740 research outputs found
Heterogeneous cancer-associated fibroblast population potentiates neuroendocrine differentiation and castrate resistance in a CD105-dependent manner.
Heterogeneous prostatic carcinoma-associated fibroblasts (CAF) contribute to tumor progression and resistance to androgen signaling deprivation therapy (ADT). CAF subjected to extended passaging, compared to low passage CAF, were found to lose tumor expansion potential and heterogeneity. Cell surface endoglin (CD105), known to be expressed on proliferative endothelia and mesenchymal stem cells, was diminished in high passage CAF. RNA-sequencing revealed SFRP1 to be distinctly expressed by tumor-inductive CAF, which was further demonstrated to occur in a CD105-dependent manner. Moreover, ADT resulted in further expansion of the CD105+ fibroblastic population and downstream SFRP1 in 3-dimensional cultures and patient-derived xenograft tissues. In patients, CD105+ fibroblasts were found to circumscribe epithelia with neuroendocrine differentiation. CAF-derived SFRP1, driven by CD105 signaling, was necessary and sufficient to induce prostate cancer neuroendocrine differentiation in a paracrine manner. A partially humanized CD105 neutralizing antibody, TRC105, inhibited fibroblastic SFRP1 expression and epithelial neuroendocrine differentiation. In a novel synthetic lethality paradigm, we found that simultaneously targeting the epithelia and its microenvironment with ADT and TRC105, respectively, reduced castrate-resistant tumor progression, in a model where either ADT or TRC105 alone had little effect
Suppression of Ornithine Decarboxylase Gene Expression by Retinoids in Cultured Human Keratinocytes
Modulation of ornithine decarboxylase (ODC) gene expression by retinoids was analyzed in human keratinocyte cultures maintained in serum-free medium containing 0.15mM Ca++. Cells were incubated with all-trans-retinoic acid, 13-cis-retinoic acid or arotinoid Ro15-0778 (10ā10 to 10ā5 M), total RNA was isolated, and mRNA transcripts for ODC were analyzed by Northern and slot blot hybridizations with a human ODC cDNA. Treatment of cells for 24h resulted in a dose-dependent decrease in ODC mRNA levels, with an estimated IC50 of ā¼1 Ć 10ā8 M for all-trans- and 13-cis-retinoic acid, while Ro15-0778 was somewhat less effective (IC50 ā¼1-5 Ć 10ā7 M). The suppression of ODC mRNA levels by retinoids was detectable at ā¼3h of incubation, with essentially a maximal inhibition at 12h. Reduced ODC mRNA levels noted after 24h of incubation with 5 Ć 10ā7 M all-trans-retinoic acid were accompanied by a reduction in ODC enzyme activity. To determine if all-trans-retinoic acid was regulating ODC gene expression directly, or if protein synthesis was required, ODC expression was analyzed in cultures treated with protein synthesis inhibitors. In the presence of cycloheximide or puromycin, all-trans-retinoic acid did not suppress ODC mRNA levels. These findings suggest that suppression of ODC gene expression is not a direct effect of all-trans-retinoic acid, but depends on ongoing protein synthesis
Multi-Elemental Analysis of Sandhills Meadow Hay
Traditionally, ranches in the Sandhills of Nebraska feed meadow hay to cows during the winter. Trace element composition of meadow hay varies. To determine if, when and where trace element supplementation is necessary, it is important to characterize the trace element concentrations in the hay. If the variation in trace element content of hay among location and years can be predicted ranch managers and advisors may develop appropriate strategies for sampling hay and preventing trace element deficiencies. Our objective was to develop a data base of trace element content of meadow hay from various locations over two years. The data base could be used to predict needs for sampling and supplementation strategies. appropriate strategies for sampling and supplementation strategies
Multi-Elemental Analysis of Sandhills Meadow Hay
Traditionally, ranches in the Sandhills of Nebraska feed meadow hay to cows during the winter. Trace element composition of meadow hay varies. To determine if, when and where trace element supplementation is necessary, it is important to characterize the trace element concentrations in the hay. If the variation in trace element content of hay among location and years can be predicted ranch managers and advisors may develop appropriate strategies for sampling hay and preventing trace element deficiencies. Our objective was to develop a data base of trace element content of meadow hay from various locations over two years. The data base could be used to predict needs for sampling and supplementation strategies. appropriate strategies for sampling and supplementation strategies
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Cancer epithelia-derived mitochondrial DNA is a targetable initiator of a paracrine signaling loop that confers taxane resistance.
