Randomized phase-III study of low-dose cytarabine and etoposide + /- all-trans retinoic acid in older unfit patients with NPM1-mutated acute myeloid leukemia

The aim of this randomized clinical trial was to evaluate the impact of all-trans retinoic acid (ATRA) in combination with non-intensive chemotherapy in older unfit patients (> 60 years) with newly diagnosed NPM1-mutated acute myeloid leukemia. Patients were randomized (1:1) to low-dose chemotherapy with or without open-label ATRA 45 mg/m2, days 8-28; the dose of ATRA was reduced to 45 mg/m2, days 8-10 and 15 mg/m2, days 11-28 after 75 patients due to toxicity. Up to 6 cycles of cytarabine 20 mg/day s.c., bid, days 1-7 and etoposide 100 mg/day, p.o. or i.v., days 1-3 with (ATRA) or without ATRA (CONTROL) were intended. The primary endpoint was overall survival (OS). Between May 2011 and September 2016, 144 patients (median age, 77 years; range, 64-92 years) were randomized (72, CONTROL; 72, ATRA). Baseline characteristics were balanced between the two study arms. The median number of treatment cycles was 2 in ATRA and 2.5 in CONTROL. OS was significantly shorter in the ATRA compared to the CONTROL arm (p = 0.023; median OS: 5 months versus 9.2 months, 2-years OS rate: 7% versus 10%, respectively). Rates of CR/CRi were not different between treatment arms; infections were more common in ATRA beyond treatment cycle one. The addition of ATRA to low-dose cytarabine plus etoposide in an older, unfit patient population was not beneficial, but rather led to an inferior outcome.The clinical trial is registered at clinicaltrialsregister.eu (EudraCT Number: 2010-023409-37, first posted 14/12/2010).

Singlet-Oxygen-Induced Phospholipase A2 Inhibition: A Major Role for Interfacial Tryptophan Dioxidation

Several studies have revealed that various diseases such as cancer have been associated with elevated phospholipase A2 (PLA2 ) activity. Therefore, the regulation of PLA2 catalytic activity is undoubtedly vital. In this study, effective inactivation of PLA2 due to reactive species produced from cold physical plasma as a source to model oxidative stress is reported. We found singlet oxygen to be the most relevant active agent in PLA2 inhibition. A more detailed analysis of the plasma-treated PLA2 identified tryptophan 128 as a hot spot, rich in double oxidation. The significant dioxidation of this interfacial tryptophan resulted in an N-formylkynurenine product via the oxidative opening of the tryptophan indole ring. Molecular dynamics simulation indicated that the efficient interactions between the tryptophan residue and phospholipids are eliminated following tryptophan dioxidation. As interfacial tryptophan residues are predominantly involved in the attaching of membrane enzymes to the bilayers, tryptophan dioxidation and indole ring opening leads to the loss of essential interactions for enzyme binding and, consequently, enzyme inactivation.

Gas Plasma Technology Augments Ovalbumin Immunogenicity and OT-II T Cell Activation Conferring Tumor Protection in Mice

Reactive oxygen species (ROS/RNS) are produced during inflammation and elicit protein modifications, but the immunological consequences are largely unknown. Gas plasma technology capable of generating an unmatched variety of ROS/RNS is deployed to mimic inflammation and study the significance of ROS/RNS modifications using the model protein chicken ovalbumin (Ova vs oxOva). Dynamic light scattering and circular dichroism spectroscopy reveal structural modifications in oxOva compared to Ova. T cells from Ova-specific OT-II but not from C57BL/6 or SKH-1 wild type mice presents enhanced activation after Ova addition. OxOva exacerbates this activation when administered ex vivo or in vivo, along with an increased interferon-gamma production, a known anti-melanoma agent. OxOva vaccination of wild type mice followed by inoculation of syngeneic B16F10 Ova-expressing melanoma cells shows enhanced T cell number and activation, decreased tumor burden, and elevated numbers of antigen-presenting cells when compared to their Ova-vaccinated counterparts. Analysis of oxOva using mass spectrometry identifies three hot spots regions rich in oxidative modifications that are associated with the increased T cell activation. Using Ova as a model protein, the findings suggest an immunomodulating role of multi-ROS/RNS modifications that may spur novel research lines in inflammation research and for vaccination strategies in oncology.

