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Biomedical subjects

G Mazza

Publications and source records attributed to G Mazza.

At least 55 records · Page 3Linked to original sources
PubMed1996

Does the presence of ANCA in patients with ulcerative colitis necessarily imply renal involvement?

BACKGROUND: ANCA are thought to play a pathogenic role in renal vasculitis. ANCA may also be detected in patients with diseases not usually associated with renal pathology, such as ulcerative colitis. Our study was conducted to determine if the presence of ANCA in patients with ulcerative colitis is associated with renal pathology. METHODS: Eight ANCA-positive and five ANCA-negative patients with a histological and endoscopic diagnosis of active ulcerative colitis were investigated. Repeated complete urinalyses and determination of microalbuminuria and creatinine clearance were performed. Serum IgG and IgA ANCA were evaluated in all patients by indirect immunofluorescence and ELISA, and when detected the antibodies were further characterized by alpha granules preparation, myeloperoxidase, lactoferrin, and cathepsin G. RESULTS: In both ANCA-positive and ANCA-negative patients renal function was normal or near normal and urinalyses (including microalbuminuria) failed to disclose any abnormalities. ANCA exhibited a perinuclear pattern in all ANCA-positive patients. Interestingly, none of the ANCA-positive patients had antibodies to myeloperoxidase or to alpha granules which are usually found in the sera of patients with ANCA-associated vasculitis, and only one had antibodies to lactoferrin. The ANCA specificity remained undetermined in the remaining seven patients. At the end of the 1-year observation period, all ANCA-positive patients remained ANCA-positive without developing symptoms, signs or laboratory abnormalities consistent with renal involvement. CONCLUSIONS: Renal damage was not observed in ANCA-positive patients with ulcerative colitis even after 1 year of follow-up, suggesting that the ANCA found in these patients do not share the antigenic targets with the ANCA commonly found in renal vasculitis. Therefore the potential of ANCA of inducing renal lesions (if any) is dependent on their own antigenic specificity.

Adolescent↗
PubMed1996

Quantitation of erythrocyte-bound IgG subclass autoantibodies in murine autoimmune haemolytic anaemia.

A quantitative and sensitive cellular enzyme-linked immunosorbent assay was developed for determining the number of molecules of IgG of each subclass bound to the surface of murine red blood cells (RBC). To develop standard titration curves, RBC from normal mice were treated with tannic acid and coated with a known concentration of purified myeloma of each IgG subclass. The quantity of each subclass bound to the surface of erythrocytes was determined by calculating the protein concentration of the bound IgG, which was then converted into number of molecules of IgG/RBC. The assay was used to quantify the number of autoantibodies of all four IgG subclass bound to the erythrocytes of mice injected with rat RBC. Twenty one days after the first immunisation, a mean number of 84,000 molecules of IgG1/RBC were detected, which increased to 114,500 molecules/RBC on day 28. On days 56 and 96 the mean concentration of IgG1 remained high, however by day 110 the mean level of IgG1 had decreased slighty to 69,500 molecules/RBC. By contrast, the mean concentration of IgG2a autoantibodies was considerably lower throughout the experiment, starting at 40,200 molecules/RBC on day 21 and dropping to 2,500 molecules/RBC by day 110. The mean quantities of IgG2b and IgG3 autoantibodies were similar to each other, and intermediate between the levels of IgG1 and IgG2a autoantibodies.

Anemia, Hemolytic, Autoimmune↗
PubMed1995

Tissue immunoglobulin G subclasses observed in immune-mediated dermatopathy, deep pyoderma and hypersensitivity dermatitis in dogs.

