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Biomedical subjects

K M Moriarty

Publications and source records attributed to K M Moriarty.

At least 19 recordsLinked to original sources

Mycobacterium paratuberculosis binds fibronectin.

Fibronectin, an adhesive glycoprotein which is present in plasma and on many host cell surfaces of many host organisms, binds to certain bacterial pathogens. This study demonstrates the ability of Mycobacterium paratuberculosis (M.ptb) to interact with 125I-labelled fibronectin purified from bovine and ovine plasma. Two M.ptb strains were tested: a clinical isolate and a commercially available vaccine strain. Both strains showed significant fibronectin-binding activities of 22 and 41%, respectively, whereas non-pathogenic M.phlei had almost no affinity for fibronectin. Binding activities were similar for ovine and bovine fibronectin. We found that fibronectin binding by M.ptb was (1) time-dependent, reaching saturation within 90 min, (2) specific, since it was inhibited by an excess of unlabelled fibronectin but not by albumin, (3) saturable, with an apparent dissociation constant of 1.25 x 10(-9) M and a maximal number of 1,600 binding sites per bacterium, and (4) sensitive to detergents, proteases and heat treatments, indicating the protein nature of the responsible binding component(s). Scatchard plot analysis gave a straight line suggesting the presence of a single type of fibronectin receptor on M.ptb.

Animals

Expression of Escherichia coli beta-galactosidase in Mycobacterium bovis BCG using an expression system isolated from Mycobacterium paratuberculosis which induced humoral and cellular immune responses.

A promoter sequence, PAN, was isolated from Mycobacterium paratuberculosis and characterized. This promoter lies adjacent to, and outside, the 3' end of an IS900 insertion element. IS900 contains an open reading frame, ORF2, on the complementary strand which codes for the putative transposase of this insertion sequence. A DNA fragment containing PAN and part of ORF2 was fused to the lacZ gene and inserted into the replicative shuttle vector pRR3. Mycobacterium smegmatis and Mycobacterium bovis BCG (BCG) transformed with this plasmid exhibited beta-galactosidase activity. However, lacZ was only expressed in Escherichia coli under the control of PAN, when ORF2 was deleted. Immunization of mice with the recombinant M. bovis BCG expressing lacZ resulted in the induction of a high humoral and cellular response directed against beta-galactosidase. The PAN-ORF2 expression system may prove to be particularly useful for cloning and expression of heterologous genes in the BCG vaccine strain.

Amino Acid Sequence

Protein antigens secreted by Mycobacterium paratuberculosis.

Proteins secreted by Mycobacterium paratuberculosis (M.ptb) during short-term cultivations were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western(Immuno) blotting. Cultivation in a defined medium containing 35S methionine allowed autoradiographic detection of proteins which had been secreted or passively released by actively metabolizing M.ptb organisms. After the first 3 days of cultivation, 4 proteins with molecular weights of approximately 38, 50, 65 and 110 kilodaltons (kd) were detected on SDS gels. Longer incubation up to 12 days resulted in an increased concentration of these proteins as well as in appearance of additional proteins ranging from 14 to over 90 kd. In long-term (8-10 weeks) culture filtrates only two prominent proteins with molecular weights of 30 and 65 kd proteins could be detected. Immunoblot analysis showed that some of the proteins secreted during short-term cultivations were recognized by sera from M.ptb-infected sheep and more significantly by sera from animals which had been immunized with a M.ptb live vaccine strain. The study indicates that during short incubation times M.ptb may secrete immunoreactive proteins which are not dominant in long-term cultures.

Animals

Antibody reactivities of Mycobacterium paratuberculosis infected sheep as analyzed by enzyme-linked immunosorbent assay and western blotting.

Antibody reactivities in sera from Mycobacterium paratuberculosis (M. ptb) infected and vaccinated sheep were analyzed by enzyme-linked immunosorbent assay (ELISA) and Western (immuno)blotting using a sonicate antigen from M. ptb. Both methods allowed good differentiation between infected/vaccinated animals and noninfected controls. Removal of nonspecific crossreactive antibodies by absorption with a M. phlei sonicate antigen coupled to Sepharose reduced ELISA reactivities of positive sera by 50% and those of noninfected serum by 85%. Immunoblotting analysis revealed that reduction by M. phlei absorption was due to lower reactivities of M. ptb antigens in the range of 30 to 45 kDa. However, one protein with a molecular mass of approx. 27 kDa seemed to be specific for M. ptb since it reacted similarly with nonabsorbed and absorbed serum but not with antibodies which were eluted from M. phlei-Sepharose after absorption. Our findings indicate that M. ptb and M. phlei share a number of common antigens of potential pathogenic importance and that only a smaller part of proteins (i.e. the 27 kDa protein) might be specific for M. ptb.

Animals

Amplification and differentiation of the DNA of an abortigenic (type 1) and a respiratory (type 4) strain of equine herpesvirus by the polymerase chain reaction.

