Selected Contribution: Role of spleen emptying in prolonging apneas in humans

2001 ◽  
Vol 90 (4) ◽  
pp. 1623-1629 ◽  
Author(s):  
Erika Schagatay ◽  
Johan P. A. Andersson ◽  
Magnus Hallén ◽  
Birger Pålsson
Keyword(s):  
Protein Concentration ◽  
Venous Blood ◽  
Hemoglobin Concentration ◽  
Diving Response ◽  
Short Term ◽  
Plasma Protein Concentration ◽  
Face Immersion ◽  
Short Term Adaptation ◽  
Hematological Changes

This study addressed the interaction between short-term adaptation to apneas with face immersion and erythrocyte release from the spleen. Twenty healthy volunteers, including ten splenectomized subjects, participated. After prone rest, they performed five maximal-duration apneas with face immersion in 10°C water, with 2-min intervals. Cardiorespiratory parameters and venous blood samples were collected. In subjects with spleens, hematocrit and hemoglobin concentration increased by 6.4% and 3.3%, respectively, over the serial apneas and returned to baseline 10 min after the series. A delay of the physiological breaking point of apnea, by 30.5% (17 s), was seen only in this group. These parameters did not change in the splenectomized group. Plasma protein concentration, preapneic alveolar Pco 2, inspired lung volume, and diving bradycardia remained unchanged throughout the series in both groups. Serial apneas thus triggered the hematological changes that have been previously observed after long apneic diving shifts; they were rapidly reversed and did not occur in splenectomized subjects. This suggests that splenic contraction occurs in humans as a part of the diving response and may prolong repeated apneas.

Effects of hypoproteinemia on blood volume and arterial pressure of volume-loaded dogs

1990 ◽  
Vol 259 (5) ◽  
pp. H1317-H1324
Author(s):  
R. D. Manning
Keyword(s):  
Body Weight ◽  
Arterial Pressure ◽  
Blood Volume ◽  
Plasma Protein ◽  
Protein Concentration ◽  
Control Period ◽  
Plasma Protein Concentration ◽  
Autologous Plasma ◽  
Protein Mass

Studies were performed in 14 conscious, anephric dogs to clarify the role of blood volume in the genesis of hypertension. The dogs were splenectomized and had plasma protein concentration (PPC) reduced to 2.7 g/dl by daily plasmapheresis for 9 days. This hypoproteinemia resulted in a 20% decrease in both blood volume and mean arterial pressure. On the 10th day the dogs were nephrectomized. On the 11th day after a 3-h control period with plasmapheresis, lactated Ringer equivalent to 10 or 20% of body weight was intravenously infused. By 25 h postinfusion blood volume had not increased, and the dogs were still hypotensive. At 25 h plasma protein mass was returned to normal by intravenous infusion of autologous plasma, the average blood volume of the three low PPC groups increased approximately 50%, and the arterial pressure increased greater than 60%. The decrease in PPC shifted the regression of blood volume on sodium space down the blood volume axis. In conclusion, the dependence of arterial pressure on blood volume was demonstrated by the decrease in both blood volume and arterial pressure after PPC reduction, the constancy of blood volume and pressure during Ringer infusion, and the increase in both volume and pressure after plasma infusion.

Effect of hemolysis on reflection coefficient determined by endogenous blood indicators

1987 ◽  
Vol 62 (6) ◽  
pp. 2252-2257 ◽  
Author(s):  
M. B. Maron ◽  
C. F. Pilati ◽  
K. C. Maender
Keyword(s):  
Reflection Coefficient ◽  
Plasma Protein ◽  
Protein Concentration ◽  
Venous Pressure ◽  
Hemoglobin Concentration ◽  
Plasma Protein Concentration ◽  
Fluid Filtration ◽  
Lung Lobe ◽  
Before And After ◽  
Osmotic Reflection Coefficient

