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Effects of the D2 receptor agonist bromocriptine on sleep bruxism: report of two single-patient clinical trials.

An altered dopamine receptor status has been associated with sleep bruxism. Evidence from a functional neuro-imaging study has implicated an abnormal side imbalance in striatal D2 receptor expression in its pathophysiology. To assess the significance of this finding, we studied the effects of short-term administration of the preferential dopamine D2 receptor agonist bromocriptine on sleep bruxism in a double-blind, placebo-controlled polysomnographic and neuro-imaging study with a single crossover design. Six otherwise healthy and drug-free patients with sleep bruxism were entered into the trial. One of the patients dropped out due to an intercurrent illness, while three others were discontinued from the study due to severe adverse reactions to bromocriptine. Because of the high frequency and intensity of the side-effects, the trial was interrupted. Two patients, however, completed the trial without any adverse reactions. Their outcome measures are presented as single-patient clinical trials. Following a two-week administration of bromocriptine, both patients showed a decrease in the number of bruxism episodes per hour of sleep of about 20% to 30% with respect to the placebo. WHile no significant differences between both conditions (i.e., placebo and bromocriptine) were found for the number of bruxism bursts per episode, significantly lower root-mean-squared EMG levels per bruxism burst occurred during bromocriptine use. In association with this polysomnographically established attenuation of sleep bruxism, bromocriptine afforded a decreased normal side distribution of striatal D2 receptor binding, as was evidenced by single-photon-emission computed tomography using the radioactive D2 receptor antagonist iodine-123-iodobenzamide. This study supports previous suggestions that the central dopaminergic system may be involved in the modulation of sleep bruxism. To see if the present findings apply across a population, investigators should use a peripheral D-2 antagonist to prevent side-effects.

Adult↗

[Selection of therapy with nitrates in patients with stable effort angina: results of comparative study of common isosorbide dinitrate and long acting preparation of isosorbide-5-mononitrate].

AIM: To assess efficacy and tolerability of a novel drug form of isosorbide-5-mononitrate in patients with ischemic heart disease and stable effort angina as compared with common isosorbide dinitrate pills. MATERIAL AND METHODS: Patients with stable class II-III effort angina (n=30) were included into a randomized crossover study in which they received isosorbide dinitrate (nitrosorbide, 10-20 mg t.i.d.) and long acting isosorbide-5-mononitrate (ephox-long, 50-100 mg o.d.) for 3 weeks each. Efficacy of treatment was assessed by clinical data and treadmill exercise tests. Questionnaires were used for registration of frequency and intensity of attacks of headache. RESULTS: The use of both isosorbide dinitrate and 5-mononitrate was associated with significant improvements of exercise tolerance however effect of mononitrate lasted longer. Nitroglycerine requirement diminished during first week of use of both drugs and remained on this level by the end of 3-rd week of treatment with mononitrate but substantially rose by the end of treatment with dinitrate. Number of attacks of headache increased during first week of treatment with both drugs, became even higher by the end of use of dinitrate and decreased by the end of use of mononitrate. CONCLUSION: Long acting form of isosorbide-5-mononitrate ephox-long taken once daily provides sufficient antianginal effect throughout a day and is better tolerated than nitrosorbide preparation of isosorbide dinitrate with moderately prolonged activity.

Aged↗

Pergolide restores sleep maintenance but impairs sleep EEG synchronization in patients with restless legs syndrome.

BACKGROUND: The treatment with the long-acting dopamine D1/D2 receptor agonist pergolide has been proven as very effective in lowering the frequency of periodic leg movements (PLM) in patients with restless legs syndrome (RLS). To further investigate the influence of this potent dopaminergic drug on the microstructure of rapid eye movement (REM) and non-REM sleep EEG we established a quantitative analysis of the EEG data. METHODS: The study group consisted of 15 patients with primary RLS (mean age 57.1+/-10.1 years) who were a subgroup of patients within a double-blind randomized crossover treatment study with pergolide versus placebo. The polysomnographic recordings were analyzed visually and submitted to a quantitative EEG analysis (fast Fourier transformation). RESULTS: The pergolide treatment induced a significant reduction of the spectral power in the delta range (0.78-3.9 Hz; P<0.05; t-test) during SWS, as well as a significant reduction of PLMs. In addition, we observed a decrease in the sigma EEG activity (12.1-14.8 Hz; P<0.03) during non-REM sleep and stage 2 sleep. The visual sleep scoring revealed a significant increase in stage 2 sleep (P<0.005), whereas wakefulness was markedly diminished (P<0.001). The REM sleep parameters including the EEG power spectrum remained unchanged. CONCLUSIONS: The treatment with pergolide markedly improved the sleep quality in RLS patients but did not restore SWS including the spectral power in the lower frequencies. Our results suggest that the dopamine agonist pergolide interferes with the subcortical mechanisms regulating the process of EEG synchronization during non-REM sleep.

