bluuebunny/crossref_metadata_2025 huggingface dataset:
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.
Making Management Decisions on the Day of Surgery Based on Operating Room Efficiency and Patient Waiting Times
Authors: Dexter Franklin , Epstein Richard H. , Traub Rodney D. , Xiao Yan , Warltier David C.
Published: November 2004

The authors review the scientific literature on operating room management operational decision making on the day of surgery. (1) Some decisions should rely on the expected (mean) duration of the scheduled case. Other decisions should use upper prediction bounds, lower prediction bounds, and other measures reflecting the uncertainty of case duration estimates. One single number cannot be used for good decision making, because durations are uncertain. (2) Operational decisions can be made on the day of surgery based on four ordered priorities. (3) Decisions to reduce overutilized operating room time rely on mean durations. Limited additional data are needed to make these decisions well, specifically, whether a patient is in each operating room and which cases are about to finish. (4) Decisions involving reducing patient (and surgeon) waiting times rely on quantifying uncertainties in case durations, which are affected highly by small sample sizes. Future studies should focus on using real-time display of data to reduce patient waiting.
Rural poverty in developing countries: an empirical analysis
Authors: Quang Dao Minh
Published: November 2004

This paper empirically analyzes the determinants of rural poverty in developing countries. Using data from a sample of 32 developing countries we are able to show that income redistribution in favor of the poorest 10 percent of the population, improving the productivity of agricultural workers, raising the economic and social status of women, especially of rural women, government policies aimed at reducing systemic discrimination against ethnic minorities, encouraging tourism where possible, and programs designed to assist the irrigation of croplands are called for in the quest for alleviating poverty in rural areas. As the extent of rural poverty is reduced, an added benefit is the deceleration of the rural‐urban migration process, which results in less pressure on government to provide additional spending on services such as sanitation, health, and education in urban areas as well as having to deal with a host of problems associated with overgrown cities such as a higher incidence of crime and of shanty towns on the outskirts of these cities.
ENVIRONMENTAL FACTORS AND SEXUAL EXPRESSION INCHLOROCOCCUM ECHINOZYGOTUM(CHLOROPHYCEAE)1
Authors: O'Kelley Joseph C.
Published: November 2004

Several 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

Freeze‐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

The 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

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

Various 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 m̈L · 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

Cell 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

Rates 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

One 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.
PROPERTIES OF PHOSPHOENOLPYRUVATE CARBOXYKINASE FROM ASCOPHYLLUM NODOSUM (PHAEOPHYCEAE)1
Authors: Kerby Nigel W. , Evans Leonard V.
Published: November 2004

Phosphoenolpyruvate carboxykinase was purified to electrophoretic homogeneity from the brown alga. Ascophyllum nodosum (L.) le Jol. Its molecular mass was 60 kDa as determined by gel filtration. The pH optimum of the carboxylating reaction was 7.9 and the apparent Km for PEP4, ADP and HCO3‐ were 0.036, 0.0116 and 50 mol · m‐3, respectively. Rates of light and dark carbon fixation are also reported for A. nodosum apices and it is shown that rates of in vitro PEPCK activity would account for the observed rate of dark fixation. The physiological role of PEPCK is discussed in relation to light‐independent carbon fixation.
HETEROMORPHIC LIFE‐HISTORY STRATEGIES IN THE BROWN ALGA SCYTOSIPHON LOMENTARIA (LYNGB.) LINK1
Authors: Littler Mark M. , Littler Diane S.
Published: November 2004

