Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment

On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G_{target} of 1.5. This is the first laboratory demonstration of exceeding "scientific breakeven" (or G_{target}>1) where 2.05 MJ of 351 nm laser light produced 3.1 MJ of total fusion yield, a result which significantly exceeds the Lawson criterion for fusion ignition as reported in a previous NIF implosion [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129, 075001 (2022)PRLTAO0031-900710.1103/PhysRevLett.129.075001]. This achievement is the culmination of more than five decades of research and gives proof that laboratory fusion, based on fundamental physics principles, is possible. This Letter reports on the target, laser, design, and experimental advancements that led to this result.

Upregulation of the EGFR/MEK1/MAPK1/2 signaling axis as a mechanism of resistance to antiestrogen‑induced BimEL dependent apoptosis in ER+ breast cancer cells

The epidermal growth factor receptor (EGFR) is commonly upregulated in multiple cancer types, including breast cancer. In the present study, evidence is provided in support of the premise that upregulation of the EGFR/MEK1/MAPK1/2 signaling axis during antiestrogen treatment facilitates the escape of breast cancer cells from BimEL‑dependent apoptosis, conferring resistance to therapy. This conclusion is based on the findings that ectopic BimEL cDNA overexpression and confocal imaging studies confirm the pro‑apoptotic role of BimEL in ERα expressing breast cancer cells and that upregulated EGFR/MEK1/MAPK1/2 signaling blocks BimEL pro‑apoptotic action in an antiestrogen‑resistant breast cancer cell model. In addition, the present study identified a pro‑survival role for autophagy in antiestrogen resistance while EGFR inhibitor studies demonstrated that a significant percentage of antiestrogen‑resistant breast cancer cells survive EGFR targeting by pro‑survival autophagy. These pre‑clinical studies establish the possibility that targeting both the MEK1/MAPK1/2 signaling axis and pro‑survival autophagy may be required to eradicate breast cancer cell survival and prevent the development of antiestrogen resistance following hormone treatments. The present study uniquely identified EGFR upregulation as one of the mechanisms breast cancer cells utilize to evade the cytotoxic effects of antiestrogens mediated through BimEL‑dependent apoptosis.

Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion.

An essential role of Ffar2 (Gpr43) in dietary fibre-mediated promotion of healthy composition of gut microbiota and suppression of intestinal carcinogenesis

Composition of the gut microbiota has profound effects on intestinal carcinogenesis. Diet and host genetics play critical roles in shaping the composition of gut microbiota. Whether diet and host genes interact with each other to bring specific changes in gut microbiota that affect intestinal carcinogenesis is unknown. Ability of dietary fibre to specifically increase beneficial gut microbiota at the expense of pathogenic bacteria in vivo via unknown mechanism is an important process that suppresses intestinal inflammation and carcinogenesis. Free fatty acid receptor 2 (FFAR2 or GPR43) is a receptor for short-chain fatty acids (acetate, propionate and butyrate), metabolites of dietary fibre fermentation by gut microbiota. Here, we show FFAR2 is down modulated in human colon cancers than matched adjacent healthy tissue. Consistent with this, Ffar2(-/-) mice are hypersusceptible to development of intestinal carcinogenesis. Dietary fibre suppressed colon carcinogenesis in an Ffar2-dependent manner. Ffar2 played an essential role in dietary fibre-mediated promotion of beneficial gut microbiota, Bifidobacterium species (spp) and suppression of Helicobacter hepaticus and Prevotellaceae. Moreover, numbers of Bifidobacterium is reduced, whereas those of Prevotellaceae are increased in human colon cancers than matched adjacent normal tissue. Administration of Bifidobacterium mitigated intestinal inflammation and carcinogenesis in Ffar2(-/-) mice. Taken together, these findings suggest that interplay between dietary fibre and Ffar2 play a key role in promoting healthy composition of gut microbiota that stimulates intestinal health.

Abstract 1005: Dual targeting of MEK/MAPK1/2 and pro-survival autophagy to optimize antiestrogen treatment toward the eradication of antiestrogen resistant breast cancer

In past studies, we showed that pro-survival autophagy mediates resistance to antiestrogen-induced apoptosis and facilitates the emergence of antiestrogen resistant breast cancer cells (Sammadar et al., Molecular Cancer Ther. 9, 2008). We also identified the pro-apoptotic BimEL protein as a key death effector of antiestrogen treatment and determined that BimEL pro-apoptotic activity is abrogated by a MEK1/MAPK1/2-dependent phosphorylation (Periyasamy-Thandavan et al., Breast Cancer Res. 14, 2012). In this study, we tested the hypothesis that the MEK1/MAPK1/2/BimEL signaling node simultaneously regulates antiestrogen- induced pro-survival autophagy and apoptosis in ER+ breast cancer cells. In our approach, we utilized T47-D and MCF-7 breast cancer cells and modulated the activity of MEK1/MAPK1/2/ BimEL expression with U0126, a small molecule inhibitor of MEK1, BimEL cDNA over-expression, or siRNA targeting under a variety of endocrine treatments. We also conducted studies in the presence or absence of the pan-caspase inhibitor ZVAD-fmk so that autophagy levels/function could be analyzed independent of effects mediated by BimEL-dependent caspase activation. Autophagic flux was measured by comparing the levels of lipidated LC3II in cell populations undergoing the different treatments in the presence or absence of chloroquine (CQ), a lysosomotropic agent that prevents autolysosomal turnover. These studies determined that: 1) dephosphorylated BimEL significantly attenuates autophagic flux, but primarily as a consequence of BimEL-induced caspase-activation; (2) BimEL-dependent apoptotic death induced in antiestrogen-treated ER+ breast cancer cells by MEK1 inhibition is not dependent on autophagy; and (3) agents that selectively target autophagy (i.e. CQ and spautin) enhance apoptosis induced by MEK1 blockade in breast cancer cells undergoing endocrine treatment. Based on these pre-clinical in vitro studies, we postulate that the eradication of antiestrogen resistant breast cancer will require the targeting of MEK1/MAPK1/2 to activate BimEL and pro-survival autophagy to eradicate cells surviving BimEL-dependent apoptosis.

