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- Sheppard, L J, et al.
(författare)
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Do nitrogen additions change the sensitivity of detached shoots from Sitka and Norway spruce to freezing temperatures? Evidence from three field manipulation studies
- 2003
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 18:6, s. 487-498
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Tidskriftsartikel (refereegranskat)abstract
- Controversy surrounds the impact of atmospheric nitrogen (N) deposition on frost hardiness. There are no specific field studies and the relevance of data from N fertilizer studies is questionable. Field N manipulation experiments with Norway spruce [Picea abies . (L) Karst.] at Skogaby, Sweden, and Sitka spruce [P. sitchensis . (Bong.) Carr.] at Aber in Wales and Deepsyke in Scotland were sampled in November/December to assess hardiness. The N was supplied with different accompanying ions, from 35 to 100 kg N ha(-1) yr(-1), as solid fertilizer, in irrigation water or to the canopy. Detached shoots were experimentally frozen and damage was assessed from electrolyte leakage. Frost hardiness was not significantly affected by the N treatments irrespective of site, dose, species or length of treatment. Shoots that had received N were generally the most hardy. The results are consistent with the nutritional status of the foliage at the time of sampling.
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| 2. |
- Trainer, P J, et al.
(författare)
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Treatment of acromegaly with the growth hormone-receptor antagonist pegvisomant.
- 2000
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Ingår i: The New England journal of medicine. - 0028-4793. ; 342:16, s. 1171-7
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Tidskriftsartikel (refereegranskat)abstract
- Patients with acromegaly are currently treated with surgery, radiation therapy, and drugs to reduce hypersecretion of growth hormone, but the treatments may be ineffective and have adverse effects. Pegvisomant is a genetically engineered growth hormone-receptor antagonist that blocks the action of growth hormone.We conducted a 12-week, randomized, double-blind study of three daily doses of pegvisomant (10 mg, 15 mg, and 20 mg) and placebo, given subcutaneously, in 112 patients with acromegaly.The mean (+/-SD) serum concentration of insulin-like growth factor I (IGF-I) decreased from base line by 4.0+/-16.8 percent in the placebo group, 26.7+/-27.9 percent in the group that received 10 mg of pegvisomant per day, 50.1+/-26.7 percent in the group that received 15 mg of pegvisomant per day, and 62.5+/-21.3 percent in the group that received 20 mg of pegvisomant per day (P<0.001 for the comparison of each pegvisomant group with placebo), and the concentrations became normal in 10 percent, 54 percent, 81 percent, and 89 percent of patients, respectively (P<0.001 for each comparison with placebo). Among patients treated with 15 mg or 20 mg of pegvisomant per day, there were significant decreases in ring size, soft-tissue swelling, the degree of excessive perspiration, and fatigue. The score fortotal symptoms and signs of acromegaly decreased significantly in all groups receiving pegvisomant (P< or =0.05). The incidence of adverse effects was similar in all groups.On the basis of these preliminary results, treatment of patients who have acromegaly with a growth hormone-receptor antagonist results in a reduction in serum IGF-I concentrations and in clinical improvement.
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