1,354,493 research outputs found
Parte speciale
No full textL’evoluzione scientifica, culturale ed economica del genere umano, ha portato alla definizione di modelli alimentari basati sull’utilizzo di poche specie, vegetali ed animali, dalle quali si ottengono le materie prime necessarie alla preparazione di alimenti. Lo sfruttamento, sempre più spinto e razionale, di un ben definito gruppo di specie vegetali, non include, oggi, le piante officinali, ovvero quelle piante utilizzate, in passato, nelle officine farmaceutiche per la preparazione di medicinali. Le piante officinali, nell’accezione più ampia, includono anche quelle per uso aromatico e cosmetico, alle quali potrebbero essere aggiunte, oggi, anche quelle coloranti, ad attività biocida e funzionale. Le specie officinali hanno avuto, in passato, grande diffusione ed interesse per l’uomo poiché, mancando i prodotti di sintesi, erano le uniche fonti dalle quali trarre medicamenti, aromi, cosmetici, e molte altre sostanze di uso comune. Il progresso della chimica ha permesso di produrre, per via sintetica, gran parte delle sostanze ottenute dalle piante officinali; l’interesse per questa categoria di piante, di conseguenza, si è molto ridotto, fino a scomparire, in alcuni casi. Nonostante l'attuale disponibilità di un gran numero di prodotti artificiali, idonei a sostituire efficacemente i medicamenti, gli aromi, i cosmetici e molte altre sostanze ottenibili dal mondo vegetale, si assiste, oggi, ad un rinnovato interesse per le piante officinali. Tale fenomeno è dettato, in parte, da mode che sono destinate a mutare, ma anche dalla crescente richiesta di disporre di prodotti naturali, in grado di produrre effetti complessi che le molecole di sintesi non sempre assicurano. Per il momento, non è dato sapere se l'attuale maggiore richiesta di produzioni per impiego officinale possa raggiungere dimensioni tali da interessare, significativamente, l'agricoltura moderna. Riteniamo, tuttavia, che tale settore possa meritare, anche in Italia, un interesse maggiore rispetto al passato, da parte di ricercatori ed operatori. Questa convinzione è l’elemento fondamentale che ha stimolato la preparazione del presente volume: Produzione ed impiego delle piante officinali. Esso vuole sostituire il volume: Coltivazione delle piante medicinali e aromatiche preparato, nel 1986, da Catizone, Marotti, Toderi, Tétény e stampato da Pàtron. Il testo di Produzione ed impiego delle piante officinali è organizzato in una parte generale nella quale vengono, inizialmente, trattati gli elementi di base dell’agronomia al fine di fornire, soprattutto ai non agronomi, conoscenze utili al governo delle colture. Successivamente, sono approfonditi gli aspetti relativi al mercato, all’economia e alla normativa delle piante officinali. Si è ritenuto che tale parte della trattazione potesse incontrare l’interesse di coloro che, per la prima volta, si avvicinano a tale comparto produttivo ma anche di coloro che già vi operano, oltre che degli studenti dei numerosi corsi di tecniche erboristiche, di nutrizione e fitoterapia, presenti, oggi, in molti atenei. Considerevole attenzione è stata dedicata alla trattazione dei principi attivi di maggiore interesse contenuti nelle piante officinali ed al ruolo che i fattori agro-ambientali svolgono su di essi. Lo studio di questi aspetti è di grande importanza tecnologica ed economica dato che essi, in definitiva, influenzano la qualità oltre la quantità delle produzioni. Ai processi post-raccolta è stata dedicata una trattazione alquanto ampia poiché si è ritenuto che questa fase della filiera produttiva, spesso poco nota, dovesse avere una adeguata considerazione, dato che essa può influenzare il risultato finale della produzione sia dal punto di vista qualitativo che quantitativo. L’ultimo capitolo della parte generale è stato dedicato all’utilizzazione, nella cura della salute umana, dei prodotti ottenuti dalle piante officinali. In particolare, i vari principi attivi sono messi in relazione con la pianta che li contiene e l’azione che essi svolgono su un determinato organo o funzione, tenendo, tuttavia, sempre presente che per ogni utilizzo terapeutico la competenza rimane di stretta competenza medica. Si è così ottenuto una sorta di manuale di facile consultazione in grado di fornire precise informazioni, ma anche di soddisfare gli interessi e le curiosità del lettore. La parte speciale include la trattazione di 73 specie che interessano diversi settori d’impiego
Hepatocyte growth factor modulates Sertoli-Sertoli tight junction dynamics.
