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Biomedical subjects

E Simoni

Publications and source records attributed to E Simoni.

At least 19 recordsLinked to original sources
PubMed2006

Uranyl complexation by chloride ions. Formation of a tetrachlorouranium(VI) complex in room temperature ionic liquids [Bmim][Tf2N] and [MeBu3N][Tf2N].

The tetrachlorouranium(VI) complex is formed in [Bmim][Tf2N] and [MeBu3N][Tf2N] from a uranium(VI) solution in the presence of a stoichiometric quantity of chloride ions. The [UVIO2Cl4]2- absorption and emission spectra show bands splitting in comparison with the [UVIO2]2+ spectra, as observed in the solid state, organic solvents, and chloroaluminate-based ionic liquids. The fluorescence lifetime of [UO2Cl4]2- in [MeBu3N][Tf2N] is 0.7 +/- 0.1 mus. The reduction potential of this complex is -1.44 and -1.8 V vs Ag/Ag+ respectively in [Bmim][Tf2N] and [MeBu3N][Tf2N] and does not depend on the chloride concentration. The mechanism proposed for the redox process is a monoelectronic reduction to form [UVO2Cl4]3-, followed by a chemical reaction. The tetrachlorouranium(V) complex seems more stable in [Bmim][Tf2N] than in [MeBu3N][Tf2N]. The electrochemical analysis put in evidence specific interactions of the ionic liquid cation with the uranium anionic species.

Journal Article↗
PubMed2006

Cellular alterations in different organs of European sea bass Dicentrarchus labrax (L.) exposed to cadmium.

Specimens of farmed European sea bass (Dicentrarchus labrax L., 1758) were exposed to different cadmium (Cd) concentrations (4.47, 5.63, 7.08 and 8.91 mg l(-1)) for 24 and 48 h. The effects of Cd on numbers of some cell types and structures (i.e., chloride cells, CCs; macrophage aggregates, MAs; rodlet cells, RCs) and on structure and ultrastructure of the main organs (gill, liver, intestine, kidney) were studied with routine process for light and transmission electron microscopy. Following cadmium exposure, the numbers of branchial CCs as well as intestinal and renal RCs increased significantly within 24h. Increase in metal concentration did not affect the magnitude of the numerical increment of the aforementioned cells. Moreover, in treated fish (24 and 48 h) the numbers of MAs in both head kidney and spleen were significantly higher than in control conspecifics, whilst the global area of MAs was less influenced by the acute treatment. In exposed sea bass, all the examined organs exhibited cellular modifications which appeared time- and dose-dependent. The gills showed telangectasia, lamellar fusion, oedema, epithelial lifting and leukocyte infiltration. In the liver, kidney and intestine acute cell swelling and vacuolization were common. Ultrastructurally the alterations observed frequently in hepatocytes, tubular epithelial cells and enterocytes included presence of numerous myelinoid bodies, damaged mitochondria, dilatation of endoplasmic reticulum, high number of lysosomes and autophagolysosomes. In intestinal and kidney tubular epithelia of treated fish, rodlet cells displayed some anomalies like dilatation of nuclear envelope, cytoplasmic vacuolization, presence of myelinoid bodies, rodlets degeneration and extensive discharge activity.

Animals↗
PubMed2006

Effects of experimental terbuthylazine exposure on the cells of Dicentrarchus labrax (L.).

The effects of acute exposure to the herbicide terbuthylazine (3.55, 5.01 and 7.08 mg l(-1)) on the cells of farmed European sea bass, Dicentrarchus labrax L., were investigated by means of light and electron microscopy. In gills of treated fish, the number of chloride cells (CCs) and rodlet cells (RCs) increased significantly within 24 h and 48 h, respectively; the intestine showed the largest increase in RCs linked to treatment and exposure time. In kidney, 24 h exposure induced a significant increase in RCs and the number and global area of macrophage aggregates (MAs). Treated fish displayed cellular and/or ultrastructural alterations in all the organs examined. In the gills necrosis, lamellar and cellular oedema, epithelial lifting, telangectasia, and fusion of secondary lamellae were encountered. The liver presented myelin-like figures, cytoplasmic rarefaction and acute cell swelling of hepatocytes. In both organs, the severity of damage was dose-dependent. In RCs of gills, the intestine and kidney of exposed sea bass, high cytoplasmic vacuolization, myelin-like figures, cristolysis and varying degrees of rodlet degeneration were observed. Extensive rodlet expulsion occurred in the gut lumen. Exposure to terbuthylazine also affected the renal tubular epithelial cells, which exhibited 'blebs'. Damage to the intestinal epithelial cells was also observed.

