A Novel Panel of Serum Biomarkers for MPM Diagnosis.

Exposure to asbestos is the main cause of malignant pleural mesothelioma (MPM), a highly aggressive cancer of the pleura. Since the only tools for early detection are based on radiological tests, some authors focused on serum markers (i.e., mesothelin). The aim of this study was the evaluation of new serum biomarkers to be used individually or in combination, in order to improve the outcome of patients whose disease would be diagnosed at an earlier stage. Serum and plasma were available from 43 subjects previously exposed to asbestos and 27 MPM patients, all being epithelioid type. All the new markers found differentially expressed in MPM and healthy subjects, by proteomic and genomic approaches, have been validated in the serum by the use of specific ELISA. The combined approach, using tools of genomics and proteomics, is found to be highly innovative for this type of disease and led to the identification of new serum markers in the diagnosis of MPM. These results, if confirmed in a larger series, may have a strong impact in this area, because early detection of this cancer in people at high risk could significantly improve the course of the disease and the clinical approach to an individualized therapy.

Pregnancy outcome following maternal exposure to statins: a multicentre prospective study.

OBJECTIVE: This contribution addresses the risk associated with exposure to statins during pregnancy. DESIGN: Multicentre observational prospective controlled study. SETTING: European Network of Teratology Information Services. POPULATION: Pregnant women who contacted one of 11 participating centres, seeking advice about exposure to statins during pregnancy, or to agents known to be nonteratogenic. METHODS: Pregnancies exposed during first trimester to statins were followed up prospectively, and their outcomes were compared with a matched control group. MAIN OUTCOME MEASURES: Rates of major birth defects, live births, miscarriages, elective terminations, preterm deliveries and gestational age and birthweight at delivery. RESULTS: We collected observations from 249 exposed pregnancies and 249 controls. The difference in the rate of major birth defects between the statin-exposed and the control groups was small and statistically nonsignificant (4.1% versus 2.7% odds ratio [OR] 1.5; 95% confidence interval [95% CI] 0.5-4.5, P = 0.43). In an adjusted Cox model, the difference between miscarriage rates was also small and not significant (hazard ratio 1.36, 95% CI 0.63-2.93, P = 0.43). Premature birth was more frequent in exposed pregnancies (16.1% versus 8.5%; OR 2.1, 95% CI 1.1-3.8, P = 0.019). Nonetheless, median gestational age at birth (39 weeks, interquartile range [IQR] 37-40 versus 39 weeks, IQR 38-40, P = 0.27) and birth weight (3280 g, IQR 2835-3590 versus 3250 g, IQR 2880-3630, P = 0.95) did not differ between exposed and non-exposed pregnancies. CONCLUSIONS: This study did not detect a teratogenic effect of statins. Its statistical power remains insufficient to challenge current recommendations of treatment discontinuation during pregnancy.

[Prevalence of thyroid disease in healthcare workers occupationally exposed to ionizing radiation at the University Hospital of Pisa]. / Prevalenza di patologie tiroidee negli operatori sanitari radioesposti dell'Azienda Ospedaliero Universitaria Pisana.

The study analyzes the prevalence of thyroid disease in 1960 healthcare workers, classified as occupationally exposed to ionizing radiation, who have worked at the University Hospital of Pisa. They underwent a medical surveillance protocol from January 2005 until Mars 2012 at the Operative Unit of Occupational Medicine. A positive history of thyroid disease was found in 221 persons, but only 110 (the 5.61% of the population) developed the disease during or after the occupational exposure. Benign thyroid diseases, found in 93 workers, were in order of frequency: Hashimoto's thyroiditis, nodular disease, Basedow's disease, multinodular goiter, subacute thyroiditis and hypothyroidism. Malignant thyroid diseases were found in 17 workers (the 0.87% of the total population), 15 workers suffered from the papillary histotype and 2 from the medullary histotype.

[Preliminary study to evaluate the meaning of GGT fractions analysis in a population of workers previously exposed to asbestos]. / Studio preliminare volto all'inquadramento del significato preventive del dosaggio di frazioni di GGT in una popolazione di lavoratori ex-esposti ad Amianto.

