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Biomedical subjects

G Manzo

Publications and source records attributed to G Manzo.

At least 19 recordsLinked to original sources
PubMed2001

Cancer genesis: stem tumour cells as an MHC-null/HSP70 - very high 'primordial self' escaping both MHC-restricted and MHC-non- restricted immunesurveillance.

I have previously assumed that in tumours there are stem cells, that owing to the morphophysiologic properties shared with embryonal cells I have defined as 'para-embryonal' cells (PECs). Owing to a blocking mutation, PECs might be able to express only the genic program upstream from the block, but not that downstream. As a consequence, PECs might lack in genic differentiated products, such as MHC molecules, and might be very rich in primitive genic products, such as HSP70 molecules. Like embryonal cells, PECs might carry out induction on adjoining hyperplastic cells, thus transforming them, only phenotypically, into 'differentiated para-embryonal cells' (DPECs), endowed with both MHC and HSP70 molecules. In such a way, nuclei of MHC-non-expressing/HSP70-high expressing stem tumour cells might be surrounded by layers of MHC-expressing/HSP70-expressing non-stem tumour cells. Such a structural tumour organization, actually found by C. Cordon Cardo et al. with regard to the MHC molecule expression, might be responsible for interference phenomena versus the MHC-non-restricted immune cells, such as macrophages and NK cells. So, these cells, the only potentially able to recognize and eliminate MHC-non-expressing stem tumour cells (PECs), might spare them, thus rendering cancer a biological process without any natural immunological solution. Now, I would like to theorically demonstrate that cancer might be a process without immunological solution from the very beginning: the first stem tumour cell might be tolerated as a sort of 'primordial self' because of its MHC-null/HSP70-very high phenotype, recognizable by neither the MHC-restricted nor the MHC-non-restricted immunesurveillance systems of the host. Possible biological roles of HSP70 molecules might account for the immunesurveillance escape of stem tumour cells. Existence of these cells appears to be confirmed by the recent experiments of immunotherapy with autologous tumour-specific HSPs carried out by P. K. Srivastava; moreover, their 'self' nature appears to be confirmed by the most recent experiments of compatible bone marrow allograft carried out by A. M. Carella. On this ground, the main steps for a resolutive antitumour immunotherapy are proposed.

HSP70 Heat-Shock Proteins↗
PubMed1999

Comparison of losartan and hydrochlorothiazide on cognitive function and quality of life in hypertensive patients.

We examined long-term changes in cognitive function and quality of life (QL) in hypertensive patients by comparing the antihypertensive effect of hydrochlorothiazide (HCTZ) and losartan. We studied 69 patients (age range, 30 to 73 years) with mild-to-moderate hypertension. All patients, in a double-blind study, were randomly allocated to either treatment with 50 mg losartan once daily or 25 mg HCTZ once daily. The sample in each treatment group was divided by age (younger than 60 years or 60 years or older). At baseline and after 26 months, a QL questionnaire appropriate for the hypertensive patients was given. Cognitive function was evaluated, at baseline and after 26 months, by psychometric tests consisting of items from the Mini-Mental State Examination (MMSE) and the Sandoz Clinical Assessment Geriatric (SCAG). A score of less than 24 on the MMSE and more than 40 on the SCAG was predictive of cognitive impairment. The losartan group had a significant improvement in SCAG (P<.001) and MMSE (P<.001). No significant changes were observed in the HCTZ group (SCAG, P = .1; MMSE, P = .2). Sixty-five percent of the elderly had a MMSE score less than 24 and 70% had a SCAG score greater than 40, v. 35% and 48%, respectively, in younger patients. The health state index of QL improved significantly in both groups (losartan group, P<.01; HCTZ group, P<.02); the improvement in QL scores in patients using HCTZ was significant only in subjects aged 60 years and older (P<.04). These results suggest that losartan can have a positive effect not only on blood pressure but also on impaired cognitive function, reversing even minimal cognitive deficits induced by hypertension. The elderly patients in our sample had worse scores and cognitive performance was lower than in younger patients, even if in the losartan group the score improvement was the same at all ages. The same could not be said for HCTZ.

