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Biomedical subjects

A Antonucci

Publications and source records attributed to A Antonucci.

At least 19 recordsLinked to original sources
PubMed2001

Formation of nitrotyrosine by methylene blue photosensitized oxidation of tyrosine in the presence of nitrite.

Methylene blue photosensitized oxidation of tyrosine in the presence of nitrite produces 3-nitrotyrosine, with maximum yield at pH 6. The formation of 3-nitrotyrosine requires oxygen and increases using deuterium oxide as solvent, suggesting the involvement of singlet oxygen in the reaction. The detection of dityrosine as an additional reaction product suggests that the first step in the interaction of tyrosine with singlet oxygen generates tyrosyl radicals which can dimerize to form dityrosine or react with a nitrite-derived species to produce 3-nitrotyrosine. Although the chemical identity of the nitrating species has not been established, the possible generation of nitrogen dioxide (*NO(2)) by indirect oxidation of nitrite by intermediately produced tyrosyl radical, via electron transfer, is proposed. One important implication of the results of this study is that the oxidation of tyrosine by singlet oxygen in the presence of nitrite may represent an alternative or additional pathway of 3-nitrotyrosine formation of potential importance in oxidative injures such as during inflammatory processes.

Animals↗
PubMed2001

Histochemical and biochemical analysis of phospholipase C isoforms in normal human gastric mucosa cells.

The expression and activity of PIP2-specific phospholipase C (PLC) in healthy human gastric mucosa cells were investigated by means of Western blotting, immunohistochemistry and in vitro activity assays. The results provide direct evidence for an almost exclusive expression of the PLC beta family and at the same time supply a cellular cartography of each represented isoform of this family. In this context, the putative roles of each isoform in the signaling events regulating the gastric mucosa metabolic machinery are discussed. These data provide a unique map of the specific expression and cellular distribution of the most represented PLC isoforms in healthy human gastric mucosa cells, which may constitute a reference point in future studies aimed at highlighting possible cytochemical and biochemical hallmarks of metaplastic or malignant transformation.

Blotting, Western↗
PubMed2001

Mitochondrial perturbations and oxidant stress in lymphocytes from patients undergoing surgery and general anesthesia.

BACKGROUND: Previous studies have shown that a profound suppression of immune function transiently occurs in patients who undergo surgery under general anesthesia. The decline in the absolute counts of peripheral blood lymphocytes constitutes a major factor accounting for this immune defect, and recent evidence indicates that apoptosis plays a crucial role in determining postsurgical lymphocytopenia. HYPOTHESIS: An altered oxidation-reduction status of mitochondria may contribute through apoptosis to the loss of lymphocytes following surgical trauma and general anesthesia. DESIGN: We studied 16 patients with American Society of Anesthesiologists' physical status I or II who underwent elective surgery under general anesthesia. The data were collected prospectively. SETTING: University hospital. MAIN OUTCOME MEASURES: Samples of peripheral blood were drawn on the day before surgery and at 24 and 96 hours after the operation. Following lymphocyte isolation, the mitochondrial transmembrane potential was assessed by flow cytometry using 3,3'-dihexylocarbo-cyanine iodide, and stains with hydroethidine and 2'-7'-dichlorofluorescein diacetate were used to determine the generation of reactive oxygen species. The labeling of lymphocytes with monobromobimane was used to assess the presence of reduced glutathione. RESULTS: At 24 hours after surgery, we detected a significantly elevated frequency of peripheral blood lymphocytes (P =.002), which incorporated low levels of 3,3'-dihexylocarbo-cyanine iodide, compared with the preoperative period. At this same time point, the frequency of lymphocytes with the hydroethidine- and 2'-7'-dichlorofluorescein diacetate-positive phenotype was elevated compared with baseline levels. Conversely, at 24 hours after surgery, the frequency of cells that stained positive for glutathione was strongly decreased compared with preoperative values. Overall measurements returned to the baseline levels at 96 hours after surgery. CONCLUSION: The strict association we observed between the overproduction of reactive oxygen species and the disruption of the mitochondrial transmembrane potential supports the view that alterations in mitochondrial energy metabolism, paralleled by the presence of a pro-oxidant oxidation-reduction status, could be involved in the accelerated apoptotic loss of lymphocytes following surgical trauma and general anesthesia.

