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Biomedical subjects

W Bossart

Publications and source records attributed to W Bossart.

At least 19 recordsLinked to original sources
PubMed1999

Two-centre study comparing DNA preparation and PCR amplification protocols for herpes simplex virus detection in cerebrospinal fluids of patients with suspected herpes simplex encephalitis.

In a two-centre study, the routine DNA preparation and PCR amplification protocols were compared for herpes simplex virus (HSV) detection in cerebrospinal fluids (CSFs) of 43 patients with suspected herpes simplex encephalitis (HSE). The combined clinical, radiological and laboratory results indicated HSE in 6/43 (14%) patients. Discrepant PCR results between the two centres were obtained in 8 (18%) cases consisting of 5 false-positive and 3 false-negative results. Seven out of 8 (88%) discrepant results were associated with the method of CSF preparation using protease K digestion followed by heat inactivation. In contrast, CSF digestion with proteinase K followed by DNA purification on silica spin columns was better yielding discrepant PCR results in only 1 of 78 analyses (1.3%). The results point to the need for standardization and inter-laboratory quality control for routine clinical work.

DNA, Viral↗
PubMed1999

Detection and quantification of cell-free Epstein-Barr virus by polymerase chain reaction and subsequent DNA enzyme immunoassay.

Amplification by polymerase chain reaction and subsequent DNA enzyme immunoassay (DEIA) were employed to determine the number of genome equivalents of cell-free Epstein Barr virus (EBV) DNA in peripheral blood. The assay detected cell-free EBV DNA in the serum of 14 out of 18 patients with primary, productive EBV infection (sensitivity 77.7%) but not in healthy EBV carriers with latent infection (specificity 100%). Our assay has the potential for a clinical diagnostic tool to monitor patients at risk for EBV reactivation and productive infection with subsequent EBV-induced lymphoproliferative diseases.

Base Sequence↗
PubMed1998

[Clinical evaluation of impression cytology in diagnosis of superficial viral infections].

BACKGROUND: Impression cytology is a non invasive technique for the diagnosis of external eye disease. As infected epithelial cells are losing their adhesion to neighbouring cells they are an ideal target for impression cytology. Despite its diagnostic potential impression cytology has not yet become a routine diagnostic tool because of technical inconvenience in use of conventional membranes. The aim of this study was to evaluate a practicable technique of impression cytology for the rapid diagnosis of superficial viral eye disease. MATERIAL AND METHODS: 52 patients with suspected viral conjunctivitis or keratitis underwent impression cytology with a Biopore membrane device. After air fixation immunologic detection tests using either peroxidase antiperoxidase or fluorescent techniques were performed directly on the membrane. RESULTS AND CONCLUSIONS: 21 of 38 patients with suspected Herpes-simplex-virus (HSV), 3 of 4 patients with suspected Varicella-Zoster-virus (VZV) and 2 of 10 patients with suspected Adenovirus infection had a positive result on the impression cytology membrane. These results were confirmed by virus cultures or polymerase chain reactions (PCR) a few days later. No patient with a negative impression cytology had a positive culture result. Using impression cytology and an immunodetection test results became available within 1 to 4 hours. CONCLUSIONS: Impression cytology combined with immunologic detection tests is a rapid, sensitive and practicable diagnostic test for superficial viral eye diseases.

Adenovirus Infections, Human↗
PubMed1997

Surveillance of cytomegalovirus after solid-organ transplantation: comparison of pp65 antigenemia assay with a quantitative DNA hybridization assay.

In a multicenter study, 113 blood samples from 19 organ transplant patients were analyzed for cytomegalovirus by the pp65 antigenemia assay and a quantitative DNA hybridization assay. Overall, there was 84% agreement among the results obtained by the two tests. Fifteen of 16 episodes of active infection were detected by both assays. One episode was missed by the pp65 assay, and one patient showed significant DNA-emia but only low-level antigenemia.

Antigens, Viral↗
PubMed1997

Improved impression cytology techniques for the immunopathological diagnosis of superficial viral infections.

