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A Modesti

Publications and source records attributed to A Modesti.

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

Small early gastric cancer with special reference to macrophage infiltration.

The authors investigate the tumor-infiltrating cells in small early gastric cancer (EGC) (<10 mm) and describe the ultrastructural features and interactions of macrophages with tumor cells and other inflammatory cells. Sections from 20 small EGCs were stained by immunohistochemical methods for CD20, UCHL1, CD4, CD8, and CD68 (electron microscopic examination was used in 6 of the 20). In all of the tumors, CD68-positive macrophages accounted for most tumor-infiltrating cells, with UCHL1-positive T lymphocytes, eosinophils, and neutrophils being the next most frequent. We found only a few CD20-positive B lymphocytes. Electron microscopic analysis revealed macrophages with many phagocytic vesicles, cellular debris, and apoptotic bodies. These morphologic data show that macrophages are actively phagocytic. The tumor cells in contact with macrophages showed no cytopathic changes. These data do not support a macrophage-mediated cancer lysis like the ones reported in some systems in vitro. Contacts among macrophages and other inflammatory cells formed a recurrent ultrastructural hallmark and suggest a communication among varying inflammatory cell types during the precocious host response to gastric neoplasia.

Adenocarcinoma↗
PubMed1999

Analysis of mammary carcinoma onset and progression in HER-2/neu oncogene transgenic mice reveals a lobular origin.

Morphologic examinations of mammary neoplasias arising in BALB/c (H-2d) mice carrying the activated rat HER-2/neu oncogene (BALB-NeuT), and in FVB (H-2q) mice bearing the wild-type proto-oncogene (FVB-NeuN), indicate that both conditions result in a very human-like lobular carcinoma of alveolar type, whose histotype is the result of the preferential expression of HER-2/neu products in the epithelium of lobular ducts and lobules. Detailed analysis of tumor progression indicates that transition from lobular hyperplasia to overt carcinoma is associated with a high epithelial proliferation rate, as assessed by anti-proliferating cell nuclear antigen immunostaining, and coincides with the activation and maximal extension of tumor angiogenic process as assessed by microvessel count (anti-CD31), anti-beta3 integrin, and anti-laminin immunostaining. Neovascularization is accompanied by vascular endothelial cell growth factor and basic fibroblast growth factor production by hyperplastic epithelial cells. By contrast with the BALB-NeuT tumors, E-cadherin expression is almost nonexistent in those arising in FVB-NeuN mice and this may explain their high metastatic potential. Despite their different kinetics, however, the lung metastases observed in both strains are histologically similar and resemble the primary tumor. Both strains can thus be proposed as models for "in vivo" investigation of the origin and progression of the alveolar type of lobular mammary carcinoma and the testing of new therapeutic approaches.

Animals↗
PubMed1998

Cloning of murine low molecular weight phosphotyrosine protein phosphatase cDNA: identification of a new isoform.

The low molecular weight phosphotyrosine protein phosphatase (LMW-PTP) is a 18 kDa cytosolic enzyme, involved in the negative regulation of cell proliferation. In different mammalian species LMW-PTPs are expressed in two molecular forms produced from a single primary transcript through an alternative splicing mechanism. In this paper we report the cloning, expression and characterization of mouse isoforms of LMW-PTPs (called m-IF1 and m-IF2), very similar to the corresponding rat and human isoenzymes. Moreover we have identified a third cDNA encoding a protein (m-IF2P) that presents three substitutions compared to m-IF2. This new isoform is still active on pNPP, although to a lower extent: this reduction is mainly due to the leucine to proline substitution in position 13, within the catalytic loop. The mRNA expression level of this isoform is comparable to those of m-IF1 and m-IF2. It is likely that a gene duplication process followed by mutations has generated this new gene.

3T3 Cells↗
PubMed1998

Coexpression of IL-6 and soluble IL-6R causes nodular regenerative hyperplasia and adenomas of the liver.

