Cardioprotection of cariporide evaluated by plasma myoglobin and troponin I in myocardial infarction in pigs.

The cardioprotective effects of cariporide were investigated against myoglobin and troponin I elevation in a model of myocardial infarction in pig, and the possible relationship between these markers and myocardial infarct size. The left circumflex coronary artery was ligated for 60-min and then reperfused for 48-h. Plasma levels of myoglobin and troponin I were quantified during reperfusion. Vehicle or cariporide (2.5 mg/kg) were administered i.v. before ischaemia and infused throughout ischaemia and for the beginning of reperfusion. In vehicle-treated pigs, the infarct size represented 26% +/- 3% of the area at risk. Cariporide significantly decreased the infarct size by 66% +/- 9%, and significantly reduced plasma levels of myoglobin and troponin I. A strongly correlated linear relationship between myocardial necrosis and plasma levels of myoglobin (R = 0.966, P < 0.0001) or troponin I (R = 0.855, P < 0.0001) was clearly identified. In conclusion, in our porcine model of myocardial infarction, even with small infarcts (in the presence of cariporide), plasma levels of myoglobin and troponin I are predictive of the presence of necrosis and its extent.

Treatment of Aphthous Stomatitis with topical Alchemilla vulgaris in glycerine.

BACKGROUND AND OBJECTIVE: Recurrent aphthous ulceration is the most common oral mucosal disease known. It presents as three types: minor (most prevalent), major and herpetiform. However, there are no well established effective and reliable treatments of this condition. Alchemilla vulgaris (Lady's Mantle) has traditionally been used in oral hygiene and was recently shown to accelerate wound healing when used in combination with glycerine. The objective of this study was to determine whether this combination is effective in the treatment of the most prevalent form of aphthous ulcers. METHODS: An open-label study was conducted in 48 otherwise healthy male and female patients aged 4-44 years to determine the putative healing properties and tolerability of a standard 3% extract of A. vulgaris in glycerine (Aphtarine) on common minor oral ulcers. Patients with major or herpetiform ulcers were excluded from the study. RESULTS: Topical application three times daily of Aphtarine gel to minor mouth ulcers relieved discomfort and produced complete healing in the majority of patients (60.4%) within 2 days and in 75% within 3 days, compared with 10.4% and 33.3%, respectively, without treatment and 15% and 40%, respectively, with commonly available treatments. Most patients appreciated the product's ease of application, taste and texture. Aphtarine was well tolerated locally and most patients rated the product good to excellent overall. CONCLUSION: Aphtarine is a safe, well tolerated and highly effective promising new treatment for healing common mouth ulcers.

Thrombin facilitation of voltage-gated sodium channel activation in human cardiomyocytes: implications for ischemic sodium loading.

BACKGROUND: Thrombin plays a role in mediating ischemic injury and cardiac arrhythmias, but the mechanisms involved are poorly understood. Because voltage-gated sodium channels (VGSCs) have not previously been considered, putative effects of thrombin on VGSC function were investigated in human isolated cardiomyocytes. METHODS AND RESULTS: Sodium current (I(Na)) was recorded by the whole-cell patch-clamp method. Thrombin increased peak I(Na) amplitude in an activity-dependent manner, from 1 to 100 U/mL, with an apparent EC50 of 91+/-16 U/mL. When tested at 32 U/mL, thrombin-increased I(Na) was abolished by tetrodotoxin (50 micromol/L). Thrombin effects on I(Na) were reversible and repeatable, and 100 U/mL doubled peak I(Na) amplitude. Thrombin (32 U/mL) shifted I(Na) activation to hyperpolarized potentials without affecting steady-state inactivation, producing unusually large increases in window current. Hirudin (320 U/mL) or haloenol lactone suicide substrate (10 micromol/L) failed to significantly affect these effects of thrombin. In current-clamped cardiomyocytes, thrombin (32 U/mL) depolarized resting membrane potential by 10 mV. CONCLUSIONS: Facilitation of VGSC activation causing large increases in window current is a major mechanism by which thrombin may promote ischemic sodium loading and injury.

