bluuebunny/crossref_metadata_2025 huggingface dataset:
Technology for Enhanced Transfusion Safety
Authors: Dzik Walter H.
Published: November 2005

Data from reporting systems around the world document that non-infectious hazards are the leading cause of serious morbidity or mortality resulting from blood transfusion. Among these non-infectious hazards, mis-transfusion represents the most frequently observed serious hazard and occurs at an estimated rate of 1 in 14,000 transfusions. Mis-transfusion events result from “lapse errors” (slip ups) rather than cognitive mistakes. Lapse errors are more likely to occur during repetitive tasks when individuals are distracted, rushed, or fatigued—conditions to which machines are not susceptible. The final bedside check and the collection of patient samples for pre-transfusion testing are key “error spots” and are candidates for new technology innovation. Existing technology includes non-computerized devices; bedside devices based on bar code technology; and the use of radiofrequency chips. Several commercial systems employing bar-code technology have reached clinical application or are undergoing refinement. Radiofrequency-based systems are on the near horizon. Nearly all systems begin with the application of machine-readable data to the patient’s wristband. The third error spot—the decision to transfuse—will be a challenging area for future application of information technology. Computerized physician order-entry, decision support and ultimately active computer-based decision-making are expected to enhance transfusion decisions. Despite the explosive growth in information technology in modern society, healthcare has lagged behind many other sectors in the use of enhanced information technology. Studies are needed to identify which technologies improve patient outcomes. Healthcare workers, administrators, and regulators need to embrace the use of new technology in order to reduce errors and improve safety for patients.
Cancer Survivorship—Pediatric Issues
Authors: Bhatia Smita
Published: November 2005

The last three decades have seen tremendous improvements in survival of children diagnosed with cancer, with the 5-year survival rate approaching 80%. This improvement in survival has resulted in a growing population of childhood cancer survivors. Use of cancer therapy at an early age can produce complications that may not become apparent until years later. Approximately two thirds of the survivors of childhood cancer will experience at least one late effect, and about one third will experience a late effect that is severe or life threatening. Long-term complications in childhood cancer survivors, such as impairment in growth and development, neurocognitive dysfunction, cardiopulmonary compromise, endocrine dysfunction, renal impairment, gastrointestinal dysfunction, musculoskeletal sequelae, and subsequent malignancies, are related not only to the specific therapy employed, but may also be determined by individual host characteristics. We review the known late effects of treatment in survivors of childhood cancer in order to suggest reasonable starting points for evaluation of specific long-term problems in this unique but growing population. The Children’s Oncology Group (COG) has developed risk-based, exposure-related guidelines for follow-up care that are available at www.surivorshipguidelines.org.
Anemia in the Elderly: A Public Health Crisis in Hematology
Authors: Guralnik Jack M. , Ershler William B. , Schrier Stanley L. , Picozzi Vincent J.
Published: November 2005

Over 3 million people in the United Staes aged 65 years and older are anemic. This condition is associated with significant functional impairment and, perhaps, increased mortality. In March 2004, the American Society of Hematology (in conjunction with the National Institute of Aging) convened a “blue ribbon” panel of twenty physicians who are experts on various aspects of this topic. This paper highlights important consensus concepts resulting from that meeting. In particular, four areas of thought are shared. First, the epidemiology of anemia in the elderly is reviewed, including its definition, its expression in different racial groups, and its wide-ranging manifestations. Second, the pathophysiology of anemia in the elderly is reviewed as pertains to three general etiological categories (nutritional, chronic diseases, and so-called “unexplained” anemias). Particular emphasis is given to pathophysiologic mechanisms of anemia that are potentially unique to this age group. Third, a practical approach to the diagnosis and management of anemia for this patient population for the practicing hematologist is provided. Finally, the public health implications of anemia in the elderly for key stakeholder constituencies will be discussed in the oral presentation.
Stem Cell Therapy for Sickle Cell Disease: Transplantation and Gene Therapy
Authors: Walters Mark C.
Published: November 2005

HLA-identical sibling hematopoietic cell transplantation (HCT) for sickle cell disease (SCD) has a strong track record of efficacy and there is growing appreciation that its benefits exceed its risks in selected individuals. In contrast, the clinical utility of replacement gene therapy for sickle cell disease remains unproven. Its challenge is to ensure viral transduction into hematopoietic stem cells (HSCs) and to generate safe, stable, erythroid-specific replacement gene expression at a level that is sufficient to have a clinical effect. The clinical necessity for fulfilling all these criteria may make this genetic disorder among the most complex to treat successfully by gene therapy. But the experience of HCT for SCD has proven that eliminating the βS-globin gene is curative when the transfer is stable. Thus replacement gene therapy for sickle cell disease remains a subject of intense interest and investigation.
Chronic Granulomatous Disease and Other Disorders of Phagocyte Function
Authors: Dinauer Mary C.
Published: November 2005

The analysis of specific gene defects in disorders of phagocyte function has shed light on important aspects of the innate immune response. Each disorder has distinctive features in the clinical presentation and characteristic microbial pathogens. Chronic granulomatous disease has been extensively studied both in patient series and in mouse models. New insights continue to be obtained regarding the role of the nicotinamide dinucleotide phosphate (NADPH) oxidase and related enzymes in host defense and other aspects of the inflammatory response, as well as optimal management of this disorder. Approaches based on hematopoietic stem cell transplantation and gene therapy offer promise for the future, but are still under investigation. Also briefly summarized are updates on newly described leukocyte adhesion defects and on inherited susceptibility to mycobacterial infection due to defects in interleukin (IL)-12 and interferon-γ pathways.
Endothelial protein C receptor (CD201) explicitly identifies hematopoietic stem cells in murine bone marrow
Authors: Balazs Alejandro B. , Fabian Attila J. , Esmon Charles T. , Mulligan Richard C.
Published: November 2005

