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Biomedical subjects

K Padavic-Shaller

Publications and source records attributed to K Padavic-Shaller.

8 recordsLinked to original sources
PubMed1997

Simultaneous 3D NMR spectroscopy of proton-decoupled fluorine and phosphorus in human liver during 5-fluorouracil chemotherapy.

Simultaneous acquisition of 1H-decoupled 31P and 19F 3D CSI is demonstrated in the liver of a patient undergoing 5-fluorouracil chemotherapy. Both 31P and 19F shared the same voxel size (64 or 27 ml), bi-level 1H-decoupling and 0.35 s TR. The measurements were done in a 1.5 Tesla clinical imager with three radio-frequency (RF) channels and a triple-tuned surface-coil. The overall MRI and MRS examination time was under 90 min. Simultaneous acquisition of 31P and 19F permits localized study of the influence of hepatic metabolism on the uptake and catabolism of fluoropyrimidine drugs without extra measurement time or higher SAR.

Absorption↗
PubMed1996

Molar quantitation of hepatic metabolites in vivo in proton-decoupled, nuclear Overhauser effect enhanced 31P NMR spectra localized by three-dimensional chemical shift imaging.

Proton decoupling and nuclear Overhauser effect (NOE) enhancement significantly improve the signal-to-noise ratio and enhance resolution of metabolites in in vivo 31P MRS. We obtained proton-decoupled, NOE-enhanced, phospholipid-saturated 31P spectra localized to defined regions within the normal liver using three-dimensional chemical shift imaging. Proton-decoupling resulted in the resolution of two major peaks in the phosphomonoester (PME) region, three peaks in the phosphodiester (PDE) region and a diphosphodiester peak. In order to obtain molar quantitation, we measured the NOE of all hepatic phosphorus resonances, and we corrected for saturation effects by measuring hepatic metabolite T1 using the variable nutation angle method with phase-cycled, B1-independent rotation, adiabatic pulses. After corrections for saturation effects, NOE enhancement, B1 variations and point spread effects, the following mean concentrations (mmol/l of liver) (+/-SD) were obtained: [PME1] = 1.2 +/- 0.4, [PME2 + 2,3-DPG] = 1.1 +/- 0.1, [Pi + 2,3-DPG] = 2.8 +/- 0.5, [GPEth] = 2.8 +/- 0.7, [GPChol] = 3.5 +/- 0.6 and [beta-NTP] = 3.8 +/- 0.3. T1 and NOE enhancement were strongly correlated (r = 90), and indicated that the fractional contribution of 1H-31P dipolar relaxation to total 31P relaxation is minimal for NTPs, moderate for PMEs and high for PDEs in liver. Proton-decoupling and NOE enhancement permit one to obtain more information about in vivo metabolism of liver than previously available and should enhance the utility of 31P MRS for the study of hepatic disorders.

Adult↗
PubMed1995

Phase I study of sequentially administered recombinant tumor necrosis factor and recombinant interleukin-2.

The purposes of this study were to determine the maximally tolerated dose (MTD) of IL-2 when sequentially administered following TNF (at its MTD), to identify any unique toxicities, and determine the immunomodulatory effects of this combination. Patients with metastatic cancer were treated with 160 micrograms/ml rTNF by rapid i.v. infusion for 5 days, followed by rIL-2 therapy daily at doses up to 18 x 10(6) IU/m2/day for 5 days and 6 x 10(6) IU/m2/day for 7 days. Cycles were repeated at 3- or 4-week intervals until progressive disease or unacceptable toxicity developed. Fifteen patients received 46 cycles of therapy (range 1-8, median 3). Major toxicities included hypotension, weight loss, and decreased performance status comparable to that reported with rIL-2 alone. No novel toxicities were identified. Two of 14 patients who received two cycles of therapy had objective responses (1 complete, 1 partial). Both occurred in patients with malignant melanoma, lasted 30 and 75 weeks, respectively, and included a complete response in liver metastasis. Dosage reductions of IL-2 were necessary for 3 patients over 11 treatment cycles (23%), and rTNF in 1 patient for 1 cycle (2%). The MTD of 5-day infusional rIL-2 was determined at 18 x 10(6) IU/m2/day. rTNF did not augment natural killer/lymphokine-activated killer activities beyond that commonly seen with IL-2 infusions. We conclude that full doses of rTNF can be combined with escalating rIL-2 infusions in an outpatient setting without additive toxicity and with clinical activity in patients with malignant melanoma.

Adult↗
PubMed1993

Phase II multicenter evaluation of prolonged murine monoclonal antibody 17-1A therapy in pancreatic carcinoma.

Twenty-eight patients with unresectable, measurable pancreatic carcinoma and Eastern Oncology Cooperative Group (ECOG) performance status of 0 or 1 were treated with the murine monoclonal antibody 17-1A, planning to administer 500 mg i.v. three times weekly for 8 weeks. Treatment was well tolerated, with an 18% incidence (five patients) of hypersensitivity reactions. All hypersensitivity episodes occurred in the first 3 weeks of therapy and required treatment discontinuation. Six patients required early discontinuation of therapy due to symptomatic progressive disease and one patient was removed from the study due to a protocol violation. Sixteen patients received the full course of 12 g of antibody. One patient has exhibited a durable partial response. Antibody pharmacokinetics were determined in five patients. In four patients peak 17-1A levels averaged 100 micrograms/ml with mean harmonic t1/2 of 16.8 h in a one-compartment model. Neither pretreatment nor posttreatment levels of circulating 17-1A changed significantly during the 8 weeks of treatment. This study demonstrates the feasibility and acceptable toxicity of repetitive dosing with an unconjugated murine monoclonal antibody. The lack of efficacy of treatment suggests that factors other than prolonged exposure of tumor and cytotoxic effector cells to murine antibody are required for successful antibody therapy of pancreatic cancer.

