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PubMed1986

Randomized clinical trials: alternatives to conventional randomization.

The randomized allocation format remains an exceedingly powerful tool for clinical research. Because humans are the subjects in clinical research, this area of scientific study must operate within the limits dictated by such basic principles as individual autonomy, justice, and beneficence. As randomized studies have become more common in clinical research, it has become apparent that there is often need for modification of the basic randomized format or for alternatives. The most widespread modification is the use of sequential analyses to monitor the progress of a trial and ensure early identification of either unanticipated adverse effects or more pronounced differences than expected. Although this modification does not affect the basic randomized allocation format, it does provide a protection that is lacking in the conventional trial and should be utilized whenever feasible. Modifications that do affect the basic structure of the randomized trial include adaptive allocation and pre-randomization. The former is attractive and useful but limited to studies in which results from early enrollees are known before late enrollees are allocated. The greater the linkage between preceding subject results and subsequent assignments, the greater is the protection afforded by such a format. Pre-randomization, more universally applicable than adaptive allocation, suffers from pronounced cross-over potential and has been criticized on ethical grounds, a combination of weaknesses that raises questions of whether pre-randomization truly offers advantages to conventional randomized formats. True alternatives to the randomized format include the self-controlled study and the historical control design. Both possess significant ethical advantages over the simple randomized study. Unfortunately, both are at some methodological disadvantage when the same comparison is made. The self-controlled study is limited to the study of conditions sufficiently stable or recurrent that they permit two or more treatment courses in a single patient. In emergency medicine and critical care, this description fits only a small proportion of the illness spectrum. This design is underutilized in clinical research focused on less severe problems of the type seen in ambulatory and primary-care settings. Such problems can be suitable topics for research by emergency medicine specialists. Historical control studies are eminently applicable in the emergency and critical-care setting.(ABSTRACT TRUNCATED AT 400 WORDS)

Antihypertensive Agents↗

PubMed2000

Intravenous or enteral loop diuretics for preterm infants with (or developing) chronic lung disease.

BACKGROUND: Lung disease in preterm infants is often complicated with lung edema. OBJECTIVES: The aim of this review was to assess the risks and benefits of administration of a diuretic acting on the loop of Henle (loop diuretic) in preterm infants with or developing chronic lung disease (CLD). Primary objectives were to assess changes in need for oxygen or ventilatory support and effects on long-term outcome, and secondary objectives were to assess changes in pulmonary mechanics and potential complications of therapy. SEARCH STRATEGY: We used the standard search method of the Cochrane Neonatal Review Group. We used the following keywords: ¿ or ¿ and , limited to and limited to or . We searched Medline (1966-1998), Embase (1974-1998) and the Cochrane Controlled Trials Register (CCTR) from the Cochrane Library (1998, issue 4). In addition, we hand searched several abstract books of national and international American and European Societies. SELECTION CRITERIA: We included in this analysis trials in which preterm infants with or developing chronic lung disease and at least 5 days of age were all randomly allocated to receive a loop diuretic either enterally or intravenously. Eligible studies needed to assess at least one of the outcome variables defined a priori for this systematic review. Primary outcome variables included important clinical outcomes, and secondary outcome variables included toxicity and pulmonary mechanics (e.g., lung compliance and airway resistance). DATA COLLECTION AND ANALYSIS: We used the standard method for the Cochrane Collaboration which is described in the Cochrane Collaboration Handbook. Two investigators extracted, assessed and coded separately all data for each study, using a form that was designed specifically for this review. Any disagreement was resolved by discussion. We combined parallel and cross-over trials and, whenever possible, transformed baseline and final outcome data measured on a continuous scale into change scores using Follmann's formula. MAIN RESULTS: The only loop diuretic used in the studies which met the selection criteria was furosemide. Most studies focused on pathophysiological parameters and did not assess effects on important clinical outcomes defined in this review, or the potential complications of diuretic therapy. In preterm infants < 3 weeks of age developing CLD, furosemide administration has either inconsistent effects or no detectable effect. In infants > 3 weeks of age with CLD, a single intravenous dose of 1 mg/kg of furosemide improves lung compliance and airway resistance for 1 hour. Chronic administration of furosemide improves both oxygenation and lung compliance. REVIEWER'S CONCLUSIONS: In preterm infants > 3 weeks of age with CLD, acute and chronic administration of furosemide improve lung compliance. Chronic administration of intravenous or enteral furosemide improves oxygenation. In view of the lack of data from randomized trials concerning effects on important clinical outcomes, routine or sustained use of systemic loop diuretics in infants with (or developing) CLD cannot be recommended based on current evidence. Randomized trials are needed to assess the effects of furosemide administration on survival, duration of ventilatory support and oxygen administration, length of hospital stay, potential complications and long-term outcome.

