bluuebunny/crossref_metadata_2025 huggingface dataset:
Effectiveness of atenolol in the treatment of hypertension during pregnancy.
Authors: Fabregues G , Alvarez L , Varas Juri P , Drisaldi S , Cerrato C , Moschettoni C , Pituelo D , Baglivo H P , Esper R J
Published: August 2012

This study assessed the effectiveness of atenolol in the treatment of moderate and severe hypertension during pregnancy. Seventy patients (mean age, 30.3 +/- 6.0 years), 35.7% primiparous, were included. Three groups were formed according to Davey and MacGillivray's classification: 1) chronic hypertension without proteinuria (12 patients), 2) gestational hypertension without proteinuria (52 patients), and 3) preeclampsia (six patients). Treatment with atenolol was started when blood pressure was 150/100 mm Hg or higher after 48 hours' rest. The treatment lasted at least 1 week; follow-up was every 2 weeks up to week 36, and from then on, weekly up to delivery. If blood pressure exceeded 160/110 mm Hg and the fetus was not yet mature, a second drug was added. A significant decrease in blood pressure was observed in the three groups (group 1: 155.8 +/- 15.0/100.8 +/- 7.6 versus 135.0 +/- 12.9/85.0 +/- 6.7 mm Hg; group 2: 154.2 +/- 13.6/104.9 +/- 9.3 versus 129.6 +/- 10.2/83.7 +/- 9.1 mm Hg; group 3: 158.3 +/- 27.1/104.1 +/- 8.0 versus 129.1 +/- 6.6/87.5 +/- 6.1 mm Hg). The doses of atenolol were 62.5 +/- 23.0 mg/day in group 1, 70.0 +/- 30.0 mg/day in group 2, and 100.0 +/- 41.0 mg/day in group 3. There was no fetal mortality. No significant difference occurred in newborn body weights. Four babies from group 2 mothers had an Apgar score of less than 7 at 1 minute, but only one remained abnormal after 5 minutes. In the same group, three cases of respiratory distress were observed.(ABSTRACT TRUNCATED AT 250 WORDS)
Expression of alpha-smooth muscle actin in the developing kidney vasculature.
Authors: Carey A V , Carey R M , Gomez R A
Published: August 2012

To determine whether alpha-smooth muscle (alpha-SM) isoactin is expressed in the maturing kidney as well as the changes associated with maturation, we processed for immunocytochemistry kidney sections from Wistar-Kyoto rats at various prenatal (15, 17, 19, and 20 days) and postnatal (2, 5, 10, 15, and 90 days) ages using a monoclonal anti-alpha-SM actin antibody. At 15 days of gestation, only a few mesenchymal cells contained alpha-SM actin. However, other fetal vasculature structures (heart, aorta, peripheral blood vessels) expressed alpha-SM actin. Vascular localization was first observed at 17 days of gestation in larger corticomedullary vessels. As maturation progressed, actin expression accompanied the outward growth and branching of the kidney vasculature. During fetal life (17 days), alpha-SM actin also was expressed within juxtamedullary glomeruli. As the centrifugal maturation of nephrons proceeded, intraglomerular expression extended to outer cortical glomeruli. After 10 days of postnatal life, once glomerular development was completed, intraglomerular expression was no longer present. Peritubular capillaries expressed alpha-SM actin during early (fetal and neonatal) development, but not in the adult kidney. We conclude that 1) expression of alpha-SM actin in the developing kidney is delayed with respect to other vascular beds, 2) expression of alpha-SM actin follows the centrifugal pattern of nephrovascular development, and 3) glomerular and peritubular capillary expression of alpha-SM actin is a transient developmental phenomenon associated with active glomerulogenesis and capillary growth.
Centrally infused bradykinin increases baroreceptor reflex sensitivity.
Authors: Gerken V M , Santos R A
Published: August 2012

Kinins are present in the central nervous system, and central administration of bradykinin increases blood pressure and heart rate. In this study, we determined the effect of intracerebroventricular infusion of bradykinin on the baroreceptor reflex of conscious rats. Male Wistar rats were anesthetized with thiobarbital (40 mg/kg i.p.), and chronic intracerebroventricular cannulas (25 gauge) were implanted into the lateral ventricles. Baroreceptor control of heart rate was evaluated by recording reflex heart rate changes (beats per minute) in response to mean arterial pressure changes (mm Hg) produced by bolus injection of phenylephrine (0.5-20 micrograms/kg i.v.) or sodium nitroprusside (0.5-25 micrograms/kg i.v.). The ratio beats per minute/mm Hg or the mean slope of the individual regression lines of the relation between heart rate and mean arterial pressure changes for increases or decreases in arterial pressure was used as an index of baroreceptor reflex sensitivity. Baroreceptor control of heart rate was evaluated within 1 and 3 hours of intracerebroventricular infusion of bradykinin (7.5 micrograms/7 microliters/hr) or saline (7 microliters/hr). There was no change in basal mean arterial pressure or heart rate during central bradykinin infusion (112 +/- 2 mm Hg and 402 +/- 18 beats per minute in the control period). After 1 hour of central bradykinin infusion, there was a significant increase of baroreceptor reflex sensitivity for increments in mean arterial pressure (-2.91 +/- 0.26 versus -1.5 +/- 0.24 beats per minute/mm Hg in the control period; p less than 0.01, paired Student's t test). In contrast, no significant changes were observed for the reflex tachycardia. Similar results were obtained with 3 hours of infusion.(ABSTRACT TRUNCATED AT 250 WORDS)
Rapid eye movement sleep deprivation and hypertension. Genetic influence.
Authors: Neves F A , Marson O , Baumgratz R P , Bossolan D , Ginosa M , Ribeiro A B , Kohlmann O , Ramos O L
Published: August 2012

