. The diagnostic relevance of local zoster antibody synthesis was greatest in ganglionitis cases, e.g., in zoster oticus sine herpete (facial paresis) and acute radicular syndromes of the elderly. The diagnostic significance of the local immune response against measles, rubella, and zoster antigens (MRZ response) was ascertained further. Together with oligoclonal gamma-globulin fractionation, there is now only 1 out of 100 multiple sclerosis (MS) patients left who has been found to have a normal CSF.

Adult↗
PubMed1992

Specific antigen binding by activated cerebrospinal fluid B lymphocytes in acute neuroborreliosis.

A recently developed immunocytochemical antigen-binding sandwich test for the identification of specific activated B lymphocytes was applied to cerebrospinal fluid cells and peripheral blood mononuclear cells in patients with acute neuroborreliosis. Discrimination of antigen-binding phagocytes was achieved by double staining with monoclonal antibodies. Specific activated B lymphocytes were much more numerous in cerebrospinal fluid than in blood, showing great interindividual differences. When intrathecal immunoglobulin production was present, the number of specific activated B lymphocytes was also high. The specificity of all activated B lymphocytes ranged from 10% to 60% and was higher in the acute stage than after treatment.

Acute Disease↗
PubMed1992

Characterization of mono- and polyclonal antibodies against highly purified choline acetyltransferase: a monoclonal antibody shows reactivity in human brain.

Choline acetyltransferase (ChAT) from porcine brain was purified by immunoaffinity chromatography, and the highly purified enzyme was subsequently used for immunization of mice and rabbits. After fusion of mouse spleen cells, 32 cultures producing monoclonal antibodies directed against ChAT were detected by an enzyme-linked immunosorbent assay (ELISA) with immunoaffinity-purified ChAT. Of these original 32, the most active 11 cultures were cloned and used for ascites production. The 11 clones generated monoclonal antibodies of the immunoglobulin (Ig) M class (three), the IgG1 subclass (seven), and the IgG2b subclass (one). The isoelectric points of the antibodies of the IgG class were different in each case. The monoclonal antibodies exhibited different binding characteristics in the above ELISA and on western blots. Two monoclonal antibodies demonstrated excellent immunohistological results with neurons of rat brain and spinal cord. One of them reacted well immunohistochemically with neurons of human brain and also recognized partially purified human placenta ChAT in the ELISA.

Animals↗
PubMed1992

Acute demyelinating disease. Classification and non-invasive diagnosis.

Five young patients are described with biopsy-proven acute demyelinating disease. Two cases are classified as Schilder's disease, a particular childhood form of multiple sclerosis (MS) with atypical clinical manifestation, normal or atypical CSF-findings and large bilateral lesions in magnetic resonance imaging (MRI). Two further cases presented with a fulminant bout of MS with typical clinical picture and CSF-findings; they are classified as Marburg's disease. The last case was an acute second bout of classical MS. The biopsy seemed to be justified in 4 cases, but unnecessary in the last case. Localized proton magnetic resonance spectroscopy (MRS) performed in one case allowed us to examine the focal cerebral abnormalities directly and non-invasively. The spectra revealed a pattern typical of acute demyelination suggesting potential for a replacement of biopsy in the future.

Adult↗
PubMed1992

IgA producing primary intracerebral lymphoma.

The first case of a primary and solitary IgA (lambda) producing tumour (possibly a non-Hodgkin's lymphoma) in the CNS is reported. Clinical and neuroimaging findings are described. Early diagnosis without brain biopsy and successful therapy were possible by CSF and serum immunoglobulin analysis which proved local paraprotein production restricted to the CNS.

Adrenal Cortex Hormones↗
PubMed1991

Clinical relevance of the quantification of apolipoprotein E in cerebrospinal fluid.

Apolipoprotein E was measured in paired sera and cerebrospinal fluid samples from 483 neurological patients. The average apolipoprotein E concentration was 7.5 (+/- 3.1) mg/l in cerebrospinal fluid and 93.5 (+/- 29.7) mg/l in serum. Mean apolipoprotein B concentrations in 88 patients were 0.77 +/- 3.4 mg/l in cerebrospinal fluid and 1.06 +/- 0.31 g/l in serum. The apolipoprotein E concentration in cerebrospinal fluid was much greater than expected for passive diffusion from serum. By contrast to apolipoprotein B, there was no correlation between the apolipoprotein E cerebrospinal fluid/serum concentration quotient and the albumin concentration quotient. This suggests that apolipoprotein E in cerebrospinal fluid, unlike apolipoprotein B, is locally synthesized and that the use of a cerebrospinal fluid/serum concentration quotient is unnecessary. In a control group (n = 64) the mean cerebrospinal fluid apolipoprotein E value (+/- SD) was 5.9 (1.6) mg/l. Elevated cerebrospinal fluid apolipoprotein E concentrations were observed in acute (n = 22, 12.5 +/- 6.2 mg/l) and chronic inflammatory central nervous system diseases (n = 15, 10.4 +/- 2.4 mg/l).

Adult↗
PubMed1991

The use of recombinant antigens in ELISA procedures for the quantification of intrathecally produced HIV-1-specific antibodies.

