bluuebunny/crossref_metadata_2025 huggingface dataset:
Involvement of T‐type calcium channels in excitatory junction potentials in rat resistance mesenteric arteries
Authors: Xi Qi , Ziogas James , Roberts Jonathan A , Evans Richard J , Angus James A
Published: November 2002

We investigated the role of voltage‐operated calcium channels in sympathetic transmission and depolarization‐induced contractions in the rat mesenteric artery. In particular, we investigated the role of the T‐type voltage‐operated calcium channels (T‐channels) in mediating excitatory junction potentials (EJPs).

EJPs were evoked by electrical field stimulation (trains of five stimuli at 0.9 Hz) in small mesenteric arteries. The average resting membrane potential was −59.8±0.5 mV (n=65). Trains of stimuli evoked individual EJPs with the peak EJP of 6±0.2 mV (n=34) occurring with the second stimulus. Trains of EJPs were inhibited 90% by tetrodotoxin (0.1 μM) or by ω‐conotoxin GVIA (GVIA, 10 nM) indicating their neural origin.

The EJPs were not inhibited by the L‐type calcium channel blocker nicardipine at 0.1 μM, a concentration sufficient to abolish the contraction to potassium depolarization. However, mibefradil (3 μM), considered a relatively selective T‐channel antagonist, inhibited the EJPs by about 50%. This concentration of mibefradil did not inhibit GVIA‐sensitive electrically‐evoked twitches of the rat vas deferens. Thus the action of mibefradil in reducing EJPs is unlikely to be due to either inhibition of L‐ or N‐type channels but is probably due to inhibition of T‐channels.

The finding that Ni2+ (300 μM), an inhibitor of T‐type calcium channels, also reduced EJP amplitude by about 80% but did not block electrically‐evoked twitches in the rat vas deferens, further supports an important role of T‐channels in mediating small depolarizations associated with the EJPs evoked by sympathetic nerve stimulation.

British Journal of Pharmacology (2002) 137, 805–812. doi:10.1038/sj.bjp.0704943
Impact of ageing on the antinociceptive effect of reference analgesics in the Lou/c rat
Authors: Jourdan Didier , Pickering Gisèle , Marchand Fabien , Gaulier Jean‐Michel , Alliot Josette , Eschalier Alain
Published: November 2002

Research on the evolution of experimental pain perception and on the achievement of analgesia with ageing has led so far to contradictory results.

This study investigated in the rat the impact of ageing on the antinociceptive effect of reference analgesics, acetaminophen (50, 100, 200, 400 mg kg−1 po), aspirin (50, 100, 200, 400 mg kg−1 sc), clomipramine (5, 10, 20, 40 mg kg−1 sc) and morphine (1.25, 2.5, 5, 10 mg kg−1 sc).

Lou/c rats were chosen because they provide a model of healthy ageing and they do not develop obesity with age. Three groups of 40 rats each (mature (4 months), middle‐aged (18 months) and old (26 months)), were treated with each drug at 14 days interval. Two tests were used: a thermal test (tail immersion in 48°C water and measurement of reaction latency) and a mechanical test (paw pressure and measurement of struggle threshold).

Results confirm the increased mechanical sensitivity to pain and no change in thermal sensitivity for old rats compared to mature and middle‐aged animals. They show a marked decrease in the effect of morphine with age and no age‐related effect for acetaminophen, aspirin or clomipramine. Plasma levels of morphine and metabolites are not different in the three age groups.

It is likely that the influence of age on morphine analgesia is linked mainly to pharmacodynamic rather than pharmacokinetic changes.

British Journal of Pharmacology (2002) 137, 813–820. doi:10.1038/sj.bjp.0704944
Effects of pharmacological preconditioning with U50488H on calcium homeostasis in rat ventricular myocytes subjected to metabolic inhibition and anoxia
Authors: Ho J C S , Wu S , Kam K W L , Sham J S K , Wong T M
Published: November 2002

The effects of pharmacological preconditioning with U50488H (U50), a selective κ‐opioid receptor agonist, on Ca2+ homeostasis in rat ventricular myocytes subjected for 9 min to metabolic inhibition (MI) and anoxia (A), consequences of ischaemia, were studied and compared with those of preconditioning with brief periods of MI/A.

Precondition with 30 μM of U50 for three cycles of 1 min each cycle separated by 3 min of recovery (UP) significantly increased the percentage of non‐blue cells following MI/A. The effect of UP is the same as that of preconditioning with an inhibitor of glycolysis and an oxygen scavenger for three 1‐min cycles separated by three‐minute recovery (MI/AP). The results indicate that like MI/AP, UP also confers cardioprotection.

MI/A increased intracellular Ca2+ ([Ca2+]i) and reduced the amplitude of caffeine‐induced [Ca2+]i transients, an indication of Ca2+ content in the sarcoplasmic reticulum (SR). MI/A also reduced the electrically‐induced [Ca2+]i transient, that indicates Ca2+‐release during excitation‐contraction coupling, and Ca2+ sparks in unstimulated myocytes, that indicates spontaneous Ca2+‐release from SR. It also prolonged the decline of the electrically‐induced [Ca2+]i transient and slowed down the recovery of the electrically‐induced [Ca2+]i transient after administration of caffeine. In addition, MI/A prolonged the decline of caffeine induced [Ca2+]i transient, an indication of Na+–Ca2+ exchange activity, and UP prevented it. So UP, that confers cardioprotection, prevented the changes induced by MI/A. With the exception of Ca2+‐spark, which was not studied, the effects of MI/AP are the same as those of UP.

It is concluded that pharmacological preconditioning with U50, that confers immediate cardioprotection, prevents changes of Ca2+ homeostasis altered by MI/A in the rat heart. This may be responsible, at least partly, for the cardioprotective action.

