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G Leo

Publications and source records attributed to G Leo.

At least 37 records · Page 2Linked to original sources
PubMed2000

Co-expression of thymidine kinase and cathepsin D in 200 primary breast carcinomas.

We assayed thymidine kinase (TK) and cathepsin D (Cath-D) in 200 breast carcinomas and we found that they were significantly correlated. This correlation was present in lymph node positive tumours, in G2 and G3, in T1 and in invasive ductal carcinomas. In addition, TK and Cath-D did not correlate with oestrogen receptor (ER) and progesterone receptor (PgR) status. We conclude that the relationship between Cath-D and TK may indicate a tumour population of high proliferation activity and invasiveness potential, related to a more aggressive phenotype, whose identification may be useful in defining prognosis.

Adult↗
PubMed2000

The p53 gene in patients under the age of 40 with gastric cancer: mutation rates are low but are associated with a cardiac location.

BACKGROUND: Determining both the frequency and the spectrum of p53 gene mutation in young patients with gastric cancer might provide clues to the host related genetic mechanism(s) in gastric carcinogenesis. PATIENTS AND METHODS: p53 mutations were assessed (by means of polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP), followed by DNA sequencing) in a cohort of 105 consecutive Italian patients in whom gastric cancer was ascertained before the age of 41. RESULTS: A low prevalence of p53 mutations (eight of 105) was observed, with no significant difference between intestinal (three of 31; 10%) and diffuse (five of 74; 7%) phenotypes. A significantly higher prevalence of p53 mutations was associated with the cardiac location (odds ratio, 7.09; confidence interval, 1.56 to 32.11). In all but one case, p53 mutations were associated with a stage higher than I. All eight mutations were located at CpG sites, where G : C to A : T transitions have been associated with frequent methylation at the C5 position of cytosine. CONCLUSIONS: These findings show that, unlike what has been consistently demonstrated in the general population, p53 mutations are uncommon in gastric cancer occurring in young patients, and in such patients, p53 alterations are significantly associated with the cardiac location.

Adolescent↗
PubMed1999

Changes in nicotinic acetylcholine receptor subunit mRNAs and nicotinic binding in spontaneously hypertensive stroke prone rats.

We have studied nicotinic acetylcholine receptors in spontaneously hypertensive 'stroke prone' (SHsp) rats. We found a significant decrease in 125I-alpha-bungarotoxin binding and alpha7 subunit mRNA levels in cortical areas of the SHsp rats with respect to Wistar Kyoto (WKy) normotensive rats. Antihypertensive drug treatment counteracted these changes in cerebral cortex but not in hippocampus. No significant change was instead found in [3H]-epibatidine binding and alpha4 and beta2 subunit mRNA levels. SHsp rats showed decreased latency at the active avoidance test and transiently increased threshold at both hot-plate and tail-flick tests in comparison with WKy rats. None of these behavioral parameters was correlated with 125I-alpha-bungarotoxin binding in cortical areas. In conclusion, present data show a preferential impairment of alpha-bungarotoxin sensitive nAChRs in SHsp rats.

Animals↗
PubMed1999

Biphasic Scatchard plots of oestrogen receptors are associated with low pS2 levels in human breast cancers.

In a series of 100 breast tumours, oestrogen receptors (ER) were analysed by Scatchard plots, progesterone receptors (PR) by enzyme immunoassay and pS2 by an immunoradiometric assay. Scatchard analysis gave information on receptor heterogeneity in that there was a large variation in Kd values obtained, from 0.001-2.95 nM. This variation was largely confined to tumours containing less than 70 fmol receptor per mg protein, while tumours with higher receptor concentrations were a more homogeneous population with low Kd values. An obvious correlation between ER and PR was found; moreover, pS2 was correlated to both ER and PR. In addition, 20 of the 100 tumours gave biphasic Scatchard plots, indicating the presence of at least two oestrogen-binding moieties, with Kd values and concentrations both in the range of those of receptors. The tumours displaying biphasic Scatchard plots had very low pS2 expression, regardless of ER concentrations; this was not true for PR. It is suggested that variability in responses to endocrine therapy may be related to the heterogeneity of the ER present in breast tumours.

