Biomedical subjects

G Amodeo

Publications and source records attributed to G Amodeo.

11 recordsLinked to original sources

PubMed2004

Polymorphonuclear leukocyte: rheology, metabolism and integrin pattern in vascular atherosclerotic disease and in type 2 diabetes mellitus.

Leukocytes, and in particular polymorphonuclear cells (PMN), play a role in the organ injury that characterizes the progression of vascular atherosclerotic disease (VAD) and diabetes mellitus (DM). We enrolled subjects with VAD, subjects with type 2 DM (DM2) and subjects with VAD and DM2. We evaluated the initial relative flow rate (IRFR) of PMN, using the St. George Filtrometer, the PMN membrane fluidity, labelling intact PMN cells with the fluorescent probe 1.4-(trimethylamino)-phenyl-4-phenylhexatriene (TMA-DPH), the PMN cytosolic Ca2+ content marking the cells with the fluorescent probe Fura 2-AM and the PMN integrin profile using the flow cytofluorimetry. All these evaluations were effected at baseline and after activation with 4-phorbol-12-myristate-13-acetate (PMA). At baseline and after activation the IRFR did not distinguish normal subjects from any group of patients. The PMN membrane fluidity at baseline differentiated only normal from DM2 subjects, while after activation no significant variation of this parameter was observed in normal, VAD, DM2 and VAD-DM2 subjects. The PMN cytosolic Ca2+ content, at baseline, discriminated only normal from VAD subjects with DM2, while after activation a significant increase of this parameter was evident in DM2 subjects and in VAD subjects with DM2. Regarding the PMN integrin pattern we observed, at baseline and after activation, a complex and non-univocal behaviour. In conclusion, the PMN rheological and metabolic pattern found in these groups of patients showed only small functional alterations while the integrin pattern was significantly different from that of normal subjects and added specific elements which may have potential therapeutical implications.

Arteriosclerosis↗

PubMed2003

Volumetric and ionic responses of goldfish hepatocytes to anisotonic exposure and energetic limitation.

The relationship between cell volume and K(+) transmembrane fluxes of goldfish (Carassius auratus) hepatocytes exposed to anisotonic conditions or energetic limitation was studied and compared with the response of hepatocytes from trout (Oncorhynchus mykiss) and rat (Rattus rattus). Cell volume was studied by video- and fluorescence microscopy, while K(+) fluxes were assessed by measuring unidirectional (86)Rb(+) fluxes. In trout and rat hepatocytes, hyposmotic (180 mosmoll(-1)) exposure at pH 7.45 caused cell swelling followed by a regulatory volume decrease (RVD), a response reported to be mediated by net efflux of KCl and osmotically obliged water. By contrast, goldfish hepatocytes swelled but showed no RVD under these conditions. Although in goldfish hepatocytes a net ((86)Rb(+))K(+) efflux could be activated by N-ethylmaleimide, this flux was not, or only partially, activated by hyposmotic swelling (120-180 mosmoll(-1)). Blockage of glycolysis by iodoacetic acid (IAA) did not alter cell volume in goldfish hepatocytes, whereas in the presence of cyanide (CN(-)), an inhibitor of oxidative phosphorylation, or CN(-) plus IAA (CN(-)+IAA), cell volume decreased by 3-7%. Although in goldfish hepatocytes, energetic limitation had no effect on ((86)Rb(+))K(+) efflux, ((86)Rb(+))K(+) influx decreased by 57-66% in the presence of CN(-) and CN(-)+IAA but was not significantly altered by IAA alone. Intracellular K(+) loss after 20 min of exposure to CN(-) and CN(-)+IAA amounted to only 3% of the total intracellular K(+). Collectively, these observations suggest that goldfish hepatocytes, unlike hepatocytes of anoxia-intolerant species, avoid a decoupling of transmembrane K(+) fluxes in response to an osmotic challenge. This may underlie both the inability of swollen cells to undergo RVD but also the capability of anoxic cells to maintain intracellular K(+) concentrations that are almost unaltered, thereby prolonging cell survival.

Anaerobiosis↗

PubMed2002

Protoplasmic pH modifies water and solute transfer in beta vulgaris root vacuoles.

Volume changes were studied in Beta vulgaris storage root vacuoles, using video microscopy, when exposed to hypotonic conditions. The osmotic gradient was either step-applied or progressively imposed in perfusion experiments. Preincubation at low pH (6.6) or with HgCl2 strongly reduced the vacuoles' water permeability, measured in step experiments. Furthermore, the volumetric response depended on the rate with which the aniso-osmotic condition was established. In perfusion experiments a "plateau value" (osmotic equilibrium or steady-state volume value) was observed, which was significantly lower than the theoretically expected one. Furthermore, if vacuoles were preincubated in presence of HgCl2 or at low pH and then the hypo-osmotic challenge was applied in perfusion experiments, a still lower "plateau value" was observed. This reduction was concentration-dependent and completely reversible. In these conditions, when HgCl2 concentration was 300 mM or medium pH was 6.6, the volume change was abolished. In other experiments, when urea iso-osmotically replaced mannitol, a reversible, pH-dependent volumetric response was observed. These results can be interpreted accepting that 1) mercury-sensitive water channels, present in the studied structure, were blocked by low pH during the hypo-osmotic challenge; 2) modification of water permeability prevents excessive swelling during the osmotic shock; 3) the effectiveness of this last mechanism depended on the osmotic challenge rate; and 4) additionally, urea reflection coefficients were also modified by reduced medium pH.

Beta vulgaris↗

PubMed1999

Functional characterization and localization of AQP3 in the human colon.