Frequency-Independent Terahertz Anomalous Hall Effect in DyCo5 , Co32 Fe68 , and Gd27 Fe73 Thin Films from DC to 40 THz

The anomalous Hall effect (AHE) is a fundamental spintronic charge-to-charge-current conversion phenomenon and closely related to spin-to-charge-current conversion by the spin Hall effect. Future high-speed spintronic devices will crucially rely on such conversion phenomena at terahertz (THz) frequencies. Here, it is revealed that the AHE remains operative from DC up to 40 THz with a flat frequency response in thin films of three technologically relevant magnetic materials: DyCo₅ , Co₃₂ Fe₆₈ , and Gd₂₇ Fe₇₃ . The frequency-dependent conductivity-tensor elements σ_xx and σ_yx  are measured, and good agreement with DC measurements is found. The experimental findings are fully consistent with ab initio calculations of σ_yx for CoFe and highlight the role of the large Drude scattering rate (≈100 THz) of metal thin films, which smears out any sharp spectral features of the THz AHE. Finally, it is found that the intrinsic contribution to the THz AHE dominates over the extrinsic mechanisms for the Co₃₂ Fe₆₈ sample. The results imply that the AHE and related effects such as the spin Hall effect are highly promising ingredients of future THz spintronic devices reliably operating from DC to 40 THz and beyond.

Interaction of fibrinogen-magnetic nanoparticle bioconjugates with integrin reconstituted into artificial membranes

Magnetic nanoparticles have a broad spectrum of biomedical applications including cell separation, diagnostics and therapy. One key issue is little explored: how do the engineered nanoparticles interact with blood components after injection? The formation of bioconjugates in the bloodstream and subsequent reactions are potentially toxic due to the ability to induce an immune response. The understanding of the underlying processes is of major relevance to design not only efficient, but also safe nanoparticles for e.g. targeted drug delivery applications. In this study, we report on maghemite nanoparticles functionalized with citrate-, dextran- and polyethylene glycol coatings and their interaction with the clotting protein fibrinogen. Further, we investigate using biophysical tools (e.g. dynamic light scattering, circular dichroism spectroscopy and quartz crystal microbalance) the interaction of the magnetic nanoparticles-fibrinogen bioconjugates with artificial cell membranes as a model system for blood platelets. We found that fibrinogen corona formation provides colloidal stability to maghemite nanoparticles. In addition, bioconjugates of fibrinogen with dextran- and citrate-coated NPs interact with integrin-containing lipid bilayer, especially upon treatment with divalent ions, whereas PEG-coating reveals minor interaction. Our study at the interface of protein-conjugated nanoparticles and artificial cell membranes is essential for engineering safe nanoparticles for drug delivery applications.

Maghemite nanoparticles stabilize the protein corona formed with transferrin presenting different iron-saturation levels

Magnetic nanoparticles are ideal candidates for biomedical applications given their potential use in magnetic resonance imaging, magnetic hyperthermia and targeted drug delivery. Understanding protein-nanoparticle interactions in the blood stream is of major importance due to their potential risks, especially immunogenicity (i.e. the ability to induce an immune response). Here, we report on the interaction of superparamagnetic maghemite (γ-Fe2O3) nanoparticles with human blood plasma protein transferrin presenting different iron-saturation levels: partially iron-saturated (i.e. transferrin) and iron-free transferrin (i.e. apotransferrin). The nanoparticle-protein interaction and the protein corona formation were studied using biophysical and chemical approaches based on dynamic light scattering, gel electrophoresis, circular dichroism spectroscopy and differential scanning fluorimetry. We found that iron content governs the protein corona formation and induces a strong effect on the thermal stability of the bound protein. Our results demonstrate a stabilizing effect of the nanoparticles with a change of the unfolding position of approximately 10 °C towards higher temperatures for transferrin. Our study may be relevant for the further development of magnetic nanoparticles as diagnostic and therapeutic tools.

Small molecule PGC-1α1 protein stabilizers induce adipocyte Ucp1 expression and uncoupled mitochondrial respiration

Objective

The peroxisome proliferator-activated receptor-γ coactivator-1α1 (PGC-1α1) regulates genes involved in energy metabolism. Increasing adipose tissue energy expenditure through PGC-1α1 activation is potentially beneficial for systemic metabolism. Pharmacological PGC-1α1 activators could be valuable tools in the fight against obesity and metabolic disease. Finding such compounds has been challenging partly because PGC-1α1 is a transcriptional coactivator with no known ligand-binding properties. While, PGC-1α1 activation is regulated by several mechanisms, protein stabilization is a crucial limiting step due to its short half-life under unstimulated conditions.

Methods

We designed a cell-based high-throughput screening system to identify PGC-1α1 protein stabilizers. Positive hits were tested for their ability to induce endogenous PGC-1α1 protein accumulation and activate target gene expression in brown adipocytes. Select compounds were analyzed for their effects on global gene expression and cellular respiration in adipocytes.

Results

Among 7,040 compounds screened, we highlight four small molecules with high activity as measured by: PGC-1α1 protein accumulation, target gene expression, and uncoupled mitochondrial respiration in brown adipocytes.

