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Biomedical subjects

P Olson

Publications and source records attributed to P Olson.

52 records · Page 3Linked to original sources
PubMed1987

Campylobacter in the dog: a clinical and experimental study.

Faecal samples from 54 dogs with diarrhoea and 54 control dogs were cultured for Campylobacter, Salmonella and Yersinia species and controlled for enteric viruses. The campylobacter were identified as either C jejuni/coli or C upsaliensis. In the diarrhoeic group 16 dogs (29.6 per cent) were positive for campylobacter, 10 C upsaliensis and six C jejuni/coli. Concomitant infection with parvovirus was evident in six of the dogs with diarrhoea and campylobacter-positive faecal cultures. In the control group 13 dogs (24.1 per cent) were positive for campylobacter; three of the isolates were C upsaliensis and six C jejuni/coli. Four isolates could not be identified. The most prominent clinical findings in naturally occurring cases were an acute onset of vomiting (12 of 16), diarrhoea (16 of 16) which was often haemorrhagic (nine of 16) and a raised rectal temperature. Dogs were infected experimentally with both C jejuni (three dogs) and C upsaliensis (three dogs). The challenge strains could be identified in faecal samples from all the dogs, but clinical signs of diarrhoea were seen in only one dog infected with C jejuni. Soft faeces was passed by one dog infected with C upsaliensis. It is concluded that C jejuni/coli or C upsaliensis are either primary pathogens or, after predisposing factors such as virus infections, act as secondary pathogens. It also seems probable that Campylobacter species are present in the intestinal flora of the normal dog.

Animals↗
PubMed1986

Transformations of arylpropane lignin model compounds by a lignin peroxidase of the white-rot fungus Phanerochaete chrysosporium.

Various lignin model compounds of the O-arylpropane type were oxidized with purified lignin peroxidase from the white-rot fungus Phanerochaete chrysosporium, and oxidation products were identified by gas-chromatography/mass-spectroscopy procedures. Our results are in accord with the theory that lignin peroxidase catalyzes one-electron oxidations of its substrates with formation of cation radicals, and that these radicals undergo degradative reactions that are predictable from a knowledge of cation radical and oxygen chemistry. Cation radicals formed from O-arylpropane model compounds appeared to undergo the following types of degradative transformations: addition of water to ring-centered radicals, followed by proton loss yielding quinones and alcohols; nucleophilic attack by hydroxy functions on propanoid moieties giving cyclic ketals as intermediates which decompose to yield side chain migration products; transfer of the charge of a radical from a ring to the associated alkyl moiety through an ether bond, with loss of a proton from the latter, forming a new carbon-centered radical. The new alkyl-centered radicals apparently were able to abduct dioxygen to form peroxyl radicals which decomposed giving a variety of oxidation products and probably superoxide anion. Specific examples of the above transformations are presented, and their relevance to lignin degradation is discussed.

Basidiomycota↗
PubMed1985

Enterotoxigenic Escherichia coli (ETEC) and Klebsiella pneumoniae isolated from dogs with diarrhoea.

Faecal samples from 148 dogs with diarrhoea and from 15 healthy dogs were cultured for bacterial pathogens with enterotoxigenic properties. The aim of the study was to define the toxin profile (production of heat-labile [LT] and heat-stable [ST] toxins) and possible surface fimbrial antigens. Enterotoxigenic bacteria were isolated from 6 (4.1%) dogs with diarrhoea, four of these were Escherichia coli and two were Klebsiella pneumoniae. The E. coli strains and K. pneumoniae strains were producing both LT and ST toxins. The LT toxin from these strains was not neutralized by human anti-LT serum or anti-choleragen and did not cause coagglutination with Staphylococcus aureus coated with anti-human-LT. This suggests that the LT toxin produced by these canine isolates is non-identical to LT toxin from human strains. Three of the ETEC strains were haemagglutinating and showed surface hydrophobic properties. Electron microscopy showed that canine ETEC isolates possessed fimbriae of two different types: thick (5-5.5 nm) and thin (2-3 nm).

