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M Parisi

Publications and source records attributed to M Parisi.

At least 37 records · Page 2Linked to original sources
PubMed1998

Prevalence of rheumatoid arthritis in Italy: the Chiavari Study.

OBJECTIVE: To ascertain the prevalence of rheumatoid arthritis (RA) in an Italian general population. METHODS: The study was performed in the years 1991-92 in Chiavari, a small town located on the Ligurian coast, and involved 4456 subjects aged 16 years or more from four general practices. The subjects received a postal questionnaire developed to detect patients with current or past inflammatory joint diseases. The age and sex distribution of the sample were similar to those of the Italian population from the 1992 census. Patients reporting a history of joint swelling in at least a pair of symmetrical joints were reviewed by a rheumatologist. The clinical records of non-responders and responders who failed to attend the clinic were also reviewed. RESULTS: 3294 of 4456 (73.9%) subjects answered to the questionnaire. The mean (SD) age of the 3294 responders was 48.3 (19.3) years; 53.7% of them were female. Swelling in at least two symmetrical joints was reported by 230 subjects (7%). Among them, 11 patients fulfilling the 1987 ARA criteria for RA were identified. The prevalence of RA was 0.33% (95% CI 0.13, 0.53) in the general population, 0.13% (95% CI 0, 0.31) in men, and 0.51% (95% CI 0.18, 0.84) in women. CONCLUSIONS: These data are consistent with the results of three earlier studies published in the fifties in the Italian literature and confirm that the prevalence of RA is low in Italy and has remained unchanged in the last 40 years.

Adult↗
PubMed1997

A new data-acquisition system for the measurement of the net water flux across epithelia.

We describe a computer-based data-acquisition system designed for the measurement of net water flux across epithelia. It is based on the detection of a liquid meniscus position in a capillary tube using an electro-optical device. Then the data are digitized, transferred to the computer main memory and saved in a file. The advantages of the system are: (a) to measure net water transfer with an accuracy of 50 nl; (b) to switch from absorptive to secretory conditions in real time; (c) data are directly digitized to be analytically, graphically and statistically treated; (d) the specially developed software allows change of time intervals for data acquirement and the scale in graphic events; (e) the software also allows recall to the monitor screen of graphics from previous tests or to print them on paper; (f) a simple mechanical structure, saving maintenance and time; and (g) high reliability.

Animals↗
PubMed1997

Biophysical properties of epithelial water channels.

The biophysical models describing the structure of water pores or channels have evolved, during the last forty years, from a pure 'black box' approach to a molecular based proposal. The initial 'sieving pore' in which water and other molecules were moving together was replaced by a more restrictive model, where water is moving alone in a 'single file' mode. Aquaporins discovery and cloning [G.M. Preston, T.P. Carroll, W.B. Guggino, P. Agre, Science 256 (1992) 365] leaded to the 'hour-glass model' and other alternative proposals, combining information coming from molecular biology experiments and two dimensional crystallography. Concerning water transfers in epithelial barriers the problem is quite complex, because there are at least two alternative pathways: paracellular and transcellular and three different driving forces: hydrostatic pressure, osmotic pressure or 'transport coupled' movements. In the case of ADH-sensitive epithelia it is more or less accepted that regulated water channels (AQP2), that can be inserted in the apical membrane, coexist with basolateral resident water channels (AQP3). The mechanism underlying the so-called 'transport associated water transfer' is still controversial. From the classical standing gradient model to the ion-water co-transport, different hypothesis are under consideration. Coming back to hormonal regulations, other than the well-known regulation by neuro-hypophysis peptides, a steroid second messenger, progesterone, has been recently proposed [P. Ford, G. Amodeo, C. Capurro, C. Ibarra, R. Dorr, P. Ripoche, M. Parisi, Am. J. Physiol. 270 (1996) F880].

Journal Article↗
PubMed1996

Erythrocyte glutathione determination in the diagnosis of glucose-6-phosphate dehydrogenase deficiency.

