Percutaneous venovenous perfusion-induced systemic hyperthermia for advanced non-small cell lung cancer: initial clinical experience.

BACKGROUND: Venovenous perfusion-induced systemic hyperthermia raises core body temperature by extracorporeal heating of the blood. Five patients with advanced non-small cell lung carcinoma stage IV (4.4+/-1 months after initial diagnosis) received venovenous perfusion-induced systemic hyperthermia to 42.5 degrees C (core temperature) to assess technical and patient risks. METHODS: After general anesthesia and systemic heparinization (activated clotting time > 300 seconds), percutaneous cannulation of the right internal jugular vein (15F) for drainage and common femoral vein (15F) for reinfusion allowed extracorporeal flow rates up to 1,500 mL/min (20 mL x kg(-1) x min(-1)) with the ThermoChem System. This device uses charcoal-based sorbent for electrolyte homeostasis. Six monitored sites (rectal, bladder, tympanic x2, nasopharyngeal, and esophageal) determined average core temperature. RESULTS: All patients achieved a core target temperature of 42.5 degrees C for 2 hours. Electrolyte balance was maintained throughout hyperthermia (mean) in mmol/L: Na+, 136.2+/-2.2 mmol/L; K+, 4.0+/-0.3 mmol/L; Ca2+, 4.1+/-0.2 mg/dL; Mg2+, 1.9+/-0.1 mg/dL; PO4-, 4.5+/-0.9 mg/dL). Plasma cytokine concentration revealed significant heat-induced activation of proinflammatory and antiinflammatory cascades. All patients exhibited systemic vasodilation requiring norepinephrine infusion, 4 of 5 patients required vigorous diuresis, and 3 of 5 required intubation for 24 to 36 hours because of pulmonary edema or somnolence, with full recovery. Average length of hospital stay was 5.4 days. Serial tumor measurements (1 patient withdrew) revealed a decrease (64.5%+/-18%) in tumor size in 2 patients, no change in 1, and enlargement in 1, with no 30-day mortality. Median survival after hyperthermia treatment was 172 days (range, 40 to 271 days). CONCLUSIONS: Venovenous perfusion-induced systemic hyperthermia is feasible and provides the following potential advantages for better tumoricidal effect: (1) homogeneous heating, and (2) a higher sustained temperature.

Veno-venous perfusion-induced systemic hyperthermia: case report with perfusion considerations.

Cancer cells are more susceptible to destruction by heat than are their normal counterparts. However, optimization of this hyperthermic susceptibility for selective cancer cell kill has been difficult to define and technically difficult to achieve. A whole-body hyperthermic technique veno-venous perfusion-induced systemic hyperthermia (VV-PISH) was designed in in vitro and in swine experiments to achieve selective hyperthermic cancer cell destruction. In this case report, VV-PISH is studied for its safety and therapeutic efficiency in a Food and Drug Administration (FDA) approved phase-I study, where hyperthermia is used to treat advanced (Stage III B or IV) lung cancer. VV-PISH, utilizing the ThermoChem HT system in an extracorporeal circuit, was used to induce hyperthermia to 42.5 degrees C sustained for 120 min. Cooling returned the body temperature to 37 degrees C. After completion of the treatment, the patient was transferred to the intensive care unit on a ventilator, norepinephrine and diuretics. The patient remained somnolent for 36 h, developed pulmonary congestion requiring an additional 48 h before extubation, was transferred to the intermediate unit on day 4 and discharged in good condition on day 8. He did experience hyperthermia-related shrinkage of his lung cancer; however, he succumbed 270 days after this treatment from further progression of this disease. Hyperthermia is not a benign therapy; management techniques have been developed that have ameliorated many of the problems associated with extremely high temperatures, but pathophysiology still exists. Using these techniques, VV-PISH can be safety implemented, albeit not without temporary sequelae and further hospitalization.

Regional perfusion abnormalities with phenylephrine during normothermic bypass.

