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Biomedical subjects

S Marconi

Publications and source records attributed to S Marconi.

13 recordsLinked to original sources
PubMed2006

Anti-GD2-like IgM autoreactivity in multiple sclerosis patients.

Seric IgM autoreactivity in 100 multiple sclerosis (MS) and 106 control (70 of whom had other neurological diseases) patients was assessed either by immunohistochemistry on normal human CNS tissue or to GD2, GD1a, GD3 by ELISA and thin layer chromatography (TLC) techniques. By double immunohistochemistry, we found that 44% of the total MS population showed seric IgM reactivity to oligodendrocytes and myelin, this finding being particularly frequent in patients with secondary progressive MS. In the non-MS cohort, positive signals were seen only in one patient. In all cases, extraction of lipids from CNS sections abolished the immunoreactivity. Among the gangliosides investigated by ELISA, anti-GD2-like IgM autoantibodies were detected in the serum of 30% of MS patients, a subgroup of whom (below 10%) reacted also with GD1a and/or GD3. More than 85% of MS cases with anti-GD2-like IgM immunoreactivity by ELISA showed also IgM antioligodendrocyte/myelin staining by immunohistochemistry. However, no immunostaining in MS sera was observed when gangliosides were resolved by TLC. A positive correlation with neurological disability was observed, as the Expanded Disability Status Scale of MS patients with anti-GD2-like IgM autoreactivity by ELISA was significantly worse than seronegative MS cases. The results of the present study enforce the role of glycolipids as potential autoantigens and of IgM autoantibodies in MS pathogenesis.

Adult↗
PubMed2003

MAX, a novel retrotransposon of the BEL-Pao family, is nested within the Bari1 cluster at the heterochromatic h39 region of chromosome 2 in Drosophila melanogaster.

A homogeneous array of 80 tandem repeats of the Bari1 transposon is located in the pericentromeric h39 region of chromosome 2 of Drosophila melanogaster. Here, we report that the Bari1 cluster is interrupted by an 8556-bp insertion. DNA sequencing and database searches identified this insertion as a previously unannotated retrotransposon that we have named MAX. MAX possesses two ORFs; ORF1 putatively encodes a polyprotein comprising GAG and RT domains, while ORF2 could encode a 288-amino acid protein of unknown function. Alignment with the RT domains of known LTR retrotransposons shows that MAX belongs to the BEL-Pao family, which remarkable for its widespread presence in different taxa, including lower chordates. We have analyzed the distribution of MAX elements within representative species of the Sophophora subgroup and found that they are restricted to the species of the melanogaster complex, where they are heavily represented in the heterochromatin of all autosomes and on the Y chromosome.

Amino Acid Sequence↗
PubMed2001

Tyrosine kinase activation in breast carcinoma with correlation to HER-2/neu gene amplification and receptor overexpression.

The HER-2/neu oncogene encodes a transmembrane receptor with intrinsic tyrosine kinase activity. A pilot study was performed to investigate downstream effects of HER-2/neu (or related growth factor receptor) activation by identifying phosphorylated tyrosine. Fifty-four breast carcinomas were evaluated for HER-2/neu overexpression by the HercepTest (Dako, Carpinteria, CA) and the monoclonal CB11 antibody (Ventana, Tucson, AZ). Phosphotyrosine (an indication of tyrosine kinase activity) was detected by an antiphosphotyrosine mouse monoclonal antibody (Upstate Biotechnology, Lake Placid, NY). The gene amplification status was evaluated in 50 of the 54 cases by fluorescence in situ hybridization (FISH) using the Ventana gene probe. The HER-2/neu oncogene amplification was detected in 28% (14 of 50) of cases. Of the 14 cases showing oncogene amplification, tyrosine kinase activity was detected in 9 (64.2%) cases. There was moderate agreement between HER-2/neu gene amplification and tyrosine kinase activity (kappa = 0.43). Immunohistochemical staining of 3+ (with both HercepTest and CB11) showed better agreement with HER-2/neu oncogene amplification and increased tyrosine kinase activity than 2+ immunohistochemical staining. Overall, oncogene amplification and overexpression correlated with increased tyrosine kinase activity, supporting the mechanism of tyrosine kinase activation by HER-2/neu amplification and overexpression. However, 7 cases showing increased tyrosine kinase activity did not show gene amplification or 3+ receptor expression (by either HercepTest or CB11), raising the possibility of other growth factor receptors operating via the tyrosine kinase pathway. There was no apparent correlation between tyrosine kinase activity and hormone receptor status (estrogen or progesterone). Increased tyrosine kinase activity is more commonly associated with higher-grade tumors and thus may correlate with aggressive biologic behavior in breast carcinoma. The results of this pilot study suggest that a larger-scale investigation into downstream activation of tyrosine kinase and correlation to clinical outcome or response to Herceptin therapy may identify subsets of patients whose clinical response or outcome may be predicted by tyrosine kinase activation.

