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PubMed1983

[Comparison of the anti-arrhythmic effects of propafenone and aprindine in the treatment of refractory chronic ventricular arrhythmias. A randomized double-blind crossover study controlled with placebo].

A placebo-controlled, randomized, double-blind, crossover study was performed in 14 patients with chronic, resistant, ventricular arrhythmias in order to evaluate the efficacy and safety of two new antiarrhythmic agents, propafenone and aprindine. After an initial placebo phase, patients received orally either propafenone (600 mg daily) or aprindine (150 mg daily for the first two days and 50 mg every 12 hours successively) for five days. This treatment was followed by a drug-free period (placebo II); patients were then crossed over to the alternative drug. A 24-hour Holter recording was performed during the last 48 hours of the initial placebo phase and on the final day of each phase of the crossover period. Analysis of Holter recordings revealed that the mean hourly PVCs frequency, for the group, was similar during the two control periods. Significant reduction in the mean hourly frequency of PVCs from control levels was observed in 78% of the patients during propafenone therapy and in 42% during aprindine therapy. For the whole group, propafenone induced a significant reduction of the average PVCs/h frequency (p less than 0.05), whereas the aprindine was ineffective. Finally no patient experienced side effects with propafenone, whereas aprindine caused side effects in three patients (dizziness, tremor, ataxy).

Adult↗
PubMed1997

Educational attainment, anger, and the risk of triggering myocardial infarction onset. The Determinants of Myocardial Infarction Onset Study Investigators.

BACKGROUND: While it has recently been shown that anger may trigger the onset of acute myocardial infarction, there has been no study of the role of socioeconomic factors in such triggering. Socioeconomic factors, such as educational attainment, may modulate the risk of triggering because of their influence on individual reactivity to external stressors and on the prevalence of traditional cardiac risk factors. OBJECTIVE: To evaluate the influence of educational attainment on the relative risk of myocardial infarction onset following episodes of anger. METHODS: We interviewed 1623 patients (501 women) an average of 4 days following a myocardial infarction. Data were collected on standard demographic variables as well as risk factors for coronary artery disease. Educational attainment was categorized into 3 levels: less than high school, completed high school, and at least some college. Anger was assessed by the Onset Anger Scale, a single-item, 7-level, self-report scale. Occurrence of anger in the 2 hours preceding the onset of myocardial infarction was compared with its expected frequency using self-matched control data based on the case-crossover study design. RESULTS: The risk of having a myocardial infarction triggered by isolated episodes of anger declined consistently and significantly with increasing levels of educational attainment (P = .03). The relative risk was twice as high among those with less than high school education (relative risk, 3.3; 95% confidence interval, 2.0-5.4) compared with patients with at least some college education (relative risk, 1.6; 95% confidence interval, 0.9-2.9). CONCLUSIONS: These findings indicate that socioeconomic factors are potent modulators of the risk of triggering acute cardiovascular disease onset. A better understanding of the physiological mechanisms underlying this association may lead to novel approaches to prevent acute cardiovascular events.

Adult↗
PubMed2003

Evaluation of parental preference for the treatment of asthmatic children aged 6 to 11 years with oral montelukast or inhaled cromolyn: a randomized, open-label, crossover study.

The objective of this study was to evaluate parental preference for the treatment of asthmatic children with oral montelukast sodium or inhaled cromolyn sodium. Additionally, we wanted to compare the two drugs in terms of patient preference for treatment, patient and parent satisfaction with treatment, frequency of inhaled albuterol use, adherence to treatment, and safety. This was a 12-week randomized, open-label, crossover study conducted in 42 primary care and asthma/allergy specialty centers in the United States. Three hundred thirty-three asthmatic patients, ages 6 to 11 years, who had a forced expiratory volume in 1 second (FEV1) of 60%-85% (inclusive) of predicted value with > or = 12% reversibility after administration of an inhaled beta-agonist and who used albuterol on at least 7 of the last 14 days of the run-in period. After a 2- to 3-week run-in period, patients were randomized either to 4 weeks of montelukast (5-mg chewable tablet once daily) followed by a 2-week washout period, then 4 weeks of cromolyn (two puffs 4 times daily from a metered-dose inhaler) or to the reverse sequence. More parents preferred montelukast (87%) than cromolyn (12%; p < 0.001). More patients preferred montelukast (82%) than cromolyn (17%; p < 0.001). Daily albuterol use (puffs/day) was reduced by 38% during montelukast therapy vs. 23% during cromolyn therapy. Seventy-eight percent of patients reported being highly adherent to montelukast therapy compared with 42% to cromolyn therapy (p < 0.001). Fewer patients receiving montelukast discontinued because of asthma exacerbation (1.0% vs. 5.0%, respectively), and fewer patients reported worsening asthma while receiving montelukast (3.5% vs. 7.5%, p = 0.036). Parents' and patients' preference, parents' and patients' satisfaction, and patients' adherence to therapy were all significantly better with oral montelukast compared with inhaled cromolyn. Beta-agonist use was decreased when taking montelukast, which was safe and well-tolerated.