The GGT enzyme, considered for years only as a marker of liver disease and alcohol abuse, has now revealed a risk of death for many causes. Through a molecular exclusion chromatography on FPLC system (Fast Protein Liquid Chromatography), it is possible to discriminate four fractions of GGT, defined according to the molecular weight: big-GGT, medium-GGT, small-GGT and free-GGT. The objective was to study the preventing meaning of GGT fractions for asbestos-related diseases. This study was conducted on 129 workers previously exposed to asbestos, 22 patients affected by Malignant Pleural Mesothelioma and 107 healthy workers. Our data demonstrated a statistical significant correlation between the fraction free-GGT with the presence of MPM, suggesting a possible role for this molecule as a biomarker for MPM diagnosis. However, being a preliminary study, further studies are warranted to confirm our results.

[Report of medical surveillance of workers exposed to asbestos at the Operative Unit of Occupational Medicine in Pisa]. / Attività di sorveglianza sanitaria dei lavoratori ex esposti ad amianto presso la Unità Operativa di Medicina Preventiva del Lavoro di Pisa.

We report our experience about the medical surveillance of 739 workers previously exposed to asbestos. They were observed during the period between January 2009 and May 2012. The diagnosis of 594 patients, that were observed for the first time, were analyzed in order to assess the presence of benign or malignant pulmonary diseases that is so found: 16.33% of benign pulmonary diseases related to asbestos, 17.84% benign pulmonary diseases not related to asbestos and 1% of malignant pulmonary diseases probably related to asbestos. The diagnosis of 221 patients, that were followed over time, were analyzed in order to assess the evolution in time: a new onset of pulmonary disease was found in the 2.26%, a worsening of the pulmonary disease was found in the 6.79%.

Nitroblue tetrazolium inhibits oxidation of glyceryl trinitrate to nitric oxide in bovine aortic smooth muscle cells.

The effects of nitroblue tetrazolium (NBT), a well-known scavenger of superoxide anions and an inhibitor of nicotinamide adenine dinucleotide (NADPH)-dependent oxidations, were assessed on the metabolism of glyceryl trinitrate (GTN) to nitric oxide (NO) by bovine aortic smooth muscle cells (SMC). The extent of this metabolism was determined by measuring NO formed, using the inhibition of thrombin-induced platelet aggregation and relaxation of rabbit aortic strips as bioassay systems. In addition, NO produced from GTN by SMC was measured as nitrite (NO2-), one of its breakdown products. The antiplatelet effect of GTN (44 microM) was potentiated by SMC (0.12-0.46 x 10(5) cells) treated with indomethacin (10 microM) and this was inhibited in a concentration-dependent manner when the cells were pretreated with NBT (100 microM). NBT (3-100 microM) also reduced the formation of NO2- from GTN (600 microM) by SMC (3 x 10(5) cells). Furthermore, relaxations of endothelium-denuded strips of the rabbit aorta by GTN (10(-9)-10(-6) M) were attenuated when the strips were pretreated with NBT (100 or 500 microM). The formation of NO from L-arginine (L-Arg) by SMC was not affected by NBT. The hypotensive responses to GTN (0.25-1 mg/kg, i.v.) in anaesthetized rats were inhibited by pretreatment with NBT (1.25 mg/kg, i.v.) but NBT did not alter the hypotensive responses induced by SIN-1. Thus, NBT inhibited the bioconversion of GTN to NO both in vitro and in vivo. NBT may be a useful pharmacological tool to investigate the enzymic pathway(s) involved in the conversion of GTN to NO by smooth muscle cells or other cells.

Generation of nitric oxide from nitrovasodilators modulates the release of histamine from mast cells.

The effect of organic and inorganic nitrovasodilators (sodium nitroprusside; 3-morpholinosydnonimine; glyceryl trinitrate; isosorbide dinitrate; sodium nitrite, was studied on the release of histamine evoked by compound 48/80 and calcium ionophore A 23187 in isolated purified rat serosal mast cells. All the compounds tested were capable of significantly reducing the release of histamine in a concentration-dependent fashion, at different levels of potency. This effect was reverted by oxyhaemoglobin. The inhibitory effect of glyceryl trinitrate on the release of histamine was potentiated in cells taken from animals pretreated with Escherichia coli lipopolysaccharide, and decreased by NG-nitro-L-arginine methyl ester. Glyceryl trinitrate and isosorbide dinitrate concentration-dependently increase the generation of nitric oxide by rat serosal mast cells. The inhibitory effect of glyceryl trinitrate and isosorbide dinitrate on the release of histamine from mast cells was potentiated by N-acetylcysteine, which significantly increases the generation of nitric oxide by mast cells. It is concluded that nitrovasodilators inhibit the release of mast cell histamine through the generation of nitric oxide. The effect may be relevant in considering the perivascular location of mast cells and the role played by these cells in cardiovascular pathophysiology.

