Biomedical subjects

K Pierer

Publications and source records attributed to K Pierer.

At least 19 recordsLinked to original sources

PubMed1999

Is IgM of diagnostic value in case of delayed intrathecal production of IgG antibodies?

The neurological manifestations of Lyme borreliosis comprise a wide range of clinical signs. However, these symptoms might have other aetiologies. Therefore detection of intrathecal production of specific antibodies is necessary to confirm the clinical assumption of neuroborreliosis (NB). In case of delayed intrathecal production of specific IgG antibodies, detection of IgM could play a role in the early diagnosis of NB. To clarify whether IgM is of diagnostic value in such cases, paired CSF serum samples from 176 patients with suspected NB admitted to the department of Neurology, Karl Franzens University, Graz, Austria, were tested. Testing was performed with the IDEA Neuroborreliosis Kit (Dako, Denmark) and Enzygnost Borreliosis (Behring, Germany) and results of both methods were compared. According to well defined criteria 63 of the 176 patients had defined NB and 113 were regarded as possible NB. Twelve out of 63 patients with defined NB had delayed intrathecal IgG production. Only one patient with delayed IgG production had an intrathecal IgM production prior to IgG. In all patients with possible NB no intrathecal production of IgM was detected. At the time of the first lumbar puncture IgG intrathecal production could be detected with the IDEA seven times more often than with the Enzygnost Borreliosis. The determination of intrathecal production of IgM does not appear to be of diagnostic value in patients with delayed IgG antibody production. Therefore a consecutive lumbar puncture is more likely to confirm clinical assumption if there is strong clinical evidence of NB.

Adult↗

PubMed1999

Species identification of Borrelia burgdorferi sensu lato from tick and human isolates in Styria (Austria) by PCR-RFLP analysis.

Seventy-one isolates of Borrelia burgdorferi sensu lato (B.b.s.l.) derived from Ixodes ricinus ticks (50 strains) and patients (21 strains) were characterised by PCR-RLFP analysis. In four cases the human isolates were obtained from the cerebrospinal fluid (CSF) of patients with clinical symptoms of neuroborreliosis and in 17 cases from skin biopsies of patients with dermatological manifestation of Lyme borreliosis. Ixodes ricinus isolates originated from 14 localities in three regions (Mur valley, eastern and western Styria) in Styria. Thirty six strains of B.b.s.l. were isolated from nymphal ticks, nine strains from female and five strains from male ticks. Species identification of human isolates revealed three B. garinii and one B. afzelii isolates in CSF. In the PCR-RFLP analysis of 17 skin specimens a pattern for B. afzelii was found in ten cases, while six could be identified as B. garinii and one as a mixed infection of B. afzelii and B. garinii. Genetic characterisation of tick isolates resulted in 24 strains of B. afzelii (48%), 11 strains of B. garinii (40%) and 5 strains of B. burgdorferi s.st. (10%); one isolate showed a mixed infection of B. afzelii and B. garinii. Our findings indicate that B. afzelii and B. garinii predominate over B. burgdorferi s.str. in Ixodes ricinus ticks from Styria, which is similar to findings in neighbouring countries. This also reflects the occurrence of different pathogenic Borrelia strains in human samples.

Animals↗

PubMed1999

Evaluation of AMPLILINK software for the COBAS AMPLICOR system.

The use of AMPLILINK version 1.0 software was evaluated for the operation and control of one COBAS AMPLICOR instrument and for two COBAS AMPLICOR instruments run simultaneously to perform and detect nucleic acid amplification reactions. A total of 3,384 results were analyzed. The initial accuracy of the results was 99.91%. Three errors of omission of transfer of data from the COBAS AMPLICOR to the AMPLILINK system were observed. Two of these errors were from a single specimen, where both the analyte and internal control results were not transmitted. These errors did not interfere with the correctness of any other data. There were no interruptions of runs, and no data were mixed. AMPLILINK increased convenience, saved labor, and was found to be a very useful addition for clinical laboratories performing molecular-diagnostic procedures with the COBAS AMPLICOR system.

