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Results for “randomized crossover trial”

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At least 829 records · Page 46Linked to original sources

PubMed1999

Pelvic restraint effect on lumbar gluteal and hamstring muscle electromyographic activation.

OBJECTIVE: To evaluate the influence of pelvic restraint on electromyographic activation (neural drive) of the lumbar extensor, gluteal, and hamstring muscles during submaximal dynamic lumbar extension in an upright seated position. DESIGN: Randomized, balanced, crossover trial comparing the electromyographic activation of the lumbar, gluteal, and hamstring muscles during dynamic lumbar extension exercise with and without pelvic restraint. SETTING: Research laboratory at a private research university. SUBJECTS: Twelve apparently healthy men (ages 18 to 50 yrs). INTERVENTION: Dynamic lumbar extension exercises. MAIN OUTCOME MEASURE: Electromyographic recordings. RESULTS: Pelvic restraint did not influence the relative activation of the lumbar, gluteal, or hamstring muscle groups (p< or =.05) during submaximal dynamic lumbar extension exercise. The relative activation of the gluteal muscles was significantly lower than that of the lumbar extensor and hamstring muscle groups. CONCLUSIONS: Pelvic restraint is not a requirement to promote neural drive to the lumbar musculature during submaximal dynamic lumbar extension exercise performed in an upright seated position. Submaximal lumbar extension exercise reduces the relative contribution of the gluteal muscles compared with a maximal voluntary isometric contraction.

Adult↗

PubMed1997

Metabolic abnormality of calf skeletal muscle is improved by localised muscle training without changes in blood flow in chronic heart failure.

OBJECTIVE: To investigate whether localised skeletal muscle training, which does not have a great influence on the heart, improves abnormalities of calf muscle metabolism in patients with chronic heart failure. METHODS: Seven cardiac patients in New York Heart Association class II and III undertook a random order crossover trial. Training consisted of unilateral calf plantar flexion exercise. Before and after training, the patients' metabolic responses were examined during the calf exercise test with phosphorus-31 nuclear magnetic resonance spectroscopy (31P-MRS) and calf blood flow with plethysmography. The new Borg scale was employed as a subjective fatigue scale. RESULTS: In a constant load exercise test (70% of maximum load achieved during the incremental exercise), standardised phosphocreatine and intracellular pH decreased less after training (p < 0.05, repeated measures analysis of variance). The new Borg scale improved significantly after training (p < 0.05). Blood flow did not change significantly in either test. CONCLUSIONS: In patients with chronic heart failure, localised calf skeletal muscle training improved oxidative capacity without changes in calf blood flow. This training also improved the subjective fatigue scale. This training method may therefore alleviate leg fatigue experienced in daily activities.

Aged↗

PubMed1999

Comparative efficacy and tolerability of low-dose pravastatin versus lovastatin in patients with hypercholesterolemia.

BACKGROUND: The HMG CoA reductase inhibitors have quickly become the most widely prescribed family of agents for the treatment of patients with elevated low-density lipoprotein (LDL) cholesterol. The incidence of side effects with these agents increases as the dose increases within the recommended dosage range. A lower dosage presumably would have a lower incidence of adverse effects. In addition, lower doses should translate into reduced drug costs. METHODS AND RESULTS: We compared the efficacy of 10 mg of pravastatin and 10 mg of lovastatin in a randomized, crossover design trial among 30 patients with hypercholesterolemia. At baseline, their total cholesterol and LDL cholesterol levels were 249.0 +/- 27.3 and 185.1 +/- 25.5 mg/dL. After 4 weeks of treatment with lovastatin, the total cholesterol and LDL cholesterol levels fell to 202.8 +/- 29.6 and 141.0 +/- 25.3 mg/dL, decreases of 19% and 24%, respectively. Four weeks of pravastatin treatment resulted in levels of 212.6 +/- 30.8 and 150.5 +/- 25.5 mg/dL, or 15% and 19%, respectively. CONCLUSIONS: There were highly significant changes in total cholesterol and LDL cholesterol levels with each agent and no differences in effect between the 2 agents. In 13 (43%) of the 30 patients, LDL levels were reduced to </=130 mg/dL with one of the agents. Both agents were generally well tolerated, with no clinically important change in liver function tests or creatinine kinase levels.

