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Biomedical subjects

S Lombardi

Publications and source records attributed to S Lombardi.

At least 19 recordsLinked to original sources
PubMed1995

Renal involvement in feline immunodeficiency virus infection: p24 antigen detection, virus isolation and PCR analysis.

Renal alterations characterized morphologically by glomerular and tubulo-interstitial lesions and clinically by a heavy proteinuria and sometimes by renal failure are frequent in feline immunodeficiency virus (FIV) infected cats. To investigate the possible role of local FIV replication in the genesis of this renal damage, renal tissues of 15 consecutive naturally infected and five non-infected cats were examined for traces of the virus by immunohistochemistry, using a monoclonal anti-p24 antibody in a streptavidin-biotin peroxidase labeled system, cultivation and polymerase chain reaction (PCR). Tubular epithelial cells as well as scattered interstitial inflammatory and glomerular cells were positive for p24 antigen in 13 cats. Viral isolation was successful in seven cats, and FIV gag DNA and RNA sequences were detected in 14 and five cats, respectively. Control cats were constantly negative. Although not conclusive, these results suggest that a direct role of FIV in the induction of the renal damage observed in infected animals is possible.

Animals↗
PubMed1995

Epitope mapping of the V3 domain of feline immunodeficiency virus envelope glycoprotein by monoclonal antibodies.

A panel of six IgG monoclonal antibodies (MAbs) was produced by immunizing mice with a 22 amino acid synthetic peptide, designated V3.3, of the third variable region of feline immunodeficiency virus (FIV) envelope glycoprotein. This peptide is known to induce neutralizing antibodies in cats. In ELISA all MAbs reacted with purified SDS-disrupted FIV and in flow cytometry all MAbs stained permeated, persistently infected FL4 cells but not unfixed FL4 cells; this indicated that the MAbs recognize essentially cryptic epitopes of the gp100 V3 loop. By direct ELISA using partially overlapping synthetic peptides and by competition binding studies, the anti-V3.3 MAbs were shown to detect at least four distinct epitopes, two located in the amino-terminal half and two in the carboxy-terminal half of the sequence. When tested for neutralizing activity by the syncytium inhibition assay in Crandell feline kidney cells, all anti-V3.3 MAbs neutralized FIV at high dilution. However, at low dilution two MAbs exhibited much less neutralizing activity. These results indicate that the V3 region of FIV contains multiple epitopes involved in neutralization.

Amino Acid Sequence↗
PubMed1995

Circulating immune complexes and analysis of renal immune deposits in feline immunodeficiency virus-infected cats.

Total immunoglobulin content and concentration of immune complexes (IC) were determined in the sera of 51 cats infected with feline immunodeficiency virus (FIV) and of 40 controls. IgG and IgM were quantified by radial immunodiffusion and circulating IC (CIC) by the CIC-conglutinin assay. IgG fractions were obtained by acid elution from kidney tissues of 15 FIV-infected and five negative control cats to investigate the possible role of IC in the genesis of renal damage observed in infected animals. Mean concentrations of IgG and circulating IC were higher in FIV-infected cats than in controls (29.6 +/- 6.7 versus 23.0 +/- 1.9 mg/dl (mean +/- s.d.) P < 0.001; and 66.5 +/- 17.0 versus 27.4 +/- 19.9% I, P < 0.001, respectively), while IgM levels were only slightly increased (0.9 +/- 0.05 versus 0.87 +/- 0.04 mg/dl, P < 0.02). Immunoglobulin fractions were eluted from 10 of the 15 renal tissue samples from FIV-infected cats and were found to be polyclonal and at least partly specific for FIV antigens. These findings confirm the presence of a B cell activation in FIV-infected cats and demonstrate the presence of high levels of CIC in their sera. The presence of immune deposits in renal tissues suggests that IC might play a role in the pathogenesis of the renal damage observed in FIV-infected cats.

AIDS-Associated Nephropathy↗
PubMed1995

The fluctuations of hepatitis C virus RNA and IgM anti-HCV (core) serum levels correlate with those of alanine aminotransferases during the hepatitis relapses of patients treated with interferon.