Evaluation Studies as Topic↗

PubMed1998

A simple and robust method for the complete dissociation of HIV-1 p24 and other antigens from immune complexes in serum and plasma samples.

Accuracy of antigen determination in human plasma samples is often adversely affected by immune complex formation between antigens (e.g., HIV-1 p24 protein) and specific antibodies. In this study we describe an optimized method for complete immune complex dissociation (ICD) in plasma. This method is based on heat denaturation of antibodies and utilizes a defined solution of sodium dodecyl sulfate (SDS) and diethylenetriaminepentaacetic acid (DTPA) as diluent. The efficiency of this procedure for ICD was compared with those of published methods, employing heat denaturation alone and acidification. Plasma samples from patients participating in anti-retroviral treatments and samples reconstituted in vitro were treated and analyzed in parallel. HIV-1 p24 antigen was determined by quantitative enzyme-linked immunosorbent assay (ELISA). In 312 samples from 97 patients, antigenemia was found in 44.9% when measured directly and in 87.2% after this treatment. In a subset of 56 samples, 21.4% tested positive prior to treatment, while after either novel treatment, heat denaturation or acidification, these samples tested positive in 80.4%, 62.5% and 60.7%, respectively. In 94% of cases viral RNA was detected. This improved procedure for ICD provides a reliable and convenient method for complete and accurate p24 antigen detection in human plasma and is applicable to commercially available test kits.

Antigen-Antibody Complex↗

PubMed1998

Evaluation of a new assay for HBV DNA quantitation in patients with chronic hepatitis B.

BACKGROUND: The Amplicor HBV Monitor Test for quantitative determination of serum hepatitis B virus (HBV) DNA has recently been introduced. This assay is based on PCR and a non-radioactive hybridization and detection system on microwell plates. OBJECTIVE: The performance of the Amplicor HBV Monitor Test was evaluated in a routine diagnostic laboratory. The Amplicor HBV Monoitor assay was compared to the Digene Hybrid Capture System HBV DNA assay for the quantitation of HBV in patient sera. STUDY DESIGN: Sensitivity and reproducibility were determined with 10-fold dilution series of two Eurohep HBV reference plasma specimens. Furthermore, 196 sera from 14 children with chronic HBV infection and interferon therapy were tested with both assays. RESULTS: The detection limit was found to be 10(3) copies/ml with the Amplicor PCR assay compared to 10(6) to 10(7) copies/ml with the Digene hybridization assay. Both assays were quasi-linear over the measurable ranges. The new PCR assay proved to be very reliable. With the Amplicor PCR assay, 26.2% of the HBV DNA-positive clinical samples were found between 10(3) and 10(7) copies/ml and all of them tested below the detection limit with the hybridization assay. CONCLUSION: The Amplicor HBV Monitor Test shows excellent sensitivity and provides a valuable tool for the detection of HBV DNA in serum. It can be used for recognizing those patients who might benefit from antiviral therapy, for evaluation of the efficacy of anti-HBV therapy, and for validation of blood products.

Child↗

PubMed1998

Prevalence of Borrelia burgdorferi s.I. in Ixodes ricinus ticks from Styria (Austria) and species identification by PCR-RFLP analysis.

A total of 1163 I. ricinus ticks were collected in 3 different regions (15 localities) in Styria (Austria) in June 1997 and examined for the presence of spirochetes by dark field microscopy. The mean infection rate was 20.8%. Among 310 adults, 24.2% were positive and among 853 nymphs, 19.6% were positive. All 15 collection areas were shown to harbour infected nymphs with a positivity rate ranging from 5.8% (3/52) to 32.1% (18/56). Isolation attempts in BSKII medium resulted in 29 isolates. Species identification by PCR-RFLP analysis revealed 16 strains of B. garinii, 10 strains of B. afzelii and 2 strains of B. burgdorferi s. s. One isolate showed a mixed population of B. garinii and B. afzelii. In two collection areas, all three major Borrelia species were shown to be present in the tick population.

