bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in Pulmonary Venous Return during Head-up Tilting in Man
Authors: Guazzi Marco , Tamborini Gloria , Maltagliati Anna 
Published: August 2015

1. In a supine position, the heart fills to close to the limits of pericardial constraint and the pericardium may act to redistribute central blood volume from the left side of the heart back to the more compliant lung.
2. We probed whether, and through which mechanisms, a redistribution of blood from the lungs to the left heart occurs during vertical displacement and compensates for reduced venous return.
3. We investigated 16 normal volunteers with Doppler-echocardiography during 20°, 40° and 60° head-up tilting. Tilting was stopped at 10 min in 10 subjects (group 1) and at 45 min in 6 subjects (group 2).
4. At 10 min we observed a reduction in right ventricular diastolic dimension and left ventricular end-diastolic pressure, as estimated by the difference between the duration of the pulmonary venous flow during atrial contraction (Z wave) and that of the mitral A wave. We also recorded a decrease during systole (X wave) and an increase during diastole (Y wave) of the pulmonary venous forward flow velocity. These variations were evident at 20° and became progressively greater with increasing degrees of tilting. In group 2, changes at 10 min and at 45 min for any degree of displacement were similar.
5. A decrease in right ventricular dimensions (ventricular interdependence) and underfilling of the lung compartment due to volume redistribution to the periphery (diminished lung contribution to pericardial constraint) augment compliance within the pericardial space, reduce downstream pressure for pulmonary venous return and move the pulmonary venous flow predominantly to ventricular diastole, allowing diastolic filling.
6. During head-up tilting a favourable interaction between heart and lungs increases compliance within the pericardial space and facilitates redistribution of blood from the lungs, resulting in a sustained compensation for the reduced venous return.
Seasonal Variations in Cyclic GMP Response on Whole-Body Cooling in Women with Primary Raynaud's Phenomenon
Authors: Leppert Jerzy , Ringqvist Åsa , Ahlner Johan , Myrdal Urban , Walker-Engström Marie-Louise , Wennmalm Åke , Ringqvist Ivar 
Published: August 2015

1. Primary Raynaud's phenomenon (PRP) is characterized by increased vasoconstrictor tone that develops during exposure to cold. The symptoms are most pronounced during the winter months with low outdoor temperature. The l-arginine—nitric oxide (NO)—cyclic GMP (cGMP) pathway plays an important role in counteracting vasospasm. The aim of the present study was to investigate if the venous cGMP response to whole-body cooling in women with PRP varied with the season of the year.
2. The study was performed as an open parallel-group comparison between women with PRP and healthy female controls during the winter months of February 1994 and 1995 and in the summer month of August 1994. Blood samples were drawn just before and 40 min after whole-body cooling.
3. There were no significant changes in venous cGMP after whole-body cooling in women with PRP during the winter months of February 1994 and 1995. Cold exposure in the summer month of August resulted, however, in a significant increase in venous cGMP (P &lt; 0.01). In contrast, the healthy women responded with a significant increase in venous cGMP on all three test occasions: February 1994 (P &lt; 0.05), August 1994 (P &lt; 0.05) and February 1995 (P &lt; 0.01)
4. A seasonal variation in venous cGMP response to whole-body cooling was observed only in women with PRP. Healthy women responded to cold exposure with an increase in venous cGMP during summer and winter, whereas females with PRP showed an increase only during summer. Results from the present study might indicate seasonal variation in the regulation of constitutive nitric oxide synthetase in women with PRP, which may contribute to new therapeutic approaches.
The 67gallium-transferrin Pulmonary Leak Index in Pneumonia and Associated Adult Respiratory Distress Syndrome
Authors: Groeneveld A. B. Johan , Raijmakers Pieter G. H. M. 
Published: August 2015