Stromal-epithelial interactions dictate cancer progression and therapeutic response. Prostate cancer (PCa) cells were identified to secrete greater concentration of mitochondrial DNA (mtDNA) compared to noncancer epithelia. Based on the recognized coevolution of cancer-associated fibroblasts (CAF) with tumor progression, we tested the role of cancer-derived mtDNA in a mechanism of paracrine signaling. We found that prostatic CAF expressed DEC205, which was not expressed by normal tissue-associated fibroblasts. DEC205 is a transmembrane protein that bound mtDNA and contributed to pattern recognition by Toll-like receptor 9 (TLR9). Complement C3 was the dominant gene targeted by TLR9-induced NF-ĪŗB signaling in CAF. The subsequent maturation complement C3 maturation to anaphylatoxin C3a was dependent on PCa epithelial inhibition of catalase in CAF. In a syngeneic tissue recombination model of PCa and associated fibroblast, the antagonism of the C3a receptor and the fibroblastic knockout of TLR9 similarly resulted in immune suppression with a significant reduction in tumor progression, compared to saline-treated tumors associated with wild-type prostatic fibroblasts. Interestingly, docetaxel, a common therapy for advanced PCa, further promoted mtDNA secretion in cultured epithelia, mice, and PCa patients. The antiapoptotic signaling downstream of anaphylatoxin C3a signaling in tumor cells contributed to docetaxel resistance. The inhibition of C3a receptor sensitized PCa epithelia to docetaxel in a synergistic manner. Tumor models of human PCa epithelia with CAF expanded similarly in mice in the presence or absence of docetaxel. The combination therapy of docetaxel and C3 receptor antagonist disrupted the mtDNA/C3a paracrine loop and restored docetaxel sensitivity
Ultrasound-triggered antibiotic release from PEEK clips to prevent spinal fusion infection: Initial evaluations.
Despite aggressive peri-operative antibiotic treatments, up to 10% of patients undergoing instrumented spinal surgery develop an infection. Like most implant-associated infections, spinal infections persist through colonization and biofilm formation on spinal instrumentation, which can include metal screws and rods for fixation and an intervertebral cage commonly comprised of polyether ether ketone (PEEK). We have designed a PEEK antibiotic reservoir that would clip to the metal fixation rod and that would achieve slow antibiotic release over several days, followed by a bolus release of antibiotics triggered by ultrasound (US) rupture of a reservoir membrane. We have found using human physiological fluid (synovial fluid), that higher levels (100ā500 Ī¼g) of vancomycin are required to achieve a marked reduction in adherent bacteria vs. that seen in the common bacterial medium, trypticase soy broth. To achieve these levels of release, we applied a polylactic acid coating to a porous PEEK puck, which exhibited both slow and US-triggered release. This design was further refined to a one-hole or two-hole cylindrical PEEK reservoir that can clip onto a spinal rod for clinical use. Short-term release of high levels of antibiotic (340 Ā± 168 Ī¼g), followed by US-triggered release was measured (7420 Ā± 2992 Ī¼g at 48 h). These levels are sufficient to prevent adhesion of Staphylococcus aureus to implant materials. This study demonstrates the feasibility of an US-mediated antibiotic delivery device, which could be a potent weapon against spinal surgical site infection. Statement of Significance: Spinal surgical sites are prone to bacterial colonization, due to presence of instrumentation, long surgical times, and the surgical creation of a dead space (ā„5 cm 3 ) that is filled with wound exudate. Accordingly, it is critical that new approaches are developed to prevent bacterial colonization of spinal implants, especially as neither bulk release systems nor controlled release systems are available for the spine. This new device uses non-invasive ultrasound (US) to trigger bulk release of supra-therapeutic doses of antibiotics from materials commonly used in existing surgical implants. Thus, our new delivery system satisfies this critical need to eradicate surviving bacteria, prevent resistance, and markedly lower spinal infection rates
Effects of Supplementing High Levels of Cu, Co, Mn, and Zn After Calving on Productivity of Two-Year-Old Cows
When cow management, health and nutrition are adequate. supplementation of trace minerals at high levels is not beneficial and may in fact be detrimental to reproductive performance
Repetition Suppression and Reactivation in AuditoryāVerbal Short-Term Recognition Memory
The neural response to stimulus repetition is not uniform across brain regions, stimulus modalities, or task contexts. For instance, it has been observed in many functional magnetic resonance imaging (fMRI) studies that sometimes stimulus repetition leads to a relative reduction in neural activity (repetition suppression), whereas in other cases repetition results in a relative increase in activity (repetition enhancement). In the present study, we hypothesized that in the context of a verbal short-term recognition memory task, repetition-related āincreasesā should be observed in the same posterior temporal regions that have been previously associated with āpersistent activityā in working memory rehearsal paradigms. We used fMRI and a continuous recognition memory paradigm with short lags to examine repetition effects in the posterior and anterior regions of the superior temporal cortex. Results showed that, consistent with our hypothesis, the 2 posterior temporal regions consistently associated with working memory maintenance, also show repetition increases during short-term recognition memory. In contrast, a region in the anterior superior temporal lobe showed repetition suppression effects, consistent with previous research work on perceptual adaptation in the auditoryāverbal domain. We interpret these results in light of recent theories of the functional specialization along the anterior and posterior axes of the superior temporal lobe
Restriction fragment length polymorphisms distinguish among accessions of Ceratopteris thalictroides and C. richardii ( Parkeriaceae )
We have used cDNA clones as probes on Southern blots to detect restriction fragment length polymorphisms among seven Ceratopteris thalictroides accessions, three C. richardii accessions, and one putative interspecific hybrid. We found that the stringency of post-hybridization washes was a critical parameter affecting the quality of our blots; even with homologous cDNA sequences low stringency conditions resulted in a smear of signal, but high stringency washes gave blots with distinct bands. Most probes showed hybridization with four or more genomic fragments. Similarities in the number and size of fragments between and within species indicated that (i) C. richardii shows limited polymorphism among accessions tested, (ii) C. thalictroides is highly polymorphic, and (iii) Hawaiian accessions of C. thalictroides are divergent relative to their continental cohorts and among themselves. The putative interspecific hybrid did not group closely with either of these species.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41637/1/606_2004_Article_BF00939725.pd
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