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E Tabone

Publications and source records attributed to E Tabone.

At least 19 recordsLinked to original sources
PubMed1996

Cellular distribution of EGF, TGFalpha and their receptor during postnatal development and spermatogenesis of the boar testis.

The epidermal growth factor (EGF), the transforming growth factor alpha (TGFalpha) and the epidermal growth factor receptor (EGFr) have been immunolocalized, (i) during the testicular postnatal development (i.e. at the perinatal, prepubertal and adult periods), and (ii) during the seminiferous epithelium cycle in the different germ cell types. While TGFalpha was essentially observed in somatic cells, specifically in perinatal Leydig cells and in mature Sertoli cells, EGF was localized both in germ cells and in somatic cells with a preferential tubular expression. Furthermore, identification of EGFr in different testicular cell types indicates that during postnatal development and spermatogenesis, testicular cells are potentially responsive to EGF in that they express EGFr. Indeed, in the course of the gonadal development, the EGFr distribution was evidenced both in somatic and germ cells with a specific germ cell pattern depending upon the seminiferous epithelium cycle. A predominant EGFr staining was evidenced during the meiotic process and the spermiogenesis. Together, the present data are in favor of the involvement of the TGFalpha/EGF system in the local control of testicular cells during development and particularly of its potential direct implication in crucial steps of spermatogenesis such as meiosis and spermiogenesis.

Aging↗
PubMed1996

Sertoli cells as potential targets of prolactin action in the testis.

Using primary cultures of porcine Sertoli cells as a model, the effects of ovine prolactin (oPRL) on Sertoli cell function were investigated through FSH binding. PRL treatment (0.3-5 ng/ml) induced a dose-dependent increase (ED50 = 5.10(-11) M) of 125I-FSH binding to Sertoli cells to a maximal stimulation (about 2.5-fold increase). This effect was time-dependent, being detected within 2 h (P < 0.02) after oPRL treatment and was maximal after 24 h. The effect of oPRL is probably mediated via specific PRL receptors identified by different approaches such as immunohistochemistry, binding assays and cross-linking experiments. Immunohistochemical experiments were performed using two antibodies directed against the PRL receptor. Immunoreactivity was detected both in the Sertoli cell cytoplasm and in the perinuclear area. Scatchard plots of binding studies revealed the presence of specific binding sites for PRL both in the Sertoli cell membranes and nuclear fractions with high affinity constants (Kd = 0.8 and 1.4 nM, respectively). Affinity labeling of these receptors by covalently binding to 125I-oPRL and subsequent electrophoretic analysis of the labeled complexes revealed for the cell membranes, two major labeled bands of 74 and 64 kDa and three other faintly labeled bands of 190, 150 and 140 kDa. For the nuclear fractions, three major labeled bands with high molecular weights of 190, 150 and 140 kDa were observed. Taken together, the present findings suggest that Sertoli cells are potential targets for prolactin action in the porcine testis.

Animals↗
PubMed1995

Tumor induction by v-Jun homodimers in chickens.

To study the contribution of v-Jun homodimers to oncogenesis, we constructed artificial v-Jun derivatives in which the natural dimerization domain of v-Jun was replaced by an heterologous homodimerization domain from either the viral EB1 or the yeast GCN4 transcription factor. The resulting v-Jun chimeric proteins, called v-Juneb1 and v-Jungcn4, which can no longer dimerize with Jun or Fos, should only form homodimers in the cell. Helper-independent retroviruses expressing v-Jun, v-Juneb1 and v-Jungcn4 were generated. All three viruses transformed primary cultures of chick embryo cells with the same high efficiency and promoted local tumor growth after subcutaneous injection of infected cells in young animals. In contrast, after intravenous injection of viral suspensions into chick embryos, only the chimeric proteins produced internal tumors that were lethal. These tumors were leiomyosarcomas located within the liver and along the digestive tract. Thus, in vivo, v-Juneb1 and v-Jungcn4 are more potent oncoproteins than v-Jun. These data demonstrate that when forced to accumulate, v-Jun homodimers can induce tumors efficiently. They also show that the oncogenic potential of v-Jun can be regulated through the properties of its dimerization domain.

Animals↗
PubMed1995

Thrombospondin modulates melanoma--platelet interactions and melanoma tumour cell growth in vivo.

