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M Petcovici

Publications and source records attributed to M Petcovici.

At least 19 recordsLinked to original sources
PubMed1982

Isolation and characterization of a cross-reacting antigen in strains of Bacteroidaceae.

A Bacteroidaceae cross-reacting antigen (BCA) was isolated from several strains belonging to species in the genera Fusobacterium and Bacteroides. We showed that each of the 28 strains examined synthesized either BCA or the O-specific lipopolysaccharide (LPS). The structural difference between the two antigens was demonstrated by passive hemagglutination. BCA coated erythrocytes spontaneously and reacted with equal intensity to all bacterial antisera of BCA+ strains, whereas LPS was species specific and also coated erythrocytes after the antigen was treated with NaOH. BCA is an acid polysaccharide as proven by immunoelectrophoresis and by its capacity to form a salt linkage with lysozyme. Chemical analysis demonstrated the presence of galactosamine, glucosamine, galactose, glucose, mannose, and N-acetyl. BCA was nontoxic and did not contain lipid A in its molecule. The small particle size of BCA determined its hapten character. When attached to acid-treated Salmonella minnesota Re cells, it acted as an immunogen. By immunizing rabbits with this hapten-bacterial cell suspension, we obtained a highly potent antiserum that agglutinated all BCA+ strains.

Antigens, Bacterial↗
PubMed1977

Demonstration of enterobacterial common antigen by bacterial agglutination.

Potent antisera against the enterobacterial common antigen (ECA) agglutinate R bacteria of the Enterobacteriaceae family that possess unimpaired R-core structures of the Escherichia coli R1 or E. coli R4 core type. In these strains, known to be ECA immunogenic, ECA is most probably linked to the lipopolysaccharide R core. R mutants of other core types (e.g., Salmonella Ra, E. coli R2 or R3) or R mutants with incomplete core structures of the E. coli R1 type, as well as an rfaL mutant deficient in the O-translocase system, agglutinate to a much lesser extent or not at all. All the later mutants are nonimmunogenic; they possess the ECA in a free form, not linked to the R core. None of the S forms tested from many different enterobacterial genera was found to be agglutinable with the ECA antiserum. The dynamics of the ECA agglutinin formation in rabbits parallels the ECA hemagglutinin formation, indicating that the same antibody class might be involved in bacterial agglutination and hemagglutination.

Agglutination↗
PubMed1976

Role of the rfa locus in the immunogenicity of common enterobacterial antigen.

Escherichia coli O14 is one of the few strains of Enterobacteriaceae which in the rabbit engender antibodies in high titers against the common enterobacterial antigen (CA). It is a rough strain that does not possess a specific side chain in its lipopolysaccharide structure (rfa+rfb-). An rfa mutant (rfa-rfb-) was isolated from this parental strain. Chemical analysis revealed the absence of one glucose and of one galactose molecule in the core polysaccharide of the mutant. The incomplete synthesis of the core was accompanied by loss of immunogenicity of CA. In the mutant, in contrast to the wild type, CA was not bound to the core; hence, the core lipopolysaccharide might exert immunosuppressive activity on CA. A protein fraction of normal rabbit serum was shown to destroy the erythrocyte-coating capacity of CA. This fraction also displayed immunosuppressive activity on free CA but not on CA bound to the core polysaccharide.

Animals↗
PubMed1975

Immunochemical studies on purified common enterobacterial antigen (KUNIN).

A common antigen (KUNIN) purification method is described. The preparation obtained was highly antigenic, as proved by hemagglutination and its inhibition, and immunogenic in rabbits. Chemical analysis demonstrated the presence of an L-phosphoglycerid of the cephalin type, of protein, glucosamine, acetyl and glucose. The antigen had the character of an acidic polymer. It readily forms salt linkages with lysozyme. Phospholipase A induced the release of myristic, palmitic and stearic acids. It also destroyed both the antigenicity and immunogenicity of common antigen.

Animals↗
PubMedDate not supplied

[Alpha 1-antitrypsin, alpha 2-macroglobulin and reactive protein C in gastric cancer].

Proteins of acute phase: alpha 1-antitrypsin (AAT), alpha 2-macroglobulin (AMG), reactive C protein (RCP) were determined in the serum of 50 patients with gastric cancer. The Mancini, simple radial immunodiffusion method was used (SRID). The concentration of these proteins increased at 32/50 (64%) for AAT; 30/50 (60%) for AMG and 33/50 (66%) for RCP. By cumulative evaluation, the positivity of serum markers increased to 88%. The importance of differential diagnosis with regard to the benign gastric lesions (adenoma, ulcer, segmentary fibrosis, before receiving the bioptic result, is emphasized.

Adenocarcinoma↗
PubMedDate not supplied

Quantitative profile of cardiolipin and group treponemal IgD antibodies in syphilis estimated by single radial immunodiffusion technique (SRID).

