Radiosynthesis and in vivo evaluation of a ¹8F-labelled styryl-benzoxazole derivative for ß-amyloid targeting.

The formation of ß-amyloid deposits is considered a histopathological feature of Alzheimer's disease (AD). In vivo molecular imaging by means of amyloid-avid radiotracers will allow for an early and conclusive diagnostic of AD. Herein, we describe the radiosynthesis of the radiofluorinated styryl benzoxazole derivative [¹8F]-[2-[N-methyl-N-(2'-fluoroethyl)-4'-aminostyryl]benzoxazole] ([¹8F]-1) and its pre-clinical evaluation, including metabolic and biodistribution studies in male Wistar rats. The in vivo biological evaluation of [¹8F]-1 showed that this new radiotracer has a moderate brain uptake with a slow brain washout and a poor in vivo stability.

Synthesis of neurotensin(8-13)-phosphopeptide heterodimers via click chemistry.

Two neurotensin(8-13)-containing peptide heterodimers were prepared via copper(I)-mediated click chemistry. The resulting peptide dimers could be obtained in 28-31% yield after HPLC purification. Neurotensin(8-13)-containing peptide dimers were used in an in vitro binding assay to determine binding affinity towards the neurotensin receptor-1 (NTR1). The determined IC(50) values of 8.3 microM and 0.7 microM indicate only very low binding affinity of the neurotensin(8-13)-containing peptide heterodimers towards the NTR1.

Carbon-11 labeling chemistry based upon [11C]methyl iodide.

Radiochemistry with the short-lived positron emitter 11C (half-life 20.38 min) represents special challenges in terms of synthesis time and labeling techniques. The recent developments in 11C radiochemistry have steadily expanded the number of 11C labeled compounds. This chapter addresses selected chemical and technical aspects of 11C chemistry based on the readily available labeling precursors [11 C]methyl iodide and, to a lesser extent, [11C]methyl triflate. Special emphasis is placed on heteroatom methylation reactions and 11C-C bond formations.

Synthesis and biological evaluation of silylated mixed-ligand 99mTc complexes with the [PNS/S] donor atom set.

New oxotechnetium complexes of general formula [99mTc(O)(PNS)(S(CH2)nOSiR3)] (4-6) were synthesized by direct reduction of [99mTcO4]- with stannous chloride, in the presence of the tridentate heterofunctionalized phosphine H2PNS and of the monodentate silylated thiols [HS(CH2)nOSiR3] (n = 2, R = Ph (1); n = 3, R = Ph (2); n = 3, R = Et (3)). The mixed-ligand rhenium and technetium complexes of general formula [M(O)(PNS)(S(CH2)nOH)] (n = 2: M = 99mTc, (7), M = Re, (7a); n = 3: M = 99mTc, (8), M = Re, (8a)) were also prepared. All the 99mTc complexes were obtained with high radiochemical purity (> 95%), after purification by HPLC, and were characterized by comparison of their HPLC profiles with the ones obtained for the corresponding Re compounds. The silylated compounds 4-6 are stable in phosphate saline buffer (PBS) pH 7.4, rat plasma, human serum and whole blood, and do not bind to plasmatic proteins, and also do not challenge with glutathione. The biological behavior of [99mTc(O)(PNS)(S(CH2)nOH)] (7, 8) and [99mTc(O)(PNS)(S(CH2)nOSiR3)] (4-6) was studied. The effect of the pH on the cleavage of the O-Si bond in complexes 4-6 was also evaluated.

[Corrective interventions for malunited fractures of the distal end of the forearm. Indications, choice of procedure, results]. / Korrektureingriffe nach in Fehlstellung verheilten Brüchen am distalen Unterarmende. Indikation, Verfahrenswahl, Ergebnisse.

Malunion, non-union, as well as painful ligamentous joint instability following fractures to the distal forearm may seriously compromise the function of a hand. Forty-seven surgically treated cases, thirty-nine of which were followed up, are presented in order to point out the problems of such lesions. Retrospective evaluation of the lesion is absolutely mandatory, as it often dates back to childhood. Management should take clinical findings as well as the patient's functional demands on his hands into consideration, but without overestimating therapeutic potentials.

[Results of angled plated osteosynthesis in per- and subtrochanteric fractures in the elderly]. / Ergebnisse nach Winkelplattenosteosynthese der per- und subtrochantären Brüche beim alten Menschen.

From 1/86 to 12/89 62 old patients (average age: 82.6) with intertrochanteric and subtrochanteric fractures underwent surgery by using angeled plates. The postoperative course showed complications in 32.2%, while only 1 patient died. In 3 of 5 cases with dislocation of the angeled plate re-osteosynthesis was performed. 4 other complications (2x haematoma, 2x wound dehiscence) needed further surgery. During the first three months 3 other dislocations occurred. In two cases re-osteosynthesis was carried out. Due to these results and the high rate of complications we are of the opinion that the indication for the use of the angeled plate osteosynthesis in old patients has to be limited in favor of other methods like the dynamic hip screw or total hip replacement.