Repeated cisplatin treatment can lead to a multiresistant tumor cell population with stem cell features and sensitivity to 3-bromopyruvate

Cisplatin is used in treatment of several types of cancer, including epithelial ovarian carcinoma (EOC). In order to mimic clinical treatment and to investigate longterm effects of cisplatin in surviving cancer cells, two EOC cell lines were repeatedly treated with low doses. In the SKOV-3 cell line originating from malignant ascites, but not in A2780 cells from a primary tumor, this led to emergence of a stable population (SKOV-3-R) which in the absence of cisplatin showed increased motility, epithelial-mesenchymal transition (EMT) and expression of cancer stem cell markers CD117, CD44 and ALDH1. Accordingly, the cells formed self-renewing spheres in serum-free stem cell medium. Despite upregulation of mitochondrial mass and cytochrome c, and no upregulation of Bcl-2/Bcl-xL, SKOV-3-R were multiresistant to antineoplastic drugs. Cancer stem cells, or tumor-initiating cells (TICs) are highly chemoresistant and are believed to cause relapse into disseminated and resistant EOC. Our second aim was therefore to target resistance in these TIC-like cells. Resistance could be correlated with upregulation of hexokinase-II and VDAC, which are known to form a survival-promoting mitochondrial complex. The cells were thus sensitive to 3-bromopyruvate, which dissociates hexokinase-II from this complex, and were particularly sensitive to combination treatment with cisplatin at doses down to 0.1 x IC 50. 3-bromopyruvate might thus be of use in targeting the especially aggressive TIC populations.

A randomised controlled study of role play in a faculty development programme

BACKGROUND

The Stanford Faculty Development Center at Stanford University has developed a teaching improvement course for medical teachers that has been widely disseminated using a train-the-trainer model.

AIMS

This study was designed to investigate the relative impact of role playing as an instructional technique within that course for facilitating change in teaching behaviours.

METHOD

From January 2009 to April 2010, six faculty development courses were delivered at Uppsala University Hospital to 48 physicians from different departments. The standard course presentation includes a range of instructional methods including short lectures, small group discussion, review of video re-enactments, role-play exercises and personal goal setting. For this study, participants were randomised to participate in (1) a 'standard' course with role play or (2) an 'alternative' course with no role play. The effects of the course on teaching performance were assessed with retrospective pre- and post-course self-ratings of 29 specific teaching behaviours.

RESULTS

Self-assessment ratings indicated significantly greater positive changes in teaching behaviour among faculty who attended the standard course (with role play) as compared to those in the alternative course (p = 0.015).

CONCLUSIONS

This study validates the commonly held view that role play is a useful instructional method for improving teaching.

Understanding social collaboration between actors and technology in an automated and digitised deep mining environment

The purpose of this article is to develop knowledge and learning on the best way to automate organisational activities in deep mines that could lead to the creation of harmony between the human, technical and the social system, towards increased productivity. The findings showed that though the introduction of high-level technological tools in the work environment disrupted the social relations developed over time amongst the employees in most situations, the technological tools themselves became substitute social collaborative partners to the employees. It is concluded that, in developing a digitised mining production system, knowledge of the social collaboration between the humans (miners) and the technology they use for their work must be developed. By implication, knowledge of the human's subject-oriented and object-oriented activities should be considered as an important integral resource for developing a better technological, organisational and human interactive subsystem when designing the intelligent automation and digitisation systems for deep mines. STATEMENT OF RELEVANCE: This study focused on understanding the social collaboration between humans and the technologies they use to work in underground mines. The learning provides an added knowledge in designing technologies and work organisations that could better enhance the human-technology interactive and collaborative system in the automation and digitisation of underground mines.

No evidence for developmental plasticity of color patterns in response to rearing substrate in pygmy grasshoppers

Color polymorphisms in animals may result from genetic polymorphisms, developmental plasticity, or a combination where some phenotypic components are under strong genetic control and other aspects are influenced by developmental plasticity. Understanding how color polymorphisms evolve demands knowledge of how genetic and epigenetic environmental cues influence the development and phenotypic expression of organisms. Pygmy grasshoppers (Orthoptera, Tetrigidae) vary in color pattern within and among populations. Color morphs differ in morphology, behavior, and life history, suggesting that they represent alternative ecological strategies. Pygmy grasshoppers also show fire melanism, a rapid increase in the frequency of black and dark-colored phenotypes in populations inhabiting fire-ravaged areas. We examined the influence of plasticity on color polymorphism in the pygmy grasshopper Tetrix subulata (L., 1761) using a split-brood design. Individuals were experimentally raised in solitude on either crushed charcoal or white aquarium gravel. Our analyses uncovered no plasticity of either color pattern or overall darkness of coloration in response to rearing substrate. Instead, we find a strong resemblance between maternal and offspring color patterns. We conclude that pygmy grasshopper color morphs are strongly influenced by genetic cues or maternal effects, and that there is no evidence for developmental plasticity of coloration in response to rearing conditions in these insects.

Engineered disulfides improve mechanical properties of recombinant spider silk

Nature's high-performance polymer, spider silk, is composed of specific proteins, spidroins, which form solid fibers. So far, fibers made from recombinant spidroins have failed in replicating the extraordinary mechanical properties of the native material. A recombinant miniature spidroin consisting of four poly-Ala/Gly-rich tandem repeats and a nonrepetitive C-terminal domain (4RepCT) can be isolated in physiological buffers and undergoes self assembly into macrofibers. Herein, we have made a first attempt to improve the mechanical properties of 4RepCT fibers by selective introduction of AA --> CC mutations and by letting the fibers form under physiologically relevant redox conditions. Introduction of AA --> CC mutations in the first poly-Ala block in the miniature spidroin increases the stiffness and tensile strength without changes in ability to form fibers, or in fiber morphology. These improved mechanical properties correlate with degree of disulfide formation. AA --> CC mutations in the forth poly-Ala block, however, lead to premature aggregation of the protein, possibly due to disulfide bonding with a conserved Cys in the C-terminal domain. Replacement of this Cys with a Ser, lowers thermal stability but does not interfere with dimerization, fiber morphology or tensile strength. These results show that mutagenesis of 4RepCT can reveal spidroin structure-activity relationships and generate recombinant fibers with improved mechanical properties.

