bluuebunny/crossref_metadata_2025 huggingface dataset:
Salt and hypertension. Lessons from animal models that relate to human hypertension.
Authors: Tobian L
Published: August 2012

A high NaCl diet can raise blood pressure in both susceptible people and in susceptible animals, and the mechanisms are probably quite similar for both humans and animals. The possibly harmful effects of a high NaCl diet are not unexpected since both prehistoric man and mammals evolved in a low NaCl world. Evolutionary forces molded mammals to adapt well to a low sodium intake; the modern high NaCl intake goes "against the grain" of this adaptation. The high NaCl diet can cause premature mortality by raising blood pressure in susceptible people. We have new evidence that in a hypertensive setting, a high NaCl diet can increase mortality even though it does not cause a further rise of blood pressure. Multiple small cerebral infarcts are a partial cause of this excess mortality. Recent evidence also indicates that a high potassium diet reduces the rise of blood pressure caused by a high NaCl diet, whereas a low normal potassium intake encourages an NaCl-induced rise of blood pressure. It is the combination of kidneys that tends to retain NaCl together with a high NaCl intake that produces a rise in blood pressure. This combination tends to cause NaCl retention, which can trigger a rise in blood pressure in susceptible humans and animals. Such a rise in blood pressure can augment renal NaCl excretion and regain the previous NaCl balance. In the Dahl salt-sensitive (DS) rat, there are several renal abnormalities that would tend to encourage sodium retention. By analogy, renal "abnormalities" are probably present in people susceptible to hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)
Endothelial function in humans. Studies of forearm resistance vessels.
Authors: Kiowski W
Published: August 2012

The endothelium is increasingly recognized as a modulator of vascular tone, and evidence also is accumulating for an important role of the endothelium in humans in vivo. Endothelial release of prostacylin appears to regulate hyperemic blood flow after ischemia and muscle exercise, and the potent vasodilating properties of endothelium-derived relaxing factor (EDRF) are well established. Tonic release of EDRF plays an important role in the regulation of vascular tone in normal subjects, and a reduction of EDRF release in response to muscarinergic stimulation has been described in subjects with uncomplicated hypertension and also in hyperlipidemic patients. These observations point toward an early disturbance of endothelial function in disorders known as risk factors for the development of atherosclerosis. Furthermore, altered EDRF release and responsiveness to stimuli may be involved in the disturbed regulation of peripheral vascular tone in congestive heart failure. The physiological role of the vasoconstricting peptide endothelin-1 is not yet defined, but the study of the vascular actions of the peptide in humans has shown a vasodilating effect (for low dosages or when the vasconstricting effects are blocked), as well as a marked and long-lasting vasoconstricting effect. Although the mechanisms leading to vasodilation are not clear in humans, endothelin-1-induced vasoconstriction appears to be completely dependent on the activity of voltage-operated calcium channels and can be blocked by organic calcium antagonists but not by nitrovasodilators or EDRF. Further clarification of the role of the endothelium will provide a better understanding of circulatory physiology and pathophysiology and eventually may lead to the development of new therapeutic modalities.
The Zucker rat model of obesity, insulin resistance, hyperlipidemia, and renal injury.
Authors: Kasiske B L , O'Donnell M P , Keane W F
Published: August 2012

Although the pathogenesis of obesity in OZR is unknown, the association among hyperinsulinemia, insulin resistance, and hyperlipidemia suggests that investigations using OZR may help define how a number of vascular disease risk factors interact to cause end-organ damage. Like other rat strains, OZR do not develop atherosclerosis spontaneously. Nevertheless, in an endothelial injury model, atherosclerosis was worse in OZR than in LZR. Perhaps more intriguing is the fact that OZR develop spontaneous glomerular injury. Although the mechanisms important in the development and progression of glomerular injury in OZR remain to be clarified, both lipid abnormalities and glomerular hemodynamic alterations could play a role.
Obesity-associated hypertension. Hyperinsulinemia and renal mechanisms.
Authors: Hall J E , Brands M W , Hildebrandt D A , Mizelle H L
Published: August 2012

Hyperinsulinemia and insulin resistance have been postulated to link obesity and hypertension. Evidence supporting this concept derives mainly from epidemiological studies showing a correlation between insulin resistance, hyperinsulinemia, and blood pressure and from short-term studies suggesting that insulin has renal and cardiovascular actions that, if sustained, could elevate blood pressure. However, a cause-and-effect relation between insulin and hypertension has not been clearly established. Recent studies indicate that chronic hyperinsulinemia, similar to that found in obese hypertensive patients, did not raise blood pressure in normal dogs, even when renal excretory capability was reduced by prior removal of kidney mass. Chronic insulin infusion also failed to elevate blood pressure in dogs maintained on a high sodium intake and did not potentiate the long-term blood pressure responses to angiotensin II or norepinephrine. The presence or absence of insulin resistance may not be a major factor in determining the blood pressure response to hyperinsulinemia since chronic insulin infusion also failed to cause hypertension in obese, insulin-resistant dogs. Although hyperinsulinemia causes transient sodium retention, sustained decreases in renal excretory capability sufficient to cause chronic hypertension did not occur in dogs. In rats, insulin infusion causes small increases in blood pressure, although several characteristics of the hypertension (e.g., salt-sensitivity) differ from those observed in obese human hypertensive patients. Whether humans more closely resemble dogs or rats with respect to their long-term cardiovascular responses to insulin remains to be determined. However, very high insulin levels in humans with insulinoma do not cause hypertension, and several studies suggest that there is only a weak correlation between plasma insulin concentration and blood pressure in normal humans. Therefore, additional factors besides hyperinsulinemia per se may be responsible for a major component of obesity-associated hypertension.
Renal denervation normalizes pressure and baroreceptor reflex in high renin hypertension in conscious rats.
Authors: Oliveira V L , Irigoyen M C , Moreira E D , Strunz C , Krieger E M
Published: August 2012