Conclusions

We identify compounds that induce PGC-1α1 protein accumulation and show that this increases uncoupled respiration in brown adipocytes. This screening platform establishes the foundation for a new class of therapeutics with potential use in obesity and associated disorders.

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A high-throughput platform to identify PGC-1α1 activators.

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PGC-1α1 protein stabilizers work as activators in brown adipocytes.

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Small molecule PGC-1α1 activators induce Ucp1 expression and cellular respiration.

Large magneto-Seebeck effect in magnetic tunnel junctions with half-metallic Heusler electrodes

Spin caloritronics studies the interplay between charge-, heat- and spin-currents, which are initiated by temperature gradients in magnetic nanostructures. A plethora of new phenomena has been discovered that promises, e.g., to make wasted heat in electronic devices useable or to provide new read-out mechanisms for information. However, only few materials have been studied so far with Seebeck voltages of only some microvolt, which hampers applications. Here, we demonstrate that half-metallic Heusler compounds are hot candidates for enhancing spin-dependent thermoelectric effects. This becomes evident when considering the asymmetry of the spin-split density of electronic states around the Fermi level that determines the spin-dependent thermoelectric transport in magnetic tunnel junctions. We identify Co₂FeAl and Co₂FeSi Heusler compounds as ideal due to their energy gaps in the minority density of states, and demonstrate devices with substantially larger Seebeck voltages and tunnel magneto-Seebeck effect ratios than the commonly used Co-Fe-B-based junctions.

Analysis of the time-resolved magneto-optical Kerr effect for ultrafast magnetization dynamics in ferromagnetic thin films

We discuss fundamental aspects of laser-induced ultrafast demagnetization probed by the time-resolved magneto-optical Kerr effect (MOKE). Studying thin Fe films on MgO substrate in the absence of electronic transport, we demonstrate how to disentangle pump-induced variations of magnetization and magneto-optical coefficients. We provide a mathematical formalism for retrieving genuine laser-induced magnetization dynamics and discuss its applicability in real experimental situations. We further stress the importance of temporal resolution achieved in the experiments and argue that measurements of both time-resolved MOKE rotation and ellipticity are needed for the correct assessment of magnetization dynamics on sub-picosecond timescales. The framework developed here sheds light onto the details of the time-resolved MOKE technique and contributes to the understanding of the interplay between ultrafast laser-induced optical and magnetic effects.

Light-Induced Metastable Magnetic Texture Uncovered by in situ Lorentz Microscopy

Magnetic topological defects, such as vortices and Skyrmions, can be stabilized as equilibrium structures in nanoscale geometries and by tailored intrinsic magnetic interactions. Here, employing rapid quench conditions, we report the observation of a light-induced metastable magnetic texture, which consists of a dense nanoscale network of vortices and antivortices. Our results demonstrate the emergence of ordering mechanisms in quenched optically driven systems, which may give a general access to novel magnetic structures on nanometer length scales.

Pretransplant NPM1 MRD levels predict outcome after allogeneic hematopoietic stem cell transplantation in patients with acute myeloid leukemia

The objective was to evaluate the prognostic impact of pre-transplant minimal residual disease (MRD) as determined by real-time quantitative polymerase chain reaction in 67 adult NPM1-mutated acute myeloid leukemia patients receiving allogeneic hematopoietic stem cell transplantation (HSCT). Twenty-eight of the 67 patients had a FLT3-ITD (42%). Median age at transplantation was 54.7 years, median follow-up for survival from time of allografting was 4.9 years. At transplantation, 31 patients were in first, 20 in second complete remission (CR) and 16 had refractory disease (RD). Pre-transplant NPM1 MRD levels were measured in 39 CR patients. Overall survival (OS) for patients transplanted in CR was significantly longer as compared to patients with RD (P=0.004), irrespective of whether the patients were transplanted in first or second CR (P=0.74). There was a highly significant difference in OS after allogeneic HSCT between pre-transplant MRD-positive and MRD-negative patients (estimated 5-year OS rates of 40 vs 89% P=0.007). Multivariable analyses on time to relapse and OS revealed pre-transplant NPM1 MRD levels >1% as an independent prognostic factor for poor survival after allogeneic HSCT, whereas FLT3-ITD had no impact. Notably, outcome of patients with pre-transplant NPM1 MRD positivity >1% was as poor as that of patients transplanted with RD.

3D Micropillars Guide the Mechanobiology of Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes

3D micropillars generated by photolithography are used as a platform to probe by atomic force microscopy the mechanodynamics of human induced pluripotent stem cell-derived cardiomyocytes. 3D micropillars guide subcellular cytoskeletal modifications of cardiomyocytes and lead to biochemical changes altering beating rate, stiffness, and calcium dynamics of the cells.

