Discovery and synthesis of tetrahydropyrimidinedione-4-carboxamides as endothelial lipase inhibitors

Endothelial lipase (EL) inhibitors have been shown to elevate HDL-C levels in pre-clinical murine models and have potential benefit in prevention and treatment of cardiovascular diseases. Modification of the 1-ethyl-3-hydroxy-1,5-dihydro-2H-pyrrol-2-one (DHP) lead, 1, led to the discovery of a series of potent tetrahydropyrimidinedione (THP) EL inhibitors. Synthesis and SAR studies including modification of the amide group, together with changes on the pyrimidinone core led to a series of arylcycloalkyl, indanyl, and tetralinyl substituted 5-amino or 5-hydroxypyrimidinedione-4-carboxamides. Several compounds were advanced to PK evaluation. Among them, compound 4a was one of the most potent with measurable EL_HDL hSerum potency and compound 3g demonstrated the best overall pharmacokinetic parameters.     

Pyridazine and pyridazinone derivatives as potent and selective factor XIa inhibitors

Pyridazine and pyridazinone derivatives were designed and synthesized as coagulation factor XIa inhibitors. Potent and selective inhibitors with single digit nanomolar affinity for factor XIa were discovered. Selected inhibitors demonstrated moderate oral bioavailability.     

Critical Periods of Sensitivity of Sexually Dimorphic Spinal Nuclei to Prenatal Testosterone Exposure in Female Rats

Male rats normally have more neurons than do females in two nuclei of the lumbar spinal cord, the spinal nucleus of the bulbocavernosus (SNB) and the dorsolateral nucleus (DLN). Female rats exposed to testosterone propionate (TP) on the 2 days of gestation (Days 18 and 19) when males normally experience a surge in plasma testosterone showed a maximal increase in both SNB and DLN neuronal number. TP exposure just prior to, or following, Days 18 and 19 led to smaller increments. Administration of a small (5 μg) dose of TP after birth, while having no effect by itself, synergized with prenatal TP to enhance the number of SNB neurons. DLN neurons were less responsive to postnatal TP. The somal and nuclear size of SNB, but not DLN, neurons was increased by perinatal TP. Paradoxically, the number of DLN neurons with large somas (1358 μm²or larger) was reduced by perinatal TP, a finding congruent with a previous report that females and feminized males have more of these large DLN neurons than control males. Our data suggest an exquisite sensitivity of the developing spinal nuclei to the timing of hormonal surges normally found in fetal males. Exposure to androgens during a brief prenatal period is needed to assure responsiveness to the low amounts of androgen circulating during neonatal ontogeny, when the process of sexual differentiation is completed.     

Huntington disease: no evidence for locus heterogeneity

A total of 63 families with Huntington disease (HD) were examined for linkage between HD and G8 (D4S10). The families included 57 Caucasian, four Black American, and two Japanese. The combined maximum lod score was 87.69 at theta = 0.04 (99% confidence interval 0.018-0.071). The maximum frequency of recombination was 0.03 in males and 0.05 in females. Fifty-seven families gave positive lod scores; five small families gave mildly negative lod scores. The maximum likelihood estimate of alpha, the proportion of linked loci, was 1.0 with a lower 99% confidence interval of 0.88. These data suggest that there is only one HD locus, although a second rare locus cannot be ruled out.     

Filamentous Proteins from Plant Sieve Tubes

PROTEIN filaments are characteristic structural components of the assimilatory conducting elements of angiosperm plants (“P protein” of Cronshaw and Esau¹). We have isolated filamentous structures from the phloem exudate of cut cucurbit stems². The presence of the filaments could be clearly demonstrated after negative staining with the electron microscope.     

Renal blood flow in normal dogs and in dogs with experimental liver cirrhosis following the acute continuous infusion of endotoxin

The purpose of this study was to determine if the renal circulation of normal and cirrhotic dogs behave similarly in response to an acute endotoxin infusion. Endotoxin was administered as a slow continuous infusion (13-26 micrograms/min) to a total of 20 normal dogs through the femoral vein, portal vein, or into the left renal artery. In each case, there was an initial increment in renal blood flow, of the order of 46%, while arterial blood pressure was actually declining. After 8-20 min, blood flow fell as perfusion pressure declined further. The initial increment in renal perfusion was not due to a hyperthermic response following the endotoxin. When similar doses were given to five dogs with chronic biliary cirrhosis and ascites, the biphasic response in renal perfusion was not observed, rather blood flow declined as perfusion pressure declined. When normal dogs were infused with bilirubin, bile salts, noradrenaline, and angiotensin in pressor doses, the subsequent infusion of endotoxin still produced the usual biphasic response in renal perfusion. Chronic elevation of portal pressure (but not acute elevation), volume contraction by diuresis or hemorrhage, and the infusion of bile intravenously, all abolished the biphasic response in renal perfusion and reproduced in normal dogs the response to endotoxin observed in cirrhotic dogs. Investigation of the factors causing the initial decrease in intrarenal vascular resistance in normal dogs following the endotoxin infusion implicated a role for histamine, kinins, and prostaglandins. We conclude there is a fundamental difference in the response of the renal circulation of normal and cirrhotic dogs to an endotoxin infusion, which may depend on failure of this latter group to release one or more humoral agents. This difference may be due to elevated portal pressure, a decreased effective arterial blood volume, or the products of bile having access to the circulation in cirrhotic dogs.     

Genetic linkage map of human chromosome 21

Two of the most common disorders affecting the human nervous system, Down syndrome and Alzheimer's disease, involve genes residing on human chromosome 21. A genetic linkage map of human chromosome 21 has been constructed using 13 anonymous DNA markers and cDNAs encoding the genes for superoxide dismutase 1 (SOD1) and the precursor of Alzheimer's amyloid beta peptide (APP). Segregation of restriction fragment length polymorphisms (RFLPs) for these genes and DNA markers was traced in a large Venezuelan kindred established as a "reference" pedigree for human linkage analysis. The 15 loci form a single linkage group spanning 81 cM on the long arm of chromosome 21, with a markedly increased frequency of recombination occurring toward the telomere. Consequently, 40% of the genetic length of the long arm corresponds to less than 10% of its cytogenetic length, represented by the terminal half of 21q22.3. Females displayed greater recombination than males throughout the linkage group, with the difference being most striking for markers just below the centromere. Definition of the linkage relationships for these chromosome 21 markers will help refine the map position of the familial Alzheimer's disease gene and facilitate investigation of the role of recombination in nondisjunction associated with Down syndrome.