Animals↗

PubMed1998

Automation of polymerase chain reaction-based systems for detection of hepatitis C virus RNA.

Polymerase chain reaction-based molecular assays are gaining increasing importance in the diagnosis and monitoring of infectious diseases. Over the past several years, the development and application of these techniques has initiated a revolution in the diagnosis and monitoring of hepatitis C infection. Presently, molecular assays are exclusively done in especially dedicated laboratories. Advances in automation will bring these technologies into routine diagnostic laboratories and will make them widely used.

Automation↗

PubMed1998

Quantitative detection of hepatitis B virus DNA with a new PCR assay.

The Amplicor HBV Monitor Test for quantitative detection of serum hepatitis B virus (HBV) DNA has recently been introduced. This assay is based on PCR and a non-radioactive hybridization and detection system on microwell plates. Evaluation in a routine diagnostic laboratory showed excellent sensitivity and adequate reproducibility; however, a more automated format would be desirable. The Amplicor HBV Monitor Test is useful for recognizing those patients who might benefit from antiviral treatment and for evaluation of the efficacy of anti-hepatitis B virus treatment.

DNA, Viral↗

PubMed1997

Detection of antichlamydial antibodies in tears: a diagnostic aid?

OBJECTIVES: The antibody response in sera and tears of 167 patients with suspected chlamydial conjunctivitis was compared with the antibody response in sera and tears of 45 patients with symptoms of urogenital chlamydial infection to discover whether and which type of antichlamydial antibody detected in tears may be of diagnostic help in chlamydial conjunctivitis. METHODS: Diagnosis was based on chlamydial antigen detection from the conjunctiva and urogenital tract, done by a direct immunofluorescence assay, McCoy cell culture, and polymerase chain reaction. Additionally, antichlamydial immunoglobulin A (IgA) and immunoglobulin G (IgG) were determined in sera and tears of all patients by an immunoperoxidase assay. RESULTS: Two hundred twelve patients were examined--167 with conjunctivitis, 45 with symptoms of urogenital chlamydial infection. Cell culture, direct immunofluorescence assay, and polymerase chain reaction brought identical results. Conjunctival specimens taken from 33 (20%) of the patients with conjunctivitis were Chlamydia antigen positive; specimens taken from 134 (80%) were negative. Antichlamydial antibodies were found in tears of 29 (88%) of the patients with conjunctivitis whose specimens were Chlamydia antigen positive. Fifty-four (40%) of the patients with conjunctivitis whose specimens were Chlamydia antigen negative had antichlamydial antibodies in their tears. Twenty-five patients with urethritis (56%) were Chlamydia antigen positive in urethral swabs; 20 (44%) were negative. Antichlamydial antibodies were found in the tears of eight (32%) of the Chlamydia antigen-positive and two (10%) of the Chlamydia antigen-negative patients with urethritis. In contrast to patients with conjunctivitis, findings for patients with urethritis always were negative for antichlamydial IgG in the tears. CONCLUSION: Antichlamydial antibodies in tears were seen significantly more often in patients with conjunctivitis than in those with urethritis (P < or = 0.05). Antichlamydial IgG was found only in tears of patients with conjunctivitis. Therefore, the authors conclude that the detection of antichlamydial IgG in the tears might be helpful for diagnosis in patients with suspected chlamydial conjunctivitis who have antigen-negative conjunctival swabs.

Adolescent↗

PubMed1997

Performance of the automated COBAS AMPLICOR system for the detection of hepatitis C virus RNA.