Analysis of Variance↗
PubMed2005

Changes in the neuromodulators of the diffuse endocrine system of the alimentary canal of farmed rainbow trout, Oncorhynchus mykiss (Walbaum), naturally infected with Eubothrium crassum (Cestoda).

A histopathological and immunohistochemical study on the intestines of 45 specimens of farmed rainbow trout, Oncorhynchus mykiss (Walbaum), from Loch Awe, Scotland, revealed a number of cellular deviations in individuals naturally infected with the pseudophyllidean cestode Eubothrium crassum (Bloch, 1779). Twenty-five individuals (55.5%) were infected with an average worm burden of 18.84 +/- 4.06 (mean +/- SE) cestodes per host (range, 2-80 worms; total 471 worms). The cestodes, measuring an average 8.23 +/- 1.10 cm (mean +/- SE; range, 5.3-13.0 cm) in length, were found attached by their scolices to the mucosal lining of the distal portion of the pyloric caeca. Within the caeca, the strobila evoked a mild catarrhal enteritis, namely an enhanced mucus production with epithelial cellular desquamation, a leucocytic infiltration of the lamina propria-submucosa and vacuolization of the intestinal epithelial cells. Eosinophilic granular cells of the stratum granulosum exhibited granular depletion, while within the catarrh, the presence of a high number of rodlet cells was noticed. Immunohistochemically, the occurrence of E. crassum caused a significant reduction in the number of bombesin-, gastrin-releasing peptide and glucagon-like immunoreactive endocrine cells, but an increase in the relative densities of endocrine cells containing cholecystokinin-8- and gastrin-like substances. There were, however, no significant differences in the number of endocrine cells that were immunoreactive to secretin, neuropeptide Y and peptide histidine-isoleucine antisera in the digestive tracts of either the infected or non-infected O. mykiss.

Animals↗
PubMed2005

Response of the gut neuroendocrine system of Leuciscus cephalus (L.) to the presence of Pomphorhynchus laevis Müller, 1776 (Acanthocephala).

Immunohistochemical tests were applied to sections of intestine of uninfected and Pomphorhynchus laevis Muller-infected chub, Leuciscus cephalus (L.) using 15 different antisera. Nerve cell bodies and fibres immunoreactive (IR) to the anti-bombesin, -Cholecystokinin-8 (CCK-8), -galanin, -Gastrin-Releasing Peptide (-GRP), -Nitric Oxide Synthase (-NOS), -Substance P (-SP), and -Vasoactive Intestinal Peptide (-VIP) sera were observed in the myenteric plexus of uninfected chub. The density of nerve components immunoreactive to these antisera was high in the intestine of the infected fish, especially near the site of attachment. Moreover, numerous nerve fibres, immunoreactive to anti-bombesin, -GRP, -galanin, -SP, and -VIP sera, were encountered in the connective tissue capsule surrounding the bulb and proboscis of P. laevis. The occurrence of P. laevis in the chub gut significantly increased the number of endocrine cells per intestinal fold immunoreactive to galanin, met-enkephalin and leu-enkephalin antisera. CCK-8, Neuropeptide Y and glucagon-like immunoreactive cells were less numerous in the intestine of infected chub. A large number of cells in the tunica propria-submucosa of L. cephalus infected with P. laevis were immunoreactive to anti-serotonin and -leu-enkephalin sera.

Acanthocephala↗
PubMed2004

Immunohistochemistry, histopathology and ultrastructure of Gasterosteus aculeatus tissues infected with Glugea anomala.

