Krebs buffer (10X, pH 7.2)

2007 ◽  
Vol 2007 (23) ◽  
pp. pdb.rec11255-pdb.rec11255
Keyword(s):  
Krebs Buffer

HCl-induced inflammatory mediators in cat esophageal mucosa and inflammatory mediators in esophageal circular muscle in an in vitro model of esophagitis

2006 ◽  
Vol 290 (6) ◽  
pp. G1307-G1317 ◽  
Author(s):  
Ling Cheng ◽  
Weibiao Cao ◽  
Claudio Fiocchi ◽  
Jose Behar ◽  
Piero Biancani ◽  
...  
Keyword(s):  
Inflammatory Mediators ◽  
Platelet Activating Factor ◽  
Circular Muscle ◽  
Muscle Layer ◽  
Normal Mucosa ◽  
Esophageal Mucosa ◽  
Mrna Levels ◽  
Physiol Gastrointest Liver ◽  
Krebs Buffer

Platelet-activating factor (PAF) and interleukin-6 (IL-6) are produced in the esophagus in response to HCl and affect ACh release, causing changes in esophageal motor function similar to esophagitis (Cheng L, Cao W, Fiocchi C, Behar J, Biancani P, and Harnett KM. Am J Physiol Gastrointest Liver Physiol 289: G418–G428, 2005). We therefore examined HCl-activated mechanisms for production of PAF and IL-6 in cat esophageal mucosa and circular muscle. A segment of normal mucosa was tied at both ends, forming a mucosal sac (Cheng L, Cao W, Fiocchi C, Behar J, Biancani P, and Harnett KM. Am J Physiol Gastrointest Liver Physiol 289: G860–G869, 2005) that was filled with acidic Krebs buffer (pH 5.8) or normal Krebs buffer (pH 7.0) as control and kept in oxygenated Krebs buffer for 3 h. The supernatant of the acidic sac (MS-HCl) abolished contraction of normal muscle strips in response to electric field stimulation. The inhibition was reversed by the PAF antagonist CV3988 and by IL-6 antibodies. PAF and IL-6 levels in MS-HCl and mucosa were significantly elevated over control. IL-6 levels in mucosa and supernatant were reduced by CV3988, suggesting that formation of IL-6 depends on PAF. PAF-receptor mRNA levels were not detected by RT-PCR in normal mucosa, but were significantly elevated after exposure to HCl, indicating that HCl causes production of PAF and expression of PAF receptors in esophageal mucosa and that PAF causes production of IL-6. PAF and IL-6, produced in the mucosa, are released to affect the circular muscle layer. In the circular muscle, PAF causes production of additional IL-6 that activates NADPH oxidase to induce production of H2O2. H2O2 causes formation of IL-1β that may induce production of PAF in the muscle, possibly closing a self-sustaining cycle of production of inflammatory mediators.

Use of Polyethyleneglycol for Porcine Islet Cryopreservation

1997 ◽  
Vol 6 (6) ◽  
pp. 613-621 ◽  
Author(s):  
Bénédicte Monroy ◽  
Jiri Honiger ◽  
Sylviane Darquy ◽  
Gérard Reach
Keyword(s):  
Insulin Secretion ◽  
Polyethylene Glycol ◽  
Liquid Nitrogen ◽  
Hollow Fiber ◽  
Experimental Diabetes ◽  
Standard Procedure ◽  
Protective Agent ◽  
Porcine Islet ◽  
Krebs Buffer

The aim of this work was to determine whether polyethylene glycol 20000 Da (PEG) could be used as protective agent in porcine islet cryopreservation. Cryopreservation was performed on 1-wk cultured pig islets and consisted in an overnight storage in liquid nitrogen. In a first set of experiments, we compared the in vitro function of PEG-cryopreserved islets to that of porcine islets cryopreserved under the standard procedure using dimethylsulfoxide (DMSO), by incubating the islets over 45 min in Krebs buffer containing either 2.8 or 10 mmol/L glucose. Insulin secretion of both types of islets reached a maximum at day 10 postthawing and had stimulation indices above 2 up to 3 wk after thawing. PEG-cryopreserved islets secreted more insulin than DMSO-treated islets and showed glucose-dependency insulin secretion in a 0-16.6 mmol/L glucose range. We also established that PEG-cryopreserved islets were as functional in vitro as nonfrozen tissue and that they could reverse experimental diabetes of the mouse for longer periods of time than noncryopreserved islets (p < 0.005 3 wk after transplantation) when implanted in the peritoneal cavity, being immunoprotected in a semipermeable hollow fiber. PEG can, therefore, be considered as a suitable cryoprotective compound for porcine islet storage.