Animals↗
PubMed1982

Evaluation of a killed feline panleukopenia virus vaccine against canine parvoviral enteritis in dogs.

Immunogenic potency of a killed feline panleukopenia virus vaccine against canine parvoviral enteritis in dogs was examined. The vaccine elicited hemagglutination-inhibition antibodies to canine parvovirus (CPV) in all of the 72 dogs which were vaccinated. The vaccine was protective in dogs against both experimentally induced and naturally occurring CPV-induced disease. By statistical analysis, 4 weeks was found to be the optimal spacing between 2 vaccinal doses resulting in hemagglutination-inhibition antibody titers up to 1:5,120. Adverse reactions to the vaccine were not observed. Atypical lymphocytes were found consistently in the CPV-infected control dogs.

Animals↗
PubMedDate not supplied

Breed risk of pyometra in insured dogs in Sweden.

An animal insurance database containing data on over 200,000 dogs was used to study the occurrence of pyometra with respect to breed and age during 1995 and 1996 in Swedish bitches <10 years of age. A total of 1,803 females in 1995 and 1,754 females in 1996 had claims submitted because of pyometra. Thirty breeds with at least 800 bitches insured each year were studied using univariate and multivariate methods. The crude 12-month risk of pyometra for females <10 years of age was 2.0% (95% confidence interval = 1.9-2.1%) in 1995 and 1.9% (1.8-2.0%) in 1996. The occurrence of pyometra differed with age, breed, and geographic location. The risk of developing pyometra was increased (identified using multivariate models) in rough Collies, Rottweilers, Cavalier King Charles Spaniels, Golden Retrievers, Bernese Mountain Dogs, and English Cocker Spaniels compared with baseline (all other breeds, including mixed breed dogs). Breeds with a low risk of developing the disease were Drevers, German Shepherd Dogs, Miniature Dachshunds, Dachshunds (normal size), and Swedish Hounds. Survival rates indicate that on average 23-24% of the bitches in the databases will have experienced pyometra by 10 years of age. In the studied breeds, this proportion ranged between 10 and 54%. Pyometra is a clinically relevant problem in intact bitches, and differences related to breed and age should be taken into account in studies of this disease.

Age Factors↗
PubMedDate not supplied

A model of eldercare in the People's Republic of China.

Rapid industrialization in the People's Republic of China (PRC) since the late 1970s offers a unique opportunity to explore the relation between the political economy and the social support systems for the growing proportion of the elderly. Four categories of aged are identified and assistance to the aged is provided through three support systems. Analysis reveals that the future of the elderly in the PRC will be greatly influenced by: the political agenda, the degree to which traditional values toward the aged are preserved, the degree to which the eldercare support system continues to be built on the existing social structure, the degree to which the eldercare program becomes institutionalized in the state budget, and the degree to which the elderly continue to be integrated into society.

Aged↗
PubMedDate not supplied

Highly efficient eukaryotic gene expression vectors for peptide secretion.

Recently, we constructed a series of highly efficient universal eukaryotic gene expression vectors (Sheay et al., BioTechniques 15:856-862, 1993). Such vectors contain a viral promoter and enhancer followed by the adenovirus tripartite leader sequence, a multiple cloning site for the insertion of the gene of interest and a polyadenylation sequence. To enable expression of peptides to be secreted into the tissue culture medium or to be incorporated into the cell membrane, several modifications have been introduced into such vectors: stop codons in all three reading frames were inserted at the end of the multiple cloning site and a DNA sequence coding for a signal peptide for transport through the endoplasmatic reticulum (ER) was introduced downstream of the adenovirus tripartite leader sequence followed by two unique restriction enzyme recognition sites. A protocol is described that allows fast and easy cloning of peptide-coding regions, i.e., PCR products, for expression and secretion. The transport of a genetically engineered chimeric transmembrane protein connected to this ER leader sequence was as efficient as that of the original protein from which the ER sequence has been derived. These universal vectors can also be used for the easy construction of any chimeric transmembrane or secretion proteins.

Amino Acid Sequence↗