Immunohistochemical and histopathological studies were conducted on a population of 3-spined sticklebacks Gasterosteus aculeatus (L.) from Loch Airthrey (Stirling, Scotland) naturally infected with the microsporean Glugea anomala (Moniez 1887). Of the 55 host specimens that were examined, 16 (29.09%) were infected, the intensity of infection ranging from 1 to 4 xenomas per fish, which were principally located within the central portion of the body lateral flank musculature. All 32 G. anomala xenomas examined were mature, their diameter ranging from 936 to 2232 Pum, and their walls of presented a laminar structure. Subcutaneously situated xenomas protruded from the fish body surface, whilst xenomas encountered within the intestine were seen to cause distortion. Light and electron microscopical observations confirmed a host cellular reaction around the xenoma, seen by the presence of eosinophile granule cells (EGCs), and some neutrophils. The occurrences of rodlet cells among the intestinal epithelial cells, and in close proximity to the xenoma wall, were observed in certain specimens. Outside the xenoma wall, macrophage aggregates (MAs) were commonly encountered. Within the xenoma wall, the presence of eosinophile granular cells immunoreactive to the anti-serotonin serum was also recorded. Further immunohistochemical tests revealed that a high number of nerve fibres running along the white lateral muscle fibres were immunoreactive to bombesin-, galanin-, and leu-enkephalin-antisera. Nerve fibres containing bombesin- and leu-enkephalin-like substances were also observed in the connective inflammatory tissue around the protozoan cyst, while neurons in the spinal ganglia were immunoreactive to met-enkephalin, and serotonin antisera. The control for the specificity of immunohistochemical reactions was performed using preabsorption tests of each antiserum with the corresponding antigen, and no immunoreactivity was noticed. The data presented are discussed in relation to the occurrence of G. anomala, which alters the pattern of nerve fibres present in the host. Specifically, the protozoan induces a response in the stickleback nervous system, the reaction of which is revealed through the application of immunohistochemical techniques.

Animals↗
PubMed2004

Use of spectroscopic techniques for uranium(VI)/montmorillonite interaction modeling.

To experimentally identify both clay sorption sites and sorption equilibria and to understand the retention mechanisms at a molecular level, we have characterized the structure of hexavalent uranium surface complexes resulting from the interaction between the uranyl ions and the surface retention groups of a montmorillonite clay. We have performed laser-induced fluorescence spectroscopy (LIFS) and X-ray photoelectron spectroscopy (XPS) on uranyl ion loaded montmorillonite. These structural results were then compared to those obtained from the study of uranyl ions sorbed onto an alumina and also from U(VI) sorbed on an amorphous silica. This experimental approach allowed for a clear determination of the reactive surface sites of montmorillonite for U(VI) sorption. The lifetime values and the U4f XPS spectra of uranium(VI) sorbed on montmorillonite have shown that this ion is sorbed on both exchange and edge sites. The comparison of U(VI)/clay and U(VI)/oxide systems has determined that the interaction between uranyl ions and montmorillonite edge sites occurs via both [triple bond]AlOH and [triple bond]SiOH surface groups and involves three distinct surface complexes. The surface complexation modeling of the U(VI)/montmorillonite sorption edges was determined using the constant capacitance model and the above experimental constraints. The following equilibria were found to account for the uranyl sorption mechanisms onto montmorillonite for metal concentrations ranged from 10(-6) to 10(-3) M and two ionic strengths (0.1 and 0.5 M): 2[triple bond]XNa + UO2(2+) <==> ([triple bond]X)2UO2 + 2Na+, log K0(exch) = 3.0; [triple bond]Al(OH)2 + UO2(2+) <==> [triple bond]Al(OH)2UO2(2+), log K0(Al) = 14.9; [triple bond]Si(OH)2 + UO2(2+) <==> [triple bond]SiO2UO2 + 2H+, log K0(Si1) = -3.8; and [triple bond]Si(OH)2 + 3UO2(2+) + 5H2O <==> [triple bond]SiO2(UO2)3(OH)5- + 7H+, log K0(Si2) = -20.0.

Bentonite↗
PubMed2003

Surface complexation modeling of uranium(VI) sorbed onto lanthanum monophosphate.