The levels of reduced glutathione in severe glucose-6-phosphate dehydrogenase deficient red blood cells, were found, when assayed immediately after blood withdrawing, almost equal to those of normal human erythrocytes. On the contrary, if the blood samples were stored at 4 degrees C for 4 days (or more) either as whole blood or as washed erythrocytes with or without glucose, the glutathione concentration of the enzyme-deficient cells decreased to half the initial value. After a mild t-butylhydroperoxide (t-BHP) treatment, only glucose-6-phosphate dehydrogenase deficient red cells exhibited a drastic decrease of glutathione, the normal ones being almost unaffected. If t-BHP-treated erythrocytes were incubated in the presence of glucose or of oxidized glutathione, a full recovery of the inital glutathione concentration was detected only in normal samples. Glucose could not be replaced by any other sugar. When the oxidative stress was induced by addition of methylene blue (MB), the behaviour was similar but less marked, it was however impossible, in this case, to restore the normal glutathione levels, through a subsequent incubation of the MB-treated erythrocytes with oxidized glutathione. This discrepancy can be explained by the finding that a marked inhibition of glutathione reductase was observed in MB-treated erythrocytes, while t-BHP exposure had no direct effect on this enzyme.

Erythrocytes↗
PubMed1996

Progesterone inhibition of water permeability in Bufo arenarum oocytes and urinary bladder.

The ovarian oocytes from Bufo arenarum (BAO) but not those from Xenopus laevis (XLO) would have water channels (WC). We now report that the injection of the mRNA from BAO into the oocytes from XLO increased their water osmotic permeability (Pi) (reduced by 0.3 mM HgCl2 and reversed by 5 mM beta-mercaptoethanol). A 30-min challenge with progesterone induced, 18 h later, a reduction of the mercury-sensitive fraction of Pf in the BAO (but not in XLO). The mRNA from BAO pretreated with progesterone lost its capacity to induce WC in the XLO, but the hormone did not affect the expression of the WC in XLO previously injected with the mRNA from BAO. Pf was also measured in urinary bladders of BAO. Eighteen hours after a challenge with progesterone, a reduction in the hydrosmotic response to oxytocin was observed. Finally, the mRNA from the urinary bladder of BAO was injected into XLO. An increase in Pf was observed. This was not the case if, before the mRNA extraction, the bladders were treated with progesterone. We conclude that the BAO WC share progesterone sensitivity with the oxytocin-regulated water channel present in the toad urinary bladder.

Animals↗
PubMed1996

Prevalence of vision and ocular disease conditions in a clinical pediatric population.

BACKGROUND: The purpose of this study was to fill a significant void in the ophthalmic literature by performing a large scale, comprehensive, prospective study of the prevalence of vision disorders and ocular pathology in a clinical pediatric population using well-defined diagnostic criteria. METHODS: A prospective study was performed on 2,023 consecutive patients between the ages of 6 months and 18 years presenting for an initial comprehensive examination at the Eye Institute of The Pennsylvania College of Optometry. There were 373 subjects between 6 months and 5 years, 11 months of age, and 1,650 subjects between 6 years and 18 years of age. RESULTS: The most important finding from this study is that other than refractive anomalies, the most common conditions optometrists are likely to encounter in a pediatric population are binocular vision and accommodative disorders. The prevalence of accommodative and binocular (strabismic and non-strabismic) vision disorders is 9.7 times greater than the prevalence of ocular disease in children 6 months to 5 years of age, and 8.5 times greater than the prevalence of ocular disease in children 6 to 18 years of age. CONCLUSIONS: The data from this study has great significance for clinicians, optometric educational institutions, health care planners, and administrators. This data suggests that other than refractive anomalies, the most prevalent conditions in the clinical pediatric population are binocular and accommodative disorders. Clinicians should use a minimum data base that includes assessments of accommodation and binocular vision that will allow them to detect conditions with the highest prevalence.

Adolescent↗
PubMed1996

Aquaporins and water transfer across epithelial barriers.

The cloning and molecular characterization of water channels, generically called aquaporins, have marked a pivotal point in our understanding of water movements across epithelial barriers. Nevertheless, the mechanisms underlying water transfer across these barriers at the molecular and cellular level are not yet clarified. We analyze here the role of the different driving forces moving water across epithelia and the biophysical properties of the water channels. We will also review the recently cloned epithelial members of the aquaporin family, including their expression and distribution in different tissues.

Cell Membrane↗
PubMed1996

Water permeability properties of the human small intestine in vitro: effects of Escherichia coli heat-stable enterotoxin.

