Controlled organocatalyzed d,l-lactide ring-opening polymerizations: synthesis of low molecular weight oligomers.

A systematic approach to the synthesis of organocatalyzed oligo(d,l-lactide) demonstrates that choice of initiator, catalytic ratio, and reaction time yields well-controlled oligomers. Ring-opening polymerization of d,l-lactide with the initiator α-methyl propargyl alcohol, a secondary alcohol, used in excess of 4-dimethylaminopyridine catalyst mitigates cyclicization, transesterification, and catalyst-initiated side reactions. This approach enables the design of uniform lactide oligomers for controlled release applications, such as delivery systems for drugs, prodrugs, and molecular sensors.

The value of image-guided intensity-modulated radiotherapy in challenging clinical settings.

OBJECTIVE: To illustrate the wider potential scope of image-guided intensity-modulated radiotherapy (IG-IMRT), outside of the "standard" indications for IMRT. METHODS: Nine challenging clinical cases were selected. All were treated with radical intent, although it was accepted that in several of the cases the probability of cure was low. IMRT alone was not adequate owing to the close proximity of the target to organs at risk, the risk of geographical miss, or the need to tighten planning margins, making image-guided radiotherapy an essential integral part of the treatment. Discrepancies between the initial planning scan and the daily on-treatment megavoltage CT were recorded for each case. The three-dimensional displacement was compared with the margin used to create the planning target volume (PTV). RESULTS: All but one patient achieved local control. Three patients developed metastatic disease but benefited from good local palliation; two have since died. A further patient died of an unrelated condition. Four patients are alive and well. Toxicity was low in all cases. Without daily image guidance, the PTV margin would have been insufficient to ensure complete coverage in 49% of fractions. It was inadequate by >3 mm in 19% of fractions, and by >5 mm in 9%. CONCLUSION: IG-IMRT ensures accurate dose delivery to treat the target and avoid critical structures, acting as daily quality assurance for the delivery of complex IMRT plans. These patients could not have been adequately treated without image guidance. ADVANCES IN KNOWLEDGE: IG-IMRT can offer improved outcomes in less common clinical situations, where conventional techniques would provide suboptimal treatment.

Practical aspects of implementation of helical tomotherapy for intensity-modulated and image-guided radiotherapy.

AIMS: Image-guided radiotherapy (IGRT) and intensity-modulated radiotherapy (IMRT) represent two important technical developments that will probably improve patient outcome. Helical tomotherapy, provided by the TomoTherapy HiArt system, provides an elegant integrated solution providing both technologies, although others are available. Here we report our experience of clinical implementation of daily online IGRT and IMRT using helical tomotherapy. MATERIALS AND METHODS: Methods were needed to select patients who would probably benefit. Machine-specific commissioning, a quality assurance programme and patient-specific delivery quality assurance were also needed. The planning target volume dose was prescribed as the median dose, with the added criterion that the 95% isodose should cover 99% of the target volume. Although back-up plans, for delivery on conventional linear accelerators, were initially prepared, this practice was abandoned because they were used very rarely. RESULTS: In the first 12 months, 114 patients were accepted for treatment, and 3343 fractions delivered. New starts averaged 2.6 per week, with an average of 17.5 fractions treated per day, and the total number capped at 22. This has subsequently been raised to 24. Of the first 100 patients, 96 were treated with radical intent. Five were considered to have been untreatable on our standard equipment. IGRT is radiographer led and all patients were imaged daily, with positional correction made before treatment, using an action level of 1mm. A formal training programme was developed and implemented before installation. The in-room time fell significantly during the year, reflecting increasing experience and a software upgrade. More recently, after a couch upgrade in April 2009, the mean in-room time fell to 18.6 min. CONCLUSIONS: Successful implementation of tomotherapy was the result of careful planning and effective teamwork. Treatment, including daily image guidance, positional correction and intensity-modulated delivery, is fast and efficient, and can be integrated into routine service. This should encourage the adoption of these technologies.

Pulmonary echinococcosis with chest wall involvement in a patient with no apparent risk factors.

Pulmonary hydatid disease is rare in the U.K., and chest wall involvement has to our knowledge not previously been described in this country. We report the case of a 72-year-old man who was found to have a left upper lobe opacity on his chest radiograph. He declined further investigation at the time, but 2 years later developed a palpable mass over his left lateral chest wall. Fine-needle aspiration-biopsy of this mass revealed the diagnosis of pulmonary hydatid disease. Despite thorough questioning, no risk factor could be identified for the development of the disease. Hydatid disease should be remembered as a rare cause of mass lesions identified on chest radiographs even in non-endemic regions. Spread to the chest wall may mimic malignancy.

Two cases of fatal zopiclone overdose.

Two cases of death due to the ingestion of zopiclone are presented. Quantitative determinations of zopiclone yielded 1.4-3.9 mg/L in the blood, 0.81 and 8.7 mg/kg in the liver, and 13.5 and 133 mg in the stomach contents. Drug concentrations were interpreted relative to the case findings, published data, and a limited evaluation of therapeutic concentrations found in two cases of therapeutic zopiclone use. Zopiclone was extracted from buffered blood or digested liver or both with n-butyl chloride and analyzed by high-performance liquid chromatography with ultraviolet detection. Liver samples were digested at pH 7 to avoid zopiclone decomposition.