The hematopoietic stem cell (HSC) is a unique cell type found in bone marrow, which has the capacity for both self-renewal and differentiation into all blood lineages. The identification of genes expressed specifically in HSCs may help identify gene products vital to the control of self-renewal and/or differentiation, as well as antigens capable of forming the basis for improved methods of stem cell isolation. In previous studies, we identified a number of genes that appeared to be differentially expressed in murine bone marrow–derived HSCs, using microarray technology. We report here that one of those genes, encoding the murine endothelial protein C receptor (EPCR), is expressed at high levels within the bone marrow in HSCs. Bone marrow cells isolated on the basis of EPCR expression alone are highly enriched for hematopoietic reconstitution activity, showing levels of engraftment in vivo comparable to that of stem cells purified using the most effective conventional methods. Moreover, evaluation of cell populations first enriched for stem cell activity by conventional methods and subsequently fractionated on the basis of EPCR expression indicates that stem cell activity is always associated with EPCR-expressing cells. Based on our findings, we believe EPCR represents the first known marker that `explicitly' identifies hematopoietic stem cells within murine bone marrow.
Genetic variation in bactericidal/permeability-increasing protein influences the risk of developing rapid airflow decline after hematopoietic cell transplantation
Authors: Chien Jason W. , Zhao Lue Ping , Hansen John A. , Fan Wen Hong , Parimon Tanyalak , Clark Joan G.
Published: November 2005

Innate immunity is involved in the biology of graft versus host disease and common airway diseases. We screened 15 genes in this pathway using a linkage disequilibrium-based approach to identify potential candidate genes that may be involved in the development of airflow obstruction after hematopoietic cell transplantation. Sixty-nine single-nucleotide polymorphisms were selected for assessment in a discovery cohort (n = 363). Significant associations were validated in a validation cohort (n = 209). Expression of the candidate gene was demonstrated by detecting gene transcript and protein in malignant and normal small airway epithelial cells. In the discovery cohort, 133 patients developed significant airflow decline. Four patient and donor bactericidal/permeability-increasing (BPI) haplotypes were associated with a 2-fold to 3-fold increased risk of developing significant airflow decline (P values, .004-.038). This association was confirmed in the validation cohort, which had 66 patients with significant airflow decline, with 9 significant haplotypes (P values, .013-.043). BPI gene transcript and protein were detected in airway epithelial cells. These results suggest mutations in the BPI gene significantly influence the risk of developing rapid airflow decline after hematopoietic cell transplantation and may represent a novel therapeutic target for this form of airway disease.
Keratinocyte growth factor (KGF) is required for postnatal thymic regeneration
Authors: Alpdogan Önder , Hubbard Vanessa M. , Smith Odette M. , Patel Neel , Lu Sydney , Goldberg Gabrielle L. , Gray Daniel H. , Feinman Jared , Kochman Adam A. , Eng Jeffrey M. , Suh David , Muriglan Stephanie J. , Boyd Richard L. , van den Brink Marcel R. M.
Published: November 2005

Keratinocyte growth factor (KGF) is a member of the fibroblast growth factor family that mediates epithelial cell proliferation and differentiation in a variety of tissues, including the thymus. We studied the role of KGF in T-cell development with KGF-/- mice and demonstrated that thymic cellularity and the distribution of thymocyte subsets among KGF-/-, wildtype (WT), and KGF+/- mice were similar. However, KGF-/- mice are more vulnerable to sublethal irradiation (450 cGy), and a significant decrease was found in thymic cellularity after irradiation. Defective thymopoiesis and peripheral T-cell reconstitution were found in KGF-/- recipients of syngeneic or allogeneic bone marrow transplant, but using KGF-/- mice as a donor did not affect T-cell development after transplantation. Despite causing an early developmental block in the thymus, administration of KGF to young and old mice enhanced thymopoiesis. Exogenous KGF also accelerated thymic recovery after irradiation, cyclophosphamide, and dexamethasone treatment. Finally, we found that administering KGF before bone marrow transplantation (BMT) resulted in enhanced thymopoiesis and peripheral T-cell numbers in middle-aged recipients of an allogeneic BM transplant. We conclude that KGF plays a critical role in postnatal thymic regeneration and may be useful in treating immune deficiency conditions. (Blood. 2006;107:2453-2460)
αIIbβ3 biogenesis is controlled by engagement of αIIb in the calnexin cycle via the N15-linked glycan
Authors: Mitchell W. Beau , Li JiHong , French Deborah L. , Coller Barry S.
Published: November 2005

