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We present first-principles calculations of quantum transport which show that the resistance of metallic carbon nanotubes can be changed dramatically with homogeneous transverse electric fields if the nanotubes have impurities or defects. The change of the resistance is predicted to range over more than 2 orders of magnitude with experimentally attainable electric fields. This novel property has its origin that backscattering of conduction electrons by impurities or defects in the nanotubes is strongly dependent on the strength and/or direction of the applied electric fields. We expect this property to open a path to new device applications of metallic carbon nanotubes.

We used simulations with a classical force field to study the transformation under hydrostatic pressure of isolated single-walled nanotubes (SWNT) from a circular to a collapsed cross section. Small-diameter SWNTs deform continuously under pressure, whereas larger-diameter SWNTs display hysteresis and undergo a first-order-like transformation. The different behavior is due to the changing proportions in the total energy of the wall-curvature energy and the van der Waals attraction between opposite walls of the tube.

Objectives: To assess the impact of obesity on quality of life (QOL) in black and white adolescents., Study Design: One hundred ten overweight (body mass index [BMI], 41.7 +/- 8.9 kg/m2) and 34 nonoverweight adolescents (BMI, 20.6 +/- 2.9 kg/m2) and their parents completed measures of QOL., Results: Overweight was associated with poorer adolescent-reported QOL and parent reports of their children's QOL. Examining groups by weight status and race, overweight whites reported the greatest impairment on Social/Interpersonal, Self-Esteem, and Physical Appearance QOL (all P < .01), whereas parents of overweight blacks reported the poorest General Health Perceptions scores regarding their children. Interactions between BMI z-score and race were detected for Social/Interpersonal, Self-esteem, Daily Living, Self-Efficacy, Self-regard, and Physical Appearance QOL (all P < .05): Higher BMI in whites was associated with greater impairments in QOL than in blacks. Parents reported similar relations for their children., Conclusions: According to adolescent and parent reports, overweight is associated with poorer QOL in adolescence, regardless of race; however, compared with overweight white adolescents, blacks report less impairment in QOL. Future research is required to determine whether differences in QOL are predictive of treatment success.

Purpose: To examine the relationship of body weight to satisfaction with care in adolescents, and to obtain qualitative data on preferences for general and weight-related medical care in normal weight and overweight adolescents., Methods: The Weight and its Relationship to Adolescent Perceptions of their Providers survey, a 4-page questionnaire containing previously validated satisfaction scales and open-ended qualitative questions regarding health care preferences, was administered to 62 severely overweight (body mass index [BMI] 38.9 +/- 8.4 kg/m2) and 29 normal weight (BMI 22.5 +/- 4.0 kg/m2) adolescents (age 13.9 +/- 1.7 years; 57% female; 50% Caucasian, 47% African-American, 3% Hispanic)., Results: The affective subscale of the medical satisfaction scale was negatively correlated with BMI standard deviation score (r = -.22, p < .05). Multiple regression models predicting affective satisfaction with medical care included BMI standard deviation score; however, continuity with provider appeared to be the strongest independent predictor of affective satisfaction. Fifty-five percent of participants identified their mother as the person they felt most comfortable talking with about weight, although 68% believed their provider knew the most about healthy eating. "Overweight" was identified by 47% of participants as the preferred term for heavy teens. Seventy-nine percent of overweight adolescents stated their health care provider discussed their weight with them; however, only 41% of overweight adolescents desired to discuss their weight. Compared to normal-weight adolescents, overweight teens were more likely to report that their provider raised topics of weight (p < .001), diet (p < .01), and exercise (p < .01) at their last physical, and were more likely to report that they would have liked their provider to discuss diet and exercise (both p < .05). Ten percent of overweight teens expressed concerns regarding the public location of their provider's office scale., Conclusions: Satisfaction with affective aspects of the provider-patient relationship is negatively correlated with BMI standard deviation score. Length of experience with one's provider is also a strong predictor of teen satisfaction with their medical care. Teens prefer the term "overweight" for those with high body weight. Sensitivity to confidentiality, privacy, and embarrassment regarding physical examination and weight are important for teen satisfaction.

A method for calculating the phonon self-energy in metals arising from the coupling between phonons and electrons near the Fermi surface is developed. The essence of this scheme is the separation of the inter- and intraband parts of the electron polarizability. The intraband contribution provides extra screenings and is closely related to the electron-phonon coupling and phonon softening in metals. Applications of this scheme to phonons in MgB2 give excellent results when compared with experiments and previous theoretical work. In addition, both electron and hole dopings are found to reduce the renormalization effect of the E(2g) phonon mode, which indicates a weakened electron-phonon coupling in the doped systems.

In infants, a common consequence of systemic perinatal insults is disruption of neonatal brain development. Such insults can cause cerebral palsy, cognitive delay, epilepsy and other chronic neurologic deficits in children. The mechanisms underlying disruption of brain development after perinatal insults are poorly defined. To mimic human systemic insults, a transient prenatal hypoxic-ischemic insult model was developed in rodents. Ischemic animals showed reproducible histological lesions including oligodendrocyte loss, gliosis, and axonal disruption. Ischemic animals displayed persistent postnatal loss of oligodendrocyte lineage cells and cortical neurons, decreased cell proliferation, increased cell death, elevated pro-inflammatory cytokine levels, and impaired motor skills as young adults. Progressive ischemic intervals produced a graded pattern of injury. This systemic rodent prenatal hypoxic-ischemic insult accurately models human perinatal brain injury in several important criteria, including functional association of altered brain development with motor delay, and consequently provides novel insights into the pathogenesis of human perinatal brain insults.

Objective: To compare the effectiveness of exercise therapy aimed at restoring neuromuscular control mechanisms at the shoulder with other conservative interventions for the treatment of chronic shoulder pain with and without accompanying stiffness., Design: Randomized control trial., Patients: A total of 138 volunteers with unilateral shoulder pain of local mechanical origin., Methods: Subjects were randomly allocated to receive exercise therapy aimed at restoring dynamic stabilizing mechanisms and muscle co-ordination at the shoulder; or subacromial corticosteroid injection; or a combination of physical modalities and range of motion exercises. Outcome measurements of pain intensity, functional impairment, active range of motion, isometric muscle force and self-assessed improvement were taken at baseline and after 5 weeks of treatment., Results: The mean/median changes in all outcome measurements at 5 weeks indicated that subjects in each treatment group, improved significantly with no difference between the treatment groups. Comparison with an earlier no-treatment trial would suggest that this improvement is greater than that which could be expected by natural recovery., Conclusion: Exercise therapy aimed at restoring neuromuscular control, corticosteroid injection and multiple physical modalities and range of motion exercises are equally effective in the short-term treatment of shoulder pain, with exercise therapy and corticosteroid injection being less costly to administer.