Sorption/desorption are basic processes in the field of contaminant transport. In order to develop mechanistically accurate thermodynamic sorption models, the simulation of retention data has to take into account molecular scale informations provided by structural investigations. In this way, the uranyl sorption constants onto lanthanum monophosphate (LaPO(4)) were determined on the basis of a previously published structural investigation. The surface complexation modeling of U(VI) retention onto LaPO(4) has been performed using the constant capacitance model included in the FITEQLv3.2 program. The electrical behavior of the solid surface was investigated using electrophoretic measurements and potentiometric titration experiments. The point of zero charge was found to be 3.5 and surface complexation modeling has made it possible to calculate the surface acidity constants. The fitting procedure was done with respect to the spectroscopic results, which have shown that LaPO(4) presents two kinds of reactive surface sites (lanthanum atoms and phosphate groups). The uranyl sorption edges were determined for two surface coverages: 40 and 20% of the surface sites that are occupied, assuming complete sorption. The modeling of these experimental data was realized by considering two uranyl species ("free" uranyl and uranyl nitrate complex) sorbed only onto phosphate surface groups according to the previously published structural investigation. The obtained sorption constants present similar values for both surface complexes and make it possible to fit both sorption edges: logK(U)=9.4 for z.tbnd;P(OH)(2)+UO(2)(2+)<-->z.tbnd;P(OH)(2)UO(2)(2+) and logK(UN)=9.7 for z.tbnd;P(OH)(2)+UO(2)NO(3)(+)<-->z.tbnd;P(OH)(2)UO(2)NO(3)(+).

Journal Article↗
PubMed2003

Sorption of uranium (VI) species on zircon: structural investigation of the solid/solution interface.

This work is an investigation of the mechanisms of interaction between uranium (VI) ions and zirconium silicate. The speciation of uranium (VI) sorbed on zircon was studied using four complementary techniques as probes of the local structure around the uranium atom: laser spectrofluorimetry, X-ray photoelectron spectroscopy (XPS), diffuse reflectance infrared Fourier-transformed (DRIFT) spectroscopy, and EXAFS spectroscopy. The sorption of uranyl on zirconium oxide was also studied to allow structural comparisons. Spectrofluorimetry and XPS results allowed an identification of the silicate sorption sites on the solid. These methods associated with spectrofluorimetry and DRIFT led to a characterization of the sorbed surface complexes, taking into account the influence of the nature of the background salt and of the pH on the structure of the U(VI) surface species. EXAFS measurements, either on air-dried samples or in situ, were then carried out on well-characterized samples and allowed identification of the sorption mechanism on zircon as the formation of an inner-sphere polydentate surface complex.

Journal Article↗
PubMed2003

Effects of conspecifics and heterospecifics on individual worm mass in four helminth species parasitic in fish.

Intraspecific and interspecific effects on the growth and body size of helminths are rarely studied in natural situations, yet knowing what determines helminth sizes and thus fecundity is crucial to our understanding of helminth ecology and epidemiology. The determinants of average individual worm mass were investigated in four common species of helminths parasitic in trout, Salmo trutta. In the acanthocephalan Echinorhynchus truttae, there was a negative relationship between the intensity of infection by conspecifics and average individual worm size. However, in the acanthocephalans Pomphorhynchus laevis and Acanthocephalus anguillae and in the cestode Cyathocephalus truncatus, the relationship was positive: individual worms were larger on average when co-occurring with many conspecifics than when co-occurring with very few. In addition, the average mass of individual C. truncatus in a host decreased as the total mass of other helminth species in the same host increased. This interspecific effect involves the whole helminth community, as the combined effect of all other helminth species is a better predictor of reduced mass in C. truncatus than the mass of any other species taken on its own. These results illustrate the importance of considering helminth interactions and helminth growth in a natural setting.

Acanthocephala↗
PubMed2001

The cement apparatus of larval and adult Acanthocephalus anguillae (Acanthocephala), with notes on the copulatory cap and origin of gland secretion.

