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Biomedical subjects

M R Grever

Publications and source records attributed to M R Grever.

At least 91 records · Page 5Linked to original sources
PubMed1985

Low-dose deoxycoformycin in lymphoid malignancy.

Deoxycoformycin (dCF), a potent inhibitor of adenosine deaminase (ADA), was explored for its antineoplastic potential in 28 patients with advanced lymphoid malignancy. Both normal and malignant B lymphocytes have low levels of ADA activity, and low doses of dCF profoundly inhibit this enzyme in the peripheral blood of patients with chronic lymphocytic leukemia (CLL). The low doses of dCF administered in this trial (4 mg/m2) were not associated with prohibitive toxicity. Five of 28 patients had an objective response. Four additional patients had clinical improvement. No significant difference in the pretreatment ADA activity existed between responding patients and treatment failures. The demonstration of responses to dCF following failure on standard alkylating agents suggests that dCF may not be cross-resistant with current agents used to treat CLL. Additional studies should be pursued using low-dose dCF in patients with advanced malignancy.

Adenosine Deaminase Inhibitors↗
PubMed1984

Phase I trial of teroxirone.

Teroxirone is a novel triepoxide, synthesized as an alkylator and showing a broad spectrum of preclinical activity. It has good cytotoxic activity against sublines of P388 and L1210 leukemias resistant to another alkylating agent, cyclophosphamide. Thirty-six patients received teroxirone as a single iv push for 5 sequential days every 4 weeks. The dose-limiting toxic effects were phlebitis and cutaneous "flare" reactions, with a maximal tolerated dose of 340 mg/m2/day X 5. Nausea, vomiting, and myelosuppression were present but were not dose-limiting at the maximal tolerated dose. This dose would probably be a reasonable dose for phase II trials, but could not be delivered repeatedly without a central line. Since the local reactions were very severe and unique, we believe that studies on the safety of repeated administration via a central line should be completed in animals before trials of systemic therapy in humans begin.

Adolescent↗
PubMed1984

A biological marker model for predicting disease transitions.

For patients with chronic myelogenous leukemia (CML), the effect of elevated blood levels of adenosine deaminase (ADA) is studied as a marker for transitions from stable disease to blast crisis and then to death. Data in the form of snapshots over time, with day, state of disease, and ADA level, are analyzed for 55 patients. A simple three-state Markov model with one-way transition probabilities dependent on ADA is used to determine if the marker has a significant effect on the prediction of changes from stable disease to blast crisis.

Adenosine Deaminase↗
PubMed1983

Differential excretion of modified nucleosides in adult acute leukemia.

Excretion of modified nucleosides in urine was measured in 23 adults with acute leukemia to determine correlation of nucleoside excretion with disease activity. In addition, differences in excretion between patients with acute lymphoblastic leukemia (ALL) and patients with acute myeloid leukemia (AML) were established. Six modified nucleosides were resolved and quantitated by reversed-phase high-performance liquid chromatography (HPLC). Patients with ALL at initial diagnosis or in relapse had significantly higher concentrations of 1-methylinosine and N2,N2-dimethylguanosine in their urine compared to patients in remission (p less than 0.01, p less than 0.05, respectively). One patient with ALL was followed with serial nucleoside determinations over a period of 18 mo; nucleoside excretion correlated closely with disease activity. Nucleoside excretion in patients with AML did not change significantly with disease activity. Considering only those patients at initial diagnosis or in relapse, excretion of 1-methylinosine and N2,N2-dimethylguanosine was significantly higher in ALL than in AML (p less than 0.01, p less than 0.05, respectively). Thus, urinary excretion of 1-methylinosine and N2,N2-dimethylguanosine by adults with acute leukemia may prove to be valuable clinically in following disease activity in patients with ALL and in distinguishing patients with ALL from those with AML.

Adenosine↗
PubMed1983

Adenosine deaminase and terminal deoxynucleotidyl transferase: biochemical markers in the management of chronic myelogenous leukemia.

Serial determinations of adenosine deaminase (ADA) activity in 69 patients with chronic myelogenous leukemia provided a biochemical marker of disease activity. Eighty-nine % of patients in the accelerated phase had an elevation of ADA activity. This elevation was not a direct reflection of an increased absolute blast count. Furthermore, five of seven patients studied serially from the stable phase into the accelerated phase had an increase in ADA activity before the absolute blast count increased. This is the first investigation which clearly demonstrates the potential value of measuring serial ADA activities in a large number of patients with chronic myelogenous leukemia.