Aged↗

PubMed1995

Replacement of dehydroepiandrosterone enhances T-lymphocyte insulin binding in postmenopausal women.

OBJECTIVE: To demonstrate bioavailability of 3 weeks of oral micronized DHEA and to delineate changes induced on insulin sensitivity, morphometric indexes, and lipoprotein profiles. DESIGN: Oral micronized DHEa (50 mg/d) was administered in 3-week treatments to 11 postmenopausal women in a prospective, placebo-controlled, randomized, blinded, crossover trial with an interarm washout. After dose (23 hour) serum DHEA, DHEAS, T, and cortisol levels were measured, as were fasting lipoproteins, oral glucose tolerance tests (OGTT), T-lymphocyte insulin binding and degradation, and urine collagen cross-links. Morphometric changes were determined by hydrostatic weighing. RESULTS: Dehydroepiandrosterone sulfate, DHEA, T, and free T increased up to two times premenopausal levels with treatment. Fasting triglycerides declined; no change in collagen cross-links or morphometric indexes was noted. Oral glucose tolerance test parameters did not change, but both T-lymphocyte insulin binding and degradation increased with DHEA. CONCLUSION: Fifty milligrams per day of oral DHEA gives suprahysiologic androgen levels; 25 mg/d may be more appropriate. Dehydroepiandrosterone enhanced tissue insulin sensitivity and lowered serum triglycerides. Rationale is provided for postmenopausal replacement therapy with this androgen.

Aged↗

PubMed1995

Comparison of the nicotine pharmacokinetics of Nicoderm (nicotine transdermal system) and half-hourly cigarette smoking.

Nicoderm, a nicotine transdermal system (NTS), provides a continuous, transdermal delivery of nicotine and is used as an aid to smoking cessation. In contrast, cigarette smoking yields nicotine concentrations in plasma that rise and fall with each cigarette. The primary objective of this study was to compare nicotine pharmacokinetics after treatment of subjects with either the NTS or controlled smoking. Fourteen healthy adult male smokers, who smoked at least 30 cigarettes per day, were entered into a randomized crossover design trial that compared the NTS, 21 mg/day applied for 24 hours, with half-hourly smoking during the day. Subjects abstained from smoking for 2 days, and were treated for 5 days with either the NTS (daily) or controlled smoking (30 cigarettes at half-hourly intervals on days 1 and 5; ad libitum smoking on days 2-4). Blood samples were obtained frequently on days 1 and 5 for analysis of nicotine and cotinine. Pharmacokinetic comparisons showed that nicotine Cmax, area under the curve (AUC)inf, and Cavg for the NTS were lower than corresponding values for controlled smoking; Cmax and Cavg values were approximately half those of smoking. Cmax and Cavg values for cotinine were similarly lower for the NTS compared to controlled smoking. For both treatments, plasma nicotine concentrations were higher on day 5 compared to day 1. Thus, the NTS provides concentrations of nicotine that are lower than smoking.

Administration, Cutaneous↗

PubMed1981

The influence of supplemental sodium acetate on carbonic anhydrase inhibitor-induced side effects.

A double-masked, randomly assigned, crossover trial of the effect of supplemental two-weak courses of sodium acetate (90 mEq/day) and placebo on carbonic anhydrase inhibitor (CAI)-induced side effects of malaise, fatigue, and others ("malaise symptom complex") was performed in 28 patients. Fifteen patients (54%) experienced significant improvement while receiving supplemental sodium acetate compared with five (18%) receiving a placebo. A relationship was observed between the clinical efficacy of the acetate supplementation and the measured improvement in serum carbon dioxide combining power. No changes in intraocular pressure were observed when supplemental sodium acetate was given. The results confirm the beneficial effect of supplemental alkalinization for such CAI-induced symptoms in somewhat less than half of the affected patients and suggest the need for long-term studies in which the dosage of sodium acetate is titrated in relation to measured changes in the level of metabolic acidosis.

Acetates↗

PubMedDate not supplied

Bioavailability of beta-aescin from horse chestnut seed extract: comparative clinical studies of two Galenic formulations.