Although much is known about αIIbβ3 structure and function, relatively little is understood about its biogenesis. Thus, we studied the kinetics of pro-αIIb production and degradation, focusing on whether proteasomal degradation or the calnexin cycle participates in these processes. In pulse-chase analyses, the time to half-disappearance of pro-αIIb (t1/2) was the same in (1) HEK293 cells transfected with (a) αIIb plus β3, (b) αIIb alone, (c) mutant V298FαIIb plus β3, or (d) I374TαIIb plus β3; and (2) murine wild-type and β3-null megakaryocytes. Inhibition of the proteasome prolonged the t1/2 values in both HEK293 cells and murine megakaryocytes. Calnexin coprecipitated with αIIb from HEK293 cells transfected with αIIb alone, αIIb plus β3, and V298FαIIb plus β3. For proteins in the calnexin cycle, removal of the terminal mannose residue of the middle branch of the core N-linked glycan results in degradation. Inhibition of the enzyme that removes this mannose residue prevented pro-αIIb degradation in β3-null murine megakaryocytes. αIIb contains a conserved glycosylation consensus sequence at N15, and an N15Q mutation prevented pro-αIIb maturation, complex formation, and degradation. Our findings suggest that pro-αIIb engages the calnexin cycle via the N15 glycan and that failure of pro-αIIb to complex normally with β3 results in proteasomal degradation.
Macrophages from C3-deficient mice have impaired potency to stimulate alloreactive T cells
Authors: Zhou Wuding , Patel Hetal , Li Ke , Peng Qi , Villiers Marie-Bernadette , Sacks Steven H.
Published: November 2005

Impaired T-cell reactivity is a feature of C3-deficient mice in several disease models. The mechanism behind the reduced T-cell response is, however, poorly understood. We explored the hypothesis that antigen-presenting cells (APCs) from C3-/- mice have impaired potency to stimulate antigen-specific T cells, in an alloantigen-dependent model. Our results show that C3-/- macrophages have reduced ability to elicit alloreactive T-cell responses in vitro and in vivo, affecting both the primary and secondary responses. The C3 status of donor macrophages had a major impact on the CD4 T-cell response. The impaired CD4 T-cell response was associated with reduced expression of MHC class II on the surface of C3-/- macrophages, without loss of class II gene expression. Furthermore, inhibition of C3 gene expression in C3+/+ macrophages reduced their ability to stimulate alloreactive T cells, suggesting that endogenous production of C3 could in part contribute to the potency of APCs. Our data provide compelling evidence that C3 deficiency modulates the potency of APCs to stimulate the T-cell response, suggesting a critical role for complement in the maintenance of APC function. This could offer a partial explanation as to why the T-cell response is impaired in C3-/- mice. (Blood. 2006;107:2461-2469)
FLT3-ITD–, but not BCR/ABL-transformed cells require concurrent Akt/mTor blockage to undergo apoptosis after histone deacetylase inhibitor treatment
Authors: Cai Dali , Wang Ying , Ottmann Oliver G. , Barth Peter J. , Neubauer Andreas , Burchert Andreas
Published: November 2005

Leukemias are differentially sensitive to histone deacytelase inhibitor (HDI)–induced apoptosis, but molecular reasons for this remain unclear. We here show that BCR/ABL-, but not FMS-like tyrosine kinase 3 (FLT3)–internal tandem duplication (ITD)–transformed 32D cells or primary acute myeloid leukemia (AML) blasts undergo apoptosis after treatment with the HDI valproic acid (VPA) plus all-trans retinoic acid (VPA/ATRA). A particular VPA/ATRA responsiveness of Philadelphia chromosome–positive (Ph+) acute lymphatic leukemia (ALL) was confirmed in a therapy-refractory patient in vivo. HDI-stimulated apoptosis in Ph+ cells was caspase dependent, but independent from Akt pathway inhibition. Conversely, separate blockage of the Akt/mTor-signaling pathway was a prerequisite for overcoming apoptosis resistance to VPA/ATRA in FLT3-ITD cells, and primary AML blasts (n = 9). In conclusion, constitutive Akt activation causes apoptosis resistance to VPA/ATRA in AML, but not in Ph+ leukemia. This warrants the application of HDI-based therapies in poor-risk Ph+ ALL, and the use of Akt/mTor inhibitors to overcome HDI resistance in AML.
Hypoxic induction of an HIF-1α–dependent bFGF autocrine loop drives angiogenesis in human endothelial cells
Authors: Calvani Maura , Rapisarda Annamaria , Uranchimeg Badarch , Shoemaker Robert H. , Melillo Giovanni
Published: November 2005

Hypoxia is a major pathophysiological condition for the induction of angiogenesis, which is a crucial aspect of growth in solid tumors. In mammalian cells, the transcriptional response to oxygen deprivation is largely mediated by hypoxia-inducible factor 1 (HIF-1), a heterodimer composed of HIF-1α and HIF-1β subunits. However, the response of endothelial cells to hypoxia and the specific involvement of HIF-α subunits in this process are still poorly understood. We show that human umbilical vein endothelial cells (HUVECs) cultured in the absence of growth factors survive and form tubelike structures when cultured under hypoxic, but not normoxic, conditions. HUVECs expressed both HIF-1α and HIF-2α when cultured under hypoxic conditions. Transfection of HIF-1α, but not HIF-2α, siRNA to HUVECs completely abrogated hypoxic induction of cords. Neutralizing antibodies to bFGF, but not IGF-1, VEGF, or PDGF-BB, blocked survival and sprouting of HUVECs under hypoxic conditions, suggesting the existence of an autocrine loop induced by low oxygen levels. Notably, bFGF-dependent induction of cord formation under normoxic conditions required HIF-1α activity, which was also essential for hypoxic induction of bFGF mRNA and protein expression. These results uncover the existence of an HIF-1α–bFGF amplification pathway that mediates survival and sprouting of endothelial cells under hypoxic conditions.
Therapeutic lung lavages in children and adults
Authors: Paschen Christian , Reiter Karl , Stanzel Franz , Teschler Helmut , Griese Matthias
Published: November 2005

Background

Pulmonary alveolar proteinosis (PAP) is a rare disease, characterized by excessive intra-alveolar accumulation of surfactant lipids and proteins. Therapeutic whole lung lavages are currently the principle therapeutic option in adults. Not much is known on the kinetics of the wash out process, especially in children.

