The effects of GH replacement therapy on cardiac morphology and function, exercise capacity and serum lipids in elderly patients with GH deficiency.

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

Laser Doppler perfusion monitoring of skin blood flow at different depths in finger and arm upon local heating.

The purpose of the study was to elucidate the vasodilatory response to local heating of the skin at two depths in two locations. To accomplish this, we measured skin blood flow in 12 healthy subjects using laser Doppler perfusion monitoring. A probe with two fibers separated 0.14 mm (superficial) and 0.25 mm (deeper) from the illuminating fiber was first attached to the distal phalanx of the index finger and thereafter to the dorsal forearm skin. Local heating was caused with a thermostatic probe holder set at 40 degrees C. We studied the perfusion value and its two components, velocity and concentration. All registrations were also subjected to frequency analysis. Laser Doppler values were generally higher in the fingertip than in forearm skin. Heating caused increased values at both locations. Concentration increased relatively more than velocity and this was most obvious in the forearm. There were only slight differences in response between superficial and deeper vascular components. Frequency analysis revealed a peak in perfusion and velocity obviously related to the heartbeat. Movement of the column of blood thus reached the peripheral vascular network without changing concentration. We conclude that local heating increases skin blood flow in fingertip and forearm skin by different adjustments of blood cell concentration and velocity, presumably depending on differing vascular anatomy and physiological control, but differences are of a rather minor character. Furthermore, responses differ just slightly in superficial compartments as probed with fibers separated up to 0.25 mm.