A Homozygous PPP1R21 Splice Variant Associated with Severe Developmental Delay, Absence of Speech, and Muscle Weakness Leads to Activated Proteasome Function

PPP1R21 acts as a co-factor for protein phosphatase 1 (PP1), an important serine/threonine phosphatase known to be essential for cell division, control of glycogen metabolism, protein synthesis, and muscle contractility. Bi-allelic pathogenic variants in PPP1R21 were linked to a neurodevelopmental disorder with hypotonia, facial dysmorphism, and brain abnormalities (NEDHFBA) with pediatric onset. Functional studies unraveled impaired vesicular transport as being part of PPP1R21-related pathomechanism. To decipher further the pathophysiological processes leading to the clinical manifestation of NEDHFBA, we investigated the proteomic signature of fibroblasts derived from the first NEDHFBA patient harboring a splice-site mutation in PPP1R21 and presenting with a milder phenotype. Proteomic findings and further functional studies demonstrate a profound activation of the ubiquitin-proteasome system with presence of protein aggregates and impact on cellular fitness and moreover suggest a cross-link between activation of the proteolytic system and cytoskeletal architecture (including filopodia) as exemplified on paradigmatic proteins including actin, thus extending the pathophysiological spectrum of the disease. In addition, the proteomic signature of PPP1R21-mutant fibroblasts displayed a dysregulation of a variety of proteins of neurological relevance. This includes increase proteins which might act toward antagonization of cellular stress burden in terms of pro-survival, a molecular finding which might accord with the presentation of a milder phenotype of our NEDHFBA patient.

Identification of a novel homozygous SCO2 variant in siblings with early-onset axonal Charcot-Marie-Tooth disease

The synthesis of cytochrome c oxidase 2 (SCO2) gene encodes for a mitochondrial located metallochaperone essential for the synthesis of the cytochrome c oxidase (COX) subunit 2. Recessive mutations in SCO2 have been reported in several cases with fatal infantile cardioencephalomyopathy with COX deficiency and in only four cases with axonal neuropathy. Here, we identified a homozygous pathogenic variant (c.361G>C; p.(Gly121Arg)) in SCO2 in two brothers with isolated axonal motor neuropathy. To address pathogenicity of the amino acid substitution, biochemical studies were performed and revealed increased level of the mutant SCO2-protein and a dysregulation of COX subunits in leukocytes and moreover unraveled decrease of proteins involved in the manifestation of neuropathies. Hence, our combined data strengthen the concept of SCO2 being causative for a very rare form of axonal neuropathy, expand its molecular genetic spectrum and provide first biochemical insights into the underlying pathophysiology. This article is protected by copyright. All rights reserved.

Muscular and Molecular Pathology Associated with SPATA5 Deficiency in a Child with EHLMRS

Mutations in the SPATA5 gene are associated with epilepsy, hearing loss and mental retardation syndrome (EHLMRS). While SPATA5 is ubiquitously expressed and is attributed a role within mitochondrial morphogenesis during spermatogenesis, there is only limited knowledge about the associated muscular and molecular pathology. This study reports on a comprehensive workup of muscular pathology, including proteomic profiling and microscopic studies, performed on an 8-year-old girl with typical clinical presentation of EHLMRS, where exome analysis revealed two clinically relevant, compound-heterozygous variants in SPATA5. Proteomic profiling of a quadriceps biopsy showed the dysregulation of 82 proteins, out of which 15 were localized in the mitochondrion, while 19 were associated with diseases presenting with phenotypical overlap to EHLMRS. Histological staining of our patient’s muscle biopsy hints towards mitochondrial pathology, while the identification of dysregulated proteins attested to the vulnerability of the cell beyond the mitochondria. Through our study we provide insights into the molecular etiology of EHLMRS and provide further evidence for a muscle pathology associated with SPATA5 deficiency, including a pathological histochemical pattern accompanied by dysregulated protein expression.

Abstract P6-18-08: Everolimus + exemestane for HR+ advanced breast cancer in routine clinical practice- Final results from the non-interventional trial, BRAWO

Background: In the pivotal BOLERO-2 trial, everolimus (EVE) + exemestane (EXE) more than doubled the median progression-free survival (PFS) vs EXE alone in hormone receptor positive (HR+), human epidermal growth factor-receptor 2-negative (HER2-) advanced breast cancer (ABC) recurring/progressing on/after prior non-steroidal aromatase inhibitors (NSAIs). BRAWO is a German non-interventional study conducted in patients (pts) with HR+, HER2–ABC receiving EVE + EXE, according to Summary of Product Characteristics (SmPC), in routine clinical practice. Here we report the final PFS and safety results.

