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PubMed1975

Cromolyn sodium in the treatment of children with severe, perennial asthma.

Cromolyn sodium is a recently introduced drug used in the prophylactic treatment of severe, perennial, bronchial asthma, particularly in the pediatric age group. In a multicenter trial, 276 chronic asthmatic patients of eight pediatric allergists entered a randomized, double-blind, placebo-controlled, crossover study lasting 12 weeks. Test compounds of cromolyn sodium or placebo were inhaled four times a day, and daily scores were kept of symptom severity as well as frequency of use of other medications. Patients had statistically significant lower average daily symptom scores when treated with cromolyn sodium as compared to treatment with placebo. A strong subjective preference for cromolyn sodium was expressed by 60% of those completing the trial, versus 9% for placebo. The patients' need for other symptomatic medications also dropped significantly during the cromolyn treatment period.

Adolescent↗
PubMed2004

The cohesion protein ORD is required for homologue bias during meiotic recombination.

During meiosis, sister chromatid cohesion is required for normal levels of homologous recombination, although how cohesion regulates exchange is not understood. Null mutations in orientation disruptor (ord) ablate arm and centromeric cohesion during Drosophila meiosis and severely reduce homologous crossovers in mutant oocytes. We show that ORD protein localizes along oocyte chromosomes during the stages in which recombination occurs. Although synaptonemal complex (SC) components initially associate with synapsed homologues in ord mutants, their localization is severely disrupted during pachytene progression, and normal tripartite SC is not visible by electron microscopy. In ord germaria, meiotic double strand breaks appear and disappear with frequency and timing indistinguishable from wild type. However, Ring chromosome recovery is dramatically reduced in ord oocytes compared with wild type, which is consistent with the model that defects in meiotic cohesion remove the constraints that normally limit recombination between sisters. We conclude that ORD activity suppresses sister chromatid exchange and stimulates inter-homologue crossovers, thereby promoting homologue bias during meiotic recombination in Drosophila.

Animals↗
PubMed1999

Classical-nonclassical crossover behavior of critical and noncritical liquid binary solutions in a strong electric field.

A nitrobenzene-dodecane binary mixture has been studied with the use of the nonlinear dielectric effect for one critical and two noncritical concentrations in a series of frequencies (f(m)) in a weak measuring electric field. It has been found that for the temperature region where 1/f(m)>tau (tau, the lifetime of fluctuations), the critical exponent psi=gamma-2beta approximately equal to 0.59 and consequently exponents gamma (susceptibility) and beta (order parameter) exhibit nonclassical values. Close to the phase-transition temperature where 1/f(m) 0.5. For the critical concentration psi approximately equal to 0.4, this may be the consequence of the semiclassical behavior with gamma approximately equal to 1 and beta approximately equal to 0.325.

Journal Article↗
PubMed1999

Reproducible fentanyl doses delivered intermittently at different time intervals from an electrotransport system.

The electrotransport transdermal fentanyl system (ET [fentanyl]), uses a small electrical current to enhance delivery of fentanyl to systemic circulation. Intermittent doses can be administered by periodic application of the current. The purpose of this study was to compare the effects of the frequency of intermittent drug delivery by ET (fentanyl) and compare the drug delivery to systemic circulation by ET (fentanyl) with intravenous administration. The topical safety was also determined for the ET (fentanyl) system. Nine adult male volunteers completed this three-treatment, randomized, 24-h, crossover study. ET (fentanyl) treatments with 200 microA direct current applied for 30 min at frequent (hourly) or infrequent (4-hourly) intervals over a 24-h period were compared. Also, the drug delivery to systemic circulation from ET (fentanyl) was compared with intravenous fentanyl 75 microg infused over 30 min every 4 h over a 24-hour period. The mean serum fentanyl concentration achieved with the hourly ET (fentanyl) regimen was higher than that for the 4-hourly ET (fentanyl) regimen as expected from the higher frequency of drug doses. The amount of fentanyl delivered estimated per dose from the ET (fentanyl) system using the iv fentanyl treatment as the reference was similar for the two ET regimens throughout the dosing period. This indicates consistent drug delivery regardless of the frequency of ET dosing. The majority of subjects reported either no, or barely perceptible, erythema 24 h after removal of the system.