scholarly journals Myogenic contractility is more dependent on myofilament calcium sensitization in term fetal than adult ovine cerebral arteries

2007 ◽  
Vol 293 (1) ◽  
pp. H548-H556 ◽  
Author(s):  
Renan J. Sandoval ◽  
Elisha R. Injeti ◽  
James M. Williams ◽  
William T. Georthoffer ◽  
William J. Pearce
Keyword(s):  
Calcium Influx ◽  
Cerebral Arteries ◽  
Calcium Sensitivity ◽  
Cytosolic Calcium ◽  
Stretch Ratio ◽  
Myogenic Tone ◽  
Postnatal Maturation ◽  
Calcium Sensitization ◽  
Myofilament Calcium Sensitivity ◽  
Krebs Buffer

Regulation of cytosolic calcium and myofilament calcium sensitivity varies considerably with postnatal age in cerebral arteries. Because these mechanisms also govern myogenic tone, the present study used graded stretch to examine the hypothesis that myogenic tone is less dependent on calcium influx and more dependent on myofilament calcium sensitization in term fetal compared with adult cerebral arteries. Term fetal and adult posterior communicating cerebral arteries exhibited similar myogenic responses, with peak tensions averaging 24 and 26% of maximum contractile force produced in any given tissue in response to an isotonic Krebs buffer containing 122 mM K+ (Kmax) at optimum stretch ratios (working diameter/unstressed diameter) of 2.19 and 2.23, respectively. Graded stretch increased cytosolic Ca2+ concentration at stretch ratios >2.0 in adult arteries, but increased Ca2+ concentration only at stretch ratios >2.3 in fetal arteries. In permeabilized arteries, myogenic tone peaked at a stretch ratio of 2.1 in both fetal and adult arteries. The fetal %Kmax values at peak myogenic tone were not significantly different at either pCa 7.0 (23%) or pCa 5.5 (25%) but were significantly less at pCa 8.0 (8.4 ± 2.3%). Conversely, adult %Kmax values at peak myogenic tone were significantly less at both pCa 8.0 (10.4 ± 1.8%) and pCa 7.0 (16%) than at pCa 5.5 (27%). The maximal extents of stretch-induced increases in myosin light chain phosphorylation in intact fetal (20%) and adult (17%) arteries were similar. The data demonstrate that the cerebrovascular myogenic response is highly conserved during postnatal maturation but is mediated differently in fetal and adult cerebral arteries.

A Plasma Factor Which Stimulates Prostacyclin Formation Is Increased In Diabetes

1981 ◽  
Author(s):  
M Johnson ◽  
A H Reece ◽  
H E Harrison
Keyword(s):  
Matched Control ◽  
Freezing And Thawing ◽  
Control Tissue ◽  
Plasma Factor ◽  
The Difference ◽  
Plasma Factors ◽  
And Control ◽  
Free Plasma ◽  
Krebs Buffer ◽  
Stimulation Of

Vascular prostacyclin (PGI2) generation is decreased in diabetes in experimental animals and in man. In this study, we have investigated the possibility that levels of a plasma factor (s) modifying PGI2 production are abnormal in diabetes. Aortic rings from diabetic or age-matched control rats were washed in Krebs buffer to reduce endogenous PGI2 formation. Addition of rat or human cell-free plasma stimulated PGI2 release by the “exhausted” vascular rings, and this activity was still present after freezing and thawing. The stimulation of PGI2 synthesis by control tissue was significantly greater (p<0.001) with plasma from diabetic animals (0.25±0.04ng/mg) than from controls (0.05±0.02ng/mg). Similarly, plasma from diabetic volunteers showed increased (p<0.05) PGI2-stimulatory activity. Diabetic tissue was less responsive than control tissue to stimulation by diabetic plasma, and the difference between diabetic and control plasmas was not apparent. This suggests that the abnormal vascular PGI2 synthesis in diabetes may be due to a defect in the vessel wall and not to lack of stimulatory plasma factors.