The bioavailability of beta-aescin--the main active constituent of horse chestnut seed extract--in a nonretarded test medication in comparison with that in a retarded reference formulation was evaluated in 2 randomized crossover clinical trials involving 18 healthy volunteers each. Serum concentration/time curves derived under steady-state conditions and pharmacokinetic parameters measured during both studies showed no significant difference between absorption rates for the retarded versus nonretarded preparation. In the first study, investigators found a test-to-reference ratio of 1.06 (90% confidence interval [CI] range: 99-113) for the area under the curve (AUC; the primary outcome measure). Absorption rates were diminished during the night compared with daytime rates for both study preparations. In the second study, using AUC and maximum concentration (Cmax) as the primary characteristics, investigators analyzed bioavailability based on the mean of 2 consecutive daytime periods and obtained estimates of 1.07 for AUC (90% CI range: 0.96-1.19) and 1.05 for Cmax (90% CI range: 0.90-1.21). Bioequivalence of the test and reference drug preparations was thus established according to the Note for Guidance on the Investigation of Bioavailability and Bioequivalence. Both treatments were equally well tolerated.

Adult↗

PubMed1986

Oral haloperidol lowers human intraocular pressure.

This is a double masked, randomized, crossover design trial of orally administered haloperidol in human volunteers. There was a statistically significant drop of the intraocular pressure in non-glaucomatous volunteers at 3 and 4 hours following haloperidol administration. Glaucomatous patients on topical medications did not show a statistically significant drug effect. Non-glaucomatous volunteers showed a statistically significant decrease in pupillary diameter 3 hours following haloperidol administration while glaucomatous subjects showed no significant change in pupillary diameter. There were no significant changes in the near point of accomodation. Dopamine antagonists like haloperidol may act by blocking post-synaptic dopamine receptors in the ciliary body, resulting in vasoconstriction and subsequently decreased aqueous humor production. Pharmacologic data from human use suggests that ocular side effects of topically administered haloperidol may be less than those of pilocarpine, while systemic side effects may be less than those of timolol. Haloperidol may become a cost-effective, once daily ocular hypotensive agent. Problems with preparation of a viable topical vehicle, as well as potential long-term side effects will require a great deal of further investigation.

Administration, Oral↗

PubMed2006

Free fatty acids increase androgen precursors in vivo.

CONTEXT: There is considerable evidence that metabolic factors such as insulin resistance may induce hyperandrogenemia in polycystic ovary syndrome. However, other metabolic factors such as free fatty acids (FFAs) may also contribute to androgen excess. OBJECTIVE: The objective was to study effects of FFAs on adrenal production of androgen precursors in vivo. DESIGN AND PARTICIPANTS: We investigated eight healthy young men, because male individuals produce the androgen precursors dehydroepiandrosterone (DHEA), DHEA sulfate, and androstenedione predominantly in the adrenal gland. A randomized controlled crossover trial was performed. INTERVENTION: After a 10-h overnight fast, 20% lipid/heparin or saline/heparin infusion was given at a rate of 1.5 ml/min. Four hours after start of lipid infusion, a euglycemic hyperinsulinemic clamp was performed. MAIN OUTCOME MEASURES: DHEA, androstenedione, 17-OH-progesterone, testosterone, estrone, LH, FSH, ACTH, and cortisol were measured. RESULTS: The adrenal androgen precursors DHEA and androstenedione showed a circadian decline during saline/heparin infusion (P < 0.05 vs. baseline, respectively), whereas no significant changes were observed during lipid/heparin infusion (P = not significant vs. baseline, respectively). Correspondingly, DHEA and androstenedione values were significantly elevated during lipid compared with saline infusion (P < 0.05, respectively), and areas under curve of both androgen precursors were significantly increased with lipid compared with saline infusion. Notably, all changes were detected before induction of insulin resistance. CONCLUSIONS: This study demonstrates that FFAs increase production of androgen precursors in vivo in men. These data tentatively suggest that hyperandrogenemia in polycystic ovary syndrome may be induced, at least in part, by elevated FFAs.

17-alpha-Hydroxyprogesterone↗

PubMed2002

Economic evaluation of antineoplasic chemotherapy administered at home or in hospitals.