Comparison of contractile responses to donitriptan and sumatriptan in the human middle meningeal and coronary arteries.

Donitriptan is a potent, high efficacy agonist at 5-HT(1B/1D) receptors. We investigated the contractile effects of donitriptan and sumatriptan on human isolated blood vessels of relevance to therapeutic efficacy in migraine (middle meningeal artery) and coronary adverse events (coronary artery). Furthermore, using the concentration-response curves in the middle meningeal artery, we predicted the plasma concentration needed for the therapeutic effect of donitriptan. Both donitriptan and sumatriptan contracted the middle meningeal artery with similar apparent efficacy (E(max): 103+/-8% and 110+/-12%, respectively), but the potency of donitriptan (pEC(50): 9.07+/-0.14) was significantly higher than that of sumatriptan (pEC(50): 7.41+/-0.08). In the coronary artery, the contraction to donitriptan was biphasic with a significantly higher maximal response (E(max): 29+/-6%) than sumatriptan (E(max): 14+/-2%; pEC(50): 5.71+/-0.16), yielding two distinct pEC(50) values (8.25+/-0.16 and 5.60+/-0.24). Incubation with the 5-HT(2) receptor antagonist ketanserin (10 microM) eliminated the low affinity component of the concentration-response curve of donitriptan and the resultant E(max) and pEC(50) were 9+/-2% and 7.33+/-0.21, respectively. Ketanserin was without effect on the sumatriptan-induced contraction. Based on the middle meningeal artery contraction, concentrations (C(max)) of donitriptan that may be expected to have a therapeutic efficacy equivalent to that of 50 and 100 mg sumatriptan are predicted to be around 2.5 and 4.3 nM, respectively. Such concentrations are likely to induce only a small coronary artery contraction of 2.9+/-1.5% and 3.8+/-2.0%, respectively; these are not different from those by C(max) concentrations of sumatriptan (1.7+/-0.4% or 2.2+/-0.4%). The present results suggest that, like sumatriptan, donitriptan exhibits cranioselectivity and would be effective in aborting migraine attacks with a similar coronary side-effect profile as sumatriptan.

Effects of Alchemilla vulgaris and glycerine on epithelial and myofibroblast cell growth and cutaneous lesion healing in rats.

Wound-healing properties have been suggested for Alchemilla vulgaris. Since epithelial and myofibroblast cell growth is required for wound healing, the effects of A. vulgaris on cell growth were investigated in Chang liver and Madin Darby Bovine Kidney (MDBK) epithelial cell lines and rat aortic myofibroblast cultures. Putative healing properties were investigated on dorsal circular 8 mm excisional skin lesions in adult male rats. Cell numbers increased with 0.1-1% A. vulgaris, attaining 21.3 +/- 2.1%, 15.5 +/- 2.25% and 10.6 +/- 0.6% in MDBK, myofibroblast and Chang liver cells, respectively (p < 0.005). No morphological changes or cytotoxicity were noted. In rats A. vulgaris (3%)-treated lesions were significantly decreased in diameter by 10.0 +/- 0.7% (p < 0.005) after 2 days of treatment. On day 3 of treatment, the lesion diameter was significantly reduced by 15.9 +/- 1.1% in glycerine vehicle-treated rats compared with distilled water (p < 0.005), whereas that in A. vulgaris-treated rats was reduced further by 23.2 +/- 1.4% (p < 0.005). Glycerine alone significantly reduced the lesion diameter between days 3 and 5 but complete healing occurred a day earlier in A. vulgaris-treated rats. The results demonstrate wound-healing properties of A. vulgaris associated with promitotic activity in epithelial cells and myofibroblasts.

Influence of intermittent compression cuff design on calf deformation: computational results.

The intermittent compression of the calf with an external pressure cuff for the prevention of deep vein thrombosis (DVT) is a well established treatment for surgical patients. The exact mechanisms by which DVT is prevented are poorly understood. This study presents a finite element model of calf cross section, based on MR images of calf geometry, to examine the variation in calf deformation during compression with four different cuff types. Cuff pressure distribution is modelled using interface pressures obtained in a volunteer study. The model has been validated against gross calf deformation obtained from MR images of the compressed calf. This validation has illustrated the importance of out-of-plane boundary conditions, material properties and the variation in cuff loading in the axial direction. In the future this model may have merit in determining optimum pressure loading regimes for Intermittent Pneumatic Compression (IPC) cuff design.

