191 ROBUST GENERATION OF NEURAL STEM CELLS FROM PIG INDUCED PLURIPOTENT STEM CELLS FOR TRANSLATIONAL NEURAL REGENERATIVE MEDICINE

The generation of pig induced pluripotent stem cells (iPSC) opened the possibility to evaluate autologous neural cell therapy as a viable option for human patients. However, it is necessary to demonstrate whether pig iPSC are capable of in vitro neural differentiation similar to human iPSC in order to perform in vitro and in vivo comparative studies. Multiple laboratories have generated pig iPSC that have been characterised using pluripotent markers such as SSEA4 and POU5F1. However, correlations of pluripotent marker expression profiles among iPSC lines and their neural differentiation potential has not been fully explored. Because neural rosettes (NR) are composed of neural stem cells, our goal was to demonstrate that NR from pig iPSC can be generated, isolated, and expanded in vitro from multiple porcine iPSC lines similar to human iPSC and that the level of pluripotency in the starting porcine iPSC population (POUF51 and SSEA4 expression) could influence NRs development. Three lines of pig iPSC L1, L2, and L3 were cultured on matrigel-coated plates in mTeSR1 medium (Stemcell Technologies Inc., Vancouver, BC, Canada) and passaged every 3 to 4 days. For neural induction (NI), pig iPSC were disaggregated using dispase and plated. After 24 h, cells were maintained in N2 media [77% DMEM/F12, 10 ng mL–1 bovine fibroblast growth factor (bFGF), and 1X N2] for 15 days. To evaluate the differentiation potential to neuron and glial cells, NR were isolated, expanded in vitro and cultured for three weeks in AB2 medium (AB2, 1X ANS, and 2 mM L-Glutamine). Immunostaining assays were performed to determine pluripotent (POU5F1 and SSEA4), tight junction (ZO1), neural epithelial (Pax6 and Sox1), neuron (Tuj1), astrocyte (GFAP), and oligodendrocyte (O4) marker expression. Line L2 (POU5F1high and SSEA4low) showed a high potential to form NR (6.3.5%, P < 0.05) in comparison to the other 2 lines L1 (POU5F1low and SSEA4low) and L3 (POU5F1low and SSEA4high) upon NI. The NR immunocytochemistry results from Line L2 showed the presence of Pax6+ and Sox1– NRs cells at day 9 post-neural induction and that ZO1 started to localise at the apical border of NRs. At day 13, NRs cells were Pax6+ and Sox1+, and ZO1 was localised to the lumen of NR. After isolation and culture in vitro, NR cells expressed transcription factors PLAGL1, DACH1, and OTX2 through 2 passages, but were not detected in later passages. However, rosette cytoarchitecture was present up until passage 7 and were still Pax6+/Sox1+. NRs at passage 2 were cryopreserved and upon thaw showed normal NR morphology and were Pax6+/Sox1+. To characterise the plasticity of NRs, cells were differentiated. Tuj1 expression was predominant after differentiation indicating a bias towards a neuron phenotype. These results demonstrate that L2 pig iPSC (POUF51high and SSEA4low) have a high potential to form NR and neural differentiation parallels human iPSC neurulation events. Porcine iPSC should be considered as a large animal model for determining the safety and efficacy of human iPSC neural cell therapies.

Oral glucose leads to a differential response in glucose, insulin, and GLP-1 in lean versus obese cats

The response to oral glucose was examined in 10 obese and 9 lean age-matched, neutered cats. In all cats, oral administration of 2g/kg glucose was followed by a prompt increase in glucose, insulin, and glucagon-like peptide (GLP)-1. There were significant differences between lean and obese cats in the areas under the curve for glucose, insulin, and GLP-1. However, the responses were variable, and a clear distinction between individual lean and obese cats was not possible. Therefore, this test cannot be recommended as a routine test to examine insulin resistance in individual cats as it is used in people. A further disadvantage for routine use is also the fact that this test requires gastric tubing for the correct administration of the glucose and associated tranquilization to minimize stress and that it was associated with development of diarrhea in 25% of the cats. GLP-1 concentrations were much lower in obese than lean cats. The low GLP-1 concentrations in obese cats might indicate a contribution of GLP-1 to the lower insulin sensitivity of obese cats, but this hypothesis needs to be further investigated.

