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Biomedical subjects

C Rossi

Publications and source records attributed to C Rossi.

At least 181 records · Page 10Linked to original sources
PubMed1995

Synthesis of two distamycin analogues and their binding mode to d(CGCAAATTTGCG)2 in the 2:1 solution complexes as determined by two-dimensional 1H-NMR.

In the course of a study aimed at the synthesis of pyrrole amidine carboxamide DNA-binding agents as novel pharmacological agents, a series of carbamoyl analogues of distamycin, containing an increasing number of pyrrole units, have been obtained by total synthesis. The interaction of the tetrapyrrole carbamoyl 4 with the dodecamer d(CGCAAATTTGCG)2 in comparison with that of the corresponding formylamino analogue 3 has been examined by high-resolution 1H-NMR and molecular modeling. Either ligand binds to DNA in one-drug and symmetric two-drug modes at low drug:DNA ratios, while at high ratios only the two-drug complex was observed. In this article, the structure of 2:1 drugs DNA complexes has been studied by NMR and molecular modeling, which indicate that the two analogues bind the DNA in a similar fashion, in the minor groove of the 5'-AATTT region. In both complexes the two drugs are symmetrically placed along the complementary strands of DNA with the pyrrole ring of one molecule in close contact with those of the other one. Although another region of five consecutive A-T base pairs is available, no evidence of sliding of drug molecules between different binding sites, as in the case of the 2:1 complex of distamycin with the same dodecamer, is observed, thus indicating that increasing the number of N-methylpyrrolecarboxamide units from three to four cases a lengthening of the recognition sequence.

Base Sequence↗
PubMed1995

The use of thallium-201 in the preoperative detection of breast cancer: an adjunct to mammography and ultrasonography.

Thallium-201 breast scans were performed preoperatively in 72 female patients with breast abnormalities detected by mammography and/or ultrasonography (7.5-13 MHz), in order to differentiate benign from malignant breast disease. Informed consent was obtained from each patient. Scintigraphy consisted of anterior and oblique planar images of the affected breast and axilla at 10 min and 3 h following the injection of 201Tl chloride (110 MBq). All 201Tl scans were interpreted without prior knowledge of surgery data. Pathological features of breast malignancies, such as tumour size, axillary lymph node metastases, tumour grading, lymphatic vascular channel invasion and receptor status, were analysed for their association with 201Tl uptake by tumour cells. A total of 76 breast lesions were assessed in the study. On final histological diagnosis, there were 56 malignant tumours, 14 benign nodules (9 fibroadenomas, two cases of adenosis, two cases of focal fibrosis and one case of epitheliosis) and six atypical lesions (atypical ductal or lobular hyperplasia). Thallium scintigraphy was shown to have high accuracy (92%) in detecting breast cancer, better than mammography (74%) and ultrasonography (84%). Almost all (51/56) breast cancers showed greater 201Tl activity than surrounding normal breast tissue while there was no significant increase in 201Tl activity above background in all but one (19/20) case of non-malignant disease. 201Tl activity within breast tumours, calculated as tumour/background (T/B) ratio, ranged between 1.2 and 2.5 with a mean value of 1.45. In our experience the concentration of thallium in the breast cancer seems to be primarily dependent on vascularity and tumour size rather than tumour grading, lymphatic/vascular invasion or receptor status. 201Tl scan sensitivity was 97% for malignant lesions larger than 1.5 cm (n = 35) and 80% for lesions of 1.5 cm or less (n = 21); however, five of the eight breast cancers smaller than 1.0 cm were also detectable by 201Tl scintigraphy, compared with five out of seven by mammography. Thallium scintigraphy would not be useful in evaluating the axilla for lymph node metastases (sensitivity 27%, specificity 77%).

Adult↗
PubMed1995

Comparative investigations among meteorological conditions, air chemical-physical pollutants and airborne particulate mutagenicity: a long-term study (1990-1994) from a northern Italian town.