BACKGROUND: The COBAS AMPLICOR (CA) instrument for the amplification and detection steps of the AMPLICOR molecular diagnostic assays has recently been introduced. The system contains a single thermal cycler with two independently controlled heating/cooling blocks, a pipettor, a magnetic particle washer, a photometer and an incubator. OBJECTIVE: The performance of the CA instrument was evaluated in a routine diagnostic laboratory for the detection of hepatitis C virus (HCV) RNA. The new system was compared with the corresponding microwell plate assay (AMPLICOR HCV Test). STUDY DESIGN: Routine clinical sera (350) from hemodialysis patients and patients with chronic HCV infection and interferon therapy were studied. If discrepant results were obtained, both assays were repeated (specimen preparation, amplification and detection); in addition, the HCV copy number was determined with the AMPLICOR HCV MONITOR Test. RESULTS: There was a correlation between the CA HCV Test and the AMPLICOR HCV Test in 341 of 350 specimens (97%). After resolution of 9 discrepant results, the CA HCV Test gave a sensitivity of 97.8% and a specificity of 99.4%. The most common reason for discrepant results was a low HCV RNA copy number. CONCLUSION: The CA system was found to be a labor-saving, fast and reliable instrument for the amplification and detection steps of a RT-PCR molecular assay for detection of HCV RNA.

Flaviviridae Infections↗

PubMed1997

Rapid diagnosis of enterovirus infection by a new one-step reverse transcription-PCR assay.

The AMPLICOR Enterovirus Test was evaluated with 103 cerebrospinal fluid (CSF) specimens. Twenty-seven CSF specimens were culture positive. With the AMPLICOR test, enterovirus RNA was detected in 34 specimens. Compared with culture, the AMPLICOR test gave a sensitivity of 96.3% and a specificity of 100%. The sensitivity of culture was 79.4% in comparison with the AMPLICOR test.

Enterovirus↗

PubMed1997

Rapid detection of Mycoplasma pneumoniae by an assay based on PCR and probe hybridization in a nonradioactive microwell plate format.

A new molecular assay, based on a rapid DNA extraction protocol, PCR, and hybridization to a specific probe in a nonradioactive microwell plate format was used to detect Mycoplasma pneumoniae in bronchoalveolar fluid specimens. The sensitivity of the assay was determined to be 10 to 100 organisms with M. pneumoniae reference strains. Specificity testing with different bacteria capable of producing pneumonia showed no cross-reactivity. In a prospective study, bronchoalveolar lavage fluids obtained from patients with pneumonia were investigated with the PCR assay and compared to culture. Twelve positive samples were detected with the PCR assay. Seven of them were subsequently confirmed by culture. All patients with positive PCR results seroconverted. Application of the PCR assay described may lead to safe and early diagnosis of M. pneumoniae in patients with pneumonia.

Adolescent↗

PubMed1996

Evaluation of two nonculture antigen tests and three serotests for detection of anti-chlamydial antibodies in the diagnosis of ocular chlamydial infections.

BACKGROUND: Diagnosis of chlamydial conjuctivitis is difficult in chronic diseases because chlamydial elementary bodies are mostly undetectable in conjunctival scrapings by cell culture. We therefore compared two nonculture antigen tests and three different serotests for anti-chlamydial antibodies with McCoy cell culture, the "gold standard" of chlamydial diagnosis. Conjunctival scrapings and serum samples of 93 patients attending the outpatient eye clinic in Graz because of chronic follicular conjunctivitis were tested. METHODS: A total of 558 conjunctival scrapings and 93 serum samples were investigated. Chlamydial antigen detection was done by McCoy cell culture, polymerase chain reaction (PCR; Amplicor, Roche), and direct immunofluorescence assay (DFA; Microtrak, Syva). Antichlamydial IgA and IgG antibodies in the sera were detected by an immunoperoxidase assay (IPAzyme, Savyon) and two different enzyme-linked immunosorbent assays (SeroELISA, Savyon and rELISA, medac). RESULTS: Cell culture and PCR yielded identical results. The positivity rate for chlamydial conjunctivitis was 8.6% (8 of 93 patients). PCR proved most sensitive and most specific. IPAzyme was 75% sensitive for IgA and 100% for IgG; SeroELISA and rELISA were less sensitive. IPAzyme was 81% specific for IgA and 47.3% for IgG. SeroELISA and rELISA were less specific for IgA, but more specific for IgG. Post-test likelihood of disease was greatest in IPAzyme. CONCLUSIONS: PCR proved to be a good alternative to cell culture; DFA is useful for quick diagnosis. Genus-specific serotests cannot compete with chlamydial antigen detection. They differ in sensitivity and specificity because of the antigen type they present. They are still of only supportive value in cases where chlamydial antigen detection is not possible. Recently introduced species-specific antibody tests should be of greater value.