Clinical Trial↗

Acoustic and perceptual correlates of the non-nasal--nasal distinction for vowels.

For each of five vowels [i e a o u] following [t], a continuum from non-nasal to nasal was synthesized. Nasalization was introduced by inserting a pole-zero pair in the vicinity of the first formant in an all-pole transfer function. The frequencies and spacing of the pole and zero were systematically varied to change the degree of nasalization. The selection of stimulus parameters was determined from acoustic theory and the results of pilot experiments. The stimuli were presented for identification and discrimination to listeners whose language included a non-nasal--nasal vowel opposition (Gujarati, Hindi, and Bengali) and to American listeners. There were no significant differences between language groups in the 50% crossover points of the identification functions. Some vowels were more influenced by range and context effects than were others. The language groups showed some differences in the shape of the discrimination functions for some vowels. On the basis of the results, it is postulated that (1) there is a basic acoustic property of nasality, independent of the vowel, to which the auditory system responds in a distinctive way regardless of language background; and (2) there are one or more additional acoustic properties that may be used to various degrees in different languages to enhance the contrast between a nasal vowel and its non-nasal congener. A proposed candidate for the basic acoustic property is a measure of the degree of prominence of the spectral peak in the vicinity of the first formant. Additional secondary properties include shifts in the center of gravity of the low-frequency spectral prominence, leading to a change in perceived vowel height, and changes in overall spectral balance.

Humans↗

Mass effect on the equienergetic high-spin/low-spin states of spin-crossover in 4,4'-bipyridine-bridged iron(II) polymeric compounds: synthesis, structure, and magnetic, Mössbauer, and theoretical studies.

The suitability of the system [Fe(4,4'-bipy)(H(2)O)(2)(NCX)(2)].(4,4'-bipy), where 4,4'-bipy stands for 4,4'-bipyridine and X = S (1) and Se (2), as a precursor for the synthesis of new polymeric spin-crossover compounds has been studied. The reaction of 1 or 2 with bt (2,2'-bithiazoline) afforded the polymeric compounds of formula [Fe(4,4'-bipy)(bt)(NCX)(2)] (X = S (3), Se (4)). Compounds 3 and 4 are isostructural, but only the crystal structure of 3 has been fully determined. It crystallizes in the orthorhombic system, Fdd2 space group, Z = 24, with a = 38.962(8) A, b = 11.545(2) A, c = 30.889(6) A, V = 13895(5) A(3). The structure consists of linear chains constituted by trans-4,4'-bipy linked iron(II) ions; two cis equatorial positions are occupied by two pseudohalide ligands, and the remaining positions are filled by the bidentate bt ligand. Investigation of their magnetic properties and Mössbauer spectra has revealed the occurrence of a low-spin (LS) <--> high-spin (HS) conversion involving 12% (3, S) and 20% (4, Se) of the Fe(II) ions. The thermal variation of the HS fraction is gradual with onset temperatures as low as 60 K. A theoretical approach based on the Ising-like model, completed with molecular vibrations, through harmonic oscillators, fits the data successfully, leading to an energy gap of 65 cm(-1) (3) and 86 cm(-1) (4) between the lowest LS and HS levels, and an average vibration frequency ohgrmacr;(LS) of 382 cm(-1) (3) and 365 cm(-1) (4) in the LS state. The ca. 1.05 omega(LS(3))/omega(LS(4)) ratio is close to the ca. 1.09 Se/S molar mass ratio. The simple electrovibrational Ising-like model permits us to explain, for the first time, a mass effect through the molecular vibrations in a spin-crossover complex that is in the unusual situation of equienergy among the HS and LS states.