Chronic Disease↗

PubMed2000

Diuretics acting on the distal renal tubule for preterm infants with (or developing) chronic lung disease.

OBJECTIVES: The aim of this review is to assess the risks and benefits of diuretics acting on distal segments of the renal tubule (distal diuretics) in preterm infants with or developing chronic lung disease (CLD). Primary objectives are to assess changes in need for oxygen or ventilatory support and effects on long-term outcome, and secondary objectives are to assess changes in pulmonary mechanics and potential complications of therapy. SEARCH STRATEGY: We used the standard method of the Cochrane Neonatal Review Group. We used the following keywords: ¿ or ¿ and , limited to and limited to or . We searched Medline (1966-1998), Embase (1974-1998) and the Cochrane Controlled Trials Register (CCTR) from the Cochrane Library (1999, issue 2). In addition, we hand searched several abstract books of national and international American and European Societies. SELECTION CRITERIA: We included in this analysis trials in which preterm infants with or developing CLD and at least five days of age were all randomly allocated to receive a distal diuretic (i.e., a diuretic acting on the distal renal tubule). Eligible studies needed to assess at least one of the outcome variables defined a priori for this systematic review. Primary outcome variables included changes in need for respiratory support and oxygen supplementation, mortality, bronchopulmonary dysplasia (BPD), death or BPD, chronic lung disease at 36 weeks of postconceptional age (gestational age + postnatal age), length of stay, and number of rehospitalizations during the first year of life. Secondary outcome variables included pulmonary mechanics and potential complications of therapy. DATA COLLECTION AND ANALYSIS: We used the standard method for the Cochrane Collaboration which is described in the Cochrane Collaboration Handbook. Two investigators extracted, assessed and coded separately all data for each study, using a form that was designed specifically for this review. Any disagreement was resolved by discussion. We combined parallel and cross-over trials and, whenever possible, transformed baseline and final outcome data measured on a continuous scale into change scores using Follmann's formula. MAIN RESULTS: Of six studies fulfilling entry criteria, most focused on pathophysiological parameters and did not assess effects on important clinical outcomes defined in this review, or the potential complications of diuretic therapy. In preterm infants > 3 weeks of age with CLD, a four-week treatment with thiazide and spironolactone improved lung compliance and reduced the need for furosemide. Thiazide and spironolactone decreased the risk of death and tended to decrease the risk for lack of extubation after 8 weeks in intubated infants. There is no evidence to support the hypothesis that adding spironolactone to thiazide or that adding metolazone to furosemide improves the outcome of preterm infants with CLD. REVIEWER'S CONCLUSIONS: In preterm infants > 3 weeks of age with CLD, acute and chronic administration of distal diuretics improve pulmonary mechanics. Chronic administration of diuretics (thiazide with spironolactone) reduces mortality in intubated patients. Large studies are needed to assess (1) whether chronic diuretic administration improves mortality, duration of oxygen dependency, ventilator dependency, length of hospital stay and long-term outcome in patients without long-term toxicity and (2) whether adding spironolactone to thiazides or adding metolazone to furosemide has any beneficial effect.

Chronic Disease↗

PubMed1988

Controlled clinical trial of complete open surgical drainage and of prednisolone in treatment of tuberculous pericardial effusion in Transkei.

