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PubMed1977

Clorazepate: double blind crossover comparison of a single nightly dose with diazepam thrice daily in anxiety.

In a double blind cross-over study in 40 patients with mild to moderate anxiety, clorazepate 15 mg at bedtime was as effective as diazepam on global rating and slightly superior on target symptom assessment. There was a significantly higher incidence and frequency of side effects during diazepam treatment. Occurrence of side effect related to plasma diazepam, and anxiolytic effect related to plasma nordiazepam. These results are discussed in relation to convenience of the single dose regimen and psychomotor performance.

Adolescent↗
PubMed1987

Long-term, placebo-controlled trial of ketotifen in the management of preschool children with asthma.

Forty-seven children with chronic asthma, aged 2 to 6 years, completed a double-blind, placebo-controlled, crossover trial of ketotifen, 1 mg twice daily, in the prophylaxis of asthma. The study period covered two 24-week periods preceded by a 4-week run-in and separated by a 4-week washout. When symptoms, concomitant medication, frequency of acute exacerbations, and parental and physician preferences were analyzed, there were no significant differences between active and placebo treatments. The results suggest that ketotifen has no place in the management of young children with frequent asthma.

Asthma↗
PubMed2001

Effects of norfluoxetine, the major metabolite of fluoxetine, on the cloned neuronal potassium channel Kv3.1.

The effects of fluoxetine and its major metabolite, norfluoxetine, were studied using the patch-clamp technique on the cloned neuronal rat K(+) channel Kv3.1, expressed in Chinese hamster ovary cells. In whole-cell recordings, fluoxetine and norfluoxetine inhibited Kv3.1 currents in a reversible concentration-dependent manner, with an IC(50) value and a Hill coefficient of 13.11+/-0.91 microM and 1.33+/-0.08 for fluoxetine and 0.80+/-0.06 microM and 1.65+/-0.08 for norfluoxetine at +40 mV, respectively. In inside-out patches, norfluoxetine applied to the cytoplasmic surface inhibited Kv3.1 with an IC(50) value of 0.19+/-0.01 microM. The inhibition of Kv3.1 currents by both drugs was characterized by an acceleration in the apparent rate of current decay, without modification of the activation time course and with relatively fewer effects on peak amplitude. The degree of inhibition of Kv3.1 by norfluoxetine was voltage-dependent. The inhibition increased steeply between 0 and +30 mV, which corresponded with the voltage range for channel opening. In the voltage range positive to +30 mV, inhibition displayed a weak voltage dependence, consistent with an electrical distance delta of 0.31+/-0.05. The association (k(+1)) and dissociation (k(-1)) rate constants for norfluoxetine-induced inhibition of Kv3.1 were 21.70+/-3.39 microM(-1) s(-1) and 14.68+/-3.94 s(-1), respectively. The theoretical K(D) value derived by k(-1)/k(+1) yielded 0.68 microM. Norfluoxetine did not affect the ion selectivity of Kv3.1. The reversal potential under control conditions was about -85 mV and was not affected by norfluoxetine. Norfluoxetine slowed the deactivation time course, resulting in a tail crossover phenomenon when the tail currents, recorded in the presence and absence of norfluoxetine, were superimposed. The voltage dependence of steady-state inactivation was not changed by the drug. Norfluoxetine produced use-dependent inhibition of Kv3.1 at a frequency of 1 Hz and slowed the recovery from inactivation. It is concluded that at clinically relevant concentrations, both fluoxetine and its major metabolite norfluoxetine inhibit Kv3.1, and that norfluoxetine directly inhibits Kv3.1 as an open channel blocker.

Algorithms↗
PubMed2006

Larval deformities associated with selenium accumulation in northern pike (Esox lucius) exposed to metal mining effluent.

