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Biomedical subjects

A M Valentini

Publications and source records attributed to A M Valentini.

At least 19 recordsLinked to original sources
PubMed2005

Immunohistochemical and serological 90K/Mac-2BP detection in hepatocellular carcinoma patients: different behaviour of two monoclonal antibodies.

To clarify the biological role of the 90K/Mac-2BP glycoprotein, we evaluated the ability of two MAbs SP-2 and 1A4.22, to reveal this glycoprotein in both serum and tissue from hepatocellular carcinoma (HCC) patients. Tissue expression of 90K was detected by the immunohistochemical method in 20 HCC patients, while the 90K serum level was assessed by the ELISA assay in 13 HCC patients. MAb SP-2 was reactive only in serum, with a mean value of 12.8+/- 6.7 microg/ml . On the contrary, MAb 1A4.22 revealed immunoreactivity both in 92% of sera and in 60% of neoplastic samples. Positive staining was seen only in the epithelial cells and was cytoplasmic and granular in all instances. The mean 90K serum level assayed with MAb 1A4.22 was 29.4 +/- 13.7 microg/ml. Patients with a 90K serum level 30 microg/ml. Moreover, a possible poor prognostic role was observed for negative 90K in tissue. Our results suggest that only MAb 1A4.22 could demonstrate 90K glycoprotein expression in paraffin-embedded tissue and that this MAb could have a diagnostic and prognostic role in both sera and tissues from HCC patients.

Aged↗
PubMed2002

Demonstration of a direct stimulatory effect of bile salts on rat colonic epithelial cell proliferation.

BACKGROUND: Despite the clear demonstration that an increase in faecal bile salt concentration can augment colonocyte proliferation, it is still controversial whether bile salts act on these cells as direct mitogens or by inducing a damage-related proliferative response. The goal of this study was to define the mechanism mediating the proliferative effect of bile salts on rat colonocytes. METHODS: Faecal bile salt concentration was increased by feeding rats on diets enriched with either bile salts or fats. Colonic mucosa proliferating cell nuclear antigen (PCNA) expression, histology and apoptosis, and faecal water cytolytic activity were evaluated to assess proliferation and direct or indirect signs of mucosal damage. RESULTS: Compared to standard diet, chenodeoxycholate-, deoxycholate- and fat-enriched diets produced a significant increase in both faecal water total bile salt concentration (46.0 versus 124.1, 145.9 and 498.5 micromol/L, respectively) and percentage of PCNA-positive nuclei (30.5, versus 37.7, 33.9 and 47.1, respectively) that appeared significantly correlated (r = 0.8; P < 0.001). Chenodeoxycholate and deoxycholate fed animals showed colonic mucosa histology and faecal water cytolytic activity similar to controls, with a significantly reduced apoptotic index. Rats fed on high fat diet, however, showed a mild inflammatory infiltrate associated with an increased apoptosis and faecal water cytolytic activity, all conditions not apparently determined by the increased faecal water total bile salt concentration. CONCLUSIONS: The results obtained in this study demonstrate that bile salts act as direct mitogens on colonic epithelial cells.

Animals↗
PubMed2001

Increased oxidative stress in dimethylnitrosamine-induced liver fibrosis in the rat: effect of N-acetylcysteine and interferon-alpha.

Oxidative stress may represent a common link between chronic liver damage and hepatic fibrosis. Antioxidants and interferon seem to protect against hepatic stellate cell (HSC) activation and liver fibrosis. This study evaluated (1) the effect of the profibrotic agent dimethylnitrosamine (DMN) on the hepatic oxidative balance in the rat; (2) the role played by the antioxidant agent N-acetylcysteine (NAC); and (3) the antifibrotic effects of two different types of interferon-alpha: recombinant alpha-2b (rIFN-alpha) and leukocyte alpha (LeIFN-alpha). Five groups of rats received: (1) saline; (2) DMN; (3) DMN + NAC; (4) DMN + rIFN-alpha; and (5) DMN + LeIFN-alpha. Oxidative balance was evaluated by hepatic glutathione, TBARs, protein carbonyl, and sulfhydryl determination. Fibrosis was determined by hepatic hydroxyproline content and fibronectin (FN) staining (immunohistochemistry). DMN rats showed a diffuse FN deposition, an impaired oxidative balance, and higher hepatic hydroxyproline levels compared to that of controls. NAC administration significantly reduced FN deposition, increased hepatic glutathione, and decreased TBARs and protein carbonyls. Administration of IFN-alpha exerted different effects according to the type used. Both IFNs decreased FN deposition; however, LeIFN-alpha significantly improved histology and oxidative parameters compared to those of untreated DMN and rats treated with rIFN-alpha. This study shows the role of free radicals in this model of hepatic fibrosis; the protective effect of NAC against liver fibrosis; and the antifibrotic effect exerted by IFN-alpha (particularly LeIFN-alpha) independent of its antiviral activity.

