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Results for “randomized crossover trial”

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At least 325 records · Page 18Linked to original sources

PubMed1989

Once-daily irrigation of long-term urethral catheters with normal saline. Lack of benefit.

Urinary incontinence is often managed with a long-term urethral catheter after other methods have failed. Such urethral catheterization is associated with polymicrobial bacteriuria, catheter obstruction, fever, bacteremia, urinary tract stones, and death. Periodic catheter irrigation is a common but untested management procedure intended to prevent catheter obstruction, fevers, and/or bacteremia. To evaluate this technique, we performed a randomized crossover trial comparing ten weeks of once-daily normal saline irrigation with ten weeks of no irrigation in 32 long-term catheterized women. The incidence of catheter obstructions and febrile episodes and the prevalence and species of bacteriuria were similar whether examined as completed crossover patients (N = 23) or as partially completed trials (N = 9). Once-daily irrigation with normal saline of long-term urethral catheters is a time-consuming and costly procedure that is unlikely to have an impact on the morbidity associated with such catheters.

Adult↗

PubMed1992

Alzheimer-type dementia and verbal memory performances: influence of selegiline therapy.

In a double blind randomized crossover trial lasting 6 months selegiline, a selective MAO-B inhibitor, was tested against placebo for activity on verbal memory performances in Alzheimer-type dementia (DAT). Verbal memory was assessed with the Rey-Auditory-Verbal Learning Test at the start of treatment, at the time scheduled for crossover (90 days) and at the end of the trial (180 days). The results suggest that selegiline possesses significant activity on some memory parameters, which seems to depend on an improvement both in information processing abilities and in learning strategies at the moment of acquisition.

Alzheimer Disease↗

PubMed1988

[Effect of nedocromil sodium on the hyperreactivity of the bronchial system in young asthmatic patients].

The protective effect of nedocromil sodium on asthmatic children was investigated by exercise provocation test in a placebo-controlled, double-blind, randomized crossover trial. Lung function impairment during exercise was significantly less (p less than 0.05) with nedocromil sodium than with placebo. The maximum impairment of lung function after exercise challenge was significantly less (p less than 0.05) with nedocromil sodium than with placebo. No side-effect were observed.

Adolescent↗

PubMed1991

Sodium depresses arterial baroreceptor reflex function in normotensive humans.

Sodium may contribute to the pathogenesis of hypertension by impairing arterial baroreceptor reflex function. The objectives of this study were to 1) determine whether a high sodium diet depresses arterial baroreceptor reflex function in normotensive humans, and 2) determine whether alterations in baroreceptor reflex function are related to changes in arterial compliance. Seventeen normotensive men, aged 30 +/- 2 years, received 10 and 200 meq sodium per day diets, each for 5 days, in a randomized crossover trial. Carotid baroreceptor reflex function was assessed by measuring the blood pressure response to sequential neck suction (0, -10, -20, and -30 mm Hg) and neck pressure (0, +10, +20, and +30 mm Hg). Forearm vascular resistance was determined by venous occlusion plethysmography. Arterial compliance was evaluated by calculating the quotient of the diastolic blood pressure decay time constant and forearm vascular resistance. Blood pressure averaged 124 +/- 3/62 +/- 2 mm Hg on the low sodium diet and 122 +/- 3/60 +/- 2 mm Hg on the high sodium diet (p = NS). Baroreceptor reflex slopes representing the systolic and diastolic blood pressure responses to changes in neck chamber pressure were steeper in the subjects when randomly assigned to low sodium diet than to high sodium diet. Diastolic blood pressure decay time and forearm arterial compliance were similar during low and high sodium intake. We conclude that short-term exposure to a high sodium diet depresses carotid baroreceptor reflex function in normotensive humans. This observation cannot be attributed to changes in the arterial compliance.

Adult↗

PubMed1992

Use of transcutaneous electrical nerve stimulation for fingertip analgesia: a pilot study.

