bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selective Postsynaptic Inhibition of Tonic-firing Neurons in Substantia Gelatinosa by μ-Opioid Agonist
Authors: Santos Sónia F. A. , Melnick Igor V. , Safronov Boris V. 
Published: October 2004

Background
Spinal substantia gelatinosa (SG) is a site of action of administered and endogenous opioid agonists and is an important element in the system of antinociception. However, little is known about the types of neurons serving as specific postsynaptic targets for opioid action within the SG. To study the spinal mechanisms of opioidergic analgesia, the authors compared the action of mu-opioid agonist [D-Ala, N-Me-Phe, Gly-ol]-enkephalin (DAMGO) on SG neurons with different intrinsic firing properties.

Methods
Whole cell patch clamp recordings from spinal cord slices of Wistar rats were used to study the sensitivity of SG neurons to DAMGO.

Results
Three groups of neurons with distinct distributions in SG were classified: tonic-, adapting-, and delayed-firing neurons. DAMGO at 1 microm concentration selectively hyperpolarized all tonic-firing neurons tested, whereas none of the adapting- or delayed-firing neurons were affected. The effect of DAMGO on tonic-firing neurons was due to activation of G protein-coupled inward-rectifier K conductance, which could be blocked by 500 microm Ba and 500 microm Cs but increased by 50 microm baclofen. As a functional consequence of DAMGO action, a majority of tonic-firing neurons changed their pattern of intrinsic firing from tonic to adapting.

Conclusions
It is suggested that tonic-firing neurons, presumably functioning as excitatory interneurons, are primary postsynaptic targets for administered and endogenous opioid agonists in spinal SG. Functional transition of cells in this group from tonic to adapting firing mode may represent an important mechanism facilitating opioidergic analgesia.
Mitochondrial Injury and Caspase Activation by the Local Anesthetic Lidocaine
Authors: Johnson Michael E. , Uhl Cindy B. , Spittler Karl-Heinz , Wang Hongxun , Gores Gregory J. 
Published: October 2004

Background
Lidocaine, a local anesthetic, can be neurotoxic. However, the cellular mechanisms of its neurotoxicity at concentrations encountered during spinal anesthesia remain unclear.

Methods
The authors examined the mechanisms of lidocaine neurotoxicity in the ND7 cell line derived from rat dorsal root ganglion. Individual neurons were assayed by flow cytometry or microscopy using fluorescent probes of plasma membrane integrity, mitochondrial membrane potential, caspase activity, phospholipid membrane asymmetry, and mitochondrial cytochrome c release.

Results
In the ND7 cell line, lidocaine at 185 mm x 10 min to 2.3 mm x 24 h caused necrosis or late apoptosis. Equimolar Tris buffer and equipotent tetrodotoxin controls were not toxic, indicating that neither osmotic nor Na-blocking effects explain lidocaine neurotoxicity. The earliest manifestation of lidocaine neurotoxicity was complete loss of mitochondrial membrane potential within 5 min after exposure to lidocaine at a concentration of 19 mm or greater. Consistent with these data, 37 mm lidocaine (1%) induced release of mitochondrial cytochrome c into the cytoplasm, as well as plasma membrane blebbing, loss of phosphatidylserine membrane asymmetry, and caspase activation, with release of mitochondrial cytochrome c to the cytoplasm within 2 h. Treatment with z-VAD-fmk, a specific inhibitor of caspases, prevented caspase activation and delayed but did not prevent neuronal death, but did not inhibit the other indicators of apoptosis.

Conclusions
Collectively, these data indicate that lidocaine neurotoxicity involves mitochondrial dysfunction with activation of apoptotic pathways.
Ultrasound-guided Lumbar Facet Nerve Block
Authors: Greher Manfred , Kirchmair Lukas , Enna Birgit , Kovacs Peter , Gustorff Burkhard , Kapral Stephan , Moriggl Bernhard 
Published: October 2004

Background
Lumbar facet nerve (medial branch) blocks are often used to diagnose facet joint-mediated pain. The authors recently described a new ultrasound-guided methodology. The current study determines its accuracy using computed tomography scan controls.

Methods
Fifty bilateral ultrasound-guided approaches to the lumbar facet nerves were performed in five embalmed cadavers. The target point was the groove at the cephalad margin of the transverse (or costal) process L1-L5 (medial branch T12-L4) adjacent to the superior articular process. Axial transverse computed tomography scans, with and without 1 ml contrast dye, followed to evaluate needle positions and spread of contrast medium.