High renin hypertension is usually accompanied by impairment of the baroreceptor reflexes. This feature has been mostly ascribed to overactivity of the renin-angiotensin system. However, renal nerves could also modulate the baroreceptor reflexes. In the present experiments, the effect of renal denervation on the depressed baroreceptor reflexes was studied in rats subjected to aortic ligation between the renal arteries. Renal denervation of the ischemic kidney was performed at the same time as aortic ligation. The resulting effects on arterial pressure, heart rate, plasma renin activity, and baroreceptor reflex control of heart rate were studied 10-12 days after ligation and denervation. Aortic ligation induced high levels of mean arterial pressure (166 +/- 6 versus 110 +/- 3 mm Hg in controls), heart rate (380 +/- 9 versus 352 +/- 8 beats per minute in controls), and plasma renin activity (44 +/- 5 versus 6 +/- 1.2 ng angiotensin I/ml/hr). The baroreceptor reflex sensitivity for bradycardia and tachycardia was significantly reduced (-0.18 +/- 0.04 and -0.18 +/- 0.05, respectively, versus -2.3 +/- 0.01 and -2.4 +2- 0.1 beats per minute per mm Hg in controls). Denervation of the ischemic kidney attenuated the development of hypertension in aortic-ligated rats (122 +/- 3 mm Hg), lowering heart rate (319 +/- 8 beats per minute) and normalizing baroreceptor reflex sensitivity to bradycardia (-2.0 +/- 0.2 beats per minute per mm Hg) and to tachycardia (-4.0 +/- 0.1 beats per minute per mm Hg). Plasma renin activity was also normalized (4.3 +/- 2.4 ng angiotensin I/ml/hr).(ABSTRACT TRUNCATED AT 250 WORDS)
Mild exercise decreases plasma endogenous digitalislike substance in hypertensive individuals.
Authors: Koga M , Ideishi M , Matsusaki M , Tashiro E , Kinoshita A , Ikeda M , Tanaka H , Shindo M , Arakawa K
Published: August 2012

Changes in a plasma endogenous digitalislike substance were investigated in relation to the antihypertensive mechanism of mild exercise. Fifteen women with mild essential hypertension and seven normotensive female volunteers were divided into exercised hypertensive (n = 10), nonexercised hypertensive (n = 5), and nonexercised normotensive (n = 7) groups. A 4-week general clinical observation period preceded the study period of 10 weeks. The exercised hypertensive individuals were treated with a lactate threshold exercise that corresponded to approximately 50% of the maximum oxygen consumption three times a week, whereas the nonexercised groups were observed at the outpatient clinic as control groups. In the exercised group, systolic blood pressure fell by 7 mm Hg (p = 0.05), diastolic by 6 mm Hg (p less than 0.01), and mean blood pressure by 7 mm Hg (p less than 0.01) after 10 weeks. The reduction in the plasma endogenous digitalislike substance was significant after 7 (-1.02 ng/ml, p less than 0.05) and 10 (-1.04 ng/ml, p less than 0.05) weeks in this group. It positively correlated with the reduction in diastolic (r = 0.70, p less than 0.05) or mean (r = 0.66, p less than 0.05) blood pressure and with changes in plasma norepinephrine (r = 0.76, p less than 0.05). The mean corpuscular volume of erythrocytes decreased (-1.7 fl, p less than 0.01) after 10 weeks of exercise, and the plasma volume index tended to decrease (-108 ml/m2, p = 0.28). In the control groups, significant changes in blood pressure and plasma endogenous digitalislike substance were not observed.(ABSTRACT TRUNCATED AT 250 WORDS)
Severe hypertension induces disturbances of renal autoregulation.
Authors: Almeida J B , Saragoça M A , Tavares A , Cezareti M L , Draibe S A , Ramos O L
Published: August 2012