No full textIn mammalian testes Sertoli cells form tight junctions whose function is fundamental for the maintenance of a normal spermatogenesis. Hepatocyte growth factor (HGF) is a cytokine influencing the cellular tight junctions either in normal or in tumor cells. We have previously demonstrated that HGF is expressed in the rat testis and influences many functional activities of somatic and germ cells. We now report that HGF decreases the levels of testicular occludin and influences the position of the molecule in the tight junctions as demonstrated by confocal microscopy analysis. In fact in the presence of the factor occludin was mainly localized in the suprabasal region of the tubules whereas in its absence occludin was prevalently localized in the basal region. Occludin production is known to be regulated by different cytokines including TGFbeta. We have investigated the role of HGF in the regulation of the levels of TGFbeta and we report that HGF significantly increases the amount of the active fraction of the factor without affecting the amount of the total TGFbeta. Urokinase type plasminogen activator (uPA) is closely related with the tight junctions and is one of the molecules able to activate the inactive TGF-beta. We found that HGF significantly increases the amount of uPA present in the testis suggesting that HGF regulates the amount of active TGFbeta via uPA levels. In conclusion we report that in the testis HGF regulates Sertoli-Sertoli tight junctions inducing a reduction and redistribution of occludin possibly modulating the levels of uPA and active TGFbeta
Pleiotropic activityof hepathocyte growth factor (HGF) during embryonic mouse testis development .
No full textThe hepatocyte growth factor (HGF) is a pleiotropic cytokine whose action is mediated by c-met, a glycoproteic receptor with tyrosine kinase activity which transduces its multiple biological activities including cell proliferation, motility and differentiation. During embryonic development HGF acts as a morphogenetic factor as previously demonstrated for metanephric and lung development. Recently, culturing male genital ridges, we demonstrated that HGF is able to support in vitro testicular cord formation. In the present paper we report the expression pattern of the HGF gene during embryonic testis development and the multiple roles exerted by this factor during the morphogenesis of this organ. Northern blot analysis reveals a positive signal in urogenital ridges isolated from 11.5 days post coitum (dpc) embryos and in testes isolated from 13.5 and 15.5 dpc male embryos. On the contrary HGF mRNA is undetectable in ovaries isolated from 13.5 and 15.5 dpc embryos. Moreover, we demonstrate that HGF is synthesized and secreted by the male gonad and is biologically active. These data indicate a male specific biological function of HGF during embryonic gonadal development. This hypothesis is supported by the in vitro demonstration that HGF acts as a migratory factor for male mesonephric cells which is a male specific event. In addition we demonstrate that during testicular development, HGF acts as a morphogenetic factor able to reorganize dissociated testicular cells which, under HGF stimulation, form a tridimensional network of cord-like structures. Finally, we demonstrate that HGF induces testicular cell proliferation in this way being responsible for the size increase of the testis. All together the data presented in this paper demonstrate that HGF is expressed during the embryonic development of the testis and clarify the multiple roles exerted by this factor during the morphogenesis of the male gonad
HEPATOCYTE GROWTH FACTOR RECEPTOR (C-MET) IS INVOLVED IN EMBRYONIC MOUSE TESTIS DEVELOPMENT.