An ELISA procedure is described for the quantification of intrathecally synthesized immunoglobulin G antibodies to human immunodeficiency virus (HIV) antigens. Recombinant p17, p24, endonuclease (END), reverse transcriptase (RT), a peptide from the transmembrane region of gp41 (ENV80) and a fusion protein containing HIV-1 and HIV-2 epitopes were compared with a commercially available ELISA. Using a reference serum, antibodies in serum and cerebrospinal fluid (CSF) to all of the antigens could be measured quantitatively in a reliable and reproducible fashion. Despite the fact that the titer varied up to 10(5)-fold between CSF and serum, interassay variability ranged from 3.87% for p17 to 8.41% for RT and intra-assay variability varied from 3.9% +/- 1.2% for p17 to 14.3% +/- 3.9% for the commercial ELISA. Antibody specificity indices (ASI) obtained by relating CSF/serum titers with reference to the corresponding IgG concentrations can be used to detect intrathecal synthesis of virus specific antibodies.

Enzyme-Linked Immunosorbent Assay↗
PubMed1991

The proliferation rate of T and B lymphocytes in cerebrospinal fluid.

An immunocytochemical method is presented by which individual proliferating T and B lymphocytes can be detected in the cerebrospinal fluid (CSF) of patients with inflammatory and neoplastic diseases of the central nervous system. The absolute numbers of proliferating T and B lymphocytes were approximately equal, so that only a minority of the strongly prevailing T-cell population proliferates in the CSF during the immune process. The highest proliferation (25.7%) was found within the small subset of activated, i.e. cytoplasmic immunoglobulin-containing, B lymphocytes. This provides further evidence that these cells are not the terminally differentiated plasma cells of classical cytology but progenitor cells capable of further proliferation. B-cell lymphomas could be easily identified. The detection of abnormally proliferating cell subsets could help in the differentiation of opportunistic infection from leukaemic infiltration.

B-Lymphocytes↗
PubMed1991

Immunoblot for densitometric estimation of antibodies (IDEA): a useful method for quantification of intrathecally produced antibodies against individual antigens in infectious diseases of the central nervous system.

Intrathecally produced antibodies specific for the infectious agent can be shown by immunoblot. A quantification is practicable by titration. Densitometric evaluation of the immunoblot by a new technique, IDEA (immunoblot for densitometric estimation of antibodies), does not only render titration unnecessary, but also has the advantage of presenting the differentiated local immune response against individual antigens of the infectious agent. Preliminary studies for the densitometric evaluation were performed with a measles virus immunoblot which had been developed with a cerebrospinal fluid (CSF) sample of a patient suffering from multiple sclerosis containing high antibody titers. A peroxidase-labeled anti-immunoglobulin antibody had been added. The intensity of the color reaction on the membrane dependent on the antibody concentration follows a saturation kinetics comparable to the Michaelis-Menten kinetics in enzymology. Thus, indices for the intrathecal antibody synthesis of each individual viral antigen can be calculated by taking the permeability of the blood-CSF barrier into consideration. This method is illustrated in a patient with zoster meningoencephalitis.

Antibodies, Viral↗
PubMed1991

Neuronal acetylcholinesterase levels in cerebrospinal fluid and serum determined by a specific and sensitive immunoassay.

Acetylcholinesterase levels were determined in cerebrospinal fluid and serum of 272 patients with various neurological disorders. The patients were ordered in 13 diagnostic groups. The assay employed was an antigen capture assay based on an immobilized monoclonal antibody selective for neuronal acetylcholinesterase (Rasmussen et al., Clin. Chim. Acta 166 (1987) 17-25 (1)). In 100% of the cases the acetylcholinesterase levels in cerebrospinal fluid were 500-10,000 fold higher than expected for a regular serum-derived protein (0.1-0.5%) at the intact blood-brain barrier. In both compartments the test values showed wide variations, which were much greater in serum than in cerebrospinal fluid. No specific relationship was discernible between the values obtained and any of the diagnostic groups, although decreased levels of acetylcholinesterase were found in bacterial and viral meningitis, and elevated levels were found in groups with more chronic diseases. A possible transfer of acetylcholinesterase from cerebrospinal fluid to blood is discussed.

Acetylcholinesterase↗
PubMed1991

A cationic glycoprotein pattern in human serum and cerebrospinal fluid with pathological implications.

Patterns of highly glycosylated proteins with mainly cationic isoelectric points, pH 6.5-9.5, were observed in serum and cerebrospinal fluid of patients with various disorders. Detection was performed after isoelectric focusing, using an immunoassay specific for digoxigenylated carbohydrate moieties of glycoconjugates. To our knowledge, these glycoproteins have not hitherto been described as regular serum proteins. The patterns were found among 7% of the patients studied (n = 400). Similar bands were not detectable in a reference group of 100 persons without clinical symptoms. The glycoprotein pattern was specific for each individual. The pathophysiological meaning of these glycoproteins as well as the basic biochemistry has not yet been evaluated. The glycoproteins, however, were shown to differ from immunoglobulin G, oligoclonal immunoglobulin G, paraprotein or from regular cationic serum protein. By comparison with standard glycoproteins a carbohydrate content of 30 +/- 10% was roughly suggested. The oligosaccharides contain probably sialic acid as evidenced by lectin binding. Although the diagnoses varied, 90% of the patients with this glycoprotein pattern had inflammatory processes.

Blotting, Western↗