STUDY OBJECTIVES: To determine if transcutaneous electrical nerve stimulation (TENS) can produce fingertip analgesia. DESIGN: Randomized, crossover trial. PARTICIPANTS: Fifteen healthy volunteers, naive to the technique of TENS. INTERVENTIONS: TENS stimulation was applied to the middle and ring fingers of each subject's hands by means of small carbon electrodes placed over the digital nerves. Patients received one fingertip puncture from a mechanically driven sterile lancet device to each digit corresponding to one of four conditions: sham, one minute of TENS, ten minutes of TENS, and 20 minutes of TENS. The TENS unit was operated in the "burst" mode, with two eight-pulse burst groups per second (pulse width, 225 mu sec; pulse frequency, 80 Hz). The order of the conditions and the finger used for each condition were assigned randomly. The pain of each puncture was rated on a 10-cm visual-analog scale. Data were analyzed using a repeated-measures analysis of variance with Duncan's multiple comparisons procedure. MEASUREMENTS AND RESULTS: Mean visual-analog scale scores decreased sequentially from sham in each experimental condition: one minute of TENS, 24.4% (P < .025); ten minutes of TENS, 28.2% (P < .025); and 20 minutes of TENS, 55.7% (P < 10(-6)). Two patients had total anesthesia of the fingertip (visual-analog scale = 0 cm) in the 20-minute TENS condition. CONCLUSION: TENS significantly reduces the pain of lancet-induced trauma to the fingertip. Further studies are warranted to determine if this technique is useful clinically as an alternative or adjunct to digital nerve block anesthesia for fingertip surgical procedures.

Finger Injuries↗

PubMed1989

Efficacy of charcoal cathartic versus ipecac in reducing serum acetaminophen in a simulated overdose.

The traditional role of gastric emptying as the initial step in the management of the poisoned patient has recently been questioned; immediate activated charcoal administration has been recommended by some. In the setting of acetaminophen overdose, ipecac-induced emesis may interfere with subsequent oral antidotal therapy. Therefore, we conducted a study to compare the efficacy of initial therapy with ipecac with therapy with activated charcoal-cathartic in a simulated acetaminophen overdosage. Ten healthy volunteers participated in a randomized, crossover trial. Subjects ingested 3.0 g acetaminophen, followed by either no intervention, 30 mL syrup of ipecac, or 50 g activated charcoal-sorbitol solution at one hour. Serial acetaminophen levels were determined at intervals over eight hours. Both interventions significantly reduced the area under the curve compared with control (P less than .05). When comparing ipecac with activated charcoal-cathartic, no significant difference was noted among these groups.

Acetaminophen↗

PubMed1996

Prospective randomized study of sulindac versus calcium and calciferol for upper gastrointestinal polyps in familial adenomatous polyposis.

Eighteen patients with familial adenomatous polyposis (FAP) who had previously undergone colectomy but had upper gastrointestinal polyps were studied in a double-blind randomized crossover trial comparing sulindac with calcium and calciferol. Sulindac produced a reduction in the crypt proliferation index in the gastric epithelium of patients but did not significantly affect duodenal mucosa. Calcium with calciferol did not have any effects on crypt proliferation index in patients with FAP.

Adenomatous Polyposis Coli↗

PubMed2006

Clinical experience with tiered atrial therapies and atrial arrhythmia prevention algorithms in a dual chamber cardioverter defibrillator.

