scholarly journals Lactic acid in mammalian cardiac muscle. —Part I. The stimulation maximum

1925 ◽  
Vol 99 (694) ◽  
pp. 8-20 ◽  
Keyword(s):  
Skeletal Muscle ◽  
Lactic Acid ◽  
Acid Content ◽  
Skeletal Muscles ◽  
Recovery Process ◽  
Muscular Contraction ◽  
Energy Output ◽  
Lactic Acid Content ◽  
Future Supply

The earlier work of Fletcher and Hopkins (1), and the more recent researches of A. V. Hill (2), Meyerhof (3) and their collaborators on the role of lactic acid in muscular contraction, have shown that oxygen is not required for the production of lactic acid, but only for its removal during the recovery process. This fact, coupled with the ability of a skeletal muscle to respond to stimulation until its lactic acid content is many times the resting value, enables the skeletal muscle to draw on its future supply of oxygen and to go into “oxygen debt.” The question naturally arises, are these facts also true of the heart muscle? Can the heart respond to stimulation when it has accumulated as large a concentration of lactic acid as is found in the skeletal muscle? In other words, How does the stimulation maximum of lactic acid of the heart compare with that of the skeletal muscle? A priori certain differences might be expected in view of the differences in the activity and nutrition of cardiac and skeletal muscles. In the first place the heart is not called upon to increase its energy output to anything like the extent of the skeletal muscle; nor does the heart have any long periods of comparative rest. It is always active and is contracting roughly one-third of the time. In addition the heart is provided with a very efficient circulation and has the first call on the oxygenated blood. For these reasons there seems to be no apparent need for the heart to have the ability of accumulating lactic acid to the same extent as the skeletal muscle; indeed, in view of the necessity for its constant activity, it would seem dangerous for it not to possess a mechanism by which the removal of lactic acid keeps pace with its production.

scholarly journals THE LACTIC ACID CONTENT OF MAMMALIAN BRAIN

1935 ◽  
Vol 110 (3) ◽  
pp. 637-642
Author(s):  
Bennett F. Avery ◽  
Stanley E. Kerr ◽  
Musa Ghantus
Keyword(s):  
Lactic Acid ◽  
Acid Content ◽  
Mammalian Brain ◽  
Lactic Acid Content

scholarly journals Effect of Lactic Acid Content into on during Miconazole Eye Drops to be Used for Infection Preventive

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Yoshimura K ◽  
Inoue Y ◽  
Koizumi A ◽  
Suzuki M ◽  
Itakura S ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Physical Properties ◽  
Acid Content ◽  
Eye Drops ◽  
Lactic Acid Content ◽  
The Stability

Purpose: The aims of this study were to prepare a 0.1% Miconazole (MCZ) eye-drop solution and to evaluate the stability and physical properties of the preparation.

scholarly journals Feed intake, rumenal pH and lactic acid in reindeer during transition to a complete ration added buffer and fat

Rangifer ◽  
1982 ◽  
Vol 2 (1) ◽  
pp. 31
Author(s):  
Ulla-Britt Bøe ◽  
Nicolai Gundersen ◽  
Harald Sletten ◽  
Endre Jacobsen
Keyword(s):  
Lactic Acid ◽  
General Condition ◽  
Feed Intake ◽  
Acid Content ◽  
Dramatic Decrease ◽  
Marine Oil ◽  
Rumen Ph ◽  
Lactic Acid Content

