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Biomedical subjects

A Mosca

Publications and source records attributed to A Mosca.

At least 37 records · Page 2Linked to original sources
PubMed1999

Posttranslational deamidation of proteins: the case of hemoglobin J Sardegna [alpha50(CD8)His-->Asn-->Asp].

Hemoglobin J Sardegna [alpha50(CD8)His-->Asn -->Asp] is a human Hb variant in which a posttranslational deamidation process takes place, transforming an Asn to an Asp residue. This variant, particularly widespread in northern Sardinia, has for the first time been characterized at the DNA level (codon 50 C-->A) on the selectively amplified alpha2-globin gene. We determined the protein and DNA sequences and performed cellulose acetate electrophoresis, isoelectric focusing, globin chain separation, stability tests with isopropanol and heat precipitation, and oxygen affinity analyses on whole blood to fully characterize the variant. A comprehensive review of the deamidation processes involving Asn and Gln residues in mutant proteins is reported, together with a discussion of the molecular mechanisms of such deamidations. Finally, examples of other proteins of clinical importance in which Asn or Gln residues have been implicated by DNA analysis alone are presented. These findings point out the importance of the complete characterization of variant proteins by use of both DNA and protein analyses.

Asparagine↗
PubMed1998

Cytokine effect on ex vivo expansion of haemopoietic stem cells from different human sources.

Human pluripotential stem cells (PSC) are currently the target for transplantation attempts and genetic manipulation. We have therefore investigated the frequency and the expansion potential of PSC's in different types of blood samples. CD 34+ cells were thus obtained from human bone marrow (BM), as well as from peripheral blood (PB) and cord blood (CB) samples. After immuno-magnetic separation the highest yields of CD 34+ cells were from BM (1.08-2.25%) and CB (0.42-1.32%) while PB samples gave much lower values. Suspension cultures of PSC's from the three sources were then set up, in the presence of combinations of haemopoietic growth factors. A remarkable amplification of the nucleated cell pool was observed reaching a maximum between 10 and 15 days of culture; earliest and maximum expansion (up to 220-fold) was achieved when Erythropoietin (Epo) was added to the culture medium, but this resulted in reduction of colony-forming cells and differentiation into erythroid progenitors. Clonogenic tests for BFU-E's derived colonies showed a peak value at 5 days of liquid culture. Further studies are advisable to establish the best cytokine combination for a valuable ex vivo expansion, coupled with preservation of stem cell properties.

Antigens, CD34↗
PubMed1998

Cytokine effect on ex vivo expansion of haemopoietic stem cells from different human sources.

Human pluripotential stem cells (PSC) are currently the target for transplantation attempts and genetic manipulation. We have therefore investigated the frequency and the expansion potential of PSC's in different types of blood samples. CD 34+ cells were thus obtained from human bone marrow (BM), as well as from peripheral blood (PB) and cord blood (CB) samples. After immuno-magnetic separation the highest yields of CD 34+ cells were from BM (1.08-2.25%) and CB (0.42-1.32%) while PB samples gave much lower values. Suspension cultures of PSC's from the three sources were then set up, in the presence of combinations of haemopoietic growth factors. A remarkable amplification of the nucleated cell pool was observed reaching a maximum between 10 and 15 days of culture; earliest and maximum expansion (up to 220-fold) was achieved when Erythropoietin (Epo) was added to the culture medium, but this resulted in reduction of colony-forming cells and differentiation into erythroid progenitors. Clonogenic tests for BFU-E's derived colonies showed a peak value at 5 days of liquid culture. Further studies are advisable to establish the best cytokine combination for a valuable ex vivo expansion, coupled with preservation of stem cell properties.

Antigens, CD34↗
PubMed1998

Cellular fatty acid composition, soluble-protein profile, and antimicrobial resistance pattern of Eubacterium lentum.

