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Biomedical subjects

M Gottschalk

Publications and source records attributed to M Gottschalk.

At least 73 records · Page 4Linked to original sources
PubMed1998

Development of an immunomagnetic method for selective isolation of Actinobacillus pleuropneumoniae serotype 1 from tonsils.

An immunomagnetic separation technique (IMS) for the selective isolation of Actinobacillus pleuropneumoniae serotype 1 was developed. Superparamagnetic polystyrene beads (immunomagnetic beads [IMBs]) were coated with purified rabbit immunoglobulin G specific for A. pleuropneumoniae serotype 1. The antibody concentration, the number of IMBs, the incubation time, and the temperature of incubation influenced the recovery of the target bacteria. The sensitivity of the IMS technique was 1,000-fold higher than that of direct culture. When tonsils from animals from infected herds were tested, significantly more positive tonsils were detected by the IMS technique (68%) than by the standard procedures (22%). The method represents an innovative and highly sensitive approach for the isolation of A. pleuropneumoniae from carrier animals.

Actinobacillus pleuropneumoniae↗
PubMed1998

Production of virulence-related proteins by Canadian strains of Streptococcus suis capsular type 2.

The production of muramidase-released protein (MRP), extracellular protein factor (EF) and hemolysin (suilysin) by 101 Canadian field strains of Streptococcus suis capsular type 2 is described. Most strains (72%) isolated from diseased pigs were MRP-EF- and only 1 strain was MRP+EF+. This strain was also the only 1 to produce the hemolysin. Thirteen strains (15%) were MRP+ EF- and only 3 strains were MRP* EF-. All the strains isolated from clinically healthy pigs as well as a bovine and 2 human isolates had a MRP-EF- phenotype. In addition, 7 strains (8%) had a MRPS phenotype, which had so far been described for S. suis capsular type 1. In conclusion, most Canadian field isolates of S. suis capsular type 2 tested in this study do not produce the virulence-related proteins described so far for this bacterial pathogen.

Animals↗
PubMed1997

Systematic home-based physical and functional therapy for older persons after hip fracture.

OBJECTIVE: To describe the development, implementation, and results of a home-based rehabilitation protocol for older persons after hip fracture. DESIGN: Demonstration study. SETTING: Community. PARTICIPANTS: One hundred forty-eight community-living, nondemented participants at least 65 years of age who underwent repair of a fractured hip at two local hospitals. INTERVENTION: A linked assessment-intervention, home-based rehabilitation strategy. The physical therapy (PT) component of the intervention was designed to identify and ameliorate impairments in balance, strength, transfers, gait, and stair climbing; the functional therapy (FT) component was designed to identify and improve unsafe and/or inefficient performance of specific activities of daily living (ADL). MAIN OUTCOME MEASURES: The percentage of participants able to complete each component and the extent of progress noted in strength, balance, transfers, gait, and daily functioning. RESULTS: A total of 104 of the 148 participants (70%) completed the 6-month PT and FT program; 4 completed only PT and 6 refused both PT and FT. The remaining 32 participants (22%) received partial PT and FT that was terminated by death, hospitalization, or institutionalization. Seventy-seven percent of participants reported performing at least half of the recommended daily exercise sessions. Ninety-four percent and 96% of participants progressed in upper and lower extremity conditioning respectively; 33% progressed to the highest level in the graduated resisted exercise program. All participants progressed in the competency-based graded balance program, with 55% progressing to the fifth (most difficult) level. Similarly, the majority progressed in transfer maneuvers, stair climbing, and outdoor gait. One repetition maximum (RM) elbow extension increased from a mean of 5.8 (SD 4.6) pounds at baseline to 7.2 (SD 3.8) pounds at 6mo (t 2.22; p < .02). One RM knee extension increased from 5.8 (SD 5.8) pounds to 10.8 (SD 5.4) pounds (t = 8.06; p < .0001). The number of gait deviations decreased from 2.1 (SD 1.3) to 0.6 (SD 0.9) (p < .0001), while the mean modified Berg Balance Scale Score increased from 13.0 (SD 4.8) to 20.5 (SD 6.8) (t = 16.6; p < .0001). Finally, the Total ADL Score increased from a mean of 48.2 (SD 15.0) to 77.7 (SD 18.8) (t = 17.03; p = .0001). CONCLUSIONS: This systematic assessment and intervention protocol, targeting impairments and ADL, was feasible, safe, and effective. Protocols such as the one presented should enhance the ability to implement rehabilitation programs for the increasing number of multiply impaired older persons receiving home-based therapy and to document the process and outcomes of this care.