Methods

In 4 pediatric and 6 adult PAP patients 45 therapeutic half lung lavages were investigated retrospectively. Total protein, protein concentration and, in one child with a surfactant protein C mutation, aberrant pro-SP-C protein, were determined during wash out.

Results

The removal of protein from the lungs followed an exponential decline and averaged for adult patients 2 – 20 g and <0.5 to 6 g for pediatric patients. The average protein concentration of consecutive portions was the same in all patient groups, however was elevated in pediatric patients when expressed per body weight. The amount of an aberrant pro-SP-C protein, which was present in one patient with a SP-C mutation, constantly decreased with ongoing lavage. Measuring the optical density of the lavage fluid obtained allowed to monitor the wash out process during the lavages at the bedside and to determine the termination of the lavage procedure at normal protein concentration.

Conclusion

Following therapeutic half lung lavages by biochemical variables may help to estimate the degree of alveolar filling with proteinaceous material and to improve the efficiency of the wash out, especially in children.
PtdIns(3)P accumulation in triple lipid-phosphatase-deletion mutants triggers lethal hyperactivation of the Rho1p/Pkc1p cell-integrity MAP kinase pathway
Authors: Parrish William R. , Stefan Christopher J. , Emr Scott D.
Published: November 2005

In the budding yeast Saccharomyces cerevisiae, the regulation of phosphatidylinositol 3-phosphate [PtdIns(3)P] is an essential function shared by the myotubularin-related phosphatase Ymr1p and the synaptojanin-like phosphatases Sjl2p and Sjl3p. The aim of this study was to gain further insight into the mechanisms underlying the toxicity of PtdIns(3)P accumulation in ymr1Δ sjl2Δ sjl3Δ mutant cells. We conducted a genetic screen to isolate genes that, when overexpressed, would rescue the conditional lethality of ymr1Δ sjl2Δ sjl3Δ triple-mutant cells expressing YMR1 from the dextrose-repressible GAL1 promoter. This approach identified 17 genes that promoted growth of the triple mutant on media containing dextrose. Interestingly, the most frequently isolated gene product was a truncated form of PKC1 (Pkc1-T615) that lacked the C-terminal kinase domain. This Pkc1-T615 fragment also rescued the lethality of ymr1ts sjl2Δ sjl3Δ cells at restrictive temperature, and further mapping of the rescuing activity showed that the N-terminal Rho1-GTP-interacting HR1 domains (Pkc1-T242) were sufficient. This indicated that the PKC1 fragments might act by interfering with Rho1-GTP signal propagation. Consistent with this, deletion of the ROM2 gene, which encodes a major Rho1p guanine-nucleotide exchange factor, bypassed the lethal effect of PtdIns(3)P accumulation in ymr1Δ sjl2Δ sjl3Δ triple-mutant cells. Furthermore, cells deficient in phosphoinositide 3-phosphatase (PI 3-phosphatase) activity were defective for Rho1p/Pkc1p pathway regulation, which included an inability of these cells to adapt to heat stress. Taken together, the results of this study indicated that aberrant Rho1p/Pkc1p signaling contributes to the lethal effects of PtdIns(3)P accumulation in cells deficient in PI 3-phosphatase activity.
SV2A and SV2C are not vesicular Ca2+ transporters but control glucose-evoked granule recruitment
Authors: Iezzi Mariella , Theander Sten , Janz Roger , Loze Chantal , Wollheim Claes B.
Published: November 2005

Synaptic vesicle protein 2 (SV2) is expressed in neuroendocrine cells as three homologous isoforms, SV2A, SV2B and SV2C. Ca2+-dependent function in exocytosis has been attributed to SV2A and SV2B, without elucidation of the mechanism. The role of SV2C has not yet been addressed. Here we characterize the three SV2 isoforms and define their involvement in regulated insulin secretion. SV2A and SV2C are associated with insulin-containing granules and synaptic-like-microvesicles (SLM) in INS-1E insulinoma and primary β-cells, whereas SV2B is only present on SLM. Neither overexpression nor isoform-specific silencing of SV2A or SV2C by RNA interference modifies depolarization-triggered cytosolic [Ca2+] rises or secretory granule [Ca2+], measured with a VAMP-2 aequorin chimera. This strongly argues against any Ca2+ transport function of SV2. Moreover, up- or downregulation of these isoforms has no influence on K+-induced insulin release suggesting that SV2 does not affect the Ca2+-dependent step(s) of exocytosis. By contrast, glucose-elicited secretion is inhibited during the sustained rather than the early phase, placing the action of SV2 on the recruitment of granules from the reserve pool to the plasma membrane. This conclusion is reinforced by capacitance measurements in glucose-stimulated SV2C-deficient cells. Like capacitance, evoked and basal hormone release are attenuated more by silencing of SV2C compared with SV2A. This indicates only partial redundancy and highlights a key role for SV2C in the secretory process.
Carboxyamidotriazole-induced inhibition of mitochondrial calcium import blocks capacitative calcium entry and cell proliferation in HEK-293 cells
Authors: Mignen Olivier , Brink Christine , Enfissi Antoine , Nadkarni Aditi , Shuttleworth Trevor J. , Giovannucci David R. , Capiod Thierry
Published: November 2005