1. The aim of the study was to determine the role of increased microvascular protein permeability, as measured by the 67gallium (Ga)-transferrin pulmonary leak index, in pneumonia and associated adult respiratory distress syndrome (ARDS).
2. Eighteen consecutive patients with microbiologically confirmed pneumonia (radiographic infiltrates, purulent sputum) and needing respiratory monitoring (n = 2) or mechanical ventilation (n = 16) in the intensive care unit were studied prospectively. The pulmonary leak index using 67Ga-transferrin and 99mTc red blood cells was measured with a mobile probe system over both lung apices (normal value below 14.1 × 10−3 min−1) within 72 h of intensive care unit admission, and the lung injury score was calculated from radiographic, ventilatory and lung mechanical data.
3. Patients with pneumonia (lung injury score &lt;2.5, n = 10) had a lower (P &lt; 0.01) pulmonary leak index, averaged for both lungs, with a median of 23.9 [range (7.0–47.0) × 10−3 min−1] than patients with pneumonia-associated ARDS (lung injury score ≥2.5, n = 8), and an average pulmonary leak index of 37.5 [(23.4–144.2) × 10−3 min−1], so that, for all patients, the pulmonary leak index, averaged for both lungs, directly related to the lung injury score (rs = 0.61, P &lt; 0.01). A normal average pulmonary leak index excluded pneumonia-associated ARDS. Patients with unilateral pneumonia had a greater inter-lung difference (P &lt; 0.01) in the pulmonary leak index between affected and unaffected lung than patients with bilateral pneumonia. The index did not have prognostic significance.
4. The 67Ga-transferrin pulmonary leak index parallels the degree of radiographic, ventilatory and lung mechanical abnormalities of pneumonia and evolving ARDS. The data support the idea that the clinical manifestations of pneumonia culminating in ARDS directly relate to the degree of microvascular injury. Conversely, the pulmonary leak index may be used to monitor the effect of anti-inflammatory drugs in the adjunctive treatment for severe pneumonia aimed at circumventing mechanical ventilation in future studies.
Interactions between Endothelin-1-induced Contractions and Bronchodilators in Human Isolated Bronchi
Authors: Clayton Robert A. , Nally Jane E. , Thomson Neil C. , McGrath John C. 
Published: August 2015

1. The aim of this study was to compare the ability of four different bronchodilators (atrial natriuretic peptide, salbutamol, sodium nitroprusside and isosorbide dinitrate) to reverse and also to protect against contractions evoked by the spasmogens endothelin-1 and methacholine in human isolated bronchial rings.
2. Contractions evoked by either endothelin-1 or methacholine were reversed by atrial natriuretic peptide (10−9−10−6 mol/l), salbutamol (10−9−10−5 mol/l), sodium nitroprusside (10−9−10−5 mol/l) and isosorbide dinitrate (10−7−10−4 mol/l).
3. Sodium nitroprusside produced a significantly (P &lt; 0.05 for data points) greater mean maximal inhibition of endothelin-1-induced tone than methacholine-induced tone; however, the other dilators were equally effective at reversing either endothelin-1- or methacholine-induced contractions. Comparing sodium nitroprusside and salbutamol, sodium nitroprusside was significantly (P &lt; 0.05 for data set) less effective than salbutamol at reversing either endothelin-1- or methacholine-induced contractions.
4. To compare the ability of these bronchodilator substances to protect against spasmogen challenge, cumulative concentration—response curves to either endothelin-1 (10−10−3 × 10−7 mol/l) or methacholine (10−9−3 × 10−4 mol/l) were constructed in the presence and absence of each bronchodilator. Atrial natriuretic peptide, at a concentration of 10−6 mol/l, significantly attenuated contractions evoked by methacholine. In contrast, contractions evoked by endothelin-1 were enhanced by atrial natriuretic peptide at concentrations of 3 × 10−7 and 10−6 mol/l. Preincubation of salbutamol at a concentration of 10−6 mol/l significantly attenuated methacholine-induced contractions, but responses to endothelin-1 were not altered by preincubation of salbutamol at concentrations of 3 × 10−7, 10−6 and 3 × 10−6 mol/l. Sodium nitroprusside (10−6 mol/l) and isosorbide dinitrate (3 × 10−5 mol/l) did not alter responses evoked by subsequent addition of either endothelin-1 or methacholine. At a concentration of 10−4 mol/l, however, isosorbide dinitrate significantly attenuated endothelin-1-evoked contractions.
5. These results show that drugs which reverse agonist-induced tone in isolated bronchial rings may not necessarily protect against subsequent challenge with this agonist. This suggests that the pharmacology of relaxation may be dissimilar to that of protection.
‘Physiological’ Hyperinsulinaemia Increases Distal Artery Systolic Blood Pressure without Changing Proximal Blood Pressure
Authors: O'Callaghan Christopher James , Komersova Karla , Krum Henry , Louis William John 
Published: August 2015