Bias dependent scanning tunneling microscopy and scanning tunneling spectroscopy have been used to characterize the influence of transverse electric fields on the electronic properties of boron-nitride nanotubes (BNNTs). We find experimental evidence for the theoretically predicted giant Stark effect. The observed giant Stark effect significantly reduces the band gap of BNNTs and thus greatly enhances the utility of BNNTs for nanoscale electronic, electromechanical, and optoelectronic applications.

The temperature dependence of the band gap of semiconducting single-wall carbon nanotubes (SWNTs) is calculated by direct evaluation of electron-phonon couplings within a "frozen-phonon" scheme. An interesting diameter and chirality dependence of E(g)(T) is obtained, including nonmonotonic behavior for certain tubes and distinct "family" behavior. These results are traced to a strong and complex coupling between band-edge states and the lowest-energy optical phonon modes in SWNTs. The E(g)(T) curves are modeled by an analytic function with diameter- and chirality-dependent parameters; these provide a valuable guide for systematic estimates of E(g)(T) for any given SWNT. The magnitudes of the temperature shifts at 300 K are smaller than 12 meV and should not affect (n,m) assignments based on optical measurements.

Doping evolution of the Fermi surface topology of Na(x)CoO(2) is studied systematically. Both local density approximation (LDA) and local spin density approximation (LSDA) predict a large Fermi surface as well as small hole pockets for doping levels x approximately 0.5. In contrast, the hole pockets are completely absent for all doping levels within LSDA+U. More importantly, we find no violation of Luttinger's rule in this system. The measured Fermi surface of Na(0.7)CoO(2) can be explained by its half-metallic behavior and agrees with our LSDA+U calculations.

We have developed a novel iterative experimental-theoretical technique which can identify the atomic structure of defects in many-atom nanoscale materials from scanning tunneling microscopy and spectroscopy data. A given model for a defect structure is iteratively improved until calculated microscopy and spectroscopy data based on the model converge on the experimental results. We use the technique to identify a defect responsible for the electronic properties of a carbon nanotube intramolecular junction. Our technique can be extended for analysis of defect structures in nanoscale materials in general.

We observe, with angle-resolved photoemission, a dramatic change in the electronic structure of two C60 monolayers, deposited, respectively, on Ag (111) and (100) substrates, and similarly doped with potassium to half filling of the C60 lowest unoccupied molecular orbital. The Fermi surface symmetry, the bandwidth, and the curvature of the dispersion at Gamma point are different. Orientations of the C60 molecules on the two substrates are known to be the main structural difference between the two monolayers, and we present new band-structure calculations for some of these orientations. We conclude that orientations play a key role in the electronic structure of fullerides.

Objective: The assessment of eating-disordered behaviors in middle childhood is challenging. Frequently, both child and parents are queried about the child's eating behavior. However, no direct comparisons between parent and child reports of child eating disturbance have been published. We compared results from the adolescent and parent versions of the Questionnaire on Eating and Weight Patterns (QEWP-A and QEWP-P, respectively) in a nontreatment sample of overweight and normal weight children., Method: The QEWP-A and QEWP-P were administered to 142 overweight (body mass index [BMI] > or = 85th percentile) and 121 normal weight (BMI 15th-84th percentile) children, age 9.7 +/- 1.9 years, recruited from the community., Results: The QEWP-A and QEWP-P showed good agreement for the absence of eating-disordered behavior but were not concordant in terms of the number or type of binge eating, overeating episodes, or compensatory weight control behaviors in the past 6 months. Children categorized by their own reports (QEWP-A) as engaging in no overeating, simple overeating, or binge eating behaviors did not differ significantly in body composition or in eating and general psychopathology. Children categorized according to their parents' reports (QEWP-P) as engaging in binge eating had significantly greater body adiposity, eating-disordered cognitions, body dissatisfaction, and parent-reported problems (all ps <.001) than children engaging in no overeating or simple overeating according to the QEWP-P., Discussion: Child and parent reports of eating behaviors are not concordant regarding the presence of binge eating or compensatory behaviors. Further investigation of the utility of these questionnaires is needed before either can serve as a surrogate for a clinical interview.

Molecular dynamics simulations are used to study mechanical energy dissipation in carbon nanotube oscillators of lengths of tens of nanometers. The principal source of friction is found to be the ends of the tubes and hence dynamical friction is virtually independent of the overlap area between tubes. As a result of this, tube commensuration does not lead to significantly increased frictional forces. The friction force is found to depend strongly and nonlinearly on the relative velocity of the tubes. It is suggested that a strong velocity dependence and strong contributions from surface edges may be quite general features of friction at the nanoscale.

Purpose: Many children with refractory epilepsy can achieve better seizure control with surgical therapy. An abnormality on magnetic resonance imaging (MRI), along with corroborating localization by other modalities, markedly increases chances of successful surgical outcome. We studied the impact of high-resolution MRI on the surgical outcome of intractable epilepsy., Methods: High-resolution MRI using four-coil phased surface array was obtained as part of the comprehensive presurgical protocol for children with focal onset intractable seizures evaluated by our epilepsy center during the first half of 2002., Results: Thirteen consecutive children, ages 5 to 18 years, entered this prospective study. For four patients with a lesion on a recent MRI examination with a standard head coil, management did not change with high-resolution MRI. Standard MRI in the other nine patients did not identify a lesion. However, high-resolution MRI with the phased-array surface coil found previously undiagnosed focal abnormalities in five of nine patients. These abnormalities included hippocampal dysplasia, hippocampal atrophy, and dual pathology with frontal cortical dysplasia. In four of nine patients, no identifiable lesion was identified on the high-resolution MRI. All patients underwent invasive monitoring. In three of five patients, newly diagnosed lesions correlated with EEG abnormalities, and resection was performed., Conclusions: In our center, high-resolution MRI identified lesions not detected by standard MRI in more than half the children (56%). Technical advances such as four-coil phased surface array MRI can help identify and better delineate lesions, improving the diagnosis of patients who are candidates for surgical treatment of refractory epilepsy.

