Hydrogen sulphide: biopharmacological roles in the cardiovascular system and pharmaceutical perspectives

Hydrogen sulphide (H(2)S) is now viewed as an important endogenous gasotransmitter, which exhibits many beneficial effects on the cardiovascular system. H(2)S is biosynthesized in mammalian tissues by both non-enzymatic processes and several enzymatic pathways ensured by cystathionine-β-synthase and cystathionine-γ-lyase. H(2)S is endowed with the antioxidant properties of inorganic and organic sulphites, being a scavenger of reactive oxygen species. Furthermore, H(2)S triggers other important effects and the activation of ATP-sensitive potassium channels (KATP) accounts for its vasorelaxing and cardioprotective effects. H(2)S also inhibits smooth muscle proliferation and platelet aggregation. Conversely, the impairment of H(2)S contributes to the pathogenesis of hypertension and is involved in cardiovascular complications associated with diabetes mellitus. There is also evidence of a link between H(2)S and endothelial nitric oxide (NO). Recent observations indicate a possible pathogenic link between deficiencies of H(2)S activity and the progress of endothelial dysfunction. These biological aspects of endogenous H(2)S led to consider this mediator as "the new NO" and to evaluate new attractive opportunities to develop innovative classes of drugs. In this review, the main roles played by H(2)S in the cardiovascular system and the first examples of H(2)S-donor drugs are discussed. Some hybrid drugs are also addressed in this review. In such compounds opportune H(2)S-releasing moieties are conjugated to well-known drugs to improve their pharmacodynamic profile or to reduce the potential for adverse effects.

Fully covered self-expandable metallic stents in benign biliary strictures: a multicenter study on efficacy and safety

BACKGROUND AND STUDY AIM

Benign biliary diseases include benign biliary stricture (BBS), lithiasis, and leaks. BBSs are usually treated with plastic stent placement; use of uncovered or partially covered metallic stents has been associated with failure related to mucosal hyperplasia. Some recently published series suggest the efficacy of fully covered self-expandable metal stents (FCSEMSs) in BBS treatment. We aimed to assess the efficacy and safety of FCSEMS in a large series of patients with BBS and a long follow-up. 

PATIENTS AND METHODS

Prospective multicenter clinical study at three tertiary referral centers: ISMETT/UPMC Italy, Palermo, San Paolo Hospital, Milan, and the ARNAS Civico Hospital, Palermo, Italy. All consecutive patients with BBS were treated with placement of FCSEMS rather than plastic stents, as first approach (11 patients, 17.7 %), or as a second approach after failure of other treatments (51 patients, 82.2 %).

RESULTS

From January 2008 to March 2011, 62 patients (40 male) were included. Mean period of FCSEMS indwelling was 96.7 days (standard deviation [SD] 6.5 days). In 15 patients (24.2 %) the SEMS migrated. Resolution of BBS occurred in 56 patients (90.3 %), while in 6 (9.6 %) the treatment failed. Mean (SD) follow-up after SEMS removal was 15.9 (10) months. FCSEMS placement as first- or second-line approach showed no difference in failure. Recurrence was observed in 4 /56 patients (7.1 %); all were transplant recipients: P = 0.01; odds ratio (OR) 1.2, confidence interval (CI) 1.1 - 1.3.

CONCLUSIONS

Despite the noteworthy migration rate, FCSEMSs should be considered effective for refractory benign biliary strictures. Further studies are needed to assess their role as a first approach in the management of BBS.

Nematocytes' activation in Pelagia noctiluca (Cnidaria, Scyphozoa) oral arms

Nematocytes' discharge is triggered to perform both defense and predation strategies in cnidarians and occurs under chemico-physical stimulation. In this study, different compounds such as amino acids and proteins (mucin, albumin, poly-L: -lysine, trypsin), sugars and N-acetylate sugars (N-acetyl neuraminic acid, N-acetyl galactosamine, sucrose, glucose, agarose and trehalose), nucleotides (ATP and cAMP), were tested as chemosensitizers of nematocyte discharge in the oral arms of the scyphozoan Pelagia noctiluca, particularly abundant in the Strait of Messina (Italy). Excised oral arms were submitted to a combined chemico-physical stimulation by treatment with different compounds followed by mechanical stimulation by a non-vibrating test probe. Discharge induced by a chemico-physical stimulation was more significant than that obtained after mechanical stimulation alone. A chemosensitizing mechanism, with a dose-dependent effect, was observed after treatment with sugars, amino compounds such as glutathione, nucleotides and mucin, according to that already seen in sea anemones. Such findings suggest that, though Anthozoa and Scyphozoa exhibit different divergence times during the evolutionary process, the discharge activation exhibits common features, probably derived from their last common ancestor.