The objective of this study was to investigate selenium toxicosis in larval northern pike (Esox lucius) originating from reproductively mature pike collected downstream of a uranium milling operation in northern Saskatchewan, Canada. Eggs were obtained from female pike collected from a reference site and three sites representing an exposure gradient (approximately 2, 10, and 15 km downstream of effluent discharge). Embryos were incubated following a two-way (crossover) analysis of variance experimental design that allowed discrimination between effects due to maternal transfer to eggs and effects due to site water exposure in the developing embryos. The major finding of this study was a significant increase in the frequencies of individual deformities (skeletal curvatures, craniofacial deformities, and fin deformities) and edema in fry originating from high and medium exposure site females (mean selenium concentrations of 48.23 and 31.28 microg/g egg dry weight and 38.27 and 16.58 microg/g muscle dry weight, respectively) compared to reference site females. Selenium concentrations resulting in a 20% increase in total deformities above background levels (EC20S) were 33.55 and 21.54 micro/g dry weight in eggs and muscle, respectively. Mathematical conversion of the egg- and muscle-derived relationships to whole body selenium levels resulted in similar EC20S of 15.56 and 17.72 microg/g dry weight, respectively. These relationships between tissue selenium levels and larval deformities suggest that northern pike are within the same range of sensitivity to selenium as the majority of warm water (e.g., centrarchids and cyprinids) and cold water (e.g., salmonids) fish species studied to date.

Animals↗
PubMed1998

Comparative analysis of crossover exchanges and chiasmata in Allium cepa x fistulosum after genomic in situ hybridization (GISH).

Genomic in situ hybridization (GISH) successfully differentiated homoeologous genomes in the inter-specific hybrid Allium cepa x fistulosum, thus allowing the detection of reciprocal crossover events as label exchanges in separating anaphase I chromosomes. Three of the eight chromosome pairs were positively identified by fluorescence in situ hybridization (FISH) to rDNA sequences. There was a general similarity of the GISH-based label exchange frequencies and metaphase I chiasma frequencies, but with a 20% deficit of chiasmata. Reasons for this apparent deficit are discussed. The locations of chiasmata and label exchanges are in broad agreement.

Allium↗
PubMed1999

Roughage revisited: the effect on intestinal function of inert plastic particles of different sizes and shape.

The mechanisms by which dietary fiber exerts its laxative action are not fully understood. Finely grinding wheat bran reduces its effect. Inert plastic particles are equipotent to bran if they consist of flakes or sliced tubing. It is not known whether altering the size or shape of inert particles alters their effect on intestinal function. In a randomized crossover study, 18 volunteers swallowed 24 g/day of plastic as branlike flakes or as small granules for 10-12 days with a two-week washout period between interventions. Whole-gut transit time (WGTT), orocecal transit time (OCTT), defecation frequency, stool form, stool water content, stool pH, and dietary intake were assessed. The plastic flakes caused a 24% (P < 0.001) reduction in WGTT and a 19% (P = 0.002) fall in OCTT. Resultant and appropriate changes in stool form, interdefecatory intervals (IDI), and stool weight were seen. The small granules did not cause any significant change in WGTT or OCTT, although IDI did decrease and stool output and stool form score increased. The stimulant effect of solid particles in the intestinal lumen upon transit time is influenced by the morphology of the particles.

Adult↗
PubMed2001

Lead- and device-related complications in the antiarrhythmics versus implantable defibrillators trial.

BACKGROUND: Implantation of transvenous implantable cardioverter defibrillators (ICDs) by use of a nonthoracotomy approach has become routine therapy for survivors of life-threatening tachyarrhythmias. The purpose of this study was to identify and prospectively characterize the frequency of lead- and ICD-related complications from the Antiarrhythmics versus Implantable Defibrillators (AVID) Trial. METHODS AND RESULTS: Between June 1, 1993, and April 7, 1997, 539 patients received nonthoracotomy ICDs either as initial treatment assignment (477) or as crossover from medical management (62). A total of 62 first complications occurred. The subclavian route of insertion resulted in more complications than the cephalic vein route, 46 of 339 (14%) versus 6 of 135 (4%), P = .005, as did the abdominal versus pectoral generator site, 31 of 238 (13%) versus 17 of 291 (6%), P<.02. Most dislodgements and system infections tended to occur in the 3 months after implantation, whereas lead fractures continued to occur throughout follow-up. Failure to use perioperative antibiotics was a predictor of system infection (P = .001). CONCLUSIONS: These data suggest that cephalic vein access and pectoral generator site may result in fewer complications. The continued occurrence of lead fractures and the need for premature system revision supports the practice of close routine ICD system surveillance.

Anti-Arrhythmia Agents↗
PubMed1995

The safety and efficacy of low-dose tissue plasminogen activator in the treatment of systemic sclerosis.