Objectives: To investigate the long-term clinical outcome and to identify factors that predict that outcome, after conservative treatment of patients who have shoulder pain with or without accompanying stiffness., Design: Cohort study., Setting: Outpatient clinic., Participants: Eighty-two subjects who had participated in a randomized controlled trial that compared the short-term effectiveness of conservative treatment for chronic, unilateral shoulder pain of mechanical origin with and without accompanying stiffness, and who were available for longer term follow-up 6 months after the cessation of formal treatment., Interventions: Conservative treatment consisting of various combinations of exercise therapy, passive joint mobilization, electrophysical modalities, and corticosteroid injections., Main Outcome Measures: Pain intensity, functional limitation, perceived change in symptoms, active range of motion, muscle force, and clinical and demographic variables., Results: Patients showed significant improvement in all outcome measurements in the long-term whether or not their shoulder pain was accompanied by stiffness. Long-term outcome was not predicted by hand dominance, clinical history of the shoulder condition, severity of the shoulder problem, or shoulder mechanics., Conclusions: Patients with chronic shoulder pain, with or without accompanying stiffness, can expect significant decreases in shoulder pain and improvements in shoulder function in the long term after conservative treatment.

Leucoencephalopathy with neuroaxonal spheroids (LENAS) is a rare disease of cerebral and cerebellar white matter. LENAS usually presents as a disorder of cognition and behaviour, or with gait dysfunction and ataxia. This report describes a patient who had a 14 year course of progressive neurological decline consistent with a clinical diagnosis of probable multiple system atrophy, with prominent cerebellar dysfunction and dysautonomia. Formal autonomic laboratory testing was consistent with global autonomic dysfunction of central origin. However, magnetic resonance imaging showed extensive white matter signal abnormalities, in addition to moderate cerebral and cerebellar atrophy. On postmortem microscopic examination, there were numerous axonal spheroids throughout the white matter of both regions. This case of LENAS presented unique clinical characteristics, and typical pathological findings.

Purpose: The unintentional and unrecognized cannulation of an extradural vein is a potentially serious complication of an epidural anesthetic. The present study was undertaken to assess the incidence of blood vessel puncture related to epidural catheterization in three different body positions, in a cohort of morbidly obese parturients, following the completion of a similar study published in 2001 from which such parturients were excluded., Methods: The study was conducted in 450 (three groups of 150) morbidly obese, obstetric patients undergoing continuous epidural analgesia during labour. Epidural catheterization was performed on patients randomized to the sitting, lateral recumbent horizontal, or lateral recumbent head-down position., Results: There was a lower incidence of vessel cannulation when this procedure was performed in the lateral recumbent head-down position [1.3%; body mass index (BMI): 37.0] than in the lateral recumbent horizontal [12.9%; BMI: 38.0] and in the sitting position [12.0%; BMI: 38.0]. The incidence of accidental subarachnoid puncture was 2%, 1.3% and 2% respectively, in these same positions., Conclusion: Adoption of the lateral recumbent head-down position for the performance of lumbar epidural blockade, in labour at term, reduces the incidence of lumbar epidural venous puncture in these obese parturients.

This study characterizes the sumatriptan-sensitive [5-hydroxytryptamine (5-HT)(1B/1D)] receptor in rabbit saphenous vein and basilar artery. (S)-(-)-1-[2-[4-(4-Methoxy-phenyl)-piperazin-1-yl]-ethyl]isochroman-6-carboxylic acid methylamide (PNU-109291), a 5-HT(1D) subtype-selective agonist (human K(i) = 2.5 +/- 0.07 nM), did not contract either tissue, whereas o-methoxyphenylpiperazide derivative 4F (MPPA-4F), a 5-HT(1B) subtype-selective antagonist (human K(i) = 4.6 +/- 0.6 nM) potently inhibited sumatriptan-induced contraction in the saphenous vein and basilar artery. These results suggested that sumatriptan-induced contraction was mediated via the 5-HT(1B) receptor in these blood vessels. 5-HT(1B) receptor-mediated contraction was then compared in endothelium-intact and denuded vessels to evaluate the role of the endothelium in regulating sumatriptan-induced contractility in these tissues. The presence of an intact endothelium inhibited 5-HT(1B)-induced contraction in both tissues. Endothelial denudation or nitric-oxide synthase inhibition with N(omega) nitro-L-arginine methyl ester (L-NAME) (100 microM) increased the efficacy and potency of sumatriptan in the saphenous vein and basilar artery. Surprisingly, in endothelial-denuded vascular tissues, L-NAME (100 microM) also significantly increased the maximal 5-HT(1B) receptor-induced contraction in both tissues, with no effect on potency of sumatriptan. The effect of L-NAME after endothelial denudation may reflect the presence of a low density of residual endothelial cells as estimated by CD31 antibody staining combined with the modulating effect of nitric oxide released from nonendothelial cells in vascular tissue. Endothelial modulation was specific to 5-HT(1B) receptors because removal of the endothelium did not significantly alter contraction to norepinephrine, histamine, prostaglandin, or potassium chloride in the saphenous vein or basilar artery.

We have calculated the phonon spectra of aluminum as a function of strain using density functional perturbation theory for <110>, <100>, and <111> uniaxial tension, as well as relaxed <112>[111] shear. In all four cases, phonon instabilities occur at points away from the center of the Brillouin zone and intrude before the material becomes unstable according to elastic stability criteria. This is the first time the ideal strength of a metal has been shown to be dictated by instabilities in the acoustic phonon spectra. We go on to describe the crystallography of the unstable modes, all of which are shear in character. This work further suggests that shear failure is an inherent property of aluminum even in an initially dislocation-free perfect crystal.

Compound 1a (LY334370), a selective 5-HT(1F) receptor agonist (SSOFRA), inhibited dural inflammation in the neurogenic plasma protein extravasation model of migraine and demonstrated clinical efficacy for the acute treatment of migraine. Although 1a was greater than 100-fold selective over both the 5-HT(1B) and 5-HT(1D) receptors, it exhibited appreciable 5-HT(1A) receptor affinity. Described here is the synthesis and evaluation of a series of pyrrolo[2,3-c]pyridine and pyrrolo[3,2-b]pyridine (2a and 3a) as well as pyrrolo[3,2-d]pyrimidine (4a) analogues of 1a, compounds prepared in an effort to identify SSOFRAs with improved selectivity over other 5-HT(1) receptor subtypes. The pyrrolo[3,2-b]pyridine analogue 3a showed high 5-HT(1F) receptor affinity but offered no improvement in selectivity compared to 1a. However, the C-5 acetamide derivative, 3b, was greater than 100-fold selective over the 5-HT(1A), 5-HT(1B), and 5-HT(1D) receptors. SAR studies of this series determined that alkylamides in particular exhibited high selectivity for the 5-HT(1F) receptor. Replacement at C-5 with other substituents decreased affinity or selectivity. These SAR studies identified SSOFRAs that demonstrated oral activity in the neurogenic plasma protein extravasation model, a model indicative of antimigraine activity.