Citation Format: Mathew Manning, Suchreet Takhar, Sudharsan Periyasamy-Thandavan, Michael Cheng, Thomas Barrett, William Hill, Darren Browning, Muthusamy Thangaraju, Meghan McGee-Lawrence, Patricia V. Schoenlein. Dual targeting of MEK/MAPK1/2 and pro-survival autophagy to optimize antiestrogen treatment toward the eradication of antiestrogen resistant breast cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1005. doi:10.1158/1538-7445.AM2015-1005

Systematic review and critical appraisal of the impact of acellular dermal matrix use on the outcomes of implant-based breast reconstruction

BACKGROUND

Acellular dermal matrix (ADM) may improve outcomes in implant-based breast reconstruction (IBBR). The aim of this study was critically to appraise and evaluate the current evidence for ADM-assisted IBBR.

METHODS

Comprehensive electronic searches identified complete papers published in English between January 2000 and August 2013, reporting any outcome of ADM-assisted IBBR. All systematic reviews, randomized clinical trials (RCTs) and non-randomized studies (NRSs) with more than 20 ADM recipients were included. Studies were critically appraised using AMSTAR for systematic reviews, the Cochrane risk-of-bias tool for RCTs and its adaptation for NRSs. Characteristics and results of identified studies were summarized.

RESULTS

A total of 69 papers (8 systematic reviews, 1 RCT, 40 comparative studies and 20 case series) were identified, all of which were considered at high risk of bias, mostly due to patient selection and selective outcome reporting. The median ADM group sample size was 51.0 (i.q.r. 33.0-127.0). Most studies were single-centre (54), and they were often single-surgeon (16). ADM was most commonly used for immediate (40) two-stage IBBR (36) using human ADM (47), with few studies evaluating ADM-assisted single-stage procedures (10). All reported clinical outcomes (for example implant loss) and more than half of the papers (33) assessed process outcomes, but few evaluated cosmesis (16) or patient-reported outcomes (10). Heterogeneity between study design and, especially, outcome measurement precluded meaningful data synthesis.

CONCLUSION

Current evidence for the value of ADMs in IBBR is limited. Use in practice should therefore be considered experimental, and evaluation within registries or well designed and conducted studies, ideally RCTs, is recommended to prevent widespread adoption of a potentially inferior intervention.

Curcumin inhibits PhIP induced cytotoxicity in breast epithelial cells through multiple molecular targets

Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), found in cooked meat, is a known food carcinogen that causes several types of cancer, including breast cancer, as PhIP metabolites produce DNA adduct and DNA strand breaks. Curcumin, obtained from the rhizome of Curcuma longa, has potent anticancer activity. To date, no study has examined the interaction of PhIP with curcumin in breast epithelial cells. The present study demonstrates the mechanisms by which curcumin inhibits PhIP-induced cytotoxicity in normal breast epithelial cells (MCF-10A). Curcumin significantly inhibited PhIP-induced DNA adduct formation and DNA double stand breaks with a concomitant decrease in reactive oxygen species (ROS) production. The expression of Nrf2, FOXO targets; DNA repair genes BRCA-1, H2AFX and PARP-1; and tumor suppressor P16 was studied to evaluate the influence on these core signaling pathways. PhIP induced the expression of various antioxidant and DNA repair genes. However, co-treatment with curcumin inhibited this expression. PhIP suppressed the expression of the tumor suppressor P16 gene, whereas curcumin co-treatment increased its expression. Caspase-3 and -9 were slightly suppressed by curcumin with a consequent inhibition of cell death. These results suggest that curcumin appears to be an effective anti-PhIP food additive likely acting through multiple molecular targets.

Abstract B50: MEK inhibitors mount a two-pronged attack to kill estrogen receptor positive (ER+) breast cancer cells undergoing hormonal therapy: Attenuated autophagy and induction of apoptosis

