bluuebunny/crossref_metadata_2025 huggingface dataset:
Plant chemical discriminations by an herbivorous iguanid lizard, Sauromalus ater
Authors: Cooper William , Flowers Matthew
Published: July 2002

We experimentally studied the ability of the iguanid lizard Sauromalus ater to discriminate between plant and animal foods and control stimuli using only chemical cues. When chemicals were presented on cotton swabs, the lizards exhibited stronger responses, as indicated by tongue-flicking and biting, to chemical stimuli from romaine lettuce than from crickets and control substances. Responses to plant and animal food did not differ significantly in S. ater, which eats animal prey only occasionally in natural populations. Although there were no significant differences between responses to cricket chemicals and other stimuli for the entire data set, those individuals that ate or attacked crickets tongue-flicked at high rates in response to cricket chemicals. Based on the presence of herbivory and plant chemical discrimination in three iguanid genera, it is likely that plant chemical discrimination is ubiquitous in iguanids. Given the uncertainty of iguanian phylogeny, the evolution of herbivory and response to plant chemicals cannot be traced with confidence. However, it appears very likely that lingually mediated plant chemical discriminations evolved in the common ancestor of Iguanidae or earlier in iguanian history in response to a shift to an herbivorous diet.
FILIAL IMPRINTING AND LEADERSHIP AMONG CHICKS IN FAMILY INTEGRATION OF THE DOMESTIC FOWL
Authors: Collias Nicholas
Published: July 2002

Experiments are reported on filial imprinting and leadership among white leghorn chicks in relation to family integration. Chicks hatched in isolation were given their first exposure to certain parental stimuli (a moving person or clucking sounds recorded from a broody hen) at various ages after hatching from the first to 10th day. Logistic regression and multiple likelihood analysis of the results showed that a significant tendency to follow or to be attracted to parental stimuli was much the greatest during the first day after hatching and then declined exponentially during the rest of the first week. There was a significant correlation between visual and auditory responses to parental stimuli, as well as between a chick's positive responses to clucking and the giving of distress cries by the chick when clucking ceased. Some individual chicks showed a significant tendency to lead the other chicks of a group to stimuli representing the mother, such as a source of warmth, or to the maternal voice (recorded clucking from a speaker).
SWIMMING RESPONSE TO WATER CURRENT IN PARATYA AUSTRALIENSIS KEMP, 1917 (DECAPODA, ATYIDAE) UNDER LABORATORY CONDITIONS
Authors: Bunn Stuart , Hancock Marty
Published: July 2002

The swimming response to flow of the freshwater shrimp Paratya australiensis Kemp, 1917, was examined in a small recirculating laboratory stream. On three occasions during 1993 larvae, juveniles, small and large adults, and ovigerous females were collected from headwater populations and tested in the laboratory at current speeds of 10 and 30 cm s-1. Juvenile and adult shrimps showed the same strong positive rheotactic response at velocities of 10 and 30 cm s-1. However, large adults moved upstream more rapidly than juveniles and small adults. This response was not influenced by the time of year of collection or time of day tested (day/night). Ovigerous females showed a weak response to flow and tended to maintain position rather than move into the current. Early stage larvae (stages III and IV) were not able to maintain position at the lowest velocities. The positive rheotactic response of shrimps, particularly large adults, is seen as an adaptation to compensate for downstream movement of larvae by drift and juvenile and adult displacement during high discharge events. La nage en reponse au courant chez la crevette d'eau douce Paratya australiensis Kemp, 1917, a ete examinee en laboratoire dans un petit courant continu d'eau. A trois reprises durant l'annee 1993, des larves, des juveniles, de petits et grands adultes, ainsi que des femelles ovigeres ont ete collectes dans populations situees en amont et testes au laboratoire a des vitesses de courant de 10 a 30 cm s-1. Les crevettes juveniles et adultes ont repondu par une forte rheotaxie positive aux vitesses de 10 a 30 cm s-1. Cependant, les adultes de grande taille se sont deplaces vers l'amont plus rapidement que les juveniles et les petits adultes. Cette reponse n'a pas ete influencee par le moment du prelevement, que ce soit au cours de l'annee ou de la journee (jour/nuit). Les femelles ovigeres ont donne une faible reponse au courant et tendaient a maintenir leur position plutot qu'a se deplacer dans le courant. Les jeunes larves (stades III et IV) n'etaient pas capables de maintenir leur position aux vitesses les plus basses. La rheotaxie positive des crevettes, en particulier des grands adultes, est consideree comme une adaptation pour compenser le mouvement des larves entrainees vers l'aval par le courant et le deplacement des jeunes et des adultes au moment des hautes eaux.
MORPHOMETRIC ANALYSIS AND REPRODUCTIVE BIOLOGY OF THE CRAB CHARYBDIS AFFINIS (DECAPODA, BRACHYURA, PORTUNIDAE) FROM THE ZHUJIANG ESTUARY, CHINA
Authors: Chu
Published: July 2002

