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Biomedical subjects

M Campa

Publications and source records attributed to M Campa.

At least 19 recordsLinked to original sources
PubMed2006

Serological diversity demonstrable by a set of monoclonal antibodies to eight serotypes of the mutans streptococci.

A set of monoclonal antibodies were prepared by the conventional cell fusion of myeloma cells (SP2/0-Ag14) with spleen cells from BALB/c mice immunised with whole cells of a strain of mutans streptococci. Their specificities were examined against 35 reference strains of mutans streptococci, 34 reference strains of other oral streptococci and 8 reference strains of other microorganisms often inhabiting the oral cavity. Specificity was examined by enzyme immunoassay using whole cells. A total of 52 strains, consisting of 19 strains isolated in Japan, 19 strains isolated in Italy and 14 strains isolated in England, were characterised by conventional physiological and biochemical tests and then serotyped by the use of 8 monoclonal antibodies with different specificities. They were also confirmed by guanine-plus-cytosine contents of their nucleic acid and DNA-DNA hybridisation test. The results indicated that all monoclonal antibodies are useful for identification of 8 serotypes of the mutans streptococci responsible for dental caries. They also suggest the existence of more serological varieties among mutans species.

Antibodies, Bacterial↗
PubMed2006

Human beta-defensin-3: a promising antimicrobial peptide.

The field of naturally occurring antimicrobial peptides is a research area rapidly expanding due to the high potential of such molecules as new antimicrobial drugs. In this regard, the human beta-defensin-3 is particularly attractive because of its strong antibacterial activity, relative salt-insensitiveness and low toxicity for host cells.

Amino Acid Sequence↗
PubMed2005

Human CD56bright and CD56dim natural killer cell subsets respond differentially to direct stimulation with Mycobacterium bovis bacillus Calmette-Guérin.

Mycobacterium bovis bacillus Calmette-Guérin (BCG) is capable of directly stimulating several effector functions of human natural killer (NK) cells in the absence of interleukin-12 and professional antigen presenting cells. To assess the contribution of two main human NK-cell subsets (CD56(dim) and CD56(bright)) to the overall in vitro NK-cell response to BCG, peripheral blood mononuclear cells depleted of nylon wool-adherent cells or purified NK cells were stimulated with live BCG. By combining intranuclear bromodeoxyuridine (BrdU) staining and analysis of CD56 marker intensity, statistically higher percentages of BrdU(+) cells were found among the CD56(bright) subset than the CD56(dim) subset after 6 days of stimulation with BCG. Similarly, evaluation of intracellular interferon-gamma (IFN-gamma) revealed that CD56(bright) cells were those mainly involved in IFN-gamma production in response to BCG. In contrast, the CD56(dim) subset contained higher levels of perforin and granzyme A, two key molecules for exocytosis-mediated cytotoxicity, than the CD56(bright) subset. Although 16-20-h stimulation with BCG did not substantially alter the expression of cytotoxic molecules by the two subsets, a decrease in perforin content was observed in the CD56(dim), but not in the CD56(bright) subset, following 4-h incubation with the NK-sensitive target K562 cell line. This decrease in perforin content correlated with the induction by BCG-stimulated NK cells, of early markers of apoptosis on target cells to a greater extent than unstimulated cells suggesting a major role for the CD56(dim) subset in cytotoxic activity in response to BCG. Taken together, these results demonstrate that CD56(bright) and CD56(dim) human NK-cell subsets exert different functional activities in response to a live bacterial pathogen.

Alleles↗
PubMed2004

An alternative and simple method to consistently prepare viable isolated human islets for clinical transplantation.

We describe a method to consistently prepare human islets for transplantation. By combining a simple collagenase digestion method and a density gradient purification system, we were able to obtain successful isolations (>/=200,000 islet equivalents, >/=50% purity) in 69% of processed glands. No reagent of animal source was used. Isolated islets were morphologically well maintained and functionally competent, with sterility confirmed in 97% of cases. Two patients were transplanted with islets prepared by this method; graft function was demonstrated for a few months. Improved simplicity and consistency, together with adequate quality of the preparations, are the main features of this isolation method.

Adult↗
PubMed2004

The risk of contracting an infectious disease from blood transfusion.

In the general population, the likelihood of an individual receiving a transfusion has been calculated to be about 0.89% per year, increasing dramatically with age. Massive intraoperative hemorrhage from trauma, cardiopulmonary bypass, and orthotopic liver transplantation need substantial replacement therapy. In renal transplantation, blood transfusion is a debated induction tool for specific allograft tolerance, since it causes a nonspecific down-regulation of immune function. In transplantations, in humoral immune deficiencies, in hematological disorders, and in HIV infection, the intravenous immunoglobulin prophylaxis may alter the monocyte/macrophage system host immunity and immune surveillance against infection, tissue or cell damage, and malignancy. Some persons, like Jehovah's Witnesses, object to transfusion of blood products, posing ethical and practical issues concerning treatment of blood disorders, transplantation, and trauma. In this review we examined the actual risk of contracting an infectious disease from an allogeneic blood transfusion to contribute to an uneasy decision-making process. We have found that the procedure is presently considerably safe.

Bacterial Infections↗
PubMed2004

Enhanced resolution of random amplified polymorphic DNA genotyping of Pseudomonas aeruginosa.

AIMS: To develop a rapid, sensitive and reproducible screening test for the detection of nosocomial spreading of Pseudomonas aeruginosa. METHODS AND RESULTS: Ps. aeruginosa genomic DNA extraction, RAPD-PCR, electrophoresis on acrylamide gel and silver staining were performed by using standardized reagents and conditions. The results were compared with the agarose gel electrophoresis followed by ethidium bromide staining. CONCLUSIONS: The coupling of acrylamide gel electrophoresis and silver staining gave about 80% more DNA bands than the traditional method, allowing a finer discrimination among different Ps. aeruginosa strains. SIGNIFICANCE AND IMPACT OF THE STUDY: By enhancing the resolution of the electrophoretic separation and the sensitivity of the staining, random amplification could be easily applied to the surveillance and prevention of nosocomial infections by clinical microbiology laboratories.

Bacterial Typing Techniques↗
PubMed2003

Increasing serum levels of IgM anti-HCV are diagnostic of recurrent hepatitis C in liver transplant patients with ALT flares.

Recurrent hepatitis and acute rejection share common features which make difficult for diagnosis in liver transplant hepatitis C virus (HCV) positive patients. We studied the usefulness of quantitative monitoring of HCV RNA and immunoglobulin (Ig)M anti-HCV in the differential diagnosis between recurrent hepatitis and acute rejection in 98 consecutive anti-HCV positive liver transplant patients. Aminotransferase levels, serum HCV RNA and IgM anti-HCV were measured at the time of transplantation and monthly thereafter. A liver biopsy (LB) was obtained when serum aminotransferase levels increased to twice or more than normal. During a mean follow-up of 16 months 86 aminotransferase flares were observed. Histology was compatible with recurrent hepatitis C in 44 cases and with acute rejection in 28, doubtful in 14. The fluctuations of HCV RNA serum levels were not significantly different in the three groups. Serum IgM anti-HCV levels increased (from negative to positive or with value variations > or = 0.18) in 36 of 44 cases with recurrent hepatitis C at the time of alanine aminotransferase (ALT) flare. IgM anti-HCV remained unchanged in all rejection cases (P < 0.001), but increased in 10 of 11 histologically doubtful cases that were diagnosed as hepatitis at the second LB. Increasing serum levels of IgM anti-HCV at the time of ALT flares are significantly associated with recurrent hepatitis C in liver transplant patients. The quantitative monitoring of IgM anti-HCV appears to be an additional diagnostic tool for distinguishing recurrent hepatitis C from acute graft rejection with a 100% specificity; 100% positive predictive value and 88.9% diagnostic accuracy.