Acetates↗
PubMed1979

Simple reaction time crossover occurs in schizophrenic outpatients.

A crossover pattern similar to that reported for inpatient schizophrenics (e.g., Bellissimo and Steffy 1972) has now been found for outpatients, and its frequency of occurrence in these outpatients is comparable to that reported for hospitalized patients by DeAmicas and Cromwell (1978). The process-reactive construct was unrelated to crossover in the current study, although crossover is found only in process patients in hospitalized samples. The difference in findings may be due to the insensitivity of the particular measure of this concept used here, or to the lack of validity for the construct in samples of chronic patients in the community and in treatment. The present results, together with DeAmicas and Cromwell's (1978) data suggestive of the presence of crossover in nondisturbed first degree relatives of schizophrenics, are consistent with an interpretation of this reaction time phenomenon as a behavioral marker of vulnerability. This hypothesis warrants study in a more extensive series of patients, and from a longitudinal perspective in which behavioral measures and clinical-social functioning variables are tracked across time.

Acoustic Stimulation↗
PubMed2000

Effects of individualized versus classical "relaxation" music on the frequency of agitation in elderly persons with Alzheimer's disease and related disorders.

Confusion and agitation in elderly patients are crucial problems. This study tested Gerdner's mid-range theory of individualized music intervention for agitation. An experimental repeated measures pretest-posttest crossover design compared the immediate and residual effects of individualized music to classical "relaxation" music relative to baseline on the frequency of agitated behaviors in elderly persons with Alzheimer's disease and related disorders (ADRD). Thirty-nine subjects were recruited from six long-term-care facilities in Iowa. The sample consisted of 30 women and 9 men (mean age 82 years) with severe cognitive impairment. Baseline data were collected for 3 weeks. Findings from the Modified Hartsock Music Preference Questionnaire guided the selection of individualized music. Group A (n = 16) received individualized music for 6 weeks followed by a 2-week "washout" period and 6 weeks of classical "relaxation" music. Group B (n = 23) received the same protocol but in reverse order. Music interventions were presented for 30 minutes, two times per week. The Modified Cohen-Mansfield Agitation Inventory measured the dependent variable. A repeated measures analysis of variance with Bonferroni post hoc test showed a significant reduction in agitation during and following individualized music compared to classical music. This study expands science by testing and supporting a theoretically based intervention for agitation in persons with ADRD.

Aged↗
PubMed2005

Efficacy of sacral nerve stimulation for fecal incontinence: results of a multicenter double-blind crossover study.

