A series of thieno[3,4-d]-, thieno[3,2-d]-, and thieno[2,3-d]pyrimidine-2,4-diones with (phenylpiperazinyl)alkyl substitution at N-3 have been synthesized and evaluated for antihypertensive effects in spontaneously hypertensive rats (SHR). These 49 compounds were compared to the vasodilator standards prazosin and the isosteric quinazoline-2,4-dione SGB 1534. Substitution at the 2-, 3-, or 4-position of the phenyl ring was examined, with that at the 2-position more potent than 4-substitution while the isomeric 3-substituted compounds were least potent. Neither alkylation nor acylation at the N-1 position improved the antihypertensive effects as compared to hydrogen. The three thienopyrimidine-2,4-diones (3-5) that contain a [(2-methoxyphenyl)piperazinyl]ethyl moiety at N-3 and hydrogen at N-1 were found to be potent oral antihypertensive agents in the SHR with doses (mg/kg, po) for reducing systolic blood pressure (SBP) by 50 mmHg (ED-50SBP) of 0.21, 0.19, and 1.0, respectively. The compounds 1-5 were further evaluated for alpha blocking potency by measuring the iv doses necessary to antagonize the phenylephrine pressor response by 50% (ED50) in the SHR. The ED50 values (micrograms/kg) are 10.4, 3.3, 1.7, 2.1, and 15.4, respectively. These results clearly show that all three thiophene systems have potent activity as antihypertensive agents and that 3 and 4 are more potent than 1 or 2 as alpha 1-antagonists in vivo.
Endoscopic ultrahigh-resolution optical coherence tomography (OCT) enables collection of minimally invasive cross-sectional images in vivo, which may be used to facilitate rapid development of reliable mouse models of colon disease as well as assess chemopreventive and therapeutic agents. The small physical scale of mouse colon makes light penetration less problematic than in other tissues and high resolution acutely necessary. In our 2-mm diameter endoscopic time domain OCT system, isotropic ultrahigh-resolution is supported by a center wavelength of 800 nm and full-width-at-half-maximum bandwidth of 150 nm (mode-locked titanium:sapphire laser) combined with 1:1 conjugate imaging of a small core fiber. A pair of KZFSN5/SFPL53 doublets provides excellent color correction to support wide bandwidth throughout the imaging depth. A slight deviation from normal beam exit angle suppresses collection of the strong back reflection at the exit window surface. Our system achieves axial resolution of 3.2 microm in air and 4.4-microm lateral spot diameter with 101-dB sensitivity. Microscopic features too small to see in mouse tissue with conventional resolution systems, including colonic crypts, are clearly resolved. Resolution near the cellular level is potentially capable of identifying abnormal crypt formation and dysplastic cellular organization.
KEy WoRDSendoscopic imaging, imaging of tumor progression, gastrointestinal cancer, colorectal adenoma, gastrointestinal intraepithelial neoplasia, animal models for carcinogenesis, azoxymethane treated mouse model of colorectal neoplasm
Research PaperSerial Endoscopy in Azoxymethane Treated Mice Using Ultra-High Resolution Optical Coherence Tomography ABSTRAcT Purpose: Optical coherence tomography (OCT) is a minimally invasive, depth-resolved imaging tool that can be implemented in a small diameter endoscope for imaging mouse models of colorectal cancer (CRC). In this study, we utilized ultrahigh resolution (UHR) OCT to serially image the lower colon of azoxymethane (AOM) treated A/J mouse models of CRC in order to monitor the progression of neoplastic transformations and determine if OCT is capable of identifying early disease.Experimental Design: Thirteen AOM treated A/J and two control A/J mice were surveyed at four timepoints (8, 14, 22 and 26 weeks post AOM treatment) using a 2.0 mm diameter UHR OCT endoscopic system with 3.2 mm axial and 4.4 mm lateral resolution. Histological samples obtained at the final timepoint served as the diagnostic reference. A blinded expert panel of mouse colon pathologists provided diagnoses from the OCT images based on criteria developed from a separate training set of OCT images. Panel results were compared to histological diagnoses assigned by a blinded pathologist.Results: At the final imaging timepoint, 95% of adenomas and 23% of gastrointestinal neoplasias (38% protruding GINs and 9% non-protruding GINs) were correctly diagnosed. The panel identified 68% of disease foci (95% adenoma, 76% protruding GINs and 13% non-protruding GINs). Over the OCT imaging timepoints, disease progression followed a typical succession, with normal or GIN preceding adenoma.Conclusions: Endoscopic UHR OCT enabled accurate diagnosis of adenomas, identification of protruding GIN and non-destructive visualization of CRC progression, providing a tool for cancer research in animal models.
Optical coherence tomography (OCT), laser-induced fluorescence (LIF), and laser-scanning confocal microscopy (LSCM) were used for the task of multimodal study of healthy and adenomatous mouse colon. The results from each modality were compared with histology, which served as the gold standard. The Apc(Min/+) genetic mouse model of colon cancer was compared with wild-type mice. In addition, a special diet was used for the task of studying the origins of a 680 nm autofluorescent signal that was previously observed in colon. The study found close agreement among each of the modalities and with histology. All four modalities were capable of identifying diseased tissue accurately. The OCT and LSCM images provided complementary structural information about the tissue, while the autofluorescence signal measured by LIF and LSCM provided biochemical information. OCT and LIF were performed in vivo and nondestructively, while the LSCM and histology required extraction of the tissue. The magnitude of the 680 nm signal correlates with chlorophyll content in the mouse diet, suggesting that the autofluorescent compound is a dietary metabolite.
Solid-phase organic synthesis, particularly when used in conjunction with combinatorial techniques, is emerging as a revolutionary technology in chemistry. Multi component reaction systems are particularly valued because several elements of diversity can be introduced in a single transformation thereby expanding the diversity of compound libraries. A variety of multi-component reactions have been successfully adapted for solid-phase technology as described in this review.
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