Morphometric characters and organ indices were analyzed in Charybdis affinis collected at different seasons from the Zhujiang estuary, China. The crab is heterochelous, with pronounced right handedness in both sexes. There is a marked sexual difference in relative growth of the cheliped. The female abdomen increases in size at puberty, which is also accompanied by a reduced allometric growth rate. Analysis of gonad development gave the estimate of 50% gonadal maturity at 42 and 36 mm carapace width for females and males, respectively. The hepatosomatic index of female crabs is inversely related to the gonadosomatic index indicating the role of the hepatopancreas in storage of nutrients necessary for ovarian development in the reproductive season. Les caracteres morphologiques et les indices relatifs aux organes ont ete analyses chez Charybdis affinis, recolte a differentes saisons dans l'estuaire du Zhujiang, Chine. Le crabe presente une heterochelie, la pince droite etant tres developpee dans les deux sexes. Il existe une difference sexuelle marquee dans la croissance relative du chelipede. L'abdomen femelle s'accroot en taille a la puberte, ce qui s'accompagne aussi d'un taux de croissance allometrique reduit. L'analyse du developpement des gonades a donne une maturite estimee a 50% pour des femelles et males, respectivement, ayant une largeur de la carapace de 42 et 36 mm. L'indice hepatosomatique des crabes femelles est inversement proportionnel a l'indice gonadosomatique ce qui indique le role de l'hepatopancreas dans le stockage des nutriments necessaire au developpement ovarien lors de la reproduction.
Host status differences and their relevance to damage by Meloidogyne incognita
Authors: Ehwaeti Mahmoud , Fargette Mireille , Phillips Mark , Trudgill David
Published: July 2002

Four populations of Meloidogyne incognita were tested on 57 species of plants from temperate and tropical regions. Juveniles of one or more populations invaded, and induced galls on almost all plants. Except for the population from the West Indies which induced most galls on Nicotiana spp., there was no obvious relationship between the origins of populations and their ability to induce galls on plants from particular regions. Although most plants were hosts for all four populations, many produced only a few galls/egg masses with some of the populations. The differences in galling between populations, and the interaction with plant species were both significant (P < 0.001). Poor hosts often contained fewer juveniles and the rate of juvenile development was often decreased compared with good hosts. Solanum nigrum was an exception in that it was invaded by fewer juveniles than susceptible tomato, but rates of development were similar. The effect of host status differences in four plant species on damage by M. incognita was investigated but only the growth of susceptible tomato was decreased. The growth of the non-host Urtica dioica, of the poor host Datura metal, and of an intermediate host S. nigrum, was unaffected. Unterschiede im Wirtsstatus und ihre Bedeutung fur den durch Meloidogyne incognita verursachten Schaden - Vier Populationen von Meloidogyne incognita wurden an 57 Pflanzenarten aus gemassigten und tropischen Gebieten gepruft. Juvenile einer oder mehrerer Populationen wanderten in fast alle Pflanzen ein und induzierten Gallen. Mit Ausnahme der Population von den Westindischen Inseln, die an Nicotiana spp. die meisten Gallen induzierte, bestand keine deutliche Beziehung zwischen der Herkunft der Populationen und ihrer Fahigkeit, an Pflanzen bestimmter Gebiete Gallbildung zu induzieren. Obwohl die meisten Pflanzen Wirte fur alle vier Populationen waren, bildeten viele von ihnen mit einigen Populationen nur wenige Gallen/Eimassen. Die Unterschiede zwischen den Populationen in Bezug auf Gallbildung und auf Wechselwirkungen mit den Pflanzen waren beide significant (P < 0.001). Schlechte Wirte enthielten oft weniger Juvenile als gute Wirte, und die Entwicklungsrate der Juvenilen war oft vermindert im Vergleich zu guten Wirten. Solanum nigrum bildete insofern eine Ausnahme, als weniger Juvenile eindrangen als in anfallige Tomaten, die Entwicklungsraten aber ahnlich waren. Die Wirkung der Unterschiede im Wirtsstatus auf die Schadigung durch M. incognita wurde an vier Pflanzenarten untersucht. Nur das Wachstum von anfalligen Tomaten wurde vermindert. Das Wachstum des Nichtwirtes Urtica dioica, des schlechten Wirtes Datura metal und des massig guten Wirtes S. nigrum wurde nicht beeinflusst.
Accurate quantitative analysis of clay and other minerals in sandstones by XRD: comparison of a Rietveld and a reference intensity ratio (RIR) method and the importance of sample preparation
Authors: Hillier S.
Published: July 2002

X-ray diffraction is used widely for quantitative analysis of geological samples but studies which document the accuracy of the methods employed are not numerous. Synthetic sandstones of known composition are used to compare a ‘routine application’ of a Rietveld and a reference intensity ratio (RIR) method of quantitative phase analysis. Both methods give similar results accurate to within ~±3 wt.% at the 95% confidence level. The high degree of accuracy obtained is believed to depend to a large extent on the spray-drying method of sample preparation used to eliminate preferred orientation.
Hydromechanical effects: (I) on the Na-smectite microtexture
Authors: Alcover J . -F. , Qi Y. , Al-mukhtar M. , Bonnamy S. , Bergaya F.
Published: July 2002

