bluuebunny/crossref_metadata_2025 huggingface dataset:
Chronic potentiation of vasoconstrictor hypertension by adrenocorticotropic hormone.
Authors: Lohmeier T E , Carroll R G
Published: August 2012

The chronic effects of ACTH on mean arterial pressure (MAP) and related variables were studied in dogs with both chronic norepinephrine (NE)- and chronic aldosterone-induced hypertension. MAP was recorded continuously for 24 hours/day, and sodium intake was 71 mEq/day. ACTH was infused for 8 days at a rate that does not increase MAP in normotensive dogs and yet a rate that produces pronounced mineralocorticoid and glucocorticoid effects. Chronic ACTH infusion in dogs with NE hypertension caused natriuresis, kaliuresis, diuresis, hypernatremia, hypokalemia, and suppression of PRA; additionally, there was either no net change in water balance or net water balance was positive. However, in marked contrast to dogs without pre-existing hypertension, in dogs with NE hypertension ACTH produced a pronounced additional increase in MAP of 39 to 63 mm Hg. Although ACTH markedly potentiated NE hypertension, high infusion rates of aldosterone (+6 mm Hg) and cortisol (-7 mm Hg) had relatively weak effects on MAP; further, in dogs with NE hypertension, the increase in MAP associated with simultaneous infusions of high rates of cortisol and aldosterone was equal to only approximately half of that produced by ACTH. In dogs with aldosterone hypertension, the changes in salt and water balance produced by ACTH were comparable to those that occurred when ACTH was administered to dogs with NE hypertension. In dogs with aldosterone hypertension, however, ACTH did not produce kaliuresis, hypernatremia, or hypokalemia; moreover, ACTH did not exacerbate aldosterone hypertension. Thus, the data indicate that the hypertensive effects of ACTH are manifested in conditions of reduced renal excretory capacity such as exist when plasma levels of the potent sodium -retaining hormone NE are inappropriately elevated. Finally, the hypertensive effects of ACTH cannot be accounted for simply on the basis of enhanced mineralocorticoid and glucocorticoid activity.
Altered renal alpha 2-adrenergic receptor regulation in genetically hypertensive rats.
Authors: Pettinger W A , Sanchez A , Saavedra J , Haywood J R , Gandler T , Rodes T
Published: August 2012

Renal alpha 1 and alpha 2-adrenergic receptors were quantified in Dahl salt-sensitive and salt-resistant rats, in Okamoto-Aoki spontaneously hypertensive rats (SHR), in Wistar Kyoto "normotensive" (WKY), and in Charles River rats made hypertensive by the Grollman ligature technique and by DOC-NaCl administration after unilateral nephrectomy. The effect of high dietary NaCl on renal alpha receptors was studied in Dahl, SHR, and WKY rats. Renal alpha 1 and alpha 2 receptor densities were higher (p less than 0.05) in SHR and in Dahl salt-sensitive rats than in their normotensive controls. High dietary sodium increased renal alpha 2 receptors and blood pressure in SHR, WKY and Dahl salt-sensitive, but not in resistant Dahl rats. A study of time relationships revealed that the increase in renal alpha 2 receptors preceded most of the blood pressure elevation due to high dietary sodium. Renal alpha-adrenergic receptor densities of surgical (Grollman) and endocrine (DOC-NaCl) forms of rat hypertension were not different from normotensive controls. Thus, renal alpha 2 receptor density and increase thereof by dietary sodium may be: 1) a biochemical marker for genetic forms of hypertension in the rat, and 2) closely linked to the basic mechanism of high blood pressure.
Myosin phosphorylation and crossbridge regulation in arterial smooth muscle. State-or-the-art review.
Authors: Murphy R A
Published: August 2012

Regulation of vascular resistance is generally explained in terms of neural, hormonal, metabolic, and myogenic factors altering intracellular calcium [Ca++] in vascular smooth muscle. Ca++ acts as a second messenger regulating the number of active crossbridges and force generation by binding to a myofilament regulatory protein. A search for the Ca++-binding regulatory protein in arterial smooth muscle has uncovered what appears to be a new type of regulation. In addition to its interaction with an undefined Ca++-binding site which determines force development, Ca++ stimulates phosphorylation of the crossbridges. Phosphorylated crossbridges cycle more rapidly than dephosphorylated crossbridges in the presence of Ca++. Some known characteristics of the myosin light chain kinase/phosphatase system and the effects of crossbridge phosphorylation on the mechanics of arterial smooth muscle are described. Chronic alterations in this system have potential effects on vascular resistance and merit investigation in studies of arterial smooth muscle from hypertensive animal models.
Acute and short-term effects of new calcium antagonist in hypertension.
Authors: Burris J F , Notargiacomo A V , Papademetriou V , Freis E D
Published: August 2012

