Tonic regulation of vascular tone by nitric oxide and chloride ions in rat isolated small coronary arteries

2000 ◽  
Vol 279 (6) ◽  
pp. H2604-H2611 ◽  
Author(s):  
Jonathan E. Graves ◽  
Iain A. Greenwood ◽  
William A. Large
Keyword(s):  
Nitric Oxide ◽  
Coronary Arteries ◽  
Vascular Tone ◽  
Physiological Saline ◽  
Chloride Ions ◽  
Bathing Solution ◽  
Contractile Mechanism ◽  
Mechanical Removal ◽  
Voltage Dependent ◽  
Physiological Saline Solution

We have investigated the involvement of Cl− in regulating vascular tone in rat isolated coronary arteries mounted on a small vessel myograph. Mechanical removal of the endothelium or inhibition of nitric oxide (NO) synthase with N ω-nitro-l-arginine methyl ester (l-NAME, 10−4 M) led to contraction of rat coronary arteries, and these contractions were sensitive to nicardipine (10−6 M). This suggests that release of NO tonically inhibits a contractile mechanism that involves voltage-dependent Ca2+ channels. In arteries contracted withl-NAME, switching the bathing solution to physiological saline solution with a reduced Cl− concentration potentiated the contraction. DIDS (5 × 10−6–3 × 10−4 M) caused relaxation of l-NAME-induced tension (IC50 = 55 ± 10 μM), providing evidence for a role of Cl−. SITS (10−5–5 × 10−4 M) did not affectl-NAME-induced tension, suggesting that DIDS is not acting by inhibition of anion exchange. Mechanical removal of the endothelium led to contraction of arteries, which was sensitive to DIDS (IC50 = 50 ± 8 μM) and was not affected by SITS. This study suggests that, in rat coronary arteries, NO tonically suppresses a contractile mechanism that involves a Cl−conductance.

Inositol trisphosphate activates a voltage-dependent calcium influx in Xenopus oocytes

1987 ◽  
Vol 231 (1262) ◽  
pp. 27-36 ◽  
Keyword(s):  
Chloride Channels ◽  
Calcium Influx ◽  
Inositol Trisphosphate ◽  
Ringer Solution ◽  
Chloride Ions ◽  
Bathing Solution ◽  
Calcium Dependent ◽  
Large Numbers ◽  
Voltage Dependent ◽  
Oocyte Membrane

Injection of inositol trisphosphate (IP 3 ) into oocytes of Xenopus laevis induces the appearance of a transient inward ( T in ) current on hyper­polarization of the membrane. This current is carried largely by chloride ions, but is shown to depend on extracellular calcium, because it is abolished by removal of calcium in the bathing fluid or by addition of manganese. Recordings with aequorin as an intracellular calcium indi­cator show that a calcium influx is activated by hyperpolarization after intracellular injection of IP 3 as well as after activation of neurotrans­mitter receptors thought to mediate a rise in IP 3 . Furthermore, by substituting barium for calcium in the bathing solution, inward barium currents can be recorded during hyperpolarization. We conclude that intracellular IP 3 modulates the activity of a class of calcium channels, so as to allow an influx of calcium on hyperpolarization. In normal Ringer solution this then leads to the generation of a chloride current, because of the large numbers of calcium-dependent chloride channels in the oocyte membrane.

scholarly journals Evaluation of effectiveness of 10% polyvinylpyrrolidone-iodine solution against infections in wire and pin holes for Ilizarov external fixators

2005 ◽  
Vol 123 (2) ◽  
pp. 58-61 ◽  
Author(s):  
Adelina Morais Camilo ◽  
José Carlos Bongiovanni
Keyword(s):  
Saline Solution ◽  
Kirschner Wire ◽  
Physiological Saline ◽  
Signs And Symptoms ◽  
Ilizarov Method ◽  
External Fixators ◽  
Iodine Solution ◽  
Superficial Infection ◽  
Mechanical Removal ◽  
Physiological Saline Solution