Adult↗
PubMed1999

Regulation of thymosin beta10 expression by TSH and other mitogenic signals in the thyroid gland and in cultured thyrocytes.

OBJECTIVE: To investigate the expression of thymosin beta10 - a small conserved acidic protein involved in the inhibition of actin polymerization - in human and experimental thyroid goiters as well as the regulation exerted by TSH on thymosin beta10 expression in thyroid follicular cells both in vivo and in vitro. DESIGN: To this aim, we have used 5 bioptic specimens from patients affected by thyroid goiter, a well known experimental model of thyroid goitrogenesis (rat fed with the drug propylthiouracil) and a cultured rat thyroid cell line (PC Cl 3 cells) as a model system. RESULTS: We report that the mRNA expression of thymosin beta10 is markedly enhanced in human goiters compared with normal thyroid. In vivo results showed that the steady-state level of thymosin beta10 mRNA is up-regulated in the thyroid gland of propylthiouracil-fed rats in parallel with follicular cell proliferation: iodide administration to goitrous rats, which induced a marked involution of thyroid hyperplasia, reduced the mRNA level of thymosin beta10. Finally, in vitro studies showed that in cultured rat thyrocytes, the expression of thymosin beta10 mRNA is induced in a time- and dose-dependent manner by the activation of pathways which are mitogenic for thyroid cells (i.e. the protein kinase (PK) A and PKC pathways). CONCLUSION: Taken together, the findings reported here demonstrate that thymosin beta10 expression is regulated by extracellular signals that stimulate growth of thyroid cells both in vitro and in vivo, and suggest a role for this protein in thyroid diseases characterized by proliferation of follicular cells.

Animals↗
PubMed1998

The cancer process as a type of immunocomplex hypersensibility involving C3b, natural killer cytotoxicity and antibody-dependent cell cytotoxicity: proposals for tumour immunotherapy and vaccine.

I have previously assumed that stem tumour cells are 'para-embryonal cells' (PECs) poor or missing in major histocompatibility complex (MHC) antigens. PECs might induce adjoining differentiated hyperplastic cells to also express tumoral phenotype and properties, thus transforming them into 'differentiated para-embryonal cells' (DPECs), MHC-endowed. In such a way, PECs, MHC-lacking, would be automatically surrounded by DPECs, MHC-endowed: this tumour organization was experimentally found by Cordon-Cardo et al in a variety of cancers. Now, I suggest that such a tumour histology might preferentially induce an anti-DPEC T cell immune response which, sparing PECs, might release increasing amounts of DPEC antigens in the peritumour site. DPEC antigens might increase synthesis of specific antibodies and subsequent immunocomplex formation at the peritumour site. Here, abundant immunocomplexes might react through their Fc pieces with CD16 receptors of antibody-dependent cell cytotoxicity (ADCC)-endowed immune cells (natural killer (NK) cells, macrophages, polymorphonuclear cells). These cells would thus be stimulated to secrete their lytic factors before and without their coming into contact with target tumour cells. On the other hand, abundant immunocomplexes at the peritumour site might massively activate the complement system, thus generating large amounts of C3b. C3b might react with CD11b receptors of NK cells, stimulating them to also secrete their lytic factors in an ectopic way at the peritumour site, thus impairing NK cytotoxicity. In such a way, in the absence of ADCC and NK cytotoxicity, a tumour cell enhancement might easily occur. In the light of these ideas, a strategy for antitumour immunotherapy and vaccine is then proposed.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1998

Natural killer cell reactivity: activation and cytolysis mechanism models, involving heat shock protein, haemopoietic histocompatibility, major histocompatibility complex and complement molecules.