Journal Article↗

Rheological and cohesive properties of hyaluronic acid.

Hyaluronic acid (HA) is a naturally occurring polysaccharide with unique biomedical applications. We have studied the cohesive and rheological properties of HA of three molecular weights (0.35 x 10(6) -1.80 x 10(6) Da) and found that the cohesive nature of HA was highly dependent on molecular weight and solution concentration. To a first approximation, the cohesive nature of HA in solution correlates with concentration, independent of molecular weight. Several rheological parameters correlated with molecular weight: zero shear viscosity, complex viscosity, and the complex viscosity at the crossover point. The cohesive properties of the HA solutions, measured by dynamic aspiration (Poyer et al, J Cataract Refract Surg 1998;24:1130-1135), were found to decrease as the zero shear viscosity increases. The cohesive properties of HA polymer in solution were found to correlate with the high frequency complex viscosity and high frequency loss modulus independent of molecular weight.

Biocompatible Materials↗

Sotalol versus class I and II antiarrhythmic agents.

In two separate, double-blind, multicenter antiarrhythmic studies, sotalol was compared with propranolol or quinidine using placebo for baseline and/or washout periods. The comparison with quinidine was a crossover study. To be enrolled in these studies, patients were required to have a premature ventricular contraction (PVC) rate of at least 30/hr on a baseline 24-hour ambulatory ECG. At doses calculated to produce equivalent degrees of beta blockade, sotalol was more effective than propranolol in reducing the frequency of PVCs, and the two drugs produced similar reductions in ventricular tachycardia (VT) events. The side effects for sotalol and propranolol were mainly due to beta blockade, and the incidence of side effects with the two drugs was similar. Sotalol was comparable with quinidine in reducing PVCs and VT events. The side effects on sotalol were primarily related to beta-adrenergic blockade, while those on quinidine were predominantly gastrointestinal or neurologic in nature.

Arrhythmias, Cardiac↗

Locations of crossover breakpoints within the CMT1A-REP repeat in Japanese patients with CMT1A and HNPP.

The crossover breakpoints for Charcot-Marie-Tooth disease type 1A (CMT1A) and hereditary neuropathy with liability to pressure palsies (HNPP) are located in the CMT1A-REP repeat flanking a 1.5-Mb region of chromosome 17p11.2-12. The precise locations of the breakpoints are heterogeneous, and we analyzed the relative frequency distribution of breakpoints in 33 unrelated Japanese CMT1A and 3 unrelated HNPP families. The CMT1A-REP repeat region was divided into five regions, A, B, C, D and E, based on restriction site differences between the proximal and distal CMT1A-REP repeats. The frequency distribution of breakpoints within the CMT1A-REP repeat in the Japanese patients was 3% in region A, .78% in B/C and 19% in D, which is similar to that in Caucasian patients. This result also indicates that an 8-kb region defined by region B/C is a recombinational hotspot within the CMT1A-REP repeat in Japanese patients.

Asian People↗

Cancer incidence patterns among adolescents and young adults in the United States.

OBJECTIVE: The purpose of this study was to examine age-specific cancer incidence patterns among adolescents and young adults (ages 15--49). METHOD: Cancer incidence data for 1995--1999 from 22 population-based central cancer registries, covering about 47% of the US population, were used. Relative frequencies and average annual age-specific incidence rates per 100,000 person-year were computed for the five-year age groups from age 15--19 years through 45--49 years. Tests of significance for comparison were at a level of p<0.05. RESULTS: The age at crossover from a predominance of non-epithelial cancers to a predominance of epithelial cancers during adolescence and young adulthood varied by gender and race. Epithelial cancer became the predominant type of tumor after age 40 years among males while it was the predominant type after age 25 years among females. There was also a shift in the top five cancer types with increasing age, which varied by race and gender. Epithelial cancers of the thyroid, breast, ovary, and cervix uteri started to increase sharply among young women in their 20s while among males epithelial cancers rarely occurred until the early 30s (ages 30--34). Cancers of the female breast, colon and rectum, and lung began to occur at an earlier age and increased more sharply among blacks than among whites. However, the incidence rates of epithelial thyroid and ovarian cancers rose more quickly among whites than blacks. Non-Hodgkin lymphoma and soft tissue sarcoma (excluded Kaposi's sarcoma) increased with age among both whites and blacks but the rates were significantly higher among blacks than among whites. Both Kaposi's sarcoma and testicular cancer incidence increased with age and peaked in the early 30s (ages 30--34). The former was significantly higher among blacks than whites while the latter was significantly higher among whites than blacks. Cervical cancer incidence leveled off when white women reached their 30s, but for black women the rate continued to rise with advancing age. Cutaneous melanoma rates were significantly higher among females than among males between the ages of 15 and 39. Conclusion Cancer incidence patterns among adolescents and young adults are distinctive. Specific cancer prevention and control strategies should be targeted accordingly and tailored to their specific needs.

