Site-selective dephosphorylation of the platelet-derived growth factor beta-receptor by the receptor-like protein-tyrosine phosphatase DEP-1

Ligand stimulation of PDGF beta-receptors leads to autophosphorylation of the regulatory tyrosine 857 and of tyrosine residues that in their phosphorylated form serve as docking sites for Src homology 2 domain-containing proteins. Regulation of the PDGF beta-receptor by protein-tyrosine phosphatases is poorly understood. We have investigated PDGF beta-receptor dephosphorylation by receptor-like protein-tyrosine phosphatase DEP-1 using a cell line with inducible DEP-1 expression and by characterizing in vitro dephosphorylation of the PDGF beta-receptor and of receptor-derived phosphopeptides by DEP-1. After DEP-1 induction PDGF beta-receptor.DEP-1 complexes and reduced receptor tyrosine phosphorylation were observed. Phosphopeptide analysis of the PDGF beta-receptors from DEP-1-expressing cells and of the receptors dephosphorylated in vitro by DEP-1 demonstrated that dephosphorylation of autophosphorylation sites of the receptor differed and revealed that the regulatory Tyr(P)(857) was not a preferred site for DEP-1 dephosphorylation. When dephosphorylation of synthetic receptor-derived peptides was analyzed, the selectivity was reproduced, indicating that amino acid sequence surrounding the phosphorylation sites is the major determinant of selectivity. This notion is supported by the observation that the poorly dephosphorylated Tyr(P)(562) and Tyr(P)(857), in contrast to other analyzed phosphorylation sites, are surrounded by basic amino acid residues at positions -4 and +3 relative to the tyrosine residue. Our study demonstrates that DEP-1 dephosphorylation of the PDGF beta-receptor is site-selective and may lead to modulation, rather than general attenuation, of signaling.

2H-Thieno[3,2-e]- and [2,3-e]-1,2-thiazine-6-sulfonamide 1,1-dioxides as ocular hypotensive agents: synthesis, carbonic anhydrase inhibition and evaluation in the rabbit

Novel non-chiral 2H-thieno[3,2-e]- and [2,3-e]-1,2-thiazine-6-sulfonamide 1,1-dioxides were synthesized for evaluation as potential candidates for the treatment of glaucoma. All of the compounds prepared were potent high affinity inhibitors of human carbonic anhydrase II, Ki < 0.5 nM. Additionally, inhibition of recombinant human carbonic anhydrase IV was determined for selected compounds; these were shown to be moderate to potent inhibitors of this isozyme with IC50 values ranging from 4.25 to 73.6 nM. Of the compounds evaluated for their ability to lower intraocular pressure in naturally hypertensive Dutch-belted rabbits, 5a, 17a3, 17b1, 17b2, 17h2 and 17i1 showed significant efficacy (> 20% decrease) in this model following topical ocular administration.

Identification of a testis-specific gene (C15orf2) in the Prader-Willi syndrome region on chromosome 15

Prader-Willi syndrome (PWS) results from the loss of paternal contributions for a 2-Mb imprinted region on the proximal long arm of human chromosome 15. Hitherto, five paternally active genes have been identified in this region (ZNF127, NDN, MAGEL2, SNURF-SNRPN, and IPW). Here we report the identification of a novel gene in the PWS critical region, which has been designated "chromosome 15 open reading frame 2" (C15orf2). C15orf2 is an intronless gene located between MAGEL2 and SNURF-SNRPN. It is associated with a CpG island, which is methylated in all tissues tested except for germ cells. C15orf2 is transcribed as a 7.5-kb mRNA and contains an open reading frame encoding a predicted 1156-amino-acid protein of unknown function. Transcription of C15orf2 occurs exclusively in the testis, and in adult testis samples, we observed biallelic expression. By zoo-blot analysis, we found related sequences in DNA from other primates, but not in nonprimate DNA. We conclude that C15orf2 may play a role in primate spermatogenesis.