A panel of monoclonal antibodies has been used to define three of the four subclasses of canine immunoglobulin G (IgG2, IgG3 and IgG4) in formalin-fixed tissues. These reagents, together with a polyclonal antiserum specific for the Fc region of canine IgG, were used in an immunohistochemical study of biopsies of skin from five normal dogs and from the lesions of canine pemphigus foliaceus in seven dogs, discoid lupus erythematosus in eight dogs, bullous pemphigoid in one dog, cutaneous drug eruption in two dogs, deep pyoderma in 13 dogs and hypersensitivity dermatitis in eight dogs. IgG autoantibody was identified in the skin of all the dogs with immune-mediated dermatoses by using the polyclonal reagent, and antibody of the IgG2 and/or IgG4 subclass was identified in the epidermis of three of the dogs with pemphigus foliaceus, two of those with discoid lupus erythematosus and in the dog with bullous pemphigoid. In all the lesions, the infiltrate of dermal plasma cells consisted of similar numbers of IgG2 and IgG4 bearing cells, with relatively few IgG3 positive cells. The total number of these cells was generally approximately the same as or greater than the number of cells labelled with the polyclonal reagent. There was no significant difference between the IgG-bearing plasma cell infiltrate in German shepherd dogs with deep pyoderma and that in dogs of other breeds. The infiltration of IgG2 and IgG4 bearing plasma cells into the skin of dogs with a range of cutaneous disorders was related to the selectively enhanced serum levels of these subclasses in the diseased dogs.

Animals↗
PubMed1995

Anthocyanins in grapes and grape products.

The types of anthocyanins occurring in grapes, wines, and juices are described and their distribution documented. Recent work on the evaluation of red wine color during storage and aging is reviewed. Molecular interactions between anthocyanins and some of the other red wine molecules are shown to be associated with development of new pigments whose formation explains the subtle color changes and stabilization occurring on aging of red wines. A detailed description of the recovery of anthocyanins from grape pomace and production of natural red colorants is also given.

Anthocyanins↗
PubMed1994

Development of an enzyme-linked immunosorbent assay for the detection of IgG subclasses in the serum of normal and diseased dogs.

The present study describes the development of an enzyme-linked immunosorbent assay capable of quantifying serum antibody of all four canine IgG subclasses. A panel of subclass-restricted and subclass-specific monoclonal antibodies was used to measure IgG subclasses in the serum of healthy dogs, as well as in dogs with a range of clinical diseases. The subclasses have been redefined as IgG1, IgG2, IgG3 and IgG4 based on a comparison with the relative concentration and electrophoretic mobilities of human IgG subclasses. In serum samples from healthy dogs, the concentration of IgG1 (mean, 8.17 +/- 0.95 mg ml-1) and IgG2 (mean, 8.15 +/- 3.16 mg ml-1) were very similar and considerably higher than the levels of IgG3 (mean, 0.36 +/- 0.43 mg ml-1) and IgG4 (mean, 0.95 +/- 0.45 mg ml-1). There was no apparent difference in the level of subclasses between the different breeds comprising this normal population. Sera from dogs with a range of immune-mediated or inflammatory diseases all had markedly elevated levels of IgG2 (more than 13 mg ml-1), but IgG1 decreased (less than 4 mg ml-1) to levels below the normal range.

Anemia, Hemolytic, Autoimmune↗
PubMed1994

Preparation of monoclonal antibodies specific for the subclasses of canine IgG.

Canine IgG is composed of four subclasses, which are defined as IgG1, IgG2, IgG3 and IgG4 on the basis of data from fast protein liquid chromatography, and their electrophoretic mobilities and relative concentrations in serum. This paper describes the preparation of mAbs specific for determinants on canine IgG2, IgG3 and IgG4. The mAb specific for IgG2 resulted from a conventional immunisation protocol. The mAb specific for IgG3 was a result of immunisation with IgG3 combined with the suppression of the immune response to IgG1 by passively administered anti-IgG1 antibody. The mAb specific for IgG4 resulted from immunisation with Fab or Fc fragments which were obtained by the cleavage of the IgG4 molecule with papain. The specificity of each mAb was established by using an enzyme-linked immunosorbent assay which showed that all three specific clones recognised a determinant in the Fd region of the canine immunoglobulin molecule.

Animals↗
PubMed1993

The separation and identification by monoclonal antibodies of dog IgG fractions.