The study also provided evidence that MI/A causes mobilization of Ca2+ from SR to cytoplasm causing Ca2+‐overload which may be due to reduced Ca2+‐uptake by SR. MI/A also reduces spontaneous and electrically induced Ca2+ release from SR.

British Journal of Pharmacology (2002) 137, 739–748. doi:10.1038/sj.bjp.0704945
Possible role of histamine (H1‐ and H2‐) receptors in the regulation of meningeal blood flow
Authors: Dux Mária , Schwenger Nina , Messlinger Karl
Published: November 2002

Vasodilatation in the dura mater has been suggested to play an important role in the pathophysiology of vascular headaches. Histamine may contribute to these vascular changes. The aim of the present study was to examine the role of different histamine receptors in histamine‐induced meningeal hyperperfusion using laser Doppler flowmetry.

The blood flow in the medial meningeal artery was monitored in the exposed parietal dura mater encephali of barbiturate anaesthetized rats. Local application of histamine (10−5 and 10−4 M) onto the dura caused increases in flow to 114.2±9.6 and 135.1±19.1%, respectively, of the basal flow.

Flow increases induced by topical application of histamine (10−4 M) were reduced by local pretreatment with the H2‐receptor antagonist cimetidine (0.4 and 4 mM) to 63.4±17 and 37.8±18.8%, respectively. Systemic pre‐administration of cimetidine (5 mg kg−1 i.v.) did not change histamine‐induced flow increases.

Local pretreatment with the H1‐receptor antagonist cetirizine (2 μM) further increased the flow evoked by topical histamine administration (10−4 M) to 123.5±14.7% of the histamine control.

Increases in blood flow induced by i.v. administration of histamine (10 μg kg−1) were reduced by i.v. pre‐injection of cetirizine (50 μg kg−1) to 31.9±9% but not by i.v. cimetidine (5 mg kg−1).

We conclude that histamine‐induced relaxation of dural arterial vessels is mediated by H2‐receptors, most likely located on vascular smooth muscle cells, and by endothelial H1‐receptors. In addition, H1‐receptors on smooth muscle cells may mediate vasoconstriction.

British Journal of Pharmacology (2002) 137, 874–880. doi:10.1038/sj.bjp.0704946
Nitric oxide inhibits capacitative Ca2+ entry by suppression of mitochondrial Ca2+ handling
Authors: Thyagarajan Baskaran , Malli Roland , Schmidt Kurt , Graier Wolfgang F , Groschner Klaus
Published: November 2002

Nitric oxide (NO) is a key modulator of cellular Ca2+ signalling and a determinant of mitochondrial function. Here, we demonstrate that NO governs capacitative Ca2+ entry (CCE) into HEK293 cells by impairment of mitochondrial Ca2+ handling.

Authentic NO as well as the NO donors 1‐[2‐(carboxylato)pyrrolidin‐1‐yl]diazem‐1‐ium‐1,2‐diolate (ProliNO) and 2‐(N,N‐diethylamino)‐diazenolate‐2‐oxide (DEANO) suppressed CCE activated by thapsigargin (TG)‐induced store depletion. Threshold concentrations for inhibition of CCE by ProliNO and DEANO were 0.3 and 1 μM, respectively.

NO‐induced inhibition of CCE was not mimicked by peroxynitrite (100 μM), the peroxynitrite donor 3‐morpholino‐sydnonimine (SIN‐1, 100 μM) or 8‐bromoguanosine 3′,5′‐cyclic monophosphate (8‐BrcGMP, 1 mM). In addition, the guanylyl cyclase inhibitor 1H‐[1,2,4] oxadiazole[4,3‐a] quinoxalin‐1‐one (ODQ, 30 μM) failed to antagonize the inhibitory action of NO on CCE.

DEANO (1–10 μM) suppressed mitochondrial respiration as evident from inhibition of cellular oxygen consumption. Experiments using fluorescent dyes to monitor mitochondrial membrane potential and mitochondrial Ca2+ levels, respectively, indicated that DEANO (10 μM) depolarized mitochondria and suppressed mitochondrial Ca2+ sequestration. The inhibitory effect of DEANO on Ca2+ uptake into mitochondria was confirmed by recording mitochondrial Ca2+ during agonist stimulation in HEK293 cells expressing ratiometric‐pericam in mitochondria.

DEANO (10 μM) failed to inhibit Ba2+ entry into TG‐stimulated cells when extracellular Ca2+ was buffered below 1 μM, while clear inhibition of Ba2+ entry into store depleted cells was observed when extracellular Ca2+ levels were above 10 μM. Moreover, buffering of intracellular Ca2+ by use of N,N′‐[1,2‐ethanediylbis(oxy‐2,1‐phenylene)] bis [N‐[25‐[(acetyloxy) methoxy]‐2‐oxoethyl]]‐, bis[(acetyloxy)methyl] ester (BAPTA/AM) eliminated inhibition of CCE by NO, indicating that the observed inhibitory effects are based on an intracellular, Ca2+ dependent‐regulatory process.

Our data demonstrate that NO effectively inhibits CCE cells by cGMP‐independent suppression of mitochondrial function. We suggest disruption of local Ca2+ handling by mitochondria as a key mechanism of NO induced suppression of CCE.

British Journal of Pharmacology (2002) 137, 821–830. doi:10.1038/sj.bjp.0704949
Anandamide induces cough in conscious guinea‐pigs through VR1 receptors
Authors: Jia Yanlin , McLeod Robbie L , Wang Xin , Parra Leonard E , Egan Robert W , Hey John A
Published: November 2002

Endogenous neuronal lipid mediator anandamide, which can be synthesized in the lung, is a ligand of both cannabinoid (CB) and vanilloid receptors (VR). The tussigenic effect of anandamide has not been studied. The current study was designed to test the direct tussigenic effect of anandamide in conscious guinea‐pigs, and its effect on VR1 receptor function in isolated primary guinea‐pig nodose ganglia neurons.