240 patients with active tuberculous pericardial effusion received a 4-drug daily antituberculosis regimen for 6 months and have been studied for 24 months or longer. Those willing were randomly allocated to open pericardial biopsy and complete drainage of pericardial fluid on admission or percutaneous pericardiocentesis as required. All patients were randomly allocated to prednisolone or matching placebo for the first 11 weeks, on a double-blind basis. Complete open drainage on admission abolished the need for pericardiocentesis (p less than 0.01) but did not influence the need for pericardiectomy for subsequent constriction or the risk of death. Among patients who did not have open drainage on admission, 2 (3%) of 76 given prednisolone compared with 10 (14%) of 74 given placebo died of pericarditis (p less than 0.05), 6 (8%) and 9 (12%) respectively required pericardiectomy, 7 (9%) and 17 (23%) repeat pericardiocentesis (p less than 0.05), and 3 (4%) and 7 (9%) open surgical drainage. By 24 months, apart from the 16 who died from pericarditis, all but 3 patients (2%) had a favourable status.

Adolescent↗

PubMed1993

Isoflurane minimum alveolar concentration reduction by fentanyl.

BACKGROUND: Isoflurane is commonly combined with fentanyl during anesthesia. Because of hysteresis between plasma and effect site, bolus administration of fentanyl does not accurately describe the interaction between these drugs. The purpose of this study was to determine the MAC reduction of isoflurane by fentanyl when both drugs had reached steady biophase concentrations. METHODS: Seventy-seven patients were randomly allocated to receive either no fentanyl or fentanyl at several predetermined plasma concentrations. Fentanyl was administered using a computer-assisted continuous infusion device. Patients were also randomly allocated to receive a predetermined steady state end-tidal concentration of isoflurane. Blood samples for fentanyl concentration were taken at 10 min after initiation of the infusion and before and immediately after skin incision. A minimum of 20 min was allowed between the start of the fentanyl infusion and skin incision. The reduction in the MAC of isoflurane by the measured fentanyl concentration was calculated using a maximum likelihood solution to a logistic regression model. RESULTS: There was an initial steep reduction in the MAC of isoflurane by fentanyl, with 3 ng/ml resulting in a 63% MAC reduction. A ceiling effect was observed with 10 ng/ml providing only a further 19% reduction in MAC. A 50% decrease in MAC was produced by a fentanyl concentration of 1.67 ng/ml. CONCLUSIONS: Defining the MAC reduction of isoflurane by all the opioids allows their more rational administration with inhalational anesthetics and provides a comparison of their relative anesthetic potencies.

Adult↗

PubMed2003

Effect of pravastatin on LDL particle concentration as determined by NMR spectroscopy: a substudy of a randomized placebo controlled trial.

AIM: Recent data suggests that LDL particle concentration, as determined by Nuclear Magnetic Resonance (NMR) spectroscopy, may be associated with cardiovascular risk. We sought to determine the effect of randomization to pravastatin therapy on LDL particle concentration-NMR, among a primary prevention population. METHODS AND RESULTS: LDL particle concentration-NMR, LDL size-NMR, and standard chemical lipid parameters were measured at baseline and after 12 weeks among 500 individuals without overt coronary disease randomly allocated to pravastatin 40mg (n=256) or placebo (n=244). Randomization to pravastatin therapy caused a 19% reduction in median LDL particle concentration-NMR at 12 weeks, as compared to a 4.2% increase among those randomized to placebo (P<0.001 for pravastatin group compared to placebo). Pravastatin therapy caused a median 24.9% reduction in LDL cholesterol measured chemically compared to a 0.9% increase in the placebo group (P<0.001). Pravastatin therapy did not cause a significant change in median LDL size-NMR (0.5% increase in pravastatin group vs 0.0% in placebo group; P=0.25). The change in LDL particle concentration with pravastatin correlated inversely with baseline LDL size (r=-0.24; P<0.001) such that the largest reduction in LDL particle concentration-NMR was among those with the smallest LDL size-NMR at baseline (median% change =21.4% for tertile 1 of LDL size, 19.9% for tertile 2, and 16.5% for tertile 3; P=0.03). In contrast, pravastatin-induced changes in LDL cholesterol did not correlate with baseline LDL size-NMR (r=-0.05; P=0.47). CONCLUSION: Among individuals without overt hyperlipidemia or known coronary artery disease, randomized allocation to pravastatin (40mg) therapy for 12 weeks caused a reduction in LDL particle concentration-NMR, the magnitude of which was dependent on baseline LDL size-NMR.