Adolescent↗

PubMed1996

Reversal of Borrelia burgdorferi associated dilated cardiomyopathy by antibiotic treatment?

It is suggested that Borrelia burgdorferi infection could be associated with dilated cardiomyopathy (IDC). Stanek et al. were able to cultivate Borrelia burgdorferi from myocardial biopsy tissue of a patient with longstanding dilated cardiomyopathy. Here we present a study in which we examined the effect of standard antibiotic treatment on the left ventricular ejection fraction (LVEF) in patients with dilated cardiomyopathy associated with Borrelia burgdorferi infection. In this study we assessed the serum (IgG, IgM Elisa) and history of 46 IDC patients with specific regard to Borrelia burgdorferi infection (mean LVEF 30.4 +/- 1.3%, measured by cardiac catheterization and echocardiography with the length-area-volume method). All 46 patients received standard treatment for dilated cardiomyopathy: ACE inhibitors, digitalis, and diuretics. Eleven (24%) patients showed positive serology and a history of Borrelia burgdorferi infection; nine of these also had a typical history of tick bite and erythema chronicum migrans (ECM) and/or other organ involvement, and two had no recollection of tick bite or ECM but showed other Borrelia burgdorferi-associated disorders (neuropathy, oligoarthritis). These 11 patients with Borrelia burgdorferi infection received standard antibiotic treatment with intravenous ceftriaxone 2 g bid for 14 days. Six (55%) recovered completely and showed a normal LVEF after 6 months, three (27%) improved their LVEF, and two (18%) did not improve at all. This amounts to nine (82%) patients with recovery/improvement in the Borrelia burgdorferi group. The 35 patients who did not show positive serology or a history of Borrelia burgdorferi infection did not receive antibiotic treatment. In this group without Borrelia burgdorferi infection 12 (26%), showed recovery/improvement following the standard treatment of dilated cardiomyopathy (see earlier). Our results indicate that Borrelia burgdorferi infection could play a decisive role in the development of dilated cardiomyopathy, especially in a geographical region such as Graz, where Borrelia burgdorferi is endemic. While we are aware of the small number of Borrelia burgdorferi patients in this study, we nevertheless conclude that in a remarkable number of patients with signs of Borrelia burgdorferi infection, dilated cardiomyopathy could be reversed and LVEF improved.

Adolescent↗

PubMed1994

Comparison of two hybridization assays for the rapid detection of PCR amplified HSV genome sequences from cerebrospinal fluid.

Rapid diagnosis of herpes simplex encephalitis (HSE) can only be achieved by the polymerase chain reaction (PCR). In order to carry out PCR under routine conditions, it is of great importance to establish an easy DNA extraction protocol and especially a rapid and sensitive DNA detection method. In the present study, two different solid phase hybridization assays (Gen-Eti-K-DNA Enzyme Immunoassay (DEIA), Sorin Biomedica, Italy and Enzymun-Test DNA detection, Boehringer Mannheim, Germany) were compared for detection of PCR amplified HSV DNA polymerase genome region, using standard primers, from cerebrospinal fluid (CSF) samples. 122 CSF samples obtained from patients suffering from encephalitis and hospitalized at the University Clinics of Frankfurt and Graz during the period January 1992 to July 1993 were tested. To ascertain the sensitivity of the hybridization assays, dilution series of a plasmid, encoding the amplified region of the polymerase gene, were investigated. The detection limit of the DEIA assay was one copy of the plasmid/microliter, and the lowest amount of DNA which could be detected by the Enzymun assay as well as Southern blot was 10 copies/microliter. 15 CSF samples obtained from patients with HSE were found positive by the three assays. Concordant results were also obtained with CSF samples from non-HSE patients. The results of this study show that new hybridization systems guarantee a fast and high-sensitive detection of amplified HSV DNA. HSV PCR in CSF can be carried out routinely by the combined use of rapid hybridization and a simple extraction procedure.