The safety and efficacy of low-dose (10 mg) recombinant human tissue plasminogen activator (rhtPA: Activase: Genentech) was studied in 14 systemic sclerosis (SSc) patients. The patients were enrolled in a double blind, placebo-controlled crossover trial. Patients who met the inclusion criteria were enrolled in the study, given placebo or rhtPA, and then crossed over at 3 months. Assessment criteria included the Rodnan skin score; a daily patient diary to record side-effects, frequency, and severity of Raynaud's episodes and activity; and pulmonary function tests. Ten mg of rhtPA (Genentech) was administered over a 4 hour period using a myocardial infarction protocol. None of the patients experienced side-effects from the treatment protocol. No differences in the frequency or severity of Raynaud's episodes were noted during the two arms of the study. However, when the mean change of the Rodnan skin score in the placebo arm was compared to the rhtPA arm of the protocol, a significant difference was observed (0.8 vs. -5.4, p < 0.001). Three patients had moderate improvement and seven showed mild improvement. Mild deterioration or no change in study parameters was noted in 4 patients. This study has demonstrated that the administration of low-dose rhtPA is safe and is accompanied by modest improvement in symptoms of a subset of scleroderma patients.

Adult↗
PubMed1978

Effects of central cortical EEG feedback training on incidence of poorly controlled seizures.

This study examined the clinical effects of central cortical EEG feedback training in 8 patients with poorly controlled seizures. After base-line recordings, patients were trained in the laboratory and then initiated on a double or triple crossover design using portable equipment at home, with bimonthly laboratory test sessions. Performance at home was monitored by a strip chart recorder with the portable unit. Training was based on the simultaneous detection of two central cortical (C3--T3) EEG frequency bands (6--9 Hz and either 12--15 or 18--23 Hz), with reward provided for the occurrence of one in the absence of the other. The design consisted of successive 3 month periods of training, with reward contingencies reversed after each period without the subject's knowledge. Seizure incidence records were compared statistically before, during, and after the design. Six of the 8 patients reported significant and sustained seizure reductions, which averaged 74%, following reward for either 12--15 or 18--23 Hz in the absence of 6--9 Hz. Response to positive reward for 12--15 Hz was specific, with seizure rates returning to base line when reinforcement contingencies were reversed. Reduced seizure rates following positive reward for 18--23 Hz were not altered with contingency reversals. A nonspecific interpretation of these effects is rejected in favor of an EEG normalizing hypothesis.

Adolescent↗
PubMed1999

The efficacy of valproate-lamotrigine comedication in refractory complex partial seizures: evidence for a pharmacodynamic interaction.

PURPOSE: To assess the comparative therapeutic value of valproate (VPA), lamotrigine (LTG), and their combination in patients with complex partial seizures resistant to other established antiepileptic drugs (AEDs). METHODS: After a 3-month prospective baseline, 20 adults with refractory complex partial seizures not exposed previously to VPA and LTG were scheduled to receive three consecutive add-on treatments with VPA, LTG, or their combination, according to an open, response-conditional, crossover design. Each period consisted of a 6- to 12-week dose optimization followed by 3-month evaluation at stabilized serum drug levels. Only patients not responding to one phase proceeded to the next. RESULTS: A >50% reduction in seizure frequency was observed in three of 20 patients given VPA and in four of 17 patients given LTG. Of the remaining 13 patients, four became seizure free, and an additional four experienced seizure reductions of 62-78% when VPA and LTG were given in combination. Mild tremor was observed in three patients receiving VPA and in all patients taking the VPA--LTG combination. In patients responding to combination therapy, optimized dosages and peak serum levels of both VPA and LTG were lower than those during separate administration. CONCLUSIONS: A considerable proportion of patients who failed to respond to VPA and LTG separately improved when the two drugs were combined, although serum levels of both agents were lower during combination therapy. Despite methodologic limitations in the nonrandomized treatment sequence, these findings suggest that VPA and LTG exhibit a favorable pharmacodynamic interaction in patients with refractory partial epilepsy. The dosage of both drugs, however, may need to be reduced to minimize the risk of intolerable side effects.

Adult↗
PubMed1997

Progesterone-induced changes in sleep in male subjects.