Anandamide (0.3–3 mg·ml−1), when given by aerosol, induced cough in conscious guinea‐pigs in a concentration dependent manner. When guinea‐pigs were pretreated with capsazepine, a VR1 antagonist, the anandamide‐induced cough was significantly inhibited. Pretreatment with CB1 (SR 141716A) and CB2 (SR 144528) antagonists had no effect on anandamide‐induced cough. These results indicate that anandamide‐induced cough is mediated through the activation of VR1 receptors.

Anandamide (10–100 μM) increased intracellular Ca2+ concentration estimated by Fluo‐4 fluorescence change in isolated guinea‐pig nodose ganglia cells. The anandamide‐induced Ca2+ response was inhibited by two different VR1 antagonists: capsazepine (1 μM) and iodo‐resiniferatoxin (I‐RTX, 0.1 μM), indicating that anandamide‐induced Ca2+ response was through VR1 channel activation. In contrast, the CB1 (SR 141716A, 1 μM) and CB2 (SR 144528, 0.1 μM) receptor antagonists had no effect on Ca2+ response to anandamide.

In conclusion, these results provide evidence that anandamide activates native vanilloid receptors in isolated guinea‐pig nodose ganglia cells and induces cough through activation of VR1 receptors.

British Journal of Pharmacology (2002) 137, 831–836. doi:10.1038/sj.bjp.0704950
Evaluation of the Bone Injection Gun as a Method for Intraosseous Cannula Placement for Fluid Therapy in Adult Dogs
Authors: Olsen Dennis , Packer Brett E. , Perrett Jamis , Balentine Heather , Andrews Gordon A.
Published: November 2002

Objective— To evaluate the Bone Injection Gun (BIG) for placement of intraosseous cannulas through impact penetration and compare it with a standard Jamshidi bone marrow needle (JBMN) and to compare fluid delivery dynamics through each device.

Study Design— Randomized in vivo study.

Animals— Forty‐eight mature dogs.

Methods— During surgical laboratories, dogs were randomly assigned to 2 groups (n = 24), and intraosseous access in the proximal tibial metaphysis was obtained using a BIG or JBMN. Variables measured during placement included insertion success, time required for placement, and alterations in respiratory rate (RR), heart rate (HR), and systolic blood pressure. After placement, maintenance fluids were administered to 6 dogs from each group, and fluids were administered under pressure to 6 dogs from each group to compare rates of delivery through each device. After euthanasia, the tibiae were harvested to evaluate and compare the morphologic consequences of needle and cannula placement.

Results— Successful placement occurred in 20 (83%) dogs for the BIG and 23 (96%) dogs for the JBMN, which was not significantly different (P= .3475). Time required for placement was significantly less (P= .0024) for the BIG (mean, 22.4 ± 8.2 seconds) compared with the JBMN (mean, 42.0 ± 28.1 seconds). Significant increases in RR occurred in both groups and in the HR for the BIG group, but significant differences were not noted between groups. Mean rate of pressurized fluid administration was similar for both groups. Two distinct patterns of cortical bone damage occurred, but the clinical significance of this observation is uncertain.

Conclusions— The BIG provides more rapid access to the intraosseous space for fluid administration than the JBMN.

Clinical Relevance— The BIG is an effective alternative for obtaining rapid access to the intraosseous space for emergency fluid and drug administration.
The Effect of Cranial Cruciate Ligament Insufficiency on Caudal Cruciate Ligament Morphology: An Experimental Study in Dogs
Authors: Zachos Terri A. , Arnoczky Steven P. , Lavagnino Michael , Tashman Scott
Published: November 2002

Objectives—To investigate the effect of cranial cruciate ligament (CrCL) insufficiency on morphology of the canine caudal cruciate ligament (CdCL).

Study Design—In vivo experimental study.

Animals—Five adult foxhounds.

Methods—Two years after CrCL transection, the histologic appearance of CdCLs from CrCL‐deficient and unoperated contralateral control (CrCL‐intact) stifle joints were evaluated using light and transmission electron microscopy.

Results—CdCLs from CrCL‐deficient joints had extracellular matrix changes, characterized by chondroid metaplasia and disruption of cell architecture. Percent of small‐diameter fibrils in CdCLs from CrCL‐deficient joints was significantly greater (P<.05) than that in CdCLs from CrCL‐intact joints. Collagen fibril density in CdCLs from CrCL‐deficient joints (41.09 ± 5.39%) tended to be less than that in CdCLs from CrCL‐intact joints (52.96 ± 6.92%); however, this difference was not significant (P= .056). Mean eccentricity (ratio of minor to major diameters) of collagen fibrils was significantly (P< .0001) lower for CdCLs from CrCL‐deficient joints (0.85 ± 0.016) when compared with that for CdCLs from CrCL‐intact joints (0.87 ± 0.015).

Conclusions—Significant alterations were found in the morphology of CdCLs from CrCL‐deficient joints. These changes may be associated with repetitive microtrauma to the CdCL secondary to instability or enzymatic degradation in the hostile synovial environment of an unstable joint.

Clinical Relevance—Regardless of the cause, the switch to a predominantly small‐diameter collagen fibril profile may reflect compromised material properties of the CdCL. This should be taken into account when considering surgical techniques that rely on the CdCL to stabilize CrCL‐deficient stifles.
Epidemiologic Evaluation of Postoperative Wound Infection in Clean‐Contaminated Wounds: A Retrospective Study of 239 Dogs and Cats
Authors: Nicholson Matthew , Beal Matthew , Shofer Frances , Brown Dorothy Cimino
Published: November 2002

Objective—To evaluate risk factors for development of postoperative wound infections in clean‐contaminated wounds.

