Central cardiovascular pressures during graded water immersion in humans

1993 ◽  
Vol 75 (2) ◽  
pp. 581-585 ◽  
Author(s):  
A. Gabrielsen ◽  
L. B. Johansen ◽  
P. Norsk
Keyword(s):  
Linear Correlation ◽  
Water Immersion ◽  
Venous Pressure ◽  
Esophageal Pressure ◽  
Water Levels ◽  
Xiphoid Process ◽  
Positive Linear Correlation ◽  
Cardiac Filling ◽  
Normal Males ◽  
Fourth Intercostal Space

Thermoneutral (34.9 degrees C) water immersion (WI) was conducted with 12 upright seated normal males at four consecutive water levels (5–10 min each): knee (reference), xiphoid process, fourth intercostal space, and sternoclavicular notch. Thereafter, water was let out of the tank and the experiment was repeated from the neck to the knees at the same levels. Arterial pulse pressure (PP), central venous pressure (CVP), and transmural CVP (TCVP = CVP - esophageal pressure; n = 4) gradually increased with increasing water levels (P < 0.05). Heart rate (HR) decreased at WI to the xiphoid process (P < 0.05) and thereafter remained at this level, whereas mean arterial pressure remained unchanged. There was a closer linear correlation between HR and PP (r = -0.35, P < 0.01) than between HR and CVP (r = -0.13, P > 0.05). Furthermore, there was a significant positive linear correlation between CVP and TCVP (r = 0.83, P < 0.01). We conclude that WI in humans induces an increase in cardiac filling pressures with an increase in PP and a consequent decrease in HR. Furthermore, changes in CVP accurately reflect changes in cardiac distension (TCVP) during WI.

Atrial distension in humans during microgravity induced by parabolic flights

1997 ◽  
Vol 83 (6) ◽  
pp. 1862-1866 ◽  
Author(s):  
Regitze Videbaek ◽  
Peter Norsk
Keyword(s):  
Central Venous Pressure ◽  
Left Atrium ◽  
Supine Position ◽  
Left Atrial ◽  
Venous Pressure ◽  
Esophageal Pressure ◽  
Central Venous ◽  
Parabolic Flights ◽  
Left Atrial Diameter ◽  
Cardiac Filling

Videbaek, Regitze, and Peter Norsk. Atrial distension in humans during microgravity induced by parabolic flights. J. Appl. Physiol. 83(6): 1862–1866, 1997.—The hypothesis was tested that human cardiac filling pressures increase and the left atrium is distended during 20-s periods of microgravity (μG) created by parabolic flights, compared with values of the 1-G supine position. Left atrial diameter ( n = 8, echocardiography) increased significantly during μG from 26.8 ± 1.2 to 30.4 ± 0.7 mm ( P < 0.05). Simultaneously, central venous pressure (CVP; n = 6, transducer-tipped catheter) decreased from 5.8 ± 1.5 to 4.5 ± 1.1 mmHg ( P < 0.05), and esophageal pressure (EP; n = 6) decreased from 1.5 ± 1.6 to −4.1 ± 1.7 mmHg ( P < 0.05). Thus transmural CVP (TCVP = CVP − EP; n = 4) increased during μG from 6.1 ± 3.2 to 10.4 ± 2.7 mmHg ( P < 0.05). It is concluded that short periods of μG during parabolic flights induce an increase in TCVP and left atrial diameter in humans, compared with the results obtained in the 1-G horizontal supine position, despite a decrease in CVP.

Arginine vasopressin, circulation, and kidney during graded water immersion in humans

1986 ◽  
Vol 61 (2) ◽  
pp. 565-574 ◽  
Author(s):  
P. Norsk ◽  
F. Bonde-Petersen ◽  
J. Warberg
Keyword(s):  
Arginine Vasopressin ◽  
Water Immersion ◽  
Venous Pressure ◽  
Free Water ◽  
Systolic Arterial Pressure ◽  
Free Water Clearance ◽  
Plasma Arginine ◽  
Normal Males ◽  
Solute Excretion ◽  
Rebreathing Method