In a recent study, we identified the dephosphorylated form of BimEL as a key death effector of antiestrogen treatment of ER+ breast cancer cells and further showed that MEK1/MAPK1/2 blockade was required to produce high levels of dephosphorylated BimEL, particularly under conditions of insulin like growth factor 1 (IGF1) stimulation (Periyasamy-Thandavan et al., Breast Cancer Res. 14, 2012). Studies by others have identified MEK1/MAPK1/2 activation as essential to autophagy, a catabolic process induced by multiple stresses including ROS, ceramide accumulation, and nutrient deprivation. Autophagy induction results in autophagosome formation, trafficking of damaged proteins and mitochondria to the autophagosomes, and ultimately fusion with the lysosomes resulting in autolysosome formation. The autolysosome and its contents are degraded by the hydrolytic enzymes of the lysosome. Of particular interest to antiestrogen treatment of breast cancer, we and others have shown that pro-survival autophagy facilitates the emergence of antiestrogen resistant breast cancer cells. Thus, we are keenly interested in how MEK1/MAPK1/2 signaling affects pro-survival autophagy and if MEK blockade would be an effective approach toward blocking pro-survival autophagy in ER+ breast cancer cells undergoing hormonal treatment. In this study, we hypothesized that the requirement of MEK1/MAPK1/2 for pro-survival autophagy is due, in part, to its role in blocking the intracellular accumulation of dephosphorylated BimEL. To test this hypothesis, we modulated the expression of dephosphorylated BimEL with either a BimEL cDNA expression vector, siRNA targeting of BimEL, or MEK1 blockade with the small molecule inhibitor U0126 and determined the levels of the autophagic flux in ER+ breast cancer cells undergoing antiestrogen treatment. The determination of autophagic flux was made by comparing the levels of two proteins involved in autophagy -the LC3 /Atg8 and p62 (SQSTM1) proteins- in cell populations undergoing the different treatments in the presence or absence of chloroquine (CQ). The lipidated form of LC3, designated LC3II, is typically increased in cells undergoing autophagy, facilitates the formation of the mature autophagosomal membranes, and is subsequently degraded in the autolysosome. The p62 protein is required for the delivery of ubiquitinated protein complexes to the autophagosome and is degraded along with the ubiquitinated complex of proteins. CQ is a lysosomotrophic agent routinely used in autophagic flux assays because it blocks the turnover of autolysosomes with accumulation of LC3 II and p62, allowing the total levels of LC3II and p62 to be ascertained under all treatment conditions. These studies showed that siRNA targeting of BimEL increased basal and tamoxifen-induced autophagy in ER+ MCF-7 breast cancer cells. In contrast, the overexpression of dephosphorylated BimEL led to an increase in LC3 II and p62 levels due to a significant attenuation of autophagic flux (approximately 50%) in antiestrogen-treated cell populations. Current studies are focused on the mechanism of BimEL-mediated blockade of pro-survival autophagy, with the long term goal of optimizing this “downstream effector” function of MEK1/MAPK1/2 blockade in ER+ breast cancer cells for improved therapeutic outcome.

Citation Format: S. Takhar, M. Manning, A. Eason, M. Dix, S. Periyasamy-Thandavan, R. Padi, E. Bieberich, W. Hill, D. Browning, V. Ganapathy, M. Thangaraju, P. V. Schoenlein. MEK inhibitors mount a two-pronged attack to kill estrogen receptor positive (ER+) breast cancer cells undergoing hormonal therapy: Attenuated autophagy and induction of apoptosis. [abstract]. In: Proceedings of the AACR Special Conference on RAS Oncogenes: From Biology to Therapy; Feb 24-27, 2014; Lake Buena Vista, FL. Philadelphia (PA): AACR; Mol Cancer Res 2014;12(12 Suppl):Abstract nr B50. doi: 10.1158/1557-3125.RASONC14-B50

IFN-γ activates p300 to over-ride silencing effects of DNA methylation to activate GPR109A and SLC5A8 transcription (P2105)

Short-chain fatty acids, metabolites produced by colonic microbiota from fermentation of dietary fiber, act as anti-inflammatory agents in the intestinal tract to suppress inflammation-mediated diseases such as inflammatory bowel disease and colorectal cancer. GPR109A and SLC5A8, receptor and transporter, respectively, for short chain fatty acids, are often silenced in human colon carcinoma cells. We demonstrated that the GPR109A and SLC5A8 promoter DNA is hypermethylated in human colon carcinoma cells in vitro and in vivo. Strikingly, IFN-γ, a cytokine secreted by activated cytotoxic T lymphocytes, effectively activated GPR109A and SLC5A8 transcription without altering their promoter DNA methylation levels. Analysis of the IFN-γ signaling pathways indicated that IFN-γ-activated pSTAT1 binds to the promoter of immediate early target gene p300 to rapidly activate p300 transcription. p300 then binds to the GPR109A and SLC5A8 promoters and induces chromatin hyperacetylation, resulting in chromatin remodeling in the hypermethylated GPR109A and SLC5A8 promoter regions. pSTAT1 then directly binds to the remodeled but still hypermethylated GPR109A and SLC5A8 promoters to activate transcription of secondary response genes GPR109A and SLC5A8. Taken together, our data suggest that the host immune system might use IFN-γ to counteract DNA methylation-mediated silencing of tumor suppressor genes as a mechanism to suppress tumor development.

High performance imaging streak camera for the National Ignition Facility

An x-ray streak camera platform has been characterized and implemented for use at the National Ignition Facility. The camera has been modified to meet the experiment requirements of the National Ignition Campaign and to perform reliably in conditions that produce high electromagnetic interference. A train of temporal ultra-violet timing markers has been added to the diagnostic in order to calibrate the temporal axis of the instrument and the detector efficiency of the streak camera was improved by using a CsI photocathode. The performance of the streak camera has been characterized and is summarized in this paper. The detector efficiency and cathode measurements are also presented.

X-ray streak camera cathode development and timing accuracy of the 4ω ultraviolet fiducial system at the National Ignition Facility

The convergent ablator experiments at the National Ignition Facility (NIF) are designed to measure the peak velocity and remaining ablator mass of an indirectly driven imploding capsule. Such a measurement can be performed using an x-ray source to backlight the capsule and an x-ray streak camera to record the capsule as it implodes. The ultimate goal of this experiment is to achieve an accuracy of 2% in the velocity measurement, which translates to a ±2 ps temporal accuracy over any 300 ps interval for the streak camera. In order to achieve this, a 4ω (263 nm) temporal fiducial system has been implemented for the x-ray streak camera at NIF. Aluminum, titanium, gold, and silver photocathode materials have been tested. Aluminum showed the highest relative quantum efficiency, with five times more peak signal counts per fiducial pulse when compared to Gold. The fiducial pulse data were analyzed to determine the centroiding statistical accuracy for incident laser pulse energies of 1 and 10 nJ, showing an accuracy of ±1.6 ps and ±0.7 ps, respectively.