To study if the severity of hypertension could be associated with disturbances of the autoregulation of renal blood flow and glomerular filtration, we compared the renal hemodynamic and functional responses to acute blood pressure reductions of a group of patients with moderate essential hypertension (n = 10) with those of a group of patients with severe hypertension (n = 10). Blood pressure was reduced to normal levels by a stepwise infusion of sodium nitroprusside, and effective renal blood flow (by 131I-hippuran), glomerular filtration rate (by endogenous creatinine clearance), and filtration fraction were determined. After acute blood pressure normalization, effective renal blood flow and glomerular filtration rate were significantly reduced in patients with severe hypertension (-41.6 +/- 8.3% and -44.7 +/- 6.8%, respectively; p less than 0.01 for both) but not in those with moderate hypertension (+4.9 +/- 9.1% and +6.2 +/- 13.3%, respectively; NS). Filtration fraction remained unchanged in both groups. These results show that severe but not moderate essential hypertensive patients have a displacement to the right of the lower limit of the renal autoregulation curve due to impaired vasodilation to maintain adequate renal blood flow during acute reductions of blood pressure. This impairment may be due to anatomic or functional defects of preglomerular vessels, or to both. Furthermore, the inability to maintain adequate glomerular filtration in these circumstances shows that patients with severe hypertension also have an impaired ability to adjust postglomerular vasomotor tone in the face of reductions in glomerular blood flow.
Hyperinsulinemia in normotensive offspring of hypertensive parents.
Authors: Grunfeld B , Balzareti M , Romo M , Gimenez M , Gutman R
Published: August 2012

Hyperinsulinemia and insulin resistance have been extensively reported in adult patients with essential hypertension. The aim of this study was to examine serum glucose and insulin levels both in the fasting state and after 0.25 g/kg IV glucose and to relate those findings to the status of intracellular Na+ and red blood cell Na(+)-Li+ countertransport in a population of 21 normolipemic normotensive offspring of hypertensive parents (N-EH) and 13 control children without a history of parental essential hypertension or diabetes mellitus matched for age, body mass index, and pubertal stage. Offspring of hypertensive parents presented significantly higher serum insulin levels both after an overnight fast (17.4 +/- 1.6 versus 11.6 +/- 1.6 microU/mL in control [mean +/- SEM], P < .01) and after intravenous glucose than control subjects (insulin area under the curve, 3015 +/- 310 and 2057 +/- 234 microU/mL per hour, respectively, P < .01). No relation could be established between the high red blood cell Na(+)-Li+ countertransport (343 +/- 22 versus 215 +/- 15 mumol/L per hour, N-EH versus control; P < .002) or high intracellular Na+ (9.8 +/- 0.28 versus 8.7 +/- 0.36 mEq/L, N-EH versus control) and hyperinsulinemia found in children of hypertensive parents. We conclude that the time precedence of hyperinsulinemia (and possibly insulin resistance) over the appearance of clinical hypertension in a high-risk population further supports the contention that an abnormal insulin action may play a pathogenetic role in essential hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)
Expression of nitric oxide synthase by cytokines in vascular smooth muscle cells.
Authors: Koide M , Kawahara Y , Tsuda T , Nakayama I , Yokoyama M
Published: August 2012

In cultured vascular smooth muscle cells, the baseline mRNA and protein levels of an inducible type of nitric oxide synthase were barely detectable. Interferon gamma, tumor necrosis factor-alpha, and interleukin-1 beta each markedly increased mRNA and protein levels of this enzyme in parallel with the production of nitrite, a stable oxidative metabolite of nitric oxide. Actinomycin D abolished the cytokine-induced increases in mRNA levels and nitrite production. Cycloheximide, which abolished the cytokine-induced increase in nitrite production, had no effect on the interferon-gamma-induced increase in mRNA levels but partially inhibited that induced by interleukin-1 beta and markedly inhibited that induced by tumor necrosis factor-alpha. Transforming growth factor-beta 1, which inhibited the interferon gamma-, interleukin-1 beta-, and tumor necrosis factor-alpha-induced nitrite production, did not affect the increases in mRNA levels caused by these cytokines. Transforming growth factor-beta 1, however, significantly inhibited the increase in protein levels caused by these cytokines. These findings suggest that interferon gamma directly induces the expression of the inducible nitric oxide synthase gene, whereas tumor necrosis factor-alpha and interleukin-1 beta induce it, at least in part, via the induction of intermediary protein(s), and that transforming growth factor-beta 1 inhibits cytokine-induced nitric oxide production by blocking the posttranscriptional synthesis of inducible nitric oxide synthase.
Enhanced vasodilatation in essential hypertension by calcium channel blockade with verapamil.
Authors: Hulthén U L , Bolli P , Amann F W , Kiowski W , Bühler F R
Published: August 2012

The dependency of arteriolar tone on calcium influx was studied in 11 patients with essential hypertension (EH) and compared to 11 age-matched normotensive subjects (NT) by measuring the forearm blood flow response to intraarterial infusion of the calcium channel blocker verapamil (Verap) and the non-specific vasodilator sodium nitroprusside (Nip) using venous occlusion plethysmography. Verap in incremental dosages from 1 to 75 micrograms/100 ml forearm tissue induced a greater increase in forearm blood flow ( delta FAF) in EH then in NT, whereas there was no significant difference in delta FAF following Nip 1,2 micrograms/100 ml tissue. Delta FAF to Verap as adjusted for delta FAF to Nip was still greater in EH than in NT. Delta FAF to all dosages of Verap correlated positively with basal plasma epinephrine concentration in EH. At the two highest dosages of Verap, systemic blood pressure fell in EH, and the Verap-induced vasodilator (as adjusted for the response to Nip) correlated negatively to plasma renin activity or plasma angiotensin II concentration. These findings support the concept of an increased dependency of arteriolar tone on calcium influx in EH, which is related to the activity of the sympathetic nervous system. This association may be due to a common underlying derangement in transmembranous ionic fluxes in smooth muscle cells and sympathetic neurons in EH.
Relative roles of sodium and calcium ions in the steroidogenic response of isolated rate adrenal glomerulosa cells.
Authors: Schiffrin E L , Gutkowska J , Lis M , Genest J
Published: August 2012