Administration, Cutaneous↗
PubMed2005

Effects of botulinum toxin B on refractory detrusor overactivity: a randomized, double-blind, placebo controlled, crossover trial.

PURPOSE: Open, observational studies of intradetrusor injections of botulinum toxin for detrusor overactivity have reported beneficial effects. We tested the efficacy and safety of botulinum toxin B for the treatment of the overactive bladder in a randomized, double-blind, placebo controlled crossover trial. MATERIALS AND METHODS: A total of 20 patients 18 to 80 years old with detrusor overactivity unresponsive to oral antimuscarinic agents participated in the study. They were injected with either placebo (20 ml normal saline) or botulinum toxin B (5,000 IU diluted up to 20 ml) intravesically in a day case setting. After 6 weeks the treatments were crossed over without washout in line with previous findings. The primary outcome was the paired difference in change in average voided volumes. Frequency, incontinence episodes and paired differences in quality of life measured by the King's Health Questionnaire were the secondary outcome measures. RESULTS: The Wilcoxon signed ranks test was used to test the paired difference in change between treatment phases. Little carryover was noted in the second arm placebo and the placebo data from both arms were included in analysis. There were clinically statistically significant paired differences in the change in average voided volume, urinary frequency and episodes of incontinence between active treatment and placebo (average voided volume: 95% CI difference 16, 122; Z2.5; p = 0.012/weekly frequency: 95% CI -21, -1; Z2.1, p=0.033/weekly incontinence: 95% CI -26, -7; Z3.3; p = 0.001). There were similarly significant paired differences in the change in quality of life affecting 5 domains of the King's Health Questionnaire. CONCLUSIONS: This double-blind, placebo controlled, crossover study provides evidence of the efficacy of botulinum toxin B in the treatment of overactive bladder. Autonomic side effects were observed in 4 patients. The short duration of action will presumably limit the use to patients who have experienced tachyphylaxis with botulinum toxin A.

Administration, Intravesical↗
PubMedDate not supplied

Venous irritation related to intravenous administration of phenytoin versus fosphenytoin.

STUDY OBJECTIVE: To compare the frequency, severity, and time course of venous irritation after administration of a single intravenous dose of phenytoin with an equimolar dose of fosphenytoin, a water-soluble phenytoin prodrug. DESIGN: Randomized, double-blind, two-period, crossover study. SETTING: University hospital clinical research unit. PATIENTS: Twelve healthy volunteers within 15% of ideal body weight and with no clinically significant abnormalities on physical examination, medical history, or laboratory assessment. INTERVENTIONS: Volunteers randomly received a 30-minute infusion of phenytoin sodium 250 mg (250 mg/5 ml) or an equimolar dose of fosphenytoin 375 mg (375 mg/5 ml). Subjects returned for the crossover treatment 14-21 days later. MEASUREMENTS AND MAIN RESULTS: Subjects assessed venous irritation (pain, burning, itching), and investigators evaluated phlebitis (erythema, swelling, tenderness), induration, exudation, and cording. Phenytoin was associated with a significantly higher degree of pain at the infusion site in all subjects and a significant degree of phlebitis in eight subjects (p < 0.05); cording occurred in six subjects. The time course of phenytoin-induced phlebitis was bimodal. Erythema and tenderness were prominent at the end of the infusion and again at 24 hours. Cording was first noted between 24 hours and 1 week after infusion. In contrast, fosphenytoin was associated with mild pain in two subjects, one incident of phlebitis, and no erythema or cording. CONCLUSIONS: Fosphenytoin administration resulted in significantly less venous irritation and phlebitis compared with an equimolar dose of phenytoin. The clinical use of this water-soluble phenytoin prodrug should minimize the frequency and severity of infusion-site reactions and should allow convenient, rapid, intravenous administration of drug, undiluted or admixed with intravenous solutions.