IFN-γ upregulates survivin and Ifi202 expression to induce survival and proliferation of tumor-specific T cells

BACKGROUND

A common procedure in human cytotoxic T lymphocyte (CTL) adoptive transfer immunotherapy is to expand tumor-specific CTLs ex vivo using CD3 mAb prior to transfer. One of the major obstacles of CTL adoptive immunotherapy is a lack of CTL persistence in the tumor-bearing host after transfer. The aim of this study is to elucidate the molecular mechanisms underlying the effects of stimulation conditions on proliferation and survival of tumor-specific CTLs.

METHODOLOGY/PRINCIPAL FINDINGS

Tumor-specific CTLs were stimulated with either CD3 mAb or cognate Ag and analyzed for their proliferation and survival ex vivo and persistence in tumor-bearing mice. Although both Ag and CD3 mAb effectively induced the cytotoxic effecter molecules of the CTLs, we observed that Ag stimulation is essential for sustained CTL proliferation and survival. Further analysis revealed that Ag stimulation leads to greater proliferation rates and less apoptosis than CD3 mAb stimulation. Re-stimulation of the CD3 mAb-stimulated CTLs with Ag resulted in restored CTL proliferative potential, suggesting that CD3 mAb-induced loss of proliferative potential is reversible. Using DNA microarray technology, we identified that survivin and ifi202, two genes with known functions in T cell apoptosis and proliferation, are differentially induced between Ag- and CD3 mAb-stimulated CTLs. Analysis of the IFN-γ signaling pathway activation revealed that Ag stimulation resulted in rapid phosphorylation of STAT1 (pSTAT1), whereas CD3 mAb stimulation failed to activate STAT1. Chromatin immunoprecipitation revealed that pSTAT1 is associated with the promoters of both survivin and ifi202 in T cells and electrophoresis mobility shift assay indicated that pSTAT1 directly binds to the gamma activation sequence element in the survivin and ifi202 promoters. Finally, silencing ifi202 expression significantly decreased T cell proliferation.

CONCLUSIONS/SIGNIFICANCE

Our findings delineate a new role of the IFN-γ signaling pathway in regulating T cell proliferation and apoptosis through upregulating survivin and ifi202 expression.

Abstract 4845: TONDU, a transcription factor that regulates prosurvival autophagy and the development of antiestrogen resistance in breast cancer

In recent studies, we have demonstrated that autophagy is essential for the survival of estrogen receptor positive (ER+) breast cancer cells during anti-estrogen therapy and facilitates the development of antiestrogen resistance. For these studies, we subjected ER+ MCF-7 cells to a step-wise drug selection protocol, with 4 hydroxytamoxifen (4-OHT) as the selecting drug and established an antiestrogen resistant subline, designated TR5 (4-OHT resistant to 5μM). TR5 cells, unlike the parent MCF-7 cells, do not die in response to 4-OHT treatment and tolerate high levels of antiestrogen-induced autophagosome formation. Microarray analysis of 4-OHT-treated TR5 cells shows an approximate 5-10 -fold increase in TONDU (TDU) mRNA compared to that of the parent MCF-7 cells. TDU, also known as vestigial like gene-1, was initially identified as a transcription factor required for wing development in Drosophilia, but specific roles for TDU in mammalian cells have not been identified. Based on the upregulation of TDU in antiestrogen-resistant TR5 cells, we hypothesized that TDU played a role in pro-survival autophagy. To test this hypothesis, we analyzed the levels of TDU in cultured MCF-7 and TR5 cells under conditions that induce autophagy and further determined how modulation of TDU levels (TDU cDNA overexpression and TDU attenuation by RNAi targeting) affected autophagy and death. 4-OHT and rapamycin, an mTOR inhibitor that induces macroautophagy, increased TDU expression within 24 hours of treatment and increased TDU expression persisted for 96 hours. Further, quantitative Real-Time (RT) PCR analysis of cells overexpressing TDU revealed that TDU upregulated the transcription of autophagy genes (i.e. upregulation of LC3, Atg5 and Atg6). Importantly, the TDU-mediated increased expression of autophagy genes was blocked by TDU RNAi. Consistent with this apparent TDU-induced autophagy, TDU overexpression significantly increased autophagic proteolysis (long-lived protein turnover). In addition, down regulation of TDU by RNAi induced cell death in E2- and 4-OHT-treated MCF-7 and TR5 cells, with increased mitochondrial membrane permeability, cleavage of PARP, and cleavage of lamin-A as read-outs of cell death. To our knowledge, these studies uniquely identify TDU as a transcription factor involved in the regulation of autophagy in ER+ breast cancer cells and as a potential molecular target to block pro-survival autophagy and enhance the cytotoxicity of antiestrogen therapy. Our current studies are aimed at determining whether TDU expression levels can serve as a prognostic indicator of breast cancer response to hormonal therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4845.

A role for macroautophagy in protection against 4-hydroxytamoxifen-induced cell death and the development of antiestrogen resistance

This study identifies macroautophagy as a key mechanism of cell survival in estrogen receptor-positive (ER+) breast cancer cells undergoing treatment with 4-hydroxytamoxifen (4-OHT). This selective ER modifier is an active metabolite of tamoxifen commonly used for the treatment of breast cancer. Our study provides the following key findings: (a) only 20% to 25% of breast cancer cells treated with 4-OHT in vitro die via caspase-dependent cell death; more typically, the antiestrogen-treated ER+ breast cancer cells express increased levels of macroautophagy and are viable; (b) 4-OHT-induced cell death, but not 4-OHT-induced macroautophagy, can be blocked by the pan-caspase inhibitor z-VAD-fmk, providing strong evidence that these two outcomes of antiestrogen treatment are not linked in an obligatory manner; (c) 4-OHT-resistant cells selected from ER+ breast cancer cells show an increased ability to undergo antiestrogen-induced macroautophagy without induction of caspase-dependent cell death; and (d) 4-OHT, when used in combination with inhibitors of autophagosome function, induces robust, caspase-dependent apoptosis of ER+, 4-OHT-resistant breast cancer cells. To our knowledge, these studies provide the first evidence that macroautophagy plays a critical role in the development of antiestrogen resistance. We propose that targeting autophagosome function will improve the efficacy of hormonal treatment of ER+ breast cancer.