In this study we have investigated the role of thrombospondin (TSP) as a possible ligand playing a key role in human M3Da. melanoma cell interaction with platelets and in tumour growth. TSP is secreted (80 +/- 6 ng TSP 10(-6) cells) and bound to the surface of M3Da. cells via receptors different from CD36, as shown by biosynthetic labelling and immunofluorescence studies. The levels of TSP binding to M3Da. cells evaluated by binding studies, using an anti-TSP monoclonal antibody (MAb) (LYP8), shows 367,000 +/- 58,000 (mean +/- s.d.) LYP8 binding sites per cell with a dissociation constant (Kd) of 67 nM. TSP binding to M3Da. cells shows 400,000 +/- 50,000 TSP binding sites per cell with a Kd of 10 nM. The capacity of anti-TSP MAb (LYP8) to inhibit M3Da.-platelet interactions was followed on an aggregometer and evaluated by electron microscopy studies. The biological role of TSP binding to M3Da. cells was investigated by implanting subcutaneously the M3Da. cell line in nude mice and following the size and time of in vivo tumour growth. Reducing the availability or the functional level of TSP by using an anti-TSP MAb (LYP8) resulted in a significant decrease in platelet aggregates interacting with M3Da. melanoma cells. Using an enzyme-linked immunosorbent assay, purified alpha nu beta 3 was shown to bind TSP. Moreover, LYP8-coated M3Da. cells showed a reduced capacity to form tumours in vivo. M3Da. cells were observed to attach and spread on human platelet TSP-coated plastic wells. This attachment by M3Da. cells was inhibited in a similar way by LYP8 and an anti-alpha nu beta 3 MAb (LYP18). The results obtained in this study show that TSP secreted and bound to the surface of a human melanoma cell line (M3Da.) acts as a link between aggregated platelets and the M3Da. cell surface. Moreover, these results shows that TSP can modulate tumour growth in vivo. Reagents such as MAbs directed against TSP and peptides derived from TSP could not only be used as a new therapeutic approach in the control of tumour metastasis of melanoma, but may also contribute to elucidation of the role of TSP in cancer biology.

Animals↗
PubMed1995

Immunolocalization of transforming growth factor-beta 1 and transforming growth factor-beta 2 in the mouse ovary during gonadotrophin-induced follicular maturation.

An immunohistochemical approach was utilized to evaluate the cellular distribution of transforming growth factor-beta 1 (TGF beta 1) and transforming growth factor beta 2 (TGF beta 2) at different stages of follicle development in the prepubertal mouse ovary under the following conditions: (i) after pregnant mare's serum gonadotrophin (PMSG) treatment; (ii) after PMSG and human chorionic gonadotrophin (HCG) treatment; (iii) after PMSG and HCG treatment plus mating. In the immature ovary, TGF beta 1 and TGF beta 2 immunoreactivities are localized in theca and granulosa cells and in oocytes. After PMSG treatment, TGF beta 1 and TGF beta 2 immunoreactivities are localized in granulosa cells; in addition, TGF beta 2 staining is noted in the matrix surrounding antral cells. Staining for both TGR beta 1 and TGF beta 2 drops in the theca but persists in the oocyte. PMSG plus HCG treatment results in a significant increase in TGF beta 1 and TGF beta 2 immunoreactivity in the theca and in the maintenance of TGF beta 1 staining in both basal granulosa cells and cumulus cells whereas TGF beta 2 immunoreactivity is essentially localized in the matrix surrounding cumulus cells. Staining for TGF beta 1 and TGF beta 2 persists in the oocyte. Following PMSG plus HCG treatment and mating, TGF beta 1 immunoreactivity is localized in the luteal cells of corpora lutea and TGF beta 2 shows a similar localization pattern. This study provides evidence that TGF beta 1 and TGF beta 2 peptides are expressed in specific cell types during induced follicular maturation in the mouse ovary.

Animals↗
PubMed1995

[A new biomaterial in surgery of ptosis with frontalis suspension: wide pore PTFE].

BACKGROUND: In brow suspension, there is agreement that fresh tissue (autogenous fascia lata or temporalis fascia) provides the best results in terms of low complications and duration of the effect. Yet, the morbidity of fresh tissue harvesting is not negligible. Many alternative materials have disadvantages in terms of duration of the procedure and side effects. METHODS: We have used a new material: wide porous expanded polytetrafluoroethylene (eP.T.F.E.). This material is an inert vitreous teflon alloplast with a high biocompatibility. It is close to Gore-Tex, but differs from it by a higher porosity (over 90%) and wider diameter of its pores (over 50 mus). We performed a series of 60 brow suspension from February 1992 to March 1994, using this new material. RESULTS: We did not encounter any significant complications due to the material and in circumstance, we did not deplore any migration, infection or extrusion of the ePTFE. The biocompatibility seems to be increased, as it has been demonstrated by light and electron microscopy of the implanted material who revealed that fibrovascular ingrowth was significantly achieve two months after surgery. CONCLUSION: The first results of this series are very encouraging. They can favourably be compared with the results of other series using different types of materials available in brow suspension. Though our longest follow-up is 30 months, further study is necessary to evaluate the long term results and eventual long term side effects of ePTFE, which avoid harvesting fresh tissues, thus reducing the brow suspension procedure's morbidity.