[Probiotic therapy of the irritable bowel syndrome]

The irritable bowel syndrome (IBS) is among the most common disorders in gastroenterological practice with a prevalence of approx. 12 % in Germany, and it is characterized by abdominal pain or discomfort, altered stool frequency and consistency, and meteorism and bloating. There is currently no agreement between those seeing patients with IBS (general practitioner, gastroenterologist, psychosomatics) on the criteria for clinical diagnosis. Metaanalyses of treatment studies in IBS have shown that probiotics have a high clinical efficacy in IBS, especially since development of novel pharmaceutical compounds have not reached the market or have been withdrawn. In addition to the actual status of probiotic efficacy in IBS studies conducted worldwide, we present 3 German clinical studies with probiotic E.COLI preparations that have proven their efficacy in IBS in adults and in children.

Probiotic treatment of irritable bowel syndrome in children

Treatment of functional bowel disorders of irritable bowel-type (IBS) in children remains a difficult task because of a lack of drugs with low adverse event profile. We here report the results of a treatment study in 203 children (66 boys and 137 girls) age 4 to 18 years (mean: 10.5+/-4.5 years) with typical IBS symptoms with abdominal pain and either predominant diarrhea (n=50), constipation (n=56), alternating stool frequency (n=28) or unspecific pain (n=69). The average duration of symptoms prior to therapy was 175 days. Most (95%) patients up to age 11 were treated with a daily dose of 10 drops of Symbioflor 2 (SF2) (SymbioPharm, Herborn) (cells and autolysate of 1.5-4.5x10(7) CFU of bacteria of Escherichia coli type), in the elder children 77% received this dosage, while the remaining received a higher dose up to 30 drops/day. Treatment lasted 43 days on average.

RESULTS

All patients tolerated the treatment well and without adverse events. The key IBS symptoms (abdominal pain, stool frequency) as well as the other symptoms (bloating, mucous and blood in stool, need for straining at stools, urge to defecate) improved significantly during treatment. Global assessment of therapy by parents and doctors was altogether positive. In summary these data confirm efficacy and tolerability of this probiotic compound in children and adolescents and supplement published data of probiotic IBS therapy in adults.

[Hypnotherapy for irritable bowel syndrome--a systematic review]

The Irritable bowel syndrome (IBS) is a highly prevalent functional disorder with a remarkable clinical and economic impact. Several pathogenetic factors of IBS are discussed and summarised within a bio-psycho-social model. Data from published hypnotherapeutic interventions with approximately 800 patients show long-lasting symptom relief. The underlying mechanisms of action are not well understood. Nine mechanism studies show influences of hypnosis on colorectal sensitivity, colorectal motility and mental strain (anxiety, depression, maladaptive cognitions). Results are often contradictory and effects of hypnosis on several of the proposed pathogenetic factors are not examined at all. This paper reviews previous studies on hypnotherapy in IBS patients with a focus on symptom relief and mechanisms of action.

[Fear of allowing sugar into the cell--case 05/2009. Comorbidity of diabetes mellitus and eating disorders]

HISTORY AND ADMISSION FINDINGS

An 19-year-old female patient was admitted to our department of psychosomatic medicine and psychotherapy for the treatment of her metabolically deranged type 1 diabetes mellitus.

INVESTIGATIONS

Exploration and assessment revealed a typical eating disorder symptomatology. The body mass index at time of admission was 18.7 kg/m (2). Episodes of binge eating were followed by purging behaviour (insulin purging, vomiting).

DIAGNOSIS, TREATMENT AND COURSE

After diagnosis of bulimia nervosa, the patient was treated with a structured dual treatment regime consisting of psychosomatic/psychotherapeutic interventions and endocrinological support. The existing complex bio-psycho-social conditions were considered carefully. In the treatment course typical eating disorder behaviour (i. e. insulin purging) decreased and mood stabilised.

CONCLUSIONS

Adolescent women with diabetes mellitus are at an increased risk of developing an eating disorder. This comorbidity is associated with a markedly increased mortality. Therefore, diagnosis of an eating disorder should be made as soon as possible in order to provide adequate treatment not only for the metabolic disturbances but also for the coexisting psychosomatic disorder.

