A fish bradykinin (Arg0; Trp5; Leu8-bradykinin) from the defensive skin secretion of the European edible frog; Pelophylax kl. esculentus: structural characterization; molecular cloning of skin kininogen cDNA and pharmacological effects on mammalian smooth muscle

Extensive studies on bradykinin-related peptides (BRPs) generated from plasma kininogens in representative species of various vertebrate taxa, have confirmed that many amphibian skin BRPs reflect those present in putative vertebrate predators. For example, the (Val1, Thr6)-bradykinin, present in the defensive skin secretions of many ranids and phyllomedusines, can be generated from plasma kininogens in colubrid snakes - common predators of these frogs. Here, we report the presence of (Arg0, Trp5, Leu8)-bradykinin in the skin secretion of the European edible frog, Pelophylax kl. esculentus, and have found it to be encoded in single copy by a kininogen with an open-reading frame of 68 amino acid residues. This peptide is the archetypal bony fish bradykinin that has been generated from plasma kininogens of the bowfin (Amia calva), the long-nosed gar (Lepisosteus oseus) and the rainbow trout (Onchorhynchus mykiss). More recently, this peptide has been shown to be encoded within cloned kininogens of the Atlantic cod (Gadus morhua) spotted wolf-fish (Anarichas minor), zebrafish (Danio rerio), pufferfish (Tetraodon nigroviridis) and Northern pike (Esox lucius). The latter species is regarded as a major predator of P. kl. esculentus. Synthetic (Arg0, Trp5, Leu8)-bradykinin was previously reported as having multiphasic effects on arterial blood pressure in conscious trout and here we have demonstrated that it can antagonize the relaxation in rat arterial smooth muscle induced by canonical mammalian bradykinin. The discovery of (Arg0, Trp5, Leu8)-bradykinin in the defensive skin secretion of this amphibian completes the spectrum of vertebrate taxon-specific BRPs identified from this source.

FMRFamide-like peptides (FLPs) enhance voltage-gated calcium currents to elicit muscle contraction in the human parasite Schistosoma mansoni.

Schistosomes are amongst the most important and neglected pathogens in the world, and schistosomiasis control relies almost exclusively on a single drug. The neuromuscular system of schistosomes is fertile ground for therapeutic intervention, yet the details of physiological events involved in neuromuscular function remain largely unknown. Short amidated neuropeptides, FMRFamide-like peptides (FLPs), are distributed abundantly throughout the nervous system of every flatworm examined and they produce potent myoexcitation. Our goal here was to determine the mechanism by which FLPs elicit contractions of schistosome muscle fibers. Contraction studies showed that the FLP Tyr-Ile-Arg-Phe-amide (YIRFamide) contracts the muscle fibers through a mechanism that requires Ca2+ influx through sarcolemmal voltage operated Ca2+ channels (VOCCs), as the contractions are inhibited by classical VOCC blockers nicardipine, verapamil and methoxyverapamil. Whole-cell patch-clamp experiments revealed that inward currents through VOCCs are significantly and reversibly enhanced by the application of 1 µM YIRFamide; the sustained inward currents were increased to 190% of controls and the peak currents were increased to 180%. In order to examine the biochemical link between the FLP receptor and the VOCCs, PKC inhibitors calphostin C, RO 31–8220 and chelerythrine were tested and all produced concentration dependent block of the contractions elicited by 1 µM YIRFamide. Taken together, the data show that FLPs elicit contractions by enhancing Ca2+ influx through VOCC currents using a PKC-dependent pathway.

Elevated AGE-modified ApoB in sera of euglycemic, normolipidemic patients with atherosclerosis: relationship to tissue AGEs.:relationship to tissue AGEs

BACKGROUND: Advanced glycation endproducts (AGEs) are implicated in the pathogenesis of atherosclerotic vascular disease of diabetic and nondiabetic etiology. Recent research suggests that advanced glycation of ApoB contributes to the development of hyperlipidemia. AGE-specific receptors, expressed on vascular endothelium and mononuclear cells, may be involved in both the clearance of, and the inflammatory responses to AGEs. The aim of this study was to examine whether there is a relationship between serum AGE-ApoB and AGEs in arterial tissue of older normolipidemic nondiabetic patients with occlusive atherosclerotic disease, compared with age-matched and younger asymptomatic persons.

MATERIALS AND METHODS: Serum AGE-ApoB was measured by ELISA in 21 cardiac bypass patients. Furthermore, an AGE-specific monoclonal antibody, and polyclonal antibodies against anti-AGE-receptor (anti-AGE-R) 1 and 2 were used to explore the localization and distribution of AGEs and AGE-R immunoreactivity (IR) in arterial segments excised from these patients.