Studies with tumor necrosis factor p55 receptor- and interleukin-6 (IL-6)-deficient mice have shown that IL-6 is required for hepatocyte proliferation and reconstitution of the liver mass after partial hepatectomy. The biological activities of IL-6 are potentiated when this cytokine binds soluble forms of its specific receptor subunit (sIL-6R) and the resulting complex interacts with the transmembrane signaling chain gp130. We show here that double transgenic mice expressing high levels of both human IL-6 and sIL-6R under the control of liver-specific promoters spontaneously develop nodules of hepatocellular hyperplasia around periportal spaces and present signs of sustained hepatocyte proliferation. The resulting picture is identical to that of human nodular regenerative hyperplasia, a condition frequently associated with immunological and myeloproliferative disorders. In high expressors, hyperplastic lesions progress with time into discrete liver adenomas. These data strongly suggest that the IL-6/sIL-6R complex is both a primary stimulus to hepatocyte proliferation and a pathogenic factor of hepatocellular transformation.

Adenoma↗
PubMed1998

Interleukin 12-mediated prevention of spontaneous mammary adenocarcinomas in two lines of Her-2/neu transgenic mice.

The ability of interleukin (IL)-12 to prevent tumors when administered to individuals with a genetic risk of cancer was studied in two lines of transgenic mice expressing rat HER-2/neu oncogene in the mammary gland. Female BALB/c (H-2(d)) mice carrying the activated HER-2/ neu oncogene show no morphological abnormalities of the mammary gland until 3 wk of age. They then progress through atypical hyperplasia to in situ lobular carcinoma and at 33 wk of age all 10 mammary glands display invasive carcinomas. Adult FVB mice (H-2(q)) carrying the HER-2/neu protooncogene develop mammary carcinomas with a longer latency (38-49 wk) and a lower multiplicity (mean of 2.6 tumors/mice). Treatment with IL-12 (5 daily intraperitoneal injections, 1 wk on, 3 wk off; the first course with 50 ng IL-12/day, the second with 100 ng IL-12/day) begun at 2 wk of age in BALB/c mice and at 21 wk of age in FVB mice markedly delayed tumor onset and reduced tumor multiplicity. Analogous results were obtained in immunocompetent and permanently CD8(+) T lymphocyte-depleted mice. In both transgenic lines, tumor inhibition was associated with mammary infiltration of reactive cells, production of cytokines and inducible nitric oxide synthase, and reduction in microvessel number, in combination with a high degree of hemorrhagic necrosis.

Animals↗
PubMed1998

Cloning, expression and characterisation of a new human low Mr phosphotyrosine protein phosphatase originating by alternative splicing.

RT-PCR experiments on RNA from K562 and HepG2 cells and from human placenta led to the isolation of a novel cDNA, a further alternative splicing product of the primary transcript of low Mr phosphotyrosine phosphatase (LMW-PTP), already known to produce isoforms 1 and 2. This new transcript represents 15-20% of the total LMW-PTP mRNA in the cell. This novel cDNA codifies for a protein that we have named SV3 (splicing variant 3): the deduced protein sequence presents the first 49 residues identical to those of isoform 1, followed by 24 unrelated amino acids, due to a frameshift introduced at the novel exon-exon boundary. The SV3 protein, expressed in E. coli is enzymatically inactive, most probably because unfolded, as suggested by far-UV circular dichroism (CD) experiments. SV3 protein appears to possess the characteristics of an unstructured polypeptide chain lacking the packing of side chain residues and the secondary structure level that are typical of globular proteins. This protein could represent an inactive variant of the human LMW-PTP.

Alternative Splicing↗
PubMed1998

Lymphocyte proliferative response in brown bears: cytokine role and glucocorticoid effect.