We studied the importance of genetic predisposition in the development of stress-induced hypertension in the spontaneously hypertensive rat (SHR), Wistar-Kyoto (WKY) rat, and borderline hypertensive rat (BHR; first-generation offspring of SHR and WKY). Rats were submitted to seven 72-hour sessions of rapid eye movement sleep deprivation (REM-sd) every other week during 13 weeks. Tail arterial pressure was determined throughout the experiment. At the end of the study, mean arterial pressure (direct measurement), sympathetic activity (acute blockade with propranolol and phentolamine), and ventricular weight were determined. Results showed that REM-sd induced sustained hypertension only in rats with a partial predisposition to developing hypertension (BHRs). Values of tail arterial pressure at the end of the study were BHR REM-sd, 175 +/- 1.6 mm Hg and control BHR, 155.9 +/- 0.9 mm Hg, p less than 0.05; SHR REM-sd, 219 +/- 2.6 mm Hg and control SHR, 211.9 +/- 3.4 mm Hg, NS; WKY REM-sd, 123.9 +/- 2 mm Hg and control WKY, 125.4 +/- 2.2 mm Hg, NS. Stressed groups showed higher reduction of mean arterial pressure than their controls when submitted to sympathetic blockade (SHR REM-sd, -75.7 +/- 13.2 mm Hg and control SHR, -60 +/- 4.5 mm Hg, p less than 0.05; BHR REM-sd, -38.4 +/- 3.6 mm Hg and control BHR, -24.3 +/- 2.1 mm Hg, NS; WKY REM-sd, -34.4 +/- 2.5 mm Hg and control WKY, -25.6 +/- 3.3 mm Hg, NS). REM-sd increased ventricular weight in all strains. These increments showed no correlation with blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)
Hypokalemia, glucose intolerance, and hyperinsulinemia during diuretic therapy.
Authors: Plavinik F L , Rodrigues C I , Zanella M T , Ribeiro A B
Published: August 2012

Hypokalemia and glucose intolerance may result from diuretic therapy. Increases in plasma insulin and glucose levels have been observed in thiazide-treated hypertensive patients and have been attributed to a diminished insulin sensitivity induced by diuretic therapy. To investigate the effects of hypokalemia on glucose tolerance and insulin secretion, we studied 21 essential and nine diabetic hypertensive patients after 4 weeks of placebo and after 4 weeks of chlorthalidone therapy (25 mg/day). Plasma glucose and insulin levels were measured for a 3-hour period after a 75-g glucose oral dose. Hypokalemia developed in seven of the essential hypertensive patients (HK group), whereas only one diabetic patient had decreased plasma potassium levels to below 3.5 meq/l. The results obtained in the HK group after chlorthalidone showed that plasma glucose and insulin values increased after the oral glucose load to levels significantly higher than those observed after placebo. In contrast, the patient who remained normokalemic after chlorthalidone did not show any change in plasma insulin and glucose levels during glucose tolerance testing. These results show that diuretic therapy may induce hyperglycemia and hyperinsulinemia and suggest that potassium depletion is involved in the increase in insulin resistance that has been demonstrated during thiazide therapy.
Production of angiotensin-(1-7) by human vascular endothelium.
Authors: Santos R A , Brosnihan K B , Jacobsen D W , DiCorleto P E , Ferrario C M
Published: August 2012

The heptapeptide angiotensin-(1-7) is a circulating biologically active product of the renin-angiotensin system. In this study, we evaluated the role of the vascular endothelium in the formation of angiotensin-(1-7). Metabolism of 125I-angiotensin I was investigated using confluent cultured bovine and human aortic and umbilical vein endothelial cells. The fetal calf serum-supplemented medium was replaced by serum-free medium containing 0.2% bovine serum albumin. One hour later, this medium was replaced by serum-free medium containing 125I-angiotensin I. After incubation of 125I-angiotensin I for various intervals at 37 degrees C, the medium was collected and analyzed for formed products by high-performance liquid chromatography. Products of angiotensin I metabolism were identified by comparison of their retention times with those of radiolabeled standards. The contribution of proteases released into the medium was evaluated by incubation of 125I-angiotensin I with medium previously incubated for 1 hour with endothelial cells. Incubation of 125I-angiotensin I with bovine and human endothelial cells produced a time-dependent generation of 125I-angiotensin-(1-7) greater than 125I-angiotensin II greater than 125I-angiotensin-(1-4). Generation of angiotensin peptides was not due to the presence of proteases in the medium. When human umbilical endothelial cells were incubated in the presence of the angiotensin converting enzyme inhibitor enalaprilat (1 microM), generation of angiotensin II was undetectable. In contrast, angiotensin-(1-7) production increased by an average of 30%.(ABSTRACT TRUNCATED AT 250 WORDS)
Systolic blood pressure differences among pediatric epidemiological studies.
Authors: Fixler D E , Kautz J A , Dana K
Published: August 2012

