[Proliferation and differentiation of human osteoblasts from the nasal septum in a new perfusion culture system]. / Vermehrung und Differenzierung humaner Nasenseptum-Osteoblasten. Ein neuartiges Perfusionskultursystem.

BACKGROUND: Today, perfusion culture systems are mainly used to investigate cellular physiology and to cultivate three-dimensional tissue complexes. As a rule, these systems are relatively expensive and do not enable continuous microscopic monitoring of the growing cells. Simple and inexpensive perfusion culture systems have not been available up to now. METHODS: A novel perfusion culture system was developed in which the modular components consist of a mounting apparatus for inserting various media supply systems, microdispenser pumps, and laminar-flow culture chambers, each with a culture volume of 8 cm(3). The perfusion chambers were inoculated with human osteoblast cells from the tissue culture (5,000/cm(2)) and were perfused for 10 days after adherence of the cells (0.5 ml/min). As a control group, osteoblast-like cells were cultured in identically constructed culture chambers without medium perfusion. After 10 days, the cell counts were determined in accordance with the Coulter principle. Alkaline phosphatase was measured photometrically as a characteristic for differentiation. RESULTS: Compared with the control group, three to four times the quantity of cells were produced within 10 days in the perfusion cultures. The alkaline phosphatase values were equally high or only slightly lower, indicating that osteoblast differentiation of the cells was maintained with a higher proliferation. CONCLUSIONS: As large a number of in vitro proliferated cells as possible is a prerequisite for clinical application of tissue engineering. By continuously supplying medium, the tested perfusion culture system enables a higher rate of proliferation of osteoblast-like cells with maintenance of differentiation. Continuous microscopic monitoring of the cultures is possible using commercially available Petri dishes.

[Distribution of Borna disease virus in naturally infected animals with clinical disease]. / Die Verteilung des Bornavirus in natürlich infizierten Tieren mit klinischer Erkrankung.

Borna disease (BD) is a naturally occurring enzootic encephalomyelitis of horses and sheep. The aetiological agent, Borna disease virus (BDV) is an unclassified, neurotropic, negative stranded RNA virus. The study aimed at providing further information on BD of naturally infected animals. Samples obtained from 20 animals (18 horses, 1 donkey, 1 sheep) were investigated by a series of virological and molecular biological tests. The highly sensitive reverse transcription-polymerase chain reaction (RT-PCR) method was used to analyze the tissue distribution of BDV-specific RNA. BDV-specific RNA was detected in bulbus olfactorius, nucleus caudatus, hippocampus and cerebral cortex of all infected animals. BDV-RNA was also present in the spinal cord, eye, nasal mucosa, parotide gland, lung, heart, liver, kidney, bladder and ovaries. In addition, BV-specific RNA was also detected in conjunctival fluid, nasal secretions and saliva of two infected animals. By Western Blot assays the highest amounts of BDV antigens were demonstrated in bulbus olfactorius, nucleus caudatus, hippocampus and cerebral cortex.

Sequence analyses of the p24 gene of Borna disease virus in naturally infected horse, donkey and sheep.

By reverse transcriptase/PCR amplification and subsequent sequence determination of the p24 gene, the relatedness of Borna disease virus (BDV) in various naturally infected animal species was determined. These results are indicative of a common ancestral virus pool and a remarkably low species barrier of BDV. Comparison of 11 sequences to that of tissue culture adapted virus revealed that the homology among all isolates was at least 96.2% at the nucleotide level, and 97% at the amino acid level. Viral sequences from sheep, donkey and horse were found to be not more distantly related to each other than sequences from different infected horses. Tissue-specific virus variants were detected in one horse: the sequences established from infected cerebrum and kidney showed 10 mutations, whereas sequences obtained from parotid gland contained 20 mutations in comparison to the nucleotide sequence of MDCK cell adapted BDV.

[Preliminary results of the determination of plasmid profiles of veterinary Salmonella isolates]. / Erste Ergebnisse der Bestimmung von Plasmidprofilen veterinär-medizinischer Salmonella-Isolate.

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.

[Virulence factors of animal pathogenic Salmonellae with reference to plasmid typing]. / Virulenzfaktoren tierpathogener Salmonellen unter Berücksichtigung der Plasmidtypisierung.

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.