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Biomedical subjects

L Marchetti

Publications and source records attributed to L Marchetti.

At least 19 recordsLinked to original sources
PubMed2007

Phthalate esters immunolocalized in the gastrointestinal tract of shi drum Umbrina cirrosa (L.) and rainbow trout, Oncorhynchus mykiss (W.).

The occurrence of phthalate esters in freshwater and marine aquacultural species like rainbow trout Oncorhynchus mykiss and shi drum Umbrina cirrosa, respectively, were determined by immunohistochemical approach. The results showed a similar distribution in the gastrointestinal tract of both species. In particular, intense immunoreactivity was found at gastric gland level. In the intestinal tract, goblet cells failed to stain, whereas enterocytes showed the highest binding of phthalates restricted to the apical cytoplasm. This distribution of phthalate esters at gastric gland and enterocyte level may have implications for the physiology of the digestive process and intestinal biotransformation. Phthalates are confirmed to be widely diffused contaminants, absorbed via the alimentary canal; thus a multidisciplinary approach could be useful to examine sea and freshwater environments.

Animals↗
PubMed2006

NR2C by NR2B subunit exchange in juvenile mice affects emotionality and 5-HT in the frontal cortex.

The N-methyl-D-aspartate receptor (NMDA-R) has been inter alia implicated in synaptic plasticity, brain development and emotional processes. The NMDA-R is a multiprotein complex composed of NR1, NR2 and/or NR3 subunits. We generated NR2C-2B mutant mice in which an insertion of NR2B cDNA into the gene locus of the NR2C gene replaced NR2C by NR2B expression throughout the brain. This NR2C-2B mutant was used to examine whether an NMDA-R subunit exchange in juvenile mice would affect emotional behaviors and acetylcholine (ACh), dopamine (DA) and serotonin (5-HT) content in the frontal cortex (FC) and brain structures, which are part of the brain defense system, such as the periaqueductal grey matter (PAG). Juvenile, 1-month-old NR2C-2B mice showed increased open arm avoidance in the elevated plus-maze and increased fear-induced immobility. In terms of brain neurochemistry, NR2C-2B mice showed an increase in 5-HT levels in the FC at the age of 2 months. A correlational analysis revealed that mice with low open arms avoidance had high levels of ACh in the PAG but reduced 5-HT levels in the FC. Animals which showed high levels of fear-induced immobility also had high levels of 5-HT in the FC. These results suggest that the replacement of subunit NR2C by NR2B in juvenile mice increases anxiety- and fear-related behaviors possibly due to changes in FC-5-HT and PAG-ACh levels.

Acetylcholine↗
PubMed2006

Microbial reductive dechlorination of weathered and exogenous co-planar polychlorinated biphenyls (PCBs) in an anaerobic sediment of Venice Lagoon.

The occurrence of reductive dechlorination processes towards pre-existing PCBs and five exogenous coplanar PCBs were investigated in a contaminated sediment of Porto Marghera (Venice Lagoon, Italy) suspended, under strictly anaerobic conditions, in water collected from the same site. PCB dechlorination started after five months of incubation, when sulfate initially occurring in the microcosms was completely depleted and methanogenesis was in progress. It was ascribed to sulfate-reducing bacteria. Several pre-existing hexa-, penta- and tetra-chlorinated biphenyls were slowly bioconverted into tri- and di-, ortho-substituted PCBs from the 5th to the 16th month of experiment. Spiked coplanar PCBs, i.e., 3,3',4,4'-tetrachlorobiphenyl, 3,3',4,4',5- and 2,3',4,4',5-pentachlorobiphenyls, 3,3',4,4',5,5'- and 2,3,3',4,4',5-hexachlorobiphenyls, were extensively transformed (by about 90%) into lower chlorinated congeners, such as 3,3',5,5'-/2,3',4,4'-tetrachlorobiphenyl, 3,3',5-, 2,4,4'-, 2,3',4- and 2,3',5-trichlorobiphenyl, 3,4-/3,4'- and 3,3'-dichlorobiphenyl and 2-chlorobiphenyl. The reductive dechlorination of spiked PCBs did not influence significantly the biotransformation rate and extent of pre-existing PCBs.

Anaerobiosis↗
PubMed2006

Cholinergic cells in the nucleus basalis of mice express the N-methyl-D-aspartate-receptor subunit NR2C and its replacement by the NR2B subunit enhances frontal and amygdaloid acetylcholine levels.

