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Biomedical subjects

D P Rotella

Publications and source records attributed to D P Rotella.

At least 19 recordsLinked to original sources
PubMed2000

Optimization of substituted N-3-benzylimidazoquinazolinone sulfonamides as potent and selective PDE5 inhibitors.

A previous report from these laboratories identified the N-3-benzylimidazoquinazolinone nucleus as a more selective PDE5 inhibitor template compared to the pyrazolopyrimidine of sildenafil. This paper describes in detail the structure-activity relationships of a set of sulfonamide analogues, several of which are both more potent and more selective PDE5 inhibitors in vitro than sildenafil. The synthesis, in vitro enzyme activity and selectivity, and in vitro functional and preclinical pharmacokinetic assessment of molecules in this series are described.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed2000

N-3-substituted imidazoquinazolinones: potent and selective PDE5 inhibitors as potential agents for treatment of erectile dysfunction.

Phosphodiesterase type 5 (PDE5) inhibitors with improved PDE isozyme selectivity relative to sildenafil may result in agents for the treatment of male erectile dysfunction (MED) with a lower incidence of PDE-associated adverse effects. This paper describes the discovery of 14, a PDE5 inhibitor with improved potency and selectivity in vitro compared to sildenafil. This compound shows activity in a functional assay of erectile function comparable to that of sildenafil.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1999

Rank-order of potencies for inhibition of the secretion of abeta40 and abeta42 suggests that both are generated by a single gamma-secretase.

The Alzheimer's disease amyloid peptide Abeta has a heterogeneous COOH terminus, as variants 40 and 42 residues long are found in neuritic plaques and are secreted constitutively by cultured cells. The proteolytic activity that liberates the Abeta COOH terminus from the beta-amyloid precursor protein is called gamma-secretase. It could be one protease with dual specificity or two distinct enzymes. By using enzyme-linked immunosorbent assays selective for Abeta40 or Abeta42, we have measured Abeta secretion by a HeLa cell line, and we have examined the dose responses for a panel of five structurally diverse gamma-secretase inhibitors. The inhibitors lowered Abeta and p3 secretion and increased levels of the COOH-terminal 99-residue beta-amyloid precursor protein derivative that is the precursor for Abeta but did not alter secretion of beta-amyloid precursor protein derivatives generated by other secretases, indicating that the inhibitors blocked the gamma-secretase processing step. The dose-dependent inhibition of Abeta42 was unusual, as the compounds elevated Abeta42 secretion at sub-inhibitory doses and then inhibited secretion at higher doses. A compound was identified that elevated Abeta42 secretion at a low concentration without inhibiting Abeta42 or Abeta40 at high concentrations, demonstrating that these phenomena are separable pharmacologically. Using either of two methods, IC50 values for inhibition of Abeta42 and Abeta40 were found to have the same rank-order and fall on a trend line with near-unit slope. These results favor the hypothesis that Abeta variants ending at residue 40 or 42 are generated by a single gamma-secretase.

Amyloid Precursor Protein Secretases↗
PubMed1997

Neurotrophic 3,9-bis[(alkylthio)methyl]-and-bis(alkoxymethyl)-K-252a derivatives.

A series of 3,9 disubstituted [(alkylthio)methyl]- and (alkoxymethyl)-K-252a derivatives was synthesized with the aim of enhancing and separating the neurotrophic properties from the undesirable NGF (trk A kinase) and PKC inhibitory activities of K-252a. Data from this series reveal that substitution in the 3- and 9-positions of K-252a with these groups reduces trk A kinase inhibitory properties approximately 100- to > 500-fold while maintaining or in certain cases enhancing the neurotrophic activity. From this research, 3,9-bis[(ethylthio)methyl]-K-252a (8) was identified as a potent and selective neurotrophic agent in vitro as measured by enhancement of choline acetyltransferase activity in embryonic rat spinal cord and basal forebrain cultures. Compound 8 was found to have weak kinase inhibitory activity for trk A, protein kinase C1 protein kinase A, and myosin light chain kinase. On the basis of the in vitro profile, 8 was evaluated in in vivo models suggestive of neurological diseases. Compound 8 was active in preventing degeneration of cholinergic neurons of the nucleus basalis magnocellularis (NBM) and reduced developmentally programmed cell death (PCD) of female rat spinal nucleus of the bulbocavernosus motoneurons and embryonic chick lumbar motoneurons.

Animals↗
PubMed1995

Microbial metabolites of ophiobolin A and antimicrobial evaluation of ophiobolins.

Ophiobolin A [1], 3-anhydroophiobolin A [2], ophiobolin B [3], and ophiobolin L [4] were isolated from fermentation broths of Cochliobolus heterostrophus. Preliminary screening showed that a number of organisms were capable of metabolizing the sesterterpene ophiobolin A [1]. Large-scale transformations of ophiobolin A [1] with Polyangium cellulosum produced 6 and 7 while Pseudomonas aeruginosa produced 8. Resting-cell preparations of Penicillium patulum afforded 9 and 10. The structures of these metabolites were established by spectroscopic methods and by comparison of the spectral data with those of the starting material. The antimicrobial activity of the ophiobolins was also evaluated.

Anti-Bacterial Agents↗
PubMed1989

Synthesis and P-388 antitumor properties of the four diastereomeric 1-hydroxy-3,4-diaminocyclohexane-Cl2PtII complexes.

Synthesis and antileukemic activity in vivo of the four diastereomeric 1-hydroxy-3,4-diaminocyclohexane-Cl2PtII complexes (Cl2PtII-3a-d) are described. Respective bis(phenylmethyl) (1 alpha,2 alpha,4 beta)-, (1 alpha,2 alpha,4 alpha)-, (1 alpha,2 beta,4 beta)-, and (1 alpha,2 beta,4 alpha)-(4-hydroxy-1,2-cyclohexanediyl)bis(carbamates) (5a, 5b, 7a, 7b) were prepared by hydroboration-oxidation of the bis(carbobenzoxyamino) derivatives (4,5) of cis- and trans-4,5-diaminocyclohexene. The relative stereochemistry of intermediates 5a and 5b was established by correlation with the alcohol obtained by NaBH4 reduction of bis(phenylmethyl) (1 alpha,2 alpha,3 alpha,4 alpha)-(3,4-epoxy-1,2-cyclohexanediyl)bis(carbamate) (8), the all-cis stereochemistry of which was unambiguously determined by X-ray crystallographic analysis. In the P-388 murine leukemia model these monohydroxycyclohexanediamine-PtII complexes were more effective than the PtII complexes of the related diol diamines 1a-e but were less active than the cisplatin positive control.

Animals↗