The net absorptive water flux (Jw), the transepithelial potential difference (PD) and the short-circuit current (Isc) were simultaneously measured in the human small intestine in vitro with the following results: 1) An absorptive Jw was observed when the jejunum or the ileum were mounted between two identical standard solutions in the presence of an hydrostatic pressure gradient (delta P) of 13 cm of water (mucosal side positive). 2) The absorptive Jw was a linear function of the applied delta P or the imposed osmotic transepithelial gradient (delta Osm) in both intestinal segments. The hydrostatic (Phydr) and osmotic (Posm) permeabilities to water for jejunum and ileum were: 0.349 +/- 0.049 cm/s vs. 0.156 +/- 0.022 cm/s and 0.0012 +/- 0.0001 cm/s vs. 0.0019 +/- 0.0003, respectively. 3) A fraction of this absorptive Jw was independent of the presence of any hydrostatic, osmotic or chemical gradient and represented the transport associated to movement of water (Jwt). 4) PD and Isc values were similar in the jejunum and in the ileum but the transepithelial resistance (Rt) was significantly greater in ileum than in jejunum. 5) 2 micrograms/ml of E. coli heat-stable enterotoxin (STa) caused a significant inhibition of the absorptive Jw without modification of Phydr, Posm or Isc. 6) After STa treatment, the absorptive Jwt reverted to a secretory one in the jejunum. In the ileum, STa action caused a 48% decrease in the absorptive Jwt values.

Animals↗
PubMed1995

Pattern of ecological shifts in the diversification of Hawaiian Drosophila inferred from a molecular phylogeny.

BACKGROUND: The endemic Hawaiian drosophilids, a unique group that are remarkable for their diversity and rapid proliferation, provide a model for analysis of the process of insular speciation. Founder events and accompanying random drift, together with shifts in sexual selection, appear to explain the dramatic divergence in male morphology and mating behaviour among these flies, but these forces do not account for their spectacular ecological diversification into a wide array of breeding niches. Although recognized as contributing to the success of this group, the precise role of adaptive shifts has not been well defined. RESULTS: To delineate the pattern of ecological diversification in the evolution of Hawaiian Drosophila, we generated a molecular phylogeny, using nucleotide sequences from the yolk protein gene Yp1, of 42 endemic Hawaiian and 5 continental species. By mapping ecological characters onto this phylogeny, we demonstrate that monophagy is the primitive condition, and that decaying leaves were the initial substrate for oviposition and larval development. Shifts to decaying stems, bark and tree fluxes followed in more derived species. By plotting female reproductive strategies, as reflected in ovarian developmental type, on the molecular tree, we also demonstrate a phylogenetic trend toward increasing fecundity. We find some statistical support for correlations between ecological shifts and shifts in female reproductive strategies. CONCLUSIONS: Because of the short branches at the base of the phylogram, which lead to ecologically diverse lineages, we conclude that much of the adaptive radiation into alternate breeding substrates occurred rapidly, early in the group's evolution in Hawaii. Furthermore, we conclude that this ecological divergence and the correlated changes in ovarian patterns that adapt species to their ecological habitats were contributing factors in the major phyletic branching within the Hawaiian drosophilid fauna.

Adaptation, Physiological↗
PubMed1995

Distribution of mRNA encoding the FA-CHIP water channel in amphibian tissues: effects of salt adaptation.

A water channel, the frog aquaporin-CHIP (FA-CHIP) was recently cloned from Rana esculenta urinary bladder. The 28.9 kDa encoded protein shows 78.8%, 77.4%, 42.4% and 35.6% identity with rat CHIP28, human CHIP28, rat WCH-CD and gamma-TIP, other members of the new transmembrane water channel family (Aquaporin-CHIP). We have now studied membranes from different frog (R. esculenta) organs employing semiquantitative PCR using FA-CHIP specific primers and an internal standard to quantify the PCR products. The FA-CHIP mRNA was abundantly expressed in the frog urinary bladder, skin, lung and gall bladder, while a lower expression was detected in the colon, liver and oviduct. FA-CHIP mRNA was not detected in the frog kidney, erythrocytes and brain but its expression was observed in the toad (Bufo arenarum) urinary bladder and skin, showing that FA-CHIP is probably a general amphibian water channel. Salt acclimation is known to increase the water permeability of frog and toad epithelia. We have now observed that salt acclimation for 1, 3, 4 or 5 days markedly increased skin and urinary bladder FA-CHIP mRNA expression. It is generally accepted that water permeability is controlled in these tissues by the rate of water channel transfer from subapical vesicles (aggrephores) to the apical membrane. Our results indicate that water permeability is also regulated at the level of the FA-CHIP transcription.