C60 fullerides are challenging systems because both the electron-phonon and electron-electron interactions are large on the energy scale of the expected narrow band width. We report angle-resolved photoemission data on the band dispersion for an alkali-doped C60 monolayer and a detailed comparison with theory. Compared to the maximum bare theoretical band width of 170 meV, the observed 100-meV dispersion is within the range of renormalization by electron-phonon coupling. This dispersion is only a fraction of the integrated peak width, revealing the importance of many-body effects. Additionally, measurements on the Fermi surface indicate the robustness of the Luttinger theorem even for materials with strong interactions.

Muscarinic receptors can mediate both contractile and relaxant responses in smooth muscle. The stomach fundus from wild-type mice possesses a neuronal M(1) receptor that mediates relaxation to carbamylcholine and (4-hydroxy-2-butynyl)-1-trimethylammonium-3-chlorocarbanilate chloride (McN-A-343) but is masked by M(3) receptor-mediated contraction to both agonists. When the M(3) receptor was deleted, cholinergic-induced relaxation was unmasked. M(1) receptor antagonism with pirenzepine, nitric oxide (NO) synthase inhibition with N(omega)-nitro-L-arginine methyl ester hydrochloride, and inhibition of neuronal activation with tetrodotoxin abolished relaxation to McN-A-343 in tissues from M(3) receptor knockout mice, supporting the neuronal localization of an M(1) receptor that activated NO release to effect relaxation. However, the cyclooxygenase inhibitor indomethacin did not affect contraction or relaxation to carbamylcholine in stomach fundus from wild-type or M(3) receptor knockout mice, indicating that cyclooxygenase products played no role in these responses. The neuronal M(1) receptor modulated relaxation induced by carbamylcholine and McN-A-343 but not relaxation induced by electric field stimulation of the stomach fundus. These data support the presence of M(1) receptor-mediated relaxation in the stomach and suggest that when the M(3) receptor is eliminated or blocked, M(1) receptor-mediated gastric relaxation may be enhanced, possibly leading to alterations in gastric emptying and subsequent effects on body weight.

The modulation of serotonin (5-HT(1B/1D)) receptor-induced vascular contractility by histamine and U-46619 was compared in the rabbit basilar artery and saphenous vein. In the saphenous vein, histamine (5 x 10(-7) M) significantly increased the potency (from pEC(50) of 6.0 to 6.8) and efficacy (from 52.3% to 88.2%) of sumatriptan. Likewise, U-46619 (5 x 10(-9) M) also increased the potency (from pEC(50) of 5.9 to 6.6) and efficacy (from 51.8% to 92.1%) of sumatriptan in the saphenous vein. In contrast, equieffective concentrations of histamine (10(-7) M) and U-46619 (3 x 10(-9) M) failed to amplify contraction to sumatriptan in the basilar artery. Contraction to sumatriptan was inhibited by nitrendipine (10(-7) M) in the basilar artery but not in the saphenous vein, suggesting that different contractile signaling mechanisms are operating in these tissues. Furthermore, U-46619- and thrombin-induced contractility in the basilar artery were also not amplified by histamine, suggesting that lack of amplification of contraction in the basilar artery was not restricted to sumatriptan but was rather a characteristic of this cerebral vessel. These data suggest that in the in vivo plasma milieu sumatriptan will more markedly contract the peripheral saphenous vein than the basilar artery, a cerebral blood vessel.

We retrospectively studied the expression of cathepsin D by immunohistochemical analysis in 86 meningiomas (World Health Organization [WHO] grade I, n = 44; WHO grade II, n = 21; WHO grade III, n = 21) and correlated the results with tumor grade and outcome. Staining was scored semiquantitatively based on distribution among neoplastic cells as follows: 0, no staining; 1+, 5% or less of the cells; 2+, 6% to 20%; 3+, 21% to 50%; and 4+, more than 50% of the cells. Cathepsin D expression was observed as follows: 0, 10 cases (12%); 1+, 25 cases (29%); 2+, 15 cases (17%); 3+, 12 cases (14%); and 4+, 24 cases (28%). A higher degree of cathepsin D immunostaining was associated with low tumor grade (P = .0014), low mitotic count (P < .0001), low apoptotic count (P < .0001), and the development of recurrence (P = .035). There was no correlation with outcome or MIB-1 proliferation index. Cathepsin D expression by immunohistochemical analysis was identified in the majority (88% [76/86]) of meningiomas studied. A greater degree of immunoreactivity was observed in the WHO grade I group.

The biological attacks with powders containing Bacillus anthracis sent through the mail during September and October 2001 led to unprecedented public health and law enforcement investigations, which involved thousands of investigators from federal, state, and local agencies. Following recognition of the first cases of anthrax in Florida in early October 2001, investigators from the Centers for Disease Control and Prevention (CDC) and the Federal Bureau of Investigation (FBI) were mobilized to assist investigators from state and local public health and law enforcement agencies. Although public health and criminal investigations have been conducted in concert in the past, the response to the anthrax attacks required close collaboration because of the immediate and ongoing threat to public safety. We describe the collaborations between CDC and FBI during the investigation of the 2001 anthrax attacks and highlight the challenges and successes of public health and law enforcement collaborations in general.

Magnesium diboride differs from ordinary metallic superconductors in several important ways, including the failure of conventional models to predict accurately its unusually high transition temperature, the effects of isotope substitution on the critical transition temperature, and its anomalous specific heat. A detailed examination of the energy associated with the formation of charge-carrying pairs, referred to as the 'superconducting energy gap', should clarify why MgB(2) is different. Some early experimental studies have indicated that MgB(2) has multiple gaps, but past theoretical studies have not explained from first principles the origin of these gaps and their effects. Here we report an ab initio calculation of the superconducting gaps in MgB(2) and their effects on measurable quantities. An important feature is that the electronic states dominated by orbitals in the boron plane couple strongly to specific phonon modes, making pair formation favourable. This explains the high transition temperature, the anomalous structure in the specific heat, and the existence of multiple gaps in this material. Our analysis suggests comparable or higher transition temperatures may result in layered materials based on B, C and N with partially filled planar orbitals.