Results
Forty-five of 50 needle tips were located at the exact target point. The remaining 5 were within 5 mm of the target. In 47 of 50 cases, the applied contrast dye reached the groove where the nerve is located, corresponding to a simulated block success rate of 94% (95% confidence interval, 84-98%). Seven of 50 cases showed paraforaminal spread, 5 of 50 showed epidural spread, and 2 of 50 showed intravascular spread. Despite the aberrant distribution, all of these approaches were successful, as indicated by contrast dye at the target point. Abnormal contrast spread was equally distributed among all lumbar levels. Contrast traces along the needle channels were frequently observed.

Conclusions
: The computed tomography scans confirm that our ultrasound technique for lumbar facet nerve block is highly accurate for the target at all five lumbar transverse processes (medial branches T12-L4). Aberrant contrast medium spread is comparable to that of the classic fluoroscopy-guided method.
Simultaneous Measurement and Integrated Analysis of Analgesia and Respiration after an Intravenous Morphine Infusion
Authors: Dahan Albert , Romberg Raymonda , Teppema Luc , Sarton Elise , Bijl Hans , Olofsen Erik 
Published: October 2004

Background
To study the influence of morphine on chemical control of breathing relative to the analgesic properties of morphine, the authors quantified morphine-induced analgesia and respiratory depression in a single group of healthy volunteers. Both respiratory and pain measurements were performed over single 24-h time spans.

Methods
Eight subjects (four men, four women) received a 90-s intravenous morphine infusion; eight others (four men, four women) received a 90-s placebo infusion. At regular time intervals, respiratory variables (breathing at a fixed end-tidal partial pressure of carbon dioxide of 50 mmHg and the isocapnic acute hypoxic response), pain tolerance (derived from a transcutaneous electrical acute pain model), and arterial blood samples were obtained. Data acquisition continued for 24 h. Population pharmacokinetic (sigmoid Emax)-pharmacodynamic models were applied to the respiratory and pain data. The models are characterized by potency parameters, shape parameters (gamma), and blood-effect site equilibration half-lives. All collected data were analyzed simultaneously using the statistical program NONMEM.

Results
Placebo had no systematic effect on analgesic or respiratory variables. Morphine potency parameter and blood-effect site equilibration half-life did not differ significantly among the three measured effect parameters (P > 0.01). The integrated NONMEM analysis yielded a potency parameter of 32 +/- 1.4 nm (typical value +/- SE) and a blood-effect site equilibration half-life of 4.4 +/- 0.3 h. Parameter gamma was 1 for hypercapnic and hypoxic breathing but 2.4 +/- 0.7 for analgesia (P < 0.01).

Conclusions
Our data indicate that systems involved in morphine-induced analgesia and respiratory depression share important pharmacodynamic characteristics. This suggests similarities in central mu-opioid analgesic and respiratory pathways (e.g., similarities in mu-opioid receptors and G proteins). The clinical implication of this study is that after morphine administration, despite lack of good pain relief, moderate to severe respiratory depression remains possible.
Introduction of Anesthesia Resident Trainees to the Operating Room Does Not Lead to Changes in Anesthesia-controlled Times for Efficiency Measures
Authors: Eappen Sunil , Flanagan Hugh , Bhattacharyya Neil 
Published: October 2004

Background
Operating room efficiency is an important concern in most hospitals today. Little work has been reported to evaluate the contribution of anesthesia residents to changes in anesthesia-controlled time-related efficiencies in the operating room. The goal of this study was to measure the impact of the initiation of new residents to the operating room on anesthesia-related time measures of operating room efficiency.

Methods
Using the computerized operating room information systems, specific data regarding anesthesia-controlled times were extracted over three distinct 2-week periods over the course of 1 academic year. These included the first 2 weeks of July, when most of the operating rooms were staffed by attending physicians working alone; 2 weeks in September when new anesthesia residents were working in a 2:1 ratio with staff; and 2 weeks in May. The induction times, emergence times, and room turnover times were compared over these three periods for first-year anesthesia residents. Standard descriptive statistics were computed. Analysis of variance testing was then conducted comparing each of these time periods. Significance was set at P < 0.05.

