Widely tunable short-infrared thulium and holmium doped fluorozirconate waveguide chip lasers

We report widely tunable (≈ 260 nm) Tm(3+) and Ho(3+) doped fluorozirconate (ZBLAN) glass waveguide extended cavity lasers with close to diffraction limited beam quality (M(2) ≈ 1.3). The waveguides are based on ultrafast laser inscribed depressed claddings. A Ti:sapphire laser pumped Tm(3+)-doped chip laser continuously tunes from 1725 nm to 1975 nm, and a Tm(3+)-sensitized Tm(3+):Ho(3+) chip laser displays tuning across both ions evidenced by a red enhanced tuning range of 1810 to 2053 nm. We also demonstrate a compact 790 nm diode laser pumped Tm(3+)-doped chip laser which tunes from 1750 nm to 1998 nm at a 14% incident slope efficiency, and a beam quality of M(2) ≈ 1.2 for a large mode-area waveguide with 70 µm core diameter.

[Batch release of immunoglobulin and monoclonal antibody products]

The Paul-Ehrlich Institute (PEI) is an independent institution of the Federal Republic of Germany responsible for performing official experimental batch testing of sera. The institute decides about the release of each batch and performs experimental research in the field. The experimental quality control ensures the potency of the product and also the absence of harmful impurities. For release of an immunoglobulin batch the marketing authorization holder has to submit the documentation of the manufacture and the results of quality control measures together with samples of the batch to the PEI. Experimental testing is performed according to the approved specifications regarding the efficacy and safety. Since implementation of the 15th German drug law amendment, the source of antibody is not defined anymore. According to § 32 German drug law, all batches of sera need to be released by an official control laboratory. Sera are medicinal products, which contain antibodies, antibody fragments or fusion proteins with a functional antibody portion. Therefore, all batches of monoclonal antibodies and derivatives must also be released by the PEI and the marketing authorization holder has to submit a batch release application. Under certain circumstances a waiver for certain products can be issued with regard to batch release. The conditions for such a waiver apply to the majority of monoclonal antibodies.

Analysis of risk factors for long-term glaucomatous damage development

PURPOSE

The aim of this study was to analyze predictors of long-term glaucoma progression.

PATIENTS AND METHODS

We followed 17 primary open angle glaucoma patients (POAG) and 25 ocular hypertensives (OHT) over three years, with regular follow-up examinations of both eyes every 6 months. Glaucoma damage was quantified by optical coherence tomography (retinal nerve fiber layer - OCT RNFL) and by perimetry. Corneal and hand temperature (infrared thermometer), corneal hysteresis, pachymetry and ocular pulse amplitude (OPA) readings were taken at baseline, and applanatory intraocular pressure and retinal vessel analysis recordings were made at baseline and follow-up visits. Forward-stepwise multiple regression analysis was performed.

RESULTS

With OCT-RNFL progression as the dependent variable, the model selected initial diagnosis (OHT less probable of progressing), baseline RNFL thickness, retinal arterial and venous diameter and arterial flicker response as significant damage predictors. For visual field damage progression, these were: corneal temperature, OPA, initial diagnosis and venous flicker response (all p<0.05).

CONCLUSION

Initial damage and vascular factors are strong predictors of future glaucoma progression.

Effects of grazer presence on genetic structure of a phenotypically diverse diatom population

Studies of predator-prey systems in both aquatic and terrestrial environments have shown that grazers structure the intraspecific diversity of prey species, given that the prey populations are phenotypically variable. Populations of phytoplankton have traditionally considered comprising only low intraspecific variation, hence selective grazing as a potentially structuring factor of both genetic and phenotypic diversity has not been comprehensively studied. In this study, we compared strain specific growth rates, production of polyunsaturated aldehydes, and chain length of the marine diatom Skeletonema marinoi in both grazer and non-grazer conditions by conducting monoclonal experiments. Additionally, a mesocosm experiment was performed with multiclonal experimental S. marinoi populations exposed to grazers at different levels of copepod concentration to test effects of grazer presence on diatom diversity in close to natural conditions. Our results show that distinct genotypes of a geographically restricted population exhibit variable phenotypic traits relevant to grazing interactions such as chain length and growth rates. Grazer presence affected clonal richness and evenness of multiclonal Skeletonema populations in the mesocosms, likely in conjunction with intrinsic interactions among the diatom strains. Only the production of polyunsaturated aldehydes was not affected by grazer presence. Our findings suggest that grazing can be an important factor structuring diatom population diversity in the sea and emphasize the importance of considering clonal differences when characterizing species and their role in nature.