Adult↗
PubMed1999

Computerised counting of tumour infiltrating lymphocytes in 90 breast cancer specimens.

Tumour infiltrating lymphocytes (TILs) implicated in immunologic cytotoxicity were evaluated by immunohistochemistry and digitally counted in serial sections from 90 breast cancers in order to assess their number, the relationships between them and to tumour histology. CD3+, CD4+, CD8+, CD20+, CD25+ and CD56+ lymphocytes were found in 58 (64.4%), 52 (57.7%), 50 (55.5%), 22 (24.4%), 11 (12.2%) and 21 (23.3%) tumours, respectively. There was no difference in the number of TILs between pure infiltrating ductal (NOS) and non-ductal carcinomas, and no relationship between TILs and histological grades was found. CD3+ TILs directly correlated to age, while lymph node negative patients had tumours infiltrated by fewer CD4+ TILs with respect to lymph node positive patients. In 25/90 patients, randomly chosen, the status of peripheral blood lymphocytes was evaluated but no differences with respect to the status found in healthy blood donors was obtained; nonetheless while in some patients CD8+ TILs outnumbered CD4+ TILs in situ, the CD4/CD8 ratio was normal in their peripheral blood. The results show a considerable diversity of TILs among breast tumours, their lack of relationship with the status of the peripheral blood cells, and their potential important relationship with age (CD3+) and lymph node status (CD4+).

Adult↗
PubMed1999

Third-generation assays for hepatitis C antibodies: a four-year study of pattern changes in patients with chronic and past infection.

BACKGROUND: Many advances have been made in the sensitivity of assays for hepatitis C virus antibodies (HCV-Ab). Nevertheless, polymerase chain reaction (PCR) is still the best method to establish if infection has become chronic. In this study we utilised third-generation assays for HCV-Ab in a four-year follow-up to determine the trend in antibody levels in currently and past infected patients. METHODS: Seventy-two multitransfused subjects were enrolled. All the patients were reactive at the first test with third-generation screening and confirmatory assays (ELISA-3 and RIBA-3) for HCV-Ab. They were subsequently retested in a follow-up ranging from 41 to 47 months. Viraemia was investigated with a standardised PCR kit; negative samples were reevaluated with nested PCR. Differences in antibody trend were calculated with the Wilcoxon signed-rank test. RESULTS: No statistical variation in antibody titre was found in the 41 HCV-RNA positive patients, although some of these showed a decrease in anti-c100p level. In contrast, anti-c22p, anti-c33c and anti-c100p levels decreased significantly in the 19 past infected patients. Twelve patients were HCV-RNA negative or intermittently positive with commercial PCR test, and consistently or intermittently positive in nested PCR: in these patients, antibody trend varied. CONCLUSIONS: Although resolving hepatitis is associated with a decrease in antibody titre, the trend should be observed for a long period to distinguish between chronic and past infection. However, the evaluation in a single patient can be unreliable. Since a doubtful response for HCV-RNA is in some cases obtained, further improvements in the diagnosis of chronic HCV infection are needed.

Adolescent↗
PubMed1999

[The prognostic significance of 99mTc-MDP breast scintigraphy. A comparison with histological and molecular parameters].

