Upright Posture (upright + posture)

Distribution by Scientific Domains

Selected Abstracts

The Effect of Hemodialysis on Left Ventricular Outflow Tract Gradient

Pawel Petkow Dimitrow M.D.
Background: The aim of the study was to assess the effect of hemodialysis (HD) on left ventricular outflow tract gradient (LVOTG) measured both in supine and upright position (provocative maneuver to unload LV cavity by rapid preload reduction). Supine/standing echocardiography was performed immediately before and immediately after HD. For additional verification of the hypothesis about preload-dependence of LVOTG, the echocardiograms after long (2-day delay HD due to weekend) versus short (usual 1-day) pause between HDs were compared. Methods: Forty-one patients on chronic HD (mean age 44 ± 11 years) were examined using a portable hand-carried echocardiograph. In accordance with the prestudy assumption the ultrafiltration volume was significantly greater during HD after a long pause in comparison to HD after a short pause (3707 ± 2826 mL vs. 2665 ± 1152 mL P < 0.05). Results: After a long pause, the mean value of LVOTG at the pre-HD was mildly increased in the supine position and remained at a similar level in the upright position (13.1 ± 6.1 vs. 13.6 ± 9.1 mmHg). Mean LVOTG at the post-HD in the supine position was similar to pre-HD, however the orthostatic stress test induced a significant increase of LVOTG (13.9 ± 15.2 vs. 18.2 ± 19.9 mmHg P < 0.05). After a short pause at the pre-HD the LVOTG in the supine position and after the orthostatic provocation was very similar to measurements after long pause (13.3 ± 9.1 vs. 13.3 ± 10.8 mmHg). At the post-HD the mean value of LVOTG increased during upright posture but the differences were of borderline significance (13.2 ± 6.6 vs. 17.9 ± 18.6 mmHg P = 0.052). Conclusions: HD predisposed to standing-provoked LVOTG especially when a long pause (2 days) between HDs induced a greater weight gain and subsequently a larger volume of ultrafiltration was needed to reduce hypervolemia. (Echocardiography 2010;27:603-607) [source]

Proximal pulmonary artery blood flow characteristics in healthy subjects measured in an upright posture using MRI: The effects of exercise and age,

Christopher P. Cheng PhD
Abstract Purpose To use MRI to quantify blood flow conditions in the proximal pulmonary arteries of healthy children and adults at rest and during exercise in an upright posture. Materials and Methods Cine phase-contrast MRI was used to calculate mean flow and reverse flow index (RFI) in the main (MPA), right (RPA), and left (LPA) pulmonary arteries in healthy children and adults in an open-MRI magnet equipped with an upright MRI-compatible ergometer. Results From rest to exercise (150% resting heart rate), blood flow (liters/minute/m2) increased in the RPA (1.4 ± 0.3 vs. 2.5 ± 0.4; P < 0.001), LPA (1.1 ± 0.3 vs. 2.2 ± 0.6; P < 0.001), and MPA (2.7 ± 0.5 vs. 4.9 ± 0.5; P < 0.001). RFI decreased in the LPA (0.040 ± 0.030 vs. 0.017 ± 0.018; P < 0.02) and MPA (0.025 ± 0.024 vs. 0.008 ± 0.007; P < 0.03). Adults experienced greater retrograde flow in the MPA than the children (0.042 ± 0.029 vs. 0.014 ± 0.012; P < 0.02). Conclusion It appears that at both rest and during exercise, in children and adults alike, RPA/LPA mean blood flow distribution is predominantly determined by distal vascular resistance, while retrograde flow is affected by proximal pulmonary bifurcation geometry. J. Magn. Reson. Imaging 2005;21:752,758. © 2005 Wiley-Liss, Inc. [source]

Paul Blocq and (psychogenic) astasia abasia

Michael S. Okun MD
Abstract The Greek term astasia,abasia literally translates to mean inability to stand and to walk. Although today we would classify the syndrome as a conversion disorder, it was considered a separate disease by Paul Blocq (1860,1896), who described this phenomenon as the inability to maintain an upright posture, despite normal function of the legs in the bed. Paul Blocq's original 1888 articles on astasia abasia were read, partly translated from French to English, and the cases were summarized. A review of a selection of the literature following Blocq's description on astasia abasia was performed. Present day literature was consulted as well. Blocq reviewed what was known about astasia abasia in two papers. Although he was the first to use the combined term astasia abasia, he referred to similar descriptions of Charcot, Richer, Mitchell, Jaccoud, Roméi, and Erlenmeyer. Blocq's contribution was in compiling the experiences and observations of preeminent 19th century neurologists. He recognized that paralysis, jumping, fits, tremor, and bizarre behavior could all be associated with the syndrome. He distinguished the disorder from hysteria. Moreover, he presented a formal delineation of the gait disorder and provided a pathophysiologic concept. Prognosis was considered favorable. Paul Blocq directed attention to psychogenic gait disorders by publishing a small case series on astasia abasia. Today, these case descriptions would be likely considered cases of conversion or psychogenic gait disorder, with or without other conversion/psychogenic movement disorders. © 2007 Movement Disorder Society [source]

