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Biomedical subjects

M Alessio

Publications and source records attributed to M Alessio.

At least 37 records · Page 2Linked to original sources
PubMed1996

Altered body water distribution in subjects with juvenile rheumatoid arthritis and its effects on the measurement of water compartments from bioelectric impedance.

OBJECTIVE: To assess the reliability of bioelectric impedance analysis (BIA) for predicting total body water (TBW) and extracellular water (ECW) in children affected by juvenile rheumatoid arthritis (JRA). SUBJECTS: Thirty-nine children affected by JRA and 23 healthy children of similar age (11.0 +/- 3.6, range 3.0-19.0 y) were recruited for the study. METHODS: TBW and ECW were measured by deuterium oxide and bromide dilution, respectively. Bioelectric impedance (Z) was measured at frequencies of 5, 50 and 100 kHz. The prediction of TBW and ECW from BIA was based on the impedance index (ZI = height2/Z, cm2/omega). RESULTS: TBW standardized per kg of body weight and ECW standardized per litre of TBW were significantly higher in JRA as compared to control patients (59.7 +/- 2.4 vs 57.7 +/- 2.7% and 44.5 +/- 4.6 vs 38.1 +/- 7.9%, with P < 0.005 and P < 0.0001, respectively). Moreover, intracellular water standardized per litre of TBW was significantly lower in JRA than in control subjects (55.5 +/- 4.6 vs 62.5 +/- 8.1, with P < 0.0001). In both controls and patients, the use of ZI at 5kHz offered the more accurate prediction of ECW. However, the use of ZI at 100 kHz did not offer a better prediction of TBW as compared to its value of 50 kHz. Control-generated formulae for predicting water compartments from BIA [TBW = 0.716 x ZI at 100 kHz-1.504, r = 0.934, s.e.e. = 2.2 l;:ECW = 0.430 x ZI5-3.652, r = 0.869(7) s.e.e. = 1.7 l] underestimated TBW and ECW in JRA patients. However, population-specific formulae [TBW (1) = 0.766 x ZI at 100 kHz-0.053, r = 0.939, s.e.e. = 2.8 l; ECW (l) = 0.399 x ZI at 5 kHz-0.283, r = 0.886, s.e.e. = 1.7 l] allowed an accurate prediction of TBW and ECW in JRA patients, taking into account their altered body water distribution. CONCLUSIONS: Altered water distribution impedes the use of formulae developed on healthy children to predict TBW and ECW from BIA and JRA patients. It is hypothesized that chronic inflammation and subclinical malnutrition may be responsible for the altered body water distribution of JRA patients. Traditional body composition models may require adjustments for use in JRA children due to their altered body hydration and water distribution.

Adolescent↗
PubMed1995

Middle T antigen-transformed endothelial cells exhibit an increased activity of nitric oxide synthase.

Endothelioma cell lines transformed by polyoma virus middle T antigen (mTa) cause cavernous hemangiomas in syngeneic mice by recruitment of host cells. The production of nitric oxide (NO), as measured by nitrite and citrulline production, was significantly higher in mTa-transformed endothelial cells in comparison with nontransformed control cells. The maximal activity of NO synthase (NOS) was about 200-fold higher in cell lysates from the tEnd.1 endothelioma cell line than in lysates from nontransformed controls, whereas the affinity for arginine did not differ. The biochemical characterization of NOS and the study of mRNA transcripts indicate that tEnd.1 cells express both the inducible and the constitutive isoforms. NOS hyperactivity is not a simple consequence of cell transformation but needs a tissue-specific mTa expression. Since tEnd.1-conditioned medium induces NOS activity in normal endothelial cells, most likely NOS hyperactivity in endothelioma cells is attributable to the release of a soluble factor. This NOS-activating factor, which seems to be an anionic protein, could stimulate tEnd.1 cells to express NOS by an autocrine way. By the same mechanism, tEnd.1 cells could induce NOS in the neighboring endothelial cells, and NO release could play a role in the hemangioma development. Such hypothesis is confirmed by our in vivo experiments, showing that the administration of the NOS inhibitor L-canavanine to endothelioma-bearing mice significantly reduced both the volume and the relapse time of the tumor.