The adaptive significance of a life‐history strategy, expressed as divergent morphological forms, was examined for the heteromorphic alga Scytosiphon lomentaria. Successional studies were performed by physically clearing mature, temporally‐constant intertidal communities on San Clemente I., California. At week six, after clearing, complanate thalli dominated the successional plots (mean cover = 23.5%) and began to decline as the cylindrical form became abundant. The latter attained its peak cover (82.3%) at week 13, whereupon it too began a precipitous reduction. The crustose ralfsioid form appeared surprisingly early (4–13 wks) in trace amounts but did not achieve its greatest cover (85.0%) until week 43. The ranking from high to low primary productivity (cylindrical form = 8.1 mg C · g dry. wt‐1·h‐1, complanate form = 6.5 mg, crustose form = 0.5 mg) corresponded closely with the data for photosynthetic vs. structural components (cylindrical = 92.3% pigmented, complanate = 65.3%, crustose = 32.0%). This finding indicates that selection in the crust form, which is more readily accessible to epilithic grazers, has tended to increase allocation of materials to nonpigmented structural tissue at the expense of photosynthetic tissue and reduced production rates. The results for thallus losses to urchin grazing over 48 h were complanate form = 82.7% lost, cylindrical = 81.4% and crustose = 16.2%, which correlates with the calorific contents of the three forms (i.e. complanate = 4.97 kcal · ash‐free g dry wt.‐1, cylindrical = 4.46 kcal and crustose = 3.55 kcal). The crustose form had tougher thalli (26 g · mm‐2 to penetrate thallus) than either the complanate form (12 g) or the cylindrical form (15 g). It is likely that opposing selective factors have resulted in the evolutionary divergences observed in algae with heteromorphic life histories. Previous work may have overemphasized the selective role of grazing because the crustose form is also adapted to withstand physical forces (sand‐scouring, burial and wave‐shearing) or as an overwintering stage under physiologically stressful conditions.
THE BOTTOM‐ICE MICROALGAL COMMUNITY FROM ANNUAL ICE IN THE INSHORE WATERS OF EAST ANTARCTICA1
Authors: McConville Malcolm J. , Wetherbee Richard
Published: November 2004

The structure, productivity and heterotrophic potential of an extensive microalgal community growing on the underside of sea ice near the Australian Antarctic Station of Casey, are described. Underwater observations made near the Australian Antarctic stations of Davis and Mawson are also reported. This community develops during September, is largely suspended from the bottom surface of annual sea ice and often extends into the underlying water column as conspicuous strands up to 15 cm long. The algal community structure in the strands is dominated by an unidentified tube diatom belonging to the Amphipleura/Berkeleya group and chains of a species of Entomoneis cf. Amphiprora paludosa var. hyperborea (Grunow) Cleve. Unlike previously described bottom ice environments, a brash ice layer under the hard sea ice is absent. Living cells, predominantly Nitzschia frigida Grunow, also occur in microbrine channels in the bottom 3 cm of the ice. Maximal primary production rates of 81 μg C · L‐1· h‐1 occurred during November, then began declining near the end of December. Minimal rates (2.8 μg C · L‐1· h‐1) were reached in mid‐January and coincided with changes in the physical structure of the sea ice and in the stability of the water column. An abundant epibacterial community associated with the microalgal strands assimilated 3H‐labelled amino acids suggesting significant heterotrophic recycling of dissolved organic matter. Turnover times of assimilated amino acids in the bottom ice community averaged 55 h during November while negligible turnover of these substrates occurred in the water column 1.5 m below the ice. These bottom ice communities have higher primary productivity than typical brash ice communities; they are also accessible to marine herbivores and so may be more important to the Antarctic marine food chain than previously supposed.
THE GENUS ACTINOCYCLUS (BACILLARIOPHYCEAE): FRUSTULE MORPHOLOGY OF A. SAGITTULUS SP. NOV. AND TWO RELATED SPECIES1
Authors: Villareal Tracy A. , Fryxell Greta A.
Published: November 2004

Actinocyclus octonarius var. tenellus (Bréb.) Hendey, A. actinochilus (Ehr.) Simonsen and A. sagittulus sp. nov. were examined by light and scanning electron microscopy from field samples and/or culture material. Consistent cingulum patterns of a wide valvocopula and one narrow pleura were found. In A. actinochilus, a small third band was found filling the opening of the pleura and is probably present in the other two taxa. The observed variability of the pseudonodulus, especially in A. actinochilus but also in other members of the genus, was confirmed and our results support the literature definition of Actinocyclus as having: 1) a marginal ring of large labiate processes, laterally expanded internally, 2) no external tubes, 3) essentially radial areolation arranged in fascicles, 4) external cribrum, internal foramen, and 5) a pseudonodulus usually present, but may be absent or difficult to detect on individual valves. On the basis of the present study another characteristic should be added; 6) hyaline bands with a wide valvocopula and at least one pleura. This characteristic appears to extend throughout the family Hemidiscaceae, suggesting a close relationship to those Coscinodiscus species with a single marginal row of large labiate processes and zero or one central labiate processes. In addition, Actinocyclus has been noted to have a thin valve overhang extending outside the valvocopula for as much as one‐third of its width.
Fiscal Structure and the Post‐Proposition 13 Fiscal Regime in California's Cities
Authors: Hoene Christopher
Published: November 2004