Results
A total of 3,004 surgical procedures were performed during the 2-week study periods in July, September, and May, respectively. For the July, September, and May groups, the mean anesthesia induction times were 17.3, 19.0, and 20.8 min (P = 0.047); the emergence times were 8.7, 9.7, and 10.0 min, (P = 0.024); and the corresponding mean room turnover times were 47.6, 48.5, and 48.6 min (P = 0.907), respectively.

Conclusion
Although statistically significant time differences were found, these data strongly suggest that the initiation of anesthesia trainees to the operating room has no clinically or economically meaningful adverse effect on the anesthesia-controlled time component of operating room efficiency.
CHEMICAL COMPOSITION AND PHOTOSYNTHETIC CHARACTERISTICS OF ETHMODISCUS REX (BACILLARIOPHYCEAE): EVIDENCE FOR VERTICAL MIGRATION1
Authors: Villareal Tracy A. , Carpenter Edward J. 
Published: October 2004

ABSTRACT Ethmodiscus rex (Rattray) Wiseman and Hendey cells from near surface net tows in the Southwest Atlantic Ocean and Caribbean Sea were examined for chemical composition, internal nutrient pool concentrations, and oxygen evolution characteristics. Elemental ratios indicated nitrogen limitation with C:N:P ratios of 125:9:1 (atoms), and carbon: chlorophyll (chl) ratios of 129:1 (weight). However, internal nitrate pools (1.4–27.1 mM) suggested that cells were not N‐limited. Intracellular NO3− accounted for up to 54% (range = 3–54%) of the total N quota in some samples. Photosynthetic parameters were consistent with a high‐light‐adapted population and suggested an instantaneous maximum chl‐specific photosynthetic rate (PBmax) of 4.8–12.4 nmol O2·μg chl−1· h−1. Respiration rates varied ten‐fold and were inversely related to PBmax Ethmodiscus chemical composition and buoyancy characteristics are similar to vertically migrating Rhizosolenia mats and the non‐motile dinoflagellate Pyrocystis noctiluca Murray (Schuett). The presence of internal NO3− pools in Ethmodiscus suggests that this genus is also vertically migrating to exploit sub‐surface nitrogen pools. Such behavior may be widespread in large, non‐motile oceanic phytoplankton. Based on ascent rate data, chemical composition, and photosynthetic rates, we estimate that the entire division–migration cycle for Ethmodiscus requires at least 7–12 days.
THE ACCLIMATED RESPONSE OF GROWTH, PHOTOSYNTHESIS, COMPOSITION, AND CARBON BALANCE TO TEMPERATURE IN THE PSYCHROPHILIC ICE DIATOM NITZSCHIA SERIATA1
Authors: Smith Ralph E. H. , Stapleford Lynn C. , Ridings Richard S. 
Published: October 2004

ABSTRACT Nitzschia seriata Cleve, a common member of marine bottom ice communities in the Arctic, was grown in unialgal batch cultures to test for compensatory mechanisms for the low temperatures (−1.8° C) typical of its natural habitat. The upper lethal limit for growth was between 12° and 15°C, and the optimum was between 6° and 12° C. The Arrhenius function adequately (R2= 73%) fitted the relationship between growth rate and temperature from – 1.6° up to 10° C, with an average Q10 of 1.9 over the entire range. Light‐saturated and light‐limited rates of photosynthesis (normalized to chlorophyll a or cell carbon) showed complete compensation from 12° to 4° C. Photosynthetic rates, especially at light saturation, declined rapidly at temperatures below 4° C. Susceptibility to photoinhibition was greatest at the lowest growth temperatures. Cellular composition (chlorophyll a, protein, polysaccharide, and lipid contents) was not systematically related to temperature in any simple way, although cell size (carbon per cell) was maximal at the lowest growth temperature. Dark respiration was unmeasurably low (<0.015 day−1) at all growth temperatures. The strategy of adaptation in N. seriata may be characterized as optimizing efficiency and compensation, rather than maximization, of growth rate.
RESPONSE OF CATALASE ACTIVITY TO ENVIRONMENTAL STRESS IN THE FRESHWATER DINOFLAGELLATE PERIDINIUM GATUNENSE1
Authors: Butow Barbara , Wynne David , Tel‐Or Elisha 
Published: October 2004