The findings of a continuos monitoring (Apr90-Mar94) on urban air quality of a Po Valley town are reported. Chemical-physical and genotoxicity data were detected. The results show the presence of mutagenic agents during the whole investigated period. Short term mutagenesis tests together with chemical-physical parameters analysis are able to better assess air quality and genotoxic risk for the population.

Air Pollutants↗
PubMed1995

Antigenicity of the rabbit hemorrhagic disease virus studied by its reactivity with monoclonal antibodies.

A panel of anti-rabbit hemorrhagic disease virus (anti-RHDV) monoclonal antibodies was produced and characterized. The ability of the MAbs to recognize epitopes present on RHDV capsids, European brown hare syndrome virus capsids and RHDV subunits was determined. Preliminary results on the neutralizing capacity of the MAbs were obtained by in vivo protection experiments. The antigenic map of RHDV obtained by this study is consistent with the current models of the calicivirus structure.

Animals↗
PubMed1995

Occupational genotoxicity assessment by mutagenicity assays.

Mutagenic activity measured by Ames test and by gene conversion, point mutation and mitochondrial mutability in Saccharomyces cerevisiae D7 strain was determined in the indoor environment of a glass factory. The results suggest that the increase in mutagenicity of air sample collected near the machinery is due to the thermal decomposition of oils. Modified assays were therefore compared for their ability to detect mutagens contained in urinary concentrates of exposed workers. The bacterial tests were performed by microsuspension assay in TA98, TA100 strains and in YG1024, YG1029 strains which overproduce O-acetyltransferase. Significant differences are evidenced both in the eukaryotic and prokaryotic systems.

Air Pollutants, Occupational↗
PubMed1995

Relationship between oral challenges with previously uningested egg and egg-specific IgE antibodies and skin prick tests in infants with food allergy.

BACKGROUND: Positive skin prick test (SPT) and RAST reactions to egg that had never previously been ingested have been observed in infants with food allergy. The likelihood of having clinical hypersensitivity reactions when egg is first ingested and the predictive value of SPT and RAST remain to be elucidated. OBJECTIVE: We investigated the relationship between egg-specific IgE antibodies and positive SPT reaction to egg, and the development of clinical hypersensitivity on the first exposure, in infants with food allergy. METHODS: The patient group consisted of 21 infants with food allergy and positive SPT and/or RAST reaction to egg, which they had never previously ingested; the control group of 12 infants had food allergy and negative test results. All subjects underwent double-blind placebo-controlled food challenges with egg. RESULTS: Thirteen of 21 patients (61%) and one of 12 control subjects (8%) had positive reactions to challenges (p < 0.01). Thirteen positive reactions to challenges (93%) elicited immediate symptoms. Late-onset eczema occurred in two children. SPT results showed a high sensitivity (0.92) and negative predictive accuracy (0.92), whereas specificity (0.57) and positive predictive accuracy (0.61) were poor. RAST did not have any diagnostic advantage over SPT. CONCLUSIONS: In infants with food allergy SPT with egg may be helpful in predicting which patients will react to the first exposure.

Child, Preschool↗
PubMed1995

A retroviral vector containing a muscle-specific enhancer drives gene expression only in differentiated muscle fibers.

Genetically modified myogenic cells have a number of potentially relevant applications for gene therapy of genetic defects. Retroviral vectors proved to be a safe and efficient tool to transfer and express genes into satellite cells and their differentiated progeny, although muscle-specific regulation of the transferred gene is very difficult to achieve in a conventional vector framework. We modified a Moloney murine leukemia virus (MoMLV)-derived retroviral vector containing a bacterial beta-galactosidase (beta-Gal) reporter gene by inserting a muscle creatinine kinase (MCK) enhancer element into the U3 region of the viral long terminal repeat (LTR). The resulting vector (mLBSN) was transferred into cells of different histological origin, including undifferentiated murine and human myogenic cells, which were unable to express the transgene at detectable levels. Instead, gene expression from the modified LTR was obtained in a mouse myogenic cell line and in human primary satellite cells upon induction of differentiation into myotubes in culture, and correlated with the activation of the muscle differentiation program. beta-Gal-negative, mLBSN-transduced human satellite cells were also transplanted into the quadricep muscle of immunodeficient mice, where activation of the transgene expression was observed in vivo after differentiation and fusion into muscle fibers. These results show that retroviral vectors carrying LTRs modified in the enhancer sequences may be used to target tissue- and differentiation-specific gene expression into the muscle. For practical purposes, satellite cells engineered by muscle-specific retroviral vectors might represent an effective tool to deliver expression of a given gene product specifically into the muscle tissue, avoiding undesired protein accumulation in mononucleated cells. More generally, this type of vector might be useful whenever regulated expression of a transferred gene is necessary in a target cell or tissue.