Nitrendipine (Bay e 5009) is a new calcium antagonist antihypertensive agent similar in structure and function to nifedipine. Nitrendipine was tested in a range of single and repeated doses in 10 adult males with uncomplicated mild to moderate hypertension. The treatment goal was reduction of diastolic blood pressure to 90 mm Hg or less. The dose that achieved goal blood pressure ranged between 10 and 30 mg. Systolic and diastolic blood pressure began to fall within 15 minutes following ingestion of single oral doses of nitrendipine. The maximum effect of the drug was achieved in 60 to 90 minutes and remained at approximately this level for 6 to 8 hours. The average reduction in supine diastolic was more than twice as great as the fall in systolic blood prere began to fall within 15 minutes following ingestion of single oral doses of nitrendipine. The maximum effect of the drug was acheived in 60 to 90 minutes and remained at approximately this level for 6 to 8 hours. The average reduction in supine diastolic was more than twice as great as the fall in systolic blood pressure. With continuous doses given three times daily, all patients' blood pressures were as low or lower than the maximal effect observed after single doses. The reduction in blood pressure was sustained for the full 3 weeks of treatment. There was a sustained small increase in pulse rate averaging 6 beats/min. The drug was generally well tolerated by most patients. Mild to moderate headache that resolved with continued treatment was the most frequent side effect. This preliminary trial indicates that nitrendipine is an effective antihypertensive agent that merits further study.
Decreased vascular responsiveness produced by angiotensin-converting enzyme inhibitors in the rat isolated kidney.
Authors: Chiba S , Quilley C P , McGiff J C
Published: August 2012

The effects of three angiotensin converting enzyme (ACE) inhibitors - captopril, MK-421 diacid, and teprotide - on renal vascular responses to graded (50, 100, 200 ng) injections of norepinephrine (NE) were examined in rat isolated perfused kidneys, having a mean basal perfusion pressure of 78 +/- 10 mm Hg. The minimum dose of captopril (0.05 microgram/ml, low dose) that abolished the vasoconstrictor responses to 100 and 200 ng angiotensin I did not affect NE-induced renal vasoconstriction, whereas a dose 100 times greater (high-dose captopril, 5 micrograms/ml) reduced the vasoconstrictor action of NE. MK-421 diacid also at high dose (1 microgram/ml), caused similar reduction in renal vasoconstrictor responses to NE. In contrast, a high dose of teprotide (50 micrograms/ml) did not affect renal vascular responsiveness to NE. The threshold dose of NE that released prostaglandins, measured by bioassay, was 50 ng. Indomethacin (1 microgram/ml) prevented NE-induced release of prostaglandins but did not affect the ability of captopril to attenuate NE-induced vasoconstriction. We conclude that captopril and MK-421 diacid decreases vascular reactivity in the rat isolated kidney by a mechanism independent of ACE inhibition and unrelated to a prostaglandin-dependent vascular mechanism. Moreover, the presence of mercapto function in the ACE inhibitor is not essential since captopril, which has a sulfhydryl group, and MK-421 diacid, which lacks this group, have similar effects on renal vascular responsiveness.
Purification and characterization of one-chain and two-chain renins from mouse submandibular gland.
Authors: Pratt R E , Dzau V J
Published: August 2012

Biosynthetic processing of mouse submandibular gland renin involved sequential proteolytic cleavages of preprorenin to prorenin; the prorenin, in turn, rapidly converted to one-chain and slowly to two-chain renins that were both enzymatically active. One-chain and two-chain renins were purified by an eight-step purification including carboxymethyl cellulose and high performance liquid chromatography (HPLC). The specific activity of the purified one-chain renin was fivefold higher than the two-chain renin. Purified heavy-chain renin was obtained by dithiotreitol incubation of two-chain renin. The heavy chain, isolated by HPLC, retained less than 4% of the activity of the native two-chain, indicating that light-chain renin is essential for enzymatic activity. Previous data indicate that both one-chain and two-chain renins are secreted. One-chain renin is immediately secreted into the media after synthesis, whereas two-chain renin is secreted later. These results suggest that renin may be secreted by two separate pathways--an early pathway from the golgi and another pathway from the secretory granules. Our data indicate that renin biosynthesis and secretion are complex and may be controlled at multiple points.
Postsynaptic alpha 2-adrenergic receptor-mediated vasoconstriction in SHR tail arteries in vitro.
Authors: Hicks P E , Medgett I C , Langer S Z
Published: August 2012

In isolated perfused tail arteries of spontaneously hypertensive rats (SHR), the selective alpha 2-adrenergic receptor antagonist idazoxan ( RX781094 ) at low concentrations antagonized vasoconstrictor responses induced by norepinephrine (NE) and low frequency periarterial field stimulation. The vasoconstrictor responses to the selective alpha 2-adrenergic receptor agonist TL99 or to phenylephrine were also antagonized by low concentrations of idazoxan . In contrast, idazoxan did not antagonize responses induced by the alpha 1-adrenergic receptor agonists amidephrine or methoxamine in perfused tail arteries of SHR. The alpha 1-adrenergic receptor antagonist prazosin was very potent against methoxamine or phenylephrine and responses to periarterial field stimulation in SHR and Wistar-Kyoto (WKY) rat tail arteries, but only showed a modest selectivity for TL99 -induced responses in SHR arteries. The results support the contention that postjunctional alpha 2-adrenergic receptors can be demonstrated in arterial smooth muscle in vitro and are particularly evident in arteries from hypertensive animals. In SHR tail arteries, postsynaptic alpha 2-adrenergic receptors contribute to the vasoconstrictor responses to exogenous NE and may be activated by endogenously released NE.
Regulation of alpha 1-adrenergic receptor-coupled calcium flux in cultured vascular smooth muscle cells.
Authors: Colucci W S , Brock T A , Gimbrone M A , Alexander R W
Published: August 2012