CO modulates pulmonary vascular response to acute hypoxia: relation to endothelin

2004 ◽  
Vol 286 (1) ◽  
pp. H137-H144 ◽  
Author(s):  
Fan Zhang ◽  
Jun Ichi Kaide ◽  
LiMing Yang ◽  
Houli Jiang ◽  
Shuo Quan ◽  
...  
Keyword(s):  
Pulmonary Arterial Pressure ◽  
Acute Hypoxia ◽  
Isometric Tension ◽  
Vascular Response ◽  
Tension Development ◽  
Pulmonary Vasoconstriction ◽  
Pulmonary Arterial ◽  
Hypoxic Gas Mixture ◽  
Concentration Response Curve ◽  
Krebs Buffer

Pulmonary intralobar arteries express heme oxygenase (HO)-1 and -2 and release carbon monoxide (CO) during incubation in Krebs buffer. Acute hypoxia elicits isometric tension development (0.77 ± 0.06 mN/mm) in pulmonary vascular rings treated with 15 μmol/l chromium mesoporphyrin (CrMP), an inhibitor of HO-dependent CO synthesis, but has no effect in untreated vessels. Acute hypoxia also induces contraction of pulmonary vessels taken from rats injected with HO-2 antisense oligodeoxynucleotides (ODN), which decrease pulmonary HO-2 vascular expression and CO release. Hypoxia-induced contraction of vessels treated with CrMP is attenuated ( P < 0.05) by endothelium removal, by CO (1–100 μmol/l) in the bathing buffer, and by endothelin-1 (ET-1) receptor blockade with L-754142 (10 μmol/l). CrMP increases ET-1 levels in pulmonary intralobar arteries, particularly during incubation in hypooxygenated media. CrMP also causes a leftward shift in the concentration-response curve to ET-1, which is offset by exogenous CO. In anesthetized rats, pretreatment with CrMP (40 μmol/kg iv) intensifies the elevation of pulmonary artery pressure elicited by breathing a hypoxic gas mixture. However, acute hypoxia does not elicit augmentation of pulmonary arterial pressure in rats pretreated concurrently with CrMP and the ET-1 receptor antagonist L-745142 (15 mg/kg iv). These data suggest that a product of HO activity, most likely CO, inhibits hypoxia-induced pulmonary vasoconstriction by reducing ET-1 vascular levels and sensitivity.

Thromboxane A2 mediates increased pulmonary microvascular permeability after intestinal reperfusion

1997 ◽  
Vol 82 (2) ◽  
pp. 592-598 ◽  
Author(s):  
Richard H. Turnage ◽  
John L. Lanoue ◽  
Kevin M. Kadesky ◽  
Yan Meng ◽  
Stuart I. Myers
Keyword(s):  
Intestinal Ischemia ◽  
Thromboxane A2 ◽  
Microvascular Permeability ◽  
Sprague Dawley ◽  
Pulmonary Vasoconstriction ◽  
Sprague Dawley Rats ◽  
Pulmonary Arterial ◽  
Synthase Inhibitor ◽  
Krebs Buffer