BACKGROUND: For epidemiological and therapeutic reasons early diagnosis of superficial viral infections is crucial. Conventional microbiological techniques are expensive, time consuming, and not sufficiently sensitive. In this study impression cytology techniques were evaluated to analyse their diagnostic potential in viral infections of the ocular surface. METHOD: A Biopore membrane device instead of the original impression cytology technique was used to allow better quality and handling of the specimens. The impressions were processed, using monoclonal antibodies and immunoperoxidase or immunofluorescence techniques to assess the presence of herpes simplex virus, varicella zoster virus, or adenovirus antigens. Ocular surface specimens from healthy individuals (n = 10) and from patients with suspected viral surface disease (n = 19) were studied. Infected and non-infected cell cultures served as controls. RESULTS: This modified technique of impression cytology allowed the collection of large conjunctival and corneal epithelial cell layers with excellent morphology. Immunocytological staining of these samples provided diagnostic results for all three viruses in patients with viral surface disease. CONCLUSIONS: The use of Biopore membrane devices for the collection of ocular surface epithelia offers new diagnostic possibilities for external eye diseases. Immunopathological methods that are applied directly on these membrane devices can provide virological results within 1-4 hours. This contributes considerably to the clinical management of patients with infectious diseases of the ocular surface.

Antigens, Viral↗
PubMed1996

[Fever and headache].

A 30-year-old male patient was admitted to our outpatient clinic because of fever, headache and cerebellar symptoms. Clinically he presented with a slight meningism. After exclusion of a focal intracerebral process by head scanning, a first diagnosis of an aseptic meningitis was made by the analysis of the cerebrospinal fluid. With the hint of repeated tick bites, the diagnosis of an early-summer meningoencephalitis was confirmed. The patient recovered without neurological residua within two months. The clinical course, dates of new epidemiologic studies and problems of vaccination are discussed.

Adult↗
PubMed1996

Severe tick-borne encephalitis following passive immunization.

UNLABELLED: We report on a 5-year-old girl with an unusually severe course of tick-borne encephalitis following passive immunization with specific hyperimmune globulin after a tick bite in an endemic area. Serial investigations of the CSF revealed intrathecal production of specific antibodies paralleled by increasing numbers of B-cells after initial T-cell pleocytosis. Focal central lesions were evident on MRI. CONCLUSION: The severity of the presented case questions the benefit of passive immunization and rather justifies consideration of vaccine recommendation to residents and travellers to areas endemic for tick-borne encephalitis virus.

Child, Preschool↗
PubMed1992

Protection by a polyvalent vaccine against challenge infection and pyelonephritis.

The protective effect of immunization with a polyvalent vaccine (SolcoUrovac) was studied in the mouse and the rat. The i.m. immunization increased the resistance of mice to challenge infection with all homologous strains of bacteria. The LD50 values for E. coli, Proteus mirabilis and Streptococcus were 3.5-4.5 times and that of Klebsiella as much as 600 times that in nonimmunized mice. Protection against challenge with heterologous E. coli was also achieved and persisted for about 20 weeks. Immunization with the vaccine also provided marked protection against pyelonephritis in rats. Kidneys with abscesses were seen only one-third as often as in controls, and the size of the individual abscesses was substantially smaller in the vaccinated animals. Based on the quantity of bacteria in the kidneys it was postulated that the vaccination increased the clearance of bacteria.

Abscess↗
PubMed1992

[The effect of Lactobacillus acidophilus "Solco" on the immunological indices of totally decontaminated mice under complete gnotobiological isolation].

The possibility of stimulating the immunity of totally decontaminated mice, kept isolated under germ-free conditions, with the use of killed L. acidophilus Solco strains has been studied. As revealed in this study, the oral and intraperitoneal administration of strains O1 and O6 to mice leads to a significant increase in the content of immunoglobulin-synthesizing cells in the jejunal lamina propria of the animals. The oral administration of L. acidophilus Solco strain O6 and the intraperitoneal injection of L. acidophilus Solco strain O1 have been found to lead to a significant rise in the level of luminol-dependent chemiluminescence of mouse peritoneal macrophages. The total decontamination of mice induces the development of secondary immunodeficiency which influences the effectiveness of immunostimulating agents.

Animals↗
PubMed1989

Urinary antibody response after immunisation with a vaccine against urinary tract infection.

Immunisation of mice with SolcoUrovac vaccine induced an approximately 10-fold increase of the total amount of IgG and a 2-fold increase of IgA immunoglobulins in urine. IgG antibodies to SolcoUrovac antigens appeared in urine after the first injection, and booster injections caused a further increase of the titer. IgA antibodies appeared in the urine after the second injection, and the third injection doubled the titer. IgM immunoglobulins and specific IgM class antibodies to SolcoUrovac were not found in any urine tested. The exact origin of the immunoglobulins in the urine as well as the specificity of immune response is discussed.

