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Query: UMLS:C0085631 (agitation)
 12,064 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A close relationship exists between the decrease in concentration of 2,3-diphosphoglycerate (2,3-DPG) and a fall in the pH of stored blood. Buffering the stored red cells with bicarbonate is one solution to the problem of maintaining pH during storage. The effectiveness of this buffer depends upon loss from the stored blood of carbonic acid in the form of CO2. We describe a system in which the CO2 is trapped in a small internal package which contains calcium hydroxide, or calcium hydroxide embedded in Silastic. A medium containing bicarbonate, adenine, glucose, phosphate and mannitol (BAGPM) is added after initial packing of the erythrocytes. With this approach, it has been possible to maintain 2,3-DPG at 92 percent of original, and ATP was approximately 62 percent of initial levels at the end of 42 days of storage if an internal Silastic bag containing calcium was used in bags agitated once weekly. More frequent agitation (five times weekly) produced acceptable maintenance of both 2,3-DPG (78 percent of original) and ATP (44 percent of original) after 42 days of storage when a Silastic block impregnated with calcium hydroxide was utilized to absorb CO2.
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PMID:Prolonged maintenance of 2,3-DPG in liquid blood storage: use of an internal CO2 trap to stabilize pH. 1 18

Containers constructed of polyvinylchloride (PVC) are used for the storage of platelet concentrates (PC) for transfusion, At 22 degrees C, pH often falls to such low levels (pH is less that 6.0) that viability is lost. Far lesser degrees of pH fall are observed in bags constructed of polyethylene (PE). In this study, pH, PO2, PCO2, platelet count, lactate concentration, microscopic morphology, and viability after 51-chromium labeling were evaluated during storage at 22 degrees C under a variety of circumstances. The results indicate that (1) pH falls because of the generation of lactic acid by platelet glycolysis and, under some circumstances, the retention of CO2. (2) Rate of pH fall is, therefore, roughly proportional to the platelet count. (3) PE is more permeable to gases, thereby allowing CO2 escape from and easier O2 entry into the stored PC; the higher O2 tensions suppress glycolysis by the Pasteur effect. (4) Adequate agitation and container size are critical if the beneficial effect of PE is to be obtained. (5) In general, platelets stored in PE containers have excellent viability in vivo although CO2 escape can result in elevations in pH which are deleterious. (6) Storage in a 10% CO2 atmosphere prevents these deletrrious pH elevations without otherwise impairing platelet viability; (7) Results similar to those achieved with PE can be achieved with PVC if this material is made thinner to allow easier penetration of gases
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PMID:Platelet storage at 22 degrees C: role of gas transport across plastic containers in maintenance of viability. 23 90

The results of the experiments on determination of the effect of aeration and agitation conditions on biosynthesis of tetracycline in the apparatus of semi-production capacity are discussed. It was shown that the antibiotic production level was not connected with the rate of oxygen solution expressed in the sulphite numbers, i.e. this parameter cannot be used as a scaling-up criterion. Accumulation of the antibiotic in the fermentation broth depended on the volume of the air supplied for aeration. It was determined that the level of CO2 dissolved in the fermentation broth did not reach the values having an inhibitory effect on the biosynthetic process.
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PMID:[Effect of the aeration and agitation states on tetracycline biosynthesis in semiproduction-capacity apparatus]. 41 74

Agitated, nitrogen-limited cultures of Phlebia tremellosa caused substantial changes in the distribution of 14C-labelled synthetic lignin (dehydrogenative polymerizate [DHP]) between water-soluble, dioxane-soluble, alkali-soluble, and insoluble fractions before much lignin carbon was metabolized to CO2. First, the insoluble form increased at the expense of the dioxane-soluble form. Later, the amounts of alkali-soluble and water-soluble 14C increased, and release of 14CO2 began. The molecular weight distribution of the dioxane-soluble lignin remained constant during degradation, but that of the water-soluble fraction changed to higher molecular weights. Culture agitation accelerated the attachment of suspended DHP to the mycelia and stimulated production of water-soluble 14C and 14CO2. The nonionic detergent Tween 80 also hastened release of 14CO2 and increased the early conversion of dioxane-soluble DHP to the alkali-soluble and insoluble forms. Oxidative polymerization is suggested as the first step in degradation of DHP by P. tremellosa.
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PMID:Intermediates and products of synthetic lignin (dehydrogenative polymerizate) degradation by Phlebia tremellosa. 174 43

