bluuebunny/crossref_metadata_2025_split huggingface dataset:
The catch state of mollusc catch muscle is established during activation:experiments on skinned fibre preparations of the anterior byssus retractor muscle of Mytilus edulis L. using the myosin inhibitors orthovanadate and blebbistatin
Authors: Andruchov Oleg , Andruchova Olena , Galler Stefan 
Published: October 2006

SUMMARY
Catch is a holding state of muscle where tension is maintained passively for long time periods in the absence of stimulation. The catch state becomes obvious after termination of activation; however, it is possible that catch linkages are already established during activation. To investigate this,skinned fibre bundles of the anterior byssus retractor muscle of Mytilus edulis were maximally activated with Ca2+ and subsequently exposed to 10 mmol l-1 orthovanadate (Vi) or 5 μmol l-1 blebbistatin to inhibit the force-generating myosin head cross-bridges. Repetitive stretches of about 0.1% fibre bundle length were applied to measure stiffness. Inhibitor application depressed force substantially but never resulted in a full relaxation. The remaining force was further decreased by moderate alkalization (change of pH from 6.7 to 7.4) or by cAMP. Furthermore, the stiffness/force ratio was higher during exposure to Vi or blebbistatin than during partial Ca2+ activation producing the same submaximal force. The increased stiffness/force ratio was abolished by moderate alkalization or cAMP. Finally, the stretch-induced delayed force increase (stretch activation) disappeared, and the force recovery following a quick release of the fibre length, was substantially reduced when the force was depressed by Vi or blebbistatin. All these findings suggest that catch linkages are already established during maximal Ca2+ activation. They seem to exhibit ratchet properties because they allow shortening and resist stretches. In isometric experiments a force decrease is needed to stress the catch linkages in the high resistance direction so that they contribute to force.
Antioxidant protection, carotenoids and the costs of immune challenge in greenfinches
Authors: Hõrak Peeter , Zilmer Mihkel , Saks Lauri , Ots Indrek , Karu Ulvi , Zilmer Kersti 
Published: October 2006

SUMMARYCosts accompanying immune challenges are believed to play an important role in life-history trade-offs and warranting the honesty of signal traits. We performed an experiment in captive greenfinches (Carduelis chlorisL.) in order to test whether and how humoral immune challenge with non-pathogenic antigen [sheep red blood cells (SRBC)] affects parameters of individual condition including intensity of coccidian infection, estimates of total antioxidant protection, plasma carotenoids and ability to mount a cell-mediated immune response. We also asked whether the potential costs of immune challenge can be alleviated by dietary carotenoid supplementation. None of the treatments affected intensity of coccidiosis. Humoral immune challenge suppressed the cell-mediated response to phytohemagglutinin (PHA), suggesting a trade-off between the uses of different arms of the immune system. Immune challenge reduced body-mass gain, but only among the carotenoid-depleted birds, indicating that certain somatic costs associated with immune system activation can be alleviated by carotenoids. No evidence for oxidative stress-induced immunopathological damages could be found because immune activation did not affect total antioxidant protection or carotenoid levels. Carotenoid supplementation inclined birds to fattening, indicating that lutein interfered with lipid metabolism. Altogether, our results support the hypotheses of biological importance of carotenoids and exemplify the overwhelming complexity of their integrated ecophysiological functions.
Extreme diving of beaked whales
Authors: Tyack Peter L. , Johnson Mark , Soto Natacha Aguilar , Sturlese Albert , Madsen Peter T. 
Published: October 2006