Adaptation, Physiological↗
PubMed1995

Water pathways across a reconstituted epithelial barrier formed by Caco-2 cells: effects of medium hypertonicity.

Caco-2 cells, originated in a human colonic cancer, are currently used as model systems to study transepithelial transports. To further characterize their water permeability properties, clone P1 Caco-2 cells were cultured on permeable supports. At confluence, the transepithelial net water movement (Jw), mannitol permeability (Ps), and electrical resistance (R) were simultaneously measured. The observed results were correlated with transmission and freeze-fracture electron microscopy studies and compared with those obtained, in similar experimental conditions, in a typical mammalian epithelial barrier: the rabbit rectum. When the serosal solution was made hypertonic (50 mM polyethylene glycol-PEG), the spontaneously observed secretory Jw rapidly reversed, became absorptive and then stabilized. Simultaneously, the R values dropped and Ps went up. In the case of the rabbit rectal epithelium, a similar treatment did not elicit significant changes in the water permeability during the first 20 min following the osmotic challenge while there was a significant increase in the transepithelial resistance. After exposure to serosal hypertonicity, several morphological modifications developed in the Caco-2 cells: Localized dilations in the intercellular spaces and vacuoles in the cytoplasm appeared. Nevertheless, most cells remained in contact and no evidence of cell shrinking was observed. Simultaneously, the tight-junction structure was more or less disorganized. The filament network lost its sharpness and "omega" figures appeared, bordering the intercellular spaces. In some cases the tight-junction network was completely disrupted. In the case of the rabbit rectum the structural modifications were completely different: Serosal hypertonicity rapidly induced cell shrinking and the opening of the intercellular spaces, with no noticeable change in the tight-junction structure.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Failure of technetium-99m hexamethylpropylene amine oxime leukocyte scintigraphy in the evaluation of children with suspected appendicitis.

To determine the accuracy and reliability of a labeled leukocyte imaging technique in the early diagnosis of pediatric appendicitis, we prospectively studied patients presenting to the pediatric emergency department with abdominal pain suggestive of appendicitis. Patients scheduled for urgent laparotomy were excluded, as were postmenarchal females. Blinded interpretations by two independent radiologists were compared with surgical findings, if managed operatively, or with discharge diagnoses and three week follow-up, if managed medically. Twenty-three children underwent technetium-99m hexamethylpropylene amine oxime (HMPAO) leukocyte scintigraphy. Seven had pathologically proven appendicitis, with false negative interpretations made in three and five cases by the two radiologists. Sixteen patients had prompt resolution of symptoms; however, scintigraphic abnormalities were identified in 10 and seven cases by the two radiologists. Resulting sensitivity, depending on the individual reader, ranged from 29 to 57%, with specificity 38 to 56%, positive predictive value 22 to 29%, negative predictive value 64 to 67%, and accuracy 43 to 48%. Interrater reliability for agreement on the scintigraphic diagnosis of appendicitis was poor (kappa = 0.38). Technetium-99m HMPAO leukocyte scintigraphy was neither accurate nor reliable as a diagnostic tool in a subgroup of pediatric patients with an initial clinical presentation equivocal for appendicitis. This finding contradicts previously published experience using similar scintigraphic techniques.

Abdominal Pain↗
PubMed1995

mRNA from frog corneal epithelium increases water permeability in Xenopus oocytes.

PURPOSE: To investigate the existence of a water channel in the frog corneal epithelium by studying the osmotic water permeability (Pf) of Xenopus oocytes expressing the mRNA message from frog corneal epithelium. METHODS: Total RNA was obtained from corneal epithelium by a single-step phase separation method, and poly A+ RNA was isolated using oligo-dT columns. This mRNA was injected into the oocytes. After a 48-hour incubation, oocyte volume changes elicited by a hypoosmotic solution were measured with a computerized video system. RESULTS: Oocytes injected with 50 nl mRNA (1 microgram/microliter) showed a significant increase in Pf compared to water-injected controls (8.4 +/- 1.5 to 17.5 +/- 1.9 cm.sec-1 x 10(-4), P < 0.005). mRNA-injected oocytes exposed to a higher external [Cl-] showed a heightened permeability. Furthermore, Pf of oocytes exposed to a solution containing the recognized water-channel blocker HgCl2 was significantly lower than the Pf of mRNA-injected oocytes not exposed to HgCl2. CONCLUSIONS: Evidence was found for a water channel in the frog corneal epithelium because oocytes injected with the epithelial mRNA manifested increased water permeability. The increase in water permeability was larger in the presence of external Cl- and was inhibited by HgCl2. This finding correlates with measurements of Pf in the intact epithelium in which apical Cl- induced an increase in transepithelial water permeability prevented by HgCl2.

