bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Inhibitory Effects of Isoflurane on Protein Tyrosine Phosphorylation–modulated Contraction of Rat Aortic Smooth Muscle
Authors: Yu Jingui , Ogawa Koji , Tokinaga Yasuyuki , Mizumoto Kazuhiro , Kakutani Tetsuya , Hatano Yoshio 
Published: November 2004

Background
Tyrosine kinase-catalyzed protein tyrosine phosphorylation plays an important role in initiating and modulating vascular smooth muscle contraction. The aim of the current study was to examine the effects of isoflurane on sodium orthovanadate (Na3VO4), a potent protein tyrosine phosphatase inhibitor-induced, tyrosine phosphorylation-mediated contraction of rat aortic smooth muscle.

Methods
The Na3VO4-induced contraction of rat aortic smooth muscle and tyrosine phosphorylation of proteins including phospholipase Cgamma-1 (PLCgamma-1) and p44/p42 mitogen-activated protein kinase (MAPK) were assessed in the presence of different concentrations of isoflurane, using isometric force measurement and Western blotting methods, respectively.

Results
Na3VO4 (10(-4) m) induced a gradually sustained contraction and significant increase in protein tyrosine phosphorylation of a set of substrates including PLCgamma-1 and p42MAPK, all of which were markedly inhibited by genistein (5 x 10(-5) m), a tyrosine kinase inhibitor. Isoflurane (1.2-3.5%) dose-dependently depressed the Na3VO4-induced contraction (P < 0.05-0.005; n = 8). Isoflurane also attenuated the total density of the Na3VO4-induced, tyrosine-phosphorylated substrate bands and the density of tyrosine-phosphorylated PLCgamma-1 band and p42MAPK band (P < 0.05-0.005; n = 4) in a concentration-dependent manner.

Conclusion
The findings of the current study, that isoflurane dose-dependently inhibits both the Na3VO4-stimulated contraction and tyrosine phosphorylation of a set of proteins including PLCgamma-1 and p42MAPK in rat aortic smooth muscle, suggest that isoflurane depresses protein tyrosine phosphorylation-modulated contraction of vascular smooth muscle, especially that mediated by the tyrosine-phosphorylated PLCgamma-1 and MAPK signaling pathways.
Maternal Insufflation during the Second Trimester Equivalent Produces Hypercapnia, Acidosis, and Prolonged Hypoxia in Fetal Sheep
Authors: Uemura Kenichiro , McClaine Rebecca J. , de la Fuente Sebastian G. , Manson Roberto J. , Campbell Kurt A. , McClaine Deborah J. , White William D. , Stamler Jonathan S. , Eubanks W Steve , Reynolds James D. 
Published: November 2004

Background
Anecdotal reports suggest that the second trimester is the safest time to conduct a laparoscopic procedure on a pregnant patient, but this supposition has not been tested empirically.

Methods
Previously instrumented preterm sheep (total n = 8) at gestational day 90 (term, 145 days) were anesthetized and then insufflated with carbon dioxide for 60 min at a pressure of 15 mmHg. Cardiovascular parameters were continuously recorded while blood gas status was determined before and at 15-min intervals during and up to 2 h after insufflation.

Results
Insufflation produced minimal maternal blood gas or cardiovascular changes except for a significant reduction in uterine blood flow. The decrease in perfusion increased fetal arterial blood partial pressure of carbon dioxide and decreased fetal pH, oxygen saturation, and oxygen content; there was also progressive fetal hypotension and bradycardia. After manually deflating the ewe, uterine blood flow returned to normal, and the fetal partial pressure of carbon dioxide and pH changes resolved within 1 h. However, fetal oxygen saturation and content remained depressed, and fetal cardiovascular status continued to decline during the 2-h postinsufflation monitoring period.