Changes in particle organization and pore-spaces with applied mechanical and hydraulic stresses were followed using TEM, SAXS mercury porosimetry and gas adsorption for two Na-smectites, Laponite and hectorite, with similar structural formulae but different particle sizes. The TEM images show that hectorite has particles larger and more anisotropic than those of Laponite. The particles order perpendicularly to the direction of axial mechanical stress and become disoriented under hydraulic stress. According to the SAXS results, Laponite is composed of 1 – 3 small layers and hectorite of more compact (10 – 80 layers) particles. In Laponite, mechanical stress strongly reduces the amount of macropores but does not affect micropores and mesopores; hydraulic stress increases the macropores. In hectorite, the pore-volume is lower than in Laponite. The different techniques used yield complementary results and show the considerable effect of layer dimension on the behaviour and microtexture parameters of smectite submitted to hydromechanical stresses.
Effects of chemical composition and temperature of heating on the infrared spectra of Li-saturated dioctahedral smectites. (II) Near-infrared region
Authors: Madejová J. , Bujdák J. , Petit S. , Komadel P.
Published: July 2002

Diffuse reflectance spectra in the near-infrared region are presented for Li-saturated smectites heated up to 200°C. The smectites included three montmorillonites, an Fe-beidellite and a ferruginous smectite. Unheated samples showed a complex band near 7060 cm-1 assigned to the first overtone of the OH-stretching mode of structural hydroxyl groups and bound H2O. The OH combination bands appeared in the 4600-4300 cm-1 region. Spectra of heated montmorillonites showed an upward shift and splitting of the OH-overtone band into two components near 7170 and 7110 cm-1. The presence of a band near 7170 cm-1, assigned to the overtone of the AlMgLiOH-stretching vibration, implied that local trioctahedral domains were created upon Li(I) fixation in the previously vacant octahedral positions of montmorillonites. The OH combination bands were shifted to higher frequencies and a new band appeared near 4472 cm-1 in the spectra of montmorillonites heated to temperatures in excess of 130°C. No features indicating Li(I) in the structure of Fe-beidellite or ferruginous smectite were observed in the NIR spectra.
Synthesis of thallium-leucite (TlAlSi2O6) pseudomorph
after analcime
Authors: Kyono A. , Kimata M. , Shimizu M. , Saito S. , Nishida N. , Hatta T.
Published: July 2002

Thallium leucite, TlAlSi2O6, has
been synthesized at 450°C for 7 days, under ambient conditions, by the
transformation of dehydrated analcime
NaAlSi2O6 in the presence of excess
TlCl. This substitution of Tl for Na leads to confirmation of a thallium-leucite
pseudomorph after analcime. Their optical properties, X-ray powder diffraction
patterns, electron microprobe analysis, infrared spectra, and X-ray photoelectron
spectroscopy have characterized the synthetic Tl-leucites. The IR spectra show
that the mid-IR modes T-O stretching and
T-O-T bending vibrations for
TlAlSi2O6 are more resemblant of
those for analcime than for leucite,
KAlSi2O6. This resemblance implies
that Tl cation enters the W-site rather than the
S-site in the analcime structure: Na
(S) + H2O
(W) ⇋ □ + K (leucite) ⇋ □ + Tl (Tl- leucite), where
□ represents an S-site vacancy. The mechanism of this
substitution is supported by the crystal chemical constraints: inasmuch as the
S-site is smaller than the
W-site, Tl+ cations being
larger than Na+ plainly prefer the latter site to the former.
One inference from the binding energy for Tl+ by XPS is that
Tl+ occupies the extra-framework site in synthetic leucite
pseudomorph, rather than the smaller tetrahedral site. The difference in Al/Si
disordering between analcime and leucite and the nonstoichiometry due to the solid
solution of the □Si3O6 component into
the leucite structure may provide a fundamental insight into understanding why
TlAlSi2O6 deviates from the trend
defined by K-, Rb- and CsAlSi2O6 leucite
series on the a-c parameter diagram, inasmuch as these
three cations in the leucite structure occupy the
W-sites. Finally, synthesis of
TlAlSi2O6 leucite has an implication
for the existence of other polymorphs due to different degrees of Al/Si
disordering, except for high- and low-temperature leucites already known: natural
leucites crystallized directly through igneous processes are different from those
formed by substitution of K for Na in analcimes.
Inhibition of neutrophil elastase prevents cathelicidin activation and impairs clearance of bacteria from wounds
Authors: Cole Alexander M. , Shi Jishu , Ceccarelli Alejandro , Kim Yong-Hwan , Park Albert , Ganz Tomas
Published: July 2002

The host defense roles of neutrophil elastase in a porcine skin wound chamber model were explored. Analysis of wound fluid by acid-urea polyacrylamide gel electrophoresis, Western blot, and bacterial overlay confirmed that the neutrophil-derived protegrins constituted the major stable antimicrobial polypeptide in the wound fluid. The application to the wound of 0.10 and 0.25 mM N-methoxysuccinyl-alanine-alanine-proline-valine (AAPV) chloromethyl ketone, a specific neutrophil elastase inhibitor (NEI), blocked the proteolytic activation of protegrins and diminished the associated antimicrobial activity as detected by radial diffusion assay againstStaphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans or by bacterial gel overlay against S epidermidis and E coli. The application of the related cathepsin G inhibitor (CGI), benzyloxycarbonyl-glycine-leucine-phenylalanine (ZGLF) chloromethyl ketone, had no effect. In wound chambers that received 106 colony-forming unit (CFU)/mL of S epidermidis, the presence of NEI significantly decreased the 24-hour clearance of bacteria from the wound compared to wounds treated with CGI or solvent only. Neither inhibitor, at 0.10 or 0.25 mM concentration, affected leukocyte accumulation or degranulation in the wound chambers. The in vitro microbicidal decrement due to NEI was restored by an amount of the specific protegrin (PG-1), which was equivalent to the measured difference of protegrin between control and inhibited chambers. Administration of 1 μg/mL exogenous PG-1 4 hours after chamber preparation was sufficient to normalize in vivo antimicrobial activity. Although pharmacologic NEIs are promising candidates as anti-inflammatory drugs, they may impair host defense in part by inhibiting the activation of cathelicidins by neutrophil elastase.
Macrophage inflammatory protein-1α is an osteoclastogenic factor in myeloma that is independent of receptor activator of nuclear factor κB ligand
Authors: Han Je-Ho , Choi Sun Jin , Kurihara Noriyoshi , Koide Masanori , Oba Yasuo , Roodman G. David
Published: July 2002

