Evaluation of strained alkynes for Cu-free click reaction in live mice.

INTRODUCTION: We report on our evaluation of the strain-promoted cyclooctyne-azide cycloaddition reaction for use in tumor pretargeting, comprising a side-by-side comparison of probes 1-3 bearing three distinct cyclooctyne moieties based respectively on the 1st and 2nd generation difluorinated cyclooctyne and the 1st generation dibenzocyclooctyne. METHODS: The probes were synthesized and labeled with (177)Lu with high yields. The probe stability and reactivity towards azides were evaluated in PBS and mouse serum, and their blood clearance, biodistribution and in vivo reactivity were evaluated in tumor-free mice. RESULTS: In serum the three probes exhibited sufficient stability for a pretargeting application with half-lives of 12-19h. In PBS, probes 2 and 3 were more reactive towards azido-conjugated Rituximab (Rtx-N3) than 1, but in contrast to 1, their reactivity decreased in mouse serum and mouse serum albumin solutions, as a result of covalent and non-covalent interactions with albumin. Biodistribution data confirmed the interactions with serum proteins in circulation: (177)Lu-1 showed a fast elimination from blood (t1/2,ß = 0.31h), while (177)Lu-2 and (177)Lu-3 were retained in blood for longer periods of time (t1/2,ß = 1.08 and 3.58h, respectively). Dual isotope biodistribution experiments assessing the reaction between (125)I-Rtx-N3 and (177)Lu-1-3 in circulation in mice showed a very limited retention of 2 and 3 in blood rich organs, indicating a minimal reactivity, while no such retention was observed for 1. CONCLUSION: The low reactivity of the studied cyclooctynes, and their serum interactions preclude their use at the low in vivo concentrations typical for pretargeting applications.

Synthesis, in vitro and in vivo evaluation of radiolabeled nanoparticles.

Recent advances in the field of nanomedicine offer the promise of better diagnostic and therapeutic options. Synthetic chemists are making strides in developing nanoparticle constructs that can be used as platforms for attaching different functionalities for the purposes of molecular imaging and targeted drug delivery. As new nanoparticles are developed, it is imperative to evaluate their biological effectiveness by in vitro and in vivo screening techniques. While the in vitro results give insight into the cellular structure and function at sub-cellular level, the in vivo and ex vivo data give vital information about the pharmacokinetics of these novel particles, along with their ability to reach the desired target. This three-way information is pertinent to developing effective drugs and imaging probes for targeting key cancer/inflammation biomarkers such as the alphavbeta3 integrin. Labeling nanoparticles with positron emitting radionuclides can speed up this evaluation. In fact, small animal Positron Emission Tomography (PET) scanners allow researchers to quantitatively image the uptake of candidate nanocarriers at the target site with high sensitivity. In addition to conventional ex vivo biodistribution techniques, the pharmacokinetic profile of new nanomaterials with potential medical application can be obtained with dynamic and/or longitudinal PET studies on a relatively small number of laboratory animals. This article will focus on some of the approaches to label nanoparticles with positron emitting radionuclides along with in vitro and in vivo protocols that have been optimized and are being used for evaluating nanoparticles.

Experience with a small animal hyperthermia ultrasound system (SAHUS): report on 83 tumours.

An external local ultrasound (US) system was developed to induce controlled hyperthermia of subcutaneously implanted tumours in small animals (e.g., mice and rats). It was designed to be compatible with a small animal positron emission tomography scanner (microPET) to facilitate studies of hyperthermia-induced tumour re-oxygenation using a PET radiopharmaceutical, but it is applicable for any small animal study requiring controlled heating. The system consists of an acrylic applicator bed with up to four independent 5 MHz planar disc US transducers of 1 cm in diameter, a four-channel radiofrequency (RF) generator, a multiple thermocouple thermometry unit, and a personal computer with custom monitoring and controlling software. Although the system presented here was developed to target tumours of up to 1 cm in diameter, the applicator design allows for different piezoelectric transducers to be exchanged and operated within the 3.5-6.5 MHz band to target different tumour sizes. Temperature feedback control software was developed on the basis of a proportional-integral-derivative (PID) approach when the measured temperatures were within a selectable temperature band about the target temperature. Outside this band, an on/off control action was applied. Perfused tissue-mimicking phantom experiments were performed to determine optimum controller gain constants, which were later employed successfully in animal experiments. The performance of the SAHUS (small animal hyperthermia ultrasound system) was tested using several tumour types grown in thighs of female nude (nu/nu) mice. To date, the system has successfully treated 83 tumours to target temperatures in the range of 41-43 degrees C for periods of 65 min on average.

99mTc-labeling experiments on CCK(4) by a direct method.

99mTc-labeling studies have been performed on CCK(4) fragment of cholecystokinin, starting from 99mTc-pertechnetate, by using tin(II)pyrophosphate or tin(II)gluconate as reducing agents, together with NaBH(4) acting as a stabilizing agent of tin(II). Gluconate has been used as exchange ligand in the carrier added experiments and in the syntheses of 99Tc-CCK(4) and Re-CCK(4) complexes to be able to reproduce at macroscopic level the same chemical reactions occurring at non carrier added conditions. 99mTc-labeling yields higher than 95% have been achieved depending on Sn(II) concentration, CCK(4)/gluconate ratio, reaction time and applied temperature. The species produced with 99mTc, 99Tc, and cold rhenium nuclides have been compared by means of HPLC measurements, which showed similar retention times and thus probably the same species in the three situations.

PAcM-AN: poly (N-acryloylmorpholine)-conjugated antisense oligonucleotides.

A new amphiphilic, high-molecular weight poly (N-acryloylmorpholine) (PAcM) polymer has been used to be linked to oligonucleotide chains through a liquid-phase stepwise synthesis. This new conjugate has been investigated for its melting property, nuclease stability and capacity to elicit RNase H activity. Its antisense activity against an HIV-1 target has been also evaluated.

[Simultaneous bilateral traumatic dislocation of the hip. Report of a case (author's transl)]. / Luxation traumatique bilatérale et simultanée de la hanche. A propos d'un cas de double luxation iliaque.

A case of simultaneous bilateral traumatic dislocation of the hip is reported. A review of the literature shows that this lesion is rare and impressive but that its treatment is not particularly difficult.