To study the relative roles of sodium (Na+) and calcium ions (Ca2+) in the response of adrenal glomerulosa cells, we investigated the effects of different Na+ concentrations in the incubation media and the actions of substances that interfere with Ca2+ fluxes. Basal aldosterone secretion and response to angiotensin II (AII), adrenocorticotropic hormone (ACTH), or potassium (K+) were dependent on extracellular Na+ concentration. Veratridine, a Na+ channel opener that dissipates Na+ gradients, blocked the stimulated steroidogenic response. Mersalyl acid and tetracaine, which are potent Ca2+ antagonists, blocked the effects of aldosterone secretagogues. Divalent cations with Ca2+ antagonistic action such as manganese M(n2+), nickel (Ni2+), and cobalt (Co2+) blocked the aldosterone secretory response to AII, ACTH, and K+. Barium (Ba2+) and strontium (Sr2+), known to mimick Ca2+ effects, increased or did not affect responses of the glomerulosa cells. Sodium vanadate, an inhibitor of ATP-dependent Ca2+ translocation, did not alter the stimulated aldosterone responses. Trifluoperazine (10(-6) M), an inhibitor of calmodulin, blocked AII and K+-induced aldosterone secretion, but was partially effective on ACTH-stimulated aldosterone output only at a concentration of 10(-5) M. The actions of ouabain on aldosterone biosynthesis were similarly affected by all these drugs. Thus, both extracellular Na+ and Ca2+ appear to play a role in the steroidogenic response of isolated glomerulosa cells. The intracellular action of Ca2+ may involve a calmodulin-like protein. The effects of ACTH are only partially dependent on Ca2+ as a second intracellular messenger.
Renal arachidonic acid metabolism. The third pathway.
Authors: Schwartzman M , Carroll M A , Ibraham N G , Ferreri N R , Songu-Mize E , McGiff J C
Published: August 2012

Cells were isolated from the outer medulla of the rabbit kidney, primarily from the thick ascending limb of Henle's loop (mTALH). These mTALH cells are heavily invested with a cytochrome P450-linked monooxygenase that represents the third pathway by which arachidonic acid is metabolized. After cell separation, approximately 80% of the cells proved to be mTALH in origin, based on electron microscopic criteria and immunofluorescent localization of Tamm-Horsfall protein, a specific marker for mTALH cells. The specific activity of alkaline phosphatase, a marker for proximal tubular cells, decreased threefold after separation of mTALH cells from outer medullary cells, associated with a fourfold increase in the capacity of the separated mTALH cells to metabolize arachidonic acid. Incubation of mTALH cells with 14C-arachidonic acid resulted in formation of oxygenated metabolites, identified as two peaks (P1 and P2), which accounted for 30 to 40% of the recovered radioactivity. Formation of prostaglandin E2 and F2 alpha accounted for only 3 to 5%. The chromatographic retention times of P1 and P2 were different from products of lipoxygenases. An inhibitor of cytochrome P450-dependent enzymes, SKF-525A (50 microM), reduced product formation by mTALH cells by more than 70%, while induction of cytochrome P450 increased product formation. Formation of P1 and P2 by cell-free homogenates of mTALH was totally dependent on the presence of nicotinamide adenine dinucleotide phosphate, reduced form (NADPH), which suggests a NADPH-dependent cytochrome P450-linked monooxygenase pathway. Vasopressin and calcitonin (10(-10) M to 10(-7) M) stimulated release of arachidonic acid metabolites from mTALH cells.(ABSTRACT TRUNCATED AT 250 WORDS)
Association Between Extracellular Matrix Expansion Quantified by Cardiovascular Magnetic Resonance and Short-Term Mortality
Authors: Wong Timothy C. , Piehler Kayla , Meier Christopher G. , Testa Stephen M. , Klock Amanda M. , Aneizi Ali A. , Shakesprere Jonathan , Kellman Peter , Shroff Sanjeev G. , Schwartzman David S. , Mulukutla Suresh R. , Simon Marc A. , Schelbert Erik B.
Published: August 2012

Background—

Extracellular matrix expansion may be a fundamental feature of adverse myocardial remodeling, it appears to be treatable, and its measurement may improve risk stratification. Yet, the relationship between mortality and extracellular matrix is not clear because of difficulties with its measurement. To assess its relationship with outcomes, we used novel, validated cardiovascular magnetic resonance techniques to quantify the full spectrum of extracellular matrix expansion not readily detectable by conventional cardiovascular magnetic resonance.