OBJECTIVES: Comparative economic evaluations of chemotherapy administered in hospital day-care units or in the home are relatively scarce. Furthermore, most existing evaluations do not include methodologic studies. This study seeks to compare the costs of anticancer chemotherapy with hospital at-home care versus a hospital day-care unit in the Rhône-Alpes region of France. METHODS: This study is based on a randomized controlled crossover trial that included 42 patients, to whom chemotherapy courses were alternatively given in both settings. All cost categories were taken into account according to microcosting methods. A detailed assessment was performed on coordination and health care in both structures (marginal costs and average costs), from the viewpoint of society. RESULTS: The marginal cost for one chemotherapy administration was significantly higher with hospital at-home care than in the hospital day-care unit ($232.5 vs. $157, p < .0001). Conversely, the average cost was significantly lower with home care than at the hospital ($252.6 vs. $277.3, p = .0002). CONCLUSIONS: The results show that the interest of developing home care in anticancer chemotherapy is questionable regarding costs. In the French healthcare system, where there is a surplus of hospital beds, marginal costs seem to be more relevant indicators in most cases than average costs.

Antineoplastic Agents↗

PubMed1990

Short term linear growth in asthmatic children during treatment with prednisolone.

OBJECTIVE: To see whether small daily doses of prednisolone have any adverse effect on short term linear growth in children with mild asthma. DESIGN: Double blind, random order crossover trial of two dosages of prednisolone. During run in and washout periods patients were given placebo. All treatment periods were of two weeks' duration. SETTING: Outpatient clinic referrals in a secondary referral centre. PATIENTS: 14 Children (10 boys) aged 7-11 years with normal growth velocity during the previous year, no signs of puberty, and no history of receiving systemic or topical steroids during the two months before the study. One child was excluded because his pulmonary function deteriorated and another was withdrawn because of varicella. INTERVENTIONS: 2.5 and 5.0 mg prednisolone daily given in divided dosage in the morning and evening. MAIN OUTCOME MEASURE: Growth of the lower leg as measured twice a week by knemometry. RESULTS: A significant reduction in mean growth velocity of the lower leg occurred in both prednisolone treatment periods. The mean difference between the run in period and the treatment period with 2.5 mg prednisolone daily was 0.63 mm/week (95% confidence interval 0.47 to 0.80 mm/week) and between the run in period and the treatment period with 5.0 mg prednisolone daily 0.57 mm/week (0.38 to 0.77 mm/week). CONCLUSION: Small daily doses of prednisolone suppress short term linear growth in children with mild asthma. The clinical relevance of this finding needs further study.

Adolescent↗

PubMed2004

Efficacy of positive airway pressure and oral appliance in mild to moderate obstructive sleep apnea.

The efficacy of currently recommended treatments is uncertain in patients with mild to moderate obstructive sleep apnea (apnea-hypopnea index [AHI], 5-30). A group of 114 sleep clinic patients with an AHI of 5-30 have participated in a randomized controlled crossover trial of 3 months of treatment with each of nasal continuous positive airway pressure (CPAP), a mandibular advancement splint, and a placebo tablet. Outcomes were sleep fragmentation and hypoxemia, daytime sleepiness, quality of life, neurobehavioral function, and blood pressure. Both active treatments improved sleep outcomes, but positive airway pressure had a greater effect. The quality of life, symptoms, and subjective but not objective sleepiness improved to a similar degree with both treatments; however, many of the improvements seen in neuropsychologic function and mood were not better than the placebo effect. Some aspects of nocturnal blood pressure were improved with the splint but not with CPAP. This study has shown that although both CPAP and mandibular advancement splint effectively treated sleep-disordered breathing and sleepiness, the expected response in neurobehavioral function was incomplete. This may be due to the splint having a lesser therapeutic effect and CPAP being poorly tolerated and therefore used less in this patient group.

Continuous Positive Airway Pressure↗

PubMed2026

Potential Links Between Physiological and Perceptual Strain in High Heat Stress.