BACKGROUND AND AIMS: This is the first double-blind multicenter study examining the effectiveness of sacral nerve stimulation in a significant number of fecally incontinent patients. METHODS: A total of 34 consecutive patients (31 women), median age 57 years (range, 33-73 years), underwent sacral nerve stimulation for fecal incontinence. After implantation, 27 of 34 patients were randomized in a double-blind crossover design to stimulation ON or OFF for 1-month periods. While still blinded, the patients chose the period of stimulation (ON or OFF) that they had preferred. The mode of stimulation corresponding to the selected period was continued for 3 months (final period). Outcome measures were frequency of fecal incontinence and urgency episodes, delay in postponing defecation, score severity, feeling of improvement, preference for ON or OFF, quality of life, and manometric measurements. RESULTS: In the crossover portion of the study, the self-reported frequency of fecal incontinence episodes was significantly reduced during the ON versus the OFF period (P = 0.03), and this symptomatic improvement was consistent: 1) with the patients feeling of greater improvement during the ON versus OFF period (P = 0.02); 2) with the significant preference of patients (P = 0.02) for the ON versus OFF period. In the final period of the study, the frequency of fecal incontinence episodes decreased significantly (P = 0.005) in patients with the stimulator ON. The ability to postpone defecation (P = 0.01), the score for symptom severity (P = 0.0004), and the quality of life (P < 0.05) as well as anal sphincter function significantly improved. CONCLUSIONS: The significant improvement in FI during the ON versus OFF period indicated that the clinical benefit of sacral nerve stimulation was not due to placebo.

Adult↗
PubMed2004

Pain reducing effect of three types of transcutaneous electrical nerve stimulation in patients with chronic pain: a randomized crossover trial.

Transcutaneous electrical nerve stimulation (TENS) is a frequently applied therapy in chronic pain although evidence for effectiveness is inconclusive. Several types of TENS, based on different combinations of frequency, pulse duration and intensity, exist. The precise mechanism of action and the relevance of combinations of stimulus parameters are still unclear. To compare the effectiveness of three types of TENS we conducted a randomized, single blinded crossover trial. Patients received two times a 2-week period of daily TENS treatment, separated by a washout period of 2 weeks. In total, 180 chronic pain patients were randomized into three groups. In group 1, high frequency, low intensity TENS (HFT) was compared with high frequency, high intensity TENS (HIT). In groups 2 and 3, HFT and HIT were compared with a control TENS (COT). The order of applying the different modalities of TENS in each group was also randomized. Primary outcome was the patient's overall assessment of effectiveness and pain reduction (VAS). No differences were found in patient's assessment or pain reducing effect between the three groups, indicating no superiority of one type of TENS. In total, 56% continued TENS after the 2-week treatment period. At 6 months, 42% of all patients still used TENS. We concluded that there were no differences in effectiveness for the three types of TENS used in this study. Because no placebo group was included, no definite conclusions on effectiveness of TENS in general in the treatment of chronic pain could be made.

Adult↗
PubMed1988

Flunarizine in prophylaxis of childhood migraine. A double-blind, placebo-controlled, crossover study.

An 8-month, double-blind, placebo-controlled, crossover trial of flunarizine in the prophylaxis of migraine has been performed in 70 children. After 4 weeks of medication-free base-line observation, 35 children (group A) received flunarizine (5 mg/day) and 35 (group B) received placebo over a 12-week period. After a 4-week washout they crossed treatments for another 12 weeks. Sixty-three patients completed the trial. In both groups flunarizine significantly reduced the frequency and average duration of headache attacks. In group A efficacy was maintained after placebo crossover for the last 4 months of the study. Five subjects in group B stopped placebo because of ineffectiveness; two children in group A discontinued flunarizine treatment, one because of excessive daytime sedation and the other because therapy was ineffective. The main side effects were daytime sedation and weight gain. It is concluded that flunarizine is an effective drug for the treatment of childhood migraine. In a study of this length no serious side effects were discovered.

Child↗
PubMed2005

Metal dilution effects on the spin-crossover properties of the three-dimensional coordination polymer Fe(pyrazine)[Pt(CN)4].

The 1A1 left arrow over right arrow 5T2 spin transition has been investigated in the solid solutions of Fe(x)M(1-x)(pyrazine)[Pt(CN)4] (M = Ni or Co, 0 < or = x < or = 1) having a three-dimensional polynuclear structure. Both Ni and Co dilutions tend to decrease the hysteresis width and smooth the transition curves. The enthalpy (entropy) change associated with the spin transition was found to decrease from 26 kJ mol(-1) (84 J K(-1) mol(-1)) for x = 1 to 12 kJ mol(-1) (47 J K(-1) mol(-1)) for 47% Co dilution and to 15 kJ mol(-1) (54 J K(-1) mol(-1)) for 59% Ni dilution. Raman spectroscopy revealed a mixed one- and two-mode behavior in the solid solutions. For the first time, a correlation between vibrational frequencies exhibiting one-mode behavior and the entropy change, which drives the spin crossover, is established.