Anesthesia, General↗
PubMed2001

Phospholipase C delta2 expression characterizes the neoplastic transformation of the human gastric mucosa.

The expression, cellular distribution, and activity of PIP(2)-specific phospholipase C (PLC) in healthy human gastric-mucosa cells have been recently studied in our laboratories and a direct evidence for an almost exclusive expression of PLC beta isoforms, with the exception of PLC beta4, has been provided. These results addressed our attention to possible modification of PLC expression and activity during neoplastic transformation of the human gastric mucosa. In the present article we present results indicating that PLC delta2 is markedly expressed in type II intestinal metaplasia and in the adenocarcinoma whereas traces of other PLC isoforms were sometime detected. Interestingly, we found that type I intestinal metaplasia was in the majority of the cases PLC delta2-negative, but when expressed, this type of metaplasia generally considered as benignant, always evolved toward neoplastic transformation. These results therefore readdress the question of surveillance of the patients with type I intestinal metaplasia and suggest that PLC delta2 expression might be a possible marker of gastric malignant transformation.

Adenocarcinoma↗
PubMed2001

Circulating neutrophils exhibit enhanced apoptosis associated with mitochondrial dysfunctions after surgery under general anaesthesia.

BACKGROUND: Evidence suggests that apoptosis plays a main role in the postoperative changes detected in the polymorphonuclear neutrophil (PMN) population. Furthermore, recent studies have demonstrated that mitochondrial alterations constitute critical events of the apoptotic cascade. In this study we investigated whether apoptosis among neutrophils taken from patients undergoing surgical trauma could be associated with perturbation of mitochondrial transmembrane potential (deltapsim) and/or exaggerated production of mitochondrial reactive oxygen species (ROS). METHODS: Twenty-seven patients undergoing elective surgery under general anaesthesia were enrolled in the study. Peripheral blood samples were drawn one day before the operation and at 12 and 24 h after surgery. Apoptosis rate was assessed by staining neutrophils with 7-amino-actinomycin D (7-AAD) and by analysis by a FACScan flow cytometer. In order to evaluate deltapsim, cells were exposed to 3,3-dihexyloxacarbocyanine iodide [DiOC6(3)]; intracellular ROS was measured by means of hydroethidine (HE) and 2,7-diclorofluorescein diacetate (DCFH-DA), followed by analysis on a cytofluorometer. RESULTS: At 12 h following surgery we observed a significantly (P<0.05) increased frequency of apoptotic PMNs compared to that preoperatively (30.79+/-3.68% vs 7.40+/-0.69%). At this same time-point, the rate of neutrophils stained with HE, DCFH-DA and [DiOC6(3)] were significantly (P<0.05) higher compared to baseline (51.05+/-5.44%, 50.58+/-5.84% and 55.31+/-4.33% vs 20.17+/-2.38%, 19.59+/-2.03 and 25.43+/-2.71% respectively). Overall measurements returned to the preoperative values 24 h after surgery. CONCLUSION: These data suggest that surgery under general anaesthesia triggers in the immediate postoperative period pathways of PMN accelerated apoptosis associated with significant alterations in mitochondrial function.

Aged↗
PubMed2001

In situ splitting of a liver with middle hepatic vein anomaly.