Adolescent↗

Discordance between effects of anti-ischemic therapy on ambulatory ischemia, exercise performance and anginal symptoms in patients with stable angina pectoris. The Angina and Silent Ischemia Study Group (ASIS).

OBJECTIVES: We sought to define the extent to which the therapeutic efficacy of three single-drug regimens on ambulatory ischemia paralleled efficacy on other clinical manifestations of ischemia, specifically exercise test performance and anginal symptoms. BACKGROUND: Some studies have shown that the presence and severity of ambulatory ischemia are predictive of anginal symptoms and exercise test performance, whereas other studies have not. Less is known about effects of antianginal treatment and whether response to therapy for one clinical manifestation reflects therapeutic responses for other clinical manifestations. METHODS: We studied 50 patients in the Angina and Silent Ischemia Study who had documented coronary disease, an exercise test positive for ischemia, the presence of ambulatory and asymptomatic ischemia on ambulatory electrocardiographic (ECG) Holter monitoring and stable anginal symptoms. Patients received maximally tolerated doses of sustained release propranolol (mean 293 mg/day), sustained release diltiazem (mean 350 mg/day), nifedipine (mean 79 mg/day) and placebo, each for 2-week periods in a double-blind, crossover fashion. Patients' responses to treatment were assessed by 48-h ambulatory ECG monitoring, exercise test (standard Bruce protocol) and diaries of angina. Levels of efficacy for each agent and for each clinical measure were compared using Spearman correlation analysis. RESULTS: With placebo there was no correlation among the frequency of ischemic episodes by ambulatory ECG monitoring, exercise time to 1.0-mm ST segment depression or frequency of anginal episodes. Furthermore, for a given patient the efficacy of each active medication in reducing ambulatory ischemia was not correlated with response in anginal symptoms or exercise test performance (r = -0.21 to 0.24, p = NS). Within each of these clinical measures, efficacy of one drug was more strongly correlated with efficacy of another drug (r = 0.64 to 0.81 for ambulatory ischemia, 0.48 to 0.56 for exercise test performance and 0.16 to 0.54 for anginal symptoms). CONCLUSIONS: Different measures of ischemia, specifically ambulatory ischemia assessed by ambulatory ECG monitoring, exercise performance on exercise test and anginal symptoms, are independent. Efficacy for each clinical end point must be assessed separately when considering response to drug treatment.

Aged↗

Randomised double-blind placebo-controlled trial of feverfew in migraine prevention.

The use of feverfew (Tanacetum parthenium) for migraine prophylaxis was assessed in a randomised, double-blind, placebo-controlled crossover study. After a one-month single-blind placebo run-in, 72 volunteers were randomly allocated to receive either one capsule of dried feverfew leaves a day or matching placebo for four months and then transferred to the other treatment limb for a further four months. Frequency and severity of attacks were determined from diary cards which were issued every two months; efficacy of each treatment was also assessed by visual analogue scores. 60 patients completed the study and full information was available in 59. Treatment with feverfew was associated with a reduction in the mean number and severity of attacks in each two-month period, and in the degree of vomiting; duration of individual attacks was unaltered. Visual analogue scores also indicated a significant improvement with feverfew. There were no serious side-effects.

Adult↗

Clustering of meiotic double-strand breaks on yeast chromosome III.