Vascular and anti-platelet actions of 1,2- and 1,3-glyceryl dinitrate.

1. The aim of this study was to investigate whether two metabolites of glyceryl trinitrate (GTN), 1,2 and 1,3-glyceryl dinitrate (1,2-GDN and 1,3-GDN) could account for the pharmacological effects of GTN. To this end the formation of nitric oxide (NO) from 1,2- and 1,3-GDN in the presence of bovine aortic smooth muscle cells (SMC) or endothelial cells (EC) was studied. The effects of various thiols on NO formation from these dinitrates was also evaluated. 2. 1,2-GDN or 1,3-GDN (10(-10)-10(-5) M) caused a dose-dependent relaxation of rabbit aortic strips denuded of endothelium and precontracted with phenylephrine. The dinitrates were less than one tenth as potent as GTN. 3. Incubation of 1,2-GDN or 1,3-GDN (75-2400 microM) with SMC for 30 min led to a concentration-dependent increase in nitrite (NO2-) formation but this increase was less than that produced from GTN. Likewise incubation of 1,2-GDN or 1,3-GDN with N-acetylcysteine (NAC), glutathione (GSH) or thiosalicylic acid (TSA) (all at 1 mM) for 30 min at 37 degrees C produced a concentration-dependent increase in NO2- formation. 4. Platelet aggregation induced by thrombin (40 mu ml-1) was not modified by high concentrations of 1,2-GDN or 1,3-GDN (175-700 microM). However, aggregation was inhibited when platelets were exposed to 1,2-GDN or 1,3-GDN (700 microM) in the presence of SMC (0.24-1.92 x 10(5) cells) or EC (0.8-3.2 x 10(5) cells). These effects were abrogated by co-incubation with oxyhaemoglobin (OxyHb, 10 microM) indicating that they were due to NO release. The concentrations of the dinitrates required to inhibit platelet aggregation by 50% were about 15 times higher than for GTN in the presence of the same numbers of SMC or EC.5. When NAC or TSA (both at 0.5 mM) were co-incubated with platelets for 3 min in the presence of1,2-GDN or 1,3-GDN, a concentration-dependent inhibition of platelet aggregation was observed. These anti-platelet effects were abolished by co-incubation with OxyHb (10 microM). Glutathione had no potentiating effects.6. Thus the dinitrate metabolites of GTN are metabolized to NO by SMC or EC and are acted upon by thiols to form NO at concentrations about 10 times higher than those of GTN. In vivo, after oral or intravenous GTN, GDN levels are reached which are more than 10 times higher than those of GTN.These data support the notion that part of the effects of GTN are due to the generation of NO from 1,2-GDN and 1,3-GDN by the cells of the vascular wall.

Release of nitric oxide from glyceryl trinitrate by captopril but not enalaprilat: in vitro and in vivo studies.

