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Patients suffering an acute myocardial infarction routinely receive morphine and nonsteroidal anti-inflammatory drugs (NSAIDs) alone or in combination. However, the importance of the dose, timing, or the combined administration of both on infarct size reduction has not been assessed. Additionally, it is not known whether morphine or NSAIDs require 12-lipoxygenase (12-LO) to mediate infarct size reduction as found previously for ischemic preconditioning. Male Sprague-Dawley rats were subjected to 30 min of ischemia and 2 h of reperfusion, followed by infarct size assessment (mean +/- S.E.M.%, **P < 0.01). Morphine (0.3 mg/kg), ibuprofen (3 mg/kg), but not aspirin (3 mg/kg) reduced infarct size when administered 5 min before reperfusion compared with vehicle (42.3 +/- 1.5**, 40.8 +/- 2.8**, 60.7 +/- 2.3 versus 59.1 +/- 1.7%, respectively); however, none of these agents reduced infarct size when administered 10 s after reperfusion. Ibuprofen (3 mg/kg) administered with morphine (0.3 mg/kg) reduced infarct size (43.7 +/- 1.3%**), whereas aspirin (1 and 3 mg/kg) abolished morphine-induced infarct size reduction. Morphine (0.2 mg/kg) and ibuprofen (0.6 mg/kg) given at doses not effective individually reduced infarct size when given together (59.0 +/- 1.4, 57.6 +/- 2.8, and 43.9 +/- 1.6%**, respectively). Morphine- and ibuprofen-induced infarct size reduction was abolished by the 12-LO inhibitor baicalein (3 mg/kg) and mimicked by the 12-LO metabolite 12-(S)-hydroxyeicosa-5Z,8Z,10Z,14Z-tetraenoic acid (45.2 +/- 2.5%**). These data suggest that morphine and ibuprofen reduce infarct size individually or at subthreshold doses in combination by 12-LO when administered 5 min before reperfusion. Furthermore, acute aspirin administration has a detrimental interaction with morphine that abrogates morphine-induced infarct size reduction.

A(1) adenosine receptor (AR) antagonists are effective diuretic agents that may be useful for treating fluid retention disorders including congestive heart failure. However, antagonism of A(1)ARs is potentially a concern when using these agents in patients with ischemic heart disease. To address this concern, the present study was designed to compare the actions of the A(1)AR antagonists CPX (1,3-dipropyl-8-cyclopentylxanthine), BG 9719 (1,3-dipropyl-8-[2-(5,6-epoxynorbornyl)]xanthine), and BG 9928 (1,3-dipropyl-8-[1-(4-propionate)-bicyclo-[2,2,2]octyl]xanthine) on acute myocardial ischemia/reperfusion injury and ischemic preconditioning (IPC) in an in vivo dog model of infarction. Barbital-anesthetized dogs were subjected to 60 min of left anterior descending coronary artery occlusion followed by 3 h of reperfusion, after which infarct size was assessed by staining with triphenyltetrazolium chloride. IPC was elicited by four 5-min occlusion/5-min reperfusion cycles produced 10 min before the 60-min occlusion. Multiple-cycle IPC produced a robust reduction ( approximately 65%) in infarct size; this effect of IPC on infarct size was not abrogated in dogs pretreated with any of the three AR antagonists. Surprisingly, in the absence of IPC, pretreatment with CPX or BG 9928 before occlusion or immediately before reperfusion resulted in significant reductions ( approximately 40-50%) in myocardial infarct size. However, treatment with an equivalent dose of BG 9719 had no similar effect. We conclude that the A(1)AR antagonists BG 9719, BG 9928, and CPX do not exacerbate cardiac injury and do not interfere with IPC induced by multiple ischemia/reperfusion cycles. We discuss the possibility that the cardioprotective actions of CPX and BG 9928 may be related to antagonism of A(2B)ARs.

Propafenone is an antiarrhythmic agent with recognized cardiac myocyte repolarizing K+ current inhibitory effects. It has two known electropharmacologically active metabolites, 5-hydroxy- and N-depropylpropafenone, whose K+ current inhibitory effects are less thoroughly elucidated than those of the parent compound. This study characterizes and directly compares the pharmacologic interaction of all three compounds with two key repolarizing K+ currents, the rapidly activating delayed rectifier IKr and the transient outward current Ito, using the whole-cell patch-clamp technique in isolated rabbit ventricular myocytes. All three agents potently inhibited IKr with IC50 values of 0.80 +/-0.14, 1.88 +/-0.21, and 5.78 +/-1.24 microM for propafenone, 5-hydroxypropafenone, and N-depropylpropafenone, respectively, based on reduction of peak tail current amplitude following repolarization from +50 mV to -30 mV. IKr inhibition was concentration- and weakly voltage-dependent, with a time course from channel activation that was well described by a single exponential model and consistent with open channel block. Propafenone and its 5-hydroxy and N-depropyl metabolites also blocked Ito with IC50 values of 7.27 +/-0.53, 40.29 +/-7.55, and 44.26 +/-5.73 microM, respectively, at +50 mV. No significant drug effects were observed with respect to Ito voltage dependence of steady-state inactivation or time course of recovery from inactivation. The preferential interaction of propafenone and its metabolites with IKr relative to Ito in ventricular myocytes sheds new light on the anti- and proarrhythmic activity of propafenone in vivo.

We investigated the possibility that opioids activate a tyrosine kinase (TK) that mediates cardioprotection in an in vivo rat model of myocardial infarction. All animals underwent 30 min of regional ischemia and 2 h of reperfusion. Infarct size was expressed as a percentage of the area at risk (IS/AAR). Control animals had an IS/AAR of 58.2 +/- 0.6. Cardioprotection was induced with the delta1- or delta1/delta2-selective opioid agonists, TAN-67, or D-Ala D-Leu enkephalin (DADLE). Both significantly reduced IS/AAR (28.8 +/- 3.6 and 34.8 +/- 3.8, respectively). The general TK inhibitor, genistein, abolished cardioprotection produced by TAN-67 or DADLE (59.1 +/- 3.2 and 61.5 +/- 3.4, respectively), whereas the structural analog, daidzein, lacking TK inhibitory activity, did not. Interestingly, the selective Src/epidermal growth factor (EGF) receptor TK inhibitor, lavendustin A, did not abolish TAN-67-induced cardioprotection (22.1 +/- 6.8). Similarly, the Src-selective TK antagonist, PP2, had no effect on DADLE-induced cardioprotection (31.1 +/- 7.3). These unexpected findings suggest that Src and EGF receptor TKs are not important in the genesis of cardioprotection produced by TAN-67. Finally, we demonstrate that genistein did not affect protein kinase C (PKC) translocation induced by TAN-67. These data suggest that a TK, but most likely not an Src/EGF receptor TK, is important in cardioprotection via opioid receptor stimulation and that the pathway for TK activation is downstream from or parallel to PKC activation in the in situ rat heart since genistein could not affect PKC translocation of selective isoforms induced by TAN-67 and assessed by immunohistochemistry.

The antiarrhythmic agent propafenone and its primary electropharmacologically active metabolite, 5hydroxypropafenone, are known inhibitors of cardiac myocyte repolarizing currents. We recently documented potent propafenone inhibition of the transient outward potassium current Itoin human atrial myocytes from patients in the newborn and infant age range. In the current study we characterized ventricular Itoinhibition by propafenone and 5hydroxypropafenone in neonatal myocytes enzymatically isolated from 2dayold SpragueDawley rat pups. Using the wholecell patchclamp technique in ventricular myocytes kept in primary culture for 1–4 days, we observed comparably potent Itoinhibition by both agents, yielding 50 maximal inhibitory concentration IC50values of 2.1 ± 0.5 and 1.5 ± 0.2 Mfor propafenone and 5hydroxypropafenone, respectively. Itoblockade by both of these agents was time, concentration, and voltage dependent, but use independent. There was no drug effect on steadystate voltage dependence of Itoinactivation, or on the time course of Itorecovery from inactivation. These findings are consistent with an open channelblocking mechanism as suggested by other models. We conclude that both propafenone and 5hydroxypropafenone are potent Itoinhibitors in neonatal rat ventricular myocytes, with potencies exceeding those demonstrated for propafenone in adult rat ventricular myocytes or in human atrial myocytes from patients of all ages.