Conclusion
Previous studies with near-term sheep determined that carbon dioxide pneumoperitoneum produces respiratory acidosis but does not decrease fetal oxygenation. In contrast, the current findings indicate that in the preterm fetus, insufflation-induced hypercapnia and acidosis are accompanied by prolonged fetal hypoxia and cardiovascular depression. This result suggests that additional work should be conducted to confirm the presumed safety of conducting minimally invasive procedures during the second trimester.
Mg2+Dependence of Halothane-induced Ca2+Release from the Sarcoplasmic Reticulum in Skeletal Muscle from Humans Susceptible to Malignant Hyperthermia
Authors: Duke Adrian M. , Hopkins Philip M. , Halsal Jane P. , Steele Derek S. 
Published: November 2004

Background
Recent work suggests that impaired Mg(2+) regulation of the ryanodine receptor is a common feature of both pig and human malignant hyperthermia. Therefore, the influence of [Mg(2+)] on halothane-induced Ca(2+) release from the sarcoplasmic reticulum was studied in malignant hyperthermia-susceptible (MHS) or -nonsusceptible (MHN) muscle.

Methods
Vastus medialis fibers were mechanically skinned and perfused with solutions containing physiologic (1 mm) or reduced concentrations of free [Mg(2+)]. Sarcoplasmic reticulum Ca(2+) release was detected using fura-2 or fluo-3.

Results
In MHN fibers, 1 mm halothane consistently did not induce sarcoplasmic reticulum Ca(2+) release in the presence of 1 mm Mg(2+). It was necessary to increase the halothane concentration to 20 mm or greater before Ca release occurred. However, when [Mg(2+)] was reduced below 1 mm, halothane became an increasingly effective stimulus for Ca(2+) release; e.g., at 0.4 mm Mg(2+), 58% of MHN fibers responded to halothane. In MHS fibers, 1 mm halothane induced Ca(2+) release in 57% of MHS fibers at 1 mm Mg(2+). Reducing [Mg(2+)] increased the proportion of MHS fibers that responded to 1 mm halothane. Further experiments revealed differences in the characteristics of halothane-induced Ca(2+) release in MHS and MHN fibers: In MHN fibers, at 1 mm Mg(2+), halothane induced a diffuse increase in [Ca(2+)], which began at the periphery of the fiber and spread slowly inward. In MHS fibers, halothane induced a localized C(2+)a release, which then propagated along the fiber. However, propagated Ca(2+) release was observed in MHN fibers when halothane was applied at an Mg(2+) concentration of 0.4 mm or less.

Conclusions
When Mg(2+) inhibition of the ryanodine receptor is reduced, the halothane sensitivity of MHN fibers and the characteristics of the Ca release process approach that of the MHS phenotype. In MHS fibers, reduced Mg(2+) inhibition of the ryanodine receptor would be expected to have a major influence on halothane sensitivity. The Mg dependence of the halothane response in MHN and MHS may have important clinical implications in circumstances where intracellular [Mg(2+)] deviates from normal physiologic concentrations.
Interaction of Ropivacaine with Cloned Cardiac Kv4.3/KChIP2.2 Complexes
Authors: Friederich Patrick , Solth Anna 
Published: November 2004

Background
Inhibition of cardiac K channels by local anesthetic may contribute to QTc interval prolongation of the electrocardiogram and induction of ventricular arrhythmia. The transient outward current Ito has been identified as a toxicologically relevant target of bupivacaine. S(-)-ropivacaine has been developed as a safer alternative to bupivacaine. The effects of S(-)-ropivacaine on Ito have not been investigated. In human ventricular myocardium, Ito is formed by Kv4.3 and KChIP2.2 subunits. Therefore, the aim of this study was to establish the effects of S(-)-ropivacaine on human Kv4.3/KChIP2.2 channels.

Methods
Kv4.3/KChIP2.2 complementary DNA cloned from human heart was transiently transfected in Chinese hamster ovary cells. The pharmacologic effects of S(-)-ropivacaine were investigated with the patch clamp method.

Results
Ropivacaine inhibited Kv4.3/KChIP2.2 channels in a concentration-dependent, stereospecific, and reversible manner. The IC50 value of S(-)-ropivacaine for inhibition of the charge conducted by Kv4.3/KChIP2.2 channel was 117 +/- 21 microm (n = 30). The local anesthetic accelerated macroscopic current decline with an IC50 value of 77 +/- 11 microm (n = 30). It shifted the midpoint of channel activation into the depolarizing direction, and it slowed recovery from inactivation without altering steady state inactivation. Kv4.3 channels are more sensitive to the inhibitory effect than Kv4.3/KChIP2.2 channels.