Adult↗
PubMed2002

Purification, biochemical characterization and immunogenicity of SA5K, a secretion antigen of Mycobacterium tuberculosis.

Mycobacterium tuberculosis (MTB) secretory proteins are generally considered important antigens for immune protection against tuberculosis (TB). An 8.3-kDa secretory antigen of MTB and Mycobacterium bovis bacillus Calmette-Guérin (BCG), called SA5K, was recently identified and cloned in our laboratory. In this report, recombinant SA5K containing a histidine hexamer was expressed in Escherichia coli and purified to investigate its biochemical structure and to establish whether it was immunogenic for healthy sensitized and nonsensitized human donors and for patients infected with MTB. The protein nucleotide sequence was shown to be identical in BCG and in MTB. SA5K revealed an abnormal electrophoretic mobility in SDS-PAGE that made it look lighter than it is in Western blotting. While recombinant SA5K was poorly recognized by T lymphocytes from patients with pulmonary TB, it elicited proliferation of CD4+ T lymphocytes in the vast majority of healthy individuals sensitized to mycobacterial antigens by BCG vaccination. At a serum dilution of 1 : 80, antibodies reacting against recombinant SA5K were found in 67% of sera from TB patients and in 73% of sera from healthy subjects. The percentage of positive subjects dropped at higher serum dilutions, but no significant difference in the recognition rate was observed between TB patients and healthy donors and between healthy vaccinated and nonvaccinated subjects. Owing to the high percentage of sera from healthy subjects who recognized SA5K in Western blotting, the antigen seems to exhibit, at least in the present form, a poor specificity for an employment for a serodiagnosis of TB.

Antigens, Bacterial↗
PubMed2002

Identification, molecular cloning, and evaluation of potential use of isocitrate dehydrogenase II of Mycobacterium bovis BCG in serodiagnosis of tuberculosis.

Diagnosis of tuberculosis is time-consuming and requires infrastructures which are often not available in countries with high incidences of the disease. In the present study, an 82-kDa protein antigen was isolated by affinity chromatography and was identified by peptide mass fingerprinting as isocitrate dehydrogenase II, which is encoded by the icd2 gene of Mycobacterium bovis BCG. The icd2 gene of BCG was cloned by PCR, and the product of recombinant gene expression was purified and analyzed by two-dimensional polyacrylamide gel electrophoresis. The recombinant protein, named rICD2, was tested for its recognition by immunoglobulin G (IgG) antibodies from the sera of 16 patients with tuberculosis (TB) and 23 healthy individuals by Western blotting. The results showed that rICD2 is recognized by IgG antibodies from the sera of all TB patients tested at serum dilutions of > or = 1:640. At a serum dilution of 1:1,280, the sensitivity was 50% and the specificity was 86.9%. These results indicate that rICD2 might represent a candidate for use in a new assay for the serodiagnosis of TB.

Adult↗
PubMed2001

Involvement of the Mycobacterium tuberculosis secreted antigen SA-5K in intracellular survival of recombinant Mycobacterium smegmatis.

A new protein (SA-5K) secreted in culture filtrates by Mycobacterium bovis, Mycobacterium tuberculosis, and few other mycobacterial species was previously identified and purified in our laboratory. In order to evaluate the putative role of SA-5K during intracellular mycobacterial growth, in the present study the SA-5K gene was cloned and expressed in Mycobacterium smegmatis, a rapid growing non-pathogenic mycobacterium which does not contain the gene for the protein. SA-5K expression in the THP-1 human macrophage cell line infected with the recombinant strain (M. smegmatis-pROL5K) was demonstrated by RT-PCR on RNA extracted from bacterial cells following 24 and 48 h of infection. Intracellular SA5K expression was associated with a higher cfu increase of M. smegmatis-pROL5K in comparison to the negative control strain (M. smegmatis recombinant for the cloning vector) (P=0.01). No significant change in SA-5K synthesis by M. smegmatis-pROL5K was observed when the recombinant strain was grown in vitro in different stress conditions such as iron deprivation, pH 4.5, presence of nitric oxide or hydrogen peroxide. The results presented in this study suggest a possible role for SA-5K in intracellular survival of recombinant M. smegmatis, though the function of the protein remains unknown.