Influence of intermittent compression cuff design on interface pressure and calf deformation: experimental results.

Intermittent pneumatic compression (IPC) is widely used for deep vein thrombosis (DVT) prophylaxis. The technique involves periodic inflation of a compression cuff around a limb, which acts to simulate the muscle pump mechanism, encouraging venous blood flow. However, there is uncertainty regarding the relationship between compression, vascular effects and clinical outcomes. This study investigates calf compression provided by four IPC cuffs with different air bladder configurations. Interface pressure between the cuff and the skin surface is measured and magnetic resonance (MR) images are obtained showing the calf cross section before and during compression. The data will be used to inform numerical simulations of IPC, leading to increased understanding of the implications of cuff design in relation to IPC and DVT prophylaxis.

Evidence for growth-promoting effects of omega n - 3 fatty acids alone and in combination with a specific vitamin and mineral complex in rat neuroblastoma cells.

The beneficial effects of Omega n - 3 polyunsaturated fatty acids (n - 3 PUFA) in situations of cognitive impairment may be associated with enhanced neuronal growth. Since neuronal growth is impaired in n - 3 PUFA deficiency, and enhanced by certain vitamins and trace elements, the effects of n - 3 PUFA, vitamin and mineral cell complex (VMC) and their association on neuronal growth were investigated in cultured rat neuroblastoma cells. Treatment of cells for 3 days with n - 3 PUFA significantly enhanced neurite length without affecting the number of neurites or cells. VMC significantly increased cell number without affecting neurite length or their number. Combined n - 3 PUFA and VMC significantly enhanced all three growth parameters. The data confirm the growth promoting effects of n - 3 PUFA and VMC in cultured neurons over a relatively short time frame.

Donitriptan decreases jugular venous oxygen saturation in rats in the absence of cranial vasoconstriction: an overlooked mechanism of antimigraine action?

The aim of the present study was to determine whether donitriptan and sumatriptan decreased jugular venous oxygen saturation and increased carbon dioxide partial pressure in venous blood. However, previous studies conducted with these compounds cannot discriminate whether the decrease of venous oxygen saturation is dependent of cranial vasoconstrictor. In the present study, vehicle (n = 10), donitriptan (2.5, 10, and 40 microg/kg; n = 8) or sumatriptan (630 microg/kg; n = 8) were infused into the carotid artery in the anesthetized rat. Regional blood flows were evaluated in the presence of donitriptan (10 microg/kg; n = 6) or vehicle (n = 6). Jugular venous oxygen saturation was significantly decreased by donitriptan (from 10 microg/kg) with maximal changes of -32.9 +/- 8.0%. Jugular carbon dioxide partial pressure was increased by donitriptan, reaching maximal changes of 17.7 +/- 4.6% (P < 0.05 versus vehicle). Similarly, sumatriptan significantly decreased venous oxygen saturation and increased jugular carbon dioxide partial pressure. These changes induced by donitriptan are abolished by the 5-hydroxytryptamine (5-HT)(1B/1D) receptor antagonist GR 127935 (N-[4-methoxy-3-(4-methyl-1-piperazinyl)phenyl]-2-[-methyl-4(5-methyl-1,2,4)-oxadiazol-3-yl]-(1,1 biphenyl)-4-carboxamide dihydrochloride). In addition, donitriptan was devoid of significant effects on systemic arterial pressure, heart rate, or regional blood flows, including systemic arterial-jugular venous anastomotic, systemic, or cranial. The results demonstrate that donitriptan increases cerebral oxygen consumption by 5-HT(1B/1D) receptor activation in the absence of cranial vasoconstriction.

Investigation of the effects of naratriptan, rizatriptan, and sumatriptan on jugular venous oxygen saturation in anesthetized pigs: implications for their mechanism of acute antimigraine action.