Four fractions of IgG from normal dog serum have been successfully isolated by gel filtration followed by protein A and protein G affinity chromatography using the fast protein liquid chromatography (FPLC) system. Protein A chromatography produced three peaks: peak 1 was fallthrough material consisting of components which did not bind to protein A, peak 2 consisted of bound material eluting at pH 6, and peak 3 contained bound material eluting at pH 3.5. The three peaks were then subjected individually to protein G affinity chromatography. Peak 1 from protein A chromatography produced a fallthrough peak followed by a weakly binding component which eluted at pH 8, and was called peak w. Peak 2 from protein A chromatography bound to protein G and eluted as a single peak at pH 3.8, and was called peak x. Peak 3 from protein A chromatography emerged as two separate peaks (y and z) off the protein G column; peak y bound and eluted at pH 4.1, and peak z bound weakly to protein G and emerged as a broad band at pH 8. Peaks w, x, y and z have been named gamma w, gamma x, gamma y and gamma z, respectively, and there purified IgG fractions were used to immunize mice for the preparation of monoclonal antibodies (McAbs). To date, two sets of McAbs have been produced: one which recognizes an epitope present in both gamma w and gamma z fractions and another set of McAbs which recognizes an epitope in the gamma x and gamma y fractions.

Animals↗
PubMed1993

T cell development in mice lacking the CD3-zeta/eta gene.

The CD3-zeta and CD3-eta polypeptides are two of the components of the T cell antigen receptor (TCR) which contribute to its efficient cell surface expression and account for part of its transducing capability. CD3-zeta and CD3-eta result from the alternative splicing of a single gene designated CD3-zeta/eta. To evaluate the role of these subunits during T cell development, we have produced mice with a disrupted CD3-zeta/eta gene. The analysis of thymocyte populations from the CD3-zeta/eta-/- homozygous mutant mice revealed that they have a profound reduction in the surface levels of TCR complexes and that the products of the CD3-zeta/eta gene appear to be needed for the efficient generation and/or survival of CD4+CD8+ thymocytes. Despite the almost total absence of mature single positive thymocytes, the lymph nodes from zeta/eta-/- mice were found to contain unusual CD4+CD8- and CD4-CD8+ single positive cells which were CD3-. In contrast to the situation observed in the thymus, the thymus-independent gut intraepithelial lymphocytes present in zeta/eta-/- mice do express TCR complexes on their surface and these are associated with Fc epsilon RI gamma homodimers. These results establish an essential role for the CD3-zeta/eta gene products during intrathymic T cell differentiation and further emphasize the difference between conventional T cells and thymus-independent gut intraepithelial lymphocytes.

Animals↗
PubMed1993

Isodicentric Philadelphia chromosome in accelerated phase of chronic myeloid leukemia.

We describe a case of chronic myeloid leukemia (CML) associated with the finding of an isodicentric Philadelphia chromosome [idic(Ph)] during the accelerated phase of the disease. Chromosome study was carried out on bone marrow aspirate cells, obtained and cultured 5 months after the clinical diagnosis. The presence of an isodicentric Philadelphia chromosome was found in 90% of the analyzed metaphases; among the remaining observed metaphases, 6% showed two idic(Ph) chromosomes, 2% a t(9;22), and 2% a normal karyotype. The patient died 7 months after the clinical diagnosis, and 2 months after our chromosome study. The observation of idic(Ph) during CML has seldom been reported and the few cases studied have been inconsistently correlated with the course of the disease. In the present case, the finding of an idic(Ph) and the short patient survival from the time of clinical diagnosis may suggest the observed chromosome aberration as a factor associated with a poor prognosis.

Aged↗
PubMed1993

Iontophoresis of drugs in the bladder wall: equipment and preliminary studies.

Iontophoresis is the active transport of ions into tissues by means of an electric current: Ji = -D(i)delta Ci/delta chi + DizeECi/kT. Where Ji is the total ionic flux, D(i) the diffusion coefficient, Ci the concentration, z the valency, and E the electric field. The first expression on the right side of the equation is Fick's law of diffusion and approaches zero for bladder mucosa, which leads to uncertain results following intravesical administration of various therapeutic agents. The application of an electric field will potentially accelerate drug administration into the bladder wall in a controllable manner. To evaluate this concept, an appropriate source of electric current and electrodes was fabricated; then, studies were conducted in human cadaveric bladders and clinical trials in human subjects. Ionized dyes were applied in duplicate to 10 fresh cadaveric bladders. Electric currents (3.5-5.0 mA) were applied for 20 min to 10 solutions, and no current was used in 10 controls. Twenty-eight patients had 100 ml solutions of 1% mepivacaine or lidocaine with epinephrine infused into their bladders prior to endoscopic resections. Twenty-two patients received currents of 10-20 mA for 10-20 min, and 6 controls had either no drugs or a current of reverse polarity applied. Visually and on microscopy, the 10 control cadaveric bladder surfaces demonstrated only faint staining of the surface mucosa whereas the experimental surfaces showed full-thickness staining of the mucosa extending into the muscularis. The 6 control patients required supplemental anesthesia or abandonment of the operative procedure. Of the 22 experimental subjects, 16 tolerated procedures with up to 25 g of tissue removed by diathermic resection.