Negative chronotropic and smooth muscle contractile responses to the nonselective muscarinic agonist carbamylcholine were compared in isolated tissues from M(3)-muscarinic receptor knockout and wild-type mice. Carbamylcholine (10(-8)-3.0 x 10(-5) M) induced a concentration-dependent decrease in atrial rate that was similar in atria from M(3)-receptor knockout and wild-type mice, indicating that M(3) receptors were not involved in muscarinic receptor-mediated atrial rate decreases. In contrast, the M(3) receptor was a major muscarinic receptor involved in smooth muscle contraction of stomach fundus, urinary bladder, and trachea, although differences existed in the extent of M(3)-receptor involvement among the tissues. Contraction to carbamylcholine was virtually abolished in urinary bladder from M(3)-receptor knockout mice, suggesting that contraction was predominantly due to M(3)-receptor activation. However, approximately 50-60% maximal contraction to carbamylcholine occurred in stomach fundus and trachea from M(3)-receptor knockout mice, indicating that contraction in these tissues was also due to M(2)-receptor activation. High concentrations of carbamylcholine relaxed the stomach fundus from M(3)-receptor knockout mice by M(1)-receptor activation. Thus M(3)-receptor knockout mice provided unambiguous evidence that M(3) receptors 1) play no role in carbamylcholine-induced atrial rate reduction, 2) are the predominant receptor mediating carbamylcholine-induced urinary bladder contractility, and 3) share contractile responsibility with M(2) receptors in mouse stomach fundus and trachea.

Muscarinic receptors play a major role in gallbladder function, although the muscarinic receptor(s) mediating smooth muscle contractility is unclear. This study compared smooth muscle contractile responses to carbamylcholine (10(-7)-10(-3) M) in isolated gallbladder from wild-type and M(2), M(3), and M(4) receptor knockout mice. Carbamylcholine-induced contraction in gallbladder was associated with tachyphylaxis and the release of a cyclooxygenase product because indomethacin (10(-6) M) inhibited carbamylcholine-induced contraction. The M(3) receptor was the major muscarinic receptor involved in contraction because carbamylcholine-induced contractility was inhibited in gallbladder from M(3) receptor knockout mice. Furthermore, the muscarinic receptor antagonists 11-[[[2-diethylamino-O-methyl]-1-piperidinyl]acetyl]-5,11-dihydrol-6H-pyridol[2,3-b][1,4]benzodiazepine-6-one (AF-DX 116) and pirenzepine dextrally shifted contraction to carbamylcholine in gallbladder from wild-type, M(2), and M(4) receptor knockout mice, with affinities consistent with M(3) receptor interaction. In addition, maximal contraction to carbamylcholine was reduced in gallbladder from M(2) receptor knockout mice and affinities for AF-DX 116 and pirenzepine in gallbladder from M(3) receptor knockout mice were consistent with their affinities at M(2) receptors. In M(4) receptor knockout mice, contraction to carbamylcholine was dextrally shifted, although the affinities for AF-DX 116 and pirenzepine in gallbladder from M(2) or M(3) knockout mice were not similar to their affinities at M(4) receptors. The M(4) receptor may serve as an accessory protein necessary for optimal potency of M(2) and M(3) receptor-mediated responses. Thus, muscarinic receptor knockout mice provided direct and unambiguous evidence that M(3), and to a lesser extent, M(2) receptors are the predominant muscarinic receptors mediating gallbladder contractility, and M(4) receptors appear necessary for optimal potency of carbamylcholine in gallbladder contraction.

Since 5-HT1B receptor mRNA was reported in rat aorta, and 5-HT1B receptor activation has been linked to vascular contraction, we explored sumatriptan-induced contractility and immunohistochemical density of 5-HT1B receptor protein in rat aorta. Sumatriptan (up to 10(-4) M), a 5-HT1B/1D receptor agonist, did not contract the endothelial intact or denuded rat aorta, even in the presence of L-NAME or after induction of modest tone with PGF2 alpha (10(-6) M). Sumatriptan also did not relax aortic preparations precontract with PGF2 alpha (3 x 10(-6) M) or phenylephrine (3 x 10(-7) M). Using a polyclonal antibody directed against the 5-HT1B receptor, minimal 5-HT1B receptor protein was detected in either the endothelium or smooth muscle of the rat aorta. However, dense 5-HT1B receptor protein was found in the vascular smooth muscle of the vasa vasorum supplying the aorta. Thus, the 5-HT1B receptor mRNA detected in tissue extracts of the rat aorta most likely reflects 5-HT1B receptor expression in the arterioles of the vasa vasorum. These studies support the link between the 5-HT1B receptor and vascular contraction in that the aorta with low density of 5-HT1B receptors lacked responses to sumatriptan, an agonist thought to contract blood vessels via 5-HT1B/1D receptors. Furthermore, caution must be observed when using 5-HT1B receptor mRNA to suggest receptor protein in tissues since this RT-PCR product may be derived predominantly from small blood vessels.

1-[2-[4-(6-fluoro-1H-indol-3-yl)-3,6-dihydro-1(2H)-pyridinyl]ethyl]-3-isopropyl-6-(methylsulphonyl)-3,4-dihydro-1H-2,1,3-benzothiadiazine-2,2-dioxide (LY393558) is a potent inhibitor of [3H]5-hydroxytryptamine ([3H]5-HT) uptake into rat cortical synaptosomes (pIC(50)=8.48+/-0.12). It produces a dextral shift of the 5-HT dose-response curves for the binding of GTPgamma[35S] to human 5-HT(1B) (pK(b)=9.05+/-0.14) and 5-HT(1D) (pK(b)=8.98+/-0.07) receptors and inhibits the contractile response of the rabbit saphenous vein to the 5-HT(1B/D) receptor agonist, sumatriptan (pK(b)=8.4+/-0.2). In addition, it is an antagonist at the 5-HT(2A) (pK(i)=7.29+/-0.19) and 5-HT(2B) (pK(i)=7.35+/-0.11) receptors. Presynaptic autoreceptor antagonist activity was demonstrated by its ability to potentiate the K(+)-induced outflow of [3H]5-HT from guinea pig cortical slices (pEC(50)=7.74+/-0.05 nM) in which the 5-HT transporter had been inhibited by a maximally effective concentration of paroxetine. It is concluded that LY393558 should be an effective antidepressant with the potential to produce an earlier onset of efficacy than selective serotonin uptake inhibitors.