1. The hypotensive effects of glyceryl trinitrate (GTN, 0.5 mg kg-1) but not of 3-morpholino-sydnonimine (SIN-1, 0.125 mg kg-1) in anaesthetized rats were attenuated following a seven day (using a q.i.d. dosing schedule) oral treatment with isosorbide-5-mononitrate (IS-5-MN; 5 mg kg-1) indicative of the induction of tolerance to GTN but not to SIN-1. The hypotensive effects of GTN did not decline when the sulphydryl (SH) containing angiotensin converting enzyme inhibitor (ACE-1), captopril (CPT, 5 mg kg-1) or the structurally unrelated SH-containing, N-acetylcysteine (NAC, 10 mg kg-1) but not the non-SH-containing ACE-I, enalaprilat (ENA, 5 mg kg-1) were given together with IS-5-MN for the seven days treatment. 2. The attenuated hypotensive effects of GTN (0.5 mg kg-1) in rats treated with IS-5-MN were also restored when CPT (1 mg kg-1) or NAC (2.5 mg kg-1) but not ENA (1 mg kg-1) was administered intraperitoneally (i.p.) 30 min before GTN. Furthermore, in control rats, CPT or NAC but not ENA given i.p. 30 min before GTN, potentiated its haemodynamic effects. These effects were blocked by methylene blue (10 mg kg-1). At the same doses, CPT or NAC did not affect the hypotensive effects of SIN-1. 3. The reduced ability of cultured tolerant smooth muscle cells (SMC, 24 x 103 cells) or endothelial cells(EC, 40 x 103 cells) to potentiate the anti-platelet effects of GTN (44 microM) was restored by CPT or NAC but not by ENA or glutathione (all at 0.5 mM). Potentiation of the anti-platelet effects of tolerant SMC or EC by CPT or NAC was abolished by co-incubation with oxyhaemoglobin (Oxy-Hb, 10 microM)indicative of nitric oxide (NO) formation.4. When GTN (150-2400 microM) was incubated with CPT, NAC or glutathione but not ENA (all at 0.1 mM) for 30 min in Krebs buffer at 37 degrees C a concentration-dependent increase in nitrite (NO2-)formation was observed. 5. The antiplatelet effects of GTN (5.5-352 microM) were potentiated by co-incubation with CPT or NAC but not with ENA or glutathione (all at 0.5 mM). The concentration of GTN required to inhibit platelet aggregation by 50% (IC50) was 110 +/- 2 microM for GTN alone, 14 +/- 2 microM for GTN in the presence of NAC and 30 +/- 2 microM for GTN in the presence of CPT. The potentiation of the effects of GTN by CPT or NAC was inhibited by co-incubation with Oxy-Hb (10 microM). By themselves, CPT or NAC did not inhibit platelet aggregation.6. The ability of CPT to restore (a) the haemodynamic effects of GTN in tolerant rats and (b) the reduced capacity of tolerant SMC or EC to potentiate the anti-platelet effects of GTN is not related to its ACE inhibitory activity.7. CPT also potentiated the hypotensive effects of GTN in non-tolerant rats, and in vitro CPT released NO from GTN in the absence of a GTN to NO converting cell, so that it is unlikely that reversal of tolerance by CPT is due to the replenishment of intracellular thiols. Rather it can be explained by the ability of CPT to release NO from GTN in the extracellular space. This extracellular formation of NO from GTN by CPT would then compensate for the impaired enzymic biotransformation of GTN to NO that develops during tolerance as was originally proposed for NAC.

Conversion of glyceryl trinitrate to nitric oxide in tolerant and non-tolerant smooth muscle and endothelial cells.