Light and electron microscopy were used to investigate the ultrastructure of the cement apparatus, namely cement glands and cement ducts, of mature specimens of the parasite Acanthocephalus anguillae (Muller, 1780) Luhe, 1911 recovered from the alimentary canal of fish Leuciscus cephalus (Risso, 1826). In addition, the cement apparatus of immature A. anguillae found within the body cavity of the crustacean Asellus aquaticus (L.) was examined. In immature and mature males of Acanthocephalus anguillae, there are six round cement glands and each of them has an outer cytoplasmic layer containing nuclei and surrounds a space for storage of the cement. The cytoplasmic layer produces round, membrane-bound secretory granules approximately 1 microm in diameter. Nuclei and other cellular organelles surrounded by secretory granules were noticed inside the luminal part of the gland of adult males. In some female Acanthocephalus anguillae, within the attached copulatory cap, eggs and spermatozoa were observed. A protein of about 23 kDa appeared to be the major component of proteins of isolated cement glands, as well as in detached copulatory caps.

Acanthocephala↗
PubMed2000

Rodlet cells and other inflammatory cells of Phoxinus phoxinus infected with Raphidascaris acus (Nematoda).

Rodlet cells (RCs), and other inflammatory cells, namely eosinophile granule cells (EGCs), eosinophilic granulocytes and epithelioid cells in the liver, pancreas and peritoneal serosa of uninfected and naturally parasitized minnow Phoxinus phoxinus (Linnaeus, 1758), were studied by light and electron microscopy. Forty-eight minnows were examined and in 18 fishes encysted larvae of the nematode Raphidascaris acus (Bloch, 1779) were encountered, mainly in the pancreas. The number of larvae in the latter organ ranged from 2 to 46. Nematode larvae were encapsulated by epithelioid granulomata, and these cells displayed typical epithelial characteristics such as desmosomes and tonofilaments. EGCs and RCs characteristically surrounded the reactive foci and were suggestive of an integrated inflammatory network involving both cell types. In many instances RCs were noticed at the periphery of the pancreas, beneath the peritoneal serosa, partially or entirely surrounded by mesothelial cells. In the latter situation partially damaged RCs were present in the splancnic cavity entirely surrounded but not truly phagocytized (no phagolysosome occurred) by mesothelial cells, which shared the same ultrastructural features of epithelioid cells. This phenomenon has never been described and may represent a peculiar turnover of RCs in the pancreas likely related to the high sensitivity to damage. A significant difference (p < 0.01) in the number of RCs between uninfected and parasitized fish was noticed in the liver and pancreas. The data suggest that RCs represent an inflammatory cell type closely linked to other piscine inflammatory cells, such as EGCs, epithelioid cells and mesothelial cells.

Animals↗
PubMed1998

Structural Environment of Uranium (VI) and Europium (III) Species Sorbed onto Phosphate Surfaces: XPS and Optical Spectroscopy Studies.

In order to characterize the structure of the surface complexes formed by interaction between uranyl and europium (III) ions and the surface of solid matrices, optical and X-ray photoelectron spectroscopies experiments on uranyl/europium loaded phosphate solids (Th4P2O7(PO4)4, ZrP2O7, and Zr2O(PO4)2) have been performed. The use of complimentary spectroscopic techniques allows an identification of the sorption mechanism and a structural characterization of the sorption sites and the sorbed species on phosphate surfaces. The samples were prepared from aqueous uranyl or europium solutions in the pH range from 1.5 to 6.0. The surface coverage was varied from 1 to 40 % of a monolayer. The differences between the emission spectra of europium ions either sorbed on the surface of phosphate samples or doped inside the solid unambiguously indicates that these sorbed ions are exclusively located on the surface and that they do not migrate inside the matrix, which shows clearly that surface complexation is involved during the sorption process. The U4f XPS spectrum of uranyl ions sorbed on zirconium diphosphate exhibits only one component, while the spectrum corresponding to uranium on thorium matrix shows two different unresolved peaks attributed to two different chemical environments. These results, corroborated by the uranyl emission spectra and the associated decay times and those obtained by optical spectroscopy of europium sorbed on the same solids, have been interpreted in terms of two sorption sites probably formed by the oxygens of the PO4 and P2O7 surface groups. Copyright 1998 Academic Press.

