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H Liebermann

Publications and source records attributed to H Liebermann.

At least 19 recordsLinked to original sources
PubMed1992

Some physicochemical properties of the virus of rabbit haemorrhagic disease.

Purified and concentrated preparations of virus from liver extracts of infected rabbits contain virus specific components with sedimentation coefficients of about 175, 110 and sometimes 133S and more slow units. Full and empty virus particles with a diameter of about 34 nm were shown electron microscopically in the corresponding 175 and 110S fractions of the sucrose density gradient. The average of buoyant density of the 175, 133, 110S and more slow units are 1.36, 1.32 and 1.31 g/ml respectively. The extinction coefficient E260 nm is 4.3 +/- 0.7 cm2/mg. The RNA content is 17 +/- 4%. SDS-PAGE shows a "65" kD protein as a single or major component. Beside smaller polypeptides with lower intensities, the 67 kD polypeptide reacts positively in the Western blot with polyclonal antibodies of rabbits. The molecular weight of the virus is 15 +/- 4 x 10(6)D. The pH stability of the 175S unit was also tested.

Animals↗
PubMed1992

Studies concerning etiology of sheep-associated malignant catarrhal fever in Europe.

The etiological agent of sheep-associated malignant catarrhal fever (MCF) in Europe has not been isolated directly from sheep. The occurrence of antibodies against the African bovine herpesvirus (BHV-3, WC 11) in cattle and sheep was examined using recently modified indirect immunofluorescence test (IIFT) and neutralization test (NT) methods. Studies revealed that sheep and cattle sera in Europe were free from neutralizing antibodies of BHV-3. The IIFT could not establish the presence of antibodies to African BHV-3 in cattle but revealed that about 22.4% of sheep sera reacted to it. Apart from the well known ovine herpesvirus (BHV-5), occurrence of another herpesvirus in Europe had been expected. This virus is not identical with the WC 11 strain, but it is in antigenic relationship to it. We had for the first time substantial serological evidence to the effect that sheep-associated MCF in Europe is a herpesvirus related to the African strain.

Animals↗
PubMed1991

RGD-containing peptides of VP1 of foot-and-mouth disease virus (FMDV) prevent virus infection in vitro.

RGD-containing peptides from the immunodominant region of VP1 between amino acids 135-160 from foot-and-mouth disease virus (FMDV) type O1 Kaufbeuren (O1K) prevented virus adsorption to piglet kidney (PK) cells. The highly conserved amino acid RGD sequence (Arg.-Gly.-Asp.) was a prerequisite of this effect. To prevent infection with 100-200 TCID50 in 10(6) PK cells, 20-250 micrograms of each peptide should have been added.

Adsorption↗
PubMed1991

[Hemorrhagic septicemia of rabbits (rabbit hemorrhagic disease, RHD)--quantitative antigen detection].

The efficiency of a vaccine of inactivated virus is influenced to a great deal by the mass of antigen per dose of application. Therefore it is essential to known the concentration of the antigen. We tested a physical method for quantification of the RHD-Virus. It implies a centrifugation of the prepurified, if necessary, preconcentrated infectious or inactivated virus in a gentle sucrose gradient. It is followed by analysis in a sensitive UV flow-through photometer with a computer calculated virus mass. The extinction coefficient (optical density) of the virus (175S-component) at 254 nm is 3.9 cm2/mg. The haemagglutination test and the ELISA were used to prove the virus specificity of the optical peak and partial for comparing them with the method mentioned above.

Animals↗
PubMed1991

[The occurrence and the importance of enterotoxins from strains of Escherichia coli from bovine mastitis].

Baby mouse and Y1 cell culturing tests were conducted into 117 Escherichia (E.) coli strains from mastitis of cattle to clear up enterotoxin formation. The rate of the latter was found to be relatively low, with enterotoxins recorded from only 7 strains (6%). No correlations were established between enterotoxin formation, on the one hand, and antibiotic resistance as well as biochemical activities of E. coli isolates, on the other. The question still remains open, if enterotoxin-forming strains derive their udder pathogenicity from endotoxins or with support by enterotoxins.

