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At least 181 records · Page 10Linked to original sources
PubMed1997

Symptom-giving pelvic girdle relaxation of pregnancy, postnatal pelvic joint syndrome and developmental dysplasia of the hip. The Norwegian Association for Women with Pelvic Girdle Relaxation (Landforeningen for Kvinner Med Bekkenløsningsplager).

OBJECTIVES: To describe the clinical characteristics and outcomes of a large group of women with symptom-giving pelvic girdle relaxation of pregnancy and postnatal pelvic joint syndrome. To determine if there is an increased incidence of developmental dysplasia of the hip in the children of women with such pelvic problems. METHODS: A postal survey of 1,609 Norwegian women registered as having pregnancy-initiated pelvic joint pain. The response rate was 79% and from the answers 1,115 women were defined as having had symptom-giving pelvic joint syndrome of pregnancy and/or postnatal pelvic joint syndrome. RESULTS: Pelvic pains began in the first pregnancy in 74% of the respondents usually beginning in the first trimester. Pelvic pain worsened with subsequent pregnancies and persisted for a mean of 6.25 years, often causing major incapacity and lifestyle changes. Rest and physical supports brought temporary relief only. Sacroiliac joints and the symphysis pubis were the commonest sites of pain but peripheral joints were also often affected. There was a strong family history of both pelvic joint syndrome and developmental dysplasia of the hip. The incidence of hip dysplasia in the children of women surveyed was 45/1,000 which is 5 times the Norwegian incidence. CONCLUSION: Pelvic joint syndrome nearly always follows pelvic girdle relaxation of pregnancy and may have prolonged debilitating effects which do not respond long term to current therapies. The incidence of developmental dysplasia of the hip in the children of these women was high. A genetic susceptibility to joint dysfunction in both mother and fetus, possibly due to an aberration of relaxin physiology, is surmized. Identification of possible relaxin receptor changes in affected joints is a hypothesis worthy of testing with a view to the design of selective relaxin receptor modulators in pregnancy.

Adult↗
PubMed2000

Thapsigargin, a Ca(2+)-ATPase inhibitor, relaxes guinea pig tracheal smooth muscle by producing epithelium-dependent relaxing factors.

A non-phorbol ester-type tumor promoter, thapsigargin has been reported to deplete Ca(2+) stores in endothelial cells by inhibiting Ca(2+)-ATPase, which in turn increases intracellular Ca(2+) by mobilization of extracellular Ca(2+), leading to activation of constitutive nitric oxide synthase (cNOS) and resultant generation of nitric oxide (NO). In the present study, to evaluate the role of Ca(2+) in the release of epithelium-dependent relaxing factor (EpDRF), we determined the effect of thapsigargin (10(-6) M) on the contraction evoked by exogenous Ca(2+) or acetylcholine (10(-5) M) in epithelium-denuded or epithelium-intact smooth muscle from guinea pig trachea. The following results were obtained: (1) In epithelium-denuded smooth muscle, the contraction evoked by exogenous Ca(2+) in Ca(2+)-free solution or by acetylcholine (10(-5) M) in Ca(2+)-containing solution did not change within 20 min after thapsigargin application, but the contraction evoked by exogenous Ca(2+) increased markedly after 120 min, indicating that thapsigargin had no effect on smooth muscle itself within 20 min of application. The following experiments were performed within 20 min of thapsigargin application. (2) In epithelium-intact smooth muscle, thapsigargin significantly suppressed the contraction evoked by acetylcholine, suggesting that thapsigargin stimulate the epithelium to produce EpDRF. N(G)-nitro-L-arginine methylester (L-NAME) partly, but significantly, attenuated this inhibitory effect of thapsigargin. (3) In epithelium-denuded smooth muscle, atropine (10(-6) M) and L-NAME (10(-5) M) did not change the contraction evoked by exogenous Ca(2+) after application of thapsigargin, suggesting that thapsigargin did not stimulate acetylcholine and NO release from nerve terminals. These results suggest that thapsigargin (10(-6) M) may stimulate EpDRF, including NO and other factor(s) by Ca(2+)-dependent mechanisms.

Acetylcholine↗
PubMed1990

Placebo-controlled evaluation of abbreviated progressive muscle relaxation and of relaxation combined with cognitive therapy in the treatment of tension headache.