To study the role of the alpha-adrenergic receptor (AAR) pathway in the regulation of catecholamine-induced vascular contraction, we developed methods for the direct evaluation of AAR and AAR-coupled calcium efflux in cultured vascular smooth muscle cells derived from the rabbit aorta by enzymatic dissociation. AAR were characterized by the binding of the alpha 1- and alpha 2-selective radioligands [3H]-prazosin and [3H]-yohimbine, respectively. Norepinephrine-stimulated efflux of 45calcium from preloaded cells was measured as an index of AAR-mediated calcium flux. The [3H]-prazosin binding was of high affinity (Kd = 0.15 nM), saturable (Bmax = 75-125 fmol/mg protein), and competed for by agonists and antagonists in the order expected for an alpha 1 receptor. There was no specific binding of [3H]-yohimbine. Norepinephrine-stimulated 45Ca efflux was concentration-dependent (EC50 congruent to 100 nM), and potently blocked by prazosin (IC50 congruent to 0.1 nM), but not yohimbine (IC50 greater than 100 nM), indicating, together with the binding data, that norepinephrine-stimulated 45Ca efflux in this system is alpha 1 mediated. Following treatment of cells with 1-norepinephrine (0.1 nM) for 24 hours, the density of AAR and maximal norepinephrine-stimulated 45Ca efflux were decreased by 72% +/- 14% and 91% +/- 9%, respectively. This cultured cell system offers several advantages for study of the mechanisms of coupling and regulation of alpha-adrenergic receptors in vascular smooth muscle.
Effect of ouabain on arteriolar responses to norepinephrine in chronic, benign, volume-expanded hypertension.
Authors: Overbeck H W
Published: August 2012

We have reported increases in ouabain-sensitive Rb+ uptake by freshly excised conduit arteries from volume-expanded Dahl salt-sensitive (S) rats and also from rats with chronic (4 to 6 weeks), benign (serum creatinine less than 1.4 mg%) one-kidney, one clip ( 1K1C ) hypertension on high NaCl intake. To assess in vivo arteriolar function in this latter model, and a role for putative circulating ouabain-like factors, we perfused the maximally vasodilated (nitroprusside, 0.015 mg/ml limb blood), vascularly isolated, innervated hindlimb vascular beds of chloralose-anesthetized, water- or saline-drinking 1K1C hypertensive rats with their own blood at 1 ml/min, and measured limb responses to i.a. norepinephrine 0.004 to 128 micrograms, before and during local infusion of ouabain (achieving 2.5 X 10(-5) M in limb blood). Complete dose-response curves in eight 1K1C hypertensive rats were steeper and higher than those in five uninephrectomized (1K) normotensive control rats. However, threshold and ED50 were unchanged. Thus, alterations in the curve in the hypertensive rats represented only structural vascular changes. Ouabain evoked a leftward shift of the dose-response curve in an additional 18 1K1C hypertensive rats and 13 1K normotensive controls. In the hypertensive rats as compared to the controls, there were trends for increases, rather than decreases, in the ouabain-induced shift of the curve. Shifts in 14 rats with chronic 2K1C hypertension did not differ from those in the 1K1C hypertensive rats. Together, these studies in chronic, presumably volume-expanded, low-renin hypertension unaccompanied by renal insufficiency provide no evidence for physiologically significant inotropic effects of circulating ouabain-like pump inhibitor.
Functional evidence for increased sodium permeability in aortas from DOCA hypertensive rats.
Authors: Moreland R S , Lamb F S , Webb R C , Bohr D F
Published: August 2012

We studied the role of increased Na+ permeability on the increased responsiveness to ouabain and to K+-free solution in aortas from DOCA hypertensive rats. Helically cut strips from DOCA hypertensive and normotensive control rats were mounted in a muscle bath for recording isometric force. In response to ouabain, aortas from DOCA hypertensive rats were significantly more sensitive and developed a greater maximal force than aortas from control rats. The rate of force development in response to K+-free solution was significantly faster in aortas from DOCA hypertensive rats as compared to those from control rats. Monensin (10(-5)M), a Na+ ionophore, increased the contractile response to ouabain and the rate of force development in response to K+-free solution in both DOCA hypertensive and control aortas. Amiloride (3 X 10(-5) M), a Na+ channel blocker, decreased the contractile response to ouabain and the rate of force development to a K+-free solution in both the DOCA hypertensive and control aortas, but the magnitude of decrease was greater in aortas from DOCA hypertensive rats. Thus, a Na+ ionophore causes the control aortas to perform like those from DOCA hypertensive rats, and a Na+ channel blocker causes aortas from DOCA hypertensive rats to perform like those from control rats. It is concluded that the difference between the two is that the smooth muscle of aortas from DOCA hypertensive rats is more permeable to Na+ than is that from control rats.
Vascular, volume, and cardiac response to normal and hypertensive pregnancy.
Authors: Hunyor S N
Published: August 2012

Cardiovascular adaptations to the circulatory and volume changes of pregnancy have been studied in late normal and hypertensive pregnancy and postpartum. There has been evidence of a marked plasma volume expansion in normal pregnancy, blunted in preeclampsia; an increased capillary permeability during normal pregnancy; augmented left ventricular mass, which is increased in mild preeclampsia; and similar increases in peripheral venous distensibility during normal and preeclamptic pregnancy. In mild preeclampsia the enlarged ventricle has been shown to be capable of maintaining a normal cardiac output despite elevated afterload. The forearm vascular bed appears to play little part in these adjustments, because forearm venous distensibility has been shown to be higher during normal pregnancy than during postpartum; in hypertensive individuals there was no difference during pregnancy and postpartum. It is evident from this brief review that it is too early to draw clear-cut conclusions regarding the vascular, volume, and cardiac response to normal and hypertensive pregnancy. Research in this field, including two-dimensional echocardiography and plethysmography in larger homogeneous groups, will probably lead to a better understanding of the pathophysiological mechanism of pregnancy hypertension.
Reversal of cardiac hypertrophy in humans.
Authors: Tarazi R C , Fouad F M
Published: August 2012