SUMMARYSound-and-orientation recording tags (DTAGs) were used to study 10 beaked whales of two poorly known species, Ziphius cavirostris (Zc) and Mesoplodon densirostris (Md). Acoustic behaviour in the deep foraging dives performed by both species (Zc: 28 dives by seven individuals; Md: 16 dives by three individuals) shows that they hunt by echolocation in deep water between 222 and 1885 m, attempting to capture about 30 prey/dive. This food source is so deep that the average foraging dives were deeper (Zc: 1070 m; Md:835 m) and longer (Zc: 58 min; Md: 47 min) than reported for any other air-breathing species. A series of shallower dives, containing no indications of foraging, followed most deep foraging dives. The average interval between deep foraging dives was 63 min for Zc and 92 min for Md. This long an interval may be required for beaked whales to recover from an oxygen debt accrued in the deep foraging dives, which last about twice the estimated aerobic dive limit. Recent reports of gas emboli in beaked whales stranded during naval sonar exercises have led to the hypothesis that their deep-diving may make them especially vulnerable to decompression. Using current models of breath-hold diving, we infer that their natural diving behaviour is inconsistent with known problems of acute nitrogen supersaturation and embolism. If the assumptions of these models are correct for beaked whales,then possible decompression problems are more likely to result from an abnormal behavioural response to sonar.
Air-flow sensitive hairs: boundary layers in oscillatory flows around arthropod appendages
Authors: Steinmann T. , Casas J. , Krijnen G. , Dangles O. 
Published: October 2006

SUMMARYThe aim of this work is to characterize the boundary layer over small appendages in insects in longitudinal and transverse oscillatory flows. The problem of immediate interest is the early warning system in crickets perceiving flying predators using air-flow-sensitive hairs on cerci, two long appendages at their rear. We studied both types of oscillatory flows around small cylinders using stroboscopic micro-particle image velocimetry as a function of flow velocity and frequency. Theoretical predictions are well fulfilled for both longitudinal and transverse flows. Transverse flow leads to higher velocities than longitudinal flow in the boundary layer over a large range of angles between flow and cylinder. The strong spatial heterogeneity of flow velocities around filiform-shaped appendages is a rich source of information for different flow-sensing animals. Our results suggest that crickets could perceive the direction of incoming danger by having air-flow-sensitive hairs positioned around their entire cerci. Implications for biomimetic flow-sensing MEMS are also presented.
The interactive effects of hypoxia and nitric oxide on catecholamine secretion in rainbow trout (Oncorhynchus mykiss)
Authors: McNeill Brian , Perry Steve F. 
Published: October 2006

SUMMARYExperiments were performed to test the hypothesis that exposure of rainbow trout to repetitive hypoxia would result in a decreased capacity of chromaffin cells to secrete catecholamines owing to increased production of nitric oxide(NO), a potent inhibitor of catecholamine secretion. A partial sequence of trout neuronal nitric oxide synthase (nNOS) was cloned and its mRNA was found to be present in the posterior cardinal vein (PCV), the predominant site of chromaffin cells in trout. Using heterologous antibodies, nNOS and endothelial NOS (eNOS) were localized in close proximity to the chromaffin cells of the PCV.Exposure of trout to acute hypoxia (5.33 kPa for 30 min) in vivoresulted in significant increases in plasma catecholamine and NO levels. However, after 4 days of twice-daily exposures to hypoxia, the elevation of plasma catecholamine levels during hypoxia was markedly reduced. Associated with the reduction in plasma catecholamine levels during acute hypoxia was a marked increase in basal and hypoxia-evoked circulating levels of NO that became apparent after 2-4 days of repetitive hypoxia. The capacity of the chromaffin cells of the hypoxia-exposed fish to secrete catecholamine was assessed by electrical stimulation of an in situ saline-perfused PCV preparation. Compared with control (normoxic) fish, the PCV preparations derived from fish exposed to repeated hypoxia displayed a significant reduction in electrically evoked catecholamine secretion that was concomitant with a marked increased in NO production. This additional rise in NO secretion in preparations derived from hypoxic fish was prevented after adding NOS inhibitors to the perfusate; concomitantly, the reduction in catecholamine secretion was prevented. The increased production of NO during hypoxia in vivo and during electrical stimulation in situ was consistent with significant elevations of nNOS mRNA and protein; eNOS protein was unaffected. These results suggest that the reduced capacity of trout chromaffin cells to secrete catecholamines after repeated hypoxia reflects an increase in the expression of nNOS and a subsequent increase in NO production during chromaffin-cell activation.
Repeated cocaine effects on learning, memory and extinction in the pond snail Lymnaea stagnalis
Authors: Carter Kathleen , Lukowiak Ken , Schenk James O. , Sorg Barbara A. 
Published: October 2006