Activities of Daily Living↗
PubMed1997

Detection of antibodies against Actinobacillus pleuropneumoniae serotype 5 using an inhibition enzyme immunoassay.

An inhibition enzyme immunoassay (EIA) for detection of antibodies against A. pleuropneumoniae serotype 5 (App-5) in pig sera, based on the inhibition of the binding of an App-5 specific monoclonal antibody was established. The monoclonal antibody (MAb 210-F11) was found to be directed against an epitope on the O-chain of App-5 LPS. In the inhibition EIA, highly purified App-5 LPS was used to coat microtitre plates. Serial dilutions of pig sera were added to the plates prior to the addition of the MAb 210-F11. The degree of binding of App-5 antibodies from pig sera was determined as the percentage inhibition of the MAb 210-F11. Pig serum from specific pathogen free (SPF) herds, from experimentally infected animals, and from acutely and chronically infected herds were tested. A serum dilution of 1/30 was found to be optimal, when using 50% inhibition as the discriminating inhibition percentage. No cross-reactivity was observed with serum from pigs infected with other App serotypes or bacteria isolated from the respiratory tract, such as A. suis and H. parasuis. The inhibition EIA will be used for surveillance of App-5 antibodies in SPF and conventional herds.

Actinobacillus Infections↗
PubMed1997

Serodiagnosis of swine pleuropneumonia due to Actinobacillus pleuropneumoniae serotypes 7 and 4 using long-chain lipopolysaccharides.

A saline boiled extract (SBE), capsular polysaccharides (CPS) and long-chain lipopolysaccharides (LC-LPS) of Actinobacillus pleuropneumoniae serotype 7 have been evaluated in ELISA for the serodiagnosis of swine pleuropneumonia caused by this serotype. Mean optical densities (ODs) obtained with the 3 antigens using sera from negative herds as well as from animals experimentally and naturally exposed to A. pleuropneumoniae serotypes 7 or 4 were not statistically different. The positive ELISA reaction with anti-serotype 4 sera was unexpected with the CPS, which are supposed to be serotype-specific; LPS traces present in the CPS appeared to be responsible for this reaction. In addition, sera from animals exposed to A. pleuropneumoniae serotypes 5 or 10 presented cross-reactions with the SBE and the CPS, but not with the LC-LPS. Cross-reactions were mainly due to rough LPS, as shown by immunoblotting. The LC-LPS is easily obtainable and can be used for the detection of antibodies in animals infected with A. pleuropneumoniae serotypes 7 and 4.

Actinobacillus Infections↗
PubMed1996

Detection of antibodies against Streptococcus suis capsular type 2 using a purified capsular polysaccharide antigen-based indirect ELISA.

In the present study a purified capsular polysaccharide antigen-based indirect ELISA (CPS-ELISA) to detect antibodies against Streptococcus suis capsular type 2 was developed and compared with a whole cell antigen-based ELISA (WCA-ELISA). The WCA-ELISA presented a very low specificity when rabbit antisera to other capsular types were tested. Most of these cross-reactions were due to common proteins. The standardized CPS-ELISA gave satisfactory results using a concentration of 0.1 micrograms/well; most cross-reactions decreased significantly, with some exceptions, such as those shared by capsular types 1/2, 12 and 17. These cross-reactions were mainly due to common epitopes present in the capsule, as shown by immunoblotting. In a second experiment, the CPS-ELISA was used to detect antibodies in experimentally infected piglets. Despite the fact that capsular type 2 S. suis could be reisolated from all infected animals during and/or after the trial, antibody titers against a second infection. Sera from piglets experimentally infected were completely protected against a second infection. Sera from piglets experimentally infected with S. suis capsular types 1/2 or 12 presented cross-reactions at low dilutions, confirming data previously obtained with rabbit sera. Finally, sera of animals from herds with clinical signs associated with S. suis capsular type 2 did not present titers significantly different from those of disease free herds. From our results we concluded that the CPS-ELISA developed in this study can not be used as a diagnostic tool to identify infected animals.

Animals↗
PubMed1996

In vitro phagocytosis and survival of Streptococcus suis capsular type 2 inside murine macrophages.