Ten normal males rested sitting upright at an air temperature of 28 degrees C for 5.5 h (control, C) and underwent 4 h of graded water immersion (WI) to the umbilicus (UI), to the chest (CI), and to the neck (NI), respectively (water temperature = 34.5 degrees C), on different experimental days. Plasma arginine vasopressin (PAVP) was suppressed during WI compared with C and maximally so during NI. However, there was no change in PAVP comparing CI with UI even though central venous pressure (CVP) increased. CVP increased during CI and NI compared with C but was unchanged during UI, whereas cardiac output (rebreathing method), stroke volume, and plasma volume increased to approximately the same level during all three steps of WI compared with C. Heart rate and total peripheral vascular resistance decreased during UI, CI, and NI. Systolic arterial pressure (SAP) and pulse pressure (PP) were increased gradually from prestudy related to the degree of WI. Also diuresis, natriuresis, kaliuresis, osmotic excretion, and clearance were increased gradually compared with C, whereas free water clearance (CH2O) gradually decreased. There were weak negative but statistically significant correlations between PAVP and CVP and between changes in PAVP from prestudy and corresponding changes in SAP and PP. Furthermore, a statistically significant and negative correlation between CH2O and natriuresis could be established. We conclude that graded immersion gradually increases central blood volume and decreases PAVP. However, not only cardiopulmonary mechanoreceptors but also arterial baroreceptors may play a role in AVP suppression during WI in humans. In hydropenic subjects the suppression of PAVP during WI is apparently not effective in counteracting the decrease in CH2O induced by increased solute excretion.

Non-metamict uranoan pyrochlore and uranpyrochlore from tuff near Ndale, Fort Portal area, Uganda

1989 ◽  
Vol 53 (370) ◽  
pp. 257-262 ◽  
Author(s):  
D. D. Hogarth ◽  
J. E. T. Horne
Keyword(s):  
Cell Size ◽  
Linear Correlation ◽  
Metamorphic Rocks ◽  
Portal Area ◽  
Geological Age ◽  
Unit Cells ◽  
Positive Linear Correlation ◽  
Crystalline Nature ◽  
Linear Correlations

AbstractA thin (100 m) cover of flat-lying, Recent, calcite-rich tuff at Ndale near Fort Portal, Uganda, unconformably overlies steeply dipping Precambrian metamorphic rocks. It is locally radioactive owing to uranium-rich pyrochlore minerals and lesser amounts of zircon, monazite, titanite, and an unidentified thorium phosphate. In one concentrate, four grains of uranpyrochlore and one grain of uranoan pyrochlore showed a positive linear correlation of Ti with U, and negative linear correlations of Ti with Na, F and Sr. Ta remained high and relatively constant [11 anal., ave. 14.5 (0.6)% Ta2O5]. In the same concentrate the composition of a separate grain of uranoan pyrochlore did not plot on these lines and Ta was comparatively low [2 anal., ave. 4.5 (0.3)% Ta2O5]. The data suggest two separate paths of differentiation. However, zoned grains were not observed. Unit cells were cubic with a = 10.351 ± 0.002 Å for a grain with 12.9% UO2tot and 10.333 ± 0.002 Å for a grain with 26.6% UO2tot. On heating in air the cell size decreased, possibly due to oxidation of U4+. The crystalline nature of these minerals can be attributed to a very young (4000–5000 yr) geological age.

scholarly journals Effect of Ultrasonic Treatment on Radon Exhalation from Porous Media: An Experimental Case Study

2018 ◽  
Vol 10 (9) ◽  
pp. 3005
Author(s):  
Ling-feng Xie ◽  
Shu-liang Zou ◽  
Xiang-yang Li ◽  
Chang-shou Hong ◽  
Hong Wang ◽  
...  
Keyword(s):  
Porous Media ◽  
Moisture Content ◽  
Ultrasonic Wave ◽  
Linear Correlation ◽  
Experimental Results ◽  
Radon Exhalation Rate ◽  
Exhalation Rate ◽  
Radon Exhalation ◽  
Experimental Apparatus ◽  
Positive Linear Correlation