Variations in the serum levels of hepatitis C virus (HCV) RNA. IgM antibody against the HCV 'core' structural protein (c22) and alanine amino-transferase (ALT) were measured in 23 patients with chronic hepatitis C who underwent therapy with interferon-alpha 2a (IFN alpha 2a). Low pretreatment levels of viraemia and undetectable IgM anti-core were significantly associated with a long-term response to treatment. In patients with hepatitis relapses after the end of treatment, HCV RNA levels increased before or at the same time as ALT in 29 out of 34 cases (85%). ALT flares occurred before or simultaneously with IgM anti-core elevations in 18 out of 20 cases (90%). Therefore, post-treatment hepatitis C exacerbations show the same sequence of events seen as in hepatitis B exacerbations (increases of viraemia followed by those of ALT and IgM anti-'core'). These findings underscore the diagnostic and prognostic usefulness of monitoring anti-HCV-positive patients with quantitative assays for HCV markers.

Alanine Transaminase↗
PubMed1995

Examination of variables affecting syncytium formation by, and serum neutralization of, feline immunodeficiency virus on CrFK cells.

The feline immunodeficiency virus (FIV) induces syncytia in Crandell feline kidney (CrFK) cells grown in low fetal bovine serum-containing medium. This finding has allowed the development of sensitive FIV titration and neutralization assays using syncytium formation as an indicator of infection. In this report we examine several variables that can influence number and size of syncytia. In addition, by performing assays under rigidly controlled culture conditions, we confirm that serum neutralization assays based on FIV-induced syncytium formation in CrFK cells detect broadly reactive neutralizing antibodies.

Animals↗
PubMed1994

Detection of feline immunodeficiency virus p24 antigen and p24-specific antibodies by monoclonal antibody-based assays.

A panel of monoclonal antibodies (mAbs) detecting distinct B-cell epitopes on p24 core viral protein of feline immunodeficiency virus (FIV) were employed to develop immunoassays to measure p24 concentration in culture and serum samples, to localize p24 in FIV-infected cells and tissues, and to detect anti-p24 antibodies in cat sera. In its optimized configuration the p24 capture assay detected as little as 0.25 ng/ml of protein. The assay was found at least as sensitive as the reverse transcriptase activity assay in FIV-infected lymphocyte cultures and proved capable of detecting p24 antigen in acid pretreated sera from a high proportion of FIV-infected cats. The mAbs were also successfully used to detect the p24 antigen in permeated FIV-infected cells by flow cytometry and in tissue sections from FIV-infected cats by immunohistochemical staining. Anti-p24 antibodies in FIV-infected cat sera were assayed by a competitive capture ELISA which readily identified occasional false positive results provided by a standard ELISA using purified whole FIV-coated wells.

Animals↗
PubMed1993

Detection of B epitopes on the p24 gag protein of feline immunodeficiency virus by monoclonal antibodies.

Seven monoclonal antibodies were obtained after immunization of mice with purified sodium dodecyl sulfate (SDS)-disrupted feline immunodeficiency virus (FIV). Six antibodies specifically bound antigens in the cytoplasm of FIV-infected cells as determined by indirect immunofluorescence and reacted with FIV p24 gag gene product in immunoblots. One reacted positively with virus-infected cells, but failed to recognize FIV structural proteins by immunoblotting. Using competition binding studies, the anti-p24 monoclonals were shown to detect four distinct B-cell epitopes. Competition with sera of FIV-infected cats showed that such epitopes are immunogenic also in the natural host species.

Animals↗
PubMed1992

In vitro immune recognition of synthetic peptides from the Plasmodium falciparum CS protein by individuals naturally exposed to different sporozoite challenge.

