Thesis (Ph. D.)--University of Wisconsin--Madison, 1985. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 135-137).

Beacon is a 73-amino acid peptide encoded by a novel gene in the hypothalamus of Israeli sand rat Psammomys obesus. Reverse transcriptase polymerase chain reaction (RT-PCR) and immunohistochemical techniques were used to investigate the presence of beacon mRNA and the distribution of beacon-immunoreactivity (irBC) in the hypothalamus of ICR mice. RT-PCR experiments revealed beacon mRNA in the mouse hypothalamus. Using a rabbit polyclonal antiserum directed against the synthetic C-terminal peptide fragment (47-73), irBC was detected in the mouse hypothalamus and pituitary. In the hypothalamus, irBC was concentrated in perikarya of the supraoptic (SO), paraventricular (PVH) and accessory neurosecretory nuclei and in cell processes of the median eminence and pituitary stalk. In the pituitary, irBC was noted mainly in the posterior lobe. Double-labeling the hypothalamic sections with guinea-pig vasopressin-antiserum or mouse monoclonal oxytocin-antibody and beacon-antiserum revealed that <30% of vasopressin-immunoreactive neurons and nearly all oxytocin-immunoreactive neurons in the PVH and SO were irBC. The result shows the presence of beacon mRNA in the mouse hypothalamus, and the distribution of irBC is distinctively different from that reported in the hypothalamus of Psammomys obesus, but similar to that of the Sprague-Dawley rats described in our earlier study. More interestingly, Blast search uncovered a 73-amino acid peptide, human ubiquitin-like 5, which has the same exact sequence as beacon. Thus, irBC observed in the mouse brain could be that of ubiquitin-like 5.

With the use of an antiserum against human apelin-36, apelin-immunoreactivity (irAP) was detected in neurons and cell processes of the supraoptic nucleus (SO), paraventricular nucleus (PVH), accessory neurosecretory nuclei (Acc) and suprachiasmatic nucleus. Strongly labeled cells/processes were noted in the internal layer of the median eminence, infundibular stem, anterior and posterior pituitary. Double-labeling the sections with goat polyclonal neurophysin I-antiserum and rabbit polyclonal apelin-antiserum revealed a population of magnocellular neurons in the PVH, SO and Acc expressing both irAP and neurophysin I-immunoreactivity (irNP), the latter being a marker of oxytocin-containing neurons. By inference, the AP-positive but irNP-negative magnocellular neurons could be vasopressin-containing. The presence of irAP in certain hypothalamic nuclei and pituitary suggests that the peptide may be a signaling molecule released from the hypothalamic-hypophysial axis.

published_or_final_version / Physiology / Doctoral / Doctor of Philosophy

No description available.

No description available.

No description available.

No description available.

No description available.

<div>Cancers have the ability to develop resistance to traditional therapies. The important role of the tumor microenvironment in transforming nonaggressive tumor cells into an aggressive and chemoresistant cancer has been abundantly addressed. Mechanical cues from the tumor environment, such as matrix stiffness and geometry, transfer to the cell nucleus via the cytoskeleton and change nuclear morphology (e. g, chromatin organization, size and shape). Such alterations are known to accompany or follow the acquisition of chemoresistance. Nuclear matrix proteins such as the Nuclear Mitotic Apparatus (NuMA) are highly involved in higher order chromatin organization and contribute to sustain the physical structure of the cell nucleus, but it is</div><div>yet to be determined how such structural proteins respond to microenvironmental changes. We have shown previously that tumors cultured in curved geometry (similar to the ductal architecture of breast tissue) display significantly different drug sensitivities compared to those cultured on a flat surface, and that a major morphological difference between these two culture conditions is nuclear shape (i.e., circularity). Our hypothesis is that mechanical cues from the tumor microenvironment alter nuclear features that control the phenotypic response of cancer cells to antiproliferative drugs. Morphological analysis of the cell nucleus in the curved conformation as well as hydrogel and hanging drop systems (with amorphous geometry) showed that only nodules in the curved set-up have nuclear morphometry (shape and size) similar to that of breast tumors of the corresponding subtypes in vivo. In addition, we compared the sensitivity of triple negative breast tumors to cisplatin, with proven efficacy in the clinics, and SAHA, an epigenetic drug that so far failed in breast cancer treatment. Our results suggest higher sensitivity to cisplatin and lower sensitivity to SAHA of breast cancer cells cultured in duct-like geometry compared to the amorphous systems. To evaluate the importance of nuclear morphometry in drug response we altered nuclear size and shape using latrunculin. Under this condition, the number of apoptotic and growth-arrested cells increased following treatments with cisplatin and SAHA, respectively.</div>