A complementary DNA expression library derived from marrow samples from myeloma patients was recently screened and human macrophage inflammatory protein-1α (hMIP-1α) was identified as an osteoclastogenic factor expressed in these samples. hMIP-1α enhanced osteoclast (OCL) formation in human marrow cultures and by highly purified OCL precursors in a dose-dependent manner (5-200 pg/mL). Furthermore, hMIP-1α enhanced OCL formation induced by human interleukin-6 (IL-6), which is produced by marrow stromal cells when they interact with myeloma cells. hMIP-1α also enhanced OCL formation induced by parathyroid hormone-related protein (PTHrP) and receptor activator of nuclear factor κB ligand (RANKL), factors also implicated in myeloma bone disease. Time-course studies revealed that the hMIP-1α acted during the last 2 weeks of the 3-week culture period. Reverse transcription–polymerase chain reaction analysis showed that the chemokine receptors for hMIP-1α (CCR1 and CCR5) were expressed by human bone marrow and highly purified early OCL precursors. Furthermore, hMIP-1α did not increase expression of RANKL. These data demonstrate that hMIP-1α is an osteoclastogenic factor that appears to act directly on human OCL progenitors and acts at the later stages of OCL differentiation. These data further suggest that in patients with myeloma, MIP-1α produced by myeloma cells, in combination with RANKL and IL-6 that are produced by marrow stromal cells in response to myeloma cells, enhances OCL formation through their combined effects on OCL precursors.
Regulation of monocyte procoagulant activity in acute myocardial infarction: role of tissue factor and tissue factor pathway inhibitor-1
Authors: Ott Ilka , Andrassy Martin , Zieglgänsberger Dominik , Geith Stefanie , Schömig Albert , Neumann Franz-Josef
Published: July 2002

In acute myocardial infarction (AMI), monocyte procoagulant activity is increased and may contribute to the risk for recurrence and other thrombotic events. This study sought to investigate the role tissue factor (TF) and tissue factor pathway inhibitor-1 (TFPI-1) in the regulation of monocyte procoagulant activity in AMI. Serial venous blood samples were obtained from 40 patients with AMI undergoing revascularization by stent placement. Twenty patients with elective stenting for stable angina served as control subjects. TF proteolytic activity was measured with spectrozyme factor Xa (FXa), TF and TFPI-1 surface expression on monocytes by flow cytometry, RNA expression in whole blood by reverse transcription–polymerase chain reaction, and concentrations of plasma prothrombin fragments F1 + 2 by immunoassay. Forty-eight hours after AMI, an increase was found in TF RNA, followed by an increase in TF surface expression by 24% ± 4% and in plasma concentration of F1 + 2 by 103% ± 17% (P < .05). These changes could not be attributed to the intervention because they did not occur in the control group. TFPI-1 RNA and binding to the monocyte surface remained unchanged. FXa generation by monocytes of patients with AMI increased 53.6% ± 9% in the presence of polyclonal antibodies to TFPI-1, indicating that cell-associated TFPI-1 inhibits monocyte TF activity. The increased monocyte procoagulant activity in AMI was caused by an up-regulation of TF that was partially inhibited by surface-bound TFPI-1. Anticoagulant therapy by direct inhibition of TF activity may, thus, be particularly effective in AMI.
Human cathelicidin, hCAP-18, is processed to the antimicrobial peptide LL-37 by extracellular cleavage with proteinase 3
Authors: Sørensen Ole E. , Follin Per , Johnsen Anders H. , Calafat Jero , Tjabringa G. Sandra , Hiemstra Pieter S. , Borregaard Niels
Published: July 2002

Cathelicidins are a family of antimicrobial proteins found in the peroxidase-negative granules of neutrophils. The known biologic functions reside in the C-terminus, which must be cleaved from the holoprotein to become active. Bovine and porcine cathelicidins are cleaved by elastase from the azurophil granules to yield the active antimicrobial peptides. The aim of this study was to identify the physiological setting for cleavage of the only human cathelicidin, hCAP-18, to liberate the antibacterial and cytotoxic peptide LL-37 and to identify the protease responsible for this cleavage. Immunoelectron microscopy demonstrated that both hCAP-18 and azurophil granule proteins were present in the phagolysosome. Immunoblotting revealed no detectable cleavage of hCAP-18 in cells after phagocytosis. In contrast, hCAP-18 was cleaved to generate LL-37 in exocytosed material. Of the 3 known serine proteases from azurophil granules, proteinase 3 was solely responsible for cleavage of hCAP-18 after exocytosis. This is the first detailed study describing the generation of a human antimicrobial peptide from a promicrobicidal protein, and it demonstrates that the generation of active antimicrobial peptides from common proproteins occurs differently in related species.
Effects of mixed hematopoietic chimerism in a mouse model of bone marrow transplantation for sickle cell anemia
Authors: Iannone Robert , Luznik Leo , Engstrom Laura W. , Tennessee Sherrie L. , Askin Frederic B. , Casella James F. , Kickler Thomas S. , Goodman Steven N. , Hawkins Anita L. , Griffin Constance A. , Noffsinger Lori , Fuchs Ephraim J.
Published: July 2002