Methods: This multicenter study documented 2100 pts between October 2012 and December 2017 across 341 sites in Germany. Postmenopausal women with HR+, HER2– ABC with recurrence or progression after a NSAI were included. Primary observation parameters included the evaluation of the effectiveness of EVE + EXE used in routine care for the entire pt group.

Results: In the final analysis, out of the 2100 documented pts, 2074 were included in the full analysis set. The median time since the primary diagnosis was 7.1 years and the median time from first sign of relapse (local recurrence or distant metastases) was 2.1 years. At baseline, 54.1% of pts presented with visceral metastases and 50.1% had an ECOG performance status of 0. Approximately, 63% of pts started with EVE 10 mg (median duration of exposure: 5.1 months; 95% CI, 4.6-5.4), while 34.1% started with EVE 5 mg (median duration of exposure: 4.6 months; 95% CI, 4.1-5.2).

The distribution of treatment lines was as follows: first line, 28.7% (n=595); second line, 31.9% (n=662); third line, 18.1% (n=376); fourth line, 10.7% (n=221) and, fifth line and later, 10.6% (n=220). Treatment was discontinued by 55.7% of pts (n=1170) due to progressive disease and 26% of pts (n=546) due to adverse events. The Kaplan-Meier estimate of the median PFS was 6.6 months (95% CI, 6.2-7.0). The best overall responses, based on clinical routine, were complete response, 0.8% (n=17), partial response, 7.4% (n=150), and stable disease, 41.3% (n=842). The general safety profile was consistent with the previously reported safety findings. The most common adverse events were stomatitis (any grade: 42.6%, grade 3: 3.8%, grade 4: <0.1%) and fatigue (any grade: 19.8%, grade 3: 1.5%).

Conclusions: Data from BRAWO support EVE + EXE as a suitable treatment option with a reasonable safety profile for HR+, HER2− ABC recurring or progressing on/after prior NSAIs.

Citation Format: Lüftner D, Schuetz F, Schneeweiss A, Grischke E-M, Bloch W, Decker T, Uleer C, Salat C, Förster F, Schmidt M, Mundhenke C, Tesch H, Jackisch C, Fischer T, Guderian G, Hanson S, Fasching P. Everolimus + exemestane for HR+ advanced breast cancer in routine clinical practice- Final results from the non-interventional trial, BRAWO [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-18-08.

Timing resolution studies of the optical part of the AFP Time-of-flight detector

We present results of the timing performance studies of the optical part and front-end electronics of the time-of-flight subdetector prototype for the ATLAS Forward Proton (AFP) detector obtained during the test campaigns at the CERN-SPS test-beam facility (120 GeV π⁺ particles) in July 2016 and October 2016. The time-of-flight (ToF) detector in conjunction with a 3D silicon pixel tracker will tag and measure protons originating in central exclusive interactions p + p → p + X + p, where the two outgoing protons are scattered in the very forward directions. The ToF is required to reduce so-called pileup backgrounds that arise from multiple proton interactions in the same bunch crossing at high luminosity. The background can fake the signal of interest, and the extra rejection from the ToF allows the proton tagger to operate at the high luminosity required for the measurement of the processes. The prototype detector uses fused silica bars emitting Cherenkov radiation as a relativistic particle passes through them. The emitted Cherenkov photons are detected by a multi-anode micro-channel plate photomultiplier tube (MCP-PMT) and processed by fast electronics.

The MiniACcor: Constructive Redesign of an Implantable Total Artificial Heart, Initial Laboratory Testing and Further Steps

The Aachen Total Artificial Heart (ACcor) has been under development at the Helmholtz Institute in Aachen over the last decade. It may serve as a bridge to transplant or as a long-term replacement of the natural heart. Based upon previous in vivo experiments with the ACcor total artificial heart, it was decided to optimize and redesign the pump unit. Smaller dimensions, passive filling and separability into three components were the three main design goals. The new design is called the MiniACcor, which is about 20% smaller than its predecessor, and weighs only 470 grams. Also its external driver/control unit was miniaturized and a new microcontroller was selected. To validate the design, it was extensively tested in laboratory mock loops. The MiniACcor was able to pump between 4.5 and 7 l/min at different pump rates against normal physiological pressures. Several requirements for the future compliance chamber and transcutaneous energy transmission (TET) system were also measured in the same mock loop. Further optimization and validation are being performed in cooperation with the Heart and Diabetes Centre North Rhine-Westphalia.