Adult↗
PubMed1999

Endoscopic biopsy pathology of Helicobacter pylori gastritis. Comparison of bacterial detection by immunohistochemistry and Genta stain.

OBJECTIVES: To describe the endoscopic biopsy pathology of Helicobacter pylori gastritis, compare bacterial detection by immunohistochemistry using a specific antibody with the Genta stain, and to compare the relative costs of the 2 techniques. DESIGN: One hundred cases of gastritis identified as positive for H pylori by Genta stain and 100 cases considered negative by the same technique were stained using an anti-H pylori-specific polyclonal antibody. Laboratory reagent and labor costs for the 2 methods were compared. RESULTS: Chronic active gastritis with lymphoid follicles was significantly associated with H pylori infection (P <.0001). The immunohistochemical method had a sensitivity of 97% and a specificity of 98% compared with the Genta stain, with strong agreement for grading density of organisms (kappa = 0.85; P <.001). Reagent costs were similar for both methods, but immunohistochemistry using an autoimmunostainer required less dedicated technical time and hence was less expensive than the Genta stain. CONCLUSIONS: Immunohistochemistry using a specific antibody is an accurate and cost-effective method for H pylori detection in gastric biopsies.

Biopsy↗
PubMed1998

Delayed involution of the mammary epithelium in BALB/c-p53null mice.

In mammals, weaning of neonates and subsequent milk stasis initiates removal of the secretory epithelium of the mammary gland by apoptosis. The p53 tumor suppressor gene is induced rapidly following weaning of neonates, but its role in the process of involution has not been defined. Therefore, experiments were performed to identify the cell types in which the p53 gene is expressed during involution and determine the consequences of its absence in BALB/c-p53null mice. Both p53 mRNA and protein were detected in the mammary epithelium within 48 h following weaning and resulted in an eightfold increase in levels of p21WAF1 mRNA. Induction of p21WAF1 mRNA was absent in BALB/c-p53null mice, and therefore, was shown to be p53-dependent. The BALB/c-p53null mice exhibited delayed involution of the mammary epithelium, as measured by 60% greater epithelial area compared to BALB/c-p53(wt) mice through 5 days post-weaning. The delay was transient with no differences being apparent at 7 days post-weaning. Expression of the stromal protease stromelysin-1 was unaffected by the absence of p53 suggesting that stromal responses were intact. These data demonstrate that p53 participates in the first stage of involution initiated by the epithelium itself, but does not affect the second phase during which stromal proteases are induced.

Animals↗
PubMed1993

1H-NMR study of reduced heme proteins myoglobin and cytochrome P450.

The 1H-NMR spectra of deoxymyoglobin and reduced cytochrome P450 are analyzed by NOE spectroscopy. Progress has been made in the assignment of the hyperfine-shifted signals of deoxymyoglobin. The nuclear longitudinal-relaxation-time values indicate short electron-relaxation times whereas Curie relaxation contributes significantly to the signals linewidths. For reduced cytochrome P450 the linewidths are larger due to the Curie-relaxation contribution in a large protein. Therefore, the spectral information is poor. The electron-relaxation rates are discussed in terms of possible electronic structure.

Animals↗
PubMedDate not supplied

[Quantitative study and typization of aerobic bacteria in the conjunctival sacs of healthy eyes].

We carried out a qualitative and quantitative bacteriological research into the conjunctives of 220 subjects in good health mostly women (180) exempt from recent or previous eyes diseases. In order to gather conjunctival bacteria we employed with a few variations Hadley's et al. (1973 [12]) method. Among the calculated bacterial flora we found as the most numerous ones Staphylococcus epidermidis (mean valor 1960/ml), then Streptococci (480/ml), Micrococci (465/ml), Diphteroides (360/ml), Enterococci (77/ml) and numerous (700/ml) Gram-positives Cocci like Sarcina, Micrococcus tetragenes, Diplococcus, and very rarely bacterial genera Gram-negatives or Iphomycetes, also numerically inferior as regards the researches of other Authors, because owen study is carried by into eyes exempt from diseases.

Adolescent↗
PubMedDate not supplied

[Quantitative bacterial ecology of normal nasal mucosa].

A quantitative research into the aerobic bacteria of human nasal cavities has been carried out; 183 healthy individuals observed, negative results 18 (9.83%). Streptococcus, Enterococcus, Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus, Streptococcus pneumoniae, Neisseria, were numerically determined and the incidence of each single species or genus exactly specified. Among gram-negative bacteria, Enterobacter, Providencia, Proteus, Citrobacter freundii, Haemophilus influenzae, Klebsiella pneumoniae, Escherichia coli, Serratia, Herella, Pseudomonas, and among the Hyphomycetes, Candida albicans have been identified and their number calculated. Diphteroid bacteria were also detected and counted; among them, the Corynebacterium pseudodiphtheriticum seemed to be the most frequent and numerous species. Finally, interference phenomena in vivo by Staphylococcus aureus and environmental and nourishment competition by Staphylococcus epidermidis, Streptococcus and Diphtheroids were noted.

Adult↗