Methods and Results—

We recruited 793 consecutive patients at the time of cardiovascular magnetic resonance without amyloidosis or hypertrophic cardiomyopathy as well as 9 healthy volunteers (ages 20–50 years). We measured the extracellular volume fraction (ECV) to quantify the extracellular matrix expansion in myocardium without myocardial infarction. ECV uses gadolinium contrast as an extracellular space marker based on T1 measures of blood and myocardium pre— and post–gadolinium contrast and hematocrit measurement. In volunteers, ECV ranged from 21.7% to 26.2%, but in patients it ranged from 21.0% to 45.8%, indicating considerable burden. There were 39 deaths over a median follow-up of 0.8 years (interquartile range 0.5–1.2 years), and 43 individuals who experienced the composite end point of death/cardiac transplant/left ventricular assist device implantation. In Cox regression models, ECV related to all-cause mortality and the composite end point (hazard ratio, 1.55; 95% confidence interval, 1.27–1.88 and hazard ratio, 1.48; 95% confidence interval, 1.23–1.78, respectively, for every 3% increase in ECV), adjusting for age, left ventricular ejection fraction, and myocardial infarction size.

Conclusions—

ECV measures of extracellular matrix expansion may predict mortality as well as other composite end points (death/cardiac transplant/left ventricular assist device implantation).
Circulation: Heart Failure
Editors' Picks
Authors:   The Editors
Published: July 2012

The following articles are being highlighted as part of
Circulation's
Topic Review series. This series summarizes the most important manuscripts, as selected by the editors, published in
Circulation
and the
Circulation
subspecialty journals. The studies included in this article represent the Editors' Picks for each
Circulation: Heart Failure
issue published in 2011.
The impact of spirituality on eating disorder symptomatology in ethnically diverse Canadian women
Authors: Boisvert Jennifer A , Harrell W Andrew
Published: August 2012

Background:

There is currently a gap in our knowledge of how eating disorder symptomatology is impacted by spirituality and religiosity. To date, studies examining the role of ethnicity in women’s self-reported levels of eating disorder symptomatology have neglected the roles of spirituality and religiosity.

Aims:

This study addresses this gap in the literature by investigating ethnicity, spirituality, religiosity, body shame, body mass index (BMI) and age in relation to eating disorder symptomatology in women.

Methods:

A representative non-clinical sample of ethnically diverse Canadian women (N = 591) was surveyed.

Results:

Younger women, particularly those with higher body shame, BMI and lower spirituality, reported more eating disorder symptomatology. Hispanic and Asian women had higher body shame and lower BMI compared to white women. Spirituality was more strongly related to eating disorder symptomatology than religiosity.

Conclusions:

This is the first study identifying interactive relationships between ethnicity, spirituality, body shame, BMI and age on eating disorder symptomatology in women. Particularly significant is that higher spirituality was related to a lower level of eating disorder symptomatology. These findings have important implications for treatment and women’s physical and psychological health and wellness.
Contesting Urban and Rural Space in Desakota Regions of Taiwan—A Case Study of I-Lan County
Authors: SHIH C.S. Stone , Chi Chang-Liang
Published: July 2012

The article focuses on the analysis of the desakotasi (village-city process) in Taiwan’s local context of I-Lan County. Particular attention is paid to the manner in which political conflicts have shaped the urbanization process in I-Lan County over the last 20 years. Those conflict points include primarily the construction of Industrial Zones (IZs) and Taipei-I-Lan super highway promoted by the ruling Kuomintang Party (KMT), which were designed to increase Taiwan’s international competitiveness. But such measures were opposed by the Democratic Progressive Party (DPP) with an ideology of local first. Local magistrates issued a series of environmental protection policies against the developmental strategies of the central state, the ruling Kuomintang. In the following years, the continuing rotation of political parties created conflict that brought demonstration at the local level. These developments were affected by international and national developments that led to a restructuring of economic space in Taiwan particularly processes of urban expansion that led to a steady decline of agriculture.

The significant push-and-pull effect of contesting spaces in political conflicts between KMT- and DPP-controlled periods could be evidenced by: (1) the decline or prosperity of the Industrial Zones and Suao township; (2) the enlargement of urban cores like I-Lan City and Luodong Township; and (3) the formation of a mixed space of urban–rural corridor. I-Lan County, which so long remained in the shadow of the Taipei metropolis, is now increasingly integrated into the Taipei metropolitan region. And its future relies upon the resolution of the political conflicts surrounding environmental protection and the spatial reconstruction of the region so that its desakota heritage may be preserved.
Transitioning Challenges Faced by Chinese Graduate Students
Authors: Huang Ying
Published: July 2012

This literature review examines transitioning challenges faced by Chinese international students who pursue graduate degrees in the United States. Based on existing research on adulthood in U.S. and Chinese contexts and the features of Chinese graduate students, Chinese adults, and international students as learners in Western countries, the examination includes the adult learning environment in American graduate education, the demographic features of Chinese international students who pursue graduate degrees in the United States, and the challenges they are confronted with inside and outside the classroom. The emphasis is given to two types of transitions experienced by Chinese graduate students in the United States: learning to live into adulthood and learning to learn in an adult learning setting. Findings of this literature review shed light on understanding Chinese graduate students as a particular group of learners, provide practical suggestions for practitioners in the United States and other Western countries who teach or mentor Chinese graduate students, and inform future research on Chinese international students.
Contribution of blood viscosity in the assessment of flow-mediated dilation and arterial stiffness
Authors: Parkhurst Kristin L , Lin Hsin-Fu , DeVan Allison E , Barnes Jill N , Tarumi Takashi , Tanaka Hirofumi
Published: July 2012