The New York State universal newborn hearing screening demonstration project: outpatient outcome measures

OBJECTIVE

To investigate outpatient outcome measures of a multi-center, state-wide, universal newborn hearing screening project.

DESIGN

Eight hospitals participated in a 3-yr, funded project. Each hospital designed its own protocol using common criteria for judging whether an infant passed a hearing screening. Infants were tested in the hospital, and those either failing the in-hospital screening or who were not tested in the hospital (missed) were asked to return 4 to 6 wk after hospital discharge for outpatient rescreening. Those infants failing the outpatient rescreening were referred for diagnostic auditory brain stem response testing. Each hospital used its own audiological equipment and criteria to determine whether a particular infant had a hearing loss. All data were collected and analyzed for individual hospitals, as well as totaled across all hospitals. Data were analyzed in terms of year of program operation, nursery type, and geographic region.

RESULTS

Seventy-two percent of infants who failed the in-hospital screening returned for outpatient testing. The percentage of in-hospital fails returning for retesting was significantly higher than the percentage of in-hospital misses returning for retesting. The percentage of infants returning for retesting increased with successive years of program operation. Some differences were noted in the percentage of infants returning for retesting among hospitals and geographic regions of the state. Some differences in outpatient outcome measures also were noted between infants originally born into the neonatal intensive care unit (NICU) and the well-baby nursery (WBN). The percentage of infants from the NICU who returned for retesting was slightly higher than that for infants from the WBN. The percentage of infants from the WBN passing the outpatient rescreening was higher than that for the NICU infants. The overall prevalence of hearing loss was 1.96/1000, with that in the NICU being 8/1000 and that in the WBN being 0.9/1000. Positive predictive value for permanent hearing loss based on inpatient screening was approximately 4% and based on outpatient rescreening was approximately 22%.

CONCLUSIONS

Several outpatient outcome measures changed with successive years of program operation, suggesting that programs improve over time. Also, some outpatient outcome measures differ between NICU and WBN populations. The differences noted across regions of the state in the percentage of infants returning for outpatient retesting require further research to determine whether differences are due to demographic and/or procedural differences.

New York State universal newborn hearing screening demonstration project: effects of screening protocol on inpatient outcome measures

OBJECTIVE

To examine differences among various test protocols on the fail rate at hospital discharge for infants in the well-baby nursery (WBN) and neonatal intensive care unit (NICU) who received hearing screening through a universal newborn hearing screening demonstration project.

DESIGN

The outcomes of several screening protocols were examined. Two technologies were used: transient evoked otoacoustic emissions (TEOAEs) alone or in combination with the auditory brain stem response (ABR). The performance of test protocols in both nurseries within eight hospitals was examined over a 2- to 3-yr period. In the WBN, six hospitals used a screening protocol of TEOAE technology first followed by an ABR (automated or conventional) technology screening for newborns who referred on TEOAE screening. Two hospitals used TEOAE only in the WBN. Seven hospitals used screening protocols in the NICU that used a combination of TEOAE and ABR technologies (TEOAE technology administered first or second, before or after TEOAE, or TEOAE and ABR tests on all infants). Only one hospital used TEOAE technology exclusively for hearing screening.

RESULTS

Significant differences among screening protocols were found across hospitals in the first, second, and third years of the program. The combination of TEOAE technology and ABR technology (a two-technology screening protocol) resulted in a significantly lower fail rate at hospital discharge than the use of a single-technology (TEOAE). Fail rates at discharge were twice as high using the one-technology protocol versus two-technology protocol, even when the best outcomes from program year 3 were considered exclusively. Results of two-technology versus one-technology protocols were similar in the NICU. Use of a second technology for screening TEOAE fails significantly reduced every hospital that used the protocol's fail rate at discharge.

CONCLUSIONS

A two-technology screening protocol resulted in significantly lower fail rates at hospital discharge in both the WBN and NICU nurseries than use of a single-technology (TEOAE) hearing screening protocol.