Administration, Intravesical↗
PubMed1991

Engineered secreted T-cell receptor alpha beta heterodimers.

We have produced a soluble form of a mouse alpha beta T-cell antigen receptor (TCR) by shuffling its variable (V) and constant (C) domains to the C region of an immunoglobulin kappa light chain. These chimeric molecules composed of V alpha C alpha C kappa and V beta C beta C kappa chains were efficiently secreted (up to 1 micrograms/ml) by transfected myeloma cells as noncovalent heterodimers of about 95-kDa molecular mass. In the absence of direct binding measurement, we have refined the epitopic analysis of the soluble V alpha C alpha C kappa-V beta C beta C kappa dimers and shown that they react with an anti-clonotypic antibody and two antibodies directed to the C domain of the TCR alpha and beta chains. Conversely, we have raised three distinct monoclonal antibodies against the soluble TCR heterodimers and shown that they recognize surface-expressed TCRs. Two of these antibodies were found to react specifically with the products of the V alpha 2 (V delta 8) and V beta 2 gene segments, respectively. When considered together, these data suggest that these soluble TCR molecules are folded in a conformation indistinguishable from that which they assume at the cell surface.

Amino Acid Sequence↗
PubMed1991

The presence of eosinophil-activating mediators in sera from individuals with Schistosoma mansoni infections.

IgG antibodies and eosinophils kill schistosomula of Schistosoma mansoni in vitro, and there is now evidence to suggest that the main factor that contributes to the expression of purified IgG effector function is the degree of activation of the donor's eosinophils. This study was designed to identify serum-derived activating factors in sera from individuals infected with S. mansoni. Such activating factors may be responsible for enhancing eosinophil cytotoxicity against schistosomula. Serum-borne mediators were prepared by fractionation of sera from infected individuals by gel filtration high-performance liquid chromatography. The eosinophil-stimulating activity of these mediators was assayed by a new method which depends on the increased expression of the CR3 alpha chain (CD11b) on the surface of activated eosinophils. Sera from infected individuals exhibited different levels of eosinophil activation, and activation appeared to be due to several serum factors, including interleukin 5. In conclusion, our results suggest that eosinophil-activating factors present in infection sera may not only be responsible for enhancing eosinophil cytotoxicity but also be necessary for its expression.

Cytotoxicity, Immunologic↗
PubMed1991

Seroepidemiology of pertussis infection in an urban childhood population in Cameroon.

In 1989, the prevalence of IgG antibodies to pertussis toxin (PT) in a sample of 367 unvaccinated apparently healthy children 5-14 years old was estimated by ELISA in Kumba City (Cameroon). Children were recruited using a systematic random sampling from six primary schools located in different districts of the city. The sample was representative of the various socioeconomic classes. The overall prevalence was 75%; it increased from 62% in 5 year old children to 81% in children 12-14 years old (P less than 0.01). IgG antibody prevalence was positively related to the family size. Children belonging to households of nine or more members had a 2.2-fold risk (C.I. 95 per cent = 1.1-4.6) of previous exposure to B. pertussis infection. No association was found with the father's occupation (O.R. = 1). These findings demonstrate a great impact of pertussis infection in Cameroon, with a nearly total exposure by late childhood.

Adolescent↗
PubMed1990

A new method for measuring eosinophil activating factors, based on the increased expression of CR3 alpha chain (CD11b) on the surface of activated eosinophils.

