Patterns and dynamics of subventricular zone neuroblast migration in the ischemic striatum of the adult mouse.

The migratory behavior of neuroblasts after a stroke is poorly understood. Using time-lapse microscopy, we imaged migration of neuroblasts and cerebral vessels in living brain slices of adult doublecortin (DCX, a marker of neuroblasts) enhanced green fluorescent protein (eGFP) transgenic mice that were subjected to 7 days of stroke. Our results show that neuroblasts originating in the subventricular zone (SVZ) of adult mouse brain laterally migrated in chains or individually to reach the ischemic striatum.

The Notch pathway mediates expansion of a progenitor pool and neuronal differentiation in adult neural progenitor cells after stroke.

Molecular mechanisms by which stroke increases neurogenesis have not been fully investigated. Using neural progenitor cells isolated from the subventricular zone (SVZ) of the adult rat subjected to focal cerebral ischemia, we investigated the Notch pathway in regulating proliferation and differentiation of adult neural progenitor cells after stroke. During proliferation of neural progenitor cells, ischemic neural progenitor cells exhibited substantially increased levels of Notch, Notch intracellular domain (NICD), and hairy enhancer of split (Hes) 1, which was associated with a significant increase of proliferating cells.

Lengthening the G(1) phase of neural progenitor cells is concurrent with an increase of symmetric neuron generating division after stroke.

The proportion of neural progenitors that remain in (P fraction) and exit from (Q fraction) the cell cycle determines the degree of neurogenesis. Using S-phase labeling with 5-bromo-2'-deoxyuridine and a double nucleoside analog-labeling scheme, we measured the cell-cycle kinetics of neural progenitors and estimated the proportion of P and Q fractions in the subventricular zone (SVZ) of adult rats subjected to stroke. Stroke increased SVZ cell proliferation, starting 2 days, reaching a maximum 4 and 7 days after stroke.

The Sonic hedgehog pathway mediates carbamylated erythropoietin-enhanced proliferation and differentiation of adult neural progenitor cells.

Carbamylated erythropoietin (CEPO), a well characterized erythropoietin (EPO) derivative, does not bind to the classical EPO receptor and does not stimulate erythropoiesis. Using neural progenitor cells derived from the subventricular zone of the adult mouse, we investigated the effect of CEPO on neurogenesis and the associated signaling pathways in vitro. We found that CEPO significantly increased neural progenitor cell proliferation and promoted neural progenitor cell differentiation into neurons, which was associated with up-regulation of Sonic hedgehog (Shh), its receptor ptc, and mammalian achaete-scute homolog 1 (Mash1), a pro-neuron basic helix-loop-helix protein transcription factor.

Neuroblast division during migration toward the ischemic striatum: a study of dynamic migratory and proliferative characteristics of neuroblasts from the subventricular zone.

Ischemic stroke induces neurogenesis in the subventricular zone (SVZ), and newly generated neurons in the SVZ migrate toward the ischemic boundary. However, the characteristics of migrating SVZ cells have not been investigated after stroke. Using time-lapse imaging in both SVZ cells and organotypic brain slice cultures, we measured the dynamics of SVZ cell division and migration of adult rats subjected to stroke.

Stroke induces ependymal cell transformation into radial glia in the subventricular zone of the adult rodent brain.

Adult ependymal cells are postmitotic and highly differentiated. Radial glial cells are neurogenic precursors. Here, we show that stroke acutely stimulated adult ependymal cell proliferation, and dividing ependymal cells of the lateral ventricle had genotype, phenotype, and morphology of radial glial cells in the rat.

Matrix metalloproteinase 2 (MMP2) and MMP9 secreted by erythropoietin-activated endothelial cells promote neural progenitor cell migration.

We investigated the hypothesis that endothelial cells activated by erythropoietin (EPO) promote the migration of neuroblasts. This hypothesis is based on observations in vivo that treatment of focal cerebral ischemia with EPO enhances the migration of neuroblasts to the ischemic boundary, a site containing activated endothelial cells and angiogenic microvasculature. To model the microenvironment within the ischemic boundary zone, we used a coculture system of mouse brain endothelial cells (MBECs) and neural progenitor cells derived from the subventricular zone of the adult mouse.

Neurogenin 1 mediates erythropoietin enhanced differentiation of adult neural progenitor cells.

Proneuronal basic helix-loop-helix (bHLH) transcription factor, neurogenin 1 (Ngn1), regulates neuronal differentiation during development of the cerebral cortex. Akt mediates proneuronal bHLH protein function to promote neuronal differentiation. Here, we show that recombinant human erythropoietin (rhEPO) significantly increased Akt activity and Ngn1 mRNA levels in neural progenitor cells derived from the subventricular zone (SVZ) of adult rat, which was coincident with increases of neural progenitor cell proliferation, differentiation, and neurite outgrowth.

Oral manifestations of Ehlers-Danlos syndrome.

Ehlers-Danlos syndrome is a rare hereditary disease of the connective tissue which can present oral manifestations. A brief history of the disease is presented along with the epidemiology and characteristics of the 8 main phenotypes of the syndrome. The article also describes the case of a 12-year-old patient presenting with hypermobility of the temporo-mandibular joint and capillary fragility, and highlights the precautions to take when treating patients with this syndrome.

Phase III multicenter randomized trial of oxaliplatin added to chronomodulated fluorouracil-leucovorin as first-line treatment of metastatic colorectal cancer.

Purpose: To study how adding oxaliplatin (l-OHP) to chronomodulated fluorouracil (5-FU)-leucovorin (LV) affected the objective response rate, as first-line treatment of metastatic colorectal cancer.

Patients And Methods: Two hundred patients from 15 institutions in four countries were randomly assigned to receive a 5-day course of chronomodulated 5-FU and LV (700 and 300 mg/m(2)/d, respectively; peak delivery rate at 0400 hours) with or without l-OHP on the first day of each course (125 mg/m(2), as a 6-hour infusion). Each course was repeated every 21 days.

A multicenter evaluation of intensified, ambulatory, chronomodulated chemotherapy with oxaliplatin, 5-fluorouracil, and leucovorin as initial treatment of patients with metastatic colorectal carcinoma. International Organization for Cancer Chronotherapy.

Background: The combination of 5-fluorouracil (5-FU), leucovorin (LV), and oxaliplatin (I-OHP) was shown to be both more active against metastatic colorectal carcinoma and better tolerated if the drug delivery rate was chronomodulated according to circadian rhythms rather than constant. This allowed the authors to intensify the three-drug chronotherapy regimen and to assess its activity as the initial treatment of metastatic colorectal carcinoma patients in ten centers from four countries.

Methods: Patients with previously untreated and inoperable measurable metastases from colorectal carcinoma received a daily administration of chronomodulated 5-FU (700 mg/m2/day, peak delivery rate at 04:00 hours), LV (300 mg/m2/day, peak delivery rate at 04:00 hours), and 1-OHP (25 mg/m2/day, peak delivery rate at 16:00 hours) for 4 days every 14 days.