scholarly journals Resistive evolution of general plasma configurations

1985 ◽  
Vol 28 (5) ◽  
pp. 1354 ◽  
Author(s):  
Guthrie Miller
Keyword(s):  
1987 ◽  
Author(s):  
J Vallés ◽  
M M Santos ◽  
J Aznar

Age, sex and platelet hyperactivity are factors that condition the development of coronary heart disease (CHD). Platelet function is believed to be influenced by its FA pattern, which can be modulated by the FA composition of plasma lipid fractions. Therefore, it seemed of interest to evaluate the effect of age and sex on platelet FA and ascertain whether the plasma influence on platelet FA is modified by age and sex. The study has been performed in 98 subjects, 49 couples, men (M) and women (W), living together and with the same dietary habits. The subjects were divided into three age groups : G I:16-40, GII:40-60,and G III: 60. Plasma and platelet FA of phospholipids (PL), triglycerides, and free FA fractions were evaluated by gas-chromatography. The results showed scarce differences in platelet FA in relation to sex. With respect to age, the percentages of 18:2 and 20:5 in most platelet lipid fractions both in M and in W decrease with age. More interesting are the differences in correlation found between plasma and platelet FA, particularly in the PL fraction, with age and sex. In this respect an increase in the correlation coefficient was found for 16:0,18:0 and 20:4 and a decrease for 20:5 in middle aged men and postmenopausic women (Table). The similarity between these two groups of subjects may have a physiopathological meaning, if we take into account that both are more susceptible to CHD and that an increase in 16:0, 18:0 and 20:4 as well as a decrease in 20:5 may condition a platelet hyperfuntion, circumstance that may be more easily produced by plasma influence in those subjects.The results of the present study also confirm that that in general plasma greately influences the platelet content in 18:1, 18:2 and to a lower extent the saturated FA.


1976 ◽  
Vol 54 (24) ◽  
pp. 2918-2923 ◽  
Author(s):  
A. Vianello ◽  
F. Macrì ◽  
C. Passera

Corn roots exposed to the Curvularia lunata phytotoxin show a decreased ability to absorb and to retain rubidium, sulphate, and leucine compared with control roots. The phytotoxin also decreased the amount of the amino acid incorporation into protein, whereas respiration was only slightly affected. The effect on active transport was more pronounced and rapid than loss of ions and inhibition of protein synthesis. The data suggest that the phytotoxin causes a general plasma membrane derangement similar to that caused by other phytotoxins, which results in a depression of the active transport, reflected in an inhibition of precursors of proteins and in a loss of ions. The toxin is to be regarded as a specific membrane poison.


1976 ◽  
Vol 21 (3) ◽  
pp. 437-448
Author(s):  
A.S. Breathnach ◽  
M. Gross ◽  
B. Martin ◽  
C. Stolinski

Fixed (glutaraldehyde, 3%) and unfixed specimens of rat buccal epithelium, striated muscle, and liver, were cryoprotected with glycerol, freeze-fractured, and replicated without sublimation. A comparison of fracture faces of general plasma membranes, nuclear membranes, mitochondrial membranes, and membranes of rough endoplasmic reticulum revealed no significant differences as between fixed and unfixed material. Apart from some membranes of liver endoplasmic reticulum, there was no evidence of aggregation or redistribution of intramembranous particles in the unfixed material. The results demonstrate that chemical prefixation of tissues for freeze-fracture is not always necessary, or even desirable, and that glycerol may not be as deeply or directly implicated in particle aggregation as previously thought. Fixation with glutaraldehyde alters the cleaving behaviour of plasma membrane at desmosomes and tight junctions, but not at gap junctions.


1979 ◽  
Vol 50 (7) ◽  
pp. 4685-4691 ◽  
Author(s):  
Kurt F. Schoenberg ◽  
Wulf B. Kunkel

PEDIATRICS ◽  
1968 ◽  
Vol 42 (1) ◽  
pp. 93-105
Author(s):  
David Baum ◽  
David H. Dillard ◽  
Hitoshi Mohri ◽  
Edward W. Crawford

Aspects of carbohydrate and lipid metabolism were examined in 10 infants whose core temperatures were lowered by external cooling to 15 to 20°C during cardiovascular surgery. Modest hyperglycemia, found with ether anesthesia, persisted in three patients not given glucose, but it was markedly increased in others given glucose infusions. Despite continued glucose infusion, plasma glucose returned toward prehypothermic levels with rewarming, provided epinephrine was not administered. When epinephrine was given, the return was slowed. These observations suggest diminished glucose utilization during hypothermia and arouse speculation concerning a related insulin abnormality. In general, plasma lactate and glycerol levels increased during hypothermia, reaching a peak after circulatory arrest and with rewarming. Plasma free fatty acid concentrations changed little until rewarming when they usually became depressed. Death occurred in all five infants in whom plasma glycerol and lactate levels were rising at the procedure's end, while plasma glycerol and lactate concentrations were falling on completion of the operation in patients who did well. These findings and the known importance of the liver in lactate and glycerol metabolism suggest that the course of plasma lactate and glycerol levels may prove useful as a reflection of hepatic dysfunction in patients undergoing hypothermic surgery.


1998 ◽  
Vol 5 (1) ◽  
pp. 143-152
Author(s):  
U. Hohenester ◽  
P. Kocevar ◽  
N.E. Hecker ◽  
R. Rodrigues-Herzog

1993 ◽  
Vol 74 (6) ◽  
pp. 3006-3012 ◽  
Author(s):  
S. P. Bailey ◽  
J. M. Davis ◽  
E. N. Ahlborn

Pharmacological manipulation of brain serotonergic [5-hydroxytryptamine (5-HT)] activity affects run time to exhaustion in the rat. These effects may be mediated by neurochemical, hormonal, or substrate mechanisms. Groups of rats were decapitated during rest, after 1 h of treadmill running (20 m/min, 5% grade), and at exhaustion. Immediately before exercise rats were injected intraperitoneally with 1 mg/kg of quipazine dimaleate (QD; a 5-HT agonist), 1.5 mg/kg of LY 53857 (LY; a 5-HT antagonist), or the vehicle (V; 0.9% saline). LY increased and QD decreased time to exhaustion (approximately 28 and 32%, respectively; P < 0.05). At fatigue, QD animals had greater plasma glucose, liver glycogen, and muscle glycogen concentrations but lower plasma free fatty acid concentration than did V and LY animals (P < 0.05). In general, plasma corticosterone and catecholamine levels during exercise in QD and LY rats were similar to those in V rats. Brain 5-HT and 5-hydroxyindole-3-acetic acid concentrations were higher at 1 h of exercise than at rest (P < 0.05), and the latter increased even further at fatigue in the midbrain and striatum (P < 0.05). Brain dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) were higher at 1 h of exercise (P < 0.05) but were similar to resting levels at fatigue. QD appeared to block the increase in DA and DOPAC at 1 h of exercise, and LY prevented the decrease in DA and DOPAC at fatigue (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)


1971 ◽  
Vol 13 (4) ◽  
pp. 265-288 ◽  
Author(s):  
R J Hastie ◽  
J B Taylor

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