Effectiveness of tramadol as an analgesic in oral surgery.

In a randomised, double-blind, cross-over trial, 15 healthy, young patients undergoing surgical removal of bilateral, impacted, third-molar teeth received the analgesic tramadol 50 mg, as a single dose, either 2 hours prior or immediately before the surgical procedure. There were no differences in the post-operative pain levels or degree of trismus between the two methods of administration of tramadol (P > 0.05), suggesting absence of any pre-emptive analgesic effect for the drug in the dose studied.

Modelling ion binding to AA platform motifs in RNA: a continuum solvent study including conformational adaptation.

Binding of monovalent and divalent cations to two adenine-adenine platform structures from the Tetrahymena group I intron ribozyme has been studied using continuum solvent models based on the generalised Born and the finite-difference Poisson-Boltzmann approaches. The adenine-adenine platform RNA motif forms an experimentally characterised monovalent ion binding site important for ribozyme folding and function. Qualitative agreement between calculated and experimental ion placements and binding selectivity was obtained.

Conformations of an adenine bulge in a DNA octamer and its influence on DNA structure from molecular dynamics simulations.

Molecular dynamics simulations have been applied to the DNA octamer d(GCGCA-GAAC). d(GTTCGCGC), which has an adenine bulge at the center to determine the pathway for interconversion between the stacked and extended forms. These forms are known to be important in the molecular recognition of bulges.

Conformational analysis of DNA-trinucleotide-hairpin-loop structures using a continuum solvent model.

A number of trinucleotide sequences in DNA can form compact and stable hairpin loops that may have significance for DNA replication and transcription. The conformational analysis of these motifs is important for an understanding of the function and design of nucleic acid structures. Extensive conformational searches have been performed on three experimentally known trinucleotide hairpin loops (AGC, AAA, and GCA) closed by a four-base-pair stem.

Comparison of molecular dynamics and harmonic mode calculations on RNA.

Conformational fluctuations of a double-stranded RNA oligonucleotide have been calculated from a two nanosecond molecular dynamics simulation including explicit waters and ions and from a harmonic mode analysis. The harmonic mode analysis was performed in the absence of solvent using various effective dielectric screening functions. RNA flexibility was analyzed and compared at the level of atomic position fluctuations, helical base-pair descriptor fluctuations and global helix bending, stretching, and twisting flexibilities.

Simulation of the structure and dynamics of nonhelical RNA motifs.

Computer simulation methods are increasingly being used to study possible conformations and dynamics of structural motifs in RNA. Recent results of molecular dynamics simulations and continum solvent studies of RNA structures and RNA-ligand complexes show promising agreement with experimental data. Combined with the ongoing progress in the experimental characterization of RNA structure and thermodynamics, these computational approaches can help to better understand the mechanism of RNA structure formation and the binding of ligands.

Conformational deformability of RNA: a harmonic mode analysis.

The harmonic mode analysis method was used to characterize the conformational deformability of regular Watson-Crick paired, mismatch- and bulge-containing RNA. Good agreement between atomic Debye-Waller factors derived from x-ray crystallography of a regular RNA oligonucleotide and calculated atomic fluctuations was obtained. Calculated helical coordinate fluctuations showed a small sequence dependence of up to approximately 30-50%.

Conformational analysis of single-base bulges in A-form DNA and RNA using a hierarchical approach and energetic evaluation with a continuum solvent model.

The analysis and prediction of non-canonical structural motifs in RNA is of great importance for an understanding of the function and design of RNA structures. A hierarchical method has been employed to generate a large variety of sterically possible conformations for a single-base adenine bulge structure in A -form DNA and RNA. A systematic conformational search was performed on the isolated bulge motif and neighboring nucleotides under the constraint to fit into a continuous helical structure.

Tenoxicam does not alter renal function during anaesthesia in normal individuals.

Background: Anaesthesia and surgery alter renal function. Inhibition of prostaglandin synthesis by non-steroidal anti-inflammatory drugs (NSAIDs) administered with anaesthesia may further compromise renal function.

Aim: To study the effects of tenoxicam (NSAID) administered immediately prior to anaesthesia on renal function in normal individuals undergoing routine surgery.

Stereoselective urinary excretion of bupivacaine and its metabolites during epidural infusion.

A sensitive and efficient chiral assay for bupivacaine and its three principal metabolites desbutylbupivacaine, 4'-hydroxybupivacaine, and 3'-hydroxybupivacaine has been applied to urine from five male patients receiving postoperative epidural infusions of rac-bupivacaine fentanyl over 60-120 hr. The fraction of the dose of bupivacaine (total dose 840-2093 mg) accounted for in urine was 75 +/- 6%. The rate of excretion of bupivacaine enantiomers' approximated a steady state after approximately 30 hr with values of 1.

Comparison of oral and intravenous routes of giving tenoxicam.

Twenty-five fit patients undergoing third molar surgery received the non-steroidal anti-inflammatory drug tenoxicam 40 mg given orally the night before surgery or intravenously at the time of surgery in a randomised, double-blind, cross-over trial. Propofol was used for intravenous sedation. Pain on injection was noted with propofol in 32-56 percent of subjects, but was mostly of minor nature.

