An isolated perfused preparation was developed for the study of several aspects of the oculomotor system of the blue crab, Callinectes sapidus. The system for eyestalk rotation was investigated on an extracellular level. Two antagonistic pairs of muscles under visual and statocyst control were found to be responsible for stabilization and rotation of the eyestalk. The primary sensory input to the muscles appears to be from the statocysts, with both static position sense and dynamic acceleration components influencing the motor response. Two sensory feedback systems from mechanoreceptive hairs were found which influence the response of the eye stalks to statocyst input. The function of one system appears to be to allow· the animal to differentiate between statocyst stimulation caused by whole body movement and that caused by movement of the basal segment of the antennule in which the statocyst is lodged. The second negative feedback system appears to have a multiple function. It is believed to function to null out the tonic excitatory position sense input from the statocysts when it is necessary for the eye to make a movement which is contrary to the position sense input as, for example, when the animal is following a visual target whose direction is opposite to that of the statocyst drive. It also produces reciprocal inhibition of the antagonist muscle. In addition, this system may be responsible for the incomplete compensation seen in compensatory eye movements made in response to pitch of the body. A preliminary survey of the oculomotor neurons and interneurons in the cerebral ganglion established the potential of this ganglion for intracellular recording from components of the oculomotor system. Recordings were made from both motorneurons and interneurons. The recording from interneurone of the oculomotor system was particularly good. Eye movements could be elicted in response to visual and tactile stimuli while recording from the ganglion. The preparation appears ·to be an excellent system in which to undertake an extensive analysis of intracellular events in the neuronal network underlying stereotyped eye movements and could lead to an understanding of the neuronal basis for such movements. In the course of the above work on the oculomotor system, same observations were made on the cor frontale which controls the blood pressure to the cerebral system. The cor frontale had been thought to function as a heart regulating blood flow to the cerebral ganglion. It appears from this work that the cor frontale may not function as a heart but rather as a resistive mechanism for regulation of the blood pressure, more like the vertebrate arteriole. Furthermore, the function of this organ may not be to protect the flow to the cerebral ganglion but rather to insure the constancy of the pressure in the peripheral sensory, integrative and oculomotor apparatus of the eyecup.

The phenylhydrazine-induced erythropoietic mouse spleen is used as a model system to demonstrate the relationship between tissue growth and polyamine metabolism. Phenylhydrazine produced significant changes in spleen weights, hematocrits and reticulocyte counts in Swiss-Webster mice. The average spleen weight went up from a control of 155 mg to 875 mg at 96 hours after phenylhydrazine administration, while a 49% reduction in the value of hematocrit was observed at 72 hours. Reticulocyte counts in peripheral blood went from 0.8 to 58% at 168 hours after treatment with phenylhydrazine. Phenylhydrazine at a dose of 40 mg/kg produced significant increases in the levels of putrescine, spermidine and spermine with maxima reached within 72 hours. The levels of N$\sp1$-acetylspermidine reached a maximum of 2.7-fold compared to control at 96 hours. When the dose of phenylhydrazine was increased to 120 mg/kg, peak levels of acetylated polyamines were reached within 96 hours at which time N$\sp1$-acetylspermidine levels rose to 2.9-fold and N$\sp8$-acetylspermidine levels went from not detectable to detectable levels. the levels of putrescine, spermidine and spermine reached maxima at 96 hours of 289, 1248 and 934 nmoles/g, respectively. DL-$\alpha$-difluoromethylornithine hydrochloride monohydrate (DFMO) inhibited the increases in putrescine levels and potentiated the increases in spermine levels induced by phenylhydrazine, while 7-(N-(3-aminopropyl)amino) heptan-2-one.2HCl (APAH) induced significant increases in the levels of N$\sp8$-acetylspermidine. APAH potentiated the increases in spleen weights induced by phenylhydrazine.

The angiogenic and cardioprotective effects of basic fibroblast growth factor (FGF-2) and vascular endothelial growth factor (VEGF) in the ischemic myocardium have been studied, but expression and release of endogenous FGF-2 and VEGF during myocardial ischemia are poorly understood. In addition, nitric oxide synthase isoforms eNOS and iNOS may play a role in myocardial ischemia. The purpose of this study was to investigate the release of FGF-2 and expression of FGF-2, VEGF, eNOS, and iNOS in the normal and ischemic heart. In Phase I, serum FGF-2 levels in patients undergoing treadmill stress test were measured to investigate correlation between serum FGF-2 levels and presence of ischemic heart disease. The study found that serum FGF-2 in ischemia-positive and ischemia-negative patients was not significantly elevated after treadmill stress test, and serum FGF-2 levels did not differ significantly between ischemia-positive and ischemia-negative patients. In Phase II, FGF-2 levels in coronary effluent from isolated perfused rabbit hearts subjected to low-flow ischemia was measured. Results suggest that FGF-2 is released into the coronary effluent of isolated perfused hearts over time and that this release may be elevated in ischemic (50% flow) hearts. Furthermore, the present study indicates that FGF-2 is released immediately after surgical isolation and instrumentation of the isolated heart. A linear model was developed to describe the release of FGF-2 from the isolated heart as a function of the coronary flow rate Q : [special characters omitted]where t = time and Q = 1 and 3.01 for normal and 50% flow rates respectively. In Phase III, effect of acute low-flow ischemia on FGF-2, VEGF, eNOS, and iNOS mRNA expression was measured in isolated perfused hearts using RT/PCR. Preliminary results indicate that FGF-2, VEGF, and iNOS mRNA expression is upregulated and eNOS expression is decreased in ischemic hearts suggesting that these growth factors play a role in short-term response of the myocardium to ischemia. The results of this study suggest that FGF-2, VEGF, and iNOS mRNA expression are increased, eNOS expression is decreased, and FGF-2 is released in response to low-flow ischemia in the isolated perfused heart.

This dissertation presents three separate studies exploring parents’ perceptions and recommendations for communicating with their third, fourth, and fifth grade children about human sexuality. First, a systematic literature review is presented summarizing past qualitative studies completed in the United States focusing on parents with children aged 18 years and under. This review summarizes (1) demographic information of parents from past studies, (2) perceived communication barriers experienced by parents regarding sexuality communication, and (3) perceived communication facilitators experienced by parents regarding sexuality communication. Second, noting the lack of research within a specific population of parents in the United States, a naturalistic study of parents with children in the third, fourth, and fifth grade is presented. Utilizing an emergent design, one-on-one interviews were conducted with 20 parents living in a town in central Texas. By coding collected data, a thematic analysis was used to summarize emergent themes. Themes included techniques parents utilized to have parent-child conversations about sexuality and discussed topics. Although different techniques and topics were raised, parents showed overall inconsistency in experiences or past discussions. Third, using data from the same 20 interviews, themes emerged from parents regarding recommendations. These included the recommendations that a booklet with age appropriate information on sexuality topics be developed for parents and parent workshops or classes covering age appropriate sexuality knowledge as well as techniques to use in parent-child communication be offered. Schools were the recommended source for these resources. Parents also shared feedback on the newly released National Sexuality Education Standards. Comparing past parent-child conversations on sexuality topics to the NSES, certain topics were discussed yet inconsistency was shown. In addition, parents disagreed on specific standards including those pertaining to the functions of reproductive parts, reproduction, and same sex orientation. Implications of this study are that parental resources are needed to help parents communicate with their children about sexuality beginning at a young age. And, for those resources already existing, including workshops, books, and on-line sources, parents need to be made aware of their existence. In addition, future research is needed to explore if younger children are learning from parent-child conversations about sexuality.