This report reviews the results of six large blood pressuree surveys done on pediatric populations and points out factors responsible for differences in the blood pressure norms. The studies were selected on the basis of there being recent examinations of large numbers of children. Important differences in mean systolic pressures and 95th percentile values were found among the studies, which may be attributed to: 1) actual differences among the populations; 2) biases due to methodological differences; or 3) increased sampling variability with small sample sizes. Actual differences in pressures among the populations surveyed may be due to differences in geographic location, racial composition, or average body sizes. Discrepancies due to methodological biases may have occurred because of associated venipuncture or exercise stress on the day of the examination; differences in selection of blood pressure cuff sizes; differences in the number of measurements averaged. In several studies, small sample sizes for each age-race-sex subclass accounted for considerable variability of the 95th percentile value. The implication of this analysis is that before the 95th percentile norms for children of different ages, races, and sexes can be more firmly established, it is necessary to collect larger sample sizes controlling for known biasing factors and using a standardized methodology.
Role of the lipoxygenase pathway in angiotensin II-induced vascular smooth muscle cell hypertrophy.
Authors: Natarajan R , Gonzales N , Lanting L , Nadler J
Published: August 2012

The 12-lipoxygenase pathway is a key mediator of angiotensin II (Ang II)-induced effects in the adrenal cortex. We also recently demonstrated that Ang II increases 12- and 15-lipoxygenase product levels in vascular smooth muscle cells. However, the relation between lipoxygenase activation and Ang II-induced vascular smooth muscle cell hypertrophy is not known. We studied the effects of Ang II and 12-lipoxygenase products on both total cell protein content and the levels of the matrix protein fibronectin in quiescent porcine aortic smooth muscle cells. Ang II-induced increases in cellular protein content were attenuated by the specific 12-lipoxygenase inhibitor baicalein; in contrast, the cyclooxygenase inhibitor ibuprofen had no effect. Direct addition of the 12-lipoxygenase product 12-S-hydroxyeicosatetraenoic acid increased total cell protein content. We have recently shown that porcine vascular smooth muscle cell growth is potentiated in high glucose (25 mmol/L) culture conditions. We observed that both Ang II and 12-S-hydroxyeicosatetraenoic acid induced a greater increase in protein content in cells cultured for two passages in high glucose. Furthermore, Ang II and 12-S-hydroxyeicosatetraenoic acid also markedly increased fibronectin levels in cells cultured in high glucose. These results suggest that 12-lipoxygenase activation plays a key role in Ang II-induced vascular smooth muscle cell hypertrophy. Furthermore, both Ang II and lipoxygenase effects are enhanced in cells cultured under hyperglycemic conditions.
Pressor mechanisms in adriamycin-induced nephropathy with hypertension in rats.
Authors: Franco R , Gut A , Ferrari-Spadotto A , Georgette J , Gavras I , Gavras H
Published: August 2012

We explored the role of angiotensin II and vasopressin in the maintenance of blood pressure during the nephrotic syndrome of adriamycin-induced nephropathy in rats. All 91 rats treated with adriamycin developed chronic renal failure with nephrotic syndrome, which was more pronounced in the normotensive rats than the 35% who became hypertensive. Angiotensin II blockade with DuP 753 produced a significantly greater hypotensive response in both the adriamycin-hypertensive (-16 +/- 3 mm Hg) and adriamycin-normotensive (-14 +/- 5 mm Hg) groups than the saline-treated controls (-5 +/- 1 mm Hg, P < .05). Vasopressin blockade with either a V1V2 inhibitor or a selective V1 inhibitor produced a hypotensive response in adriamycin-hypertensive rats only (by -16 +/- 4 and -17 +/- 2 mm Hg, respectively, P < .01), although the nonselective vasopressin inhibitor produced similar fluid loss and body weight reduction in all three groups. The data suggest that in adriamycin-induced nephropathy with nephrotic syndrome, angiotensin II contributes to blood pressure maintenance in both hypertensive and normotensive animals, whereas the pressor action of vasopressin contributes to elevated blood pressure in hypertensive animals only.
Regression of left ventricular hypertrophy in two-kidney, one clip Goldblatt hypertension.
Authors: Kuwajima I , Kardon M B , Pegram B L , Sesoko S , Frohlich E D
Published: August 2012

The effect of regression of left ventricular hypertrophy (LVH) on ventricular performance was studied in two-kidney, one clip Goldblatt hypertensive rats (2K1C) treated with methyldopa or by unclipping. Sham operations were performed in a total of 21 rats; 12 and nine were studied after 4 and 6 weeks, respectively. Hypertension was induced in 38 additional rats. Of these, 11 were studied at 4 weeks. Cardiac index was measured by electromagnetic flowmetry under light ether anesthesia, and ventricular performance was assessed by rapid intravenous saline infusion. Of the remaining 27 hypertensive rats at 4 weeks postclipping, 10 were treated with methyldopa (400 mg/kg/day) and nine were unclipped; eight were left untreated as controls. Two weeks thereafter, ventricular performance was determined as described above. When expressed as the relationship between cardiac index and LV end-diastolic pressure, ventricular performance tended to be depressed in 2K1C. Ventricular performance, mean arterial pressure, and LV-to-body weight ratio returned to control in unclipped rats. Whereas methyldopa resulted in regressed LVH, its effect on mean arterial pressure and total peripheral resistance was not as marked as unclipping, both remaining significantly increased (p less than 0.001). The disparate effects of unclipping and methyldopa on systemic hemodynamics indicate that the improved ventricular performance with methyldopa was related more to its effect on LVH, suggesting that in these animals regression of LVH was associated with improved ventricular performance.
Calcium- and endothelial-mediated vascular smooth muscle relaxation in rabbit aorta.
Authors: Singer H A , Peach M J
Published: August 2012