RESULTS: Serum AGE-ApoB levels were significantly elevated in the asymptomatic, older population, compared with those in young healthy persons (259 +/- 24 versus 180 +/- 21 AGE U/mg of ApoB, p < 0.01). Higher AGE-ApoB levels were observed in those patients with atherosclerosis (329 +/- 23 versus 259 +/- 24 AGE U/mg ApoB, p < 0.05). Comparisons of tissue AGE-collagen with serum AGE-ApoB levels showed a significant correlation (r = 0.707, p < 0.01). In early lesions, AGE-IR occurred mostly extracellularly. In fatty streaks and dense, cellular atheromatous lesions, AGE-IR was visible within lipid-containing smooth muscle cells and macrophages, while in late-stage, acellular plaques, AGE-IR occurred mostly extracellularly. AGE-R1 and -R2 were observed on vascular endothelial and smooth-muscle cells and on infiltrating mononuclear cells in the early-stage lesions, whereas in dense, late-stage plaques, they colocalized mostly with lipid-laden macrophages. On tissue sections, scoring of AGE-immunofluorescence correlated with tissue AGE and plasma AGE-ApoB.

CONCLUSIONS: (1) The correlation between arterial tissue AGEs and circulating AGE-ApoB suggests a causal link between AGE modification of lipoproteins and atherosclerosis. AGE-specific receptors may contribute to this process. (2) Serum AGE-ApoB may serve to predict atherosclerosis in asymptomatic patients.

Supplemental oxygen and hyperbaric treatment at high altitude: Cardiac and respiratory response

Introduction: The most effective treatment for high altitude sickness is prompt descent. However, rapid descent is sometimes impossible and alternative solutions are desirable. Supplemental oxygen at ambient pressure and hyperbaric oxygen in a hyperbaric tent have both been demonstrated to improve symptoms and increase arterial oxygenation (SaO(2)) in those with high altitude sickness; however, their use in combination has not previously been described in a controlled study. Methods and Results: In this feasibility study, the SaO(2) of six healthy, well-acclimatized participants rose from 76.5 to 97.5% at 4900 m and 72.5 to 96.0% at 5700 m following the administration of oxygen via a nasal demand circuit (33 ml of oxygen per pulse) inside a hyperbaric tent (107 mmHg above ambient barometric pressure) (p

Promoting Health Behaviour Change in the Cardiac Patient

The importance of giving patients advice in relation to positive health behaviour change geared towards maximizing physical health must not be overlooked and is an important role of the cardiac nurse in contemporary health care. However, over-reliance on offering advice can often be counter-productive and less likely to achieve effective change. Patients are more likely to make positive health behaviour changes when they self-generate their own solutions to the health issues and problems that they face. In this article, the authors encourage cardiac nurses to embrace a less directive and more facilitative approach to patient health behaviour change in light of the mounting evidence that exists to the effectiveness of motivational interviewing techniques.

Hypoglycaemia, liver necrosis and perinatal death in mice lacking all isoforms of phosphoinositide 3-kinase p85 alpha

Phosphoinositide 3-kinases produce 3'-phosphorylated phosphoinositides that act as second messengers to recruit other signalling proteins to the membrane(1). Pi3ks are activated by many extracellular stimuli and have been implicated in a variety of cellular responses(1). The Pi3k gene family is complex and the physiological roles of different classes and isoforms are not clear. The gene Pik3r1 encodes three proteins (p85 alpha, p55 alpha and p50 alpha) that serve as regulatory subunits of class I-A Pi3ks (ref. 2). Mice lacking only the p85a isoform are viable but display hypoglycaemia and increased insulin sensitivity correlating with upregulation of the p55 alpha and p50 alpha variants(3). Here we report that loss of all protein products of Pik3r1 results in perinatal lethality. We observed, among other abnormalities, extensive hepatocyte necrosis and chylous ascites, We also noted enlarged skeletal muscle fibres, brown fat necrosis and calcification of cardiac tissue. In liver and muscle, loss of the major regulatory isoform caused a great decrease in expression and activity of class I-A Pi3k catalytic subunits: nevertheless, homozygous mice still displayed hypoglycaemia, lower insulin levels and increased glucose tolerance. Our findings reveal that p55 alpha and/or p50 alpha are required for survival, but not for development of hypoglycaemia, in mice lacking p85 alpha.