Acetylcysteine↗
PubMed1998

Investigative burying by laboratory mice may involve non-functional, compulsive, behaviour.

The burying activity levels of albino mice offered a glass marble and a living scorpion on different occasions, were compared with the levels of exploration/investigation, avoidance, and displacement activities the same subjects performed during these and two other tests, the latter involving exploration with no particular stimulus-object and displacement with locomotion impossible. Although different average response levels were expected to occur in the different tests, it was assumed that the levels of related behavioural patterns correlated over the variation of individual mice. The scorpion elicited more burying than the marble, but the inanimate stimulus-object caused more avoidance. Exploration produced the only consistent, positive, correlation with burying in both female and male subjects. Only negative correlation occurred in males between burying and displacement, suggesting that these were alternative, in part non-functional, patterns. In females and males, while both touching and avoiding the marble decreased with experience over days, burying and displacement did not. The main conclusion is that burying began as an appropriate, investigative, activity, but, following frustrated investigation of the non-reactive stimulus-object, persisted as a compulsive stereotypy in subjects lacking in general experience, as laboratory rodents are in comparison with wild conspecifics. A simple model of compulsive disorder is proposed, in which initially appropriate behaviour goes on with inappropriate repetition when it does not attain its aim and the subject has internal difficulty in finding alternative patterns.

Aggression↗
PubMed1993

Can peanut agglutinin distinguish between pseudo and true invasion in colonic adenomas?

We verified the binding of peanut agglutinin (PNA) in 28 pedunculated adenomas (10 with pseudo and 18 with true invasion, respectively) of the large bowel. The distribution of glycoproteins was assessed in the normal mucosa of the stalk, in the surface dysplastic mucosa and in the mucosa of the pseudo-invasion or cancerization areas. The aims of the study were to verify: the PNA role in the differential diagnosis between pseudo and true invasion; the changes in PNA binding during transformation of mucosa from the normal to dysplastic and neoplastic status; the PNA ability as a predictive marker in the neoplastic transformation. The total percentage of PNA positivity in our samples was not significatively higher in carcinomatous than in pseudoinvasive areas (83.3% vs 50%). But the analysis of semiquantitative expression of PNA binding showed that an analogous, or reduced expression of marker in the epithelium in the submucosa compared to the dysplastic surface was consistent with the diagnosis of pseudoinvasion, while its increase strengthened the diagnosis of true invasion. In addition, we found a progressive increase of expression of PNA from the normal to dysplastic and neoplastic mucosa; therefore our data confirmed the quantitative relationship of this marker with malignant transformation. Finally, when we compared the expression of the PNA binding in solely superficial adenomatous tissue of benign and malignant polyps, we found an equal percentage of positive cases (66.6% in the carcinomatous vs 70% in the benign adenomas). Therefore, PNA does not recognize the risk of actual malignant evolution in an adenoma but is indicative of carcinomatous transformation when it is strongly positive.

Adenoma↗
PubMed1989

Composite carcinoid-adenocarcinoma of the stomach associated with multiple gastric carcinoids and nonantral gastric atrophy.

A case of multiple gastric carcinoids and nonantral atrophic gastritis in which the larger tumor was a composite carcinoid-adenocarcinoma is presented. The two components of the composite tumor immunohistochemically showed clear-cut diverging functional differentiations although the available evidence supported a common histogenesis from the metaplastic intestinal epithelium of the gastric mucosa. The carcinoid tissue of the composite tumor, which showed "atypical" features, also differed from the other, pure carcinoids, in which the histologic appearance was "typical." Total gastrectomy performed 1 month after the original gastric resection with antrectomy disclosed regressive changes in the endocrine cell proliferations of the gastric stump consistent with the withdrawal of a stimulating effect of the antral gastrin.

Adenocarcinoma↗
PubMed1987

[Vertebral fracture caused by electric cardioversion].