Study Design—Retrospective clinical study.

Sample Population—Two hundred thirty‐nine dogs and cats that had clean‐contaminated surgical procedures.

Methods—Records of animals that had a clean‐contaminated surgical procedure and were prospectively monitored for development of postoperative wound infection were reviewed. Prospective data included signalment, nutritional status, body weight, duration of surgery, surgical procedures, wound classification, surgical site clip time before surgery, hypotension during surgery, the presence of an active distant infection, endocrinopathy, administration of an immunosuppressive agent, administration of antibiotics, and the type of antibiotic used. Additional retrieved data included total anesthesia time, temperature variables, blood loss, and suture material used.

Results—Intact males (P= .008) and animals with concurrent endocrinopathy (P= .008) were at a higher risk of development of postoperative wound infection. Total surgery time (P= .02) and total anesthesia time (P= .04) were longer in animals that developed postoperative wound infection. No other factors were statistically significant.

Conclusions—Intact males and animals with a concurrent endocrinopathy were at higher risk of postoperative wound infection after clean‐contaminated surgical procedures.

Clinical Relevance—Time under anesthesia and duration of surgery should be minimized to reduce the risk of wound infection in clean‐contaminated surgical procedures.
Survival and Prognostic Indicators for Dogs With Intrahepatic Portosystemic Shunts: 32 Cases (1990–2000)
Authors: Papazoglou Lysimachos G. , Monnet Eric , Seim Howard B.
Published: November 2002

Objective—To determine prognostic indicators for short‐term outcome and long‐term survival for dogs with intrahepatic portosystemic shunts (IPSS).

Study Design—Retrospective study.

Animals—Thirty‐two dogs of various breeds.

Methods—Clinical data extracted from medical records of dogs with IPSS were reviewed and included gender, age at surgery, weight, preoperative packed cell volume (PCV), total plasma protein concentration (TP), albumin (ALB), serum activities of alanine aminotransferase (ALT) and alkaline phosphatase (ALP), preprandial and postprandial bile acid concentrations (pre‐BA, post‐BA), blood urea nitrogen (BUN), glucose concentration, band neutrophils, per‐rectal nuclear scintigraphy shunt fraction, whether an angiogram was performed, shunt location at surgery, whether a partial or complete attenuation of the shunt was performed, rectal temperature at the end of surgery, and duration of surgical procedure. Follow‐up was determined from visits to the veterinary teaching hospital or by telephone communications with the owner or referring veterinarian.

Results—Median survival time was 35.68 months, and 1‐ and 2‐year probabilities of survival were 60% and 55%, respectively. Body weight, TP, ALB, and BUN were identified as prognostic indicators for short‐term outcome. PCV and TP were identified as prognostic indicators for long‐term survival.

Conclusions—PCV and TP were identified as prognostic indicators for long‐term survival, whereas body weight, TP, ALB, and BUN were identified as indicators for short‐term outcome in dogs with IPSS. Shunt location at surgery did not have any effect on short‐term outcome and long‐term survival.

Clinical Relevance—Total protein, ALB, BUN, and PCV can be used to determine prognosis of dogs with intrahepatic shunt.
Comparison of Double Dynamic Compression Plating Versus Two Configurations of an Internal Veterinary Fixation Device: Results of In Vitro Mechanical Testing Using a Bone Substitute
Authors: Haerdi‐Landerer Christina , Steiner Adrian , Linke Berend , Wahl Dieter , Schneider Erich , Hehli Markus , Frei Reto , Auer Jörg A.
Published: November 2002

Objective—To compare the mechanical properties of 2 configurations of a veterinary fixation system (VFS) for large animal long bones with dynamic compression plating (DCP).

Sample Population—Eighteen pairs of Canevasit tubes (Canevasit; Amsler und Frei, Schinznach Dorf, Switzerland) (length, 170 mm; diameter, 47.5 mm; cortex thickness, 10 mm), aligned with a 10‐mm gap, and stabilized with 2 DCP or 2 VFS implants.

Methods—Three groups (n = 6) were compared. Group 1 Canevasit tubes were stabilized with two 10‐hole, broad 4.5‐mm stainless steel DCP applied with both plates centered over the gap, in orthogonal planes parallel to the long axis of the tubes and staggered to allow bicortical fixation with ten 4.5‐mm, 52‐mm‐long cortex screws each. Group 2 tubes were stabilized similarly with 2 VFS implants, each composed of a stainless steel rod (length, 167 mm; diameter, 8 mm), and 10 clamps were applied in alternating fashion left and right on the rod and fixed bicortically with ten 4.5‐mm, 52‐mm‐long, cortex screws. Group 3 tubes were stabilized similarly, but using only 6 clamps/rod. All groups were tested initially in torsion within elastic limits and subsequently in 4‐point bending, with 1 implant on the tension side, until gap closure occurred.

Results—None of the constructs failed, but all had plastic deformation after 4‐point bending. No statistically significant differences were found among the 3 groups in torsional stiffness. Double DCP fixation was significantly stiffer and stronger in 4‐point bending, compared with both configurations of double VFS fixation.

Conclusions—The plate design was favored in this study. The VFS system may have to be adapted before further tests are conducted. Test modalities have to be chosen closer to clinical conditions (real bone, cyclic loading, closed gap).

Clinical Relevance—The veterinary fixation system has not yet proven its advantages for large animal long bone fracture repair. From the pure mechanical point of view, double DCP is the favored method for the treatment mentioned.
The Effect of a Porcine‐Derived Small Intestinal Submucosa Product on Wounds With Exposed Bone in Dogs
Authors: Winkler James T. , Swaim Steven F. , Sartin Eva A. , Henderson Ralph A. , Welch Janet A.
Published: November 2002

Objective—To determine the effect of a porcine‐derived small intestinal submucosa product (PSIS) on healing time, epithelialization, angiogenesis, contraction, and inflammation of wounds with exposed bone on the distal aspect of the limbs of dogs.