Sickle cell anemia (SCA) is an inherited disorder of β-globin, resulting in red blood cell rigidity, anemia, painful crises, organ infarctions, and reduced life expectancy. Allogeneic blood or marrow transplantation (BMT) can cure SCA but is associated with an 8% to 10% mortality rate, primarily from complications of marrow-ablative conditioning. Transplantation of allogeneic marrow after less intensive conditioning reduces toxicity but may result in stable mixed hematopoietic chimerism. The few SCA patients who inadvertently developed mixed chimerism after BMT remain symptom free, suggesting that mixed chimerism can reduce disease-related morbidity. However, because the effects of various levels of mixed chimerism on organ pathology have not been characterized, this study examined the histologic effects of an increasing percentage of normal donor hematopoiesis in a mouse model of BMT for SCA. In lethally irradiated normal mice that were reconstituted with varying ratios of T-cell–depleted marrow from normal and transgenic “sickle cell” mice, normal myeloid chimerism in excess of 25% was associated with more than 90% normal hemoglobin (Hb). However, 70% normal myeloid chimerism was required to reverse the anemia. Organ pathology, including liver infarction, was present in mice with sickle Hb (HbS) levels as low as 16.8% (19.6% normal myeloid chimerism). Histologic abnormalities increased in severity up to 80% HbS, but were less severe in mice with more than 80% HbS than in those with 40% to 80% HbS. Therefore, stable mixed chimerism resulting from nonmyeloablative BMT may reduce the morbidity from SCA, but prevention of all disease complications may require minimizing the fraction of circulating sickle red cells.
The snake venom toxin alboaggregin-A activates glycoprotein VI
Authors: Asazuma Naoki , Marshall Stuart J. , Berlanga Oscar , Snell Daniel , Poole Alastair W. , Berndt Michael C. , Andrews Robert K. , Watson Steve P.
Published: July 2002

The glycoprotein (GP)–Ib-IX-V receptor complex has recently been reported to signal through a pathway similar to that used by the collagen receptor GPVI, with a critical role described for the Fc receptor γ-chain. The evidence for this was based in part on studies with the GPIbα-selective snake venom toxin, alboaggregin-A. In the present study, it is reported that alboaggregin-A has activity at the collagen receptor GPVI in addition to GPIbα, and evidence is provided that this contributes to protein tyrosine phosphorylation, shape change, and GPIIb-IIIa–dependent aggregation. This may explain why responses to alboaggregin-A are distinct from those to von Willebrand factor– ristocetin.
Regulation of human coagulation factor X gene expression by GATA-4 and the Sp family of transcription factors
Authors: Hung Hsiao-Ling , Pollak Eleanor S. , Kudaravalli Rama D. , Arruda Valder , Chu Kirk , High Katherine A.
Published: July 2002

Serine protease factor Xa plays a critical role in the coagulation cascade. Zymogen factor X is synthesized and modified in the liver. To understand the mechanisms governing the liver-specific expression of factor X, the proximal promoter of human factor X was previously characterized. Two crucial cis elements at −73 and −128 and their cognate binding proteins, HNF-4 and NF-Y, respectively, were identified. In this report, studies are extended to 3 additionalcis elements within the factor X promoter. Using gel mobility shift assays, the liver-enriched protein GATA-4 was identified as the protein binding to the GATA element at −96. GATA-4 transactivates the factor X promoter 28-fold in transient transfection experiments. It was also determined that the Sp family of transcription factors binds 2 DNase I–footprinted sites at −165 and −195. Disruption of Sp protein binding at either site reduces the promoter activity by half. Simultaneous disruption of both sites reduces the promoter activity 8-fold. This is the first report indicating the involvement of GATA-4 in the regulation of clotting factor expression. These observations provide novel insight into mechanisms by which the vitamin K–dependent coagulation factors are regulated.
Redox cycling of diaspirin cross-linked hemoglobin induces G2/M arrest and apoptosis in cultured endothelial cells
Authors: D'Agnillo Felice , Alayash Abdu I.
Published: July 2002