It is known that glutamatergic and cholinergic systems interact functionally at the level of the cholinergic basal forebrain. The N-methyl-d-aspartate receptor (NMDA-R) is a multiprotein complex composed of NR1, NR2 and/or NR3 subunits. The subunit composition of NMDA-R of cholinergic cells in the nucleus basalis has not yet been investigated. Here, by means of choline acetyl transferase and NR2B or NR2C double staining, we demonstrate that mice express both the NR2C and NR2B subunits in nucleus basalis cholinergic cells. We generated NR2C-2B mutant mice in which an insertion of NR2B cDNA into the gene locus of the NR2C gene replaced NR2C by NR2B expression throughout the brain. This NR2C-2B mutant was used to examine whether a subunit exchange in cholinergic neurons would affect acetylcholine (ACh) content in several brain structures. We found increased ACh levels in the frontal cortex and amygdala in the brains of NR2C-2B mutant mice. Brain ACh has been implicated in neuroplasticity, novelty-induced arousal and encoding of novel stimuli. We therefore assessed behavioral habituation to novel environments and objects as well as object recognition in NR2C-2B subunit exchange mice. The behavioral analysis did not indicate any gross behavioral alteration in the mutant mice compared with the wildtype mice. Our results show that the NR2C by NR2B subunit exchange in mice affects ACh content in two target areas of the nucleus basalis.

Acetylcholine↗
PubMed2004

Lectin cytochemistry on developing rat submandibular gland primary cultures.

Lectin cytochemistry was performed in vitro on primary cultures from the rat submandibular gland. For this purpose, prepubertal rats (17, 27, 33 days old) of both sexes were used. Several types of medium supplements were tested and it was found that cells survived until 15 days in presence of all medium supplements and extracellular matrix gel. The binding patterns of all FITC/TRITC-labeled lectins, with and without prior sialidase digestion and deacetylation, were analyzed in a confocal laser scanning microscope. In particular, the occurrence of C4 acetylated sialic acid linked to beta-galactose at day 27 and the presence of fucose residues at day 33 indicated that lectin probes applied to cultured cells give results similar to those obtained in intact tissues and can be used as markers of growth and differentiation.

Acetylglucosamine↗
PubMed2003

Occurrence of beta-endorphin binding sites in the pituitary of the frog Rana esculenta: effect of beta-endorphin on luteinizing hormone secretion.

The possible effect of proopiomelanocortin-derived peptide, beta-endorphin on frog gonadotrope cells was investigated. Binding and internalization of beta-endorphin to pituitary pars distalis cultured cells were visualized by immunofluorescence and analyzed by means of confocal laser scanning microscopy. Using biotinylated endorphin, the time-course of beta-binding showed that this opioid was internalized through receptor-mediated endocytosis, the mechanism in which actin and clathrin were involved; then, the lysosomal degradation program occurred at later stages. The beta-endorphin binding was well antagonized by Naloxone, the opiate receptor antagonist, and up-regulated since more rapid response was obtained in the previously primed cells. The double immunostaining reaction for beta-endorphin and LH beta-subunit revealed that half the beta-endorphin labeled cell population was positively immunostained for LH beta-subunit, and beta-endorphin was able to induce an increasing trend of LH secretion in cultured pars distalis cells. Therefore, it seems that beta-endorphin acts directly on pituitary pars distalis and influences gonadotropin secretion through the interaction with its own receptor.

Actins↗
PubMed2003

In situ visualization of o-phthalate esters in gastrointestinal tract of the frog Rana esculenta.

The regional distribution and relative occurrence of phthalates were studied immunohistochemically by confocal laser scanning microscopy in the alimentary tract of the green frog, Rana esculenta, using an antibody against o-phthalate esters. Many positive sites indicating the basal presence of phthalate esters were identified. The immunoreactive cells were located in the gastric glands of the stomach and in the intestinal epithelium regions with variable frequencies. The regional distribution of phathalate-accumulating cells resembled that of fish and demonstrated that these endocrine disruptors not only enter via the alimentary canal, but also bioaccumulate inside cells specialized in secretion as well as absorption functions.

Animals↗
PubMed2003

Infective endocarditis due to Staphylococcus aureus involving three cardiac valves. A case study.