SUMMARY
The persistence of drug addiction suggests that drugs of abuse enhance learning and/or impair extinction of the drug memory. We studied the effects of repeated cocaine on learning, memory and reinstatement in the pond snail, Lymnaea stagnalis. Respiratory behavior can be operantly conditioned and extinguished in Lymnaea, and this behavior is dependent on a critical dopamine neuron. We tested the hypothesis that repeated cocaine exposure promotes learning and memory or attenuates the ability to extinguish the memory of respiratory behavior that relies on this dopaminergic neuron. Rotating disk electrode voltammetry revealed a Km and Vmax of dopamine uptake in snail brain of 0.9 μmol l-1 and 558 pmol s-1 g-1 respectively, and the IC50 of cocaine for dopamine was approximately 0.03 μmol l-1. For operant conditioning, snails were given 5 days of 1 h day-1 immersion in water (control) or 0.1 μmol l-1cocaine, which was the lowest dose that maximally inhibited dopamine uptake,and snails were trained 3 days later. No changes were found between the two groups for learning or memory of the operant behavior. However, snails treated with 0.1 μmol l-1 cocaine demonstrated impairment of extinction memory during reinstatement of the behavior compared with controls. Our findings suggest that repeated exposure to cocaine modifies the interaction between the original memory trace and active inhibition of this trace through extinction training. An understanding of these basic processes in a simple model system may have important implications for treatment strategies in cocaine addiction.
Use of urea as a chemosensory cloaking molecule by a bony fish
Authors: Barimo John F. , Walsh Patrick J. 
Published: October 2006

SUMMARY
Because urea is bioenergetically expensive to synthesize, few aquatic teleostean (bony) fish make or excrete much urea beyond early development and excrete the majority of nitrogenous waste as the readily diffusible ammonia. The gulf toadfish is one of a few adult teleostean fish that excretes predominately urea. Most studies of chemosensing by fish predators have focused on amino acids as odorants, but we tested the chemo-attractiveness of both urea and ammonia. We report that characteristic `prey-attack' behaviors by a key toadfish predator, gray snapper, were elicited by low ammonia concentrations (&lt;100 nmol N l-1) and similar urea concentrations blunted the ammonia-induced component of attacks. Thus, urea functions as a cloaking molecule, explaining why toadfish co-excrete urea with ammonia. Furthermore, ammonia waste is an important chemical attractant for piscine predators.
Calculation procedure for time-dependent deforming interfaces in multi-fluid systems
Authors: Chen D , Lai H , Huang S 
Published: October 2006

This article presents a primitive-variable calculation procedure for a time-dependent deforming interface and its relevant conjugate viscous flows in a multi-fluid system. A deforming fluid/fluid interface boundary is explicitly tracked using a moving mesh. In order to decide the shape of the deforming interface separating two conjugate viscous flows on both sides, a ‘modified Ryskin-Leal method’ is proposed. This is combined with the ‘continuous stress method’ for interfacial velocity, previously developed by the authors, to treat the boundary conditions. The governing equations are solved by the SIMPLE method, which is implemented with high-order schemes to obtain high fidelity of interfacial transport and flow phenomena. The calculation procedure is verified. These include fluid droplets with documented numerical results and air bubbles with experimental data. Further verifications of the algorithm are carried out by numerically studying the dynamic behaviours of a rising air bubble; these dynamic behaviours include the time-dependent rising, deformation, evolution of flow fields, and propagation of concentration field.
Perilymphatic fistula: An unusual cause of meniere's syndrome in a prepubertal child
Authors: Arenberg I.Kaufman , May Mark , Stroud Malcolm H. 
Published: October 2006

AbstractNon‐traumatic, spontaneous perilymph fistula of the oval window is an unusual cause of Ménière's syndrome in a child. In this case, all of the audio‐vestibular criteria for a diagnosis of Ménière's syndrome (or clinical endolymphatic hydrops), including a temporary threshold shift after the glycerol test, were demonstrated. At exploratory tympanotomy, a perilymph fistula, demonstrated at the footplate margins was plugged with fat. There was significant immediate postoperative and six‐month follow‐up improvement in perception of pure tone, speech reception threshold (SRT) and discrimination score.
Depression of the evoked cortical potential by ethacrynic acid
Authors: Walloch Richard A. , Anthony Jonathan , Gibbons Nannette 
Published: October 2006