Lymphocyte stimulation and proliferation play a pivotal role in the immune response to soluble as well as to cellular, bacterial, and viral antigens. In this study, peripheral blood mononuclear cells (PBMC), mainly composed of lymphocytes, were separated by Ficoll-Hypaque density gradient centrifugation from 50-ml jugular vein blood samples drawn from six captive and five wild-caught brown bears (Ursus arctos) (eight Apennine brown bears from the Italian population; three of undetermined origin). Stimulation of cultured bear PBMC with the two classical T lymphocyte mitogens phytohemagglutinin (PHA) and Concanavalin A (ConA) was followed by a significantly greater proliferative response than that shown by human PBMC (n = 11) (PHA: T = 4.03, d.f. = 20, P = 0.001; ConA: T = 4.25, d.f. = 20, P < 0.0005; Student's t-test, oneway ANOVA). As in humans, the PBMC proliferative response in bears was markedly (> 50%) inhibited by addition of transforming growth factor beta (TGF beta) human recombinant cytokine to the culture. Further fractionation provided a cell preparation extremely rich in peripheral blood lymphocytes (PBL) (mean +/- SD = 96.1 +/- 1.7%). Addition of interleukin 1 (IL1) or interleukin 2 (IL2) human recombinant cytokines to cultured PBL stimulated with a suboptimal concentration of mitogens resulted in a ninefold increase in the lymphocyte proliferative response. Dexamethasone (DEX, a synthetic analog of hydrocortisone) inhibited the bear PBMC proliferative response by 22.2 +/- 4.3% (mean +/- SD), compared with 46.2 +/- 6.9% and 91.8 +/- 8.1% (mean +/- SD) in humans and mice (n = 11) (Mus domesticus), respectively. Inhibition of the brown bear and human PBMC responses was markedly (> 60%) reduced by the addition of IL2. The finding that IL1 and IL2 augment and that DEX inhibits bear lymphocyte proliferative response suggests that these cytokines can be used to increase the immune response in vaccinations, and that DEX may hamper several immunologically mediated diseases.

Animals↗
PubMed1998

Interaction between endothelial cells and the secreted cytokine drives the fate of an IL4- or an IL5-transduced tumour.

Injection of interleukin-4 (IL4) gene-transduced tumour cells into syngeneic immunocompetent mice resulted in tumour rejection in which a key role for eosinophils was suggested. To evaluate whether IL5 inhibits tumour growth by selectively inducing eosinophil recruitment and activation, a poorly differentiated mammary adenocarcinoma cell line (TSA) was transfected with the IL5 gene and the cells secreting IL5 (TSA-IL5) were injected subcutaneously (s.c.) in syngeneic mice. The oncogenicity of TSA-IL5 was compared with that exhibited by TSA cells transfected with the IL4 gene (TSA-IL4) and with the neomycin resistance gene only (TSA-neo). At progressive times after subcutaneous challenge, tumour growth areas were studied histologically, ultrastructurally, and immunohistochemically to identify the reactive cells, visualize tumour vessels, and detect the cytokines and chemokines involved in the anti-tumour reaction. Both the morphological and the functional data showed that TSA-IL5, despite the large eosinophil infiltrate, grew progressively like TSA-neo, suggesting that eosinophils per se do not play a crucial role in TSA tumour rejection. Furthermore, our data indicate that the rejection of TSA-IL4 depends on the IL4-induced expression of VCAM-1 and MCP-1 by endothelial cells. MCP-1 together with VCAM-1 results in recruitment and activation of basophils, mast cells, and macrophages, and hence a pro-inflammatory cytokine cascade that initially favours the influx and activation of neutrophils and finally tumour rejection. In this context, the rejection of TSA-IL4 seems to involve a variety of reactive cells and rests on a continuous cross-talk between basophils, mast cells, macrophages, CD8-positive lymphocytes, and granulocyte subsets, mostly neutrophils.

Animals↗
PubMed1998

Effect of chronic hyperoxia on young and old rat carotid body ultrastructure.