Two and a half decades after the passage of Proposition 13 in 1978, California state and local governments continue to feel the intended and unintended effects of tax and expenditure limitations. While considerable time has passed since voters enacted Proposition 13, the effects of the property tax revolt continue to be dramatic. This article examines the fiscal structure of California's city governments from 1972 to 2002. The analysis reveals that California's cities have become less reliant upon property tax revenues and more reliant upon charges and fees, and have not increased reliance upon sales tax revenues as much as expected.
Vox Populi? Oregon Tax and Expenditure Limitation Initiatives
Authors: Thompson Fred , Green Mark T.
Published: November 2004

This article provides a brief history of tax and expenditure limitation initiatives in Oregon, along with a narrative of contemporary events. Largely as a consequence of the initiative's increased role in the formulation of Oregon's fiscal policy, state and local taxes paid by Oregon households declined from 7.4 percent of income in 1989 to 6.8 percent in 2003; state revenue, which is heavily dependent upon personal income taxes, has become increasingly income elastic; and state and local governments now rely on user fees to an almost unprecedented degree.
Can competition explain local rarity of a nettle aphid?
Authors: Kean John M. , Müller Christine B.
Published: November 2004

Abstract.  1. Previous studies have shown that two aphid species, Microlophium carnosum and Aphis urticata on stinging nettle (Urtica dioica) show very different abundance patterns.

2. Theory suggests that the local rarity of A. urticata in Silwood Park, U.K., might be explained by competitive exclusion by the more common species, mediated indirectly through natural enemies. Experimental aphid colonies on potted nettles were used to test for effects of M. carnosum on A. urticata in the field.

3. Though there was some evidence that natural enemies aggregated on the aphid colonies, no population‐level effects of competition from M. carnosum on A. urticata could be detected. No evidence was found for competition being a major factor causing the local rarity of A. urticata.
Persistence and regression of hearing in the exclusively diurnal moths, Trichodezia albovittata (Geometridae) and Lycomorpha pholus (Arctiidae)
Authors: Muma Katherine E. , Fullard James H.
Published: November 2004

Abstract.  1. Auditory sensitivities and ultrasound avoidance behaviour of two exclusively diurnal moths were examined to test the prediction that total isolation from the predatory effects of echolocating bats will result in the regression of these sensory systems and/or the defences they evoke.

2. The silent geometrid, Trichodezia albovittata, possessed large ears with auditory neural thresholds similar to or better than those of a sympatric, exclusively nocturnal geometrid moth. Trichodezia albovittata readily responded with evasive flight to ultrasound and it is suggested that if this moth has become completely isolated from bats its ears are functionally vestigial, at least in the population studied here.

3. In contrast, while the sound‐producing arctiid, Lycomorpha pholus, had low auditory sensitivity based on neural thresholds, it still responded with flight changes to ultrasound. It did not, however, produce sounds when stimulated ultrasonically. It is suggested that the ears of this moth are functionally vestigial for bat‐detection purposes but may be used for short‐distance social communication.
Laughing, Tickling, and the Evolution of Speech and Self
Authors: Provine Robert R.
Published: November 2004

Laughter is an instinctive, contagious, stereotyped, unconsciously controlled, social play vocalization that is unusual in solitary settings. Laughter punctuates speech and is not typically humor related, speakers often laugh more often than their audience, and male speakers are the best laugh getters. Laughter evolved from the labored breathing of physical play, with the characteristic “pant-pant” laugh of chimpanzees and derivative “ha-ha” of humans signaling (“ritualizing”) its rowdy origin. Laughter reveals that breath control is why humans can speak and chimpanzees cannot. The evolution of bipedality in human ancestors freed the thorax of its support role in quadrupedal locomotion, a critical step in uncoupling breathing from running, providing humans with the flexible breath control necessary for speech and our characteristic laugh. Tickle, an ancient laughter stimulus, is a means of communication between preverbal infants and mothers, and between friends, family, and lovers. Because you cannot tickle yourself, tickle involves a neurological self/nonself discrimination, providing the most primitive social scenario.
Serotonin reuptake inhibitor induced sensory disturbances
Authors: Praharaj Samir K.
Published: November 2004

Serotonin reuptake inhibitor induced sensory disturbances are reported rarely in the literature. This case report describes numbness and dysmorphic symptoms in the upper facial area associated with fluoxetine. There is no previous report of such an adverse reaction with any serotonin reuptake inhibitor in the literature and this report is intended to draw attention towards these unusual adverse effects.
Prescribing for osteoporosis following the use of inhaled and oral glucocorticoids in general practice
Authors: Williams David , Bennett Kathleen , Feely John
Published: November 2004

Aims  Systemic absorption from inhaled glucocorticoids may lead to bone loss. We determined the extent to which their use alone and in addition to short courses of oral glucocorticoids was associated with increased prescribing for osteoporosis in a large general practice population.