Antigens, Bacterial↗
PubMed2001

Molecular monitoring of Candida albicans infections in liver transplant recipients.

This report describes the use of the 27A probe for the molecular monitoring of Candida albicans infections in liver transplant recipients. Nosocomial candidiasis is the major fungal infection in liver transplant recipients, with Candida albicans being the species most frequently isolated. The molecular epidemiology of Candida albicans infections has been widely investigated, but scant attention has been focused on monitoring the identity of infecting strains in individual patients over the entire course of their hospitalization. In the study presented here, a total of 179 Candida albicans isolates were collected from 10 liver transplant recipients during multiple surveillance cultures performed before and after liver transplantation and from three healthcare workers at the Transplant Unit of Ospedale di Cisanello, Pisa (Italy). Computer-aided analysis of the 27A-probed DNA fingerprints, used to compare the genetic relatedness of all the Candida albicans isolates, showed that most of the patients colonized with Candida albicans before transplantation harbored a unique Candida albicans genotype. This genotype persisted over the entire course of hospitalization and caused multiorgan failure in two patients, both of whom died from endogenously borne Candida albicans infections. Nosocomial acquisition of Candida albicans strains could be monitored in a timely manner in the other patients; for some of them, subsequent strain replacement was registered at different body sites during the post-transplant period. Neither cross-infection between patients nor transmission from healthcare workers to patients occurred in this hospital setting. These results indicate that the molecular monitoring of Candida albicans strains isolated from liver transplant recipients during their hospitalization may provide timely information about the identity of individual Candida albicans strains causing infections.

Adult↗
PubMed2001

Effect of removable orthodontic appliances on oral colonisation by mutans streptococci in children.

Little is known about the effect of removable orthodontic appliances on oral colonisation by mutans streptococci (MS). In the present study, the frequency of isolation and serotype distribution of MS were evaluated in two groups of children, one undergoing therapy with removable appliances and the other not subjected to any kind of orthodontic treatment, respectively. Streptococci isolated from dental plaque samples from both groups of children were identified as mutans streptococci on the basis of their morphological and biochemical properties and were then serotyped in an enzyme immuno-assay using monoclonal antibodies. The number of subjects harbouring MS in their dental plaque was statistically higher in the group of orthodontic children without caries experience (CF) in comparison with CF children of the control group (10/12, 83.3% vs. 15/44, 34%). No clear difference was observed in the distribution of the different MS serotypes between the experimental and control group: S. mutans c,f serotype was the most frequently isolated in both groups of children followed by S. mutans serotype e and S. sobrinus serotype g. Such results suggest that the use of removable appliances may lead to the creation of new retentive areas and surfaces, which favour the local adherence and growth of MS. The data obtained stress the importance of a careful monitoring of patients treated orthodontically for risk of caries development.

Case-Control Studies↗
PubMed2001

Use of a recombinant strain of Mycobacterium avium expressing beta-galactosidase to evaluate the activities of antimycobacterial agents inside macrophages.

A reliable and low-cost method that enables rapid screening of the activity exerted by new antimicrobial agents on intracellularly growing Mycobacterium avium has been developed. To this aim, a recombinant (lacZ) strain of M. avium expressing the Escherichia coli beta-galactosidase gene was used to evaluate, in murine macrophages, the susceptibility of M. avium to common antimycobacterial agents. beta-Galactosidase levels, measured in the presence of each of the antibiotics tested, were closely correlated with the number of CFU recovered from the M. avium lacZ strain-infected macrophages.

Animals↗
PubMed2001

Interaction between piroxicam and azithromycin during distribution to human periodontal tissues.