Progesterone administration induces a reduction of the vigilance state in humans during wakefulness. It has been been suggested that this effect is mediated via neuroactive metabolites that interact with the gamma-aminobutyric, acidA (GABAA) receptor complex. To investigate the effects of progesterone administration on the sleep electroencephalogram (EEG) in humans we made polysomnographic recordings, including sleep stage-specific spectral analysis, and concomitantly measured plasma concentrations of progesterone and its GABA-active metabolites 3 alpha-hydroxy-5 alpha-dihydroprogesterone (allopregnanolone) and 3 alpha-hydroxy-5 beta-dihydroprogesterone (pregnanolone) in nine healthy male subjects in a double-blind placebo-controlled crossover study. Progesterone administration at 9:30 PM induced a significant increase in the amount of non-rapid eye movement (REM) sleep. The EEG spectral power during non-REM sleep showed a significant decrease in the slow wave frequency range (0.4-4.3 Hz), whereas the spectral power in the higher frequency range (> 15 Hz) tended to be elevated. Some of the observed changes in sleep architecture and sleep-EEG power spectra are similar to those induced by agonistic modulators of the GABAA receptor complex and appear to be mediated in part via the conversion of progesterone into its GABA-active metabolites.

Administration, Oral↗
PubMed1989

Effects of single oral doses of bromazepam, buspirone and clobazam on performance tasks and memory.

Three anxiolytic drugs (bromazepam 3 mg, buspirone 10 mg, and clobazam 10 mg p.o.) were evaluated for their effects on memory, psychomotor performance and subjective response in a double-blind, placebo-controlled, crossover study in 20 healthy volunteers. At each session, measurements were made before and 2 and 6 h after drug administration. The psychometric tests used were the images test, digit/symbol substitution test (DSST), choice reaction time (CRT), and critical fusion frequency (CFF). Free recall after 30 s in the 2-hour session was altered for all 3 drugs as compared to placebo (p less than 0.01), but in the 6-hour session only bromazepam showed a significant difference (p less than 0.05). The number of symbols reproduced by subjects during DSST was significantly decreased by bromazepam and buspirone as compared to placebo (p less than 0.05), whereas clobazam showed no differences with placebo. Analysis of variance for all four treatments (the 3 drugs and the placebo) showed no differences at recognition time or for motor response in CRT, except between bromazepam and clobazam after 6 h (p less than 0.05). None of the drugs altered performance during CFF (except bromazepam), and clobazam actually improved performance. All the drugs studied disturbed acquisition phenomena or restitution of memory; however, only bromazepam and buspirone significantly modified performance during DSST and disturbed the recognition and processing of sensory data.

Administration, Oral↗
PubMed1990

Comparative cognitive effects of anticonvulsants.

We investigated the neuropsychological effects of carbamazepine, phenobarbital, and phenytoin in 15 partial complex epilepsy patients treated with each drug for 3 months, using a randomized double-blind, triple crossover design. Neuropsychological evaluation at the end of each treatment period included Digit Span, Selective Reminding Test, Digit Symbol, Finger Tapping, Grooved Pegboard, Choice Reaction Time, P3 evoked potential, and Profile of Mood States. Employing anticonvulsant blood levels and seizure frequencies as covariates, the only significant difference was for Digit Symbol. Performance with phenobarbital was significantly worse than with the other 2 anticonvulsants despite phenobarbital's having had the lowest overall blood levels. Our data show that patients receiving carbamazepine, phenobarbital, and phenytoin have comparable neuropsychological performance on most measures. The results suggest that the differential cognitive effects of anticonvulsants may be subtle.

Adult↗
PubMed1983

The use and safety of Ibuprofen in the hemophiliac.

After demonstrating initial safety of Ibuprofen administered to hemophiliacs, a 16-wk double-blind individual crossover trial was designed to test the safety and, to a more limited extent, the efficacy of 1600 mg of Ibuprofen or placebo given daily to 20 hemophiliacs with hemophiliac arthropathy. The trial was completed with no evidence of increased frequency or severity of hemophiliac bleeding episodes or clinical or laboratory evidence of bleeding secondary to Ibuprofen. There were five treatment failures, none associated with hemorrhage or lack of compliance. A benefit was obtained in reduction of early morning stiffness and pain. Ibuprofen should be considered as a safe and potentially beneficial antiinflammatory agent in the treatment of carefully monitored hemophiliacs eligible for such therapy.