Adenosine Deaminase↗
PubMed1983

Urinary excretion of modified nucleosides in chronic myelogenous leukemia.

Urinary excretion of modified nucleosides was measured in 15 patients with Philadelphia chromosome-positive CML to determine the correlation with activity of this disease. Resolution and quantitation of seven nucleosides were accomplished with reversed-phase HPLC. Patients in the stable phase of CML had excretion levels one to two times normal, whereas patients in the blastic phase showed elevations up to 12 times normal. The nucleosides showing the most significant differences in excretion between stable phase and blastic phase were 1-methylinosine, pseudouridine, and N2,N2-dimethylguanosine (p less than 0.01, p less than 0.001, and p less than 0.01, respectively). Nucleoside excretion was also determined in patients with bacterial pneumonia and urinary tract infection for comparison. Serial nucleoside determinations were made in two patients with CML and found to correlate closely with disease activity. The degree of elevation and the correlation with disease activity suggest the potential value of urinary nucleoside quantitation in monitoring patients with CML; in particular, nucleoside excretion may be useful in detecting early blastic transformation.

Adult↗
PubMed1983

Relationship of urinary excretion of modified nucleosides to disease status in childhood acute lymphoblastic leukemia.

The levels of urinary excretion of five modified nucleosides were quantitated by high-performance liquid chromatography for 15 normal children and 24 children with acute lymphoblastic leukemia (ALL). Excretion of each nucleoside decreased linearly with age when quantitation was based on urine creatinine content. Patients with childhood ALL at initial diagnosis or in relapse had significantly higher concentrations of 1-methylinosine, N2,N2-dimethylguanosine, 1-methylguanosine, and pseudouridine in their urine when compared to the concentrations in either patients in remission (P less than 0.001, P less than 0.001, P less than 0.01, and P less than 0.05, respectively) or normal controls (P less than 0.001, P less than 0.02, P less than 0.01, and P less than 0.001, respectively). Excretion of 2-pyridone-5-carboxamide-N'-ribofuranoside did not show significant differences. Urinary excretion of 1-methylinosine demonstrated a positive linear relationship with the percentage of blast cells in the bone marrow [correlation coefficient (r) = 0.90]; the other nucleosides had lower degrees of correlation. In comparison, the absolute blast cell count in the peripheral blood showed less correlation to the percentage of blast cells in the bone marrow (r = 0.47) than did four of the five nucleosides. The data demonstrate that excretion of modified nucleosides reflects disease activity in childhood ALL and that the urinary nucleosides could be useful clinical markers for this disease.

Adolescent↗
PubMed1983

An investigation of 2'-deoxycoformycin in the treatment of cutaneous T-cell lymphoma.

We have investigated the use of 2'-deoxycoformycin (DCF), a potent inhibitor of adenosine deaminase (ADA), in the treatment of 4 patients with advanced mycosis fungoides (MF). Since DCF has demonstrated an adverse effect in vitro and in vivo on the survival of leukemia T-cell lines, it appeared reasonable to examine its effect in patients with advanced cutaneous T-cell lymphoma. A total of 8 courses of DCF were given to the 4 patients. Since this study was part of an ongoing phase I investigation, each patient received a fixed dose (varying from 4 mg/sq m to 10 mg/sq m daily for 3 consecutive days) on a 28-day schedule. One patient had reversible renal insufficiency. Three patients had reversible myelosuppression. Two patients had a complete remission of disease for 7+ and 9+ mo. respectively. Two additional patients had partial remissions for 4 and 9 mo, respectively. We concluded that effective antitumor activity in advanced MF can be achieved with DCF at doses that may not be associated with prohibitive toxicity. We would encourage further investigation of this agent in patients with advanced cutaneous T-cell lymphoma.

Adenosine Deaminase↗
PubMed1982

2'-deoxycoformycin (DCF) and 9-beta-D-arabinofuranosyladenine (Ara-A) in the treatment of refractory acute myelocytic leukemia.