Water channels or aquaporins (AQPs) have been identified in a large variety of tissues. Nevertheless, their role in the human gastrointestinal tract, where their action is essential for the reabsorption and secretion of water and electrolytes, is still unclear. The purpose of the present study was to investigate the structure and function of water channels expressed in the human colon. A cDNA fragment of about 420 bp with a 98% identity to human AQP3 was amplified from human stomach, small intestine and colon by reverse transcription polymerase chain reaction (RT-PCR) and a transcript of 2.2 kb was expressed more abundantly in colon than in jejunum, ileum and stomach as indicated by Northern blots. Expression of mRNA from the colon of adults and children but not from other gastrointestinal regions in Xenopus oocytes enhanced the osmotic water permeability, and the urea and glycerol transport in a manner sensitive to an antisense AQP3 oligonucleotide, indicating the presence of functional AQP3. Immunocytochemistry and immunofluorescence studies in human colon revealed that the AQP3 protein is restricted to the villus epithelial cells. The immunostaining within these cells was more intense in the apical than in the basolateral membranes. The presence of AQP3 in villus epithelial cells suggests that AQP3 is implicated in water absorption across human colonic surface cells.

Adult↗

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

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↗

PubMed1992

Vanadate inhibits blue light-stimulated swelling of vicia guard cell protoplasts.

When supplied under low chloride concentrations, vanadate inhibits the blue light-stimulated swelling of Vicia faba L. guard cell protoplasts in a dose-dependent fashion. The volume of guard cell protoplasts incubated in 10 mm K-imino-diacetic acid, 0.4 m mannitol, and 1 mm CaCl(2) remained essentially constant under 1000 mumol m(-2) s(-1) red light, but increased an average of 27% after 8 min of the addition of 50 mumol m(-2) s(-1) blue light to the background red light. At 500 mum, vanadate completely inhibits the response to blue light. Vanadate also inhibits the swelling of guard cell protoplasts stimulated by the H(+)-ATPase agonist fusicoccin. The vanadate sensitivity of the blue light-stimulated swelling implicates a proton-pumping ATPase as a component of the sensory transduction of blue light in guard cells.

Journal Article↗

PubMed1988

Concomitant gonadotropin-releasing hormone agonist and menotropin treatment for the synchronized induction of multiple follicles.

In an effort to overcome possible interference by endogenous gonadotropin-ovarian hormone dynamics, desensitization of the pituitary gonadotropins by a gonadotropin-releasing hormone agonist (GnRHa) was achieved in 12 women with repeatedly failed attempts at multiple follicular stimulation. Eight women were scheduled for in vitro fertilization (IVF) and embryo transfer (ET), and 4 for gamete intrafallopian transfer (GIFT). Stimulation failure was characterized by premature luteinization, poor estradiol (E2) response, or inadequate follicular growth. The agonist was administered by nasal spray 500 to 600 micrograms/day beginning on days 21 to 23 of the menstrual cycle. A rapid desensitization occurred by 7.6 +/- 0.6 days (mean +/- standard error [SE]) following the initial dose. Gonadotropin stimulation was begun when pituitary and ovarian suppression was judged to be adequate. In response to gonadotropin stimulation, a continuous rise of E2 was observed in all patients with a mean of 989 +/- 46 pg/ml on the day of hCG. A cohort of synchronized follicles was recruited and matured. The mean number of growing follicles per patient was significantly higher (P less than 0.0001) in combined therapy than in previously failed cycles (8.0 +/- 0.3 versus 3.2 +/- 0.1). All the patients underwent oocyte retrieval and 94.3% of the harvested oocytes were preovulatory. A high fertilization rate (89.7%) of the inseminated oocytes occurred in IVF patients.

Adult↗

PubMedDate not supplied

Varicocele and puberty. A transversal and longitudinal survey.

The interest for varicocele in the determination of male infertility has increased during the last decades. Most researchers consider varicocele as the primary cause of male infertility, but recently another group of authors give it a secondary role in the alteration of spermatogenesis. We think that the major part of the controversy depends on an absence of a systematic approach to the problem. We give a primary importance to an accurate epidemiological evaluation which consists in a transversal and longitudinal survey of male subjects in puberal age. Our data show that left varicocele is practically inexsistent before the onset of puberty; the percentage incidence of this alteration increases progressively with puberal maturity and the tends to decrease slightly when maturity is complete. By correlating this pathology with puberty we can obtain more precise informations than when it is correlated to the regestrated age. The young patients who result suffering from varicocele, must be controlled carefully and periodically for the evaluation of the period and the opportunity of a therapeutic treatment.

Adolescent↗

PubMedDate not supplied

Induction of ovulation in normo-androgenic women, affected by primary hypothalamic amenorrhea, with chronic pulsatile administration of GnRH, using an automatic portable pump (Zyklomat).

Pulsatile administration of GnRH appears to be the most rational and physiological treatment of infertility in patients affected by hypothalamic amenorrhea. The authors conclude that the results obtained with this method of treatment in patients with severe hypothalamic amenorrhea suggest that the choice of pulsatile GnRH therapy is an effective and practical method for induction of ovulation.

Adult↗

PubMedDate not supplied

One year's experience with the GIFT method.

From January 1985 to December 1985 we have performed 83 GIFTS for various indications such as unexplained infertility, immunological problems, endometriosis, male factor, fimbrial pathology. In 82 women out of 83, oocytes and sperm have been transferred and 31 pregnancies (37.8%) have been obtained. Twelve women have delivered 17 babies; 11 pregnancies are ongoing, 7 have been interrupted by an abortion and 1 by a tubal pregnancy. The present and future roles of GIFT in the treatment of infertility is discussed.

Adult↗