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Biomedical subjects

M Camatini

Publications and source records attributed to M Camatini.

At least 19 recordsLinked to original sources
PubMed2006

Histopathological effects induced by paraquat during Xenopus laevis primary myogenesis.

The oxidative agent paraquat induced tail abnormalities during Xenopus laevis development. Specimens exposed from blastula to the tadpole stage revealed pear-shaped myocytes and irregular intersomitic boundaries. The histological feature of the axial musculature was evaluated in embryos sampled at significant stages of the primary myogenesis. During the somitogenesis PQ-treated embryos showed normal appearing myotomes, but reduced PAS activity in the post-rotating myotomal cells, and myoblasts with slight vacuolations. Once etched from the vitelline envelope, embryos showed severely altered myoblasts with irregular cellular apexes, heavy sarcoplasmic vacuolations, pyknotic nuclei and disorganizing intersomitic boundaries. Myotomes with many necrotic myocytes containing disorganized contractile material and heavily malformed intersomitic boundaries characterized the late myogenic stages. Our results evidence the heaviest PQ histopathological effects to affect myogenesis of post-etched embryos, suggesting a possible linkage between the swimming activity and the oxidative damage to muscle tissue.

Animals↗
PubMed2002

Comet assay evaluation of DNA single- and double-strand breaks induction and repair in C3H10T1/2 cells.

Ionizing radiation is a potent inducer of DNA damage because it causes single- and double-strand breaks, alkali-labile sites, base damage, and crosslinks. The interest in ionizing radiation is due to its environmental and clinical implications. Single-strand breaks, which are the initial damage induced by a genotoxic agent, can be used as a biomarker of exposure, whereas the more biologically relevant double-strand breaks can be analyzed to quantify the extent of damage. In the present study the effects of 137CS gamma-radiation at doses of 1, 5, and 10 Gray on DNA and subsequent repair by C3H10T1/2 cells (mouse embryo fibroblasts) were investigated. Two versions of the comet assay, a sensitive method for evaluating DNA damage, were implemented: the alkaline one to detect single-strand breaks, and the neutral one to identify double-strand breaks. The results show a good linear relation between DNA damage and radiation dose, for both single-strand and double-strand breaks. A statistically significant difference with respect to controls was found at the lowest dose of 1 Gy. Heterogeneity in DNA damage within the cell population was observed as a function of radiation dose. Repair kinetics showed that most of the damage was repaired within 2 h after irradiation, and that the highest rejoining rate occurred with the highest dose (10 Gy). Single-strand breaks were completely repaired 24 h after irradiation, whereas residual double-strand breaks were still present. This finding needs further investigation.

Animals↗
PubMed1998

Molecular approaches to evaluate pollutants.

Many organisms are in use to test pollutants and their extensive variability clearly emerges from reviews since researchers in the world are involved in continuous effort to set up new assays and to improve those already in use. In the present paper we focus the attention on the mixed function oxidase system and the DNA adduct formation which are two biomarkers widely used and extensively studied in mammals and fish by different Authors. We compare their results with the ones we obtained in amphibians, which result to be a good model. Moreover we present some significative results obtained by the use of cultured cell lines to test the herbicide MCPA. The results obtained demonstrate that the amphibian Xenopus is a suitable indicator for induction of cytochrome P-450 by B[a]P as well as for production of DNA adducts. Cultured cells evidenced that cytoskeletal array and thiol proteins are molecular targets of the herbicide used, demonstrating that risk assessment can be properly analysed in in vitro systems.

2-Methyl-4-chlorophenoxyacetic Acid↗
PubMed1998

Identification of a multixenobiotic resistance mechanism in Xenopus laevis embryos.

In the '90's a membrane-associated transport protein, discovered in aquatic organisms, was considered to be expressed in response to environmental xenobiotics. Like the multidrug resistance protein found in mammalian tumor cell lines, this protein confers resistance in organisms in polluted areas by binding xenobiotics and transporting them out of the cells in an energy-dependent manner. This study investigates the expression and the activity of a P-glycoprotein (Pgp) involved in a multixenobiotic resistance mechanism (MXRM) during the early developmental stages and in tissues of adult Xenopus laevis.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Human-derived cell lines to study xenobiotic metabolism.

In vitro systems make for rapid identification of xenobiotic effects and can be used to study cellular and subcellular toxicity mechanisms. In this report the metabolic competence of two human-derived cell lines, a hepatic (Hep G2) and a pulmonary one (A549) was tested. In the two cell systems the capability to activate Benzo[a]Pyrene through the cytochrome P450 enzyme system and to form reactive metabolites was analysed. 3H-BaP and the scintillation counting analysis were used to show the differences of the metabolic activity in Hep G2 and A549. A similar time course of 3H-BaP uptake was observed in the cell systems. Nevertheless, in the two cell lines the distribution of radioactive metabolites seemed to reflect a specific tissue response to toxicity.