The effects of Masai Barefoot Technology, footwear on posture: an experimental designed study

Paul New
Introduction.,This study was approved by the University of Southampton Ethics Committee. The aim of the study was to assess the anatomical changes to upright posture that occur in the sagittal plane as a result of wearing Masai Barefoot Technology (MBT) footwear during standing and walking. MBT claims that its innovative unstable shoes promote a more upright posture in which musculature is strengthened and joint wear reduced (Amann and Amann, 2004). This could be helpful in the management and prevention of conditions such as osteoarthritis and back pain. Method.,Twelve students (six male and six female), aged between 18 and 40 years, at the University of Southampton participated in the study. Participants attended one session at a biomechanics laboratory. The kinematics of posture while wearing MBT shoes during standing and gait were examined, using a two-dimensional motion analysis system, and compared to a control shoe. Statistical significance was tested by use of a paired t -test and a Wilcoxon signed-ranks test. Results.,Students standing in MBT footwear demonstrated a statistically significant increase in plantar flexion at the ankle joint (p = 0.025; mean flexion 3.02°; 95% confidence interval [95% CI] ,5.6 to ,0.4). Walking in MBT shoes showed a decrease in trunk flexion (p = 0.007; mean flexion 1.44°; 95% CI ,2.4 to ,0.4) and a reduction in anterior tilt of the pelvis (p = 0.003; mean tilt 3.20°; 95% CI ,5.06 to ,1.35) at heel strike. At toe-off a significant reduction in anterior pelvic tilt (p = 0.035; mean tilt 2.35°; 95% CI) was found in the MBT shoes. There was no significant difference found between the two shoe conditions at mid-stance, pelvic tilt (p = 0.53; mean tilt 1.83 degrees) trunk flexion (p = 0.05; mean flexion 0.95 deg). Conclusion.,MBT footwear changes certain characteristics of posture in quiet standing and walking. These findings could have positive implications for the management of conditions such as osteoarthritis and back pain; however, further research is needed. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Morphology and function of the lumbar spine of the Kebara 2 Neandertal

Ella Been
Abstract The morphology of the lumbar spine is crucial for upright posture and bipedal walking in hominids. The excellent preservation of the lumbar spine of Kebara 2 provides us a rare opportunity to observe a complete spine and explore its functionally relevant morphology. The lumbar spine of Kebara 2 is analyzed and compared with the lumbar spines of modern humans and late Pleistocene hominids. Although no size differences between the vertebral bodies and pedicles of Kebara 2 and modern humans are found, significant differences in the size and orientation of the transverse processes (L1 -L4), and the laminae (L5, S1) are demonstrated. The similarity in the size of the vertebral bodies and pedicles of Kebara 2 and modern humans suggests similarity in axial load transmission along the lumbar spine. The laterally projected (L2 -L4) and the cranially oriented (L1, L3) transverse processes of Kebara 2 show an advantage for lateral flexion of the lumbar spine compared with modern humans. The characteristic morphology of the lumbar spine of Kebara 2 might be related to the wide span of its pelvic bones. Am J Phys Anthropol 142:549,557, 2010. © 2010 Wiley-Liss, Inc. [source]

Vasomotor sympathetic neural control is maintained during sustained upright posture in humans

Qi Fu
Vasomotor sympathetic activity plays an important role in arterial pressure maintenance via the baroreflex during acute orthostasis in humans. If orthostasis is prolonged, blood pressure may be supported additionally by humoral factors with a possible reduction in sympathetic baroreflex sensitivity. We tested the hypothesis that baroreflex control of muscle sympathetic nerve activity (MSNA) decreases during prolonged upright posture. MSNA and haemodynamics were measured supine and during 45 min 60 deg upright tilt in 13 healthy individuals. Sympathetic baroreflex sensitivity was quantified using the slope of the linear correlation between MSNA and diastolic pressure during spontaneous breathing. It was further assessed as the relationship between MSNA and stroke volume, with stroke volume derived from cardiac output (C2H2 rebreathing) and heart rate. Total peripheral resistance was calculated from mean arterial pressure and cardiac output. We found that MSNA increased from supine to upright (17 ± 8 (s.d.) versus 38 ± 12 bursts min,1; P < 0.01), and continued to increase to a smaller degree during sustained tilt (39 ± 11, 41 ± 12, 43 ± 13 and 46 ± 15 bursts min,1 after 10, 20, 30 and 45 min of tilt; between treatments P < 0.01). Sympathetic baroreflex sensitivity increased from supine to upright (,292 ± 180 versus,718 ± 362 units beat,1 mmHg,1; P < 0.01), but remained unchanged as tilting continued (,611 ± 342 and ,521 ± 221 units beat,1 mmHg,1 after 20 and 45 min of tilt; P= 0.49). For each subject, changes in MSNA were associated with changes in stroke volume (r= 0.88 ± 0.13, P < 0.05), while total peripheral resistance was related to MSNA during 45 min upright tilt (r= 0.82 ± 0.15, P < 0.05). These results suggest that the vasoconstriction initiated by sympathetic adrenergic nerves is maintained by ongoing sympathetic activation during sustained (i.e. 45 min) orthostasis without obvious changes in vasomotor sympathetic neural control. [source]

