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Biomedical subjects

C Kunz

Publications and source records attributed to C Kunz.

At least 163 records · Page 9Linked to original sources
PubMed1988

[Viral nucleic acids in the serum of hepatitis B patients].

Detection of hepatitis B viral DNA (HBV-DNA) is the most reliable test for infectivity of a patient's serum. HBV-DNA was detected by spot hybridization on nylon membrane. HBV-DNA was detected during the first or second week of jaundice in 22/133 (16.5%) sera from patients with acute hepatitis who did not develop chronic disease later on. However, in patients with acute hepatitis who later on developed the chronic form, HBV-DNA was found in 12/12 (100%) cases in the first or second week after onset. In other patients who had chronic hepatitis for longer than one year HBV-DNA was detected in 92/113 (81.4%) sera when HBe antigen was also detectable and in 11/104 (10.6%) when HBe antibodies were found. HBV-DNA was present in 32/38 (84.2%) sera from healthy antigen carriers when HBe antigen was detected and only in 2/173 (1.2%) sera of HBe antibody positive HBs antigen carriers. The highest levels of HBV-DNA were found in patients with chronic hepatitis B infection who were found in patients with chronic hepatitis B infection who were on haemodialysis therapy. Almost all had HBe antigen and HBV-DNA was also detectable in 82/84 (97%) sera. 11/28 (39.3%) sera from patients with chronic hepatitis B as well as HIV infection showed HBV-DNA. Detection of HBV-DNA has significantly improved the accuracy of diagnosis of hepatitis B viral infection.

DNA, Viral↗
PubMed1988

Detection of cytomegalovirus in clinical specimens by virus isolation and by a monoclonal antibody against the early nuclear antigen.

A commercially available monoclonal antibody against the 72000 Dalton early nuclear protein (EA) of cytomegalovirus (CMV) strain AD169 was used in an indirect immunofluorescence staining procedure (IF) for rapid detection of CMV-infected cells in tissue cultures inoculated with clinical specimens (200 urines, 22 throat washings, 5 stools, 4 bronchoalveolar lavage fluids). The results obtained by this method were compared with those obtained by virus isolation with and without centrifugal enhancement of viral infectivity. In 66 (28.6%) of the 231 samples, CMV was detected by at least one of the methods used. Of 59 specimens producing CMV-specific cytopathic effect (CPE) in tissue culture, 46 (78%) were also positive in the EA test 16 hours after inoculation. Seven CPE-negative samples were, however, positive in the EA test. Five (38%) of the false negative EA test results were due to CMV strains that did not react with the monoclonal antibody used.

Antibodies, Monoclonal↗
PubMed1988

Contribution of rhinoviruses to respiratory viral infections in childhood: a prospective study in a mainly hospitalized infant population.

A prospective study was carried out to investigate the contribution of rhinoviruses to respiratory viral infections in children and to investigate the influence of age, passive smoking, and educational level of the head of the family on the clinical course of viral respiratory disease. Nasopharyngeal aspirates from 519 infants (90.8% inpatients, 9.2% outpatients) were screened for the presence of rhinoviruses, respiratory syncytial virus (RSV), adenoviruses, parainfluenza virus types 1, 2, 3, influenza virus types A and B, and enteroviruses by tissue culture isolation procedure, enzyme-linked immunosorbent assay, and/or indirect immunofluorescence method. The total detection rate was 42.4%. The rate decreased with increasing age. Higher detection rates were observed in specimens from children suffering from a more severe respiratory disease, and the highest rate of virus-positive specimens was found in those aged 0-6 months. Second to RSV (23.1%), rhinoviruses were the most frequently recovered pathogens found in 11.8% of children with acute respiratory tract infections (RTI). In the age group 0-6 months the majority of severe respiratory illnesses was due to RSV. In infants aged 6 months to 1 year a decrease in the number of severe illnesses caused by RSV and an increase in the number of children suffering from a more severe RTI caused by rhinoviruses was found. With the possible exception of one group of children infected with rhinoviruses, a negative effect of passive smoking on the incidence and severity of viral RTI could not be established. A beneficial effect of breast feeding on the severity of viral RTI could not be definitely demonstrated.