Abstract P4-13-07: Impact of physical activity/exercise on adverse events and quality of life during treatment with everolimus and exemestane for ER+ women - Results of the 3rd interim analysis of BRAWO

Introduction

BRAWO is a non-interventional study collecting data of 3000 breast cancer patients treated with everolimus and exemestane (advanced or metastatic, hormone-receptor-positive, HER2-negative breast cancer). We introduce results of the 3rd preplanned interim analysis with data cut-off 08/01/ 2015, including 1300 patients. Since physical activity/exercise was reported to influence side effects as well as quality of life (QoL) of various cancer types and therapies, this analysis focuses on the impact of the physical activity/exercise history, development on adverse effects (AE) of the medical treatment and QoL.

Methods

Patients were asked to complete the EORTC QLQ-C30 QoL questionnaire and visual analogue scales (VAS-KAS) measuring their present-, past ten year- and lifetime physical activity/exercise level. To differentiate between activity/exercise levels, VAS were divided in three equal components (inactive, somewhat active, very active). Questionnaires and information about AE (e. g. stomatitis, fatigue, nausea, diarrhea, etc.) were collected before starting the medical treatment and were repeated each three months. Logistic regression model was used to estimate the impact of baseline physical activity/exercise on AE at any time point of the therapy. ANOVA models were used to calculate the impact of the baseline activity/exercise level on QoL at the last completed data set of each patient.

Results

Median age of patients was 66 years, median weight was 70 kg, median BMI was 25.9, median time since primary diagnosis was 6.2 years, and 54.4% had visceral metastases at baseline. The median PFS for the first 1300 patients was 7.1 months (95% CI, 6.5-8.0). Patients who reported to be very active (exercise) at the week prior to baseline (4.4%) showed significant lower numbers of AE compared to patients who indicate to be somewhat (14.8%) or inactive (80.8%). In contrast to the exercise level, physical activity in everyday life did not affect the AE incidence. Neither lifetime nor past ten year activity/exercise level is associated with the occurrence of AE. Regarding QoL, very active as well as somewhat active women (measured at baseline for almost each time period) showed significant higher QoL values compared to inactive women during the last assessment before death/progress.

Conclusion

Exercise prior to medical treatment with Everolimus and Exemestane may impact AE during therapy. Since physical activity did not show such a relation, this analysis highlights the importance of specific guidelines for preventive/rehabilitative exercise programs. More knowledge about dose-response relationships is needed. Furthermore a livelong healthy, "active" lifestyle may increase QoL, even in patients with advanced and terminal breast cancer disease.

Citation Format: Bloch W, Baumann F, Zimmer P, Grischke E-M, Fasching PA, Decker T, Uleer C, Schneeweiss A, Salat C, Wimberger P, Mundhenke C, Förster F, Kluth-Pepper B, Schubert J, Tesch H, Schütz F, Lüftner D, Jackisch C. Impact of physical activity/exercise on adverse events and quality of life during treatment with everolimus and exemestane for ER+ women - Results of the 3rd interim analysis of BRAWO. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-13-07.

Abstract P4-13-06: Results of the 3rd interim analysis of the non-interventional trial BRAWO – Subanalysis of patients <70 years and ≥ 70 years

Background

BRAWO is a German non-interventional study of 3000 patients (pts) with advanced/metastatic, hormone-receptor-positive and HER2-negative breast cancer treated with everolimus and exemestane (EVE+EXE). The pivotal BOLERO-2 trial demonstrated that adding EVE to EXE improved PFS over EXE and was generally well tolerated in elderly patients with HR+ advanced breast cancer (>65 years as well as >70 years). Here we describe data of elderly patients treated with EVE+EXE in daily clinical routine.

Methods

We report data of the 3rd preplanned interim analysis (IA) of the first 1300 pts documented in BRAWO. Patient and disease characteristics in elderly patients (≥ 70 years, n=485) and patients <70 years (n=813) are described. Furthermore, safety and efficacy data for both subgroups are described.