Benzo(a)pyrene↗
PubMed1998

Physical-chemical and ecotoxicological evaluation of water based drilling fluids used in Italian off-shore.

In order to evaluate the effects on the marine ecosystem caused by an eventual discharge into sea of water based drilling fluids, as current legislation allows, chemical and ecotoxicological analyses were performed on the most common drilling muds and products used in Italian off-shore activities. The chemical analysis on drilling fluids involved the leaching test and the measurement of total content of heavy metals, whereas biodegradation tests were performed on the products used in mud's formulations. As for ecotoxicological evaluation, two marine organisms, the crustacean Artemia salina and the diatom Phaeodactylum tricornutum, were selected to determine the LC50 and the EC50 respectively.

Animals↗
PubMed1995

Benomyl affects the microtubule cytoskeleton and the glutathione level of mammalian primary cultured hepatocytes.

Rat primary hepatocyte cultures have been used to study the effect of Benomyl alone or in combination with Pirimiphos-methyl. The results presented demonstrate that Benomyl alone is responsible for the microtubular disorganization in both a time- and dose-dependent manner, that the effect is reversible after the agent is removed, and that Benomyl is a potent glutathione-depleting agent. Pirimiphos-methyl, alone or combined with Benomyl had no effect on microtubule organization, but reinforced the decrease in glutathione.

Animals↗
PubMed1994

Lethality, teratogenicity and growth inhibition of heptanol in Xenopus assayed by a modified frog embryo teratogenesis assay-Xenopus (FETAX) procedure.

The frog embryo teratogenesis assay-Xenopus (FETAX), a powerful test for the presence of developmental toxicants, has been modified mainly by performing an in vitro fertilization and increasing the exposure time to 112 h. The modified assay (modFETAX) that presents several advantages over the original FETAX methodology has been validated by the use of ZnSO4, a standard teratogen for FETAX. The modFETAX has been applied to evaluate the 1-heptanol effects on mortality, malformation and growth inhibition. The results indicate that heptanol causes a significant growth inhibition of Xenopus tadpoles and that LC50 and TC50 at 120 h are, respectively, 1.49 and 0.37 mM; the resulting teratogenic index (TI50) of 4.03 suggests that heptanol is a strong teratogen.

Alcohols↗
PubMed1994

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) affects the actin cytoskeleton and calcium level of Swiss 3T3 mouse fibroblasts.

Organization of the actin cytoskeleton, the cytosolic free-calcium concentrations and ATP levels were analyzed in 3T3 mouse fibroblasts treated with 0.75 or 1.5 mM MPTP. In the presence of the drug actin filaments were time- and dose-dependently disorganized, ATP level was unaffected and intracellular calcium increased within 5 s. The correlation between MPTP cytotoxicity and [Ca2+]i level emerging from these results, suggests that the primary effect of the molecule itself is on the plasma membrane's integrity for calcium ion regulation.

Actins↗
PubMed1993

Actin, alpha-actinin, and vinculin are associated with septate junctions in Insecta.

Cytoskeletal elements associated with the smooth septate junctions linking the midgut columnar cells of Manduca sexta larvae (Insecta, Lepidoptera) were characterized. Myosin subfragment 1 decoration and immunostaining for actin demonstrated that the filaments associated with the septate junctions were constituted of actin. Moreover, using a combination of immunochemical and immunolocalization techniques, evidence is presented that alpha-actinin, myosin II, and vinculin are localized close to the specialized plasma membranes. The insertion of microfilament bundles into submembranous F-actin/alpha-actinin/vinculin complexes, previously described in vertebrate junctions of adherens type, appears to be a more general organization, including the insect septate junction here examined.

Actin Cytoskeleton↗
PubMed1992

Cytoskeletal elements in mammalian spermiogenesis and spermatozoa.

Identification of the cytoskeletal elements and their role in the formation as well as the maintenance of head membrane compartmentalization is a much debated issue in mammalian spermatozoa. Data which have emerged during the last ten years are summarized. Those which have converged in a common opinion, such as the distribution of actin in mammalian spermiogenesis, are distinguished from those which have to be confirmed, such as the role of actin related proteins and actin in mature spermatozoa.

Actins↗
PubMed1992

The molecular architecture of an insect midgut brush border cytoskeleton.