1. Although epidemiological data links essential hypertension with insulin resistance, ‘physiological’ insulin concentrations have not had pressor effects in humans. Our previous studies suggested that hyperinsulinaemia might have effects on distal blood pressure which are not detected more proximally. Therefore, we used non-invasive techniques to determine the acute effects of insulin on proximal and distal blood pressure.
2. Blood pressure was measured in the finger (Finapres) and arm (Dinamap monitor) during a two-stage euglycaemic clamp. Values obtained during the insulin infusion were compared with a control infusion.
3. Plasma insulin concentrations were 7.0 ± 1.0 μ-units/ml at baseline and remained within the accepted post-prandial ‘physiological’ range during low- and high-dose insulin infusions (28.9 ± 2.1 and 101.7 ± 6.8 μ-units/ml respectively). From a baseline value of 130 ± 3 mmHg, finger systolic blood pressure rose by 9.9 ± 1.9 mmHg during the low-dose infusion (compared with 7.5 ± 2.7 mmHg in control, P &lt; 0.05) and by 21.9 ± 2.3 mmHg during the high-dose infusion (compared with 14.6 ± 3.1 mmHg in control, P &lt; 0.01). Compared with control, insulin did not have an additional effect on arm pressures.
4. Although finger systolic pressure was increased by hyperinsulinaemia, this occurred in the absence of a change in mean blood pressure or in arm pressures. These data therefore suggest that insulin augmented pulse wave reflection. This novel haemodynamic effect of insulin could contribute to the association of insulin resistance with essential hypertension.
Effects of Alcohol Intake on Organ Injuries in Normotensive and Hypertensive Human Subjects
Authors: Ishimitsu Toshihiko , Yoshida Kaori , Nakamura Miki , Tsukada Kohju , Yagi Shigeru , Ohrui Masami , Hisauchi Tohru , Matsuoka Hiroaki 
Published: August 2015

1. This cross-sectional study examined the influence of alcohol intake on organ injuries in normotensive and hypertensive subjects.
2. A total of 514 normotensive subjects and 302 never-treated hypertensive subjects were screened from 4557 men who entered the health check programme of our institute during the period 1990 to 1994. According to the daily alcohol consumption data reported by a self-administered questionnaire, the normotensive and hypertensive subjects were both classified into four categories; very light and non- (0–10 ml of ethanol), light (11–29 ml), moderate (30–58 ml) and heavy (≥59 ml) drinker groups. In these four pairs of groups, organ injuries in the heart, kidney and optic fundus were evaluated and serum lipids were measured.
3. Although the blood pressure levels were similar among the four groups of hypertensive subjects, the electrocardiographic findings of left ventricular hypertrophy were significantly more common among the moderate and heavy drinkers but not in the light drinkers compared with the very light and non-drinkers (very light and non-drinkers 25%, light drinkers 23%, moderate drinkers 38%, heavy drinkers 40%; P = 0.026). The alcohol intake increased the serum level of high-density lipoprotein cholesterol in a dose-dependent manner without changing the total cholesterol level; however, the serum γ-glutamyl transpeptidase and triacylglycerol levels were increased in the moderate and heavy drinkers. Urinary albumin excretion and fundoscopic lesions were not associated with the drinking habit in either the normotensive or hypertensive subjects.
4. These data suggest that habitual alcohol consumption exceeding 29 ml per day facilitates the development of left ventricular hypertrophy in hypertensive patients. Among the hypertensive subjects, light drinkers consuming 11 to 29 ml of ethanol daily showed preferable profiles in terms of organ injuries and risks of cardiovascular diseases.
Elevated Renal Endothelin-1 Clearance and mRNA Levels Associated with Albuminuria and Nephropathy in Non-Insulin-Dependent Diabetes Mellitus: Studies in Obese fa/fa Zucker Rats
Authors: Turner N. C. , Morgan P. J. , Haynes A. C. , Vidgeon-Hart M. , Toseland N. , Clapham J. C. 
Published: August 2015