Study Design—Prospective, controlled, experimental study.

Animal Population—10 young adult, purpose‐bred, male Beagles.

Methods—Small wounds with exposed bone were created on the lateral aspect of metatarsal V and the medial aspect of metatarsal II on both hindlimbs. Three sheets of PSIS were sutured into the wounds of the treated limb, and the other limb served as a control. On day 10, punch biopsies of the medial metatarsal wounds were collected and were evaluated microscopically after routine hematoxylin and eosin and phosphotungstic acid hematoxylin (PTAH) staining. The lateral metatarsal wounds were evaluated by planimetry and laser Doppler perfusion imaging on days 7, 14, and 21. Time until complete wound healing was also recorded. The level of significance was set atP≤ .05for all statistical analyses.

Results—Laser Doppler perfusion measurements were significantly higher in control wounds on day 7, but no differences were noted on days 14 and 21. No significant differences in planimetric values, histopathologic appearance, or time until complete wound healing were noted among treated and control groups.

Conclusions—No objective differences in healing were noted between control wounds and wounds treated with PSIS.

Clinical Relevance—There appears to be no contraindication to the use of PSIS on clean wounds with exposed bone on the distal limbs of dogs. However, our objective data provides no evidence that this product affects epithelialization, contraction, or time to complete healing in wounds with exposed bone.
Effects of Suture Tension and Surgical Approach During Unilateral Arytenoid Lateralization on the Rima Glottidis in the Canine Larynx
Authors: Bureau Stephane , Monnet Eric
Published: November 2002

Objectives— To evaluate the effect of abduction suture tension and cricothyroid (CT) joint disarticulation on the area, height, and width of the rima glottidis (RG) during unilateral arytenoid lateralization.

Study Design— Experimental study.

Animals— Nine canine cadaver larynges.

Methods— Left arytenoid lateralization was performed with high or low abduction suture tension. RG area, height, and width were measured by computerized planimetric analysis with the epiglottis in an open and closed position. The experiment was performed with the CT joint intact and disarticulated. The effects of suture tension, CT disarticulation, and their interaction on RG area with the epiglottis closed or open were evaluated by repeated measures analysis of variance (ANOVA).

Results— RG area increased by 82% and 129% (P < .0001) with low and high suture tension, respectively. The aperture not covered by the epiglottis in a closed position was 467% larger with high suture tension than with low tension (P < .0001). CT disarticulation had no significant effect on RG geometry with either low or high suture tension (P= .4970).

Conclusions— Low suture tension increased RG area when the epiglottis was in an open position without increasing RG aperture when the epiglottis was closed. Suture tension had a significant effect on RG opening when the epiglottis was closed. CT disarticulation did not modify the geometry of the RG.

Clinical Relevance— Use of a low‐suture tension should be considered during arytenoid lateralization because it has the potential to reduce the risk of aspiration pneumonia.
Influence of Bolt Tightening Torque, Wire Size, and Component Reuse on Wire Fixation in Circular External Fixation
Authors: Wosar Marc A. , Marcellin‐Little Denis J. , Roe Simon C.
Published: November 2002

Objectives—To evaluate the effects of bolt torque, wire size, and component reuse on the ability to maintain wire tension in 3 external skeletal fixation systems.

Study—Design Biomechanical study.

Methods—Yield strength in tension of 1.0‐, 1.2‐, 1.5‐, and 1.6‐mm‐diameter wires, and yield strength in torque of Hofmann Small Bone Fixation (SBF) cannulated and slotted bolts and IMEX regular and miniature bolts were determined on a testing machine. The minimum bolt tightening torque needed to prevent wire slippage at clinically recommended wire tensions was determined. Components were tested 10 times, and loads at slippage were recorded.

Results—The IMEX system required a mean of 8 Nm of bolt tightening torque to maintain 900 N (1.6‐mm wires). The SBF system required a mean of 3 Nm bolt torque to maintain 300 N (1.0‐mm wires) and 5 Nm to maintain 600 N (1.2‐mm wires). The SBF cannulated bolt required 9 Nm of torque to maintain 900 N (1.5‐mm wires). The SBF slotted bolts could only maintain 800 N before yield. The IMEX miniature system required a mean bolt torque of 1.1 Nm to maintain 300 N. The cannulated and slotted bolts from both manufacturers failed to maintain 70% of initial wire tension after 7 and 4 uses, respectively.

Conclusions—The IMEX systems and the SBF system using 1.0‐ and 1.2‐mm wires could maintain clinically recommended wire tension safely. Only the IMEX system could maintain clinically recommended wire tension safely using 1.5‐ or 1.6‐mm wires.

Clinical Relevance—The SBF system using 1.0‐ and 1.2‐mm wires and the IMEX system using all wire sizes can maintain clinically relevant wire tension. The SBF system using 1.5‐mm wires could not. Cannulated and slotted bolts should not be used more than 6 and 3 times, respectively. Nuts should not be reused.
Pasteurized Tumoral Autograft as a Novel Procedure for Limb Sparing in the Dog: A Clinical Report
Authors: Buracco Paolo , Morello Emanuela , Martano Marina , Vasconi Maria Elisabetta
Published: November 2002

Objective—To evaluate use of a pasteurized tumoral autograft prepared from the resected primary bone neoplasm for limb sparing in a dog with distal radial osteosarcoma (OSA).

Study Design—Clinical case report.

Animals—A 9‐year‐old male Maremma shepherd dog.