Anticholesteremic Agents↗

PubMed2004

The UK Endovascular Aneurysm Repair (EVAR) trials: design, methodology and progress.

OBJECTIVES: The endovascular aneurysm repair (EVAR) trials aim to assess the efficacy of EVAR in the treatment of AAA in terms of mortality, quality of life, durability and cost-effectiveness. DESIGN: Male and female patients aged at least 60 years with an AAA diameter measuring at least 5.5 cm on a computed tomography (CT) scan are assessed for anatomical suitability for EVAR. Suitable patients are offered entry either into EVAR Trial 1 if they are considered fit for conventional open repair or EVAR Trial 2 if they are considered unfit. EVAR 1 randomly allocates patients to EVAR or open repair and EVAR 2 randomly allocates patients to EVAR with best medical treatment or best medical treatment alone. Target recruitment for EVAR Trials 1 and 2 is 900 and 280 patients, respectively. PROGRESS: Recruitment began in September 1999 and there are currently 40 UK centres participating in the trials. Monthly targets are being exceeded in EVAR Trial 1 with 1037 patients randomised by October 2003. EVAR Trial 2 is also meeting monthly targets with a total of 319 patients randomised. When recruitment closes in December 2003 patients will need to be followed for at least 1 year from their operation. Publication of full results for both trials is expected in mid 2005.

Aortic Aneurysm, Abdominal↗

PubMed2001

Impact of different gases and pneumoperitoneum pressures on tumor growth during laparoscopy in a rat model.

BACKGROUND: The influence on intraperitoneal tumor growth of the choice of gas and pneumoperitoneum pressure during laparoscopy is still unknown. This study compared tumor growth after laparoscopy with different gases and pneumoperitoneum pressures in an immunodeficient model. METHODS: In an initial experiment, 60 nude rats were randomly allocated to undergo laparoscopy at different pneumoperitoneum pressures (gasless, 4 mmHg, or 8 mm Hg.) In a second experiment, 23 nude rats were randomly allocated to undergo laparoscopy with different gases (carbon dioxide or helium). Surgery was carried out 7 days after intraperitoneal injection of IGR-OV1 cells. The rats were killed 7 days after surgery. Tumor growth was assessed by the weight of the omental metastasis. For statistical analysis, we used analysis of variance (ANOVA). RESULTS: Mean omental weight was similar for all groups, regardless of the pneumoperitoneum pressure (p = 0.86) or the type of gas (p = 0.80). CONCLUSION: Physical parameters of gas have a limited impact on tumor growth.

Animals↗

PubMed1992

The pain and discomfort experienced during orthodontic treatment: a randomized controlled clinical trial of two initial aligning arch wires.

A randomized controlled clinical trial was performed to compare the nature, prevalence, intensity, and duration of pain related to the use of a relatively recently developed superelastic arch wire and a more traditional multistranded steel arch wire. Other factors likely to influence the pain experience were also investigated. Forty-three subjects participated in the study, the pain response being assessed by each of the visual analogue scales, the questionnaires, and an analgesic consumption record. In 18 of the 43 subjects a standardized preliminary dental extraction procedure was used as a control. Subsequent to the random allocation of an initial arch wire in 43 patients, 22 of them underwent a second arch wire in the opposing arch, the wire again being determined by random allocation. It was found that the prevalence, intensity, and duration of pain after the insertion of the two types of wire was similar but much greater than in the postextraction control phase. The pain score peaked on the morning after the placement of the arch wire, lasting typically for 5 to 6 days. The pain and discomfort experienced after the insertion of the second arch wire was similar to that of the first, no conditioning response being evident. Overall a diurnal variation was found with a tendency to an increase in pain in the evenings and nights, although this did not greatly affect sleep. The pain response was found to be highly and consistently subjective, not related to the dental arch, crowding, sex, or social class; however, a statistically significant association was found between the age and the pain experienced.