Journal Article↗
PubMed1989

Unequal crossover generates variation in ubiquitin coding unit number at the human UbC polyubiquitin locus.

An observed mRNA length polymorphism of the human UbC polyubiquitin gene transcript was shown to correlate exactly with a three-allele HaeIII RFLP. Both polymorphisms apparently result from a variation in the number of ubiquitin coding units per UbC allele. Transcriptionally active alleles containing seven, eight, or nine coding units were observed, at frequencies suggesting that alleles of higher coding-unit number are selectively retained in the population. We propose unequal crossover events, promoted by the highly repetitive structure of the polyubiquitin gene, as a basis for the coding-unit number variation, and we present preliminary evidence for such a crossover, on the basis of analysis of known UbC DNA sequences.

Biological Evolution↗
PubMed2003

Impact of bedtime snack composition on prevention of nocturnal hypoglycemia in adults with type 1 diabetes undergoing intensive insulin management using lispro insulin before meals: a randomized, placebo-controlled, crossover trial.

OBJECTIVE: To determine the impact of four bedtime (HS) snack compositions on nocturnal glycemic control, including frequency of hypoglycemia (<4 mmol/l) and morning hyperglycemia (>10 mmol/l), in adults with type 1 diabetes using lispro insulin before meals and NPH insulin at bedtime. RESEARCH DESIGN AND METHODS: Substitutions of 15 g carbohydrate (one starch exchange) for an equivalent amount of uncooked cornstarch or pure protein were compared to a standard snack (control: two starch + one protein exchange) and to no snack (placebo) in 15 adults using a randomized, cross-over design. All snacks were equivalent in kcal, fat, and total available glucose. An intravenous facilitated hourly blood glucose sampling during the night (11:00 P.M. to 7:00 A.M.). RESULTS: The glycemic level at bedtime (<7, 7-10, and >10 mmol/l) mediated the effects observed. A total of 14 hypoglycemic episodes, in 60% of patients, and 23 morning hyperglycemic episodes occurred over 50 nights. Most hypoglycemic episodes (10 of 14, 71%) occurred with no snack compared to any snack (P < 0.001) and at HS levels of <7 mmol/l (P = 0.05). The standard and protein snacks resulted in no nocturnal hypoglycemia at all HS glucose levels (P < 0.001). Only HS glucose >10 mmol/l was protective against hypoglycemia, even in the absence of a snack (P = 0.05); 46% of morning hyperglycemic episodes were associated (r = 0.37, P = 0.07) with this HS glucose level. CONCLUSIONS: The need for and composition of an HS snack depends on the HS glucose such that no snack is necessary at levels >10 mmol/l. At levels between 7 and 10 mmol/l, any snack is advised, and at <7 mmol/l, a standard or protein snack is recommended.

Adult↗
PubMed2003

The effect of growth hormone (GH) replacement therapy on sympathetic nerve hyperactivity in hypopituitary adults: a double-blind, placebo-controlled, crossover, short-term trial followed by long-term open GH replacement in hypopituitary adults.

OBJECTIVE: To test whether sympathetic nerve hyperactivity associated with adult hypopituitarism and untreated growth hormone (GH) deficiency is affected by GH treatment. DESIGN AND METHODS: Sympathetic nerve activity to the muscle vascular bed (MSA) expressed as burst frequency (bursts/min) and incidence (bursts/100 heartbeats) was recorded in 10 hypopituitary patients (aged 48-69 years), before and after acute (1 week) randomized, double-blind, crossover treatment with a 1-month washout period and chronic (1 year) GH replacement treatment. RESULTS: MSA burst frequency and incidence remained unchanged from baseline values after the short-term treatment, but exhibited decreases in median values [from 53 to 47 bursts/min (P = 0.02) and from 85 to 70 bursts/100 heartbeats (P = 0.03), respectively] after 12 months of replacement therapy. Twenty-four-hour urinary excretion of nitrate increased after the short-term cross-over treatment and the long-term treatment (P = 0.04). Diastolic blood pressure and waist circumference decreased after the 12-month treatment (P = 0.02 and P = 0.04, respectively). No correlation was found between the reduction in MSA and the increase in 24-h urinary nitrate excretion, the decrease in diastolic blood pressure and waist circumference. CONCLUSIONS: The sympathoexcitation in adult GH deficiency and the modest decline in MSA seen after long-term GH replacement treatment may suggest that the somatotropic axis is involved in the regulation of central sympathetic outflow.