The close association of heat shock protein (HSP), haemopoietic histocompatibility (Hh), major histocompatibility complex (MHC), and complement genes on the same chromosomal region, and the fact that all these genes are inherited on the whole in each haplotype of an individual, might indicate some evolutionary and functional correlations among them. Several data suggest for HSP70 molecules a possible role as a molecular target recognizable by natural killer (NK) cells. HSP70 sequences from both prokaryotic and eukaryotic organisms reveal that about half of the amino acid residues are identical and many of the remaining residues are similar. I here assume that NK reactivity might start, early in the immunogenesis process, as a effect of the interaction between HSP70 molecules and a hypothetical HSP receptor of yet immature non-cytolytic NK cells. To this receptor, an HSP molecule might act as an activator or an inhibitor depending on whether its amino acid residues are reactive or not with it, respectively. Later in the immunogenesis process, murine Hh or human equivalent molecules, dominantly expressed in bone marrow target cells, might select the non-reactive NK clones of an individual, inducing them to mature and express a lytic machinery. As a consequence of the NK maturation, proliferating hemopoietic target cells expressing only or mainly activator HSPs on their surface might undergo NK cytolysis. This might explain the NK lysis of apparently normal cells found in human foetal marrow; moreover, this might explain in some way the F1 hybrid resistance phenomenon. The NK reactivity of an individual would be further modulated by the expression on the NK surface of particular receptors (CD94, p58) specific for defined MHC molecules (Cw1, Cw3, Bw6, B7) on the target cells. Such a specific interaction would induce an 'NK effector inhibition'. The NK reactivity mechanism might have been further evolutionarily modified and adapted by the involvement of other NK receptors, such as CD11b (specific for the C3b factor of the complement) and CD16 (specific for the IgG Fc piece). Cooperation among HSP, MHC, CD11b, CD16, C3b and Fc allows us to propose original models of the activation and cytolysis mechanisms in the NK cytotoxicity and antibody-dependent cell cytotoxicity phenomena.

Animals↗
PubMed1997

Upregulation of the angiogenic factors PlGF, VEGF and their receptors (Flt-1, Flk-1/KDR) by TSH in cultured thyrocytes and in the thyroid gland of thiouracil-fed rats suggest a TSH-dependent paracrine mechanism for goiter hypervascularization.

Placenta growth factor (PlGF) and vascular endothelial growth factor (VEGF) represent two closely related angiogenic growth factors active as homodimers or heterodimers. Since goiters of the thyroid gland are extremely hypervascular, we investigated the expression of PlGF, VEGF and their receptors, Flt-1 and Flk-1/KDR, in a small panel of human goiters from patients with Graves's disease, in an animal model of thyroid goitrogenesis and in in vitro cultured thyroid cells. Here we report that the mRNA expression of PlGF, VEGF and their receptors is markedly enhanced in biopsies of goiters resected from Graves's patients. In vivo studies demonstrated that in the thyroid gland of thiouracil-fed rats, increased mRNA and protein expression of PIGF, VEGF, Flt-1 and Flk-1/KDR occurred subsequent to the rise in the serum thyroid stimulating hormone (TSH) levels and in parallel with thyroid capillary proliferation. In vitro studies confirmed the existence of such TSH-dependent paracrine communication between thyroid epithelial cells and endothelium since the conditioned medium collected from TSH-stimulated thyrocytes acquired mitogenic activity for human umbilical vein endothelial (HUVE) cells. Altogether, these data suggest that PlGF and VEGF, released by thyrocytes in response to the chronic activation of the TSH receptor pathway, may act through a paracrine mechanism on thyroid endothelium.

Animals↗
PubMed1996

Neovascularization in human germ cell tumors correlates with a marked increase in the expression of the vascular endothelial growth factor but not the placenta-derived growth factor.