In this study, data on phagocytosis of Streptococcus suis and its survival inside macrophages are presented. Mouse peritoneal macrophages were incubated in the presence of one of five different strains of S. suis capsular type 2: a virulent wild-type strain (1591), a non-capsulated non-virulent mutant strain (M2), a poorly capsulated non-virulent mutant strain (M42), a non-virulent capsulated strain (1330), and the wild-type reference (virulent) strain S735. Opsonized or non-opsonized bacteria were incubated with macrophages in vitro and samples were obtained after 1 and 3 h incubation. Phagocytosis as well as live and dead intracellular organisms were determined by acridine orange and crystal violet staining. After 1 h incubation, non-opsonized virulent and non-virulent capsulated bacteria were poorly phagocytosed (by less than 7% of the macrophages), whereas the non-capsulated non-virulent mutant strain was highly phagocytosed (by more than 68% of the macrophages). The M42 mutant strain was more phagocytosed than the capsulated strains but less than the non-capsulated M2 mutant strain (35%). In contrast, a higher percentage of live bacteria was observed inside macrophages for the capsulated strains (1591 and S735) than for the non- or poorly capsulated mutant strains (M2 and M42). Opsonization of bacteria with rabbit serum or heat-inactivated rabbit serum significantly increased phagocytosis. For every opsonized strain, after 3 h incubation, the percentage of live bacteria within macrophages was considerably lower than the corresponding non-opsonized strains. In conclusion, the capsule of S. suis type 2 appears to act as an important anti-phagocytic factor. However, virulent capsulated non-opsonized strains can be phagocytosed by mouse peritoneal macrophages within which they appear to survive for at least 3 h. Serum factors other than complement increase not only phagocytosis but also intracellular killing of S. suis of both capsulated and non-capsulated strains.

Animals↗
PubMed1996

Role of capsular sialic acid in virulence and resistance to phagocytosis of Streptococcus suis capsular type 2.

Streptococcus suis capsular type 2 has a capsule rich in sialic acid (NANA). Sialic acid, known to be an antiphagocytic factor for many bacterial species, inhibits the activation of the alternative complement pathway. The role of capsular NANA in virulence, resistance to phagocytosis and intracellular survival of S. suis capsular type 2 was evaluated. In general, a low concentration of NANA was observed for all the S. suis strains tested. In addition, no difference could be found in NANA concentrations between strains of different virulence degrees. Sialic acid concentration increased in the virulent strain 89-1591 and the avirulent strain 90-1330 after in vivo growth with an increased capsular material thickness compared to growth in vitro. No significant difference could be found in the phagocytosis rate by porcine blood monocytes of either strain and strain 89-1591 treated with sialidase or the sialic acid-binding lectin from Sambucus nigra (SNA I). Intracellular survival of strain 89-1591 decreased after treatments with sialidase or lectin, becoming comparable to that of strain 90-1330. Finally, no difference could be seen in virulence using a murine model, even if strain 89-1591 was treated with the enzyme or the lectin. Thus, NANA does not seem to be a critical virulence factor for S. suis capsular type 2.

Animals↗
PubMed1996

Identification of two core types in lipopolysaccharides of Actinobacillus pleuropneumoniae representing serotypes 1 to 12.

Lipopolysaccharides (LPS) of Actinobacillus pleuropneumoniae were separated by Tricine-SDS-polyacrylamide gel electrophoresis, which has been shown to improve resolution of low-molecular-mass fast migrating bands. Strains representing the 12 serotypes of A. pleuropneumoniae can be divided in two groups according to the gel mobility of the core - lipid A region of their LPS. The first electromorphic core type (core type I), found in serotypes 1, 6, 9, and 11, had a migration slower than Salmonella typhimurium Ra LPS. The second electromorphic core type (core type II), found in the remaining serotypes (i.e., 2, 3, 4, 5, 7, 8, 10, and 12) had a migration similar to S. typhimurium Ra LPS. Furthermore, we observed that these two core types were antigenically different. Western blot analyses indicated that core - lipid A region of LPS from electromorphic core type I strains reacted when probed with serum from a pig experimentally infected with a core type I strain but not when probed with serum from a pig experimentally infected with a core type II strain. Conversely, core - lipid A region of LPS from electromorphic core type II strains reacted only when probed with serum from a pig experimentally infected with a core type II strain. Our results, based on both electrophoretic mobility and antigenicity, suggest the presence of two LPS core types in A. pleuropneumoniae.

Actinobacillus pleuropneumoniae↗
PubMed1996

Serotyping of Actinobacillus pleuropneumoniae serotype 5 strains using a monoclonal-based polystyrene agglutination test.

A polystyrene agglutination test has been developed for serotyping Actinobacillus pleuropneumoniae serotype 5a and 5b strains. Protein A-coated polystyrene microparticles were sensitized with a murine monoclonal antibody recognizing an epitope on serotype 5 LPS-O chain as shown by SDS-PAGE and Western blotting. A total of 205 A. pleuropneumoniae, strains including all 12 serotype reference strains and 13 strains representing 8 common bacterial species associated with swine or related to A. pleuropneumoniae, were tested by mixing 25 microL of polystyrene reagent with the same volume of a dense suspension of bacterial cells grown for 18 h. All A. pleuropneumoniae strains had been previously serotyped using standard procedures. The polystyrene agglutination test was rapid (less than 3 min) and easy to perform. Overall a very good correlation (97.3%) with the standard techniques was found. The sensitized polystyrene particles were stable for at least 6 mo.