Morphologic, physiological, and biochemical changes occur in the carotid body (CB) during postnatal development in relation to physiological requirements. Chronic normobaric hyperoxia attenuates the carotid chemosensory response to hypoxia. During aging there is less of a CB response to hypoxia, which results in a reduced ventilatory adaptation and chemosensory discharge. To test if the oxygen-sensitive mechanism is affected by chronic hyperoxia in an age-dependent fashion, we have studied structural and ultrastructural aspects of young and old rat CBs. Four groups of six male Wistar rats were used. One group of two-month-old rats and another of 25-month-old rats were kept at room air. The other two groups, age matched, were exposed to 98-100% O2, for 60-65 h, in a large Plexiglas chamber. The rats were anesthetized, CBs were fixed in situ with glutaraldehyde (2.5% in phosphate buffer. pH 7.4, 320 mOsm), and were prepared for electron microscopy. Young hyperoxic rats showed focal necrosis in type I cells, along with an increase of endoplasmic reticulum, Golgi apparatus, and of mitochondria volume, with loss of cristae. These changes were less pronounced in the older rat CBs compared with the young rats. In conclusion, hyperoxia seems to affect the oxygen-sensitive mechanism in the carotid body cells, and the reduced effects shown in the old rat CBs suggest an age-related decreased sensitivity to oxygen.

Aging↗
PubMed1998

Group B streptococci persist inside macrophages.

Group B streptococci (GBS) are an important cause of neonatal sepsis, pneumonia and meningitis. In the early phase of infection, macrophages and polymorphonuclear cells (PMN) are the first immune cells that interact with GBS. In this in vitro study, to gain insight into GBS-macrophage interaction in the absence of type-specific antibodies, we examined the features of GBS survival in thioglycollate-elicited murine peritoneal macrophages and the effect of GBS on the protein kinase C (PKC)-dependent transduction pathway. Our results demonstrate that type Ia GBS, strain 090 (GBS-Ia) and type III GBS strain COH 31r/s (GBS-III), after in vitro phagocytosis survive and persist intracellularly in macrophages for up to 24 and 48 hr, respectively. However, macrophage activation by interferon-gamma (IFN-gamma) and lipopolysaccharide from Escherichia coli (LPS) caused a significant reduction in the time of intracellular persistence. Macrophage activation by IFN-gamma and LPS seems to be a multifactorial event involving multiple intracellular signal pathways also including PKC. Since PKC is one of the components in the signal network leading to macrophage activation and an important target for several intracellular micro-organisms, we wondered whether PKC could have a role in intracellular GBS survival. Both PKC depletion by treatment with phorbol 12-myristate 13-acetate (PMA) for 18 hr and PKC inhibition by Calphostin C rendered macrophages more permissive for the intracellular GBS survival. Furthermore, GBS-infected macrophages were unable to respond to PMA and LPS, activators of PKC, by inducing antimicrobial activity. The ability of GBS to impair PKC-dependent cell signalling was also demonstrated by the reduced c-fos gene expression in GBS-infected macrophages with respect to control macrophages, after LPS stimulation. In conclusion, our results indicate that GBS survive in macrophages and impairment of PKC signal transduction contributes to their intracellular survival.

Animals↗
PubMed1998

Interferon gamma modifies fibronectin and laminin synthesis in human neuroblastoma cell lines.

Six human neuroblastoma (NB) cell lines of different type: three neuronal, one mixed and two epithelial, were studied for their responsiveness to interferon gamma (IFNgamma). The effects of IFNgamma on cell growth rate and morphology were first evaluated: the replication was significantly inhibited in five out of six NB, while a neural morphological maturation was evident only in the three neural NB. Whether IFNgamma could also control the synthesis of two extracellular matrix glycoproteins, often involved in NB differentiation, laminin (LM) and fibronectin (FN), was then analyzed. Both glycoproteins increased after IFNgamma treatment in all neural and in the mixed NB, while they slightly decreased in one and did not change significantly in the other epithelial NB. Therefore, IFNgamma determines the up-regulation of FN and LM, while inducing NB cell growth inhibition and neural differentiation. These data support the hypothesis that the expression of the two extracellular matrix glycoproteins is controlled by IFNgamma during the complex event of NB terminal maturation.

Fibronectins↗
PubMed1998

The basic residues of placenta growth factor type 2 retrieve sequestered angiogenic factors into a soluble form: implications for tumor angiogenesis.