Amino Acid Oxidoreductases↗
PubMed1995

Nutritional status in active juvenile chronic arthritis not treated with steroids.

Nutritional status and nutrient intake were assessed in 17 children with active juvenile chronic arthritis (JCA) who never received steroids and in 17 controls matched for age and sex. Five patients had systemic, seven polyarticular and five oligoarticular JCA. Values significantly below those of the controls were found in systemic patients for height (p<0.05), upper arm circumference (p<0.05) and arm muscle area (p<0.01), and in polyarticular subjects for arm muscle area (p<0.01). All patients had unremarkable anthropometric fat measurements. All anthropometric measurements were normal in oligoarticular patients. Twelve JCA patients had reduced serum iron (Fe), 6 reduced serum zinc (SZn), 14 reduced intra-erythrocytic zinc (EZn) and 2 reduced serum copper (SCu). SZn was inversely correlated with erythrocyte sedimentation rate (ESR) (p=0.023). EZn was inversely related to lymphocyte count (p=0.022). SCu was related to ESR (p=0.037) and to lymphocyte count (p=0.016). No significant difference in nutrient intake was found between patients and controls. Active JCA was associated with reduced muscular mass, Fe, SZn, EZn. These alterations did not depend on reduced nutrient intake.

Adolescent↗
PubMed1995

Reduced bone mineral content and normal serum osteocalcin in non-steroid-treated patients with juvenile rheumatoid arthritis.

OBJECTIVES: To distinguish the effects of juvenile rheumatoid arthritis (JRA) on bone mineralisation from those possibly caused by steroid therapy. METHODS: Bone mineral status was evaluated in 20 children (five boys and 15 girls) with active JRA who never received steroids. Seven had oligoarticular, nine had polyarticular, and four had systemic JRA. Bone mineral content (BMC) was assessed by single beam photon absorptiometry and expressed as a Z score relative to normal values in healthy children. Serum calcium, phosphate, and alkaline phosphatase were measured by colorimetric methods. Whole parathyroid hormone was assayed by Immuno Radiometric Assay. Serum osteocalcin was measured by specific radioimmunoassay. Nutrient intake was assessed by a 24 hours dietary recall. BMC and nutrient intake were also assessed in an age and sex matched control group. RESULTS: BMC was -1.5 (SEM 0.8) Z scores in patients and 0.4 (0.3) in the control group (p = 0.02). BMC averaged -4.9 (2) Z scores in the systemic JRA group, -1 (0.6) in the polyarticular group and 0.3 (0.7) in oligoarticular JRA patients. Serum calcium, phosphate and osteocalcin values were normal in all patients. No significant difference was found between JRA patients and controls in calcium, phosphate, energy, and protein intake. CONCLUSION: JRA subjects have significantly reduced BMC even in the absence of any steroid therapy. Bone demineralisation appears to depend more on disease activity and on reduced motility than on reduced nutrient intake.

Adolescent↗
PubMed1993

Platelet activation and inhibition of malarial cytoadherence by the anti-CD36 IgM monoclonal antibody NL07.

The surface glycoprotein CD36 (GPIV) is known to mediate the adhesion of Plasmodium falciparum malaria-infected red blood cells and to be a receptor for extracellular matrix proteins such as collagen and thrombospondin. The murine monoclonal IgM antibody NL07, which is specific for CD36, has now been shown to also be a potent inhibitor of the adhesion of P falciparum malaria-infected red blood cells to C32 melanoma cells. Treatment of platelets with NL07 monoclonal antibody resulted in rapid degranulation, release of ATP and serotonin, increase in [Ca2+]i, and tyrosine phosphorylation of a substrate protein of 130 kD. In about one-half of the experiments, activation with NL07 resulted in the formation of small aggregates of 10 to 30 platelets, whereas in the other half of the experiments, large aggregates were seen similar to those induced by adenosine diphosphate (ADP) and these large aggregates could be converted to the small aggregates by ATP alpha S or by AP-2 or other antibodies against GPIIb and/or IIIa. Microaggregates of 2 to 5 platelets were seen with Glanzmann's platelets that constitutively lack GPIIb/IIIa. Aggregate formation was not seen with heat-treated serum, in the presence of anti C1q antibodies, or when using C5-, C8-, or C9-deficient human sera. Although activation of platelets with purified complement components results in a slow morphologic change without aggregation, involvement of CD36 results in rapid complement-mediated activation leading to formation of small aggregates that is largely independent of GPIIb/IIIa and that, under certain circumstances, proceeds to the formation of large ADP-dependent aggregates.