Abstract PL02-04: IDH mutations and tumorigenicity

Mutations in the isocitrate dehydrogenase 1 (IDH1) and 2 (IDH2) genes are present in ∼20% of acute myeloid leukemia, and cause a neomorphic enzyme activity that results in the production of 2-hydroxyglutarate (2HG). Mutational and epigenetic profiling of a large patient cohort of acute myeloid leukemia (AML) has revealed that IDH1/2-mutant AMLs display global DNA hypermethylation and impaired hematopoietic differentiation.

To further investigate the intrinsic effect of 2HG on hematopoietic proliferation and differentiation, we transfected an erythroleukemia cell line (TF-1) with either IDH1 or IDH2 mutant alleles. These cells overexpress the mutant enzyme, have high levels of 2HG, and exhibit GM-CSF independent growth. Consistent with clinical observations, overexpression of the IDH mutant proteins led to hypermethylation of both histones and DNA. These results suggest that mutations in IDH1/2 could lead to epigenetic rewiring of cells that could facilitate the gain of function phenotype. We are currently studying the global and specific effects of IDH1/2 mutant overexpression to gain a broader understanding of the biological consequence of the IDH1/2 gain of function mutations.

We have also generated mutation selective molecules that are capable of inhibiting IDHm enzymes. Upon compound treatment in vitro, we are able to reverse hypermethylation of both histones and DNA and induce cellular differentiation in IDHm cell lines and primary human IDHm AML patient samples(1, 2). These data suggest that an inhibitor of IDH1/2 mutations could correct the altered gene expression patterns seen in IDH1/2 mutant AML tumors leading to a profound effect on hematopoietic differentiation, proliferation and tumor growth.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):PL02-04.

Citation Format: F. Wang, J. Travins, B. DeLaBarre, V. Penard-Lacronique, S. Schalm, E. Hansen, K. Straley, A. Kernytsky, W. Liu, C. Gliser, H. Yang, S. Gross, E. Artin, V Saada, E. Mylonas, C. Quivoron, J. Popovici-Muller, J. O. Saunders, F. G. Salituro, S. Yan, S. Murray, W. Wei, Y. Gao, L. Dang, M. Dorsch, S. Agresta, D. P. Schenkein, S. A. Biller, S. M. Su, S. de Botton, Katharine E. Yen. IDH mutations and tumorigenicity. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr PL02-04.

Abstract C60: Vitamin C inhibits the survival and growth of colorectal cancer cells with KRAS or BRAF mutations

Although more than half of colorectal cancer patients have either KRAS or BRAF mutations, targeted therapies for these subgroups of cancer patients are lacking. We previously showed that isogenic human colorectal cancer cell (CRC) lines harboring a KRAS or BRAF mutation up-regulate the expression of glucose transporter 1 (GLUT1), and increase glucose uptake and glycolysis. In this study, we go on to show that KRAS or BRAF mutant cells exhibit a significant increase in the uptake of vitamin C, mainly in its oxidized form, dehydroascorbic acid (DHA), relative to their wild-type counterparts through GLUT1. Notably, CRCs did not uptake vitamin C in its reduced form, possibly due to the fact that its known transporters, sodium vitamin C cotransporters (SVCTs) were generally not present in CRCs. Deletion of GLUT1 in mutant cells, overexpression of GLUT1 in wild-type cells and competition assays between glucose and DHA confirmed that GLUT1 is both necessary and sufficient for the uptake of vitamin C in CRCs. Both mutant and wild-type cells were able to grow in low glucose (1-2 mM) at a similar rate. In the same condition, we found vitamin C to be selectively toxic to KRAS and BRAF mutant cells, causing them to undergo apoptosis. In contrast, in high glucose levels (&gt;10 mM), a similar concentration of vitamin C had no effect on the survival and growth of mutant cells. In addition, vitamin C significantly inhibited the growth of cancer cells with KRAS or BRAF mutations in vivo xenografts models. To find the mechanism by which vitamin C induces cell death in KRAS or BRAF mutant cells, we performed targeted metabolomics using LC/MS. Both unlabeled total metabolite analysis and flux analysis with C13-Glucose isotope strongly suggested that vitamin C re-routes glucose usage from aerobic glycolysis and non-oxidative pentose phosphate pathway (PPP) to the oxidative PPP to compensate for the lower levels of NADPH which was rapidly consumed to reduce GSSH to GSH. Having taken up exclusively DHA, the oxidized state of vitamin C, the mutant cells immediately use GSH to reduce Vitamin C, resulting in the accumulation of GSSH. Shunting glucose to the oxidative PPP reduces aerobic glycolysis, lowering ATP levels, and decreases glucose anabolism, disfavoring the synthesis of nucleic acids, lipid and amino acids, all needed for the survival and growth of mutant cells. Surprisingly the level of reactive oxidative stress (ROS) was largely unchanged following vitamin C treatment possibly because increased levels of vitamin C served as an anti-oxidant in mutant cells. There are currently more than three clinical trials phase I/II examining the effect of high dose vitamin C via intravenous administration in patients against lymphoma or solid cancers including CRCs. Our findings will provide proof of concept that KRAS or BRAF mutations in CRC can be predictive biomarkers for vitamin C therapy.

Citation Format: Jihye Yun, Adam Kavalier, Jatin Roper, Steve Gross, Carlo Rago, Nickolas Papadopoulos, Bert Vogelstein, Lewis Cantley. Vitamin C inhibits the survival and growth of colorectal cancer cells with KRAS or BRAF mutations. [abstract]. In: Proceedings of the Third AACR International Conference on Frontiers in Basic Cancer Research; Sep 18-22, 2013; National Harbor, MD. Philadelphia (PA): AACR; Cancer Res 2013;73(19 Suppl):Abstract nr C60.

Versatile large-mode-area femtosecond laser-written Tm:ZBLAN glass chip lasers

We report performance characteristics of a thulium doped ZBLAN waveguide laser that supports the largest fundamental modes reported in a rare-earth doped planar waveguide laser (to the best of our knowledge). The high mode quality of waveguides up to 45 um diameter (~1075 μm(2) mode-field area) is validated by a measured beam quality of M(2)~1.1 ± 0.1. Benefits of these large mode-areas are demonstrated by achieving 1.9 kW peak-power output Q-switched pulses. The 1.89 μm free-running cw laser produces 205 mW and achieves a 67% internal slope efficiency corresponding to a quantum efficiency of 161%. The 9 mm long planar chip developed for concept demonstration is rapidly fabricated by single-step optical processing, contains 15 depressed-cladding waveguides, and can operate in semi-monolithic or external cavity laser configurations.

Initial white blood cell count is an independent risk factor for survival in patients with dilated cardiomyopathy

BACKGROUND

The impact of white blood cell count (WBCc) on the outcome of patients with non-ischemic left ventricular (LV) dysfunction is unknown. In the present study we investigated the influence of WBCc on mortality and cardiac inflammation in patients with reduced LV systolic function in the absence of ischemic or valvular etiology.

METHODS AND RESULTS

We included 381 patients with reduced left ventricular (LV) ejection fraction (LVEF ≤ 45%) quantified by two-dimensional echocardiography. Coronary artery disease and valvular diseases were excluded by angiography and echo, respectively, in all patients. WBCc was quantified routinely upon first hospital admission. In 291 patients, endomyocardial biopsies from the right ventricle were performed upon first hospital admission for assessment of cardiac inflammation. Follow-up was up to 5.5 years (median 2.93 [1.7;4.0]). Information on vital status of patients was obtained from official resident data files. WBCc >11 Gpt/l was associated with significantly increased mortality in patients with severe LV dilation (end-diastolic diameter (LVEDD) >70 mm quantified by echocardiography) in comparison to patients showing WBCc ≤ 11 Gpt/l (41.7% vs 13.6%, p=0.02). Multivariable Cox regression analysis showed that WBCc predicts mortality independently of other cardiovascular risk factors and LVEF (hazard ratio 1.14; p=0.04). Doses of heart failure medication did not differ significantly in patients with LVEDD >70 mm and WBCc >11 Gpt/l when compared to LVEDD >70 mm and WBCc ≤ 11 Gpt/l (percent of maximum doses: ß-blockers p=0.51, ACE inhibitors p=0.56, AT1 antagonists p=0.77, aldosterone antagonists p=0.35). WBCc including its subpopulations (monocytes, lymphocytes and granulocytes) did not show a significant correlation with cardiac amounts of CD3(+)-lymphocytes (r=0.02, p=0.78) or CD68(+)-macrophages (r=1.0, p=0.09) (n=291).

CONCLUSION

WBCc at first hospital admission predicts long term-mortality in patients with dilated cardiomyopathy independently of cardiovascular risk factors.