Adolescent↗
PubMed1984

Double-blind multiple-dose crossover study of the antiemetic effect of intramuscular levonantradol compared to prochlorperazine.

Twenty cancer patients who received chemotherapy were entered into a double-blind crossover design antiemetic study comparing 1 mg levonantradol, an investigational synthetic cannabinoid, to 10 mg prochlorperazine. Sixteen patients completed the crossover. For each antiemetic course, four doses of each study medication were given intramuscularly 2 hours before chemotherapy and then 2, 6, and 10 hours after chemotherapy administration. There were no statistical differences in patients' responses to levonantradol and prochlorperazine. The frequency of side effects was greater with levonantradol than with prochlorperazine. The most common side effect of levonantradol were somnolence, dry mouth, dizziness, tachycardia, postural hypotension, and blurred vision, while those for prochlorperazine were somnolence, dry mouth, and tachycardia.

Adolescent↗
PubMed1991

Effects of vector cutting on its recombination with the chromosomal immunoglobulin gene in hybridoma cells.

We have analyzed the effects of linearizing vector DNA on the frequency and pathway of its recombination with the homologous chromosomal gene. The pSV2neo vector bearing a 4.3-kb fragment encoding the mouse immunoglobulin mu heavy chain constant (C mu) region was cut either at sites within the C mu segment or outside C mu and then transferred to hybridoma cells bearing a mutant mu gene. The frequency of recombinant cells producing normal mu was then measured. For most cut sites, whether in regions of homology or of nonhomology, linearization of the transferred DNA enhanced the recombination frequency between the vector and chromosomal mu genes. When the vector was either uncut or cut at SacI in the region of homology, G418-resistant mu m+ recombinants were found to have integrated the vector by a single reciprocal homologous crossover; the enzyme site (SacI) used for cutting was present in the recombinants. By contrast, when the vector had been linearized at PvuI or SfiI in the region of nonhomology, vector integration involved nonhomologous crossovers, either between transferred DNA molecules or between transferred and chromosomal DNA, and the vector cut sites were absent in these recombinants. Some recombinants were found to have an unaltered as well as recombinant mu gene, suggesting that the nonhomologous recombination process might have involved sister chromatids.

Animals↗
PubMed1976

Significance of tartrazine sensitivity in chronic urticaria of unknown etiology.

Of 38 patients with chronic urticaria of unknown etiology who were evaluated for food and drug additive sensitivity, 53% (20/38) had urticaria for 1 yr or more. Total eosinophil counts were not elevated in most patients, and the frequency of atopy was found to be similar to that in a general population. Of these 38 patients, 10 (26%) had a personal history of aspirin intolerance, but elimination of aspirin did not relieve the urticaria. In a double-blind crossover challenge with 0.22 mg of tartrazine and a control, tartrazine sensitivity was found in 8% (3/38) of patients with chronic urticaria and 20% (2/10) of patients with aspirin intolerance.

Adult↗
PubMed1983

Failure of children with asthma to respond to daily aspirin therapy.

Adverse reactions to aspirin in asthmatic patients have been widely described in the past. In contrast to this more frequent complication, several authors have published reports suggesting that aspirin and other nonsteroidal anti-inflammatory drugs can improve asthma. We studied the effect of long-term aspirin administration in children with moderately severe asthma. Ten children who showed no immediate effect of aspirin challenge (either adverse or beneficial) were placed in a 9 wk, double-blind crossover study, receiving aspirin (10 gr twice daily) or placebo for 4 wk, then a 1 wk washout period, followed by aspirin or placebo for 4 wk. There was no difference between aspirin and placebo periods in number of wheezing episodes, frequency of additional bronchodilator or prednisone use, or daily spirometric measurements. Serum thromboxane B2 levels were significantly reduced during aspirin therapy (p less than 0.001), indicating that the patients had complied with the aspirin therapy. Thus long-term administration of aspirin to asthmatics who show no immediate beneficial or adverse response to aspirin challenge appeared not to influence the clinical course of asthma. In addition, inhibition of the platelet prostaglandin cyclooxygenase pathway in these patients did not modify the clinical course of their asthma.

Adolescent↗