Biomedical subjects

P Timms

Publications and source records attributed to P Timms.

81 records · Page 5Linked to original sources

PubMed1982

A microplate enzyme immunoassay for detecting and measuring antibodies to Babesia bovis in cattle serum.

A microplate enzyme immunoassay (EIA) is described for measuring IgG antibody to Babesia bovis in cattle serum. B. Bovis antibody status (whether positive or negative) and the amount of B. Bovis antibody (EIA score), were measured by comparison with reference serums. The EIA was shown to be specific for B. Bovis, and EIA score correlated well with EIA titre. Comparison of EIA with the Indirect Fluorescent Antibody Test (IFAT) showed more than 95% agreement between the methods and disagreement in only 1.6% of serum samples tested. The remaining 3.2% were positive by EIA and suspected positive by IFAT. The EIA was shown, by titrating positive serums, to be more sensitive than IFAT, which explained its tendency to detect more positive serums than IFAT. EIA detected B. bovis antibody in experimentally infected cattle by day 14 post infection (pi) and for at least 268 days pi. EIA score for B. bovis antibody in immune cattle increased significantly (p less than 0.05) following heterologous strain challenge.

Animals↗

PubMed1982

Preparation and laboratory testing of a frozen vaccine containing Babesia bovis, Babesia bigemina and Anaplasma centrale.

Procedures used to prepare and test frozen vaccine against bovine tick fever are described. Blood from splenectomised calves infected separately with Babesia bovis, Babesia bigemina and Anaplasma centrale was diluted in the ratio of 3:1 with 8 M dimethyl sulphoxide in phosphate buffered saline and cooled at rates between 5 degrees C and 110 degrees C per minute to -196 degrees C. After varying periods of storage up to 369 days, blood was thawed by immersing containers in a 40 degrees C water bath and its infectivity tested in a total of 150 nonsplenectomised cattle. Subcutaneous inoculation of the cryopreserved blood, and 10-fold and 50-fold dilutions prepared from it, showed that high infectivity of all three parasites was retained during storage. The use of frozen vaccine exported from Australia to Trinidad and Tobago is briefly discussed.

Anaplasma↗

PubMed1982

Variable and common antigens of Babesia bovis parasites differing in strain and virulence.

Virulent and avirulent K strain (KV and KA) and virulent L strain (LV) Babesia bovis parasites were biosynthetically labeled with 35S-methionine. Labeled proteins, extracted in detergent from infected cultures, were analyzed by two-dimensional gel electrophoresis. Protein antigens common to these forms of babesia and those specific for strain and correlating with the degree of virulence were identified by immunoprecipitation with antisera. Dominant labeled protein antigens were found to differ both between the K and L strains of B. bovis and between virulent (KV) and avirulent (KA) forms of the K strain. Partial cleavage of biosynthetically labeled proteins by staphylococcal V-8 protease and peptide mapping revealed that no extensive amino acid homology existed between the candidate variant antigens. KA B. bovis parasites are currently in use as a live attenuated vaccine for bovine babesiosis in Australia. Antigens that are better expressed in KA relative to virulent strains may therefore be markers of avirulence and/or candidate "host-protective antigens" of B. bovis. At least one protein (Mr 43,000) was identified as being a dominant labeled antigen of KA that is poorly represented in the KV and LV B. bovis isolates.

Antigens↗

PubMed1981

Inhibition of Babesia spp. by plastics.

Five commercially available plastic containers were compared with glass for toxicity toward Babesia rodhaini and Babesia bigemina. Comparisons were made by using infectivity tests in mice (B. rodhaini) and cattle (B. bigemina). Low-density polypropylene and polystyrene containers were not toxic, but two of the three polyvinyl chloride containers tested significantly reduced the viability of both species of Babesia. Plasticizer present in various amounts on the surface of the toxic containers was most likely the inhibitory material.

Animals↗

PubMed1980

Collection and sterilization of large volumes of bovine serum and its use in vaccines against bovine babesiosis and anaplasmosis.

A method is described for the collection and sterilization of 100 1 batches of bovine serum. Serum was prepared by defibrination of 20 1 volumes of whole blood using an impeller spinning at 400-500 rev./min. After freezing and thawing the raw serum was clarified through milk filters, pre-filtered through cartridge filters and sterilized by membrane filtration. The bacteriologically sterile serum was used in vaccines against bovine babesiosis and anasplasmosis after testing indicated no toxicity for Babesia and Anaplasma.

Anaplasma↗

PubMed1980

Erythrocytic Na+ and K+ changes during Babesia bigemina infection in cattle.

The levels of Na+ and K+ in whole blood, plasma and erythrocytes were measured during the course of primary Babesia bigemina infection in cattle. There were significant changes in the levels of Na+ and K+ in erythrocytes, but not in plasma. Erythrocytic Na+ decreased and K+ increased during the course of infection, returning to normal two to three weeks later. Similar ionic changes were produced in animals which were bled to cause packed cell volume depression. It is therefore suggested that the changes in erythrocytic Na+ and K+ levels associated with B bigemina infection result from the anaemia rather than simply the presence of the parasites, and can be attributed to the production of young erythrocytes in which the levels of Na+ and K+ are normally reduced and elevated, respectively. Normal values return with recovery from anaemia and maturation of erythrocytes.

Animals↗

PubMed1980

Short term cultivation of Babesia species.

A method based on the candle jar technique was used for the cultivation of Babesia bovis, B bigemina and B rodhaini in vitro. All three parasites multiplied within their host red blood cells and were well maintained for up to 96 h in culture. Regular changes of medium and subculture at 24 h were essential for optimal parasite survival. A 40 per cent suspension of red blood cells was found to give better results than the 10 to 12 per cent suggested by Jensen and Trager for the cultivation of Plasmodium falciparum.

Animals↗

PubMed1978

Thryo-endocrine pathology, obstetric morbidity and schizophrenia: survey of a hundred families with a schizophrenic proband.

This preliminary communication reports that the mothers of 104 schizophrenic patients had: (1) a significantly higher incidence of thyroid disease than a carefully matched control group; (2) significantly more abortions, still-births and greater infant mortality. The findings and possible relevance of thyroid disease to schizophrenia are discussed. Three prospective studies currently in progress are outlined.

Abortion, Spontaneous↗

PubMedDate not supplied

Analysis of promoter sequences from Lactobacillus and Lactococcus and their activity in several Lactobacillus species.

Promoter-active fragments were isolated from the genome of the probiotic organism Lactobacillus rhamnosus strain GG using the promoter-probe vector pNZ272. These promoter elements, together with a promoter fragment isolated from the vaginal strain Lactobacillus fermentum BR11 and two previously defined promoters (Lactococcus lactis and Lactobacillus acidophilus ATCC 4356 slpA), were introduced into three strains of Lactobacillus. Primer-extension analysis was used to map the transcriptional start site for each promoter. All promoter fragments tested were functional in each of the three lactobacilli and a purine residue was used to initiate transcription in most cases. The promoter elements encompassed a 52- to 1,140-fold range in promoter activity depending on the host strain. Lactobacillus promoters were further examined by surveying previously mapped sequences for conserved base positions. The Lactobacillus hexamer regions (-35: TTgaca and -10: TAtAAT) closely resembled those of Escherichia coli and Bacillus subtilis, with the highest degree of agreement at the -10 hexamer. The TG dinucleotide upstream of the -10 hexamer was conserved in 26% of Lactobacillus promoters studied, but conservation rates differed between species. The region upstream of the -35 hexamer of Lactobacillus promoters showed conservation with the bacterial UP element.

Animals↗