The New York State universal newborn hearing screening demonstration project: ages of hearing loss identification, hearing aid fitting, and enrollment in early intervention

OBJECTIVE

To determine the ages of hearing loss identification, hearing aid fitting, and enrollment in early intervention through a multi-center, state-wide universal newborn hearing screening project.

DESIGN

Universal newborn hearing screening was conducted at eight hospitals across New York State. All infants who did not bilaterally pass hearing screening before discharge were recalled for outpatient retesting. Inpatient screening and outpatient rescreening were done with transient evoked otoacoustic emissions and/or auditory brain stem response testing. Diagnostic testing was performed with age appropriate tests, auditory brain stem response and/or visual reinforcement audiometry. Infants diagnosed with permanent hearing loss were considered for hearing aids and early intervention. Ages of hearing loss identification, hearing aid fitting, and enrollment in early intervention were investigated regarding nursery type, risk status, unilateral versus bilateral hearing loss, loss type, loss severity, and state regions.

RESULTS

The prevalence of infants diagnosed with permanent hearing loss was 2.0/1000 (85 of 43,311). Of the 85 infants with hearing loss, 61% were from neonatal intensive care units (NICUs) and 67% were at risk for hearing loss. Of the 36 infants fitted with hearing aids, 58% were from NICUs and 78% were at risk for hearing loss. The median age at identification and enrollment in early intervention was 3 mo. Median age at hearing aid fitting was 7.5 mo. Median ages at identification were less for infants from the well-baby nurseries (WBNs) than for the NICU infants and for infants with severe/profound than for infants with mild/moderate hearing loss, but were similar for not-at-risk and at-risk infants. Median ages at hearing aid fitting were less for well babies than for NICU infants, for not-at-risk infants than for at-risk infants, and for infants with severe/ profound hearing loss than for infants with mild/ moderate hearing loss. However, median ages at early intervention enrollment were similar for nursery types, risk status, and severity of hearing loss.

CONCLUSIONS

Early ages of hearing loss identification, hearing aid fitting, and enrollment in early intervention can be achieved for infants from NICUs and WBNs and for infants at risk and not at risk for hearing loss in a large multi-center universal newborn hearing screening program.

New York State universal newborn hearing screening demonstration project: inpatient outcome measures

OBJECTIVE

To evaluate the feasibility of universal newborn hearing screening by examining inpatient outcome measures from 8 hospitals located in geographically diverse areas of New York State over a 3-yr period.

DESIGN

Funding was provided by the New York State Department of Health to implement predischarge hearing screening programs in the neonatal intensive care units (NICUs) and well-baby nurseries (WBNs) of eight hospitals. Various screening protocols including transient evoked otoacoustic emissions alone or in combination with conventional auditory brain stem response or screening auditory brain stem response were implemented by each site. Measured outcomes included rate of misses, refusals, and fails. Results were analyzed as a function of year of operation, nursery type, and geographic location.

RESULTS

Six out of eight hospitals successfully implemented universal hearing screening during the first year, and the remaining 2 hospitals implemented programs during the second year of the project. Over a period of 3 yr, 69,761 newborns were screened at the eight hospitals representing 96.9% of all live births. The overall fail rate (4.04%) combined with the miss rate (2.61%) resulted in 6.63% of infants referred for outpatient follow-up. Mean data indicated that inpatient outcome measures improved with year of operation, with most individual hospitals also showing improvements. Both fail and miss rates were higher in the NICU than in the WBN and for hospitals located in New York City than in other regions of the state.

CONCLUSIONS

Inpatient outcome measures of a universal newborn hearing screening project, which involved multiple centers across geographically diverse regions of New York State, were acceptable in terms of successfully screening a high percentage of live births and attaining low refer rates for outpatient screening. This study adds to the growing body of literature supporting the feasibility of screening all newborns before hospital discharge.