Molecular and clinical predictors of outcome for cetuximab in non-small cell lung cancer (NSCLC): Data from the FLEX study

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Background: The multinational, randomized, phase III FLEX study compared cisplatin/vinorelbine (CT) plus the EGFR- antibody, cetuximab (Erbitux), with CT alone in the 1st-line treatment of patients (pts) with advanced EGFR-expressing NSCLC and demonstrated a statistically significant OS benefit for the cetuximab combination. We hypothesized that KRAS mutation status is predictive for cetuximab efficacy and enables optimal use of cetuximab. The relationship between early-onset acne-like rash (ie rash that developed ≤21 days of treatment initiation) and OS time of pts treated with CT and cetuximab was also evaluated. Methods: Archived tumor samples from 554/1125 pts were available. Genomic DNA derived from formalin-fixed paraffin embedded tumor tissue was analyzed for KRAS using an LNA-mediated qPCR clamping assay capable of detecting oncogenic mutations at codons 12 and 13. The Kaplan-Meier method was used to estimate OS time and PFS time in pts with KRAS wild-type (wt) and mutant (mt) tumors for each treatment arm. All pts treated with cisplatin/vinorelbine plus cetuximab who were alive at 21 days were included in a landmark analysis evaluating the relationship between early-onset acne-like rash and OS time. Results: KRAS results were obtained from 379 pts. A KRAS mutation was detected in 72 (19%) pts. The comparison of the cetuximab treatment effects in pts with KRAS wt tumors and pts with KRAS mt tumors showed no marked differences with regard to OS or PFS. A total of 518 pts were included in the landmark analysis. Pts treated with cetuximab who developed early acne-like rash of any grade (grade 1–3; 56%, n=290) had a longer median OS than those without acne-like rash (n=228) (median [95% CI]: 15.0 months [12.8–16.4] vs 8.8 months [7.6–11.1]; HR [95% CI]: 0.63 [0.52–0.77]; p<0.001). Analysis of EGFR FISH is ongoing and results will be presented. Conclusions: Clinical data from the FLEX study do not support the hypothesis that KRAS mutation status is predictive for cetuximab efficacy when combined with 1st- line chemotherapy in advanced NSCLC, whereas early acne-like rash of any grade appears to be associated with better outcome in pts treated with platinum-based chemotherapy plus cetuximab in this setting.

[Table: see text]

A mixture of Escherichia coli (DSM 17252) and Enterococcus faecalis (DSM 16440) for treatment of the irritable bowel syndrome--a randomized controlled trial with primary care physicians

Therapy trials with bacterial compounds in irritable bowel syndrome (IBS) have produced conflicting results. This study was performed in 1988 and 1989, and was re-analysed according to current IBS standards. Two hundred ninety-seven patients with lower abdominal symptoms diagnosed as IBS were treated for 8 weeks by the compound ProSymbioflor((R)) (Symbiopharm GmbH, Herborn, Germany), an autolysate of cells and cell fragments of Enterococcus faecalis and Escherichia coli, or placebo in a double-blinded, randomized fashion. Patients were seen weekly by the physician, who assessed the presence of core IBS symptoms. Responders had at least a 50% decrease in global symptom score (GSS) and in abdominal pain score (APS) reports at >/=1 visit during treatment. The responder rate in GSS to the drug was 102/149 (68.5%) in comparison to placebo with 56/148 (37.8%) (P < 0.001), the improvement in APS was 108/149 (72.5%) and 66/148 (44.6%) respectively (P = 0.001). The number-needed-to-treat was 3.27 for GSS and 3.59 for the APS report. Kaplan-Meier analysis revealed a mean response time of 4-5 weeks for active treatment and more than 8 weeks for placebo (P < 0.0001). Treatment of IBS with the bacterial lysate ProSymbioflor is effective and superior to placebo in reducing typical symptoms of IBS patients seen by general practitioners.

[The next consensus for the irritable bowel syndrome has to be interdisciplinary]

The publication of the Rome III consensus on functional bowel disorders one year ago has raised the question of whether a revision of the 1999 Celle consensus on the irritable bowel syndrome is necessary and who should be involved in this consensus. Therefore, the this review article attempts to reconstruct the history of the Rome criteria (and its predecessor, the Manning criteria) and contrasts this with the parallel history of the DSM/ICD classification in primary care and psychiatry/psychosomatics. The formulation of a common consensus between all medical societies (primary care, gastroenterology/neurogastroenterology, psychiatry/psychosomatics) is proposed instead of another consensus of gastroenterologists alone, in order to avoid the tendency--at both national and international levels--towards isolation between the medical subspecialties.

Digestive und prädigestive Funktionen bei Patienten mit Essstörungen

Patients with eating disorders (anorexia nervosa, AN; bulimia nervosa, BN) frequently exhibit gastrointestinal symptoms and altered gastrointestinal functions, especially delayed gastric emptying. These symptoms are regarded as secondary to the disordered eating behaviour, vomiting or laxative misuse. They often improve during successful therapy. There are, however, studies showing that in addition predigestive functions (smell, taste, cephalic phase of digestion) and the hormonal regulation of digestion may be changed in eating disorders. This underlines the possibility that, in a subpopulation of patients with AN and BN, the disturbed digestive and predigestive functions may be involved in the pathogenesis of the eating disorders. The current literature is analysed and summarised in this context.