Adolescent↗
PubMed2005

Slow transcranial magnetic stimulation can rapidly reduce resistant auditory hallucinations in schizophrenia.

BACKGROUND: Almost a quarter of patients with schizophrenia present with resistant auditory verbal hallucinations (AVH), a phenomenon that may relate to activation of brain areas underlying speech perception. Repetitive transcranial magnetic stimulation (rTMS) at 1 Hz reduces cortical activation, and recent results have shown that 1-Hz left temporoparietal rTMS may reduce AVH. The aim of this study was to replicate recent data and investigate whether low-frequency rTMS with a high total stimulation number delivered in a shorter 5-day block produces similar benefit. METHODS: Ten right-handed schizophrenia patients with resistant AVH received 5 days of active rTMS and 5 days of sham rTMS (2,000 stimulations per day at 90% of motor threshold) over the left temporoparietal cortex in a double-blind crossover design. The two weeks of stimulation were separated by a 1-week washout period. RESULTS: AVH were robustly improved (56%) by 5 days active rTMS, whereas no variation was observed after sham. Seven patients were responders to active treatment, five of whom maintained improvement for at least 2 months. CONCLUSIONS: These data confirm the efficiency of low-frequency rTMS applied to the left temporoparietal cortex, compared with sham stimulation, in reducing resistant AVH. This improvement can be obtained in only 5 days without serious initial adverse events.

Adult↗
PubMed2000

Deficiencies of human complement component C4A and C4B and heterozygosity in length variants of RP-C4-CYP21-TNX (RCCX) modules in caucasians. The load of RCCX genetic diversity on major histocompatibility complex-associated disease.

The complement component C4 genes located in the major histocompatibility complex (MHC) class III region exhibit an unusually complex pattern of variations in gene number, gene size, and nucleotide polymorphism. Duplication or deletion of a C4 gene always concurs with its neighboring genes serine/threonine nuclear protein kinase RP, steroid 21-hydroxylase (CYP21), and tenascin (TNX), which together form a genetic unit termed the RCCX module. A detailed molecular genetic analysis of C4A and C4B and RCCX modular arrangements was correlated with immunochemical studies of C4A and C4B protein polymorphism in 150 normal Caucasians. The results show that bimodular RCCX has a frequency of 69%, whereas monomodular and trimodular RCCX structures account for 17.0 and 14.0%, respectively. Three quarters of C4 genes harbor the endogenous retrovirus HERV-K(C4). Partial deficiencies of C4A and C4B, primarily due to gene deletions and homoexpression of C4A proteins, have a combined frequency of 31.6%. This is probably the most common variation of gene dosage and gene size in human genomes. The seven RCCX physical variants create a great repertoire of haplotypes and diploid combinations, and a heterozygosity frequency of 69.4%. This phenomenon promotes the exchange of genetic information among RCCX constituents that is important in homogenizing the structural and functional diversities of C4A and C4B proteins. However, such length variants may cause unequal, interchromosomal crossovers leading to MHC-associated diseases. An analyses of the RCCX structures in 22 salt-losing, congenital adrenal hyperplasia patients revealed a significant increase in the monomodular structure with a long C4 gene linked to the pseudogene CYP21A, and bimodular structures with two CYP21A, which are likely generated by recombinations between heterozygous RCCX length variants.

Adrenal Hyperplasia, Congenital↗
PubMed1996

Effects of befloxatone, a reversible selective monoamine oxidase-A inhibitor, on psychomotor function and memory in healthy subjects.

