Design and evaluation of achiral, non-atropisomeric 4-(aminomethyl)phthalazin-1(2H)-one derivatives as novel PRMT5/MTA inhibitors

MRTX1719 is an inhibitor of the PRMT5/MTA complex and recently entered clinical trials for the treatment of MTAP-deleted cancers. MRTX1719 is a class 3 atropisomeric compound that requires a chiral synthesis or a chiral separation step in its preparation. Here, we report the SAR and medicinal chemistry design strategy, supported by structural insights from X-ray crystallography, to discover a class 1 atropisomeric compound from the same series that does not require a chiral synthesis or a chiral separation step in its preparation.

Fragment-Based Discovery of MRTX1719, a Synthetic Lethal Inhibitor of the PRMT5•MTA Complex for the Treatment of MTAP-Deleted Cancers

The PRMT5•MTA complex has recently emerged as a new synthetically lethal drug target for the treatment of MTAP-deleted cancers. Here, we report the discovery of development candidate MRTX1719. MRTX1719 is a potent and selective binder to the PRMT5•MTA complex and selectively inhibits PRMT5 activity in MTAP-deleted cells compared to MTAP-wild-type cells. Daily oral administration of MRTX1719 to tumor xenograft-bearing mice demonstrated dose-dependent inhibition of PRMT5-dependent symmetric dimethylarginine protein modification in MTAP-deleted tumors that correlated with antitumor activity. A 4-(aminomethyl)phthalazin-1(2H)-one hit was identified through a fragment-based screen, followed by X-ray crystallography, to confirm binding to the PRMT5•MTA complex. Fragment growth supported by structural insights from X-ray crystallography coupled with optimization of pharmacokinetic properties aided the discovery of development candidate MRTX1719.

A comparative analysis of the ability of five classes of pharmacological agents to augment skin flap survival in various models and species: an attempt to standardize skin flap research

There is a myriad of research in the pharmacological manipulation of skin flap survival. However, skepticism exists as to whether any of these drugs is clinically useful. We evaluated the efficacy of five categories of agents in improving skin flap survival in five different rat flap models. Diltiazem, isoxsuprine hydrochloride, nitroglycerin, prazosin hydrochloride (two doses), and methyldopa were compared in a double-blind, randomized fashion. Their benefits were assessed in a musculocutaneous flap, axial flap, and three types of random flaps. The "best" drug was determined to be nitroglycerin. Its efficacy was verified in a primate model.

Hetastarch: an alternative colloid in burn shock management

Hetastarch is a synthetic polysaccharide colloid that has been used clinically in the management of multiple trauma, hypovolemic shock, and postoperative cardiac patients. Our objective was to determine whether hetastarch is a safe alternative to blood products in burn shock resuscitation. Twenty-six patients received hetastarch during the colloid phase of resuscitation and were compared to matched historical controls who received either albumin or fresh frozen plasma. Clinical and laboratory parameters were measured on admission and for 4 days after the burn. There was no significant difference in hemodynamics, respiratory status, incidence of bleeding, or renal or liver function among the three colloid groups. The advantages of hetastarch include immediate availability, no dependence on human blood donor population, no risk of serum-transmitted diseases, and lower cost. It can be safely recommended for those patients who object to blood products for resuscitation, in those situations where human donors are few, and when cost is a consideration.

The root-nodule bacteria as factors in clover establishment in the red basaltic soils of the Lismore district, NSW. II. Survival and success of inocula in laboratory trials

Plant growth, nature of nodulation, and serological identification of cultures isolated from nodules have been used to determine the success achieved with inocula of clover rhizobia. The Lismore krasnozems offer difficulties in the way of successful seed inoculation. Milk and phosphate supplements with the inoculum do not obviate the difficulty, but heavier rates of inoculation give a reasonable degree of nodulation even with untreated soils. The unfavourable nature of these soils is reflected in their relatively low rhizobial population and the failure of added cells to persist or multiply at a rate comparable with other soils and conditions. Raising pH to c. 7 by the addition of Ca(OH)2 or CaCO3 markedly improves the soil as a medium for survival and multiplication of clover rhizobia. Even a small rise in pH gives appreciable improvement. Strains of root-nodule bacteria differ markedly in their ability to compete with each other for growth and nodule formation on a host. The relative performance of strains can be affected by such factors as the nature of the soil and the presence and nature of the host. Competition for nodulation need not be related in any simple way to competition for growth. Competition by :"native" strains can be an important factor contributing to success or failure with added inoculum.

The root-nodule bacteria as factors in clover establishment in the red basaltic soils of the Lismore district, NSW. III. Field inoculation trials

Field experience with crimson and subterranean clovers grown in the Lismore red soils has confirmed the importance of successful inoculation with an effective strain of a root-nodule bacterium. Strains of rhizobia, applied singly or in a mixture, differed markedly in their ability to form nodules in the red soils. A relatively heavy dose of inoculum (c. 10 times the usual) was desirable. Superphosphate and dolomite were favourable to nodulation but a trace element mixture that included copper sulphate at the rate of 10 lb per acre proved markedly toxic when put in the drill with inoculated seed. Yield was directly related to the proportion of plants effectively nodulated, whether the latter varied because of the nature of the inoculum or because of fertilizer treatment. Results of inoculation at other centres in the district were very satisfactory. Success has also been obtained with the inoculation of Medicago, pea, and vetch.