Validation of the Addenbrooke's cognitive examination for detecting early Alzheimer's disease and mild vascular dementia in a German population

We assessed the diagnostic accuracy of the German version of the Addenbrooke's Cognitive Examination (ACE) in identifying early Alzheimer's disease (AD) and mild vascular dementia (VaD) in comparison with the conventional Mini-Mental State Examination (MMSE). The study refers to 50 patients with mild dementia of AD, 26 patients with mild dementia of vascular etiology and to 54 cognitively normal subjects. The ACE and MMSE were validated against an expert diagnosis based on a comprehensive diagnostic workup. Statistical analysis was performed using the receiver operator characteristics method. The optimal cut-off score for the ACE for detecting dementia in patients with early AD was 85/86, which had a sensitivity of 93% and a specificity of 86%. The optimal cut-off for the ACE for the identification of dementia in patients with mild VaD was also 85/86 and it had a sensitivity of 93% and a specificity of 100%. The kappa values imply a substantial agreement between the diagnoses made by the ACE and the MMSE. The German version of the ACE is a short and practical but accurate test battery for the identification of AD and VaD, assessing a broad range of cognitive functions and providing a wide profile of cognitive functions/dysfunctions.

Familientherapie bei Ess-Störungen

Die Familien von Patientinnen mit Ess-Störungen wie Anorexia nervosa (AN) und Bulimia nervosa (BN) sind durch die Erkrankung hohen emotionalen Belastungen ausgesetzt und zeichnen sich zudem häufig durch auffällige Familienstrukturen und -interaktionen aus. Daher spielt in der Diagnostik und Therapie von Ess-Störungen der Einbezug von Familienangehörigen der Patientinnen eine wichtige Rolle, deren Stellenwert zunehmend als wissenschaftlich gesichert gelten kann. Ganz besondere Bedeutung kommt dabei dem ärztlichen «Aufklärungsgespräch» mit Eltern und Patientinnen im primärärztlichen Kontext zum Aufbau der Therapiemotivation zu. Hierzu sollte der Behandler über Basiskenntnisse der Gesprächsführung mit Familien verfügen, wie sie in diesem Beitrag dargestellt werden. Das im weiteren therapeutischen Prozess angewendete Spektrum von Familieninterventionen reicht von edukativen und supportiven Maßnahmen bis zur Familientherapie im engeren Sinne, die ambulant oder im Rahmen einer stationären Therapie von Fachpsychotherapeuten durchgeführt wird.

Mitogen stimulation cooperates with telomere shortening to activate DNA damage responses and senescence signaling

Replicative senescence is induced by critical telomere shortening and limits the proliferation of primary cells to a finite number of divisions. To characterize the activity status of the replicative senescence program in the context of cell cycle activity, we analyzed the senescence phenotypes and signaling pathways in quiescent and growth-stimulated primary human fibroblasts in vitro and liver cells in vivo. This study shows that replicative senescence signaling operates at a low level in cells with shortened telomeres but becomes fully activated when cells are stimulated to enter the cell cycle. This study also shows that the dysfunctional telomeres and nontelomeric DNA lesions in senescent cells do not elicit a DNA damage signal unless the cells are induced to enter the cell cycle by mitogen stimulation. The amplification of senescence signaling and DNA damage responses by mitogen stimulation in cells with shortened telomeres is mediated in part through the MEK/mitogen-activated protein kinase pathway. These findings have implications for the further understanding of replicative senescence and analysis of its role in vivo.

Distribution of [3H]MK-801, [3H]AMPA and [3H]Kainate binding sites in rat hippocampal long-term slice cultures isolated from external afferents

The distribution of ionotropic glutamate receptors in transverse hippocampal sections and along the septotemporal hippocampal axis can be correlated to hippocampal connectivity, in particular to area- and layer-specific termination zones of afferents. However, in isolated organotypic hippocampal slice cultures developing without extrinsic afferent input no systematic studies exist about the distribution of glutamate receptors. In the present study we used receptor autoradiography to examine [3H]MK-801, [3H]AMPA and [3H]Kainate binding sites in hippocampal slice cultures prepared from 6-day-old rats. After 24 days in vitro layer-specific concentrations of [3H]MK-801, [3H]AMPA and [3H]Kainate binding sites were compared to age-matched hippocampi in situ (P30 rats). An obvious difference between hippocampal slice cultures and hippocampi in situ was a changed distribution of binding sites among the hippocampal areas showing a relative increase of [3H]MK-801 and [3H]AMPA binding sites in CA3 as compared to CA1 and to the dentate gyrus in the cultures. In CA1, however, the relative layer-specific distributions of [3H]MK-801 and [3H]AMPA binding sites were identical in hippocampal slice cultures and in hippocampi in situ. Interestingly, layer-specific binding of [3H]Kainate in the cultures exceeded that in the hippocampi in situ 3-5 times. Moreover, in the cultures the binding of the three ligands varied systematically showing gradients along the "superficiomembranal" axis. Cultures taken from different positions along the hippocampal axis differed with respect to concentrations of [3H]MK-801 and [3H]Kainate binding sites, but not of [3H]AMPA binding sites. The results suggest a massive sprouting and reorganisation of intrinsic projections in long-term hippocampal slice cultures.