Different vasodilator responses of human arms and legs

Sean C. Newcomer
Forearm vascular responses to intra-arterial infusions of endothelium-dependent and -independent vasodilators have been thoroughly characterized in humans. While the forearm is a well-established experimental model for studying human vascular function, it is of limited consequence to systemic cardiovascular control owing to its small muscle mass and blood flow requirements. In the present study we determined whether these responses could be generalized to the leg. Based upon blood pressure differences between the leg and arm during upright posture, we hypothesized that the responsiveness to endothelium-dependent vasodilators would be greater in the forearm than the leg. Brachial and femoral artery blood flow (Q, ultrasound Doppler) at rest and during intra-arterial infusions of endothelium-dependent (acetylcholine and substance P) and -independent (sodium nitroprusside) vasodilators were measured in eight healthy men (22,27 years old). Resting blood flows in the forearm before infusion of acetylcholine, substance P or sodium nitroprusside were 25 ± 4, 30 ± 7 and 29 ± 5 ml min,1, respectively, and in the leg were 370 ± 32, 409 ± 62 and 330 ± 30 ml min,1, respectively. At the highest infusion rate of acetylcholine (16 ,g (100 ml tissue),1 min,1) there was a greater (P < 0.05) increase in Q to the forearm (1864 ± 476%) than to the leg (569 ± 86%). Similarly, at the highest infusion rate of substance P (125 pg (100 ml tissue),1 min,1) there was a greater (P < 0.05) increase in Q to the forearm (911 ± 286%) than to the leg (243 ± 58%). The responses to sodium nitroprusside (1 ,g (100 ml tissue),1 min,1) were also greater (P < 0.05) in the forearm (925 ± 164%) than in the leg (326 ± 65%). These data indicate that vascular responses to both endothelium-dependent and -independent vasodilator agents are blunted in the leg compared to the forearm. [source]

Commercial Hospital Discharge Packs for Breastfeeding Women

BIRTH, Issue 1 2001
J. K. Gupta
A substantive amendment to this systematic review was last made on 23 March 1999. Cochrane reviews are regularly checked and updated if necessary. ABSTRACT Background: For centuries, there has been controversy around whether being upright (sitting, birthing stools, chairs, squatting) or lying down has advantages for women delivering their babies. Objectives: The objective of this review was to assess the benefits and risks of the use of different positions during the second stage of labour (i.e., from full dilatation of the cervix). Search strategy: Relevant trials are identified from the register of trials maintained by the Cochrane Pregnancy and Childbirth Group, and from the Cochrane Controlled Trials Register. Selection criteria: Trials were included which compared various positions assumed by pregnant women during the second stage of labour. Randomised and quasi-randomised trials with appropriate follow-up were included. Data collection and analysis: Trials were independently assessed for inclusion, and data extracted by the two authors. Disagreements would have been resolved by consensus with an editor. Meta-analysis of data is performed using the RevMan software. Main results: Results should be interpreted with caution as the methodological quality of the 18 trials was variable. Use of any upright or lateral position, compared with supine or lithotomy positions, was associated with: 1Reduced duration of second stage of labour (12 trials,mean 5.4 minutes, 95% confidence interval (CI) 3.9,6.9 minutes). This was largely due to a considerable reduction in women allocated to use of the birth cushion. 2A small reduction in assisted deliveries (17 trials,odds ratio (OR) 0.82, 95% CI 0.69,0.98). 3A reduction in episiotomies (11 trials,OR 0.73, 95% CI 0.64,0.84). 4A smaller increase in second degree perineal tears (10 trials,OR 1.30, 95% CI 1.09,1.54). 5Increased estimated risk of blood loss > 500ml (10 trials,OR 1.76, 95% CI 1.34,3.32). 6Reduced reporting of severe pain during second stage of labour (1 trial,OR 0.59, 95% CI 0.41,0.83). 7Fewer abnormal fetal heart rate patterns (1 trial,OR 0.31, 95% CI 0.11,0.91). Reviewers' conclusions: The tentative findings of this review suggest several possible benefits for upright posture, with the possibility of increased risk of blood loss > 500 mL. Women should be encouraged to give birth in the position they find most comfortable. Until such time the benefits and risks of various delivery positions are estimated with greater certainty when methodologically stringent trials data are available, then women should be allowed to make informed choices about the birth positions in which they might wish to assume for delivery of their babies. Citation: Gupta JK, Nikodem VC. Women's position during second stage of labour (Cochrane Review). In: The Cochrane Library, Issue 4, 2000. Oxford: Update Software. [source]

