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Biomedical subjects

A Freeman

Publications and source records attributed to A Freeman.

At least 145 records · Page 8Linked to original sources
PubMed1979

Isonitrile derivatives of polysaccharides as supports for the covalent fixation of proteins and other ligands.

A method for the introduction of side chains containing isonitrile (isocyanide, functional group) on the backbone of polysaccharides and other hydroxylic polymers was developed. The method was based on (a) ionization of some of the hydroxyl groups on the polymer by treatment with a strong base (tert-butoxide) in a polar aprotic solvent (dimethylsulfoxide), and (b) introduction of side chains containing isonitrile groups by nucleophilic attack of the polymeric alkoxide ions on a low molecular weight isonitrile containing a good leaving group in the omega-position, (1-tosyl-3-isocyanopropane). By this method, the side chains containing the-NC functional groups are attached to the polymeric backbone via stable ether bonds. The isonitrile derivatives of cellulose, linear and cross-linked dextran and cross-linked agarose utilized for the covalent fixation of high and low molecular weight ligands by four-component reactions carried out in aqueous medium, at neutral pH.

Cellulose↗
PubMed1979

Hypercalcemia complicating childhood malignancies: a report of seven cases with some pathophysiological considerations.

A group of seven children with different malignant processes presenting with hypercalcemia was studied. Bone destruction, diffuse metabolic abnormalities, abnormal acid-base homeostasis and recurrent hypercalcemia characterized these patients. A different mechanism leading to the production of hypercalcemia and/or bone destruction by cancer cells is considered. The results of this report suggest that parathyroid hormone production (P.T.H.) by the parathyroid glands is normal and that ectopic secretion of PTH or PTH-like material is negligible in these cases.

Acid-Base Imbalance↗
PubMed1979

Multilayer immobilized-enzyme filter reactors: urease bound to nylon fabric filters.

Urease was bound to commercially available nonwoven nylon fabric filters. Multilayer immobilized-enzyme filter reactors were constructed by packing varying numbers of urease-nylon filters in a column. Owing to the relatively open structure and high mechanical strength of the filter fabric, compaction and pressure drop effects were minimal. The reactors could be operated in a wide range of substrate concentrations and flow rates under conditions where mass-transfer limitations could be neglected. The kinetic behavior of the immobilized-enzyme filter reactors could be described by a linear form of the integrated Michaelis-Menten equation using a model based on the sequential action of the enzyme filters.

Acrylamides↗
PubMed1979

Remission induction in acute nonlymphocytic leukemia: comparison of a seven-day and ten-day infusion of cytosine arabinoside in combination with adriamycin.

Forty-six previously untreated patients with acute nonlymphocytic leukemia were treated with a remission induction regimen consisting of three daily doses of Adriamycin (30 mg/m2/day) and a ten-day continuous infusion of cytosine arabinoside (ara C) (100 mg/m2/day). The overall remission rate was 72%, with 88% of the patients less than 50 and 62% of patients greater than 50 years old achieving complete remission status. Thirty-one of the 33 complete remissions occurred after a single course of chemotherapy. Retrospective comparison of this regimen with its predecessor (identical, except that a seven-day infusion of ara C was administered) demonstrated that the increase in duration of ara C administration resulted in greater antileukemic effectiveness without an increase in hematologic toxicity to the patient.

Adolescent↗
PubMed1979

Cell-mediated immunity to varicella-zoster virus infection in subjects with lymphoma or leukemia.

Normal subjects and patients with lymphoma or leukemia were tested for the levels of lymphocytes, E-rosette--forming T-cells, serum and vesicle fluid interferon, and specific in vitro proliferative response to varicella-zoster antigen after clinical varicella or herpes zoster illness. The effect of polyinosinic acid/polycytidilic acid on the immune response was also evaluated. The development of VZ specific cell-mediated response in normal subjects was characterized by intense proliferative activity eight to ten days after the onset of illness, with significant decline 70 to 80 days later. The responses in subjects with lymphoma or leukemia were much lower. Few subjects with chickenpox or zoster with lymphoma or leukemia died during the infection. Death was associated with significant depletion of E-rosette--forming T-cells, and grossly deficient specific cellular response to VZ antigen. Treatment with Poly IC frequently induced elevations in serum as well as vesicle fluid interferon levels, and increased the proliferative activity of lymphocytes against VZ antigen.

Adolescent↗
PubMed1979

Treatment of acute nonlymphocytic leukemia: use of anthracycline-cytosine arabinoside induction therapy and comparison of two maintenance regimens.