Radon is internationally recognized as one of the seven seismic precursors. A self-assembly ultrasonic generator and experimental apparatus for radon measurement were utilized to explore the radon exhalation regularities of water-bearing porous media under different ultrasonic intensities. The experimental results showed that there was a coupling relationship among radon exhalation rate, moisture content, and ultrasonic frequency. With the increase of the frequency of the ultrasonic wave, its effect on the promotion of radon exhalation rate was found to be a more obviously positive linear correlation. The radon exhalation rate, which could climb to a maximum value of 0.179 Bq·m−2·s−1 in a naturally air-dried sample, increased at first and then decreased along with increased moisture content. Moreover, this study found that the ultrasonic wave had the most remarkable promoting effects on the radon exhalation rate of porous media with high moisture content, and there is a positive linear correlation between the growth rate of the radon exhalation rate and moisture content. The experimental results could provide a beneficial reference for the continual monitoring of radon in a seismically active belt and an explanation of radon anomalies; however, the proposed experimental model was simplified, so further insights are strictly required for a reliable correlation with the real monitoring of radon in a seismically active belt.

Contribution of abdomen and legs to central blood volume expansion in humans during immersion

1997 ◽  
Vol 83 (3) ◽  
pp. 695-699 ◽  
Author(s):  
Lars Bo Johansen ◽  
Thomas Ulrik Skram Jensen ◽  
Bettina Pump ◽  
Peter Norsk
Keyword(s):  
Blood Volume ◽  
Volume Expansion ◽  
Protein Concentration ◽  
Water Immersion ◽  
Venous Pressure ◽  
Cuff Inflation ◽  
Central Blood Volume ◽  
Central Venous ◽  
Plasma Protein Concentration ◽  
Blood Volume Expansion

Johansen, Lars Bo, Thomas Ulrik Skram Jensen, Bettina Pump, and Peter Norsk. Contribution of abdomen and legs to central blood volume expansion in humans during immersion. J. Appl. Physiol. 83(3): 695–699, 1997.—The hypothesis was tested that the abdominal area constitutes an important reservoir for central blood volume expansion (CBVE) during water immersion in humans. Six men underwent 1) water immersion for 30 min (WI), 2) water immersion for 30 min with thigh cuff inflation (250 mmHg) during initial 15 min to exclude legs from contributing to CBVE (WI+Occl), and 3) a seated nonimmersed control with 15 min of thigh cuff inflation (Occl). Plasma protein concentration and hematocrit decreased from 68 ± 1 to 64 ± 1 g/l and from 46.7 ± 0.3 to 45.5 ± 0.4% ( P < 0.05), respectively, during WI but were unchanged during WI+Occl. Left atrial diameter increased from 27 ± 2 to 36 ± 1 mm ( P < 0.05) during WI and increased similarly during WI+Occl from 27 ± 2 to 35 ± 1 mm ( P < 0.05). Central venous pressure increased from −3.7 ± 1.0 to 10.4 ± 0.8 mmHg during WI ( P < 0.05) but only increased to 7.0 ± 0.8 mmHg during WI+Occl ( P < 0.05). In conclusion, the dilution of blood induced by WI to the neck is caused by fluid from the legs, whereas the CBVE is caused mainly by blood from the abdomen.

scholarly journals Morphometric analysis of the sella turcica in Northeastern Brazil

2021 ◽  
Author(s):  
Pablo Mariz de Oliveira ◽  
Amanda do Nascimento Oliveira e Carneiro ◽  
Fábio Antônio Serra de Lima Júnior ◽  
Daniel Dantas da Silva ◽  
Leticia Leite Cavalcante ◽  
...  
Keyword(s):  
Pituitary Gland ◽  
Linear Correlation ◽  
Sella Turcica ◽  
Northeastern Brazil ◽  
Surgical Approaches ◽  
Linear Measurements ◽  
Positive Linear Correlation ◽  
Skull Measurements ◽  
And Gender ◽  
Human Skulls