A case of vertebral fracture following DC shock for ventricular fibrillation is reported. After a short review of the complications of this procedure the case is described and compared with two other cases known in literature. We conclude that, although this complication is uncommon, it must be kept in mind owing to its potential severity.

Aged↗
PubMedDate not supplied

Overexpression of p53 in a large series of patients with hepatocellular carcinoma: a clinicopathological correlation.

p53 mutant protein has been found in a variety of human malignancies. In order to assess the controversial role of p53 protein in hepatocellular carcinoma (HCC) we studied its immunohistochemical expression in a series of 193 HCC specimens. Positive immunostaining for p53 was detected in the nuclei of neoplastic cells of 29 (15%) HCCs. There was no immunohistochemical evidence of mutant p53 expression either in normal or cirrhotic tissue surrounding neoplastic tissue. Higher alphafetoprotein serum levels were significantly associated with p53 overexpression. A prevalence of p53+ HCC specimens was seen in HCV negative patients (36% vs 13%, p < 0.05). No statistically significant correlations between p53 overexpression, age, sex, and HBV infection status were found. As regards histological grading, p53 was detected more frequently in tumours with poor cellular differentiation, although this finding does not reach statistical significance. The p53+ HCC rate was comparable to that attributed to the low incidence areas for HCC, in epidemiological studies. Moreover, p53 mutation seems to be related to the reactivation of alphafetoprotein gene to a more aggressive phenotype and to a later stage of liver carcinogenesis.

Aged↗
PubMedDate not supplied

Programmed cell death in colorectal carcinogenesis.

The most studied mechanism of malignant transformation has been cell proliferation. The relationship between programmed cell death (apoptosis), cell proliferation, and apoptosis regulatory genes (p53 and bcl-2), was studied in normal colonic epithelium, 26 sporadic adenomas both early and late, 25 FAP adenomas, and 34 carcinomas. We showed a decrease in programmed cell death and an increase in cell proliferation during the transition from adenoma to carcinoma. The increase of expression of p53 from early (10%) to late adenomas (87%) contrasted with the decrease of bcl-2 staining. Sixty-two per cent and 23% of carcinomas were reactive for p53 and bcl-2 respectively. Abnormal early activation of the bcl-2 gene, rather than late p53 gene mutation appears to be responsible for inhibition of apoptosis in colorectal carcinogenesis. bcl-2 was higher in FAP adenomas than in sporadic cases, and in carcinomas favouring the accumulation of long-living cells, which are more subject to mutation and thus cancerization.

Apoptosis↗
PubMedDate not supplied

Different human papillomavirus genotypes in ano-genital lesions.

In order to verify the frequency and physical state of some viral strains of Human Papillomavirus (HPV) in anogenital lesions, two-hundred and four specimens were studied. HPV/DNA was detected by using non isotopic in situ hybridization method, HPV-DNA was found in 25 lesions. The integrated pattern of HPV types 16/18 was found only in invasive carcinomas, the episomic one in all high risk lesions, never in invasive carcinomas. The low oncogenic risk genotypes 6/11 were detected only in condylomata acuminata, the high oncogenic risk genotypes 16/18 were found not only in cervical intraepithelial and invasive lesions, but also in a condyloma acuminatum. Our findings confirm the importance of the viral genotypes in the evaluation of the risk for malignancy. Therefore, the detection of a high risk viral genotype, independently of its physical state, can evoke the ghost of the malignancy also in a low risk cervical lesion.

Adult↗
PubMedDate not supplied

Immunohistochemical reactivity of anti-melanoma monoclonal antibody 225.28S in human breast cancer biopsies.

The high molecular weight melanoma-associated antigen, defined by murine monoclonal antibody (IgG1) 225.28S is largely expressed by melanoma cells and weakly expressed by other human tumors originating from neural crest. In this study, we analyzed the immunohistochemical reactivity of MoAb 225.28S in human breast cancer biopsies. A total of 92 breast cancer biopsies (66 infiltrating lobular and 26 infiltrating ductal carcinomas) were initially tested along with 26 melanomas (positive controls), 23 gastric/colonic adenocarcinomas and 13 neuroendocrine tumors. Forty-four out of 66 lobular breast carcinomas showed positive immunostaining with 225.28S MoAb as well as only 6 out of 26 infiltrating ductal histotype and 12 out of 26 melanomas. Conversely, gastric and colonic adenocarcinomas and neuroendocrine tumors were completely negative. The pattern of positivity in breast carcinomas was associated with malignant cells, rather than with the stroma or histiocytes infiltrating the lesions. Nonspecific cross-reactivity of 225.28S with breast carcinomas was excluded using a similar murine antithyreoglobulin MoAb, which gave negative staining in all biopsies. These results indicated that HMW-MAA or a similar sequence recognized by 225.28S MoAb is often expressed by lobular breast carcinomas but rarely by ductal adenocarcinomas. This seems to suggest that lobular breast carcinoma has common "ancestor" antigens with melanoma.