Adolescent↗

PubMed1987

Do serotonin uptake inhibitors decrease smoking? Observations in a group of heavy drinkers.

Serotonin uptake inhibitors have been reported to alter several consummatory and drug self-administration behaviors in rats. These observations suggest important therapeutic applications in humans. While evaluating zimelidine and citalopram effects on ethanol intake, we also assessed smoking behavior. Five male heavy drinkers smoking 29.7 +/- 9.0 (mean +/- SD) cigarettes a day were randomly allocated to receive zimelidine (200 mg/day orally) or placebo in a double-blind crossover study. Another 17 male heavy drinkers smoking 21.1 +/- 14.3 (mean +/- SD) cigarettes a day were randomly allocated to receive citalopram (20 or 40 mg/day orally) or placebo in a double-blind crossover study. In both studies, subjects were not trying to modify their smoking or drinking and received no advice or other treatment to do so. Zimelidine had no effects on the number of cigarettes smoked (F1,4 = 1.80, not significant (NS]. Neither citalopram dose had an effect on smoking (citalopram 20 mg: F1,8 = 0.06, NS; citalopram 40 mg: F1,7 = 0.68, NS). Because intrasubject variation is small, this trial was of sufficient size to exclude with 99.99% confidence the possibility that these drugs decrease smoking behavior by 50%. Since serotonin uptake inhibitors can attenuate ethanol intake in humans, these drugs may have differential effects on consummatory behaviors.

Adult↗

PubMed2001

Methodology standards associated with quality reporting in clinical studies in pediatric surgery journals.

BACKGROUND/PURPOSE: Reports of clinical trials often lack adequate descriptions of design and analysis; recent attention has focused on improving this omission so readers can properly assess the strength of the findings and draw their own conclusions. Similar analysis of study design and methodologic standards associated with quality reporting has not been carried out for pediatric surgery journals. METHODS: All studies (n = 642) published in 1998 in Journal of Pediatric Surgery (JPS) and Pediatric Surgery International (PSI), were reviewed for demographic data and study design. The frequency of reporting of 11 basic elements of design and analysis was evaluated in randomized clinical trials (RCT), nonrandomized clinical trials (NRCT), and retrospective cohorts (RC) from JPS by consensus of 2 assessors. RESULTS: Of the 642 studies, 17% of articles (111 of 642) were classified as clinical studies. Sixty-three were comparative studies and consisted of RC (n = 48), NRCT (n = 12), and RCT (n = 3). Two-thirds of articles published were either case reports or case series (431 of 642), and 16% were basic science articles. Demographic analysis showed a wide range of topics addressed, 4 authors per article, and multiple country of origin of authors. More than 66% of all RCT in JPS reported on eligibility criteria, admission before allocation, random allocation, method of randomization, patients' blindness to treatment, treatment complications, statistical analyses, statistical methods, loss to follow-up, and statistical methods; 2 elements of design and analysis, however, were poorly reported: blind assessment of outcome (33%) and power (17%). CONCLUSIONS: There were few randomized, controlled trials in pediatric surgery journals, and further attention should be given to evaluate the causal factors. Nine elements of quality reporting were well reported; however, 2 others were poorly reported; this may improve if editors of pediatric surgical journals provide authors with guidelines on how to report clinical trial design and analysis.

Authorship↗

PubMed1989

A controlled trial of 3-month, 4-month, and 6-month regimens of chemotherapy for sputum-smear-negative pulmonary tuberculosis. Results at 5 years. Hong Kong Chest Service/Tuberculosis Research Centre, Madras/British Medical Research Council.

