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Biomedical subjects

A Freeman

Publications and source records attributed to A Freeman.

At least 163 records · Page 9Linked to original sources
PubMed1978

The JAVMA today.

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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↗
PubMed1974

Chemically modified nylons as supports for enzyme immobilization. Polyisonitrile-nylon.

Four-component condensations between amine, carboxyl, isocyanide and aldehyde lead to the formation of N-substituted amides (Ugi, 1962). The present paper describes the use of such condensations for the introduction of chemically reactive groups on to the polyamide backbone of nylon. Polyisonitrile-nylon was synthesized by partial hydrolysis of nylon-6 powder, followed by resealing of the newly formed -CO(2)... NH(2) (-) pairs via a four-component condensation, by using acetaldehyde and 1,6-di-isocyanohexane. Polyisonitrile-nylon could also be converted into a diazotizable arylamino derivative, polyaminoaryl-nylon, by a four-component condensation by using a bifunctional amine, pp'-diaminodiphenylmethane, in the presence of an aldehyde and a carboxylate compound. The versatility of four-component condensations involving the isocyanide functional group of polyisonitrile-nylon allowed coupling of proteins, in an aqueous medium at neutral pH, through either their amino or carboxyl groups. Trypsin and papain were bound to polyisonitrile-nylon through their amino groups by a four-component condensation by using acetaldehyde and acetate; conversely, succinyl-(3-carboxypropionyl-)trypsin, pepsin and papain were coupled through their carboxyl groups in the presence of acetaldehyde and an amine (Tris). Diazotized polyaminoaryl-nylon could be utilized for the immobilization of papain, via the tyrosine residues of the enzyme.

Chemical Phenomena↗