BACKGROUND: Hypotension and vasopressors during cardiopulmonary bypass may contribute to splanchnic ischemia. The effect of restoring aortic pressure on visceral organ, brain, and femoral muscle perfusion during cardiopulmonary bypass by increasing pump flow or infusing phenylephrine was examined. METHODS: Twelve anesthetized swine were stabilized on normothermic cardiopulmonary bypass. After baseline measurements, including regional blood flow (radioactive microspheres), aortic pressure was reduced to 40 mm Hg by decreasing the pump flow. Next, aortic pressure was restored to 65 mm Hg either by increasing the pump flow or by titrating phenylephrine. The animals had both interventions in random order. RESULTS: At 40 mm Hg aortic pressure, perfusion to all visceral organs and femoral muscle, but not to the brain, was significantly reduced. Increasing pump flow improved perfusion to the pancreas, colon, and kidneys. In contrast, infusing phenylephrine (2.4 +/- 0.6 micrograms.kg-1.min-1) increased aortic pressure but failed to improve splanchnic perfusion, so that significant perfusion differences existed between the pump flow and phenylephrine intervals. CONCLUSIONS: Increasing systemic pressure during cardiopulmonary bypass with phenylephrine causes significantly lower values of splanchnic blood flow than does increasing the pump flow. Administering vasoconstrictors during normothermic cardiopulmonary bypass may mask substantial hypoperfusion of splanchnic organs despite restoration of perfusion pressure.

Increasing organ blood flow during cardiopulmonary bypass in pigs: comparison of dopamine and perfusion pressure.

OBJECTIVE: To determine whether low-dose dopamine infusion (5 micrograms/kg/min) during cardiopulmonary bypass selectively increases perfusion to the kidney, splanchnic organs, and brain at low (45 mm Hg) as well as high (90 mm Hg) perfusion pressures. DESIGN: Randomized crossover trial. SETTING: Animal research laboratory in a university medical center. SUBJECTS: Ten female Yorkshire pigs (weight 29.9 +/- 1.2 kg). INTERVENTION: Anesthetized pigs were placed on normothermic cardiopulmonary bypass at a 100-mL/kg/min flow rate. After baseline measurements, the animal was subjected, in random sequence, to 15-min periods of low perfusion pressure (45 mm Hg), low perfusion pressure with dopamine (5 micrograms/kg/min), high perfusion pressure (90 mm Hg), and high perfusion pressure with dopamine. Regional perfusion (radioactive microspheres) was measured in tissue samples (2 to 10 g) from the renal cortex (outer two-third and inner one-third segments), stomach, duodenum, jejunum, ileum, colon, pancreas, and cerebral hemispheres. MEASUREMENTS AND MAIN RESULTS: Systemic perfusion pressure was altered by adjusting pump flow rate (r2 = .61; p < .05). In the kidney, cortical perfusion pressure increased from 178 +/- 16 mL/min/100 g at the low perfusion pressure to 399 +/- 23 mL/min/100 g at the high perfusion pressure (p < .05). Perfusion pressure augmentation increased the ratio of outer/inner renal cortical blood flow from 0.9 +/- 0.1 to 1.2 +/- 0.1 (p < .05). At each perfusion pressure, low-dose dopamine had no beneficial effect on renal perfusion or flow distribution. Similar results were found in the splanchnic organs, where regional perfusion was altered by perfusion pressure but not by dopamine. In contrast, neither changing perfusion pressure nor adding low-dose dopamine altered blood flow to the cerebral cortex. CONCLUSIONS: These data indicate that the lower autoregulatory limits of perfusion to the kidneys and splanchnic organs differ from those limits to the brain during normothermic bypass. Selective vasodilation from low-dose dopamine was not found in renal, splanchnic, or cerebral vascular beds. Increasing the perfusion pressure by pump flow, rather than by the addition of low-dose dopamine, enhanced renal and splanchnic but not cerebral blood flows during cardiopulmonary bypass.