Conclusions
: The results are consistent with the idea that ropivacaine, by blocking Kv4.3/KChIP2.2 from the open state, interferes with the gating modifying effects of KChIP2.2 on Kv4.3 channels. Inhibition of Kv4.3/KChIP2.2 channels by the local anesthetic may contribute to the deterioration of cardiac function during events of intoxication.
Isoflurane and Desflurane Impair Right Ventricular–Pulmonary Arterial Coupling in Dogs
Authors: Kerbaul François , Rondelet Benoît , Motte Sophie , Fesler Pierre , Hubloue Ives , Ewalenko Patricia , Naeije Robert , Brimioulle Serge 
Published: November 2004

Background
Halogenated anesthetics depress left ventricular function, but their effects on the right ventricle have been less well studied. Therefore, the authors studied the effects of isoflurane and desflurane on pulmonary arterial (PA) and right ventricular (RV) properties at baseline and in hypoxia.

Methods
Right ventricular and PA pressures were measured by micromanometer catheters, and PA flow was measured by an ultrasonic flow probe. PA mechanics were assessed by flow-pressure relations and by impedance spectra derived from flow and pressure waves. RV contractility was assessed by end-systolic elastance (Ees), RV afterload was assessed by effective PA elastance (Ea), and RV-PA coupling efficiency was assessed by the Ees:Ea ratio. Anesthetized dogs were randomly assigned to increasing concentrations (0.5, 1, and 1.5 times the minimum alveolar concentration) of isoflurane (n = 7) or desflurane (n = 7) in hyperoxia (fraction of inspired oxygen, 0.4) and hypoxia (fraction of inspired oxygen, 0.1).

Results
Isoflurane and desflurane had similar effects. During hyperoxia, both anesthetics increased PA resistance and characteristic impedance, increased Ea (isoflurane, from 0.82 to 1.44 mmHg/ml; desflurane, from 0.86 to 1.47 mmHg/ml), decreased Ees (isoflurane, from 1.09 to 0.66 mmHg/ml; desflurane, from 1.10 to 0.72 mmHg/ml), and decreased Ees:Ea (isoflurane, from 1.48 to 0.52; desflurane, from 1.52 to 0.54) in a dose-dependent manner (all P < 0.05). Hypoxia increased PA resistance, did not affect characteristic impedance, increased afterload, and increased contractility. During hypoxia, isoflurane and desflurane had similar ventricular effects as during hyperoxia.

Conclusions
Isoflurane and desflurane markedly impair RV-PA coupling efficiency in dogs, during hyperoxia and hypoxia, both by increasing RV afterload and by decreasing RV contractility.
Intranasal Nicotine for Postoperative Pain Treatment
Authors: Flood Pamela , Daniel Danette 
Published: November 2004

Background
Despite pharmacological treatment, 70-80% of patients report moderate to severe pain after surgery. Because nicotine has been reported to have analgesic properties in animal and human volunteer studies, the authors assessed the analgesic efficacy of a single 3 mg dose of nicotine nasal spray administered before emergence from general anesthesia.

Methods
The authors conducted a randomized, double blind, placebo controlled trial of 20 healthy women (mean age 45 (SD 8) yr) who were to undergo uterine surgery through a low transverse incision. After the conclusion of surgery but before emergence from general anesthesia, the anesthesiologist administered either nicotine nasal spray or a placebo. Numerical analog pain score and morphine utilization and hemodynamic values were measured for 24 h.

Results
The patients treated with nicotine reported lower pain scores during the first hour after surgery (peak numerical analog score, 7.6 (SD 1.4) versus 5.3 (SD 1.6); P < 0.001) and used half the amount of morphine as the control group (12 (SD 6) versus 6 (SD 5) mg; P < 0.05). Patients who received nicotine still reported less pain than those in the control group 24 h after surgery (1.5 (SD 0.5) versus 4.9 (SD 1.4); P < 0.01). Systolic blood pressure was lower in the group that received nicotine (105 (SD 3) versus 122 (SD 3); P < 0.001), but there was no difference in diastolic blood pressure or heart rate.

Conclusions
Treatment with a single dose of nicotine immediately before emergence from anesthesia was associated with significantly lower reported pain scores during the first day after surgery. The decreased pain was associated with a reduction in morphine utilization and the analgesic effect of nicotine was not associated with hypertension or tachycardia.
Epinephrine Prevents Muscle Blood Flow Increases after Perineural Injection of Tetrodotoxin
Authors: Masuda Takako , Cairns Brian E. , Sadhasivam Senthilkumar , Dunning Patricia S. , Berde Charles B. 
Published: November 2004

Background
The local anesthetic properties of tetrodotoxin, a potent naturally occurring sodium channel blocker, have been recently reexamined. It was found that sciatic nerve block duration could be greatly increased and systemic toxicity greatly decreased if epinephrine was injected with tetrodotoxin. The mechanism that underlies epinephrine-mediated prolongation of tetrodotoxin nerve blocks is not known, but indirect evidence suggests that epinephrine may slow the clearance of tetrodotoxin from the site of injection. The authors hypothesized that tetrodotoxin causes vasodilatation at its injection site, which accelerates its systemic uptake, and that this vasodilatation is attenuated by coinjected epinephrine.

Methods
The radiolabeled microsphere technique was used to measure tissue blood flow in anesthetized rats before and after perisciatic injection of tetrodotoxin alone and in combination with epinephrine.

Results
Tetrodotoxin, in a dose of 0.1 ml of a 60 microM solution, significantly increased blood flow in perisciatic muscle at the injected side compared with simultaneous contralateral control and ipsilateral preinjection baseline. Tetrodotoxin did not increase blood flow in the sciatic nerve. Coinjection of epinephrine with tetrodotoxin prevented tetrodotoxin-induced increases in perisciatic muscle blood flow over time and did not alter sciatic nerve blood flow. Arterial blood pressure was maintained with this dose of tetrodotoxin, although brain blood flow decreased. Coinjection of epinephrine with tetrodotoxin prevented decreases in brain blood flow. Higher doses of tetrodotoxin produced hypotension.

Conclusions
Vasoconstriction in the perisciatic muscles by epinephrine may contribute to the prolongation of tetrodotoxin-induced sciatic nerve blocks and the reduction of systemic toxicity of tetrodotoxin.
ENVIRONMENTAL FACTORS AND SEXUAL EXPRESSION INCHLOROCOCCUM ECHINOZYGOTUM(CHLOROPHYCEAE)1
Authors: O'Kelley Joseph C. 
Published: November 2004

ABSTRACTSeveral environmental factors affected total growth and zygospore production inChlorococcum echinozygotumStarr. The temperature range at which zygospore production occurred was more restricted than the range that supported vegetative growth. Light intensity had little effect upon zygospore formation: gamete production and gamete pairing occurred in darkness. Zygospore production occurred over a wide pH range; bicarbonate had a minor effect upon zygospore formation. Nitrogen concentration was the factor of primary importance. As the level of nitrogen supplied as nitrate, ammonia, urea and asparagine in the medium was increased, zygospore production first increased (over no nitrogen) at low levels and then decreased at high levels. All levels of glutamine supplied reduced zygospore production. A possible way in which nitrogen concentration in the medium and sexual expression are linked is discussed.
FREEZE FRACTURE STUDY OF THYLAKOIDS OF FUCUS SERRATUS1
Authors: Berkaloff C. , Duval J. C. , Hauswirth N. , Rousseau B. 
Published: November 2004

ABSTRACTFreeze‐fractured thylakoids of Fucus serratus L. exhibit three types of faces with a particle density analogous to that of EFs, EFu and PF faces of green plants. However the particle size distribution is unimodal in the three types with a mean of about 8 nm. No obvious distinction between PFs and PFu faces could be detected. The absence on EFs faces of the distinct class of large particles (>13 nm) existing in green plant thylakoids implies a unique organization of pigment proteins, especially of the light‐harvesting complexes.
EFFECTS OF NITROGEN SOURCES ON P‐LIMITED GROWTH OF ANABAENA FLOS‐AQUAE1
Authors: Rhee G‐Yull , Lederman Timoth C. 
Published: November 2004

ABSTRACTThe effects of N2, nitrate and ammonia as N sources were investigated in P‐limited and nutrient‐sufficient cultures of Anabaena flos‐aquae (Lyngb.) Bréb. The maximum growth rate (μm) was highest at 1.34 d−1 with ammonia, compared to 1.18 with nitrate and 0.95 d−1 with N2. There was no difference in P requirement between N2 and nitrate cultures. Under P‐limited conditions, the increase in cell P with growth rate (μ) was identical. With N2 as the N source, cell‐N concentrations in P‐limited cells increased with μ as did cell P, and the cellular N:P ratio remained the same (14) within the range of μ examined. With nitrate, however, cell N concentrations were high and independent of n, except at a low μ. It appears that this organism fixes atmospheric N2 only at the minimum concentration required to maintain a μ. The acetylene reduction rate increased with μ in both N2‐ and nitrate‐grown cells, but the rate was lower in nitrate. Under P‐limitation, there was no difference in net C‐fixation rate per cell between N2 and nitrate cultures at a given μ. However, the rate per unit of chlorophyll a (chl a) was higher in N2 than in nitrate cultures, and the rate was independent of μ with N2 but was a linear function of nitrate supplied. The maximum C‐fixation rate in nutrient sufficient cells was highest with ammonia, followed by nitrate and N2. The cellular chl a concentration was correlated with the total cell‐N concentrations regardless of H and the source of N.
ULTRASTRUCTURE OF A FRESHWATER BROWN ALGA FROM WESTERN CANADA1
Authors: Pueschel Curt M. , Stein Janet R. 
Published: November 2004

ABSTRACT Heribaudiella fluviatilis (Aresch.) Sved. is a freshwater brown alga distributed in Europe and Japan, but known only from one questionable record in eastern North America. It is now reported as present in western Canada, approximately 250 km from any marine water. Ultrastructural features prove its phaeophycean character. Each cell contains several discoid chloroplasts with thylakoids in triplets and an encircling triplet adjacent to the chloroplast envelope. Voluminous osmiophilic substances presumed to be physodes (phenolics) are present, as well as a single nucleus associated with dictyosomes and a pair of centrioles. The cell walls are perforated by plasmodesmata, which are considered of importance in cohesion of filaments.
PHYSIOLOGICAL CHARACTERISTICS OF PHOTOSYNTHESIS IN PORPHYRIDIUM CRUENTUM: EVIDENCE FOR BICARBONATE TRANSPORT IN A UNICELLULAR RED ALGA1
Authors: Colman Brian , Gehl Katharina A. 
Published: November 2004

ABSTRACTVarious physiological characteristics of photosynthesis in the unicellular red alga Porphyridium cruentum Naegeli have been investigated. The rate of photosynthesis was optimal at 25° C and pH 7.5 and was not inhibited by 21% oxygen over a temperature range of 5 to 35° C. Kinetics of whole cell photosynthesis as a function of substrate concentration gave a K1/2, (CO2) of 0.3 μM. CO2 compensation point, measured in a closed system at pH 7.5, was a constant 6.7 &#x006d;̈L · L−1 over the temperature range 15 to 30° C and was unaffected by O2 concentration. Whole cell photosynthesis, measured in a closed system at alkaline pH, showed that the rates of oxygen evolution were greatly in excess of the rate of CO2 supply from the spontaneous dehydration of HCO3− in the medium. This indicates that bicarbonate is utilized by the cell to support this photosynthetic rate. These physiological characteristics of Porphyridium cruentum are consistent with the hypothesis that this alga transports bicarbonate across the plasmalemma.
CELL WALL STRUCTURE AND COMPOSITION AS TAXONOMIC CHARACTERS IN THE COCCOID CHLOROPHYCEAE1,2
Authors: Deason Temd R. 
Published: November 2004

