Hypothesis: the regulation of the partial pressure of oxygen by the serotonergic nervous system in hypoxia.

The regulation of the partial pressure of oxygen by the serotonergic nervous system in hypoxia is a hypothesis, which proposes an inherent operative system in homo sapiens that allows central nervous system and endocrine-mediated vascular system adaption to variables in partial pressure of oxygen, pH and body composition, while maintaining sufficient oxygen saturation for the immune system and ensuring protection of major organs in hypoxic and suboptimal conditions. While acknowledging the importance of the Henderson-Hasselbalch equation in the regulation of acid base balance, the hypothesis seeks to define the specific neuroendocrine/vascular mechanisms at work in regulating acid base balance in hypoxia and infection. The SIA (serotonin-immune-adrenergic) system is proposed as a working model, which allows central nervous system and endocrine-mediated macro- and micro vascular 'fine tuning'.

Microcalorimetric study on myocardial metabolism in a hibernator and two nonhibernators at 20 degrees C and 37 degrees C.

Metabolic activity in cardiac tissue slices from the guinea pig (GP), the rat (RT), the nonhibernating summer and winter hedgehog (SH and WH), respectively, was determined at 20 degrees and at 37 degrees C from their rates of heat production, P, (units, W/g tissue) by direct and indirect calorimetry. Energy-linked transport of Na+ and K+ in the tissues was determined from changes in metabolic rate induced by specific inhibition of the Na/K pump, the functional expression of Na/K-ATPase, the pacemaker enzyme in energy production assigned the role of transporting Na+ and K+ out of and into the cell. The results indicate a higher rate of energy production and utilization in the cardiac tissue of the hedgehog than in that of the nonhibernators, the rat and the guinea pig, at both temperatures.

Increased lymphocyte thermogenesis in hyperthyroid patients. Role of Na/K pump function. Evaluation of aerobic/anaerobic metabolism.

The role of the Na/K pump for the increased cell energy expenditure in hyperthyroidism was studied by measuring total lymphocyte heat production rate in samples with and without ouabain inhibition of Na/K ATP-ase. In addition, the relative contribution of aerobic processes to lymphocyte thermogenesis was calculated from oxygen consumption measurements. In 12 patients with clinical and laboratory hyperthyroidism total lymphocyte heat production rate was 3.

Microcalorimetric evaluation of blood compatibility of hemodialysis membranes.

The study was made in vitro of reactions elicited by contact of granulocytes suspended in autologous plasma with three polymers: polyacrylonitrile (AN); polyetherpoly-carbonate (PC), and regenerated cellulose (Cu). Alterations in basal metabolism and biological function of the human blood granulocytes induced by interfacial reactions were determined by direct microcalorimetry. The polymers, which are commonly used as membranes in artificial kidneys, were found to activate granulocytes to degrees which were inversely correlated with their response to zymosan.

Heat production rate in blood lymphocytes as a prognostic factor in non-Hodgkin's lymphoma.

The heat production rate in peripheral blood lymphocytes was evaluated by direct calorimetry in 76 untreated adults with non-Hodgkin's lymphoma (NHL). Elevated values were recorded for 20 out of 54 patients with lymphomas of high or intermediate malignancy grade (37%) and for 1 out of 22 patients (5%) with low grade lymphomas (p = 0.01).

Thyroid hormones and thermogenesis: a microcalorimetric study of overall cell metabolism in lymphocytes from patients with different degrees of thyroid dysfunction.

We used microcalorimetry to measure lymphocyte heat production rate in patients with clinical and laboratory hyperthyroidism (serum TSH decreases, serum FT4 increases, serum FT3 increases), subclinical hyperthyroidism (serum TSH decreases, serum FT1 increases, serum FT3 =), and subclinical hypothyroidism (serum TSH increases, serum FT4 decreases, serum FT3 =) compared with healthy controls (N = 13). The lymphocyte heat production rate was significantly correlated to the free thyroxine level (r = 0.53, p less than 0.

Cell metabolic activity in acromegaly: a microcalorimetric study of lymphocyte metabolism.

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.

Effects of calcium entry blockers on human platelet metabolism measured by microcalorimetry.

1. The direct overall metabolic effects of calcium entry blockers on human platelets were evaluated using a sensitive microcalorimetric method. 2.

Erythrocyte metabolism in hyperthyroidism: a microcalorimetric study on changes in the Embden-Meyerhof and the hexose monophosphate pathways.

Erythrocyte metabolism was studied in vitro by microcalorimetry in 10 hyperthyroid subjects before and after treatment. By inhibiting the enzyme enolase in the Embden-Meyerhof pathway with sodium fluoride (NaF) we have recorded the anaerobic and aerobic contributions in erythrocyte thermogenesis. The decrease in heat production rate in samples with NaF corresponds to the anaerobic contribution, whereas the values from samples with NaF reflect aerobic processes.

Erythrocyte thermogenesis in hyperthyroid patients: microcalorimetric investigation of sodium/potassium pump and cell metabolism.

Erythrocyte thermogenesis was studied by microcalorimetry in 11 patients before and after treatment for hyperthyroidism. Cell heat production rate and intracellular Na+ and K+ levels were measured in plasma suspensions of erythrocytes with and without specific inhibition of Na/K ATPase by ouabain. The ouabain induced change in the heat production rate (the Na/K pump thermal power); the erythrocyte intracellular Na+ content and the ouabain sensitive Na+ transport were used to estimate the Na/K pump function.

Microcalorimetric studies on the effect of adenosine receptor agonists and xanthine derivatives on overall metabolism in human platelets.

The direct overall metabolic effects of drugs acting on adenosine receptors in human platelets were evaluated using a sensitive microcalorimetric method. Adenosine induced a concentration-dependent increase in the heat production rate at concentrations above 100 microM. The adenosine uptake inhibitor, dipyridamole (3 microM) did not modify the effect of adenosine.

Microcalorimetric investigation of cell metabolism in tumour cells from patients with non-Hodgkin lymphoma (NHL).

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.

Erythrocyte heat production in human obesity: microcalorimetric investigation of sodium-potassium pump and cell metabolism.

Changes in overall cellular metabolism, induced by specific inhibition of the Na-K-pump, were determined in erythrocytes from 33 normal and 25 obese subjects. Cellular metabolism was determined by measurement of heat production rates in erythrocytes suspended in plasma with and without the cardioactive glycoside, ouabain. Specific inhibition with ouabain induced the same decrease of the heat production rate in the two groups (14 +/- 5 mW/L for normal subjects and 13 +/- 5 mW/L for obese subjects).

Heat production in human blood lymphocytes. A methodological study.

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.

Metabolic activity of lymphoma cells and clinical course in non-Hodgkin lymphoma (NHL).

By microcalorimetry the metabolic activity of malignant cells from 2l patients with non-Hodgkin lymphoma was monitored. Heat production, a measure of the metabolic activity of cells, showed positive correlation with the clinical course of the disease. The heat produced by tumor cells from patients with progressive disease was 5.

Heat production by lymphocytes in chronic lymphocytic leukaemia.

Using microcalorimeters of the thermopile conduction type heat production was measured in lymphocytes from peripheral blood in 8 normals and 10 patients with chronic lymphocytic leukaemia (CLL). The heat production per CLL lymphocyte was lower (1.8 pW/cell) than that found in normal lymphocytes (2.