Adolescent↗
PubMed1994

Hepatocarcinoma-specific mutant p53-249ser induces mitotic activity but has no effect on transforming growth factor beta 1-mediated apoptosis.

Mutations affecting the p53 gene abrogate its tumor suppressor activity. It is, however, unclear whether such mutations can generate mutant p53 proteins with an intrinsic transforming ability. More importantly, the mechanism(s) by which they exert such activity is unknown. We report here that p53-deficient hepatoma cells (Hep3B) transfected with mutant p53-249ser (codon 249 Arg-->Ser) acquire a new phenotype with an increased in vitro survival and mitotic activity. However, such a phenotypic change is not sufficient to cause a major shift in the poor tumorigenic potential of these cells. This is apparently due to transforming growth factor beta 1-mediated apoptotic death of Hep3B cells which is not affected by the expression of p53-249ser.

Amino Acid Sequence↗
PubMed1994

Desmoplastic small round cell tumors of the abdomen.

BACKGROUND: Desmoplastic small round cell tumors (DSRCT) have been only recently identified. METHODS: The authors report DSRCT in two pediatric patients (an 8-year-old boy and 12-year-old boy). In both patients, the initial diagnosis was rhabdomyosarcoma. The resistance to standard chemotherapy and radiation therapy prompted the authors to review the initial biopsy specimens and perform complementary immunophenotypic characterization. RESULTS: These analyses revealed that the tumor cells were strongly positive for keratin epithelial marker antigen, desmin, vimentin, neurospecific enolase, and S100 protein, corresponding to pleomorphic differentiation, characteristic of DSRCT: CONCLUSIONS: The authors suggest that extensive immunohistologic characterization be performed in all cases of small round cell tumors of the abdomen so that the diagnosis of DSRCT is not overlooked. These rare tumors are refractory to chemotherapy, and initial aggressive surgery is warranted.

Antigens, Neoplasm↗
PubMed1994

Human melanoma cell lines differ in their capacity to release ADP and aggregate platelets.

In this study we have investigated, using three different human melanoma cell lines (M1Do., M3Da., M4Be.). the varying capacity of melanoma cells to induce platelet aggregation in the presence or absence of inhibitors of ADP or thrombin. The expression levels of different integrins (alpha v, beta 3, alpha v beta 3, alpha IIb, alpha v beta 3) were evaluated by immunoprecipitation, binding and flow cytometry studies. The level of ADP in supernatants of melanoma cells were quantified by ADP bioassay and HPLC. Platelets were irreversibly aggregated by M3Da, as shown by electron microscopy, in contrast to M1Do, which induced a slow reversible aggregation. M4Be. did not induce platelet aggregation. In both cases, with M3Da. or M1Do., apyrase but not PPACK inhibited platelet induced aggregation. An anti-alpha v beta 3 monoclonal antibody (LYP18) or polyclonal antibody inhibited platelet aggregation. A similar number of LYP18 molecules bound to the surface of M1Do., M3Da. and M4Be. cell lines. Biological HPLC assays of ADP present in the supernatant of tumour cell lines showed the highest concentration of ADP to be secreted by M3Da., followed by M1Do., and none detected for M4Be. These results show that differences in in vitro aggregating potential of the three human melanoma cell lines are not related to low integrin expression levels but to their ability to generate ADP. Generation of ADP by human melanoma cells may act as important modulator of melanoma-platelet interactions.

Adenosine Diphosphate↗
PubMed1993

[Giant cell fibroblastoma. Apropos of 2 cases].

Two cases of giant cell fibroblastoma (GCF) are reported. One presented as cervical tumor in a 11 year old child and the second localized in axillar region of 14 year old boy. Histologically both showed a typical distinctive appearance of this entity when focal fusocellular cells arranged in a storiform pattern was also constated in one. The immunohistochemical and ultrastructural study ruled out a vascular origin. The clinical and pathological findings suggest that CGF represent a juvenile form of dermatofibrosarcoma protuberans.

Adolescent↗
PubMed1991

Expression of integrin receptors on 45 clinical neuroblastoma specimens.