Methods  In a cohort study with follow‐up of co‐prescribing of antiosteoporotic drug therapy in the Irish national prescribing database (1.1 million people over 16 years), we identified 32 081 patients who received inhaled glucocorticoids alone during a 12‐month period (following an identical lead‐in period). We determined the odds ratio (OR), adjusting for age and gender for the co‐prescription of bisphosphonates or other antiosteoporotic therapy with inhaled glucocorticoids by logistic regression.

Results  The adjusted OR (95% confidence interval) for co‐prescribing of bisphosphonates and all inhaled glucocorticoids was 1.87 (1.71, 2.04); 1.58 (1.41, 1.78) for inhaled beclomethasone, 2.11 (1.75, 2.54) for inhaled budesonide and 3.29 (2.65, 4.1) for inhaled fluticasone. The ORs were significantly increased when patients who also received oral glucocorticoids were included and greater still in those under 45 years: 14.03 (10.6, 18.6). The results remained significant when the effects of comorbidity were adjusted for. The odds of receiving bisphosphonate therapy increased linearly with increasing exposure to inhaled glucocorticoids during the study period.

Conclusions  Treatment with inhaled glucocorticoids in general practice is associated with an increased risk of co‐prescribing for antiosteoporotic therapy in a potency‐ and a dose‐related manner. Exposure to a course of oral glucocorticoids doubles this risk. These results suggest that the systemic effects on bone mineral density from using inhaled glucocorticoids may be clinically relevant but may also reflect prescribers’ concerns for the development of osteoporosis in these patients.
Operational nitrogen fertilizer management in dairy farming systems: identification of criteria and derivation of fertilizer application rates
Authors: Vellinga Th. V. , André G. , Schils R. L. M. , Oenema O.
Published: November 2004

Fertilizer‐nitrogen (N) management is a decisive factor in grass‐based, intensive dairy farming, as it strongly influences economic and environmental performance but little attention has been paid to providing guidance on N‐fertilizer management at an operational level to meet these criteria of performance. Essential criteria in operational N‐fertilizer management were identified as target dry matter (DM) yield of herbage, growth period per cut, herbage N concentration, N use efficiency (NUE), amounts of unrecovered N and marginal N response. Statistical relationships between fertilizer‐N application rates per cut and these criteria were derived from field experiments. These relationships were then used to explore the effects of the criteria on optimum fertilizer‐N applications.

Optimum fertilizer‐N rates depended strongly on target levels for NUE, amounts of unrecovered N, growth period and DM yield of herbage. Calculations showed that target DM yield of herbage and growth period per cut are essential in estimating the effect of applied N on marginal N response, NUE and amounts of unrecovered N. The derived relationships can be used to explore the effects of changes in target levels of the criteria on optimum fertilizer‐N applications. The study showed that operational fertilizer‐N management set constraints to the decisions made at strategic and tactical management levels and vice versa.
Nodulation and root growth of forage legumes sown into tall fescue swards
Authors: Staley T. E. , Belesky D. P.
Published: November 2004