It is hypothesized that oxidative reactions of hemoglobin driven by reactive oxygen species in the vasculature lead to endothelial cell injury or death. Bovine aortic endothelial cells were incubated with diaspirin cross-linked hemoglobin (DBBF-Hb), developed as a hemoglobin-based oxygen carrier, and hydrogen peroxide (H2O2), generated by the glucose oxidase system. The low steady flux of H2O2 oxidizes the ferrous form of DBBF-Hb and drives the redox cycling of ferric and ferryl DBBF-Hb. Cells underwent rounding, swelling and detachment, and accumulated in the G2/M phase of the cell cycle. G2/M arrest preceded the onset of apoptosis as determined by increases in phosphatidylserine (PS) externalization and sub-G1 events. Redox cycling of unmodified hemoglobin also led to G2/M arrest and apoptosis. The rate and extent of DBBF-Hb oxidation correlated with the onset and extent of G2/M arrest and apoptosis and induced significant decreases in soluble reduced thiols. Earlier depletion of glutathione by pretreatment with buthionine sulfoximine rendered cells more susceptible to G2/M arrest and apoptosis. The caspase inhibitor, z-VAD-fmk, had no effect on the induction of G2/M arrest but completely inhibited the subsequent increases in PS externalization and sub-G1 events. Catalase inhibited DBBF-Hb oxidation, the loss of thiols, and the onset of G2/M arrest and apoptosis. These data support a causative role for the ferric–ferryl redox cycle in the development of endothelial cell injury.
Correlation between nicotine-induced inhibition of hematopoiesis and decreased CD44 expression on bone marrow stromal cells
Authors: Khaldoyanidi Sophia , Sikora Lyudmila , Orlovskaya Irina , Matrosova Vera , Kozlov Vladimir , Sriramarao P.
Published: July 2002

This study demonstrates that in vivo exposure to cigarette smoke (CS) and in vitro treatment of long-term bone marrow cultures (LTBMCs) with nicotine, a major constituent of CS, result in inhibition of hematopoiesis. Nicotine treatment significantly delayed the onset of hematopoietic foci and reduced their size. Furthermore, the number of long-term culture-initiating cells (LTC-ICs) within an adherent layer of LTBMCs was significantly reduced in cultures treated with nicotine. Although the production of nonadherent mature cells and their progenitors in nicotine-treated LTBMCs was inhibited, this treatment failed to influence the proliferation of committed hematopoietic progenitors when added into methylcellulose cultures. Bone marrow stromal cells are an integral component of the hematopoietic microenvironment and play a critical role in the regulation of hematopoietic stem cell proliferation and self-renewal. Exposure to nicotine decreased CD44 surface expression on primary bone marrow–derived fibroblastlike stromal cells and MS-5 stromal cell line, but not on hematopoietic cells. In addition, mainstream CS altered the trafficking of hematopoietic stem/progenitor cells (HSPC) in vivo. Exposure of mice to CS resulted in the inhibition of HSPC homing into bone marrow. Nicotine and cotinine treatment resulted in reduction of CD44 surface expression on lung microvascular endothelial cell line (LEISVO) and bone marrow–derived (STR-12) endothelial cell line. Nicotine treatment increased E-selectin expression on LEISVO cells, but not on STR-12 cells. These findings demonstrate that nicotine can modulate hematopoiesis by affecting the functions of the hematopoiesis-supportive stromal microenvironment, resulting in the inhibition of bone marrow seeding by LTC-ICs and interfering with stem cell homing by targeting microvascular endothelial cells.
Epitope mapping of inhibitory antibodies against platelet glycoprotein Ibα reveals interaction between the leucine-rich repeat N-terminal and C-terminal flanking domains of glycoprotein Ibα
Authors: Cauwenberghs Nancy , Vanhoorelbeke Karen , Vauterin Stephan , Westra Douwe F. , Romo Gabriel , Huizinga Eric G. , Lopez José A. , Berndt Michael C. , Harsfalvi Jolàn , Deckmyn Hans
Published: July 2002

The interaction of von Willebrand factor (vWF) with the platelet receptor glycoprotein Ibα (GPIbα) is important for platelet adhesion at high shear stress. Two functionally important antigenic areas within GPIbα were identified through the characterization of 5 new inhibitory anti-GPIb monoclonal antibodies (mAbs). The binding sites of 3 of these anti-GPIb mAbs, which were intercompeting and potently inhibiting shear stress–induced binding of vWF, were mapped within the N-terminal amino acid (aa) 1-59 area by the use of canine-human chimeras. These antibodies, however, had little or no effect (approximately 40% inhibition) on the binding of vWF induced by either botrocetin or ristocetin. On the other hand, the anti-GPIb mAbs 24G10 and 6B4, which blocked GPIb-vWF binding under all conditions examined, bound to 2 different regions of GPIbα, aa 1-81 and aa 201-268, respectively. The epitope for 6B4 was further narrowed by phage display revealing 2 sets of peptide sequences aligning within aa 259-262 and aa 230-242. In the latter region of GPIbα, the gain-of-function platelet-type von Willebrand disease (PT-vWD) mutations have been identified. Alignment was partially confirmed because the binding of 6B4 to recombinant GPIbα fragments carrying either one of the PT-vWD mutations was considerably impaired but not completely abolished. In contrast, mAb 24G10 bound more strongly to mutant PT-vWD GPIbα. However, although 24G10 competed with 6B4 for binding to platelets, it bound to an epitope within aa 1-81 of GPIbα. In conclusion, 2 functionally important areas within GPIbα were identified: one localized within the leucine-rich repeat N-terminal aa 1-59 area and one composed of residues aa 1-81 in close contact with aa 201-268. Moreover, further support is provided for the existence of an intramolecular interaction between the N-terminal flanking (aa 1-81) and C-terminal flanking (aa 201-268) regions.
High-level erythroid-specific gene expression in primary human and murine hematopoietic cells with self-inactivating lentiviral vectors
Authors: Moreau-Gaudry Francois , Xia Ping , Jiang Gang , Perelman Natalya P. , Bauer Gerhard , Ellis James , Surinya Katherine H. , Mavilio Fulvio , Shen Che-Kun , Malik Punam
Published: July 2002