[Equipment-independent ultrasound tissue characterization of testis and prostate].

The result of a B-scan ultrasound examination is strongly dependent on the type of the used B-system, the chosen system parameters and the experience and critical analysis of the clinical investigator. The estimation of quantitative acoustic parameters, independent of the type of the used B-system, is one way to overcome the subjective nature and the problems of the interpretation of B-scan images. A procedure was developed to determine acoustical tissue specific parameters (ultrasound attenuation, relative backscatter coefficient) in terms of the ultrasound spectroscopy and to correct the system effects.

Two methods of administration of propofol for dental sedation.

Propofol was used for intravenous sedation in a group of 19 healthy fit young patients undergoing third molar extractions. We compared two ways of giving the drug, patient-controlled and operator-controlled, in a crossover trial. There were no differences between the two methods.

Analysis of the stability of looped-out and stacked-in conformations of an adenine bulge in DNA using a continuum model for solvent and ions.

A combination of conformational search, energy minimization, and energetic evaluation using a continuum solvent treatment has been employed to study the stability of various conformations of the DNA fragment d(CGCAGAA)/d(TTCGCG) containing a single adenine bulge. The extra-helical (looped-out) bulge conformation derived from a published x-ray structure and intra-helical (stacked bulge base) model structures partially based on nuclear magnetic resonance (NMR) data were used as start structures for the conformational search. Solvent-dependent contributions to the stability of the conformations were calculated from the solvent exposed molecular surface area and by using the finite difference Poisson-Boltzmann approach.

Increased axon number in the anterior commissure of mice lacking a corpus callosum.

Relatively few behavioral deficits are apparent in subjects with hereditary absence of the corpus callosum (CC). The anterior commissure (AC) has been suggested to provide an extracallosal route for the transfer of interhemispheric information in subjects with this congenital defect. Anterior commissure size, axon number, axon diameter, and neuronal distribution were compared between normal mice and those with complete CC absence.

Influence of static and dynamic bends on the birefringence decay profile of RNA helices: Brownian dynamics simulations.

Bends in nucleic acid helices can be quantified in a transient electric birefringence (TEB) experiment from the ratio of the terminal decay times of the bent molecule and its fully duplex counterpart (tau-ratio method). The apparent bend angles can be extracted from the experimental tau-ratios through the application of static (equilibrium-ensemble) hydrodynamic models; however, such models do not properly address the faster component(s) of the birefringence decay profile, which can represent up to 80% of the total birefringence signal for large band angles. To address this latter issue, the relative amplitudes of the components in the birefringence decay profile have been analyzed through a series of Brownian dynamics (BD) simulations.

The absence of any pre-emptive analgesic effect for non-steroidal anti-inflammatory drugs.

Pre-emptive analgesic efficacy of the non-steroidal anti-inflammatory drug, diclofenac sodium, was tested in 21 young, fit, patients undergoing third molar extractions in a double-blind, randomised, cross-over, trial. Pain scores and mouth opening were observed for 1 week after the operation and these did not show any differences following pre- and postoperative oral administration of diclofenac sodium 100 mg (P > 0.05).

Respiratory effects of intravenous midazolam.

Thirty-four healthy, young-adult patients receiving intravenous midazolam for third-molar surgery had their respiratory parameters measured by respiratory inductive plethysmography. Tidal volume and minute volume showed significant changes during the initial 5-10 minutes of sedation, the changes being maximal during the first 5 minutes from the completion of injection of midazolam. The measurement of phase angle, an indicator of respiratory asynchrony, showed no significant change from normal, although a few patients showed some asynchrony of breathing, suggesting some amount of respiratory obstruction.

Effectiveness of preoperative analgesics on postoperative dental pain: a study.

Patients undergoing extractions of third molar teeth under general anesthesia were given a placebo, diclofenac (a nonsteroidal anti-inflammatory drug) 100 mg, or methadone (an opiate) 10 mg 60 to 90 min prior to surgery, and their pain scores and postoperative medication requirements were measured for 3 days. All patients received local anesthetic blocks and analgesic drugs during the perioperative period. There were no significant differences between the three groups in the pain scores and medication requirements during the period of study.

The influence of symmetric internal loops on the flexibility of RNA.

Internal loops are structural elements, often highly conserved, that are found in many RNA molecules of biological importance. They consist of short stretches of sequence in which the bases in one strand are not able to form canonical pairs with bases in the other strand, and are bounded on either side by helical RNA. In an effort to examine the influence of internal loops on the relative angular orientations of the flanking helices, we have quantified the apparent bend angles for symmetric internal loops of the form A(n)-A(n) and U(n)-U(n) (n=2, 4, and 6), located at the center of 150 to 154 bp RNA molecules, using the method of transient electric birefringence.

Nitrous oxide and the rate of gas uptake from an unventilated lung in dogs.

We have studied the effect of FIO2 of a nitrous oxide-oxygen mixture on the rate of gas uptake from an unventilated lung. Nine anaesthetized dogs were studied, each breathing four nitrous oxide-oxygen mixtures (FIO2 0.3, 0.