Reversal of left ventricular (LV) hypertrophy has definitely been proved to follow effective blood pressure control in hypertensive patients. This reduction in cardiac mass does not depend solely on blood pressure levels as measured in routine follow-up; it varies markedly with the type of drug used and even among patients treated with the same antihypertensive agent. The factors influencing the degree of regression of hypertrophy include stability of blood pressure control (entailing diurnal variations and response to stress), neurohumoral disturbances or fluid retention induced by the antihypertensive drug, and the presence of associated cardiac disease, as well as individual variations such as genetic background and possibly age. LV performance at rest was not depressed by the reduction in cardiac mass but remained normal in relation to changes in LV end-systolic stress.
Hemodynamic effects of antihypertensive drugs. Possible implications for the prevention of atherosclerosis.
Authors: Spence J D
Published: August 2012

By lowering blood pressure, a number of hypertensive complications can be prevented, including congestive heart failure and such consequences of hypertensive arteriolar disease as nephropathy, intracerebral hemorrhage, and lacunar stroke. Whether atherosclerotic complications such as myocardial infarction can be prevented is more problematic and may depend on effects of the antihypertensive drugs other than the reduction of blood pressure, such as effects on plasma lipids and possibly hemodynamic effects. The following discussion summarizes a series of studies that suggest that the hemodynamic effects of antihypertensive drugs may be an important aspect of this problem. In studies in rhesus monkeys and hypertensive patients, antihypertensive drugs were shown to have differing effects on blood velocity and heart rate, important parameters in the genesis of arterial flow disturbances. In patients with carotid stenosis, hydralazine increased, whereas propranolol reduced, the occurrence of abnormal high-velocity flow patterns associated with turbulence and vortex formation. In a hypertensive (one kidney, one-clip) cholesterol-fed rabbit model, propranolol was significantly more effective than hydralazine in preventing the occurrence of aortic atherosclerosis. These observations suggest that the cardioprotective effect of beta blockers may extend to an antiatherosclerotic effect by hemodynamic mechanisms. This hypothesis is being further tested in patients with carotid stenosis.
Effects of antihypertensive treatment on prognosis.
Authors: Berglund G
Published: August 2012

Knowledge of the benefit of antihypertensive treatment relies on several large-scale trials, such as the Veterans Administration (VA) Studies, the Hypertension Detection and Follow-up Program (HDFP), the Australian National Blood Pressure Study (ANBP Study), and the Gothenburg Primary Preventive (GPP) study. These studies have shown that antihypertensive drugs decrease the incidence of directly hypertension-related complications like stroke, cardiac decompensation, and accelerating hypertension. It is less clear whether they influence the incidence of coronary events. In the HDFP, the ANBP Study, and the GPP study, the participants were recruited by screening large proportions of the total population. The proportion of the total screened population who met the inclusion criteria and hence were included was 3.3% in the ANBP, 6.9% in the HDFP, and 13.6% in the GPP trial. In most Western countries a substantially larger proportion of the total population is already being treated for hypertension. It is therefore not possible to use the results of these studies to justify treatment of larger segments of the population than we treat today. This is especially important because the milder the hypertension, the less effective the treatment is; hence, more patients will be given treatment without deriving benefit from it.
Humoral trophic influence on cardiovascular structural changes in hypertension.
Authors: Yamori Y , Igawa T , Tagami M , Kanbe T , Nara Y , Kihara M , Horie R
Published: August 2012

Since the early development of structural cardiovascular change in spontaneously hypertensive rats (SHR) and stroke-prone SHR (SHRSP) indicated the involvement of non-pressure-dependent factors in this process in hypertension, smooth muscle cells (SMC) from the aorta of SHR, SHRSP, and normotensive Wistar-Kyoto rats (WKY) were investigated under tissue culture conditions free from blood pressure and humoral factors in vivo. By the observation of such factors as growth rate and DNA or protein synthesis vascular SMC from these rats with genetic hypertension were proved to have intrinsically greater growth activity independently of blood pressure. Although serum from SHR and SHRSP had no specific stimulative effect on SMC growth, circulating epinephrine may accelerate cardiovascular structural changes because isoproterenol added to the culture media enhanced ornithine decarboxylase (ODC) activity. Moreover, SMC from SHR and SHRSP showed greater thymidine incorporation than those from WKY even in response to lower extracellular Na+ concentration. Local nutritional conditions of SMC, which were proved to have a great effect on the morphology and structure of cultured SMC, may be a basic determinant of the development of hypertension-induced structural vascular changes or lesions.
Treatment of malignant pheochromocytoma with combination chemotherapy.
Authors: Keiser H R , Goldstein D S , Wade J L , Douglas F L , Averbuch S D
Published: August 2012