Use of oncoretroviral vectors in gene therapy for hemoglobinopathies has been impeded by low titer vectors, genetic instability, and poor expression. Fifteen self- inactivating (SIN) lentiviral vectors using 4 erythroid promoters in combination with 4 erythroid enhancers with or without the woodchuck hepatitis virus postregulatory element (WPRE) were generated using the enhanced green fluorescent protein as a reporter gene. Vectors with high erythroid-specific expression in cell lines were tested in primary human CD34+ cells and in vivo in the murine bone marrow (BM) transplantation model. Vectors containing the ankyrin-1 promoter showed high-level expression and stable proviral transmission. Two vectors containing the ankyrin-1 promoter and 2 erythroid enhancers (HS-40 plus GATA-1 or HS-40 plus 5-aminolevulinate synthase intron 8 [I8] enhancers) and WPRE expressed at levels higher than the HS2/β-promoter vector in bulk unilineage erythroid cultures and individual erythroid blast-forming units derived from human BM CD34+ cells. Sca1+/lineage− Ly5.1 mouse hematopoietic cells, transduced with these 2 ankyrin-1 promoter vectors, were injected into lethally irradiated Ly5.2 recipients. Eleven weeks after transplantation, high-level expression was seen from both vectors in blood (63%-89% of red blood cells) and erythroid cells in BM (70%-86% engraftment), compared with negligible expression in myeloid and lymphoid lineages in blood, BM, spleen, and thymus (0%-4%). The I8/HS-40–containing vector encoding a hybrid human β/γ-globin gene led to 43% to 113% human γ-globin expression/copy of the mouse α-globin gene. Thus, modular use of erythroid-specific enhancers/promoters and WPRE in SIN-lentiviral vectors led to identification of high-titer, stably transmitted vectors with high-level erythroid-specific expression for gene therapy of red cell diseases.
Targeted disruption of the activating transcription factor 4 gene results in severe fetal anemia in mice
Authors: Masuoka Howard C. , Townes Tim M.
Published: July 2002

Activating transcription factor (ATF) 4 is a ubiquitous basic leucine-zipper transcription factor that is a member of the ATF/cyclic adenosine monophosphate responsive element–binding (CREB) protein family. To determine the in vivo function of ATF4, the ATF4 gene in murine embryonic stem cells was deleted and homozygous mutant mice were generated. ATF4 null fetuses were severely anemic because of an impairment in fetal-liver definitive hematopoiesis; the hematocrit in 15.5-day mutant fetuses was 0.15, whereas that in controls was 0.35. The fetal livers in homozygous ATF4 mutants were pale and hypoplastic. In vitro culture of fetal-liver cells showed fewer hematopoietic progenitors per embryo and a dramatic decrease in the size of progenitor colonies. Culture of primary murine embryonic fibroblasts showed a proliferative defect. These results suggest that ATF4 is critical, in a cell-autonomous manner, for normal cellular proliferation, especially for the high-level proliferation required during fetal-liver hematopoiesis.
Bolus Fluorouracil and Leucovorin With Oxaliplatin as First-Line Treatment in Metastatic Colorectal Cancer
Authors: Ravaioli Alberto , Marangolo Maurizio , Pasquini Enzo , Rossi Andrea , Amadori Dino , Cruciani Giorgio , Tassinari Davide , Oliverio Giovanni , Giovanis Petros , Turci Daniele , Zumaglini Federica , Nicolini Mario , Panzini Ilaria
Published: July 2002

PURPOSE: A phase II trial investigated the activity and toxicity of a bolus administration schedule of oxaliplatin, fluorouracil (5-FU), and leucovorin (LV) therapy in patients with untreated advanced colorectal cancer.

PATIENTS AND METHODS: Forty-five patients in this multicenter, open, nonrandomized study received oxaliplatin 130 mg/m2 on the first day of each course and 5-FU and LV 350 mg/m2 and 20 mg/m2, respectively, as a daily bolus for 5 days, every 21 days, for a maximum of six courses.

RESULTS: Partial responses occurred in 18 patients, giving an intent-to-treat response rate of 40.0%. Median time to response was 12.7 weeks; median duration of response was 18.4 weeks. Median progression-free survival was 5.9 months; median survival was 14 months. The independent prognostic factors for improved overall survival were good performance status and negative carcino-embryonic antigen blood level. Incidences of adverse effects were reduced after the 5-FU dose was reduced to 300 mg/m2. Reversible neurologic toxicity occurred in 44.4% of patients.

CONCLUSION: Bolus administration of oxaliplatin, 5-FU, and LV as first-line therapy for untreated advanced colorectal cancer is efficacious and safe. In addition to a more favorable safety profile, the 300 mg/m2 dosage offered improved dose-intensity compared with the initial dosage.
Hypertensive Disorders and Cardiovascular Severe Maternal Morbidity in the US, 2015-2019
Authors: Malhamé Isabelle , Nerenberg Kara , McLaughlin Kelsey , Grandi Sonia M. , Daskalopoulou Stella S. , Metcalfe Amy
Published: October 2024

Importance

The incidence of severe maternal morbidity (SMM)—and particularly cardiovascular SMM (cvSMM), the first cause of pregnancy-related mortality—has been rising in North America. Although hypertensive disorders of pregnancy (HDP) are common, their association with cvSMM specifically remains unclear.