Protein phosphatase 1beta is required for the maintenance of muscle attachments

Type 1 serine/threonine protein phosphatases (PP1) are important regulators of many cellular and developmental processes, including glycogen metabolism, muscle contraction, and the cell cycle [1] [2] [3] [4] [5]. Drosophila and humans both have multiple genes encoding PP1 isoforms [3] [6] [7]; each has one beta and several alpha isoform genes (alpha(1), alpha(2), alpha(3) in flies, alpha and gamma in humans; mammalian PP1beta is also known as PP1delta). The alpha/beta subtype differences are highly conserved between flies and mammals [6]. Though all these proteins are >85% identical to each other and have indistinguishable activities in vitro, we show here that the Drosophila beta isoform has a distinct biological role. We show that PP1beta9C corresponds to flapwing (flw), previously identified mutants of which are viable but flightless because of defects in indirect flight muscles (IFMs) [8]. We have isolated a new, semi-lethal flw allele that shows a range of defects, especially in muscles, which break away from their attachment sites and degenerate.

Electrospray ionization in the study of the polycondensation of Ti(O-i-C3H7)4 and Ti(O-n-C4H9)4

The polycondensation of Ti(O-i-C3H7)4 (1) and Ti(O-n-C4H9)4 (2), precursors widely employed in sol-gel processes, has been investigated by electrospray ionization mass spectrometry. By analysis of 10(-6) M methanol solutions of compounds 1 and 2, the same ionic species are detected, proving that the first step in the polycondensation reaction is the i-propyl (or n-butyl) alcohol-methanol complete exchange. This reaction leads to the Ti(OCH3)4 (3) species, representing the synthon of the polycondensation. Various oligomers of 3 have been detected and characterized by MS/MS experiments, and the related mechanisms have been discussed. A minor oligomeric series due to hydroxyl-containing polycondensation products has also been characterized.

A 28-kb deletion spanning D15S63 (PW71) in five families: a rare neutral variant?

Methylation analysis with probe PW71 (D15S63) is an established procedure to test patients suspected of having Prader-Willi syndrome or Angelman syndrome. Using this test, we have identified a 28-kb deletion spanning D15S63 in five independent families. Sequence analysis revealed identical breakpoints in all the families. The haplotype data are compatible with a common ancestral origin of the deletion in at least two families. The deletion was not found in 1, 000 unrelated controls. Although the deletion maps within the imprinting-center region, neither maternal nor paternal inheritance of the deletion appears to affect imprinting in proximal 15q. We conclude that the deletion is a rare neutral variant that can lead to false-positive results in the PW71-methylation test.

The EIF3S3 gene encoding the p40 subunit of the translation initiation factor eIF3 has eight exons and maps to the Langer-Giedion syndrome chromosome region on 8q24, but is not the TRPS1 gene

We have mapped the gene encoding the p40 subunit of the eukaryotic translation initiation factor eIF3 (EIF3S3) close to the distal border of the minimal critical region for tricho-rhino-phalangeal syndrome type I (TRPS I) on human chromosome 8q24. Because this location makes EIF3S3 a candidate for the TRPS1 gene, we have determined the genomic structure of the EIF3S3 gene and searched for gene deletions and mutations in patients with TRPS I. The gene has eight exons and is transcribed from telomere to centromere. No deletion could be detected in 32 unrelated patients with an apparently normal karyotype. Sequence analysis of all exons in 15 unrelated patients did not reveal any point mutation either. Our data exclude EIF3S3 as the TRPS1 gene.

Regulation of cell surface tissue transglutaminase: effects on matrix storage of latent transforming growth factor-beta binding protein-1