Three patients with rapidly progressive, disseminated malignant pheochromocytoma were treated with a combination chemotherapeutic regimen consisting of cyclophosphamide, vincristine, and dacarbazine in repeated 21- to 28-day cycles. All three patients had a marked decrease in blood pressure and an improvement in performance status within the first few cycles of treatment. At a follow-up of 6 to 13 months all patients continue to receive chemotherapy with further regression of tumor in two and stable disease in one. Their blood pressure is normal with minimal or no antiadrenergic therapy. Therapy has been well tolerated; moderate reversible granulocytopenia, neurotoxicity, and one episode of pneumonitis have been the major toxicities encountered. Thus, combination chemotherapy appears to be effective for symptomatic malignant pheochromocytoma.
Comparison of renin and converting enzyme inhibition in sodium-deficient dogs.
Authors: Blaine E H , Nelson B J , Seymour A A , Schorn T W , Sweet C S , Slater E E , Nussberger J , Boger J
Published: August 2012

While renin is a highly specific protease, converting enzyme has at least two principal substrates, angiotensin I and bradykinin. Changes in the rate of formation of angiotensin II or degradation of bradykinin can influence the hypotensive action of angiotensin converting enzyme inhibitors. The present study was designed to determine if there were differences in the maximal blood pressure reduction in Na-deficient dogs after angiotensin converting enzyme or renin inhibitor treatment. Five conscious dogs received 0.1, 0.5, and 1.0 mg/kg of i.v. enalaprilat, a potent angiotensin converting enzyme inhibitor, which reduced blood pressure to 75 +/- 4, 71 +/- 5, and 71 +/- 5 mm Hg. Plasma immunoreactive angiotensin II levels were reduced in a dose-related fashion to 35% of control level at the highest dose. Infusion of a maximally effective dose of a statine-containing renin inhibitor (SCRIP) with the high dose of enalaprilat produced no further fall in blood pressure (68 +/- 7 mm Hg), but immunoreactive angiotensin II levels fell to essentially zero in four of five dogs. The order of drug administration was reversed in another experiment in a group of nine dogs in which SCRIP reduced plasma immunoreactive angiotensin II to 25% of control at 0.04 mg/kg/minute (n = 5), with reduction to near zero levels at higher doses. Maximal blood pressure reduction was achieved at 0.32 to 0.64 mg/kg/minute (76 +/- 4 mm Hg); 1 mg/kg of enalaprilat lowered blood pressure an additional 11 +/- 2 mm Hg (p less than 0.01) while not further decreasing immunoreactive angiotensin II levels.(ABSTRACT TRUNCATED AT 250 WORDS)
Intrarenal adenosine produces hypertension via renal nerves in the one-kidney, one clip rat.
Authors: Katholi R E , McCann W P , Woods W T
Published: August 2012

The afferent renal nerves enhance sympathetic activity in the one-kidney, one-clip hypertensive rat. We have also found adenosine-sensitive nerve endings in the renal pelvis that, when stimulated, increase sympathetic activity producing hypertension. To determine whether adenosine, which is excreted when renal blood flow is reduced, activates the afferent renal nerves in one-kidney, one-clip hypertension, urinary adenosine concentration was lowered by infusing adenosine deaminase into the renal artery. Urinary adenosine concentration was threefold greater in one-kidney, one-clip hypertensive animals compared with normotensive controls. Intrarenal infusion of adenosine deaminase in one-kidney, one-clip rats lowered urinary adenosine to an undetectable level and attenuated the hypertension. Both plasma norepinephrine levels and the fall in mean arterial pressure after ganglionic blockade decreased during intrarenal adenosine deaminase infusion in one-kidney, one-clip animals. Renal denervation in one-kidney, one-clip animals prevented the changes in mean arterial pressure and plasma norepinephrine levels during intrarenal adenosine deaminase infusion. In contrast to findings in hypertensive animals, intrarenal infusion of adenosine deaminase produced no change in arterial pressure in normotensive controls. These data indicate that urinary adenosine concentration is enhanced in one-kidney, one-clip hypertension and suggest that when urinary adenosine concentration is lowered, sympathetic activity and hypertension became attenuated in this model if the renal nerves are intact.
Endothelium-derived vascular relaxing factor.
Authors: Peach M J , Loeb A L , Singer H A , Saye J
Published: August 2012

A large number and variety of compounds (acetylcholine, adenosine diphosphate, adenosine triphosphate, arachidonic acid, bradykinin, Ca2+ ionophores, calcitonin gene-related peptide, histamine, hydralazine, substance P, thrombin, and vasoactive intestinal polypeptide) have been shown to relax arterial smooth muscle indirectly. The endothelium in muscular arteries from several species appears to have receptors for these vasodilators. Binding of one of these compounds to its endothelial receptors results in the release (and presumably synthesis) of substance(s) that act on arterial smooth muscle to cause relaxation. The name endothelium-derived relaxing factor (EDRF) has been proposed for the substance or substances responsible for inhibition of contraction. Studies to determine additivity of endothelium-dependent relaxing agents and sensitivity of EDRF-mediated responses to a variety of inhibitors suggest that a single factor or a single common mechanism induces relaxation of vascular smooth muscle. Pharmacological studies have been equivocal with regard to the postulated involvement of phospholipases or arachidonic acid and to the suggestion that EDRF is an oxidative, non-cyclooxygenase product of arachidonate. Experiments on transfer of EDRF and reversal of endothelium-dependent relaxation consistently indicate that EDRF is quite labile. There is convincing evidence that EDRF activates smooth muscle guanylate cyclase, which results in an increase in intracellular cyclic guanosine 3',5'-monophosphate levels. The stimulation of guanylate cyclase by EDRF provides a valuable and sensitive parameter for studies with arteries as well as cells in culture. At present, the identity of EDRF and its role in cardiovascular homeostasis are unknown.
Clinical and Procedural Predictors of Suboptimal Outcome After the Treatment of Drug-Eluting Stent Restenosis in the Unprotected Distal Left Main Stem
Authors: Takagi Kensuke , Ielasi Alfonso , Shannon Joanne , Latib Azeem , Godino Cosmo , Davidavicius Giedrius , Mussardo Marco , Ferrarello Santo , Figini Filippo , Carlino Mauro , Montorfano Matteo , Chieffo Alaide , Nakamura Sunao , Colombo Antonio
Published: August 2012