INTRODUCTION: The acceptance of atrial arrhythmia features in implantable cardioverter defibrillators (ICDs) will depend on their ability to appropriately discriminate atrial tachyarrhythmias/atrial fibrillation (AT/AF). This study tested the effectiveness of an atrial/ventricular ICD with advanced atrial detection and new algorithms designed to prevent atrial arrhythmias. METHODS AND RESULTS: Ninety-five patients were implanted with a dual chamber ICD (Model 1900, Guidant Corporation, MN, USA) at 25 US centers. Ten patients received a coronary sinus (CS) lead allowing a defibrillation vector for AT/AF cardioversion. Follow-up was 12.2 months. The addition of new atrial features designed for detection, discrimination, and prevention of AT/AF had no adverse effect upon detection of induced ventricular fibrillation (VF) (mean detection time with new features ON was 2.22 seconds vs 2.19 seconds with features OFF). A total of 100% of the induced and spontaneous ventricular and atrial arrhythmias receiving shock therapy were reviewed as appropriate detection. Atrial shock conversion efficacy for spontaneous and induced AT/AF episodes was 83% and 96%, respectively (144 spontaneous, 162 induced episodes). A 3-month randomized crossover trial of atrial preventative pacing features did not result in adverse effects, but there was no clinical efficacy for prevention of AT/AF. CONCLUSION: Enhanced atrial detection and discrimination features combined with tiered atrial therapies did not adversely impact the ability of the ICD (Model 1900) to appropriately detect and treat ventricular tachyarrhythmias.

Aged↗

PubMed1978

Dopaminergic agonist Ro 8-4650 in Parkinson's disease. I. Patients treated with dopa.

An isoquinoline derivative Ro 8-4650 (rac-4-(3,4-dichlorophenyl)-1,2,3,4-tetrahydro-7-methoxy-2-methylisoquinoline hydrochloride) with dopaminergic properties was studied in a randomized crossover trial. The group studied comprised 37 patients with idiopathic parkinsonism and persistent symptoms, despite levodopa treatment. Median Webster rating before allocation was 11.5. The trial drug did not differ significantly from placebo as regards effect and involuntary movements. It led to more frequent minor side effects.

Clinical Trials as Topic↗

PubMed1982

Beta-blocker therapy evaluated by radionuclide angiography: a study in chronic stable angina.

In order to evaluate the negative inotropic effects of sotalol, metoprolol, and propranolol in patients with chronic stable angina pectoris, left ventricular ejection fraction (LVEF) was measured with radionuclide angiography and echocardiography. Fifteen patients entered the study, which was designed as a randomized crossover trial. The patients served as their own control at all times. Surprisingly, LVEF increased when measured by echocardiography in all three treatment periods, and decreased in the propranolol period when measured by radionuclide methods. The changes were not significant. There was no negative inotropic effect registered during any of the three drug treatments.

Adrenergic beta-Antagonists↗

PubMed1995

In vitro and in vivo evaluation of a once-daily controlled-release pseudoephedrine product.

The functionality of a once-daily, osmotic dosage form--gastrointestinal therapeutic system (pseudoephedrine HCl) or GITS (PeHCl)--was studied in vitro and in vivo. The in vitro release profiles were close to identical from pH 1 to 7.5 and between USP apparatus 2 and 7, independent of paddle speeds from 50 to 200 rpm; GITS also released drug at the normal rate in aqueous media after incubation in bile salts or fatty media. Both strengths of GITS (PeHCl)--240 and 120 mg--were then compared with a commercially available pseudoephedrine solution given every 6 hours and a timed-release 12-hour pseudoephedrine capsule given every 12 hours in a randomized 4-way crossover study in 24 healthy men. All four formulations were equivalent in total drug absorbed. Both GITS treatments had AUCinf values equivalent to those of PeHCl solution and capsules, and Cmax values equivalent to PeHCl capsules. Cmax for GITS and capsule treatments were each significantly lower than for solution, but the differences were small (14-17%). A one-to-one correlation was shown between rate of absorption and in vitro release profiles for the GITS products, indicating that drug release from GITS controls absorption. Insensitivity to conditions of in vivo release accounts for the close in vitro/in vivo correlation of release rates. In a second randomized crossover trial (12 men), the effect of a high-fat breakfast on GITS performance was evaluated. Mean pseudoephedrine concentrations in plasma were close to identical with or without the breakfast, and the treatments were bioequivalent.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1987

The effect of an oral leukotriene antagonist L-649,923 on histamine and leukotriene D4-induced bronchoconstriction in normal man.