The role of calcium in the relaxations evoked by methacholine and A23187 in intact rabbit aortic rings was investigated. Methacholine (10(-8) to 10(-6) M) and the calcium ionophore A23187 (10(-8) to 10(-6) M) produced dose-dependent relaxations of rings which had been contracted with the alpha-adrenergic agonist phenylephrine. The ability of a ring to relax in this manner was correlated with the presence of endothelium as judged by transmission and scanning electron microscopy. Purposely disrupting the endothelium led to a loss of the relaxation response. In these rings methacholine caused dose-dependent contractions at concentrations greater than 10(-7) M. Deletion of Ca++ from the incubation medium inhibited maximum methacholine-induced relaxations by 67% and A23187-induced relaxations by 92%. The Ca++-channel blockers verapamil (10 microM) and nifedipine (0.5 microM) inhibited maximum methacholine-induced relaxations by 39% and 45%, respectively. The blockers had no effect on the methacholine ED50 (2.5 x 10(-7) M) for relaxation. Verapamil and nifedipine also inhibited maximum A23187-induced relaxations by 43% and 47% with no effect on the ED50 (6 x 19(-8) M) for relaxation. A structurally dissimilar vasodilator, sodium nitroprusside (10(-7) M), had no effect on the A23187-induced relaxation. These data are consistent with a role of Ca++ in regulating either the production or release of endothelial-derived relaxing factor(s).
Evidence that disruption of the blood-brain barrier precedes reduction in cerebral blood flow in hypertensive encephalopathy.
Authors: Tamaki K , Sadoshima S , Baumbach G L , Iadecola C , Reis D J , Heistad D D
Published: August 2012

Alternative hypotheses concerning the pathogenesis of hypertensive encephalopathy are that vasospasm produces cerebral ischemia and cerebral edema, or that passive dilation of cerebral vessels during severe hypertension produces disruption of the blood-brain barrier and cerebral edema. Stroke-prone spontaneously hypertensive rats (SHRSP) were studied when they developed signs of neurological dysfunction. We measured regional cerebral blood flow (rCBF) with 14C-iodoantipyrine, and permeability of the blood-brain barrier with Evans blue dye. Twelve rats had focal disruption of the barrier without histological evidence of ischemic infarction or cerebral hemorrhage: areas with disruption of the barrier had severe focal edema in seven rats and minimal edema in five rats. In areas with disruption of the barrier and marked focal edema, rCBF was decreased to 38 +/- 8 (mean +/- SE) ml/min/100 g vs 102 +/- 13 (p less than 0.05) in other areas of the ipsilateral hemisphere, and 86 +/- 16 in the homologous area of the contralateral hemisphere (p less than 0.05). In contrast, in areas with disruption of the blood-brain barrier with only minimal edema, rCBF was normal or increased: rCBF was 100 +/- 11 ml/min/100 g vs 85 +/- 12 in other areas of the ipsilateral hemisphere (p greater than 0.05) and 64 +/- 8 in the homologous area contralaterally (p less than 0.05). The findings indicate that edema precedes reduction in rCBF in SHRSP and suggest that the initiating event in hypertensive encephalopathy is disruption of the blood-brain barrier, and not vasospasm.
Left ventricular function in early primary hypertension. Functional consequences of cardiovascular structural changes.
Authors: Wikstrand J
Published: August 2012

An increase in left ventricular (LV) wall thickness will lead to decreased LV distensibility during both LV passive filling and left atrial contraction. Reduced LV distensibility will change the filling pattern of the left ventricle, and a proportionally smaller part of the stroke volume will be delivered during the passive filling of the preceding diastole and a larger part during late diastole by a more powerful left atrial contraction. With a more pronounced increase in LV wall thickness a reduced distensibility of venous capacitance vessels (functional or structural) will probably help to preserve LV pump function by influencing LV filling and use of the Frank-Starling mechanism. LV wall stress (peak and end-systolic) is high and LV intrinsic contractility is normal or supernormal in early primary hypertension, as judged from the relationship between end-systolic wall stress and different indices of LV function (fractional shortening, mean velocity of circumferential fiber shortening, ejection fraction). Great differences in peak systolic wall stress may be recorded among groups with comparable values for LV end-systolic wall stress, which may be explained by very different degrees of cardiovascular structural changes, with higher values for peak systolic wall stress seen in hypertension caused by high output than those values seen in hypertension caused by high total peripheral resistance. Signs of supernormal LV systolic function are common in high output hypertension, which is also at least partly due to an increase in LV end-diastolic volume and use of the Frank-Starling mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)
Myocardial cell hypertrophy or hyperplasia.
Authors: Oparil S , Bishop S P , Clubb F J
Published: August 2012