CONTEXT AND OBJECTIVE: Superficial infection at wire and pin insertions in the skin is a frequent disorder among patients utilizing the Ilizarov method. The objective of this study was to evaluate the effectiveness of daily topical application of 10% polyvinylpyrrolidone-iodine solution against infections of the holes for Kirschner wires and Schanz pins among patients using Ilizarov external fixators, in comparison with cleaning these holes only with 0.9% sterile physiological saline solution. DESIGN AND SETTING: Controlled randomized clinical trial, in the Orthopedics and Traumatology Outpatient Clinic, Hospital São Paulo, and Orthopedics and Traumatology Center of Jundiaí. METHODS: 30 patients were treated using the Ilizarov technique: 15 were instructed to apply 0.9% physiological saline dressing on the wire and pin insertions and 15 to apply 0.9% physiological saline plus 10% polyvinylpyrrolidone-iodine. Patients were evaluated at outpatient return visits for identification of signs and symptoms of superficial infection at wire and pin insertion sites. Samples were collected from cases of purulent exudate secretion, for culturing and clinical tests. RESULTS: The chi-squared and Fischer exact tests were applied, but no statistically significant association between the intervention of topical polyvinylpyrrolidone-iodine solution and the prevention of infections at wire and pin insertions could be found. CONCLUSIONS: Topical 10% polyvinylpyrrolidone-iodine solution applied daily to Kirschner wire and Schanz pin insertions did not reduce the incidence of superficial infection at these holes, in comparison with mechanical removal of dirt using 0.9% physiological saline solution.

scholarly journals Adipocyte-derived factor reduces vasodilatory capability in ob−/ob− mice

2009 ◽  
Vol 297 (2) ◽  
pp. H689-H695 ◽  
Author(s):  
Lusha Xiang ◽  
Robert L. Hester
Keyword(s):  
Vascular Tone ◽  
Saline Solution ◽  
Subcutaneous Fat ◽  
Physiological Saline ◽  
Muscle Stimulation ◽  
Wild Type ◽  
Physiological Saline Solution ◽  
Arteriolar Tone ◽  
Arteriolar Diameter ◽  
Hyperemic Response

Obesity is associated with impaired functional hyperemic response. We have shown that ATP-sensitive potassium (KATP) channels are important in mediating functional vasodilation. Adipocyte-derived factors (ADFs) can alter vascular tone via opening KATP channels. We hypothesize that, in an animal model of obesity, ADFs will decrease basal arteriolar tone by opening KATP channels, resulting in an attenuated functional vasodilation. We used wild-type (WT) mice and ob−/ ob− mice ( ob) to test this hypothesis. The spinotrapezius muscle was prepared for the microcirculatory observation of arcade arterioles, and we measured the vasodilatory responses to muscle stimulation. The basal arteriolar diameter was larger in ob mice compared with WT mice. The KATP channel inhibitor glibenclamide (10 μM) decreased arteriolar diameter in ob mice with no effect in WT mice. The increase in arteriolar diameter induced by muscle stimulation was attenuated in ob mice compared with WT mice. To determine the mechanisms for the opening of KATP channels, fat was collected from the ob mice, subcutaneous fat from around the spinotrapezius muscle (OBSF) or visceral fat (OBVF) and was incubated in physiological saline solution (PSS). The vasodilatory responses to the fat-conditioned PSS were determined in WT mice. Treatment with OBSF- or OBVF -conditioned PSS increased the arteriolar diameters in WT mice, a dilation that was inhibited by glibenclamide. The absolute diameters induced by muscle stimulation were not altered by the fat-conditioned PSS. These results suggest that, in ob mice, local ADFs reduce the functional vasodilatory capability via opening KATP channels.