Methods—After right distal radial OSA removal, the tumoral autograft was pasteurized. The excised bone segment was placed in a sterile watertight box containing sterile saline solution preheated to 65°C in a water bath. The box was kept immersed in the water bath at 65°C for 40 minutes to kill the tumor cells. The autograft was then fixed in the host with a plate and screws based on standard AO/ASIF technique for carpal arthrodesis. Three doses of cisplatin (70 mg/m2intravenously) were administered, 3 weeks apart; the initial dose was administered the day after surgery.

Results—The autograft was incorporated in a manner comparable to an allograft, and after 708 days, the metallic implants were removed. A 1‐month activity restriction as well as spoon splint to protect the leg from a full loading were used thereafter. Limb function was fair to good, and the dog remains disease free after 56 months.

Conclusions—A pasteurized autograft consisting of the resected primary bone neoplasm is a valid alternative to a cortical bone allograft for limb sparing in dogs with appendicular OSA in terms of feasibility and pattern of healing.

Clinical Relevance—This procedure can be an alternative method of limb sparing when difficulties are encountered in establishing and maintaining a canine bone allograft bank.
Dorsal Displacement of the Soft Palate in 92 Horses During High‐Speed Treadmill Examination (1993–1998)
Authors: Parente Eric J. , Martin Benson B. , Tulleners Eric P. , Ross Michael W.
Published: November 2002

Objective—To evaluate the occurrence of dorsal displacement of the soft palate (DDSP) during high‐speed treadmill (HSTM) exercise in racehorses, and determine treatment efficacy relative to the endoscopic findings observed during resting and HSTM endoscopic examination.

Study Design—Retrospective study.

Animals—Ninety‐two racehorses (74 Thoroughbreds, 18 Standardbreds).

Methods—The signalment, history (clinical and race), treatments, and video recordings made during resting and HSTM endoscopy were reviewed in 92 racehorses that developed DDSP during HSTM exercise. Only horses that completed 3 starts before and after HSTM examination were included in performance‐outcome analysis. Statistical associations were made between the independent variables (the historical findings and the resting and HSTM endoscopic findings) and performance outcome.

Results—Forty‐five horses (49%) displaced their palate in an uncomplicated manner, whereas the other horses either had another upper‐respiratory abnormality in association with DDSP (35) or displaced after swallowing (12). Although respiratory noise was not recorded during HSTM exercise, only 57 horses (62%) that developed DDSP during HSTM examination had a history of abnormal upper‐respiratory noise. For the 45 horses that met the criteria for performance outcome analysis, there were no independent variables recorded during resting or HSTM endoscopy that had a significant association with performance outcome. Treatment for DDSP varied by clinician. Overall, 29 horses (64%) had improved average earnings per start after diagnosis and treatment.

Conclusions—Thirty‐five horses (38%) that had DDSP during HSTM endoscopy had no previous history of abnormal upper‐respiratory noise, and 74 (80%) had no structural abnormalities noted on resting endoscopic examination.

Clinical Relevance—HSTM examination is an excellent tool for diagnosis of DDSP and the manner in which it occurs. DDSP did not occur similarly in all horses, and was often associated with another upper‐respiratory abnormality. Thus, it is unlikely that a single treatment can be applied effectively for all horses that experience DDSP. Both surgical and medical treatments can be beneficial in improving a horse's performance after a diagnosis of DDSP is made. Neither resting nor HSTM endoscopic findings were clearly prognostic.
Malignant Transformation of an Aneurysmal Bone Cyst in a Dog
Authors: Barnhart Matthew D.
Published: November 2002

Objective—To report malignant transformation of an aneurysmal bone cyst in a dog.

Study Design—Case report.

Sample Population—Client‐owned dog.

Results—A 5‐year‐old male Labrador retriever was diagnosed with an aneurysmal bone cyst of the distal aspect of the right ulna. Surgical curettage resulted in remission of clinical signs for 33 months. Because of recurrence of clinical signs, a distal ulnar ostectomy was performed. Histopathologic examination of the excised specimen revealed a moderately differentiated chondrosarcoma at the level of the bone cyst. Limb function was normal for 17 months until a subcutaneous mass, determined to be a chondrosarcoma, occurred at the level of the shoulder. A right forequarter amputation was performed.

Conclusions—Aneurysmal bone cysts are benign but may be transformed into a malignancy after surgical manipulation. Complete surgical excision should be attempted where possible. In this case, distal ulnar ostectomy was an effective means of preserving limb function and preventing local recurrence of chondrosarcoma.
Prognostic Indicators for Time to Ambulation After Surgical Decompression in Nonambulatory Dogs With Acute Thoracolumbar Disk Extrusions: 112 Cases
Authors: Davis Garrett J. , Brown Dorothy C.
Published: November 2002

Objectives—To determine prognostic indicators for time to ambulation after surgical decompression in nonambulatory dogs with intact pain sensation and acute Hansen type‐1 disk extrusions.

Study Design—Retrospective clinical study.

Animals—One‐hundred twelve dogs with Hansen type‐I disk extrusions that had decompressive hemilaminectomy or dorsal laminectomy.

Methods—All dogs had thoracolumbar disk extrusion and were nonambulatory with intact pain sensation at admission. Variables considered included age, weight, voluntary motor function at time of anesthetic induction, glucocorticoid use, times from onset of nonambulatory status to admission and surgical decompression, time in hospital to surgical decompression, anesthetic time, surgical time, number of contrast injections required to perform a diagnostic myelogram, postoperative pain sensation, and postoperative voluntary motor function. Time to ambulation was defined as the number of days from surgical decompression until the dog was able to stand and take a series of steps without assistance.