Befloxatone is a new reversible and selective monoamine oxidase (MAO-A) inhibitor that has been shown to have antidepressant activity in various animal models. To assess the effects of single oral doses of befloxatone (5, 10, and 20 mg) on psychomotor performance and memory, a randomized, double-blind, five-way, crossover study with both placebo and amitriptyline (50 mg) was carried out in 15 healthy male volunteers. Psychomotor and cognitive functions were evaluated using both objective measures, including Critical Flicker Frequency (CFF), Choice Reaction Time (CRT), Digit Symbol Substitution Test (DSST), and a picture memory test and subjective measures, including Visual Analog Scales (VAS) and Addiction Research Center Inventory (ARCI), before and 2, 4, and 8 hours after administration. Pupil diameter was recorded by videopupillography. Single doses of befloxatone from 5 to 20 mg did not result in any detrimental effects on skilled performance and memory. In contrast, amitriptyline significantly impaired arousal (CFF), speed of reaction (CRT), information processing (DSST) and long-term memory (delayed free recall of pictures) and produced subjective sedation from 2 to 8 hours after administration. At the doses studied amitriptyline induced miosis but befloxatone did not modify pupil diameter. There was no evidence in this study to suggest that befloxatone, at the doses studied, has any sedative or amnesic effects in healthy subjects.

Adult↗
PubMed2001

The placebo response to citric acid-induced cough: pharmacodynamics and gender differences.

Characteristics of the response to placebo in a citric acid-induced cough challenge were investigated as part of a randomized, double-blind crossover trial to assess the antitussive effect of dextromethorphan. Baseline cough responses were established on two occasions in 22 healthy subjects. They received 60 ml placebo antitussive syrup and cough frequency following five inhalations of 10% citric acid over 5 min was measured at regular intervals up to 12 h. Response-time models of varying complexity were used to describe the placebo cough suppression data. The cough response to placebo was also compared to that of the untreated state. The placebo cough response was best characterized by a non-linear increase in cough suppression up to a maximum reduction of 1.6 coughs from baseline at 4-4.5 h, followed by a non-linear return to baseline. The cough response in the untreated state was not different from that of placebo (P=0.99). Females coughed more frequently than males (median number of coughs=10.5 vs. 9.0, respectively P<0.001; Mann-Whitney U test), and adaptation to the cough stimulus was significantly more rapid in females (P<0.025). Accordingly, in trials that use citric acid-induced cough, gender should be considered in study design, particularly in relation to the timing of measurements.

Administration, Inhalation↗
PubMed1987

Effect of digitoxin on cardiac arrhythmias in hemodialysis patients.

Digitoxin is considered a risk factor for ventricular arrhythmias in hemodialysis patients. In a randomized, crossover controlled study, 55 hemodialysis outpatients with sinus rhythm were prospectively investigated in two 48-h periods of electrocardiographic monitoring, one on and one off digitoxin or vice versa. The frequency of ventricular ectopic beats (mean +/- SD) which were found in 31 of 55 patients (56%), was slightly higher on hemodialysis (10 +/- 28 beats/h) than in the following 20 h (5.4 +/- 10 beats/h) and the next day off hemodialysis (3.6 +/- 6.6 beats/h); however, no difference was seen in patients on digitoxin during hemodialysis (10 +/- 29 beats/h), in the following 20 h (4.8 +/- 15 beats/h) and on the next day off hemodialysis (1.2 +/- 6.6 beats/h). The frequency of ventricular bigemini, polymorphous ectopies, couplets, more than 30 ectopies/h, salvos and tachycardias (10 vs 9 patients) on and off digitoxin was about the same (n.s., Fisher test). Supraventricular bigemini, salvos, tachycardias, and atrial fibrillation, however, occurred in significantly fewer patients on digitoxin (3 vs 13) than in those off digitoxin (P = 0.01, Fisher test). It is concluded that digitoxin does not increase the risk of ventricular arrhythmias in hemodialysis patients. Digitoxin, however, may have a beneficial effect on the supraventricular arrhythmias frequently observed in these patients.

Adult↗
PubMed1987

Efficacy of sustained-release verapamil in chronic stable angina pectoris.