We have studied the effect of prior treatment with an oral leukotriene (LT) antagonist L-649,923, on histamine and LTD4-induced bronchoconstriction in 12 normal male subjects in a double-blind, placebo-controlled, randomized, crossover trial. L-649,923 had no effect on histamine-induced bronchoconstriction but antagonized LTD4-induced bronchoconstriction, causing a mean shift to the right of the dose-response curves of 3.8-fold. This study demonstrates that LT antagonism is possible and safe in man and that LTD4-inhalation challenge testing can be used to detect LT antagonism.

Adult↗

PubMed2003

Novel antiviral agents: a medicinal plant perspective.

Several hundred plant and herb species that have potential as novel antiviral agents have been studied, with surprisingly little overlap. A wide variety of active phytochemicals, including the flavonoids, terpenoids, lignans, sulphides, polyphenolics, coumarins, saponins, furyl compounds, alkaloids, polyines, thiophenes, proteins and peptides have been identified. Some volatile essential oils of commonly used culinary herbs, spices and herbal teas have also exhibited a high level of antiviral activity. However, given the few classes of compounds investigated, most of the pharmacopoeia of compounds in medicinal plants with antiviral activity is still not known. Several of these phytochemicals have complementary and overlapping mechanisms of action, including antiviral effects by either inhibiting the formation of viral DNA or RNA or inhibiting the activity of viral reproduction. Assay methods to determine antiviral activity include multiple-arm trials, randomized crossover studies, and more compromised designs such as nonrandomized crossovers and pre- and post-treatment analyses. Methods are needed to link antiviral efficacy/potency- and laboratory-based research. Nevertheless, the relative success achieved recently using medicinal plant/herb extracts of various species that are capable of acting therapeutically in various viral infections has raised optimism about the future of phyto-antiviral agents. As this review illustrates, there are innumerable potentially useful medicinal plants and herbs waiting to be evaluated and exploited for therapeutic applications against genetically and functionally diverse viruses families such as Retroviridae, Hepadnaviridae and Herpesviridae

Antiviral Agents↗

PubMedDate not supplied

Effect of ibuprofen on blood pressure control by propranolol and bendrofluazide.

The effect of 1600 mg/day ibuprofen in two groups of patients with hypertension controlled by either propranolol or bendrofluazide was studied in a double-blind, double-placebo, randomized crossover trial. No significant difference in blood pressure was found at the end of the crossover period in either group, suggesting that the routine co-administration of ibuprofen does not attenuate the anti-hypertensive effect of thiazide diuretics or propranolol. Significant weight gain, attributable to fluid retention, had occurred in the bendrofluazide-treatment group by the end of the drug-free washout period. No significant change in mean weight occurred in the crossover stages in either group, although substantial weight gain was noted during ibuprofen treatment in two patients given bendrofluazide and one given propranolol. Biochemical variables were unaffected by ibuprofen throughout the crossover period. This study suggests that ibuprofen may be administered routinely to patients receiving thiazides or propranolol without loss of control of the anti-hypertensive action of these drugs but it is recommended that individuals are monitored for possible weight gain or an increase in diastolic blood pressure.

Aged↗

PubMed1999

Health effects of vegetables and fruit: assessing mechanisms of action in human experimental studies.

