Heat penetration in locally applied hyperthermia in the abdomen during intra-operative hyperthermic intraperitoneal chemotherapy.

BACKGROUND: Hyperthermic intraperitoneal chemotherapy (HIPEC) with mitomycin C has been applied following cytoreductive surgery for various peritoneal surface malignancies. The aim of this study was to evaluate heat penetration in the abdomen during 10 HIPEC procedures. MATERIALS AND METHODS: Temperature measurements were taken at 5 levels through the abdominal wall. Core temperature and room temperature were also measured. The relationships between the temperature gradient and room or core temperature were studied. RESULTS: At the start of perfusion, the temperature was estimated on average to be 40.6 degrees C at the first level, then it decreased by 1.7 degrees C (SD 1.0 degree C, p = 0.0001) in the first mm. In outward direction, it decreases by a further 1.5 degrees C per cm (SD 0.3 degree C/cm, p < 0.0001). The core temperature influenced the temperature gradient; the room temperature was not found to be a significant factor. At the end of perfusion, the temperature is estimated on average to be 40.1 degrees C at the first level, then it decreased by 0.8 degree C (SD 0.7 degree C, p = 0.011) in the first mm. In an outward direction, it decreased by a further 1.7 degrees C per cm (SD 0.4 degree C/cm, p = 0.0001). No evidence of an association between the temperature gradient and the room temperature or the core temperature was observed. CONCLUSION: Hyperthermia used during HIPEC procedures has a limited penetration depth. The slope in temperature seems to be related to the core temperature.

Extensive cytoreductive surgery followed by intra-operative hyperthermic intraperitoneal chemotherapy with mitomycin-C in patients with peritoneal carcinomatosis of colorectal origin.

Peritoneal seeding from colorectal cancer has a very poor prognosis and is relatively resistant to systemic chemotherapy. We performed a phase I/II trial to investigate the feasibility and effectiveness of extensive cytoreductive surgery in combination with intra-operative hyperthermic intraperitoneal chemotherapy (HIPEC) in these patients. 29 patients with peritoneal carcinomatosis of colorectal origin without evidence of distant metastases underwent cytoreductive surgery and intra-operative HIPEC with mitomycin-C (MMC), followed by systemic chemotherapy with 5-fluorouracil (5-FU)/leucovorin. Surgical complications occurred in 11 patients (38%). One patient died directly related to the treatment, resulting in a mortality rate of 3%. MMC toxicity existed mainly of leucocytopenia (in 15 patients; 52%). After a median follow-up of 38 months (range 26-52 months) we found a 2- and 3-year survival rate (Kaplan-Meier) of 45 and 23%, respectively. Extensive cytoreductive surgery and HIPEC is feasible in patients with peritoneal seeding of colorectal cancer. First results suggest that a higher median survival could be achieved compared with conventional palliative surgery and systemic chemotherapy, therefore a randomised phase III study is now being conducted.

Extensive surgical cytoreduction and intraoperative hyperthermic intraperitoneal chemotherapy in patients with pseudomyxoma peritonei.

BACKGROUND: Pseudomyxoma peritonei remains a fatal disease. However, extensive surgical cytoreduction combined with intraoperative heated intraperitoneal chemotherapy (HIPEC) has recently emerged as a new treatment modality, which might improve survival. METHODS: Patients underwent treatment if the tumour appeared to be technically resectable on preoperative abdominal computed tomography and there were no distant metastases. After aggressive surgical cytoreduction, HIPEC with the administration of mitomycin C was performed for 90 min. Depending on histological grading, patients received adjuvant 5-fluorouracil and leucovorin therapy. RESULTS: Forty-six patients were treated. Optimal surgical cytoreduction was obtained in 40 patients. Postoperative surgical complications occurred in 18 patients. Four patients died as a direct result of the treatment. Bone marrow suppression due to mitomycin C toxicity occurred in 22 patients. There was no other major toxicity related to the HIPEC procedure. After a median follow-up of 12 months, 40 patients are alive, eight of whom have proven recurrence. The actuarial survival rate (Kaplan-Meier) at 3 years was 81 per cent. CONCLUSION: These results confirm that extensive surgery combined with HIPEC is feasible in patients with pseudomyxoma peritonei and that improved long-term survival might be achieved.

Long-term functional morbidity after mild hyperthermic isolated limb perfusion with melphalan.