Unpurified DNA derived from cultures of equine fetal kidney cells infected with either equine herpesvirus type 1 or equine herpesvirus type 4 was amplified by the polymerase chain reaction using one pair of oligonucleotide primers. Restriction endonuclease digestion of the amplified segments with PvuII, followed by electrophoresis, revealed restriction fragment length polymorphisms which enabled the two virus types to be differentiated.

Abortion, Veterinary

In vitro and in vivo interaction between sporocysts of Sarcocystis muris and mouse peritoneal macrophages.

The interaction between the sporocysts of Sarcocystis muris and mouse peritoneal macrophages was studied both in vitro and in vivo in an attempt to determine whether or not resident peritoneal macrophages might effect the excystation of S. muris sporozoites from sporocysts injected intraperitoneally. Sporocysts of S. muris were phagocytosed by peritoneal macrophages both in vitro and in vivo. The addition of either unheated mouse serum or fetal calf serum did not significantly alter the level of phagocytosis. The percentage of phagocytosis in vivo and by thioglycolate-, proteose peptone- and BCG-elicited macrophages in vitro was greater than that shown by unstimulated macrophages in vitro. After 8 h incubation in vivo and in vitro a small proportion of sporocysts (less than 5%) was seen to have collapsed walls and up to 5% to have stained sporozoites, suggesting increased permeability of the sporocyst wall. The significance of increased permeability of the cyst wall in the process of sporozoite excystation is discussed.

Animals

Immunosuppression in Sarcocystis muris-infected mice: evidence for suppression of antibody and cell-mediated responses to a heterologous antigen.

Mice infected with Sarcocystis muris showed a significant reduction in plaque-forming cells (PFC) and delayed-type hypersensitivity (DHS) responses to an unrelated protein antigen, bovine gamma-globulin, when compared with uninfected controls. This immunosuppression was observed only when infection preceded immunization or when mice were immunized concurrently with infection, suggesting that suppression induced by murine sarcocystosis affected the induction and/or the differentiation of antigen-sensitive immunocytes. The immunosuppression lasted for 5 weeks, the period of this study, and affected cell-mediated responses more than antibody responses. The secondary PFC and DHS responses of mice immunized 14 days after infection and re-immunized 21 days later were also significantly lower than those of uninfected controls, whereas the secondary PFC and DHS responses of mice primed before infection were unimpaired. This indicated that S. muris infection affects only the induction but not the expression of immune memory.

Animals

Absence of lymphokine-enhanced macrophage migration in vitro in the Australian brush-tailed opossum, Trichosurus vulpecula.

The supernatants from cultures of either opossum or guinea pig splenic lymphocytes, stimulated with phytohaemagglutinin, significantly enhanced the in vitro migration of guinea pig peritoneal macrophages (P greater than 0.001) but not that of opossum peritoneal macrophages. Failure of opossum macrophages to respond to a putative macrophage chemotactic factor might account for the observed paucity of immune granulomas in these animals and help explain the species' susceptibility to tuberculosis.

Animals

Experimental trials on the use of radioimmunoassay for the detection of leptospiral antigens in urine.

Trials were conducted on the use of the solid phase radioimmunoassay (RIA) to detect leptospires or their antigens in simulated urine samples. The procedure was relatively simple to perform and appeared to be specific in detecting certain numbers of leptospiral organisms or their antigens in experimentally prepared samples. With this technique, it was possible to examine individual or pooled urine samples for the presence of leptospires within half a day. This technique may be of value for the detection of leptospiruric animals if the sensitivity of the technique could be further increased. Suggestions for the improvement of the procedure are discussed.

Animals

The magnitude and duration of titres of leptospiral agglutinins in human sera.

Sixty-nine meat inspectors with titres of leptospiral agglutinins ranging from 1:768 to 1:24, were re-bled and reexamined periodically over a period of 53 months. Some individuals maintained titres of 1:384 and 1:192 for at least 30 months and others with initial titres of 1:48 and 1:24 maintained such titres for 53 months. Only six, of 63 initially seronegative (less than 1:24) meat inspectors, seroconverted during the period of study. The magnitudes of titres at a single sampling from each of 162 people, with previous histories of medically confirmed leptospirosis, were analysed in relation to time elapsed since initial diagnosis. Some individuals had titres of 1:192 seven years after infection, while others had lower titres after more than 20 years. Conversely, 12% of the population was seronegative two years after infection. These results indicate that it is not possible, from the results of a leptospiral agglutination test, to estimate retrospectively the time at which infection may have occurred. In a small proportion of individuals recently affected by leptospirosis, it will not be possible to demonstrate a change in agglutinating titre.

Agglutination Tests

An immunological classification of ovine lymphomas.

