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Biomedical subjects

F Ostroy

Publications and source records attributed to F Ostroy.

10 recordsLinked to original sources
PubMed1985

A phase I trial of ametantrone acetate (NSC-287513).

Ametantrone acetate is an intensely blue anthracenedione undergoing clinical trials in man. In this Phase I study, 20 patients received 39 courses of drug as a single IV dose given daily for five days and repeated every three weeks (21 days). Dosage escalations proceeded from 15 mg/m2 to 35 mg/m2. Predictable and reversible leukopenia was the dose limiting toxicity. One previously untreated patient with renal cell carcinoma metastatic to the lungs and right arm experienced a partial response of 51 days duration. Nine patients had pharmacokinetic studies performed during the study. Ametantrone was extensively distributed (apparent volume of distribution, 26.3 l/m2) and demonstrated a short half-life (harmonic mean half-life, 0.38 hour). The maximum tolerated dose in this study was 35 mg/m2. Recommended doses for Phase II trials are 30 mg/m2 in good risk patients and 25 mg/m2 in poor risk patients. Because of the partial response seen in one patient with renal cell carcinoma, Phase II trials should include this tumor category in order to better define the activity of ametantrone in this disease. In addition, since the total amount of drug that could be given to patients receiving the five day schedule (125-150 mg/m2) was approximately the same amount that could be administered as a single dose (140 mg/m2), it would appear that the only advantage of the daily times five day dosage schedule would be in the lower incidence of bluish skin discoloration.

Adult↗
PubMed1985

Phase I trial of misonidazole (NSC#261037) plus cyclophosphamide in solid tumors.

Misonidazole, a hypoxic cell sensitizer, enhances the antitumor effects of cyclophosphamide in preclinical studies. Several studies also showed increased cytotoxicity for normal tissues. We undertook a phase I study of this combination. The regimen consisted of oral administration of misonidazole at one of two dose levels, 1 g/m2 and 2 g/m2, followed by an intravenous (IV) injection of cyclophosphamide four hours later. The cycle was repeated every twenty-one days. The dose of misonidazole remained constant for each regimen, but the dose of cyclophosphamide ranged from 0.4 g/m2 to 1.3 g/m2. Thirty-eight trials in 35 patients with advanced solid tumors were considered evaluable. Dose-limiting toxicity was granulocytopenia at 1 g/m2 of cyclophosphamide without significant thrombocytopenia or anemia. Peripheral neuropathy was negligible. Two patients received cumulative doses of 8 and 16 g/m2 of misonidazole without neurotoxicity. One patient developed hemorrhagic cystitis. Nausea and vomiting was mild to moderate. Possible evidence of tumor stabilization was seen in three patients, and one patient had a mixed response. The mean serum half-life for misonidazole was 11.3 hours (range, 8.4 to 20.0) and for cyclophosphamide 8.3 hours (range, 3.2 to 15.5), both within the previously reported ranges. In conclusion, it appears that this combination is well tolerated and that misonidazole does not significantly potentiate myelotoxicity caused by cyclophosphamide or alter its pharmacokinetics. The recommended starting doses for misonidazole and cyclophosphamide in phase II trials using this schedule of administration should be 2 g/m2 and 1 g/m2, respectively, with escalation for cyclophosphamide to individual tolerance.

Adult↗
PubMed1980

Clinical pharmacology of intermediate-dose oral methotrexate.

The clinical pharmacology of intermediate-dose oral methotrexate (MTX) was studied in nine patients receiving 18 courses of treatment. Serum and urine MTX concentrations were measured by means of a competitive protein binding assay after oral aqueous solution (3 courses), 50-mg tablets (13 courses) or IV drug (2 courses) had been administered in four doses of 100 mg/m2 at 6-h intervals or in four doses of 200 mg/m2 at 6-h intervals and followed by citrovorum factor rescue. Levels above 150 ng/ml (3.3 x 10(-7) M) were maintained throughout all treatment cycles, with rapid disappearance of drug after the last dose. A 100% increase in administered dose resulted in only a 42% increase in the concentration-time level. Methotrexate was absorbed well from both aqueous solutions and 50-mg tablets, but serum levels after 50-mg tablets were only 20% of those achieved after IV administration. We conclude that significant serum MTX concentrations can be achieved for prolonged periods of time after oral administration of intermediate doses, but that the proportion of drug absorbed is much less than is seen with lower doses.

