Shortening the preparation time of the single prolonged breath-hold for radiotherapy sessions

Objective: Single prolonged breath-holds of >5 min can be obtained in cancer patients. Currently, however, the preparation time in each radiotherapy session is a practical limitation for clinical adoption of this new technique. Here, we show by how much our original preparation time can be shortened without unduly compromising breath-hold duration. Methods: 44 healthy subjects performed single prolonged breath-holds from 60% O2 and mechanically induced hypocapnia. We tested the effect on breath-hold duration of shortening preparation time (the durations of acclimatization, hyperventilation and hypocapnia) by changing these durations and or ventilator settings. Results: Mean original breath-hold duration was 6.5 ± 0.2 (standard error) min. The total original preparation time (from connecting the facemask to the start of the breath-hold) was 26 ± 1 min. After shortening the hypocapnia duration from 16 to 5 min, mean breath-hold duration was still 6.1 ± 0.2 min (ns vs the original). After abolishing the acclimatization and shortening the hypocapnia to 1 min (a total preparation time now of 9 ± 1 min), a mean breath-hold duration of >5 min was still possible (now significantly shortened to 5.2 ± 0.6 min, p < 0.001). After shorter and more vigorous hyperventilation (lasting 2.7 ± 0.3 min) and shorter hypocapnia (lasting 43 ± 4 s), a mean breath-hold duration of >5 min (5.3 ± 0.2 min, p < 0.05) was still possible. Here, the final total preparation time was 3.5 ± 0.3 min. Conclusions: These improvements may facilitate adoption of the single prolonged breath-hold for a range of thoracic and abdominal radiotherapies especially involving hypofractionation. Advances in knowledge: Multiple short breath-holds improve radiotherapy for thoracic and abdominal cancers. Further improvement may occur by adopting the single prolonged breath-hold of >5 min. One limitation to clinical adoption is its long preparation time. We show here how to reduce the mean preparation time from 26 to 3.5 min without compromising breath-hold duration

Catalysed stereodivergent hydrosilylation with Onium Salts stabilised M(0) nanocatalysts prepared in scCO2

M(0) nanocatalysts stabilised in Onium Salt were synthesised using an original preparation and their effectiveness in catalysing the challenging selective sterodivergent alkyne hydrosilylation reaction was studied.

A New Approach to the Synthesis of Chiral Blocks for Cyclopentanoids

A microreview is presented of the development by the authors of the original preparation of enantiomerically pure cyclopentane blocks from the racemic [2+2]-cycloadducts of 1,3-cyclopentadiene and its derivatives with dichloroketene.

The oldest fossil strepsipteran larva (Insecta: Strepsiptera) from the Geisel Valley, Germany (Eocene)

The only known fossil strepsipteran first-instar larva from Eocene brown coal is re-examined and redescribed, and photographs together with a detailed interpretative illustration are presented. The original preparation of the minute larva in a 1-mm-thick piece of brown coal of the Geisel valley precludes a detailed examination. After remounting, additional details of the larva are recognisable. A cladistic analysis of 60 morphological characters of 24 recent first-instar strepsipteran larva and the fossil larva confirm the placement in Strepsiptera and in Stylopidia with good support. A placement in Myrmecolacidae or even in the recent genus Stichotrema is rejected. Thus, Pseudococcites Haupt, 1950 comb.rev. is re-established and †Pseudococcites eocaenicus is moved to Stylopidia as incertae sedis.

Helical Phenanthrenes, Part 5. Synthesis of Pentahelicene-7,8-dione via Intramolecular Benzoin Condensation

The intramolecular benzoin condensation of [1,1'-binaphthyl]-2,2'-dicarbaldehyde (5), followed by oxidation with air, provides a new synthesis of (MP)-pentahelicene-7,8-dione (1). With reference to the original preparation of this quinone via acyloin condensation, its present yield (73% for the ring-closing step) is considerably increased.

Improved Epoxidation Methodology for Synthesis of the Highly Selective β2-Adrenoceptor Antagonist ICI 118551 [erythro (±)-3-Isopropylamino-1-(7-methylindan-4-yloxy)butan-2-ol]

In this communication we describe a much improved methodology for the synthesis of the selective β2-adrenoceptor antagonist ICI 118551 (1), a procedure which overcomes capricious fractional crystallization and epoxidation methodologies described for its original preparation. Our approach involving a bromohydrin precursor to the key epoxide intermediate (7) yielded an 85 : 15 mixture of the in threo/erythro isomers of (7) which could be conveniently separated by flash chromatography on amine-pretreated silica. This new approach proved much more successful than attempts to separate the precursor alkene isomers (6) by fractional crystallization as described in the original patent literature. The product (1) obtained by using our methodology was found to have identical pharmacological properties to authentic ICI 118551 when tested both in vitro and in vivo.