Tumour-cell susceptibility to cytotoxic or cytostatic effector cells in vitro and the regulation of tumour-cell growth in vivo.

Tumour-cell growth in lung nodules after i.v. transfer to sublethally irradiated mice has been followed after adoptive transfer of different populations of lymphoid cells. Spleen cells deliberately immunized in vitro and in vivo against stimulator cells bearing embryo-associated antigens and which are cytostatic in vitro for targets bearing such antigens, can diminish the number of lung nodules found after i.v. transfer. In contrast, cytotoxic (in vitro) spleen cells, while capable of diminishing local (s.c.) growth of tumour cells, cannot control systemic tumour growth. Within a given solid tumour mass, the subpopulations resistant to cytostatic effector cells in vitro are the ones most likely to produce lung colonies after adoptive transfer in vivo, though they show no more local (s.c.) growth than to cytostatic-sensitive cells in vivo

Inhibition of cell proliferation rather than of cell lysis as a measure of immune reactivity in embryo-antigen-challenged mice.

An assay system is described in which effector cells added along with suitable target cells inhibit, in a quantitative fashion, the subsequent uptake of 3H-thymidine by those target cells. Effector cells active in this assay, using embryonic fibroblast cells as targets, develop spontaneously in cultures of mouse lymphoid cells, but are apparently different from those described earlier by investigators of activity in cytotoxic assays. Further evidence is presented to show the development of spleen-derived effector cells with cytostatic activity (for embryonic fibroblast target cells) in mice during the course of normal pregnancy, or growth of spontaneously appearing mammary adenocarcinomas. Indeed, such effector cells can also be found within the growing solid mass itself. Different populations of tumour cells isolated from a solid tumour apparently differ in their susceptibility to growth inhibition by tumour-bearer-derived cytostatic effector cells, a phenomenon which may be related to metastatic spread of tumour cells

In conversation : Rod MacRae

French version available in IDRC Digital Library: Tête-à-tête avec Rod MacRa

Tête-à-tête avec Rod MacRae

Version anglaise disponible dans la Bibliothèque numérique du CRDI: In conversation : Rod MacRa

When expectancies harm comprehension: encoding flexibility in impression formation

We explored the possibility that the encoding flexibility processes postulated by Sherman and colleagues (1998) may also apply to intentional impression formation settings, even when cognitive resources are available to conceptually encode all of the behavioral information regardless of the relation of that information to the initial stereotypical expectancies. Three experiments offer evidence for the lower conceptual fluency for expectancy-incongruent behaviors, compared with congruent behaviors, as well as for the consequences of that difference for impression formation. Experiment 1 shows that incongruent behaviors are perceived as more difficult to understand in meaning. Experiment 2 links this lower conceptual fluency with a better discrimination of the specific trait implications of the behaviors. We further explore the role of conceptual encoding difficulty for developing personality impressions (Experiment 3). These studies reveal the implications of initial expectancies for the differential conceptual encoding of congruent and incongruent behaviors, even when the availability of cognitive resources is high, such as when forming an intentional impression about a person's personality. The link between this process and encoding the trait implications of behaviors may shed new light on impression formation processes and demand a revision of some of the assumptions that were made by the classical person memory model. We contend that behavior encoding in impression formation is likely to begin with default trait encoding but will be inhibited when the implications of the behavior conflict with previous trait expectancies (see also Wigboldus, Dijksterhuis, & van Knippenberg, 2003). (C) 2015 Elsevier Inc. All rights reserved.info:eu-repo/semantics/acceptedVersio

Slab Effects on Beam-Column Subassemblies - Beam Strength and Elongation Issues

This paper describes the effect of composite slabs in increasing beam strength and its implications for design. It also discusses the “beam-growth” phenomena, which can detrimentally influence the performance of a frame with reinforced concrete or precast concrete beams, and its impact on steel beams with RC slabs. From the subassembly testing conducted the slab increased the beam strength by around 40%. However the slab could not maintain strength at large drifts without degradation with transverse or longitudinal decking placed around the columns. This indicates that while transverse or longitudinal slabs should not be considered in design to size the beam, they should be considered in the beam overstrength calculations for the design of other members. Also, both rational considerations and experimental results 2 indicate that beam growth effects tend to be small for composite steel beams because the steel beams are able to yield in both tension and compression

Potential use of oxygen as a metabolic biosensor in combination with T2*-weighted MRI to define the ischemic penumbra

We describe a novel magnetic resonance imaging technique for detecting metabolism indirectly through changes in oxyhemoglobin:deoxyhemoglobin ratios and T2* signal change during ‘oxygen challenge’ (OC, 5 mins 100% O2). During OC, T2* increase reflects O2 binding to deoxyhemoglobin, which is formed when metabolizing tissues take up oxygen. Here OC has been applied to identify tissue metabolism within the ischemic brain. Permanent middle cerebral artery occlusion was induced in rats. In series 1 scanning (n=5), diffusion-weighted imaging (DWI) was performed, followed by echo-planar T2* acquired during OC and perfusion-weighted imaging (PWI, arterial spin labeling). Oxygen challenge induced a T2* signal increase of 1.8%, 3.7%, and 0.24% in the contralateral cortex, ipsilateral cortex within the PWI/DWI mismatch zone, and ischemic core, respectively. T2* and apparent diffusion coefficient (ADC) map coregistration revealed that the T2* signal increase extended into the ADC lesion (3.4%). In series 2 (n=5), FLASH T2* and ADC maps coregistered with histology revealed a T2* signal increase of 4.9% in the histologically defined border zone (55% normal neuronal morphology, located within the ADC lesion boundary) compared with a 0.7% increase in the cortical ischemic core (92% neuronal ischemic cell change, core ADC lesion). Oxygen challenge has potential clinical utility and, by distinguishing metabolically active and inactive tissues within hypoperfused regions, could provide a more precise assessment of penumbra

Bis(tetra­ethyl­ammonium) bis­(hydrogen l-tartrate) l-tartaric acid monohydrate

In the title compound, 2C8H20N+·2C4H5O6 −·C4H6O6·H2O, the presence of the two tetra­ethyl­ammonium cations is balanced by two hydrogen l-tartrate anions. Also present in the asymmetric unit are a mol­ecule of l-tartaric acid and a water mol­ecule. The various components are linked by O—H⋯O hydrogen bonds. In the crystal, two-dimensional networks are formed via O—H⋯O hydrogen bonds and C—H⋯O inter­actions involving the water mol­ecule, the hydrogen l-tartrate anions and the l-tartaric acid mol­ecules. These layers, which stack along [001], are separated by tetra­ethyl­ammonium cations. The latter are also involved in C—H⋯O inter­actions with the anions and the l-tartaric acid and water mol­ecules participating in the two-dimensional network

Dehydro­brachylaenolide: an eudesmane-type sesquiterpene lactone

The three-ring eudesmanolide, C15H16O3, is a natural product isolated from Dicoma anomala Sond. (Asteraceae). The compound contains an endo–exo cross conjugated methyl­enecyclo­hexenone ring with an envelope conformation trans-fused with cyclo­hexane and trans-annelated with an α-methyl­ene γ-lactone. The absolute structure was assigned by optical rotation measurements compared to those from the synthetic compound with known stereochemistry. The crystal packing is consolidated by C—H⋯O interactions