Endorphin mediation of mesenteric blood flow after endotoxemia in sheep.

BACKGROUND AND METHODS: The administration of endotoxin in small dosages to sheep results in an acute decrease followed by an increase in cardiac output. It has previously been determined that the initial decrease in output was the result of a reduction in blood flow to the mesenteric areas. These changes were associated with increased blood concentrations of beta endorphin. The present study was accomplished to determine if the systemic cardiovascular response to endotoxin could be affected by the administration of an opiate receptor-blocking agent. Female range sheep (n = 12) were prepared for chronic study by implantation of cardiopulmonary catheters and a flow probe on the cephalic mesenteric artery. Endotoxin (Escherichia coli, 1 microgram/kg) was administered to these animals. Half of the sheep were treated with naloxone (2 mg/kg + 2 mg/kg.hr), and the remainder with an equivalent volume of sodium chloride (0.9%). RESULTS: In untreated sheep, cardiac indices decreased by 15% to 20% (5.1 +/- 0.1 to 4.2 +/- 0.4 L/min.m2) between 0 and 1 hr and 2 and 5 hrs after endotoxin (4.5 +/- 0.2 L/min.m2), and then increased to a value 40% (7.2 +/- 0.6 L/min.m2) above baseline by 12 hrs. Flow in the cephalic mesenteric artery decreased in a pattern similar to the reduction in cardiac index (962 +/- 152 [time, T = 0] to 379 +/- 111 [T = 0.8] and 384 +/- 88 mL/min [T = 4.0], p less than .05) but did not increase to the same extent (1008 +/- 153 mL/min [T = 4.0], p greater than .05). There was a concomitant increase in the plasma beta-endorphin concentrations as the blood flow decreased (5 +/- 4 [T = 0] to 40 +/- 15 pg/mL [T = 0.8; untreated group], p less than .05; and 10 +/- 4 to 50 +/- 7 pg/mL [T = 0.8; naloxone-treated group], p less than .05). In the naloxone-treated group, the same pattern of cardiac output change was noted with endotoxin; however, reduction of mesenteric artery flow was only 30% (1118 +/- 129 to 908 +/- 122 mL/min, p less than .05) of the value seen in the untreated animals (962 +/- 152 to 379 +/- 111 mL/min, p less than .05). These changes in mesenteric blood flow were statistically significant from one another. As the cardiac output increased in the sheep treated with the opiate antagonist, mesenteric blood flows increased 20% above the baseline value (1391 +/- 199 mL/min, p less than .05). CONCLUSIONS: The decrease in cardiac output noted with endotoxin can be accounted for by the decrease in the blood flow in the cephalic mesenteric artery. This phenomenon can be attributed, at least in part, to the release of endorphins. There is both a vasodilation and constriction during endotoxemia in the ovine model.

Role of bradykinin in ovine endotoxemia.

We determined if the cardiopulmonary response to endotoxin (LPS) is mediated by bradykinin (BK). Sheep (n = 30) were prepared for chronic study with cardiopulmonary catheters, and chronic lung lymph fistulae. They were divided into the following study groups: A) BK infusion; B) LPS; C) LPS with angiotensin converting enzyme inhibitor (ACEI); D) ACEI alone; E) LPS with BK antagonist. Cardiac index and mean arterial pressure fell (6.9 +/- 0.4 to 5.3 +/- 0.3 L/min/m2 and 93 +/- 4 to 72 +/- 3 mmHg, respectively), and pulmonary lymph flow increased (10.5 +/- 3.0 to 17.8 +/- 4.3 ml/hr) during BK infusion. Addition of ACEI during BK infusion reduced the amount of BK necessary to induce a comparable response (125 to 2 micrograms/kg/hr). Administration of ACEI to LPS animals did not significantly alter their cardiopulmonary responses. BK antagonist did not change the response to LPS. Although the kallikrein-kinin pathway is believed to be activated during the septic response, our data do not lend support for the hypothesis that bradykinin is an important mediator of the cardiopulmonary changes.