Using a cytochemical approach, we examined the role of tissue transglutaminase (tTgase, Type II) in the incorporation of latent TGF-beta binding protein-1 (LTBP-1) in the extracellular matrix of Swiss 3T3 fibroblasts in which tTgase expression can be modulated through a tetracycline-controlled promoter. Increased tTgase expression led to an increased rate of LTBP-1 deposition in the matrix, which was accompanied by an increased pool of deoxycholate-insoluble fibronectin. Matrix deposition of LTBP-1 could also be reduced by the competitive amine substrate putrescine. Immunolocalization at the fluorescence and electron microscopic level showed that extracellular tTgase is located at the basal and apical surfaces of cells and at cell-cell contacts, and that LTBP-1 is co-distributed with cell surface tTgase, suggesting an early contribution of tTgase to the binding of LTBP-1 to matrix proteins. LTPB-1 was also found to co-localize with both intracellular and extracellular fibronectin, and increased immunoreactivity for LTBP-1 and fibronectin was found in large molecular weight polymers in the deoxycholate-insoluble matrix of fibroblasts overexpressing tTgase. We conclude that regulation of tTgase expression is important for controlling matrix storage of latent TGF-beta1 complexes and that fibronectin may be one extracellular component to which LTBP-1 is crosslinked when LTBP-1 and tTgase interact at the cell surface. (J Histochem Cytochem 47:1417-1432, 1999)

Inactivation of protein-tyrosine phosphatases as mechanism of UV-induced signal transduction

UV irradiation of cells causes ligand-independent activation of receptor tyrosine kinases. On the basis of dephosphorylation kinetics, UV-induced inactivation of receptor-directed tyrosine phosphatases (PTP) has been proposed as the mechanism of receptor activation (Knebel, A., Rahmsdorf, H. J., Ullrich, A., and Herrlich, P. (1996) EMBO J. 15, 5314-5325). Here we show that four defined protein-tyrosine phosphatases (PTPs), SHP-1, RPTPalpha, RPTPsigma, and DEP-1, are partially inactivated upon UV irradiation of PTP-overexpressing cells. The dephosphorylation of coexpressed platelet-derived growth factor beta (PDGFbeta) receptor by RPTPalpha is inhibited upon UV irradiation. UV converts RPTPalpha into a substrate-trapping enzyme which can coprecipitate PDGFbeta receptor, similarly to the PTP mutant at the active-center cysteine: C433S. In agreement with the proposed mechanism that inactivation of PTPs accounts for receptor tyrosine kinase activation, no evidence for a UV-induced receptor cross-linking could be obtained in PDGFbeta receptor-enriched membrane micelle preparations and in PDGFbeta receptor overexpressing 293 cells. The intrinsic activity of PDGFbeta receptor kinase was required for the UV-induced enhancement of receptor phosphorylation, but was not changed upon UV irradiation. The data support a mechanism of UV-induced signal transduction involving inactivation of PTPs through an unknown reactive intermediate that oxidizes the conserved cysteine in the active sites of PTPs.

Evaluation of a long-chain polyunsaturated fatty acid supplemented formula on growth, tolerance, and plasma lipids in preterm infants up to 48 weeks postconceptional age

BACKGROUND

The last trimester of pregnancy is a period of rapid accretion of long-chain polyunsaturated fatty acids, both in the central nervous system and the body as a whole. Human milk contains these fatty acids, whereas some preterm infant formulas do not. Infants fed formulas without these fatty acids have lower plasma and erythrocyte concentrations than infants fed human milk. Preclinical and clinical studies have demonstrated that single-cell sources (algal and fungal) of long-chain polyunsaturated fatty acids are bioavailable. A balanced addition of fatty acids from these oils to preterm formula results in blood fatty acid concentrations in low birth weight infants comparable to those of infants fed human milk.

METHODS

In the present study the growth, acceptance (overall incidence of discontinuation, reasons for discontinuation, overall incidence and type of individual adverse events), and plasma fatty acid concentrations were compared in three groups of infants fed a long-chain polyunsaturated fatty acid-supplemented preterm infant formula, an unsupplemented control formula, or human milk. The study was prospective, double-blind (formula groups only), and randomized (formula groups only). Two hundred eighty-eight infants were enrolled (supplemented formula group, n = 77; control formula group, n = 78; human milk group, n = 133).

