Cochrane reviews on the benefits/risks of fluoride toothpastes.

This concise review presents two Cochrane Reviews undertaken to determine: (1) the relative effectiveness of fluoride toothpastes of different concentrations in preventing dental caries in children and adolescents; and (2) the relationship between the use of topical fluorides in young children and their risk of developing dental fluorosis. To determine the relative effectiveness of fluoride toothpastes of different concentrations, we undertook a network meta-analysis utilizing both direct and indirect comparisons from randomized controlled trials (RCTs). The review examining fluorosis included evidence from experimental and observational studies. The findings of the reviews confirm the benefits of using fluoride toothpaste, when compared with placebo, in preventing caries in children and adolescents, but only significantly for fluoride concentrations of 1000 ppm and above. The relative caries-preventive effects of fluoride toothpastes of different concentrations increase with higher fluoride concentration. However, there is weak, unreliable evidence that starting the use of fluoride toothpaste in children under 12 months of age may be associated with an increased risk of fluorosis. The decision of what fluoride levels to use for children under 6 years should be balanced between the risk of developing dental caries and that of mild fluorosis.

Structure-distribution relationships for metal-labeled myocardial imaging agents: comparison of a series of cationic gallium (III) complexes with hexadentate bis(salicylaldimine) ligands.

A series of 10 cationic gallium(III) complexes with hexadentate bis(salicylaldimine) ligands were synthesized, characterized, radiolabeled with 67Ga, and screened in a rat model to assess their potential as 68Ga radiopharmaceuticals for imaging the heart with positron emission tomography. The tris(salicylaldimine) ligand precursors were synthesized by condensation of either bis(3-aminopropyl)ethylenediamine (BAPEN) or bis(2,2-dimethyl-3-aminopropyl)ethylenediamine (DM-BAPEN) with 3 equiv of a salicylaldehyde derivative containing alkyl, alkoxy, or alkylamino substituents in the 4, 5, or 6 position of the aromatic ring. The cationic six-coordinate gallium(III) bis(salicylaldimine) complexes were obtained by reaction of these tris(salicylaldimines) with tris(acetylacetonato)gallium(III). X-ray crystallographic confirmation of the molecular structure of Ga[(4,6-(MeO)2sal)2DM-BAPEN]+I- shows the Ga cation to adopt a pseudo-octahedral N4O2 coordination sphere with a trans configuration. All of the 67Ga complexes are lipophilic with measured octanol/water partition coefficients (P) varying from log P = 0.84 to 3.00. These 67Ga-labeled complexes are all found to exhibit significant myocardial uptake following intravenous administration to rats (ranging from 0.34 to 1.08% of the injected dose in myocardium at 1 min postinjection) combined with the desired myocardial retention of tracer.

A gallium-68 radiopharmaceutical that is retained in myocardium: 68Ga[(4,6-MeO2sal)2BAPEN]+.

The cationic gallium(III) complex formed with the bis(4,6-dimethoxy)salicylaldimine of N,N'-bis(3-aminopropyl)ethylenediamine has been investigated as a potential 68Ga radiopharmaceutical for imaging the heart with PET. The 67Ga complex of this ligand was prepared by ligand exchange from 67Ga-acetylacetonate and its biodistribution determined in ether anesthetized rats following intravenous injection. At 1 min postinjection, 1% of the injected dose was found in the heart with heart-to-blood and heart-to-lung ratios of 2.3:1 and 1.9:1, respectively. No clearance of 67Ga radioactivity from the heart was observed over the 1-min to 2-hr time frame studied. The 68Ga complex of this ligand was also prepared and the tracer further evaluated in a PET imaging study with a normal dog. Beyond 20 min postinjection, the heart was clearly delineated in the 68Ga PET images with good heart-to-blood and heart-to-lung contrast. No clearance of myocardial 68Ga radioactivity was observed over the 90-min imaging period, which is consistent with the results obtained in the rat. Gallium-68 complexes of this type may be useful as radiopharmaceuticals for imaging the heart with PET.