The osmotic reflection coefficient (sigma) can be estimated from the increases in hematocrit and plasma protein concentration that result from fluid filtration occurring in an isolated perfused organ. We determined what effect perfusion pump-induced hemolysis has on the value of sigma determined by this technique in both the isolated canine left lower lung lobe (LLL) and forelimb by comparing estimates of sigma obtained before and after correction for hemolysis. Hemolysis was corrected by using the slopes of the relationships between hematocrit and plasma hemoglobin concentration and between the plasma protein and hemoglobin concentrations to correct hematocrit and protein concentration to a state of zero hemolysis. Uncorrected estimates of sigma in the LLL were 1.19 +/- 0.14 (SE) at a venous pressure (Pv) of 12 Torr (n = 7) and 0.90 +/- 0.02 at a Pv of 19 Torr (n = 6). Both sets of LLL's yielded sigma values of 0.77 +/- 0.03 after hemolysis correction. In the forelimb (n = 5), uncorrected and corrected estimates of sigma of 0.99 +/- 0.03 and 0.85 +/- 0.01, respectively, were obtained. The latter values were similar to sigma's (0.88 +/- 0.01) determined by lymph analysis in five additional forelimbs. We conclude that hemolysis results in overestimates of sigma. After hemolysis correction, this technique yields similar results to those obtained from lymph analysis for the forelimb and from published values for the LLL.

scholarly journals Genomics of long- and short- term adaptation in maize and teosinte

2018 ◽  
Author(s):  
Anne Lorant ◽  
Jeffrey Ross-Ibarra ◽  
Maud Tenaillon
Keyword(s):  
Natural Variation ◽  
Genetic Basis ◽  
Wild Relatives ◽  
Short Term ◽  
Short Term Adaptation ◽  
Maize Domestication ◽  
Cultivated Populations ◽  
Genetic Bases

Maize is an excellent model for the study of plant adaptation. Indeed, post domestication maize quickly adapted to a host of new environments across the globe. And work over the last decade has begun to highlight the role of the wild relatives of maize – the teosintes Zea mays ssp. parviglumis and ssp. mexicana – as excellent models for dissecting long-term local adaptation. Although human-driven selection associated with maize domestication has been extensively studied, the genetic bases of natural variation is still poorly understood. Here we review studies on the genetic basis of adaptation and plasticity in maize and its wild relatives. We highlight a range of different processes that contribute to adaptation and discuss evidence from natural, cultivated, and experimental populations. From an applied perspective, understanding the genetic bases of adaptation and the contribution of plasticity will provide us with new tools to both better understand and mitigate the effect of climate changes on natural and cultivated populations.

scholarly journals Genomics of long- and short- term adaptation in maize and teosinte

2018 ◽  
Author(s):  
Anne Lorant ◽  
Jeffrey Ross-Ibarra ◽  
Maud Tenaillon
Keyword(s):  
Natural Variation ◽  
Genetic Basis ◽  
Wild Relatives ◽  
Short Term ◽  
Short Term Adaptation ◽  
Maize Domestication ◽  
Cultivated Populations ◽  
Genetic Bases

Maize is an excellent model for the study of plant adaptation. Indeed, post domestication maize quickly adapted to a host of new environments across the globe. And work over the last decade has begun to highlight the role of the wild relatives of maize – the teosintes Zea mays ssp. parviglumis and ssp. mexicana – as excellent models for dissecting long-term local adaptation. Although human-driven selection associated with maize domestication has been extensively studied, the genetic bases of natural variation is still poorly understood. Here we review studies on the genetic basis of adaptation and plasticity in maize and its wild relatives. We highlight a range of different processes that contribute to adaptation and discuss evidence from natural, cultivated, and experimental populations. From an applied perspective, understanding the genetic bases of adaptation and the contribution of plasticity will provide us with new tools to both better understand and mitigate the effect of climate changes on natural and cultivated populations.

Short-Term Hematological Effects Upon Completion of a Four-Week Simulated Altitude Camp

2012 ◽  
Vol 7 (1) ◽  
pp. 79-83 ◽  
Author(s):  
Torben Pottgiesser ◽  
Laura A. Garvican ◽  
David T. Martin ◽  
Jesse M. Featonby ◽  
Christopher J. Gore ◽  
...  
Keyword(s):  
Sea Level ◽  
Venous Blood ◽  
Hemoglobin Concentration ◽  
Altitude Training ◽  
Simulated Altitude ◽  
Short Term ◽  
Hematological Effects ◽  
Hemoglobin Mass ◽  
Level Performance