The effect of propranolol on catecholamine clearance.

Normal subjects given propranolol increased their plasma t1/2 for infused isoproterenol from 2.68 to 6.25 minutes. Propranolol increased plasma norepinephrine (NE) levels only slightly. Propranolol increased the t1/2 of isoproterenol but not that of NE in men with autonomic nervous system degeneration. This suggests that propranolol acts on nonneuronal uptake-2 processes, rather than on uptake-1 mechanisms. alpha-Blockers slow uptake-1 and beta-blockers slow uptake-2 processes. When 27 subjects exercised, those who attained the highest plasma levels of the alpha- and beta-receptor agonist NE also had the briefest apparent t1/2 for NE. Adrenergic receptor blocking drugs slow catecholamine clearance. NE may stimulate its own clearance.

Thiopurine methyltransferase: structure-activity relationships for benzoic acid inhibitors and thiophenol substrates.

Twenty-seven substituted benzoic acids have been studied as inhibitors of partially purified human renal thiopurine methyltransferase (TPMT). Quantitative structure-activity relationship (QSAR) analysis resulted in the following equation: pI50 = 1.25( +/- 0.53)pi'3 + 0.73( +/- 0.38)MR3,4 + 2.92( +/- 0.39). In this equation pI50 is the -log of the concentration of compound that inhibits the enzyme activity by 50% (IC50);pi'3 is the relative hydrophobicity of the more hydrophobic of the two meta substituents; and MR3,4 is the molar refractivity of the more hydrophobic of the two meta substituents and of the para substituent on the phenyl ring. In addition, 14 substituted thiophenols were tested as substrates for the enzyme. All 14 thiophenols tested were excellent substrates with Km constants (0.8-7.8 microM) that were at least 2 orders of magnitude lower than those of any known thiopurine substrate for TPMT. However, there was no discernible relationship between the activities of thiophenol substrates and their physicochemical parameters. These results suggest that benzoic acid inhibitors of and thiophenol substrates for TPMT may interact with different sites on the enzyme.

Pressor response to beta-blocking drugs.

A patient with essential hypertension had a prolonged period of uncontrollable high blood pressure during therapy with the nonspecific beta-blocker nadolol. A subsequent challenge with the beta1-blocker atenolol caused a pressor response associated with diminished catecholamine release, impaired catecholamine clearance, loss of baroreflex response, and bradycardia. Beta-blocking drugs can lead to hypertension by causing fluid retention, reversal of catecholamine vasodilatation, or a direct pressor effect.

Thiopurine methyltransferase. Aromatic thiol substrates and inhibition by benzoic acid derivatives.

Thiopurine methyltransferase (TPMT) catalyzes the S-methylation of thiopurine and thiopyrimidine drugs. If potent TPMT inhibitors were available, studies of the regulation and properties of this drug-metabolizing enzyme would be facilitated. Each of a series of benzoic acid derivatives tested was found to inhibit purified human kidney TPMT. Concentrations required to inhibit TPMT by 50% ranged from 20 microM for 3,4-dimethoxy-5-hydroxybenzoic acid to 2.1 mM for acetylsalicylic acid. Inhibition was noncompetitive or mixed with respect to both S-adenosyl-L-methionine, the methyl donor for the enzyme, and 6-mercaptopurine, the methyl acceptor substrate. Preliminary structure-activity relationship analysis demonstrated that the benzoic acid structure was important for inhibitory activity, and that inhibition was enhanced by the addition of methoxy and/or phenolic hydroxyl groups to the ring. Quantitative structure-activity relationship analysis performed with additional benzoic acid derivatives showed that inhibitory activity could be modeled well by an equation that included the normal Hammett constant and a parameter, pi', related to lipophilicity. Several nonheterocyclic aromatic thiol compounds, including thiophenol and thiosalicylic acid, were discovered to be substrates for TPMT. Apparent Km constants for some of these aromatic thiol compounds were in the nanomolar range, several orders of magnitude lower than those of the thiopurines and thiopyrimidines previously thought to be the only substrates for TPMT. These observations suggested that "aryl thiol methyltransferase" might be a better name than "thiopurine methyltransferase" for this enzyme. Discovery of new classes of inhibitors and substrates for this important drug-metabolizing enzyme has implications for drug metabolism research and for clinical medicine.