Of 1,710 Chinese patients with radiologically active pulmonary tuberculosis but with sputum negative for acid-fast bacilli on four or more initial microscopic examinations who were studied for 5 yr, 592 (35%) had one or more initial sputum cultures positive for Mycobacterium tuberculosis. These 592 patients were randomly allocated to receive streptomycin, isoniazid, rifampin, and pyrazinamide daily for 4 months or 3 times a week for either 4 or 6 months. The remaining 1,118 patients with all their initial cultures negative were randomly allocated to receive the same four drugs daily for 3 months or 3 times a week for either 3 or 4 months. There were no bacteriologic failures during chemotherapy, and the relapse rates for the 4-month regimens during the 5 yr were 2% in 293 patients with drug-susceptible cultures initially (95% confidence limits, 1 to 5%); 8% in 59 patients with cultures resistant to isoniazid, streptomycin, or both drugs, but susceptible to rifampin initially; and 4% in 325 patients with all their cultures negative initially (95% confidence limits, 1 to 7%). The combined relapse rate for the 3-month regimens was 7% in 709 patients with all their cultures negative initially (95% confidence limits, 5 to 9%). In Hong Kong, 4 months of chemotherapy is now used routinely in the treatment of patients with smear-negative pulmonary tuberculosis, whether their initial sputum cultures are positive or negative.

Adolescent↗

PubMed1989

Influence of maternal diet during lactation and use of formula feeds on development of atopic eczema in high risk infants.

OBJECTIVE: To examine the effects of maternal diet during lactation and the use of formula feeds on the development of atopic eczema in infants at risk. DESIGN: Mothers who planned to breast feed exclusively were randomly allocated to either a restricted diet (avoiding milk and other dairy products, eggs, fish, peanuts, and soybeans) or a diet without restrictions. Mothers who did not plan to breast feed were randomly allocated to using one of three formula feeds. SETTING: Child health centre in Canada. SUBJECTS: 97 Mothers who chose to breast feed and 124 mothers who did not. INTERVENTIONS: Restricted diet for 49 mothers who breast fed. Casein hydrolysate formula, soy milk formula, or cows' milk formula for infants not breast fed. MAIN OUTCOME MEASURE: Development of eczema in babies. RESULTS: Infants were followed up over 18 months and examined for eczema. Eczema was less common and milder in babies who were breast fed and whose mothers were on a restricted diet (11/49 (22%) v 21/48 (48%)). In infants fed casein hydrolysate, soy milk, or cows' milk 9/43 (21%), 26/41 (63%), and 28/40 (70%), respectively, developed atopic eczema. CONCLUSIONS: In families with a history of atopic disease [corrected] mothers who breast feed should avoid common allergenic foods during lactation. If they choose not to breast feed a hydrolysate formula should be used.

Bottle Feeding↗

PubMed1991

Effects of varying recall periods on reported food intakes.

A 32-item food frequency questionnaire was administered with different time periods over which intake frequencies were to be recalled. In replicate Studies 1 and 2, 154 students were randomly allocated to six recall periods, ranging from the "the past 3 days" through to "the past year" and "usual intake". Perceived "oftenness" of intake was estimated on seven-point ratings. In Study 3, 78 students were randomly allocated to five short recall periods, e.g. last weekend, the past 5 days. In addition to rating "oftenness", they estimated their frequencies of intake numerically. In the first two studies, recall period was related to "oftenness" ratings in three ways. Responses for some foods (mainly snacks) were unaffected by recall period; others (mainly staples) were monotonically related to the requested duration of the recall; and, for a third set of foods, periods greater than one month (including "usual intake") yielded equivalent ratings but these were greater frequencies than those associated with shorter recall periods. In Study 3, marked differences were seen between frequency ratings over "average" durations and those over recent periods of similar duration. Correlations between numerical frequency estimates and "oftenness" ratings were high. The implications of the results for uses of food frequency methodology in nutritional epidemiology are discussed.