Growth of the vertebrate heart during embryonic and fetal life is characterized by hyperplasia of myocardial cells; these cells increase in number to a value characteristic for each species. Shortly after birth myocardial cells lose the capability of dividing, and further growth of the heart is due to myocardial cell hypertrophy and nonmuscle cell hyperplasia. This process, which is referred to as hypertrophic growth, results in a 30- to 40-fold increase in volume of individual myocardial cells during normal postnatal growth and maturation. The transition from hyperplastic to hypertrophic growth is related to formation of binucleated myocardial cells as a result of karyokinesis without cytokinesis. The molecular mechanism of this transition is uncertain. The response of the heart to increased metabolic demands or to an increased workload depends on the age of the animal at the time the stress is imposed. Increased myocardial workloads due to systemic hypertension, chronic hypoxia, or carbon monoxide exposure in fetal or early neonatal life lead to cardiac enlargement by causing an increased rate of hyperplasia of myocardial cells or continuation of hyperplasia beyond the normal period of hyperplastic growth. In contrast, imposition of increased loads on the hearts of older animals results in cardiac hypertrophy due to enlargement of myocardial cells and hyperplasia of nonmuscular components. In addition to cellular enlargement, structural remodeling of the myocardial cells, including alterations in the relative proportions of cellular organelles and in the ultrastructure of individual organelles, occurs during the development of hypertrophy in the adult heart.(ABSTRACT TRUNCATED AT 250 WORDS)
Effects of hypertension on migration and proliferation of smooth muscle in culture.
Authors: Haudenschild C C , Grunwald J , Chobanian A V
Published: August 2012

Migratory and proliferative characteristics of explanted rat aortic smooth muscle cells were studied in response to hypertension induced by 4 weeks of deoxycorticosterone-salt administration. Under low serum conditions (0.1% fetal bovine serum), over 80% of aortic medial explants from hypertensive rats yielded smooth muscle cell colonies after 8 days of culture while fewer than 10% of the control explants were positive. Time lapse video analysis of subsequent growth in the presence of 10% serum revealed that interdivision times of smooth muscle cells from hypertensive animals were significantly shorter than those in controls (p less than 0.01). Significant differences in proliferative capacity of smooth muscle cells were evident, even after one subculture (p less than 0.01). Comparison of these results with data from mechanical injury suggests that 4 weeks of deoxycorticosterone-salt hypertension can potentiate subsequent smooth muscle cell migration and growth in vitro to an extent similar to that observed with the combined effects of total endothelial denudation and wall distention by a balloon catheter.
Potassium reduces cerebral hemorrhage and death rate in hypertensive rats, even when blood pressure is not lowered.
Authors: Tobian L , Lange J , Ulm K , Wold L , Iwai J
Published: August 2012

In a study of the effects of K+ in stroke prone spontaneously hypertensive rats, adding K+ to normal chow was found to reduce the mortality from 83% to 2%, a 98% reduction. An 86% reduction in mortality occurred even when blood pressure was virtually equal in the two stroke prone spontaneously hypertensive groups being compared. Dietary K+ supplements also reduced mortality in hypertensive Dahl salt-sensitive rats from 55% to 4%, a 93% reduction. There was an 87% reduction in mortality even when blood pressure was equal in the Dahl salt-sensitive groups being compared. The added dietary K+ decreased blood pressure moderately in stroke prone spontaneously hypertensive rats and modestly in Dahl salt-sensitive rats, which probably contributed to the reduced death rate. More importantly, however, the added K+ seemed to prevent severe lesions in cerebral arteries and deaths even when blood pressure lowering was eliminated as a protective factor. In another group of stroke prone spontaneously hypertensive rats, there was a 40% incidence of cerebral hemorrhage in surviving rats not receiving K+ supplements and no incidence of cerebral hemorrhage in similar surviving rats receiving K+ supplements, which suggests that K+ supplements confer protection against brain hemorrhage.
Sympathetic nervous system mediation of acute cardiovascular actions of gamma 2-melanocyte-stimulating hormone.
Authors: Callahan M F , Kirby R F , Wolff D W , Strandhoy J W , Lymangrover J R , Johnson A K , Gruber K A
Published: August 2012

Peptides of the pro-opiocortin class produce pronounced cardiovascular and natriuretic actions. We have investigated the acute cardiovascular effects of one of the most potent members of this class, gamma 2-melanocyte stimulating hormone (gamma 2-MSH), in rats. Pressor actions of gamma 2-MSH administered systemically were eliminated by ganglionic blockade with chlorisondamine. Peripheral cholinergic blockade failed to affect either the pressor or cardioaccelerator responses to gamma 2-MSH. Administration of gamma 2-MSH (2.0-10.0 micrograms) produced vasoconstriction primarily in the mesenteric and hindlimb vascular beds, while the renal bed showed little response. Infusions of phenylephrine produced pressor responses similar to those found with gamma 2-MSH, which were accompanied by a decrease in heart rate and vasoconstriction in the mesenteric and renal vascular beds. Hemodynamic changes produced by gamma 2-MSH and phenylephrine were blocked or attenuated by alpha 1-adrenergic receptor blockade with prazosin. Direct injection of gamma 2-MSH into the renal artery produced an acute renal vasoconstriction that was not attenuated by alpha 1-adrenergic or ganglionic blockade. These findings and the results of previous publications are consistent with the hypothesis that gamma 2-MSH may produce a centrally mediated activation of the sympathetic nervous system, have direct vasoconstriction actions on the renal vasculature, and inhibit baroreceptor function to produce an increase in blood pressure without an accompanying bradycardia.
Clinical and Stent-Related Outcomes After Transcatheter or Operative Placement of Bare-Metal Stents in the Ventricular Septum or Subvalvar Systemic Outflow Tract
Authors: Porras Diego , McElhinney Doff B. , del Nido Pedro , Lock James E. , Meadows Jeffrey , Marshall Audrey C.
Published: August 2012