Background—

Few data are available regarding the optimal revascularization strategy for unprotected distal left main coronary artery (UDLM) in-stent restenosis (ISR).

Methods and Results—

Between April 2002 and December 2008, UDLM-ISR following drug-eluting stent (DES) implantation occurred in 92 of 474 patients (19.4%). Of these, 8 (8.7%) who underwent a coronary artery bypass graft (CABG) were excluded, and the remaining 84 (91.3%) who underwent percutaneous coronary intervention (PCI) (43 plain old balloon angioplasty [POBA] and 41 DES) were analyzed to assess the feasibility of PCI for UDLM-ISR. The overall cardiac death, myocardial infarction (MI), and major adverse cardiac events during the follow-up period (median, 24 months) occurred in 4, 2, and 31 patients, respectively. Repeat target lesion revascularization (TLR) occurred in 28 patients. The incidence of repeat TLR was higher following PCI with POBA than with DES (hazard ratio [HR], 2.79; 95% CI, 1.23–6.34;
P
=0.014). On Cox regression analysis, the independent predictors of repeat TLR were treatment with POBA (HR, 3.29; 95% CI, 1.41–7.69;
P
=0.006) and EuroSCORE (European System for Cardiac Operative Risk Evaluation) >6 (HR, 2.53; 95% CI, 1.02–6.28;
P
=0.045). More complex lesions requiring a 2-stent strategy were associated with a higher occurrence of TLR for restenosis of the left circumflex coronary artery ostium (LCX-ISR) (HR, 2.51; 95% CI, 1.59–3.97;
P
=0.001) as well as repeat TLR for recurrent LCX-ISR (HR, 4.32; 95% CI, 0.97–19.20;
P
=0.05) compared to a 1-stent strategy. No cardiac death at 2 years occurred in patients with LCX-ISR.

Conclusions—

UDLM restenosis is better treated with DES than with POBA. The rate of recurrent ISR following repeat PCI was high, whereas the rates of MI and death were relatively low. Complex lesions requiring a 2-stent strategy had a higher recurrence rate at the ostial LCX but without an associated increased risk of MI and death.
The Intrinsic Foundations of Extrinsic Motivations and Goals
Authors: Cooper Mick
Published: August 2012

A key contribution of both classical and contemporary humanistic theories is their distinction between intrinsic and extrinsic motivations and drives and their demonstration that psychological well-being is more strongly associated with the former than the latter. However, such a dimensionalization raises the question of how extrinsic motivations and goals emerge; and classic humanistic attempts to account for this tend to contradict some of the basic tenets of humanistic thinking: that human beings are integrated, meaning-seeking agencies consistently striving to maintain and enhance their being. An alternative framework is therefore proposed, a hierarchy of wants, in which extrinsic motivations and goals are seen as attempts—albeit often unsuccessful ones—to reach the highest order, most intrinsic goals. Here, “extrinsic” motivations and goals are not considered pathogenic, per se, but problematic because of their indirectness and lack of fit to present contexts. This model also suggests that human beings are most likely to achieve a state of well-being when their goals are synergetically related: determined both by the internal configuration of goals and external resources.
Global Urban Frontiers through Policy Transfer? Unpacking Seoul’s Creative City Programmes
Authors: Lee Yong-Sook , Hwang Eun-Jung
Published: August 2012

This paper critically examines the Seoul city government’s attempts at the policy transfer of creative cities programmes, both as a policy borrower and as a policy lender, by using the emergent ‘policy mobilities’ approach. Seoul’s way of actualising the idea of creative cities places more emphasis on local-serving administration, tourism and physical cultural infrastructure. The original creative city programmes have been transformed, ideologically and materially, by Seoul into a process of downsizing government organisations and workforce and limiting the use of public space. Seoul’s attempt to be a policy lender is not a product of other foreign cities’ policy transfer from Seoul, but the result of the city government’s promotional practices. Its final outcome, thus bears relatively little relationship or similarity to the original policies, encountering unexpected administrative and operational problems, such as increasing debt and resistance from civil groups.
Marcion and the Resurrection: Some Thoughts on a Recent Book
Authors: Carleton Paget James
Published: July 2012

In a recent book, it has been argued, amongst other things, that Marcion lies behind an apparent rise of interest in the resurrection in the middle of the second century as well as the writing of the canonical Gospels. This review article examines both the way the case is argued and the evidence brought forward to support it.
A review of remote sensing based productivity models and their suitability for studying oil palm productivity in tropical regions
Authors: Tan Kian Pang , Kanniah Kasturi Devi , Cracknell Arthur Philip
Published: August 2012