Results

At time of data cut-off, 71% pts had discontinued the study, 29% were still ongoing. Patient and disease characteristics were comparable in both groups except for: median age (60y (range: 20-69y) vs. 75y (range 70-93y)), median time since 1st diagnosis (6.4y <70y vs. 8.8y ≥70 y), ECOG performance status 0 (56.6% <70y vs. 37.0% ≥70 y), and younger pts seemed to have less comorbidities (charlson comorbidity index (CCI)=0: 80.9% vs. 67.4%). The distribution of patients by therapy line was similar as well as tumor grading, hormone receptor status, Ki67-status and metastasis localization.

More patients in the older group received fulvestrant (20.6% vs. 16.2%), in the younger group more patients received chemotherapy (20.3% vs. 14.2%) as last antineoplastic therapy. In general, more patients in the older subgroup did not receive any chemotherapy as pretreatment (53.6% vs 40.2%).

More patients in the subgroup ≥70y received 5mg EVE as starting dose (30.3% vs. 20.8%) and had 5mg as end dose (37.9% vs. 26.9%). Median PFS was 7.1 months in the overall population, 7.0 months (6.5, 8.0; 95%CI) for pts <70y and 7.3 months (6.3, 8.6; 95%CI) for pts ≥70y. Kaplan Meier estimates for median treatment duration were longer for younger pts (167.0 days (155.0, 191.0; 95%CI vs. 128.0 days (112.0, 152.0; 95%CI)). Incidence and severity of stomatitis were comparable across subgroups (Table 1). Quality of life analysis revealed no significant differences between older and younger pts.

Table 1: Incidence and severity of stomatitis

Patient Characteristics< 70 years (n=813)≥ 70 years (n=485)Stomatitis  Number of patients with at least one Stomatitis Event (based on stomatitis questionnaires)339 (41.7%)200 (41.2%)Grade 1181 (22.3%)95 (19.6%)Grade 2119 (14.6%)79 (16.3%)Grade 319 (2.3%)11 (2.3%)unknown20 (2.5%)15 (3.1%)Number of Stomatitis Events431 (100.0%)252 (100%)Grade 1237 (55.0%)125 (49.6%)Grade 2136 (31.6%)87 (34.5%)Grade 319 (4.4%)13 (5.2%)

Discussion

The data described here show that EVE+EXE treatment is effective and safe for elderly patients in daily clinical routine. This is consistent with data from an exploratory analysis of the pivotal BOLERO-2 trial, where the same differences in baseline characteristics were observed for elderly pts compared to younger pts as in BRAWO. Efficacy was also comparable to elderly pts in BOLERO-2 (mPFS 6.8 months for EVE+EXE in pts ≥70 years).

Citation Format: Tesch H, Grischke E-M, Fasching PA, Decker T, Uleer C, Schneeweiss A, Salat C, Wimberger P, Mundhenke C, Förster F, Kluth-Pepper B, Schubert J, Bloch W, Jackisch C, Schütz F, Lüftner D. Results of the 3rd interim analysis of the non-interventional trial BRAWO – Subanalysis of patients <70 years and ≥ 70 years. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-13-06.

Abstract P4-14-08: Efficacy of trastuzumab re-therapy in the clinical routine of HER2-positive breast cancer patients who relapsed after completed anti-HER2 (neo)adjuvant therapy – 5th interim analysis of the national non-interventional study (NIS) ML21589

Background

HER2 overexpression occurs in approx. 20% of breast tumors and is associated with increased aggressiveness and mortality. Anti-HER2 re-therapy with trastuzumab (Herceptin®, T) is an established therapeutic option for the treatment of recurrent/metastatic HER2-positive breast cancer (MBC). Patients (pts) receiving T re-therapy appear to benefit from the retreatment after a relapse-free (neo)adjuvant anti-HER2 therapy.

Methods

This NIS is conducted in Germany to gain additional knowledge about efficacy of 1st-line T retreatment in the clinical routine. 122 sites enrolled a total of 239 pts with locally recurrent and/or MBC who relapsed after (neo)adjuvant treatment with T in their medical history. 230 pts met the eligibility criteria. The current analysis presents data collected between 10/2008-04/2015. Tumor progression was clinically assessed by the investigator.

Results

Median observation period for the total population (n=230) was 41.7 months (m) (range 0.4-94.5).

At start of T retreatment, 20.0% (n=46) of the pts presented with local recurrence only, 79.6% (n=183) presented with distant metastases ± local recurrence and one patient (0.4%) presented with elevated tumor markers. 27.4% (n=63) of the pts developed exclusively non-visceral metastases and 52.2% (n=120) were diagnosed with visceral (± non-visceral) metastases. Median duration of T re-therapy in the first line setting was 9.0 m (95% confidence interval (CI): 7.6-10.1). In 69.6% (n=160) of the cases, T was added to chemotherapy (CT). 15.2% of the pts (n=35) were treated with T+CT + endocrine therapy (ET).