Aged↗
PubMed2001

In situ study of sucrose exposure, mutans streptococci in dental plaque and dental caries.

The purpose of this study was to investigate the relationship among frequency of sucrose exposure, mutans streptococci levels and dental caries. Adult volunteers took part in this crossover study performed in 4 phases of 28 days each. The volunteers wore intra-oral palatal appliances containing blocks of human dental enamel and dripped 20% sucrose solution onto the dental blocks from 0 to 8 times/day. After each phase, the colony forming units (CFU) were determined in dental plaque and enamel dental caries was evaluated using cross-sectional hardness. Sucrose frequency had no statistically significant effect on mutans streptococci levels. In the enamel cross-sectional hardness tests, significant differences (p < 0.05) in relation to area of mineral loss were observed only when sucrose exposure was 8 times/day. Similar results were obtained when cross-sectional hardness was assessed at each distance from enamel surface.

Adult↗
PubMed1992

The comparative efficacy of various multiple-dose activated charcoal regimens.

Multiple-dose activated charcoal therapy is used in the management of poisoning emergencies to enhance the elimination of enterohepatically and enteroenterically secreted toxins. This study was conducted to determine if increasing the frequency of activated charcoal administration would enhance the elimination of a toxin. In this crossover study, five healthy adult volunteers were randomly assigned to either a control phase or one of three study phases. Subjects in the control phase and each of the study phases received an intravenous infusion of aminophylline (8 mg/kg). During the study phases each subject additionally received activated charcoal 50 gm and activated charcoal 12.5 gm every hour, 25 gm every 2 hours, or 50 gm every 4 hours over a 8-hour period for a cumulative activated charcoal dose of 150 gm. Ten blood samples were obtained over 12 hours and analyzed for theophylline concentrations. Using area under the curve and half-life calculations it was determined that each of the dosage regimens significantly reduced the reabsorption of theophylline and the plasma half-life when compared with control. There were no significant differences between any of the treatment groups. Decreasing the dose but increasing the frequency of activated charcoal administration is as effective as the traditional every 4 hour-therapy regimen.

Administration, Oral↗
PubMed1997

Partial liquid ventilation: a comparison using conventional and high-frequency techniques in an animal model of acute respiratory failure.

OBJECTIVE: To test the hypothesis that high-frequency ventilation (HFV), when compared with conventional techniques, enhances respiratory gas exchange during partial liquid ventilation (PLV). DESIGN: A four-period crossover design. SETTING: Animal research laboratory of Children's Health Care-St. Paul. SUBJECTS: Thirty-two newborn piglets, weighing 1.40 +/- 0.39 kg. INTERVENTIONS: Animals were divided into four groups of eight animals: a) PLV with high-frequency jet ventilation; b) PLV with jet ventilation using a background intermittent mandatory ventilation (IMV) rate; c) PLV with high-frequency oscillation; or d) PLV with high-frequency flow interruption using a background IMV rate. After anesthesia, paralysis, and tracheotomy, a normal saline wash procedure produced lung injury. Perfluorocarbon was then instilled via the endotracheal tube in an amount estimated to represent functional residual capacity. Animals received randomly either PLV using conventional techniques or PLV using the selected HFV technique as initial treatment. Then, animals were crossed over to the alternative treatment at equal mean airway pressure, as measured at the endotracheal tube tip. This sequence was repeated for a total of four crossover periods, such that all animals were treated twice with PLV using conventional techniques and twice with PLV using HFV. MEASUREMENTS AND MAIN RESULTS: We measured airway pressures at the endotracheal tube tip, aortic and central venous blood pressures, arterial blood gases, and respiratory system mechanics at baseline, after induction of lung injury, and at specified intervals throughout the experiment. Measurements were made before and 15 mins after crossovers, then ventilators were adjusted to normalize gas exchange. Measurements were again made 30 mins later, at the end of the treatment period. All types of PLV provided adequate gas exchange. Only PLV using jet ventilation with IMV produced gas exchange equal to that seen during PLV using conventional techniques at equivalent mean airway pressure. By the end of the treatment periods, only PLV using high-frequency oscillation continued to require higher airway pressure than PLV using conventional techniques for equivalent gas exchange. CONCLUSIONS: Gas exchange was not enhanced during PLV-HFV. Application of HFV with PLV provides no clear acute physiologic advantages to PLV using more conventional techniques.