Flow-mediated dilation (FMD) is a non-invasive index of endothelial function. In an attempt to standardize FMD for shear stimulus, shear rate (velocity/diameter), rather than shear stress (viscosity*velocity/diameter), is commonly used as a surrogate measure, although it is limited by individual differences in blood viscosity. The purpose of this study was to determine the contribution of whole blood viscosity to FMD and other key measures of vascular function. Blood viscosity, FMD, carotid artery compliance, and carotid–femoral pulse wave velocity (cfPWV) were measured in 98 apparently healthy adults varying widely in age (18–63 years). Whole blood viscosity was not significantly correlated with FMD, cfPWV, or carotid artery compliance. Shear rate was a stronger correlate with FMD than shear stress that takes blood viscosity into account ( r = 0.43 vs 0.28). No significant differences were observed between whole blood viscosity and traditional risk factors for cardiovascular disease. Age was positively correlated with cfPWV ( r = 0.65, p < 0.001) and negatively correlated with FMD ( r = −0.24, p < 0.05) and carotid artery compliance ( r = −0.45, p < 0.01). Controlling for viscosity did not reduce the strength of these relations. These results indicate that whole blood viscosity does not significantly impact measures of vascular function and suggests that the common practice to use shear rate, rather than shear stress, in the adjustment of FMD is valid.
Peripheral pulmonary artery stenosis masquerading as pulmonary hypertension: A diagnostic and therapeutic challenge
Authors: Kushner Tatyana , Halperin Jonathan L , Nair Ajith P , Fuster Valentin , Love Barry A
Published: July 2012

Isolated peripheral pulmonary artery stenosis presenting in adulthood is an uncommon cause of right ventricular hypertension and may be misdiagnosed as primary or thromboembolic pulmonary hypertension. Treatment consists of balloon angioplasty and stenting of the affected vessels, although the procedure can be complicated by reperfusion pulmonary edema.
Tracking visual segmentation: connecting semiotic and cognitive perspectives
Authors: Boeriis Morten , Holsanova Jana
Published: July 2012

This article introduces a new methodology for deriving the dynamics of visual segmentation in relation to the underlying cognitive processes involved. The method combines social semiotics approaches to visual segmentation with eye-tracking studies on authentic image viewing and simultaneous image description. The authors’ thesis is that visual segmentation suggested by the social semiotic approach is traceable in the behaviour of the viewers who perceive images while creating meaning. From this perspective, visual zooming is seen as both perceptually, cognitively, grammatically and analytically relevant. The interdisciplinary approach developed in the article presents new perspectives on the ways images are segmented and interpreted.
Comprehension of multimedia health information among older adults with chronic illness
Authors: Morrow Dan , D’andrea Laura , Stine-Morrow Elisabeth A.L. , Shake Matthew , Bertel Sven , Chin Jessie , Kopren Katie , Gao Xuefei , Conner-Garcia Thembi , Graumlich James , Murray Michael
Published: July 2012

The authors explored knowledge effects on comprehension of multimedia health information by older adults (age 60 or older). Participants viewed passages about hypertension, with text accompanied by relevant and irrelevant pictures, and then answered questions about the passage. Fixations on text and pictures were measured by eye-tracking. Participants with more knowledge of hypertension understood the passages better. This advantage was related to how they processed the passages: while knowledge differences were unrelated to overall time viewing displays, relationships between allocation and knowledge emerged when the data were partitioned into phases (during and after first reading the text). More knowledgeable participants spent relatively more time fixating text than pictures during the first pass. After this pass, they spent more time viewing the relevant picture rather than re-reading, with some evidence that this strategy was associated with comprehension. The findings have implications for designing multimedia education materials and analyzing eye-tracking measures during multimedia learning.
Interactive software for multimodal analysis
Authors: O’Halloran Kay L. , Podlasov Alexey , Chua Alvin , K.L.E Marissa
Published: July 2012

This article presents the design and functionalities of interactive software for multimodal analysis currently being developed in the Multimodal Analysis Lab, Interactive Digital Media Institute (IDMI) at the National University of Singapore. The software is being used for the annotation, analysis, search and retrieval of semantic patterns in unified but complex semiotic acts – for example, the interaction of gesture, gaze, intonation, camera angle, and music in a film. In addition to providing a digital platform for multimodal analysis, the software provides the site for further development of multimodal theory as the analytical techniques and tools produce insights into the nature of the multimodal phenomena. The approach is located within the digital humanities paradigm that promotes the use of computer techniques and technologies for humanities, arts, and social science research.
Looking at the Russian health care system: through the eyes of patients with diabetes and their physicians
Authors: Kühlbrandt Charlotte , Basu Sanjay , Mckee Martin , Stuckler David
Published: August 2012

Aims

People with diabetes are well placed to evaluate and to assess the performance of health systems. We take the perspective of people living with diabetes and those caring for them to gain insights into how the contemporary Russian health system works for them.

Methods

We conducted 15 semi-structured interviews with patients with diabetes and physicians in rural and urban settings, in public and private sectors. Interviewees were identified using snowball sampling.

Results

Patients worried about high and rising costs of care, while physicians noted concerns about lack of time to treat patients adequately. Although all specifically diabetes-related services are free of charge, patients requiring urgent surgery often face high user fees, either to bypass waiting lists in state facilities or to be treated immediately in a private institution. These ‘hidden’, out-of-pocket payments impact adversely on equity and act as a barrier to timely care.