Introduction: The sella turcica is a structure of the median region of the sphenoid bone. Variations in its morphology are relevant as it is a region subjected to several surgical procedures, mainly related to the pituitary gland. Objective: To analyze the morphology of the sella turcica and its sexual dimorphism in Northeastern Brazil. Methods: Fifteen human skulls from the Federal University of Paraíba (UFPB) were used. The qualitative analysis was performed by classifying the shape of the sella turcica into three types: U, J and flattened. Morphometric data was collected and statistically analyzed to evaluate the relationship between sella morphometry and gender, and between sella and skull measurements. Values of p< 0.05) in the sella turcica length (STL) and skull length (SL), with male skulls being larger in both cases. The other linear measurements didn’t show differences between the sexes (p>0.05). There was a positive linear correlation between STL and SL, and a negative linear correlation between sella turcica width (STW) and sella turcica height (STH) and between STH and bitemporal width (BTW). Conclusion: The results point to important differences in the morphometric parameters evaluated with original findings for this population. Knowledge of the morphology of the sella is essential to plan safer surgical approaches in the pituitary gland or related anatomical structures.

scholarly journals A Relationship between Resilience and Psychological Preparedness for Disaster among Airlangga University Health Faculty Students

2020 ◽  
Vol 202 ◽  
pp. 12025
Author(s):  
Listyati Setyo Palupi ◽  
Muhammad Noor Rahman Himawan
Keyword(s):  
Disaster Management ◽  
Linear Correlation ◽  
Survey Method ◽  
Correlation Score ◽  
Resilience Scale ◽  
The People ◽  
Coefficient Corrélation ◽  
Positive Linear Correlation ◽  
Prone Area ◽  
National Disaster

National Disaster Management Agency of Indonesia recorded 3,406 disasters events during in Indonesia reached. Research suggest that people who lived in the disasters prone area such as need to be well prepared both physically and psychologically in order to reduce the risk of disaster and ensure that the people are resilience. One of disasters prone area in east part of Java island is East Java Province. In East Java total of disasters occurred are 1537 case. Therefore, it is important to identify their psychological preparedness and resilience in this region. Thus, this study aims to determine whether there is a correlation between resilience with psychological preparedness for disaster. This research was conducted among Airlangga University Health Faculty Students in Surabaya, East Java. This research uses a quantitative approach with a survey method. The scale used are Brief Resilience Scale and Psychological Preparedness for Potential Disasters Scale. The results obtained from this study are that there is a positive linear correlation between resilience and psychological preparedness for disaster with 0.338 coefficient correlation score. That means if the level of resilience is high, the level of psychological preparedness for disaster will also be high. Vice versa.

Muscle sympathetic nerve responses to dynamic one-legged exercise: effect of body posture

1993 ◽  
Vol 264 (1) ◽  
pp. H1-H7 ◽  
Author(s):  
C. A. Ray ◽  
R. F. Rea ◽  
M. P. Clary ◽  
A. L. Mark
Keyword(s):  
Sympathetic Nerve ◽  
Venous Return ◽  
Muscle Sympathetic Nerve Activity ◽  
Venous Pressure ◽  
Arm Exercise ◽  
Exercise Effect ◽  
Leg Exercise ◽  
Cardiac Filling ◽  
Cardiopulmonary Baroreceptors

Previous studies examining muscle sympathetic nerve activity (MSNA) during dynamic exercise have focused on upper extremity exercise. The present study was undertaken to investigate 1) MSNA responses to dynamic one-legged knee extensions (DLE) and 2) the role of the cardiopulmonary baroreflexes in the modulation of MSNA responses to DLE. MSNA was measured during 4 min of DLE at 20 (n = 10) and 30 W (n = 9) and during 3 min of DLE at 40 W (n = 9). DLE was performed in the upright (sitting) position and MSNA was recorded in the contralateral leg (peroneal nerve). DLE elicited significant increases in mean arterial pressure (MAP) and heart rate (HR; P < 0.05). In contrast to previous studies using dynamic arm exercise, MSNA (bursts/min) decreased by 25% (P < 0.05) during the first minute of DLE from resting control and remained suppressed during the remaining 3 min of DLE at 20 and 30 W. During the first minute of DLE at 40 W, MSNA (bursts/min) decreased by 18% (P < 0.05), but returned to control levels during the last minute of exercise. Because dynamic leg exercise in the upright position increases venous return, we postulated that upright DLE might increase cardiac filling pressures and stimulate the cardiopulmonary baroreceptors resulting in suppression of MSNA. To investigate this possibility, we measured MSNA and central venous pressure (CVP) during 4 min of both supine and upright DLE at 30 W. MAP, HR, and CVP increased and MSNA decreased from 30 +/- 3 to 22 +/- 3 bursts/min (mean exercise value; P < 0.05) during upright DLE.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals In Vitro and In Vivo Digestibility of Native Maize Starch Granules Varying in Amylose Contents