Vasomotor control in mice overexpressing human endothelial nitric oxide synthase

2007 ◽  
Vol 293 (2) ◽  
pp. H1144-H1153 ◽  
Author(s):  
Elza D. van Deel ◽  
Daphne Merkus ◽  
Rien van Haperen ◽  
Monique C. de Waard ◽  
Rini de Crom ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Guanylyl Cyclase ◽  
Vascular Tone ◽  
Ros Scavenging ◽  
Enos Uncoupling ◽  
Voltage Dependent ◽  
Tissue Homogenates ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Nitric oxide (NO) plays a key role in regulating vascular tone. Mice overexpressing endothelial NO synthase [eNOS-transgenic (Tg)] have a 20% lower systemic vascular resistance (SVR) than wild-type (WT) mice. However, because eNOS enzyme activity is 10 times higher in tissue homogenates from eNOS-Tg mice, this in vivo effect is relatively small. We hypothesized that the effect of eNOS overexpression is attenuated by alterations in NO signaling and/or altered contribution of other vasoregulatory pathways. In isoflurane-anesthetized open-chest mice, eNOS inhibition produced a significantly greater increase in SVR in eNOS-Tg mice compared with WT mice, consistent with increased NO synthesis. Vasodilation to sodium nitroprusside (SNP) was reduced, whereas the vasodilator responses to phosphodiesterase-5 blockade and 8-bromo-cGMP (8-Br-cGMP) were maintained in eNOS-Tg compared with WT mice, indicating blunted responsiveness of guanylyl cyclase to NO, which was supported by reduced guanylyl cyclase activity. There was no evidence of eNOS uncoupling, because scavenging of reactive oxygen species (ROS) produced even less vasodilation in eNOS-Tg mice, whereas after eNOS inhibition the vasodilator response to ROS scavenging was similar in WT and eNOS-Tg mice. Interestingly, inhibition of other modulators of vascular tone [including cyclooxygenase, cytochrome P-450 2C9, endothelin, adenosine, and Ca-activated K+ channels] did not significantly affect SVR in either eNOS-Tg or WT mice, whereas the marked vasoconstrictor responses to ATP-sensitive K+ and voltage-dependent K+ channel blockade were similar in WT and eNOS-Tg mice. In conclusion, the vasodilator effects of eNOS overexpression are attenuated by a blunted NO responsiveness, likely at the level of guanylyl cyclase, without evidence of eNOS uncoupling or adaptations in other vasoregulatory pathways.

Adenoviral Gene Transfer of Nitric Oxide Synthase Increases Cerebral Blood Flow in Rats

Neurosurgery ◽  
2000 ◽  
Vol 47 (5) ◽  
pp. 1206-1215 ◽  
Author(s):  
Jürgen C. Lüders ◽  
Conrad C. Weihl ◽  
George Lin ◽  
Ghanashayam Ghadge ◽  
Marcus Stoodley ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Saline Solution ◽  
Physiological Saline ◽  
Enos Gene ◽  
Messenger Ribonucleic Acid ◽  
Physiological Saline Solution ◽  
Oxide Synthase ◽  
Replication Defective Adenovirus

Abstract OBJECTIVE Depletion of nitric oxide may play a role in the development of vasospasm after aneurysmal subarachnoid hemorrhage. Replenishment of nitric oxide might be a useful treatment for vasospasm. Using rats, we performed intracisternal injections of replication-defective adenovirus containing the endothelial nitric oxide synthase (eNOS) gene and determined the localization of and effect on cerebral blood flow of transgene expression. METHODS Rats underwent baseline measurement of cortical cerebral blood flow using laser Doppler flowmetry. Replication-defective adenovirus containing the Escherichia coliLacZ gene (Ad327β-Gal, n = 2/time point) or the bovine eNOS gene (AdCD8-NOS, n = 4/time point) or physiological saline solution was injected into the cisterna magna. Cerebral blood flow was measured 1, 2, 4, 7, or 14 days later, and the animals were killed. Expression of β-galactosidase activity from the LacZ gene was examined by histochemical staining and that of eNOS was examined by polymerase chain reaction assays of messenger ribonucleic acid. Brains were histopathologically examined for inflammation. RESULTS β-Galactosidase activity was observed throughout the leptomeninges and in some cells in the adventitia of small subarachnoid blood vessels in the Ad327β-Gal-injected rats. Messenger ribonucleic acid for eNOS was detected in the leptomeninges and brainstem 1 and 2 days after injection of AdCD8-NOS. Rats injected with Ad327β-Gal or physiological saline solution exhibited decreased cerebral blood flow beginning 2 days after virus injection and lasting up to 14 days after injection. Rats injected with AdCD8-NOS developed significant transient increases in cerebral blood flow 2 days after virus injection, followed by slight decreases in blood flow. There was inflammation in the subarachnoid space of all animals; the inflammation was qualitatively worse in animals injected with Ad327β-Gal, compared with rats injected with AdCD8-NOS or saline solution. CONCLUSION Intracisternal injection of replication-defective adenovirus containing the eNOS gene can transiently increase cerebral blood flow.