In the yeast Saccharomyces cerevisiae, meiotic recombination is initiated by transient DNA double-strand breaks (DSBs) that are repaired by interaction of the broken chromosome with its homologue. To identify a large number of DSB sites and gain insight into the control of DSB formation at both the local and the whole chromosomal levels, we have determined at high resolution the distribution of meiotic DSBs along the 340 kb of chromosome III. We have found 76 DSB regions, mostly located in intergenic promoter-containing intervals. The frequency of DSBs varies at least 50-fold from one region to another. The global distribution of DSB regions along chromosome III is nonrandom, defining large (39-105 kb) chromosomal domains, both hot and cold. The distribution of these localized DSBs indicates that they are likely to initiate most crossovers along chromosome III, but some discrepancies remain to be explained.

Chromosome Mapping↗

Analysis of non-crossover bivalents in pachytene cells from 10 normal men.

BACKGROUND: Bivalents with no recombination foci (possible achiasmates) are unable to orient properly on the metaphase plate or to segregate chromosomes to daughter cells. Non-crossover bivalents are known to cause meiotic arrest in various organisms. METHODS: Individual non-crossover bivalents were identified in 886 pachytene cells (19 492 bivalents) from testicular biopsies of 10 normal men. Fluorescence staining combined with centromere-specific multicolour fluorescence in situ hybridization (cenM-FISH) was used to identify mismatch repair gene mutation of human mutL homologue 1 (MLH1) recombination foci along each bivalent synaptonemal complex (SC). RESULTS: A total of 60 autosomal non-crossovers (SCs without an MLH1 focus) were found, and of these, chromosomes 21 (2.1%) and 22 (1.7%) had a significantly higher proportion than chromosomes 11, 12, 19 (each 0.1%), 13 (0.2%), 14 (0.6%), 16 (0.5%) and 15, 17, 18, 20 (each 0.3%) (P < 0.05). Sex chromosome univalents had a frequency of 27%, higher than that observed in any autosomal bivalent (P < 0.0001). CONCLUSIONS: These results suggest that G-group chromosomes and sex chromosomes are most susceptible to having no recombination foci and thus would be more susceptible to non-disjunction during spermatogenesis. This is consistent with previous observations from sperm karyotyping and FISH analysis, which demonstrate that chromosomes 21 and 22 and the sex chromosomes have a significantly increased frequency of aneuploidy compared with other autosomes.

Aged↗

Human immunodeficiency virus type 1 genetic recombination is more frequent than that of Moloney murine leukemia virus despite similar template switching rates.

Retroviral recombinants result from template switching between copackaged viral genomes. Here, marker reassortment between coexpressed vectors was measured during single replication cycles, and human immunodeficiency virus type 1 (HIV-1) recombination was observed six- to sevenfold more frequently than murine leukemia virus (MLV) recombination. Template switching was also assayed by using transduction-type vectors in which donor and acceptor template regions were joined covalently. In this situation, where RNA copackaging could not vary, MLV and HIV-1 template switching rates were indistinguishable. These findings argue that MLV's lower intermolecular recombination frequency does not reflect enzymological differences. Instead, these data suggest that recombination rates differ because coexpressed MLV RNAs are less accessible to the recombination machinery than are coexpressed HIV RNAs. This hypothesis provides a plausible explanation for why most gammaretrovirus recombinants, although relatively rare, display evidence of multiple nonselected crossovers. By implying that recombinogenic template switching occurs roughly four times on average during the synthesis of every MLV or HIV-1 DNA, these results suggest that virtually all products of retroviral replication are biochemical recombinants.

3T3 Cells↗

Administration of testosterone increases functional connectivity in a cortico-cortical depression circuit.