Placenta growth factor type 1 (PIGF-1) can be synthesized by neoplastic cells in an alternative form (PIGF-2) by the addition of basic amino acids to its classic sequence. Here we show that the basic residues of PIGF-2 compete for the binding of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) to heparan sulfate proteoglycans of the cell surface and extracellular matrix. In doing so, PIGF-2 basic sequences inhibit the sequestering of VEGF and bFGF and maintain them in a highly diffusible form, thus enhancing their angiogenic effect. In agreement with these in vitro data, the presence of PIGF-2 transcripts in tumors correlates with their blood vessel number. These results suggest a mechanism by which growth factor isoforms produced by neoplastic cells enhance the formation of new blood vessels supporting tumor growth and progression.

Angiogenesis Inducing Agents↗
PubMed1998

Local release of interleukin-10 by transfected mouse adenocarcinoma cells exhibits pro- and anti-inflammatory activity and results in a delayed tumor rejection.

Tumor cells engineered to release cytokines are a valuable tool for investigating biological activities elicited by local cytokines. The parental cells of a mouse mammary adenocarcinoma (TSA-pc) were transduced with the cDNA coding for mouse interleukin-10 (IL-10). In vitro, transduced TSA cells secrete about 200 ng of IL-10/10(5) seeded cells in 48 hours (TSA-IL-10). When injected subcutaneously into syngeneic BALB/c mice, TSA-IL-10 cells gave rise to a tumor that grew progressively during the first 7-10 days and then rapidly and completely regressed. To study the events associated with this growth and disappearance, histological, immunohistochemical and ultrastructural analyses of the tumor area were performed at progressive times after challenge. A slow, but progressive and massive recruitment of leukocytes (mainly macrophages and neutrophils) into the tumor was evident. Several CD8+, CD4+ lymphocytes and a few NK cells were present. Marked inhibition of neoangiogenesis was also observed. On day 9, the microvascular network in the growth area had almost vanished, while vascular damage was present in the surrounding stromal tissue. From day 4, down-modulation of VEGF expression in the tumor area and inhibition of tumor necrosis factor-alpha (TNF-alpha) and IL-6 production by reactive leukocytes were evident. The few vessels present in the tumor area displayed poor expression of monocyte chemotactic protein-1 (MCP-1), moderate expression of VCAM-1, and strong expression of ELAM-1, three molecules that result in adhesion of inflammatory cells to the endothelium. A few tumor-infiltrating macrophages were moderately stained with anti-iNOS antibodies. These findings suggest that the collapse of established TSA-IL-10 tumors is the result of the pro- and anti-inflammatory activity of IL-10, which: a) is a signal for the local recruitment of leukocytes; b) leads to vascular damage; c) suppresses cytokine production. The coexistence of both a direct stimulatory activity on endothelial cells and an anti-angiogenic activity is evidence of the ambivalence of the local effects of IL-10.

Adenocarcinoma↗
PubMed1998

Human malignant mesothelioma of the pleura: new perspectives for diagnosis and therapy.

The ability to immortalize human mesothelioma cells in vitro with simian virus (SV) 40 and the fact that SV40 induces mesotheliomas in hamsters prompted us to look for SV40 deoxyribonucleic acid (DNA) sequences in human mesotheliomas. In a previous study, we found that over half (29/48) of human malignant pleural mesotheliomas contained SV40-like sequences whereas only a few (3/47) control samples contained the same detectable sequences. The SV40 genome encodes the 90 KD nuclear large T-antigen (Tag) and the 17 KD small-t antigen (tag), responsible for SV40's transforming and oncogenic properties. These antigens block tumour suppressor gene products, such as p53. We considered the possibility of reverting this effect by adding exogenous wild-type p53 and thus restoring normal cell functions. For this purpose, we developed a recombinant adenovirus carrying complementary DNA (cDNA) for wild type p53 (AdCMV.p53) and infected mesothelioma cell lines with this virus. Inhibition of proliferation, halting of the cell cycle and massive apoptosis was observed in all mesothelioma cell lines tested. In addition, proliferation of human mesothelioma tumours into nude mice was inhibited by in vivo adenovirus-mediated p53 transgene expression. We also report preliminary evidence of expression, by immunoreactivity, of the extracellular matrix protein tenascin in human malignant pleural mesotheliomas. It was interesting to find predominant tenascin positivity at the tumour's invasive edge and in areas of tumour vascularization. This preliminary report suggests that adenovirus-mediated p53 hyperexpression counteracts transforming properties of the large T-antigen and suggests that gene therapy may be useful in treating human malignant mesothelioma.