2007 ◽  
Vol 90 (6) ◽  
pp. 1628-1634 ◽  
Author(s):  
Tatsuya Morita ◽  
Yusuke Ito ◽  
Ian Lewis Brown ◽  
Ryuichi Ando ◽  
Shuhachi Kiriyama
Keyword(s):  
Surface Area ◽  
Linear Correlation ◽  
Resistant Starch ◽  
Amylose Content ◽  
Starch Granules ◽  
Gelatinization Temperature ◽  
Maize Starch ◽  
Positive Linear Correlation

Abstract Digestibility of maize starch granules with different amylose content (AL-0, 22, 54, 68, 80, or 90) was investigated. Measurement of the in vivo resistant starch (RS) content of the starches was performed using surgically prepared ileorectostomized rats. The rats were fed a purified diet containing one of the starches at 652.5 g/kg diet. The in vivo RS content was determined based on the fecal starch excretion. The dietary fiber (DF) value increased as a function of the amylose content in the starch and showed a positive linear correlation with the gelatinization temperature of the granules. In contrast, the in vitro RS content was likely to depend on both the surface area and amylose contents of the starch granules. The maximum in vitro RS content was obtained with AL-68 (54.4). In vivo RS content showed a significant correlation with the amount of in vitro RS but not in respect to the DF detected. The in vivo RS content of AL-68 (43.4) was higher than that found in AL-90 (37.8). A profound gap was observed for AL-54 between the amount of DF (6.4) and RS (in vitro = 46.6 and in vivo = 40.9) present. The results suggest that both in vitro and in vivo digestibility of maize starch is affected by the amylose content and surface area of the granules. The current evaluation suggests that the physiological occurrence of RS from maize starch might be predictable by reference to the in vitro RS value.

Seedling vigour in wheat - sources of variation for genetic and agronomic improvement

2002 ◽  
Vol 53 (1) ◽  
pp. 41 ◽  
Author(s):  
R. A. Richards ◽  
Z. Lukacs
Keyword(s):  
Linear Correlation ◽  
Slow Growth ◽  
Early Growth ◽  
Seedling Vigour ◽  
Breeding Programs ◽  
Significant Difference ◽  
Positive Linear Correlation ◽  
Sources Of Variation ◽  
And Performance ◽  
Seed Characteristics

The early growth of wheat is slow compared with that of barley and triticale. This is expected to limit the yield of wheat in environments where greater seedling vigour is advantageous. To overcome the slow growth of wheat, genetic sources of seedling vigour are required for use in breeding programs, and/or ways to increase seedling growth by manipulating seed characteristics. This study reports (i) new sources of and 3 heights at cutting (cutting was done when the grass reached 0.5, 1, and 1.5 m above the ground). The N fertiliser treatment did not yield any significant difference in DMD, ND, or IVDMD. Height at cutting had a significant (P < 0.05) effect on rumen DMD and ND and their degradability characteristics for all incubation times. There was a reduction in DMD and ND and their degradability characteristics as plant height increased at cutting. Similarly, as height at cutting increased there was a decline in IVDMD. There was a positive linear correlation between IVDMD and both DMD and ND at 48, 72, 96, and 120 h (r = 0.917, 0.923, 0.921, and 0.850 for DMD; r = 0.795, 0.814, 0.787, and 0.787 for ND). Hence, further study on intake and performance of animals is suggested to develop Napier-based diets for smallholders.

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