INTRODUCTION: Breast scintigraphy (BS) with the bone-seeking agent 99mTc-medronate (MDP) can be usefully combined with mammography to diagnose and characterize questionable breast lumps. However this radiotracer does not seem to provide any further prognostic information about breast cancer. Therefore we investigated the prognostic yield of MDP-BS searching for correlations between scintigraphic findings and the major biological and histologic parameters. MATERIALS AND METHODS: We retrospectively analyzed a series of 44 primary breast cancers. All patients had undergone 99mTc-MDP bone scan for preoperative staging, as well as conventional breast imaging. We statistically compared the cancer/background ratio (c/b index) with lesion histotype, diameter, grading, and the tissue concentrations of steroid receptors, cathepsine D, type 1 timidine kinase, pS2 and p53 proteins. RESULTS: MDP-BS failed to depict 11 of 44 lesions (O 0.5-2 cm), detected 7 of 16 mammographically questionable lesions and correctly visualized the two multifocal cases. Also, MDP-BS depicted no metastatic axillary lymph nodes. We found no statistically significant correlation between the c/b index and the prognostic markers. DISCUSSION AND CONCLUSIONS: Differently from BS with 99mTc-MIBI, 201T1, 18F-FDG, 111In-OCT and radiolabeled estrogens and despite its good overall accuracy, MDP-BS appears to have no prognostic role. In fact, despite the well-known capability of soft tissue lesions to take up the tracer, MDP tumor trapping seems to depend mainly on the increased permeability of neovessels and on interstitial space enlargement. Few reports are available in the literature on the correlation between in vivo MDP uptake by the breast cancer and prognostic parameters. Thus, we tested possible correlations between the amount of MDP taken up by the breast cancer, histologic features and cell concentrations of some major biomarkers. The lack of any statistical significance is in agreement with the theory, and confirms the little prognostic value of MDP-BS. Nevertheless, further trials are warranted on larger series of cases to validate our personal findings.

Adult↗
PubMed1997

Molecular biopathology of metaplastic, dysplastic, and neoplastic laryngeal epithelium.

In a large series of more than 100 cases of laryngeal carcinomas, the presence of steroid hormone receptors was demonstrated in the cytosol and in the nuclear fraction. Their presence was confirmed by the identification of estrogen receptor isophorms and by the detection of hormone-related proteins such as ER-D5. EGFr, and cathepsin D. These molecules were also variably expressed in normal, hyperplastic, and dysplastic epithelium. These data suggest a possible role of hormone receptors during laryngeal carcinogenesis. Finally, the presence of an Angiotensin II receptor was studied in neoplastic and preneoplastic laryngeal epithelium.

Carcinoma, Squamous Cell↗
PubMed1996

Polymorphism of angiotensin-converting enzyme gene in sarcoidosis.

Sarcoidosis is the disease in which increased levels of serum Angiotensin-converting enzyme (sACE) are most often detected. It has recently been shown that the deletion (D) or the insertion (I) of a 250bp-DNA fragment in the ACE gene accounts for three main ACE genotypes (i.e., II, ID, and DD) and for 47% of total phenotypic variance in sACE level. The aim of our work was to investigate whether or not patients with sarcoidosis have an increased incidence of those ACE genotypes coding for highest sACE levels and to investigate whether or not sACE level in sarcoidosis is related to ACE genotypes. We studied 61 unrelated patients with sarcoidosis (test group) and 80 unrelated healthy control subjects (control group). The ACE I and D alleles were detected with polymerase chain reaction on genomic DNA. In the control group we found an ACE genotype distribution that agreed with the Hardy-Weinberg proportion. The ACE genotype distribution was not significantly different in the test group. There was no correlation between ACE genotype and roentgenologic stage of sarcoidosis. Plotting the sACE level in the control group against ACE genotype, we found a trend of increasing mean sACE value according to the order II < ID < DD. The same trend for ACE genotype was found in the test group, in which it also paralleled the trend of sACE values plotted against roentgenologic stage, according to the order Stage I < Stage II < Stage III. We conclude that in sarcoidosis the ACE genotype distribution is not altered. The trends for increasing sACE values in sarcoidosis according to both ACE genotype and roentgenologic stage would suggest that both mechanisms play a role in determining sACE level.

Adult↗
PubMed1995

Synthesis and anti-HIV-1 activity of 4,5,6,7-tetrahydro-5-methylimidazo [4,5,1-jk][1,4]benzodiazepin-2(1H)-one (TIBO) derivatives. 3.