1. Exposure of smooth muscle cells (SMC) to glyceryl trinitrate (GTN, 75-600 microM) for 30 min led to a concentration-dependent increase in nitrite (NO2-), one of the breakdown products of nitric oxide (NO). This was not affected by 30 min pretreatment of the cells with 0.5 mM of sulphobromophthalein (SBP) an inhibitor of glutathione-S-transferase (GST), by metyrapone or SKF-525A inhibitors of cytochrome P450. These experiments were confirmed by organ bath studies using rabbit aortic strips denuded of endothelium and contracted with phenylephrine. Thus, a 30 min incubation of the strips with 0.5 mM SPB, metyrapone or SKF-525A did not affect the relaxations in response to GTN (10(-10)-10(-6) M). 2. Potentiation of the anti-platelet effect of GTN (44 microM) by endothelial cells (EC, 40 x 10(3) cells) was not affected by prior incubation of EC with SBP, metyrapone or SKF-525A (all at 0.5 mM). 3. Potentiation of the antiplatelet activity of GTN (11-352 microM) by small numbers of SMC (24 x 10(3) cells) or EC (40 x 10(3) cells) treated with indomethacin (10 microM) was attenuated when the SMC or EC were treated in culture with a high concentration of GTN (600 microM) for 18 h beforehand (referred to as 'tolerant' cells). In addition, tolerant SMC produced far less NO2- than non-tolerant SMC. 4. Exposure of non-tolerant SMC or EC (10(5) cells) to GTN (200 microM) for 3 min increased (3-4 fold) the levels of guanosine 3':5'-cyclic monophosphate (cyclic GMP). This increase was much less (< I fold) in the tolerant SMC or EC (105 cells). The basal levels of cyclic GMP were similar in normal or tolerant SMC or EC. Sodium nitroprusside (80 JAM) or atrial natriuretic factor (ANF, I0- M) increased the levels of cyclic GMP in normal or tolerant SMC or EC to the same extent.5 The anti-platelet effects of GTN (44 JM) were potentiated by the sulphydryl donor N-acetylcysteine(NAC, 0.5mM). Incubation of GTN (150-1200fJM) for 30min with NAC (0.1-1mM) led to aconcentration-dependent increase in N02- formation. The reduced ability of tolerant SMC or EC to potentiate the anti-platelet activity of GTN was restored by NAC (0.5 mM). These anti-aggregatory effects were abolished by concurrent co-incubation with oxyhaemoglobin (10 JM) indicating that they were due to NO release.6 Thus, in SMC or EC, metabolism of GTN to NO does not depend on glutathione-S-transferase or the cytochrome P450 system. Furthermore, when compared to normal cells, tolerant SMC or EC metabolize GTN to NO less effectively as assessed by the reduced capacity to potentiate the antiplatelet effects of GTN, to release NO2- and to increase the level of cyclic GMP. This decrease in NO formation shows that tolerance to GTN is mainly due to impaired biotransformation of GTN to NO. NAC, by directly forming NO from GTN, compensates for this failing mechanism.

Cultured astrocytoma cells generate a nitric oxide-like factor from endogenous L-arginine and glyceryl trinitrate: effect of E. coli lipopolysaccharide.

1. The inhibitory activity of astrocytoma cells (0.25-3 x 10(5)) treated with indomethacin (10 microM) on platelet aggregation was enhanced by incubating the cells with E. coli lipopolysaccharide (LPS, 0.5 micrograms ml-1) for 18 h. This effect was attenuated when cycloheximide (10 micrograms ml-1) was incubated together with LPS. The inhibition of platelet aggregation by cells treated with LPS was potentiated by superoxide dismutase (60 u ml-1) and ablated by oxyhaemoglobin (oxyHb, 10 microM) or NG-monomethyl-L-arginine (L-NMMA, 30-300 microM). The effects of L-NMMA were reversed by co-incubation with L-arginine (L-Arg, 100 microM) but not D-arginine (D-Arg, 100 microM). LPS also increased the levels of nitrite in the culture media and this increase was ablated by co-incubation with L-NMMA (300 microM) or cycloheximide (10 micrograms ml-1). 2. Astrocytoma cells (0.5 x 10(5)) treated with indomethacin (10 microM) enhanced the platelet inhibitory activity of glyceryl trinitrate (GTN, 11-352 microM) but not that of sodium nitroprusside (4 microM). Furthermore, when incubated with GTN (200 microM) a 4 fold increase in the levels of guanosine 3':5'-cyclic monophosphate (cyclic GMP) was observed. These effects were abrogated by co-incubation with oxyHb (10 microM) but not with L-NMMA (300 microM). Treatment of the cells with LPS (0.5 micrograms ml-1) for 18 h did not enhance their capacity to form NO from GTN. 3. Thus, in cultured astrocytoma cells, LPS enhances the formation of nitric oxide from endogenous L-arginine.In addition, these cells can metabolize GTN to nitric oxide but this process is not enhanced by LPS stimulation.

The metabolism of glyceryl trinitrate to nitric oxide in the macrophage cell line J774 and its induction by Escherichia coli lipopolysaccharide.