The cytoskeletal apparatus of the vertebrate intestinal brush border (BB) has served as a model system for the actin-based cytoskeleton of nonmuscle cells. In this study, we examine the structural organization and molecular architecture of the BB cytoskeleton expressed in the midgut of lepidopteran larvae, Manduca sexta. Electron microscopy of the midgut of the 5th instar larvae revealed enterocytes with an apical BB surface comparable to that in the vertebrate intestine, with both microvillar (MV) and terminal web (TW) domains, the latter defined by a zone of organelle exclusion directly beneath the MV. As reported previously for the larval dragon fly, the MV contain a bundle of actin filaments, as determined by staining with rhodamine phalloidin (Kukulies, J., et al., Protoplasma 121, 157-162 (1984)) and heavy meromyosin decoration (Komnick, H., J. Kukulies, Zoomorphology 107, 241-253 (1987)). Two-dimensional gel analysis revealed the presence of multiple isoelectric variants of actin with the major isoform corresponding to the non-muscle actin isoform II, expressed in Drosophila. Like the vertebrate BB, the Manduca BB can be isolated intact from enterocytes by mechanical shear. Immunochemical analysis of isolated BB fractions or whole homogenates of midgut revealed proteins of appropriate molecular weight immunoreactive with antibodies to the MV core proteins: BB myosin I, villin and fimbrin, and the TW components: spectrin, myosin II and tropomyosin. Immunocytochemical localization of a subset of these proteins at the light microscopic (spectrin) and electron microscopic (actin, villin, spectrin, myosin II, and tropomyosin) level reveals that the molecular architecture of the Manduca BB cytoskeleton is homologous to that found in vertebrates.

Animals↗
PubMed1991

N-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induces cytoskeletal alterations on 'Swiss 3T3' mouse fibroblasts.

The effect of the neurotoxin MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) on Swiss 3T3 cells was investigated. Cell morphology alterations were observed when 3T3 cell cultures were exposed for 6 h to 1.5 mM MPTP. Using indirect immunofluorescence technique, cytoskeletal elements' organization of microfilaments and microtubules, has been analysed. MPTP modified both actin and tubulin networks, stress fibers appeared less sharp and microtubules were disorganized. The effect of MPTP was completely reversible and cell viability was unaffected. These results suggest that changes in cytoskeletal organization may be the first visible effect related to biochemical alterations induced by MPTP.

Actins↗
PubMed1991

Identification of spectrin and calmodulin in rabbit spermiogenesis and spermatozoa.

Actin was localized in the four subacrosomal bulges (Camatini et al., Eur. J. Cell Biol. 45:276-281, 1987), which characterize the sperm head of rabbit spermatozoa (Phillips, J. Ultrastruct. Res. 38:591-604, 1972), and in the postacrosomal region (Welch and O'Rand, Dev. Biol. 109:411-417, 1985; Camatini et al., Eur. J. Cell Biol. 45:276-281, 1987). Specific antibodies and indirect immunogold labelling on testis Lowicryl K4M sections and spermatozoa cryosections were used to study the distribution of calmodulin and a spectrin-like protein. This protein was also present close to the shaping membranes of the head. The results presented suggest a membrane-cytoskeletal role of actin, spectrin, and calmodulin.

Animals↗
PubMed1990

Spermiogenesis in Xenopus laevis: from late spermatids to spermatozoa.

Spermatogenesis is a complex morphogenetic process in which microfilaments and microtubules have been shown to play an important role. The last steps of Xenopus spermatogenesis, i.e., the corkscrew shaping of the sperm head, have been followed to study actin and microtubule distribution by conventional and immunoelectron microscopy. During sperm head morphogenesis, actin is absent in the elongating spermatids, but it is present in the Sertoli cells where results localized at the periphery of their cytoplasm that surrounds the developing germ cells. Sertoli cell actin and microtubules may assist the elongation and the shaping of the spermatids and function in maintaining the Sertoli-spermatid association.

Actins↗
PubMed1988

Characterization of actin isoforms in ejaculated boar spermatozoa.

Actin was localized in boar ejaculated spermatozoa by using specific antisera against cytoplasmic isoforms of actin [Otey et al., J Cell Biol, 102:1726-1737, 1986; Skalli et al., J Cell Biol, 103:2787-2796, 1986; Miller et al., Biochemistry, 26:6064-6070, 1987]. Indirect immunofluorescence and immunoelectron microscopy showed that gamma and beta actins were codistributed in the acrosomal and postacrosomal regions. Sperm actin was also identified on two-dimensional gel as two spots in the isoelectric point and molecular weight corresponding to beta and gamma actins. Coelectrophoresis of sperm actin and chicken gizzard actin and immunoblots stained with the specific antibodies confirmed the presence of these two isoforms of actin.

Actins↗