Animals↗
PubMed1994

Water permeability properties of the ovarian oocytes from Bufo arenarum and Xenopus laevis: a comparative study.

The water permeability properties of ovarian oocytes from Xenopus laevis and Bufo arenarum, a toad species found in the Buenos Aires region, were studied. We report that: (i) the water osmotic permeability (Pf, cm/sec x 10(-4)) was significantly higher in Bufo (6 degrees C = 12.3 +/- 2.4; 18 degrees C = 20.8 +/- 4.8) than in Xenopus oocytes (6 degrees C = 5.3 +/- 0.3; 18 degrees C = 6.2 +/- 1.6). The corresponding water diffusion permeability values (Pd, cm/sec x 10(-4)) were: Xenopus = 2.3 +/- 0.3 (6 degrees C) and 4.8 +/- 0.7 (18 degrees C); Bufo = 2.7 +/- 0.4 (6 degrees C) and 6.0 +/- 0.5 (18 degrees C). (ii) Amphotericin B increased the Pf and Pd values. The observed delta Pf/delta Pd ratio was not significantly different from the expected results (n = 3), after amphotericin B incorporation in both species. This means that the influence of unstirred layers and other potential artifactual compounds did not significantly affect our experimental results. (iii) Preincubation with gramicidin during 12 hr induced a clear increase in the oocyte volume. After that, a hypotonic shock only slightly increased the oocyte volume. Conversely, a hypertonic challenge induced a volume change significantly higher than the one observed in control conditions. (iv) Mercury ions did not affect the osmotic permeability in Xenopus oocytes but clearly inhibited, in a reversible way, the osmotic permeability in oocytes from B. arenarum. (v) Mercury ions did not reduce Pd values in either species.(ABSTRACT TRUNCATED AT 250 WORDS)

Amphotericin B↗
PubMed1994

[Psychological dynamics in adolescence regarding death and suicide].

The authors try to analyse the idea of death and suicide in the adolescent and in order to face the psychological dynamics underlying these experiences. Therefore the differences between adolescential vitality and the separation-loss feelings emerge, between the need for autonomy and the search for identification patterns that are peculiar to this part of vital cycle. The autonomy and freedom search seems to pass delusively through the manipulation of the idea of death, to face a theme reserved to adults gives adolescent omnipotence feelings, assuring him at the same time against anguish. In the second part the authors report the clinical case of a boy who attempted suicide turce and who is under observation in the Department of Mental Health.

Adolescent↗
PubMed1993

Fura-2 transport in toad urinary bladder epithelium: effects of antidiuretic hormone, colchicine and osmotic gradients.

Fluorescence is transferred across the toad urinary bladder when fura-2/AM is added to the mucosal or serosal sides of the epithelium. It was now observed that: (1) Oxytocin (20 nM, serosal) increased fluorescence transfer from the mucosal to the serosal but not from the serosal to the mucosal baths. The ratio between the fluorescence intensities recorded with excitation wavelengths of 340 and 380 nm indicates that the calcium sensitive probe (free fura-2) was transferred to the serosal but not to the mucosal compartment by an oxytocin sensitive transport. (2) Preincubation with probenecid did not change fluorescence transfer in basal conditions but significantly reduced the oxytocin induced increase in free fura-2 transport. (3) Fluorescence accumulation inside the tissue was strongly reduced by oxytocin, but only when fura-2/AM was added to the mucosal side. (4) An osmotic gradient, in the presence of oxytocin, further increased the transfer of fluorescence at 380 nm but not at 340 nm. This indicated that the transfer of a calcium-insensitive fraction was being stimulated. (5) Preincubation with colchicine strongly inhibited fluorescence transfer across the tissue, at both 340 and 380 nm (the 340/380 ratio did not change). (6) Tissue accumulation was increased by colchicine. (7) Vanadate did not inhibit fura-2 transfer in the toad urinary bladder. We conclude that intracellularly-generated free fura-2 is only transported across the basolateral border, and that this transfer is stimulated by ADH. The calcium-insensitive fraction is transferred by a temperature-dependent process, sensitive to an osmotic gradient and colchicine.

Animals↗