AIMS: To assess long-term functional morbidity in patients entered in the prospective randomized EORTC trial investigating the role of adjuvant isolated limb perfusion (ILP) with melphalan for high-risk primary melanoma. METHODS: In 65 patients (ILP 36, wide excision only 29), limb circumference and joint mobility measurements were performed on the treated and the contralateral limb after a mean interval of 48 months after primary treatment. The two treatment groups were comparable regarding age, sex distribution, percentage of skin grafts or regional lymph-node dissections, and interval between primary treatment and physical measurements. RESULTS: None of the patients had severe complaints of the treated limb at the time of analysis. The ankle suffered most from ILP, with a statistical significant restricted extension in approximately 40% of the perfused patients. Abduction of the shoulder was minimally affected in treated upper limbs, probably as a result from the formation of scar tissue after axillary lymph-node dissection. Although no significant differences could be demonstrated in the circumference of upper or lower limbs, atrophy was seen in 24% of perfused lower limbs. Of the five perfused patients who developed oedema, four had also undergone a regional lymph-node dissection. CONCLUSION: This risk of long-term functional morbidity should be weighed against the possible advantages of ILP in patients with limb melanoma or sarcoma.

The effect of pH on the Ca2+ affinity of the Ca2+ regulatory sites of skeletal and cardiac troponin C in skinned muscle fibres.

It is known that intracellular pH drops rapidly after the onset of ischemia in cardiac muscle and may play some role in the rapid drop in force that ensues. It is also known that alpha 1-adrenoceptor agonists alkalinize intracellular pH by stimulating Na+/H+ exchange and may represent a mechanism which facilitates recovery of intracellular pH from acidosis. Lowering or raising pH shifts the Ca2+ dependence of force development in muscle fibres to higher or lower free Ca2+ concentrations, respectively, yet the precise mechanism is unknown. To investigate this phenomenon we have used skinned skeletal or cardiac muscle fibres whose endogenous troponin C (TnC) has been replaced with chicken skeletal TnC labelled with DANZ (STnCDANZ) or recombinant cardiac TnC labelled with IAANS (CTnC3(C84)[AANS), respectively. The fluorescence of the STnCDANZ or CTnC3(C84)IAANS was enhanced by Ca2+ binding to the Ca(2+)-specific (regulatory) site(s) of STnC or CTnC when incorporated into skinned fibres, and was measured simultaneously with force. When the pH was changed from 7.0 to 6.5 or 7.5 the shift in the Ca2+ dependence of force paralleled the shift in fluorescence. Since the force and fluorescence shift in parallel as the pH is lowered or raised, it can be concluded that these changes in Ca2+ sensitivity are caused by a decrease or increase, respectively, in the Ca2+ affinity of the Ca(2+)-specific site(s) of TnC. Since lowering or raising the pH also resulted in lower or higher, respectively, maximal Ca2+ activated force while maximal fluorescence remained unchanged, it is possible that H+ may act indirectly, as well, by reducing or increasing, respectively, the number or type of crossbridges attached to actin and thereby alter the crossbridge induced depression or elevation, respectively of the observed TnC Ca2+ affinity. Experiments with 2,3-butanedione monoxime, however, where force-generating crossbridges were greatly reduced, indicated that the pH effect may be primarily related to a direct change in the Ca2+ affinity to the regulatory sites of TnC.

Value of laboratory tests in monitoring acute regional toxicity after isolated limb perfusion.

BACKGROUND: Severe limb toxicity following isolated limb perfusion (ILP) can lead to compartmental compression syndrome and severe rhabdomyolysis, occasionally necessitating amputation of the affected limb. We determined whether laboratory tests for muscle damage and inflammation could predict impending limb toxicity. METHODS: All 184 consecutive ILPs performed in our institute from 1988 to 1994 were included in this study. Creatine kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransferase (ASAT) and white blood cell (WBC) counts were determined on post-ILP days 1-4, 6, 8, and 15. RESULTS: "Late peak" CK patterns, characterised by a peak on or after the 5th post-perfusion day, were strongly associated with severe limb toxicity (p < 0.001). Severe toxicity did develop in 40% of the limbs when CK values exceeded 1000 IU/L on the 2nd to 5th post-ILP day (p < 0.001). There was a correlation between the peak CK and the individual grades of toxicity (r = 0.6, p < 0.001). Serum LDH and ASAT values peaked 2.9 and 3.4 days after the CK peak respectively. Severe limb toxicity was statistically significantly associated with higher WBC counts from the 2nd post-ILP day onwards. CONCLUSIONS: CK values exceeding 1000 IU/L after the 1st and WBC counts increasing after the 2nd post-ILP day could be predictors of impending limb toxicity. These patients should be observed closely for signs of compartmental compression syndrome and severe rhabdomyolysis.