A median progression free survival (PFS) of 10.1 m was observed among all eligible patients (n = 230) (95% CI: 8.5-12.0). The evaluation by risk groups revealed a PFS of 23.7 m (95% CI: 13.3-NE*) for patients with local recurrence only, 11.8 m (95% CI: 8.3-20.1) for patients with non-visceral metastases and 7.6 m (95% CI: 6.2-9.9) for patients with visceral metastases. *Not evaluable

Median PFS according to treatment regimen was 8.3 m for pts who were treated with T+CT (n=125, 54.3%), 17.7 m in pts who received T+CT+ET (n=35, 15.2%) and 11.2 m in pts treated with T+ET (n=38, 16.5%). Pts who received T monotherapy (n=32, 13.9%) had a median PFS of 13.4 m.

Of 230 pts, 121 deaths were documented (52.6%) within the observation period. The median overall survival (OS) was 29.6 m for all pts (95% CI: 27.3-36.8). Median OS was statistically reliable for pts with visceral metastases only: 19.4 m (95% CI: 16.9-27.3). The 2-year survival rate was 62.2% for all pts, 81.9% for pts with local recurrence only, 80.7% for pts with non-visceral metastases and 45.6% for pts with visceral metastases.

Conclusions

The survival observed for pts with HER2-positive MBC receiving T re-therapy in the clinical routine is in line with the results of recently published data. In terms of the 2-year survival rate, 81.9% of the pts with local recurrence were still alive and thus show the most favourable prognosis. T re-therapy provides an efficient treatment option regardless of given as combination-therapy together with CT and/or ET or as monotherapy.

Citation Format: Hanker L, Hitschold T, Grafe A, Förster F, Schröder J, Janssen J, Reichert D, Hielscher C, Keitel S, Hesse T. Efficacy of trastuzumab re-therapy in the clinical routine of HER2-positive breast cancer patients who relapsed after completed anti-HER2 (neo)adjuvant therapy – 5th interim analysis of the national non-interventional study (NIS) ML21589. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-14-08.

In vitro anti-cancer effects of the actin-binding natural compound rhizopodin

Several natural compound interfere with microtubules or the actin cytoskeleton. Compounds interfering with the microtubules like Vinca-alkaloids or taxanes, are extensively used for cancer therapy. In contrast, knowledge about pharmacological properties of actin binding drugs is poor and drugs interfering with actin are far from clinical use. Rhizopodin is a natural compound that strongly affects the actin cytoskeleton at nanomolar concentrations. Initial work revealed interesting anti-bacterial and cytotoxic effects, but the cellular effects and pharmacological properties of rhizopodin have not been characterized. We hypothesized that rhizopodin might exert anti-cancer activity. Therefore, the aim of this study was to characterize the cellular and pharmacological effects of rhizopodin in cancer. Effects of rhizopodin demonstrated prominent effects on the actin cytoskeleton as shown in the actin-pyrene assay and by immunostaining of cancer cells. To investigate cellular effects of rhizopodin, we analyzed cell proliferation, cell death induction by propidium iodide exclusion and western blot, as well as migration by impedance measurement using the xCELLligence device in MDA-MB-231 breast cancer and T24 bladder cancer cell lines. Rhizopodin inhibited proliferation and induced cell death of MDA-MB-231 and T24 cells at nanomolar concentrations. PARP cleavage by rhizopodin suggests caspase-dependent cell death induction. Importantly, rhizopodin potently inhibited MDA-MB-231 and T24 cancer cell migration at subtoxic doses where no actin aggregation was observed, indicating a specific underlying signaling of rhizopodin. In summary, our study elucidates rhizopodin as actin-binding natural compound that exerts potent anti-cancer effects. Therefore, our work provides the basis for further in depth characterization of rhizopodin as an antitumoral agent.

Abstract P2-16-03: Mature results on metastatic breast cancer patients with prolonged (≥1 year) exposure to first-line bevacizumab combined with paclitaxel from a large observation study

Background: Bevacizumab (BEV) combined with chemotherapy (CT) significantly improves progression-free survival (PFS) and response rate (RR) vs CT alone in the 1st-line treatment of HER2-negative metastatic breast cancer (mBC). BEV was continued for ≥1 year in 20% of patients (pts) in the global ATHENA safety study. We examined a similar subgroup of pts with long-term antibody treatment in a large German observation study. Meanwhile, long-term follow-up of up to 4.5 years allows to present the final results, including mature data on overall survival.