Robotic pyeloplasty using internet protocol and satellite network-based telesurgery

BACKGROUND

In North America, the urological community has embraced surgical robotic technology in the performance of complex laparoscopic surgery. The performance of complex long-distance telesurgery requires further investigation prior to clinical application.

METHODS

The feasibility of laparoscopic robot-assisted pyeloplasty in a porcine model was assessed using the Zeus robot and the internet protocol virtual private network (IP-VPNe) and satellite links. Eighteen pyeloplasty procedures were performed, using real-time, IP-VPNe and satellite network connection (six of each). Network and objective operative data were collected.

RESULTS

Despite network delays and jitter, it was feasible to perform the pyeloplasty procedure without significant detriment in operative time or surgical results compared with real-time surgery.

CONCLUSION

The completion of complex tasks such as robotic pyeloplasty is feasible using both land-line and satellite telesurgery. However, the clinical relevance of telesurgery requires further assessment.

Randomized trial of peribulbar triamcinolone acetonide with and without focal photocoagulation for mild diabetic macular edema: a pilot study

OBJECTIVE

To provide pilot data on the safety and efficacy of anterior and posterior sub-Tenon injections of triamcinolone either alone or in combination with focal photocoagulation in the treatment of mild diabetic macular edema (DME).

DESIGN

Prospective, phase II, multicenter, randomized clinical trial.

PARTICIPANTS

One hundred nine patients (129 eyes) with mild DME and visual acuity 20/40 or better.

METHODS

The participants were assigned randomly to receive either focal photocoagulation (n = 38), a 20-mg anterior sub-Tenon injection of triamcinolone (n = 23), a 20-mg anterior sub-Tenon injection followed by focal photocoagulation after 4 weeks (n = 25), a 40-mg posterior sub-Tenon injection of triamcinolone (n = 21), or a 40-mg posterior sub-Tenon injection followed by focal photocoagulation after 4 weeks (n = 22). Follow-up visits were performed at 4, 8, 17, and 34 weeks.

MAIN OUTCOME MEASURES

Change in visual acuity and retinal thickness measured with optical coherence tomography (OCT).

RESULTS

At baseline, mean visual acuity in the study eyes was 20/25 and mean OCT central subfield thickness was 328 mum. Changes in retinal thickening and in visual acuity were not significantly different among the 5 groups at 34 weeks (P = 0.46 and P = 0.94, respectively). There was a suggestion of a greater proportion of eyes having a central subfield thickness less than 250 mum at 17 weeks when the peribulbar triamcinolone was combined with focal photocoagulation. Elevated intraocular pressure and ptosis were adverse effects attributable to the injections.

CONCLUSIONS

In cases of DME with good visual acuity, peribulbar triamcinolone, with or without focal photocoagulation, is unlikely to be of substantial benefit. Based on these results, a phase III trial to evaluate the benefit of these treatments for mild DME is not warranted.

Phosphorylation of beta-catenin by cyclic AMP-dependent protein kinase

Beta-catenin is a signaling molecule that promotes cell proliferation by the induction of gene transcription through the activation of T-cell factor (TCF)/lymphoid enhancer factor (LEF) transcription factors. The canonical mechanism of the regulation of beta-catenin involves its phosphorylation by casein kinase 1 at the Ser-45 site and by glycogen synthase kinase 3 (GSK3) at the Thr-41, Ser-37, and Ser-33 sites. This phosphorylation targets beta-catenin to ubiquitination and degradation by the proteasome system. Mitogenic factors promote beta-catenin signaling through the inhibition of GSK3, resulting in reduced beta-catenin phosphorylation, its stabilization, and subsequent accumulation in the nucleus, where it stimulates TCF/LEF-dependent gene transcription. In the present study, we have shown that (i) beta-catenin can be phosphorylated by protein kinase A (PKA) in vitro and in intact cells at two novel sites, Ser-552 and Ser-675; (ii) phosphorylation by PKA promotes the transcriptional activity (TCF/LEF transactivation) of beta-catenin; (iii) mutation of Ser-675 attenuates the promoting effect of PKA; (iv) phosphorylation by PKA does not affect the GSK3-dependent phosphorylation of beta-catenin, its stability, or intracellular localization; and (v) phosphorylation at the Ser-675 site promotes the binding of beta-catenin to its transcriptional coactivator, CREB-binding protein. In conclusion, this study identifies a novel, noncanonical mechanism of modulation of beta-catenin signaling through direct phosphorylation of beta-catenin by PKA, promoting its interaction with CREB-binding protein.

An anti-tumor role for cGMP-dependent protein kinase

This study compared Type-1 cGMP-dependent protein kinase (PKG) expression in normal and tumor tissues and examined PKG function in tumor growth. Studies with a cDNA array revealed that PKG expression was reduced in many tumors compared to respective normal tissue. This decrease in PKG expression was confirmed using quantitative RT-PCR and western blotting of matched colon specimens from normal epithelium and tumor tissue, and also in colon derived cell lines where luciferase reporter analysis revealed that the decreased expression occurred at the transcriptional level. Using SW620 colon carcinoma cells engineered for inducible expression of PKG1beta, it was found that exogenous PKG1beta lead to decreased tumor growth and invasiveness in nude mouse xenografts.