Adult↗

PubMed2007

Influence of acute normovolaemic haemodilution on the dose-response relationship and time course of action of cisatracurium besylate.

BACKGROUND: Acute normovolaemic haemodilution (ANH) is an efficacious blood conservation strategy aiming at avoiding allogeneic blood transfusion. ANH was shown to increase the potency of vecuronium, atracurium, and rocuronium. The aim of our study was to investigate whether cisatracurium potency is altered with ANH. METHODS: Using the Relaxometer mechanomyograph, we compared cisatracurium dose-response relationship and time course of action in 60 patients randomly allocated to the ANH or control groups. Patients in each group were randomly allocated to receive one of three cisatracurium doses (30, 40, 50 microg kg(-1)) followed by a second supplemental dose to reach a total of 100 microg kg(-1). RESULTS: ANH did not result in a significant shift in cisatracurium log dose-probit dose-response curve. There was no significant difference in mean (95% confidence intervals) ED(50), ED(90), and ED(95) (effective doses required for 50, 90, and 95% first twitch depression) between the ANH group [29.5 (27-32), 50.4 (47.4-53.4), 58.7 (55.3-62) microg kg(-1)] and the control group [28.2 (25.3-31), 47.6 (44.9-50.3), 55.3 (52.5-58.1) microg kg(-1)], whereas there was no difference in mean (SD) Dur(25) and Dur(0.8) (time until 25% first twitch and 0.8 train-of-four ratio recoveries) between the ANH group [40.8 (5.9), 64.7 (8.4) min] and the control group [42.2 (7.6), 66.5 (10.7) min]. CONCLUSIONS: Our results demonstrated that unlike other previously reported neuromuscular blocking drugs, ANH did not alter cisatracurium potency. Thus, cisatracurium would be the neuromuscular blocking drug of choice in patients who undergo surgery with ANH, as no dose adjustments are required.

Adult↗

PubMed2001

Efficacy of a long-acting formulation of ivermectin against Psoroptes ovis (Hering, 1838) on cattle.

A study was conducted in cattle experimentally infested with Psoroptes ovis to compare the prophylactic control against P. ovis provided by a long-acting injectable formulation of ivermectin to that of a commercially available injectable formulation of doramectin. Thirty Holstein steers were used. Animals were allocated by restricted randomization based on Day 0 body weight, forming six replicates of five animals each. Within each replicate, one animal was randomly allocated to one of the following treatment groups, with ivermectin and doramectin administered subcutaneously where indicated: (1) untreated controls; (2) ivermectin long-acting injectable (LAI) 630 mcg/kg, 56 days before challenge; (3) ivermectin LAI 630 mcg/kg, 42 days before challenge; (4) ivermectin LAI 630 mcg/kg, 35 days before challenge; or (5) doramectin 200 mcg/kg, 35 days before challenge. Animals were housed in individual pens 1 week prior to treatment. All animals were experimentally infested with P. ovis mites in the area between the shoulders, on the same day. Live mites were counted in scrapings from mange lesions at 2 sites on each animal 14, 21 and 28 days after challenge. Live mites were found in 33, 67 and 83% of the untreated controls on each respective evaluation. No P. ovis mites were found in steers treated with ivermectin LAI. Those animals showed lower (P < 0.05) mite counts than untreated controls on evaluations conducted 21 and 28 days after challenge. These results indicate that the ivermectin long-acting injectable formulation prevents induced infestations by P. ovis for at least 56 days after treatment. Doramectin injectable formulation, used at 200 mcg/kg, did not have a prophylactic effect 35 days after treatment.

Animals↗

PubMed2004

European Nicotinamide Diabetes Intervention Trial (ENDIT): a randomised controlled trial of intervention before the onset of type 1 diabetes.