The effectiveness of a sustained-release preparation of verapamil (verapamil-SR) was compared with the regular formulation of verapamil and with placebo in 12 patients with chronic stable angina pectoris. All patients completed an 8-week, double-blind, double-crossover, randomized protocol with 2-week treatment periods of verapamil-SR, 240 mg twice daily; regular-formulation verapamil, 120 mg 4 times daily; and 2 placebo therapies. The frequency of weekly anginal episodes was reduced from 7.6 +/- 10.0 with placebo to 3.1 +/- 4.2 after the regular formulation of verapamil (p = 0.09) and from 6.4 +/- 7.6 with placebo to 2.8 +/- 4.8 after verapamil-SR (p = 0.06). Treadmill time increased from 384 +/- 144 seconds during the first placebo phase to 468 +/- 138 seconds after the regular formulation of verapamil (p less than 0.01) and from 354 +/- 102 seconds during the second placebo phase to 462 +/- 138 seconds after verapamil-SR (p less than 0.01). Time to the onset of angina was similarly prolonged by formulations of verapamil. There were no significant adverse effects after 1 year in any patient taking verapamil-SR, 240 mg twice daily. Thus, a twice-a-day verapamil-SR dose regimen is safe and is as effective for treatment of angina of effort as the regular formulation given 4 times a day.

Angina Pectoris↗
PubMed1984

Effects of parenteral administration of estrogen and androgen on plasma hormone levels and hot flushes in the surgical menopause.

In a prospective, double-blind, crossover study, it was found that surgically menopausal women who received an estrogen drug alone and those who were given a combined estrogen-androgen preparation reported a significantly reduced frequency of hot flushes compared to a placebo group (p less than 0.01) coincident with their higher total plasma estrogen levels (p less than 0.01). The administration of testosterone alone, however, was ineffective in alleviating hot flushes, even though these patients had plasma estrogen values that were not different from those of women with intact ovaries. It was proposed that, in women with very low levels of endogenous estrogens, changes in sex hormone-binding globulin (SHBG) concentrations induced by exogenous testosterone may reduce the amount of non-SHBG-bound estrogens, thereby obviating estrogenic effects on hot flushes.

Adult↗
PubMedDate not supplied

Effects of chemical and physical agents on recombination events in cells of the germ line of male and female Drosophila melanogaster.

Genotoxic agents can induce mutations as well as recombination in the genetic material. The fruit fly Drosophila melanogaster was one of the first assay systems to test physical and chemical agents for recombinogenic effects. Such effects can be observed in cells of the germ line as well as in somatic cells. At present information is available on 54 agents, among them 48 chemicals that have been tested in cells of the germ line of males and/or females. Effects on meiotic recombination in female germ cells cannot simply be classified as positive or negative since for a number of agents, depending on the chromosome region studied, recombination frequencies may be increased, unaffected or decreased. The male germ line of D. melanogaster represents a unique situation because meiotic recombination does not occur. Among 25 agents tested in male germ cells 24 did induce male recombination, among them alkylating, intercalating and cross-linking agents, direct-acting ones as well as compounds needing metabolic activation. With several compounds the frequency of induced recombination is highest in the heterochromatic regions near the centromeres. In brood pattern analyses, e.g., after exposure of adult males to ionizing radiation, the first appearance of crossover progeny is indicative of the sampling of exposed spermatocytes. In premeiotic cells of the male and the female germ line mitotic recombination can occur. Upon clonal expansion of the recombinant cells, clusters of identical crossovers can be observed.

Animals↗
PubMed1983

Temporal determinants of spatial sine-wave masking.

A temporal forced-choice procedure was used to measure the contrast threshold for a sinusoidal test grating (spatial frequency - f) superimposed upon a sinusoidal background or masking grating (spatial frequency = 3f). The spatial contrast of the background grating was varied, and threshold measurements were made at each of a number of background contrasts to describe a threshold versus masking contrast (tvc) function. Tvc functions were obtained when the background and test grating contrasts were, independently of each other, held steady (0 Hz) or modulated at 5 Hz. The changes of temporal modulation frequency affected the slopes of the tvc functions. In some cases the tve functions for steady and flickering test gratings crossed one another. The changes of slope suggest, and the crossovers imply, that some steady and flickering patterns are detected by separate visual mechanisms.