Oil palm ( Elaeis guineensis Jacq.) cultivation has been expanding and has become one of the fastest developing agricultural crops in tropical regions. Therefore, it is critical to understand the carbon balance and dynamics within oil palm estates to determine its role in the global carbon cycle. Estimating oil palm productivity on a large scale is most feasible with remote sensing based models. Thus, the objective of this paper is to review existing remote sensing based models (i.e. CASA, GLO-PEM, VPM, C-Fix, TURC, EC-LUE, VI, TG, 3-PGS and MOD17) that use light use efficiency (LUE) logic, and subsequently to evaluate the suitability of these models for estimating oil palm productivity. This paper also highlights the limitation of current remote sensing based models for estimating oil palm productivity. From the review of existing literature, it is clear that the existing remote sensing based models need to be modified in terms of meteorological inputs, maximum LUE and environmental constraints in order to improve the estimation of oil palm productivity.
E-waste: a problem or an opportunity? Review of issues, challenges and solutions in Asian countries
Authors: Herat Sunil , Agamuthu P
Published: July 2012

Safe management of electronic and electrical waste (e-waste/WEEE) is becoming a major problem for many countries around the world. In particular, developing countries face a number of issues with the generation, transboundary movement and management of e-waste. It is estimated that the world generates around 20–50 million tonnes of e-waste annually, most of it from Asian countries. Improper handling of e-waste can cause harm to the environment and human health because of its toxic components. Several countries around the world are now struggling to deal with this emerging threat. Although the current emphasis is on end-of-life management of e-waste activities, such as reuse, servicing, remanufacturing, recycling and disposal, upstream reduction of e-waste generation through green design and cleaner production is gaining much attention. Environmentally sound management (ESM) of e-waste in developing countries is absent or very limited. Transboundary movement of e-waste is a major issue throughout the region. Dealing with the informal recycling sector is a complex social and environmental issue. There are significant numbers of such challenges faced by these countries in achieving ESM of e-waste. This article aims to present a review of challenges and issues faced by Asian countries in managing their e-waste in a sustainable way.
Adult Emergence Rhythm of Fruit Flies Drosophila melanogaster under Seminatural Conditions
Authors: De Joydeep , Varma Vishwanath , Sharma Vijay Kumar
Published: August 2012

In insects, the role of circadian clocks in the temporal regulation of adult emergence rhythm under natural conditions has not previously been reported. Here we present the results of a study aimed at examining the time course and waveform of emergence rhythm in the fruit fly Drosophila melanogaster under seminatural condition (SN). We studied this rhythm in wild-type and clock mutant flies under SN in parallel with laboratory condition (LAB) to examine (1) how the rhythm differs between SN and LAB, (2) what roles the circadian clock protein PERIOD and the circadian photoreceptor CRYPTOCHROME (CRY) play in the regulation of emergence rhythm under SN, and (3) whether there is seasonality in the rhythm. Under SN, wild-type flies displayed tightly gated emergence, peaking at “dawn” and gradually tapering down toward the evening, with little or no emergence by night, while in LAB, flies emerged throughout the light phase of light-dark (LD) cycles. The period loss-of-function mutant ( per 0) flies were arrhythmic in LAB but displayed weak rhythmic emergence under SN. Under SN, cry mutants displayed less robust rhythm with wider gates, greater variance in peak timing, and enhanced nighttime emergence compared to controls. Furthermore, flies showed seasonal variation in emergence rhythm, coupled either to light or to humidity/temperature depending on the severity of environmental conditions. These results suggest that adult emergence rhythm of Drosophila is more robust in nature, is coupled to environmental cycles, and shows seasonal variations.
Holistic Wellness Assessment for Young Adults
Authors: Brown Charlene , Applegate Brooks
Published: July 2012

Purpose: The purpose of this study was to develop the Holistic Wellness Assessment (HWA) that incorporates conventional dimensions of wellness with a new dimension of wellness influencing young adults: financial wellness that is psychometrically sound and developmentally appropriate. Design of the study: The study design to establish the initial psychometrics of the HWA was the single-group design. The cross-sectional nature of this design allowed for the postclassification of the participants into different demographic groups facilitating comparisons of the instrument’s derived subscales. Method: From 5,075 university students, 2,090 participants completed an online 285-item HWA and 2,086 respondents provided demographic information. Results: Exploratory factor analysis of the HWA revealed eight dimensions: Self-Regard, Self-Awareness and Responsibility, Sustainability, Relational, Risk Prevention, Spirituality, Physical Health, and Health Care Maintenance. Findings: Four of the eight factors were consistent with existing models of wellness. Three new dimensions of wellness— Self-Regard, Self-Awareness and Responsibility, and Sustainability—emerged from the comprehensive item set that included financial wellness and will set the stage for the development and expansion of wellness models and theories. Conclusion: Initial psychometric analysis suggests that this instrument may prove useful in the young adult population for measuring wellness awareness curriculum and behavior change outcomes.
Funds of knowledge in child-headed households: A Ugandan case study
Authors: Kendrick Maureen , Kakuru Doris
Published: August 2012