Phenotypic heterogeneity among isolates of Eubacterium lentum has been recognized for many years. To better delineate their taxonomic relatedness, 29 clinical isolates of E. lentum were examined for soluble-protein content, cellular fatty acid profile, and antimicrobial resistance pattern in order to ascertain whether differences in these characteristics could be correlated with differences in biochemical activities. Among 29 isolates we could identify 6 that were different from all the others. These strains were coccobacilli with translucent colonies; they were catalase and H2S negative, not fluorescent under UV light, and susceptible to beta-lactam drugs; growth was not stimulated by arginine; and fatty acid analysis revealed the presence of straight-chain fatty acids. The remainder of the strains, including the type species, were pleomorphic bacilli with speckled colonies and were catalase and H2S positive; all but two were fluorescent under UV light; they were resistant to beta-lactam antibiotics; growth was greatly stimulated by arginine; and they demonstrated saturated branched-chain fatty acids. Our data suggest that E. lentum can be further differentiated into different types.

Anti-Bacterial Agents↗
PubMed1998

Commutability of control materials in glycohemoglobin determinations.

The intermethod variabilities of control materials and patient blood samples for the measurement of glycohemoglobin were compared. Sets of 50 blood samples and 15 control materials were analyzed by HPLC and affinity and immunochemical methods. For each pair of methods, the distances of the materials from the regression line of patient blood results (expressed as normalized residuals) were calculated. Only two of 15 controls had normalized residuals exceeding 3 standard deviations from the regression line. Total hemoglobin (Hb) content, Hb derivatives, and cellulose acetate electrophoresis demonstrated that only a minority of controls could be considered similar to patients' blood samples. We selected Menarini's and our home-prepared controls to simulate calibration of the different techniques by these materials. Intermethod calibration succeeded mostly in harmonizing results obtained by HPLC methods. On the contrary, calibration of the immunochemical techniques (Boehringer and Roche) did not improve intermethod agreement to a clinically useful level.

Chromatography, Affinity↗
PubMed1998

Detection of anti-lipoarabinomannan antibodies for the diagnosis of active tuberculosis.

SETTING: A serological test that contributes in diagnosing tuberculosis would aid patient management. OBJECTIVE: To evaluate MycoDot, a new commercially available serological test, for the detection of immunoglobulin G antibodies to lipoarabinomannan (LAM), a glycolipid common to mycobacteria. DESIGN: Serum samples from 102 non-human immunodeficiency virus (HIV)-infected patients with no previous history of tuberculosis and with suspected active pulmonary (66) and/or extra-pulmonary (36) tuberculosis were investigated; 50 HIV-negative healthy subjects, sputum culture-negative, tuberculin skin test negative and with no history of tuberculosis, were used as controls. RESULTS AND CONCLUSION: In 28 patients with microbiologically ascertained tuberculosis 25/28 serum samples were positive, whereas the test was negative in two patients with renal tuberculosis and in one with pulmonary tuberculosis. The remaining 74 serum samples were negative. The follow-up of these patients excluded a mycobacterial infection. Control subjects were negative. On the basis of our design, the MycoDot test, with its rapidity and degree of sensitivity, is suitable for routine use in laboratory diagnosis of both pulmonary and extrapulmonary tuberculosis.

Adult↗
PubMed1997

Detection of Mycobacterium tuberculosis DNA in blood of patients with acute pulmonary tuberculosis by polymerase chain reaction and non-isotopic hybridisation assay.

The detection of Mycobacterium tuberculosis DNA in peripheral blood mononuclear cells (PBMC) by PCR and non-isotopic hybridisation assay was evaluated for the laboratory diagnosis of pulmonary M. tuberculosis infection. The PCR technique was based on the presence of IS6110, a DNA sequence specific for M. tuberculosis, and performed on PBMC from 30 patients belonging to the fifth group of the American Thoracic Society (ATS) classification of tuberculosis. The identification of amplification products was confirmed after electrophoresis by hybridisation with a non-isotopic probe in a DNA enzyme immunoassay (DEIA). Of the 30 blood samples studied by the PCR-DEIA technique, 26 gave positive results and four gave negative results. Blood samples from 30 subjects in a control group were negative by this technique. The data suggest that PCR-DEIA of blood may provide a sensitive, specific and useful means of diagnosing mycobacterial infection.

Bronchoalveolar Lavage Fluid↗
PubMed1997

Hb Puttelange [beta 140(H19)Ala-->Val] in an Italian man with polycythemia.