Results—One‐hundred seven dogs (96%) were able to ambulate within 3 months. The mean time to ambulation was 12.9 days and was significantly shorter if dogs had postoperative voluntary motor function (7.9 daysv16.4 days,P< .0001). No other variable had a significant association with time to ambulation.

Conclusions—Few perioperative variables have prognostic value for return to ambulation. Nonambulatory dogs with intact pain sensation and Hansen type‐1 disk extrusions in the thoracolumbar spine that are treated with surgical decompression have a favorable prognosis.

Clinical Relevance—The presence of postoperative voluntary motor function is a favorable prognostic indicator for early return to ambulation.
Optimization of sensitivity and noise in piezoresistive cantilevers
Authors: Yu Xiaomei , Thaysen J. , Hansen O. , Boisen A.
Published: November 2002

In this article, the sensitivity and the noise of piezoresistive cantilevers were systematically investigated with respect to the piezoresistor geometry, the piezoresistive materials, the doping dose, the annealing temperature, and the operating biased voltage. With the noise optimization results, dimension optimized array cantilevers were designed and fabricated by using single-crystal silicon, low-pressure chemical-vapor deposition (LPCVD) amorphous silicon and microcrystalline silicon as piezoresistive layers. Measurement results have shown that the smallest Hooge factor (α) was 3.2×10−6, the biggest gauge factors was 95, and the minimum detectable deflection (MDD) at 6 V and 200 Hz-measurement bandwidth was 0.3 nm for a single-crystal silicon cantilever. Of the two LPCVD silicon piezoresistive cantilevers, amorphous silicon piezoresistors had relatively lower 1/f noise. The MDD for a LPCVD silicon cantilever at a 200 Hz-measurement bandwidth was 0.4 nm. For all kinds of piezoresistive cantilevers, the 1/f noises were decreased by 35%–50% and the gauge factors were decreased by 60–70% if the doping dose were increased by ten times. The annealing at 1050 °C for 30 min decreased 1/f noise by about 65% compared with the 950 °C for 10 min treatments. The cantilevers with a relatively higher-doping dose gave smaller MDD even though the gauge factors of them were decreased by nearly a factor of 1.8. The higher-biased voltages had no great improvements on the MDD due to the 1/f noise dominance.
Time dependence of tunnel statistics and the energy resolution of superconducting tunnel junctions
Authors: Verhoeve P. , Hartog R. den , Kozorezov A. , Martin D. , van Dordrecht A. , Wigmore J. K. , Peacock A.
Published: November 2002

Multiple tunneling of quasiparticle charge carriers in a superconducting tunnel junction (STJ) enhances the signal generated by a photon absorption event. It is also an additional source of noise, responsible for a substantial degradation of the energy resolution. Although tunneling is a binomial chance process, governed by a constant tunneling probability, the resulting cumulative statistics of tunnelled quasiparticles depend on time. In particular, the variance of the total number of tunneled quasiparticles reaches a minimum after a finite integration time, corresponding to a minimum in the spectral linewidth. Since the intrinsic energy resolution of the present generation of STJs is mainly limited by the scatter on the number of tunneled quasiparticles, the improvement of the tunnel noise can be experimentally tested by variation of the pulse integration time. An analytical theory is developed that describes the relation between the tunnel noise and the transfer function of the pulse integration hardware for an STJ characterized by a quasiparticle tunnel and loss time in each electrode. We present experiments that demonstrate that the noise contribution from multiple tunnelling is not constant during the time that the quasiparticles are present in the STJ, and that by proper filtering of the STJ pulses the tunnel noise can be optimized at a level which lies well below the canonical tunnel limit.
A form of bulk silicon consisting of “magic” clusters
Authors: Grass M. , Fischer D. , Mathes M. , Ganteför G. , Nielaba P.
Published: November 2002

Si 4 clusters are soft-landed on an inert Van-der-Waals surface and the island formation is studied using x-ray and ultraviolet photoelectron spectroscopy. The experimental data indicate that the clusters do not fuse to Si islands but survive as individuals. The potential-energy surface of two Si clusters is calculated and a barrier against fusion is found, in agreement with the experiments. Both findings support the existence of a form of silicon consisting of Si4 clusters.
Vibronic structure of CCS in the Ã 3Πi state studied by laser-induced fluorescence spectroscopy
Authors: Nakajima Masakazu , Sumiyoshi Yoshihiro , Endo Yasuki
Published: November 2002

Laser-induced fluorescence spectrum of the Ã 3Πi←X̃ 3Σ− transition of the CCS radical has been studied in a discharged supersonic jet of a mixture gas, carbon disulfide and acetylene diluted in Ar. More than 40 vibronic bands in the 600–925 nm region have been assigned to the transitions from the ground vibronic level of the CCS radical. The progression of the C–C stretching mode was identified for υ1=1–4, and the harmonic frequency of the mode was determined to be 1840.13(1) cm−1. In addition to the perpendicular bands, Σ–Σ parallel-type bands have been observed and assigned to vibronically forbidden transitions, Ã(υ1,0,1)←X̃(0,0,0). Based on the positions of the bands, the harmonic frequency and the Renner parameter of the bending mode in the Ã 3Πi state were determined to be 399.00(3) cm−1 and −0.234 67(7), respectively. High-level ab initio calculations were performed to compare the results with the experimentally determined vibronic parameters. Since the band at 778 nm has a complicated rotational structure due to the overlap of vibronic levels, a microwave-optical double-resonance method using a Fourier-transform microwave spectrometer and a pulsed laser was applied to obtain a definite rotational assignment.
Parametric investigation of miniaturized cylindrical and annular Hall thrusters
Authors: Smirnov A. , Raitses Y. , Fisch N. J.
Published: November 2002