Adenosine Diphosphate↗
PubMed1993

Interspecific plasmid transfer and modification of heat-stable enterotoxin expression by Klebsiella pneumoniae from infants with diarrhea.

We have previously described two heat-stable enterotoxins (ST) produced by Citrobacter freundii and by Klebsiella pneumoniae. To see whether transfer of toxigenic ability may occur between different bacterial species, conjugal mating experiments were performed using strains isolated from children. Donors and recipients were incubated together. ST production by the recipients was tested by the suckling mouse assay, which is the standard biologic method for detecting ST, and also by an ELISA test. The latter is based on MAb directed to Escherichia coli 18- or 19-amino acid toxin. Citrobacter and E. coli strains producing an ELISA-positive ST were used as plasmid donors. Recipients were E. coli, Klebsiella P89, and Klebsiella AL55. The latter had been previously shown to be capable of producing an ELISA-negative ST, but had spontaneously lost this ability. After conjugation, all strains gave positive results in the suckling mouse assay. However, E. coli and Klebsiella P89 ST were positive in the ELISA test, whereas Klebsiella AL55 ST was negative. The same three strains were transformed by inserting the plasmid pSLM004 encoding an ELISA-positive ST. Klebsiella P89 and E. coli became capable of producing an ELISA-positive ST, whereas Klebsiella AL55 cells were positive in the suckling mouse assay but negative in the ELISA. To assess whether the toxigenicity acquired was itself transmissible, the new ST-producing strains were incubated with a nontoxigenic Citrobacter strain. The latter became capable of producing an ELISA-positive ST in all cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Toxins↗
PubMed1992

CD38: a multi-lineage cell activation molecule with a split personality.

This review reports the characteristics of the human surface molecule CD38, a structure not linked to a definite line and predominantly expressed in early and activated phenotypes. The CD38 molecule consists of a single chain of 46 kDa, spanning the membrane and with the carboxyl terminus located in the extracellular compartment. The CD38 molecule is also involved in the transduction of activation and proliferation signals, which are line unrestricted. The gene coding for the CD38 antigen has been cloned and used for the construction of simian and mouse transfectants expressing the human molecule. These cell models are used for the analysis of several unanswered issues, mainly concerning the in vivo function of CD38, the existence of a natural ligand and of polymorphism in the population.

ADP-ribosyl Cyclase↗
PubMed1991

Analysis of the human CD36 leucocyte differentiation antigen by means of the monoclonal antibody NL07.

The murine monoclonal antibody (MoAb) NL07 was generated by immunization with human platelet extracts. NL07 MoAb recognized a molecule expressed by human platelets, monocytes, and endothelial cells, as well as by the myelomonocytic line U937 and by some melanoma cells or lines. Normal endothelial cells and the melanoma cells express the NL07 epitope only while adhering to a substrate. SDS-polyacrylamide gel electrophoresis and two-dimensional gel analysis indicate that the molecule recognized by NL07 MoAb on platelets is a single chain structure featuring a molecular weight of 85 kDa under reducing conditions, with an acidic isoelectric point ranging from 5.2 to 5.5. The specific phenotype distribution and the biochemical structure indicate that NL07 MoAb recognizes the platelet GPIV (CD36) molecule, a surface glycoprotein with a functional role of thrombospondin receptor. The results of competition tests with OKM5 MoAb (specific for the CD36 molecule) confirm the molecular specificity and epitope coincidence. Furthermore, upon binding to the platelets, NL07 MoAb is able to transmit via CD36 an activation signal which is followed by a potent aggregation. On the contrary, there is lack of evidence concerning the ability of the CD36 molecule of transmitting signal(s) on the U937 cells.

Antibodies, Monoclonal↗
PubMed1990

Involvement of the multilineage CD38 molecule in a unique pathway of cell activation and proliferation.