RESULTS

Anthropometric measurements at enrollment, at first day of full oral feeding, and at both 40 and 48 weeks postconceptional age did not differ between the formula groups, whereas the human milk-fed group initially grew at a lower rate. The incidence of severe adverse events was rare and not significantly different between formula groups. The groups fed either human milk or supplemented formula had long-chain polyunsaturated fatty acid concentrations higher than those in the control formula group.

CONCLUSIONS

The results of this study demonstrate the safety and efficacy of a preterm formula supplemented with long-chain polyunsaturated fatty acids from single-cell oils.

Bradykinin B(2) receptor-mediated mitogen-activated protein kinase activation in COS-7 cells requires dual signaling via both protein kinase C pathway and epidermal growth factor receptor transactivation

The signaling routes linking G-protein-coupled receptors to mitogen-activated protein kinase (MAPK) may involve tyrosine kinases, phosphoinositide 3-kinase gamma (PI3Kgamma), and protein kinase C (PKC). To characterize the mitogenic pathway of bradykinin (BK), COS-7 cells were transiently cotransfected with the human bradykinin B(2) receptor and hemagglutinin-tagged MAPK. We demonstrate that BK-induced activation of MAPK is mediated via the alpha subunits of a G(q/11) protein. Both activation of Raf-1 and activation of MAPK in response to BK were blocked by inhibitors of PKC as well as of the epidermal growth factor (EGF) receptor. Furthermore, in PKC-depleted COS-7 cells, the effect of BK on MAPK was clearly reduced. Inhibition of PI3-Kgamma or Src kinase failed to diminish MAPK activation by BK. BK-induced translocation and overexpression of PKC isoforms as well as coexpression of inactive or constitutively active mutants of different PKC isozymes provided evidence for a role of the diacylglycerol-sensitive PKCs alpha and epsilon in BK signaling toward MAPK. In addition to PKC activation, BK also induced tyrosine phosphorylation of EGF receptor (transactivation) in COS-7 cells. Inhibition of PKC did not alter BK-induced transactivation, and blockade of EGF receptor did not affect BK-stimulated phosphatidylinositol turnover or BK-induced PKC translocation, suggesting that PKC acts neither upstream nor downstream of the EGF receptor. Comparison of the kinetics of PKC activation and EGF receptor transactivation in response to BK also suggests simultaneous rather than consecutive signaling. We conclude that in COS-7 cells, BK activates MAPK via a permanent dual signaling pathway involving the independent activation of the PKC isoforms alpha and epsilon and transactivation of the EGF receptor. The two branches of this pathway may converge at the level of the Ras-Raf complex.

The transmembrane protein tyrosine phosphatase RPTPsigma modulates signaling of the epidermal growth factor receptor in A431 cells

Attenuation of epidermal growth factor receptor signaling by the ganglioside G(M3) has previously been found to involve activation of an unknown protein-tyrosine phosphatase (PTP). In transient expression experiments we tested different PTPs for activation towards EGF receptor by G(M3). The transmembrane PTP RPTPsigma but not RPTPalpha or the SH2-domain PTP SHP-1 exhibited elevated activity towards EGF receptor in G(M3)-treated cells. The possible relevance of RPTPsigma for regulation of EGF receptor signaling activity was further explored in stable A431 cells lines inducibly expressing RPTPsigma or RPTPsigma antisense RNA. RPTPsigma expression clearly reduced EGF receptor phosphorylation. Also, soft agar colony formation of respective cell lines was reduced upon RPTPsigma expression whereas RPTPsigma antisense RNA expression augmented both, EGF receptor phosphorylation and soft agar colony formation. In addition, RPTPsigma antisense RNA expression rendered A431 cells resistant to inhibition of EGF receptor phosphorylation by G(M3). We propose that RPTPsigma participates in EGF receptor dephosphorylation in A431 cells, becomes activated by G(M3) via an unknown mechanism and is thereby capable to mediate attenuation of EGF receptor phosphorylation by G(M3).