Identification of CD66a and CD66b as the major galectin-3 receptor candidates in human neutrophils

The mammalian lectin galectin-3 is a potent stimulus of human neutrophils, provided that the receptor(s) for the lectin has been mobilized to the cell surface before activation. We have recently shown that the receptors for galectin-3 are stored in intracellular mobilizable granules. Here we show supportive evidence for this in that DMSO-differentiated (neutrophil-like) HL-60 cells, which lack gelatinase and specific granules, are nonresponsive when exposed to galectin-3. Neutrophil granules were subsequently used for isolation of galectin-3 receptors by affinity chromatography. Proteins eluted from a galectin-3-Sepharose column by lactose were analyzed on SDS-polyacrylamide gels and showed two major bands of 100 and 160 kDa and a minor band of 120 kDa. By immunoblotting, these proteins were shown to correspond to CD66a (160 kDa), CD66b (100 kDa), and lysosome-associated membrane glycoprotein-1 and -2 (Lamp-1 and -2; 120 kDa). The unresponsive HL-60 cells lacked the CD66 Ags but contained the Lamps, implying that neutrophil CD66a and/or CD66b may be the functional galectin-3 receptors. This conclusion was supported by the subcellular localization of the CD66 proteins to the gelatinase and specific granules in resting neutrophils.

Characterization of regions within the N-terminal 6-kilodalton domain of phytochrome A that modulate its biological activity

Phytochrome A (phyA) is a red/far-red (FR) light photoreceptor responsible for initiating numerous light-mediated plant growth and developmental responses, especially in FR light-enriched environments. We previously showed that the first 70 amino acids of the polypeptide contain at least two regions with potentially opposite functions (E.T. Jordan, J.R. Cherry, J.M. Walker, R.D. Vierstra [1996] Plant J 9: 243-257). One region is required for activity and correct apoprotein/chromophore interactions, whereas the second appears to regulate phytochrome activity. We have further resolved these functional regions by analysis of N-terminal deletion and alanine-scanning mutants of oat (Avena sativa) phyA in transgenic tobacco (Nicotiana tabacum). The results indicate that the region involved in chromophore/apoprotein interactions contains two separate segments (residues 25-33 and 50-62) also required for biological activity. The region that regulates phyA activity requires only five adjacent serines (Sers) (residues 8-12). Removal or alteration of these Sers generates a photoreceptor that increases the sensitivity of transgenic seedlings to red and FR light more than intact phyA. Taken together, these data identify three distinct regions in the N-terminal domain necessary for photoreceptor activity, and further define the Ser-rich region as an important site for phyA regulation.

Strikingly different localization of galectin-3 and galectin-4 in human colon adenocarcinoma T84 cells. Galectin-4 is localized at sites of cell adhesion

Two beta-galactoside-binding proteins were found to be prominently expressed in the human colon adenocarcinoma T84 cell line. Cloning and sequencing of one, a 36-kDa protein, identified it as the human homolog of galectin-4, a protein containing two carbohydrate binding domains and previously found only in the epithelial cells of the rat and porcine alimentary tract. The other, a 29-kDa protein, is galectin-3, containing a single carbohydrate binding domain, previously found in a number of different cell types including human intestinal epithelium. Despite the marked similarities in the carbohydrate binding domains of these two galectins, their cellular distribution patterns are strikingly different and vary with cellular conditions. In confluent T84 cells, galectin-4 is mostly cytosolic and concentrated at the basal membrane, whereas galectin-3 tends to be concentrated in large granular inclusions mostly at the apical membrane. In subconfluent T84 cells, each galectin is distributed to specific domains of lamellipodia, with galectin-4 concentrated in the leading edge and galectin-3 more proximally. Such different localization of galectins-4 and -3 within T84 cells implies different targeting mechanisms, ligands, and functions. The localization of galectin-4 suggests a role in cell adhesion which is also supported by the ability of immobilized recombinant galectin-4 to stimulate adhesion of T84 cells.