Blocking calcium entry may prevent normal and pathological cell proliferation. There is evidence suggesting that molecules such as carboxyamidotriazole, widely used in anti-cancer therapy based on its ability to block calcium entry in nonexcitable cells, also have antiproliferative properties. We found that carboxyamidotriazole and the capacitative calcium entry blocker 2-aminoethoxydiphenyl borate inhibited proliferation in HEK-293 cells with IC50 values of 1.6 and 50 μM, respectively. Capacitative calcium entry is activated as a result of intracellular calcium store depletion. However, non-capacitative calcium entry pathways exist that are independent of store depletion and are activated by arachidonic acid and diacylglycerol, generated subsequent to G protein coupled receptor stimulation. We found that carboxyamidotriazole completely inhibited the capacitative calcium entry and had no effect on the amplitude of arachidonic-acid-activated non-capacitative calcium entry. However, investigation of the effects of carboxyamidotriazole on mitochondrial calcium dynamics induced by carbachol, capacitative calcium entry and exogenously set calcium loads in intact and digitonin-permeabilized cells revealed that carboxyamidotriazole inhibited both calcium entry and mitochondrial calcium uptake in a time-dependent manner. Mitochondrial inner-membrane potential was altered by carboxyamidotriazole treatment, suggesting that carboxyamidotriazole antagonizes mitochondrial calcium import and thus local calcium clearance, which is crucial for the maintenance of capacitative calcium entry.
Bax activation and translocation to mitochondria mediate EGF-induced programmed cell death
Authors: Tikhomirov Oleg , Carpenter Graham
Published: November 2005

The ErbB family of receptor tyrosine kinases is involved in the regulation of cell proliferation, differentiation and apoptosis. Previous studies indicate that cells expressing elevated levels of the EGFR and ErbB-2 undergo programmed cell death in response to EGF or other EGFR ligands. However, the detailed mechanisms of EGF-induced apoptosis are unclear. This report demonstrates that in the cells undergoing EGF-dependent apoptosis Bax changes its conformation and forms multimeric aggregates, which accumulate on the mitochondrial membrane. Bax activation and translocation to the mitochondria induces a loss of mitochondrial transmembrane potential and cell death. Also, during EGF-induced apoptosis there is downregulation of Bcl-xL, an anti-apoptotic protein. Expression of Bcl-xL in cells susceptible to EGF-dependent apoptosis prevents cell death. The data indicate that addition of EGF does not result in a significant release of cytochrome c from mitochondria and EGF-induced apoptosis is mainly caspase independent.
Neurite outgrowth involves adenomatous polyposis coli protein and β-catenin
Authors: Votin Violet , Nelson W. James , Barth Angela I. M.
Published: November 2005

Neuronal morphogenesis involves the initial formation of neurites and then differentiation of neurites into axons and dendrites. The mechanisms underlying neurite formation are poorly understood. A candidate protein for controlling neurite extension is the adenomatous polyposis coli (APC) protein, which regulates membrane extensions, microtubules and β-catenin-mediated transcription downstream of Wnt signaling. APC is enriched at the tip of several neurites of unpolarized hippocampal neurons and the tip of only the long axon in polarized hippocampal neurons. Significantly, APC localized to the tip of only one neurite, marked by dephospho-tau as the future axon, before that neurite had grown considerably longer than other neurites. To determine whether neurite outgrowth was affected by β-catenin accumulation and signaling, a stabilized β-catenin mutant was expressed in PC12 cells, and neurite formation was measured. Stabilized β-catenin mutants accumulated in APC clusters and inhibited neurite formation and growth. Importantly, these effects were also observed was independently of the gene transcriptional activity of β-catenin. These results indicate that APC is involved in both early neurite outgrowth and increased growth of the future axon, and that β-catenin has a structural role in inhibiting APC function in neurite growth.
A role for the fission yeast Rqh1 helicase in chromosome segregation
Authors: Win Thein Z. , Mankouri Hocine W. , Hickson Ian D. , Wang Shao-Win
Published: November 2005

Schizosaccharomyces pombe Rqh1 protein is a member of the RecQ DNA helicase family. Members of this protein family are mutated in several human genome instability syndromes, including Bloom, Werner and Rothmund-Thomson syndromes. RecQ helicases participate in recombination repair of stalled replication forks or DNA breaks, but the precise mechanisms that lead to the development of cancer in these diseases have remained obscure. Here, we reveal a function for Rqh1 in chromosome segregation even in the absence of exogenous insult to the DNA. We show that cells lacking Rqh1 are delayed in anaphase progression, and show lagging chromosomal DNA, which is particularly apparent in the rDNA locus. This mitotic delay is dependent on the spindle checkpoint, as deletion of mad2 abolishes the delay as well as the accumulation of Cut2 in rqh1Δ cells. Furthermore, relieving replication fork arrest in the rDNA repeat by deletion of reb1+ partially suppresses rqh1Δ phenotypes. These data are consistent with the function of the Top3-RecQ complex in maintenance of the rDNA structure by processing aberrant chromosome structures arising from DNA replication. The chromosome segregation defects seen in the absence of functional RecQ helicases may contribute to the pathogenesis of human RecQ helicase disorders.
Hyper-adhesion in desmosomes: its regulation in wound healing and possible relationship to cadherin crystal structure
Authors: Garrod David R. , Berika Mohamed Y. , Bardsley William F. , Holmes David , Tabernero Lydia
Published: November 2005

