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Biomedical subjects

R Ahl

Publications and source records attributed to R Ahl.

At least 19 recordsLinked to original sources
PubMed2004

Increased left ventricular mass in obese adolescents.

AIMS: An increase of left ventricular mass (LVM) has been reported in obese adolescents in previous studies using echocardiography. The aim of our study was to determine the extent of the increase in LVM and correlation to other risk factors using cardiac magnetic resonance imaging in obese and lean adolescents. METHODS AND RESULTS: Nineteen obese and 20 lean adolescents were recruited. Following resting blood pressure measurements and blood sampling for insulin, triglycerides, and cholesterol levels, all subjects underwent cardiac magnetic resonance examination to assess LVM. LVM adjusted for body height was 16% greater in obese compared to lean adolescents (median 66 g/m, p = 0.0042). Obese subjects had higher resting systolic blood pressures than controls (median 115 vs. 110 mmHg, p = 0.0077) and higher fasting triglyceride and insulin levels. HDL-cholesterol levels were lower in the obese group compared with the lean group. CONCLUSIONS: Obese adolescents had a higher LVM than age-matched lean subjects, which correlated mainly with body mass index and systolic blood pressure. These findings add to the established cardiovascular risk profile of obese adolescents.

Adolescent↗
PubMed1998

[Classical swine fever].

The principles of aetiology, pathogenesis, diagnosis and immunology of classical swine fever as well as control measures are described. This review focuses on new diagnostic methods, immune reactions and possibilities for control of CSF in the context of the current eradication plans.

Animals↗
PubMed1997

[Quality management in the serodiagnosis of European swine fever: results of comparative tests].

In the course of inter-laboratory quality management comparative serological tests on classical swine fever (CSF) are conducted once per year. Results from tests carried out in 1994 and 1995 indicate that most regional diagnostic laboratories were able to classify the test sera correctly as CSF-positive, bovine viral diarrhea (BVD)-positive and negative, respectively. Difficulties were encountered in the differential diagnosis of CSF and BVD in neutralisation tests. There is a need to improve the standardization of CSF serology on the basis of a well established method in order to ensure reliability of test results and to enable comparison of results obtained from different laboratories.

Animals↗
PubMed1997

[Comparison of different BVD virus strains for their use in the differential diagnosis of classical swine fever--an attempt to standardize neutralization tests].

Six bovine virus diarrhoea (BVD) virus strains were tested in the neutralization test for their use in the differential diagnosis in classical swine fever (CSF) serology. The aim of the investigation was to find a suitable BVD virus strain guaranteeing a safe differentiation of CSF- and BVD virus induced antibodies using permanent cell cultures (PK-15, MDBK). For test purposes the neutralizing antibody titres of 73 defined test sera were titrated against the CSF virus strain Alfort/187 as well as the BVD virus strains Grub, Paplitz, NADL, 1138/69, Stendal, 10421/Han 94). Tests were repeated fivefold. The level of mean antibody titres, the differences in titre to the homologous pestivirus strain, the standard deviation and the variation coefficient served as test criteria. The BVD virus strains Grub and NADL yielded the best results. In view of harmonization and standardization the BVD virus strain NADL in connection with a standard protocol for neutralization tests is recommended for the differential diagnosis in CSF serology. Due to the adaptation of the permanent cell-lines PK-15 and MDBK to horse serum a further source of contamination with non cytopathogenic BVD viruses under routine conditions can be excluded.

Animals↗
PubMed1995

Detection of foot-and-mouth disease virus in nasal swabs of asymptomatic cattle by RT-PCR within 24 hours.

A method for extracting RNA from animal-derived materials that provides foot-and-mouth disease viral template suitable for Tth polymerase-dependent synthesis of cDNA and subsequent PCR is described. Viral genomes were detected in less than 24 h. Nasal swabs that can be easily and repeatedly collected, proved suitable for virus detection by PCR, even during the asymptomatic stages of infection.

Animals↗
PubMed1995

Differentiation of classical swine fever virus (CSFV) strains using monoclonal antibodies against structural glycoproteins.

Two panels of monoclonal antibodies (mAbs) against the classical swine fever virus (CSFV) envelope glycoproteins E2 (12 mAbs) and E0 (11 mAbs) were established and tested by immunoperoxidase binding assay against 135 pestivirus strains and isolates. Variability of the binding pattern was demonstrated for CSFV and also for bovine viral diarrhea virus (BVDV) strains and isolates. The panels of mAbs against E2 and E0 led to very different reactivity patterns. Particular mAbs against E2 reacted with (i) all CSFV isolates, (ii) only 4 out of 126 CSFV isolates, or (iii) about 90% of the tested CSFV isolates and 78% of ruminant pestivirus isolates. Anti CSFV E0 mAbs allowed the detection of a greater variability among the CSFV strains and isolates than the anti E2 mAbs. None of the 11 anti E0 mAbs recognized an epitope conserved for CSFV or showed crossreactivity with ruminant pestiviruses. The use of both panels of mAbs against two CSFV structural glycoproteins led to the discrimination of 21 antigenic types of CSFV strains and isolates. The described panels can be used to trace the origin of CSFV after outbreaks of the disease.

Animals↗
PubMed1995

Inactivation of viruses in liquid manure.

The stability of some viruses and methods of virus inactivation in liquid manure are reviewed. The authors discuss experimental data on the stability of foot and mouth disease virus, classical swine fever virus, Aujeszky's disease virus, African swine fever virus, swine influenza virus, porcine paramyxovirus, bovine virus diarrhoea virus and transmissible gastroenteritis of pigs virus. Recommendations and practical advice are given for the choice and application of chemical disinfectants for slurry.