Conclusions

Although reform of health services in Russia has led to improvements in quality of care for diabetes, many gaps remain, particularly for management of complications. This paper provides further evidence of how people with diabetes can shed light on the reality, as opposed to the rhetoric of health system reform, especially in middle-income countries.
Hierarchical Naming in Milton’s Paradise Lost and Twain’s Diaries of Adam and Eve
Authors: Cantor Rebecca Guess
Published: July 2012

AbstractMark Twain — author, wit, philosopher, and self-named man — used names and naming throughout his works, not simply to add color, interest, or even characterization, but to shed light on the power struggles between people at different levels of nineteenth-century American society. Twain’s ‘Extracts from Adam’s Diary’ and ‘Eve’s Diary,’ which were directly influenced by one of his greatest literary influences — John Milton, are especially saturated with active naming. In Paradise Lost, Milton describes a hierarchically struc- tured naming system that separates angels from fallen angels, God from man, and man from woman. In Twain’s versions of the creation story, he inverts Milton’s naming structure, instead using naming to demonstrate his anti-imperialist ideals through the dominant naming of Eve.
Myeloid skewing in murine autoimmune arthritis occurs in hematopoietic stem and primitive progenitor cells
Authors: Oduro Kwadwo A. , Liu Fang , Tan Qing , Kim Chan-Kyu , Lubman Olga , Fremont Daved , Mills Jason C. , Choi Kyunghee
Published: August 2012

Skewing toward myeloid cell production is often observed in chronic inflammation and autoimmune diseases. Herein, we determined whether persistent myeloid activation and proinflammatory output occurring in pathologic conditions is at the level of hematopoietic stem and primitive progenitor cells (HSPPCs). By using a mouse arthritis model, we found that even though HSPPCs in arthritis still retained the capacity to differentiate into different lineages, they acquired enhanced in vitro and in vivo propensity in a disease-dependent manner to generate myeloid cells, the key perpetrators of tissue damage in arthritis. This myeloid skewing was cell intrinsic, as arthritic HSPPCs up-regulate myeloid-specific transcripts including S100a8. Exogenous S100a8 promoted myeloid cell output from wild-type HSPPCs, suggesting mechanistic involvement of this gene in the myeloid priming that occurs in arthritic HSPPCs. Therefore, our results indicate that in arthritic mice, HSPPCs adopt a pathologic state that favors disease persistence.
Genetic parameters of infectious bovine keratoconjunctivitis and its relationship with weight and parasite infestations in Australian tropical Bos taurus cattle
Authors: Ali Abdirahman A , O’Neill Christopher J , Thomson Peter C , Kadarmideen Haja N
Published: July 2012

Background

Infectious bovine keratoconjunctivitis (IBK) or ‘pinkeye’ is an economically important ocular disease that significantly impacts animal performance. Genetic parameters for IBK infection and its genetic and phenotypic correlations with cattle tick counts, number of helminth (unspecified species) eggs per gram of faeces and growth traits in Australian tropically adapted Bos taurus cattle were estimated.

Methods

Animals were clinically examined for the presence of IBK infection before and after weaning when the calves were 3 to 6 months and 15 to 18 months old, respectively and were also recorded for tick counts, helminth eggs counts as an indicator of intestinal parasites and live weights at several ages including 18 months.

Results

Negative genetic correlations were estimated between IBK incidence and weight traits for animals in pre-weaning and post-weaning datasets. Genetic correlations among weight measurements were positive, with moderate to high values. Genetic correlations of IBK incidence with tick counts were positive for the pre-weaning and negative for the post-weaning datasets but negative with helminth eggs counts for the pre-weaning dataset and slightly positive for the post-weaning dataset. Genetic correlations between tick and helminth eggs counts were moderate and positive for both datasets. Phenotypic correlations of IBK incidence with helminth eggs per gram of faeces were moderate and positive for both datasets, but were close to zero for both datasets with tick counts.

Conclusions

Our results suggest that genetic selection against IBK incidence in tropical cattle is feasible and that calves genetically prone to acquire IBK infection could also be genetically prone to have a slower growth. The positive genetic correlations among weight traits and between tick and helminth eggs counts suggest that they are controlled by common genes (with pleiotropic effects). Genetic correlations between IBK incidence and tick and helminth egg counts were moderate and opposite between pre-weaning and post-weaning datasets, suggesting that the environmental and (or) maternal effects differ between these two growth phases. This preliminary study provides estimated genetic parameters for IBK incidence, which could be used to design selection and breeding programs for tropical adaptation in beef cattle.
A Newfoundland cohort of familial and sporadic idiopathic pulmonary fibrosis patients: clinical and genetic features
Authors: Fernandez Bridget A , Fox George , Bhatia Rick , Sala Eric , Noble Barbara , Denic Nash , Fernandez Dzintra , Duguid Nigel , Dohey Amanda , Kamel Fady , Edwards Laura , Mahoney Krista , Stuckless Susan , Parfrey Patrick S , Woods Michael O
Published: August 2012

Background

Idiopathic pulmonary fibrosis (IPF) is an adult-onset Idiopathic Interstitial Pneumonia (IIP) usually diagnosed between age 50 to 70 years. Individuals with Familial Pulmonary Fibrosis (FPF) have at least one affected first or second-degree relative and account for 0.5-20% of cases.