The resistance of tissues to physical stress is dependent upon strong cell-cell adhesion in which desmosomes play a crucial role. We propose that desmosomes fulfil this function by adopting a more strongly adhesive state, hyper-adhesion, than other junctions. We show that the hyper-adhesive desmosomes in epidermis resist disruption by ethylene glycol bis(2-aminoethyl ether)-N,N,N′N′-tetraacetic acid (EGTA) and are thus independent of Ca2+. We propose that Ca2+ independence is the normal condition for tissue desmosomes. Ca2+ independence is associated with an organised arrangement of the intercellular adhesive material exemplified by a dense midline. When epidermis is wounded, desmosomes in the wound-edge epithelium lose hyper-adhesiveness and become Ca2+ dependent, i.e. readily dissociated by EGTA. Ca2+-dependent desmosomes lack a midline and show narrowing of the intercellular space. We suggest that this indicates a less-organised, weakly adhesive arrangement of the desmosomal cadherins, resembling classical cadherins in adherens junctions. Transition to Ca2+ dependence on wounding is accompanied by relocalisation of protein kinase C α to desmosomal plaques suggesting that an `inside-out' transmembrane signal is responsible for changing desmosomal adhesiveness. We model hyper-adhesive desmosomes using the crystal packing observed for the ectodomain of C-cadherin and show how the regularity of this 3D array provides a possible explanation for Ca2+ independence.
The axonal transport of mitochondria
Authors: Hollenbeck Peter J. , Saxton William M.
Published: November 2005

Organelle transport is vital for the development and maintenance of axons, in which the distances between sites of organelle biogenesis, function, and recycling or degradation can be vast. Movement of mitochondria in axons can serve as a general model for how all organelles move: mitochondria are easy to identify, they move along both microtubule and actin tracks, they pause and change direction, and their transport is modulated in response to physiological signals. However, they can be distinguished from other axonal organelles by the complexity of their movement and their unique functions in aerobic metabolism, calcium homeostasis and cell death. Mitochondria are thus of special interest in relating defects in axonal transport to neuropathies and degenerative diseases of the nervous system. Studies of mitochondrial transport in axons are beginning to illuminate fundamental aspects of the distribution mechanism. They use motors of one or more kinesin families, along with cytoplasmic dynein, to translocate along microtubules, and bidirectional movement may be coordinated through interaction between dynein and kinesin-1. Translocation along actin filaments is probably driven by myosin V, but the protein(s) that mediate docking with actin filaments remain unknown. Signaling through the PI 3-kinase pathway has been implicated in regulation of mitochondrial movement and docking in the axon, and additional mitochondrial linker and regulatory proteins, such as Milton and Miro, have recently been described.
AGI-1067: A Novel Vascular Protectant for Prevention of Restenosis
Authors: Franks Amy M , Gardner Stephanie F
Published: November 2005

Objective:

To review the synthesis, pharmacology, clinical trials, and adverse effects of AGI-1067, a novel agent for preventing restenosis.

Data Sources:

Literature searches were conducted using MEDLINE (1966–July 2005) and International Pharmaceutical Abstracts (1970–July 2005) for English-language articles containing the search terms AGI-1067, AGI 1067, and probucol. In addition, bibliographies from relevant articles were reviewed for additional references.

Study Selection and Data Extraction:

All articles identified from data sources were reviewed for relevant information. Applicable information was included in this review.

Data Synthesis:

AGI-1067, a derivative of the lipid-lowering agent probucol, is the first of a new class of drugs termed vascular protectants. It has antioxidant and lipid-lowering effects. In addition, it inhibits inflammatory processes without resultant immunosuppression through its selective inhibition of vascular cell adhesion molecule-1 expression. AGI-1067 also exhibited anti-atherosclerotic effects in preclinical studies. Relatively short-term treatment with AGI-1067 showed positive results compared with probucol in preventing restenosis in patients undergoing percutaneous coronary intervention. AGI-1067 appears to be well tolerated and holds important advantages over probucol in that it has fewer adverse effects on high-density lipoprotein cholesterol and the QT interval.

Conclusions:

The favorable safety profile of AGI-1067 offers potential advantages over its precursor, probucol. Preclinical and clinical studies indicate that it possesses antioxidant, antiinflammatory, and lipid-lowering properties. Ongoing Phase II and III studies will determine AGI-1067's place in therapy for the prevention of restenosis and reduction in cardiovascular events in patients undergoing percutaneous intervention for coronary atherosclerosis.
Generic Substitution of Antihypertensive Drugs: Does it Affect Adherence?
Authors: Wijk Boris LG Van , Klungel Olaf H , Heerdink Eibert R , Boer Anthonius de
Published: November 2005

Background:

Generic substitution is an important opportunity to reduce the costs of pharmaceutical care. However, pharmacists and physicians often find that patients and brand-name manufacturers have doubt about the equivalence of the substituted drug. This may be reflected by decreased adherence to therapy.