Austria↗
PubMed1988

Sequence of the structural proteins of tick-borne encephalitis virus (western subtype) and comparative analysis with other flaviviruses.

Tick-borne encephalitis (TBE) virus (Western subtype strain Neudoerfl) was cloned and the sequence of 2450 nucleotides of the 5'-terminal region of the genome was determined. By amino acid sequencing and sequence comparisons with other flaviviruses the amino-termini of the structural proteins and protein NS1 were localized. Sequence homologies with other flaviviruses were determined and corresponded well to the established serological classification system of the Flavivirus family. N-Glycosylation sites were found to be conserved to a large extent among members of the same serological subgroup, but not between members of different subgroups. Hydrophilicity plots and sequence comparisons revealed that the TBE virus capsid protein exhibited features distinct from all other flaviviruses. Additionally, the capsid protein coding region of another natural isolate of TBE virus (strain ZZ-9) was sequenced in order to analyze why the capsid protein of this strain exhibited a significantly faster migration rate on SDS-polyacrylamide gels than other TBE virus strains.

Amino Acid Sequence↗
PubMed1988

Application of a dot blot hybridization assay for the diagnosis of CMV infection or reactivation.

Dot blot hybridization was performed for the detection of cytomegalovirus (CMV) genomes in urine samples. This assay was applied to the diagnosis of CMV infection in transplant patients, who were tested continuously after transplantation and the results were compared to the detection of early antigen (EA) in fibroblasts inoculated with urine specimens as well as to serological methods. It turned out that discrepancies between EA-detection and dot blot hybridization are partially caused by the different appearance and disappearance of the two parameters at different time points. In most cases the dot blot hybridization assay proved to be an earlier marker than EA-detection in the course of infection. In several patients, however, hybridization showed positive signals although there was no sign for a productive CMV infection.

Antigens, Surface↗
PubMed1988

Humoral regulation of the orthostatic reaction.

A tilt-table test was performed on 12 untrained subjects to evaluate the humoral adaptation to postural change. The observed peripheral reaction with a reversible short-term rise of norepinephrine (NE) and plasma renin activity (PRA) allowed us to divide the syndrome of the orthostatic dysregulation into a hyponoradrenergic and hypernoradrenergic type. This classification can be helpful for the clinical evaluation and therapy of orthostatic lability. The central excessive stimulation of the antidiuretic (ADH) and adrenocorticotropic hormone (ACTH) follow-ing orthostatic symptoms such as weakness or dizziness was not completely reversible within the observation period of 30 min. The ADH and ACTH increase was not different between the hypo- and the hypernoradrenergic type of dysregulation but was the most sensitive indicator of orthostatic lability: 41% of all subjects showed a hypernoradrenergic orthostatic dysregulation with pronounced NE response and alpha 2-adrenoceptor down-regulation. By use of antiembolism stockings (AES) or dihydroergotamine (DHE) this rate decreased to 16%. This was associated with a significantly reduced NE and PRA response and a diminished alpha 2-adrenoceptor number.

Adrenocorticotropic Hormone↗
PubMed1988

Potential of in situ hybridization for early diagnosis of productive cytomegalovirus infection.

In situ hybridization with a probe specific for immediate-early genes was used for detection of cytomegalovirus (CMV) transcripts in peripheral blood mononuclear cells, and the potential use of this technique as a diagnostic tool was assessed. The results were compared with those obtained with conventional assay systems. In 8 of 18 continually observed patients who developed a productive CMV infection, a high number of hybridization-positive cells were observed 1 to 2 weeks before the conventional tests yielded positive results. Thus, quantitative evaluation of hybridization results provided an early and specific marker for beginning CMV infection or reactivation. In three cases, quantitative in situ hybridization assays provided the only laboratory marker indicating CMV infection or reactivation. It was also found that a probe specific for immediate-early genes was superior to a probe specific for late genes for diagnosis of productive infections.