Animals↗
PubMed1993

Effect of oral captopril on premature ventricular complexes in patients with preserved left ventricular systolic function: a randomized clinical trial.

Some studies have suggested that angiotensin-converting enzyme (ACE) inhibition in patients with heart failure is associated with a decrease in frequency of spontaneous premature ventricular complexes (PVCs). It is not clear whether such a finding represents a primary effect of ACE inhibition or, instead, a secondary result of treatment of heart failure. For a primary drug effect to be present, PVC suppression during ACE inhibition should also occur in patients with preserved left ventricular systolic function. We therefore undertook a randomized double-blind placebo-controlled crossover clinical trial to assess the effect of oral captopril (50 mg. b.i.d.) on ventricular arrhythmia frequency in 11 patients with > 30 PVCs/h (during a 48-h ambulatory recording) and a left ventricular ejection fraction of > or = 45% (measured by radionuclide multigated acquisition scan). Pharmacologic activity of the administered drug was evidenced by an increase in median plasma renin activity to 2.4 ng/AI/ml/h from a value of 1.1 ng/AI/ml/h during placebo (p = 0.001) and an 8.5 +/- 10.3 drop in mean diastolic blood pressure during captopril versus placebo (p < 0.03). During captopril treatment, a mean of 491 +/- 378 PVCs/h were observed compared with 389 +/- 169 PVCs/h during placebo, a nonsignificant difference. There was also no significant change in left ventricular ejection fraction, plasma catecholamines, or serum potassium during captopril treatment. Thus, ACE inhibition in patients with preserved left ventricular systolic function fails to suppress ventricular ectopic activity. Extrapolated to patients with heart failure, our observations argue against a primary PVC suppressive action of ACE inhibitors but do not rule out possible secondary antiarrhythmic effects of these agents.

Administration, Oral↗
PubMed1995

Adjunctive treatment of partial seizures with tiagabine: a placebo-controlled trial.

Tiagabine is a new antiepileptic drug which acts by a novel mechanism, inhibiting the reuptake of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) into neurons and glia. A double-blind, placebo-controlled, crossover trial was undertaken, based upon a response-dependent design. Ninety-four patients with complex partial seizures with or without secondary generalised tonic-clonic seizures were recruited into an open screening phase and tiagabine was added to their existing drug therapy in doses titrated to reduce seizure frequency by > or = 25% or to the limit of tolerance. Forty-six responders were subsequently randomised to a double-blind crossover trial in which tiagabine was compared with placebo. Forty-two patients completed the trial. A significant reduction in the frequency of complex partial and secondary generalised tonic clonic seizures was seen. Twenty-six percent had a reduction of > or = 50% in the frequency of their complex partial seizures, and of the 27 patients who also had secondary generalised tonic clonic seizures, 63% experienced a reduction of > or = 50%. No interactions with baseline antiepileptic drugs were detected and no serious adverse reactions occurred. The commonest adverse events were tiredness, dizziness and headache. We conclude that tiagabine has promising antiepileptic effects. Further trials are underway.

Adolescent↗
PubMed1998

Gabapentin in orthostatic tremor: results of a double-blind crossover with placebo in four patients.

We treated four patients affected by orthostatic tremor (OT) with gabapentin in increasing doses (300 to 2,400 mg/d). OT was evaluated with patients' self-monitoring scales, tremor rating scales, electromyography (EMG) showing the 14- to 18-Hz frequencies, and EMG frequency analysis. All patients had transitory responses to clonazepam. Gabapentin induced disappearance of OT in three patients and consistent reduction in one. Crossover to placebo induced reappearance of tremor.

Acetates↗