Objective:

To assess the association between generic substitution and nonadherence to antihypertensive drugs.

Methods:

We conducted a matched cohort study between January 1, 1999, and December 31, 2002. Data were obtained from PHARMO, a record linkage system containing drug-dispensing records from community pharmacies and linked hospital discharge records of approximately 950 000 people in the Netherlands. Residents of 30 medium-sized cities who initiated antihypertensive drug therapy were potential subjects. Refill adherence with antihypertensive drugs after substitution was determined; those with refill adherence below 80% were considered nonadherent.

Results:

Four hundred sixty-three patients with a substitution in therapy and 565 controls, matched on age, gender, therapy start date, duration of use, and generic product code, were identified. Of the patients who switched from brand-name to generic formulations (“substituted”), 13.6% were nonadherent, and of the non-substituted patients (those who did not switch to generic), 18.7% were nonadherent (OR 0.68; 95% aph.1G163CI 0.48 to 0.96). The association was absent in males. None of the patients discontinued the medication. No differences in hospitalizations for cardiovascular disease in the 6 months after the substitution were observed.

Conclusions:

Generic substitution of antihypertensive drugs does not lead to lower adherence or more discontinuation and cardiovascular disease–related hospitalizations compared with brand-name therapy. When a less-expensive antihypertensive generic equivalent becomes available, generic substitution should be considered to achieve economic benefits.
Preparation and Characterization of Fe-PILCs. Influence of the Synthesis Parameters
Authors: Valverde José Luis , Romero Amaya , Romero Rubí , García Prado Belén , Sánchez María Luz , Asencio Isaac
Published: November 2005

Iron-pillared clays (Fe-PILCs) were synthesized from hydrolyzed FeCl3 solutions added to NaOH solutions using different synthesis conditions. X-ray diffraction, N2 adsorption-desorption, chemical analysis, thermogravimetric analysis, differential thermal analysis, temperature-programmed desorption of ammonia and temperature-programmed reduction were used to characterize the resulting Fe-pillared clays (Fe-PILCs). A higher degree of pillaring was obtained when the Fe content was adjusted to 60 mmoles of Fe/g of clay. It was observed that higher values of this ratio led to worse acidity and textural characteristics, a consequence of the probable formation of Fe oxides that could not only deposit on the surface but also block the pores formed during the pillaring process. Likewise, it was found that the amount of Fe that can be introduced depended on the OH/Fe ratios. Total surface and micropore area decreased and Fe content increased with increasing pillaring solution concentrations. Finally, all pillared samples prepared here were thermally stable at temperatures up to 400°C.
Effects of Ethylene Glycol Saturation Protocols on XRD Patterns: A Critical Review and Discussion
Authors: Mosser-Ruck Regine , Devineau Karine , Charpentier Delphine , Cathelineau Michel
Published: November 2005

Study of the transformation of smectite to illite, chlorite or vermiculite via interstratified clay minerals needs precise qualitative and quantitative determinations of the different layers in the mixed-layer clays and is generally based on X-ray diffraction (XRD) patterns after specific treatments of the clay samples. Saturation with K or Mg followed by ethylene glycol (EG) solvation are classical methods used to identify high-charge smectite and vermiculite. These procedures have been applied to two experimental clays, one composed of smectite layers and the second, a mixture of vermiculite and smectite layers. Different methods of glycolation (EG vapor or liquid EG) produce significant differences in the XRD patterns. Comparison with literature data indicates that K-saturated, high-charge smectite (≈0.8 < total charge <1/unit-cell) and Mg-vermiculite (whatever its charge) do not expand in ethylene glycol vapor (d values ≈14–15 Å). Expansion to 17 Å in liquid ethylene glycol occurs for Mg-vermiculite with a total charge of <~1.2/unit-cell and for K-saturated, high-charge smectite, when the tetrahedral charge is <≈0.7/unit-cell. This study shows that: (1) glycolation procedures need to be standardized; (2) the use of saturation protocols using both liquid ethylene glycol and ethylene glycol vapor yields useful additional information about the distribution of charges in clay minerals.
Structural Changes of Allophane During Purification Procedures as Determined by Solid-State 27Al and 29Si NMR
Authors: Hiradate Syuntaro
Published: November 2005

Allophanes are poorly crystalline and quasi-stable aluminosilicate minerals, the structures of which are sensitive to chemical treatment. In the present study, solid-state 27Al and 29Si nuclear magnetic resonance (NMR) spectra of allophane samples were monitored as they went through several purification procedures. It was confirmed that no significant structural changes were caused by boiling with 6% H2O2 to remove organic matter, by size fractionation (sonification), by sedimentation, by precipitation at pH 4.0, or by dithionite-citrate-bicarbonate treatment for the removal of Fe (hydr)oxides. Hot 5% Na2CO3 treatment for the removal of reactive silica-alumina gels and adsorbed citrate from allophane samples, however, decreased signal intensity corresponding to imogolite-like Si (Q33VIAl, −78 ppm in 29Si NMR) and increased signal intensities corresponding to IVAl (55 ppm in 27Al NMR) and possibly X-ray amorphous aluminosilicates (centered at −85 ppm in 29Si NMR). Cold (room temperature) 5% Na2CO3 treatment for 16 h proved to be effective in avoiding these structural changes.
Kaolin Deposits from the Northern Sector of the Cunene Anorthosite Complex (Southern Angola)
Authors: Saviano Giovanna , Violo Maurizio , Pieruccini Umberto , Lopes da Silva Emidio Tertulliano
Published: November 2005