BACKGROUND: Results of studies in animals and human beings suggest that type 1 diabetes is preventable. Nicotinamide prevents autoimmune diabetes in animal models, possibly through inhibition of the DNA repair enzyme poly-ADP-ribose polymerase and prevention of beta-cell NAD depletion. We aimed to assess whether high dose nicotinamide prevents or delays clinical onset of diabetes in people with a first-degree family history of type 1 diabetes. METHOD: We did a randomised double-blind placebo-controlled trial of nicotinamide in 552 relatives with confirmed islet cell antibody (ICA) levels of 20 Juvenile Diabetes Federation (JDF) units or more, and a non-diabetic oral glucose tolerance test. Participants were recruited from 18 European countries, Canada, and the USA, and were randomly allocated oral modified release nicotinamide (1.2 g/m2) or placebo for 5 years. Random allocation was done with a pseudorandom number generator and we used size balanced blocks of four and stratified by age and national group. Primary outcome was development of diabetes, as defined by WHO criteria. Analysis was done on an intention-to-treat basis. FINDINGS: There was no difference in the development of diabetes between the treatment groups. Of 159 participants who developed diabetes in the course of the trial, 82 were taking nicotinamide and 77 were on placebo. The unadjusted hazard ratio for development of diabetes was 1.07 (95% CI 0.78-1.45; p=0.69), and the hazard ratio adjusted for age-at-entry, baseline glucose tolerance, and number of islet autoantibodies detected was 1.01 (0.73-1.38; p=0.97). Of 168 (30.4%) participants who withdrew from the trial, 83 were on placebo. The number of serious adverse events did not differ between treatment groups. Nicotinamide treatment did not affect growth in children or first-phase insulin secretion. INTERPRETATION: Large-scale controlled trials of interventions designed to prevent the onset of type 1 diabetes are feasible, but nicotinamide was ineffective at the dose we used.

Autoimmune Diseases↗

PubMed1995

Haemodynamics, cardiac conduction and pharmacokinetics of mibefradil (Ro 40-5967), a novel calcium antagonist.

OBJECTIVES: Mibefradil (Ro40-5967) is a chemically novel non-dihydropyridine calcium antagonist. In this phase II study we compared its acute and chronic effects on blood pressure, heart rate and atrioventricular conduction (electrocardiographic PQ interval) with those of verapamil and diltiazem. PATIENTS AND METHODS: After a 4-week placebo run-in, 18 patients with mild to moderate essential hypertension were given single doses of mibefradil (150 mg), slow-release (SR) verapamil (240 mg), diltiazem (240 mg) and placebo at weekly intervals; pharmacokinetics and the effects on blood pressure, heart rate and PQ interval were studied on four 10-h study days. Seventeen of the same patients subsequently underwent 4 weeks of treatment with either mibefradil (100 mg daily; n = 10) or verapamil SR (240 mg daily; n = 7), and on the last day, they attended a further 10-h study day. Two studies were conducted: an acute, single-dose, double-blind, randomly allocated, placebo-controlled, crossover study and a chronic, open-label, randomly allocated, parallel-group study. RESULTS: Mibefradil was well tolerated. In the acute study, the antihypertensive effect (difference from placebo) of mibefradil 150 mg was of slower onset than that of verapamil or diltiazem, but comparable blood pressure reductions had been achieved by 6 h. The mean +/- SD maximal PQ prolongation (difference from placebo) was 15.6 +/- 16.1 ms, compared with 44.0 +/- 22.6 ms for verapamil and 56.0 +/- 48.9 ms for diltiazem (P<0.05 mibefradil versus verapamil; P<0.01 mibefradil versus diltiazem). In the chronic study there were no significant differences during steady-state conditions between mibefradil at 100 mg and verapamil SR at 240 mg in their effects on blood pressure, PQ and heart rate. The mean +/- SD elimination half-life (t1/2) of mibefradil under steady-state conditions was 26.8 +/- 5.5 h (versus an apparent t1/2 of 16.9 +/- 11.1 h for verapamil SR, P<0.05). CONCLUSIONS: Mibefradil is a well-tolerated and efficacious antihypertensive agent well suited to single daily dosing because of its intrinsic long plasma half-life. The effects on both blood pressure and PQ interval are of more gradual onset than those of unmodified verapamil and diltiazem after single doses.

Adolescent↗