A high affinity pyruvate decarboxylase is present in cottonwood leaf veins and petioles: a second source of leaf acetaldehyde emission?

Considerable evidence indicates that acetaldehyde is released from the leaves of a variety of plants. The conventional explanation for this is that ethanol formed in the roots is transported to the leaves where it is converted to acetaldehyde by the alcohol dehydrogenase (ADH) found in the leaves. It is possible that acetaldehyde could also be formed in leaves by action of pyruvate decarboxylase (PDC), an enzyme with an uncertain metabolic role, which has been detected, but not characterized, in cottonwood leaves. We have found that leaf PDC is present in leaf veins and petioles, as well as in non-vein tissues. Veins and petioles contained measurable pyruvate concentrations in the range of 2mM. The leaf vein form of the enzyme was purified approximately 143-fold, and, at the optimum pH of 5.6, the K(m) value for pyruvate was 42 microM. This K(m) is lower than the typical millimolar range seen for PDCs from other sources. The purified leaf PDC also decarboxylates 2-ketobutyric acid (K(m)=2.2mM). We conclude that there are several possible sources of acetaldehyde production in cottonwood leaves: the well-characterized root-derived ethanol oxidation by ADH in leaves, and the decarboxylation of pyruvate by PDC in leaf veins, petioles, and other leaf tissues. Significantly, the leaf vein form of PDC with its high affinity for pyruvate, could function to shunt pyruvate carbon to the pyruvate dehydrogenase by-pass and thus protect the metabolically active vascular bundle cells from the effects of oxygen deprivation.

Meta-analysis and imputation identifies a 109 kb risk haplotype spanning TNFAIP3 associated with lupus nephritis and hematologic manifestations

TNFAIP3 encodes the ubiquitin-modifying enzyme, A20, a key regulator of inflammatory signaling pathways. We previously reported association between TNFAIP3 variants and systemic lupus erythematosus (SLE). To further localize the risk variant(s), we performed a meta-analysis using genetic data available from two Caucasian case-control datasets (1453 total cases, 3381 total control subjects) and 713 SLE trio families. The best result was found at rs5029939 (P=1.67 x 10(-14), odds ratio=2.09, 95% confidence interval 1.68-2.60). We then imputed single nucleotide polymorphisms (SNPs) from the CEU Phase II HapMap using genotypes from 431 SLE cases and 2155 control subjects. Imputation identified 11 SNPs in addition to three observed SNPs, which together, defined a 109 kb SLE risk segment surrounding TNFAIP3. When evaluating whether the rs5029939 risk allele was associated with SLE clinical manifestations, we observed that heterozygous carriers of the TNFAIP3 risk allele at rs5029939 have a twofold increased risk of developing renal or hematologic manifestations compared to homozygous non-risk subjects. In summary, our study strengthens the genetic evidence that variants in the region of TNFAIP3 influence risk for SLE, particularly in patients with renal and hematologic manifestations, and narrows the risk effect to a 109 kb DNA segment that spans the TNFAIP3 gene.

Fellow eye changes in optic neuritis correlate with the risk of multiple sclerosis

BACKGROUND

Recent studies demonstrate early diffuse central nervous system (CNS) inflammation in patients with multiple sclerosis (MS). The clinically unaffected (fellow) eye of patients with unilateral optic neuritis (ON) may reflect the status of normal-appearing white matter in the CNS, which can be assessed electrophysiologically.

OBJECTIVE

To study the relationship between electrophysiological parameters in the fellow eye of ON patients, and risk of conversion to MS.

METHODS

Forty-eight consecutive patients with acute unilateral ON were examined 12 months after ON of which 14 had MS, 19 remained high risk (HR) for MS, and 15 had low risk (LR) for MS according to McDonald's criteria. Twenty-five age-matched controls were also tested. Amplitude and latency of multifocal visual evoked potential (mfVEP) in the fellow eyes of patients at 12 months were analyzed and compared with controls.

RESULTS

Average mfVEP amplitude was 240 +/- 35, 232 +/- 36, 181 +/- 38, and 169 +/- 48 nV for controls, LR, HR, and MS groups respectively. Average mfVEP latency for controls, LR, HR, and MS patients was 139.7 +/- 5.5, 141.7 +/- 3.6, 145.9 +/- 8.9, and 152.0 +/- 9.9 ms respectively.

CONCLUSIONS

The magnitude of latency prolongation and amplitude decline 12 months after the initial episode was proportional to the risk of MS. The prognostic significance of these changes as predictors of subsequent MS should be investigated longitudinally.