The Mevaiela kaolin deposits are located in the northern part of the anorthositic-gabbro massif within the Cunene complex (southern Angola) and were formed by the alteration of basic anorthosites and gabbros. The Mevaiela area is part of an elevated region which is located between two extensive NNW-SSE fracture systems. Several kaolinite samples were collected from a quarry (main excavation) and from drill-holes as well as from surficial occurrences in the Cunene complex. Chemical analyses, X-ray diffraction, differential thermal analysis, scanning electron microscopy and isotope analyses were performed in order to model the kaolinite occurrences. The alteration of the anorthosite to kaolin approaching the main excavation is characterized by significant decrease in alkaline-earth and transition metals (Ca, Mg, Fe, Co, Ni and Mn) between the average anorthosite and the kaolin. The crystallinity indices suggest that the kaolin contains kaolinite with a reasonably well ordered structure and near the transition between T (triclinic) and pM (pseudo monoclinic).

Mineral exploration tools have been evaluated during this study to assist in future kaolin exploration in the Cunene anorthosite complex.

Isotopic analysis of O and D indicates that Ca-feldspar alteration is essentially due to meteoric fluids, over a different range of temperatures. Furthermore, the presence of quartz-feldspar veinlets in the kaolinite bodies could be the result of hydrothermal activity linked to post-anorthosite granite intrusions of the so-called ‘red granite’. Kaolinite from Cunene plots on or close to the kaolinite line into the ‘warm temperature in tropical region’ area (surficial samples). Samples from drill-holes plot on the left and show the largest displacement from the KS line; these samples also have a relatively reduced δD range of values (−65 to −98%). However, if supergene processes take place in the presence of waters of meteoric origin at temperatures similar to typical surface temperatures, the clays thus formed should plot either in the vicinity of the KS line or be displaced towards lower δO18 and higher δD, depending on both the temperature and relative proportion of clay to water.
Intraneuronal β-Amyloid Expression Downregulates the Akt Survival Pathway and Blunts the Stress Response
Authors: Magrané Jordi , Rosen Kenneth M. , Smith Roy C. , Walsh Kenneth , Gouras Gunnar K. , Querfurth Henry W.
Published: November 2005

Early events in Alzheimer's disease (AD) pathogenesis implicate the accumulation of β-amyloid (Aβ) peptide inside neurons in vulnerable brain regions. However, little is known about the consequences of intraneuronal Aβ on signaling mechanisms. Here, we demonstrate, using an inducible viral vector system to drive intracellular expression of Aβ42 peptide in primary neuronal cultures, that this accumulation results in the inhibition of the Akt survival signaling pathway. Induction of intraneuronal Aβ42 expression leads to a sequential decrease in levels of phospho-Akt, increase in activation of glycogen synthase kinase-3β, and apoptosis. Downregulation of Akt also paralleled intracellular Aβ accumulationin vivoin the Tg2576 AD mouse model. Overexpression of constitutively active Akt reversed the toxic effects of Aβ through a mechanism involving the induction of heat shock proteins (Hsps). We used a small-interfering RNA approach to explore the possibility of a link between Akt activity and Hsp70 expression and concluded that neuroprotection by Akt could be mediated through downstream induction of Hsp70 expression. These results suggest that the early dysfunction associated with intraneuronal Aβ accumulation in AD involve the associated impairments of Akt signaling and suppression of the stress response.
Quinoline and Benzimidazole Derivatives: Candidate Probes forIn VivoImaging of Tau Pathology in Alzheimer's Disease
Authors: Okamura Nobuyuki , Suemoto Takahiro , Furumoto Shozo , Suzuki Masako , Shimadzu Hiroshi , Akatsu Hiroyasu , Yamamoto Takayuki , Fujiwara Hironori , Nemoto Miyako , Maruyama Masahiro , Arai Hiroyuki , Yanai Kazuhiko , Sawada Tohru , Kudo Yukitsuka
Published: November 2005

Neurofibrillary tangles (NFTs), neuropil threads, and neuritic elements of senile plaques predominantly comprise hyperphosphorylated tau protein and represent pathological characteristics of Alzheimer's disease (AD). These lesions occur before the presentation of clinical symptoms and correlate with the severity of dementia.In vivodetection of these lesions would thus prove useful for preclinical diagnosis of AD and for tracking disease progression. The present study introduces three novel compounds, 4-[2-(2-benzoimidazolyl)ethenyl]-N,N-diethylbenzenamine (BF-126), 2-[(4-methylamino)phenyl]quinoline (BF-158), and 2-(4-aminophenyl)quinoline (BF-170), as candidate probes forin vivoimaging of tau pathology in the AD brain. When solutions of these compounds are injected intravenously into normal mice, these agents exhibit excellent brain uptake and rapid clearance from normal brain tissue. These compounds display relatively lower binding affinity to β-amyloid fibrils and higher binding affinity to tau fibrils, compared with previously reported probe BF-168. In neuropathological examination using AD brain sections, BF-126, BF-158, and BF-170 clearly visualize NFTs, neuropil threads, and paired helical filament-type neuritis. Autoradiography using11C-labeled BF-158 further demonstrated labeling of NFTs in AD brain sections. These findings suggest the potential usefulness of quinoline and benzimidazole derivatives forin vivoimaging of tau pathology in AD.