150 serum samples (reactive in VDRL, Reiter-ELISA, FTA-Abs tests), from male patients 25-45 years old, in various stages of syphilis whether treated or untreated, were tested for IgD by SRID. On 154 sera from healthy males 25-45 years old, the reference normal values for IgD levels were established, as: 0-131.2 IU/ml with a mean of 29.92 +/- 29.61 IU/ml. Cardiolipin and group treponemal fraction values for IgD class were obtained by assessing the difference between the immunodiffusion diameter values produced by sera before and after complete absorption with VDRL antigen or delipidated T. reiteri suspension. The individual, mean +/- SD values (expressed in IU/ml) and the percentage of cardiolipin and treponemal IgD of the total IgD class were calculated for each stage. The mean value of the total IgD class, excepting secondary syphilis (sigma 2) 52.53 +/- 26.66 IU/ml), did not overstep the normal levels but all minimal individual values from syphilitic patients (7.09-14.89 IU/ml) surpassed significantly the normal minimal values which were less than or equal to 3.54 IU/ml. The total lack of cardiolipin (IgD and the presence of group treponemal IgD in all sera of the syphilis stages studied were manifest. The group treponemal IgD mean values ranged between 7-9 IU/ml, with a maximum of 19.32 +/- 10.58 IU/ml in sigma 2 followed by latent syphilis (sigma lat) with a mean value of 9.37 +/- 4.9 IU/ml. A significant percentage of treponemal IgD vs total IgD was recorded: primary syphilis (sigma 1) 32.01%, primary-secondary syphilis (sigma 1-2) 28.76%, sigma 2 36.77%, sigma lat and treated persistent seroreactive syphilis (sigma t+) 29.61%. The high proportion of treponemal IgD in latent and treated persistent reactive syphilis suggests a steady activation of B lymphocytes by treponemal antigens and presumably is an expression of an active infectious process. The absence of cardiolipin IgD and the presence of only the treponemal IgD, in all sera from all stages, might confer to their detection an extremely specific diagnostic value in syphilis.

Adult↗
PubMedDate not supplied

Isolation of anti-carcinoembryonic antigen (CEA), specific immunoglobulins and their use in immunocytochemical and enzyme-immunoassays (ELISA).

Anti-carcinoembryonic (CEA) polyclonal antibodies in sheep and rabbits were raised using purified CEA from acid extracts of human colon adenocarcinoma. CEA was purified by gel filtration on Sepharose 4B CL and chromatography on DEAE-Sephadex A50. The antiserum was adsorbed with human serum and perchloric acid extract from normal colon. Anti-CEA IgG was purified from monospecific antiserum by ion-exchange chromatography and its specificity was tested on cryostat sections from colon adenocarcinoma by the indirect immunoperoxidase technique. The specific reaction was compared with that obtained by using a similar technique and two CEA specific monoclonal antibodies. An anti-CEA IgG peroxidase conjugate was obtained allowing to establish a "sandwich" ELISA-CEA system with two antibodies. CEA determinations were made in a group of 15 normal controls (mean value 4.8 +/- 0.4 ng/ml) and in 30 colorectal tumor patients (mean value 26.6 +/- 2.15 ng/ml). The anti-CEA antibodies are proven useful in immunocytochemical and ELISA techniques and may be further used in radioimaging of tumors.

Adenocarcinoma↗
PubMedDate not supplied

[The isolation of anti-carcinoembryonic antigen (CEA) immunoglobulins and their use in immunocytochemical and immunoenzyme (ELISA) technics].

Carcinoembryonic anti-antigen (CEA) polyclonal antibodies were obtained in ram and rabbit using as antigen source the extracts with perchloric acid from the human colon adenocarcinomas. CEA was purified by gel filtration on Sepharose 4BCL and ion-exchange chromatography (DEAE-Sephadex A50). The total antiserum was absorbed with human serum and perchloric acid extract from the normal colon. IgG anti-CEA was purified by chromatography of the monospecific antiserum, then tested for bonding specificity, at cryostat on sections of colon adenocarcinoma, by indirect immunoperoxidase. The specific reaction was compared with that obtained by the same technique, using two monoclonal antibodies specific to the CEA molecule (MAb-26/3/13 and MAb-26/5/1 respectively). IgG anti-CEA was also used for obtaining some IgG-peroxidase conjugates, with an immunoenzymatic system, ELISA type, with two antibodies according to the model of the ELISA kits produced by the Cantacuzino Institute (ELISA-AFP). The ELISA-CEA kit was standardized using an international CEA standard. CEA was quantitatively determined with this immunoenzymatic system (ELISA-CEA) on a group of 15 healthy subjects (average: 4.8 +/- 0.12 ng/ml) and on 30 patients with colorectal tumours (average: 26.6 +/- 0.15 ng/ml). ELISA-CEA kit, sensitive and reproducible, allow the usual quantitative determination of CEA, a useful marker in diagnosing and monitoring tumour evolution.

Antibody Specificity↗
PubMedDate not supplied

Quantitative determination of rheumatoid factors in serum and synovial liquid of patients with rheumatoid arthritis using lyophilized standard products.

The rheumatoid factors constitute one of the major autoantibodies in rheumatoid arthritis (RA). In this study, for the quantitative determination of the RF IgM class, in serum and synovial liquid of patients with RA and JRA, we used the hemagglutination principle and both liquid and lyophilized reagents. The results we obtained demonstrated the superiority regarding the stability, the reproducibility and the possibility of micromethod standardization with lyophilized reagent.

Adolescent↗
PubMedDate not supplied

[Heterophile antibodies].

After a short history and definition of the heterophile antibodies (antibodies in the IgM class, reacting to the antigenic determinants common to several species of animals) the paper reports on the antigens generating heterophile antibodies: the Forssman antigen, the Hanganutziu-Deicher antigen, the Paul-Brunnell antigen, respectively. Data are presented on the structure of these antigens and the important in diagnosing the heterophile antibodies in a series of diseases: malignant tumours, lymphomas, leukemias, infections mononucleosis, rheumatoid polyarthritis, Kawasaki's disease, Marek's disease.

Animals↗