Microregional distributions of glucose, lactate, ATP and tissue pH in experimental tumours upon local hyperthermia and/or hyperglycaemia.

Microregional distributions of glucose, lactate and ATP concentrations as well as tissue pH values were determined in subcutaneous rat tumours during normothermia and normoglycaemia, and upon local hyperthermia (HT) and/or hyperglycaemia (HG). Experiments were performed in order to investigate whether, and to what extent, these adjuvant therapeutic measures applied alone or in combination can modify the bioenergetic and metabolic status, parameters that are known to markedly influence the therapeutic response of tumours to heat. Local HT was performed in a saline bath (44 degrees C/2 h) and HG was induced by i.v. infusion of glucose for 2.5 h (blood glucose levels during heating: 35-40 mM). Immediately after treatment, the microregional distributions of glucose, lactate and ATP concentrations were assessed using quantitative bioluminescence and single-photon counting. In corresponding histological sections the fraction of tumour tissue with changes indicating cellular damage was determined. For comparison, global levels of glucose, lactate, ATP, ADP and AMP were measured using enzymatic assays or HPLC. Tumour tissue pH values were recorded immediately after treatment with miniaturised needle glass pH electrodes. Upon HT alone, the microregional glucose distribution remained unchanged. Lactate concentrations significantly increased, resulting in a pH drop of about 0.20 pH units. Mean ATP concentrations decreased without an obvious change in the shape of the distribution curve. The fraction of tumour tissue showing cellular damage increased from 18% (in control tumours) to 27%. Upon HG alone, mean glucose and lactate levels in the tumours increased. Glucose, lactate and pH distributions became broader. Lactate accumulation results in a severe tumour acidosis (mean pH = 6.22). Mean ATP concentrations marginally decreased despite a higher glucose availability, probably because of poorer ATP yield resulting from changes in metabolic channelling (Crabtree effect). The fraction of tumour tissue exhibiting cellular damage was 23%. Following the combined treatment (HT/HG), glucose and lactate levels, and tissue pH were similar to those seen upon HG alone. However, ATP concentrations were lowest under this condition. The variation of tumour ATP concentrations is substantially reduced with only a few tumour areas remaining with ATP levels of at least 0.6 mumol/g. The ATP depletion upon HT/HG is accompanied by a drastic increase in the fraction of tissue areas exhibiting cellular damage to 61%. It may therefore be concluded that only the combined treatment can deplete ATP to such an extent that a pronounced cytotoxic effect is achieved.

Acute changes of systemic parameters in tumour-bearing rats, and of tumour glucose, lactate, and ATP levels upon local hyperthermia and/or hyperglycaemia.

Arterial blood pressure and relevant parameters of the arterial blood (O2 and CO2 tensions, pH, haematocrit, serum electrolytes and osmolality) were determined in tumour-bearing rats upon local hyperthermia (HT) and/or hyperglycaemia (HG). Tumour heating was performed in a saline bath (44 degrees C) for 120 min; hyperglycaemia was induced by i.v. infusion of 40% glucose solution for 150 min [blood glucose levels: 35-40 mM during heating; total amount of glucose: 1.19 g/100 g body wt.; infusion rates: 0.31 ml (100 g body wt.)-1 min-1 for 2 min, 0.02 ml (100 g body wt.)-1 min-1 for 88 min, and 0.01 ml (100 g body wt.)-1 min-1 for 60 min]. Immediately after treatment, glucose, lactate and ATP levels were determined in tumour and muscle specimens and compared to these values under normothermic (NT) and/or normoglycaemic (NG) conditions. In all groups (NT/NG, NT/HG, HT/NG, HT/HG) there were only minor but characteristic changes in blood parameters, which were mainly due to the volume and type of the infused fluids (glucose solution, saline). During hyperglycaemia, tumour glucose levels rose 13- to 17-fold, whereas muscle glucose concentrations exhibited only a 3- to 5-fold increase; lactate levels were 1.9-2.5 times higher in tumours than in muscle, indicating an increase in the metabolic differences between normal and malignant tissues. Despite an increased glucose availability, tumours did not show an improved energy status and, thus, would not be expected to develop a decrease in thermal sensitivity or stimulation in growth rate. The good systemic tolerability of the combined treatment (HT/HG) and the differential changes in malignant and normal tissue occurring under these conditions, support further attempts to manipulate tumour metabolic environment by glucose in order to achieve better therapeutic results.

Laser Doppler flux and tissue oxygenation of experimental tumours upon local hyperthermia and/or hyperglycaemia.

Laser Doppler fluxmetry and oxygen partial pressure (pO2) histography have been applied to investigate the acute effects of hyperthermia (HT) and/or hyperglycaemia (HG) on microcirculatory function and tissue oxygenation of subcutaneous rat tumours growing on the dorsum of the hind foot. The experiments were performed to test whether, and to what extent, the two adjunct treatment modalities applied alone or in combination can modify these therapeutically relevant parameters. Local HT was performed in a saline bath (44 degrees C) for 2 h; HG was induced by i.v. infusion of 40% glucose solution for 2.5 h (blood glucose levels: 35-40 mM during heating). Laser Doppler flux (LDF) in superficial tumour tissue regions was recorded over the entire treatment period; tumour pO2 distribution was evaluated immediately after termination of the treatment. HG alone reduced the average LDF signal to 18% of the baseline reading before treatment, but did not influence the tumour oxygenation status and the proportion of pO2 readings occurring in the radiobiologically hypoxic class (pO2 = O-2.5 mm Hg). This phenomenon is most probably due to the occurrence of the Crabtree effect (reduction of the O2 consumption rate when excess glucose is available within a malignant tumour). Hyperthermia alone reduced LDF to approximately the same extent, and led to a rise in the number of pO2 readings in the hypoxic range with only minor changes in the average pO2. The combined treatment (HT/HG) neither increased the fraction of "hypoxic" pO2 readings nor intensified the flow drop already present at the end of the tumour heating. It is thus concluded that under hyperglycaemia the oxygenation status of normothermic and heated tumours is maintained. It may therefore be hypothesized that hyperthermia in conjunction with hyperglycaemia might be a better "radiosensitizer" than hyperthermia alone.