Antibodies, Monoclonal↗
PubMedDate not supplied

P-170 glycoprotein expression in gastric and colorectal carcinomas and normal mucosa. An immunocytochemical study.

During the past few years it has become apparent that simultaneous resistance of tumour cells to a number of heterocyclic drugs (multidrug resistance) is often correlated with overexpression of a P-glycoprotein (P-gp or P-170). P-gp expression can be studied by molecular biology and immunohistochemical techniques. The latter provide a rapid, sensitive and specific screening method suitable for testing even a relatively small number of tumour cells like those obtained at biopsy. The aim of this study was to detect and localize the immunohistochemical expression of P-gp in normal and neoplastic gastrointestinal tissue using the Mab JSB-1 in formalin-fixed paraffin-embedded specimens. A particularly striking finding of our study was the consistent, prevalent higher expression of P-gp in the stomach than in the colon, with a higher percentage of immunostaining in normal than in neoplastic tissue. This is in agreement with the fact that not only is the prognosis known to be worse for stomach cancer, but also the response to treatment is lower. Further studies should be carried out to verify the possibility of making routine tests of this kind for the evaluation of multidrug resistance, to guide the selection of patients for treatment of cancer with chemotherapeutic drugs.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMedDate not supplied

The immunohistochemical expression of cathepsin D in colorectal cancer.

It has been suggested that cathepsin D expression in stromal cells affects the prognosis of breast cancer. With reference to colon and breast cancer, this study verified cathepsin D immunostaining in epithelial and stromal cells of primary tumours and lymph-node metastases from 46 colorectal carcinomas. Eight of 46 cases (17%) were cathepsin D+ both in cancer and stromal cells. No staining was found either in cancer or stromal cells of the remaining cases. The results presented here suggest the possible paracrine influence of another diffusible factor produced by cancer cells which stimulates cathepsin D production in stromal and cancer cells.

Aged↗
PubMedDate not supplied

Immunohistochemical p53 overexpression correlated to c-erbB-2 and cathepsin D proteins in colorectal cancer.

The immunohistochemical overexpression of p53 protein in 42 large bowel cancers was correlated to c-erbB-2, cathepsin D (CD) proteins and other clinical and prognostic parameters. p53 overexpression (found in 60% of specimens) was positively associated with cathepsin D staining in stromal cells from older patients and better differentiated colorectal carcinomas (G1 + G2). Cytoplasmatic staining of c-erbB-2 protein was found in 58% of cases. No staining was observed at the cell membrane level. Our findings suggest that lower p53 expression in G3 carcinomas may be due to a high genomic instability, with the loss of both alleles of the gene. Therefore, these carcinomas were immunohistochemically silent. Although our series was small, the association between p53 nuclear neoplastic cells and CD stromal cells is interesting as regards the possible implications of these markers in colorectal cancer.

Cathepsin D↗
PubMedDate not supplied

Localization of p53 protein and human papillomavirus in laryngeal squamous lesions.

The p53 tumour suppressor protein can be ineffective because of mutations in the p53 gene or interactions with proteins synthesized by specific subtypes of HPV. We investigated the localization of p53 protein in association with HPV in paraffin sections of 10 dysplastic and 12 malignant laryngeal squamous epithelium specimens by using immunohistochemical and in situ hybridization techniques. Viral HPV type 16 or 18 related sequences were identified only in a squamous cell carcinoma (SCC) specimen. p53 was detected in 64% of cases studied. All p53+ specimens showed no HPVrelated sequences; the only HPV+ case was p53 negative. In our study, the increased p53 expression in the process from dysplastic to invasive SCC indicates that p53 overexpression is an early event in laryngeal carcinogenesis. Moreover, the systemic susceptibility to HPV infection suggests the need for an accurate evaluation of SCC risk not only in the genital tract in female patients shown to be positive for transforming HPV types (16 or 18).

Adult↗