Sem Studies of Co-Cr-Mo Surgical Implant Alloy Corrosion Behavior

1982 ◽  
Vol 40 ◽  
pp. 520-521
Author(s):  
Ann Chidester Van Orden ◽  
John L. Chidester ◽  
Anna C. Fraker ◽  
Pei Sung
Keyword(s):  
Electron Microscopy ◽  
Corrosion Behavior ◽  
Anodic Polarization ◽  
Saline Solution ◽  
Saturated Calomel Electrode ◽  
Physiological Saline ◽  
X Ray ◽  
Physiological Saline Solution ◽  
Scanning Electron

The influence of small variations in the composition on the corrosion behavior of Co-Cr-Mo alloys has been studied using scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), and electrochemical measurements. SEM and EDX data were correlated with data from in vitro corrosion measurements involving repassivation and also potentiostatic anodic polarization measurements. Specimens studied included the four alloys shown in Table 1. Corrosion tests were conducted in Hanks' physiological saline solution which has a pH of 7.4 and was held at a temperature of 37°C. Specimens were mechanically polished to a surface finish with 0.05 µm A1203, then exposed to the solution and anodically polarized at a rate of 0.006 v/min. All voltages were measured vs. the saturated calomel electrode (s.c.e.).. Specimens had breakdown potentials near 0.47V vs. s.c.e.

Erythrophagocytosis by Entamoeba histolytica.- Ultrastructural Study

1972 ◽  
Vol 30 ◽  
pp. 156-157 ◽  
Author(s):  
Norberto Treviño ◽  
Alfredo Feria-Velasco ◽  
I. Ruiz de Chávez
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Entamoeba Histolytica ◽  
Ultrastructural Study ◽  
Saline Solution ◽  
Physiological Saline ◽  
Ultrastructural Level ◽  
Hot Plate ◽  
Physiological Saline Solution ◽  
Axenic Conditions

Although erythrophagocytosis by various species of Entamoeba is a well known phenomenon this has not yet been studied in detail at the ultrastructural level. The present work deals with the description of the incorporation process of erythrocytes by trophozoites of E. histolytica. For this study, trophozoites of E. histolytica, HK-9:NIH strain cultured in axenic conditions and washed human erythrocytes were placed on a hot plate at 37°C in physiological saline solution. After 5 minutes, 2.5% glutarldehyde was added and the samples were processed according to conventional techniques for electron microscopy.Based upon light microscopy studies on living trophozoites in contact with erythrocytes, it seems that erythrophagocytosis only takes place in one pole of the parasite.

Resection of bone by sagittal saw: Investigation of effects of blade speed, feed rate, and irrigation on temperature rise

2021 ◽  
pp. 095441192199948
Author(s):  
Ehsan Shakouri ◽  
Pezhman Ghorbani ◽  
Pedram Pourheidari ◽  
Saeed Fotuhi
Keyword(s):  
Temperature Rise ◽  
Feed Rate ◽  
Saline Solution ◽  
Physiological Saline ◽  
The State ◽  
Physiological Saline Solution ◽  
Allowable Range ◽  
Dry Conditions ◽  
Saw Blade ◽  
Oscillation Rate

Heat generation during bone cutting by sagittal saw may lead to temperature rise and possible incidence of thermal necrosis. The aim of the present research is to examine the effect of saw blade oscillation rate, blade feed rate, and irrigation by physiological saline solution on the bone temperature rise during sawing in order to determine the desired conditions for reducing the extent of thermal damage. For this purpose, empirical tests of bovine femur cutting were performed in 15 states, including five levels for the blade oscillation rate (10,000–18,000 cpm with 2000 cpm intervals) and three levels for the feed rate (10–30 mm.min−1 with 10 mm.min−1 intervals) for dry conditions; and five states, including five levels for the blade oscillation rate (10,000–18,000 cpm with 2000 cpm intervals) and one level in feed rate of 20 mm.min−1 for the irrigation conditions. The results indicated that the bone temperature rise had a direct relationship with the blade oscillation rate and an inverse relationship with its feed rate. In the state of no cooling, the minimum temperature rise (Δ T = 65.45°C) occurred at the blade speed of 10,000 cpm and feed rate of 30 mm.min−1, while in the state of sawing with irrigation, the temperature rise almost did not exceed the allowable range (Δ T ≤ 10°C). The results suggested that to lower the possibility of incidence of osteonecrosis in the bone resection by sagittal saw, cooling with physiological saline solution or application of the minimum blade oscillation rate and maximum feed rate is recommended.

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