A 20-year-old woman, diagnosed with coarctation of the aorta, situs viscerum inversus, and bicuspid aortic valve, underwent corrective surgery for the coarctation. After a postoperative neurological state that suggested a spinal lesion, corticosteroid therapy was initiated and the patient was discharged early from the unit to begin a motor rehabilitation program. Following the dehiscence of the thoracotomy surgical wound, a severe infective clinical picture, sustained by methicillin-resistant S. Aureus (MRSA), became evident with a diagnosis of bacterial endocarditis involving the aortic, mitral and tricuspid valves and caused the patient's death due to septic shock complicated by ARDS. According to the authors, the early discharge of the patients after such a complex operation, the eccessive lengthening of the steroid therapy that would have contribuited to delay the diagnosis, causing the lack of preventing identification of the first signs of infection and the impossibility for the patient to have another operation (involving 3 valves) are conclusive elements that led to the above mentioned complications.

Abnormalities, Multiple↗
PubMed2002

Effects of phthalate esters on actin cytoskeleton of Py1a rat osteoblasts.

We evaluated, by confocal laser scanning microscopy, the actin cytoskeleton of immortalized rat Py1a osteoblasts treated with phthalate esters (butyl benzyl phthalate, BBP and dibutyl phthalate, DBP), endocrine disruptors with estrogenic activity. We observed some peculiar modifications of actin cytoskeleton and cells changing from a spindle shape to a rounded form. In particular, F-actin formed thick bundles around the cell membrane but only a weak labeling was observed in rounded cells. Also influence on apoptosis and short-term effects on FGF-2 were studied. It was found that BBP and DBP exert their action in a similar way, act in a transient manner and do not induce apoptosis.

Actins↗
PubMed2001

Mechanism of protonation of [Pt(3)(mu-PBu(t)(2))3(H)(CO)2], yielding the hydride-bridged [Pt(3)(mu-PBu(t)(2))2(mu-H)(PBu(t)(2)H)(CO)2]OTf (Tf=CF(3)SO(2)), and the spectroscopic and theoretical characterization of a kinetic intermediate.

The reaction of the Pt(I)Pt(I)Pt(II) triangulo cluster Pt(3)(micro-PBu(t)()(2))(3)(H)(CO)(2) (1) with TfOH (Tf = CF(3)SO(2)) affords the hydride-bridged cationic derivative [Pt(3)(mu-PBu(t)()(2))(2)(mu-H)(PBu(t)()(2)H)(CO)(2)]OTf (2). With TfOD the reaction gives selectively [Pt(3)(mu-PBu(t)(2))(2)(mu-D)(PBu(t)(2)H)(CO)(2)]OTf (2-D(1)), implying that the proton is transferred to a metal center while a P-H bond is formed by the reductive coupling of one of the bridging phosphides and the terminal hydride ligand of the reagent. The reaction proceeds through the formation of a thermally unstable kinetic intermediate which was characterized at low temperatures, and was suggested to be the CO-hydrogen-bonded (or protonated) [Pt(3)(mu-PBu(t)(2))(3)(H)(CO)(2)].HOTf (3). An ab initio theoretical study predicts a hydrogen-bonded complex or a proton-transfer tight ion pair as a possible candidate for the structure of the kinetic intermediate.

Journal Article↗
PubMed2001

Contributions of intercalated duct cells to the normal parenchyma of submandibular glands of adult rats.

The parenchyma of the submandibular gland in the adult male rat is self-renewing, with most newly formed acinar and granular duct cells believed to differentiate from the rapidly proliferating intercalated duct (ID) compartment. Since the ID cells are phenotypically diverse, based on their different expression of perinatal secretory proteins, we systemically injected tritiated thymidine for 24 hours, and followed the pattern of thymidine distribution in cells by autoradiography and immunocytochemistry of defined cellular phenotypes over a 1-month chase period. Proliferating cells were found within all parenchymal cell compartments; they were most numerous in ID, and primarily in those cells lacking immunoreactivity for the perinatal proteins SMG-B1, -C, and -D. The labeling index (LI) of the ID cells reached a peak at 7 days postinjection, and then decreased over the next 3 weeks. Concurrently, the LI increased significantly in those cells at the junctions of ID with both acini and granular ducts, and also within these larger parenchymal elements. We conclude that the ID cells not reactive for perinatal proteins proliferate to expand the ID compartment, and that ID cells at the ends of the ducts differentiate into both acinar and granular duct cells. Our data provide no evidence for the differentiation of ID cells into cells of striated ducts (SD); however, the small number of excretory duct (ED) profiles seen in our preparations showed extremely high LI (>25%), suggesting that more extensive data might reveal a precursor role for the ED in replacement of SD cells. In addition to the stepwise passage of cells from ID to other parenchymal elements at their junctions, the reported occurrence of occasional clusters of B1-positive acini (BAC) among the typical B1-negative acini had suggested an alternate pathway, in which entire segments of newly expanded ID might develop directly into a recapitulated perinatal stage of B1-reactive cell, pursuant to becoming mature acinar cells. Consistent with this suggestion, the BAC had a fourfold greater LI than typical adult acini; moreover, when analyzed by electron microscopic immunocytochemistry, they appeared similar to the novel perinatal Type III cells both ultrastructurally and in their pattern of B1-immunogold labeling. In contrast, the less common acini showing a sublingual gland phenotype had no significant difference in LI from typical acinar cells. Overall, our results emphasize the importance of the nonimmunoreactive ID cells in normal cellular replacement, and the possibility that ID can undergo en bloc differentiation into replacement acini as well as incremental addition of single cells at the boundaries of ID with acini and with granular ducts.