Patients with acute nonlymphocytic leukemia were given remission induction therapy consisting of cytosine arabinoside and an anthracycline. Those patients who experienced complete remission received two courses of consolidation therapy and were randomized to receive maintenance therapy consisting of either daily chemotherapy with reinforcements every 3 mo or reinforcement therapy only every 6 wk. The overall complete remission rate was 66%, with 80% complete remission for previously untreated patients less than 60 yr of age who did not have a prior history of malignancy. Remission durations were the same for patients treated with both maintenance regimens. The major determinant for successful remission induction therapy was patient age, with older patients frequently succumbing to intercurrent infection. Documented leukemic cell resistance to the therapy employed was only rarely encountered. Once remission was achieved, age was no longer a determinant of patient survival, since duration of remission was independent of age. Remission durations were directly related to leukemic cell retention of cytosine arabinoside triphosphate. Hence therapy for acute nonlymphocytic leukemia can be divided into two separate areas: remission induction and remission maintenance.

Adolescent↗
PubMed1978

High terminal deoxynucleotidyl transferase activity in pediatric patients with acute lymphocytic and acute myelocytic leukemias.

Specificity of TdT5 as a marker for ALL was evaluated by determining its activity in cells from normal control subjects and from 35 pediatric patients with ALL, AML, Hodgkin's disease and disseminated Burkitt's lymphoma. We evaluated the DNA polymerase activity, cell surface phenotypes (E rosettes, EAC rosettes, Smlg and la-like, HTLA and cALL antigens), and hematological and cytochemical characteristics in both the normal and patient groups. DNA polymerase alpha + beta and DNA polymerase gamma activity were indiscriminately high in all immature cells as found in ALL, AML, Burkitt's lymphoma and phytohemagglutinin-stimulated normal lymphocytes, when compared to mature leukocytes found in normal individuals or in patients whose cancer was in remission. High TdT activity was found in 24 of 26 T and non-T/non-B ALL patients in active phase as well as in two of three AML patients one of whom had Auer rods. Thus, TdT, although valuable for monitoring ALL patients, may have limitations in separating AML from ALL.

Adolescent↗
PubMed1978

The JAVMA today.

Explore the source record for details and available documents.

Periodicals as Topic↗
PubMed1978

Vincristine, prednisone and L-asparaginase in the induction of remission in children with acute lymphoblastic leukemia following relapse.

Two hundred and twenty-seven children with recurrent acute lymphoblastic leukemia were treated with various combinations of vincristine, prednisone, cyclophosphamide and L-asparaginase in an approach to the induction of remission. The combination of L-asparaginase 1,000 mu/kg iv q.d. x 10, vincristine 2.0 mg/m2iv q.w. x 4 and prednisone 40 mg/m2 p.o.q.d. x 28 days was found to be highly effective. The incidence of remission was 73%. No significant improvement was achieved when cyclophosphamide was added to this regimen. Various combinations of cytosine arabinoside, cyclophosphamide, vincristine, prednisone, BCNU or CCNU failed to maintain remission duration for more than two or three months. Neither BCNU nor CCNU prevented the development of CNS leukemia.

Adolescent↗
PubMed1976

Granulocyte transfusions in children using filter-collected cells.

Twenty-three children with various stages and morphologic types of leukemia were treated with multiple granulocyte transfusions obtained by filtration leukapheresis when neutropenia-associated infection appeared unresponsive to antibiotics. All children meeting the above qualifications were given granulocyte transfusions during this time period. Twenty-one of 23 became afebrile during or shortly after the transfusions; one died with disseminated Herpes simplex; and one became well enough to be discharged, although he was never free of fever. Frequent mild to moderate fever and chills were noted. One child developed a severe pulmonary reaction followed by resolution of pneumonia. Filtration leukapheresis is a useful adjunct in controlling severe infections in neutropenic children.

Adolescent↗
PubMed1976

Electrophysiological observations on the digitalis-potassium interaction in canine Purkinje fibers.

We studied the effects of elevating potassium concentration on the membrane potential of Purkinje cells exposed to toxic concentrations of acetylstrophanthidin or ouabain. Conventional intracellular microelectrode techniques were employed. Rapid elevation of [K+]o from 2.7 to 5.4 mEq/liter resulted in an initial increase (more negative) in membrane potential of cells demonstrating ouabain-induced phase 4 depolarization. The increase in maximal diastolic potential occurred initially without suppression of phase 4 depolarization. In cells rendered inexcitable by ouabain or acetylstrophanthidin, elevation of [K+]o consistently increased membrane potential and restored excitability. In four experiments automaticity was initiated within 2 minutes after the increase in [K]o. Although automaticity reappeared, as maximal diastolic potential increased, the automatic rate slowed and then pacemaker activity was suppressed. Studies with 3H-ouabain showed that the increase in membrane potential paralleled K+-induced release of 3H-ouabain from Purkinje cells. These studies suggest that elevation of [K+]o reverses digitalis toxic manifestations in canine Purkinje fibers by causing release of cardiac glycosides bound to the membrane. The observed increase in membrane potential of ouabain-treated Purkinje fibers that occurred after [K+]o elevation was considered to be mediated in part by restoration of the Na pump and by electrogenic pumping.

Action Potentials↗