The Role of Cell Adhesion Molecules in Cyst Breakdown and Follicle Formation in the Mouse Neonatal Ovary

The total number of oocytes that an individual will have available for reproduction is defined at birth. This established oocyte pool is essential to fertility, as a female loses oocytes throughout her life and never makes more. In the mouse, germ cells form in the fetus and migrate to the gonad, where they undergo mitosis and are referred to as oogonia. These cells are in germ line cysts, which are clusters of germ cells connected by intercellular bridges that form by incomplete cytokinesis. Germ cells in the human also develop in clusters with characteristics of cysts. The cells within the cysts soon begin to enter meiosis, and are now referred to as oocytes. Around post natal day (PND) 2, the cysts undergo a process called cyst breakdown, in which the oocytes break apart and become surrounded individually by granulosa cells. The mechanism of cyst breakdown is currently under investigation, as cysts that fail to properly break down often result in multiple oocyte follicles, which develop abnormally. The regulation of cell adhesion molecules (CAMs) likely plays a role in the process of cyst breakdown, and a hamster model has found two specific CAMs expressed in the ovary during egg cell development, E-Cadherin and N-Cadherin. The presence and location of these CAMs, as well as their role in cyst breakdown and follicle formation in the mouse, is being investigated in this study. Three different experimental techniques were used in order to determine the role of E-Cadherin and N-Cadherin in cyst breakdown and follicle development in the mouse. First, immunicytochemistry was used in order to visualize the proteins in the mouse ovary. Then, organ culture experiments were performed in order to block these proteins during PND1-5 to determine their function. Finally, western blots were performed in order to determine protein expression levels of E-Cadherin and N-Cadherin during development. From these experiments, it can be concluded that both E-Cadherin and N-Cadherin are expressed during development from 17.5 days post coitum (dpc) to PND5. E-Cadherin expression is higher in the cytoplasm of oocytes than in the granulosa cells. Starting at PND2, E-Cadherin is also expressed in the cell membrane of the oocytes, and is localized to certain spots within the membrane. The location of N-Cadherin expression within the ovary was unable to be determined from the immunocytochemistry experiments. Overall, N-Cadherin expression is higher in the neonatal ovary than E-Cadherin expression. Also, E-Cadherin expression increases from PND1 to PND3 and N-Cadherin expression increases from 17.5dpc to PND5

Transauricular embolization of the rabbit coronary artery for experimental myocardial infarction: comparison of a minimally invasive closed-chest model with open-chest surgery

<p>Abstract</p> <p>Introduction</p> <p>To date, most animal studies of myocardial ischemia have used open-chest models with direct surgical coronary artery ligation. We aimed to develop a novel, percutaneous, minimally-invasive, closed-chest model of experimental myocardial infarction (EMI) in the New Zealand White rabbit and compare it with the standard open-chest surgical model in order to minimize local and systemic side-effects of major surgery.</p> <p>Methods</p> <p>New Zealand White rabbits were handled in conformity with the "Guide for the Care and Use of Laboratory Animals" and underwent EMI under intravenous anesthesia. Group A underwent EMI with an open-chest method involving surgical tracheostomy, a mini median sternotomy incision and left anterior descending (LAD) coronary artery ligation with a plain suture, whereas Group B underwent EMI with a closed-chest method involving fluoroscopy-guided percutaneous transauricular intra-arterial access, superselective LAD catheterization and distal coronary embolization with a micro-coil. Electrocardiography (ECG), cardiac enzymes and transcatheter left ventricular end-diastolic pressure (LVEDP) measurements were recorded. Surviving animals were euthanized after 4 weeks and the hearts were harvested for Hematoxylin-eosin and Masson-trichrome staining.</p> <p>Results</p> <p>In total, 38 subjects underwent EMI with a surgical (n = 17) or endovascular (n = 21) approach. ST-segment elevation (1.90 ± 0.71 mm) occurred sharply after surgical LAD ligation compared to progressive ST elevation (2.01 ± 0.84 mm;p = 0.68) within 15-20 min after LAD micro-coil embolization. Increase of troponin and other cardiac enzymes, abnormal ischemic Q waves and LVEDP changes were recorded in both groups without any significant differences (p > 0.05). Infarct area was similar in both models (0.86 ± 0.35 cm in the surgical group vs. 0.92 ± 0.54 cm in the percutaneous group;p = 0.68).</p> <p>Conclusion</p> <p>The proposed model of transauricular coronary coil embolization avoids thoracotomy and major surgery and may be an equally reliable and reproducible platform for the experimental study of myocardial ischemia.</p

