1,841 research outputs found
Detection of complete and partial chromosome gains and losses by comparative genomic in situ hybridization
Comparative genomic in situ hybridization (CGH) provides a new possibility for searching genomes for imbalanced genetic material. Labeled genomic test DNA, prepared from clinical or tumor specimens, is mixed with differently labeled control DNA prepared from cells with normal chromosome complements. The mixed probe is used for chromosomal in situ suppression (CISS) hybridization to normal metaphase spreads (CGH-metaphase spreads). Hybridized test and control DNA sequences are detected via different fluorochromes, e.g., fluorescein isothiocyanate (FITC) and tetraethylrhodamine isothiocyanate (TRITC). The ratios of FITC/TRITC fluorescence intensities for each chromosome or chromosome segment should then reflect its relative copy number in the test genome compared with the control genome, e.g., 0.5 for monosomies, 1 for disomies, 1.5 for trisomies, etc. Initially, model experiments were designed to test the accuracy of fluorescence ratio measurements on single chromosomes. DNAs from up to five human chromosome-specific plasmid libraries were labeled with biotin and digoxigenin in different hapten proportions. Probe mixtures were used for CISS hybridization to normal human metaphase spreads and detected with FITC and TRITC. An epifluorescence microscope equipped with a cooled charge coupled device (CCD) camera was used for image acquisition. Procedures for fluorescence ratio measurements were developed on the basis of commercial image analysis software. For hapten ratios 4/1, 1/1 and 1/4, fluorescence ratio values measured for individual chromosomes could be used as a single reliable parameter for chromosome identification. Our findings indicate (1) a tight correlation of fluorescence ratio values with hapten ratios, and (2) the potential of fluorescence ratio measurements for multiple color chromosome painting. Subsequently, genomic test DNAs, prepared from a patient with Down syndrome, from blood of a patient with Tcell prolymphocytic leukemia, and from cultured cells of a renal papillary carcinoma cell line, were applied in CGH experiments. As expected, significant differences in the fluorescence ratios could be measured for chromosome types present in different copy numbers in these test genomes, including a trisomy of chromosome 21, the smallest autosome of the human complement. In addition, chromosome material involved in partial gains and losses of the different tumors could be mapped to their normal chromosome counterparts in CGH-metaphase spreads. An alternative and simpler evaluation procedure based on visual inspection of CCD images of CGH-metaphase spreads also yielded consistent results from several independent observers. Pitfalls, methodological improvements, and potential applications of CGH analyses are discussed
Molecular cytogenetic characterization of a critical region in bands 7q35-q36 commonly deleted in malignant myeloid disorders
Loss of chromosome 7 (-7) or deletion of the long arm (7q-) are recurring chromosome abnormalities in myeloid leukemias. The association of - 7/7q- with myeloid leukemia suggests that these regions contain novel tumor suppressor gene(s), whose loss of function contribute to leukemic transformation or tumor progression. Based on chromosome banding analysis, two critical regions have been identified, one in band q22 and another in bands q32-q35. Presently there are no data available on the molecular delineation of the distal critical region. In this study we analyzed bone marrow and blood samples from 13 patients with myeloid leukemia (de novo myelodysplastic syndrome [MDS], n=3; de novo acute myeloid leukemia [AML], n=9; therapy-related (t-) AML, n=1) which, on chromosome banding analysis, exhibited deletions (n=12) or in one case a balanced translocation involving bands 7q31-qter using fluorescence in situ hybridization (FISH). As probes we used representative clones from a contig map of yeast artificial chromosome (YAC) clones that spans chromosome bands 7q31.1-qter. In the 12 cases with loss of 7q material, we identified a commonly deleted region of approximately 4 to 5 megabasepairs in size encompassing the distal part of 7q35 and the proximal part of 7q36. Furthermore, the breakpoint of the reciprocal translocation from the patient with t-AML was localized to a 1,300-kb sized YAC clone that maps to the proximal boundary of the commonly deleted region. Interestingly, in this case both homologs of chromosome 7 were affected: one was lost (-7) and the second exhibited the t(7q35). The identification and delineation of translocation and deletion breakpoints provides the first step toward the identification of the gene(s) involved in the pathogenesis of 7q35-q36 aberrations in myeloid disorders.link_to_OA_fulltex