Rapid maxillary expansion in children with Obstructive Sleep Apnoea Syndrome (OSAS)

AIM

to evaluate the effects of rapid maxillary expansion (RME) in a group of OSAS preschool children.

MATERIALS AND METHODS

Lateral cephalograms of 15 OSAS children (8 boys and 7 girls, age mean ± SD: 5.94 ± 1.64 years) were analysed at the start of treatment with RME (T0). All subjects were revaluated after a mean period of 1.57 ± 0.58 years (T1). At this time the sample was divided into 2 groups according to the change in the respiratory disturbance index (RDI): an improved group (I: 8 subjects) and a stationary/worsened group (SW: 7 subjects). Differences between I and SW children with respect to values of cephalometric variables at T0 and to variations between T0 and T1 were evaluated using Mann-Whitney U test. Differences between T0 and T1 values in the overall group of children and separately in I and SW groups were assessed using Wilcoxon test.

RESULTS

At the start of treatment, the I group was characterised by more retrognathic jaws with lower values of SNA (p=0.055) and SNB (p=0.020) and higher age values (p=0.093) when compared to SW group. After treatment, the I group showed an increase in SNA and SNB angle significantly higher than SW group (p=0.004 and p=0.003, respectively). On the contrary, I and SW groups did not differ as for variation in the skeletal divergency and in the total facial height.

CONCLUSION

OSAS preschool children with retrognathic jaws could benefit from RME treatment.

Long-term outcomes in survivors of acute respiratory distress syndrome ventilated in supine or prone position

PURPOSE

The aim of this study is to examine long-term pulmonary function and quality of life in survivors of acute respiratory distress syndrome (ARDS) previously enrolled in a randomized multicenter trial testing prone compared with supine positioning (PSII study) at five Italian centers.

DESIGN

Observational prospective study.

SUBJECTS AND MEASUREMENTS

Pulmonary function [spirometric test, gas exchange, carbon monoxide diffusion capacity (DLCO)], high-resolution computed tomography (CT) scan, and health-related quality of life [Short Form-36 (SF-36) and St. George's Respiratory Questionnaire] were evaluated at 12 months.

RESULTS

Twenty-six patients (13 in each group, mean age 54.1 ± 2.8 years, body mass index 24.5 ± 1.4 kg/m(2), PaO(2)/FiO(2) 117 ± 49 mmHg) were evaluated. There were no significant differences in demographic data, illness severity, or outcome between the prone and supine groups. The overall survival rate was 40%. Pulmonary function was in the normal range without any differences between the two groups. Quantitative lung CT scan analysis showed similar amounts for not aerated (8.1 ± 3.2% versus 7.3 ± 3.4%), poorly aerated (15.3 ± 3.6% versus 17.1 ± 4.9%), and well-aerated (64.0% ± 8.4 versus 70.2 ± 8.4%) lung regions, while overaerated lung region was slightly higher in the prone compared with the supine group (12.5 ± 6.5% versus 5.3 ± 5.5%). Health-related quality of life was similar to in healthy population. However, these patients showed reduction in daily activity specifically due to pulmonary disease as measured by the St. George's Respiratory Questionnaire.

CONCLUSIONS

No differences in pulmonary function or quality of life were observed in this small group of ARDS survivor patients treated in prone versus supine position.

Phenolic composition and biological activities of Juniperus drupacea Labill. berries from Turkey

The present study was designed to define the phenolic profile and the biological potential of berries methanol extract of Juniperus drupacea Labill. from Turkey. The total phenolic content (Folin-Ciocalteau assay) was 48.06±0.99mgGAE/g extract. The HPLC-DAD-ESI-MS analysis allowed the determination of the complete phenolic profile of J. drupacea berries. Phenolic acids represented more than 60% of the total phenolics, and tyrosol was the major one (1324±0.64μg/g extract); within the flavonoids amentoflavone was detected as the main constituent (927±0.35μg/g extract). The extract exhibited good antioxidant properties, as determined by different in vitro models: DPPH test (IC(50) 0.38±0.02mg/mL), reducing power (12.63±0.14ASE/mL), Fe(2+) chelating ability (IC(50) 2.26±0.06mg/mL), and TBA test (IC(50) 2.47±1.13μg/mL). Cytotoxicity against Artemia salina was highlighted (LC(50) 489.47±27.8μg/mL), and a significant decrease (p⩽0.05; p⩽0.01) in HepG2 cells viability was observed at the higher concentrations (5-10μg/mL). The extract displayed good antibacterial activity towards Gram-positive bacteria and in particular Staphylococcus aureus was the most susceptible strain (MIC 78.12μg/mL).