Mikä on metsä ja mitä on suojelu?

Tieteen tor

The effect of vernal solar UV radiation on serum 25-hydroxyvitamin D concentration depends on the baseline level : observations from a high latitude in Finland

Humans obtain vitamin D from conversion of 7-dehydrocholesterol in the skin by ultraviolet B (UVB) radiation or from dietary sources. As the radiation level is insufficient in winter, vitamin D deficiency is common at higher latitudes. We assessed whether vernal solar UVB radiation at latitudes 61 degrees N and 67 degrees N in Finland has an impact on serum 25-hydroxyvitamin D [S-25(OH) D] concentrations. Twenty-seven healthy volunteers participated in outdoor activities in snow-covered terrain for 4-10 days in March or April, with their face and hands sun-exposed. The personal UVB doses and S-25(OH) D levels were monitored. A mean UVB dose of 11.8 standard erythema doses (SED) was received during an average of 12.3 outdoor hours. The mean S-25(OH) D concentration in subjects with a baseline concentration below 90.0 nmol/L (n=13) increased significantly, by 6.0 nmol/L from an initial mean of 62.4 nmol/L (pPeer reviewe

Narrowband Ultraviolet B Exposures Maintain Vitamin D Levels During Winter : A Randomized Controlled Trial

Exposure to solar ultraviolet B radiation during the summer months is the main source of vitamin D (VD) for people living in northern latitudes. The aim of this study was to determine whether artificial narrowband ultraviolet B (NB-UVB) whole-body exposures could maintain VD levels in winter. The intervention group received 2 standard erythema doses (SEDs) of NB-UVB exposures every second week from October 2013 to April 2014. In October 2013 serum 25-hydroxyvitamin D concentrations were 78.3 nmol/l in the intervention group (n=16) and 76.8 nmol/l in the control group (n=18). By April 2014 the concentrations had increased by 11.7 nmol/l (p=0.029) in the intervention group and decreased by 11.1 nmol/l (p=0.022) in the control group. The baseline VD concentration showed a negative correlation (p=0.012) with body mass index (BMI). In conclusion, a suberythemal NB-UVB dose of 2 SED every second week maintains and even increases serum VD concentrations during the winter. A high BMI seems to predispose subjects to low levels of VD.Peer reviewe

Chronic Gastritis in Dermatitis Herpetiformis: A Controlled Study

Background and Objective. Previous small studies suggest that chronic atrophic gastritis is common in dermatitis herpetiformis (DH). We here examined the frequency and topography of chronic gastritis in 93 untreated DH subjects and in 186 controls with dyspepsia. Methods. Specimens were drawn from the gastric corpus and antrum and examined for atrophy, intestinal metaplasia, and Helicobacter pylori. Duodenal biopsies were taken. Results. Atrophic corpus gastritis was more frequent in DH than in controls (16.0% and 2.7%, resp., P < 0.001); atrophy in the antrum was rare in both groups (3.2% and 1.1%, P = 0.34). Intestinal metaplasia was present in 13 (14.0%) DH and 12 (6.5%) control patients (P = 0.038) and H. pylori in 17 (18.3%) and 17 (9.3%) (P = 0.028), respectively. Small-bowel villous atrophy was seen in 76% of the DH patients, equally in patients with and without chronic gastritis. One DH patient with atrophic gastritis developed gastric cancer. Conclusion. In DH, chronic atrophic gastritis was common in the corpus, but not in the antrum. H. pylori will partly explain this, but corpus atrophy is suggestive of an autoimmune etiology. Atrophic gastritis may increase the risk of gastric cancer. We advocate performing upper endoscopy with sufficient histologic samples in DH