BACKGROUND: Non-steroidal anti-inflammatory drugs and antibiotics are important in the prevention of infections and pain associated with periodontal surgery as well as in the adjunctive therapy of periodontal disease. In this study, patients undergoing oral surgery were treated with piroxicam and azithromycin to examine the interactions of these drugs on periodontal tissues. METHODS: Sixty-six patients were assigned to 3 groups and treated for 3 days as follows: 1) piroxicam 20 mg/day; 2) azithromycin 500 mg/day; or 3) piroxicam 20 mg/day plus azithromycin 500 mg/day. Samples of blood, saliva, gingiva, and alveolar bone were collected during surgery and at days 0.5, 2.5, 4.5, and 6.5 after last dose. Piroxicam concentrations were assayed by high-performance liquid chromatography and azithromycin concentrations by microbiological assay. RESULTS: In patients treated with piroxicam alone, the highest drug concentrations were found in plasma at each time point, but consistent piroxicam levels were also detected in gingival samples up to 4.5 days. The combined treatment with piroxicam plus azithromycin was associated with a reduction of piroxicam concentrations in periodontal tissues. In patients receiving azithromycin alone, high drug levels were measured in periodontal tissues up to 6.5 days. This distribution pattern did not vary in patients treated with piroxicam plus azithromycin. CONCLUSIONS: Treatment with piroxicam or azithromycin alone ensures a favorable distribution of these drugs into periodontal tissues. However, upon combined administration, azithromycin interferes negatively with the periodontal disposition of piroxicam. This interaction might depend on the displacement of piroxicam from acceptor sites at the level of periodontal tissues.

Adolescent↗
PubMed2000

Identification of distinct lymphocyte subsets responding to subcellular fractions of Mycobacterium bovis bacille calmette-Guérin (BCG).

In order to investigate the ability of Mycobacterium bovis BCG vaccination to induce immune responses toward different classes of mycobacterial antigens and the cell populations involved in such responses, proliferation of distinct human lymphocyte subsets from BCG-vaccinated donors in response to different subcellular fractions of BCG was analysed and compared with that of not sensitized subjects. Proliferation of different cell subsets was evaluated by flow cytometric determination of bromodeoxyuridine incorporated into DNA of dividing cells and simultaneous identification of cell surface markers. Although a certain degree of variability was observed among different donors, after 6 days of in vitro stimulation BCG-vaccinated subjects displayed, as a mean, a stronger blastogenic response to all the classes of antigens compared with non-sensitized ones. PPD, culture filtrates and membrane antigens induced a predominant proliferation of CD4+ T cells. In contrast, preparations enriched in cytosolic antigens elicited strong proliferation of gammadelta+ T cells which, as a mean, represented 55% of the proliferating cells. Although to a lesser extent, proliferation of gammadelta+ T cells was also elicited by preparations enriched in membrane and cell wall antigens. In response to the latter preparation proliferation of CD4+ T cells and CD16+/CD3- (natural killer (NK)) cells was observed, as well. In particular, cell wall antigens were found to induce significantly higher levels of proliferation of NK cells compared with all the other classes of antigens.

Adult↗
PubMed2000

Effect of a novel mucoadhesive polysaccharide obtained from tamarind seeds on the intraocular penetration of gentamicin and ofloxacin in rabbits.

This report describes the efficacy of a novel mucoadhesive polymer, the tamarind seed polysaccharide, as a delivery system for the ocular administration of hydrophilic and hydrophobic antibiotics. Healthy rabbits were subjected to repeated ocular instillations with either conventional gentamicin or ofloxacin or these agents viscosified with the tamarind seed polysaccharide. Administration of viscosified preparations produced antibiotic concentrations both in the aqueous humour and cornea that were significantly higher than those achieved with the drugs alone. The increased drug absorption and the prolonged drug elimination phase obtained with the viscosified formulations indicate the usefulness of the tamarind seed polysaccharide as an ophthalmic delivery system for topical administration of antibiotics.

Administration, Topical↗