1. The obese fa/fa Zucker rat is a genetic model of obesity and insulin resistance which develops a number of metabolic and endocrine features of non-insulin-dependent diabetes, including hypertension, proteinuria and glomerular sclerosis.
2. We have investigated the urinary excretion of the metabolites of thromboxane (thromboxane B2) and prostacyclin (6-keto prostaglandin F1α), and of endothelin and cyclic GMP as markers for changes in the balance of renal haemodynamic factors in the obese Zucker rat.
3. Obese fa/fa Zucker rats were hypertensive compared with their lean counterparts (161 ± 3 and 138 ± 3 mmHg respectively, P &lt; 0.01); obese animals were also markedly proteinuric (16.7 ± 6.7 versus 1.1 ± 0.1 mg/ml) and albuminuric (8.3 ± 2.9 versus 0.4 ± 0.25 mg/ml) and excreted less creatinine than lean animals (all P &lt; 0.01). Urinary excretion of endothelin was greater in obese rats (123 ± 24 versus 62 ± 10 pg/15 h, P &lt; 0.05) as was the level of pre-proendothelin mRNA, but excretion of cyclic GMP was depressed (12.5 ± 1.6 versus 27.2 ± 3.1 nmol/ 15 h, P &lt; 0.01). Histological examination of kidneys from obese animals showed evidence of focal glomerulosclerosis and cortical tubular damage.
4. These results show that increased urinary endothelin is associated with proteinuria and early stage nephropathy in this animal model of non-insulin-dependent diabetes mellitus. This finding, coupled with a decreased excretion of cyclic GMP, suggests that these increased renal vasoconstrictor/vasodilator forces might contribute to the renal functional changes in non-insulin-dependent diabetes mellitus.
Long- and Short-Term Blood Pressure and Rr-Interval Variability and Psychosomatic Distress in Chronic Fatigue Syndrome
Authors: Duprez Daniel A. , De Buyzere Marc L. , Drieghe Benny , Vanhaverbeke Friedl , Taes Youri , Michielsen Walter , Clement Denis L 
Published: August 2015

1. Chronic low blood pressure has been associated with fatigue and low mood. However, in the chronic fatigue syndrome (CFS) the blood pressure (BP) and heart rate profile and their variabilities have not been characterized as yet.
2. We performed office and 24 h ambulatory BP recordings in 38 subjects (age, 34.8 ± 8.0 years) who fulfilled the Holmes criteria for CFS and in 38 healthy control subjects (age 35.6 ± 10.5 years), as well as short-term beat-to-beat BP and RR-interval recordings for 10 min in supine and standing position, and calculated spectral indices.
3. In CFS office (123 ± 19/70 ± 12 mmHg) as well as 24-h, day- and night-time blood pressure values (116 ± 11.1/71 ± 11.1, 121 ± 9.2/77 ± 8.0 and 110 ± 10.5/65 ± 9.2 mmHg respectively) were within reference limits.
4. Heart rate was consistently higher (P &lt; 0.01) in CFS patients, based on both office (77 ± 12 compared with 68 ± 12 beats min−-1) and 24 h ambulatory recordings (77 ± 12 compared with 67 ± 15 beats min−-1).
5. In supine position, spectral indices of BP variability (total, low-frequency and high-frequency variances) were all significantly (P &lt; 0.01) lower in CFS. In standing position the differences disappeared. Analysis of RR-interval variability could not detect major alterations in autonomic function in CFS.
Applicability of New Techniques in the Assessment of Arterial Baroreflex Sensitivity in the Elderly: A Comparison with Established Pharmacological Methods
Authors: James Martin A. , Panerai Ronney B. , Potter John F. 
Published: August 2015

1. There has been considerable interest in techniques recently developed for the study of arterial baroreceptor—cardiac reflex sensitivity based on analysis of spontaneous baroreflex sequences and on spectral analysis. This study examined how these newer techniques agreed with the established pharmacological methods in elderly subjects.
2. In 20 elderly subjects [10 hypertensive (clinic blood pressure 180 ± 4/88 ± 2 mmHg) and 10 normotensive (clinic blood pressure 136 ± 3/73 ± 2 mmHg)], we assessed baroreflex sensitivity from spontaneous sequences of increasing and decreasing blood pressure and pulse interval and their mean, and from spectral analysis to derive α, the index of overall baroreflex gain. Pharmacological baroreflex sensitivity was derived from the blood pressure and pulse interval responses to depressor (sodium nitroprusside) and pressor (phenylephrine) stimuli, and their mean.
3. Baroreflex sensitivity was significantly lower in the hypertensive group by the pharmacological, sequence and spectral methods (all P &lt; 0.05).
4. There was acceptable agreement between pharmacological baroreflex sensitivity and sequences of the same direction, but with some systematic bias. There was also reasonable agreement between pharmacological and spectral baroreflex sensitivity and close agreement without bias between sequence and spectral methods.
5. The newer and established techniques demonstrate acceptable agreement in the elderly, albeit with some systematic bias. Pharmacological methods have enjoyed historical precedence but newer techniques give equivalent results, and are preferable in some circumstances. The newer techniques may be more descriptive of the spontaneous behaviour of the arterial baroreflex at rest rather than under artificially stimulated conditions.
Dynamics of Circulatory Adjustments to Head-Up Tilt and Tilt-Back in Healthy and Sympathetically Denervated Subjects
Authors: Wieling W. , Van Lieshout J. J. , Ten Harkel A. D. J. 
Published: August 2015

