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Biomedical subjects

R J Speer

Publications and source records attributed to R J Speer.

12 recordsLinked to original sources
PubMed1979

Unsymmetrical C-substituted ethylenediamine platinum coordination complexes: synthesis and activity against mouse leukemia L1210.

A series of new unsymmetrical C-substituted ethylenediamines was prepared. The substituents included branched chain alkyl, cycloalkyl, and phenyl groups. Twenty-eight new platinum compounds were prepared from these diamines and were tested for activity against leukemia L1210. The cycloalkyl substituted ethylenediamines produced especially active compounds. The phenyl-substituted analogs were generally low in activity. The activity of the complexes was compared to aqueous solubility, organic solubility, and amphipathic character. There was good indication that antitumor activity increased as aqueous solubility and hydrophilic character of the molecules increased.

Animals↗
PubMed1965

Activated human Hageman factor (XII).

An improved method for the isolation of highly purified active human Hageman factor has been described. An overall recovery of 25% with a purification of 10(6) has been achieved. Certain of the physical and chemical characteristics of XII have been elucidated. Selective chemical modification of functional groups and a variety of enzymatic assays have been employed in an effort to shed light on the mechanism of action of this procoagulant.

Amino Acids↗
PubMedDate not supplied

Coordination complexes of platinum as antitumor agents.

Rosenberg and VanCamp first reported the bacteriostatic and antitumor properties of certain platinum coordination compounds. This pioneering work has led to the synthesis and testing of a large number of related platinum products and the clinical use of cis-dichlorodiammineplatinum (II). This drug has proven very efficacious against a wide variety of mouse tumors when employed as the sole chemotherapeutic agent and has also been combined successfully with other antitumor agents, such as cyclophosphamide and cytosine arabinsoide. Unfortunately, cis-dichlorodiammineplatinum (II) has a low therapeutic index with renal toxicity being the principal limitation of its use. This has prompted the synthesis and testing of many related platinum compounds, of which cis-dichlorobiscyclopentylamine-platinum (II) and the "platinum blues" appear most promising. Experience in the synthesis, purification, and testing of such products will be discussed together with identification of outstanding unsolved problems in this area.

Animals↗
PubMedDate not supplied

Organo-platinum complexes as antitumor agents (review).

Rosenberg et al discovered in the coordination complexes of platinum a new, novel type of potential antitumor agent. Cisplatin [cis-dichlorodiammine platinum (II)4 proved active against a variety of rodent tumors and acted synergistically when combined with other chemotherapeutic agents. Initial clinical tests by Hill et al in 1971, showed cisplatin to be active against malignant lymphoma, Hodgkin's disease, and certain other malignancies. Significant nephrotoxicity, nausea, and vomiting were noted. Since then, cisplatin has been tested alone and in combination chemotherapy and has proven an efficacious anticancer agent in squamous cell carcinoma of head and neck, ovarian carcinoma, disseminated testicular cancer, and others. Its therapeutic value was acknowledged when approved in 1978 by the U.S. FDA for treatment of the latter cancer. The current clinical literature indicates clearly that the full potential of this drug has not yet been realized. Hydration and diuresis have served to mitigate much of the nephrotoxicity, while significant strides toward amelioration of the nausea and vomiting have also been achieved. Literally, thousands of chemically-related congeners have been synthesized, and many have shown marked potency against rodent tumors. Very few, however, have been evaluated clinically, vis-a-vis malonato trans(-)-1,2-diaminocyclohexane platinum(II); this appears a most promising and fertile area of future investigation.

Animals↗