No full textAbstractThe hepatocyte growth factor (HGF) receptor, c-met, transduces the HGF multiple biological activities. During embryonic development the system HGF/c-met regulates the morphogenesis of different organs and tissues. In this study we examined c-met gene expression during mouse testis development and, by means of Northern blot and in situ hybridization, we report the receptor expression pattern. C-met expression is not detectable in male genital ridges isolated from embryos at 11.5 days postcoitum (dpc). In testes isolated from 12.5 and 13.5 dpc, c-met expression is detectable and essentially localized in the developing cords. Male genital ducts do not express c-met at the reported ages, whereas female ducts appear c-met positive. Moreover, we report that HGF is able to induce testicular morphogenesis in vitro. Male genital ridges isolated from embryos at 11.5 dpc are morphologically nonorganized. Culturing 11.5 dpc urogenital ridges in the presence of HGF we obtained testis organization and testicular cord formation. Our data demonstrate that c-met is expressed during the beginning period of testis differentiation and that HGF is able to support testicular differentiation in vitro. All these data indicate that this growth factor, besides its role as mitogenic factor, plays a fundamental role during testicular cord formation probably inducing cell migration and/or cell differentiation
Studi di lungo periodo sull’inquinamento diffuso da diserbanti
No full textIn questo lavoro vengono presentati i risultati di un quindicennio di ricerche condotte in pieno campo a scala parcellare ed a scala di bacino. Oltre a tali indagini, dal 1996 sono svolte prove di lungo termine, presso l’Azienda dell’Università a Cadriano (BO), per quantificare le perdite di diserbanti nelle acque di drenaggio tubolare. L’obiettivo delle prove è quello di studiare, sul lungo termine, i problemi ambientali legati all’impiego dei diserbanti, in particolare per valutare le perdite per ruscellamento (Ozzano) e la eventuale contaminazione delle acque di falda e di drenaggio sottosuperficiale (Cadriano).
Il confronto tra i risultati ottenuti nelle diverse prove a livello di bacino ed in pieno campo ha permesso di raggiungere una più completa e dettagliata comprensione dell’entità dei fenomeni ambientali legati all’inquinamento diffuso da erbicidi, fornendo importanti indicazioni sulle tecniche agronomiche in grado ridurre l’impatto sull’ambiente. Il database, inoltre, è stato utilizzato per la validazione di modelli matematici per la previsione delle perdite di erbicidi nelle acque di ruscellamento e di drenaggio
Functional role of hepatocyte growth factor receptor during sperm maturation
No full textMammalian spermatozoa acquire motility and fertilizing capacity during their transit through the epididymis. Hepatocyte growth factor (HGF) is a pleiotropic cytokine with potent motogenic capacities that has been identified in different organs, including the mammalian male genital tract. In mice, HGF is present in the testis and, in large amounts, in the distal part of the epididymis. In prepuberal rats, we have demonstrated that HGF is synthesized by the peritubular myoid cells and in men, HGF is present in significant quantities in seminal plasma. It has been suggested that in mice, HGF has a role in initiating sperm motility, whereas in men, no significant correlations between HGF concentration and sperm motility have been found. In the present paper we report that in rats, HGF receptor, c-met, is expressed in testicular and epididymal spermatozoa. Through immunocytochemistry, we have found that c-met is exclusively localized on the head in testicular sperm. A different localization of c-met has been found in sperm isolated from caput and cauda epididymidis. Cells isolated from epididymal caput show a c-met localization exclusively restricted to the head in most cells. In a minority of caput epididymis spermatozoa the receptor is localized both in the cell head and along the flagellum. Spermatozoa isolated from the epididymal cauda were quite homogeneous, showing the receptor localized along the entire cell surface. We also report that HGF is synthesized and secreted by the rat epididymis as indicated by the scatter effect of epididymal cell, homogenate and culture medium on MDCK cells. To clarify whether HGF is involved in the acquisition of sperm motility in the epididymis, its maintenance, or both, spermatozoa isolated from caput epididymidis have been cultured in medium alone or supplemented with HGF. The results obtained indicated that HGF has a positive effect on the maintenance of sperm motility which, in the absence of HGF, significantly decreases during the first hour of culture, whereas it is maintained for at least 3 hours when HGF is present in the culture medium. We also report that HGF does not influence spermatozoa viability as indicated by the cytometrical analysis of propidium iodide-labeled sperm; an equal number of dead cells appeared in control and in HGF-treated preparations. In conclusion, our data strongly support the hypothesis that HGF positively influences sperm motility maintenance during sperm transit through the epididymis, indicating that c-met receptor and its ligand, HGF, have a role in male fertility