Phase I trial of volasertib, a Polo-like kinase inhibitor, in Japanese patients with acute myeloid leukemia
This phase I trial conducted in Japanese patients with acute myeloid leukemia evaluated the safety, maximum tolerated dose and pharmacokinetics of volasertib (BI 6727), a selective Polo-like kinase inhibitor. The primary endpoints were the maximum tolerated dose of volasertib and the incidence of dose-limiting toxicities. Secondary endpoints were best response and remission duration. Other endpoints included safety and pharmacokinetics. Patients who were ineligible for standard induction therapy or with relapsed or refractory disease received volasertib monotherapy as a 2-h infusion on days 1 and 15 of a 28-day cycle, with dose escalation following a 3 + 3 design. A total of 19 patients were treated with three volasertib doses: 350, 400 and 450 mg. One patient receiving volasertib 450 mg reported a dose-limiting toxicity of grade 4 abnormal liver function test and 450 mg was determined as the maximum tolerated dose. The most frequently reported adverse events were febrile neutropenia (78.9%), decreased appetite (42.1%), nausea and rash (36.8% each), and sepsis, fatigue, hypokalemia, stomatitis and epistaxis (26.3% each). Best responses were complete remission (n = 3), complete remission with incomplete blood count recovery (n = 3) and partial remission (n = 1). The median remission duration of the six patients with complete remission or complete remission with incomplete blood count recovery was 85 days (range 56-358). Volasertib exhibited multi-compartmental pharmacokinetic behavior with a fast distribution after the end of infusion followed by slower elimination phases. Volasertib monotherapy was clinically manageable with acceptable adverse events and anti-leukemic activity. Plasma concentration of volasertib
Stochastic modeling of cargo transport by teams of molecular motors
Many different types of cellular cargos are transported bidirectionally along
microtubules by teams of molecular motors. The motion of this cargo-motors
system has been experimentally characterized in vivo as processive with rather
persistent directionality. Different theoretical approaches have been suggested
in order to explore the origin of this kind of motion. An effective theoretical
approach, introduced by M\"uller et al., describes the cargo dynamics as a
tug-of-war between different kinds of motors. An alternative approach has been
suggested recently by Kunwar et al., who considered the coupling between motor
and cargo in more detail. Based on this framework we introduce a model
considering single motor positions which we propagate in continuous time.
Furthermore, we analyze the possible influence of the discrete time update
schemes used in previous publications on the system's dynamic.Comment: Cenference proceedings - Traffic and Granular Flow 1
Interpretation des Verhaltens schizophren erkrankter Söhne durch ihre Eltern
In Abgrenzung zu AnsĂ€tzen der Psychoanalyse, der Sozialpsychiatrie und der psychiatrischen Soziologie wird bei dem vorgestellten Ansatz davon ausgegangen, daĂ im Zusammenleben mit schizophren Erkrankten die Beziehungen innerhalb der Familiengruppe starken Belastungen unterworfen sind und Anpassungsleistungen von den Einzelnen gefordert werden. Damit stehen subjektive Erlebnis-, Wahrnehmungs- und Verarbeitungsformen der Angehörigen sowie die aus der Konfrontation mit dem Kranken resultierende Interaktions- und Konfliktdynamik in der Familiengruppe im Mittelpunkt der Untersuchung. Die Exploration erfolgte in einem GruppengesprĂ€ch mit den Elternpaaren von vier schizphren erkrankten jungen MĂ€nnern im Alter von 18 bis 22 Jahren. Die vorliegende Arbeit basiert auf der systematischen qualitativen Analyse des Inhalts von 15 Gruppensitzungen von ca. 90 Minuten Dauer, die auf spĂ€ter transkribierten TonbĂ€ndern dokumentiert wurden. Der Beitrag konzentriert sich auf die Darstellung der Wahrnehmung belastender Verhaltensweisen durch die Eltern und auf deren Interpretationsversuche als handlungsleitende Orientierungen fĂŒr die dann jeweils gewĂ€hlten Kontrolltechniken und BewĂ€ltigungsstrategien. Die von den Eltern wahrgenommenen problematischen Verhaltensweisen der Söhne werden in vier Bereiche eingeordnet: Neigung zu InaktivitĂ€t, Verwahrlosung, fehlende emotionale Bezogenheit und Konstanz, IrrationalitĂ€t des Denkens und Planens. Es wird ermittelt, daĂ die Interpretationsmuster der Angehörigen vor allem dazu dienen, die eigene Angst und Verunsicherung zu reduzieren. Unterschiede bei den Eltern werden dahingehend herausgearbeitet, daĂ VĂ€ter die Krankheit als DissozialitĂ€t interpretieren, die MĂŒtter als Problemverhalten im Rahmen einer ausgeweiteten NormalitĂ€t. Belegt werden die Ergebnisse anhand von Ausschnitten aus den Tonbandprotokollen. (RW
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