Methods: Pts who had received no prior CT for their mBC received BEV-PAC per the European label. Efficacy and safety were documented in detail for up to 1 year (or until progression, death, or BEV discontinuation if earlier), with subsequent retrieval of long-term follow-up.

Results: By April 2013, final data were available for 865 pts, of whom 167 (20%) were recorded to have received BEV for ≥1 year. Baseline characteristics of this subset relative to the overall population are summarized in the table.

CharacteristicOverall population (n = 865)Subgroup treated with BEV for ≥1 year (n = 167)Median age, years (range)58(26-87)57(28-79)Age ≥65 years,%3230Metastatic at diagnosis,%2018Disease-free inreval <12 months,%24*14#Liver metastasis,%4235≥3 metastatic sites,%3329Triple-negative disease,%1812ECOG performance status >1,%98Prior (neo)adjuvant chemotherapy,%6661*n = 591, initially M0. #n = 113

Dose reductions of long-term BEV occurred in only 3% of cycles and (at least once) in 17% of pts. In the majority of pts treated for ≥1 year, BEV was continued as a single agent after discontinuation of CT. The overall best RR in pts treated for ≥1 year was 80% (complete response in 19%). Median PFS, based on observed events in 83% of all pts, was 18.4 months compared to 9.6 months in the overall population. Overall survival data, based on 524 deaths (61%), show a median of 21.6 months. In the subgroup with prolonged therapy, median OS amounts to 35.7 months with 40% of pts still alive after 4 years. Safety of long-term BEV is as previously reported with only a slightly increased hypertension rate (35%, grade ≥3: 11%), and no cases of gastrointestinal perforation, arterial thromboembolic event, or reversible posterior leukoencephalopathy syndrome.

Conclusions: According to the mature data of this study, including those on OS, a notable proportion of pts appear to derive benefit from prolonged exposure to first-line BEV-containing therapy. Although baseline characteristics exhibited only moderate indicators for an a priori more favorable prognostic profile in the subset of pts treated for ≥1 year, of course one has to keep in mind, that time-related efficacy data are biased towards improved outcome in those able to continue BEV for ≥1 year. However, the median survival of almost 3 years suggests that in a considerable number of pts continued first-line BEV-PAC correlates to favorable outcomes with limited adverse effects.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-16-03.

A small pulsatile blood pump for ventricular support during end-stage heart failure

A displacement blood pump to support the natural heart of patients for recovery from end-stage heart failure has been developed. This electromechanical pusher plate pump has a very compact and extremely flat design. The design goal was achieved by developing a novel gear system based on the principle of a swash plate. The blood pump and cannulae can be placed within the thoracic cavity between the lungs and ribcage. The first labtype model delivers an output of 3.1 L/min against an aortic pressure of 100 mm Hg at 120 bpm.

Serum magnesium in insulin-dependent diabetics and healthy subjects in relation to insulin secretion and glycemia during glucose-glucagon test

In order to investigate the influence of insulin secretion on serum magnesium concentrations 33 insulin-dependent diabetics and 10 control subjects were studied. The residual insulin secretion (RIS) was investigated by measurement of human C-peptide (HCP) before and after stimulation during on OGTT (1.75 mg/kg)-glucagon (i.v. 0.1 mg glucagon/kg)-test.

RESULTS

Certain RIS existed in 11 insulin-dependent diabetics, 12 were without any RIS (uncertain RIS in 10 patients). Glucose tolerance and daily glycemia differed significantly among the two groups. However, all diabetics were far from euglycemia, (3.3-9.3 mmol/l): Fasting plasma glucose 12.0 +/- 0.9 (certain RIS), 15.0 +/- 0.8 (no RIS), 13.9 +/- 1.8 (uncertain RIS). Serum magnesium was significantly lower in all diabetics, both before and during the test. There was no change during the OGTT-glucagon-test and no difference among the three groups of insulin-dependent diabetics. So, we conclude that a small RIS in our longterm insulin-dependent diabetics has no influence on the behaviour of serum magnesium. But, magnesium depletion can influence coronary blood flow, blood clotting, and atherogenesis. Therefore, it should be necessary to pay more attention to the hypomagnesemia in insulin-dependent diabetics.