Hemoglobin mass (tHb) is considered to be a main factor for sea-level performance after “live high–train low” (LHTL) altitude training, but little research has focused on the persistence of tHb following cessation of altitude exposure. The aim of the case study was to investigate short-term effects of various hematological measures including tHb upon completion of a simulated altitude camp. Five female cyclists spent 26 nights at simulated altitude (LHTL, 16.6 ± 0.4 h/d, 3000 m in an altitude house) where tHb was measured at baseline, at cessation of the camp, and 9 d thereafter. Venous blood measures (hemoglobin concentration, hematocrit, %reticulocytes, serum erythropoietin, ferritin, lactate dehydrogenase, and haptoglobin) were determined at baseline; on day 21 during LHTL; and at days 2, 5, and 9 after LHTL. Hemoglobin mass increased by 5.5% (90% confidence limits [CL] 2.5 to 8.5%, very likely) after the LHTL training camp. At day 9 after simulated LHTL, tHb decreased by 3.0% (90%CL −5.1 to −1.0%, likely). There was a substantial decrease in serum EPO (−34%, 90%CL −50 to −12%) at 2 d after return to sea level and a rise in ferritin (23%, 90%CL 3 to 46%) coupled with a decrease in %reticulocytes (−23%, 90%CL −34 to −9%) between day 5 and 9 after LHTL. Our findings show that following a hypoxic intervention with a beneficial tHb outcome, there may be a high probability of a rapid tHb decrease upon return to normoxic conditions. This highlights a rapid component in red-cell control and may have implications for the appropriate timing of altitude training in relation to competition.

scholarly journals Plasma Copper and Iron Levels and Plasma Paraphenylene Diamine Oxidase Activity (Plasma Copper Oxidase Activity) in Kwashiorkor

Blood ◽  
1959 ◽  
Vol 14 (8) ◽  
pp. 967-971 ◽  
Author(s):  
B. REIFF ◽  
H. SCHNIEDEN
Keyword(s):  
Oxidase Activity ◽  
Protein Concentration ◽  
Diamine Oxidase ◽  
Hemoglobin Concentration ◽  
Plasma Protein Concentration ◽  
Total Plasma Protein ◽  
Plasma Copper ◽  
Diamine Oxidase Activity ◽  
Copper Oxidase ◽  
Dietary Deficiency

Abstract 1. The plasma copper and iron levels, the hematocrit and hemoglobin concentration and the total plasma protein concentration were significantly lower in patients with kwashiorkor than in controls of the same age group. 2. There was a significant diminution in total circulating copper in the kwashiorkor patients. 3. Paraphenylene diamine oxidase activity was lower in the patients with kwashiorkor than in controls, indicating that there is a diminution in the level of the active group of ceruloplasmin which contains copper. 4. Whether the low plasma copper found is due to dietary deficiency, to malabsorption of copper, or whether it is secondary to inadequate protein intake is discussed.

Platelet-activating factor-induced microvascular dysfunction: role of adherent leukocytes

1990 ◽  
Vol 258 (1) ◽  
pp. G158-G163 ◽  
Author(s):  
P. Kubes ◽  
M. Suzuki ◽  
D. N. Granger
Keyword(s):  
Protein Concentration ◽  
Ischemia Reperfusion ◽  
Platelet Activating Factor ◽  
Microvascular Dysfunction ◽  
Fold Increase ◽  
Mucosal Injury ◽  
Plasma Protein Concentration ◽  
Intestinal Mucosal Injury ◽  
Adherent Leukocytes

Platelet-activating factor (PAF) has been implicated in the pathogenesis of intestinal mucosal injury associated with endotoxemia, inflammation, allergic reactions, and ischemia-reperfusion. Although it is generally held that PAF initiates mucosal injury by enhancing transcapillary fluid and protein exchange, the effects of PAF on the intestinal microvasculature have not been defined to date. In this study we examined the influence of local intrarterial infusions of PAF (4, 20, and 40 ng/min) on intestinal transcapillary, lymphatic, and transmucosal water and protein fluxes. All of these parameters were increased by each of the concentrations of PAF. PAF caused a large rise in venous hematocrit without a corresponding increase in venous plasma protein concentration and a 14- to 37-fold increase in vascular protein flux. Local intra-arterial infusion of PAF promoted leukocyte adherence to mesenteric venular endothelium, a process that is inhibited by the monoclonal antibody, MoAb IB4. PAF-induced increments in intestinal lymph flow, venous hematocrit, and vascular protein flux were greatly attenuated in animals treated with MoAb IB4. The results of this study indicate that PAF promotes the filtration of fluid and protein across intestinal capillaries. These microvascular effects of PAF are mediated, in part, by adherent leukocytes.

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