Evaluation of systemic tolerance of 42.0 degrees C infrared-A whole-body hyperthermia in combination with hyperglycemia and hyperoxemia. A Phase-I study.

PURPOSE: In September 1965, Manfred von Ardenne presented in the Heidelberg Cancer Research Centre the concept of his so-called systemic Cancer Multistep Therapy--a combined modality treatment including whole-body hyperthermia. At the time, whole-body hyperthermia was attained by a warm water bath plus induced hyperglycemia and a high dosage application of oxygen. After 25 years of basic research, methodical processing and further development of a practical infrared-A hyperthermia technology, the therapy achieved clinical maturity. Within the framework of a clinical phase-I study that was carried out in 1991, we set out to prove the systemic tolerability of systemic Cancer Multistep Therapy. PATIENTS AND METHODS: 103 patients, who had been previously treated with virtually all forms of conventional treatment in its most extensive form and who were in a stage of uncontrollable progression with metastasis growth and/or recurrent primary tumors, were treated within the framework of a clinical phase-I study with the objective of reaching a palliative progression stop. Body core temperatures of 41.8 +/- 0.2 degrees C were attained by means of a special infrared-A machine named IRATHERM 2000 with the aim of reaching a plateau phase of 60 to 70 min. A high dosage of glucose (10% glucose solution, 500 to 700 ml/h, blood glucose level 410 +/- 90 mg/dl) was administered intravenously to intensify lactacidosis and thereby the thermal sensitivity of the malignant tumors to be treated. Using a laminar flow applicator (up to approximately 30 l/min O2 flow), the arterial oxygen partial pressure paO2 was increased to 163 +/- 50 mm Hg. For premedication and neuroleptic analgesia, a combination of dehydrobenzperidol and fentanyl was used. Blood pressure, ECG, oxygen saturation, blood-gas status and hematocrit were monitored continuously and changes in blood electrolyte concentrations were corrected by appropriate intravenous infusions. In terms of systemic tolerability, systemic Cancer Multistep Therapy (whole-body hyperthermia+hyperglycemia+hyperoxemia) induced pathophysiologically no obviously toxic or otherwise detrimental effects. In isolated cases, sporadic erythemas on low perfused skin areas or occasional emesis were observed after the end of the treatment. RESULTS: The good systemic tolerability of the systemic Cancer Multistep Therapy with only minimal side effects has thus been proven. The hyperthermic IRATHERM machine used to attain the extreme whole-body hyperthermia showed that it was a reliable and practical unit. When UICC criteria and other criteria defined for integrated tumor therapies of systemic character were applied, over 50% of the patients treated had a positive therapeutic response. CONCLUSION: The good systemic tolerability of the systemic Cancer Multistep Therapy on the one hand, and the positive therapeutic influence on the course of the illness on the other hand, justify the intensified continuation of studies on the effectiveness of systemic Cancer Multistep Therapy.

Coronary smooth muscle reactivity to repeated agonist administration in a long-time experiment in vitro.

The reactivity of isolated extramural coronary arteries of the pig to repeated agonist administration (acetylcholine, prostaglandin F2 alpha and K+-contraction) was investigated in a long-time experiment (20 h, more than 60 reactions). The acetylcholine-evoked contractions show an amplitude increase (phasic component) during the first 10 responses followed by approximately 20 constant reactions and a final amplitude decrease with alternative changes in amplitude. The tonic component of the acetylcholine responses decreases uniformly. The amplitude of K+-contraction increases during the first 10 reactions, and remains nearly constant in the further experiment. Prostaglandin F2 alpha produces a maximum contraction already in its first response, but the amplitudes decrease considerably after 6-8 reactions. The time course of the corresponding contraction upstroke velocity is quite similar compared to the amplitude behaviour. Differences in the smooth muscle reactivity between the used agonists are explained by different activatory mechanisms. Some hints concerning an optimum experimental procedure are given.

[Studies of dialysis patients using the 14C aminophenazone breath test]. / Untersuchungen von Dialysepatienten mit dem 14C-Aminophenazon-Atemtest.

In 12 endstage kidney disease patients (8 liver healthy and 4 with liver diseases) the activities of cytochrome P450-dependentmixed functional oxidases system (MFO) of the liver were studied by using the 14C-aminophenazon breath test before and after dialysis. We were interested in the influence of uremia and dialysis treatment on MFO-activity. Our results show that uremia seems to have a pressing influence on MFO-activity. The activity was only significantly increased after dialysis in the group of patients without liver disease. We observed that the MFO-activity was reduced in patients with liver diseases. This is a restriction of the liver metabolic demethylation capacity. It is unclear if the 14C-aminophenazone breath test in dialysis patients is qualified to estimate metabolic capacity of the liver. Differentiation between the influence of uremia and of the liver disease on the alteration of MFO-activity cannot be made.