Ixabepilone and lapatinib for HER2-positive advanced breast cancer: Preclinical rationale and phase I trial

2582

Trastuzumab with or without taxanes are the cytotoxic therapies of choice for advanced Her-2 positive breast cancer. Ixabepilone and lapatinib have demonstrated clinical efficacy in advanced breast cancer that is resistant to taxanes and trastuzumab. We have compared the therapeutic potential of ixabepilone, lapatinib, paclitaxel and trastuzumab, in vitro, prior to commencing a phase I clinical trial. Three different breast cancer cell lines SK-BR3, BT-474 and MCF-7 (control; non-Her-2 amplified), were seeded 96-well plates, cultured for 24 hours and different concentrations of ixabepilone or paclitaxel and trastuzumab or lapatinib were added. Experiments were performed in triplicate. A MTT viability assay was used to measure the activity of live cells after 0, 3, 24, 48 and 120 hours. The cells and vehicle control wells were averaged and normalized to 100% for comparison to the average value of the 6 replicate wells graphed over time for each cell line, drug concentration and cell density. Student-t test was used to determine the level of significance comparing the 0 hour time point in a pair-wise, pooled variance manner to each other time point. Paclitaxel + trastuzumab significantly reduced proliferation p < 0.001 at 120 hrs; Paclitaxel + lapatinib significantly reduced proliferation p < 0.001 at 120 hrs; Ixabepilone + trastuzumab significantly reduced proliferation p < 0.001 at 120 hrs; Ixabepilone + lapatinib significantly reduced proliferation p < 0.001 at 120 hrs; Dose response curves were clearly evident for all combinations. Of note proliferation was reduced earlier and at lower drug concentrations with lapatinib combinations than with trastuzumab combinations. The drugs whose efficacy was proven in MCF-7 cells were studied in detail on the xCELLigence cell analysis system. These data recapitulated the MTT data and provided in depth detail of the rate of drug action. An international multicentre phase I trial of Ixabepilone with lapatinib ± capecitabine has commenced in patients with Her-2 positive taxane and trastuzumab resistant advanced breast cancer. Toxicity has been as previously described with fatigue, arthralgias, onycholysis and rash occurring. No DLTs have occurred. RECIST responses have been confirmed in 2 of the first 3 patients enrolled.

[Table: see text]

Combination products regulation at the FDA

The US Food and Drug Administration (FDA) is responsible for protecting the public health by assuring the safety, efficacy, and security of drugs, biological products, and medical devices. As single-entity products, drugs are generally regulated by the Center for Drug Evaluation and Research (CDER), devices by the Center for Devices and Radiological Health (CDRH), and biologics by the Center for Biologics Evaluation and Research (CBER). In recent years, technological advances have led to a blurring of the historical lines of separation between the centers.

134. EPIDERMAL GROWTH FACTOR RECEPTOR/MAPK3/1 PATHWAY CROSS-TALK ENABLES GROWTH DIFFERENTIATION FACTOR 9 TO SIGNAL THROUGH SMAD2/3 IN MOUSE GRANULOSA CELLS

Oocyte-secreted growth differentiation factor 9 (GDF9) plays a critical role throughout folliculogenesis. It has been shown to control many functions of granulosa cells, including gene expression, steroidogenesis and proliferation. This study investigates the cellular requirements that allow GDF9 to act on granulosa cells. Our results showed that GDF9 (20 ng/ml)-stimulated mouse granulosa cells 3H-thymidine incorporation was inhibited by a type 1 receptor Alk4/5/7 inhibitor (SB431542, 5 μM), by an epidermal growth factor (EGF) receptor inhibitor (AG1478, 5μM) and a MEK1 inhibitor (U0126, 10 μM). Interestingly, activin A- and TGFβ-stimulated 3H-thymidine incorporation shared similar inhibitor sensitivity. Moreover, when denuded oocytes were used as the mitogenic agent, SB431542, AG1478 and U0126 all prevented the increase in 3H-thymidine incorporation. Oocyte-stimulated 3H-thymidine incorporation in secondary follicles and cumulus-oocyte complexes were also sensitive to Alk4/5/7, EGF receptor and MEK1 inhibition. Basal and EGF-stimulated levels of phopho-MAPK3/1 were inhibited by using the EGF receptor inhibitor, but were not affected by inhibition of Alk4/5/7 or by adding GDF9 in granulosa cells. Using granulosa cells transfected with a SMAD3-luciferase reporter construct, GDF9-stimulated SMAD3 response could be inhibited by Alk4/5/7, EGFR and MEK1 inhibitors. Genes involved in cumulus cells expansion (Ptx3 and Has2) were upregulated in granulosa cells by co-culturing with denuded oocytes and that upregulation was inhibited by Alk4/5/7 as well as by EGF receptor inhibition. These results suggest that TGFβ superfamily members signalling through Smad2/3 share a common requirement of EGF receptor-dependant phospho-MAPK3/1 throughout folliculogenesis. These results strongly suggest that, apart from its role in the transmission of the ovulatory LH signal within the ovarian follicle, EGF receptor pathway might serve as modulators of GDF9 action on granulosa cells. Hence the interaction between endocrine and oocyte signalling may be mediated at the level of MAPK and Smad2/3 cross-talk in granulosa cells.