Turnage, Richard H., John L. LaNoue, Kevin M. Kadesky, Yan Meng, and Stuart I. Myers. Thromboxane A2 mediates increased pulmonary microvascular permeability after intestinal reperfusion. J. Appl. Physiol. 82(2): 592–598, 1997.—This study examines the hypothesis that intestinal reperfusion (IR)-induced pulmonary thromboxane A2(TxA2) release increases local microvascular permeability and induces pulmonary vasoconstriction. Sprague-Dawley rats underwent 120 min of intestinal ischemia and 60 min of IR. Sham-operated animals (Sham) served as controls. After IR or Sham, the pulmonary vessels were cannulated, and the lungs were perfused in vitro with Krebs buffer. Microvascular permeability was quantitated by determining the filtration coefficient ( K f), and pulmonary arterial (Ppa), venous (Ppv), and capillary (Ppc) pressures were measured to calculate vascular resistance (Rt). After baseline measurements, imidazole (TxA2 synthase inhibitor) or SQ-29,548 (TxA2-receptor antagonist) was added to the perfusate; then K f, Ppa, Ppv, and Ppc were again measured. The K fof lungs from IR animals was four times greater than that of Sham ( P = 0.001), and Rt was 63% greater in the injured group ( P = 0.01). Pc of IR lungs was twice that of controls (5.4 ± 1.0 vs. 2.83 ± 0.3 mmHg, IR vs. Sham, respectively; P < 0.05). Imidazole or SQ-29,548 returned K fto baseline measurements ( P < 0.05) and reduced Rt by 23 and 17%, respectively ( P < 0.05). IR-induced increases in Pc were only slightly reduced by 500 μg/ml imidazole (14%; P = 0.05) but unaffected by lower doses of imidazole (5 or 50 μg/ml) or SQ-29,548. These data suggest that IR-induced pulmonary edema is caused by both increased microvascular permeability and increased hydrostatic pressure and that these changes are due, at least in part, to the ongoing release of TxA2.

Silk suture used in standard organ bath studies contracts upon exposure to Krebs buffer

2002 ◽  
Vol 48 (3) ◽  
pp. 179-183 ◽  
Author(s):  
Tracy Tazzeo ◽  
Jianmin Zuo ◽  
Russ Ellis ◽  
Luke J. Janssen
Keyword(s):  
Silk Suture ◽  
Organ Bath ◽  
Krebs Buffer

scholarly journals Effects of Sevoflurane and Adenosine Receptor Antagonist on the Sugammadex-Induced Recovery from Rocuronium-Induced Neuromuscular Blockade: An Ex-vivo Study

2020 ◽  
Author(s):  
Yong Beom Kim ◽  
Jae-Moon Choi ◽  
Chungon Park ◽  
Hey-Ran Choi ◽  
Junyong In ◽  
...  
Keyword(s):  
Neuromuscular Blockade ◽  
Adenosine Receptor ◽  
Ex Vivo ◽  
Neuromuscular Blocking ◽  
Blocking Effect ◽  
Organ Bath ◽  
Sprague Dawley ◽  
Buffer Solution ◽  
Recovery Pattern ◽  
Krebs Buffer

Abstract Background: Sevoflurane affects on the A1 receptor in the central nervous system (CNS) and potentiates the action of neuromuscular blocking agents. In the present study, we investigated whether sevoflurane (SEVO) has the ability to potentiate the neuromuscular blocking effect of rocuronium and if the specific antagonist of adenosine receptor (SLV320) can reverse this effect. Methods: Phrenic nerve–hemidiaphragm tissue specimens were obtained from forty Sprague-Dawley (SD) rats. The specimens were immersed in an organ bath filled with Krebs buffer and stimulated by a train-of-four (TOF) pattern using indirect supramaximal stimulation at 20 s intervals. The specimens were randomly allocated to control, 2-chloroadenosine (CADO), SEVO, or SLV320+SEVO groups. In the CADO and SLV320+SEVO groups, CADO and SLV320 were added to the organ bath from the start to a concentration of 10 μM and 10 nM, respectively. We then proceeded with rocuronium-induced blockade of >95% depression of the first twitch tension of TOF (T1) and TOF ratio (TOFR). In the SEVO and SLV320+SEVO groups, SEVO was added to the Krebs buffer solution to concentration of 400 - 500 μM for 10 min. Sugammadex-induced T1 and TOFR recovery was monitored for 30 min until >95% of T1 and >0.9 of TOFR were confirmed, and the recovery pattern was compared by plotting these data. Results: There were no significant differences in the recovery pattern between the control and SEVO groups. However, there were significant differences between the SEVO and SLV320+SEVO groups. Conclusion: Sevoflurane potentiates of rocuronium-induced neuromuscular blocking effect and delays sugammadex-induced recovery from neuromuscular blockade.