Immunohistological expression of integrins has been analyzed on 45 neuroblastoma specimens representative of the different clinical and histological forms of the tumor. None of the specimens expressed the alpha 5 chain of the integrins. The beta 1 chain was expressed on all specimens, the alpha 1 chain on 44 specimens and the alpha 3 chain on 42; the 4 specimens which lacked alpha 1 or alpha 3 were stage-4 neuroblastomas. The alpha 2 chain was expressed on 18 specimens, and the alpha 6 chain on 17; 15 reacted with both. Their reactivity was related to the maturation of the tumor rather than the stage of the disease: they were expressed on low-grade, well-differentiated specimens; stage 3-4 neuroblastoma specimens analyzed at diagnosis were negative, but usually expressed both chains when analyzed after in vivo differentiation by chemotherapy. alpha v reacted with 18 specimens and beta 3 with 12, without strict relation with the stage of the disease and/or its degree of differentiation; 9 well-differentiated specimens expressed the beta 4 chain; only 4 well-differentiated specimens expressed the alpha 4 chain. The 4 specimens which lacked alpha 1-beta 1 or alpha 3-beta 1 expression had n-myc amplification, whereas those which expressed either alpha 4, beta 4, beta 3 or alpha v had no amplification. Furthermore, the expression of the 3 heterodimers alpha 4-beta 1, alpha v-beta 3 and alpha 6-beta 4 was essentially observed on primary tumors which developed in the mediastinum. The expression of alpha 2-beta 1 and alpha 6-beta 1 was observed on both n-myc-positive and -negative specimens. beta 1 and alpha 3 were diffusely expressed on all counterparts of these tumors, from undifferentiated neuroblasts to ganglion and Schwann cells. The alpha 1 chain reacted with undifferentiated and intermediate neuroblasts as well as with Schwann cells, but ganglion cells were negative. alpha 2 and alpha 6 chains were negative on undifferentiated neuroblasts, variably expressed on intermediate neuroblasts, and restricted to Schwann cells in ganglioneuroma. The expression of alpha 4 and beta 4 was restricted to Schwann cells. alpha v and beta 3 occasionally reacted with undifferentiated and intermediate neuroblasts; alpha v was strongly positive on Schwann cells but negative on ganglion cells, whereas beta 3 was positive on both neuronal and non-neuronal populations.

Ganglioneuroma↗
PubMed1991

Expression of leucocyte adhesion molecules on 66 clinical neuroblastoma specimens.

LFA-3, ICAM-1, HLA.ABC and HLA.DR expression was analyzed on 66 neuroblastoma specimens. HLA.ABC was expressed on 26 specimens, HLA.DR on 2, LFA-3 on 20 and ICAM-1 on 10. HLA.ABC and LFA-3 were positive on ganglioneuroblastoma or ganglioneuroma, but they were negative on neuroblastoma, independently of the clinical staging; HLA.ABC and LFA-3 were induced in vivo by chemotherapy in parallel with tumoral cell differentiation, in both the primary and the metastases. The expression of ICAM-1 was restricted to 5 of the 10 low-grade stage-1 or stage-2 specimens, 1 stage-3 specimen, and the primary tumors of 2 patients with stage-4 disease, analyzed hence at diagnosis and after chemotherapy (4 specimens); metastatic cells obtained in 1 of these patients were negative. HLA.ABC and LFA-3 expressed on both mycN-negative and -positive specimens, whereas ICAM-1 was restricted to MYCN-negative specimens. LFA-3 diffusely stained partially differentiated neuroblasts, Schwann cells and ganglion cells. The expression of HLA.ABC on differentiated neuroblasts varied from one sample to another and within the same tumor; Schwann cells were strongly positive, but ganglion cells were negative. In positive samples, ICAM-1 was expressed on differentiated neuroblasts and Schwann cells, but negative on ganglion cells; however, most of the differentiated tumors were ICAM-1-negative, suggesting ICAM-1 induction by unknown local signal. The 4 markers were negative on undifferentiated neuroblasts. The distribution of these 4 markers on clinical specimens was in agreement with their reactivity on fetal tissues, as well as with results obtained on neuroblastoma cell lines before and after in vitro treatment with IFN-gamma.

Alkaline Phosphatase↗
PubMed1991

Alteration of the inner surface of venous catheters by antineoplastic drugs.

Septic complications and thrombosis are frequent causes of long-term venous catheter implantation failure and tend to occur more frequently in oncology than in patients using catheters for hyperalimentation only. The purpose of this in vitro study was to study extensively the inner surface behaviour and the possible changes in their mechanical properties of various silicone and polyurethane catheters after exposure to a flow of the most common antineoplastic drugs. Silicone catheters appeared to be the best choice for cytostatic drug infusions because of their chemical stability, but the addition of an opacifier imposes a protective inner and outer layer to improve their surface properties for biocompatibility.