<p>Feed intake, general condition, rumenal pH and lactic acid content was followed during feeding of starved reindeer on a coventional diet (RF-71). The result was a dramatic decrease of rumen pH (pH=5.1 in experiment no. Ill) a few hours after feeding of the coventional diet, but this could be counteracted significantly by addition of buffer (pH=6.4 in experiment no. Ill) of hydrogenated marine oil (pH=6.1 in experiment no. Ill) to the ration. The highest content of the lactic acid in the rumen was 40 mM in animals fed RF-71, whereas addition of buffer or hydrogenated marine oil completely supressed accumulation of this acid.</p><p>Foropptak, pH og melkesyre i vomma hos rein under overgangsforing med kraftfor tilsatt buffer og fett.</p><p>Abstract in Norwegian&nbsp;/ Sammendrag: Forinntak, almentilstand, pH og melkesyreinnhold i vom ble registrert under foring av sultede rein med konvensjonelt kraftfor (reinfor 71 = RF-71). Det ble funnet et sterkt pH-fall i vomma (pH=5.1, fors&oslash;k III) f&aring; timer etter at dyrene startet &aring; spise RF-71. Denne effekten ble redusert ved tilsetting av buffer (pH=6.4, fors&oslash;k III) eller herdet marint fett (pH=6.1, fors&oslash;k III) til dietten. De dyr som ble foret med RF-71 hadde et melkesyreinnhold i vomma p&aring; opp til 40 mM. Tilsetting av buffer eller herdet marint fett til dietten forhindret akkumulering av melkesyre.</p><p>Poron rehunk&auml;ytt&ouml;, p&ouml;tsin pH ja maitohapposis&auml;lt&ouml; siirtym&auml;vaiheen ruokinnassa k&auml;ytett&auml;ess&auml; v&auml;kirehua, johon on lis&auml;tty puskuria ja rasvaa.</p><p>Abstract in Finnish / Yhteenveto: Rehunk&auml;ytto&auml;, yleistilaa, p&ouml;tsin pH:ta ja maitohapposis&auml;lt&ouml;&auml; tutkittiin ruokittaessa n&auml;lkiintyneit&auml; poroja tavanomaisella v&auml;kirehulla (poron 71 = RF-71). Joitakin tuntejaruokinnan aloittamisen j&auml;lkeen havaittiin voimakas p&ouml;tsin pH:n lasku (pH 5.1, koe III). T&auml;m&auml; vaikutus v&auml;heni kun poron nauttiman ravinnon joukkoon lis&auml;ttiin puskuria (pH 6.4, koe III) tai merikaloista valmistettua kovetettua rasvaa (pH 6.1, koe III). RF-71 rehua nauttineiden el&auml;inten p&ouml;tsin maitohapposis&auml;lt&ouml; oli 40 nM. Puskurin tai kovetetun merellisen el&auml;inper&auml;isen rasvan lis&auml;&auml;minen ravintoon ehk&auml;isi maitohapon kasaantumista.</p>

scholarly journals A Comprehensive Study of the Impacts of Oat β-Glucan and Bacterial Curdlan on the Activity of Commercial Starter Culture in Yogurt

Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5411
Author(s):  
Marek Aljewicz ◽  
Małgorzata Majcher ◽  
Beata Nalepa
Keyword(s):  
Lactic Acid ◽  
Acid Content ◽  
Starter Culture ◽  
Starter Cultures ◽  
Average Increase ◽  
Content Type ◽  
Lactic Acid Content ◽  
Production Increase ◽  
Addition Level ◽  
Comprehensive Study

This study provides important information about the impacts of various levels of oat (OBG) and bacterial (curdlan) β-glucan and fat contents in milk on survivability and metabolism of yogurt starter cultures. The results show that addition of β-glucans in the concentration higher than 0.25% reduced starter bacterial counts during storage and prolonged the milk acidification process. A significant increase in lactose consumption by starter cultures was noted in the yogurt samples with OBG addition up to 0.75%. The highest (by 567% on average) increase in lactic acid content was noted in the control yogurts. Whereas the lowest (by 351%) increase in lactic acid content was noted in yogurts with OBG. After 28-day storage, the acetic aldehyde content was significantly influenced by fat content, type and addition level of polysaccharide. A higher increase in acetoin content was noted in samples with 0.25% than in samples with 1% of polysaccharides. In turn, significantly lower increases in diacetyl and 2,3-pentanedione contents were observed in the yogurt samples with OBG than in these with curdlan, with diacetyl production increase along with the higher concentration of the polysaccharide. The addition of OBG and curdlan to milk contributed to differences in the starter culture metabolism, consequently, in the milk acidification dynamics.

scholarly journals Tenogenic Contribution to Skeletal Muscle Regeneration: The Secretome of Scleraxis Overexpressing Mesenchymal Stem Cells Enhances Myogenic Differentiation In Vitro