The combination of 2'-deoxycoformycin (DCF), a potent adenosine deaminase (ADA) inhibitor, and 9-beta-D-arabinofuranosyladenine (Ara-A) was used in a patient with acute nonlymphocytic leukemia refractory to all conventional modes of therapy. DCF was given by periodic iv injections to ablate ADA activity. Ara-A was given by continuous iv infusion at an initial dose of 1.5 mg/kg/day, with progressive increases to 6 mg/kg/day. With adequate ADA suppression (less than 2 x 10(-2) mumols of inosine/hr/10(6)h cells), the Ara-A decreased the absolute peripheral blood myeloblast count from 36,332 to 780/microliter. The patient experienced no renal, hepatic, or neurologic complications during therapy.

Adenosine Deaminase↗
PubMed1982

Preliminary studies of continuous extracorporeal carbamylation in the treatment of sickle cell anemia.

The lack of effective therapy of sickle cell anemia has prompted investigation of a large number of antisickling agents. The most promising drug, cyanate, was found in previous studies to be toxic when given systemically. The present study examined a semiautomated system for extracorporeal treatment with cyanate of the blood of four patients with sickle cell anemia. All patients achieved hemoglobin carbamylation levels greater than 1 mode of cyanate per mode of Hb4, with minimal systemic exposure to cyanate and no serious toxicity. Hematologic response occurred in two patients and possibly a third. Further study will be required to determine the efficacy of continuous extracorporeal carbamylation in the treatment of sickle cell anemia.

Adult↗
PubMed1981

The biochemical and clinical consequences of 2'-deoxycoformycin in refractory lymphoproliferative malignancy.

A deficiency of adenosine deaminase, an enzyme important in purine nucleoside catabolism, is associated with a severe combined immunodeficiency disease in children. Inhibition of this enzyme in vitro and in vivo results in an impairment in lymphoblast proliferation. We have investigated the pharmacologic inhibition of this enzyme by 2'-deoxycoformycin in 15 patients with hematologic malignancies. Biochemical consequences of the administration of this agent were closely monitored in erythrocytes, nucleated peripheral blood and bone marrow cells, serum, and urine. A marked rise in erythrocyte dATP was accompanied by a depletion of ATP in those patients exhibiting toxicity. Most patients excreted large amounts of deoxyadenosine but not adenosine in the urine. Serum deoxyadenosine rose in patients demonstrating a marked decrease in cell mass. The biochemical disturbances and clinical toxicity, including hepatic, renal, and conjunctival abnormalities, were usually reversible. Central nervous system toxicity, which potentially was the most serious consequence, was associated with high erythrocyte dATP/ATP ratios and high levels of cerebrospinal fluid deoxyadenosine. In patients with lymphoma and leukemia, objective responses were observed but were short-lived. Patients with chronic lymphocytic leukemia receiving weekly low doses of the drug demonstrated minimal toxicity and some efficacy. The chemotherapeutic potential o 2'-deoxycoformycin, as either a single agent or in combination with Ara-A, merits further exploration.

Adenosine Deaminase↗
PubMedDate not supplied

Carboxyamido-triazole (CAI)--a novel "static" signal transduction inhibitor induces apoptosis in human B-cell chronic lymphocytic leukemia cells.

Signal transduction is a key mechanism by which both proliferative and apoptotic processes of B-cell chronic lymphocytic leukemia (CLL) cells are mediated. Carboxyamido-triazole (CAI) is a cytostatic signal transduction inhibitor currently being tested in phase II clinical trials. Based on this, we investigated the in vitro activity of CAI in mononuclear cell isolates from patients with B-CLL (n=11). Viability, utilizing the MTT assay, was assessed at varying concentrations (0.01-100 microM) of CAI for 4 days. The CAI concentration required for 50% inhibition of cell viability (LC50), determined by the tetrazolium dye (MTT) assay, at 4 days was 53.5 microM (range 29-74.6; 95% CI+/-14.8). Cells from 6 of 11 patients (3 of whom were clinically fludarabine refractory) had a 27 percent (range 11-43) mean decline in viability at 10 microM after a 4 day drug exposure, a concentration readily attainable in humans. To assess if loss of viability was due to apoptosis, we incubated cells from 4 additional CLL patients with media or CAI (10 microM) for 4 days. Annexin-V/propidium iodine labeling subsequently demonstrated CAI significantly (p=0.049) induces apoptosis (40.1%; 95% CI+/-18.1) as compared to media matched control cells (18.3%; 95% CI+/-11.2). These data provide evidence that CAI can induce apoptosis in human CLL cells in vitro at drug concentrations attainable in vivo. These findings justify phase II studies of CAI in patients with B-CLL.

Antineoplastic Agents↗