The impact of duration and intensity of sporozoite challenge on the in vitro cell immune response to synthetic peptides of the circumsporozoite (CS) protein of Plasmodium falciparum was investigated in residents of a malaria endemic area in Burkina Faso (West Africa). Lymphocyte proliferation and interferon-gamma (IFN-gamma) production were used to assess immune recognition of synthetic peptides corresponding to the polymorphic Th2R and Th3R regions, to the conserved CS.T3 sequence and to NANP and degenerate NVDP repeats. Immune responses were measured in adults and children from a village where they received more than 100 sporozoite inoculations per year and in adults living in a town, exposed to a 10-100 times lower challenge. A lifetime intense exposure apparently increased the ability to proliferate in response to most peptides in the rural adults, who all produced antibodies to NANP repeats. Surprisingly, cell cultures from these subjects seldom contained appreciable levels of IFN-gamma. In the urban adults, possibly due to the moderate challenge they are exposed to, significant differences in the proliferative potentials of the peptides could be detected. The highest stimulation indices were obtained with the genetically unrestricted CS.T3 peptide. Remarkably, proliferative responses to Th2R and Th3R appeared to be correlated with the humoral response to the CS protein, indicating a T helper significance of the epitopes. The differing proliferative potential of the polymorphic epitopes in the urban adults suggests that polymorphism might delay the development of immune responsiveness under conditions of sporadic transmission. The children from the highly malarious village displayed the lowest proliferative scores, accompanied by a high prevalence of antibodies to NANP repeats. On the basis of these findings, the hypothesis is proposed that a pure B cell reactivity to NANP repeats could ontogenetically precede the mounting of a conventional T-B cooperative immune response.

Adult↗
PubMed1991

Waiting for the vaccine: sporozoite vaccine research entails important progress in malaria epidemiology.

The research efforts aimed at developing a vaccine against malaria, although failing thus far in their main objective, have produced molecular tools of great utility for epidemiological studies. For example, monoclonal antibodies directed against the repeats of Plasmodium circumsporozoite (CS) protein allowed the 2-site assay for detecting sporozoites in mosquitoes to be established. This immunoassay is advantageous compared with the conventional method of salivary gland dissection and microscopic examination, for it makes the identification of the sporozoite species possible, thanks to species-specific aminoacid sequences of the CS repeats. Other examples of vaccine research-derived tools are synthetic peptides reproducing the repetitive part of the CS protein, which allow antibodies to sporozoites, in individuals exposed to malaria, to be detected. Antibodies to the CS repeats of Plasmodium (Laverania) falciparum proved to be a reliable indicator of the intensity of malaria transmission and, therefore, were suitable for monitoring the impact of malaria control programmes. Finally, a project is outlined that, relying on the application of these tools, will aim at characterizing the transmission of Plasmodium (Plasmodium) malariae and at unveiling the possible relationship among different species thriving in the same distribution area, an issue which may become of relevance in view of the likely introduction of a vaccine directed against a single species.

Animals↗
PubMed1991

Indices of sustained aerobic power in young middle distance runners.

Sixteen young endurance athletes underwent physiological testing to determine their maximal oxygen uptake (VO2max), lactate threshold (lacAT), ventilatory threshold, and the slope variation point (SVP) of the linear relationship between running speed (RS) and heart rate (HR) both on the treadmill and during a field test, and the onset of blood lactate accumulation point. The RS, HR, VO2, and blood lactate concentration at which the different thresholds occurred were highly correlated, with r ranging from 0.82 to 0.90. The highest correlation was shown by RS at lacAT and RS at SVP during the field test. Various indices of sustained aerobic power in athletic children examined were shown to occur at a percentage of their VO2max similar to adult endurance runners. The tests developed for older athletes can be used in this age group as well.

Adolescent↗
PubMed1990

[Indications and surgical tactics in ulcerative rectocolitis. Our experience].

Surgical indications in URC are examined in relation to various situations of election, emergency and urgency. The various possible surgical procedures are analysed, stress being laid on criteria of choice which take account of the seriousness of the disease and of the different technical solutions now available. A series of 30 operations in 145 cases of URC is presented and complications examined in relation to the type of operation performed and to the indications. Stress is laid on the importance of intervening adequately so as to achieve the best prognostic results.

Adolescent↗
PubMed1990

Evaluation of an ELISA kit for epidemiological detection of antibodies to Plasmodium falciparum sporozoites in human sera and bloodspot eluates.

Antibodies to Plasmodium falciparum sporozoites represent a serological transmission indicator, which can be applied in epidemiological studies to estimate the intensity of malaria transmission. An ELISA method has been developed as an industrial kit to detect these antibodies, using a chemically synthesized (NANP)40 peptide as antigen. The results obtained with this kit are compared in the present paper with those obtained by an ELISA test already applied in epidemiological studies. In testing sera from individuals living in endemic areas, a high diagnostic concordance (92.1%) was obtained between the two assays. The absorbances of these sera correlated well, as shown by a correlation coefficient r = 0.877. Sera from individuals never exposed to malaria gave very low absorbances with the kit. This minimum non-specific binding increases the probability of comparable results in different studies. When the two ELISAs were evaluated for analytical sensitivity and precision, similar satisfactory results were achieved. The test can be performed not only with sera but also with eluates from filterpaper bloodspots. Modifications of the kit to reduce its cost and suggestions regarding distribution and funding are also proposed.