Much of the research on orphan and vulnerable children in sub-Saharan Africa has focused on their risks and vulnerabilities. This article describes the ‘funds of knowledge’ (Moll and Greenberg, 1990) and means of acquiring new knowledge of children living in child-headed households in Uganda’s Rakai District. Using ethnographic methods, the authors documented the experiences and activities of children in five rural home contexts. They advance the view of children as resourceful, competent, and knowledgeable, highlighting their ability to build on, utilize, and acquire new funds of knowledge while simultaneously recognizing their conditions of extreme adversity. The authors’ aim is to expand and strengthen the current knowledge base on children living in child-headed households by providing a more nuanced understanding of the relationship between children’s risks and capabilities.
The influence of track irregularities on the running behavior of high-speed trains
Authors: Choi I I-Yoon , Um Ju-Hwan , Lee Jun S , Choi Hyun-Ho
Published: August 2012

Irregularities in railway tracks influence the running behavior of trains; large irregularities can result in poor ride comfort and in some cases derailment. Thus, it is important that the relationship between track irregularities and the running behavior of trains is identified and criteria for track irregularities are adequately established. However, the questions of how track irregularities affect the vehicle responses that determine running safety and ride comfort and how the wavelength and amplitude of each track irregularity influence the vehicle responses are barely addressed in the literature. This paper reports the results of computer simulation studies that were performed to investigate the influence of the longitudinal level, alignment and cross level of track irregularities on the running behavior of the 300 km/h KTX (Korea Train Express) train. A straight track was assumed in the calculations to ensure a focus on the effect of track irregularities. Track irregularities with various wavelengths and amplitudes were modeled using the VAMPIRE program; a vehicle dynamics modeling package that is widely utilized to study railway environments. Simulations on the effects of derailment coefficients, lateral loads, bogie acceleration and body acceleration created by track irregularities were performed to evaluate how the track irregularities affect the safety and ride comfort of the KTX. The results of the simulations indicate that track alignment has a significant impact on running safety whereas longitudinal level does not have any significant impacts.
Numerical study of the effect of effective diffusivity and permeability of the gas diffusion layer on fuel cell performance
Authors: Hossain Mamdud , Islam Sheikh Zahidul , Pollard Patricia
Published: August 2012

A three-dimensional, single-phase, isothermal, explicit electrochemistry polymer electrolyte membrane fuel cell model has been developed and the developed computational model has been used to compare various effective diffusivity models of the gas diffusion layer. The Bruggeman model has traditionally been used to represent the diffusion of species in the porous gas diffusion layer. In this study, the Bruggeman model has been compared against models based on particle porous media, multi-length scale particles and the percolation-type correlation. The effects of isotropic and anisotropic permeability on flow dynamics and fuel cell performance have also been investigated. This study shows that the modelling of the effective diffusivity has significant effects on the fuel cell performance prediction. The percolation-based anisotropic model provides better accuracy for the fuel cell performance prediction. The effects of permeability have been found to be negligible and the specification of any realistic value for permeability has been found to be sufficient for polymer electrolyte membrane fuel cell modelling.
A numerical study of blade thickness and camber effects on vertical axis wind turbines
Authors: Danao Louis Angelo , Qin Ning , Howell Robert
Published: August 2012

This article presents the results of a two-dimensional computational study into the effects of rotor blade thickness and camber on the performance of a 5 kW scale vertical axis wind turbine. Validation is provided by reference to experimental data for a pitching aerofoil with dynamic stall phenomenon. The performance of the turbine is mapped out for a variety of different tip speed ratios and detailed investigations are presented to determine how and, most importantly, why the turbine performance varies with thickness and camber as it does. The rotor blades chosen were the NACA0012, NACA0022, NACA5522 and LS0421. The turbine rotor has a diameter of d = 3.1 m with a blade chord length of c = 0.18 m. Over the range of tip speed ratios examined, the NACA0012 profile performed with the highest overall performance of 50% at λ = 3.5. Slightly cambered aerofoils (such as the LS0421) can improve the overall performance of the vertical axis wind turbine, whereas a camber of 5% (NACA5522) results in unfavourable performance. Of the cambered blades tested, the LS0421 performs the best with maximum CP of 0.40 at λ = 3.5. A camber along the blade path causes the blades to generate higher values of torque in both the upwind and the downwind regions. It was also determined that inverted cambered profiles produce power mostly in the upwind region.
Development of Quality Index Method for anchovy (Engraulis anchoita) stored in ice: Assessment of its shelf-life by chemical and sensory methods
Authors: Massa AE , Manca E , Yeannes MI
Published: August 2012

The objective of this study was to develop a quality index method for Engraulis anchoita stored in ice and to determine its shelf-life based on this quality index method and chemical indices such as total volatile bases and thiobarbituric acid-reactive substances. Besides, the chemical composition with emphasis on the polyunsaturated fatty acids content was determined. The results indicate that E. anchoita is a valuable protein source and lipid with important content of n-3 polyunsaturated fatty acids. The developed quality index method scheme was composed of 28 demerit points, divided into 4 parameters and 10 attributes. All attributes showed correlation with time of storage ( R > 0.90). The quality index (QI) presented a linear relationship with storage (QI = 2.55 x days in ice + 1.76; R2 = 0.98). In the shelf-life assessment-based quality index method, the rejection sensory point was observed after 7 days of storage due to the presence of unpleasant odours and deteriorated appearance. The total volatile basic nitrogen value remained below the upper limit of acceptability during the 10 days of ice storage. The evolution of thiobarbituric acid-reactive substances indicates lipids oxidation during the storage of anchovies. According to the results, the quality index method scheme developed for the E. anchoita stored in ice could be considered adequate to evaluate their freshness and to estimate its shelf-life.