Neoangiogenesis is a prerequisite for tumor growth and metastasis. In germ cell cancer patients with the disease limited to the testicle (stage A), tumor-associated neovascularization is predictive of metastatic disease (stage B). To investigate the molecular mechanisms underlying neovascularization in human germ cell tumors (GCTs), we analysed the expression of two angiogenic growth factors, vascular endothelial growth factor (VEGF) and placenta growth factor (P1GF), and of their receptors (FLT-1) and Flk-1/KDR) in a panel of testicular tumors. In this study we show a marked increase in VEGF expression in 36/44 (81.8%) primary testicular-derived GCTs, as compared to normal testis, that significantly correlates with a high density of intratumor microvessels (r = 0.72461, P < 0.001; n = 24). As determined by RT - PCR and/or Western blot, the predominant VEGF isoforms expressed in GCTs are the VEGF121 and VEGF165, which are more efficiently secreted by the cells, and thus more active in eliciting angiogenesis. Conversely, in the case of PIGF, only a weak correlation with the vascular density of tumors is observed (r = 0.26599, P < 0.05; n = 24). Northern blot analysis also revealed significant up-regulation of VEGF/ PIGF receptors in highly vascularized germ cell tumors, compared to normal testes. These findings suggest that VEGF may act in a paracrine manner to induce neovascularization, oedema extravasation and cyst formation in human germ cell tumors. The correlation between VEGF expression and the vascular density of tumors, suggest that the evaluation of VEGF expression may be of help in predicting patients at risk for metastatic diseases. Finally, we demonstrate that VEGF up-regulation may occur at the RNA level since no gene amplification is observed; conversely, in in vitro models such as the embryonal stem cell line NTERA-2 and the choricarcinoma JEG-3 cell line, VEGF (but not PIGF) mRNA expression is regulated by hypoxic stress.

Base Sequence↗
PubMed1996

Development of thyroid papillary carcinomas secondary to tissue-specific expression of the RET/PTC1 oncogene in transgenic mice.

Gene rearrangements activating the RET proto-oncogene are frequently associated with human thyroid carcinomas belonging to the papillary subtype. These arrangements cause the fusion of the tyrosine-kinase domain of RET to the 5'-terminal region of different genes creating the RET/PTC chimeric oncogenes. Here we report the generation of transgenic mice lines expressing the RET/PTC1 oncogene under the control of the thyroid-specific rat thyroglobulin promoter. RET/PTC1-transgenic mice developed thyroid tumors displaying the histological aspect of papillary carcinomas. These tumors were slowly progressive and did not cause premature death of the animals. Two additional mice developed areas of thyroid hyperplasia. Immunohistochemical and reverse-transcriptase polymerase chain reaction analyses confirmed the thyroid-specific expression of the transgene. Given the frequency of activating rearrangements of RET in human papillary thyroid carcinomas we conclude that this animal system could be a good model for studying the neoplastic progression of thyroid carcinomas.

Animals↗
PubMed1996

[The pharmacological treatment of supraventricular atrioventricular nodal reentry or accessory pathway reentry tachycardias: the usefulness of transesophageal electrophysiological study in the selection of therapy].

Transesophageal atrial pacing is a diagnostic and therapeutic tool in patients with supraventricular reciprocating tachycardia (SVRT). The aim of the present study was to evaluate the effectiveness of transesophageal atrial pacing in the selection of the chronic treatment of SVRT. Between June 1993 and March 1995 we have performed transesophageal atrial pacing in 44 patients affected by atrioventricular nodal reentry tachycardia (AVNRT: n = 28) or atrioventricular reentrant tachycardia (AVRT) using a concealed or manifest bypass tract (n = 16). After a basal (free drug state) transesophageal atrial pacing, we performed serial electropharmacological tests during chronic treatment with sotalol (160 mg/die), flecainide (200 mg/die) and propafenone (450 mg/die). At the end of these tests, the patients were finally discharged with the drug that allowed a more difficult induction or a wider cycle length, and that showed a better clinical tolerance. At the end of the electropharmacological tests 53.6% of the patients affected by AVNRT were discharged with sotalol, 17.8% with propafenone and 28.6% with flecainide. The follow-up of these 28 patients is 11.4 +/- 1.7 months. In the 79.2% of the patients the drug is still effective (absence of whatever episode of SVRT in the follow-up period). In the AVRT group, at the end of the electropharmacological tests, 25% of the patients were discharged with sotalol, 6.25% with propafenone, and 68.75% with flecainide. The follow-up of these 16 patients is 11.7 +/- 1.8 months. In the 78.6% of the patients the drug is still effective (absence of episode of SVRT in the follow-up period).