AbstractThe effect of a 45 mg/kg injection of Ethacrynic acid upon the threshold of the potential evoked from the guinea pig's auditory cortex was determined. Thirty minutes after the drug injection, the thresholds for the evoked potential at 0.5 and 1 kHz were depressed approximately 20 db, while the thresholds at 4 and 10 kHz were depressed approximately 40 db. Although not complete, substantial recovery of the evoked potential threshold was observed in all but one guinea pig two hours after the drug injection. The changes in the evoked potential threshold were the same order of magnitude as those previously reported for the cochlear microphonic and endolymphatic potential.
Evaluation and treatment of vocal cord paralysis
Authors: Maisel Robert H. , Ogura Joseph H. 
Published: October 2006

AbstractOne hundred eighty‐one patients with unilateral or bilateral vocal cord paralysis unrelated to laryngeal carcinoma or its therapy were studied. The orderly diagnostic profile used to delineate cause of the paralysis includes CBC, VDRL blood sugar profile, latex fixation and serum sampling for toxic heavy metals. The radiologic and endoscopic evaluation is done to completion unless contraindicated, to assess aspiration as well as to observe laryngopharyngeal structures which may cause the paralysis. This evaluative profile defined the etiology of cord paralysis in 80 percent of patients, despite exclusion of viral disease as a cause subsequent to upper respiratory infection. Blunt trauma and previous neck surgery each were responsible for 23 percent of the cases. Fifty‐four patients had bilateral paralysis of which 22 were post thyroidectomy. Surgical repair for cord paralysis was symptomatic, and included 28 successful teflon injected cords. Recurrent laryngeal nerve decompression was successful in four of five operations and arytenoidectomy was performed in 39 patients.
Diverting the paralyzed larynx: A reversible procedure for intractable aspiration.
Authors: Lindeman Roger C. 
Published: October 2006

AbstractSome unfortunate patients suffer disorders which in one way or another, usually neurologically, severely restrict the larynx in its role as a protector of the lower airway. Aspiration ensues, and unless it can be successfully managed, repeated episodes of a violent pneumonitis may lead to terminal chest problems.In some patients, even the cuffed tracheostomy tubes of new and improved design do not adequately prevent aspiration over an extended time interval, as evidenced by repeated bouts of aspiration pneumonia despite these cuffed tubes and despite optimal intensive care.For these patients with intractable aspiration, and in whom recovery is expected only after a prolonged period of time, we have suggested a diverting procedure which employs a tracheo‐esophageal anastomosis, as an effective yet reversible solution. Such an anastomosis with concomitant tracheostomy allows aspiration of saliva and even food to occur through the malfunctioning larynx but diverts it back into the esophagus through the tracheo‐esophageal anastomosis.In normal mongrel dogs we demonstrated that an end‐to‐side tracheoesophageal anastomosis is well tolerated and can be performed without damage to the intrinsic larynx or recurrent laryngeal nerves. The tracheoesophageal lumen remained patent and the anastomosis intact for as long as these animals were observed prior to reconstruction.The reversibility of the tracheo‐esophageal anastomosis was demonstrated in these dogs by excising the anastomosis, repairing the esophageal defect, and restoring the continuity of the trachea by end‐to‐end anastomosis. Vocal cord motion remained intact, the dogs ate normally, and barked once again.A tracheo‐esophageal anastomosis was performed in a 60‐year‐old white female who had suffered lower cranial nerve damage as a result of a large acoustic tumor and the excision thereof. Despite every effort to control aspiration, pneumonitis occurred and became fulminant.The diverting tracheo‐esophageal anastomosis was performed with relative ease and was well tolerated by the patient. Aspiration was totally and dependably controlled, and no further chest complications occurred. Her nasogastric feeding tube was removed, and she ate a regular diet with very little difficulty. She gained in strength, became much more alert mentally, and is now taking care of herself in a nursing home.We are following her progress by indirect laryngoscopy and barium swallow examinations and at five months post anastomosis, we are possibly seeing the first signs of lower cranial nerve recovery. We hope that reconstruction and restoration of function will soon be possible.We feel that the results to date of our animal experimentation and of our case report are satisfactory. Many questions remain unanswered, however, and for this reason we must emphasize a very conservative approach to the clinical application of this procedure.
Audiological evaluation following acupuncture for hearing loss
Authors: Davis James M. , Krapp Dwight E. , Wilder Martha L. , Lawrence Clifton F. 
Published: October 2006