The physiological strain index (PhSI) is widely used to quantify thermoregulatory and cardiovascular strain during heat stress. However, direct physiological measurements may not always be feasible in occupational or athletic settings. Therefore, this study aimed to examine the relationship and agreement between perceptual strain and integrated physiological strain indices during high heat stress. Ten healthy, physically active, non-heat-acclimated males (29 (7) yr; 1.79 (0.11) m; 77.4 (9.3) kg) completed two randomized crossover exercise trials in hot-dry (HD) and warm-humid (WH) environments with equivalent wet-bulb globe temperatures. Heart rate, rectal temperature, skin temperature, rating of perceived exertion, and thermal sensation were measured at baseline and every 15 minutes during 60 minutes of cycling. Physiological strain index (PhSI), adaptive physiological strain index (aPhSI), and perceptual strain index (PeSI) were calculated using validated equations. Repeated-measures correlation analyses demonstrated very strong associations between PeSI and both PhSI and aPhSI under HD (Rrm = 0.940-0.943) and WH (Rrm = 0.980-0.982; all p < 0.001). Receiver operating characteristic analyses demonstrated good-to-excellent discrimination of physiological strain by PeSI (AUC = 0.895-0.969). Mixed-effects analyses showed that higher PeSI values were associated with increased PhSI (β = 1.325, p < 0.001) and aPhSI (β = 1.459, p < 0.001). However, Bland-Altman analyses demonstrated relatively small mean biases (0.4-0.9 AU) but wide limits of agreement (-2.8 to 4.2 AU), indicating that PeSI and physiological strain indices are not interchangeable. These findings suggest that PeSI may serve as a practical adjunctive or screening indicator of physiological strain when direct physiological measurements are unavailable.

Humans↗

PubMed1983

Comparison of chlorthalidone and spironolactone in low--renin essential hypertension.

Nineteen patients with uncomplicated essential hypertension and low activity of plasma renin in response to a change from recumbency to an upright posture along with furosemide administration were given spironolactone, 400 mg/d, or chlorthalidone, 100mg/d, in a double-blind, random-sequence, crossover trial. The sequence of treatments was placebo for 2 months, one active drug for 2 months, placebo again for 1 month and the other active drug for 2 months. With both active treatments the average systolic, diastolic and mean arterial pressures decreased significantly. The two agents were equally efficacious in lowering the blood pressure regardless of the severity of hypertension during placebo treatment. Body weight, 24--hour urinary excretion of sodium, the plasma renin activity and the plasma aldosterone level at the end of the initial placebo period did not allow us to predict the response to either drug. Both drugs reduced the body weight and increased the stimulated plasma renin level activity. Chlorthalidone significantly increased the serum uric acid level and significantly reduced the serum potassium level. Three patients experienced orthostatic dizziness during spironolactone therapy, but no adverse symptoms were observed with chlorthalidone therapy. Thus, spironolactone is an effective alternative to thiazide-type drugs in patients with low-renin essential hypertension.

Adult↗

PubMedDate not supplied

Oxcarbazepine (GP 47.680): a possible alternative to carbamazepine?

A double-blind randomized crossover design trial of carbamazepine (CBZ) and oxcarbazepine (OCBZ) was performed with 48 in-patients with epilepsy. All were stabilized on polytherapy including CBZ and had at least two seizures per week. CBZ was replaced by the trial medication. Each trial period started with a titration, followed by a 12-week steady state. Concomitant medications were kept constant during the trial. The criteria for assessment were seizure fit frequency and severity; tolerability; hematology and blood chemistry; plasma levels of antiepileptic drugs; EEG; cardiovascular parameters; and treatment preference. The following differences regarding OCBZ were detected: 9% reduction of the total number of seizures, with a significant reduction of tonic-clonic (20%) and tonic (31%) seizures; increased alertness and concentration ability in five patients; an allergic skin reaction with CBZ that completely disappeared in two patients while receiving OCBZ; an increase of valproate and phenytoin plasma levels in a number of patients, probably caused by reduced enzyme induction; a slight but significant reduction of serum Na, not causing clinical symptoms; less seizures than in the CBZ period in 25 patients (52%); and a preference for OCBZ in 23 patients (48%). We consider OCBZ at least as effective as CBZ with a slightly better tolerability. In severe cases, the wider therapeutic window might improve seizure control.