The metabolism of glyceryl trinitrate (GTN) to nitric oxide (NO) was studied in the mouse macrophage cell line J774 and in the human monocytic cell line U937 in the absence or presence of Escherichia coli lipopolysaccharide (LPS). Two bioassay systems were used: inhibition of platelet aggregation and measurement of cGMP after stimulation by NO of guanylate cyclase in J774 cells. In addition, NO produced from GTN by cells or by cellular fractions was measured as nitrite (NO2-) one of its breakdown products. J774 cells (1.25 x 10(5) cells) treated with indomethacin (10 microM) enhanced the platelet inhibitory activity of GTN (22-352 microM) but not that of sodium nitroprusside (4 microM). This effect was abrogated by co-incubation with oxyhaemoglobin (oxyHb, 10 microM) indicating release of NO from GTN. U937 cells (up to 60 x 10(5)) did not metabolize GTN to NO. LPS (0.5 micrograms/mL for 18 hr) enhanced at least 2-fold the capacity of J774 cells but not that of U937 cells to form NO from GTN and this enhancement was attenuated when cycloheximide (10 micrograms/mL) was incubated together with LPS. In the absence of LPS stimulation, cycloheximide had no effect. Furthermore, when incubated with GTN (200 microM), J774 cells treated with LPS released more NO from GTN as indicated by a 3-fold greater increase in their level of cGMP which was prevented by oxyHb (10 microM). Incubation of J774 cells with GTN (75-600 microM) for 30 min led to a concentration-dependent increase in NO2- which was substantially reduced when the cells were boiled. The microsomal fraction was more potent than the cytosol in producing NO2- from GTN (1.2-2.4 mM). Release of NO2- from GTN by J774 cells was not affected by treating the cells with the NO synthase inhibitor, NG-monomethyl-L-arginine (MeArg, 300 microM). In J774 cells made tolerant to GTN, potentiation of the anti-platelet effects of GTN (11-352 microM) and release of NO2- from GTN was reduced. Thus, J774 cells but not U937 cells convert GTN to NO. This enzymic pathway (present mainly in the microsomal fraction of the J774 cells) is induced by LPS and is not regulated by endogenous NO released from L-Arg by the enzyme NO synthase. Furthermore, when compared to normal cells, tolerant J774 cells metabolize GTN to NO less effectively as assessed by a reduced capacity to potentiate the anti-platelet effect of GTN and to release NO2-.(ABSTRACT TRUNCATED AT 400 WORDS)

Mast cell degranulating (MCD) peptide analogs with reduced ring structure.

Mast cell degranulating (MCD) peptide, a component of bee venom, is a 22 amino acid peptide with two disulfide bridges. In this first structure-activity study of MCD peptide, three analogs were synthesized and tested: two analogs shortened by omitting sequences 6-10 and 8-13, respectively, and one analog lacking the disulfide bridge between cysteine residues 5 and 19. These analogs were synthesized by solid-phase methods and were compared to MCD peptide in two assays for inflammation: histamine release from mast cells and superoxide anion release from neutrophils. All three analogs produced histamine release, although with only about one fifth of the activity of MCD peptide. Superoxide anion-releasing activity, however, did not parallel histamine release. MCD peptide did not release superoxide anion, while the 6-10 and 8-13 deletion analogs were strong and weak stimulants, respectively, of this anion. CD spectra showed that the secondary structures of the three analogs were very similar to that of MCD peptide, so that a change in secondary structure cannot completely explain the changes in releasing activities. Charge differences between the two deletion analogs and MCD peptide may explain some of the differences in activity. This is the first demonstration that the various activities of MCD peptide can be separated, and provides a lead through which the purported antiinflammatory activity of MCD peptide may possibly be explored in the future.

[Contribution of glutathione to detoxification in alcoholism. Biochemical-clinical studies]. / L'apporto di glutatione nella detossificazione dell'alcolismo. Indagini biochimico-cliniche.

The effects of reduced glutathione (GSH) administration (1.2 g/day and 2.4 g/day intravenously) on erythrocyte glutathione levels, serum gamma-glutamyl transpeptidase activity (GGTP) and urinary glucaric acid elimination were studied in a population of 24 chronic alcoholics voluntarily admitted to a 30 day detoxification protocol in comparison to a 12 patient control group treated only with chlordiazepoxide (initial dose 75-100 mg/day). Glutathione treatment increases dose-dependently and in a significant way erythrocyte glutathione levels and hastens the recovery of serum GGTP and urinary glucaric acid elimination. The relationship between glutathione, GGTP and glucaric acid is discussed, suggesting the possible role of GSH against the oxidative damage of alcohol.

Metabolism of glyceryl trinitrate to nitric oxide by endothelial cells and smooth muscle cells and its induction by Escherichia coli lipopolysaccharide.