The observation that activation of eosinophils in vitro with PAF increases the surface expression of the alpha chain of the complement receptor CR3 (CD11b) has been extended to other eosinophil activating factors. CD11b may be detected on activated eosinophils by reaction with mouse monoclonal anti-human CD11b IgG, following the addition of urease-conjugated sheep anti-mouse IgG. CD11b levels were increased on eosinophils after incubation with (a) recombinant colony stimulating factors, IL-3, GM-CSF and IL-5, at concentrations of 100 U/ml, or (b) with eosinophil activating factors, recombinant TNF alpha (1000 U/ml), EAF purified from mononuclear cell supernatants and PAF (10(-6) M). CD11b levels were not affected by IL-1 alpha, IL-2 or IFN-gamma. Unstimulated neutrophils had higher levels of CD11b than unstimulated eosinophils, but neutrophil CD11b was unaffected by IL-3, GM-CSF and IL-5 and was only slightly affected by TNF, EAF and PAF. Polyclonal rabbit antibodies to IL-3 and TNF neutralised their CD11b enhancing activities. The PAF antagonists WEB 2086 and WEB 2170 neutralised the CD11b enhancing activity of PAF. We conclude that measurement of CD11b expression on eosinophils is a convenient method for the assay of eosinophil activating activity.

Animals↗
PubMed1990

Poly(Glu60Ala30Tyr10) (GAT)-induced IgG monoclonal antibodies cross-react with various self and non-self antigens through the complementarity determining regions. Comparison with IgM monoclonal polyreactive natural antibodies.

Previous studies have shown that the antibodies of the preimmune repertoire are able to bind to various auto- and xenoantigens including chemical haptens. Sequence analysis of two such murine monoclonal IgM natural autoantibodies showed that they are encoded by unmutated germ-line variable regions of the light and heavy chain (V alpha and VH) genes which were also found in various murine immune responses, like phenyl-oxazolone, dinitrophenyl, arsonate, phosphorylcholine and influenza virus hemagglutinin. These data raised the question as to whether induced antibodies possessing germ-line sequence are also able to react with autoantigens. To study this problem, anti-poly(Glu60Ala30Tyr10) (GAT) and anti-alprenolol (Alp) monoclonal antibodies, carrying similar VH and V alpha genes and the same IgG1 isotype, were examined for their capacity to react with several self and non-self antigens. The results showed that: (a) the anti-GAT antibodies tested reacted with different autoantigens, such as murine tubulin, actin and myosin as well as trinitrophenyl (TNP) and bovine serum albumin. Similarly, one of the anti-Alp showed weak reactivities for myosin, DNA, actin and TNP; (b) in contrast two other anti-Alp antibodies did not react with any of the tested antigens. Since the major differences between the oligoreactive anti-GAT and the monoreactive anti-Alp antibodies are in the complementarity determining regions (CDR) our results suggest that the observed cross-reactions are mediated by hypervariable loops. Sequence comparison of these antibodies indicate a possible correlation between cross-reactivity and the presence of aromatic and charged amino acids in the CDR.

Amino Acid Sequence↗
PubMed1990

Antibody isotype responses to the Schistosoma mansoni schistosomulum in the CBA/N mouse induced by different stages of the parasite life cycle.

During infection with Schistosoma mansoni the extent and nature of immune reactions against schistosomula may be influenced by responses to cross-reactive antigens in eggs or adult worms, and there is now extensive evidence for cross-reactivity between the different stages of the parasite life cycle. In this study IgM and IgG subclass antibodies produced in (CBA/N x Balb/c) F1 male and female mice were measured over a period of time following exposure to a chronic infection, to unisexual male cercariae or to irradiated larvae. Antibody levels were also measured following immunization with antigen preparations derived from adult worms, schistosomula or eggs. (CBA/N x Balb/c) F1 male mice exhibit an X-linked immune deficiency which results in an inability to respond to T-independent (TI) type 2 polysaccharides. Isotype levels were measured by ELISA to detergent-soluble schistosomulum antigen. Results showed that antigens on the different stages of the parasite life cycle have a qualitative influence on the antibody response to the larval surface, and that T-independent type 2 polysaccharides, particularly abundant in egg, exhibit antigen-directed isotype restriction in the form of IgM and IgG3 antibodies.

Animals↗