Background—

Stenting of the systemic ventricular outflow tract and creation or enlargement of a ventricular septal defect using stents are potential therapeutic options in rare patients with congenital heart disease who develop significant ventricular hypertension due to outflow obstruction. These stents may be at increased risk of fracture because of exposure to cyclic compressive stresses. The objective of this study was to evaluate the safety and efficacy of this intervention and to determine the incidence of stent fracture and other adverse outcomes after placement of intraventricular or interventricular stents for this indication.

Methods and Results—

Between 1992 and 2010, 27 patients underwent bare-metal stent placement in the ventricular septum or subvalvar systemic outflow tract, using 1 of the following 3 delivery approaches: (1) percutaneous (n=18), (2) intraoperative (n=8), and (3) hybrid (n=1). The median ventricular-to-aortic systolic pressure ratio decreased from 1.7 (1.3–2.6) to 1.1 (0.9–1.8) (
P
<0.001). Survival free from surgical reintervention for outflow obstruction was 92% at 1 year and 66% at 3 years. Stent fracture was diagnosed in 11 patients (41%) a median of 2.6 years (0.03–7.8 years) after stent placement and was always associated with recurrent obstruction. Survival free from diagnosis of stent fracture was 84% at 1 year and 73% at 3 years. Other adverse events included complete heart block (n=2) and increased atrioventricular valve regurgitation requiring surgical intervention (n=2).

Conclusions—

Transcatheter, intraoperative, or hybrid stenting of the ventricular septum or systemic outflow tract is feasible and effective in the short term. Stent fractures were common during follow-up and associated with recurrent obstruction.
Endothelium-Selective Activation of AMP-Activated Protein Kinase Prevents Diabetes Mellitus–Induced Impairment in Vascular Function and Reendothelialization via Induction of Heme Oxygenase-1 in Mice
Authors: Li Francois Y.L. , Lam Karen S.L. , Tse Hung-Fat , Chen Cheng , Wang Yiqun , Vanhoutte Paul M. , Xu Aimin
Published: August 2012

Background—

Endothelial damage and dysfunction are crucial mediators that link diabetes mellitus with atherosclerotic cardiovascular disease. AMP-activated kinase (AMPK) has been implicated in regulation of both energy metabolism and vascular homeostasis. The present study investigated whether endothelium-selective activation of AMPK prevents diabetes mellitus–induced endothelial damage and vascular dysfunction by improving reendothelialization in mice.

Methods and Results—

Transgenic mice with endothelium-selective expression of a constitutively active (CA) AMPK were generated and rendered diabetic by the injection of streptozotocin. Relaxation and reendothelialization of carotid arteries and circulating numbers of endothelial progenitor cells (EPCs) were examined after wire-induced denudation. Bone marrow–derived EPCs were isolated to monitor their in vivo and in vitro function. Compared with wild-type littermates, the CA-AMPK transgenic mice were resistant to diabetes mellitus–induced impairment in endothelium-dependent relaxation and reendothelialization of their injured carotid arteries. These changes in the transgenic mice were accompanied by increased mobilization of EPCs and enhanced incorporation of EPCs into injured blood vessels. Furthermore, EPCs from the transgenic mice exhibited augmented adhesion, migration, and tube formation capacities. At the molecular level, the expression of heme oxygenase (HO)-1 and the secretion of stromal cell–derived factor (SDF)-1α were upregulated in EPCs derived from the transgenic mice, whereas AMPK-mediated elevation of serum SDF-1α levels and improvements of EPC function and reendothelialization were all abrogated by pharmacological inhibition of heme oxygenase-1.

Conclusions—

Endothelium-specific AMPK activation is sufficient to protect against diabetes mellitus–induced aggravation of vascular injury by promoting EPC function and reendothelialization via upregulation of heme oxygenase-1 and SDF-1α.
Incidence of New Diffusion-Weighted Imaging Lesions Outside the Area of Initial Hypoperfusion Within 1 Week After Acute Ischemic Stroke
Authors: Usnich Tatiana , Albach Fredrik N. , Brunecker Peter , Fiebach Jochen B. , Nolte Christian H.
Published: August 2012

Background and Purpose—

New diffusion-weighted imaging (DWI) lesions are common in patients with acute ischemic stroke. The pathophysiology of these new lesions is unclear. We differentiated new DWI lesions outside the area of initial hypoperfusion from those confined to the area of initial hypoperfusion.

Methods—

Patients with acute stroke underwent 3 MRI examinations: on admission, on the next day, and 4 to 7 days after symptom onset. Patients were included if a perfusion deficit was present on the initial scan. Lesions on DWI images were delineated manually. Coregistered DWI images were analyzed visually for new hyperintensities. In reference to the perfusion maps (mean transit time), patients were classified as having “outside lesions” if new DWI lesions were outside or both outside and inside the area of the initial perfusion deficit or “inside lesions” if new DWI lesions were completely inside.

