Activation-dependent redistribution of cellular components alters susceptibility of human neutrophils to cross-linking agents

Contrary to resting cells, neutrophils stimulated with concanavalin A resist inhibition by bifunctionalN-hydroxysuccinimide esters. Con A prestimulated, cross-linker-treated cells released superoxide upon restimulation with PMA but did not respond to chemotactic peptides. Although rates of PMA-elicited NADPH oxidase activity were lowered by the treatment, the activation parameters, namely lag times of the reaction, were not altered. The protection by Con A against blockade by cross-linkers developed concomitantly to the activation of NADPH oxidase and indicated redistribution of cross-linker-susceptible cellular components responsible for activation with PMA. The identity of these components is discussed.     

Concept mapping: an educational strategy for advancing nursing education

TOPIC: Application of concept mapping as a tool in nursing education. PURPOSE: To highlight the use of concept mapping as a method for advanced learning in nursing education. SOURCES OF INFORMATION: Literature from nursing and general education, instructor and student experiences, and opinions from using concept maps as a method of teaching/learning. CONCLUSIONS: Instructors and students reported satisfaction from use of concept maps in the educational process. Teaching with the aid of concept maps has been incorporated as an innovative and viable teaching method in nursing education.     

Effectiveness of home rehabilitation after stroke in Israel

On discharge from an acute general hospital after a stroke, 191 patients were in need of, and were appropriate for, multidisciplinary rehabilitation. One-hundred-and-one patients (52.4%) received it in a rehabilitation institution as inpatients (the institutional rehabilitation group (IR) group) and 91 patients received it at home (the home rehabilitation (HR) group). Patients in the HR group had their mobility, activities of daily living (ADL), range of movements, tonus, coordination and sensation determined on admission to home rehabilitation and on discharge from it, 6 weeks to 2 months later. This group contained more women and more patients able to walk with devices and who were partially independent in ADL. The IR group consisted of more men and more patients with diabetes and marked difficulties in ADL and ambulation. In both groups the Barthel index and the Frenchay activities index were determined 1 year after the stroke by way of a telephone interview and no meaningful differences were found between the two groups. IR was considerably more expensive than HR. In Israel there exists a subpopulation of acute stroke survivors in need of, and appropriate for, multidisciplinary rehabilitation that can be provided at home; such rehabilitation was found to be effective in the short and long term, as well as cost effective.     

Transformation mechanism of amorphous calcium carbonate into calcite in the sea urchin larval spicule

Sea urchin larval spicules transform amorphous calcium carbonate (ACC) into calcite single crystals. The mechanism of transformation is enigmatic: the transforming spicule displays both amorphous and crystalline properties, with no defined crystallization front. Here, we use X-ray photoelectron emission spectromicroscopy with probing size of 40–200 nm. We resolve 3 distinct mineral phases: An initial short-lived, presumably hydrated ACC phase, followed by an intermediate transient form of ACC, and finally the biogenic crystalline calcite phase. The amorphous and crystalline phases are juxtaposed, often appearing in adjacent sites at a scale of tens of nanometers. We propose that the amorphous-crystal transformation propagates in a tortuous path through preexisting 40- to 100-nm amorphous units, via a secondary nucleation mechanism.     

Blockage of VIP during mouse embryogenesis modifies adult behavior and results in permanent changes in brain chemistry

Vasoactive intestinal peptide (VIP) regulates growth and development during the early postimplantation period of mouse embryogenesis. Blockage of VIP with a VIP antagonist during this period results in growth restriction, microcephaly, and developmental delays. Similar treatment of neonatal rodents also causes developmental delays and impaired diurnal rhythms, and the adult brains of these animals exhibit neuronal dystrophy and increased VIP binding. These data suggest that blockage of VIP during the development of the nervous system can result in permanent changes to the brain. In the current study, pregnant mice were treated with a VIP antagonist during embryonic days 8 through 10. The adult male offspring were examined in tests of novelty, paired activity, and social recognition. Brain tissue was examined for several measures of chemistry and gene expression of VIP and related compounds. Glial cells from the cortex of freated newborn mice were plated with neurons and examined for VIP binding and their ability to enhance neuronal survival. Treated adult male mice exhibited increased anxiety-like behavior and deficits in social behavior. Brain tissue exhibited regionally specific changes in VIP chemistry and a trend toward increased gene expression of VIP and related compounds that reached statistical significance in the VIP receptor, VPAC-1, in the female cortex. When compared to control astrocytes, astrocytes from treated cerebral cortex produced further increases in neuronal survival with excess synaptic connections and reduced VIP binding. In conclusion, impaired VIP activity during mouse embryogenesis resulted in permanent changes to both adult brain chemistry/cell biology and behavior with aspects of autism-like social deficits.     