Journal Article↗
PubMed1995

Transient hyperphosphatasemia of infancy and childhood. A study of serum alkaline phosphatase by electrofocusing techniques.

OBJECTIVE: To evaluate serum alkaline phosphatase (ALP) isoenzymes, using a sensitive electrofocusing technique, in transient hyperphosphatasemia of infancy and childhood. DESIGN: Randomized study of infants and children who provided serum samples when an unusual magnitude of total ALP activity was noted. SETTING: Reference enzyme laboratories in Gorizia and Bergamo (Italy) and in Charleston, SC (USA). PATIENTS: A total of 135 infants and children noted to have markedly increased total ALP activity. MAIN OUTCOME MEASURES: Recognition of the disease pathogenesis with appropriate treatment instituted. RESULTS: Three groups of patients were identified: (1) previously healthy patients who showed additional laboratory evidence of viral and protozoal infection, in whom the ALP isoenzyme pattern reflected the primary target organ(s) of the infection; (2) patients with clinical evidence of failure to thrive due to preexisting disease, along with a superimposed infection (the ALP isoenzyme pattern reflected the specific infection and fractions associated with the primary disease); and (3) patients exhibiting failure to thrive (nonorganic or caloric deficit) who did not show evidence of infection. The total ALP in the third group was lower than in the other groups, was of hepatic and bone origin, and decreased when a positive caloric balance was established. CONCLUSION: We examined several mechanisms to explain the hyperphosphatasemia. A perplexing question remains: Will a small group of infants and children respond to infection with this magnitude of ALP activity? Conversely, do all children respond, but a small number fortuitously undergo laboratory measurements that include ALP levels?

Alkaline Phosphatase↗
PubMed1989

[The surgical cure of the sequelae of noma (cancrum oris). A report of 2 cases].

The surgical treatment of the sequelae in the patients affected by noma is possible even in emerging countries if the surgeon carefully evaluates each patient individually choosing simple, safe, sound and satisfactory techniques which are conditioned by sex and age of the patients. Two cases of sequelae treated with different techniques are described.

Adolescent↗
PubMed1983

Resuscitative thoracotomy for patients with traumatic injury.

The clinical course and final outcome were determined for 63 trauma victims who underwent resuscitative thoracotomy (RT) for hypovolemic cardiac arrest in the Department of Emergency Medicine during a 24-month period. The objectives of the study were to determine the efficacy of and indications for RT and to define the prognostic signs for survival. Of 63 patients, six were successfully resuscitated (9.5%), and five of these were discharged from the hospital (7.9%). The presence of pupillary reactions was an extremely reliable indicator of successful outcome (P = 0.0009), as was the presence of some respiratory effort (P = 0.025). None of the victims of blunt trauma (n = 6) or severe head injury (n = 13) survived. Three of 17 patients (17.6%) with stab wounds and two of 36 (5.6%) with gunshot wounds survived the procedure. RT was beneficial in 13.6% of patients who had isolated organ system injuries, but no patient with injuries to more than two organ systems survived. Victims of isolated penetrating thoracic trauma had an 11.8% survival rate, as opposed to a 0% survival rate for those with abdominal trauma. The best prognosis was in victims with penetrating cardiac injuries, who had a 22.7% survival rate. The cost of RT averaged $1660 per patient, exclusive of physician charges. In our experience, RT is most beneficial for victims of penetrating thoracic trauma, especially those with cardiac injuries. However, routine use of this high cost/low benefit procedure cannot be recommended for patients who have cardiac arrest secondary to blunt trauma or severe head injuries. Also, it is not recommended for patients whose pupillary reflexes and respiratory movements are absent.

Adolescent↗
PubMed1976

[Bleeding fibroma of the small intestine].

A case of serious, recurrent enterorrhagia is reported. The cause could not be identified with normal diagnostic tools and was discovered only after explorative laparotomy. The finding was benign ulcerated tumour of the small intestine, histologically defined as fibroma with fluorishing cellularity.

Female↗