Animals↗
PubMed1995

Heterozygous factor VII deficiency and severe hemophilia A in the same kindred.

The association between heterozygous factor VII deficiency and severe hemophilia A in the same family is described. The 18-year-old proposita had a negative personal history for bleeding events and underwent clotting evaluation after a fortuitous finding of a prolonged PT. Decreased levels of both factor VII activity and antigen to about 50% of normal, compatible with heterozygous deficiency, were found in her and in three other asymptomatic siblings. Two uncles on the paternal side had severe hemophilia A and also showed low factor VII levels. However, in these two patients factor VII deficiency was secondary to chronic liver disease due to hepatitis B and C virus infections. Combined clotting defects in the same kindred may be due to an independent segregation of two separate defects or to common gene(s) malfunction. Factor VII deficiency is frequent and probably underestimated in the general population. For these reasons factor VII deficiency can easily segregate with other clotting defects.

Adolescent↗
PubMed1995

Transcriptional silencing of human immunodeficiency virus type 1 long terminal repeat-driven gene expression by the Krüppel-associated box repressor domain targeted to the transactivating response element.

The evolutionarily conserved protein domain, called the Krüppel-associated box (KRAB), present in the amino termini of a large number of Krüppel-type zinc finger proteins is a strong repressor domain. In order to develop novel strategies to control human immunodeficiency virus type 1 (HIV-1) gene expression, we constructed a series of expression vectors expressing the wild-type Tat or Tat transdominant negative mutants fused to the KRAB repressor domain. We found that the KRAB domain tethered to the transactivating response element is able to suppress both basal and Tat-mediated activity of HIV-1 long terminal repeat-driven gene expression. These results suggest that the KRAB repressor domain fused to the Tat transdominant negative mutants can be successfully employed to control HIV-1 gene expression.

Amino Acid Sequence↗
PubMed1995

3C-like protease of rabbit hemorrhagic disease virus: identification of cleavage sites in the ORF1 polyprotein and analysis of cleavage specificity.

Rabbit hemorrhagic disease virus, a positive-stranded RNA virus of the family Caliciviridae, encodes a trypsin-like cysteine protease as part of a large polyprotein. Upon expression in Escherichia coli, the protease releases itself from larger precursors by proteolytic cleavages at its N and C termini. Both cleavage sites were determined by N-terminal sequence analysis of the cleavage products. Cleavage at the N terminus of the protease occurred with high efficiency at an EG dipeptide at positions 1108 and 1109. Cleavage at the C terminus of the protease occurred with low efficiency at an ET dipeptide at positions 1251 and 1252. To study the cleavage specificity of the protease, amino acid substitutions were introduced at the P2, P1, and P1' positions at the cleavage site at the N-terminal boundary of the protease. This analysis showed that the amino acid at the P1 position is the most important determinant for substrate recognition. Only glutamic acid, glutamine, and aspartic acid were tolerated at this position. At the P1' position, glycine, serine, and alanine were the preferred substrates of the protease, but a number of amino acids with larger side chains were also tolerated. Substitutions at the P2 position had only little effect on the cleavage efficiency. Cell-free expression of the C-terminal half of the ORF1 polyprotein showed that the protease catalyzes cleavage at the junction of the RNA polymerase and the capsid protein. An EG dipeptide at positions 1767 and 1768 was identified as the putative cleavage site. Our data show that rabbit hemorrhagic disease virus encodes a trypsin-like cysteine protease that is similar to 3C proteases with regard to function and specificity but is more similar to 2A proteases with regard to size.

Amino Acid Sequence↗
PubMed1995

Two independent pathways of expression lead to self-assembly of the rabbit hemorrhagic disease virus capsid protein.

The rabbit hemorrhagic disease virus capsid protein was expressed in insect cells either as an individual protein species, from a mRNA analogous to the viral subgenomic RNA, or as part of a polyprotein that included the viral 3C-like protease and the RNA polymerase. Both pathways of expression led to the assembly of viruslike particles morphologically and antigenically similar to purified virus.

Animals↗
PubMed1995

Structure activity studies on chemically modified homologues of the antibiotic phytotoxic leucinostatin A.

The synthesis and a conformational study of a number of homologues of the well known antibiotic, phytotoxic leucinostatin A are reported. The circular dichroism of all the compounds are discussed. Some conclusions on the SAR of these compounds are drawn. The influence of the alpha-helical conformation and/or the increased lipophile character on their interesting biological activities is emphasized.

Amino Acid Sequence↗
PubMed1995

Flow cytometric analysis of c-myc oncoprotein in non-small-cell lung carcinoma: comparison with immunohistochemical results.

c-myc oncoprotein expression was evaluated in 36 non-small-cell lung carcinomas using immunohistochemical and flow cytometric analysis. Formalin fixed and paraffin embedded material was used. The same monoclonal antibody (mouse anti-human c-myc) was employed both for immunohistochemistry and flow cytometry. For the immunohistochemical evaluation we calculated the percentage of stained cells on 200 neoplastic cells. c-myc oncoprotein was measured using flow cytometry by linking the monoclonal with a secondary FITC-conjugated antibody; for each sample 20,000 events were analysed and the percentage of cells positive for green fluorescence was calculated. DNA content was obtained by propidium iodide staining. Results showed a high correlation between immunohistochemical and cytometric data, suggesting that flow cytometry could be used as an alternative to immunohistochemistry in evaluating nuclear antigens. Moreover, using flow cytometry information on DNA content can be obtained simultaneously.

Adenocarcinoma↗
PubMed1995

Can a specifically-aimed pathologic classification overcome the difficulties in defining HIV-associated lymphomas?

High grade B-cell systemic lymphomas in HIV-infected patients exhibit pleomorphic features as well as some overlap between established histologic subtypes thus highlighting the difficulties in defining them precisely by making use of the classifications for non-Hodgkin's lymphomas (NHL) proposed before the AIDS epidemic. A series of HIV-associated systemic lymphomas including 114 NHL and 25 Hodgkin's disease (HD) cases were morphologically and immunopheno-genotypically investigated at the Centro di Riferimento Oncologico, Aviano, Italy during a period of nine years. The International Working Formulation (WF) for NHL, the updated Kiel Classification and, later, morphologic variants of high grade B-cell NHL have been adopted in order to obtain a more detailed and specific histopathologic description of HIV-associated lymphomas. As a consequence of morphologic data, and considering also pathogenetic aspects as derived from literature, we have attempted a pathological categorization of HIV-associated systemic lymphomas based on the recognition of two main groups: the "blastic" cell group and the "anaplastic" one, both including specific cytomorphologic subtypes with, possibly, aggressive HD subtypes within one of them. This categorization uses the WF, the updated Kiel system, and the morphologic variants of high-grade lymphomas, and provides a provisional category for cases with intermediate morphologic features. Thus other histologic subtypes, such as small noncleaved cell (Burkitt) and immunoblastic lymphomas, can be defined in a more accurate way. The clear-cut placement of "anaplastic" cell lymphomas, including anaplastic large cell (CD30/Ki-1+) lymphomas, including anaplastic large cell (CD30/Ki-1+) lymphomas and possibly a proportion of HD cases, emphasizes the need for their diagnostic differentiation from polymorphic "blastic"' cell lymphomas, immunoblastic ones in particular.

Humans↗
PubMed1995

[Chemoembolization of hepatocarcinoma. Six years' experience].