Antidepressants induce cellular insulin resistance by activation of IRS-1 kinases

Certain selective serotonin reuptake inhibitors (SSRIs) induce the clinical and biochemical manifestations of a metabolic syndrome by as yet unknown mechanism. Here we demonstrate that incubation (1 h) of rat hepatoma Fao cells with the SSRIs paroxetine and sertraline, but not with the atypical antipsychotic drug olanzapine, inhibited the insulin-stimulated Tyr phosphorylation of the insulin receptor substrate-1 (IRS-1) with half-maximal effects at approximately 10 microM. This inhibition correlated with a rapid phosphorylation and activation of a number of Ser/Thr IRS-1 kinases including JNK, S6K1, ERK and p38 MAPK, but not PKB (Akt). JNK appears as a key player activated by SSRIs because specific JNK inhibitors partially eliminated the effects of these drugs. The SSRIs induced the phosphorylation of IRS-1 on S307 and S408, which inhibits IRS-1 function and insulin signaling. These results implicate selected SSRIs as inhibitors of insulin signaling and as potential inducers of cellular insulin resistance.     

In vitro electrophysiological drug testing using human embryonic stem cell derived cardiomyocytes

Pro-arrhythmia (development of cardiac arrhythmias as a pharmacological side effect) has become the single most common cause of the withdrawal or restrictions of previously marketed drugs. The development of new medications, free from these side effects, is hampered by the lack of an in vitro assay for human cardiac tissue. We hypothesized that human embryonic stem cell-derived cardiomyocytes (hESC-CMs) assessed with a combination of single cell electrophysiology and microelectrode array (MEA) mapping can serve as a novel model for electrophysiological drug screening. Current-clamp studies revealed that E-4031 and Sotalol (IKr blockers) significantly increased hESC-CM's action potential duration and also induced after-depolarizations (the in vitro correlates of increased arrhythmogenic potential). Multicellular aggregates of hESC-CMs were then analyzed with the MEA technique. Application of class I (Quinidine, Procaineamide) and class III (Sotalol) antiarrhythmic agents, E-4031, and Cisapride (a noncardiogenic agent known to lengthen QT) resulted in dose-dependent prolongation of the corrected field potential duration (cFPD). We next utilized the MEA technique to also assess pharmacological effects on conduction. Activation maps demonstrated significant conduction slowing following administration of Na channel blockers (Quinidine and Propafenone) and of the gap junction blocker (1-heptanol). While most attention has been focused on the prospects of using hESC-derived cardiomyocytes for regenerative medicine, this study highlights the possible utilization of these unique cells also for cardiac electrophysiological studies, drug screening, and target validation.     

Allogeneic induced human FOXP3+IFN‐γ+ T cells exhibit selective suppressive capacity

Human induced CD4⁺CD25⁺ T cells have been shown to express FOXP3, similar to naturally occurring Treg cells (nTreg). However, the suppressive capacity of these cells is still under debate. The current study was designed to investigate functional characteristics of CD25⁺FOXP3⁺ derived from CD25^? T cells. Stimulation of CD25^? PBMC with allogeneic PBMC resulted in production of CD4⁺CD25^high T cells. This process was more rapid and prominent when highly mature DC were used for stimulation. The resultant CD4⁺CD25^high population concurrently exhibited regulatory markers FOXP3, CTLA‐4, GITR, and inflammatory cytokines IL‐2 and IFN‐γ. These human‐induced FOXP3⁺IFN‐γ⁺ T cells were shown, for the first time, to markedly inhibit alloreactive T‐cell expansion, similar to nTreg. However, in contrast to nTreg, the induced CD4⁺CD25⁺FOXP3⁺ cells did not suppress proliferation against a third party donor stimulus or CMV. This suggested that the cell population possessed a more selective suppressive capacity targeted against the original stimulus only. The induced human CD4⁺CD25⁺FOXP3⁺ subset derived from CD25^? T cells, while expressing inflammatory cytokines, exhibits a suppressive cell contact‐dependent effect, restricted against T cells responding to the original stimulus. Such unique properties suggest that these cells are potentially ideal for the use as post‐transplant GVH disease prophylaxis.