A p53-CBP/p300 transcription module is required for GAP-43 expression, axon outgrowth, and regeneration

Transcription regulates axon outgrowth and regeneration. However, to date, no transcription complexes have been shown to control axon outgrowth and regeneration by regulating axon growth genes. Here, we report that the tumor suppressor p53 and its acetyltransferases CBP/p300 form a transcriptional complex that regulates the axonal growth-associated protein 43, a well-characterized pro-axon outgrowth and regeneration protein. Acetylated p53 at K372-3-82 drives axon outgrowth, GAP-43 expression, and binds specific elements on the neuronal GAP-43 promoter in a chromatin environment through CBP/p300 signaling. Importantly, in an axon regeneration model, both CBP and p53 K372-3-82 are induced following axotomy in facial motor neurons, where p53 K372-3-82 occupancy of GAP-43 promoter is enhanced as shown by in vivo chromatin immunoprecipitation. Finally, by comparing wild-type and p53 null mice, we demonstrate that the p53/GAP-43 transcriptional module is specifically switched on during axon regeneration in vivo. These data contribute to the understanding of gene regulation in axon outgrowth and may suggest new molecular targets for axon regeneration.

Multifocal VEP and OCT in optic neuritis: a topographical study of the structure-function relationship

PURPOSE

To investigate topographical relationship between amplitude of multifocal visual evoked potentials (mfVEP) and retinal nerve fibre layer (RNFL) thickness following acute optic neuritis (ON).

PATIENTS AND METHODS

Fifty patients with a clinical diagnosis of acute unilateral ON between 6 and 36 months prior to the study and 25 age-matched controls underwent mfVEP testing (Accumap V 2.1, ObjectiVision Pty Ltd, Sydney, Australia) and OCT imaging (fast RNFL protocol, Stratus, software version 3.0, Carl Zeiss Meditec, Inc., Dublin, CA). RNFL thickness and mfVEP amplitude were measured for upper, temporal and lower retinal sectors and corresponding areas of the visual field in affected eyes of ON patients and control eyes. Inter-eye asymmetry coefficients for both RNFL thickness and mfVEP amplitude were calculated for each zone, and corresponding coefficients were correlated between each other.

RESULTS

There was highly significant reduction of RNFL thickness and mean mfVEP amplitude in all three retinal sectors of the affected eye. Largest reduction of RNFL thickness was noticed in temporal sector and of mfVEP amplitude in corresponding central part of the visual field. RNFL thickness correlated highly with amplitude of the mfVEP derived from corresponding areas of the visual field in all three zones.

CONCLUSIONS

We demonstrated strong topographical associations between structural and functional measures of optic nerve integrity in patients with ON.

Demonstration of large-aperture tiled-grating compressors for high-energy, petawatt-class, chirped-pulse amplification systems

Two large-aperture tiled-grating (1.5 m) compressors, each consisting of four sets of tiled-grating assemblies, have been built for the OMEGA EP high-energy petawatt-class laser system. The techniques used for tiling individual tiled-grating assemblies and for optimizing the overall performance of a tiled-grating compressor are described. Both compressors achieved subpicosecond pulse duration without tiling-induced temporal degradation. A ray-tracing model predicted that the static wavefront of the grating tiles dominated focal-spot degradations when submicroradian tiling accuracy is achieved. The tiled-grating compressors delivered a tighter focal spot compared with subaperture grating compressors with single central tiles.

ICONE: An International Consortium of Neuro Endovascular Centres

SUMMARY

The proliferation of new endovascular devices and therapeutic strategies calls for a prudentand rational evaluation of their clinical benefit. This evaluation must be done in an effective manner and in collaboration with industry. Such research initiative requires organisation a land methodological support to survive and thrive in a competitive environment. We propose the formation of an international consortium, an academic alliance committed to the pursuit of effective neurovascular therapies. Such a consortium would be dedicated to the designand execution of basic science, device developmentand clinical trials. The Consortium is owned and operated by its members. Members are international leaders in neurointerventional research and clinical practice. The Consortium brings competency, knowledge, and expertise to industry as well as to its membership across aspectrum of research initiatives such as: expedited review of clinical trials, protocol development, surveys and systematic reviews; laboratory expertise and support for research design and grant applications to public agencies. Once objectives and protocols are approved, the Consortium provides a stable network of centers capable of timely realization of clinical trials or pre clinical investigations in an optimal environment. The Consortium is a non-profit organization. The potential revenue generated from clientsponsored financial agreements will be redirected to the academic and research objectives of the organization. The Consortium wishes to work inconcert with industry, to support emerging trends in neurovascular therapeutic development. The Consortium is a realistic endeavour optimally structured to promote excellence through scientific appraisal of our treatments, and to accelerate technical progress while maximizing patients' safety and welfare.