Antibodies, Viral↗
PubMed1988

[Can the number of donor kidneys for children be increased by using the kidneys of dead newborn infants?].

The donor pool for kidney transplantation in small children may be extended by the use of kidneys from deceased newborns. From 1973 to 1983 at our institution 189 mature newborns died, of which were 105 from the clinical point of view and 82 from the pathological-anatomical sight suitable as organ donors. The most frequent causes of death were disorders of the heart and circulation (60) and of the respiratory system (46). It is pointed to the problem of the establishment of brain death in newborns.

Cadaver↗
PubMed1988

1,25-Dihydroxy-vitamin D in infant formulas.

A method is described for determining 1,25-dihydroxyvitamin D in infant formulas without using high pressure liquid chromatography to separate the vitamin D metabolites. After preparative chromatography with Silica Sep Pak and C18-Sep Pak cartridges the dihydroxylated vitamin D metabolite was quantified in a specific protein binding assay. The concentration of 1,25-dihydroxyvitamin D found was in a range between 2.5 and 11.3 pg/ml.

Calcitriol↗
PubMed1987

[HIV (HTLV III/LAV) serology: experiences based on more than 42,000 tests].

1,032 sera of diverse origin (AIDS risk groups, prostitutes, inpatients, blood donors) exhibiting a positive HIV (HTLV III/LAV) ELISA result (Organon and/or Abbott) were investigated with different HIV confirmation assays (Western blot, WB; immunofluorescence, IF; competitive enzyme immunoassay against cloned gp41- and p24-antigen). Sera were finally evaluated as positive if at least two confirmation assays turned out positive (IF and WB; IF and p24, gp41; WB and p24, gp41; IF and WB and p24, gp41). Test results were considered false if the respective finding (IF or WB or p24, gp41) differed from two other confirmatory assays. 1,001 out of 1,032 sera (97%) yielded corresponding results in IF and WB. The remaining 3% of the investigated sera showed false positive, false negative, non-interpretable IF results and non-interpretable WB findings. The present study demonstrates that a positive HIV test should be confirmed by at least two confirmatory tests, one of which should be the WB. Non-corresponding results in confirmatory tests necessitate a third test system.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Studies on the glycosylation of flavivirus E proteins and the role of carbohydrate in antigenic structure.

The glycosylation pattern of several flavivirus E proteins as well as the role of carbohydrate in biological functions and the antigenic structure of tick-borne encephalitis (TBE) virus were investigated by the use of specific endoglycosidases. Endoglycosidase F digestion revealed the presence of a single asparagine-linked oligosaccharide side chain in TBE virus (Western and Far Eastern subtype), Louping III virus, Murray Valley encephalitis virus, and Rocio virus. Consistent with published sequence data, the E protein of West Nile virus apparently is not glycosylated at all. Evidence derived from digestion experiments using endoglycosidase H indicates that the tick-borne viruses contain high-mannose type N-linked oligosaccharide side chains, whereas that of the mosquito-borne Murray Valley encephalitis virus and Rocio virus is endoglycosidase H resistant. Complete deglycosylation of TBE virus by endoglycosidase F did not impair infectivity and HA activity. Carbohydrate does not seem to play a major role in the antigenic structure of the TBE virus glycoprotein since the reactivity of the native virus and the deglycosylated virus was identical when analyzed with monoclonal as well as polyclonal immune sera.

Antigens, Viral↗
PubMed1987

Multicentre dose range study of a yeast-derived hepatitis B vaccine.