AbstractSix patients, diagnosed as having bilateral, sensori‐neural hearing losses received audiological evaluations before and after acupuncture treatments. A comparison of mean pre‐ and post‐treatment pure tone air conduction and speech reception thresholds indicated no significant improvement with respect to auditory acuity. Although most threshold shifts were within a ±5 db clinical error envelope, there was a general tendency for poorer hearing levels.
Arterial blood gas changes following nasal packing in dogs
Authors: Cavo John W. , Kawamoto Satoru , Berlin Barry P. , Zollinger William , Ogura Joseph H. 
Published: October 2006

AbstractPrevious clinical studies pertaining to blood gas changes following nasal packing have agreed that the packing is frequently followed by hypoxia but have found differing responses in arterial PCO2 to nasal packing. This is of more than incidental importance, because the mechanisms by which hypoxia develops should determine the method by which the hypoxia is treated.The various causes of hypoxia are reviewed, and a method of instituting an indwelling systemic arterial catheter for the purpose of drawing sequential blood samples for gas determinations is described.Using the indwelling arterial catheters, arterial blood was sampled from a series of awake, unsedated dogs before, during, and after the dogs were subjected to anterior and posterior nasal packing. Blood gas determinations showed significant depressions of PO2 and elevations of PCO2 during the period when the packing was in place. The altered blood gas values quickly returned to essentially normal (control) values after the packing was removed.In order to help assess the degree of lower airway response to an upper airway stimulus as a cause of these blood gas changes, the protocol was repeated in previously laryngectomized dogs. In these animals no consistently significant change occurred in either the PO2 or PCO2 following either the packing or its removal. Our findings suggest that airway obstruction (and hypoventilation) rather than increased bronchomotor tone is the main cause of hypoxia in awake dogs with anterior and posterior packing. Because of the likelihood of hypoventilation and significant hypercarbia in patients in whom nasal packing is employed, we discourage the routine usage of oxygen, unless blood gas levels are checked prior to the institution of oxygen therapy.
Laryngopharyngeal injuries
Authors: Krekorian Edmund A. 
Published: October 2006

AbstractThe patient who sustains trauma to the neck may present with symptoms strongly suggesting an acute injury to the larynx. The laryngeal injury may be real or imagined; however, the clinical manifestations may be so overwhelmingly indicative of a laryngeal injury that a small tear in the adjacent upper gut may be overlooked. Failure to diagnose an upper gut injury can result in a confusing parade of symptoms and signs, great morbidity and even death.Two cases are presented, each illustrating certain unique aspects of upper gut and laryngeal injuries. The history, diagnosis, operative management and clinical course of each patient are described. Attention is given to the unique facets of each case which make upper gut injury a fascinating and challenging surgical entity. Each case is discussed in terms of diagnostic and management errors or areas of controversy. Finally, certain general concepts of management of upper gut injuries are described.
Thin section computed tomography of the temporal bone
Authors: Shaffer Katherine A. , Haughton Victor M. 
Published: October 2006

AbstractThe applications of computed tomography (CT) in temporal bone studies have increased because of thin sections (< 2 mm), high spatial resolution (< 0.8 mm) and high resolution reconstruction algorithms. Thin section CT was performed in 56 patients suspected of having acoustic neuromas, other tumors, cholesteatomas or fractures. High resolution experimental image reconstruction was performed in some cases. In most cases, the pathologic process was demonstrated as well or better on CT scans than on complex motion tomograms. We concluded that high resolution, thin section CT is the technique of choice to evaluate patients with temporal bone tumors. CT is an effective means of studying patients with large cholesteatomas and fractures, although conventional tomography may be complementary in some cases. The value of CT in patients with otosclerosis and inflammatory disease of the middle ear should be evaluated more extensively.