2020 ◽  
Vol 21 (6) ◽  
pp. 1965
Author(s):  
Maximilian Strenzke ◽  
Paolo Alberton ◽  
Attila Aszodi ◽  
Denitsa Docheva ◽  
Elisabeth Haas ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Regeneration ◽  
Skeletal Muscles ◽  
Myogenic Differentiation ◽  
Muscular Contraction ◽  
Myoblast Fusion ◽  
Skeletal Muscle Regeneration ◽  
Potential Candidate ◽  
Musculoskeletal Tissue

Integrity of the musculoskeletal system is essential for the transfer of muscular contraction force to the associated bones. Tendons and skeletal muscles intertwine, but on a cellular level, the myotendinous junctions (MTJs) display a sharp transition zone with a highly specific molecular adaption. The function of MTJs could go beyond a mere structural role and might include homeostasis of this musculoskeletal tissue compound, thus also being involved in skeletal muscle regeneration. Repair processes recapitulate several developmental mechanisms, and as myotendinous interaction does occur already during development, MTJs could likewise contribute to muscle regeneration. Recent studies identified tendon-related, scleraxis-expressing cells that reside in close proximity to the MTJs and the muscle belly. As the muscle-specific function of these scleraxis positive cells is unknown, we compared the influence of two immortalized mesenchymal stem cell (MSC) lines—differing only by the overexpression of scleraxis—on myoblasts morphology, metabolism, migration, fusion, and alignment. Our results revealed a significant increase in myoblast fusion and metabolic activity when exposed to the secretome derived from scleraxis-overexpressing MSCs. However, we found no significant changes in myoblast migration and myofiber alignment. Further analysis of differentially expressed genes between native MSCs and scleraxis-overexpressing MSCs by RNA sequencing unraveled potential candidate genes, i.e., extracellular matrix (ECM) proteins, transmembrane receptors, or proteases that might enhance myoblast fusion. Our results suggest that musculotendinous interaction is essential for the development and healing of skeletal muscles.

Effect of diltiazem on skeletal muscle 3-O-methylglucose transport in bacteremic rats

1989 ◽  
Vol 256 (3) ◽  
pp. R716-R721
Author(s):  
M. V. Westfall ◽  
M. M. Sayeed
Keyword(s):  
Escherichia Coli ◽  
Skeletal Muscle ◽  
Low Temperature ◽  
Skeletal Muscles ◽  
Cytochalasin B ◽  
Sugar Transport ◽  
Male Rats ◽  
Saline Control ◽  
Permeability Changes

This study examined whether alterations in cellular Ca2+ regulation contribute to previously observed changes in skeletal muscle sugar transport during bacteremia. Fasted male rats received saline (control) or bacteria (4 X 10(10) Escherichia coli/kg) intraperitoneally. Twelve hours later, basal and insulin-mediated 3-O-methylglucose (3MG) transport was measured in isolated soleus muscles. Measurements of 3MG transport in the presence of cytochalasin b or at a low temperature (0.5 degree C) indicated that altered sugar transport in bacteremic rat muscles was not due to nonspecific membrane permeability changes. To determine the role of Ca2+ in the pathogenesis of altered sugar transport during bacteremia, rats were treated with the Ca2+ antagonist diltiazem (DZ, 0.6-2.4 mg/kg) at various times (0, 0 + 7.5, 10 h) after saline or bacterial injection. In bacteremic rats given 2.4 mg/kg DZ at 10 h, basal and insulin-mediated transport were similar to control values. This dose of DZ had little effect on control muscles. The addition of 20 microM DZ to the incubation media did not affect basal or insulin-mediated 3MG transport in bacteremic rat muscles. Addition of the Ca2+ agonist BAY K 8644 to the incubation media had no effect on sugar transport in bacteremic rat muscles but caused alterations in control rat muscles that were comparable to those observed in bacteremia. These results suggest that alterations in Ca2+ regulation could contribute to the previously observed changes in sugar transport in skeletal muscles from bacteremic rats.

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