Role of cyclooxygenase metabolites in mediating platelet-induced baroreceptor dysfunction

1995 ◽  
Vol 269 (2) ◽  
pp. H599-H608 ◽  
Author(s):  
Z. Li ◽  
X. Su ◽  
M. W. Chapleau
Keyword(s):  
Platelet Activation ◽  
Carotid Sinus ◽  
Maximum Activity ◽  
Receptor Blocker ◽  
Rabbit Platelet ◽  
Synthesis Inhibitor ◽  
Rabbit Platelets ◽  
Before And After ◽  
Krebs Buffer

The goal of the study was to determine the role of cyclooxygenase metabolites in mediating platelet-induced suppression of baroreceptor activity. Exposure of the isolated carotid sinus of rabbits to thrombin-activated rabbit platelets (3 x 10(8) cells/ml Krebs buffer) decreased baroreceptor activity (P < 0.05) without significantly altering the slope of the pressure-activity relation (gain). The platelet-induced suppression of activity was not blocked but instead was even more pronounced after inhibition of cyclooxygenase with indomethacin; both maximum baroreceptor activity and gain were decreased markedly. The exacerbation of platelet-induced baroreceptor dysfunction contrasted with equivalent carotid vasoconstrictor responses to platelets before and after indomethacin. Furthermore, the stable thromboxane (TxA2) mimetic U-46619 caused similar vasoconstriction as platelets but did not influence baroreceptor gain or maximum activity. In contrast to indomethacin, the selective TxA2 synthesis inhibitor and receptor blocker CGS-22652 failed to influence platelet-induced suppression of activity. In summary, 1) rabbit platelet aggregating in carotid sinus suppress baroreceptor activity, which cannot be explained by the vasoconstriction, and 2) the suppression of activity is not mediated by TxA2 from platelets and is opposed by prostacyclin (PGI2) or other prostanoids produced in carotid sinus. The combination of impaired formation of PGI2 and platelet activation in atherosclerotic and thrombotic states may lead to profound baroreceptor dysfunction.

Endotoxin pretreatment enhances portal venous contractile response to endothelin-1

1996 ◽  
Vol 270 (1) ◽  
pp. H7-H15 ◽  
Author(s):  
B. H. Pannen ◽  
M. Bauer ◽  
J. X. Zhang ◽  
J. L. Robotham ◽  
M. G. Clemens
Keyword(s):  
Contractile Response ◽  
Portal Pressure ◽  
Normal Liver ◽  
Portal Circulation ◽  
Cell Velocity ◽  
Before And After ◽  
Red Blood Cell Velocity ◽  
Regression Slopes ◽  
Escherichia Coli Lipopolysaccharide ◽  
Krebs Buffer

To test whether endotoxin pretreatment modulates the portal hemodynamic response to endothelin (ET)-1 and phenylephrine (PE), two potent vasoconstrictors in the portal circulation of the normal liver, rats received intraperitoneal injections of Escherichia coli lipopolysaccharide (LPS; 1 mg/kg body wt) or saline. Livers were isolated after 6 or 24 h and perfused with Krebs buffer containing 5% autologous erythrocytes. Analyses of portal pressure-flow (P-Q) relationships and epifluorescence video microscopy were performed before and after ET-1 (10(-9) M) or PE (10(-5) M) administration. LPS pretreatment increased total portal resistances (Rt), zero-flow pressures (PQ = 0), and linear regression slopes of P-Q relationships, and decreased the sinusoidal diameters (Ds) and sinusoidal volumetric flow (Qv). The response to ET-1 was enhanced 6 and 24 h after LPS administration, leading to greater increases in Rt, PQ = 0, and slope and more pronounced decreases in Dx, red blood cell velocity (VRBC), and Qv. In contrast, PE effects were similar (PQ = 0, slope, Ds) or even attenuated (Rt, VRBC, Qv) in livers from LPS-treated compared with control animals. Thus endotoxin pretreatment increased the portal contractile response to ET-1 but not to PE. This enhanced ET-1 response appeared to occur at sinusoidal and presinusoidal levels and may contribute to endotoxin-induced hepatic microcirculatory failure.

Sign in / Sign up

Export Citation Format

Share Document