Effect of Age on Oxygen-Binding in Normal Human Subjects

1976 ◽  
Vol 51 (2) ◽  
pp. 185-188
Author(s):  
P. M. Tweeddale ◽  
R. J. E. Leggett ◽  
D. C. Flenley
Keyword(s):  
Oxygen Saturation ◽  
Oxygen Tension ◽  
Inorganic Phosphate ◽  
Human Subjects ◽  
Oxygen Binding ◽  
Corpuscular Haemoglobin ◽  
Positive Correlation ◽  
Normal Human ◽  
Mean Corpuscular Haemoglobin ◽  
Effect Of Age

1. Oxygen-binding, plasma and intra-erythrocytic pH, and haemoglobin, 2,3-diphosphoglycerate and inorganic phosphate concentrations were measured in sixty-two healthy non-smokers aged between 18 and 89 years. 2. P50 (oxygen tension at 50% oxygen saturation) expressed at plasma pH 7·40 and Pco2 5·33 kPa showed a positive correlation with age. 3. This correlation of P50 with age was closer when P50 was expressed at a constant intra-erythrocytic pH 7·20. On average P50 at intra-erythrocytic pH 7·20 increased from 3·59 kPa at 20 years to 3·96 kPa at 90 years of age. 4. 2,3-Diphosphoglycerate, inorganic phosphate, haemoglobin and mean corpuscular haemoglobin concentrations did not correlate with P50 or with age.

Observations on a Relationship between Steroid Metabolism and the Concentration of Plasma Fibrinogen

1963 ◽  
Vol 10 (02) ◽  
pp. 400-405 ◽  
Author(s):  
B. A Amundson ◽  
L. O Pilgeram
Keyword(s):  
Blood Coagulation ◽  
Methyl Ether ◽  
Broad Spectrum ◽  
Human Subjects ◽  
Plasma Fibrinogen ◽  
Steroid Metabolism ◽  
Specific Site ◽  
Chain Reaction ◽  
Normal Human ◽  
A Chain

SummaryEnovid (5 mg norethynodrel and 0.075 mg ethynylestradiol-3-methyl ether) therapy in young normal human subjects causes an increase in plasma fibrinogen of 32.4% (P >C 0.001). Consideration of this effect together with other effects of Enovid on the activity of specific blood coagulatory factors suggests that the steroids are exerting their effect at a specific site of the blood coagulation and/or fibrinolytic system. The broad spectrum of changes which are induced by the steroids may be attributed to a combination of a chain reaction and feed-back control.

Relationship Between Mepacrine-Labelled Dense Body Number, Platelet Capacity to Accumulate 14C-5-HT and Platelet Density in the Bernard-Soulier and Hermansky-Pudlak Syndromes

1979 ◽  
Vol 42 (02) ◽  
pp. 694-704 ◽  
Author(s):  
F Rendu ◽  
A T Nurden ◽  
M Lebret ◽  
J P Caen
Keyword(s):  
Dense Body ◽  
Human Subjects ◽  
Human Platelets ◽  
Dense Bodies ◽  
Storage Organelle ◽  
Hereditary Disorders ◽  
Labelling Procedure ◽  
Normal Human ◽  
Hermansky Pudlak Syndrome ◽  
Bernard Soulier Syndrome

SummaryWe have used the mepacrine-labelling procedure to measure the dense body (serotonin storage organelle) content of the platelets of 2 hereditary disorders where abnormalities in dense body number were suspected. The platelets were incubated with mepacrine and examined by fluorescence microscopy. A mean number of 5.4 ± 0.8 (SD) dense bodies per platelet was calculated from the data obtained using platelets isolated from 40 normal human subjects. In contrast the platelets of 2 patients with the Bernard-Soulier syndrome contained an average of 14 and 17 labelled granules. This increase was associated with a much greater capacity of the platelets to accumulate 14C-5-HT. The opposite result was obtained using the platelets from 2 patients with the Hermansky-Pudlak syndrome which contained few granules labelled by mepacrine and took up less 14C-5-HT than normal human platelets. Centrifugation of the patients’ platelets on discontinuous sucrose gradients showed that the platelets of the 2 Bemard-Soulier patients were much denser than normal whereas a high proportion of low density platelets was observed in the Hermansky-Pudlak syndrome. These results further define the platelet abnormalities in the two syndromes and suggest that dense body number may be one of the factors governing platelet density.

ADRENERGIC CONTROL MECHANISM FOR ACTH SECRETION IN MAN

1973 ◽  
Vol 74 (2) ◽  
pp. 263-270 ◽  
Author(s):  
Yoshikatsu Nakai ◽  
Hiroo Imura ◽  
Teruya Yoshimi ◽  
Shigeru Matsukura
Keyword(s):  
Intravenous Infusion ◽  
Human Subjects ◽  
Blocking Agent ◽  
Inhibitory Effect ◽  
Plasma Acth ◽  
Acth Secretion ◽  
Glucose Levels ◽  
Alpha Receptors ◽  
Normal Human ◽  
Adrenergic Blocking