Phenytoin as an alternative treatment for preeclampsia

Magnesium sulfate is the preferred treatment for preeclampsia in the United States. Its use has been criticized because of the maternal, fetal, and neonatal side effects and its tocolytic action during labor. Phenytoin has been identified as an alternative for the treatment of preeclampsia and the prevention of eclampsia. The effects of magnesium sulfate with those of phenytoin on the mother, the fetus, and the neonate are compared. A nursing protocol summarizes nursing care for the obstetric patient receiving phenytoin. Phenytoin has certain demonstrable clinical advantages when used in the intrapartum period with patients with preeclampsia.

The amino-terminus of phytochrome A contains two distinct functional domains

The N-terminus of phytochrome A is important for the structural integrity and biological activity of the photoreceptor. Mutational analysis of the N-terminus by two different strategies created two distinct photoreceptors, one inactive and the other hyperactive when expressed in transgenic tobacco, suggesting that this region has multiple functional domains. To identify critical residues within this N-terminal region, a series of smaller deletions of oat phytochrome A were created, designated NB (delta49-62), NC (delta6-47), ND (delta7-21), NE (delta2-5), and NF (delta6-12), and compared with a previously characterized deletion mutant NA (delta7-69) and full-length oat phytochrome A. Using photochemical properties as a measure of chromoprotein structure, it was found that the region between residues 13 and 62 was important for the spectral integrity of the photoreceptor. These deletion mutants were also biologically inactive when expressed in both mature tobacco plants and seedlings grown under continuous far-red or red light. In contrast, deletion of the serine-rich region between residues 6 and 12 did not alter the photochemical properties but did produce a hyperactive photoreceptor, indicating this region may be involved in down-regulating phytochrome A activity. The data show that the N-terminus of phytochrome A contains two functional domains, one necessary for conformational stability and biological activity (residues 13-62), and the other involved in attenuating phytochrome responses (residues 6-12).

Expression of functional oat phytochrome A in transgenic rice

To investigate the biological functions of phytochromes in monocots, we generated, by electric discharge particle bombardment, transgenic rice (Oryza sativa cv Gulfmont) that constitutively expresses the oat phytochrome A apoprotein. The introduced 124-kD polypeptide bound chromophore and assembled into a red- and far-red-light-photoreversible chromoprotein with absorbance spectra indistinguishable from those of phytochrome purified from etiolated oats. Transgenic lines expressed up to 3 and 4 times more spectrophotometrically detectable phytochrome than wild-type plants in etiolated and green seedlings, respectively. Upon photo-conversion to the far-red-absorbing form of phytochrome, oat phytochrome A was degraded in etiolated seedlings with kinetics similar to those of endogenous rice phytochromes (half-life approximately 20 min). Although plants overexpressing phytochrome A were phenotypically indistinguishable from wild-type plants when grown under high-fluence white light, they were more sensitive as etiolated seedlings to light pulses that established very low phytochrome equilibria. This indicates that the introduced oat phytochrome A was biologically active. Thus, rice ectopically expressing PHY genes may offer a useful model to help understand the physiological functions of the various phytochrome isoforms in monocotyledonous plants.

Site-directed mutagenesis studies on the lima bean lectin. Altered carbohydrate-binding specificities result from single amino acid substitutions

