Near-thorough QT study as part of a first-in-man study

Detailed electrocardiographic (ECG) support was provided to a first-in-man, single-ascending-dose study that included 6 cohorts of 8 male volunteers each. In each cohort, 6 and 2 subjects received active compound and placebo, respectively. Long-term 12-lead ECGs were obtained on baseline day -1, dosing day 1, and day 2. Automatic QT-interval measurements were made at 63 time points (28 at baseline and 35 on treatment). Based on QT/RR distribution, 20% of measurements were visually verified. Baseline-corrected time-matched DeltaQTc values were obtained at 35 postdose time points. Placebo subjects of all cohorts were pooled. When 2 cohorts of the lowest, middle, and highest doses were pooled (12 subjects per active treatment group), the spreads of placebo-corrected DeltaDeltaQTc values were within the regulatory requirements (single-sided 95% confidence interval <10 milliseconds) at all time points. Thus, this ECG support of the first-in-man study provided data of regulatory acceptable accuracy at a small fraction of the cost of a full thorough QT study.     

Asthma: a provincial study

To identify factors contributing to increased mortality and morbidity we prospectively evaluated 200 consecutive adult (greater than 17 years) asthmatic presentations (105 patients) referred to Gisborne Hospital over a 28 month period between 1985 and 1987 using a modified protocol adapted from previous national studies. In the moderate asthmatic group (113 presentations, 56%), 6% failed to use beta agonists prior to admission and 43% were not on regular steroid inhaler therapy. No patient had a crisis plan although 45 (22.5%) had received oral steroid therapy before admission. Poor drug compliance was twice as common in the Maori. Fifty-eight percent of patients were on regular long term oral theophylline whereas 48 (43%) patients with moderate and severe asthma were not on corticosteroid inhalers. We conclude that patient education and more liberal use of steroid inhalers have the greatest potential for improving morbidity and mortality.     

Tigecycline: a case study

The emergence of pathogenic bacteria resistant to virtually all available antibacterial agents at present has caused consternation among medical professionals, but has only intermittently raised concern among the public. This has led to a transient resurgence of interest in studying the mechanisms of resistance and in discovering and developing new antibacterial agents, but successes in the development of novel antibacterial agents have been few and far between. Although it has been known since the discovery of the tetracyclines that they are inhibitors of protein synthesis, there has been considerable recent progress on elucidating the mechanisms of action of the tetracyclines and in the enhanced understanding of the mechanisms of tetracycline resistance. In this case study, the authors discuss the discovery and development of a new class of antibacterials, which were derived from the tetracyclines, namely the glycylcyclines. This has resulted in the introduction of a new agent, tigecycline, to clinical practice. The glycylcyclines restore the antibacterial activity to levels of the earlier tetracyclines when they were first introduced, by overcoming the two major tetracycline-resistance mechanisms of efflux and ribosome protection, which promises to have a high degree of clinical utility.     

Cellactose a co-processed excipient: a comparison study

This article describes the differences in compaction properties between microcrystalline cellulose (MCC) and alpha-lactose monohydrate physical mixture, and microcrystalline cellulose co-processed with alpha-lactose monohydrate (Cellactose). The different compaction parameters are not only compared for the pure materials but also for the lubricated powders with magnesium stearate. Magnesium stearate does not facilitate the densification of either the physical mixture or Cellactose during compaction. The difference in tablet relaxation of the physical mixture and Cellactose indicates that the negative effect of the lubricant on the interparticle bonding of Cellactose particles is smaller than the physical mixture particles because after compaction, the structure in the Cellactose tablet is completely different from that in the physical mixture tablet. However, a larger increase in tablet relaxation at a high compression speed was found for both Cellactose and the physical mixture at different lubricant concentrations: 1.0% and 0.0%. Accordingly, the decrease in tablet strength was larger for the physical mixture tablets than for the Cellactose tablets when lubrication was applied. The examination of the tablet strengths of tablets compressed from physical mixtures of different ratios of alpha-lactose monohydrate and MCC proved the positive effect of cellulose on the tensile strength of tablets. Co-processing of MCC with alpha-lactose monohydrate showed extra contribution on the tablet strength of a physical mixture with the same mixing ratio. This extra contribution of Cellactose was attributed only to the interfacial attraction of the particles.     