The interaction of the psychotropic agent olanzapine with serotonin 5-HT(3) and 5-HT(6) receptors was investigated. Olanzapine did not contract the isolated guinea pig ileum, but blocked contractions induced by the 5-HT(3) receptor agonist 2-methyl serotonin (2-CH(3) 5-HT) with a pK(B) value of 6.38+/-0.03, close to the affinity of the 5-HT(3) receptor antagonist ondansetron. The atypical antipsychotic risperidone (1 microM) did not significantly inhibit 2-CH(3) 5-HT-induced contractions. Olanzapine had high affinity (pK(i)=8.30+/-0.06) for human 5-HT(6) receptors in radioligand binding studies. Olanzapine did not stimulate [35S]guanosine-5'-O-(3-thio)triphosphate ([35S]GTPgammaS) binding to the G protein G(s) in cells containing human 5-HT(6) receptors, but inhibited 5-HT-stimulated [35S]GTPgammaS binding (pK(B)=7.38+/-0.16). Among other antipsychotics investigated, clozapine antagonized 5-HT(6) receptors with a pK(B)=7.42+/-0.15, ziprasidone was three-fold less potent, and risperidone, quetiapine and haloperidol were weak antagonists. Thus, olanzapine was not an agonist, but was a potent antagonist at 5-HT(6) receptors and had marked antagonism at 5-HT(3) receptors.

We show that for specially designed linear dispersive media with one absorption line and one gain line the Sommerfeld precursors of a pulse can be amplified leading to an earlier detection of the signal. Also, we show that in some systems with one strong absorption line, a carefully placed gain resonance must induce a discontinuity in the imaginary part of the frequency dependent index of refraction and in the first derivative of its real part.

The current study examined the anxiolytic effects of cigarette smoking and chewing gum on urge to smoke, withdrawal, and anxiety in response to a public speaking task in 45 undergraduate smokers. Participants were asked to smoke, chew gum, or do nothing in response to the stressor. Participants completed measures of anxiety, withdrawal symptoms, and urge to smoke pre- and poststressor. The smoke group reported fewer urges to smoke pre- and poststressor than the other groups. The smoke and gum groups reported fewer withdrawal symptoms than did the control group poststressor. Chewing gum was helpful in managing levels of withdrawal symptoms compared with the control group. Groups did not differ on measures of anxiety. Results suggest that smoking in response to a stressor may not reduce levels of affective stress. Furthermore, chewing gum may be helpful in managing withdrawal symptoms in response to a stressor.

The ideal shear strength of transition metal carbides and nitrides is calculated with the use of the ab initio pseudopotential density functional method. The microscopic mechanism that limits the ideal strength is studied using full atomic and structural relaxation and the results of electronic structure calculations. It is shown that plasticity in perfect crystals can be triggered by electronic instabilities at finite strains. Our study explicitly demonstrates that the ideal strength in these materials is limited by the elastic instability which is in turn initiated by electronic instabilities. The potential application of alloy hardening due to the onset of instabilities at different strains is also discussed.

The active site tripeptide arginal inhibitor of thrombin, LY287045, was used to study thrombin-induced aortic relaxation and contraction, two responses that differ both pharmacologically and physiologically. Although thrombin (10(-7) M) and trypsin (10(-6) M) were tachyphylactic upon repeated administration, trypsin contracted the aorta following thrombin-induced contraction. LY287045 (10(-7) M) attenuated thrombin-induced vasorelaxation, but not vasoconstriction with -log K(B) of 8.4. LY287045 (10(-7) M) also attenuated vasorelaxation, but not vasoconstriction to trypsin, another serine-protease with a thrombin-like catalytic triad, with similar potency (-log K(B) = 8.6) to that for thrombin. Consistent with these vascular effects, LY287045 inhibited the protease activity of both thrombin and trypsin. To explore further the selective inhibitory effect of LY287045 on protease-induced relaxation, we examined the effect of LY287045 on the nitric oxide and prostacyclin pathways and found that LY287045 did not alter vascular responses mediated by nitric oxide or prostacyclin. Likewise, LY287045 did not exert a direct inhibitory effect on the relaxant protease-activated receptor (PAR) since relaxation to the PAR-2-activating peptide was not blocked. The selective effect of LY287045 to inhibit only protease-induced endothelial-dependent relaxation demonstrated that protease inhibition will not affect all protease responses equally. Furthermore, increases in trypsin and thrombin have been associated with inflammation and angiogenesis. To the extent that these findings suggest that LY287045 exhibit dual protease inhibition of endothelial responses, LY287045 may have specific utility in hypotensive inflammatory diseases and in cancer metastases where both trypsin and thrombin have been implicated as causative agents.

Determination of muscarinic agonist-induced parasympathomimetic effects in wild type and M2 and M4 muscarinic receptor knockout mice revealed that M2 receptors mediated tremor and hypothermia, but not salivation. The M4 receptors seem to play a modest role in salivation, but did not alter hypothermia and tremor. In the M2 knockout mice, agonist-induced bradycardia in isolated spontaneously beating atria was completely absent compared to their wild type litter mates, whereas agonist-induced bradycardia was similar in the M4 knockout and wild type mice. The potency of carbachol to stimulate contraction of isolated stomach fundus, urinary bladder and trachea was reduced by a factor of about 2 in the M2 knockout mice, but was unaltered in the M4 knockout mice. The binding of the muscarinic agonist, [3H]-oxotremorine-M, was reduced in cortical tissue from the M2 knockout mice and to a lesser extent from the M4 knockout mice, and was reduced over 90% in the brain stem of M2 knockout mice. The data demonstrate the usefulness of knockout mice in determining the physiological function of peripheral and central muscarinic receptors.

The effects of vacancies on mechanical properties of the transition metal carbides and nitrides are studied using the ab initio pseudopotential approach. Calculated shear elastic stiffness and electronic structures show that the vacancy produces entirely different effects on the mechanical strength of groups IVb nitrides and Vb carbides. It is found that the occupation of shear-unstable metallic dd bonding states changes essentially in an opposite way for the carbides and nitrides in the presence of vacancies, resulting in different responses to shear stress. Our study provides an atomistic understanding of the anomaly in hardness for these substoichiometric materials.