We report clear evidence that the interaction of the CD38 molecule with the specific mAb A10 on normal human cells and lines modulates the expression of surface activation markers relevant to T, NK, and plasma cell biology and functions. Moreover A10 mAb binding is followed by proliferation effects on all the target cells analyzed, and the phenomenon is accessory cell and IL-2 dependent. The effects of A10 mAb synergizing both CD2 and CD3 activation pathways indicate that CD38 signal transduction mechanism(s) are apparently different from the aforementioned. Nevertheless the decreased A10-driven proliferation after CD3-Ti modulation suggests a possible functional interdependence between these activation pathways. Taken together, the results indicate that the CD38 molecule might play a physiologic role in T, NK, and plasma cell regulation.

ADP-ribosyl Cyclase↗
PubMed1990

CD38 molecule: structural and biochemical analysis on human T lymphocytes, thymocytes, and plasma cells.

The structure of the CD38 molecule has been evaluated by one- and two-dimensional gel analysis and by enzymatic digestions. The source of the Ag was mainly membrane preparations obtained from MLC cells, from normal thymocytes, and from the plasmocytoma line LP-1. Membranes were solubilized in NP-40 and the extracts fractionated by immunoaffinity chromatography [using a specific anti-CD38 antibody (A10 mAb) covalently linked to Sepharose protein A]. The purified Ag migrated as a single chain of Mr = 45,000 not associated with beta 2-microglobulin. Two-dimensional IEF gel electrophoresis revealed five spots (isoelectric point (pI) range: 6.5 to 6.9). After neuraminidase treatment, the mobility of the five polypeptides shifted to a more basic pI. Endoglycosidase-H treatment reduced the Mr of CD38 by 20%, revealing a broader band centered at Mr = 36,000. Treatment of CD38 molecule with V8 Staphylococcus aureus protease yielded a single dominant band at Mr = 38,000 which was still reactive with A10 mAb. The CD38 molecular was trypsin-resistant in both denatured or native conditions. These results clearly show the glycoprotein nature of CD38 molecule, which includes 2 to 4 N-linked oligosaccharide chains containing sialic acid residues. Furthermore, the present data indicate that the CD38 molecule does not display an apparent biochemical polymorphism among the different CD38+ cells or lines.

ADP-ribosyl Cyclase↗
PubMed1990

Murine monoclonal antibody recognizing a 90-kDa cell-surface determinant selectively lost by multi-drug-resistant variants of CEM cells.

We describe a murine IgG1 monoclonal antibody (MAb56), specific for a cell-surface protein structure (MC56 determinant) expressed by the human CEM cell line. A large band of approximately 90 kDa was identified as the main specific component of the MC56 determinant. Such a 90-kDa protein is significantly associated with the drug-sensitive phenotype, its expression being progressively reduced quantitatively in multi-drug-resistant (MDR) variants of CEM cells, according to the extent of drug resistance. In addition, the MC56 determinant is expressed de novo in drug-sensitive revertant cell lines derived from MDR cells and unreactive with the MAb56. The MAb56 shows a high affinity towards the immunizing drug-sensitive CEM cell line (Ka = 1.86 x 10(9) L/mole) while not binding to MDR cell variants. The expression of the MC56 molecule on a variety of human cells and tissues makes such a cellular determinant a candidate as a marker for studying the MDR phenomenon both in vivo and in vitro.

Animals↗
PubMed1990

Characterization by monoclonal antibody of a highly conserved antigenic determinant expressed on human platelet membranes and intermediate filament type III.

The murine monoclonal antibody (MoAb) CB21, raised after immunization with sonicated extracts of human platelets, has been shown to react with a line-restricted surface molecule and also a cytoplasmic structure displaying no restriction in terms of lineage and species. The surface structure recognized by the CB21 MoAb is exclusively expressed on the surface membrane of human platelets, being undetectable on other cells or lines so far tested. After permeabilization, the majority of the cells and lines tested with the CB21 MoAb displayed strong cytoplasmic reactivity with a constant typical filamentous distribution. Biochemical and morphological analyses showed that the cytoplasmic counterpart recognized by the CB21 MoAb is the intermediate filament type III.

Animals↗
PubMed1989

Microplate selection technique (MPST). A new method for selecting mouse transfectants expressing human gene products.

This paper examines the analytical power of fluorescence activated cell sorting and immunorosetting technique as compared with the newly devised microplate selection technique in identifying transfected murine L cells expressing human surface molecules. The microplate selection technique relies on the mechanical transfer of transfected cells to a terasaki microplate, where an indirect immunofluorescence assay is carried out. It is a simple procedure not requiring costly equipment and with a detection capacity equivalent to that of the fluorescence activated cell sorter. The microplate selection technique proved to be sensitive enough to detect all the transfectants produced during the present study.

Animals↗
PubMed1989

Generation and selection of monoclonal antibodies identifying surface molecules discriminating between fetal and adult fibroblasts.

The present report describes the reactivity of two murine monoclonal antibodies, i.e., CB11 and CB43, the first obtained by using embryonic material as immunizer and the second elicited against a human cell line. These reagents recognize two distinct molecules marking a peculiar differentiation stage on fetal/embryonic fibroblasts. The first structure is a single chain of 14.5 kd, the second one a heterodimer of 40-80 kd. Even if these reagents are not strictly fibroblast restricted, translineage expression does not diminish the medical relevance of the reagents; in fact, they may have application in prenatal diagnostics and amniocentesis testing, in which it is necessary to discriminate between fetal and maternal cells.

Adult↗
PubMed1989

Heat stable enterotoxin produced by Escherichia coli in acute diarrhoea.

We screened 569 children with acute onset diarrhoea from five Italian towns for heat stable enterotoxin produced by Escherichia coli. We compared an enzyme linked immunoabsorbent assay (ELISA) with the standard suckling mouse assay for detection of the enterotoxin. A total of 31 (5.4%) children were found who had strains of E coli that produced heat stable enterotoxin: 26 strains were positive in both tests, four only in the suckling mouse assay, and one only in the ELISA. Compared with the suckling mouse assay the sensitivity of the ELISA was 87% and the specificity was 99.8%. The mean age of the children with E coli that produced heat stable enterotoxin was 22 months. Fifteen (48%) of the children had ingested potentially contaminated food and five (17%) had a previous contact with someone with diarrhoea. The clinical picture was milder than that described in developing countries. Faecal osmolality and the osmolal gap were consistent with a secretory diarrhoea in 12 out of 15 (80%) of these children. The mean duration of the diarrhoea was five days. Heat stable enterotoxin produced by E coli is a common cause of mild diarrhoeal illness in Italian children.

Adolescent↗
PubMed1989

Characteristics and mechanism of action of a heat-stable enterotoxin produced by Klebsiella pneumoniae from infants with secretory diarrhea.

Escherichia coli heat-stable enterotoxins (ST) are classified into STa and STb according to their physicochemical and biologic characteristics. STa induces diarrhea, activating the guanylate cyclase-cGMP system. ST-like enterotoxins can be produced by bacteria other than E. coli, including Klebsiella pneumoniae. A Klebsiella ST has previously been shown to share some chemical and immunologic characteristics with E. coli ST. Aiming to define better the nature of Klebsiella ST, we have screened 237 children with diarrhea and 179 controls for ST-producing Klebsiella, using the SMA. We detected 26 Klebsiella strains from patients, two of which were positive in the SMA, and 36 from controls, all negative for ST. A partial purification was performed using an acetone precipitation followed by ultrafiltration and gel filtration techniques. Klebsiella toxin was heat-stable, methanol-soluble, sensitive to mercaptoethanol, active at acid pH values, but not at pH greater than 8. The time course of Klebsiella toxin in the SMA resembled that of E. coli STa. Klebsiella ST caused reduced Na absorption and net Cl secretion in rabbit ileal mucosa mounted in Ussing chambers. It was found to increase the cGMP but not the cAMP concentration. Finally, Klebsiella ST did not react with anti-E. coli STa MAb in a competitive ELISA. We conclude that K. pneumoniae may induce diarrhea through the production of an STa similar but not identical to E. coli STa.

Bacterial Toxins↗