In situ liver splitting provides a way to expand the graft pool, minimize cold ischemia time, and improve hemostasis at the cut surface of the graft. Vascular anomalies of the liver may make the splitting procedure very difficult or even impossible to perform. The in situ splitting procedure, performed on a liver with a middle hepatic vein (MHV) anomaly, is described here. The MHV drained directly into the segment III vein within the hepatic parenchyma instead of draining into the left hepatic vein to form the common trunk. In situ splitting was performed during multiorgan procurement from a 33-year-old man who died of isolated cerebral trauma. The MHV was reconstructed on the back table to secure right graft venous drainage using an iliac vein graft. The resultant right graft, segments I and IV to VIII, and left graft, segments II and III, were transplanted successfully into an adult and a child, respectively. The 2 transplant recipients are currently alive with normal hepatic function 20 months after transplantation.

Adult↗
PubMed2001

Interleukin-10 and apoptotic death of circulating lymphocytes in surgical/anesthesia trauma.

OBJECTIVE: To examine the relationship between circulating interleukin-10 (IL-10) and the occurrence of lymphocyte apoptosis after surgical/anesthesia trauma. METHODS: Data were collected prospectively on 18 adult patients undergoing elective major surgery. Blood sampling for assessment of lymphocyte apoptosis and IL-10 levels was performed on the day before surgery (t(0)) and at 24 and 96 hours after operation (t(1) and t(2), respectively). After lymphocyte isolation, quantification of apoptosis was made by staining apoptotic cells with 7-amino-actinomycin D. Plasma IL-10 concentrations were measured using enzyme-linked immunosorbent assay. RESULTS: A significantly increased frequency of apoptotic CD4(+) and CD8(+) cells (p < 0.05) was observed at t1 measurement (8.10% +/- 0.58% and 12.21% +/- 1.47% for CD4(+) and CD8(+), respectively) compared with preoperative values (1.53% +/- 0.38% and 1.32% +/- 0.45% for CD4(+) and CD8(+), respectively). Plasma IL-10 levels showed a significant elevation at both t(1) and t(2) times, peaking at t(1). At t(1), IL-10 levels were correlated with the frequency of CD4(+) and CD8(+) apoptotic lymphocytes (r = 0.78, p = 0.0005 for IL-10 vs. apoptotic CD4(+); r = 0.71, p = 0.003 for IL-10 vs. apoptotic CD8(+)). CONCLUSION: Surgical trauma is associated with a significant but transient increase in lymphocyte commitment to apoptosis and IL-10 production. The exact relationship linking the overproduction of IL-10 with lymphocyte apoptosis after a surgical operation is still elusive and requires further investigation.

Adult↗
PubMed2001

Ultrastructural modifications and phosphatidylinositol-3-kinase expression and activity in myocardial tissue deriving from rats in different experimental conditions.

Oxygen supply is essential in the maintenance of the physiological cell metabolism. In fact, both lower and higher O2 concentrations induce modifications of the enzymatic activity of the cell which determine, in turn, morphological changes at nuclear and cytoplasmic level. Among the molecules involved in the maintenance of the cellular homeostasis, the signal transduction pathway PI-3-kinase/AKT-1 should be included. Here we suggest a relationship between the modulation of this pathway and the morphological modifications occurring "in vivo" in myocardial tissue upon hypoxic and hyperoxic stress. In particular, down regulation of this pathway, which when activated is known to deliver an anti-apoptotic signal, is concomitant to the maintenance of the apoptotic events occurring in these cells in response to oxidative stresses.

Animals↗
PubMed2000

Methylene blue photosensitized oxidation of cysteine sulfinic acid and other sulfinates: the involvement of singlet oxygen and the azide paradox.

The methylene blue photosensitized oxidation of cysteine sulfinic acid is investigated. Enhancement of the oxygen consumption rate in deuterium oxide suggests the involvement of singlet oxygen ((1)O(2)) in oxidation. Addition of the (1)O(2) quencher azide produced an unusual enhancement of the oxidation rate of all the sulfinates assayed. It is assumed that azide works as a one-electron carrier between (1)O(2) and the sulfur compounds. Analyses of the products indicate that the photochemical oxidation of cysteine sulfinic acid proceeds through two simultaneous mechanisms. The Type II (singlet oxygen) mechanism is responsible for oxidation of the sulfinic group to the sulfonic group with production of cysteic acid, stable to the photooxidation system, whereas the Type I (electron transfer) mechanism is involved in the degradation of cysteine sulfinic acid to acetaldehyde. Other products detected were ammonia, sulfate, and hydrogen peroxide which account for the degradation of cysteine sulfinic acid and for the excess of oxygen consumption detected during the oxidative reaction.