Animals↗
PubMed1993

Amino acid changes outside the G-H loop of capsid protein VP1 of type O foot-and-mouth disease virus confer resistance to neutralization by antipeptide G-H serum.

Antiserum to a peptide corresponding to the 135-154 sequence of capsid protein VP1 of the foot-and-mouth disease virus O1 Kaufbeuren was raised in a pig. Although this serum contained neutralizing antibodies, the pig showed clinical symptoms after challenge. Virus isolated from this pig was identified as a mutant, with changes at positions 50, 198 and 211 of VP1 and at position 209 of VP2. This mutant, as well as a plaque isolate of it, differing from the challenge virus at positions 198 on VP1 (alanine being substituted for glutamic acid) and 209 on VP2 (histidine being substituted for tyrosine) resisted neutralization by the anti-peptide serum also in vitro. The same was observed with the O1 Kaufbeuren-related strain O1 Burgwedel, isolated from cattle in the field. It had substitutions only at positions 43 and 101 on VP1. The results show that neutralization epitopes flanking positions 145-147 on VP1 are modulated by other capsid protein parts. These parts seem to be important for neutralization escape in natural FMDV host species.

Amino Acid Sequence↗
PubMed1992

A second envelope glycoprotein mediates neutralization of a pestivirus, hog cholera virus.

Several monoclonal antibodies (MAbs) raised against hog cholera virus (HCV) reacted with the HCV structural glycoprotein gp44/48 and neutralized the virus. The presence of HCV gp44/48 on the viral surface was directly demonstrated by immunogold electron microscopy. Eight anti-HCV gp44/48 MAbs were tested by immunoperoxidase assay against a panel of pestivirus strains. Each MAb showed a distinct pattern of reactivity with HCV strains. It is suggested that the MAbs are well suited for epidemiological investigations of HCV outbreaks.

Animals↗
PubMed1990

Identification of foot-and-mouth disease virus replication in vaccinated cattle by antibodies to non-structural virus proteins.

Antibodies raised in cattle against foot-and-mouth disease virus by vaccination or by experimental infection were distinguished. Vaccination elicited only antibodies to virus capsid proteins and the polymerase 3D. Virus replication in cattle elicited additional antibodies directed against the non-structural proteins 2B, 2C, 3AB1, and/or 3C irrespective of prior vaccination or whether the cattle exhibited symptoms of disease. Non-permissive mice inoculated with virus responded in the same way, indicating that antibodies raised due to the transient presence of antigen are safely recognized by the method applied which was radioimmunoprecipitation. All kinds of infections were thus detected and it was possible to differentiate between cattle exposed or not exposed to challenge in the field, and further between protected animals and possible virus carriers.

Animals↗
PubMed1981

Effect of inhibitors of methylation on early and late interferon synthesis in bovine kidney cell cultures.

In virus infected bovine kidney cell cultures mainly late interferon is produced starting at about 4 hr after infection. Poly rI:poly rC induced cells as well as interferon pretreated virus infected cells produce early interferon starting immediately after induction. In infected cells the proportion of early interferon increases with time of interferon pretreatment, while late interferon is decreasing. Production of late interferon is selectively inhibited by cycloleucine, an inhibitor of S-adenosylmethionine (SAM) biosynthesis, whereas early interferon synthesis is not affected by the drug. Likewise, late interferon production is reduced much stronger than early interferon production by a combination of adenosine, L-homocysteine thiolactone, and erythro-9[3-(2-hydroxynonyl)]-adenine (EHNA) inducing in cells an accumulation of S-adenosylhomocysteine which inhibits SAM mediated methylation reactions. Inhibition of late interferon synthesis by cycloleucine is time and dose dependent and partially reversible. Cycloheximide equally blocks both early and late interferon production. Inhibition of incorporation of methyl groups into cellular RNA by the methylation inhibitors used is demonstrated by labeling with [methyl-3H] methionine and 3H-uridine. The results indicate that the synthesis of functional mRNA for early and late interferon is differentially sensitive to inhibition of methylation. The data suggest that, if early and late interferon is coded by the same structural gene, two different pathways are available for the cell to synthesize one species of mRNA.

Adenine↗
PubMed1980

Multiplication and distribution of Aujeszky's disease (pseudorabies) virus in vaccinated and non-vaccinated pigs after intranasal infection.

The primary sites of Aujeszky's disease virus (ADV) multiplication in intranasally (i.n.) infected pigs were found to be in the nasopharyngeal, tracheal and pulmonary regions. From the second day post infection (DPI) onward ADV invaded the central nervous system and other organs. The virus was isolated from the nasopharyngeal region for at least 2 weeks. In serum ADV was present with low levels from DPI 1 to DPI 7. In pigs vaccinated with an inactivated vaccine and then challenged the distribution of ADV was rather similar to that in non-vaccinated animals, in spite of the presence of neutralizing antibodies. The virus titres in the organs generally were lower than in non-vaccinated animals up to DPI 7. Thereafter, titre differences were no longer significant. Virus was isolated from the tonsils and the lungs for at least 2 weeks. Interferon production in vaccinated infected pigs was significantly lower than in non-vaccinated infected pigs. Though multiplication and dissemination of ADV occurred, vaccinated pigs did not show clinical symptoms of Aujeszky's disease. Traces of ADV were detected in a small percentage of white blood cells (WBC) of non-vaccinated infected pigs. ADV was isolated from the lymphocyte-enriched and polymorphnuclear leukocyte-enriched fractions, but not from the monocyte-enriched fractions, apparently on account of the small cell number. Multiplication of ADV was demonstrated in cultured WBC from some of the vaccinated and non-vaccinated infected animals.

Animals↗