Here, we demonstrate that the metabolism of glyceryl trinitrate (GTN) to nitric oxide (NO) occurs not only in bovine aortic smooth muscle cells (SMCs) but also in endothelial cells (ECs) and that this biotransformation is enhanced by pretreatment with Escherichia coli lipopolysaccharide (LPS). Two bioassay systems were used: inhibition of platelet aggregation and measurement of cGMP after stimulation by NO of guanylate cyclase in SMCs or ECs. In addition, NO produced from GTN by cells was measured as nitrite (NO2-), one of its breakdown products. Indomethacin (10 microM)-treated SMCs or ECs enhanced the platelet inhibitory activity of GTN. This effect was abrogated by coincubation with oxyhemoglobin (oxyHb; 10 microM), indicating release of NO from GTN. LPS (0.5 microgram/ml; 18 h) enhanced at least 2- to 3-fold the capacity of SMCs or ECs to form NO from GTN, and this enhancement was attenuated when cycloheximide (10 micrograms/ml) was incubated together with LPS. Furthermore, when incubated with GTN (200 microM) SMCs or ECs treated with LPS (0.5 microgram/ml; 18 h) released more NO from GTN than nontreated cells as indicated by a much higher (8- to 9-fold) increase in the levels of cGMP. Exposure of SMCs to GTN (600 microM) for 30 min led to an increase in the levels of NO2- dependent on cell numbers, which was enhanced when SMCs were treated with LPS. Incubation of nontreated or LPS-treated cells with NG-monomethyl-L-arginine (300 microM; 60 min) did not influence the metabolism of GTN to NO. SMCs failed to enhance the antiplatelet activity of sodium nitroprusside. Anesthetized rats treated with an intraperitoneal injection of LPS (20 mg/kg) 18 h beforehand showed enhanced hypotensive responses to GTN (0.25-1 mg/kg). These effects were blocked by methylene blue (10 mg/kg) but not by indomethacin (3 mg/kg). LPS did not alter the hypotensive responses induced by phentolamine, verapamil, or SIN-1. Thus, both in vitro and in vivo, LPS induces the enzyme(s) metabolizing GTN to NO.

HBV and HCV infection in i.v. drug addicts; coinfection with HIV.

A group of 122 drug addict patients were studied to evaluate the incidence of HIV, HBV, HCV infections and of laboratory findings of hepatic damage. Our data show that hepatic damage is more frequent in patients affected by HBV-HCV coinfection than those with HBV or HCV infection alone and that HIV positivity supports HBV-HCV coinfection.

Correlation between Nitric Oxide Synthesis and Histamine Release in Mast Cells from Spontaneously Hypertensive Rats: Influence of Aging.

Isolated perfused hearts and serosal mast cells (MC) of 2- 6- and 18-month-old spontaneously hypertensive rats (SH) were compared to hearts and MC from Wistar-Kyoto (WKY) rats of the same age for their ability to release nitric oxide (NO). The relationship between histamine release and NO production was also investigated. In hearts and MC of 2-, 6- and 18-month-old SH rats, the production of NO is significantly lower than in hearts or MC of WKY rats of the same age. Concomitantly, the spontaneous release of histamine in cardiac perfusates and MC reactivity to various exocytotic stimuli (compound 48/80, calcium ionophore A 23187) is modified by aging and hypertension.

Impairment of the L-arginine-nitric oxide pathway in mast cells from spontaneously hypertensive rats.

Serosal mast cells (MC) from 6 month old spontaneously hypertensive rats (SHR) were compared to MC from 6 month old Wistar Kyoto rats (WKYR) for their ability to release nitric oxide (NO). The relationship between histamine release and NO-like activity from these cells was also investigated. MC from SHR released less NO-like factor than MC from WKYR as assessed by the use of platelet aggregation and soluble guanylate cyclase activation as bioassays for NO. Sodium nitroprusside elevated the concentrations of cGMP to a similar extent in MC from SHR or WKYR. No changes in the levels of cAMP were observed. The release of histamine from MC induced by compound 48/80 or the calcium ionophore A23187 was greater in MC from SHR than in MC from WKYR. Thus, MC from SHR show a decreased production of NO-like activity which is reflected by a decreased ability to inhibit platelet aggregation. The decreased production of cGMP in the MC leads to an increased stimulated release of histamine.