Increasing evidence suggests that the steroid hormone testosterone (T) enhances libido and decreases depression. Even a single administration of T (0.5 mg sublingually) in healthy young women is sufficient to enhance physiological sexual responsiveness. Such physiological evidence is not yet available for the link between T and depression. Recent research has revealed that lowered functional connectivity in a specific cortico-cortical pathway may be a sensitive physiological index for depression. This pathway, comprised of the left prefrontal and right parietal cortex, has been named a cortical depression circuit. In the present study, a single dose of T was administered to healthy young women to investigate the effects on the functional connectivity in this cortico-cortical depression circuit. It was hypothesized that administration of T would lead to an increase of functional connectivity. In a double-blind placebo-controlled, crossover design, fourteen healthy females received (sublingually) a single dose of 0.5 mg T or placebo in a randomly assigned fashion. Three hours after drug administration the functional coupling between the left prefrontal and right parietal cortex was established by measuring the interhemispheric electroencephalogram (EEG) coherence for the different frequency bands. Compared to placebo, T administration significantly increased the functional connectivity in the sigma (1-3 Hz) frequency range between the left prefrontal and right parietal cortex. Reductions in interhemispheric coherence in the sigma frequency range have been observed in clinically depressed patients. Thus the present findings may provide a first insight into the neurobiological mechanism by which T decreases depression. The fact that only a single dose of T was able to induce the effect in healthy female subjects suggests that the mechanism is highly sensitive. A feasible application of T treatment in the struggle against depression is discussed.

Adult↗

The bioequivalence of nizatidine (Axid) in two extemporaneously and one commercially prepared oral liquid formulations compared with capsule.

Nizatidine (Axid) is an H2-receptor antagonist used for the treatment of acid-related gastrointestinal disorders. Given the frequency of these conditions in children and the potential for pediatric use of nizatidine, an oral liquid dosage formulation would provide an alternative treatment option for patients unable to swallow solid oral dosage forms. This study was designed as an open-label, single-dose, four-way crossover trial to investigate the bioequivalence of 150 mg nizatidine administered in three oral liquid formulations (a commercially prepared oral syrup, an extemporaneous solution in apple juice, and an extemporaneous suspension in infant formula) relative to the marketed capsule formulation. Twenty-four adult subjects (ages 31.2 +/- 7.5 years; weight 71.1 +/- 11.8 kg) were enrolled, and blood samples for determination of plasma nizatidine concentrations were collected prior to drug administration and at 19 discrete intervals over a 24-hour postdose interval. Nizatidine was quantitated from plasma using a validated HPLC-MS assay, and a noncompartmental approach was used to describe nizatidine biodisposition in all subjects. Significant treatment effects were observed for log-normalized Cmax, AUC0-n, and AUC0-infinity (p < 0.001). Further evaluation revealed that nizatidine prepared in apple juice was markedly less bioavailable than the reference capsule, with 90% confidence intervals (CIs) of 0.518-0.626, 0.682-0.751, and 0.696-0.763 for Cmax, AUC0-n, and AUC0-infinity, respectively. The remaining two oral formulations demonstrated 90% CI within the guidelines established by the Food and Drug Administration (e.g., 0.80-1.25). Thus, nizatidine in infant formula and the commercially prepared oral syrup can be considered bioequivalent to the reference capsule.

Adult↗

Effect of melatonin dosage on sleep disorder in tuberous sclerosis complex.

We report a randomized, double-blind, controlled, crossover trial investigating the response to oral melatonin using two dose regimens in patients with sleep disorders associated with tuberous sclerosis complex. Eight outpatients with tuberous sclerosis complex and sleep disorder received either 5 or 10 mg of melatonin. Sleep latency, total sleep time, number of awakenings, and seizure frequency were recorded in sleep and seizure diaries. No evidence of a dose effect between 5 and 10 mg was seen with respect to any outcome measure. (The 5 mg results are given first: sleep latency, 86 and 76 minutes; total sleep time, 8 hours, 57 minutes and 9 hours, 4 minutes; and sleep fragmentation, 0.8 and 1.0). This study might have missed a small beneficial effect of 10 mg melatonin. We propose that an initial trial of 5 mg melatonin is worth considering in patients with tuberous sclerosis complex and sleep disorder.

Administration, Oral↗

Treatment of chronic diarrhoea: loperamide versus ispaghula husk and calcium.

Twenty-five patients with chronic diarrhoea were included in an open, randomized crossover trial comparing the effect of loperamide with ispaghula and calcium. Nineteen patients completed both treatments. Before treatment the median number of daily stools was 7 (range, 4-13), stool consistency was loose in all, and urgency was present in 16 out of 19 patients. Both treatments halved stool frequency, but with regard to urgency and stool consistency ispaghula and calcium was significantly better. A combination of ispaghula and calcium seems to be a cheap and effective alternative to conventional treatment of chronic diarrhoea. Moreover, side effects were minimized.

Adult↗