Results—

We enrolled 164 patients. Thirty-eight patients (23%) had outside lesions and 34 patients (21%) had inside lesions. In multivariable regression analysis, new outside lesions were significantly associated with symptomatic carotid stenosis, multiple index lesions pattern, and high low-density lipoprotein levels. New inside lesions were significantly associated with (spontaneous or thrombolytic) vessel recanalization, multiple index lesions pattern, and low low-density lipoprotein levels.

Conclusion—

Outside and inside lesions represent different pathophysiological entities. More specifically patients with outside lesions may have an increased risk for subsequent cerebrovascular events.
Prevalence and Predictors of 6-Month Fatigue in Patients With Ischemic Stroke
Authors: Feigin Valery L. , Barker-Collo Suzanne , Parag Varsha , Hackett Maree L. , Kerse Ngaire , Barber P. Alan , Theadom Alice , Krishnamurthi Rita
Published: August 2012

Background and Purpose—

Although persistent and significant fatigue affects the daily life of stroke survivors, there are no population-based studies examining the prevalence of fatigue in 6-month survivors of ischemic stroke and few studies of predictors of poststroke fatigue.

Methods—

This article examined data from the Auckland Regional Community Stroke study conducted in Auckland, New Zealand, in 2002 to 2003. Presence of fatigue was evaluated at 6 months in 613 patients with ischemic stroke using a Short Form 36 Vitality Score (energy and fatigue) of ≤47. Multivariate logistic regression analysis was used to determine predictors of fatigue development 6 months poststroke.

Results—

The prevalence of fatigue was 30% (28% in men and 33% in women). There was a clear association between increased prevalence of fatigue and advancing age. The only baseline variables independently associated with an increased risk of developing fatigue at 6 months poststroke were prestroke incontinence and being of New Zealand European ethnicity. Being independent and living alone at baseline were associated with significant reduction in the risk of being fatigued at 6 months poststroke. Severe depression at 6 months was significantly and independently associated with being fatigued.

Conclusions—

The prevalence of fatigue found in our study is at the lower level of range reported in other studies. The prevalence of fatigue increased with advancing age, as found in most previous studies. Because fatigue can have a negative impact on stroke recovery, particular attention needs to be paid to those who are older, incontinent before stroke, and those who report severe symptoms of depression at 6 months after stroke.
Red Meat Consumption and Risk of Stroke
Authors: Kaluza Joanna , Wolk Alicja , Larsson Susanna C.
Published: August 2012

Background and Purpose—

Prospective studies of red meat consumption and risk of stroke have provided inconsistent results. We performed a meta-analysis to summarize the evidence regarding the effects of red meat (fresh, processed, and total) consumption on stroke risk.

Methods—

Studies were identified by searching the PubMed database through May 26, 2012, and by reviewing the reference lists of retrieved articles. Prospective studies that reported relative risks (RR) with 95% confidence intervals (CI) for the association between red meat consumption and risk of stroke were eligible. Results were combined using a random-effects model.

Results—

Five articles including results from 6 prospective studies with 10 630 cases of stroke and 329 495 participants were included in the meta-analysis. For each serving per day increase in fresh red meat, processed meat, and total red meat consumption, the RR (95% CI) of total stroke were 1.11 (1.03–1.20), 1.13 (1.03–1.24), and 1.11 (1.06–1.16), respectively, without heterogeneity among studies (
P
>0.16). Among 4 articles with results for stroke subtypes, the risk of ischemic stroke was positively associated with consumption of fresh red meat (RR, 1.13; 95% CI, 1.00–1.27), processed meat (RR, 1.15; 95% CI, 1.06–1.24), and total red meat (RR, 1.12; 95% CI, 1.05–1.19); no statistically significant associations were observed for hemorrhagic stroke.

Conclusion—

Results from this meta-analysis indicate that consumption of fresh red meat and processed red meat as well as total red meat is associated with increased risk of total stroke and ischemic stroke, but not hemorrhagic stroke.
An Expanded Derivation of the Threshold Structure of the Polytomous Rasch Model That Dispels Any “Threshold Disorder Controversy”
Authors: Andrich David
Published: August 2012

Responses to items with formats in more than two ordered categories are ubiquitous in education and the social sciences. Because the putative ordering of the categories reflects an understanding of what it means to have more of the variable, it seems mandatory that the ordering of the categories is an empirical property of the assessments and not merely a property of the model used to analyze them. To provide an unequivocal interpretation of category ordering in rating formats, this article expands the original derivation of the polytomous Rasch model for ordered categories. To do so, it integrates a complex of mathematical relationships among response spaces from which a space of experimentally independent Bernoulli variables, characterized by Rasch’s simple logistic model, can be inferred. From this inference, the article establishes the necessary and sufficient evidence to test the hypothesis that the required ordering of the categories is an empirical property of the assessments. This expanded derivation, which exposes how Adams, Wu, and Wilson (2012) misconstrue the model and its implications, is intended to dispel the so-called disordered threshold controversy they claim exists.
Individual, household and administrative area levels of social capital and their associations with mental health: A multi-level analysis of cross-sectional evidence
Authors: Han Sehee , Lee Hee-Sun
Published: August 2012

Background:

Research has seldom considered social capital at the individual, household and administrative area level simultaneously and examined its association with mental health.

Aim:

The main purpose of this study was to examine the association between social capital and mental health while controlling for various confounders at multiple levels using multi-level analysis and operationalizing social capital at the individual, household and administrative area level.