Adrenal Gland Neoplasms↗
PubMed1990

[Chemosynthetic peptides against foot-and-mouth disease--immune response to free and carrier bound peptides of the VP1 of O1-Kaufbeuren].

Three peptides of main epitope of FMD virus O1-Kaufbeuren, VP1 (16, 21, 31), were found to induce in the 130-160 sequence range, in free and/or carrier-bonded form, virus-neutralising antibodies in guinea pig, rabbit, mouse, swine, and cattle. Five carrier proteins were tested, with thyroglobulin, next to keyhole limpet hemocyanin (KLH), being most effective for 16-peptides (145-160) and 21-peptides (141-160 Tyr161). To protect guinea pig from FMD, minimum dosage of 21-peptide was found to be 2 x 8 micrograms. The immunogenic spectrum of peptides and conjugates proved to be broader than that of monovalent vaccines of inactivated virus. Free peptides were found to be also capable in vitro of inhibiting virus infection.

Animals↗
PubMed1990

Detection of T1-oligonucleotides of the foot-and-mouth disease virus RNA [correction of DNA] by silver staining.

Viral (v) RNA was isolated from purified foot-and-mouth disease virus (FMDV) by phenol-chloroform-isoamylalcohol treatment, digested by RNase T1 and separated by one-dimensional polyacrylamide gel electrophoresis (PAGE). The oligonucleotides were detected by silver staining. About 45 micrograms of vRNA corresponding to about 100 ml of infectious BHK-21 cell culture fluid yielded a pattern of nearly 20 bands sufficient to differentiate between the FMD viruses.

Animals↗
PubMed1990

Investigation of the influence of peptide-carrier conjugation on the immunological activity of VP1-peptides of foot-and-mouth disease virus O1-Kaufbeuren.

We found coupling of short sequences of VP1 to keyhole limpet hemocyanin (KLH) by means of glutaraldehyde to be a very complex phenomenon which could only be controlled by strict standardization of components and reaction conditions. Considering the results, we may conclude that big immunogenic proteins, like KLH, are advantageous for achieving sufficient and specific antibody response with neutralizing activity. When using KLH, we did not find simple dependence of immunogenicity or neutralizing activity on the incorporation rate of hapten in KLH in a region between 50 and 200. To develop a synthetic vaccine of good economy, investigations have to be continued, primary with a view to lowering the doses involved.

Animals↗
PubMed1990

Synthetic peptides against foot-and-mouth disease--immunization with VP1-peptides of type O1-Kaufbeuren.

Coupled synthetic peptides, representing the sequences of amino acids 130-160, 141-160 and 145-160 of foot-and-mouth disease virus O1K protein VP1, induced virus-binding and virus-neutralizing antibody response in guinea pigs, rabbits, and pigs. We also detected antibody response in guinea pigs after immunization with uncoupled peptides and in cattle with 21 aa-peptide-Keyhole-limpet hemocyanin (-KLH). The best results were obtained from 21 aa-peptide-KLH and 31 aa-peptide with or without KLH or thyroglobulin as carrier. Our preliminary results show the induction of virus-neutralizing antibodies to be obviously influenced by length of the peptide as well as by the kind of carrier and coupling.

Animals↗
PubMed1990

[Determination of virus concentration using a minicomputer].

Described in this paper is a physical method by which to determine virus concentrations, including ultracentrifugation of a sample through a saccharose gradient and subsequent analysis of tubule content by means of a flow photometer. Here before, the curves thus obtained used to be graphically evaluated by means of stencil plates. Direct recording and processing of the extinction-time curve by means of a KC 85/1 minicomputer have substantially improved accuracy of results. Time consumption has been reduced, and reading as well as calculating errors have been entirely ruled out. Repetition of determinations confirmed that virus concentrations could be determined at an accuracy of four to seven percent.

Animals↗
PubMed1990

Occurrence of caprine herpesvirus (BHV-6) infection in goat population of the GDR.

