Distinct clinical and laboratory activity of two recombinant interleukin-2 preparations.
Interleukin-2 (IL-2) is a potent lymphokine that activates natural killer cells, T cells, and other cells of the immune system. Several distinct recombinant human IL-2 preparations have shown antitumor activity, particularly for renal cell cancer and melanoma. Somewhat distinct immune and clinical effects have been noted when different IL-2 preparations have been tested clinically; however, the regimens and doses used were not identical. To compare these more directly, we have evaluated two clinical recombinant IL-2 preparations in vitro and in vivo using similar regimens and similar IUs of IL-2. We used the Food and Drug Administration-approved, commercially available Chiron IL-2 and the Hoffmann LaRoche (HLR) IL-2 supplied by the National Cancer Institute. Using equivalent IUs of IL-2, we noted quantitative differences in vitro and in vivo in the IL-2 activity of these two preparations. In patients receiving comparable IUs of the two preparations, HLR IL-2 induced the release of more soluble IL-2 receptor alpha into the serum than Chiron IL-2. In addition, more toxicities were noted in patients receiving 1.5 x 10(6) IU of HLR IL-2 than were seen in patients treated with 1.5 x 10(6) or even 4.5 x 10(6) IU of Chiron IL-2. These toxicities included fever, nausea and vomiting, and hepatic toxicity. In vitro proliferative assays using IL-2-dependent human and murine cell lines indicated that the IU of HLR IL-2 was more effective than Chiron IL-2 at inducing tritiated thymidine incorporation. Using flow cytometry, we also found quantitative differences in the ability of these two preparations to bind to IL-2 receptors. These findings indicate that approximately 3-6 IU of Chiron IL-2 are required to induce the same biological effect as 1 IU of HLR IL-2. (+info)
Efficacy of ampicillin plus ceftriaxone in treatment of experimental endocarditis due to Enterococcus faecalis strains highly resistant to aminoglycosides.
The purpose of this work was to evaluate the in vitro possibilities of ampicillin-ceftriaxone combinations for 10 Enterococcus faecalis strains with high-level resistance to aminoglycosides (HLRAg) and to assess the efficacy of ampicillin plus ceftriaxone, both administered with humanlike pharmacokinetics, for the treatment of experimental endocarditis due to HLRAg E. faecalis. A reduction of 1 to 4 dilutions in MICs of ampicillin was obtained when ampicillin was combined with a fixed subinhibitory ceftriaxone concentration of 4 micrograms/ml. This potentiating effect was also observed by the double disk method with all 10 strains. Time-kill studies performed with 1 and 2 micrograms of ampicillin alone per ml or in combination with 5, 10, 20, 40, and 60 micrograms of ceftriaxone per ml showed a > or = 2 log10 reduction in CFU per milliliter with respect to ampicillin alone and to the initial inoculum for all 10 E. faecalis strains studied. This effect was obtained for seven strains with the combination of 2 micrograms of ampicillin per ml plus 10 micrograms of ceftriaxone per ml and for six strains with 5 micrograms of ceftriaxone per ml. Animals with catheter-induced endocarditis were infected intravenously with 10(8) CFU of E. faecalis V48 or 10(5) CFU of E. faecalis V45 and were treated for 3 days with humanlike pharmacokinetics of 2 g of ampicillin every 4 h, alone or combined with 2 g of ceftriaxone every 12 h. The levels in serum and the pharmacokinetic parameters of the humanlike pharmacokinetics of ampicillin or ceftriaxone in rabbits were similar to those found in humans treated with 2 g of ampicillin or ceftriaxone intravenously. Results of the therapy for experimental endocarditis caused by E. faecalis V48 or V45 showed that the residual bacterial titers in aortic valve vegetations were significantly lower in the animals treated with the combinations of ampicillin plus ceftriaxone than in those treated with ampicillin alone (P < 0.001). The combination of ampicillin and ceftriaxone showed in vitro and in vivo synergism against HLRAg E. faecalis. (+info)
Phase I-II study of gemcitabine and fluorouracil as a continuous infusion in patients with pancreatic cancer.