Thyrotropin-releasing hormone (TRH) stimulates pituitary thyrotropin synthesis and release and also regulates autonomic nervous system functions by acting as a neuromodulator and neurotransmitter. In experimental animals a stimulation of ventilation by thyrotropin-releasing hormone was shown when applied at central nervous system sites that affect respiratory motor output. It was the goal of our study to investigate the respiratory properties of thyrotropin-releasing hormone on basal and stimulated (i.e. CO2-rebreathing) conditions following systemic thyrotropin-releasing hormone application in healthy humans. Thyrotropin-releasing hormone (200 micrograms, 400 micrograms intravenous) initiated a rapid short lasting rise of minute volume, ventilatory air-flow and alveolar oxygen tension under steady state breathing (P less than 0.001). Breathing frequency was less affected, heart rate rose concomitantly (P less than 0.001). While breathing with increasing concentrations of carbon dioxide, minute volume was higher under thyrotropin-releasing hormone than under placebo alone. Further effects (e.g. nausea, dizziness, palpitations) mostly appeared later than respiratory changes and thus may not be responsible for their initiation. Our findings prove systemic thyrotropin-releasing hormone to be a strong respiratory stimulant in man. Response in respiratory output was also accompanied by central nervous system-effects (e.g. dizziness, restlessness, augmented vigilance). The mode of thyrotropin-releasing hormone effects on respiration after peripheral administration is still speculative. An augmented sympathetic output or a direct receptor mediated action at central nervous system sites may be responsible, while a peripheral effect cannot be excluded.
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PMID:Thyrotropin-releasing hormone has stimulatory effects on ventilation in humans. 190 74

Transport of 14C-labeled acetic, propionic (PA), butyric, valeric, heptanoic (HA), and octanoic (OA) acids across the Madin Darby canine kidney (MDCK) epithelial cell monolayer grown on a porous polycarbonate membrane was studied in Hanks' balanced salt solution (HBSS) at 37 degrees C in both apical-to-basolateral and basolateral-to-apical directions. At micromolar concentrations of solutes, metabolic decomposition was significant as evidenced by [14C]CO2 production during the OA transport. The apparent permeability (Pe) indicates that as lipophilicity increases, diffusion across the "unstirred" boundary layer becomes rate limiting. In support of this notion, transport of OA and HA was enhanced by agitation, showed an activation energy of 3.7 kcal/mol for OA, and resulted in identical Pe values for both transport directions. Analysis of Pe changes with varying alkyl chain length resulted in a delta G of -0.68 +/- 0.09 kcal/mol for -CH2-group transfer from an aqueous phase to the MDCK cells. When the intercellular tight junctions were opened by the divalent chelator EGTA in Ca2+/Mg2(+)-free HBSS, transport of the fluid-phase marker Lucifer yellow greatly increased because of paracellular leakage. PA transport also showed a significant increase, but OA transport was independent of EGTA. Although albumin also undergoes paracellular transport in the presence of EGTA and OA binds strongly to albumin, OA transport in EGTA solution was unchanged by albumin. These observations indicate that transmembrane transport is the major mechanism for lipophilic substances. The present study, together with earlier work on the transport of polar substances, shows that the MDCK cell monolayer is an excellent model of the transepithelial transport barrier.
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PMID:Transepithelial transport of aliphatic carboxylic acids studied in Madin Darby canine kidney (MDCK) cell monolayers. 211 19

