Vitamin D, sunlight and longevity.

Humans acquire vitamin D through skin photosynthesis and digestive intake. Two hydroxylations are needed to obtain the bioactive compound, the first produces 25-hydroxyvitamin D [25(OH)D], and the second 1,25-dihydroxyvitamin D [1,25(OH)2D]. There is no consensus regarding the appropriate cut-off level to define the normal serum 25(OH)D range. Experimental, epidemiological and clinical studies have related low vitamin D status with longevity. Although some results are controversial, low serum 25(OH)D levels have been linked to all-cause, cardiovascular, cancer and infectious related mortality. Throughout life span a significant proportion of human beings display insufficient (20-30 ng/mL) or deficient (<20 ng/mL) serum 25(OH)D levels. Appropriate lifestyle changes, such as regular short exposures to sunlight (15 min a day), and an adequate diet that includes vitamin D rich components, are not always easily accomplished. Studies relating to vitamin D supplementation have methodological limitations or are based on relatively low doses. Therefore, dosages used for vitamin D supplementation should be higher than those traditionally suggested. In this sense, there is an urgent need for prospective controlled studies using high daily vitamin D doses (2,000 IU or higher) including cardiovascular, cancer, infectious and other endpoints. Relationship between vitamin D and health outcomes is not linear, and there are probably various optimal vitamin D levels influencing different endpoints.

[Comparative evaluation of ultrasonography, computerized tomography, angiography and lipiodol CT in defining extent of hepatocarcinoma. A multicenter study]. / Valutazione comparativa dell'ecografia, della Tomografia Computerizzata, dell'angiografia, della Lipiodol TC nel bilancio di estensione dell'epatocarcinoma. Studio multicentrico.

The authors report the results of a multicentric trial on hepatocellular carcinoma (HCC) patients, whose lesions were confirmed with biopsy or by high (> 400 ng/ml) alpha-fetoprotein levels. The series consisted of 149 patients examined in 8 different centers and submitted to ultrasonography (US), Computed Tomography (CT) before and after contrast agent administration, angiography and Lipiodol CT. According to lesion size and number, the patients were divided with each imaging modality into three groups: a) group 1: unifocal HCC < 5 cm diameter; b) group 2: multifocal HCC with 2-3 nodules and/or tumor mass < 80 ml; c) multifocal HCC with more than 3 nodules (with total tumor mass not exceeding 40% of liver volume) or with total tumor mass > 80 ml. In 77 patients all the examinations were available for comparison. US and CT diagnosed more patients as belonging to group 1 than angiography and Lipiodol CT, while more patients were classified as groups 2 and 3 with angiography and Lipiodol CT, meaning that US and CT may understage some HCC cases (about 15%) because they show a lower number of nodules. This observation was confirmed by the direct comparison between US and Lipiodol CT (in 114 patients), CT and Lipiodol CT (in 103 patients) and angiography and Lipiodol CT (in 116 patients). US and Lipiodol CT were in disagreement in 18 cases, CT and Lipiodol CT in 16 cases and angiography and Lipiodol CT in 13 cases. In most of these cases, Lipiodol CT showed more lesions than the other techniques. The size of the undetected lesions was small, ranging few mm to 2 cm in nearly all cases. To conclude, the results of this multicentric trial show that Lipiodol CT is a fundamental tool to evaluate HCC extent. In contrast, conventional CT appeared not to add any significant piece of information and can therefore be excluded from the diagnostic protocol of HCC.