Establishing forage legumes into endophyte‐infected tall fescue (Festuca arundinacaeSchreb.) pastures is problematic, especially in well‐established stands. A oversowing field experiment determined if this problem was because of poor nodulation. Four renovation techniques, clipped sward (treatment A), herbicided + rye seeding in the previous autumn (treatment B), herbicided in the autumn and spring (treatment C) and herbicided to suppress the sward (treatment D), were investigated to determine their effect on nodulation and root growth of lucerne (Medicago sativaL.), red clover (Trifolium pratenseL.) and white clover (T. repensL.) at 16, 22 and 29 d after sowing the legumes. A pot experiment was also conducted under optimal growth conditions and using the same soil to determine the nodulation and root growth potentials of these legume species. At adequate rhizobial populations (>6 × 104 cfu g−1soil), substantial nodulation of all species occurred by 29 d after sowing in treatments C and D, whereas nodulation of clovers was usually reduced in treatment A. Total root lengths for all sampling dates, species and treatments were severely restricted, especially under treatment A. A general correspondence of nodulation with root growth was observed for all species, with high correlations (r ≥ 0·85) between these variables for all legume species and treatments, suggesting that soil moisture, and possibly competition for light, were the limiting factors. These results demonstrate that weak stands of forage legumes, typically found when sown into tall fescue swards, are probably not because of inadequate nodulation. Rather, inhibition of root growth by detrimental physical/chemical conditions or allocation of limited photosynthate to shoots instead of roots is suggested.
Genetic mapping of dominant white (W), a homozygous lethal condition in the horse (Equus caballus)
Authors: Mau C. , Poncet P. A. , Bucher B. , Stranzinger G. , Rieder S.
Published: November 2004

Dominant white coat colour (W) is a depigmentation syndrome, known in miscellaneous species. When homozygous in the horse (similar in mice), the mutation responsible for the white phenotype is lethal in a very early stage of gestation. It seems, that the action of the dominant white allele is not always fully penetrant, resulting occasionally in spotted look alike offspring. These horses resemble a coat colour pattern known as sabino spotting. So far, it is not known whether dominant white (W) and sabino spotting (S) share a common genetic background. In this study, a pedigree consisting of 87 horses segregating for dominant white (W) was used to genetically localize the horse (W)‐locus. Microsatellite ASB23 was found linked to (W), which allowed us to map dominant white to a region on horse chromosome 3q22. Tyrosine kinase receptor (KIT) was previously mapped to this same chromosome region (3q21–22). KIT and its ligand (KITLG) are responsible for the normal function of melanogenesis, haematopoiesis and gametogenesis. So far, sequence analysis of different KIT gene fragments did not lead to new polymorphisms, except for a SNP detected in KIT intron 3 (KITSNPIn3). Additional microsatellites from ECA3q (TKY353 and LEX7), together with KITSNPIn3 allowed us to state more precisely the (W)‐mutation. The positional results and comparative functional data strongly suggest that KIT encodes for the horse (W)‐locus.
Studies of the Ala/Val98 polymorphism of the hepatocyte nuclear factor‐1α gene and the relationship to β‐cell function during an OGTT in glucose‐tolerant women with and without previous gestational diabetes mellitus
Authors: Lauenborg J. , Damm P. , Ek J. , Glümer C. , Jørgensen T. , Borch‐Johnsen K. , Vestergaard H. , Hornnes P. , Pedersen O. , Hansen T.
Published: November 2004

Aims  In pregnancies complicated by gestational diabetes mellitus (GDM) an increased demand for insulin is not met due to β‐cell dysfunction. An Ala/Val polymorphism at codon 98 of the hepatocyte nuclear factor‐1α (HNF‐1α) gene has been associated with decreased serum insulin and C‐peptide responses during an oral glucose tolerance test (OGTT) in glucose‐tolerant subjects. The aims of the present study were to evaluate the influence of the polymorphism on the serum insulin and C‐peptide responses to an OGTT in glucose‐tolerant women with and without previous GDM and to investigate if this polymorphism is associated with GDM.

Methods  The Ala/Val98 polymorphism was measured in 376 women of Danish origin with previous GDM, and in 724 age‐matched and 310 middle‐aged glucose tolerant women using polymerase chain reaction‐restriction fragment length polymorphism.

Results  The allelic frequency of the Ala/Val98 polymorphism was 0.043 [95% confidence interval (CI) 0.028, 0.057] in women with previous GDM vs. 0.037 (95% CI 0.028, 0.047) in age‐matched and 0.039 (95% CI 0.024, 0.054) in middle‐age women. Among 117 glucose‐tolerant women with previous GDM, 10 carriers of the Ala/Val98 polymorphism had a non‐significant 27% and 22% reduction in serum C‐peptide and insulin levels, respectively, at 30 min during an OGTT. Seventy‐eight control subjects carrying the Ala/Val98 polymorphism had a 10% (P = 0.001) and 16% (P = 0.004) reduction in serum C‐peptide and insulin levels, respectively, compared with 956 Ala/Ala control subjects.