Animals↗
PubMed2001

Biodegradation of synthetic and naturally occuring mixtures of mono-cyclic aromatic compounds present in olive mill wastewaters by two aerobic bacteria.

Two bacterial strains, Ralstonia sp. LD35 and Pseudomonas putida DSM 1868, were assayed for their ability to degrade the monocyclic aromatic compounds commonly found in olive mill wastewaters (OMWs). The goal was to study the possibility of employing the two strains in the removal of these recalcitrant and toxic compounds from the effluents of anaerobic treatment plants fed with OMWs. At first, the two strains were separately assayed for their ability to degrade a synthetic mixture of nine aromatic acids present in OMWs, both in growing- and resting-cell conditions. Then, due to the complementary activity exhibited by the two strains, a co-culture of the two bacteria was tested under growing-cell conditions for degradation of the same synthetic mixture. Finally, the degradation activity of the co-culture on two fractions was studied. Both fractions one deriving from natural OMWs through reverse osmosis treatment and containing low-molecular weight organic molecules, and the other obtained from an anaerobic lab-scale treatment plant fed with OMWs, were rich in monocyclic aromatic compounds. The co-culture of the two strains was able to biodegrade seven of the nine components of the tested synthetic mix (2, 6-dihydroxybenzoic acid and 3, 4, 5-trimethoxybenzoic acid were the two undegraded compounds). In addition, an efficient biodegrading activity towards several aromatic molecules present in the two natural fractions was demonstrated.

Bacteria, Aerobic↗
PubMed2001

Phthalate esters influence FGF-2 translocation in Py1a rat osteoblasts.

Exposure of the Py1a rat osteoblastic cells to butyl benzyl phthalate (BBP) and dibutyl phthalate (DBP) showed that these endocrine disrupting chemicals (EDC) strongly and reversibly affect the cytoplasmic fibroblast growth factor-2 (FGF-2) translocation into the nucleus in a dose-dependent and time-related manner. Stimulation of cells with high concentrations of BBP or DBP for short timing gave results comparable to those of cells treated with low concentrations for long timing. By confocal laser scanning microscope (CLSM) analysis it was found that the first relevant effect resulted in an accumulation of FGF-2 near the nuclear envelope, sometimes in the shape of clusters; the growth factor was then translocated into the nucleus and, finally, after long periods of exposure, the basal nuclear and cytoplasmic binding, typical of unstimulated cells, was re-established. In addition it was found that phthalate esters did not affect the FGF receptor 2 (FGFR-2) but decreased Con A binding indicating a possible inhibition of collagen fiber assembly. The different concentrations and timing of exposure of BBP and DBP affected the FGF-2 modulation in a similar way. Noticeable cumulative effects of BBP and DBP were not observed.

Animals↗
PubMed2000

Cell death during development of intercalated ducts in the rat submandibular gland.

Programmed cell death, or apoptosis, occurs during the development of many tissues and organs in almost all multicellular organisms. Although apoptosis of salivary gland cells has been demonstrated in several pathological conditions, the role of apoptosis in the postnatal development of the salivary glands is unknown. We have studied the development of the rat submandibular gland (SMG) during its transition from the perinatal stage to the mature adult stage. Terminal tubule or Type I cells, which synthesize the secretory protein SMG-C, are prominent in the perinatal acini and are believed to form the intercalated ducts of the adult gland. Between 25 days and 30 days after birth, the number of Type I cells and their SMG-C immunoreactivity markedly decreased. Apoptotic cells in association with the developing intercalated ducts were labeled with the Terminal Deoxyribonucleotidyl Transferase-Mediated dUTP Nick End Labeling (TUNEL) method. Between 25 and 40 days of age, from 50 to 80% of the apoptotic cells in cryostat sections of the SMG were closely associated with the intercalated ducts. Electron microscopy showed that the Type I cells became vacuolated, their secretory granules were reduced in size and number, and the amount of rough endoplasmic reticulum was decreased. Cellular debris resembling apoptotic bodies was phagocytosed by macrophages and adjacent intercalated duct cells. These observations suggest that the loss of Type I cells and reduction of SMG-C immunoreactivity during development of the intercalated ducts of the adult rat SMG is due, at least in part, to apoptosis.