Tourette syndrome: a follow-up study

We describe a long-term follow-up study (1-15 years) of 33 patients with Tourette syndrome who were treated with pimozide (2-18 mg), haloperidol (2-15 mg), or no drugs. Both drugs produced comparable relief of symptoms at follow up; however, significantly more patients on haloperidol (eight of 17), compared with those on pimozide (one of 13), discontinued treatment (p less than or equal to 0.05). Haloperidol produced significantly more acute dyskinesias/dystonias than pimozide (p less than or equal to 0.03); otherwise, the adverse effect profile was similar for the two drugs. In particular, we found no increased incidence of ECG abnormalities in patients treated with pimozide. A prospective, randomized, double-blind crossover trial is required to determine whether there are significant differences in efficacy between pimozide and haloperidol in treatment of Tourette's disorder.     

How to start a neuroimaging study

In order to help researchers understand how to start a neuroimaging study, several tips are described in this paper. These include 1) Choice of an imaging modality, 2) Statistical method, and 3) Interpretation of the results. 1) There are several imaging modalities available in clinical research. Advantages and disadvantages of each modality are described. 2) Statistical Parametric Mapping, which is the most common statistical software for neuroimaging analysis, is described in terms of parameter setting in normalization and level of significance. 3) In the discussion section, the region which shows a significant difference between patients and normal controls should be discussed in relation to the neurophysiology of the disease, making reference to previous reports from neuroimaging studies in normal controls, lesion studies and animal studies. A typical pattern of discussion is described.     

Caesarean section: a national study

Although the use of caesarean section (CS) continues to be debated, the demographic characteristics of the affected population have received little attention. This paper shows that in New Zealand during 1983-84, a CS was performed on 9.6% of delivered women between the ages of 15-44. The rate increased with maternal age (p less than 0.01), and was highest for 'single' women (11.3/100) and Pacific Island women aged 35-44 (21/100). There was a significantly (p less than 0.05) high rate in the Auckland and South Otago hospital board districts, but a low rate (p less than 0.05) in the Ashburton, Nelson, Canterbury, Southland, Taumaranui, Waiapu, Wairarapa, Wanganui, and Wellington board districts. The rate was also high (p less than 0.01) in the principal teaching hospitals. Long labour (15.2%), malposition and malpresentation of the fetus (14.7%) were the leading reasons for performing a CS. The paucity of national data on a number of other highly relevant birth and maternal factors hinders the further definition of the epidemiological patterns of CS in New Zealand.     

Anandamide vehicles: a comparative study

Among the studies that investigate the vasorelaxation induced by anandamide, one of the most frequent differences is the use of distinct solvents that could modify vascular function and explain the controversial results described. The aims of this study were: to evaluate the influence of different cannabinoid vehicles in vascular function of rat aorta, and to compare the vasorelaxation induced by anandamide dissolved in different vehicles. Vehicles were: ethanol (70%), Tween 80/ethanol (2:1 and 1:1), 1:1:18 (Tween 80/ethanol/saline) and dimethylsulphoxide (DMSO) 0.5%. All the vehicles tested, except DMSO 0.5%, modified the vascular and/or the endothelial function in rat aorta rings. Anandamide caused a time- and concentration-dependent vasorelaxation in all the experimental groups except in ethanol group, but the mechanisms involved in its vasorelaxation appear to be different depending on the vehicle used. The results obtained with vehicles containing Tween 80 suggest a non-endothelial component in the vasorelaxation caused by anandamide, while those obtained with DMSO at 0.5% suggest an endothelial component in this vasorelaxation.