The effects of naratriptan, rizatriptan, and sumatriptan on arteriovenous oxygen saturation difference and carotid hemodynamics were compared in the anesthetized pig. Oxygen and carbon dioxide partial pressures in systemic arterial and jugular venous blood as well as hemoglobin oxygen saturation were determined by conventional blood gas analysis. Vehicle (n = 19) or naratriptan, rizatriptan, or sumatriptan (0.63, 2.5, 10, 40, 160, 630, and 2,500 microg/kg i.v.; n = 7/group) were infused cumulatively. In naratriptan-, rizatriptan-, and sumatriptan-treated animals, jugular venous oxygen saturation decreased dose dependently (geometric mean ED50 values of 3.1, 17.9, and 16.0 microg/kg, respectively) concomitantly with increases in carotid vascular resistance. Rizatriptan significantly and dose dependently, from 160 microg/kg, increased PvCO2 (P < 0.05 versus vehicle). Naratriptan and sumatriptan also tended to increase PvCO2 albeit nonstatistically significantly. All three triptans consistently evoked quantitatively similar carotid vasoconstriction, whereas decreases in jugular venous oxygen saturation (VOS) and increases in PvCO2 had different magnitudes and occurred only in around one-half of the animals studied. Maximal variations in PvCO2 were found to correlate highly with those in PvO2 (P = 0.002), but maximal variations in carotid resistance failed to correlate with those in PvCO2 (P = 0.76) or PvO2 (P = 0.28). The results demonstrate that the triptans investigated robustly produced carotid vasoconstriction, but elicited less consistent decreases in VOS and increases in jugular PvCO2, possibly suggestive of distinct mechanisms. Collectively, the data suggest that triptan-induced increases in arteriovenous oxygen saturation difference and carbon dioxide partial pressure in venous blood draining the head are class effects.

Anti-ischemic compound KC 12291 prevents diastolic contracture in isolated atria by blockade of voltage-gated sodium channels.

Several lines of evidence support a fundamental role for voltage-gated sodium channels in mediating ischemic Na rise. We examined the effect of the novel anti-ischemic compound KC 12291 on veratridine-stimulated and lysophosphatidylcholine (LPC)-induced sustained sodium current (I(NAL)) mediated by sodium channels in isolated myocytes obtained from guinea-pig atria, by using the whole-cell patch-clamp technique. We also analyzed the effect of KC 12291 on veratridine- and LPC-induced contractures in isolated guinea-pig atria. Veratridine as well as LPC increased I(NAL) measured at 20 ms of a 2 s pulse evoked from -100 to -30 mV (47.5 and 12 pA/pF in the presence of 40 microM veratridine and 10 microM LPC, respectively, vs. 6.7 pA/pF under control conditions). A significant reduction by KC 12291 in the quantity of charge carried by veratridine-stimulated I(NAL) in the range of test potentials between -50 mV and +10 mV was observed and similar effects were obtained on LPC-induced I(NAL). Thus, the quantity of charge carried by LPC-induced I(NAL) over a 2 s pulse to -30 mV was reduced by 48% in the presence of 10 microM KC 12291 vs. a reduction by 50% of veratridine-stimulated I(NAL) at the same test potential. Veratridine- and LPC-induced submaximal contractures in isolated atria were significantly inhibited by KC 12291 in a concentration-dependent manner, with an IC of 0.55 microM and 0.79 microM, respectively. The data indicate that veratridine- and LPC-induced increases in diastolic tension are inhibited by KC 12291 by a mechanism that involves blockade of voltage-gated sodium channels mediating sustained sodium current.

Study of the interaction of lubeluzole with cardiac sodium channels.