PURPOSE: To determine the maximum-tolerated dose (MTD), dose-limiting toxicities, and efficacy of gemcitabine combined with fluorouracil (5-FU) in patients with pancreatic cancer. PATIENTS AND METHODS: Patients with measurable, locally advanced, nonresectable or metastatic pancreatic cancer were candidates for the study. 5-FU was given via protracted venous infusion (PVI) at a fixed dosage of 200 mg/m2/d, and gemcitabine was administered weekly for 3 consecutive weeks every 4 weeks. The initial dose of gemcitabine was 700 mg/m2 and was escalated in increments of 100 mg/m2/wk until the appearance of severe toxicity. Measurements of efficacy included the following: response rate; clinical benefit response, which is a composite measurement of pain, performance status, and weight loss; time to disease progression; and survival. RESULTS: Twenty-six patients received a total of 109 courses. Dose-limiting toxicity, which consisted of grade 4 neutropenia with fever (one patient) and grade 4 thrombocytopenia (one patient), was observed in two of three patients treated with 1,100 mg/m2/wk of gemcitabine. On the basis of these results, the MTD of gemcitabine with 5-FU via PVI on this schedule was 1,000 mg/m2. Sixteen patients developed grade 3-4 neutropenia, and three patients developed grade 3-4 thrombocytopenia. Grade 3-4 nonhematologic toxicity consisted of diarrhea (two patients) and cutaneous toxicity, asthenia, edema, mucositis, and nausea and vomiting (one patient each). The delivered dose-intensity of gemcitabine was similar at the 1,000 mg/m2 dose level (599 mg/m2/wk) as at the 900 mg/m2 (601 mg/m2/wk) dose level. For this reason, the recommended dose of gemcitabine for phase II evaluation on this schedule was 900 mg/m2. Five patients had objective responses (one complete response and four partial responses; response rate, 19.2%; 95% confidence interval [CI], 6.5 to 39.3), and 10 patients had improvement of disease-related symptoms (45%; 95% CI, 24 to 67). After a median follow-up of 17.7 months (range, 7.8 to 24.8 months), the median progression-free survival and overall survival times were 7.4 months (95% CI, 3.3 to 11.4) and 10.3 months (95% CI, 8.1 to 12.5), respectively. CONCLUSION: The MTD of gemcitabine when combined with 5-FU via PVI on this schedule was 1,000 mg/m2/ wk; however, on the basis of administered dose-intensity, the recommended dose for additional investigation is 900 mg/m2. This combination chemotherapy regimen was well tolerated and showed promising antitumor activity in the treatment of pancreatic cancer. (+info)
The effects of vapreotide, a somatostatin analogue, on gastric acidity, gallbladder emptying and hormone release after 1 week of continuous subcutaneous infusion in normal subjects.
AIMS: Somatostatin analogues (e.g. vapreotide) are used for treatment of acromegaly, endocrine tumours and variceal bleeding. The pharmacodynamic effects of vapreotide have, however, not been documented in the gastrointestinal tract. The aim of this study was to investigate the effects of continuous vapreotide administration on gastric acidity, gallbladder contraction and hormone release. METHODS: Ten healthy males participated in this randomised, placebo-controlled, double-blind, crossover trial. A constant vapreotide (or placebo) infusion (1.5 mg day(-1) s.c.) was given for 7 days with a portable pump. Intragastric pH was monitored on days 2 and 7. Gallbladder volume was sonographically assessed and the maximal ejection fraction was calculated. In addition basal and postprandial plasma levels of gastrin and cholecystokinin (CCK) were measured. RESULTS: After an initial increase in the median 24 h intragastric pH to a value of 2.6 on day 2, vapreotide's effect on pH decreased: (day 7: median pH=1.9; respective placebo values were 1.7 and 1.5). On the same days with vapreotide treatment, gallbladder contraction and plasma levels of CCK were reduced; maximal ejection fractions after meal stimulation were 18% and 20% (respective placebo values were 57% and 62%). Plasma gastrin levels were not changed with vapreotide treatment. CONCLUSIONS: The short lasting effect of vapreotide on intragastric acidity suggests a down-regulation of somatostatin receptors during treatment. The lack of effect on gastrin indicates that the effects on gastric pH are not mediated by gastrin. Constant vapreotide infusion (but not placebo) reduced gallbladder contraction suggesting a long-lasting effect on biliary function. (+info)
Self-intoxication with morphine obtained from an infusion pump.
A 36-year-old Caucasian male was found unresponsive by his wife. He had white foam around his mouth and was pronounced dead shortly thereafter. He had a history of back pain and was treated with intrathecal morphine because of his previous addiction to oral opiate medications. Because of crimping of the pump catheter, it was replaced 4 days before his death. Toxicological findings included urine screen positive for amitriptyline, nortriptyline, opiates, hydrocodone metabolites, ibuprofen, acetaminophen, caffeine, nicotine, and metabolite. Drug concentrations were as follows: blood, 0.260 mg/L amitriptyline, 0.160 mg/L nortriptyline, 0.460 mg/L unconjugated morphine, and 0.624 mg/L total morphine; vitreous humor, 0.034 mg/L unconjugated morphine and 0.080 mg/L total morphine; and cerebrospinal fluid, 0.099 mg/L unconjugated morphine and 0.095 mg/L total morphine. Shortly after death, the volume of the residual pump reservoir was only 8 mL instead of the expected 17 mL. Testing by the FDA showed that the pump was functional. The residual content of the pump accounted for only 230 mg instead of the expected 488 mg. The high blood-morphine concentrations did not correlate with the intrathecal infusion dose. The symptoms were consistent with opiate overdose, possibly by injection of morphine withdrawn from the pump reservoir. The cause of death was determined to be fatal morphine self-intoxication, and the manner of death was accidental. This case is intended to alert regulatory agencies, pain management health professionals, pathologists, and toxicologists to the abuse potential of one of the newer analgesic-delivery systems. (+info)
Glutamate augments retrovirus-induced immunodeficiency through chronic stimulation of the hypothalamic-pituitary- adrenal axis.