Physiological implications of hyperbaric oxygen tensions in isolated limb perfusion using melphalan: a pilot study.

Controversy exists concerning the optimal pO2 of the perfusate during isolated limb perfusion (ILP) with melphalan. Therefore we studied the implications of hyperbaric oxygen tensions in the perfusate. In 12 consecutive patients, subcutaneous pO2 (Continucath 1000), tissue and tumor pH, and blood gas values were monitored throughout the ILP procedure. ILP started with an oxygen flow through the bubble oxygenator which was set routinely at one half of the flow of the perfusate; 30 min before the end of ILP, the oxygen flow was tripled. Mean arterial pO2 before and during ILP (before and after increasing the oxygen supply) was 19.4, 25.5 and 49.4 kPa, respectively. Mean subcutaneous pO2 values before, during (before and after increasing the oxygen supply), and post-ILP, were 7.4, 10.1, 16.3, and 9.1 kPa, respectively. Tissue pH values in the subcutis and muscle decreased during routine oxygen supply (p = 0.001); muscle pH moved towards starting values after increase of the oxygen supply (p = 0.011). In 4 patients, tumor pH was recorded showing a rise after increasing the oxygen supply (from 7.10 to 7.22; p = 0.11). In conclusion, high pO2 in the perfusate improves muscle pH during ILP. However, a concomitant rise in tumor pH may unfavorably influence the therapeutic effect of ILP, as it has been shown that low pH increases the cytotoxicity of melphalan.

Severe acute regional toxicity after normothermic or 'mild' hyperthermic isolated limb perfusion with melphalan for melanoma.

Incidence, nature and cause of severe acute regional toxicity were studied in 181 patients who underwent normothermic (37-38 degrees C) or 'mild' hyperthermic (38-40 degrees C) isolated limb perfusion (ILP) with melphalan. The known risk factors for toxicity (sex, tissue temperature, blood gas values, isolation level and melphalan peak concentration) were analysed. Severe acute regional toxicity occurred in 30 patients (16%). The limb was painful, swollen, red and warm in 19, often with a smooth and glistening aspect. Blistering scattered over the extremity was seen in 11 cases. In another 11 patients, late blistering limited to the footsole or handpalm developed. Twenty-six patients with severe toxicity had undergone ILP at the iliac isolation level (p < 0.05). Sex and tissue temperature did not predict toxicity. Venous perfusate blood gas values were severely deteriorated in four patients; high calculated melphalan peak concentrations occurred in nine patients. Irreversible long-term morbidity as a sequence of severe toxicity occurred in 10 of the 30 patients. Only one of the 11 patients with late blisters limited to sole or palm developed long-term morbidity (p < 0.05). Thus, the only risk factor for severe acute regional toxicity that could be identified was iliac isolation level. However, in 27 of the 30 patients two or more risk factors were found.

Caffeine-evoked, calcium-sensitive membrane currents in rabbit aortic endothelial cells.

