The overall metabolism in tumour cells from 36 untreated patients with non‐Hodgkin lymphoma was evaluated by direct calorimetry. For 20 patients with lymphoma of high grade malignancy the median value of heat production rate per tumour cell was 3.9 pW and for 16 patients with low grade lymphomas the corresponding value was 2.8 pW. The difference between the two morphclogical groups is significant (p = 0.05). The median value of heat production rate per tumour cell from 13 patients who died within 2 yr after diagnosis was 4.0 pW. The corresponding value for 17 patients who have survived for more than 2 yr was 2.5 pW. The difference between the two groups is significant (p = 0.02). A high correlation was found between heat production rates in tumour cells and survival of the patients (p = 0.006).
Heat production rates (thermal power) in peripheral blood lymphocytes from healthy subjects were determined under some defined experimental conditions in an attempt to establish by microcalorimetry a basal metabolic reference range for lymphocytes in the non-activated state. The effects of cell isolation method, the presence of other types of blood cells, cell concentration, temperature, pH and type of suspension medium on the rate of heat production by lymphocytes were evaluated. The results indicate that microcalorimetry is suitable for monitoring the metabolism of these cells with good precision in the physiological range of cell concentration.
Abstract.
A discrepancy between the clinical impression of disease activity and basal serum levels of growth hormone is often seen in patients with acromegaly. A slightly better relation has been found to serum levels of IGF-I, but a technique for evaluation of cell metabolic activity in this disease is still missing. For this purpose we used microcalorimetry to determine heat production rate in lymphocytes from 15 patients with acromegaly. The mean heat production rate was 2.90±0.15 pW/cell, significantly higher than in 13 healthy subjects, 2.31±0.12 pW/cell (p<0.01). Heat production rates did not correlate significantly with basal growth hormone levels, but increased, in a statistically significant manner (p<0.001), in parallel with the score index used to evaluate the clinical activity of the disease. Using the technique of microcalorimetry we could thus demonstrate an increased metabolic activity at a cellular level in patients with acromegaly, a finding that is in accordance with the view that an increased cell metabolic activity is a component of the disease process in acromegaly.
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