Switching patients with migraine from sumatriptan to other triptans increases primary care costs

Treatment of migraine with triptans is highly effective, although cost considerations may prompt a change in therapy. This retrospective database analysis of 3196 patients with migraine, established on sumatriptan therapy, found that 54% of the 292 experiencing a triptan switch returned to sumatriptan within 15 months, suggesting that the alternative was less acceptable. Excluding patients with unusually high use of triptans (> or = 208 tablets/year), switching therapy resulted in a significant increase of pounds sterling 53/patient in total costs, compared with patients continuing on sumatriptan (p = 0.014). Cost savings (pounds sterling 17/patient over 15 months) were observed only among the 41% of patients in whom the initial switch was successful and did not result in a further switch or return to sumatriptan. Among patients who were relatively low cost initially, switching resulted in increased costs, irrespective of the outcome. This study suggests that there is no economic justification for switching from sumatriptan to another triptan.

Bupropion as an aid to smoking cessation: a review of real-life effectiveness

Clinical trials rigorously demonstrate the efficacy of new products and justify their marketing. However, it is only after use in real-life settings that the clinical value (effectiveness) of a new treatment is fully known. The purpose of this review was to summarise the effectiveness data for bupropion SR as an aid to smoking cessation. Available reports of effectiveness data for bupropion SR were obtained from the literature, presentations at smoking cessation meetings and from the manufacturer. Twelve sources of effectiveness data were found and included clinical practice trials, observational studies/surveys, motivational support programme results and employer-based cessation programme results. The 6-month point prevalence smoking cessation rates ranged from 25 to 49%. There is a growing body of evidence supporting the effectiveness of bupropion SR as an aid to smoking cessation. Real-life quit rates for bupropion SR are similar to those seen in the original clinical trial programme.

Functional significance of protein kinase A activation by endothelin-1 and ATP: negative regulation of SRF-dependent gene expression by PKA

Endothelin-1 (ET1) and ATP stimulate contraction and hypertrophy of vascular smooth muscle cells (VSMC) by activating diverse signalling pathways. In this study, we show that in VSMC, ET1 and ATP stimulate transient and sustained activation of protein kinase A (PKA), respectively. Using a dominant negative PKA mutant (PKA-DN), we examined the functional significance of PKA activation in the signalling of ET1 and ATP. Overexpression of PKA-DN did not alter the ET1- or ATP-induced phosphorylation of the extracellular signal-regulated protein kinase, Erk2. ATP stimulated a profound, PKA-dependent activation of cAMP-response element (CRE), whereas the effect of ET1 was negligible. Both ET1 and ATP stimulated serum response factor (SRF)-dependent gene expression. Overexpression of PKA-DN potentiated the effects of ET1 and ATP on SRF activity, whereas stimulation of PKA by isoproterenol, forskolin or by overexpression of the PKA catalytic subunit decreased SRF activity. These data demonstrate that (i) PKA negatively regulates SRF activity and (ii) ET1 and ATP stimulate opposing pathways, whose balance determines the net activity of SRF.

Addition of salmeterol to fluticasone propionate treatment in moderate-to-severe asthma

This study was designed to determine whether the benefit of adding salmeterol was superior to doubling the dose of fluticasone propionate (FP) over 6 months, compared to a control group who remained on a lower dose of FP. The multi-centre, double-blind, parallel group study involved 496 symptomatic asthmatic patients with a history of exacerbations on 500-800 micrograms (microg) inhaled corticosteroids (ICS) twice daily (b.d.) in a broadly representative group of 100 hospitals and general practices in six countries. Two doses of FP--250 microg b.d. (FP250) or 500 microg b.d. (FP500)--were compared with the lower dose of FP plus a long-acting beta2-agonist, salmeterol 50 microg b.d. (SM/FP250). Patients symptomatic on the run-in dose of FP250 alone formed the control group in the treatment period. Over 6 months, SM/FP250 significantly improved mean morning peak expiratory flow rates (amPEF) by 42.1 l/min, more than twice the improvement achieved with either dose of FP alone. SM/FP250 also resulted in more symptom-free days and nights (P < 0.002) and days and nights with no relief medication (P < 0.001). The number of severe exacerbations was low: 3, 6 and 8% in the SM/FP250, low- and high-dose FP groups, respectively. This study confirms that adding salmeterol to low-dose inhaled FP offers greater improvements than either maintaining or doubling the dose of FP. Significant benefit was gained from adding salmeterol in a group of patients who appeared to have been at the top of their steroid dose-response curve receiving FP250. There was no evidence of tolerance and a low incidence of exacerbations in all treatment groups.

Activation of the mitogen activated protein kinase extracellular signal-regulated kinase 1 and 2 by the nitric oxide-cGMP-cGMP-dependent protein kinase axis regulates the expression of matrix metalloproteinase 13 in vascular endothelial cells

Matrix metalloproteinases (MMPs) are synthesized in response to diverse stimuli, including cytokines, growth factors, hormones, and oxidative stress. Here we show that the nitric oxide (NO) donor 2-(N,N-diethylamino)-diazenolate-2-oxide (DEA-NO) and NO from murine macrophages transcriptionally regulate MMP-13 expression in vascular endothelial cells (BAEC). The cGMP analog, 8-bromo-cGMP (8-Br-cGMP) mimicked the effect of NO, whereas incubation with the guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, or the cGMP-dependent protein kinase (PKG) inhibitor phenyl-1,N (2)- etheno-8-bromoguanosine-3',5'-cyclic monophosphorothioate, Rp-isomer (PET) reduced the stimulatory effect of DEA-NO on the activation of the MMP-13 promoter. Overexpression of the catalytic subunit of PKG1-alpha resulted in a 5- to 6-fold increase of the MMP-13 regulatory region over control cells. On the other hand, incubation with the mitogen-activated protein/extracellular signal-regulated kinase inhibitor 2'-amino-3'-methoxyflavone (PD98059) significantly reduced DEA-NO and 8-Br-cGMP promoter activation and mRNA expression of MMP-13 in transfected BAEC. Moreover, a complex between PKG1-alpha and the G-protein Raf-1, an upstream activator of the extracellular signal-regulated kinase signaling pathway, was detected in cells overexpressing PKG1-alpha or treated either with DEA-NO or 8-Br-cGMP. Thus, we propose that the NO-cGMP-PKG pathway enhances MMP-13 expression by the activation of ERK 1,2. This effect of NO may be important in the context of pathophysiological conditions such as inflammation or atherogenesis [corrected].