Adolescent↗
PubMed1996

[An unusual case of ectopic atrial tachycardia: triggered activity as an arrhythmogenic mechanism].

We report a rare case of ectopic atrial tachycardia induced by ergometric stress test whose arrhythmogenic mechanism, after transesophageal electrophysiological study, seemed to be triggered activity. The patient was successfully treated with a beta-blocker (metoprolol), confirming the importance of autonomic modulation in the genesis of arrhythmias caused by afterdepolarizations.

Adrenergic beta-Antagonists↗
PubMed1995

Dbl expression driven by the neuron specific enolase promoter induces tumor formation in transgenic mice with a p53(+/-) genetic background.

The dbl oncogene, generated by the truncation of the amino-terminal portion of the proto-oncogene sequence, encodes a guanine-nucleotide-releasing factor. The transforming activity of this oncogene has never been demonstrated in vivo or in vitro except in the NIH 3T3 mouse fibroblast cell line. The expression of the proto-dbl transcript is confined to tissues and tumors of neuroectodermal derivation. Therefore, to study the transforming activity of the dbl oncogene in vivo, we have generated transgenic mice that express this oncogene in neuroepithelial tissues. Mice carrying the dbl oncogene did not develop a tumor. Successively, to establish whether dbl interacts with the tumor suppressor gene p53 in tumorigenesis, we have used a p53 deficient mouse strain. The results reported here indicate that dbl is capable of causing tumor formation in vivo when its expression is driven in an appropriate cellular and genetic environment.

Animals↗
PubMed1995

Cancer: a biological problem without any natural immunological solution? A unified theory, with implications for grafts, pregnancy and tumour immunoprophylaxis.

Stem tumour cells would be paraembryonal cells, major histocompatibility complex lacking and able of inducing adjoining cells to become tumour differentiated cells with major histocompatibility complex; thus, they would generate a histological tumour organization into paraembryonal cell clusters surrounded by tumour-differentiated cells. Such an organization, actually found in recent studies, might be one factor responsible for the limits of the immunotherapies carried out so far. But, there might be another, perhaps more important, factor. Analysis of ontogenetic aspects of MHC-nonrestricted immunity would lead, indeed, to the prediction that natural killer clones reactive for stem tumour cells (paraembryonal cells) would be missing in the adult organism, since they would be deleted in particular ontogenetic phases. This might explain why natural killer cells locate only in certain organs and nearly not at all in tumour sites. By such an analysis, possible evolutive and functional correlations between natural killer cells and heat shock proteins, hemopoietic histocompatibility, major histocompatibility complex molecules are suggested. From here, explanations and implications for grafts, pregnancy and tumour immunoprophylaxis arise.

Adult↗
PubMed1993

Production of transgenic mice expressing the Ki-ras oncogene under the control of a thyroglobulin promoter.

Transgenic mice have been generated bearing three fusion genes consisting of: (a) a 900-base pair rat thyroglobulin promoter followed by a gene coding for a chloramphenicol acetyl transferase activity; (b) the same promoter followed by the complementary DNA of the human activated Ki-ras oncogene; (c) a 2000-base pair rat thyroglobulin promoter followed by the complementary DNA of the human activated Ki-ras. We have shown that the 900-base pair rat thyroglobulin promoter is able to direct the expression of the reporter gene specifically in the thyroid gland of transgenic mice. The mice bearing the two Ki-ras constructs, which express the transgene in thyroid glands, show thyroid abnormalities, although at very low incidence. These lesions appear after a long latency and with a benign aspect, thus suggest that, in agreement with literature data on naturally occurring human thyroid tumors, the action of an activated ras gene is not sufficient to attain a complete malignant conversion of thyroid glands in vivo. However, ras expression in thyroid follicular cells represents a favorable ground for tumor development, as shown by the fact that goitrogen stimulation experiments increase the occurrence of tumors.

Adenoma↗
PubMed1992

IL-1, IL-6, and PDGF mRNA expression in alveolar cells following stimulation with a tobacco-derived antigen.