Expression and functional role of hepatocyte growth factor and its receptor (c-met) during fetal mouse testis development
No full textThe hepatocyte growth factor (HGF) is a pleiotropic cytokine able to regulate different cellular functions. HGF action is mediated by its receptor, c-met, a glycoprotein with tyrosine kinase activity. We previously demonstrated that c-met is expressed in the newly formed seminiferous cords of the mice embryonic testes and that HGF acts as a morphogenetic factor. In this paper, we report that at 15.5 days post-coitum (dpc) c-met is expressed in the testicular cords, whereas at 18-5 dpc c-met expression is almost exclusively localized in the interstitial tissue of the testis in particular in the fetal Leydig cells. In addition, we demonstrate that HGF gene is expressed during the fetal period of testis development, heavily detectable in the interstitial compartment of 18-5 dpc testes. Interestingly, HGF is not expressed in the Leydig cells that, as above reported, express the HGF receptor. Looking for the functional role of HGF on Leydig cells, we evaluated the amount of testosterone secreted by testes isolated from 18.5 dpc embryos and cultured in the presence of HGF. The results of the in vitro organ culture show that, at this age, HGF increases the amount of testosterone secreted in the culture medium. On the contrary, HGF does not modulate the amount of testosterone secreted by testes isolated from 15-5 dpc embryos. In conclusion, we report that HGF is produced in the interstitial compartment of the developing testis but not by the Leydig cells. Conversely, the HGF receptor c-met is expressed in the Leydig cells and HGF modulates Leydig cell function during the late period of prenatal development
HEPATOCYTE GROWTH FACTOR MODULATES RAT LEYDIG CELL FUNCTONS
No full textHepatocyte growth factor (HGF) is a pleiotropic factor that plays multiple roles during mammalian development. We previously demonstrated that in the postnatal testes, the HGF receptor, c-met, is expressed by Leydig cells and HGF increases the steroidogenetic activity of the cells. In the present article, we report that HGF modifies the composition of the extracellular matrix of cultured Leydig cells. We show that HGF increases the metabolic activity of isolated Leydig cells; in particular, the factor increases urokinase plasminogen activator and matrix metalloproteinase 2 secretion. We have also shown that the levels of active transforming growth factor beta are increased by HGF. On the contrary, using the Western blotting technique, a strong reduction in the amount of fibronectin present in the culture medium of cells cultured in the presence of HGF has been detected. The presented data demonstrate that HGF modulates several functional activities of Leydig cells, further supporting the hypothesis that this factor has a relevant role in the regulation of mammalian spermatogenesis
Embryonic mouse testis development: role of platelet derived growth factor (PDGF-BB).
No full textPlatelet-derived growth factors (PDGFs) are paracrine growth factors mediating epithelial-mesenchymal interactions and exerting multiple biological activities which include cell proliferation, motility, and differentiation. As previously demonstrated, PDGFs act during embryonic development and recently, by culturing male genital ridges, we have demonstrated that PDGF-BB is able to support in vitro testicular cord formation. In the present paper, we report that PDGF-BB is present during embryonic testis development and, in organ culture, induces cord formation although with reduced diameters compared with the cords formed in the genital ridges cultured in the presence of HGF. Moreover we have analyzed the roles exerted by this growth factor during the morphogenesis of the testis. We demonstrate by immunohistochemical experiments that PDGF-BB and its receptors are synthesized by the male UGRs isolated from 11.5 and 13.5 dpc embryos and by Western blot that the factor is secreted in a biologically active form by testicular cells isolated from 13.5 dpc embryos. The biological roles of the factor have also been studied and we demonstrate that PDGF-BB acts as a migratory factor for male mesonephric cells whose migration is a male specific event necessary for a normal testicular morphogenesis. In addition we demonstrate that during testicular development, PDGF-BB induces testicular cell proliferation being in this way responsible for the increase in size of the testis. Finally we demonstrate that PDGF-BB is able to reorganize dissociated testicular cells inducing the formation of large cellular aggregates. However the structures formed in vitro under PDGF-BB stimulation never had a cord-like morphology similar to the cord-like structures formed in the presence of HGF (Ricci et al., 2002, Mech Dev 118:19-28), suggesting that this factor does not act as a morphogenetic factor during testicular development. All together the data presented in this paper demonstrate that PDGF-BB and its receptors (alpha- and beta-subunits) are present during the crucial ages of embryonic mouse testis morphogenesis and indicate the multiple roles exerted by this factor during the development of the male gonad
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