Adjuvants, Immunologic↗
PubMed1984

Accumulation of poliovirus proteins in uninfected isolated HEp-2 cell nuclei in vitro.

Poliovirus (type 1, Mahoney) proteins preferentially inhibited in vitro RNA polymerase II activity in uninfected isolated HEp-2 cell nuclei, as demonstrated by electron microscopic autoradiography. Structural integrity of the nuclei and preincubation of nuclei and poliovirus proteins in vitro prior to addition of [3H]-UTP were prerequisites for differential inhibition. During in vitro incubation, [3H]-labeled poliovirus proteins were shown to accumulate in the uninfected isolated nuclei. Similar poliovirus proteins accumulated in the nuclei to higher relative amounts as compared to the outside or were excluded from the nuclei after in vitro incubation, as in intact poliovirus-infected cells. Since the in vitro transcription system of isolated nuclei exhibited two characteristics of poliovirus infection, i.e., preferential inhibition of RNA polymerase II activity and accumulation of poliovirus proteins in the nuclei, it may be useful to study host RNA synthesis inhibition.

Autoradiography↗
PubMed1983

Intracellular distribution of poliovirus proteins and the induction of virus-specific cytoplasmic structures.

In a susceptible cell, enteroviruses induce a vesiculated region (the "virus-induced vesicles") which is both the site of viral RNA synthesis as well as the site referred to morphologically, as the "cytopathic effect." Proteins of poliovirus (type I, Mahoney) were shown to migrate into the region of the virus-induced vesicles of infected HEp-2 cells. Five proteins (P2-5b, P3-4b, P3-6a, P3-7c, P3-9) were found to be associated with the vesicles themselves, either as intrinsic membrane protein (P3-9) or in a soluble form within the vesicles (P3-4b, P3-7c, and, partially, P3-6a) or bound to a DOC-resistant structure (P2-5b and a small amount of P3-6a). Partial inhibition of the cleavage of the viral polyprotein with ZnCl2 was used to alter the viral protein pattern within the cells. The data obtained indicate that P2-5b is the protein responsible for the formation of the virus-induced vesicles.

Carcinoma, Hepatocellular↗
PubMed1982

Poliovirus-induced inhibition of host RNA synthesis studied in isolated HEp-2 cell nuclei.

Nuclei isolated from uninfected HEp-2 cells synthesized RNA for 60 to 90 min. The individual RNA polymerase activities were determined by alpha-amanitin differential inhibition and the RNA products characterized by electron microscope (EM) autoradiography and sucrose gradient centrifugation. In nuclei prepared from poliovirus-infected cells, the capacity to synthesize RNA in vitro decreased with time after infection. RNA polymerase II activity (hnRNA synthesis) was preferentially inhibited more than was the polymerase I activity (rRNA synthesis). Poliovirus-infected cytoplasm (S-30) inhibited in vitro RNA synthesis in uninfected nuclei by selectively affecting the polymerase II activity. Selective inhibition of hnRNA synthesis by the crude extracts could be monitored by EM autoradiography directly. Determinations of individual RNA polymerase activities by differential alpha-amanitin inhibition were done only after treatment of the infected cytoplasm with micrococcal nuclease to abolish virus RNA replication. Selective inhibition of hnRNA synthesis depended on preincubation of the nuclei together with the infected cytoplasm, indicating that inhibitory substances from the infected cytoplasm entered the nuclei. Isolated nuclei therefore provide a useful system for studying the nature of the inhibitor(s) and of host RNA synthesis inhibition by picornaviruses.

Cell Line↗
PubMed1982

Accumulation of poliovirus proteins in the host cell nucleus.

Poliovirus (type 1, Mahoney) proteins were transported into the nuclei of HEp-2 cells, as demonstrated by means of electron microscopic autoradiography. Quantitative determinations of the proteins by electrophoresis showed that the relative amounts of precursor proteins (1a, 3b, 1b), of some of the intermediate polypeptides (3a, 3c, 5b, 2), and of one end product (VP1) were higher in the nucleus than in the cytoplasm. Other proteins (VPO, VP2, X, 4, 6a) were found in the same relative amounts in the nucleus as in the cytoplasm, whereas two proteins (VP3 and 6b) were excluded from the nucleus. The findings are discussed in view of the recently demonstrated inhibitory activity exerted by cytoplasmic extracts of poliovirus-infected cells on transcription in isolated nuclei of uninfected cells.

Cell Compartmentation↗