4,5,6,7-Tetrahydro-5-methylimidazo[4,5,1-jk][1,4]benzodiazepin-2 (1H)-ones (TIBO), 1, have been shown to significantly inhibit HIV-1 replication in vitro by interfering with the virus's reverse transcriptase enzyme. They have also demonstrated potential clinical efficacy in combating HIV-1, on the basis of a preliminary study. Our prior publications have discussed the discovery of this series of compounds and reported some preliminary chemical and biological studies around N-6 substitutions and 5-membered ring variations of 1. This manuscript describes our synthetic endeavors around 4, 5, and 7 mono- and disubstitutions of 1 and discusses related HIV-1 inhibitory structure-activity relationships. On the basis of inhibition of HIV-1's cytopathic effects in MT-4 cells, we found that 5-mono-Me-substituted analogues, the original substitution in the early lead compounds, and 7-mono-Me-substituted analogues of 1 were comparable as being consistently the most active compounds. Although generally less active, the 4,5,7-unsubstituted, 4-mono-substituted, cis- and trans-5,7-di-Me-substituted, and cis-4,5-di-Me-substituted analogues of 1 also exhibited some significant desired activity. The remaining trans-4,5-di-Me-substituted, cis- and trans-4,7-di-Me-substituted, and all 4,5-, 5,6-, 6,7-, and 7,8-fused disubstituted analogues of 1 possessed no noticeable desired activity.

Antiviral Agents↗
PubMed1995

Simian AIDS type D serogroup 2 retrovirus: isolation of an infectious molecular clone and sequence analyses of its envelope glycoprotein gene and 3' long terminal repeat.

We describe the molecular cloning of a serogroup 2 simian retrovirus (SRV; D2/RHE/OR) and present the sequence of its envelope (env) glycoprotein gene and 3' long terminal repeat region. This report documents the first infectious molecular clone of a serogroup 2 SRV and provides env sequence verification of genetic diversity among serogroup 2 SRV isolates.

Amino Acid Sequence↗
PubMed1995

Multiple isoforms of the oestrogen receptor in endometrial cancer.

We evaluated the presence and variability of oestrogen receptor (ER) isoforms in endometrial cancer by using [3H]oestradiol-labelled ERs and the H222 monoclonal antibody obtained from the Abbott enzyme immunoassay kit. Using isoelectric focusing (IEF), endometrial ER was shown to be composed of four different species, with pI values of 6.1, 6.3, 6.6 and 6.8, indistinguishable from the isoforms found in normal rat uterus, and human breast and larynx carcinomas. The isoforms at pI 6.3, 6.6 and 6.8, all sedimenting at 4S by sucrose gradient fractionation, showed, on two-dimensional SDS electrophoresis, relative masses of 50, 70 and 65 kDa respectively, equal to the masses previously found in breast cancer. These isoforms did not alter their pI values during IEF fractionation performed in a linear gradient of urea, while the pI 6.1, sedimenting at 8S, generated a new isoform at about 9 mol/l urea with pI 7.2 and a relative mass of 65 kDa. The urea-dissociated isoform (pI 7.2) was able approximately to double the antibody binding with respect to the nondissociated oligomer, which suggested that some epitopes are 'masked', i.e. not accessible to the antibodies when ER is present in its complexed form. The evidence thus suggested that the oligomer at pI 6.1 contained a single 65 kDa ER form which, as a monomer, focused at pI 7.2. The variability in the ER isoform profile found in endometrial cancer was similar to the variability previously reported in breast and larynx carcinomas. The balance between these isoforms could be a dynamic parameter involved in the functionality of this receptor and consequently in cell transformation.

Animals↗
PubMed1994

Interactions of P 1507, a new antioxidant agent, with phagocyte functions.

