165 research outputs found
Inhibitors of oestrogen biosynthesis: preclinical studies with CGS 16949A, a new nonsteroidal aromatase inhibitor
Inhibitors of the aromatase enzyme represent a class of therapeutic agents which potently inhibit oestrogen biosynthesis in vivo. This inhibition of oestrogen biosynthesis is well established as effective therapy in the treatment of oestrogen-dependent breast cancer. CGS 16949A [4-(5,6,7,8-tetrahydroimidazo-[l,5-a]pyridin-5-yl)-benzonitrile hydrochloride] is a non-steroidal imidazole derivative which is a potent competitive aromatase inhibitor in vitro. At a maximally effective concentration, it selectively inhibits aromatase and does not affect glucocorticoid production from the adrenal in vitro. In vivo in the rat, CGS 16949A effectively reduces ovarian oestrogen content and potently inhibits an aromatase-mediated androgen-induced uterine hypertrophy. Oral treatment of adult, cyclic female rats with CGS 16949A disrupts cyclicity, inhibits ovulation, reduces uterine weight and suppresses serum oestradiol, all expected sequelae of oestrogen deprivation. At maximally effective doses, there is no evidence of adrenal hypertrophy, indicating that adrenal steroidogenesis is unaffected. In the DMBA-induced mammary carcinoma model in the rat, CGS 16949A caused almost complete regression of palpable tumours and significantly suppressed the appearance of new tumours at a maximally effective oral dose. Thus, CGS 16949A is a potent and selective inhibitor of the aromatase enzyme. In the rat, it is very efficacious in inhibiting oestrogen biosynthesis and in suppressing the growth of DMBA-induced mammary tumour
Knowledge-based patient screening for rare and emerging infectious/parasitic diseases: a case study of brucellosis and murine typhus.
Many infectious and parasitic diseases, especially those newly emerging or reemerging, present a difficult diagnostic challenge because of their obscurity and low incidence. Important clues that could lead to an initial diagnosis are often overlooked, misinterpreted, not linked to a disease, or disregarded. We constructed a computer-based decision support system containing 223 infectious and parasitic diseases and used it to conduct a historical intervention study based on field investigation records of 200 cases of human brucellosis and 96 cases of murine typhus that occurred in Texas from 1980 through 1989. Knowledge-based screening showed that the average number of days from the initial patient visit to the time of correct diagnosis was significantly reduced (brucellosis-from 17.9 to 4.5 days, p = 0.0001, murine typhus-from 11.5 to 8.6 days, p = 0.001). This study demonstrates the potential value of knowledge-based patient screening for rare infectious and parasitic diseases
Efficacy of the EGFr inhibitor Iressa on development of chemically-induced urinary bladder cancers: Dose dependency and modulation of biomarkers
Exploring causes of interannual variability in the seasonal cycles of tropospheric nitrous oxide
Seasonal cycles in the mixing ratios of tropospheric nitrous oxide (N[subscript 2]O) are derived by detrending long-term measurements made at sites across four global surface monitoring networks. The detrended monthly data display large interannual variability, which at some sites challenges the concept of a "mean" seasonal cycle. In the Northern Hemisphere, correlations between polar winter lower stratospheric temperature and detrended N[subscript 2]O data, around the month of the seasonal minimum, provide empirical evidence for a stratospheric influence, which varies in strength from year to year and can explain much of the interannual variability in the surface seasonal cycle. Even at sites where a strong, competing, regional N[subscript 2]O source exists, such as from coastal upwelling at Trinidad Head, California, the stratospheric influence must be understood to interpret the biogeochemical signal in monthly mean data. In the Southern Hemisphere, detrended surface N[subscript 2]O monthly means are correlated with polar spring lower stratospheric temperature in months preceding the N[subscript 2]O minimum, providing empirical evidence for a coherent stratospheric influence in that hemisphere as well, in contrast to some recent atmospheric chemical transport model (ACTM) results. Correlations between the phasing of the surface N[subscript 2]O seasonal cycle in both hemispheres and both polar lower stratospheric temperature and polar vortex break-up date provide additional support for a stratospheric influence. The correlations discussed above are generally more evident in high-frequency in situ data than in data from weekly flask samples. Furthermore, the interannual variability in the N[subscript 2]O seasonal cycle is not always correlated among in situ and flask networks that share common sites, nor do the mean seasonal amplitudes always agree. The importance of abiotic influences such as the stratospheric influx and tropospheric transport on N[subscript 2]O seasonal cycles suggests that, at sites remote from local sources, surface N[subscript 2]O mixing ratio data by themselves are unlikely to provide information about seasonality in surface sources, e.g., for atmospheric inversions, unless the ACTMs employed in the inversions accurately account for these influences. An additional abioitc influence is the seasonal ingassing and outgassing of cooling and warming surface waters, which creates a thermal signal in tropospheric N[subscript 2]O that is of particular importance in the extratropical Southern Hemisphere, where it competes with the biological ocean source signal.United States. National Aeronautics and Space Administration (grant NNX08AB48G