Nalbuphine hydrochloride, an agonist-antagonist opioid, is reported to reverse the respiratory depression of moderate doses of fentanyl (20 micrograms.kg-1) and still provide good analgesia. We report four patients having abdominal aortic aneurysm repair in which we attempted to reverse the respiratory depression of large doses of fentanyl (50-75 micrograms.kg-1) with nalbuphine (0.3 mg.kg-1, 0.1 mg.kg-1 or 0.05 mg.kg-1). Nalbuphine reversed respiratory depression in all four patients and the respiratory rate increased from 10 to 23 breaths per minute, end-tidal CO2 decreased from 7.0 +/- 0.3 per cent to 5.6 +/- 0.7 per cent, and peak inspiratory pressure after 0.1 seconds increased from 4 +/- 1.4 to 13 +/- 2.6 mmHg. However, hypertension, increased heart rate, and significant increase in analogue pain scores accompanied reversal of respiratory depression. Agitation, nausea, vomiting, and cardiac dysrhythmias also were observed frequently. We do not recommend the use of nalbuphine to facilitate early extubation of the trachea after large doses of fentanyl for abdominal aortic surgery.
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PMID:Side effects of nalbuphine while reversing opioid-induced respiratory depression: report of four cases. 165

For investigations of CO2-stunning of feeder- and slaughter-pigs parameters of behaviour, blood-gas-analyses and electroencephalograms were chosen. The following results were obtained: 1. Blood-gas-analyses proved that the CO2-stunning does not produce unconsciousness due to a lack of oxygen. 2. The criterias of general anaesthesia: unconsciousness, muscle-relaxation and analgesia with total reversibility could be confirmed. 3. The violent convulsive symptoms were evaluated as reactions identical with the stage II of GUEDEL's scheme of anaesthesia. 4. Muscular agitation, which sometimes appeared a few seconds before the stage of excitation, was judged to belong either to the start of the excitation phase or to the end of Guedel's stage of analgesia, during which the sensitivity is decreased. Neither study of behavior nor objective measurements showed, during the first 10 to 20 seconds of exposure to the CO2, any sign of pain or suffering related to the Act for Prevention of Cruelty to Animals, and accordingly such suffering should not be ascribed to the CO2 stunning method.
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PMID:[CO2-stunning of swine for slaughter from the anesthesiological viewpoint]. 249 19

Citrated platelet-rich human plasma was subjected to one of three experimental treatments at 37 degrees C for 15 min: stirring, bubbling (with stirring), and gentle agitation achieved by a rocking motion. The last two were "equiconvective" as judged by equilibration rates with CO2 and O2 but presumably differed in the shear stress they imposed on the cells. Stirring platelets in normal air or 5% CO2-air caused no significant aggregation. Bubbling air through platelet-rich plasma increased its pH and marked aggregation occurred. Bubbling CO2-air caused the platelet-rich plasma pH to attain its physiological level of 7.4 with less aggregation. In both cases, subsequent ADP-induced aggregation was diminished. Rocking (without stirring) in the presence of CO2-air caused negligible aggregation in platelets and an enhanced response to ADP. Because of the marked difference between the two equiconvective treatments, bubbling and rocking, the main factor in activating the human platelets is suggested to be shear stress (potentiated by high pH), with perhaps a lesser contribution from the air-plasma interface.
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PMID:Effects of gas bubbling and other forms of convection on platelets in vitro. 279 18

The effect of various agitation conditions on growth of the cell population of Bacillus subtilis and production of riboxin was studied. The physiological state of the culture was estimated by the relations for the respiration coefficient CO2/O2, the yield of the constructive metabolism products (X + P) by oxygen Yx + p/O2, the ratio of consumed glucose to ammonium nitrogen S/NH4+, the coefficient of the cell biosynthetic activity Yp/x and the parameter of the energetic efficiency of the substrate usage (eta). It was shown that the maximum biosynthetic activity was mainly defined by the culture state in the trophophase. The growth of the cell population in this case should proceed under conditions of conjugated aerobic metabolism. It was found that directed biosynthesis of riboxin could be provided by changing the cultivation conditions and estimation of the culture physiological state by the parameters of the material and energy balance.
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PMID:[Assessment by the material and energy balance method of the directed biosynthesis of riboxin by altering the external culture conditions]. 310 37


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