[Pediatric research in an office-setting network--a new dimension in pediatric research in Israel]

Pediatric care in the community is gradually replacing traditional care in hospitals. Despite that, research activity in the community setting is minimal due to objective difficulties. These are mainly constraints of time, office work and lack of research-supporting logistics. In the past decade, throughout the world, primary physicians interested in research have grouped together and formed research networks. The aim of such networks is to support and promote research in the community. An Israel Pediatric Research in Office-Setting network (IPROS) was established 2 years ago by the Israel Ambulatory Pediatric Association (IAPA). Today, there are over 140 pediatricians listed in IPROS, representing the heterogeneous composition of pediatricians in Israel. The network's policy is defined by a joint steering committee. The committee is composed of IAPA representatives, senior network members and Schneider Hospital senior investigators. The research subjects are diverse, and represent common practical issues. Effective intra-net communication is vital to the existence of the network, and is accomplished by 3 modalities: 1) semiannual updates by mail, 2) e-mail, using an electronic mailing list to facilitate connection between members, 3) semi-annual meetings. Research budgets are derived from public sources like the Ministry of Health and IAPA, and private sources such as pharmaceutical companies. The administration of the network is supported by Schneider Children's Medical Center, and financed by IAPA.

The effect of intravenously administered magnesium on platelet function in patients after cardiac surgery

After cardiac surgery, magnesium is often administered for prophylaxis and treatment of cardiac arrhythmias. Magnesium, however, inhibits platelet function in vitro and in healthy volunteers. We performed a randomized, blinded, and placebo-controlled study to investigate the effect of magnesium on platelet function in patients after cardiac surgery. We studied patients who underwent uneventful coronary revascularization with cardiopulmonary bypass on the first postoperative day. Before and after an infusion of either 5.4 mmol magnesium (n = 19) or saline (n = 20), platelet function was investigated by means of in vitro bleeding time, platelet aggregation, and flow-cytometric assays. In addition, to investigate platelet function in vitro, 1, 5, and 10 mM magnesium were added to platelet-rich plasma before and 24 h after surgery in 30 patients. Compared with the control group, magnesium prolonged the in vitro bleeding time (22%) and inhibited ADP- and collagen-induced platelet aggregation (13% and 17%), platelet P-selectin expression (18%), and the binding of fibrinogen to the platelet glycoprotein IIb/IIIa receptor (10%). Magnesium also led to significant dose-dependent inhibition of platelet aggregation (19%), P-selectin expression (14%), and fibrinogen binding (11%) before and after surgery in vitro. Although the antithrombotic effect of magnesium may be beneficial in patients after coronary revascularization, large-dose magnesium therapy should be carefully considered in patients with impaired platelet function and co-existing bleeding disorders.

IMPLICATIONS

In a randomized, blinded, placebo-controlled study of patients 24 h after coronary artery bypass grafting, IV administered magnesium inhibited platelet function in vitro and in vivo.

An essential role for NF-kappaB in human CD34(+) bone marrow cell survival

The transcription factor, NF-kappaB, is important for T-cell activation, B-cell maturation, and human immunodeficiency virus transcription and plays a role in alternatively mediating and protecting against apoptosis in a variety of cell types. However, a role for NF-kappaB in human CD34(+) bone marrow cells has not been described. We provide evidence here that virtually all human CD34(+) bone marrow cells express NF-kappaB that can be activated by exposure to phorbol 12-myristate 13-acetate and a variety of cytokines, eg, tumor necrosis factor alpha, interleukin-3, and granulocyte-macrophage colony-stimulating factor. In addition, we demonstrate that NF-kappaB may be required for human CD34(+) bone marrow cell clonogenic function and survival. These results offer insight into a new role for NF-kappaB in maintaining survival and function in hematopoietic stem and progenitor cells and suggest that proposed strategies involving inhibition of NF-kappaB activation as an adjunct to cancer chemotherapy should be approached with caution.