Background and Objective: The effect of anaesthesia induced by intrathecal injection of 6.3% MgSO4 or 4% lidocaine on intracellular electrolyte homeostasis in spinal cord neurones of a rat model was investigated., Methods: Intracellular Ca2+, Mg2+, Na+ and K+ concentrations were determined at different times after intrathecal administration of NaCl (saline, a control group), MgSO4 or lidocaine., Results: In both thoracic and lumbar spinal cord segments, Ca2+ concentrations rose significantly 30 min and 2 h after 6.3% MgSO4 injection, and after 24 h were still significantly increased compared with the values obtained from the control group which were subjected to sham 'anaesthesia' by saline injection (172, 121 and 108 ng mg-1 protein vs. control 23 ng mg-1 protein, respectively, in the thoracic segment and 222, 229 and 176 ng mg-1 protein vs. control 43 ng mg-1 protein, respectively, in the lumbar segment). Lidocaine injection also produced a significant increase in intracellular Ca2+ in the thoracic and lumbar spinal cord segments (69, 64 and 53 ng mg-1 protein vs. control 33.4 ng mg-1 protein and 26, 94 and 46 ng mg-1 protein vs. 23 ng mg-1 protein respectively). Only a modest rise in intracellular Mg2+ was observed after intrathecal MgSO4 or lidocaine injection (27 ng mg-1 protein vs. 23 ng mg-1 protein). Na+ and K+ concentrations decreased 24 h after MgSO4 and 1 h after lidocaine injection., Conclusion: Intrathecal anaesthesia by MgSO4 or lidocaine alters intracellular electrolyte homeostasis in spinal cord neurones of experimental rats. A possible common mechanism of action via Ca2+ ion channels is discussed.

Carbamylcholine, a nonselective muscarinic receptor agonist, and sabcomeline and xanomeline, functional M(1) receptor-selective agonists with high M(2) receptor affinities, were used to explore the relationship of the M(2) receptor affinity of these agonists to mouse atrial bradycardia and to understand the relationship of the high and low M(2) receptor affinity states to carbamylcholine-induced mouse atrial bradycardia. All three agonists produced bradycardia with sabcomeline (pEC(50) = 6.7) more potent than either carbamylcholine (pEC(50) = 5.9) or xanomeline (pEC(50) = 5.1). Sabcomeline and carbamylcholine produced a rapid, concentration-related bradycardia, which was antagonized by atropine with pK(B) values of 8.6 and 8.9, respectively. In addition, sabcomeline antagonized carbamylcholine-induced bradycardia (pK(B) = 7.48), indicating that sabcomeline was a partial agonist at M(2) receptors. In contrast, xanomeline (up to 10(-5) M), did not antagonize carbamylcholine-induced bradycardia, and atropine (3.0 x 10(-8) M) did not antagonize xanomeline-induced bradycardia, suggesting that xanomeline-induced bradycardia was not mediated by M(2) receptors. Analysis of receptor occupancy curves indicated that bradycardia resulted from the interaction of carbamylcholine with the low- rather than high-affinity state of the M(2) receptor and that sabcomeline was a partial agonist at M(2) receptors in mouse atria. In contrast, similar analysis for xanomeline using the receptor affinity of xanomeline at M(2) receptors (1.8 x 10(-8) M) was not consistent with classical receptor theory. These data document that 1) the low-affinity state of the M(2) receptor is responsible for muscarinic-induced atrial bradycardia, 2) sabcomeline was an M(2) receptor partial agonist, and 3) xanomeline-induced bradycardia was not mediated by activation of M(2) muscarinic receptors.

Two state-of-the-art computational approaches: quantum Monte Carlo and GW with exciton effects [GW-BSE (Bethe-Salpeter equation)] are employed to calculate ionization potentials, electron affinities, and first excited singlet and triplet energies for the silane and methane molecules. Results are in excellent agreement between these dramatically different approaches and with available experiment. The optically forbidden triplet excitation in silane is predicted to lie roughly 1 eV higher than previously reported. In the GW-BSE method, we demonstrate that inclusion of off-diagonal matrix elements in the self-energy operator is crucial for an accurate picture.

Crystalline silicon is an indirect-bandgap semiconductor, making it an inefficient emitter of light. The successful integration of silicon-based electronics with optical components will therefore require optically active (for example, direct-bandgap) materials that can be grown on silicon with high-quality interfaces. For well ordered materials, this effectively translates into the requirement that such materials lattice-match silicon: lattice mismatch generally causes cracks and poor interface properties once the mismatched overlayer exceeds a very thin critical thickness. But no direct-bandgap semiconductor has yet been produced that can lattice-match silicon, and previously suggested structures pose formidable challenges for synthesis. Much recent work has therefore focused on introducing compliant transition layers between the mismatched components. Here we propose a more direct solution to integrating silicon electronics with optical components. We have computationally designed two hypothetical direct-bandgap semiconductor alloys, the synthesis of which should be possible through the deposition of specific group-IV precursor molecules and which lattice-match silicon to 0.5-1% along lattice planes with low Miller indices. The calculated bandgaps (and hence the frequency of emitted light) lie in the window of minimal absorption in current optical fibres.

Insulin-like growth factor (IGF)-II is an important growth factor in development of the central nervous system. The purpose of this study was to evaluate expression of IGF-II and IGF receptor type 1 (IGFR1) in various pediatric brain tumors. Immunohistochemistry for IGF-II and IGFR1 was performed on 15 choroid plexus papillomas (CPPs) including 1 atypical CPP, 2 choroid plexus carcinomas (CPCs), 5 anaplastic ependymomas, 7 nonanaplastic ependymomas (simply referred to as "ependymoma"), 5 medulloblastomas, 1 cerebral neuroblastoma, and 1 atypical teratoid/rhabdoid tumor (ATRT) along with 10 non-neoplastic choroid plexus and 3 non-neoplastic ependymal linings. All non-neoplastic choroid plexus, CPPs, CPCs, anaplastic ependymomas, ATRT, 71% of ependymomas, and 67% of non-neoplastic ependymal linings showed cytoplasmic positivity for IGF-II, whereas all medulloblastomas and the cerebral neuroblastoma were negative for IGF-II. In addition to cytoplasmic positivity for IGFR1, membranous positivity was observed in 73% of CPPs, both CPCs, the ATRT, 22% of non-neoplastic choroid plexus, 80% of anaplastic ependymomas, and 29% of ependymomas, but not in any medulloblastoma, cerebral neuroblastoma, or non-neoplastic ependymal lining. IGF-II and IGFR1 may play roles in the pathogeneses of CPP, CPC, anaplastic ependymoma, ependymoma, and ATRT. Immunohistochemical testing for IGF-II and IGFR1 may be useful in differentiating ATRT, CPC, and anaplastic ependymoma from medulloblastoma and cerebral neuroblastoma.