Adolescent↗

PubMedDate not supplied

Comparison of wire-guided cricothyrotomy versus standard surgical cricothyrotomy technique.

We compared a wire-guided cricothyrotomy technique vs. standard surgical cricothyrotomy in terms of accuracy in placement, complications, performance time, incision length, and user preference. We conducted a randomized, crossover controlled trial in which Emergency Medicine (EM) attendings and residents performed cricothyrotomies by both standard and wire-guided techniques (using a commercially available kit) on human cadavers after a 15-min training session. Procedure time, incision length, and physician preference were recorded. Cadavers were inspected for accuracy of placement and complications. Airway placement was accurate in 13 of 15 cases for the standard technique (86.7%), and 14 of 15 cases for the wire-guided technique (93.3%). When comparing wire-guided vs. standard techniques, there were no differences in complication rates or performance times. The wire-guided technique resulted in a significantly smaller mean incision length than the standard technique (0.53 vs. 2.53 cm, respectively, p<0.0001). Overall, 14 of 15 physicians stated that they preferred the wire-guided to the standard technique. Our data suggest that this wire-guided cricothyrotomy technique is as accurate and timely to use as the standard technique and is preferred by our physician operators. In addition, the technique results in a smaller incision on human cadaver models.

Attitude of Health Personnel↗

PubMed1996

The efficacy of a standard training program for transillumination-guided endotracheal intubation.

OBJECTIVE: To evaluate the success rate, intubation time, and complication rate of transillumination-guided intubation following two hours of instruction in the use of the Trachlight (TL) device. METHODS: A prospective, randomized crossover laboratory trial was conducted at an emergency medical service training site with 30 nonpaid volunteer paramedic students, one month prior to their graduation. The students were instructed in the use of the TL in a standardized curriculum consisting of didactic, video, and demonstration sessions. Each student was required to successfully intubate a training manikin with the TL five times. Approximately three weeks later, the students were asked to intubate the manikin 20 times, alternating between direct laryngoscopy (DL) and TL. RESULTS: The success rates were 94% for DL and 63% for TL (p < 0.0001). The mean intubation times were 14.6 seconds for DL and 16.8 seconds for TL (p < 0.001). The incidences of trauma were 7.3% for DL and 1.4% for TL (p < 0.001). CONCLUSION: A two-hour training session, including five successful light-guided intubations using the TL, was inadequate for producing acceptable success rates during manikin intubations by paramedic students. While TL intubation intervals were shorter when successful, the 2.2-second difference was not clinically meaningful. The incidence of trauma in our manikin model during TL intubations was significantly lower than that with DL.

Cross-Over Studies↗

PubMed2000

Intrathecal baclofen for the treatment of dystonia in patients with reflex sympathetic dystrophy.

BACKGROUND AND METHODS: Patients with reflex sympathetic dystrophy (also known as the complex regional pain syndrome) may have dystonia, which is often unresponsive to treatment. Some forms of dystonia respond to the intrathecal administration of baclofen, a specific gamma-aminobutyric acid-receptor (type B) agonist that inhibits sensory input to the neurons of the spinal cord. We evaluated this treatment in seven women who had reflex sympathetic dystrophy with multifocal or generalized tonic dystonia. First, we performed a double-blind, randomized, controlled crossover trial of bolus intrathecal injections of 25, 50, and 75 microg of baclofen and placebo. Changes in the severity of dystonia were assessed by the woman and by an investigator after each injection. In the second phase of the study, six of the women received a subcutaneous pump for continuous intrathecal administration of baclofen and were followed for 0.5 to 3 years. RESULTS: In six women, bolus injections of 50 and 75 microg of baclofen resulted in complete or partial resolution of focal dystonia of the hands but little improvement in dystonia of the legs. During continuous therapy, three women regained normal hand function, and two of these three women regained the ability to walk (one only indoors). In one woman who received continuous therapy, the pain and violent jerks disappeared and the dystonic posturing of the arm decreased. In two women the spasms or restlessness of the legs decreased, without any change in the dystonia. CONCLUSIONS: In some patients, the dystonia associated with reflex sympathetic dystrophy responds markedly to intrathecal baclofen.

Adult↗