ABSTRACTCatalase activity increased in Peridinium gatunense (formerly P. cinctum fa. westii) cells during the decline of the seasonal spring bloom period in Lake Kinneret. This was correlated with the low ambient total CO2 concentration. The relationship was confirmed in laboratory experiments where maximum catalase activity occurred under an atmosphere composed of 30% O2 and 0.003% CO2. Conversely, high CO2 concentrations inhibited catalase activity. The rise in catalase activity was not directly due to increasing environmental pH, as in vitro and in vivo measurements showed a characteristic broad pH curve with a constant activity from pH 6–10 for catalase.Photoinhibition of catalase occurred above 250 μmol photons · m−2· s−1. However, at high photoinactivating irradiances, photoinhibition was ameliorated under high pO2/pCO2. Such conditions prevail in the Kinneret at the end of the spring. We propose that the enhancement of photorespiration (under high pO2/pCO2) induces a temporary burst in catalase activity despite the progressively photoinhibitory conditions of early summer.
CHLOROPLAST MICROTUBULES IN OEDOGONIUM CAPILLIFORME (CHLOROPHYTA)1
Authors: Ueda Katsumi , Kawaguchi Tomoko , Noguchi Tetsuko 
Published: October 2004

ABSTRACTMicrotubular elements in the chloroplasts (chl‐MTs) of Oedogonium capilliforme Wittrock were examined by conventional electron microscopy and immunoelectron microscopy. Chl‐MTs were frequently seen in the terminal, convex, and concave peripheral regions of the chloroplasts. Each bundle of chl‐MTs was composed of 2–25 tubular elements. Some chl‐MTs were located in the stroma. Chl‐MTs frequently bridged two areas of the envelope membrane near the apex of convex regions of chloroplasts. Some chl‐MTs were closely associated with the envelope membrane via apparent anchors along their length. The distribution patterns of chl‐MTs and their appearance suggest that chl‐MTs are involved in the maintenance of the outer shape of chloroplasts. However, immunoelectron microscopy with an antibody against α‐tubulin indicated that the chl‐MTs are not composed of tubulin.
ATTACHMENT AND FUSION OF GAMETES DURING FERTILIZATION OF PALMARIA SP. (RHODOPHYTA)1
Authors: Mine Ichiro , Tatewaki Masakazu 
Published: October 2004

ABSTRACTFertilization of cultured microscopic female gametophytes by spermatia from field‐collected male gametophytes of Palmaria sp. was observed by light and transmission electron microscopy. Liberated spermatia had a prophase‐arrested nucleus with a pair of polar rings. The protoplast of spermatia was covered with ca. a 3‐μm‐thick hyaline covering. After spermatium inoculation, the spermatial covering was attached specifically to the coat surrounding the cell wall of the trichogyne. The spermatial covering was eliminated only at the site of gamete attachment, resulting in direct attachment of the spermatial plasma membrane to the trichogyne within 5 min after spermatium inoculation. This direct attachment was followed by completion of spermatial nuclear division and cell wall formation. The polar rings disappeared before prometaphase. The cytoplasm of the binucleate spermatium invaded the trichogyne cell wall and subsequently fused with the trichogyne cytoplasm. The trichogyne could fuse with many spermatia, and many male nuclei (the derivative nuclei of spermatial nuclear division) could enter the trichogyne cytoplasm.
APPLICATION OF RAPD MARKERS IN AN EXAMINATION OF HETEROSIS IN GELIDIUM VAGUM (RHODOPHYTA)1
Authors: Patwary Mohsin U. , van der Meer John P. 
Published: October 2004

ABSTRACTFour morphologically indistinguishable isolates of monoecious Gelidium vagum Okamura were crossed reciprocally to obtain hybrids for a study on heterosis in this alga. Approximately 50% outcrossing was achieved by adding a small fragment of the designated female parent to a much larger quantity of designated male thallus in the crossing dish. Hybrids in the mixed population of isomorphic hybrid and inbred sporelings were identified by the presence of male‐specific random amplified polymorphic DNA markers. Growth performance of hybrid tetrasporophytes was compared to that of their gametophytic parents and with inbred tetrasporophytes at near‐optimum and sub‐optimum temperature and density. In general, the hybrids showed growth superiority over inbred lines, particularly under sub‐optimum conditions. In these experiments, the hybrid plants from cross 129 × 130 exhibited a 9.5–130% higher growth rate as compared to the mid‐value of the related inbred tetrasporophytes, strongly suggesting the presence of heterosis.
TWO SOLIERIACEAN ALGAE NEW TO THE MEDITERRANEAN: AGARDHIELLA SUBULATA AND SOLIERIA FILIFORMIS (RHODOPHYTA, GIGARTINALES)1
Authors: Perrone Cesira , Cecere Ester 
Published: October 2004