Antineoplastic Agents↗
PubMed1991

Immunolocalization of transforming growth factor-beta 1 in the bovine adrenal cortex using antipeptide antibodies.

Eight- to 12-amino acid long peptides, representing fragments of transforming growth factor-beta 1 (TGF beta 1) and TGF beta 2 were selected on the basis of their potential immunogenicity and were used to generate polyclonal antibodies. Anti-TGF beta 1-(91-103) antibodies recognized specifically TGF beta 1, prevented TGF beta 1 binding to NRK-49F cells, and neutralized the biological activity of TGF beta 1 in adrenocortical cells (consisting in the inhibition of angiotensin-II-induced cortisol production). Antibodies raised against TGF beta 2-(65-73) appeared to recognize TGF beta 2 with a better affinity than TGF beta 1, but were unable to block the binding of either TGF beta 1 or TGF beta 2 to their receptors or to inhibit their biological activity. These observations are in line with a prominant role of the C-terminal domain of TGF beta 1 in its interaction with its receptor(s) and, hence, in its biological activity. Using anti-TGF beta 1-(91-103) antibodies, we could localize immunoreactive TGF beta 1-like material in the cortex of adult bovine adrenal glands. No reactivity was detected in the capsule or adrenal medulla. The reactivity was maximal in the zona fasciculata/reticularis and weaker in the zona glomerulosa. TGF beta-like material was present in a latent form in the conditioned medium from primary cultures of bovine adrenocortical cells. These cells secreted about 5 ng heat-activatable TGF beta-like material/24 h of culture.10(6) cells. Taken together with our previous reports that bovine adrenocortical cells possess high affinity TGF beta 1 receptors and secrete a TGF beta 1-like molecule under a latent form, the present observations further support the hypothesis that TGF beta 1 or a closely immunologically related protein acts as an autocrine regulator of adrenocortical steroidogenic functions.

Adrenal Cortex↗
PubMed1991

Extracellular matrix and intermediate filaments in the first stages and repair of experimental gingivitis in man.

By the indirect immunoperoxidase labelling procedure the expressions of type I and III collagens, laminin and fibronectin and of KL1 cytokeratin and vimentin were examined in the first stages and repair of experimental gingivitis in young subjects. A two month longitudinal study was performed using the tissue from buccal marginal gingival biopsies of four subjects taken sequentially at five specific times: before and during plaque accumulation, and during plaque elimination. The sites examined microscopically were the coronal half of the junctional epithelium and the underlining infiltrated connective tissue fraction. No clinical change could be observed during the study period. Histological examination showed reversible cellular changes during the accumulation of plaque. There were increases in vascularization and cellularity and loss of collagen. They recovered 56 days after plaque elimination their baseline level. Electron microscopic examination showed myofibroblastic aspects in some fibroblasts. The changes in the expression of laminin, fibronectin and KL1 in the J.E. might be due to a proliferation rate enhancement, and suggest an adaptation to the alterations brought about by the inflammatory process. They also reinforce the hypothesis that this epithelium resembles a developmental tissue. Type I collagen demonstrated the "collagen loss-repair" cycle shown in connective tissue by the histological study. The rise in type III collagen and the vimentin fall, both at the initial stage, suggest that these protein profiles may yield information for clinical research purposes during the very early inflammatory process. The variations in fibronectin indicate its key role in the early inflammatory and repair processes. Finally, the variations in matrix and cytoskeletal proteins variations, as well as the morphological modifications observed, were nearly all reversible.

Adolescent↗
PubMed1989

Platelet-melanoma cell interaction is mediated by the glycoprotein IIb-IIIa complex.

A human malignant melanoma cell line (M3Dau) was observed by electron microscopy to interact directly with human platelets and induced platelet aggregation. Fab fragments of a monoclonal antibody MoAb (LYP18), directed against the platelet glycoprotein (GP) IIb-IIIa complex, inhibited platelet-melanoma interactions and platelet-platelet aggregation. M3Dau melanoma cells bind LYP 18 and synthesize IIb-IIIa-like GPs. When the melanoma cells were preincubated with LYP 18, tumor-platelet interaction did not occur, suggesting that the interaction may be mediated by the IIb-IIIa-like GPs present on the melanoma cell surface. Glanzmann's thrombasthenic platelets, lacking GPIIb and IIIa, did not interact with melanoma cells, indicating that the platelet GPIIb-IIIa complex is also necessary for the platelet-melanoma cell interaction. This work demonstrates the importance of the IIb-IIIa-like GPs, present on M3Dau melanoma cells, in mediating tumor-platelet interactions.

Antibodies, Monoclonal↗