Inositol 1,4,5-trisphosphate synthesis in mononuclear white blood cells of malignant hyperthermia-susceptible and normal human beings, following in vitro exposure to halothane, caffeine and ryanodine

Despite a plethora of findings associated with the pathophysiology of malignant hyperthermia (MH), the in vitro contracture test (IVCT) is the only reliable test for diagnosis of this heterogeneous syndrome in man. An increase of 1,4,5-IP3 (inositol 1,4,5-trisphosphate), a second messenger involved in cellular calcium homeostasis, has been observed in muscle tissue of MH susceptible (MHS) patients. The aim of this study was to evaluate if the known differences of 1,4,5-IP3 content in muscle tissue might be reproduced in mononucleated white blood cells (MWBCs). Subsequently, MWBCs of 23 healthy controls and 12 patients with a clinical suspicion for MH disposition were isolated and screened for 1,4,5-IP3 content. An IVCT according to the protocol of the European Malignant Hyperpyrexia Group (EMHG) was performed on muscle specimens of 12 patients. Eight MHN and four MHS individuals were diagnosed. Additionally, 1,4,5-IP3 synthesis in MWBCs was detected following in vitro exposure to IVCT test substances halothane (2%), caffeine (1-30mM), and ryanodine (1-5 microM). A broad inter-individual variability of 1,4,5-IP3 content was observed in MWBCs of all volunteers, but no differences were detected between MHS and MHN individuals. These findings are in strong contrast to those observed in muscle tissue. In vitro exposure of isolated MWBCs to halothane, caffeine and ryanodine yielded no statistically significant differences between groups. A time- and concentration-dependent increase in cellular 1,4,5-IP3 content could be induced in some but not all individuals of both groups. Since no correlation was obtained between induction of 1,4,5-IP3-synthesis following in vitro exposure of MWBCs to MH test substances and MH disposition, this study was terminated. We conclude from our data that the detection of 1,4,5-IP3 synthesis in MWBCs is not suitable for diagnosis of MH disposition. It remains questionable whether an altered 1,4,5-IP3 metabolism in MWBCs is involved in pathologic cascades of MH. Therefore, other cell tissues should be evaluated in further studies to clarify the role of the 1,4,5-IP3 metabolism in MH.

Immunohistochemical detection of induced expression of wild-type p53 tumor suppressor protein in the livers of rats treated with diethylnitrosamine

Paraffin sections of formalin-perfused rat livers were stained immunohistochemically for p53. In livers from untreated rats, no p53 expression was observed. p53 expression was induced in a response to treatment with diethylnitrosamine 24 h prior to sacrifice. Staining for p53 was localized in the nucleus of perivenous hepatocytes. In serial sections p53-immunopositive areas were found to co-localize with increased expression of TUNEL-positive cells. Without formalin perfusion, the staining for p53 was uneven and often barely detectable. Perfusion with saline prior to formalin resulted in a rapid decrease in the detectability of p53, indicating rapid degradation of this protein under these conditions. We conclude that rapid fixation by formalin perfusion increases the detectability of p53 by immunohistochemical staining. This provides a convenient procedure for studying the response of wild-type p53 in rodent liver. This procedure is also suitable for in situ investigations on the degradation of p53 protein stabilized by DNA damage.

Septotemporal distribution of [3H]MK-801, [3H]AMPA and [3H]Kainate binding sites in the rat hippocampus

The distribution of glutamate receptors in transverse hippocampal sections has been well investigated. However, in spite of the known septotemporal gradients of hippocampal connectivity no systematic studies exist about the distribution of glutamate receptors along the septotemporal (longitudinal) hippocampal axis. Therefore, in the present study this issue was investigated using receptor autoradiography for the [3H]MK-801, [3H]AMPA and [3H]Kainate binding sites. Hippocampi from 30-day-old rats were sectioned perpendicularly to their longitudinal axis, yielding a total of 25-30 equidistantly spaced autoradiographs for each hippocampus. For each section layer-specific concentrations of binding sites were calculated by the aid of a computerized image analysing system. The dependency of concentrations of binding sites on the septotemporal position was evaluated by regression analysis. Gradients of binding were confined to distinct hippocampal layers. Significant septotemporal gradients of [3H]MK-801 binding were observed in selected layers of CA1 and the dentate gyrus, a septal to temporal decrease of binding in the oriens and radiatum layers of CA1 being most prominent. For [3H]AMPA, significant septotemporal gradients of binding were restricted to layers of CA3, CA4 and the dentate gyrus, with values generally increasing from septal to temporal levels. The observed septotemporal gradients possibly reflect functional segregations along the longitudinal hippocampal axis and could be important for the comparability of ligand binding studies using transverse hippocampal sections or hippocampal slice cultures.