Conclusions  The Ala/Val polymorphism at codon98 of HNF‐1α is not associated with GDM in Danish women. However, the codon 98 variant is associated with a significant impairment of serum insulin and C‐peptide responses during an OGTT in glucose‐tolerant women without previous GDM.
Erythromelia, or Mitchell's syndrome – new names for unexplained signs of inflammation in distal symmetrical neuropathy in diabetes
Authors: Jeffcoate W. J. , Idris I. , Game F. L.
Published: November 2004

Background  Two cases are described in which distal symmetrical sensorimotor neuropathy complicating diabetes was associated with episodes of subacute vasodilation of one or other lower limb, and which were otherwise unexplained. The vasodilation was associated with swelling and stiffness, but was painless and self‐limiting.

Interpretation  It is suggested that this phenomenon results from disordered vasoregulation in diabetic neuropathy, and is linked to the processes which underlie diabetic neuropathic osteoarthropathy (Charcot foot), as well as disorders such as complex regional pain syndrome‐1 (CRPS‐1, reflex sympathetic dystrophy) and erythromelalgia.

Conclusions  As self‐limiting vasodilation may be not uncommon in distal symmetrical neuropathies, but unrecognized because the phenomenon has not been named, the terms ‘neuropathic erythromelia’ or ‘Mitchell's syndrome’ are proposed. The adoption of either of these names may lead to earlier diagnosis and prevent inappropriate investigation and treatment.
Oxidative stress and glucose levels in a population‐based sample
Authors: Menon V. , Ram M. , Dorn J. , Armstrong D. , Muti P. , Freudenheim J. L. , Browne R. , Schunemann H. , Trevisan M.
Published: November 2004

Objectives  To examine the relationship between markers of oxidative status and glucose on a population basis.

Study design and setting  We report here on a population‐based sample of 1315 women and 981 men, aged 35–79 years, randomly selected from residents of Erie and Niagara Counties in western New York between 1996 and 1999. Thiobarbituric reactive substances (TBARS), erythrocyte glutathione (GSH) and plasma glutathione peroxidase (GSH‐Px) were measured as markers of oxidative status. Study sample was categorized by quartiles of glucose, degree of abnormality of fasting glucose, and level of metabolic control in patients with diabetes.

Results  Men and women in the uppermost quartiles of glucose had higher levels of TBARS (men: Quartile 4 = 1.55 ± 0.03, Quartile 1 = 1.36 ± 0.03, women: 1.49 ± 0.02, 1.30 ± 0.02 nmol/ml) and lower levels of GSH (men: Quartile 4 = 1.57 ± 0.03, Quartile 1 = 1.69 ± 0.03, women: 1.71 ± 0.03, 1.97 ± 0.0 mmol/l packed RBCs). In women, compared with normal fasting glucose, impaired fasting glucose was associated with higher levels of TBARS (1.29 ± 0.01 vs. 1.84 ± 0.04 nmol/ml), lower levels of GSH (1.85 ± 0.02 vs. 1.76 ± 0.05 mmol/l packed RBCs), and higher GSH‐Px activity (618.94 ± 2.64 vs. 644.77 ± 8.90 IU/l). In women, abnormal fasting glucose was associated with higher levels of TBARS (1.84 ± 0.04 nmol/ml), lower levels of GSH (1.68 ± 0.06 mmol/l packed RBCs), and higher levels of GSH‐Px (647.72 ± 9.87 IU/l) than normal or impaired fasting glucose. In men, abnormal fasting glucose was associated with higher TBARS (1.76 ± 0.04 vs. 1.37 ± 0.07 nmol/ml), and lower GSH (1.62 ± 0.05 vs. 2.78 ± 0.02 mmol/l packed RBCs), than normal fasting glucose. Poor metabolic control was associated with higher TBARS (men: 2.07 ± 0.08 vs. 1.33 ± 0.14 nmol/l, women: 2.02 ± 0.09 vs. 1.35 ± 0.18 nmol/l) and GSH‐Px activity (men: 654.34 ± 13.45 vs. 599.86 ± 24.76, women: 660.61 ± 13.25 vs. 579.42 ± 27.42 IU/l).

Conclusions  Glucose levels play a role in determining oxidative status in a population sample. The balance between oxidative and antioxidant processes appears to be sensitive to glucose levels with moderate elevations of glucose affecting the oxidative status.