Methods

We ascertained and collected DNA samples from a large population-based cohort of IPF patients from Newfoundland, Canada. For each proband, a family history was documented and medical records were reviewed. Each proband was classified as familial (28 patients) or sporadic (50 patients) and all 78 probands were screened for variants in four highly penetrant, adult-onset PF genes (SFTPC, SFTPA2, TERT,
TERC).

Results

Seventy-eight IPF probands were enrolled of whom 28 (35.9%) had a positive family history. These 28 familial patients led to the recruitment of an additional 49 affected relatives (total of 77 FPF patients). By age 60 years, 42% of the familial cohort had been diagnosed with PF compared with only 16% of the sporadic patient collection (χ2 = 8.77, p = 0.003). Mean age of diagnosis in the familial group was significantly younger than the sporadic group (61.4 years vs. 66.6 yrs, p = 0.012) with a wider age range of diagnosis (19–92 years compared with 47–82 years). Thirty-three of 77 (42.8%) FPF patients had a tissue diagnosis and all but five had usual interstitial pneumonia histology. Compared with other published case series, the familial IIP histologies were more homogeneous. Three of 28 familial probands (10.7%) and none of the 50 sporadic probands had pathogenic variants in the four genes tested. All three familial probands had mutations in TERT. Other phenotypes associated with telomerase deficiency were present in these families including cirrhosis, bone marrow hypoplasia and premature graying. Telomere length assays were performed on mutation carriers from two families and confirmed telomere-related deficiency.

Conclusion

The proportion of familial cases in our cohort is higher than any previously reported estimate and we suggest that this is due to the fact that Newfoundland cohort is ethnically homogeneous and drawn from a founder population. In our patient collection, diagnosis with IPF prior to age 45 years predicted familial disease. In two of the three TERT mutation families, the pedigree appearance is consistent with genetic anticipation. In the other 25 FPF families negative for mutations in known PF genes, we did not identify other telomerase associated medical problems (bone marrow dysfunction, cirrhosis) and we hypothesize that there are novel PF genes segregating in our population.
Estimation of sequencing error rates in short reads
Authors: Victoria Wang Xin , Blades Natalie , Ding Jie , Sultana Razvan , Parmigiani Giovanni
Published: July 2012

Background

Short-read data from next-generation sequencing technologies are now being generated across a range of research projects. The fidelity of this data can be affected by several factors and it is important to have simple and reliable approaches for monitoring it at the level of individual experiments.

Results

We developed a fast, scalable and accurate approach to estimating error rates in short reads, which has the added advantage of not requiring a reference genome. We build on the fundamental observation that there is a linear relationship between the copy number for a given read and the number of erroneous reads that differ from the read of interest by one or two bases. The slope of this relationship can be transformed to give an estimate of the error rate, both by read and by position. We present simulation studies as well as analyses of real data sets illustrating the precision and accuracy of this method, and we show that it is more accurate than alternatives that count the difference between the sample of interest and a reference genome. We show how this methodology led to the detection of mutations in the genome of the PhiX strain used for calibration of Illumina data. The proposed method is implemented in an R package, which can be downloaded from http://bcb.dfci.harvard.edu/∼vwang/shadowRegression.html.

Conclusions

The proposed method can be used to monitor the quality of sequencing pipelines at the level of individual experiments without the use of reference genomes. Furthermore, having an estimate of the error rates gives one the opportunity to improve analyses and inferences in many applications of next-generation sequencing data.
The ribonuclease Dis3 is an essential regulator of the developmental transcriptome
Authors: Hou Dezhi , Ruiz Miriam , Andrulis Erik D
Published: August 2012

Background

Dis3 is ribonuclease that acts directly in the processing, turnover, and surveillance of a large number of distinct RNA species. Evolutionarily conserved from eubacteria to eukaryotes and a crucial component of the RNA processing exosome, Dis3 has been shown to be essential in yeast and fly S2 cells. However, it is not known whether Dis3 has essential functions in a metazoan. This study inquires whether Dis3 is required for Drosophila development and viability and how Dis3 regulates the transcriptome in the developing fly.

Results

Using transgenic flies, we show that Dis3 knock down (Dis3KD) retards growth, induces melanotic tumor formation, and ultimately results in 2nd instar larval lethality. In order to determine whether Dis3KD fly phenotypes were a consequence of disrupting developmentally regulated RNA turnover, we performed RNA deep sequencing analysis on total RNA isolated from developmentally staged animals. Bioinformatic analysis of transcripts from Dis3KD flies reveals substantial transcriptomic changes, most notably down-regulation in early expressed RNAs. Finally, gene ontology analysis of this early stage shows that Dis3 regulates transcripts related to extracellular structure and remodelling, neurogenesis, and nucleotide metabolism.

Conclusions

We conclude that Dis3 is essential for early Drosophila melanogaster development and has specific and important stage-specific roles in regulating RNA metabolism. In showing for the first time that Dis3 is required for the development of a multicellular organism, our work provides mechanistic insight into how Dis3—either independent of or associated with the RNA processing exosome—participates in cell type-specific RNA turnover in metazoan development.