Decrease in heart rate variability with overtraining: assessment by the Poincaré plot analysis

Laurent Mourot
Summary Numerous symptoms have been associated with the overtraining syndrome (OT), including changes in autonomic function. Heart rate variability (HRV) provides non-invasive data about the autonomic regulation of heart rate in real-life conditions. The aims of the study were to: (i) characterize the HRV profile of seven athletes (OA) diagnosed as suffering of OT, compared with eight healthy sedentary (C) and eight trained (T) subjects during supine rest and 60° upright, and (ii) compare the traditional time- and frequency-domain analysis assessment of HRV with the non-linear Poincaré plot analysis. In the latter each R-R interval is plotted as a function of the previous one, and the standard deviations of the instantaneous (SD1) and long-term R-R interval variability are calculated. Total power was higher in T than in C and OA both in supine (1158 ± 1137, 6092 ± 3554 and 2970 ± 2947 ms2 for C, T and OA, respectively) and in upright (640 ± 499, 1814 ± 806 and 1092 ± 712 ms2 for C, T and OA, respectively; P<0·05) positions. In supine position, indicators of parasympathetic activity to the sinus node were higher in T compared with C and OA (high-frequency power: 419·1 ± 381·2, 1105·3 ± 781·4 and 463·7 ± 715·8 ms2 for C, T and OA, respectively; P<0·05; SD1: 29·5 ± 18·5, 75·2 ± 17·2 and 37·6 ± 27·5 for C, T and OA, respectively; P<0·05). OA had a marked predominance of sympathetic activity regardless of the position (LF/HF were 0·47 ± 0·35, 0·47 ± 0·50 and 3·96 ± 5·71 in supine position for C, T and OA, respectively, and 2·09 ± 2·17, 7·22 ± 6·82 and 12·04 ± 10·36 in upright position for C, T and OA, respectively). The changes in HRV indexes induced by the upright posture were greater in T than in OA. The shape of the Poincaré plots allowed the distinction between the three groups, with wide and narrow shapes in T and OA, respectively, compared with C. As Poincaré plot parameters are easy to compute and associated with the ,width' of the scatter gram, they corroborate the traditional time- and frequency-domain analysis. We suggest that they could be used to indicate fatigue and/or prevent OT. [source]

Play fighting in androgen-insensitive tfm rats: Evidence that androgen receptors are necessary for the development of adult playful attack and defense

Evelyn F. Field
Abstract The frequency of playful attack and the style of playful defense, are modifiable by gonadal steroids and change after puberty in male and female rats. The present study examined the play behavior exhibited by testicular feminized mutation (tfm) -affected males, who are insensitive to androgens but can bind estrogens aromatized from androgens, to determine the relative contributions of androgens and estrogens to the age-related changes in play behavior. tfm males did not exhibit a decrease in playful attack with age and were more likely to maintain the use of complete rotations, a juvenile form of playful defense, into adulthood. tfm males did however, show age related changes in the use of partial rotations and upright postures, two other forms of playful defense, that were similar to normal males. These data suggest that the development of play fighting and defense in males is dependent on both androgen- and estrogen-receptor-mediated effects. © 2006 Wiley Periodicals, Inc. Dev Psyshobiol 48: 111,120, 2006. [source]

Ambulation in labour and delivery mode: a randomised controlled trial of high-dose vs mobile epidural analgesia,

ANAESTHESIA, Issue 3 2009
M. J. A. Wilson
Summary Compared to high-dose epidurals where mobility is impossible, mobile epidurals have been shown to reduce instrumental vaginal delivery rates. The mechanism for this benefit may depend on women walking or adopting upright postures during labour. We investigated maternal motor power and ambulation of 1052 primparous women randomised to high-dose epidural (Control), Combined Spinal Epidural (CSE) or Low-Dose Infusion (LDI) as a pre-specified, secondary outcome of the Comparative Obstetric Mobile Epidural Trial. Modified Bromage power scores and the level of mobility a woman actually achieved were recorded each hour after epidural placement during first and second stage, until delivery. Relative to control, significantly more women maintained normal leg power throughout labour in both mobile groups and significantly more women with CSE maintained superior leg power for longer than with LDI. Observational analysis did not demonstrate an association between the level of ambulation a woman actually achieved after epidural placement and delivery mode. [source]