Healthy young adult volunteers, 778 in number, without HBV markers were randomly distributed into groups and administered different lots of a yeast-derived hepatitis B vaccine (YDV) at different dose levels or a commercial plasma-derived vaccine (PDV), according to a 0, 1, 2, 12-month vaccination schedule. The YDV proved to be safe and well tolerated, even when partly purified lots were given. Reactions were mild and transient, comparable to those observed after PDV. One month after three YDV doses, 0-7% of subjects overall had failed to seroconvert; all those evaluated one month after the booster dose had seroconverted. No significant difference was found between the two vaccine types as far as seroconversion rates were concerned. Geometric mean anti-HBs levels following three vaccine doses were higher in seroconverters of the PDV groups. However, a booster dose of YDV resulted in high anti-HBs levels in all groups varying from 11,474 to 51,404 IU l-1 (purified YDV lot), 4915 to 18,832 IU l-1 (partly purified YDV lots) and 11,008 to 15,805 IU l-1 (PDV lots). Of seroconverters to the purified lots of YDV 93% attained 1000 IU l-1 after the booster dose, thus ensuring protection for a number of years. Dose-response studies provided a basis for the selection of 20 micrograms of highly purified YDV as the standard dose.

Adult↗
PubMed1987

Evidence for antigenic stability of tick-borne encephalitis virus by the analysis of natural isolates.

Strains of tick-borne encephalitis (TBE) virus isolated from ticks in natural foci in Austria were compared to strains isolated from the same foci 14 years previously. Comparative peptide mapping of the envelope (E) glycoproteins as well as analysis of the antigenic structure of the E proteins by the use of 14 monoclonal antibodies defining different epitopes did not provide evidence for antigenic variation. The same also holds true for isolates from a probably newly established natural focus in Western Austria. These results confirm previous data by showing that under natural ecological conditions TBE virus is quite stable and does not undergo major antigenic changes.

Animals↗
PubMed1987

Characterization of a disulphide bridge-stabilized antigenic domain of tick-borne encephalitis virus structural glycoprotein.

Proteolytic digestion of purified whole tick-borne encephalitis virus or its isolated envelope glycoprotein (E) in the form of rosettes yields an Mr 9000 fragment that is resistant to further digestion and carries polyclonal and monoclonal antibody-defined antigenic determinants. In a denaturation/renaturation experiment it was demonstrated that the antigenic reactivity of this domain, which was lost upon reduction and carboxymethylation, could be regained if the reducing agent was dialysed out before carboxymethylation. By the use of [35S]cysteine-labelled E protein and amino acid analysis it was confirmed that the reacquisition of antigenic reactivity in the renaturation experiment was associated with the reformation of disulphide bridges, which apparently confer structural stability to this part of the molecule. By the experiments performed we have identified an independently folding antigenically active domain of the E protein that is stabilized by disulphide bridges and has a strong tendency for renaturation.

Animals↗
PubMed1987

Problems in detection of cytomegalovirus in urine samples by dot blot hybridization.

A hybridization assay for the detection of cytomegalovirus (CMV) in urine specimens was established. Two different DNA fragments were used as hybridization probes: the HindIII L fragment (11.7 kilobases) and the EcoRI J fragment (10.6 kilobases) of the human CMV strain AD169. These probes were used in an isolated and highly purified form and therefore did not cross hybridize with vector sequences. As shown by hybridization with DNA from CMV-infected and uninfected cells, the assay was highly CMV specific and sensitive (detection limit, 750 to 500 fg of CMV DNA). A total of 122 urine specimens were examined by DNA hybridization, virus isolation, and the detection of CMV-induced early nuclear protein. The results coincided in 91% of the samples. The application of DNA hybridization to urine samples, however, is not without problems, and some of the pitfalls and drawbacks are discussed.

Cytomegalovirus↗
PubMed1987

[Comparison of two ELISA kits for the demonstration of antibodies against LAV/HTLV-III].

Eight hundred sera from a non-risk group and thousand sera from people at risk for acquiring AIDS were tested for the presence of LAV/HTLV-III specific antibodies by ELISA test kits manufactured by Du Pont and Organon. Western Blot analysis was used as a confirmatory test. All Western Blot positive sera were also positive in the Du Pont ELISA which in addition revealed a very low rate of false positive results (0.44%). In the Organon ELISA negative results were obtained with one positive and one questionable positive serum, as determined by Western Blot. The possible problem of test sensitivity being too low has been taken into account by the manufacturer by changing the calculation of cut-off values.

Acquired Immunodeficiency Syndrome↗