Improving medication compliance: a randomised clinical trial.

A medical monitor which recorded the date and hour each time a medicine bottle was opened was used to evaluate a programme for improving patients'' compliance with their treatment. Eighty-two patients with glaucoma who had been prescribed pilocarpine eye drops three times daily to prevent visual loss were randomised into two groups. Both groups used the medication monitor during two 20-day periods, but before the second period the experimental group were given an education and tailoring programme in an attempt to improve their compliance. Nine patients missed the second treatment period and were excluded from the analysis. The patients in the experimental group showed significantly improved compliance when compared with the control group. The numbers of missed doses were reduced by about half, as was the proportion of time that exceeded the eight-hour dose intervals. Follow-up studies are needed to determine how long the improved compliance persists, but anyone considering setting up an education and tailoring programme should recognise the extent to which therapeutic efforts are wasted because of non-compliance.     

Compartmentation of uracil in Euglena gracilis.

Compartmentation of uracil in the flagellate Euglena gracilis was studied by tracer-kinetic experiments. Lag times in the equilibration of exogenously given and intracellularly present uracil before linear labeling of catabolic and anabolic products was determined to estimate the size of its metabolically active pool. This pool operates in the incorporation and degradation of uracil. There were the same lag times in forming both final products when measured in parallel and when measured after preloading with pyrimidines, in different cell strains, and under various environmental conditions. The amount of the metabolically active uracil pool, estimated as 11 pmol/10(7) heterotrophically growing cells, decreased to almost zero during light-induced RNA synthesis and could be changed by preloading with uracil or thymine. Besides this metabolic pool, cells may contain large amounts of uracil in a membrane-enclosed storage compartment (up to 12 nmol/10(7) cells). This is metabolically inert, but may be mobilized by nitrogen-carbon starvation. The role of uracil compartmentation in this metabolically flexible organism is discussed.     

Occurrence of norspermine in Euglena gracilis.

A series of fluorescent probes which locate a graded series of depths from the surface to the centre of the lipid bilayer have been used to measure the fluidity gradient in liposomes and natural membranes. In dioleoyl phosphatidylcholine liposomes and in cells which have a high content of unsaturated phospholipids, a region of high microviscosity is detected near the cis double bond/s. The significance of this phenomenon is discussed in terms of the penetration and lateral movement of membrane protein.     

Why we need a clinical trial for vitamin K.

Vitamin K is given to many babies born in the United Kingdom, but we still do not know if it has substantial hazards. Because the population exposed to vitamin K is very large even quite small hazards would involve many adverse events. It is therefore important to be able to put reasonably close bounds on the potential damage that vitamin K prophylaxis could cause. Past research has not allowed us to do this but a large randomised controlled clinical trial of vitamin K against no vitamin K, enrolling only infants at low risk of haemorrhagic disease, would do so. There is no question that vitamin K is a useful treatment in babies at highest risk of haemorrhagic disease: the question is whether the trend towards use of vitamin K in lower risk babies should be encouraged.     

Purification of Rhodotorula gracilis D-amino acid oxidase.

A protocol is presented for preparing Rhodotorula gracilis D-amino acid oxidase in homogeneous form and in high yield in 3 to 4 days. The method takes advantage of (a) cell rupture by alternate freeze-thawing, (b) use of DEAE-Sepharose to bind contaminants, and (c) enzyme binding to a Mono S column. The D-amino acid oxidase isolated by this means has the same spectral and catalytic properties as the enzyme previously obtained, and possesses improved long-term stability.     

Minimally invasive harvest of the gracilis muscle.

Acceptance of minimally invasive plastic surgery has been predicated on decreasing morbidity while maintaining the quality and costs of outcomes. The major patient complaint about the gracilis muscle donor site has almost solely been related to the length of the thigh scar, and thus would appear to be an ideal indication for outcome improvement using minimally invasive techniques. A method of endoscopically assisted gracilis muscle harvest, therefore, was developed, starting with a transverse incision just proximal to the knee to identify the gracilis tendon. This endoscopic port allows retrograde subfascial dissection of the muscle and precise identification of its anatomic course, whereupon a small proximal medial thigh incision can be made secondarily for direct access to the vascular pedicle. This variation has now been used successfully in 10 patients. The mean proximal thigh scar length was 8.30 +/- 0.74 (SD) cm, and total surgical scars measured 11.84 +/- 0.95 cm, compared with 27.73 +/- 9.55 cm for 16 patients for whom an open method had been used. This diminished scar length was a statistically significant improvement (p < 0.05), verifying the value of the surgical endoscope as an adjunct for harvest of the gracilis muscle as a free flap.     

Two-stage clinical trial stopping rules

Two-stage stopping rules for clinical trials are considered. The nominal significance level needed for the second-stage test, for any choice of first-stage significance level, is derived for rules with overall significance levels of .01 and .05 and for studies with either half or two-thirds of the patients analyzed in the first stage. A graphical demonstration is given of the inherent tradeoff between power and expected sample size (or probability of early termination). A specific rule, intermediate to those advocated by Pocock (1977, Biometrika 64, 191-199) and O'Brien and Fleming (1979, Biometrics 5, 549-556), is recommended.