Animals↗
PubMed1998

SV40 expression in human neoplastic and non-neoplastic tissues: perspectives on diagnosis, prognosis and therapy of human malignant mesothelioma.

We have recently demonstrated the association of SV40 and human pleural malignant mesothelioma. Here, we have investigated whether SV40 viral sequences may be associated with other human tumours or other non-neoplastic pathology and whether SV40 DNA or protein expression may be of diagnostic, prognostic or therapeutic relevance. DNA was extracted from paraffin embedded tissues. SV40, JC and BK viral sequences were detected by the polymerase chain reaction and molecular hybridization with specific probes. The screening with three different sets of SV40-related primers demonstrated that 7/18 (38.8%) mesothelioma specimens were SV40 positive as well as 5/18 (27.7%) tubercular pleural lesions. None of the 18 lung cancers, nor the 20 pleural non-specific inflammatory specimens tested were positive. Twenty-five blood samples and 18 urinary sediments from MM patients were also negative. We have also found that SV40 Tag proteins are present in mesothelioma cells and tumours. Tag proteins may interfere with tumour suppressor gene products, such as p53. Preliminary results suggest that wild type p53 transgene expression, obtained after infection with recombinant adenovirus (AdCMV.p53), inhibited in vitro and in vivo proliferation, inducing apoptosis of mesothelioma cells. Infections with control viruses were ineffective. Thus, SV40 DNA and Tag expression in mesothelioma tumour cells, though probably not relevant for diagnostic or prognostic purposes, may be crucial for innovative gene therapy strategies.

DNA, Viral↗
PubMed1998

Effect of acute increase of interstitial myocardial fluid on ventricular function in isolated working rat hearts.

An acute increase of myocardial interstitial fluid may affect ventricular function. In the present study we evaluated the effects of acute changes of myocardial tissue fluid on cardiac function and ultrastructural morphometry. Isolated rat hearts were perfused for 100 min in the working heart mode. Hearts were distributed into 5 groups: controls [perfused with Krebs-Henseleit (KH) isotonic buffer to rat plasma, KH, 287 mOsm], moderate hyposmotic perfusion (75% Hyposm: perfusion with 75% diluted KH, 216 mOsm), highly hyposmotic perfusion (60% Hyposm: perfusion with 60% diluted KH, 170 mOsm), afterload increase (Pre-over: isotonic perfused hearts subjected to an increase of afterload from 72 to 145 cm H2O) and ion dilution (Ion-dil: hearts perfused with a 60% KH with 115 mM sucrose, isotonic, 287 mOsm). We evaluated functional changes, markers of cellular necrosis or damage (CPK, LDH and purine release in coronary effluent), heart weight changes (weight gain and ww/dw ratio) and ultrastructural morphometry (analysis of cell damage, interstitial area, and mitochondrial alterations by a computerized image analysis system). The ww/dw ratio increased significantly only in 60% Hyposm (+140%, p < 0.001) and Pre-over (+63%, p < 0.001 vs control) groups. An impaired myocardial function in 60% Hyposm, Pre-over and Ion-dil groups was observed with cardiac failure at 50, 60 and 60 min, respectively. Enzyme release was significant higher in 60% Hyposm and Pre-over groups and was related to heart weight gain (r = 0.85, p < 0.001). Ultrastructural analysis confirmed a significant increase of interstitial space area (ISA) and mitochondrial damage in 60% Hyposm and Pre-over groups (p < 0.001); a significant (p < 0.05) increase was observed in the Ion-dil group; in 75% Hyposm group, a significant increase of mitochondrial damage was detected (p < 0.05). In brief, a higher functional and morphological deterioration was observed in hearts in which a more evident interstitial edema was detected (60% Hyposm and Pre-over groups). We conclude that, in the experimental condition, an acute increase of myocardial interstitial tissue fluid directly compromises left ventricular function and contributes to the ultrastructural damage to the myocardium.

Animals↗