Methods:

This study used cross-sectional data from the 2010 Seoul Welfare Panel Study conducted by the Seoul Welfare Foundation (participation rates for the household and household members were 87.6% and 87.5%, respectively).

Results and conclusions:

The main finding of this study was that organizational participation (B = 0.132, p < .001) and perceived helpfulness (B = 0.129, p < .001) were positively associated with mental health. This study also found that perceived helpfulness was positively associated with mental health (B = 0.070, p < .001). However, it did not find a significant association between the contextual level of social capital and mental health. The results indicate that the different dimensions of social capital may act differently to mental health depending on the level.
Prevalence and predictors of stress disorders following two earthquakes
Authors: Yuan Kang Chuan , Ruo Yao Zhao , Zhen Yu Shi , Xu Dong Zhao , Jian Zhong Yang , Edwards Jason Glen , Edwards Glen David
Published: August 2012

Background:

Studies about stress disorders following a disaster have mainly been based on single-event trauma with little emphasis on multiple traumas.

Aims:

This study investigated the prevalence and predictors of stress disorders following two earthquakes in China.

Methods:

Subjects were randomly sampled from 11 villages in rural China. A total of 624 subjects were administered with the 12-item General Health Questionnaire (GHQ-12), Symptom Checklist -90-R (SCL-90-R), Coping Style Scale and Social Support Rating Scale. This was followed by a structural clinical interview using the Chinese translation of the Structured Clinical Interview for Diagnostic and Statistical Manual (DSM)-IV-TR axis 1 disorders (SCID-I-P) for acute stress disorder (ASD) and post-traumatic stress disorder (PTSD).

Results:

The prevalence of ASD and PTSD was 15% and 29%, respectively. Regression analysis indicated that high intensity of trauma exposure, lower educational level, subjective feeling of economic status and psychological stress after the first earthquake significantly predicted the outcome of PTSD.

Conclusions:

The study suggested that the prevalence of stress disorders in two earthquakes were higher than that experienced in a single disaster. The intensity of trauma exposure, low educational level, bad subjective feeling of economic status, and psychological stress after the first earthquake could be used to identify survivors at risk of developing PTSD in two earthquakes.
Risk Factors for Otolaryngological Foreign Bodies in Eastern Poland
Authors: Rybojad Beata , Niedzielski Artur , Niedzielska Grażyna , Rybojad Paweł
Published: August 2012

Objective

To identify the sociodemographic characteristics and risk factors associated with suspected foreign bodies in the ear, nose, throat, airway, and esophagus among Polish children.

Study Design

Case series with chart review.

Setting

Tertiary care medical center.

Subjects and Methods

A retrospective analysis of the medical records of patients hospitalized for a suspected foreign body (FB) between 1998 and 2008 was conducted. Data regarding place of residence, presence of siblings, parents’ educational status, seasonality, psychomotor development, age, and sex were collected and statistically analyzed.

Results

Of the 1011 patients with suspected foreign body insertion, 849 (84%) had a positive diagnosis. Of the confirmed foreign bodies, 96 were found in the tracheobronchial tree, 142 were found in the esophagus, and 611 were located in the external auditory canals, nasopharyngeal passage, tonsils, auricles, or lips. Sociodemographically, 596 of the children came from urban areas, with a preponderance of males (55%). Objects were removed more frequently in summer and autumn (60%). Children with siblings (53%) predominated. The majority of patients (52%) had parents with an elementary education. Food was the most frequent foreign body in children under 3 years of age. Patients with delayed psychomotor development constituted 1.6% of the analyzed population.

Conclusions

Being male, 1 to 3 years of age, belonging to an urban family with siblings, and having parents with an elementary education increased the risk of foreign body insertion. Training caregivers about proper nutrition and safety rules when playing with children can reduce the risk of accidents related to foreign body insertion.
Between the Notes: A Musical Understanding of Change in Group Analysis
Authors: Wotton Linde
Published: August 2012

This article brings together insights from the fields of communicative musicality and group analysis and suggests that the matrix should be understood as a musical process. Linking the social and the biological, this offers an explanation of many of the mechanisms that are fundamental, both to our nature as social to the core and to the group process (particularly belonging and resonance), but which remain outside of awareness. This musical understanding leads to a recasting of the role of the group analyst, not as conductor but as tonic or home note and a view of change as the development of greater flexibility in relating. The basis for the analogy between music and the group process is, I suggest, the creative space from which meaning emerges that is common to both—the interval in music and the intersubjective space in the group.
Modelling of the whey and cow manure co-digestion process
Authors: Hublin Andrea , Zelić Bruno
Published: August 2012

The production of renewable energy, a reduction of waste and prevention of environmental pollution promote the industrial application of anaerobic co-digestion for the treatment of agro-industrial organic waste. In this paper production of biogas/methane was studied by performing a series of laboratory batch experiments using whey and cow manure as substrates. The influence of substrate concentration, temperature and pH on biogas production was analysed. A mathematical model has been developed that describes the co-digestion process. The hydrolysis of proteins, lipids and cellulose has been modelled using first-order kinetics. Fermentation of sugars and amino acids, anaerobic oxidation of long chain fatty acids (LCFA), acetogenesis and methanogenesis have been described using an unstructured model based on Monod kinetic equations taking into account different inhibitory effects. Model applicability was demonstrated by comparing experimental results with the model simulation results.