To clarify the occurrence of the caprine herpesvirus (BHV-6) infection in the goat population in the GDR, 175 sera, collected from the agricultural research station of Karl-Marx-Universität at Probstheida were tested for the presence of neutralizing antibodies against BHV-6. BHV-6 antibodies were present in 12% of the sera examined. The titer was low. Cross-neutralization of BHV-6 could not be determined with any other bovine herpesvirus. The goat sera tested were free of neutralizing antibodies against BHV-1 and BHV-3. The indirect immunofluorescence antibody test revealed cross-reactivity only between BHV-6 and BHV-1.

Animals↗
PubMed1990

[New types of virus infections of domestic animals in the German Democratic Republic. 3. Seroepizootiologic and experimental studies of herpesvirus infections in sheep--the etiology of pulmonary adenomatosis].

Neutralisation tests for antibodies against ovine herpesvirus were applied to 848 sera which had been sampled from different sheep herds across the GDR. Between six and 20 percent of sheep in the herds tested exhibited neutralising antibodies, notwithstanding their pulmonary adenomatosis status. Incidence and titre distribution of antibodies against ovine herpesviruses in pulmonary adenomatosis herds were identical with those recorded from unsuspected herds. From among 21 sheep with pathomorphologically secured pulmonary adenomatosis, six animals exhibited antibody titres just as high as those recorded from responders of all herds examined. Lambs were obtained by hysterectomy and raised without mothers and were experimentally infected with Herpesvirus ovis. All of these animals responded to infection by clearly rising titres (between 1:2 and 1:32). Adenomatous pulmonary lesions were not recordable from any of them. One lamb, following experimental ovine herpesvirus infection, exhibition, exhibited subclinical interstitial pneumonia. Herpesvirus ovis has been widespread in sheep herds across the GDR. The authors' serological and experimental investigations do not support the assumption of an aetiological relationship between ovine herpesvirus infection and incidence of pulmonary adenomatosis.

Animals↗
PubMed1990

[New types of virus infections of domestic animals in the German Democratic Republic. 4. Tahyna virus infections--a review].

A general account is given in this paper of history, incidence, pathogen properties, morphogenesis, isolation, and culturing of Tahyna virus. Reference is also made to methods for detection, host spectrum, immunity, epizootiology, pathogenesis, and clinical symptoms in man and animals and also to aspects relating to pathological anatomy as well as to regular and differential diagnosis.

Animals↗
PubMed1990

[Preliminary results of the determination of plasmid profiles of veterinary Salmonella isolates].

A plasmid of 60 Md magnitude was recorded from 40 in 41 Salmonella (S.) typhimurium strains, including the Copenhagen minus variant. A plasmid of that kind had been described in the international literature as serovar-specific of S. typhimurium. One S. typhimurium strain was without plasmid. Five contained the 60-Md and other plasmids. No relationship was found to exist between the 60-Md plasmid and biovar as well as chemotherapeutic resistance. Further studies will be necessary for consistent information on virulence association of this plasmid and its serovar specificity. Plasmid profiles were also checked in four S. enteritidis strain and additional serovars.

Animals↗
PubMed1990

[New types of virus infections of domestic animals in the German Democratic Republic. 1. Serologic survey studies of the distribution of equine torovirus infections in the GDR].

Sera collected from 124 horses were checked by means of the serum neutralisation test against equine Bern virus. Torovirusspecific antibodies were recordable from 35 percent of all horses tested. These results are likely to suggest that toroviruses are widespread in the GDR and occur not only in horses but in other domestic animals and in man, as well.

Animals↗
PubMed1989

[Virulence factors of animal pathogenic Salmonellae with reference to plasmid typing].

All the representatives of the genus Salmonella belong to one pathogenic species S. enterica. The virulence intensification of Salmonella are due mainly to endo-, entero- and cytotoxins, fimbria, cilia, the invasion capacity and the serum resistance. The plasmid code is among a series of virulence factors. Studies about the plasmid profile of the salmonella strains is of great importance to the characterisation of the isolates from the epidemiological point of view as well as for research purposes.

Animals↗