1. Single cell photometry and whole-cell patch clamp recording were used to study caffeine-induced intracellular Ca2+ signals and membrane currents, respectively, in endothelial cells freshly dissociated from rabbit aorta. 2. Caffeine (5 mM) evoked a transient increase in [Ca2+]i in fura-2-loaded endothelial cells. Pretreatment of cells with 10 microM ryanodine did not alter resting [Ca2+]i but irreversibly inhibited the caffeine-induced rise in [Ca2+]i. The caffeine-induced increase in [Ca2+]i was not attenuated by the removal of extracellular Ca2+ and did not stimulate the rate of Mn2+ quench of fura-2 fluorescence. 3. Bath application of caffeine evoked a dose- and voltage-dependent outward current. The rate of onset and amplitude of the caffeine-evoked outward current increased with higher caffeine concentrations and membrane depolarization. The relationship between caffeine-evoked current amplitude and membrane potential was non linear, suggesting that the channels underlying the current are voltage-sensitive. 4. In the absence of extracellular Ca2+, the amplitude of the caffeine-evoked outward current was reduced by approximately 50% but the duration of the current was prolonged compared to that observed in the presence of external Ca2+. Ca(2+)-free external solutions produced an unexpected increase in both the frequency and amplitude of spontaneous transient outward currents (STOCs). 5. Inclusion of heparin (10 micrograms ml-1) in the patch pipette abolished the acetylcholine (ACh)-induced outward current but failed to inhibit either STOCs or the caffeine-evoked outward current in native endothelial cells. In the absence of extracellular Ca2+, heparin did not affect either STOCs or the caffeine-induced outward current. 6. Externally applied tetraethylammonium ions (TEA, 3-10mM) reversibly inhibited unitary Ca2+-activated K+ currents and STOCs in endothelial cells but failed to inhibit completely the outward current evoked by 20 mM caffeine.7. Bath application of 0.1 mM zinc ion (Zn2+), a chloride channel blocker, did not affect unitary currents or STOCs but reduced the amplitude of the caffeine-evoked current by >75% compared to control. Replacement of extracellular NaCl with Na gluconate also reduced the amplitude of the caffeine-induced outward current. Bath application of 0.1 mM Zn2+ and 10 mM TEA completely blocked the caffeine-evoked outward current in endothelial cells.8. Caffeine-induced Ca2+ release from intracellular stores evokes a transient rise in [Ca2+1, which is correlated with a large, transient outward current. The ionic dependence and inhibition of the caffeine sensitive current by TEA and Zn2+ suggests that Ca2+-activated K+ and Cl- conductances contribute to the caffeine response in rabbit aortic endothelial cells.

Melphalan tissue concentrations in patients treated with regional isolated perfusion for melanoma of the lower limb.

In 14 consecutive patients with recurrent melanoma of the lower limb a total of 35 biopsies were taken at the end of perfusion treatment to assess melphalan tissue concentrations in tumour, skin/subcutis and muscle tissue. In tumour tissue (n = 12) the mean melphalan concentration was 6.8 micrograms g-1, which was significantly higher than that of healthy skin/subcutis (3.2 micrograms g-1; n = 10), but equal to that of muscle tissue (6.5 micrograms g-1; n = 13). The correlation between melphalan concentration in the tissues and the concentration in the perfusate was studied. The latter was assessed in the form of melphalan peak concentration and the area under the curve (AUC0-->60) of the melphalan concentration-time curve. Tumour concentration proved to be correlated linearly with AUC0-->60 (R = 0.6, P = 0.002) and muscle concentration with melphalan peak concentration (R = 0.8, P = 0.04). There was no relation between skin/subcutis concentrations and the perfusate parameters. Further research is warranted to study the relationship between melphalan tissue concentration, tumour response and regional toxicity.

Comparison between the use of whole blood versus a diluted perfusate in regional isolated perfusion by continuous monitoring of transcutaneous oxygen tension: a pilot study.

In 12 successive women (median age, 58 [39-89] years) who were treated with regional isolated perfusion for melanoma of the lower extremities, peroperative continuous monitoring of the transcutaneous oxygen tension (PtcO2) was performed as an indicator for tissue oxygenation and (sub)cutaneous perfusion. Regional perfusion started using whole blood as perfusate with a hematocrit of 40.7 +/- 4.9. After 40 min of drug circulation the perfusate was diluted to a hematocrit of 25.3 +/- 4.9, a value usually applied in perfusion. Flow rates (mean 51.2 +/- 14.4 mL/min/L perfused tissue) were kept at a level that caused no systemic leakage and no more than 10-cm increase above starting venous pressure. Oxygen supply was set at one half of the flow of the perfusate (in mL/min). The mean PtcO2 during the first part of perfusion, in which seven patients could achieve preperfusion levels for at least some of the time, was significantly higher than during the last part, in which no patient reached the preperfusion level (30.8 mm Hg vs 23.5 mm Hg; p = .0019). The mean maximal decrease in PtcO2 after dilution was 21.3 +/- 11.6 mm Hg. Venous blood gases of the perfusate also deteriorated after dilution. Two patients encountered a grade III and two a grade IV toxicity reaction after perfusion. We conclude that increasing the hematocrit of the perfusate to physiologic levels by using whole blood can guarantee a physiologic tissue oxygenation at relatively low flow rates. However, physiologic tissue oxygenation on its own is not enough to prevent toxicity after perfusion.