Form Perception↗
PubMed1984

Comparative efficacy of nicardipine, a new calcium antagonist, versus nifedipine in stable effort angina.

The relative efficacy of nicardipine and nifedipine was examined in a double-blind placebo-controlled randomized crossover trial. We studied 12 patients with chronic effort angina involving reproducible angina and greater than or equal to 1.5 mm of ST-segment depression on exercise treadmill test performed before and after a 1-week control period of single-blind placebo administration. Subsequently, indistinguishably prepared nicardipine 20 mg, nifedipine 10 mg, or placebo, four times a day, was administered in a randomized double-blind crossover fashion for 3 weeks (total study period 9 weeks). Exercise treadmill test was performed at the end of each 3-week period. Both nicardipine and nifedipine significantly reduced the frequency of anginal attacks and nitroglycerin consumption. Compared with placebo both drugs caused a comparable increase of the duration of exercise, of the time to angina and to the appearance of 1.5 mm ST-segment depression (P less than 0.05 placebo versus nicardipine; P less than 0.01 placebo versus nifedipine respectively). No significant side effects were observed with either drug. We conclude that nicardipine and nifedipine produce similar hemodynamic and clinical effects in patients with stable effort angina.

Aged↗
PubMed1991

Auricular transcutaneous electrical nerve stimulation (TENS) reduces phantom limb pain.

The present paper evaluates the efficacy of low frequency, high intensity auricular transcutaneous electrical nerve stimulation (TENS) for the relief of phantom limb pain. Auricular TENS was compared with a no-stimulation placebo condition using a controlled crossover design in a group of amputees with (1) phantom limb pain (Group PLP), (2) nonpainful phantom limb sensations (Group PLS), and (3) no phantom limb at all (Group No PL). Small, but significant, reductions in the intensity of nonpainful phantom limb sensations were found for Group PLS during the TENS but not the placebo condition. In addition, 10 min after receiving auricular TENS, Group PLP demonstrated a modest, yet statistically significant decrease in pain as measured by the McGill Pain Questionnaire. Ratings of mood, sleepiness, and anxiety remained virtually unchanged across test occasions and sessions, indicating that the decrease in pain was not mediated by emotional factors. Further placebo-controlled trials of auricular TENS in patients with phantom limb pain are recommended in order to evaluate the importance of electrical stimulation parameters such as pulse width and rate, and to establish the duration of pain relief.

Adult↗
PubMed1980

Prevention of isophosphamide-induced urothelial toxicity with 2-mercaptoethane sulphonate sodium (mesnum) in patients with advanced carcinoma.

In 8 patients receiving intravenous isophosphamide 2 g/m2 at 2-week intervals for advanced bronchogenic carcinoma the protective effect of 2-mercaptoethane sulphonate sodium (mesnum) against isophosphamide-induced urothelial toxicity was tested in a single-blind crossover trial. With isophosphamide alone, 7 of the 8 patients developed either haematuria or symptoms of bladder irritation; when mesnum was given in addition, only 1 patient had microhaematuria and frequency, and this was in association with a urinary-tract infection. 5 patients then received fifteen courses of isophosphamide in increasing doses of 4 to 8 g/m2 i.v. with mesnum. In contrast to previous experience with isophosphamide at this high dosage, frank haematuria was never seen, microhaematuria was seen after only three courses, and mild dysuria after only one course. Pharmacokinetic studies showed that mesnum did not interfere with the metabolism of isophosphoramide or its active anti-tumour metabolite, isophosphoramide mustard. Mesnum therefore enhances the therapeutic ratio of isophosphamide and may thereby increase its clinical efficacy.

Acrolein↗