Epidemiologic data support the association between high intake of vegetables and fruits and low risk of chronic disease. There are several biologically plausible reasons why consumption of vegetables and fruit might slow or prevent the onset of chronic diseases. Vegetables and fruit are rich sources of a variety of nutrients, including vitamins, trace minerals, and dietary fiber, and many other classes of biologically active compounds. These phytochemicals can have complementary and overlapping mechanisms of action, including modulation of detoxification enzymes, stimulation of the immune system, reduction of platelet aggregation, modulation of cholesterol synthesis and hormone metabolism, reduction of blood pressure, and antioxidant, antibacterial, and antiviral effects. Although these effects have been examined primarily in animal and cell-culture models, experimental dietary studies in humans have also shown the capacity of vegetables and fruit and their constituents to modulate some of these potential disease-preventive mechanisms. The human studies have relied on intermediate endpoints related to disease risk. Design methodologies used include multiple-arm trials, randomized crossover studies, and more compromised designs such as nonrandomized crossovers and pre- and posttreatment analyses. Length of treatment ranged from a single dose to years depending on the mechanism of interest. Stringency of dietary control varied from addition of supplements to a habitual diet to provision of all food for the duration of a treatment. Rigorously conducted experimental dietary studies in humans are an important link between population- and laboratory-based research.

Antioxidants↗

PubMed1985

Estimation of gastric residence time of the Heidelberg capsule in humans: effect of varying food composition.

In animal and human studies, the gastric emptying of large (greater than 1 mm) indigestible solids is due to the activity of the interdigestive migrating myoelectric complex. The gastric residence time (GRT) of an orally administered, nondigestible, pH-sensitive, radiotelemetric device (Heidelberg capsule) was evaluated in three studies in healthy volunteers. In 6 subjects, the GRT of the Heidelberg capsule was compared with the half-emptying time (t1/2) of diethylenetriaminepentaacetic acid labeled with technetium 99m after a 4-ml/kg liquid fatty meal. The mean (+/-SD) GRT (4.3 +/- 1.4 h) was significantly (p less than 0.001) longer than the mean t1/2 (1.1 +/- 0.3 h); the GRT was prolonged compared with the t1/2 in each subject. In a randomized, crossover trial in 10 subjects, frequent feeding caused a dramatic prolongation in mean GRT of the capsule compared with the fasting state (greater than 14.5 vs. 0.5 h, p less than 0.005). In another crossover study in 6 subjects, the GRT of the capsule was evaluated after an overnight fast, a standard breakfast including solid food, and a liquid meal (i.e., 200 ml of diluted light cream). The mean GRT was 2.6 +/- 0.9 h after the liquid meal vs. 1.2 +/- 0.8 h after fasting (p less than 0.025). The mean GRT after the breakfast was 4.8 +/- 1.5 h, which was significantly greater than that after fasting (p less than 0.001) and after the liquid meal (p less than 0.01). These data suggest that the GRT of the Heidelberg capsule is a marker of the interdigestive migrating myoelectric complex in humans, the interdigestive migrating myoelectric complex can be markedly delayed by frequent feedings with solids, and the interdigestive migrating myoelectric complex is delayed by both liquid and solid meals.

Adult↗

PubMed2005

Hemodynamic mechanisms underlying the incomplete tolerance to caffeine's pressor effects.

Blood pressure (BP) and cardiovascular hemodynamics were assessed at baseline and after caffeine administration in a 4-week, placebo-controlled, double-blind, randomized, crossover trial of caffeine tolerance formation. Half of the subjects developed tolerance to the pressor effect of caffeine, whereas the other half continued to show increases in BP after caffeine ingestion (F = 16.7, p <0.0001). In the subjects who did not develop tolerance, peripheral resistance increased incrementally as the daily dose of caffeine increased (F = 2.8, p = 0.05).

Adult↗

PubMed1985

Piroxicam in primary dysmenorrhea.

Ninety-two patients with primary dysmenorrhea were included in a double-blind randomized crossover trial to study the efficacy of piroxicam on menstrual pain and associated symptoms, with placebo as control. Ninety patients completed the 4-month study period. Piroxicam afforded a highly significant relief from menstrual pain and reduced the need for the supplementary analgesic paracetamol. Piroxicam also had a significant effect on associated symptoms. The drug was well tolerated, with only a few side effects of a mild nature reported and with no difference between the piroxicam and placebo groups in this respect.

Adolescent↗