ABSTRACTCell wall structure and composition of fifty‐one algae in the Volvocales, Tetrasporales, Chlorococcales, and Chlorosarcinales were investigated to determine the feasibility of using the presence of cellulose, wall fibers, and wall periodicity as taxonomic characters. Although members of the Volvocales consistently lack cellulose, the diversity of wall characters in the other orders discourages the use of these characters as taxonomic or phylogenetic criteria.
PHOTOSYNTHESIS, DARK RESPIRATION AND DESICCATION RESISTANCE OF THE INTERTIDAL SEAWEEDS HESPEROPHYCUS HARVEYANUS AND PELVETIA FASTIGIATA F. GRACILIS12
Authors: Oates Brian R. , Murray Steven N. 
Published: November 2004

ABSTRACTRates of net photosynthesis and dark respiration were determined under submersed and emerged conditions for Hesperophycus harveyanus S. & G. and Pelvetia fastigiata f. gracilis (Decne.) S. & G. Both species exhibited submersed photosynthesis‐light relationships and dark respiration rates similar to those established for other closely related intertidal, fucoids. Maximal net photosynthesis of H. harveyanus (0.21 mmol O2 g dry wt.‐1· h‐1; 0.18 mmol CO2 g dry wt.‐1· h‐1) was similar to that of P. fastigiata f. gracilis (0.17 mmol. O2 g dry wt.‐1· h‐1; 0.14 mmol CO2 g dry wt. ‐1· h‐1). Light saturation occurred between 150 and 250 μE · m‐2· s‐1 for H. harveyanus and between 75 and 150 μE · m‐2· s‐1 for P. fastigiata f. gracilis; photon flux densities required for compensation were 6.4 and 9.2 μE · m‐2· s‐1, respectively. Photoinhibition was not observed for either species. The light‐saturated, submersed net photosynthetic performances of both species varied significantly with temperature. Greatest photosynthetic rates were obtained at 23° C for H. harveyanus and at 18° C for P. fastigiata f. gracilis. Under emersed conditions, the maximal net photosynthetic rate and the photon flux densities required for saturation were greater for H. harveyanus (0.08 mmol CO2 g dry wt.‐1· h‐1; 260 to 700 μE · m‐2· s‐1) than for P. fastigiata f. gracilis (0.02 mmol CO2g dry wt.‐1· h‐1; 72 to 125 μE · m‐2· s‐1). However, for both species, emersed photosynthetic rates were much lower (14–44%) than those obtained under submersed conditions. Desiccation negatively influenced emersed photosynthesis, of both species, but H. harveyanus thalli contained more water when fully hydrated and lost water more slowly during dehydration, thus suggesting greater photosynthetic potential during field conditions of emersion.
SEASONAL DIFFERENCES IN THE TEMPERATURE RANGES OF GROWTH OF VIRGINIA ALGAE1
Authors: Seaburg Kenneth G. , Parker Bruce C. 
Published: November 2004

ABSTRACTOne hundred and fifteen clonal, unialgal strains were isolated and tested for their ability to grow over a range of temperatures from 2 to 40° C. Responses of 63 strains isolated from habitats that were 6° C when sampled and 52 strains isolated from habitats that were 20° C when sampled showed trends toward increasing adaptation to cold or warm temperatures commensurate with their seasonal in situ temperatures. Based on temperature‐growth responses alone, 24% of the plankton isolates and 17% of the periphyton isolates could be perennial within the natural habitats. At 5° C, 56% of the warm water plankton isolates and 48% of the warm water periphyton isolates were incapable of growth and, therefore, probably could not be important components of the winter algal community. Likewise at 25° C, 25% of the cold water plankton isolates and 13% of the cold water periphyton isolates were incapable of growth. Thus, temperature alone probably is an important variable regulating seasonal changes in algal community structure. Pollution of these habitats by a thermal enrichment averaging + 5° C year‐round could effect a pronounced change in algal species composition because many more taxa could be perennial and more taxa would be incapable of growth during naturally warm periods.