ABSTRACTTwo Atlantic species found in the Mediterranean Sea were ascribed to the family Solieriaceae on the basis of morphological features. In the extensive drifting beds of the Mar Piccolo basin (Taranto, Ionian Sea), Agardhiella subulata (C. Agardh) Kraft et Wynne and Solieria filiformis (Kützing) Gabrielson were the dominant species in summer. There were no attached populations, and perennation was ensured only by vegetative propagation. Characteristics of the outer cortex and chromatophores were useful for distinguishing the taxa at the species level and are recommended for recognition of sterile specimens.
DISTRIBUTION AND SYSTEMATICS OF BATRACHOSPERMUM (BATRACHOSPERMALES, RHODOPHYTA) IN NORTH AMERICA. 4. SECTION VIRESCENTIA1
Authors: Sheath Robert G. , Vis Morgan L. , Cole Kathleen M. 
Published: October 2004

ABSTRACTThirty‐nine populations of Batrachospermum section Virescentia from North America were compared to eight type specimens and two historically important specimens using multivariate morphometrics and image analysis. From this analysis, two species are recognized: B. helminthosum Bory de Saint‐Vincent (syn. B. bruziense Sirodot, B. graibussoniense Sirodot, B. sirodotii Skuja ex Flint, B. testale Sirodot, B. virgatum Sirodot nom. illeg., and B. viride Sirodot) and B. elegans Sirodot (syn. B. coerulescens Sirodot nom. illeg.). In B. helminthosum trichogynes are cylindrical to slightly club‐shaped with few to no protuberances, whereas in B. elegans half to all of the trichogynes have one to three basal knobs or branches. None of the qualitative features previously used to separate species in this section were found to be of taxonomic value due to their universal presence; quantitative characteristics were highly variable and overlapped among specimens examined. Emended descriptions of both species are provided. Batrachospermum elegans was collected in northeastern U.S.A. and central Costa Rica, whereas B. helminthosum ranged from Nova Scotia to Louisiana and was collected in central Mexico, Costa Rica, and northwestern U.S.A. Batrachospermum julianum Arcangeli and B. transtaganum Reis, previously classified in section Virescentia, were observed to have twisted carpogonial branches and, therefore, should be placed in section Contorta. Sections Setacea and Virescentia of Batrachospermum differ in whorl size, ratio of carposporophyte height to whorl diameter, and trichogyne stalking; hence, we continue to recognize them as being distinct taxonomic entities as originally described.
ULTRASTRUCTURE AND PHYLOGENETIC RELATIONSHIPS OF CHAETOPELTIDALES ORD. NOV. (CHLOROPHYTA, CHLOROPHYCEAE)1
Authors: O'Kelly Charles J. , Watanabe Shin , Floyd Gary L. 
Published: October 2004

ABSTRACTVegetative cells and zoospores of Hormotilopsis gelatinosa Trainor & Bold, H. tetravacuolaris Arce & Bold, Planophila terrestris Groover & Hofstetter, and Phyllogloea fimbriata (Korchikov) Silva were examined by transmission electron microscopy. All cells had pyrenoids traversed by cytoplasmic channels. Zoospores were quadriflagellate and had essentially cruciate flagellar apparatuses. Scales were present on free‐swimming zoospores. These features are essentially identical to those of Chaetopeltis sp. and are dissimilar to those of other described green algae. The new order Chaetopeltidales is created to accommodate the genera Chaetopeltis, Hormotilopsis, Planophila sensu Groover & Hofstetter, Phyllogloea, Dicranochaete, and Schizochlamys, organisms previously scattered among the orders Tetrasporales, Chloro‐coccales, Chlorosarcinales, and Chaetophorales. Members of the order are closely related to the ancestral chlorophycean flagellate genus Hafniomonas, may be ancestral with respect to other Chlorophyceae, and may also be closely related to the ulvophycean order Ulotrichales.