Administration, Oral↗
PubMed1979

Ferrocyanide staining of transferrin and ferritin-conjugated antibody to transferrin.

To evaluate the ultrastructural distribution of transferrin on the surface of L1210 ascites tumor cells, we used ferrocyanide to stain ferric iron (Prussian blue reaction) in transferrin, as well as in ferritin conjugated to antibody that was immunologically attached to the transferrin. Small deposits averaging 5 nm in diameter identified transferrin iron, whereas large cuboidal deposits averaging 50 nm in diameter stained ferritin conjugated-antibody that was bound to both transferrin and apotransferrin on the cell surface. The ability of transferrin to deliver iron to ascites tumor cells was confirmed by kinetic studies of transferrin labeled with 59Fe and 125I. These preliminary results are consistent with release of transferrin iron at the cell surface and demonstrate additional uses for ferrocyanide in ultrastructural cytochemical techniques.

Animals↗
PubMed1979

Effect of hypoxia on 67Ga incorporation into human granulocytes.

Human granulocytes accumulate 67Ga when incubated under anoxic conditions and exclude the isotope when oxygenated. When incorporated, 67Ga is associated with the lysosomal fraction of the granulocytes. The ability of granulocytes to exclude the isotope except under hypoxic conditions may explain 67Ga localization in abscesses and some tumor masses.

Adult↗
PubMed1978

Inhibition of lysozyme by polyvalent metal ions.

The rate of hen egg-white lysozyme (mucopeptide N-acetylmuramoylhydrolase, EC 3.2.1.17), catalysis was determined in the presence of various metal ions (Co2+, Zn2+ and eight of the trivalent lanthanide ions). In the assay system employed, the lanthanides were found to inhibit more strongly than either Zn2+ or Co2+. The inhibition data was fitted to several models of the interactions of the metal ion with the enzyme. These models ranged in complexity from a single inhibitory metal binding site on the enzyme (two-parameter fit) to the presence of two non-independent and non-equivalent inhibitory metal binding sites (five-parameter fit). The more complicated models did not fit the data more precisely than the simplest one-site model, suggesting that the adoption of the simpler model is warranted. The fact that the association constants obtained from the simplest analysis for Co2+ (1.3 +/- 1.9 . 10(2) M-1) and Gd3+ (7.0 +/- 2.6 . 10(3) M-1) are consistent with literature values determined from spectroscopic measurements further supports the validity of the simplest model.

Cobalt↗
PubMed1976

Protein-mediated uptake of vitamin B12 by isolated mitochondria.

Protein-mediated B12 uptake by isolated rat liver mitochondria has been shown to be enhanced by plasma transcobalamin (TC-II) but not by salivary R binder in vitro. The process is enhanced by calcium and depends on active mitochondrial respiration. Following uptake, cyanocobalamin is converted to adenosyl and methylcobalamins and released from the mitochondria. TC-II appears to be required for both cellular and mitochondrial uptake of vitamin B12.

Animals↗
PubMed1975

Antigenic properties of subcellular fractions from canine pancreas: development of a zymogen membrane specific antibody.

Immunization of rabbits with a membrane preparation from dog pancreas produced precipitating antibody against an antigen present in the pancreas of several mammals. This antigen appears to be organ-specific but not species-specific and is localized in the pancreatic zymogen granule membrane fraction. It is thought to represent glycoproteins of mol wt 70,000-90,000 as well as a smaller species of mol wt less than 10,000.

Animals↗