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- Elgzyri, Targ, et al.
(author)
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The effects of GH replacement therapy on cardiac morphology and function, exercise capacity and serum lipids in elderly patients with GH deficiency
- 2004
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In: Clinical Endocrinology. - Oxford : Blackwell Scientific Public.. - 0300-0664 .- 1365-2265. ; 61:1, s. 113-122
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Journal article (peer-reviewed)abstract
- Objectives: To assess effects of GH replacement therapy on cardiac structure and function, exercise capacity as well as serum lipids in elderly patients with GH deficiency (GHD). Patients and methods: Thirty-one patients (six females, 25 males), aged 60–79 years (mean 68 years) with GHD on stable cortisone and thyroxine substitution were studied. All men with gonadotropin deficiency had testosterone and one woman had oestrogen replacement. They were randomized in a double-blind manner to GH or placebo treatment for 6 months, followed by another 12 months GH (Humatrope, Eli Lilly & Co, Uppsala, Sweden). GH dose was 0·017 mg/kg/week for 1 month and then 0·033 mg/kg/week divided into daily subcutaneous injections at bedtime. Echocardiography, exercise capacity tests and serum lipid measurements were performed at 0, 6, 12 and 18 months. Results: During the 6-month placebo-controlled period there were no significant changes in the placebo group, but in the GH-treated group there was a significant increase in IGF-I to normal levels for age, with median IGF-I from 6·9 to 18·5 nmol/l, increase in resting heart rate and maximal working capacity. During the open GH study, IGF-I increased from 8·7 to 19·2 nmol/l at 6 months and 18·8 nmol/l at 12 months (P ≤ 0·001). At 6 months, in the open GH study group, a minor decrease in aortic outflow tract integral (VTI) from 21·8 to 20·7 cm (P = 0·031) and an increase in heart rate at rest from 63 to 67 bpm (P = 0·017), heart rate at maximum exercise from 138 to 144 bpm (P = 0·005) and maximum load at exercise from 142 to 151 Watts (P = 0·014) were seen. These changes were temporary and returned at 12 months with no significant difference from baseline values. Left ventricular dimensions and blood pressure showed no significant changes. At 6 months, in the open GH study group, there was a significant decrease in serum low-density lipoprotein (LDL) cholesterol from 3·7 to 3·4 mmol/l (P = 0·006), a decrease in LDL/HDL ratio from 3·4 to 3·1 (P = 0·036) and a decrease in serum total cholesterol from 5·6 to 5·3 mmol/l (P = 0·036). At 12 months, serum lipids showed same changes with a significant decrease in serum LDL cholesterol (P = 0·0008), in LDL/HDL ratio (P = 0·0005) and in serum total cholesterol (P = 0·049). Serum HDL cholesterol showed no significant change at 6 months, at 12 months a significant increase was seen from 1·2 to 1·4 mmol/l (P = 0·007). There were no significant changes in serum triglycerides. Conclusions: GH substitution to elderly patients with GHD caused only a transient increase in heart rate. At the end of the 12 months there were no significant changes on cardiac noninvasive structural and functional parameters. Maximal working capacity transiently improved. Thus, the therapy was safe without negative effects on cardiac structural and functional noninvasive parameters. Lipid profiles improved with reduction of serum LDL cholesterol accompanied by significant improvement of LDL/HDL ratio and serum HDL cholesterol after 12 months treatment.
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| 2. |
- Zevenhoven-Onderwater, Maria, et al.
(author)
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The ash chemistry in fluidised bed gasification of biomass fuels. Part I : Predicting the chemistry of melting ashes and ash-bed material interaction
- 2001
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In: Fuel. - : Elsevier. - 0016-2361 .- 1873-7153. ; 80:10, s. 1489-1502
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Journal article (peer-reviewed)abstract
- This paper is part I in a series of two describing the modelling of the ash-chemistry of seven biomass fuels under reducing, pressurised conditions in fluidised bed gasification by means of thermodynamic multi-phase multi-component equilibrium (TPCE) calculations. The fuels considered were Salix, a Scandinavian forest residue, Miscanthus, Reed Canary Grass, Eucalyptus, Arundo Donax and Lucerne. The composition and amount of phases have been calculated for the gasification of the fuel as such and in presence of an excess amount of calcite, dolomite, magnesium olivine sand and sand by using TPCE calculations in a temperature interval of 600-900°C and a pressure of 10 bar. It was found that interaction of inorganic compounds released from the fuels with bed material is a prerequisite for the formation of bed agglomerates. The presence of an excess of dolomite decreased the amount of alkali components in the bed, thereby increasing the amount of alkali components volatilised. A silica bed, however, binds most alkali released from the fuel, retaining it in the bed as low melting alkali silicates. The chances of experiencing operating problems due to bed agglomeration may increase hereby significantly. Calculations at atmospheric pressure show that the amounts of melt present will be smaller when compared to pressurised conditions, thereby decreasing the chances of bed agglomeration. In a pressurised gasifier using calcite or dolomite as bed material a small amount of an alkali carbonate rich melt can be expected at temperatures above 620°C with each of the seven biomass fuels fired. In silica-rich cases such as when firing Miscanthus, Reed Canary Grass, Arundo Donax or using a Si-rich bed material a melt can be expected at temperatures above 770°C. The amount of melt is rather high, i.e. 12-100% of the original ash formed. In the case of a magnesium olivine sand bed an alkali melt can be expected at 620°C. At temperatures above 800°C, a silicate melt can form as well. The amount of melt was hi gh, i.e. 60-300% of the original ash formed, showing a significant contribution of the bed material.
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