Animals↗
PubMed1990

Intraerythrocytic administration of a synthetic Plasmodium antigen elicits antibody response in mice, without carrier molecules or adjuvants.

The synthetic peptide (NANP)40, reproducing the tandem-repeated epitope of the circumsporozoite protein of Plasmodium (Laverania) falciparum, was entrapped into murine, autologous erythrocytes by a hypotonic dialysis method. Mice immunized intravenously with minute amounts of encapsulated peptide produced considerable antibody titres. This result indicates that intraerythrocytic antigen administration may have a potential as an immunization system for humans, since it dispenses with adjuvants and carrier molecules.

Animals↗
PubMed1990

The in vitro adherence of murine eosinophils, neutrophils and non-induced and induced macrophages to infective larvae of Toxocara canis (Nematoda, Ascarididae).

Infective larvae of the parasite nematode Toxocara canis were incubated in vitro with murine eosinophils, neutrophils and non-induced and induced macrophages. The interactions between the different types of cells and the worms were observed in the presence or absence of immune mouse serum and/or complement. Cells showed considerable differences in the manner, duration and outcome of this interaction. Despite the adhesion of cells to the larvae of T. canis, there was no evidence of damage to the worms. Scanning and transmission electron microscopic observations suggest that the cells adhere to the cuticular surface via an electron-dense material. This material might play a protective role against the helmintotoxic capacity of the inflammatory cells.

Animals↗
PubMed1990

Our experience in the management of pancreatic pseudocysts.

The authors discuss the problems in the diagnosis and treatment of pancreatic pseudocysts; they emphasize the risk of complication. The authors discuss their personal experience in the treatment of 31 pancreatic pseudocysts using the different techniques, and the very good results they observed in their own series.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed1989

Immunotechniques for epidemiology of malaria: appropriate tools for integration of primary health care with malaria research and control.

Community-based malaria control with integrated primary health care appears to be the most feasible approach for endemic countries in their struggle against malaria. To plan and implement personal protection and vector control measures, there is the need for comprehensive information about local modes of transmission. Experience with insecticide-based vector control programmes and entomological data accumulated over the years has revealed vector systems of extraordinary heterogeneity, creating multifaceted transmission situations. The primary health care-system offers an appropriate structure to collect and evaluate microepidemiological information countrywide. Community and health workers trained and supervised by qualified personnel could be involved in the assessment of clinical, parasitological and entomological indices. Community participation is facilitated if personnel are taught the use of immunotechniques. Tests can be performed on dried material which allows samples to be stored for months without refrigeration, so that transport to and processing in a central laboratory are not subject to time constraints. This paper describes and discusses enzyme-linked immunosorbent assays to determine if antibodies to sporozoites are present in blood collected as dried spots and to identify the origin of bloodmeals using dried mosquito abdomens.

Animals↗
PubMed1989

Development of the human immune response against the major surface protein (gp190) of Plasmodium falciparum.

The 190-kilodalton glycoprotein (gp190) of Plasmodium falciparum, the precursor of the major surface proteins of merozoites, is considered a promising candidate for a blood stage malaria vaccine. DNA sequences specific for the gp190 of the two isolates K1 and MAD20 were subcloned and expressed in Escherichia coli. The panel of fusion proteins obtained represents about 80% of the polymorphic sequences observed so far within various isolates of P. falciparum. Sera from individuals living in a malaria-endemic area of West Africa were tested in immunoblots against the gp190 fusion proteins, and antibody reactivity was mapped to defined regions of the gp190. Depending on the age of the individual and on the presence of parasites in the blood, distinct regions of gp190 were differentially recognized by the respective antibodies. Similarly, the analysis of sera from German patients with acute malaria revealed a distinct pattern. When grouped according to age and to parasitemia, the reactivity of the sera of people living in malaria-endemic areas may indicate a correlation between certain gp190 regions and protective immune response.

Animals↗