Animals↗
PubMed2000

Role of the reactor configuration in the biological detoxification of a dump site-polychlorobiphenyl-contaminated soil in lab-scale slurry phase conditions.

The biotreatability of a xenobiotic contaminated soil is frequently determined through a bioslurry treatment usually performed in lab-scale shaken baffled flasks. In this study, a 3-1 unconventional stirred tank reactor was developed and tested in the slurry-phase treatment of a soil heavily contaminated by polychlorobiphenyls (PCBs) derived from an Italian dump site, in the absence and in the presence of biphenyl and of the exogenous PCB aerobically dechlorinating co-culture ECO3. The data obtained were compared with those obtained on the same soil in experiments performed in parallel in 3-1 baffled shaken flask reactors. Considerably higher PCB removal and soil detoxification yields (determined through the Lepidium sativum germination test and the Collembola mortality test) were attained in the stirred tank reactors, which generally displayed a higher slurry-phase homogeneity and a higher availability of biphenyl- and chlorobenzoic acid-degrading bacteria compared to the corresponding shaken flask reactors. Moreover, enhanced soil PCB biodegradation and detoxification yields were observed when the developed reactor was supplemented with biphenyl and the exogenous ECO3 bacteria. In conclusion, the results of the soil biotreatability experiments commonly performed in bioslurry lab-scale reactors are significantly influenced by the reactor configuration; the use of the unconventional stirred tank reactor system developed in this work is recommended.

Bacteria↗
PubMed2000

Nuclear and cytoplasmic lectin receptor sites in rat Py1a osteoblasts.

The intracellular distribution of lectin receptor sites was studied in the rat Pyla osteoblasts using immunofluorescence at the confocal microscopy level. This immortalized cell line was found to represent a satisfactory model to study the occurrence and distribution of sugar moieties. Our data showed distinct affinity patterns of lectins recognizing different terminal or internal sugar residues. For some lectins, the binding patterns appeared to be cell cycle-independent, whereas for PNA the cell cycle greatly influenced the nuclear binding. By combining lectin affinity with sialidase degradation and alcoholic saponification the sialic acid acceptor sugars and derivatives were also visualized. In particular, glycoconjugates with sialic acids linked to beta-galactose, and mainly C4 acetylated, were located in the cytoplasm, while glycoconjugates characterized by sialic acids linked to alpha-N-acetylgalactosamine, and devoid of acetyl groups at C4, were almost exclusively found in the nucleus. The comparison of lectin affinities, with and without prior glycosidase digestions, allowed us to gain further insight into the chemical composition of glycoconjugates that act as the lectin receptor sites that appeared to belong to O- and N-linked glycoconjugates. The use of additional enzymatic treatments were useful to better establish the localization of nuclear receptor sites and results were compared with previous studies about endogenous and exogenous lectins in an attempt to reconcile the association of lectins and sugars within the nucleus and their possible involvement in modulation of cell proliferation and/or response to chemical signals. The above digestions also provided information about the cytoplasmic binding patterns.

Ammonium Sulfate↗
PubMed2000

Cellular compartmentation of lysozyme and alpha-amylase in the mouse salivary glands. Immunogold approaches at light and electron microscopy level.

The research was planned to study the subcellular distribution of enzymatic secretory products within the secretory structures of the mouse major salivary glands at light and electron microscopy level by immunogold silver stain (IGSS) technique and double-sided post-embedding immunogold binding and silver amplification in order to speculate about their compartmentation. In particular, we experimented the above immunogold labeling approaches to localize the lysozyme and to verify its distribution patterns in relation to another secretion enzyme, alpha-amylase. Co-presence of lysozyme and alpha-amylase was observed in the convoluted granular tubule cells of the submandibular gland and in the demilunar cells of the sublingual gland as well as in the electron-dense regions of the mottled secretory granules in the parotid gland. Exclusive binding patterns of lysozyme were observed in the acinar cells of the submandibular and sublingual glands where alpha-amylase did not occur.

Animals↗