The wild-type seed lima bean lectin (LBL), and recombinant LBL expressed in Escherichia coli show specificity for the human blood group A immunodominant trisaccharide GalNAc alpha 1-3[Fuc alpha 1-2]Gal beta 1-R. We have generated four site-specific mutants of LBL, two of which show altered specificity for extended carbohydrate structures. Four mutants, [C127Y]LBL, [H128P]LBL, [H128R]LBL and [W132F]LBL were expressed in E. coli. Two mutants show altered specificity for the substituent at the C2 hydroxy group of the penultimate Gal in the wild-type ligand which is alpha-L-fucose in the A trisaccharide. The mutant [C127Y]LBL showed specificity for the A disaccharide (GalNAc alpha 1-3Gal) and GalNAc alpha 1-4Gal, with free hydroxyl groups at the C2 position of Gal. The mutant [H128P]LBL bound the Forssman disaccharide structure GalNAc alpha 1-3GalNAc, in which the C2 hydroxyl group is substituted with an acetamido group. The third and fourth mutants, [H128R]LBL and [W132F]LBL, exhibited wild-type specificities, both recognizing the A trisaccharide. All of these mutant lectins bound the terminal GalNAc residues exposed on asialoovine submaxillary mucin, thus indicating that the monosaccharide-binding site had not been altered. We also determined that all but one mutant ([C127Y]LBL) retained the high-affinity binding site for N6 derivatives of adenine, indicative of tetramer formation; each mutant also expressed the low-affinity binding site for 8-anilinonaphthalene 1-sulfonate (1/monomer). Thus, by targeting two residues in LBL, we have identified a region of the protein that is part of the extended carbohydrate-binding site and which is specifically involved in the binding/recognition of substituents at the C2 position of the penultimate Gal of the A disaccharide. We have determined, by site-directed mutagenesis, that an essential Cys residue is involved in the specificity of LBL for the A trisaccharide.

Phytochrome A overexpression in transgenic tobacco. Correlation of dwarf phenotype with high concentrations of phytochrome in vascular tissue and attenuated gibberellin levels

Phytochromes are a family of related chromoproteins that regulate photomorphogenesis in plants. Ectopic overexpression of the phytochrome A in several plant species has pleiotropic effects, including substantial dwarfing, increased pigmentation, and delayed leaf senescence. We show here that the dwarf response is related to a reduction in active gibberellins (GAs) in tobacco (Nicotiana tabacum) overexpressing oat phytochrome A under the control of the cauliflower mosaic virus (CaMV) 35S promoter and can be suppressed by foliar applications of gibberellic acid. In transgenic seedlings, high concentrations of oat phytochrome A were detected in stem and petiole vascular tissue (consistent with the activity of the CaMV 35S promoter), implicating vascular tissue as a potential site of phytochrome A action. To examine the efficacy of this cellular site, oat phytochrome A was also expressed using Arabidopsis chlorophyll a/b-binding protein (CAB) and the Arabidopsis ubiquitin (UBQ1) promoters. Neither promoter was as effective as CaMV 35S in expressing phytochrome in vascular tissue or in inducing the dwarf phenotype. Collectively, these data indicate that the spatial distribution of ectopic phytochrome is important in eliciting the dwarf response and suggest that the phenotype is invoked by elevated levels of the far-red-absorbing form of phytochrome within vascular tissue repressing GA biosynthesis.

Patients' versus nurses' assessments of pain and sedation after cesarean section

OBJECTIVE

To compare nurses' and patients' assessments of pain and sedation in patients receiving epidural or intravenous patient-controlled analgesia (PCA) after cesarean section.

DESIGN

Prospective, randomized study.

SETTING

The perinatal unit and labor and delivery unit in a 1,036-bed university hospital in the mid-Atlantic region.

PARTICIPANTS

Twenty-six patients receiving epidural PCA or intravenous PCA. Nurses participating in the study were assigned as caregivers to the 26 patients.

MAIN OUTCOME MEASURES

Pain and sedation were assessed using 10-cm visual analogue scales completed by both the patient and the patient's nurse twice daily on the day of surgery and on the 1st and 2nd postoperative days.

RESULTS

No significant correlation was found between the nurses' and patients' pain or sedation scores. Chi-square analysis showed that the nurse was as likely to underestimate as to overestimate the patient's pain score. The nurse underestimated the patient's sedation score 85% of the time.

CONCLUSIONS

The results suggest that nurses' and patients' assessments of pain and sedation differ. The routine use of a standardized self-assessment tool, such as the visual analogue scale, is recommended to ensure that analgesic treatment is based on the subjective nature of the patient's pain experience rather than the nurse's judgment.