Differential gene expression between normal and tumor-derived ovarian epithelial cells

The majority of ovarian tumors arise from the transformation of the ovarian surface epithelial cells, a single layer of cells surrounding the ovary. To identify genes that may contribute to the malignant phenotype of ovarian cancers, cDNA representational difference analysis was used to compare expressed genes in primary cultures of normal human ovarian surface epithelium (HOSE) and ovarian tumor-derived epithelial cells from the Cedars-Sinai Ovarian Cancer (CSOC) repository. A total of 255 differentially expressed genes were identified, of which 160 and 95 were specifically expressed in HOSE and CSOC cells, respectively. Using cDNA array hybridization, the expression profiles of the genes identified by cDNA-representational difference analysis were examined in an additional 5 HOSE and 10 CSOC lines. The comparison of average signal of each gene revealed 44 HOSE-specific and 16 CSOC-specific genes that exhibited at least a 2.5-fold difference in expression. A large number of genes identified in this study encode membrane-associated or secreted proteins and, hence, may be useful as targets in the development of serum-based diagnostic markers for ovarian cancer. Very few genes associated with protein synthesis or metabolism were identified in this study, reflecting the lack of observable differences in phenotypic or growth characteristics between HOSE and CSOC cells. Northern blot analysis on a subset of these genes demonstrated comparable levels of gene expression as observed in the cDNA array hybridization.

Notch signaling enhances survival and alters differentiation of 32D myeloblasts

The Notch transmembrane receptors play important roles in precursor survival and cell fate specification during hematopoiesis. To investigate the function of Notch and the signaling events activated by Notch in myeloid development, we expressed truncated forms of Notch1 or Notch2 proteins that either can or cannot activate the core binding factor 1 (CBF1) in 32D (clone 3) myeloblasts. 32D cells proliferate as blasts in the presence of the cytokines, GM-CSF or IL-3, but they initiate differentiation and undergo granulopoiesis in the presence of granulocyte CSF (G-CSF). 32D cells expressing constitutively active forms of Notch1 or Notch2 proteins that signal through the CBF1 pathway maintained significantly higher numbers of viable cells and exhibited less cell death during G-CSF induction compared with controls. They also displayed enhanced entry into granulopoiesis, and inhibited postmitotic terminal differentiation. In contrast, Notch1 constructs that either lacked sequences necessary for CBF1 binding or that failed to localize to the nucleus had little effect. Elevated numbers of viable cells during G-CSF treatment were also observed in 32D cells overexpressing the basic helix-loop-helix protein (bHLH), HES1, consistent with activation of the CBF1 pathway. Taken together, our data suggest that Notch signaling enhances 32D cell survival, promotes entry into granulopoiesis, and inhibits postmitotic differentiation through a CBF1-dependent pathway.

Clinical Observations: Using a cast to manage a pressure sore

This report describes the treatment of a pressure sore on the foot of a young adult with spina bifida

A team approach to pressure relief for people with disabilities

This report describes a multidisciplinary team approach to the prevention and treatment of pressure damage in young patients with a range of physical disabilities

Getting ready for change

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Cytomegaloviral laryngitis and probable malignant lymphoma of the larynx in a patient with acquired immunodeficiency syndrome

We describe a case of cytomegaloviral laryngitis and probable primary laryngeal malignant non-Hodgkin's lymphoma in a man with acquired immunodeficiency syndrome who presented to an otolaryngology clinic with odynophagia and hoarseness. While both of these disease processes have a known association with human immunodeficiency virus infection, laryngeal presentation is extremely rare. We stress the need for thorough clinical and pathologic otolaryngologic evaluation of patients with human immunodeficiency virus infection who have upper aerodigestive complaints.

Treatment of acute severe asthma assisted by hypothermia

A 20-year-old woman in status asthmaticus who failed to respond to conventional therapy and ventilation of the lungs with 0.5-2.0% halothane, was cooled to 30 degrees C for almost 5 days as the arterial carbon dioxide tension rose above 15 kPa. Halothane was not of immediate value, contrary to other reports. A reduction in carbon dioxide production by controlled hypothermia permitted more suitable ventilation parameters, but extensive muscle weakness caused by a steroid-induced myopathy complicated weaning from respiratory support. Prospective measurement of serum creatinine phosphokinase concentration in patients given high dose corticosteroids may herald the onset of a myopathy.

Concentrations of free thyroxin and albumin in serum in severe nonthyroidal illness: assay artefacts and physiological influences

Free thyroxin (FT4) estimates by two immunoassays were compared with the concentrations of albumin in serum of apparently euthyroid subjects who either were (n = 99) or were not (n = 327) suffering from severe nonthyroidal illness (sNTI). In neither group was FT4 significantly correlated with albumin (P greater than 0.05), according to a "labeled antibody" radioassay (Amerlex-MAB). On amalgamating both groups, correlation with albumin was positive and significant (P less than 0.001). In the group with sNTI, both FT4 and albumin concentrations were decreased (mean FT4 to 77% and mean albumin to 61% of the respective reference means). For an analog radioimmunoassay (Amerlex-M), FT4 in all groups was significantly (P less than 0.001) correlated with albumin. Correlation coefficients were greater than with Amerlex-MAB for both sNTI and euthyroid groups, as well as for the joint panel. Mean FT4 in sNTI was only 44% of the reference mean. Lower radio-tracer "analog" values in sNTI are exaggerated by additional technical artefacts resulting from tracer binding to albumin.