Conventional annular Hall thrusters become inefficient when scaled to low power. An alternative approach, a 2.6 cm miniaturized cylindrical Hall thruster with a cusp-type magnetic field distribution, was developed and studied. Its performance was compared to that of a conventional annular thruster of the same dimensions. The cylindrical thruster exhibits discharge characteristics similar to those of the annular thruster, but it has a much higher propellant ionization efficiency. Significantly, a large fraction of multicharged xenon ions might be present in the outgoing ion flux generated by the cylindrical thruster. The operation of the cylindrical thruster is quieter than that of the annular thruster. The characteristic peak in the discharge current fluctuation spectrum at 50–60 kHz appears to be due to ionization instabilities. In the power range 50–300 W, the cylindrical and annular thrusters have comparable efficiencies (15%–32%) and thrusts (2.5–12 mN). For the annular configuration, a voltage less than 200 V was not sufficient to sustain the discharge at low propellant flow rates. The cylindrical thruster can operate at voltages lower than 200 V, which suggests that a cylindrical thruster can be designed to operate at even smaller power.
Multidimensional spectroscopic probes of single molecule fluctuations
Authors: Barsegov Valeri , Mukamel Shaul
Published: November 2002

Single photon counting time distributions obtained from single molecule photon arrival trajectories are employed in the theoretical study of multistate kinetics coupled to a two-state jump bath. The bath time scale may be extracted from statistical analysis of one- and two-point time-domain optical measurements. The amplitude and shape of the distribution of interphoton arrival times reflects bath correlations. A slow bath (relative to the kinetics) results in broad distributions of arrival times reflecting bath memory. For a fast bath, the arrival time distributions narrow around shorter times, similar to motional narrowing in frequency domain spectroscopy. The variance of either kinetic rates or equilibrium population of bath states results in asymmetry of the distribution of two photon arrival times.
An analytical model for vibrational non-Born–Oppenheimer induced electron ejection in molecular anions
Authors: Simons Jack
Published: November 2002

We introduce an analytical model designed to capture the most important features of the electronic matrix elements arising in non-Born–Oppenheimer couplings between a bound anion state and a neutral-molecule-plus-ejected-electron state. In this particle-in-a-radial-box model, vibrations are assumed to cause modulations in the depth (U0) and length (L) parameters of the box. The most important elements of this model are that L is chosen to reproduce the proper dependence of the radial size of the anion’s orbital on electron binding energy, and U0 is chosen to produce the correct electron affinity. Within this model, which is shown to be consistent with trends seen in ab initio calculations of associated electron ejection rates, the coupling matrix elements can be evaluated analytically to provide closed-form expressions for how the rates depend upon (1) the kinetic energy of the ejected electron, (2) the energy spacing between the anion and neutral energy surfaces as a function of geometry, (3) the difference in the slopes of the anion and neutral energy surfaces, and (4) overlaps of the neutral’s vibration–rotation wave function with the spatial derivative of that of the anion.
Effect of composition and poling field on the properties and ferroelectric phase-stability of Pb(Mg1/3Nb2/3)O3–PbTiO3 crystals
Authors: Guo Yiping , Luo Haosu , Chen Kepi , Xu Haiqing , Zhang Xiaowen , Yin Zhiwen
Published: November 2002

Piezoelectric constant and temperature vs dielectric constant measurements have been performed on the 〈001〉 and 〈011〉 oriented Pb(Mg1/3Nb2/3)O3–PbTiO3 crystals in the rhombohedral phase with compositions near the morphotropic phase boundary under different poling fields. The investigations have revealed that the dielectric and piezoelectric properties strongly depend on composition (PbTiO3 content), and on poling field for crystals in a narrow composition region. The influence of composition on the stability of orthorhombic ferroelectric phase has been identified by x-ray diffraction on the 〈011〉 oriented crystals. And the origin of high piezoelectric response for crystals in different composition regions was proposed.
Enhanced emission mode of a ferroelectric plasma cathode
Authors: Chirko K. , Krasik Ya. E. , Felsteiner J. , Sternlieb A.
Published: November 2002

An enhanced electron emission mode of the ferroelectric plasma cathode operation is reported. The enhanced emission is achieved due to the generation of a dense plasma (1013–1014 cm−3) by the ionization of a thin neutral layer. The neutral layer is formed by a desorption process that accompanies the generation of a surface flashover plasma which has been induced by a driving current pulse applied to the ferroelectric sample. It was found that the application of a second driving current pulse with a several hundred μs delay with respect to the first driving current pulse causes an intense and uniform ionization of this neutral layer. Fast framing photographs of the light emission from this plasma and some parameters of the plasma and neutral flows are reported. Diode parameters were investigated under an accelerating voltage of 150–300 kV and pulse duration of 350 ns. Generation of an electron beam with current amplitude up to 2.5 kA is demonstrated. Also, it is shown that using the ferroelectric cathode in a reflex triode configuration allows the generation of high-power microwaves at a much smaller diode current amplitude as compared with explosive emission cathodes.
Bulk and surface properties of layered silicates/fluorinated polyimide nanocomposites
Authors: Jiang Liang-You , Wei Kung-Hwa
Published: November 2002

Intercalated layered silicates/fluorinated polyimide nanocomposites with good overall properties are synthesized from organics-modified-montmorillonite and poly(amic acid), as confirmed by x-ray and transmission electron microscopy results. Both the bulk and surface (nanometer-domain) mechanical properties of synthesized silicates/fluorinated polyimide nanocomposites increased substantially as compared to that of pure polyimide. In particular, the Young's modulus and surface hardness of the fluorinated polyimide containing 5 wt % 2NH2-mont are 69% and 100% larger than that of pure polyimide, respectively. Additionally, the reduced elastic modulus by nanoindentation of the nanocomposites is 74% larger than that of the pure polyimide. The barrier properties of the nanocomposites, such as thermal expansion and water absorption retardation, are enhanced.