Stimulation of the delta(1)-opioid receptor has been shown to trigger ischemic preconditioning (IPC). Additionally, myocardial ischemia/reperfusion induces the activation of extracellular signal-regulated kinase (ERK). Therefore, we examined the role of ERK in acute cardioprotection induced by delta(1)-opioid receptor stimulation or IPC. Infarct size (IS) was expressed as a percentage of the area at risk (AAR). Control animals had an IS/AAR of 60.6 +/- 1.8. IPC and delta(1)-opioid receptor stimulation with TAN-67 reduced IS/AAR (8.2 +/- 1.3 and 30.2 +/- 2.4). Inhibition of ERK with the selective MEK-1 antagonist, PD 098059 during IPC or TAN-67 administration significantly reduced cardioprotection (41.5 +/- 6.4 and 63.0 +/- 4.8). Western Blot analysis and subsequent densitometry corroborated these observations. Control, TAN-67-, or IPC-treated hearts were harvested after 0, 5, 15, and 30 min of ischemia or 5, 30, and 60 min of reperfusion and separated into cytosolic and nuclear fractions. Both isoforms of ERK (p44 and p42) rapidly increased to greater levels throughout reperfusion in the nuclear fraction of IPC- and opioid-treated versus control rats, however, this increase was not attenuated by PD 098059. Conversely, the rapid activation of the 44-kDa isoform of ERK after 5 min of reperfusion in the cytosolic fraction was significantly increased in IPC- and opioid-treated hearts versus control, and this increase was abolished by pretreatment with PD 098059. Additionally, p42 was activated in the cytosolic fraction of IPC-treated animals. These results suggest a key role for the 44-kDa isoform of ERK in the cytoplasm during cardioprotection induced by either IPC or stimulation of the delta(1)-opioid receptor.

We examined the role of the sarcolemmal and mitochondrial ATP-sensitive potassium (K(ATP)) channel in a rat model of myocardial infarction after stimulation with the selective delta(1)-opioid receptor agonist TAN-67. Hearts were subjected to 30 min of regional ischemia and 2 h of reperfusion. Infarct size was expressed as a percentage of the area at risk. TAN-67 significantly reduced infarct size/area at risk (29.6 +/- 3.3) versus control (63. 1 +/- 2.3). The sarcolemmal-selective K(ATP) channel antagonist HMR 1098, administered 10 min before TAN-67, did not significantly attenuate cardioprotection (26.0 +/- 7.3) at a dose (3 mg/kg) that had no effect in the absence of TAN-67 (56.3 +/- 4.3). Pretreatment with the mitochondrial selective antagonist 5-hydroxydecanoic acid (5-HD) 5 min before the 30-min occlusion completely abolished TAN-67-induced cardioprotection (54.3 +/- 2.7), but had no effect in the absence of TAN-67 (62.6 +/- 4.1), suggesting the involvement of the mitochondrial K(ATP) channel. Additionally, we examined the antiarrhythmic effects of TAN-67 in the presence or absence of 5-HD and HMR 1098 during 30 min of ischemia. Control animals had an average arrhythmia score of 10.40 +/- 2.41. TAN-67 significantly reduced the arrhythmia score during 30 min of ischemia (2.38 +/- 0. 85). 5-HD and HMR 1098 in the absence of TAN-67 produced an insignificant decrease in the arrhythmia score (8.80 +/- 2.56 and 4. 20 +/- 1.07, respectively). 5-HD administration before TAN-67 treatment abolished its antiarrhythmic effect (4.71 +/- 1.11). However, HMR 1098 did not abolish TAN-67-induced protection against arrhythmias (1.67 +/- 0.80). These data suggest that delta(1)-opioid receptor stimulation is cardioprotective against myocardial ischemia and sublethal arrhythmias and suggest a role for the mitochondrial K(ATP) channel in mediating these cardioprotective effects.