Aged↗
PubMed1991

Phase I evaluation of combination therapy with interleukin 2 and gamma-interferon.

Recombinant interleukin 2 (IL-2) is a potent inducer of lymphokine-activated killer (LAK) activity directed against autologous and allogeneic tumors; these effects are mediated by CD3-negative, CD56-positive, and CD16-positive lymphocytes. Although IL-2 therapy has been associated with clinical responses, particularly in patients with renal cell carcinoma and melanoma, these responses have occurred with high, toxic doses of this cytokine. Since gamma-interferon (IFN-gamma) potentiates LAK activity in vitro and in animal models, we initiated a dose-escalating Phase I trial of IFN-gamma and IL-2 in patients with advanced cancer. Patients were treated three times weekly (Monday, Wednesday, and Friday) for 6 weeks with bolus injections of IL-2; each dose was preceded 2 h earlier by a s.c. injection of IFN-gamma. Patients were treated with IFN-gamma at 0.01, 0.05, 0.1, or 0.25 mg/m2/dose. At each IFN-gamma dose, cohorts of at least three patients were treated with IL-2 at 1, 2.5, 5.0, or 7.5 x 10(6) Cetus units/m2 dose. Patients with clinical responses continued therapy three times weekly, while those with stable disease at 6 weeks were then treated twice weekly. A total of 41 patients were treated, all with Eastern Cooperative Oncology Group performance status 0 or 1. All patients were evaluable for toxicity. Dose-limiting toxicities were cumulative fatigue and constitutional symptoms. One documented transmural myocardial infarct occurred. The maximally tolerated dose combination, based on analysis of IL-2 dose intensity, was 0.1 mg IFN-gamma/m2 and 7.5 x 10(6) Cetus units IL-2/m2 per dose. Two partial responses and two minor responses were observed. Treatment was not associated with dose-associated changes in peripheral blood lymphocyte phenotype, but there was a trend favoring IFN-gamma dose-associated rises in IL-2 induction of natural killer and LAK activity by treated patients' lymphocytes. Analysis of the cumulative effects of therapy on induction of natural killer and LAK activity by measurement of the median area under the curve of activation showed clear evidence of IFN-gamma and IL-2 dose-associated changes. The IL-2 dose effects on cell lysis were monotone, while the optimal IFN-gamma dose appeared to be 0.1 mg/m2/dose, with a bell-shaped dose-response curve described previously for other effects of this cytokine. Using this novel statistical method of evaluating the biological effects of treatment, the optimal biological dose was identical to the maximally tolerated dose.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1991

Phase II study of weekly 5-fluorouracil, cisplatin and vinblastine in advanced non-small cell lung cancer.

The scheduling of chemotherapeutic agents may be important in optimising their antitumour actions. This has been explored in non-Hodgkin lymphoma, osteogenic sarcoma and bladder cancer with improved results using intensive, weekly dosing schemas. We began a phase II study of cisplatin, 5-fluorouracil and vinblastine in non-small cell lung cancer (NSCLC) on a weekly schedule. 38 patients with advanced or metastatic NSCLC were entered; 32 are evaluable for response. 11 patients were treated with 5-fluorouracil 1.5 g/m2 and vinblastine 4 mg/m2 by 24-h continuous infusion, and cisplatin 30 mg/m2 over 30 min, 6-8 h after the start of the infusion. Because of prohibitive myelotoxicity, the next 27 patients received 5-fluorouracil 1.2 g/m2 and vinblastine 3 mg/m2. None had had prior chemotherapy while 6 had had previous radiation therapy. Myelosuppression was the predominant toxic effect. Other side-effects included neuropathy, diarrhoea, mucositis, nausea and vomiting. 32 patients are evaluable for response: there have been 14 partial remissions (44%). Responses have occurred chiefly in lung and lymph nodes. The median survival on this study is 7 months, and responders did not live longer than non-responders. While this regimen is well tolerated by the majority of patients and has a response rate comparable to other active regimens identified in single institution studies, survival does not appear to be enhanced. We conclude that the schedule manipulation described here does not enhance the therapeutic index of these drugs in NSCLC.

Adult↗
PubMedDate not supplied

Phospholipid metabolites in 1H-decoupled 31P MRS in vivo in human cancer: implications for experimental models and clinical studies.

The use of 31P MRS in clinical cancer research has been hampered by both poor anatomic localization of spectra and poor resolution of overlapping signals. We found that accurate localization using 3D chemical shift imaging and improved resolution using 1H-decoupling and nuclear Overhauser-enhancement (NOE) increased signal-to-noise and permitted resolution of separate components within phosphomonoester (PME) and phosphodiester (PDE) regions. Fifty-three cancers of different types (lymphoma, sarcoma, adenocarcinoma) had the following common features: (1) phosphoethanolamine the dominant PME; (2) glycerophosphoethanolamine and -choline rarely detected; (3) a broad PDE signal probably from membrane phospholipids; and(4) prominent nucleoside triphosphates. 1H-decoupling with NOE-enhancement permitted us to obtain new information about in vivo metabolism in human cancers; generate new hypotheses and help guide development of experimental models appropriate to test them; and provide a firm basis with which to examine clinical uses of 31P MRS.

Humans↗