Sixty-six tension headache patients were randomly assigned to one of four conditions for 8 weeks: (a) progressive muscle relaxation (PMR) alone; (b) PMR plus cognitive therapy (PMR + Cog); (c) pseudomeditation, a credible attention-placebo control; or (d) continued headache monitoring. A comparison of overall headache activity (headache index), derived from a daily headache diary, for 4 weeks before treatment to 4 weeks after treatment, revealed that active treatment (PMR and PMR + Cog) was superior to either control condition. Moreover, level of headache medication consumption decreased significantly for the active treatment groups. Although headache-index comparisons of the two active treatments showed no advantage for adding cognitive therapy to PMR, a measure of clinically significant change showed a trend for PMR + Cog to be superior to PMR alone.

Adult↗
PubMed1976

Computer controlled muscle relaxation: a comparison of four muscle relaxants in the sheep.

Computer control of anaesthesia has been extended to include muscle relaxant drugs. Injection of d-tubocurarine, gallamine, alcuronium or pancuronium was controlled by computer to reduce the integrated electromyogram to a preset level (40 per cent of control) for one hour. A programmed level of muscle paralysis is therefore possible for use in physiological and pharmacological experiments, and in clinical practice where precise control of the degree of paralysis together with minimal dosage is advantageous.

Alcuronium↗
PubMed1980

[Muscle relaxants / 3rd communication: Development of acrylic acid derivatives of potential muscle relaxing activity (author's transl)].

With reference to the occurrence of C=C partial structures and alkyl carboxylate groupings in muscle relaxants, the synthesis of acrylic acid derivatives by the aminomethinylation procedure has been followed up. From the reaction of s-triazine (1) with methyl acetoacetate (2a) and piperidine (5a), methyl 2-acetyl-3-piperidino acrylate (6a) arises. Analogously, 3-pyrrolidinoacrylophenone (6b) and 3-morpholinoacrylophenone (6c) are formed. In the same manner, the three-component reaction comprising the interaction of 1 with malononitrile (7) and a secondary amine (5) gives rise to the formation of the aminomethylenemalononitrile structure 8.

Acrylates↗
PubMed2002

Dielectric relaxation on the intermediate layer in a bipolar membrane under the water splitting phenomenon. II. Double dielectric relaxation and identification of phase parameters.

In this study, we investigated the impedance spectra of bipolar membranes. Under the application of a reverse-biased voltage, the spectra showed a double dielectric relaxation profile due to the heterogeneous structure and it was analyzed in accordance with the three-layered dielectric model. It is defined that one of the compositions of the heterogeneous structure is situated at the membrane interface region between the negatively and the positively charged membrane with a thickness of less than several micrometers, which has an extraordinarily large electric capacity with a magnitude of sub-microfarads. It is concluded that this layer is identified with the intermediate layer in which the water splitting phenomenon occurs on the bipolar membrane.

Journal Article↗
PubMed1989

Measurement of ventricular relaxation. An alternative index of isovolumic relaxation to the time constant.

The time constant (T) is commonly used for representing the isovolumic fall in left ventricular pressure (LVP) because the isovolumic fall is monoexponential under most circumstances. However, the determination of T is cumbersome due to the requirement of a set of LVP versus time values in fitting a monoexponential function. RT64, which is the time from the minimum value of the time derivative of LVP (-dp/dtmax) to 36% of -dP/dtmax, can be derived beat-by-beat, on-line, and may be a simple alternative to T. Through the use of 240 pairs of values derived from six conscious instrumented dogs treated with different cardiovascular active agents, RT64 and T were found to be significantly correlated (r = 0.835, p less than 0.05) according to the equation RT64 = 0.725T + 10.2. In conclusion, RT64 may provide a simple alternative to T in representing the isovolumic relaxation process of the left ventricle.

Animals↗
PubMed1995

Use of relaxation agent doping to shorten very long spin-lattice relaxation times in a magic-angle turning experiment.

A practical method is described for measuring the principal values of the chemical shift tensors in compounds with very long proton spin-lattice relaxation times (T1). This technique involves shortening the effective proton T1. by mixing a compound of interest with another compound having a much shorter T1 value. The doped mixture, partly consisting of a monophasic glass, allows efficient intermolecular spin diffusion between the two compounds. Using a slow magic-angle turning (MAT) experiment, we have successfully used such mixtures to measure the principal values of the chemical shift tensors of all the carbons in dibenzofuran in just four days. Without using this technique the experimental time required for the pure compound would have been several months.

Benzofurans↗
PubMedDate not supplied

From porous media to trabecular bone relaxation analysis: spatial variation of marrow 1H relaxation time distributions detected in vitro by quasi-continuous distribution analysis.