Base Sequence↗

PubMed1994

Detection of herpes simplex virus DNA from cerebrospinal fluid by PCR and a rapid, nonradioactive hybridization technique.

A molecular assay for the detection of herpes simplex virus (HSV), including a novel, nonradioactive hybridization technique, was evaluated with a total of 123 cerebrospinal fluid specimens. After DNA extraction, specific HSV DNA sequences were amplified with digoxigenin-labeled primers derived from the DNA polymerase gene-coding region from HSV. Amplified products were detected by the Enzymun-Test DNA detection assay (Boehringer, Mannheim, Federal Republic of Germany), which uses biotinylated probes. Amplification with nonlabeled primers and then Southern blotting and nonradioactive detection of hybrids by the digoxigenin technique was the reference system. The sensitivities of the molecular assays were determined with 10-fold dilutions of plasmid pS4 with the SalI restriction fragment of the DNA polymerase gene obtained from the HSV type 1 strain Angelotti. The Enzymun assay was able to detect all of the 16 positive samples, giving 100% agreement with the Southern blot hybridization results. Optical density values were widely separated for the positive and negative groups of specimens. Ten copies of plasmid pS4 per microliter could be distinctly detected by the Enzymun assay. The cutoff was determined for the hybridization assay, and an equivocal zone was defined. The whole molecular assay including the Enzymun-Test DNA detection proved to be sensitive and easy to use. It may contribute to the rapid and safe detection of HSV DNA in cerebrospinal fluid.

Artifacts↗

PubMed1993

Prevalence of antibodies to Borrelia burgdorferi flagellin in Styrian blood donors.

Lyme borreliosis and tick-borne encephalitis (TBE) are the most common diseases in Austria caused by tick bites. TBE endemic areas are well defined. It seemed to be of interest to compare prevalence data of antibodies against Borrelia burgdorferi (B.b.) to TBE endemic and non endemic areas. Blood samples (n = 1162) were obtained from healthy blood donors in combination with a standardized questionnaire during 21 excursions to 7 selected regions of Styria, Austria. Serum samples were screened for IgG antibodies against B.b. by a commercial flagellum ELISA. None of the tested persons showed symptoms of active Lyme borreliosis. A higher prevalence of antibodies against B.b. could be found in TBE endemic areas (7.7%) compared to TBE nonendemic areas (3.8%). There was a significant increase in positive antibodies against B.b. with age, exposure and number of tick bites remembered by test persons. The antibody prevalence to B.b. flagellin antigen is significantly higher in TBE endemic areas than in non-endemic comparative regions.

Adolescent↗

PubMed1993

Rapid detection of Legionella species in bronchoalveolar lavage fluids with the EnviroAmp Legionella PCR amplification and detection kit.

A molecular assay based on a rapid DNA extraction protocol and the EnviroAmp Legionella Kits was used to detect Legionella species in bronchoalveolar fluid specimens. All Legionella strains isolated from tap water in hospitals could be detected distinctly. Both sensitivity and specificity were tested. In a prospective study, bronchoalveolar lavage fluids obtained from patients with atypical pneumonia were investigated. Three positive samples were detected with the molecular techniques and were subsequently confirmed by culture. Application of the system described may lead to safe and early diagnosis of Legionnaires' disease in patients with atypical pneumonia.

Bacteriological Techniques↗