Clinical teaching improvement: The transportability of the Stanford Faculty Development Program

BACKGROUND

The Stanford Faculty Development Center (SFDC) at Stanford University developed a teaching improvement course for medical teachers that has been widely disseminated using a train-the-trainer model. We were curious to see if cultural factors might influence the applicability and impact of the course when delivered to non-American participants by a facilitator from that culture.

METHODS

A Swedish anaesthesiologist at Uppsala University Hospital, Sweden, was trained in October 2004 at Stanford University. From January 2005 to March 2007 he delivered five faculty development seminar series at Uppsala University Hospital to 40 physicians from different departments. Participants rated the usefulness of the seminar series and retrospective pre- and post-seminar ratings were used to assess effects on participants' teaching skills and behaviours.

RESULTS

Participants rated the seminars as highly useful (M = 4.8, SD = 0.4). Participants' ratings of their teaching ability indicated significant increases across a variety of clinical and non-clinical teaching settings (p < 0.001), and positive changes in teaching behaviours were found for all seven educational categories assessed (p < 0.001).

CONCLUSIONS

This faculty development model is highly transportable to medical teachers in Sweden, and capable of producing positive results, consistent with those found in the United States.

Preventing amyloid formation by catching unfolded transmembrane segments

A subset of protein misfolding diseases, including, for example, Alzheimer's disease, is associated with the formation of highly insoluble amyloid fibrils with a beta-sheet structure. The amyloidogenic human lung surfactant protein C (SP-C) is generated from SP-C precursor, which has a C-terminal domain (CTC) that prevents SP-C amyloid fibril formation. Analysis of the substrate specificity of CTC reveals that it binds to all amino acid residues that promote membrane insertion, provided that they are in a nonhelical conformation. In line with this unexpectedly general substrate specificity, the anti-amyloid function of CTC extends to a transmembrane segment other than that of (pro)SP-C, namely, the amyloid beta-peptide associated with Alzheimer's disease. These findings indicate that CTC is the first known chaperone to be directed towards nonhelical transmembrane segments and that it may be employed for the development of new diagnostics or anti-amyloid therapies.

Aberrant amino acid transport in fibroblasts from patients with bipolar disorder

Aberrant tyrosine transport is a repeated finding in fibroblasts from schizophrenic patients. The transport aberration could lead to disturbances in the dopaminergic and noradrenergic neurotransmitter systems. Tyrosine and tryptophan are the precursors of the neurotransmitters dopamine and serotonin. Disturbed dopaminergic, noradrenergic and serotoninergic systems are implicated as causes of bipolar disorder. Hence, the aim of this study was to explore whether patients with bipolar disorder have an aberrant transport of tyrosine and/or tryptophan. Fibroblast cell lines from patients with bipolar type-1 disorder (n=10) and healthy controls (n=10) were included in this study. All patients fulfilled the DSM-IV diagnostic criteria. The transport of amino acids across the cell membranes was measured by the cluster tray method. The kinetic parameters, maximal transport velocity (V(max)) and affinity constant (K(m)) were determined. A significantly lower V(max) for tyrosine (p=0.027) was found in patients with bipolar type-1 disorder in comparison to healthy controls. No significant differences in K(m) for tyrosine and in the kinetic parameters of tryptophan between patients with bipolar type-1 disorder and healthy controls were observed. The decreased tyrosine transport (low V(max)) found in this study may indicate less access of dopamine in the brain, resulting in disturbed dopaminergic and/or noradrenergic neurotransmission, that secondarily could lead to disturbances in other central neurotransmitter systems, such as the serotoninergic system. However, as sample size was small in this study and an age difference between patients and controls existed, the present findings should be considered as pilot data. Further studies with larger sample number are needed to elucidate the transport aberration and the significance of these findings.

Controlled polytypic and twin-plane superlattices in iii-v nanowires

Semiconductor nanowires show promise for use in nanoelectronics, fundamental electron transport studies, quantum optics and biological sensing. Such applications require a high degree of nanowire growth control, right down to the atomic level. However, many binary semiconductor nanowires exhibit a high density of randomly distributed twin defects and stacking faults, which results in an uncontrolled, or polytypic, crystal structure. Here, we demonstrate full control of the crystal structure of InAs nanowires by varying nanowire diameter and growth temperature. By selectively tuning the crystal structure, we fabricate highly reproducible polytypic and twin-plane superlattices within single nanowires. In addition to reducing defect densities, this level of control could lead to bandgap engineering and novel electronic behaviour.

Probing noise in flux qubits via macroscopic resonant tunneling

Macroscopic resonant tunneling between the two lowest lying states of a bistable rf SQUID is used to characterize noise in a flux qubit. Measurements of the incoherent decay rate as a function of flux bias revealed a Gaussian-shaped profile that is not peaked at the resonance point but is shifted to a bias at which the initial well is higher than the target well. The rms amplitude of the noise, which is proportional to the dephasing rate 1/tauphi, was observed to be weakly dependent on temperature below 70 mK. Analysis of these results indicates that the dominant source of low energy flux noise in this device is a quantum mechanical environment in thermal equilibrium.