Design, Synthesis and Biological Properties of Estrogen Receptor Binding Breast Tumor Localizing Agents

316 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1981.Several steroidal estrogens halogenated on the D-ring were synthesized and subjected to preliminary in vitro evaluation for usefulness as estrogen receptor binding radiopharmaceuticals. Two of these compounds, 16(alpha)-bromoestradiol-17(beta) and 11(beta)-methoxy-16(alpha)-bromoestradiol-17(beta) exhibited high binding affinity for the estrogen receptor, and were predicted to exhibit high binding selectivity as well. They were chosen for development into radiopharmaceuticals with the potential to act as breast tumor localizing agents. A mild, regioselective method for high yield radiobromination of enol acetate derivatives of D-ring steroidal ketones involving in situ oxidation of no-carrier-added radiobromide was developed for the synthesis of {('77)Br}-16(alpha)-bromoestrone-3-acetate and the corresponding 11(beta)-methoxy derivative from estrone-3,17-enol diacetate or 11(beta)-methoxy-estrone-3,17-enol diacetate and no-carrier-added {('77)Br}-sodium bromide. Limited kinetic and mechanistic studies indicated that the oxidizing agent was peroxyacetic acid, and the radiobrominating agent was {('77)Br}-hypobromous acid. The gamma-emitting radiobromoketone acetates were reduced to the desired {('77)Br}-16(alpha)-bromoestradiol-17(beta) or the corresponding 11(beta)-methoxy derivative (and their 17(alpha) epimers) with lithium aluminum hydride. Conditions were optimized (-78(DEGREES)C, 10 min) to minimize debromination on the no-carrier-added scale. High pressure liquid chromtography allowed both radiobrominated estradiol derivatives to be isolated at 1000 Ci/mMol specific activity on a routine basis. Subsequent biological experiments showed that they were concentrated selectively in estrogen target tissues of the immature female rat and estrogen receptor containing DMBA induced mammary tumors in mature female rats by a mechanism presumably involving the estrogen receptor. The radiobrominated 11(beta)-methoxy estradiol was more effective in this respect than the corresponding des-methoxy compound, for the immature uterus-to-blood uptake ratio for {('77)Br}-11(beta)-methoxy-16(alpha)-bromoestradiol-17(beta) was 25.7 (+OR-) 5.9 to 1, while the corresponding ratio for {('77)Br}-16(alpha)-bromoestradiol-17(beta) was 13.0 (+OR-) 3.4 to 1 at one hour post-injection. Other biological experiments concerning the time course of tracer uptake and clearance form the target tissues, subcellular distribution of tracer in target tissues, metabolic fate, and comparison to analogous radioiodinated compounds in vivo as well as experiments concerning the receptor and non-receptor binding properties of the compounds in vitro are described. Both radiobromosteroids were shown to meet all the necessary criteria for use as estrogen receptor binding radiopharmaceuticals. They were used to image DMBA induced mammary adenocarcinoma in mature female rats with the use of the Anger scintillation camera. {('77)Br}-16(alpha)-Bromoestradiol-17(beta) was further evaluated (dosimetry, pharmacology) for use as a scintigraphic agent in humans. This compound was used to obtain an image of a primary human breast tumor that was shown to contain high levels of estrogen receptor upon removal. These results are the first example of scintigraphic imaging of estrogen receptor containing mammary tumors in animals or humans utilizing a receptor binding radiopharmaceutical.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD