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result(s) for
"Schneider, Meike"
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Dynamic formation of a solid-liquid electrolyte interphase and its consequences for hybrid-battery concepts
2016
The discharging and charging of batteries require ion transfer across phase boundaries. In conventional lithium-ion batteries, Li
+
ions have to cross the liquid electrolyte and only need to pass the electrode interfaces. Future high-energy batteries may need to work as hybrids, and so serially combine a liquid electrolyte and a solid electrolyte to suppress unwanted redox shuttles. This adds new interfaces that might significantly decrease the cycling-rate capability. Here we show that the interface between a typical fast-ion-conducting solid electrolyte and a conventional liquid electrolyte is chemically unstable and forms a resistive solid-liquid electrolyte interphase (SLEI). Insights into the kinetics of this new type of interphase are obtained by impedance studies of a two-chamber cell. The chemistry of the SLEI, its growth with time and the influence of water impurities are examined by state-of-the-art surface analysis and depth profiling.
Li
+
-selective solid electrolytes may enable next-generation battery systems, such as Li–S and Li–O
2
. Now, in an exemplar system, it is shown that a resistive interphase forms at the interface between solid and liquid electrolytes, termed the solid-liquid electrolyte interphase (SLEI). An
in situ
study of this undesirable effect is supported by state-of-the-art surface analysis.
Journal Article
Characterization of colon cancer cells: a functional approach characterizing CD133 as a potential stem cell marker
2012
Background
Isolation and characterization of tumourigenic colon cancer initiating cells may help to develop novel diagnostic and therapeutic procedures.
Methods
We characterized a panel of fourteen human colon carcinoma cell lines and their corresponding xenografts for the surface expression of potential stem cell markers CD133, CD24, CD44, CDCP1 and CXCR4. In five cell lines and nine xenografts, mRNA expression of these markers was determined. Tumour growth behaviour of CD133+, CD133- and unsorted SW620 cells was evaluated
in vivo
.
Results
All five putative stem cell markers showed distinct expression patterns in the tumours examined. Two patient-derived cell lines highly expressed CD133 (> 85% of positive cells) and three other cell lines had an expression level of about 50% whereas in long-term culture based models CD133 expression ranged only from 0 to 20%. In 8/14 cell lines, more than 80% of the cells were positive for CD24 and 11/14 were over 70% positive for CD44. 10/14 cell lines expressed CDCP1 on ≥ 83% of cells. CXCR4 expression was determined solely on 94 L and SW480.
Analyses of the corresponding xenografts revealed a significant reduction of cell numbers expressing the investigated surface markers and showed single cell fractions expressing up to three markers simultaneously.
Statistical analysis revealed that the CXCR4 mRNA level correlates negatively with the protein expression of CD133, CD44, CD24 and CDCP1 in cell lines and xenografts.
A lower differentiation grade of donor material correlated with a higher CDCP1 mRNA expression level in the respective tumour model.
In vivo
growth behaviour studies of SW620 revealed significantly higher take rates and shorter doubling times in the tumour growth of CD133 positive subclones in comparison to the unsorted cell line or CD133 negative subclones.
Conclusions
Our data revealed correlations in the expression of surface markers CD44 and CD24 as well as CD44 and CDCP1 and strongly suggest that CD133 is a stem cell marker within our colon carcinoma panel. Further studies will elucidate its role as a potential therapeutic target.
Journal Article
T-Cell Heterogeneity in Baseline Tumor Samples: Implications for Early Clinical Trial Design and Analysis
2022
In early stage clinical trials, changes to levels of tumor infiltrating lymphocytes (TILs) in the tumor microenvironment (TME) are critical biomarkers of the mechanism of action of novel immunotherapies. However, baseline heterogeneity of tumor samples, both between and within patients, and the resultant impact on the validity of clinical trial data is not well defined. Here we identify and quantify the impact of baseline variables on the heterogeneity of FoxP3+ and proliferating CD8+ T-cells levels (MKi67+CD8A+) in the TME both between and within patients for the purpose of informing clinical trial design and analysis.
We compared levels of FoxP3+ and MKi67+CD8+ cell densities (counts/mm
) from >1000 baseline tumor samples from clinical trials and commercially available sources. Using multivariate hierarchical regression techniques, we investigated whether inter-person heterogeneity of activated or regulatory T-cells could be attributed to baseline characteristics including demographics, indication, lesion type, tissue of excision, biopsy method, prior cancer treatment, and tissue type i.e., \"fresh\" or \"archival\" status. We also sought to characterize within-patient heterogeneity by lesion type and tissue type.
Prior cancer treatment with hormone therapy or chemotherapy that induces immunogenic cell death may alter the TME. Archival tissue is an unreliable substitute for fresh tissue for determining baseline TIL levels. Baseline and on treatment biopsies should be matched by lesion type to avoid bias.
Journal Article
Does preoperative platelet count and thrombocytosis play a prognostic role in patients undergoing nephrectomy for renal cell carcinoma? Results of a comprehensive retrospective series
by
Otto, Wolfgang
,
Zigeuner, Richard
,
Ficarra, Vincenzo
in
Aged
,
Carcinoma, Renal Cell - diagnosis
,
Carcinoma, Renal Cell - mortality
2013
Purpose
To evaluate the still controversially discussed prognostic role of preoperative platelet level (PPL) and thrombocytosis (TC) in patients who undergo surgery for renal cell carcinoma (RCC) based on the largest patient series reported to date.
Methods
A total of 3,139 patients, who underwent radical or nephron-sparing nephrectomy at four centres, were subdivided based on a threshold for preoperative platelets of 400 × 10
9
cells/L. Univariate and multivariable Cox regression analyses were applied to determine the prognostic influence of PPL and TC on cancer-specific survival (CSS) for patients with localized and metastatic disease at presentation.
Results
Group 1 (PPL ≤ 400/nl) and Group 2 (PPL > 400/nl) included 2,862 (91 %) and 277 patients (9 %), respectively. With a median follow-up (FU) of 69.5 months (IQR: 35–105), CSS of all patients after 5 years was 84.6 % in Group 1 versus 53.4 % in Group 2 (
p
< 0.001). At multivariable analysis, TC (HR:1.337;
p
= 0.007) and continuous PPL (HR:1.001;
p
= 0.002) independently predicted a decreased survival. However, integration of these parameters into multivariable models for the entire study group and for patients with localized tumours did only result in marginal improvement of the model quality (0.66 and 1.04 %, respectively). Interestingly, neither TC (
p
= 0.257) nor PPL (
p
= 0.132) significantly influenced survival in M1 patients.
Conclusions
Preoperative TC turned out an independent predictor for decreased CSS in patients undergoing surgery for localized RCC. However, significant improvement of multivariable models comprising standard clinical and pathological parameters by the inclusion of TC is not achieved. In metastatic disease, TC did not reveal an independent influence on CSS.
Journal Article
Glutaminase and poly(ADP-ribose) polymerase inhibitors suppress pyrimidine synthesis and VHL-deficient renal cancers
by
Stemmer-Rachamimov, Anat
,
Iliopoulos, Othon
,
Okazaki, Arimichi
in
1-Phosphatidylinositol 3-kinase
,
Acetylcysteine
,
Acute myeloid leukemia
2017
Many cancer-associated mutations that deregulate cellular metabolic responses to hypoxia also reprogram carbon metabolism to promote utilization of glutamine. In renal cell carcinoma (RCC), cells deficient in the von Hippel-Lindau (VHL) tumor suppressor gene use glutamine to generate citrate and lipids through reductive carboxylation (RC) of α-ketoglutarate (αKG). Glutamine can also generate aspartate, the carbon source for pyrimidine biosynthesis, and glutathione for redox balance. Here we have shown that VHL-/- RCC cells rely on RC-derived aspartate to maintain de novo pyrimidine biosynthesis. Glutaminase 1 (GLS1) inhibitors depleted pyrimidines and increased ROS in VHL-/- cells but not in VHL+/+ cells, which utilized glucose oxidation for glutamate and aspartate production. GLS1 inhibitor-induced nucleoside depletion and ROS enhancement led to DNA replication stress and activation of an intra-S phase checkpoint, and suppressed the growth of VHL-/- RCC cells. These effects were rescued by administration of glutamate, αKG, or nucleobases with N-acetylcysteine. Further, we observed that the poly(ADP-ribose) polymerase (PARP) inhibitor olaparib synergizes with GLS1 inhibitors to suppress the growth of VHL-/- cells in vitro and in vivo. This work describes a mechanism that explains the sensitivity of RCC tumor growth to GLS1 inhibitors and supports the development of therapeutic strategies for targeting VHL-deficient RCC.
Journal Article
Early onset renal cell carcinoma in an adolescent girl with germline FLCN exon 5 deletion
2018
Birt-Hogg-Dube (BHD) disease is an autosomal dominant cancer syndrome characterized by benign skin tumors, renal cancer and spontaneous pneumothorax and is caused by mutations in the Folliculin (FLCN) gene. Benign skin tumors and pneumothorax occur in the majority of patients affected by BHD syndrome, but only 30–45% of them develop renal cell carcinoma (RCC) with a median age of diagnosis at 48. The earliest onset of RCC in a BHD patient has been reported at age 20. Here we report a case of a 14 year-old patient with germline FLCN mutation leading to an early-onset bulky RCC that could not be classified strictly according to existing histological types. Germline genetic testing revealed a deletion at FLCN exon 5. The father of the patient was identified as the asymptomatic carrier. We report the youngest patient with BHD-related RCC. This early onset presentation supports genetic testing of at-risk patients and initiation of imaging surveillance for RCC in early adolescence. In addition, future studies are necessary to understand the determinants of reduced penetrance in BHD disease.
Journal Article
Multimedia Support for Improving Preoperative Patient Education: A Randomized Controlled Trial Using the Example of Radical Prostatectomy
by
Ihrig, Andreas
,
Huber, Johannes
,
Stredele, Regina J.F.
in
Aged
,
Anxiety - psychology
,
Chi-Square Distribution
2013
Background
Growing evidence supports the use of multimedia presentations for informing patients. Therefore, we supported preoperative education by adding a multimedia tool and examined the effects in a randomized controlled trial.
Methods
We randomized German-speaking patients scheduled for radical prostatectomy at our center to receive either a multimedia-supported (MME) or a standard education (SE). Outcomes were measured in a structured interview. Primary outcome was patient satisfaction. In addition, we applied validated instruments to determine anxiety and measures of decision-making. Results were given by mean and standard deviation. For comparison of groups we used
t
test and chi-square test. For an explorative analysis we applied multivariate logistic regression.
Results
We randomized 203 patients to receive MME (
n
= 102) or SE (
n
= 101). Complete satisfaction with preoperative education was more frequent in the MME group (69 vs 52 %,
p
= .016) and patients after MME reported more questions (5.7 vs 4.2,
p
= .018). There was no difference concerning the duration of talks and the number of recalled risks. However, perceived knowledge was higher after MME (1.3 vs 1.6,
p
= .037). Anxiety and measures of decision-making were comparable. Patients judged the multimedia tool very positive, and 74 % of the MME group thought that their preoperative education had been superior to SE.
Conclusions
Multimedia support should be considered worthwhile for improving the informed consent process before surgery (
www.germanctr.de
; DRKS00000096).
Journal Article
Glutaminase and poly polymerase inhibitors suppress pyrimidine synthesis and VHL-deficient renal cancers
by
Stemmer-Rachamimov, Anat
,
Iliopoulos, Othon
,
Okazaki, Arimichi
in
Adenosine diphosphate
,
Development and progression
,
Gene mutation
2017
Many cancer-associated mutations that deregulate cellular metabolic responses to hypoxia also reprogram carbon metabolism to promote utilization of glutamine. In renal cell carcinoma (RCC), cells deficient in the von Hippel-Lindau (VHL) tumor suppressor gene use glutamine to generate citrate and lipids through reductive carboxylation (RC) of [alpha]-ketoglutarate ([alpha]/KG). Glutamine can also generate aspartate, the carbon source for pyrimidine biosynthesis, and glutathione for redox balance. Here we have shown that [VHL.sup.-/-] RCC cells rely on RC-derived aspartate to maintain de novo pyrimidine biosynthesis. Glutaminase 1 (GLS1) inhibitors depleted pyrimidines and increased ROS in [VHL.sup.-/-] cells but not in [VHL.sup.+/+] cells, which utilized glucose oxidation for glutamate and aspartate production. GLS1 inhibitor-induced nucleoside depletion and ROS enhancement led to DNA replication stress and activation of an intra-S phase checkpoint, and suppressed the growth of [VHL.sup.-/-] RCC cells. These effects were rescued by administration of glutamate, [alpha]KG, or nucleobases with N-acetylcysteine. Further, we observed that the poly(ADP-ribose) polymerase (PARP) inhibitor olaparib synergizes with GLS1 inhibitors to suppress the growth of [VHL.sup.-/-] cells in vitro and in vivo. This work describes a mechanism that explains the sensitivity of RCC tumor growth to GLS1 inhibitors and supports the development of therapeutic strategies for targeting VHL-deficient RCC.
Journal Article
Docetaxel-rechallenge in castration-resistant prostate cancer: defining clinical factors for successful treatment response and improvement in overall survival
2018
PurposeThe purpose of the study was to define clinical factors for successful treatment response and re-exposure to docetaxel in metastatic castration-resistant prostate cancer (mCRPC).MethodsAn mCRPC database of patients receiving first-line docetaxel and rechallenge courses was established. Several clinical factors were evaluated for prediction of treatment response. Multivariate cox-regression analysis was used to define pre-treatment and treatment factors for survival.ResultsBetween 2005 and 2013, 94 patients with mCRPC were treated with docetaxel. Full data set and follow-up were available for 62 patients. Median follow-up was 84 m [interquartile range (IQR) 64–104 m]. Median biochemical progression-free survival (bPFS) and overall survival under docetaxel were 9 m (IQR 5–16 m) and 20 m (IQR 16–26 m), respectively. Partial PSA-response at first docetaxel-sequence (n = 62), rechallenge (n = 32), and third-sequence (n = 22) docetaxel was 48.4%, 31.6%, and 34.8%, respectively. Time from start of primary androgen deprivation to CRPC > 47 m was the only independent pre-treatment parameter to predict improved overall survival (Hazard Ratio 0.48, p = 0.015). Interestingly, there was a strong trend for improved overall survival in patients with high Gleason Score (Hazard Ratio 0.58; p = 0.08). Partial PSA-response at docetaxel-rechallenge (Hazard Ratio 0.31; p = 0.008) and treatment-free interval > 3 m (Hazard Ratio 3.49; p = 0.014) were the only independent predictive factors under taxane treatment for overall survival.ConclusionDespite novel hormonal drugs, docetaxel still plays an important role in the treatment of mCRPC. Patients with partial-PSA-response at rechallenge or a treatment-free interval > 3 m benefit most from docetaxel re-exposure.
Journal Article
Glutaminase and poly
by
Stemmer-Rachamimov, Anat
,
Iliopoulos, Othon
,
Okazaki, Arimichi
in
Adenosine diphosphate
,
Development and progression
,
Gene mutation
2017
Many cancer-associated mutations that deregulate cellular metabolic responses to hypoxia also reprogram carbon metabolism to promote utilization of glutamine. In renal cell carcinoma (RCC), cells deficient in the von Hippel-Lindau (VHL) tumor suppressor gene use glutamine to generate citrate and lipids through reductive carboxylation (RC) of [alpha]-ketoglutarate ([alpha]/KG). Glutamine can also generate aspartate, the carbon source for pyrimidine biosynthesis, and glutathione for redox balance. Here we have shown that [VHL.sup.-/-] RCC cells rely on RC-derived aspartate to maintain de novo pyrimidine biosynthesis. Glutaminase 1 (GLS1) inhibitors depleted pyrimidines and increased ROS in [VHL.sup.-/-] cells but not in [VHL.sup.+/+] cells, which utilized glucose oxidation for glutamate and aspartate production. GLS1 inhibitor-induced nucleoside depletion and ROS enhancement led to DNA replication stress and activation of an intra-S phase checkpoint, and suppressed the growth of [VHL.sup.-/-] RCC cells. These effects were rescued by administration of glutamate, [alpha]KG, or nucleobases with N-acetylcysteine. Further, we observed that the poly(ADP-ribose) polymerase (PARP) inhibitor olaparib synergizes with GLS1 inhibitors to suppress the growth of [VHL.sup.-/-] cells in vitro and in vivo. This work describes a mechanism that explains the sensitivity of RCC tumor growth to GLS1 inhibitors and supports the development of therapeutic strategies for targeting VHL-deficient RCC.
Journal Article