Telomeres in the haemopoietic system

The limited life span of most blood cells requires the continuous production of cells, which in adults exceeds 10(12) cells/day. This impressive production of cells (approximately 4 x 10(16) cells over a lifetime) is achieved by the proliferation and differentiation of committed progenitor cells, which themselves are derived from a population of pluripotent stem cells with self-renewal potential. Paradoxically, the large majority of stem cells in adult bone marrow are quiescent cells. One possibility is that stem cells, like other somatic cells, have only a limited replicative potential (< 100 divisions). This hypothesis is supported by two key observations and the consideration that, in theory, 55 divisions can yield 4 x 10(16) cells. First, it was shown that 'candidate' stem cells purified from fetal and adult tissue showed dramatic functional differences in turn-over time and the ability to produce cells with stem cell properties, Second, these functional differences were found to correlate with a measurable loss of telomere repeats despite the presence of low but readily detectable levels of telomerase in all purified cell fractions. In order to address questions about the role of telomeres in normal and malignant haemopoiesis, we developed a quantitative fluorescence in situ hybridization technique. Here we review the characteristics of this novel tool to assess the number of telomere repeats at the end of individual chromosomes and provide an overview of recent observations.

Low expression of the WAF1/CIP1 gene product, p21, in enzyme-altered foci induced in rat liver by diethylnitrosamine or phenobarbital

The expression of the WAF1/CIP1 gene product, p21, in enzyme-altered foci (EAF) induced by diethylnitrosamine (DEN) and phenobarbital (PB) was examined. p21 expression in the nucleus of hepatocytes in EAF was decreased compared to surrounding tissue. Fifty-eight percent of all GST-P-positive EAF induced by DEN and 79% of the EAF induced by PB were p21-negative. The proportion of p21-negative EAF increased with the size of the foci and more than 90% of the largest EAF were p21-negative. p21 is a mediator of p53 signals leading to block of the cell cycle. In conjunction with previous data indicating that p53 is not induced in GST-P-positive hepatocytes isolated from EAF-bearing rats, the results of this study suggest a role for altered signaling in the G1-S check point in rat hepatocarcinogenesis.

Isolation of glutathione S-transferase P-positive hepatocytes from carcinogen treated rats by use of ethacrynic acid as selecting agent

Rat liver responds to carcinogen treatment with growth of glutathione S-transferase P (GST-P)-positive enzyme-altered foci. In this paper a method is described where GST-P-positive hepatocytes are isolated from carcinogen-treated rats. The method utilizes ethacrynic acid, which is a good substrate for GST-P, and which induces toxicity mainly in GST-P-negative cells. The toxicity results in a loss of attachment to collagen. The method gives a 70% pure population of GST-P-positive cells attached to collagen-coated plates. Use of additional markers supports the conclusion that the GST-P-positive cells were derived from foci. Isolated GST-P-positive hepatocytes spread out and formed primary cultures of normal appearance. It was also shown that they synthesized DNA and did not respond to transforming growth factor beta 1. It is concluded that isolated GST-P-positive hepatocytes can be used for studies on alterations in enzyme-altered foci that cannot be done with in situ immunohistochemistry or in situ hybridization.

Burkitt-like mutations in the c-myc gene locus in prolymphocytic leukemia

The c-myc oncogene recently shown to act as a transcription factor, is involved in cellular proliferation. Deregulation of this gene can be one step in malignant transformation. In Burkitt's lymphoma (BL) the c-myc gene is consistently involved in chromosomal translocations and the first exon of the gene has been found to be a frequent target of somatic mutations. These mutations are believed to interfere with normal transcriptional regulation of the gene. We demonstrate a case of the rare prolymphocytic leukemia (PLL), a variant of chronic lymphocytic leukemia (CLL), that shows multiple Burkitt-like mutations in the first exon of c-myc and one nonconservative point mutation in the coding exon 2. Cytogenetic analysis revealed involvement of both chromosomes 8 in chromosomal translocations. Both chromosomes 8 are broken at (q23), the c-myc gene locus. Since the patient's leukemia cells exhibited high expression levels of the mutated allele of the c-myc mRNA, the point mutations alone may have accounted for transcriptional deregulation.