The effects of lubeluzole on sodium currents were examined in guinea-pig isolated cardiac myocytes by use of the whole-cell patch clamp technique. Lubeluzole (0.01-100 microM) reduced peak Na+ current (INa) obtained at a holding potential of -80 mV with an IC50 value of 9.5 (3.5-21.9) microM and a Hill coefficient of 1.1. These effects were rapid and reversible. Lubeluzole (10 microM) produced a shift in the inactivation curve to hyperpolarized potentials (by -9.7 mV, P < 0.05), but produced no change in the voltage-dependence of activation. Lubeluzole (10 microM) produced significant tonic block of INa obtained at a holding potential of -120 mV (2.7 +/- 1.4% and 27.5 +/- 5.8% for control and lubeluzole, respectively; n = 6; P < 0.05). Use-dependent block of INa was also observed. Recovery from block was delayed by lubeluzole (10 microM; tau1=4.4 +/- 6.2, tau2=22.7 +/- 1.5 milliseconds for control and tau1=311 +/- 144, tau2 = 672 +/- 23 milliseconds for lubeluzole; n = 6; P < 0.001) confirming use-dependency of block. The results indicate that lubeluzole produces both tonic and use-dependent block of cardiac sodium channels at concentrations similar to those that block neuronal sodium channels, due mainly to interaction of the drug with channels in the inactivated state.

Donitriptan selectively decreases jugular venous oxygen saturation in the anesthetized pig: further insights into its mechanism of action relevant to headache relief.

The effects of donitriptan on systemic arterial-jugular venous oxygen saturation difference were evaluated in pentobarbitone-anesthetized pigs. Oxygen and carbon dioxide partial pressures in systemic arterial and jugular venous blood as well as hemoglobin oxygen saturation were determined by conventional blood gas analysis. Vehicle (40% polyethyleneglycol in saline, n = 9) or donitriptan (0.01, 0.04, 0.16, 0.63, 2.5, 10, and 40 microg/kg, n = 7) were cumulatively infused over 15 min/dose. The involvement of 5-hydroxytryptamine(1B) (5-HT(1B)) receptors was assessed in the presence of the 5-HT(1B/1D) receptor antagonist, GR 127935. Donitriptan decreased markedly and dose dependently jugular venous oxygen saturation [ED(50) 0.5 (0.3-1.1) microg/kg], in parallel with increases in carotid vascular resistance [ED(50) 0.9 (0.7-1.1) microg/kg]. Since arterial oxygen saturation and partial pressure remained unchanged, donitriptan significantly increased arteriovenous oxygen saturation difference from 0.63 microg/kg (maximal variation: 57 +/- 18%, P < 0.05 compared with vehicle). Unexpectedly, donitriptan from 2.5 microg/kg induced marked and significant increases in carbon dioxide partial pressure (pVCO(2)) in venous blood (maximal increase 18.8 +/- 5.7%; P < 0.05 compared with vehicle). Pretreatment with GR 127935 (0.63 mg/kg, n = 5) abolished the fall in venous oxygen saturation and the increase in carotid vascular resistance and reduced the increases in pVCO(2) induced by donitriptan. The results demonstrate that donitriptan, via 5-HT(1B) receptor activation, decreases the oxygen saturation of venous blood draining the head, concomitantly with cranial vasoconstriction. Since donitriptan also increased pVCO(2), an effect upon cerebral oxygen consumption and metabolism is suggested in addition to cranial vasoconstriction, which may be relevant to its headache-relieving effects.

KC 12291: an atypical sodium channel blocker with myocardial antiischemic properties.

KC 12291 was designed as a voltage-gated sodium channel (VGSC) blocker with cardioprotective properties. KC 12291 has moderate inhibitory effects on peak (or rapid) Na+ current, and markedly reduces sustained (or slowly or non-inactivating) Na+ current. This distinguishes KC 12291 from conventional VGSC blockers such as local anesthetics or antiarrhythmics, which have little or no cardioprotective properties. Since VGSCs represent the main pathway for ischemic Na+ loading by failing to inactivate fully, KC 12291 exerts pronounced antiischemic activity principally by reducing the amplitude of sustained Na+ current. In isolated atria and Langendorff-perfused hearts, KC 12291 inhibits diastolic contracture, renowned for its resistance to pharmacological inhibition, reduces ischemic Na+ loading and preserves cardiac energy status. KC 12291 exerts oral antiischemic activity in vivo in the absence of major hemodynamic effects. Cardiac VGSC blockers such as KC 12291, which block cardiac VGSCs in atypical fashion by effectively inhibiting the sustained component of Na+ current, represent, therefore, promising potential antiischemic and cardioprotective drugs.