Aerobiosis↗
PubMed2000

Apoptosis and surgical trauma: dysregulated expression of death and survival factors on peripheral lymphocytes.

BACKGROUND: Surgery and anesthesia cause depression of cell-mediated immunity in the postoperative period, including a reduction in the numbers of circulating lymphocytes. It has been claimed that this immunosuppression is associated with an increased incidence of postoperative infections. HYPOTHESIS: Lymphocytopenia following surgical trauma depends on a dysregulated expression of death/and survival factors associated with apoptosis that, in turn, interferes with the occurrence of postsurgical infections. DESIGN: Fifteen subjects undergoing elective surgery under general anesthesia entered the study. The data of the patients who had infections during the postoperative outcome were compared with the data of those who did not. The data were collected prospectively. MAIN OUTCOME MEASURES: Peripheral blood samples were drawn before the operation, and 24 hours and 96 hours after the operation. Lymphocytes were isolated and examined for quantification and phenotypic analysis of apoptosis using the 7-amino-actinomycin D method, as well as for Fas and Fas ligand, interleukin 1-converting enzyme p20/caspase-1, Bcl-2, and p35 expression. The rate of apoptotic cells was correlated with the incidence of postoperative infections. SETTING: University hospital. RESULTS: Twenty-four hours after surgery, CD4(+) and CD8(+) cells exhibited a significantly higher frequency of apoptosis as well as of Fas and Fas ligand and interleukin 1-converting enzyme p20/caspase-1 expressions than preoperatively. This increase was paralleled by a significant down-regulation of antiapoptotic factors such as Bcl-2. However, the expression of the proapoptotic factor p35 was reduced. In addition, we found a relationship between the rate of the apoptotic CD8(+) subset and the occurrence of infectious complications during the postoperative course. At 96 hours after surgery, the variables studied returned to the baseline levels. CONCLUSIONS: In the early postoperative period, surgical trauma under general anesthesia induces an intracellular perturbation on peripheral lymphocytes, resulting in both up-regulation of death-signaling factors and down-regulation of survival-signaling factors. The increased apoptosis of CD8(+) lymphocytes, but not of CD4(+) cells, seemed to be associated with a greater risk of postsurgical infections.

Analysis of Variance↗
PubMed2000

Identification of an oxidation product of aminoethylcysteine ketimine dimer.

In continuation of our previous work dedicated to the detection of the oxidation products of aminoethylcysteine ketimine dimer by oxygen reactive species, we give here data for the identification of the alpha, beta unsaturated sulfoxide as the main product of interaction of the dimer with H2O2. Identification has been done on the basis of mass spectrometry and NMR analyses of the product isolated by preparative chromatography.

Amino Acids, Sulfur↗
PubMed1999

Identification of aminoethylcysteine ketimine decarboxylated dimer in human plasma.

Aminoethylcysteine ketimine decarboxylated dimer (AECK-DD) is a natural sulfur-containing tricyclic compound detected, until now, in human urine and bovine cerebellum. Recently, the antioxidant properties of this compound, and particularly its protective effect on the in vitro oxidation of low-density lipoproteins, have been demonstrated. In this paper, the identification of AECK-DD in human plasma by means of gas chromatography, high-performance liquid chromatography and gas chromatography-mass spectrometry, performed after a simple and fast purification procedure, is reported.

Chromatography, Gas↗
PubMed1999

Oxidation of hypotaurine to taurine with photochemically generated singlet oxygen: the effect of azide.