Human kidney thiopurine methyltransferase. Purification and biochemical properties.

Thiopurine methyltransferase (TPMT) catalyzes the S-methylation of thiopurines and thiopyrimidines. Human kidney TPMT was purified over 300-fold and its biochemical properties were determined. TPMT was "soluble" and had a molecular weight of approximately 36,000 daltons as estimated by gel filtration chromatography. The pH optimum of the purified TPMT was 6.7. "True" Km values for 6-mercaptopurine (6-MP) and S-adenosyl-L-methionine (SAM), the two cosubstrates for the reaction, were 0.30 mM and 2.7 microM respectively. "Apparent" Km values for 6-thioguanine and 2-thiouracil, two other methyl acceptor substrates, were 0.55 and 2.0 mM respectively. Aliphatic thiol compounds were either poor substrates for TPMT or were not methylated. S-Adenosyl-L-homocysteine was a competitive inhibitor of TPMT when the varied substrate was SAM, and 6-methylmercaptopurine was a noncompetitive inhibitor with respect to 6-MP. Purified TPMT was neither activated nor inhibited by 1 mM Ca2+ or Mg2+, but exposure to reagents such as N-ethylmaleimide and ethacrynic acid that interact with sulfhydryl groups inactivated the enzyme. Tropolone inhibited TPMT with a Ki of approximately 0.85 mM. Finally, human kidney TPMT activity could be distinguished from human kidney thiol methyltransferase (EC 2.1.1.9) activity on the basis of subcellular distribution, substrate specificity, kinetic characteristics and differential sensitivity to inhibitors.

Rat phenol sulfotransferase. Assay procedure, developmental changes, and glucocorticoid regulation.

Phenol sulfotransferase (PST) catalyzes the sulfate conjugation of phenolic monoamines and phenolic drugs. It has been difficult to measure PST activity in tissue homogenates accurately because of the presence of potent endogenous PST inhibitors. Optimal conditions were determined for the assay of rat PST in very dilute tissue homogenates. These conditions negated the effects of endogenous enzyme inhibitors. Apparent Km values for 3-methoxy-4-hydroxyphenylglycol, the sulfate acceptor substrate used, were 0.15, 0.14, and 0.02 mM for liver, kidney, and brain homogenates respectively. Apparent Km values in the same tissues for 3'phosphoadenosine-5'phosphosulfate, the sulfate donor, were 0.11, 0.07, and 0.07 microM respectively. Rat PST activity expressed per mg protein increased 6.3-fold in the liver, 6.6-fold in the brain, and did not change in the kidney between birth and 10 weeks of age. There was a 5-fold increase in kidney PST activity in both adrenalectomized and sham-operated Sprague-Dawley rats after treatment with dexamethasone (7 mumoles/kg daily for 3 days). Brain enzyme activity was unchanged and liver PST activity increased only 41% during 72 hr of daily treatment with dexamethasone. Basal enzyme activities in all three tissues were no different in adrenalectomized and sham-operated animals. The increase in rat kidney PST activity in response to dexamethasone was dose dependent, and treatment of animals with cycloheximide, a protein synthesis inhibitor, blocked the elevation of kidney PST activity after dexamethasone. Treatment of eight inbred and two outbred rats strains with dexamethasone resulted in striking increases in renal PST, smaller increases in liver PST, and no changes in brain enzyme activity in all ten strains.