The mechanisms for activating the hypothalamic-pituitary-adrenal (HPA) axis and the roles glucocorticoids play in the pathogenesis of chronic infectious disease are largely undefined. Using the LP-BM5 model of retrovirus-induced immunodeficiency, we found alterations in HPA axis function, manifested as an increase in circulating levels of adrenocorticotropic hormone and corticosterone, beginning after only 3 mo of infection. These changes occurred contemporaneously with a shift in the profile of circulating cytokines from a Th1-dominant (IFN-gamma) to Th2-dominant (IL-4, IL-10) phenotype. No significant changes in either circulating IL-1beta, IL-6, or TNF-alpha levels were observed in infected mice. Administering the N-methyl-D-aspartate receptor antagonist MK-801 to infected mice normalized plasma adrenocorticotropic hormone and corticosterone levels, indicating that glutamate was a major activator of the HPA axis. Moreover, MK-801 treatment of late-stage mice also reversed the type 1 to type 2 cytokine shift to a degree comparable or superior to treatment with the glucocorticoid receptor antagonist RU-486. These findings indicate that HPA axis activation during LP-BM5 retrovirus infection is mediated by the chronic hyperactivation of glutamatergic pathways in the hypothalamus. Through this mechanism, the degree of peripheral immunodeficiency observed in the late-stage disease is profoundly augmented. (+info)
Enhancement of locomotor activity and conditioned reward to cocaine by brain-derived neurotrophic factor.
The mesolimbic dopamine (DA) system has been implicated in drug reward, locomotor sensitization, and responding for reward-related stimuli [termed conditioned reinforcers (CR)]. Here, we investigated the effect of brain-derived neurotrophic factor (BDNF), which enhances the survival and function of dopaminergic neurons, on stimulant-induced locomotor sensitization and responding for CR. In experiment 1, BDNF was infused into the nucleus accumbens (NAc) or ventral tegmental area over 2 weeks via chronically implanted minipumps (1-2.5 microgram/d), and the psychomotor stimulant effects of cocaine (5-15 mg/kg, i.p.) were studied. We found that BDNF enhanced the initial stimulant effects of cocaine and seemed to facilitate the development of sensitization to repeated cocaine doses. In experiment 2, we studied the effects of intra-NAc BDNF infusions on responding for CR. BDNF-treated rats showed twice as many CR responses compared with controls when saline was first administered. BDNF enhanced responding on the CR lever more than four times that seen in control animals after a cocaine injection (10 mg/kg, i.p.). The enhanced response to cocaine in BDNF-treated animals persisted for more than a month after the BDNF infusions had stopped, indicating long-lasting changes in the mesolimbic DA system caused by BDNF administration. In experiment 3, we examined locomotor sensitization to cocaine in heterozygous BDNF knock-out mice and found that the development of sensitization was delayed compared with wild-type littermates. These results demonstrate the profound effects of BDNF on the enhancement of both cocaine-induced locomotion and facilitation of CR and suggest a possible role for BDNF in long-term adaptations of the brain to cocaine. (+info)
Comparison of recovery of propofol and methohexital sedation using an infusion pump.
Two sedative anesthetic agents administered by an infusion pump were compared during third molar surgery. Forty American Society of Anesthesiologists (ASA) class I or II volunteers were randomly allocated to two groups. All subjects received supplemental oxygen via a nasal hood, fentanyl (0.0007 mg/kg intravenous [i.v.] bolus), and midazolam (1 mg/2 min) titrated to effect. Patients then received either 0.3 mg/kg of methohexital or 0.5 mg/kg of propofol via an infusion pump. Upon completion of the bolus, a continuous infusion of 0.05 mg/kg/min methohexital or 0.066 mg/kg/min propofol was administered throughout the procedure. Hemo-dynamic and respiratory parameters and psychomotor performance were compared for the two groups and no significant differences were found. The continuous infusion method maintained a steady level of sedation. Patients receiving propofol had a smoother sedation as judged by the surgeon and anesthetist. (+info)