Sporadic ovine lymphoma cells were identified as T or B lymphocytes with a T cell-specific antiserum or by detecting surface immunoglobulin. Lymphomas were classified as being of T or B cell origin if 60 per cent, or more, of the cells were of the respective type. Of 16 lymphomas, 6 were T cell and 6 were B cell derived. In one lymphoma more than 60 per cent of the cells were identified as both T and B cells. In the other 3 lymphomas neither T nor B cells reached this value; 2 of these had negligible T and B cell numbers and were classified as null cell lymphomas. A relationship was seen between the immunological and anatomical classifications of the lymphomas in that all the T cell lymphomas were of multicentric distribution while 4 of the 6 B cell neoplasms were confined to the alimentary tract and its associated lymphoid tissue. In contrast, there was no relationship between the immunological and histological classifications of the lymphomas.

Animals

Psychopharmacology. An historical perspective.

This article explores the field of psychopharmacology from an historical perspective. Part 1 traces the uses throughout history of psychoactive substances that are widely abused by modern society. Part 2 examines the development in the 1950s and 1960s of drugs and other physical methods that have revolutionized the treatment of the mentally ill.

Basidiomycota

The acute psychiatric diagnostic interview.

The general outline of a psychiatric diagnostic interview given in Table 1 includes some broad suggestions for the amount of time to spend on each section. As a structured interview based on a symptom checklist questionnaire yields higher frequency of reports of symptoms, it is advisable to follow this type of format rather than a totally unstructured interview technique. Sim recommends a structured format that lends itself to computerization. Griest and colleagues suggest a computer interview, and there are data supporting the diagnostic accuracy of such a system. Within the framework of any diagnostic interview, a thorough exploration of the 10 critical elements listed in Table 5 is essential for accurate diagnosis. This information, which is usually obtainable in about 30 minutes, will enable the clinician to make a preliminary diagnosis, decide upon pharmacotherapy, and determine if hospitalization is warranted. A more intensive but lengthy and time-consuming structured diagnostic interview is the Schedule for Affective Disorders (SADS), which is more appropriate for inpatients or patients being considered for a research protocol.

Acute Disease

Alpha-naphthyl acetate esterase activity is not a specific marker for ovine T lymphocytes.

Alpha-naphthyl acetate esterase (ANAE) activity was demonstrated in ovine lymphocytes harvested from blood on Ficoll-metrizoate gradients. The enzyme's specificity for T lymphocytes, identified by immunofluorescent staining of T cell-specific antigens, was assessed. Correlation analysis of the results obtained using unfractionated lymphocytes from 12 sheep showed no correlation between ANAE activity and the expression of T cell antigens (r = 0.22). When lymphocytes from 4 sheep were fractionated on nylon wool columns a mean of only 43.2% of the cells in the non-adherent population were ANAE-positive whereas 94.7% of these cells were identified as T lymphocytes. Blood lymphocytes from 5 animals were separated into 3 fractions using Percoll discontinuous density gradients. No significant relationship was seen between ANAE activity and T cells in Fractions 1 and 3 (r = 0.41 and 0.21). Fraction 2 cells, however, did show a significant positive relationship (r = 0.91) between these two features but the biological significance of this relationship is unknown. It was concluded that ANAE activity is not a specific marker for ovine T lymphocytes.

Animals

Polynesian bronchiectasis.

Six Polynesian children aged 8-14 years with recurrent lower respiratory infections and abnormal lung mucociliary clearance were assessed for immuno-deficiency. Measurements were made in these 6 children and in 21 healthy Polynesians of serum immunoglobulins (IgG, IgM, IgA) and complement components (C3, C4), leucocyte function tests, and T and B cell populations. A further 8 Polynesian bronchiectatics were tested for sputum secretory-IgA. There was no evidence of S-IgA deficiency and 4 had high levels. There was no evidence of immunodeficiency. Nasal epithelium was obtained from 6 children using a cytology brush and ciliated epithelium was obtained in only 4. The ultrastructure was normal although few cilia were examined.

Adolescent

Immunoglobulins of the Australian brush-tailed opossum, Trichosurus vulpecula.

Using standard methods IgG, IgM and (s) IgA were isolated from the serum or intestinal fluid of the Australian brush-tailed opossum, Trichosurus vulpecula. The molecular weights of the intact immunoglobulin molecules and their heavy and light chains were established. Two forms of IgG were seen which differed in their abilities to bind to insoluble matrices and also in their molecular weights. No antigenic differences were seen between them on analysis by agar diffusion. The molecular weights of opossum IgM and the two forms of IgG were similar to those of the corresponding immunoglobulins of man and other marsupials. However, the molecular weight of the IgA seen in intestinal fluid and results from its analysis by agar diffusion suggest that the molecule may lack secretory component.

Animals

Immunoglobulin levels in human colostrum and milk.

The levels of secretory IgA and of IgM and IgG in colostrums and milks obtained at various times postpartum were measured by radial immunodiffusion. Immunoglobulin A was the dominant immunoglobulin in all samples, and concentrations in colostrum ranged from 1.5 to 83.7 g/L (mean 32 g/L). Immunoglobulin M and IgG had mean colostrum concentrations of 1.13 and 0.53 g/L, respectively. Although the levels of each immunoglobulin declined with time postpartum, there was little change in the relative proportion of the immunoglobulin classes present.

Colostrum