Radiation-induced signal transduction. Mechanisms and consequences

Over a dose range up to 50 Gy of low-LET (linear energy transfer) ionizing radiation and up to 5 kJ/m2 UVB, mammalian cells convert molecular damage into productive response (mostly gain of function). By inactivation of negative regulatory components, such as protein tyrosine phosphatases as one mechanism discovered, the balance between restraining and stimulating influences is disturbed and an increase in signal flow results. Also DNA damage causing transcriptional arrest produces a signalling cascade of as yet unknown details. Such stimulation of the intracellular communication network can lead to apoptosis, elevated cell cycling and differentiation processes possibly including repair and recombination. The outcome likely depends on integration of all signals received which is as yet ill-understood. Although accurate determinations of low-dose inductions have not been achieved for technical reasons, the dose-response curves of induced signal transduction likely show threshold characteristics, in contrast to the direct consequences of DNA damage.

Structural analysis of inhibitor binding to human carbonic anhydrase II

X-ray crystal structures of carbonic anhydrase II (CAII) complexed with sulfonamide inhibitors illuminate the structural determinants of high affinity binding in the nanomolar regime. The primary binding interaction is the coordination of a primary sulfonamide group to the active site zinc ion. Secondary interactions fine-tune tight binding in regions of the active site cavity >5 A away from zinc, and this work highlights three such features: (1) advantageous conformational restraints of a bicyclic thienothiazene-6-sulfonamide-1,1-dioxide inhibitor skeleton in comparison with a monocyclic 2,5-thiophenedisulfonamide skeleton; (2) optimal substituents attached to a secondary sulfonamide group targeted to interact with hydrophobic patches defined by Phe131, Leu198, and Pro202; and (3) optimal stereochemistry and configuration at the C-4 position of bicyclic thienothiazene-6-sulfonamides; the C-4 substituent can interact with His64, the catalytic proton shuttle. Structure-activity relationships rationalize affinity trends observed during the development of brinzolamide (Azopt), the newest carbonic anhydrase inhibitor approved for the treatment of glaucoma.

Medical, cognitive, emotional, and behavioral outcomes in school-age children conceived by in-vitro fertilization

Assessed long-term effects of assisted reproduction technologies of in-vitro fertilization (IVF) and related techniques of embryo transfer (ET) on children's adjustment. 51 school-age Israeli children conceived by IVF/ET were compared with 51 control-matched children conceived spontaneously. The assessment included a comprehensive medical evaluation, a psychological examination, teachers' reports, parents' reports, and children's self-reports. As compared with controls, IVF/ET children did not reveal significant differences in physical and neurological status or on cognitive measures of IQ, visual-motor coordination, visual memory, and verbal comprehension. Nevertheless, the IVF/ET children were scored lower by teachers on measures of socioemotional adjustment in school and on self-report measures of anxiety, aggression, and depression. Among IVF/ET children, the tendency to be at a greater risk for emotional disturbances was exacerbated among boys and among children whose parents were older.

The detection and measurement of depersonalization disorder

Depersonalization disorder comprises one of the four major dissociative disorders and yet remains poorly studied. There are no reports describing the application of dissociation scales to this population. Our goal was to investigate the applicability of four such scales to depersonalization disorder and to establish screening criteria for the disorder. Two general dissociation scales and two depersonalization scales were administered to 50 subjects with DSM-III-R depersonalization disorder and 20 healthy control subjects. The depersonalization disorder group scored significantly higher than the normal control group in all scales and subscales. Factor analysis of the Dissociative Experiences Scale (DES) yielded three factors as proposed previously, absorption, amnesia, and depersonalization/derealization. A DES cutoff score of 12, markedly lower than those previously proposed for the screening of other dissociative disorders, is required for the sensitive detection of depersonalization disorder. Alternatively, the DES pathological dissociation taxon (DES-taxon) score recently generated in the literature appears more sensitive to the detection of depersonalization disorder and is better recommended for screening purposes. The other three scales were fairly strongly correlated to the DES, suggesting that they may measure similar but not identical concepts, and cutoff scores are proposed for these scales also. General implications for the screening and quantification of depersonalization pathology are discussed.