Signaling among neighboring plants and the development of size inequalities in plant populations

Transgenic tobacco plants that express an oat phytochrome gene (phyA) under control of the cauliflower mosaic virus (CaMV) 35S promoter and display altered photophysiology were used to test the role of light as a vehicle of information in dominance relationships between neighboring plants. Compared with the isogenic wild type, phyA-overexpressing plants showed dramatically reduced morphological responsivity to changes in the red/far red ratio of the incident light and to the proximity of neighboring plants in spacing experiments. In transgenic canopies an increase in stand density caused the small plants of the population to be rapidly suppressed by their neighbors. In wild-type canopies, plants responded to increased density with large morphological changes, and there appeared to be an inverse relationship between the magnitude of this morphological response and the ranking of the individual plant in the population size hierarchy. In these wild-type populations, size inequality increased only moderately with density within the time frame of the experiments. Our results suggest that, in crowded stands, the ability of individual plants to acquire information about their light environment via phytochrome plays a central role in driving architectural changes that, at the population level, delay the development of size differences between neighbors.

The sequence of a second member of the lima bean lectin gene family and the expression and characterization of recombinant lectin in Escherichia coli

The lima bean lectin recognizes terminal alpha-D-GalNAc groups and agglutinates human type A erythrocytes. We have cloned a portion of the gene encoding the alpha subunit of the lima bean lectin. The clone was obtained using the polymerase chain reaction and verified from a genomic clone encoding the mature protein of 253 amino acids. The deduced amino acid sequence has significant overall homology with other leguminous plant lectins and contains all of the known peptide sequences isolated from lima bean lectin (LBL). Southern blot analysis reveals the presence of several genes which hybridize to the cloned gene and which we propose are genes included in the lima bean lectin gene family. We report here the sequence, expression, and characterization of LBL 2, the second member of this gene family. Milligram quantities of soluble active recombinant lima bean lectin (rLBL) were obtained from Escherichia coli, using the T7 RNA polymerase expression system. SDS-polyacrylamide gel electrophoresis and Western blot analysis indicate expression of one protein band of about 27 kDa in induced E. coli cells. This protein cross-reacts with polyclonal antibodies raised against seed lectin (sLBL) and gave a reaction of identity with seed lectin by Ouchterlony double diffusion, specifically agglutinates type A blood cells, and is specifically inhibited by D-GalNAc. The isoelectric point of rLBL is 5.86, whereas those of the seed lectin subunits were determined to be 5.86, 5.58, and 5.20 (previously designated alpha, beta, alpha', respectively). rLBL binds to hydrophobic ligands independent of sugar binding, an observation similar to results obtained with sLBL. However, despite the similar activities described, several significant differences between recombinant and native lima bean lectin were found, including mobility on gel filtration, aggregation in solution, and its CD spectrum. These differences may be due to a number of factors, which will be discussed.

Structural rearrangements of the chloroplast genome provide an important phylogenetic link in ferns

The chloroplast genome of most land plants is highly conserved. In contrast, physical and gene mapping studies have revealed a highly rearranged chloroplast genome in species representing four families of ferns. In all four, there has been a rare duplication of the psbA gene and the order of the psbA, 16S, and 23S rRNA genes has been inverted. Our analysis shows that the described rearrangement results from a minimum of two inversions within the inverted repeat. This chloroplast DNA structure provides unambiguous evidence that phylogenetically links families of ferns once thought to belong to different major evolutionary lineages.

Doppler recordings of fetal movement: II. Comparison with maternal perception

Twenty-seven women were studied to assess the relationship between maternally perceived fetal movement and that recorded by a Doppler device. Eighty-eight percent (433 of 492) of maternally perceived movements were detected by Doppler, but only 16% of movements detected by Doppler were maternally perceived (433 of 2196). When complex movements were classified by duration, those movements lasting between 20-60 seconds were most likely (correlation greater than 0.9) to be perceived by the mother. This Doppler method has the potential to replace maternal event marking and other techniques in the recording of fetal movement.