Administration of inhibitors of the Na+/H+ exchanger (NHE) have been shown to produce cardioprotective effects in a number of animal models of ischemia-reperfusion injury; however, controversy still exists as to the efficacy of these agents when administered just before reperfusion. To address this question, the efficacy of several doses of a new selective NHE-1 isoform inhibitor (IC50 for inhibition of 22Na uptake in NHE-1 expressing mouse fibroblast cells = 10.4 +/- 1.0 nM), EMD 85131 (2-methyl-5-methylsulfonyl-1-(1-pyrrollyl)-benzoyl-guanidine), was tested in a canine infarct model in which the left anterior descending coronary artery was occluded for 60 min followed by 3 hr of reperfusion. EMD 85131 (0.75 or 3.0 mg/kg) was infused for 15 min before left anterior descending occlusion or 15 min before reperfusion. Infarct size was determined by use of the triphenyltetrazolium chloride histochemical stain and was expressed as a percent of the area at risk. EMD 85131 (0.75 or 3.0 mg/kg) administered before left anterior descending occlusion produced a marked (*P < .05) and dose-related reduction in IS/AAR (24.3 +/- 3.6, control; 9.3 +/- 3.4%, EMD 0.75; 6.4 +/- 2.3%, EMD 3.0). These two doses of EMD also produced significant (*P < .05) reductions in infarct size/area at risk (12.2 +/- 2.1%, EMD 0.75; 13.0 +/- 2.9%, EMD 3.0) when administered 15 min before reperfusion. These results suggest that selective NHE-1 inhibitors are able to markedly reduce infarct size when given before or during ischemia and also suggest that these compounds may have clinical utility when administered after the initiation of an ischemic insult.

Fluorescence ratiometric imaging of Lilium pollen tubes loaded with the Ca2+ indicator Fura-2 dextran has revealed a distinct elevation of free intracellular calcium ion concentration ([Ca2+]i) at the extreme tip of actively growing Lilium pollen tubes that declines to a uniform basal level of 170 nM throughout the length of the tube. The calcium gradient occurs within the first 10–20 μm proximal to the tip. Experimental inhibition of tip growth, usually achieved through the injection of the Ca2+ buffer 5,5′-dibromo BAPTA, results in the loss of the [Ca2+]i gradient. Occasionally these inhibited cells reinitiate growth, and when they do so ratio imaging reveals that the tip gradient of free [Ca2+]i re-emerges. The results presented here are very different from those previously published by revealing the presence of the [Ca2+]i gradient that is restricted to the 10–20 μm adjacent to the tube tip. Further, these experiments demonstrate a strict correlation between the presence of a [Ca2+]i gradient, and tip growth in Lilium pollen tubes.

There has been controversy regarding whether ATP-sensitive potassium channel activation protects hearts through adenosine A1 receptor activation or the converse. We addressed this issue by determining the effect of the adenosine A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) on the cardioprotective activity of the ATP-sensitive potassium channel opener bimakalim. In isolated rat hearts subjected to 25 min of global ischemia and 30 min of reperfusion, bimakalim significantly reduced lactate dehydrogenase release and improved postischemic recovery of contractile function. Bimakalim increased the time to the onset of ischemic contracture (EC25 = 1.2 microM), compared with vehicle, and 10 microM DPCPX had no effect on this protective action (EC25 = 1.1 microM). The 10 microM concentration of DPCPX was sufficient to abolish the bradycardic and cardioprotective effects of the adenosine A1 receptor agonist (R)-(-)-N6-(2-phenylisopropyl)adenosine. DPCPX alone had no effect on the severity of ischemia/reperfusion damage. Glyburide completely abolished the cardioprotective effects of bimakalim. Bimakalim (1 microg/kg, intracoronarily) given over four periods of 5 min, interspersed with 10-min drug-free periods, before a 60-min occlusion and 3-hr reperfusion significantly reduced infarction size in anesthetized dogs (25 +/- 5 and 8 +/- 2% of the left ventricular area at risk for vehicle- and bimakalim-treated groups, respectively). DPCPX had no effect on the infarction-sparing activity of bimakalim (9 +/- 3% of the left ventricular area at risk). The protective effect of bimakalim was not accompanied by marked hemodynamic changes or by changes in regional myocardial blood flow. The results of this study suggest that the cardioprotective effects of ATP-sensitive potassium channel openers are not dependent on adenosine A1 receptor activation in rat or dog models of ischemia.

