Might intrinsic radioresistance of human tumour cells be induced by radiation?

Survival measurements were made on six human tumour cell lines in vitro after irradiation with single doses of X rays. Doses up to 5 Gy were used giving surviving fractions down to 20%, but the majority of the measurements were made at doses < 1 Gy. These six cell lines have very different intrinsic radiosensitivities: HT29, Be11, and RT112 are radioresistant with surviving fractions at 2 Gy (SF2) between 60 and 74%, while MeWo, SW48, and HX142 are radiosensitive (SF2 = 3-29%). For all the cell lines, response over the dose range 2-5 Gy showed a good fit to a Linear-Quadratic (LQ) model. However, HT29, Be11, and RT112 cells showed a significant increase in X-ray radiosensitivity at doses below < 1 Gy compared with the prediction extrapolated from a LQ model fitted to the data at higher doses. The LQ model also slightly underpredicted the effect of low-dose X rays in MeWo cells, but the response of SW48 and HX142 cells was well described by the LQ model at all doses, with no evidence of increased low-dose effectiveness. The most plausible explanation for this phenomenon is that it reflects an induced radioresistance so that low doses of X-rays in vitro are more effective per Gy than higher doses, because only at higher doses is there sufficient damage to trigger repair systems or other radioprotective mechanisms. It follows that variation in the amount of inducible radioresistance might explain, in part, differences in intrinsic radiosensitivity above > 1 Gy between cell lines: cells would be intrinsically radiosensitive because they have a diminished inducible response.     

Effects of reserpine on tissue calcium and contractility of rat and rabbit aorta

Possible effects of reserpine on disposition and availability of tissue calcium, stores for excitation-contraction coupling in isolated rat and rabbit aortae were examined. Contral 40Ca uptake, 45Ca washout, and contraction in Ca2+-free medium (Ca2+-free PSS) indicate species differences in binding or disposition, apparent functional importance, and differential use of tissue calcium by adrenaline (Epi) and high K+. Rat aortae, normally refractory to Epi or high K+ after 7 min in Ca2+-free PSS, can gain labile calcium after brief exposure to Ca2+-rich PSS which supports short-lived responses to high K+ in Ca2+-free PSS. Rabbit aortae contain calcium stores which may sustain either Epi or high-K+ responses as well as more tightly held (or sequestered) stores released by Epi for contraction. After reserpine, decreased 45Ca uptake in a kinetically defined "fast" compartment likely to include membrane calcium could enhance availability of bound tissue as well as free Ca2+ in both species. Enhanced Epi response in Ca2+-free PSS is evidence of the former. Results suggest that increased availability of bound and possibly free calcium contribute to reserpine-induced supersensitivity, but supporting evidence will be required from tissue behavior after less rigorous treatment.     

Savannah: mobile gaming and learning?

This paper reports a study that attempts to explore how using mobile technologies in direct physical interaction with space and with other players can be combined with principles of engagement and self‐motivation to create a powerful and engaging learning experience. We developed a mobile gaming experience designed to encourage the development of children's conceptual understanding of animal behaviour. Ten children (five boys and five girls) aged between 11 and 12 years played and explored the game. The findings from this study offer interesting insights into the extent to which mobile gaming might be employed as a tool for supporting learning. It also highlights a number of major challenges that this format raises for the organisation of learning within schools and the design of such resources.     

Structure of Anxiety and Depression in Urban Youth: An Examination of the Tripartite Model.

In this study, the authors examined the validity of the tripartite model of anxiety and depression (L. A. Clark & D. Watson, 1991) in a community epidemiological sample of 467 urban African American youth. Participants completed the Baltimore How I Feel (N. S. Ialongo, S. G. Kellam, & J. Poduska, 1999), a measure of anxiety and depressive symptoms, in Grades 6 and 9. Confirmatory factor analyses indicated that a 3-factor model representing the tripartite model fit the data well and better than competing models. Longitudinal confirmatory factor analysis revealed configural invariance of the tripartite factor structure. However, a predicted divergence among dimensions over time was not evidenced. High correlations among the tripartite dimensions suggest that anxiety and mood symptoms may not differentiate in urban youth. Results are discussed in terms of the ethnicity and urban context of this community sample. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development and Preliminary Validation of the Physiological Hyperarousal Scale for Children.