Addition of serum-containing medium to cerebrospinal fluid prevents cellular loss over time
Immediately after sampling, leukocyte counts in native cerebrospinal fluid (CSF) start to decrease rapidly. As the time lapse between CSF collection to analysis is not routinely registered, the clinical significance of decreasing cell counts in native CSF is not known. Earlier data suggest that addition of serum-containing medium to CSF directly after sampling prevents this rapid decrease in leukocyte counts and, thus, may improve the accuracy of CSF cell counting and cell characterization. Here, we prospectively examined the effect of storage time after lumbar puncture on counts of leukocytes and their major subsets in both native CSF and after immediate addition of serum-containing medium, measured by flow cytometry and microscopy. We collected CSF samples of 69 patients in tubes with and tubes without serum-containing medium and determined counts of leukocytes and subsets at 30 minutes, 1 hour, and 5 hours after sampling. Compared to cell counts at 30 minutes, no significant decrease in cell number was observed in CSF with serum-containing medium 1 and 5 hours after sampling, except for the granulocytes at 1 hour. In native CSF, approximately 50% of leukocytes and all their subsets were lost after 1 hour, both in flow cytometric and microscopic counting. In 6/7 (86%) samples with mild pleocytosis (5–15 × 106 leukocytes/l), native CSF at 1 hour was incorrectly diagnosed as normocellular. In conclusion, addition of serum-containing medium to CSF directly after sampling prevents cell loss and allows longer preservation of CSF cells prior to analysis, both for microscopic and flow cytometric enumeration. We suggest that this protocol results in more accurate CSF cell counts and may prevent incorrect conclusions based on underestimated CSF cell counts
A molten salt test loop for component and instrumentation testing
Molten salt is an effective coolant for a wide range of applications, including nuclear reactors, concentrated solar power, and other high temperature industrial heat transfer processes. The technical readiness level of components and instrumentation for high-temperature molten salt applications needs improvement for molten salt to be more widely adopted. A molten salt test loop was designed, built, and commissioned as a test bed to address these issues. The molten salt test loop at Abilene Christian University was built out of 316 stainless steel with a forced flow centrifugal-type pump, and was instrumented for remote operation. A low-temperature molten nitrate salt was used in this system, which was designed to operate at temperatures up to 300 ◦C and flow rates up to 90 liters per minute.
This paper describes the loop design, computational fluid dynamics modeling, construction, and commissioning details. An outline of the data acquisition and control systems is presented. Salt samples were taken before and after introduction into the loop, and melting points were measured both before and after salt circulation. Performance of the system is discussed as well as improvements required for higher temperature loops envisioned for the future
Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context
Long noncoding RNAs (lncRNAs) are commonly dys-regulated in tumors, but only a handful are known toplay pathophysiological roles in cancer. We inferredlncRNAs that dysregulate cancer pathways, onco-genes, and tumor suppressors (cancer genes) bymodeling their effects on the activity of transcriptionfactors, RNA-binding proteins, and microRNAs in5,185 TCGA tumors and 1,019 ENCODE assays.Our predictions included hundreds of candidateonco- and tumor-suppressor lncRNAs (cancerlncRNAs) whose somatic alterations account for thedysregulation of dozens of cancer genes and path-ways in each of 14 tumor contexts. To demonstrateproof of concept, we showed that perturbations tar-geting OIP5-AS1 (an inferred tumor suppressor) andTUG1 and WT1-AS (inferred onco-lncRNAs) dysre-gulated cancer genes and altered proliferation ofbreast and gynecologic cancer cells. Our analysis in-dicates that, although most lncRNAs are dysregu-lated in a tumor-specific manner, some, includingOIP5-AS1, TUG1, NEAT1, MEG3, and TSIX, synergis-tically dysregulate cancer pathways in multiple tumorcontexts
Pan-cancer Alterations of the MYC Oncogene and Its Proximal Network across the Cancer Genome Atlas
Although theMYConcogene has been implicated incancer, a systematic assessment of alterations ofMYC, related transcription factors, and co-regulatoryproteins, forming the proximal MYC network (PMN),across human cancers is lacking. Using computa-tional approaches, we define genomic and proteo-mic features associated with MYC and the PMNacross the 33 cancers of The Cancer Genome Atlas.Pan-cancer, 28% of all samples had at least one ofthe MYC paralogs amplified. In contrast, the MYCantagonists MGA and MNT were the most frequentlymutated or deleted members, proposing a roleas tumor suppressors.MYCalterations were mutu-ally exclusive withPIK3CA,PTEN,APC,orBRAFalterations, suggesting that MYC is a distinct onco-genic driver. Expression analysis revealed MYC-associated pathways in tumor subtypes, such asimmune response and growth factor signaling; chro-matin, translation, and DNA replication/repair wereconserved pan-cancer. This analysis reveals insightsinto MYC biology and is a reference for biomarkersand therapeutics for cancers with alterations ofMYC or the PMN
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