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Biomedical subjects

G Enders

Publications and source records attributed to G Enders.

At least 109 records · Page 6Linked to original sources
PubMed1988

Passage of stone fragments from the gallbladders of dogs.

The destruction of gallstones by shock waves leads to a considerable amount of stone fragments in the gallbladder. To test the ability of the stones fragments to leave the gallbladder, kidney stone fragments of 2 or 4 millimeters maximal diameter were implanted into the gallbladders of 16 dogs and passage was observed for five weeks. Independent of stone size, about 35 per cent of the fragments remained in the gallbladder. Transient elevations of enzymes of the liver or pancreas occurred significantly less often with 2 millimeter fragments and were less pronounced. Gross pathologic changes of the papilla of Vater, or dilation of the bile duct were observed with 4 millimeter fragments but not with those that were 2 millimeters. The results of this study suggest that the maximal fragment size after destruction of gallstones should be as small as possible, that is, in the range of 2 millimeters.

Animals↗
PubMed1988

[Rubella vaccination: antibody persistence for 14-17 years and immune status of women without and with a history of vaccination].

Out of 1045 women who had been successfully vaccinated with Cendehill vaccine, 195 were tested for rubella antibodies 13-17 years later and still 98% were seropositive with a geometric mean titer (GMT) of 2-5.4 (1:42). In 7.8% and 21.6% only borderline or low hemagglutination inhibition (HAl) titer were found. A reinfection rate of 12.2% was determined by significant titer rises and IgM antibody detection in 466 vaccinees with 3 or more blood samples during the observation period. Out of 312 successfully vaccinated girls aged 11-16 years with HPV77DE5 and RA 27/3, 130 could be retested 14 years later and all were found seropositive with a GMT of 2-5.8. Low HAl titers of 1:16 have been found in 6.2% (8 cases). The rubella immune status of 11,0978 postpubertal and pregnant women in South-West Germany was determined between 1981 and 1987. 9824 of these women had a history of vaccination and only 2.4% were seronegative in contrast to 8.2% of 101,154 women with no history of vaccination. There was a significantly higher prevalence of low levels (HAl 1:8, 1:16) of antibodies among women with a history of vaccination (19.4%) than among those without (10.6%, p less than 0.001). The effect of reinfection in pregnancy following previous vaccination on the newborn is discussed.

Antibodies, Viral↗
PubMed1987

Biological effects of shock waves: lung hemorrhage by shock waves in dogs--pressure dependence.

The most serious side effect observed during the destruction of gallstones by shock waves in dogs was lung bleeding. To determine the conditions leading to lung damage, pressure probes were implanted into dogs between the lung and the diaphragm. The distance between the lung and the focal point of the pressure field was determined at which 1000 shock waves caused no more lung hemorrhage. On the long axis it is greater than 15 cm and perpendicular to the long axis it is 4 cm. Shock wave pressures over 2 MPa could be administered safely, whereas a pressure of 10 MPa caused bleedings in beagles, but probably not in boxers.

Animals↗
PubMed1987

Expression of the precore region of an avian hepatitis B virus is not required for viral replication.

The core-antigen-coding region of all hepadnaviruses is preceded by a short, in-phase open reading frame termed precore whose expression can give rise to core-antigen-related polypeptides. To explore the functional significance of precore expression in vivo, we introduced a frameshift mutation into this region of the duck hepatitis B virus (DHBV) genome and examined the phenotype of this mutant DNA by intrahepatic inoculation into newborn ducklings. Animals receiving mutant DNA developed DHBV infection, as judged by the presence in hepatocytes of characteristic viral replicative intermediates; molecular cloning and DNA sequencing confirmed that the original mutation was present in the progeny genomes. Infection could be efficiently transmitted to susceptible ducklings by percutaneous inoculation with serum from mutant-infected animals, indicating that infectious progeny virus was generated. These findings indicate that expression of the precore region of DHBV is not essential for genomic replication, core particle morphogenesis, or intrahepatic viral spread.

Animals↗
PubMed1986

Synthesis of measles virus-specific IgM antibodies and IgM-class rheumatoid factor in relation to clinical onset of subacute sclerosing panencephalitis.

Thirty-seven serum and 37 cerebrospinal fluid (CSF) specimens from 27 patients with subacute sclerosing panencephalitis (SSPE) were tested for measles virus (MV) IgM antibodies and IgM-class rheumatoid factor (RF) to determine if a temporal relationship exists between SSPE onset and these immunoglobulins. Sensitive solid-phase radioimmunoassays were used for immunoglobulin detection. Five of six MV IgM-positive CSF, both MV IgM-positive sera and six out of eight sera with elevated RF levels were collected within 1 yr of SSPE onset. Also collected during this time were six other sera having high binding in the MV IgM assay, which was not due to MV-specific IgM antibodies. Two of these sera had as high or higher binding of IgM to a Vero cell control antigen, suggesting involvement of an IgM-class autoantibody. The other four sera had false-positive MV IgM assay results due to RF interference. RF interference was dependent on both the titer and avidity of the MV IgG antibodies involved. Three conclusions can be drawn from these results. First, MV IgM antibodies and elevated RF levels are not markers for acute SSPE, despite the tendency for their synthesis at this stage of the disease. Second, immunoassay analysis of viral IgM antibodies must employ an appropriate control antigen to account for background IgM binding. Finally, even if RF levels are normal or near normal, a false-positive IgM immunoassay result can still occur if antigen-specific IgG antibodies in the same sample have the right combination of titer and avidity.

Antibodies, Viral↗
PubMed1986

Detection of IgM antibodies against rubella virus: comparison of two indirect ELISAs and an anti-IgM capture immunoassay.

A commercial antibody capture enzyme immunoassay (Rubenz M) was compared to two commercial indirect enzyme immunoassays (Enzygnost IgM, Rubazyme-M) for the detection of rubella-specific IgM. Five hundred and fifty-two sera collected between the day of onset and 272 days after the onset of the exanthem of primary rubella were tested. Rubenz M was more sensitive early and late after the onset of the exanthem than the two indirect ELISAs. Rubenz M also appeared more sensitive when 240 sera were examined from patients with possible rubella in pregnancy, reinfection in pregnancy, suspected intrauterine infection, and recent vaccination. However, 5.5% of 968 pregnant women with no history of rubellalike symptoms or recent vaccination, the majority with elevated HAI titers, gave a low-positive or borderline result with Rubenz M. None of these women delivered a congenitally infected child. Therefore, borderline and low-positive results must be interpreted with caution, as for any assay for rubella-specific IgM.

Antibodies, Viral↗
PubMed1986

Induction of oral tolerance in rats without Peyer's patches.

The induction of oral tolerance after ingestion of antigen has been reported in several animal models. The precise mechanisms responsible for this unresponsiveness are not well understood. As some investigations have suggested a key role of Peyer's patches suppressor T cells, an animal model was developed in which the PP were surgically removed. Using this model, the influence of the PP on the induction of oral tolerance against SRBC was investigated. In order to induce tolerance, the rats were fed SRBC on four consecutive days. On Day 5 they were i.p. challenged by injection of SRBC, and 5 days later the number of immunoglobulin-secreting cells against SRBC was determined within the spleen. Using this protocol, the oral tolerance induction could be shown very clearly in control animals as well as in rats without PP. Therefore, tolerance induction is possible in the absence of PP-T cells. Other mechanisms must be responsible for the tolerance induction in this model.

Animals↗
PubMed1985

Comparison of various serological methods and diagnostic kits for the detection of acute, recent, and previous rubella infection, vaccination, and congenital infections.

The antibody development after natural rubella infection and rubella vaccination has been followed in 802 sera from 493 patients and 71 sera from 22 vaccinees. Also examined were 67 sera from 28 infants with rubella embryopathy and sera from 50 children with presumed prenatal infection. In addition, 777 sera from 641 patients tested for routine rubella diagnosis were studied. Anamnestic information was available from all these patients. These sera were assayed for IgM antibody detection by sucrose density gradient (SDG), the commercial ELISAs (Enzygnost IgM and Rubazyme M), and the non-commercial anti-my-hemadsorption immunosorbent technique (HIT). For the determination of IgG antibodies the hemagglutination inhibition test (HAI), the commercial ELISAs (Enzygnost IgG, Rubazyme), and a single radial hemolysis test (SRH) were used. The SDG and HIT were less sensitive for IgM antibody detection than the two ELISAs, particularly when IgM concentrations were low. In total 26.5% of the IgM results with the newer tests were discordant with SDG, but only 0.5-1.3% of these results were not explicable when the clinical data was considered. Problems were encountered with all IgM assay systems used. For the detection of rubella antibodies after acute infection and vaccination the ELISA Enzygnost IgG was as sensitive as the HAI whereas the ELISA Rubazyme and SRH detected antibodies with some delay. Corresponding results with all tests were found more than 25 days after acute infection and more than 50 days after vaccination. All methods can be used for detection of antibodies in infants with rubella embryopathy. The results of this study suggest that certain combinations of tests can be used for the reliable detection of rubella infection.

Adult↗
PubMed1985

Comparison of the performance and reproducibility of various serological methods and diagnostic kits for the detection of rubella antibodies.

For rubella antibody detection performance and reproducibility of standard laboratory methods and newer assay systems have been evaluated. IgM antibody detection in sucrose density gradient ultracentrifugation (SDG) was compared with two commercial ELISAs and the non-commercial anti-my-hemadsorption immunosorbent technique. The two ELISAs proved to be more sensitive than the SDG even if done with a long incubation hemagglutination inhibition test (HAI) to increase sensitivity. Additional tests showed that the sensitivity of the SDG could be increased by using ELISA instead of HAI. The reproducibility of all tests was good. In 205 assays the ELISA enzygnost IgM showed a coefficient of variation (CV) with its reference serum of 6.3% for titers, while the CV for absorbance was 37.8%. With ELISA rubazyme M the same reference serum gave a CV of 13.7% in 149 subsequent assays. In 12 and 13 assays in the anti-my-hemadsorption immunosorbent technique the CV varied with the height of the reference serum used between 4.7 and 18.7%. Antibody detection using HAI was compared with IgG antibody detection using two commercial ELISAs and a commercial single radial hemolysis test (SRH). In 592 assays with a low positive control serum the HAI gave a CV of 6.0%. With the ELISA enzygnost a CV of 7.7% for the titers was obtained in 72 assays, but for absorbances the CV was 39.4%. The CV for the kit internal low positive control in 148 assays with the ELISA rubazyme was 26.8%. As with HAI the reproducibility of the SRH was good. The same control serum used in the HAI gave a CV of 6.2% in 418 subsequent assays. Because of the good reproducibility and sensitivity the SDG can now be replaced by newer techniques which are less expensive and time consuming. Interference with rheumatoid factor was only observed in the ELISA enzygnost if sera were not pretreated with latex adsorbents. The reproducibility of our HAI was comparable to that of the SRH while the results obtained with the two commercial ELISAs were less reproducible. Until it is known, that antibodies detected with the newer techniques are able to prevent re-infection, it would be unwise to reject the HAI completely for the determination of immunity status.

Antibodies, Viral↗
PubMed1985

Management of varicella-zoster contact and infection in pregnancy using a standardized varicella-zoster ELISA test.

An ongoing 5-year prospective study of the outcome of contact with varicella-zoster virus (VZV) and infection in pregnant women has made use of a standardized VZV enzyme-linked immunosorbent assay for the determination of immune status and as a guide for therapeutic management. Out of of a total of 778 such cases investigated to date in the Federal Republic of Germany, 93.1% have been shown to be VZV immune, whereas 6.9% were seronegative and, therefore, susceptible to infection. Those of the latter group who received zoster hyperimmunoglobulin (ZIG) between 24-96 hours after varicella contact remained symptom-free, while women receiving ZIG from the 3rd-10th day after contact developed a modified varicella. For the prevention of varicella, ZIG with known titres should be administered at doses of 0.2-0.4 ml/kg. It is also recommended for the newborn when maternal infection occurs within 4 days before until 2-4 days after delivery. The prevention and attenuation of varicella in pregnancy is justified since the outcomes may include spontaneous abortion in early pregnancy, the congenital varicella syndrome, and severe neonatal disease with a rather high mortality around term.

Abortion, Spontaneous↗