Purpose: The unintentional and unrecognized cannulation of an extradural vein is a potentially serious complication of an epidural anesthetic. The present study was undertaken to assess the incidence of blood vessel puncture related to epidural catheterization performed in three different body positions., Methods: The study was conducted in 900 (three groups of 300) obstetric patients undergoing continuous epidural analgesia during their labour and who were randomly allocated to three groups. Epidural catheterization was performed with patients in the sitting, lateral recumbent horizontal, or lateral recumbent head-down position., Results: There was a lower incidence of vessel cannulation when this procedure was performed in the lateral recumbent head-down position (2%) than in the lateral recumbent horizontal (6%) and in the sitting position (10.7%)., Conclusion: Adoption of the lateral recumbent head-down position for the performance of lumbar epidural blockade, in labour at term, reduces the incidence of lumbar epidural venous puncture.

Background: We have previously reported that 1alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3] accumulates in the dialysis fluid of uremic patients treated by continuous ambulatory peritoneal dialysis (CAPD). It has been reported that this metabolite regulates the production of cytokines by monocytes/macrophages. Since tumor necrosis factor-alpha (TNF-alpha) initiates an inflammatory cascade during peritonitis, the aim of the present study was to investigate the effect of 1alpha, 25(OH)2D3 on the production of TNF-alpha by human peritoneal macrophages (HPMs)., Methods: HPMs were obtained from patients on CAPD. Cells were incubated with various concentrations of 1alpha, 25(OH)2D3, 1alpha,24(S) dihydroxyvitamin D2 [1alpha,24(S)(OH)2D2] or 25-hydroxyvitamin D3 (25-OH-D3) for 16 hours. This was followed by lipopolysaccharide (LPS; 1 microg/mL) incubation for 2.5 to 6 hours. TNF-alpha protein production was determined by enzyme-linked immunosorbent assay. TNF-alpha mRNA was assayed by the reverse transcriptase-polymerase chain reaction procedure, using internal synthetic mRNA standards for quantitative results., Results: Incubation of HPMs with 1alpha,25(OH)2D3 prior to stimulation with LPS dose dependently inhibited the expression of TNF-alpha on both mRNA and protein levels. Similar results were obtained with the less calcemic vitamin D2 analogue 1alpha,24(S)(OH)2D2. Incubation of HPMs with 25-OH-D3 also revealed a down-regulation of TNF-alpha expression. Since this down-regulatory effect was blocked by ketoconazole, it is likely that this effect was caused by the conversion of 25-OH-D3 into 1alpha,25(OH)2D3 by HPMs., Conclusions: 1alpha,25(OH)2D3 has a potent inhibitory effect on the production of TNF-alpha by LPS-activated HPMs. We hypothesize that 1alpha, 25(OH)2D3 may constitute a regulatory mechanism that, by controlling the intensity of the inflammatory response of the peritoneum, will moderate tissue damage during peritonitis.

The thermoelectric power (TEP) of single-walled carbon nanotubes (SWNTs) is extremely sensitive to gas exposure history. Samples exposed to air or oxygen have an always positive TEP, suggestive of holelike carriers. However, at fixed temperature the TEP crosses zero and becomes progressively more negative as the SWNTs are stripped of oxygen. The time constant for oxygen adsorption/desorption is strongly temperature dependent and ranges from seconds to many days, leading to apparently "variable" TEP for a given sample at a given temperature. The saturated TEP can be accounted for within a model of strong oxygen doping of the semiconducting nanotubes.

Contractile responses to ergotamine, sumatriptan and the novel 5-HT(1F) receptor agonists, LY334370 and LY344864 were examined using the rabbit saphenous vein. Ergotamine (pEC(50)=8.7+/-0.06) was 30 fold more potent than 5-hydroxytryptamine (5-HT) (pEC(50)=7.2+/-0.13) and 300 fold more potent than sumatriptan (pEC(50)=6.0+/-0.08) in contracting the rabbit saphenous vein in vitro. The selective 5-HT(1F) receptor agonists, LY334370 or LY344864 (up to 10(-4) M), did not contract the rabbit saphenous vein. The contractile response to ergotamine in this tissue resulted from activation of both alpha(1) and 5-HT(1B/1D) receptors based on the observation that prazosin (10(-6) M), an alpha-adrenoceptor antagonist, and GR127935 (10(-8) M) a 5-HT(1B/1D) receptor antagonist, dextrally shifted the contractile response to ergotamine. In contrast, prazosin (10(-6) M) did not alter contraction to sumatriptan whereas GR127935 (10(-8) M) was a potent antagonist (-log K(B)=10.0) suggesting that sumatriptan-induced contraction of the rabbit saphenous vein was mediated only by activation of receptors similar or identical to 5-HT(1B/1D) receptors. PGF(2alpha) (3x10(-7) M) produced a modest increase (approximately 5.0 - 10.0% maximum PGF(2alpha) contraction) in saphenous vein force. Precontraction with PGF(2alpha) (3x10(-7) M) dramatically augmented the potency and maximal contractile response to sumatriptan (pEC(50)=7.1) and modestly enhanced the contractile potency of ergotamine (pEC(50)=9.0) in the rabbit saphenous vein. However, PGF(2alpha) (3x10(-7) M) only unmasked a contraction to the 5-HT(1F) receptor agonists when concentrations exceeded 10(-5) M, concentrations considerably higher than their 5-HT(1F) receptor affinities. LY334370 (10(-6) M) pretreatment did not alter contraction to either sumatriptan or ergotamine and a higher concentration (10(-5) M) of LY334370 or LY344864 inhibited contraction to sumatriptan. Thus, activation of 5-HT(1F) receptors will not induce vascular contraction (either alone or following modest tone with PGF(2alpha)) or augment contraction to other contractile agonists in the rabbit saphenous vein.