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Magnetic resonance image (MRI) guidance is often necessary for accurate targeting for stereotactic intracranial surgery in animals used for experimental research studies. The magnetic field created by the MR imaging equipment, logistics of the use of stereotactic head frame in confined space and the need to limit movement of the subject during the imaging creates unique challenges. We demonstrate in this study the usefulness of intravenous propofol to anesthetize adult Rhesus monkeys to obtain high resolution 3D MR images immediately followed by conversion to inhalation anesthesia and stereotactic intracranial surgery with the head frame 'in situ.' There was minimal morbidity with achieving a high degree of precision for the stereotactic targeting.

Despite recent advances in diagnosis and treatment of testicular cancer, its causes remain unknown. The most common conditions known to be associated with testicular cancer are cryptorchidism, infertility, and overexposure to pesticides or radiation. Recent studies also indicate hormones may play a crucial role in testicular tumorigenesis. Our studies show that about half of the male transgenic mice overexpressing aromatase in testis were infertile and/or had larger than normal testicles. Gross pathology and histological analysis showed the mice to have Leydig cell tumors, unilaterally or bilaterally. Serum estradiol levels for transgenic mice were at least twice as high as those for nontransgenic mice. Expression of aromatase and estrogen receptor were also very high in testicular tissue of transgenic mice compared to nontransgenic mice. Consistent with increased estrogenic activity in the testicular tissue, we also saw an increase in the levels of genes involved in cell cycle that are regulated by the estrogen. To obtain a better understanding of the biological significance of testicular tumorigenesis, a reliable animal model is necessary to clarify the mechanisms and correlations associated with human cancers. Here we describe such a model, which shows that overexpression of aromatase results in increased estrogen production and a changed hormone milieu, leading to the induction of testicular cancer (Leydig cell tumors). This predictable and useful model is a potential tool for the study of testicular tumorigenesis, hormonal carcinogenesis, synergistic action of other carcinogens on hormone-induced tumors, and tumor dependency on endocrine factors.

The primary objective of this study was to compare the effect of 2 commonly used anesthetics, isoflurane and CO2, on the physiologic stress hormone, corticosterone, in rats during serial blood collections. Circulating corticosterone concentrations were monitored during serial jugular blood sampling in rats exposed to either isoflurane or CO2 anesthesia. Blood was drawn under anesthesia at 6 time points (initial sampling and 0.5, 1, 2, 3, and 24 h after initial sampling) across a 24-h period. The results indicated that corticosterone levels in both anesthesia groups showed a similar pattern of stimulation, indicated by a sharp increase in circulating concentrations by the 0.5-h time point, with further elevation at 1 h, and a decline at subsequent time points. Isoflurane-treated animals showed higher baseline levels of corticosterone at the initial sampling. However, the increase in corticosterone at subsequent time points was significantly higher for animals exposed to CO2, suggesting that the cumulative effects of repeated exposure to stressful stimuli was more evident for this type of anesthesia. The apparent reduction in stress effects of isoflurane as opposed to CO2, coupled with other published adverse effects of CO2, suggests that isoflurane is the better choice when anesthesia is needed for serial blood collection. However, availability of equipment for delivery of anesthetic, scavenging of waste gasses, familiarity of personnel with the anesthetic, and the potential effect of the anesthetic on research endpoints should all be considered in choosing between the 2 anesthetics.

To test directly the role of breast-tissue estrogen in initiation of breast cancer, we have developed the aromatase-transgenic mouse model and demonstrated for the first time that increased mammary estrogens resulting from the overexpression of aromatase in mammary glands lead to the induction of various preneoplastic and neoplastic changes that are similar to early breast cancer. Continued overexpression of aromatase that leads to increased breast-tissue estrogen contributes to a number of epigenetic changes in mammary tissue such as alteration in the regulation of genes involved in apoptosis, activation of genes involved in cell cycle and cell proliferation, and activation of a number of growth factors. Our current studies show aromatase overexpression is sufficient to induce and maintain early preneoplastic and neoplastic changes in female mice without circulating ovarian estrogen. Preneoplastic and neoplastic changes induced in mammary glands as a result of aromatase overexpression can be completely abrogated with the administration of the aromatase inhibitor, letrozole. Consistent with complete reduction in hyperplasia, we have also seen downregulation of estrogen receptor and a decrease in cell proliferation markers, suggesting aromatase-induced hyperplasia can be treated with aromatase inhibitors. Our studies demonstrate that aromatase overexpression alone, without circulating estrogen, is responsible for the induction of breast hyperplasia and these changes can be abrogated using aromatase inhibitors.

A range-image sensor for controlling an agricultural spraying system and the military range- image technology upon which the sensor is based are discussed. Initial testing in an orange grove in Orlando, Florida indicates that sensor control optimizes the chemical spraying process and reduces environmental pollution.