This study was aimed at retrospectively assessing the effectiveness of transarterial chemoembolization by reviewing our six years' experience. From January, 1988, to December, 1993, chemoembolization was performed in more than 400 patients. Of them, 321 patients with complete follow-up were selected. The treatment was retrospectively analyzed according to survival rates. The average survival of chemoembolized patients is 12 months after the first treatment session. Average survival rates in Child A, B and C patients were, respectively, 13.79, 11.2 and 6.01 months. The patients were also divided according to tumor spread and the results follow: patients with single localizations had 15.19 months' survival, those with multiple localization 12.06 and those with tumor spread had 9.51 months' survival. The patients were divided into two groups: complete chemoembolization (group A) and incomplete chemoembolization (group B). The average survival was 15.95 months for 160 group A patients and 10.11 months for 161 group B patients. As for the number of chemoembolization sessions, 123 patients underwent only one session, 112 patients two sessions, 70 patients three, 12 patient four and 4 patients five sessions--625 sessions in all. Chemoembolization was performed every 3-4 months and was always preceded by a CT exam. Our patients were compared with an untreated group where average survival was 6.32 months. The value of CT after the first treatment in predicting survival was also studied. Finally, the methods used in all treatment are reported on, together with the general results and those in the different classes of patients.

Adult↗
PubMed1995

[Comparative evaluation of ultrasonography, computerized tomography, angiography and lipiodol CT in defining extent of hepatocarcinoma. A multicenter study].

The authors report the results of a multicentric trial on hepatocellular carcinoma (HCC) patients, whose lesions were confirmed with biopsy or by high (> 400 ng/ml) alpha-fetoprotein levels. The series consisted of 149 patients examined in 8 different centers and submitted to ultrasonography (US), Computed Tomography (CT) before and after contrast agent administration, angiography and Lipiodol CT. According to lesion size and number, the patients were divided with each imaging modality into three groups: a) group 1: unifocal HCC < 5 cm diameter; b) group 2: multifocal HCC with 2-3 nodules and/or tumor mass < 80 ml; c) multifocal HCC with more than 3 nodules (with total tumor mass not exceeding 40% of liver volume) or with total tumor mass > 80 ml. In 77 patients all the examinations were available for comparison. US and CT diagnosed more patients as belonging to group 1 than angiography and Lipiodol CT, while more patients were classified as groups 2 and 3 with angiography and Lipiodol CT, meaning that US and CT may understage some HCC cases (about 15%) because they show a lower number of nodules. This observation was confirmed by the direct comparison between US and Lipiodol CT (in 114 patients), CT and Lipiodol CT (in 103 patients) and angiography and Lipiodol CT (in 116 patients). US and Lipiodol CT were in disagreement in 18 cases, CT and Lipiodol CT in 16 cases and angiography and Lipiodol CT in 13 cases. In most of these cases, Lipiodol CT showed more lesions than the other techniques. The size of the undetected lesions was small, ranging few mm to 2 cm in nearly all cases. To conclude, the results of this multicentric trial show that Lipiodol CT is a fundamental tool to evaluate HCC extent. In contrast, conventional CT appeared not to add any significant piece of information and can therefore be excluded from the diagnostic protocol of HCC.

Angiography↗
PubMed1995

Lactate dehydrogenase activity of platelets in diabetes mellitus.

Lactate dehydrogenase (L-lactate : NAD+ oxidoreductase, EC 1.1.1.27) activity has been measured on the subpopulations of platelets obtained from blood of diabetic patients. Small, but not large platelets show a lactate dehydrogenase activity higher than that of controls. Moreover, a positive statistically significant correlation was found between the activity of small platelets and the percent of glycated haemoglobin, while no correlation was obtained in the case of large platelets. Since we previously demonstrated that lactate dehydrogenase activity of small platelets is exceedingly high in some clinical and experimental conditions, our results not only confirm the involvement of platelets in diabetes but provide more evidence in support of our previous hypothesis of a relationship between lactate dehydrogenase and in-vivo platelet activation.

Adult↗