The load of short telomeres, estimated by a new method, Universal STELA, correlates with number of senescent cells.

Short telomeres are thought to trigger senescence, most likely through a single - or a group of few - critically shortened telomeres. Such short telomeres are thought to result from a combination of gradual linear shortening resulting from the end replication problem, reflecting the division history of the cell, superimposed by a more stochastic mechanism, suddenly causing a significant shortening of a single telomere. Previously, studies that have tried to explore the role of critically shortened telomeres have been hampered by methodological problems. With the method presented here, Universal STELA, we have a tool that can directly investigate the relationship between senescence and the load of short telomeres. The method is a variant of the chromosome-specific STELA method but has the advantage that it can demonstrate short telomeres regardless of chromosome. With Universal STELA, we find a strong correlation between the load of short telomeres and cellular senescence. Further we show that the load of short telomeres is higher in senescent cells compared to proliferating cells at the same passage, offering an explanation of premature cell senescence. This new method, Universal STELA, offers some advantages compared to existing methods and can be used to explore many of the unanswered questions in telomere biology including the role that telomeres play in cancer and aging.

[Effect of healthy school meal on selection of blood parameters]. / Effekten af sund skolekost på udvalgte blodparametre.

INTRODUCTION: It was tested if a healthy school meal would result in significant changes in selected blood parameters and if such parameters would lie within generally accepted optimal values. MATERIAL AND METHODS: The study was a block-randomized, controlled trial in which 145 pupils delivered blood before (week 39) and after the intervention (week 49). The intervention group received a healthy meal for two months (25-30% of the daily intake of calories). Blood samples were analyzed for 17 parameters related to carbohydrate, fat and protein metabolism as well as vitamins and minerals. RESULTS: During the intervention period, the intervention group showed a significant change in mean values for thyroid-stimulating hormone (TSH), calcium (CA) haemoglobin (HB), cobalamin (COBA) and creatinine (CREA) compared with the control group (p < 0.025). The optimal value for vitamin D in serum is about 80 nmol/l. In week 49, more than 94% of the pupils were lower than 80 nmol/l, and they generally had low calcium values. CONCLUSION: The intervention group showed significant alterations in TSH, CA, HB, COBA and CREA values from the start to the end of the intervention period compared with the control group. The results should be confirmed in a study with more participants over a longer period of time. The teenagers in the study did not have sufficient vitamin D. Treating adolescents with a daily dose of vitamin D should be considered .