Context. Pheochromocytomas are hormone secreting tumors of the medulla of the adrenal glands found in 0.1–0.5% of patients with hypertension. The vast majority of pheochromocytomas secrete catecholamines, but they have been occasionally shown to also secrete interleukins, calcitonin, testosterone, and in rare cases adrenocorticotropic hormone. Pheochromocytoma crisis is a life threatening event in which high levels of catecholamines cause a systemic reaction leading to organ failure. Case Description. A 70-year-old man was admitted with acute myocardial ischemia following glucocorticoid administration as part of an endocrine workup for an adrenal mass. Cardiac catheterization disclosed patent coronary arteries and he was discharged. A year later he returned with similar angina-like chest pain. During hospitalization, he suffered additional events of chest pain, shortness of breath, and palpitations following administration of glucocorticoids as preparation for intravenous contrast administration. Throughout his admission, the patient demonstrated both signs of Cushing’s syndrome and high catecholamine levels. Following stabilization of vital parameters and serum electrolytes, the adrenal mass was resected surgically and was found to harbor an adrenocorticotropic hormone secreting pheochromocytoma. This is the first documented case of adrenocorticotropic hormone secreting pheochromocytoma complicated by glucocorticoid induced pheochromocytoma crisis. Conclusion. Care should be taken when administering high doses of glucocorticoids to patients with suspected pheochromocytoma, even in a patient with concomitant Cushing’s syndrome.

We discuss a full three-dimensional model of an ultra-small MOSFET, in which the transport is treated by a coupled EMC and molecular dynamics (MD) procedure to treat the Coulomb interaction in real space. The inclusion of the proper Coulomb interaction affects both the energy and momentum relaxation processes, but also has a dramatic effect on the characteristic curves of the device. We find that the short-range e–e and e–i terms, combined with discrete impurity effects, is also needed for accurate measurement of the device threshold voltage.

We present a 3D Ensemble Monte Carlo particle-based simulator with a novel realspace treatment of the short-range electron – electron and electron-ion interactions. By using a corrected Coulomb force in conjunction with a proper cutoff range, the shortrange portion of the force is properly accounted for, and the ‘double counting’ of the long-range interaction is eliminated. The proposed method naturally incorporates the multi-ion contributions, local distortions in the scattering potential due to the movement of the free charges, and carrier-density fluctuations. The doping dependence of the low-field mobility obtained from 3D resistor simulations closely follows experimental results, thus supporting the appropriateness of the proposed scheme. Simulations of ultra-small MOSFETs demonstrate that the short-range electron – electron and electronion interactions are responsible for the fast thermalization of the carriers at the drain end of the device, which occurs over distances that are on the order of few nanometers. The omission of the short-range portions of these two interaction terms leads to significant overestimation of the distance over which carriers thermalize.

Malassezia furfur and Candida albicans are fungal pathogens which have been recognized with increasing frequency as agents of mortality and serious morbidity in neonatal intensive care unit patients. A longitudinal study of oral, rectal and umbilical colonization by these organisms of newborns admitted to a neonatal intensive care unit within 24 h of birth was undertaken. Of 71 infants followed for a minimum of 10 days, 24 were colonized with M furfur and 12 with C albicans during the first 10 days of life. The lower gastrointestinal tract was found to be the most common colonization site for both organisms. Statistically significant (P<0.05) inverse associations were demonstrated between gestational age and risk of colonization with either organism at any site, and between birthweight or gestational age and risk of rectal colonization with either organism. Antibiotics were associated with a relative risk colonization of 4.06 (P=0.06) with either organism at any site. It is concluded that M furfur and C albicans are common colonizing organisms in a neonatal intensive care unit setting and are most frequently harboured in the lower gastrointestinal tract. M furfur, recently implicated as a systemic pathogen in this population, has not been previously recognized as a gastrointestinal commensal organism. The relationship between colonization and invasive fungal disease, and potential roles for preventive strategies, remain to be elucidated.

As semiconductor technology continues to evolve, numerical modeling of semiconductor devices becomes an indispensible tool for the prediction of device characteristics. The simple drift-diffusion model is still widely used, especially in the study of subthreshold behavior in MOSFETs. The numerical solution of these two equations offers difficulties in small devices and special methods are required for the case when dealing with 3D problems that demand large CPU times. In this work we investigate the convergence properties of the Bi-CGSTAB method. We find that this method shows superior convergence properties when compared to more commonly used ILU and SIP methods.