ABSTRACT In order to determine if an adrenergic mechanism is involved in the secretion of corticotrophin (ACTH), the effect of adrenergic-blocking or -stimulating agent on plasma ACTH, cortisol and glucose levels was studied in normal human subjects. The intravenous infusion of methoxamine, an alpha adrenergic-stimulating agent, caused a rise in plasma ACTH and cortisol. This increase in plasma ACTH and cortisol was significantly inhibited by the simultaneous administration of phentolamine, an alpha adrenergic-blocking agent, in combination with methoxamine. The intravenous infusion of propranolol, a beta adrenergic-blocking agent, caused no significant change in plasma ACTH and cortisol, although it enhanced the plasma ACTH response to insulin-induced hypoglycaemia. On the other hand, alpha adrenergicblockade by intravenous infusion of phentolamine significantly suppressed the plasma ACTH response to insulin-induced hypoglycaemia. These studies suggest a stimulatory effect of alpha receptors and a possible inhibitory effect of beta receptors on ACTH secretion in man.

Specialized systems for the processing of mnemonic information within the primate frontal cortex

1996 ◽  
Vol 351 (1346) ◽  
pp. 1455-1462 ◽  
Keyword(s):  
Frontal Cortex ◽  
Specific Activity ◽  
Human Subjects ◽  
Long Term Memory ◽  
Executive Processing ◽  
Severe Impairment ◽  
Normal Human ◽  
Short And Long Term ◽  
Cortical Association Areas

The lateral frontal cortex is involved in various aspects of executive processing within short- and long-term memory. It is argued that the different parts of the lateral frontal cortex make distinct contributions to memory that differ in terms of the level of executive processing that is carried out in interaction with posterior cortical systems. According to this hypothesis, the mid-dorsolateral frontal cortex (areas 46 and 9) is a specialized system for the monitoring and manipulation of information within working memory, whereas the mid-ventrolateral frontal cortex (areas 47/12 and 45) is involved in the active retrieval of information from the posterior cortical association areas. Data are presented which support this two-level hypothesis that posits two distinct levels of interaction of the lateral frontal cortex with posterior cortical association areas. Functional activation studies with normal human subjects have demonstrated specific activity within the mid-dorsolateral region of the frontal cortex during the performance of tasks requiring monitoring of self-generated and externally generated sequences of responses. In the monkey, lesions restricted to this region of the frontal cortex yield a severe impairment in performance of the above tasks, this impairment appearing against a background of normal performance on several basic mnemonic tasks. By contrast, a more severe impairment follows damage to the mid-ventrolateral frontal region and functional activation studies have demonstrated specific changes in activity in this region in relation to the active retrieval of information from memory.

scholarly journals Vitamin D and Blood Parameters

Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1017
Author(s):  
Thomas Müller ◽  
Lutz Lohse ◽  
Andreas Blodau ◽  
Katja Frommholz
Keyword(s):  
Vitamin D ◽  
Mean Corpuscular Volume ◽  
Plasma Concentrations ◽  
Blood Parameters ◽  
Vitamin D Supplementation ◽  
Mean Corpuscular Hemoglobin ◽  
Corpuscular Volume ◽  
Corpuscular Haemoglobin ◽  
Mean Corpuscular Haemoglobin ◽  
The Impact

Background: Vitamin D has a steroid- and an anabolic-resembling chemical structure. Vitamin D is essential for many processes in the human body after hydroxylation. Aims of the Study: To investigate the impact of 25-hydroxy-vitamin D plasma concentrations on the blood parameters number of erythrocytes, hematocrit, mean corpuscular hemoglobin and mean corpuscular volume. Methods: Serial assessments were done in 290 patients with multiple sclerosis and repeated after a mean interval of 245 days. A recommendation for vitamin D supplementation was given in case of a concentration lower than 20 ng/mL combined with a prescription of a formulation containing vitamin D but not vitamin K. Results: There was a fall of vitamin D in 119 subjects and a rise in 164, while no change appeared in 7 participants. When vitamin D values went down between both assessments moments, the computed increase of mean corpuscular haemoglobin was significantly lower compared with the rise of mean corpuscular haemoglobin associated with a vitamin D elevation. When vitamin D declined, the computed fall of mean corpuscular volume fall was significantly lower compared with the decrease of mean corpuscular volume, when vitamin D rose. Positive correlations were found between differences of vitamin D and mean corpuscular haemoglobin, respectively mean corpuscular volume. Inverse relations appeared between disparities of vitamin D and erythrocytes, respectively haematocrit. Conclusions: The elevation of vitamin D plasma levels provides enhanced preconditions for a better tissue oxygenation on a cellular level.

Asymmetric Distribution of Cooperativity in the Binding Cascade of Normal Human Hemoglobin. 1. Cooperative and Noncooperative Oxygen Binding in Zn-Substituted Hemoglobin†

Biochemistry ◽  
2005 ◽  
Vol 44 (36) ◽  
pp. 11925-11938 ◽  
Author(s):  
Jo M. Holt ◽  
Alexandra L. Klinger ◽  
Connie S. Yarian ◽  
Varsha Keelara ◽  
Gary K. Ackers
Keyword(s):  
Asymmetric Distribution ◽  
Oxygen Binding ◽  
Human Hemoglobin ◽  
Normal Human
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