Gastrointestinal stromal tumor of the pelvic soft tissue presenting with symptomatic hypoglycemia: A case report and brief review of current literature of non-islet cell tumor-induced hypoglycemia.

► Presentation of a rare case of pelvic gastrointestinal stromal tumor. ► Non-islet cell induced hypoglycemia causing severe hypoglycemia. ► The pathogenesis of non-islet cell induced hypoglycemia due to over-production of precursors of insulin-like growth factor-II. ► Complete resolution of hypoglycemia following resection of the tumor.

The significance of a thickened endometrial echo in asymptomatic postmenopausal patients.

OBJECTIVE: The purpose of this study was to evaluate the significance of a thickened endometrial echo in an asymptomatic, postmenopausal patient. STUDY DESIGN: A retrospective review was conducted of all women who underwent transvaginal ultrasonography between January 2003 and August 2008, were found to have an endometrial thickness of at least 5mm and were subjected to endometrial sampling. RESULTS: Sixty-five postmenopausal women, without vaginal bleeding underwent ultrasonographic evaluation with subsequent endometrial sampling. The mean endometrial stripe thickness was 9.7 mm (range: 5.4-22). Four (6.2%) cases of simple/complex hyperplasia were identified and two (3.1%) cases of atypical hyperplasia were diagnosed. Zero (0%) specimens were identified as adenocarcinoma. Twenty-eight (43.1%) polyps and eleven (16.9%) leiomyomata were identified. CONCLUSION: The use of transvaginal sonography as a screening tool in this population is not validated and need not trigger routine evaluation.

Regulation of expression of BIK proapoptotic protein in human breast cancer cells: p53-dependent induction of BIK mRNA by fulvestrant and proteasomal degradation of BIK protein.

Induction of mRNA for BIK proapoptotic protein by doxorubicin or gamma-irradiation requires the DNA-binding transcription factor activity of p53. In MCF7 cells, pure antiestrogen fulvestrant also induces BIK mRNA and apoptosis. Here, we provide evidence that, in contrast to doxorubicin or gamma-irradiation, fulvestrant induction of BIK mRNA is not a direct effect of the transcriptional activity of p53, although p53 is necessary for this induction. It is known that p53 up-regulated modulator of apoptosis (PUMA) mRNA is induced directly by the transcriptional activity of p53. Whereas gamma-irradiation induced both BIK and PUMA mRNA, only BIK mRNA was induced by fulvestrant. Whereas both fulvestrant and doxorubicin induced BIK mRNA, only doxorubicin enhanced the DNA-binding activity of p53 and induced PUMA mRNA. Small interfering RNA (siRNA) suppression of p53 expression as well as overexpression of dominant-negative p53 effectively inhibited the fulvestrant induction of BIK mRNA, protein, and apoptosis. Transcriptional activity of a 2-kb BIK promoter, which contained an incomplete p53-binding sequence, was not affected by fulvestrant when tested by reporter assay. Fulvestrant neither affected the stability of the BIK mRNA transcripts. Interestingly, other human breast cancer cells, such as ZR75-1, constitutively expressed BIK mRNA even without fulvestrant. In these cells, however, BIK protein seemed to be rapidly degraded by proteasome, and siRNA suppression of BIK in ZR75-1 cells inhibited apoptosis induced by MG132 proteasome inhibitor. These results suggest that expression of BIK in human breast cancer cells is regulated at the mRNA level by a mechanism involving a nontranscriptional activity of p53 and by proteasomal degradation of BIK protein.

Importance of dosage standardization for interpreting transcriptomal signature profiles: evidence from studies of xenoestrogens.

To obtain insights into similarities and differences in the biological actions of related drugs or toxic agents, their transcriptomal signature profiles (TSPs) have been examined in a large number of studies. However, many such reports did not provide proper justification for the dosage criteria of each agent. Using a well characterized cell culture model of estrogen-dependent proliferation of MCF7 human breast cancer cells, we demonstrate how different approaches to dosage standardization exert critical influences on TSPs, leading to different and even conflicting conclusions. Using quantitative cellular response (QCR)-based dosage criteria, TSPs were determined by Affymetrix microarray when cells were proliferating at comparable rates in the presence of various estrogens. We observed that TSPs of the xenoestrogens (e.g., genistein or bisphenol A) were clearly different from the TSP of 17beta-estradiol; namely, the former strongly enhanced expression of genes involved in mitochondrial oxidative phosphorylation, whereas the latter showed minimal effects. In contrast, TSPs for genistein and 17beta-estradiol were indistinguishable by using the marker gene expression-based dosage criteria, conditions in which there was comparable expression of the mRNA transcripts for the estrogen-inducible WISP2 gene. Our findings indicate that determination and interpretation of TSPs in pharmacogenomic and toxicogenomic studies that examine the transcriptomal actions of related agents by microarray require a clear rationale for the dosage standardization method to be used. We suggest that future studies involving TSP analyses use quantitative and objective dosage standardization methods, such as those with quantitative cellular response or marker gene expression-based dosage criteria.

Alteration of neuronal firing properties after in vivo experience in a FosGFP transgenic mouse.

Identifying the cells and circuits that underlie perception, behavior, and learning is a central goal of contemporary neuroscience. Although techniques such as lesion analysis, functional magnetic resonance imaging, 2-deoxyglucose studies, and induction of gene expression have been helpful in determining the brain areas responsible for particular functions, these methods are technically limited. Currently, there is no method that allows for the identification and electrophysiological characterization of individual neurons that are associated with a particular function in living tissue. We developed a strain of transgenic mice in which the expression of the green fluorescent protein (GFP) is controlled by the promoter of the activity-dependent gene c-fos. These mice enable an in vivo or ex vivo characterization of the cells and synapses that are activated by particular pharmacological and behavioral manipulations. Cortical and subcortical fosGFP expression could be induced in a regionally restricted manner after specific activation of neuronal ensembles. Using the fosGFP mice to identify discrete cortical areas, we found that neurons in sensory-spared areas rapidly regulate action potential threshold and spike frequency to decrease excitability. This method will enhance our ability to study the way neuronal networks are activated and changed by both experience and pharmacological manipulations. In addition, because activated neurons can be functionally characterized, this tool may enable the development of better pharmaceuticals that directly affect the neurons involved in disease states.