Hb Puttelange [beta 140(H18)Ala-->Val] was found in a 51-year-old Italian man who had mild polycythemia. The variant eluted from ion exchange high performance liquid chromatography at a position between Hb A and Hb A2. It comprised approximately 34% of the total hemoglobin, was weakly unstable and exhibited an increased oxygen affinity. Amplification of the beta-globin exons and nucleotide sequencing revealed a heterozygosity for a GCC-->GTC mutation in codon 140 corresponding to an Ala-->Val replacement. This substitution accounts for the altered functional properties, probably by producing indirect perturbation of the 2 3-diphosphoglycerate pocket through the nearby lysine residue at beta 82(EF6).

Chromatography, High Pressure Liquid↗
PubMed1997

A re-evaluation of glycohaemoglobin standardisation: the Italian experience with 119 laboratories and 12 methods.

The effect of calibration on glycohaemoglobin results was investigated in 119 laboratories where glycohaemoglobin (HbA1c) percentages were determined in triplicate in two samples and in two calibrators. The materials were human lyophilized haemolysates home-prepared with a novel protocol. The HbA1c content was assigned to calibrators using 4 HPLC methods with the data obtained from 11 laboratories. Intra-laboratory variation was low, although in 14 out of 119 laboratories CV values greater than 3.5% were reported. Calibration decreased inter-method variation from 16.3% to 5.6%, and from 15.3% to 4.2% for samples with low and high HbA1c content, respectively. Calibration decreased overall inter-laboratory variation from 18.7% to 7.4%, and from 17.2% to 5.4%. The calibrated results obtained with all methods, including Abbott IMx and Vision, were comparable.

Calibration↗
PubMed1996

Evaluation of penicillin susceptibility in clinical isolates of Streptococcus pneumoniae oxacillin resistant.

Antibiotic resistant pneumococci have been reported from all continents. Because of the importance of pneumococci in the aetiology of life-threatening diseases, the screening for penicillin resistance with oxacillin disc on all clinically significant isolates is suggested. However, discrepancy between the determination of penicillin resistance by oxacillin disc diffusion and the determination of penicillin minimum inhibitory concentration (MIC) has been reported. On this basis we have examined seven strains of Streptococcus pneumoniae isolated from patients recovered for the exacerbation of chronic bronchitis which were oxacillin-resistant. The assay of penicillin MICs showed that three isolates were moderately resistant to this agent, while four isolates resulted sensitive to penicillin as well as to cefotaxime. These results suggest that a further evaluation of penicillin MIC should be performed on those strains of S. pneumoniae resulting oxacillin-resistant.

Aged↗
PubMed1996

Simultaneous automated determination of glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase activities in whole blood.

We report a potentiometric fully automated method for determining red cell glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase activities and the glucose 6-phosphate dehydrogenase/6-phosphogluconate dehydrogenase index using 25 microliters of whole blood. No sample pre-treatment (e.g., preparation of the haemolysate) is needed and the measurements are performed at pH 8.0 and 37 degrees C under the conditions recommended by the ICSH committee. The reproducibility was constantly good, with within-run CV of 1.0% (glucose 6-phosphate dehydrogenase) and 5.9% (glucose 6-phosphate dehydrogenase/6-phosphogluconate dehydrogenase) for activities in glucose 6-phosphate dehydrogenase non-deficient adults, and of 2.3% (glucose 6-phosphate dehydrogenase, G6PD) and 2.5% (glucose 6-phosphate dehydrogenase/6-phosphogluconate dehydrogenase) for G6PDMediterranean heterozygotes. Linearity was observed up to an activity of 2800 U/l of glucose 6-phosphate dehydrogenase. Results of glucose 6-phosphate dehydrogenase activity (U/l) in whole blood (y) correlated well with those obtained with the previously described monostarter assay, performed at pH 9.2 (y = 0.60x + 37; n = 80; r = 0.991). Results of 6-phosphogluconate dehydrogenase (U/l) in whole blood (y) correlated well with those obtained by the ICSH recommended method (x) (y = 0.779x - 44; n = 23; r = 0.991). Reference intervals are reported for glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and glucose 6-phosphate dehydrogenase/6-phosphogluconate dehydrogenase index relatively to normal, beta- and alpha-thalassaemic glucose 6-phosphate dehydrogenase non-deficient adults, to glucose 6-phosphate dehydrogenase deficient adult males and to G6PDMediterranean non-thalassaemic heterozygotes. We demonstrate that the diagnostic sensitivity of the glucose 6-phosphate dehydrogenase/6-phosphogluconate dehydrogenase index in detecting the G6PDMediterranean heterozygotes is superior to that of the glucose 6-phosphate dehydrogenase activity alone.

Adolescent↗
PubMed1996

[The importance of microbiological study in the therapy of odontogenic abscesses. A report of a clinical case].

INTRODUCTION: The medical treatment (i.e. antibiotic therapy) of orofacial infections sometimes proves inadequate for the recovery of the patients. Therefore, aside the antibacterial treatment, both incision and drainage are necessary to remove the causal factors. CLINICAL CASE: In our report we show that in case of failure of classic antibacterial therapy, surgical treatment alone does not allow by itself the recovery of the patient if microorganisms developed resistance to antibiotics. CONCLUSION: Recent studies have demonstrated a prevalence of anaerobes in orofacial abscesses. On this basis it appears important that in the analysis of the bacterial flora the handling of samples is carried out in the proper way in order to ensure the isolation of both aerobic and anaerobic species as well as the antibiotic sensitivity.

Abscess↗
PubMed1995

Relationship between pharmacokinetics and pharmacodynamics of eptastigmine in young healthy volunteers.

Eptastigmine is a long-lasting acetyl-cholinesterase inhibitor, currently being developed for the symptomatic treatment of Alzheimer's disease. In the present study, we investigated the relationship between pharmacokinetics and pharmacodynamics of eptastigmine in young healthy volunteers. Eight male subjects received single oral doses of 10, 20, and 30 mg of eptastigmine and placebo according to a double-blind, randomized, crossover design. Blood was collected before and 0.5, 1, 1.5, 2, 3, 4, 6, and 24 hours after drug administration. Cholinesterase activity was measured using a potentiometric method in both plasma (butyryl-cholinesterase) and in red blood cells (acetyl-cholinesterase). Eptastigmine plasma levels were measured by a very sensitive high-performance liquid chromatography method (limit of quantitation 0.2 ng/mL). Eptastigmine plasma concentrations increased proportionally with the dose (mean +/- SEM AUC0-24 was 0.74 +/- 0.58, 3.61 +/- 1.15, and 6.25 +/- 1.51 ng.h/mL with 10, 20, and 30 mg, respectively) and were undetectable at 24 hours. The inhibition of acetyl-cholinesterase was dose-dependent (peak inhibition was 15 +/- 2%, 30 +/- 4%, and 36 +/- 6% with 10, 20, and 30 mg, respectively) and long-lasting, with a residual inhibition of 8 to 11% at 24 hours. Acetyl-cholinesterase inhibition and drug plasma levels were related over time with a counterclockwise hysteresis curve, suggesting the formation of active metabolites and/or a slow association to and dissociation from the enzyme in red blood cells. Butyryl-cholinesterase inhibition was weak and not dose-dependent (peak inhibition was 12 +/- 4%, 13 +/- 3%, and 12 +/- 2% with 10, 20, and 30 mg, respectively). The drug was well tolerated by all subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Preliminary evidence of endotoxic activity of Bilophila wadsworthia.

In this study we describe two properties of the Gram-negative bacterium Bilophila wadsworthia, namely the ability to clot Limulus lysate and the capacity to induce the production of tissue factor-like procoagulant activity by human mononuclear cells in vitro. Although exhibited at a lower degree when compared with those of typical Gram-negative bacteria or Gram-negative endotoxin those activities may account in part for Bilophila's pathogenicity. The capacity indeed to induce fibrin formation through the interaction with mononuclear cells suggests one mechanism by which the microorganism might cause abscess formation in the host. Moreover, since this activity is dependent on the number of Bilophila interacting with mononuclear cells, we hypothesize that this biological activity is closely influenced by growth environment.

Journal Article↗