Considerable empirical support exists for the positive affect and negative affect components of the tripartite model of anxiety and depression proposed by L. A. Clark and D. Watson (1991); however, less attention has been paid to the physiological hyperarousal component of the model. The development of the Physiological Hyperarousal Scale for Children (PH-C; J. Laurent, S. J. Catanzaro, & T. E. Joiner Jr., 1995) is described. The psychometric properties of items are examined using students in Grades 6-12 (N = 398). Initial scale validation includes a joint factor analysis with the Positive and Negative Affect Scale for Children (PANAS-C; J. Laurent et al., 1999; J. Laurent, K. Potter, & S. J. Catanzaro, 1994). The relationship between the PH-C and existing measures that tap related constructs is examined. Together, the PH-C and PANAS-C provide a means to assess tripartite model constructs useful in differentiating anxiety and depression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Shyness and low social support as interactive diatheses, with loneliness as mediator: Testing an interpersonal-personality view of vulnerability to depressive symptoms.

Interpersonal approaches to depression are surveyed; it is suggested that interpersonal inhibition, as opposed to interpersonal excess, has been underemphasized as an antecedent of depression. It is proposed that shyness is a vulnerability factor for depressive symptoms in the absence but not in the presence of social support and that loneliness mediates the relation between shyness and depressive symptom increases. Undergraduates (N?=?172) reported on their levels of shyness, social support, loneliness, positive and negative affect, and depressive symptoms, and returned 5 weeks later to complete a similar set of assessments. Results supported hypotheses. Participants who were shy and unsupported were likely to experience increases in depressive symptoms and decreases in positive affect, whereas other students were not. This effect was partially mediated by increases in loneliness and was specific to depressive symptoms and low positive affect; it did not apply to negative affect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Search for sulfur (H2S) on Jupiter at millimeterwavelengths

The authors observed Jupiter at two wavelengths near 1.4 mm in an attempt to detect gaseous hydrogen sulfide (H₂S) or place new upper limits on its abundance in Jupiter's atmosphere. Although they were not successful in detecting H₂S, they report the first brightness temperature observations of Jupiter at 1.4 mm with a spectral resolution of approximately 1 GHz using Mars as the calibration standard. The methodology and results of a laboratory experiment in which the authors measured H₂S absorption at 1.4 mm in a simulated Jovian atmosphere (predominantly H₂ and He) are discussed. The results of the laboratory measurements are applied to a radiative transfer model, which is used to interpret the observations of Jupiter     

Is There a Window of Heightened Suicide Risk If Patients Gain Energy in the Context of Continued Depressive Symptoms?

The authors' purpose is to provide some empirical perspective on the important but understudied possibility that when people become more energetic in the context of continued depressive symptoms, suicide risk escalates. The authors studied 109 suicidal young adults; among those who initially reported substantial depression, a subgroup was identified whose energy was increasing in context of continued depressive symptoms. They were compared with others with regard to suicidality 1 month later. Results suggested that those who have incomplete remissions (of any sort) may be more ill to begin with, and this may account for higher suicide risk. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Strategic planning in a school of health related professions: organizational transformation for the future

The School of Health Related Professions (SHRP) at The University of Alabama at Birmingham (UAB) has been in existence for over a quarter of a century. During this time, it expanded and grew to offering 34 individual programs at the time of its silver anniversary. A concerted strategic planning process over two years has resulted in the School pursuing major organizational transformations to better align itself with the rest of the University's academic health center, to maximize its resources, and to refine its niche in academia. The strategic planning process used and major outcomes are described for the potential benefit of other schools of health related professions desiring to pursue introspection for future survival.