Quasi-continuous distributions of T(1) and T(2) of 1H nuclei were analyzed in vitro at 20MHz on some twenty fresh bone samples of pig femur. Large numbers of data points allowed a detailed investigation. Relaxation data were inverted by UPEN (Uniform PENalty inversion). In all samples the widths of the distributions, covering more than two decades, are not even close to being compatible with single exponential components. Moreover, the T(1) and T(2) distributions show enough character to distinguish the samples. We observe a spatial variation of these characteristics and in particular a second peak centered at 500-600 ms appearing in some proximal femur samples. The quasi-continuous distribution allows one to correlate the water content of the sample with parts of the distributions in specific time ranges. The signal fraction with T(1) values longer than a cutoff time of about 170 ms is in very good agreement with the water content of the samples and is significantly larger in the group of samples cored from proximal femur. Also T(2) distributions differentiate the samples, and the signal fraction with T(2) shorter than about 30 ms is significantly larger in the group of distal femur samples.

Animals↗
PubMed1998

Magnetic resonance imaging relaxation times and gadolinium-DTPA relaxivity values in human cerebrospinal fluid.

RATIONALE AND OBJECTIVES: This study was conducted to prove the feasibility of using cerebrospinal fluid (CSF) T1 and T2 measurements to assess the blood-brain barrier integrity in disease states not noted for focal blood-brain barrier disruption, such as Alzheimer's disease. METHODS: T1 and T2 of human CSF samples were measured with and without gadolinium Gd-DTPA over a concentration range of 1.98 x 10(-3) to 6.32 mM, in a GE 1.5-T Signa scanner. RESULTS: T1 and T2 of human CSF without Gd-DTPA were measured as 2.39 and 0.23 s. K1 and K2 were calculated as 6.25 and 6.74 mM(-1) s(-1). The lowest Gd-DTPA concentration with measurable T1 and T2 was 1.98 x 10(-3) mM. There is no statistically significant difference in T2 and K2 at different repetition times. CONCLUSIONS: This work demonstrates that a single measurement of relaxation times after contrast-enhanced magnetic resonance imaging could be used to determine the Gd-DTPA concentration in CSF. It may thus be feasible, using this technique, to measure intersubject and intraregional variability in the quantity of Gd-DTPA transferred across the blood-brain barrier after intravenous injection of contrast agent.

Blood-Brain Barrier↗
PubMed1985

Time course of polynucleosome relaxation and ADP-ribosylation. Correlation between relaxation and histone H1 hyper-ADP-ribosylation.

Isolated rat pancreatic polynucleosomes were poly(ADP-ribosylated) with purified calf thymus poly(ADP-ribose) polymerase. A time course study was performed using an NAD concentration of 200 microM and changes in nucleosomal structure were investigated by means of electron microscopy visualization and sedimentation velocity determinations. In parallel, analyses of histone H1 poly(ADP-ribosylation) and determinations of DNA polymerase alpha activity on ADP-ribosylated polynucleosomes were done at different time intervals. A direct kinetic correlation between ADP-ribose incorporation, polynucleosome relaxation amd histone H1 hyper-ADP-ribosylation was established. In addition, DNA polymerase alpha activity was highly stimulated on ADP-ribosylated polynucleosomes as compared to control ones, suggesting increased accessibility of DNA to enzymatic action. Because of the strong evidence implicating histone H1 in the maintenance of higher-ordered chromatin structures, the present study may provide a basis for the interpretation of the involvement of the histone H1 ADP-ribosylation reaction in DNA rearrangements during DNA repair, replication or gene expression.

Adenosine Diphosphate Ribose↗
PubMedDate not supplied

Uterine relaxant effect of zolpidem: a comparison with other smooth muscle relaxants.

Zolpidem is an imidazopyridine sedative-hypnotic which interacts with central benzodiazepine-receptors. To examine its effects on uterine smooth muscle we have compared with those obtained by diltiazem, papaverine and diazepam on different experimental models. The IC50 values obtained indicate similar behaviour of zolpidem and diazepam. They showed more active against the spontaneous contractions and those induced by KCl (60 mM) or by CaCl2 (0.01-10 mM) in Ca(2+)-free depolarizing medium than against acetylcholine (0.1 mM)-induced contractions. Both of them also showed more effectiveness against the tonic component of the acetylcholine-evoked contraction than against the phasic one. All the drugs tested were less powerful against contractions induced by oxytocin than against those induced by other agonists. This observation let us speculate that the mechanism of action of zolpidem may be related to an action on Ca2+ influx through voltage-dependent Ca2+ channels due to an interaction with low affinity receptor located at the plasmalemma as has been suggested for diazepam.

Acetylcholine↗