Actinobacillus Infections↗
PubMed1995

Alterations in penicillin-binding proteins in strains of Streptococcus suis possessing moderate and high levels of resistance to penicillin.

We examined the penicillin-binding proteins (PBPs) of certain field strains of Streptococcus suis, as well as those from laboratory variants having different degrees of resistance to penicillin. Results indicated that (i) S. suis possesses three distinct groups of PBPs, arbitrarily named here PBP 1, PBP 2, and PBP 3, with approximate molecular weights of 97, 82, and 45 kDa respectively; (ii) PBP profiles of field strains of S. suis having different MICs (< or = 0.03) to 16.0 micrograms/ml) were not uniform (PBP 2 being difficult to detect in strains whose MICs exceeded 0.10 micrograms/ml, and PBP 3 which exhibited shifts in molecular weight of approximately 5 kDa); (iii) laboratory variant PBPs 1 and 2 showed decreased affinity for penicillin as compared to the parent strain in antibiotic competition experiments, even though the PBP profiles of both were similar. We suggest that PBP modifications (altered molecular weight and/or decreased affinity for penicillin) are involved in the mechanism of resistance to penicillin by S. suis.

Bacterial Proteins↗
PubMed1995

Production and characterization of monoclonal antibodies against Actinobacillus pleuropneumoniae serotype 1.

Three monoclonal antibodies (mAbs) against Actinobacillus pleuropneumoniae serotype 1, designated 4.2 A11 B5, 5.1 G8 F10 and 1.5 C5 F4 (IgG3, IgG2b and IgM respectively), were produced and characterized. mAbs 4.2 A11 B5 and 5.1 G8 F10 were directed against different epitopes located in the O chain of the LPS. Both clones also recognized reference strains of A. pleuropneumoniae serotypes 9 and 11. The mAb 1.5 C5 F4 reacted with the reference strain of A. pleuropneumoniae serotype 1, with the encapsulated strain 4045 (but not with its non-capsulated mutant) and with A. pleuropneumoniae serotype 1 purified capsular polysaccharides (CPS). The epitope was sensitive to periodate oxidation, heat-labile, and located in the capsular material of A. pleuropneumoniae serotype 1, as demonstrated by immunoblotting. Treatment of the CPS with 5% ammonium hydroxide eliminated the reaction, which may indicate that the epitope recognized by 1.5 C5 F4 mAb is a O-acetyl containing determinant. When different A. pleuropneumoniae field strains were tested, the percentage of strains recognized by the mAbs varied with the mAb and the test used. Cross-reactions associated with the LPS of some A. pleuropneumoniae serotype 5 field strains could be observed with the 4.2 A11 B5 mAb. Of the three mAbs characterized, 1.5 C5 F4 seemed to be the most suitable for A. pleuropneumoniae serotype 1 detection since it reacted with 99% of serotype 1 field strains and it did not recognize any of the strains belonging to other serotypes.

Actinobacillus pleuropneumoniae↗
PubMed1995

Agglutination of Streptococcus suis by sialic acid-binding lectins.

The 35 Streptococcus suis capsular-type reference strains as well as 45 field strains of type 2 were tested with sialic acid-binding lectins from Sambucus nigra (SNA I), Triticum vulgaris, Maackia amurensis, Homarus americanus, and Limax flavus. Only types 1, 1/2, 2, 14, 15, and 16 agglutinated with SNA I and/or the T. vulgaris lectin. All field strains agglutinated only with SNA I. Reaction with SNA I was probably due to the sialic acid moiety since it disappeared after sialidase treatment. These results confirm the presence of sialic acid in S. suis with the possible terminal sequence N-acetylneuraminic acid-alpha(2,6)GalNAc.

Agglutination Tests↗
PubMed1995

Streptococcus pneumoniae types 19A and 19F and Streptococcus suis capsular type 8 share common capsular epitopes.

Two monoclonal antibodies (MAbs) to Streptococcus pneumoniae types 19A and 19F were tested with the 35 reference strains and 334 field strains of Streptococcus suis by dot blotting. Both MAbs reacted with the capsular type 8 reference strain, and one reacted with 69% and one reacted with 100% of 81 S. suis capsular type 8 field strains tested. Epitopes recognized by both MAbs are capsular in origin.

Antigens, Bacterial↗