Search

Reading academic material is required in virtually all university classrooms. As such, reading can present a challenge not only for reluctant or resistant students, but also for instructors who assume students have completed assigned reading before class, have understood the information, and retained it for subsequent classroom discussion. However, research has shown the majority of students do not complete the assigned reading. Rather than presenting original data, this paper re-frames pedagogical practices in family science courses using a dual-classroom model for students to engage in active learning through assigned reading. Four active reading strategies are outlined to maximize dual-classroom learning environments.

We have shown previously that prostaglandin E2 (PGE2) and prostaglandin I2 (PGI2) are each produced in an explant model of peripheral nerve injury. We report that IP prostanoid receptor mRNA and protein are present in primary rat Schwann cells. IP prostanoid receptor stimulation using prostacyclin produced an elevation in intracellular cyclic AMP concentration ([cAMP]i) in primary Schwann cells. Peak [cAMP]i was observed between 5–15 min of stimulation followed by a gradual recovery toward basal level. Phosphorylation of cyclic AMP-response element binding protein (CREB) on Ser 133 was also detected after IP prostanoid receptor stimulation and CREB phosphorylation was inhibited completely by the protein kinase A inhibitor, H-89. Intracellular calcium levels were not affected by IP prostanoid receptor stimulation. Unlike forskolin, IP prostanoid receptor stimulation did not significantly augment Schwann cell proliferation in response to growth factor treatment. However, IP prostanoid receptor stimulation increased the number of Schwann cells that were able to generate a calcium transient in response to P2 purinergic receptor activation. These findings suggest that signaling via the IP prostanoid receptor may by relevant to Schwann cell biology in vivo. V C 2007 Wiley-Liss, Inc. {

The growth factor receptor c-Kit has several well-characterized functions during the development of numerous cell types, including red blood cells, mast cells, and melanocytes. Its role in Schwann cells has been described in transformed cells derived from malignant peripheral nerve sheath tumors from patients with neurofibromatosis type 1 (NF1 MPNST; Badache et al. [1998] Oncogene 17:795-800). However, c-Kit functions have not been investigated in normal Schwann cells. We report here that neonatal rat Schwann cells express low c-Kit levels, whereas expression levels for c-Kit are high for Schwann cells derived from MPNST of NF1 patients. In addition, c-Kit expression is not detectable in normal adult human Schwann cells. Although the c-Kit ligand stem cell factor (SCF) induces the phosphorylation of protein kinase B (or Akt) and prevents apoptosis in Schwann cells, SCF has no effect on the proliferation or differentiation of Schwann cells.

The ability of an AEF (axolemma-enriched fraction) to influence the proliferation, survival and differentiation of OPC (oligodendrocyte progenitor cells) was evaluated. Following addition of AEF to cultured OPC, the AEF associated with the outer surface of OPC so that subsequent metabolic events were likely mediated by direct AEF-OPC contact. Addition of AEF to the cultured OPC resulted in a dose- and time-dependent increase in proliferation that was partially dependent on Akt (protein kinase B) and MAPK (mitogen-activated protein kinase) activation. The major mitogen in an AEF-SE (soluble 2.0 M NaCl extract of the AEF) was identified as aFGF (acidic fibroblast growth factor) and accounted for 50% of the mitogenicity. The remaining 50% of the mitogenicity had properties consistent with bFGF (basic fibroblast growth factor) but was not unequivocally identified. Under conditions that limit the survival of OPC in culture, AEF treatment prolonged the survival of the OPC. Antigenic and morphological examination of the AEF-treated OPC indicated that the AEF treatment helped the OPC survive in a more immature state. The potential downstream metabolic pathways potentially activated in OPC by AEF and the consequences of these activated pathways are discussed. The results of these studies are consistent with the view that direct contact of axons with OPC stimulates their proliferation and survival while preventing their differentiation.

Malignant peripheral nerve sheath tumors (MPNSTs) are characteristic of Neurofibromatosis type 1 (NF1), a human genetic disorder affecting approximately 1 in 3000 individuals. The absence of neurofibromin in Schwann cells results in hyperactivation of Ras, which contributes to Schwann cell hyperplasia. However, additional intracellular abnormalities in Schwann cells might contribute to the malignancy. We now report that cell lines derived from MPNSTs secrete elevated levels of prostaglandin E2 (PGE2), express higher levels of phosphorylated mitogen-activated protein kinase (MAPK), phosphorylated cytosolic phospholipase A2 (cPLA2) and cyclooxygenase 2 (COX-2) when compared to normal adult human Schwann cells (nhSCs). PCR analysis reveals that NF1 MPNST cell lines express mRNA for both EP2 and EP4 prostaglandin E2 receptors, whereas nhSCs express only the EP4 receptor. COX-2 inhibitors and PGE2 receptor antagonists decrease the proliferation of MPNST cell lines. These results indicate that prostaglandin metabolism is activated in MPNSTs and might contribute to tumor growth in NF1.

A new gas chromatography detector with selectivity for reduced sulfur compounds is described. The detector monitors chemiluminescence resulting from the reaction of the GC effluent with molecular fluorine at reduced pressures. The reaction of sulfur compounds with fluorine produces vibrationally excited HF whose emission is detected with a red-sensitive photomultiplier tube. Detection limits in the range of 24-260 pg of analyte were obtained for a variety of sulfides, disulfides, and mercaptans. The detector has a linear response to sulfur compounds over at least 3 orders of magnitude and a selectivity over normal hydrocarbons of greater than 10/sup 7/. Selectivities over a variety of other classes of organic compounds also are presented. 25 references, 6 figures, 3 tables.