Tyrosine kinases and calcium dependent activation of endothelial cell phospholipase D by diperoxovanadate

Reactive oxygen species (ROS) mediated modulation of signal transduction pathways represent an important mechanism of cell injury and barrier dysfunction leading to the development of vascular disorders. Towards understanding the role of ROS in vascular dysfunction, we investigated the effect of diperoxovanadate (DPV), derived from mixing hydrogen peroxide and vanadate, on the activation of phospholipase D (PLD) in bovine pulmonary artery endothelial cells (BPAECs). Addition of DPV to BPAECs in the presence of .05% butanol resulted in an accumulation of [32P] phosphatidylbutanol (PBt) in a dose- and time-dependent manner. DPV also caused an increase in tyrosine phosphorylation of several protein bands (Mr 20-200 kD), as determined by Western blot analysis with antiphosphotyrosine antibodies. The DPV-induced [32P] PBt-accumulation was inhibited by putative tyrosine kinase inhibitors such as genistein, herbimycin, tyrphostin and by chelation of Ca2+ with either EGTA or BAPTA, however, pretreatment of BPAECs with the inhibitor PKC bisindolylmaleimide showed minimal inhibition. Also down-regulation of PKC alpha and epsilon, the major isotypes of PKC in BPAECs, by TPA (100 nM, 18 h) did not attenuate the DPV-induced PLD activation. The effects of putative tyrosine kinase and PKC inhibitors were specific as determined by comparing [32P] PBt formation between DPV and TPA. In addition to tyrosine kinase inhibitors, antioxidants such as N-acetylcysteine and pyrrolidine dithiocarbamate also attenuated DPV-induced protein tyrosine phosphorylation and PLD stimulation. These results suggest that oxidation, prevented by reduction with thiol compounds, is involved in DPV-dependent protein tyrosine phosphorylation and PLD activation.

Nitric oxide attenuates H(2)O(2)-induced endothelial barrier dysfunction: mechanisms of protection

Nitric oxide (.NO) attenuates hydrogen peroxide (H(2)O(2))-mediated injury in porcine pulmonary artery endothelial cells (PAECs) and modulates intracellular levels of cGMP and cAMP. We hypothesized that.NO attenuates H(2)O(2)-induced PAEC monolayer barrier dysfunction through cyclic nucleotide-dependent signaling mechanisms. To examine this hypothesis, cultured PAEC monolayers were treated with H(2)O(2), and barrier function was measured as transmonolayer albumin clearance. H(2)O(2) caused significant PAEC barrier dysfunction that was attenuated by intracellular as well as extracellular.NO generation.NO increased PAEC cGMP and cAMP levels, but treatment with inhibitors of soluble guanylate cyclase or protein kinase G did not abrogate.NO-mediated barrier protection. In contrast, H(2)O(2) decreased protein kinase A activity, and inhibiting protein kinase A abrogated the protective effect of.NO. H(2)O(2)-induced barrier dysfunction was not associated with decreased levels of cGMP or cAMP. 3-Isobutyl-1-methylxanthine and the cGMP analog 8-bromo-cGMP had little effect on H(2)O(2)-mediated endothelial barrier dysfunction, whereas 8-bromo-cAMP plus 3-isobutyl-1-methylxanthine was protective. These results indicate that.NO modulates vascular endothelial barrier function through cAMP-dependent signaling mechanisms.

Ascher's syndrome: a rare cause of lip swelling

Ascher's syndrome is a rare, benign entity with just over 100 reported cases. The condition is characterised by a 'double' upper lip, blepharochalasis and non-toxic thyroid enlargement. It presents before the age of 20 years in the majority of cases and shows no racial or gender differences. While the exact cause is unknown, hormonal dysfunction and autosomal dominant inheritance have been suggested as possible aetiological factors. We present two cases of Ascher's syndrome referred for investigation of lip swelling.

Should left- and right-sided unilateral cleft lip and palate patients be grouped together when reporting the outcomes?

OBJECTIVES

Investigate associations between cleft laterality in patients with non-syndromic unilateral cleft lip and palate (UCLP) and oral-health, dental-arch, speech, audiological, psychological and nasolabial-aesthetic outcomes.

METHODS

Secondary data analysis of the outcomes of 5-year-old children with non-syndromic complete UCLP identified from three studies: Cleft Collective (n = 155), Cleft Care UK (CCUK) (n = 266) and Clinical Standards Advisory Group (CSAG) study (n = 238). Outcome measures included occlusal assessment using the 5-year-old's index score, speech intelligibility rating using the CAPS-A Audit tool, audiological assessment using pure tone audiometry, nasolabial aesthetic assessment using the Asher-McDade tool, oral-health assessment using decayed, missing, filled teeth scores and parent-reported outcomes. Logistic regression with adjustment for age, sex and index-of-multiple-deprivation scores were performed.

RESULTS

No differences were found in patient-reported outcomes between the left and right clefts in the Cleft Collective study. From the CCUK study, right clefts had poorer speech (n = 236; 95% CI 1.09, 3.42; and P = .03) and hearing outcomes (n = 211; 95% CI 1.03, 3.43; P = .04). In the CSAG study, patients with left clefts were more likely to be teased (n = 213; 95% CI 0.26, 0.85; and P = .01).

CONCLUSION

Weak associations between cleft laterality, speech, hearing and psychological outcomes were found, however the findings were inconsistent across the studies. This study contributes to evidence of associations between laterality and outcomes in children born with UCLP.