Catecholamine-induced hyperglycemia in dogs: independence from alterations in pancreatic hormone release.

Although isoproterenol is a very effective hyperglycemic agent in dogs, other species such as rats, baboons and man are resistant to this effect. In each of these species catecholamines exert pronounced effects on insulin and glucagon release from the pancreas. In man, baboons, and rats catecholamine-induced alterations in pancreatic hormone release indirectly influence the hyperglycemic response to these amines: glucagon release supports and insulin release limits hyperglycemic responses. In contrast, the present study demonstrates that in dogs catecholamine-induced hyperglycemic responses are relatively independent of concurrent alterations in pancreatic hormone release. In dogs isoproterenol produces hyperglycemia equal to or greater than responses to epinephrine despite large increases in insulin release produced by isoproterenol. Moreover, catecholamine-induced hyperglycemia is not significantly altered when insulin and glucagon release are blocked with somatostatin.

Comparative metabolic and cardiovascular effects of carbuterol, isoproterenol, metaproterenol and salbutamol in the baboon.

The metabolic and cardiovascular responses to two bronchiolar selective beta-adrenergic drugs, carbuterol (CAR) and salbutamol (SAL), were compared with isoproterenol (ISO) and metaproterenol (MET) in fasted, anesthetized baboons. ISO was more active than the selective beta-adrenergic drugs in elevating plasma levels of glucose, lactate, free fatty acids, insulin, and glucagon. Moreover, ISO was more active in increasing heart rate and respiratory rate and in depressing diastolic blood pressure. Although ISO was shown to have greater activity than CAR, MET, and SAL, the bronchiolar selective drugs (CAR and SAL) did produce significant changes in plasma levels of metabolic substrates and pancreatic hormones and in cardiovascular measurements at higher dose rates.

The influence of endogenous glucagon release on hyperglycemic responses to catecholamines in normal fed and diabetic rats.

The present study provides evidence that changes in glucagon secretion are influential in determining the hyperglycemic activity of catecholamines in normal and diabetic rats. In normal fed rats, epinephrine (EPI) stimulated large increments in glucagon release and inhibited insulin secretion. In contrast, the modest hyperglycemic activity of isoproterenol (ISO) in normal fed rats correlated with its weak glucagon-releasing activity and its strong insulin-releasing activity. In alloxan-diabetic rats, the augmented hyperglycemic response to ISO was accompanied by larger increments in plasma glucagon levels than the catecholamine produced in normal fed rats. When glucagon release was inhibited by a concurrent infusion of somatostatin, the hyperglycemic responses of normal fed rats to EPI were reduced by approximately 67%. ISO-induced hyperglycemia in alloxan-diabetic rats was even more sensitive to inhibition by somatostatin since this response was reduced by approximately 90% when glucagon release was inhibited by somatostatin. These findings indicate that more than half of the hyperglycemic response to EPI in normal fed rats and nearly all of the hyperglycemia produced by ISO in diabetic rats result from increased glucagon release. Moreover, the impotence of ISO as a hyperglycemic agent in normal fed rats is probably due to insulin release which tends to suppress glucagon release.

Catecholamine-induced changes in plasma glucose, glucagon and insulin in rabbits: effects of somatostatin.

The present study was conducted to determine if glucagon release is involved in the hyperglycemic response to epinephrine and isoproterenol in the fasted and fed, unanesthetized rabbit. Epinephrine produced dose-related increases in plasma glucose and glucagon levels in fed and fasted rabbits whereas isoprotereol produced modest hyperglycemia without hyperglucagonemia. Infusion of somatostatin suppressed epinephrine-induced glucagon release and this was correlated with a 50% reduction in the hyperglycemic response. These data suggest that epinephrine-induced glucagon release is the primary reason for the difference in hyperglycemic activity between epinephrine and isoproterenol in the unanesthetized rabbit.