1. The initial circulatory adjustments induced by head-up tilt and tilt-back were investigated in six healthy subjects (aged 30–58 years) and six patients with orthostatic hypotension due to pure autonomic failure (aged 33–65 years).
2. Continuous responses of finger arterial pressure and heart rate were recorded by Finapres. A pulse contour algorithm applied to the arterial pressure waveform was used to compute stroke volume responses.
3. In the healthy subjects, head-up tilt induced gradual circulatory adjustments. After 1 min upright stroke volume and cardiac output had decreased by 39 ± 9% and 26 ± 10% respectively. Little change in mean blood pressure at heart level (+1 ± 7 mmHg) indicated that systemic vascular resistance had increased by 39 ± 24%. The gradual responses to head-up tilt contrasted with the pronounced and rapid circulatory responses upon tilt-back. After 2–3 s a rapid increase in stroke volume (from 62 ± 8% to 106 ± 10%) and cardiac output (from 81 ± 11% to 118 ± 20%) was observed with an overshoot of mean arterial pressure above supine control values of 16 ± 3 mmHg at 7 s. In the patients a progressive fall in blood pressure on head-up tilt was observed. After 1 min upright mean blood pressure had decreased by 59 ± 8 mmHg. No change in systemic vascular resistance and a larger decrease in stroke volume (60 ± 7%) and cardiac output (53 ± 8%) were found. On tilt-back a gradual recovery of blood pressure was observed.
4. In healthy humans upon head-up tilt neural compensatory mechanisms are very effective in maintaining arterial pressure at heart level. The gradual circulatory adjustments to head-up tilt in healthy subjects contrast with the pronounced and abrupt circulatory changes on tilt-back. In patients with a lack of neural circulatory reflex adjustments, gradual blood pressure decreases to head-up tilt and gradual increases to tilt-back are observed.
Fibroblasts from Post-Burn Hypertrophic Scar Tissue Synthesize Less Decorin than Normal Dermal Fibroblasts
Authors: Scott P. G. , Dodd C. M. , Ghahary A. , Shen Y.J. , Tredget E. E. 
Published: August 2015

1. Fibroblast cultures were established from biopsies of hypertrophic scar and normal dermis taken from nine patients recovering from second- and third-degree burns. The capacity of these fibroblasts to synthesize the small proteoglycan decorin was assessed by quantitative Western blot analysis of conditioned medium collected from confluent cultures. Levels of mRNA for decorin were assessed by quantitative Northern analysis. Since transforming growth factor-β1 is implicated in various fibrotic conditions, including post-burn hypertrophic scar, its effect on decorin synthesis by these paired fibroblast cell strains was assessed.
2. Production of decorin was lower in all cell strains of hypertrophic scar fibroblasts tested, compared with normal dermal fibroblasts cultured from the same patients (mean 49 ± 23%; P &lt; 0.001, n = 9). Levels of mRNA for decorin were also lower (mean 59 ± 28%; P &lt; 0.02, n = 7) but those for biglycan and versican were not significantly different. Four pairs of cell strains were examined at more than one passage and the differences in decorin protein were found to be phenotypically persistent. Treatment of confluent cultures with transforming growth factor-β1 for 3 days caused a reduction in both decorin protein and mRNA in all six strains of hypertrophic scar fibroblasts tested and in five of six strains of normal dermal fibroblasts. An increase in the length of the dermatan sulphate chain on decorin, a previously reported characteristic of this glycosaminoglycan in hypertrophic scar, was seen in all but two of the strains treated with transforming growth factor-β1. The depression of decorin synthesis by transforming growth factor-β1 was reversed on removal of the agent and passaging the fibroblasts.
3. The reduced capacity of fibroblasts in hypertrophic scar tissue to synthesize decorin may have implications for the development of the condition since this small proteoglycan is involved in tissue organization and may also play a role in modulating the activity in vivo of fibrogenic cytokines such as transforming growth factor-β1.