Hypotaurine is oxidized to taurine by singlet oxygen (1O2) generated with methylene blue used as a photosensitizer. The oxidation rate increases in the presence of deuterium oxide as expected for the involvement of 1O2. Addition of the 1O2 quencher azide also produced an activating effect in contrast with the expected inhibition. Azidyl radicals produced by the oxidation of azide by the horseradish peroxidase/hydrogen peroxide system stimulate the oxidation of the added hypotaurine. It is concluded that azide competes with hypotaurine for 1O2 generating the azidyl radical which is a strong one-electron oxidant transfer of the radical to hypotaurine. The hypotaurine radical is then converted into taurine, possibly through the disulfone intermediate. Formation of the sulfonic hydroperoxide is the possible intermediate in the absence of azide. The finding that the azidyl radical efficiently oxidizes hypotaurine to its metabolic product taurine raises the expectation of hypotaurine being a valuable scavenger of endogenous and exogenous radicals.

Azides↗
PubMed1999

Ceramide concentrations in septic patients: a possible marker of multiple organ dysfunction syndrome.

OBJECTIVES: To investigate the concentrations of mononuclear cell-associated ceramide and serum tumor necrosis factor-alpha (TNF-alpha) in patients with sepsis and to assess their predictive value for the development of multiple organ dysfunction syndrome (MODS). DESIGN: Prospective, cohort study. SETTING: Intensive care unit and two research laboratories at a university hospital. PATIENTS: Twenty-three adult patients admitted to an intensive care unit meeting the criteria for diagnosis of sepsis. INTERVENTIONS: Blood samples were collected at the time when diagnosis of sepsis was made. MEASUREMENTS AND MAIN RESULTS: Mononuclear cell-associated ceramide and serum TNF-alpha were significantly elevated in the samples from the septic patients compared with the control individuals (318.01+/-270.15 pmol/10(6) cells vs. 99.90+/-52.75 pmol/10(6) cells; p<.001, and 28.52+/-18.77 pg/mL vs. 10.43+/-3.37 pg/mL; p<.0001, respectively), and a direct correlation linked ceramide and TNF-alpha concentrations (r2 = .90, p<.00001). In the septic patients who went on to develop MODS, ceramide and TNF-alpha were significantly higher compared with the no MODS patients (489.22+/-264.93 pmol/10(6) cells vs. 131.23+/-99.02 pmol/10(6) cells; p<.0001, and 40.96+/-18 pg/mL vs. 14.95+/-5.60 pg/mL; p<.001, respectively). The receiver operating characteristic curves demonstrated that both TNF-alpha and ceramide were prognostic of MODS, but ceramide concentrations were more efficient predictors. CONCLUSIONS: These observations suggest that mononuclear cells of peripheral blood from patients with sepsis are committed to undergo apoptosis, because there is evidence that ceramide acts as an endogenous mediator of apoptosis. The strong correlation we found between cell-associated ceramide and serum TNF-alpha supports the hypothesis that this cytokine plays an important role in activating the sphingomyelin pathway and ceramide generation in patients with sepsis. In addition, this study provides evidence that consistent concentrations of mononuclear cell-associated ceramide may predict progression toward MODS in septic patients.

Adult↗
PubMed1999

General anesthesia mode does not influence endocrine or immunologic profile after open or laparoscopic cholecystectomy.

To verify the impact on stress response and the influence of anesthesia on endocrine/immunologic changes, we have investigated the plasma level of norepinephrine, cortisol, TNFalpha, and IL-6 in 46 patients scheduled for laparotomy and laparoscopic cholecystectomy at 2, 6, 12, and 24 h after the operation. Among subjects who underwent open approach, 9 received fentanyl anesthesia and 13 received isoflurane anesthesia. In the laparoscopy group, 14 patients were given fentanyl anesthesia and 10 were given isoflurane anesthesia. The results obtained confirmed that laparoscopic cholecystectomy is associated with a lesser immunoendocrine response, and the two anesthesia models do not interfere with plasma changes of the assessed hormones and cytokines.

Anesthesia, General↗