To test the hypothesis that inflammatory cytokine production might be an early event in the development of the disease associated with smoking, we used alveolar cells from healthy nonsmokers stimulated with TGP as a model system. TGP, a phenol-rich glycoprotein which is present in tobacco leaves and cigarette smoke condensate, activates the immune system. It stimulates polyclonal B cell differentiation, induces primarily an IgE response, and activates human leukocytes to produce IL-1. Using in situ nucleic acid hybridization we show that the steady-state levels of IL-1 alpha, IL-1 beta, IL-6, platelet-derived growth factor (PDGF)-A, and PDGF-B mRNAs are consistently elevated in the alveolar cells of all donors following TGP stimulation. The kinetics of mRNA expression suggest that IL-1 alpha and IL-1 beta mRNAs are independently regulated in alveolar cells, while the regulation of PDGF-A and PDGF-B mRNA seems to be similar. The activated cells also synthesize elevated levels of IL-1 and IL-6. These findings lend support to the suggestion that some clinical consequences of smoking might be initiated and enhanced by the production of inflammatory cytokines. Moreover, IL-6 could also activate a polyclonal B cell response, which could lead to the synthesis of autoantibodies and thus cause immune-mediated tissue injury.

Antigens↗
PubMed1992

Immunological correlations between ontogenesis and oncogenesis: theoretical implications and suggestions for tumor immunotherapy.

The previously hypothesized paraembryonal nature of tumor cells (1) leads one to suggest, immunologically, the presence in a tumor of two main cell populations: one consisting of either genotypically or phenotypically paraembryonal cells (PECs), with no differentiation MHC (major histocompatibility complex) antigens, and representing the stem tumor cells; the other consisting of phenotypically differentiated-paraembryonal cells (DPECs), with either embryonal or differentiated antigens, rising from neighbour genotypically normal cells induced by PECs. PECs, without MHC antigens, might escape alpha beta TCR (T-cell alpha beta receptor) lymphocyte immunosurveillance, since alpha beta TCR T-cells recognize only MHC-restricted antigens, such as DPEC antigens. On the other hand, PECs might be recognized by gamma delta TCR lymphocytes, known to constitute a more primitive immunosurveillance system, able to recognize non-MHC-restricted antigens. On this ground, several immunological aspects of the tumors are analysed and suggestions for a more effective tumor immunotherapy are given.

Animals↗
PubMed1989

Two peaks of interleukin 1 expression in human leukocytes cultured with tobacco glycoprotein.

We have previously shown that tobacco glycoprotein (TGP), a polyphenol-rich glycoprotein isolated from tobacco or from cigarette smoke, affects the immune system. In this study we show that TGP induces human PBL and adherent cells to produce IL-1 alpha and IL-1 beta. Two peaks of IL-1 activity were observed; one at 18-24 h, the second at 4-6 d after initiation of culture. A similar pattern was observed for the steady state level of IL-1 mRNA. These data suggest that the production of IL-1 by cells stimulated with TGP might be a factor in cardiovascular disease associated with cigarette smoking.

Antigens↗
PubMed1989

Phylogenesis--ontogenesis--oncogenesis.

Ontogenesis might be considered as the development of phylogenetically consequent genic systems that mainly imply: homoeotic genes and ras protooncogene in segmentation; ras and myc protooncogenes in gastrulation; ras, myc and other nuclear protooncogenes in organogenesis; ras myc, other nuclear and cytomembrane protooncogenes in growth-differentiation. Oncogenesis is considered as the stable regression of a transformed cell into a "para-embryonal" gene-phenotypical condition, and it is usually presented as a three-phased process: mutational events on nuclear protooncogenes-myc in particular-would determine "initiation"; other mutations on cytomembrane protooncogenes-ras, especially-would determine "promotion"; other events would finally prevent the cell from carrying out its genic programme completely, thus maintaining the reiterated expression of primitive genic systems (gastrulation and organogenesis), the embryonal products of which-malignant in an adult organism-would determine tumoral "progression".

Animals↗