Concentrations of free thyroxin and albumin in serum in severe nonthyroidal illness: assay artefacts and physiological influences

Free thyroxin (FT4) estimates by two immunoassays were compared with the concentrations of albumin in serum of apparently euthyroid subjects who either were (n = 99) or were not (n = 327) suffering from severe nonthyroidal illness (sNTI). In neither group was FT4 significantly correlated with albumin (P greater than 0.05), according to a "labeled antibody" radioassay (Amerlex-MAB). On amalgamating both groups, correlation with albumin was positive and significant (P less than 0.001). In the group with sNTI, both FT4 and albumin concentrations were decreased (mean FT4 to 77% and mean albumin to 61% of the respective reference means). For an analog radioimmunoassay (Amerlex-M), FT4 in all groups was significantly (P less than 0.001) correlated with albumin. Correlation coefficients were greater than with Amerlex-MAB for both sNTI and euthyroid groups, as well as for the joint panel. Mean FT4 in sNTI was only 44% of the reference mean. Lower radio-tracer "analog" values in sNTI are exaggerated by additional technical artefacts resulting from tracer binding to albumin.

Testicular ischemia and infarction following herniorrhaphy or varicocelectomy: evaluation by radionuclide imaging

The postoperative use of testicular imaging to evaluate the preservation of testicular circulation has been reported after orchiopexy, excision of a hematocele, and repair of a traumatized tunica albuginea. The authors discuss the previously unreported use of testicular imaging in patients who have undergone recent herniorrhaphy or varicocelectomy. The scan of a patient with intact testicular perfusion following herniorrhaphy is compared to the scans of two patients with absence of perfusion of a testicle five to seven days following respective herniorrhaphy and varicocelectomy surgeries.

Radiation therapy technology: manpower survey 1987

A chronic shortage of radiation therapy technologists exists in the United States. This report presents the data obtained in a 1987 survey of all radiation oncology facilities identified by the Patterns of Care master list. Of the 1,142 questionnaires mailed, 52% were returned. The survey identified 2,328 credentialed (ARRT) and 554 non-credentialed technologists employed in radiation therapy. Of this total of 2,882, 2,141 were identified as staff technologists. A total of 1,186 megavoltage units were identified, giving a ratio of 1.8 technologist/megavoltage unit. Two hundred sixty open funded positions and 230 unfunded positions for radiation therapy technologists were identified. The report compares the results of this 1987 Radiation Therapy Technology Manpower Survey with the results of the three previous surveys conducted in 1975, 1977, and 1981. Whereas this comparison demonstrates that progress has been made, current trends in allied health education are expected to have a negative impact on recruitment into radiation therapy technology. Program directors report that the number and quality of applicants to all allied health education programs is declining, and this trend in radiation therapy technology is substantiated by a drop in the number of students enrolled in programs, from 970 in 1986-87 to 777 in 1987-88. Our discussion addresses the areas of new program development, recruitment, retention, innovative programs, and overseas recruitment.

Suppression of gonadotrophin secretion does not reverse premature ovarian failure

The effect of prolonged inhibition of gonadotrophin secretion was studied in 12 women with premature ovarian failure. All the patients had plasma concentrations of follicle-stimulating hormone (FSH) greater than 20 i.u./l, and in six, primordial follicles had been seen on ovarian biopsy. Goserelin (Zoladex, ICI), a depot synthetic analogue of luteinizing hormone-releasing hormone (LHRH) was administered by three consecutive 4-weekly injections. Plasma concentrations of luteinizing hormone (LH) fell from 34 (SD 11) i.u./l to 2.4 (SD 1.9) i.u./l, and plasma concentrations of FSH fell from 106 (SD 29) i.u./l to 4.5 (SD 2.6) i.u./l 4 weeks after the first injection. Plasma concentrations of gonadotrophins returned to pretreatment values in every patient within 9 weeks of the final injection of goserelin. Regular ultrasonography during the period following the final injection failed to demonstrate the development of ovarian follicles in any patient, and plasma concentrations of oestradiol remained below 100 pmol/l. This study has failed to show that suppression of gonadotrophin secretion reverses premature ovarian failure.

Fetal inflammatory response in second trimester candidal chorioamnionitis

Candidal chorioamnionitis is an uncommon and apparently rather indolent intrauterine infection in which the fetus is able to marshal some of the immunological forces at its disposal against an easily visualized antigen impinging on lung mucosal surfaces. In a retrospective histological study of one of the largest reported series of these cases, we have encountered one each of 13, 16 and 22 weeks gestation, respectively. Of these, the youngest at 13 weeks showed no inflammatory response or positive cells on immunoperoxidase staining for immunoglobulins and proliferating Candida colonies were evident in the lungs. The 16 and 22 week cases revealed a unique giant cell response in the terminal airways and increasing numbers of cells staining positively for immunoglobulins, predominantly IgM, but with an increased proportion of IgA positive cells in the older case. Preliminary studies with a pan-T-cell antiserum on paraffin-embedded lung tissue from these cases have been encouraging with few positive cells seen in sections from the 13-week or control cases but abundant cells in the lungs of the two older infected cases. Some aspects of the relationship of these uncommonly encountered cases to the ontogeny of human immunity are discussed.