Toxic oxygen free radicals are believed to play a role in the pathogenesis of a number of respiratory diseases. In particular, pulmonary emphysema may occur because of the oxidative impairment of alpha 1-proteinase inhibitor (alpha 1-PI). We report in vitro data on a new thiol agent, P 1507 [N-5-(thioxo-L-prolyl)-L-cysteine], obtained in a series of experiments designed in view of its therapeutic potential in these clinical conditions. We found that P 1507 at the concentration of 5 x 10(-6) M was able to almost fully abolish the PMA-triggered PMN-induced oxidative impairment of alpha 1-PI. Protection may be due to the radical scavenger ability of P 1507, that markedly reduced superoxide anion production from PMNs. We also found that P 1507 did not significantly impair other defence mechanisms of PMNs (i.e. phagocytosis, chemotaxis and bactericidal activity). The release of cytokines (TNF-alpha, IL-6 and IL-8) from monocytes was not altered in the presence of P 1507. We conclude that the compound P 1507 may be considered for treatment of clinical conditions characterized by overload of oxidants, on the basis of its ability in preventing the oxidative damage of alpha 1-PI and of a lack of unwanted inhibitory effects towards defence mechanisms of phagocytes.

Antioxidants↗
PubMed1994

Relationships between tamoxifen binding proteins in primary breast cancer biopsies.

Using high-resolution isoelectric focusing gel electrophoresis (IEF), two tamoxifen binding sites (TBS) with isoelectric point (pI) values of 4.5 and 4.3 were identified, with different affinities for tamoxifen. The form at pI 4.3 (HTBS) displayed high affinity for the ligand (kD approximately 5 nM), while the protein at pI 4.5 (LTBS) had lower affinity (kD approximately 50 nM). LTBS was found in the microsomal fraction and HTBS in the cytosol. Of a total of 319 tumours studied, 257 were oestrogen receptor (ER) positive and 106 HTBS positive. In this combined group, thus able to bind tamoxifen either through the presence of ER or HTBS (or both), ER and PR were both negatively correlated with HTBS (P < 0.0001). The oestrogen-induced protein pS2 was assayed in 92 of the 319 tumours, and was also negatively (P < 0.0001) correlated with HTBS. The levels of HTBS were similar between infiltrating ductal carcinomas without special features (NOS) and non-NOS forms. However, HTBS concentrations were significantly higher in poorly differentiated grade 3 carcinomas than grade 2 (P < 0.05) and grade 1 (P < 0.01) forms. Conversely, ER concentration was lower in grade 3 than grade 1 forms (P < 0.05). Both the relationship between high affinity TBS and ER and the high concentration of HTBS in ER-poor grade 3 carcinomas may have a bearing on the known variability of tumour response to endocrine therapy and prognosis.

Adult↗
PubMed1994

Immunohistochemical and immunoradiometric evaluations of total cathepsin D in human larynx.

By using a commercially available immunoradiometric technique (Cath-D-IRMA, Cis BioInt.) the distribution of total cathepsin D (cath-D) in 30 malignant and in the corresponding histologically-proven non-malignant fragments obtained from lymph node negative patients suffering from larynx cancer was investigated. In both tissues the oestrogen and progesterone receptors were also assayed. In 17 out of the 30 samples, the cath-D was also assayed by immunohistochemistry using the M1G8, a mouse monoclonal antibody raised against cath-D (Cis BioInt.). Our data indicate that cath-D is present in prismatic cells of the normal laryngeal epithelium and in the cancerous cells. In cancerous larynx, the outer cell layer of large tumour nests showed the highest degree of immunoreactivity, while fibroblasts and inflammatory cells always showed a very faint staining. Cathepsin D levels were significantly higher (P < 0.0001) in the cancerous fragments (with a mean of 33 +/- 3.4 pmol/mg protein) than in the corresponding non-cancerous specimen (with a mean of 20.8 +/- 2 pmol/mg protein). A significant positive association (P < 0.001) between cath-D and progesterone receptor (PR) concentration values in the cancerous larynx was observed; accordingly, tumours expressing PR had significantly (P = 0.0005) higher cath-D levels than the tumours which did not contain the receptor. In contrast, such a relationship was absent in the non-malignant specimens. As regard the oestrogen receptor, no significant relationship between this and cath-D was observed. We conclude that cath-D measured by IRMA in tissue cytosols is mainly derived from cancerous cells, the contribution from fibroblasts and inflammatory cells being negligible. Cathepsin D overexpression and association with the PR in the malignant part of the larynx could indicate a possible role of the receptor in the biology of this disease.

Aged↗