Localization of postresection EGF receptor expression using laser capture microdissection

Background/Purpose: Epidermal growth factor (EGF) and its receptor (EGFR) are key components in the genesis of adaptation after small bowel resection (SBR). Within intestinal homogenates, EGFR expression is increased after SBR; however, the exact cells responsible for altered EGFR expression are unknown. In this study, laser capture microdissection (LCM) microscopy was used to elucidate the specific cellular compartment(s) responsible for postresection changes in EGFR expression. Methods: Male ICR mice underwent a 50% proximal SBR or sham operation. After 3 days, frozen sections were taken from the remnant ileum. Individual cells from villi, crypt, muscularis, and mesenchymal compartments were isolated by LCM. EGFR mRNA expression for each cell compartment was quantified using real-time polymerase chain reaction (PCR). Results: EGFR expression was increased after SBR within the crypt (2-fold) and muscularis compartments (3-fold). There were no changes detected after SBR in the villus tips or mesenchymal compartments. Conclusions: Increased expression of EGFR in crypts directly correlates with the zone of cell proliferation and supports the hypothesis that EGFR signaling is crucial for the mitogenic stimulus for adaptation. The finding of increased EGFR expression in the muscular compartment is novel and may implicate a role for EGFR as a mediator of the muscular hyperplasia seen after massive SBR. J Pediatr Surg 38:440-445.     

Differential connexin expression,gap junction intercellular coupling,and hemichannel formation in NT2/D1 human neural progenitors and terminally differentiated hNT neurons

Connexin-mediated gap junctions and open hemichannels in nonjunctional membranes represent two biologically relevant mechanisms by which neural progenitors can coordinate their response to changes in the extracellular environment. NT2/D1 cells are a teratocarcinoma progenitor line that can be induced to differentiate terminally into functional hNT neurons and NT-G nonneuronal cells. Clinical transplants of hNT neurons and experimental grafts of NT2/D1 progenitors or hNT neurons have been used in cell-replacement therapy in vivo. Previous studies have shown that NT2/D1 cells express connexin 43 (Cx43) and that NT2/D1 progenitors are capable of dye transfer. To determine whether NT2/D1 progenitors and differentiated hNT cultures express other connexins, Cx26, Cx30, Cx32, Cx36, Cx37, Cx43, and Cx46.6 mRNA and protein were analyzed. NT2/D1 progenitors express Cx30, Cx36, Cx37, and Cx43. hNT/NT-G cultures express Cx36, Cx37, and de novo Cx46.6. Cx26 and Cx32 were not expressed in NT2/D1 or hNT/NT-G cells. NT2/D1 progenitors formed functional gap junctions as assessed by dye coupling as well as open hemichannels in nonjunctional membranes as assessed by dye-uptake studies. Dye coupling was inhibited by the gap junction blocker 18alpha-glycyrrhetinic acid. Hemichannel activity was inhibited by the dual-specificity chloride channel/connexin hemichannel inhibitor flufenamic acid but not by the chloride channel inhibitor 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid. Both dye coupling and dye uptake were substantially reduced following differentiation of NT2/D1 progenitors. We conclude that the pattern of connexin expression in NT2/D1 cells changes over the course of differentiation corresponding with a reduction in biochemical coupling and hemichannel activity in differentiated cells.     

Intelligibility of sentences recorded from the uterus of a pregnant ewe and from the fetal inner ear

The intelligibility of sentences recorded from the uterus of a pregnant ewe and from the near-term fetal sheep inner ear was judged by 30 listeners. Sentences were presented to the ewe at 95 and 105 dB SPL while sequential recordings of sound with a hydrophone and a cochlear microphonic (CM) with electrodes were made. Recordings were randomized and presented to listeners to judge the intelligibility of sentences processed through the ewe and fetal inner ear. Intelligibility scores were nearly 99% for air and uterus conditions, dropped to 73% for CM ex utero and to 41% for CM in utero. Results indicated that filtering provided by the tissues and fluids of the maternal abdomen did not affect sentence intelligibility significantly, but the filtering effects as the signal passed into the fetal inner ear resulted in much poorer intelligibility.     

Both positive and negative beliefs are important in patients with spine pain: findings from the Occupational and Industrial Orthopaedic Center registry

Background Context

Negative beliefs are known to influence treatment outcome in patients with spine pain (SP). The impact of positive beliefs is less clear.

Removal of prion challenge from an immune globulin preparation by use of a size-exclusion filter

BACKGROUND: A size-exclusion filter (Viresolve 180, Millipore Corp.) was tested for its ability to remove transmissible spongiform encephalopathies prion protein from an immune globulin preparation during ultrafiltration. STUDY DESIGN AND METHODS: Hamster-adapted 263K scrapie brain homogenate (SBH) was spiked into Rh0(D) immune globulin (human) at 1 in 300 and 1 in 1000 dilutions. Before spiking, the SBH was treated with detergent, sonicated, and filtered through serial 0.45-, 0.22-, and 0.1-microm filters to present a rigorous filter challenge. Process variables were monitored throughout the ultrafiltration to ensure that the spiked material did not compromise the membrane flux. Removal of scrapie prion protein (PrP(Sc)) material was determined by use of a sensitive Western blot assay. RESULTS: The turbid SBH became completely translucent after sonication and passage through the 0.45-, 0.22-, and 0.1-microm filters. The filtration of the immune globulin containing PrP(Sc) material was more difficult to perform than was filtration of immune globulin spiked with the normal cellular isoform. Even during tangential flow filtration, the fibril material prevented the PrP(Sc)-spiked immune globulin from passing as readily through the filter. Western blot results indicated a removal of greater than or equal to 2.5 log PrP(Sc), while remaining within the normal filtration limits. CONCLUSIONS: The composition, physical condition, and the amount of SBH introduced have significant effects on the filtration of the immune globulin and the log removal values obtained. By use of a detergent-treated, sonicated, and filtered preparation of SBH, it was demonstrated that the Viresolve 180 effectively removes PrP(Sc) from the immune globulin.