Objective

To assess the association between individual subtypes of HDP and cvSMM, in addition to overall SMM, in a large, nationally representative sample.

Design, Setting, and Participants

A population-based cohort study using the United States National Inpatient Sample was conducted. Individuals with obstetric deliveries between 2015 and 2019 were included. Data analysis was performed from October 2023 to February 2024.

Exposure

HDP subtypes included gestational hypertension, chronic hypertension, preeclampsia without severe features, severe preeclampsia, and HELLP (hemolysis, elevated liver enzymes, and low platelet) syndrome.

Main Outcomes and Measures

The primary outcome was a composite of cvSMM (including conditions such as pulmonary edema, stroke, and acute myocardial infarction) and the secondary outcome was a composite of overall SMM (including cvSMM and other conditions such as respiratory failure, severe postpartum hemorrhage, and sepsis). Adjusted risk ratios (aRRs) for the association between HDP subtypes and the outcomes were estimated using modified Poisson regression models adjusted for demographic and clinical characteristics.

Results

Among 15 714 940 obstetric deliveries, 2 045 089 (13.02%) had HDP, 23 445 (0.15%) were affected by cvSMM, and 282 160 (1.80%) were affected by SMM. The mean (SD) age of the cohort was of 29 (6) years. The incidence of cvSMM was higher in participants with HDP than those without HDP (0.48% [9770 of 2 045 089] vs 0.10% [13 680 of 13 669 851]; P < .001). Participants with HELLP syndrome had the highest risk for cvSMM (aRR, 17.55 [95% CI, 14.67-21.01]), followed by severe preeclampsia (aRR, 9.11 [95% CI, 8.26-10.04]), and chronic hypertension (aRR, 3.57 [95% CI, 3.15-4.05]). Although HDP subtypes were also associated with overall SMM, the association with HELLP syndrome (aRR, 9.94 [95% CI, 9.44-10.45]), severe preeclampsia (aRR, 3.66 [95% CI, 3.55-3.78]), and chronic hypertension (aRR, 1.96 [95% CI, 1.88-2.03]) was attenuated compared with cvSMM.

Conclusions and Relevance

In this cohort study, a graded relationship by severity characterized the association between HDP and cvSMM. Although all HDP subtypes were associated with an increased risk of overall SMM, the risk was more pronounced for cvSMM.
Transforming science communication through storytelling
Authors: Guglielmi Giorgia , Petersen Emil , Alvarez Laura , Zacharioudaki Eva , Morais Ana , Dorado‐Ladera Esther , Kaunisto Mari
Published: October 2024

Science communication is an important skill. It is easier for nonacademic audiences to remember stories that resonate with their imagination rather than facts and figures. To help early‐career researchers develop their skills, the EU‐LIFE Science Communications Working Group (SCWG) developed a training course based on the experience from previous workshops held at a research institute in Denmark. The stories crafted in the workshops proved impactful, with some integrated into broader campaigns and featured in science magazines. The initiative holds potential for transformative change, helping researchers promote their findings and increasing awareness of emerging research topics among the public. Recently, the initiative has been customized for a summer school aimed at medical doctors pursuing a PhD, marking a step forward in the SCWG's mission to equip researchers with essential communication skills.
Mechanochemical Synthesis and Characterization of Nanostructured ErB4 and NdB4 Rare‐Earth Tetraborides
Authors: Boztemur Burçak , Kaya Faruk , Derin Bora , Öveçoğlu Mustafa Lütfi , Li Ju , Ağaoğulları Duygu
Published: October 2024

Rare‐earth borides have become very popular in recent decades with high mechanical strength, melting point, good corrosion, wear, and magnetic behavior. However, the production of these borides is very challenging and unique. The production of ErB4 and NdB4 nanopowders via mechanochemical synthesis (MCS) is reported in this study first time in the literature. Er2O3 or Nd2O3, B2O3, and Mg initial powders are mechanically alloyed for different milling times to optimize the process. Rare‐earth borides with MgO phases are synthesized, then MgO is removed with HCl acid. The nanostructured rare‐earth tetraboride powders are analyzed using X‐ray diffraction (XRD). Based on the XRD, ErB4 powders are produced successfully at the end of the 5 h milling. However, the NdB4 phase does not occur as the stoichiometric ratio, so the B2O3 amount is decreased to nearly 35 wt%. When the amount of B2O3 is decreased to 20 wt%, NdB4 and NdB6 phases are 50:50 according to the Rietveld analysis. However, a homogenous NdB4 phase is obtained with 30 wt% loss of B2O3. The average particle sizes of ErB4 and NdB4 powders are nearly 100.4 and 85.6 nm, respectively. The rare‐earth tetraborides exhibit antiferromagnetic‐to‐paramagnetic‐like phase transitions at 18 and 8.53 K, respectively.
1D Crystallographic Etching of Few‐Layer WS2
Authors: Li Shisheng , Lin Yung‐Chang , Chiew Yiling , Dai Yunyun , Ning Zixuan , Zhang Yaming , Nakajima Hideaki , Lim Hong En , Wu Jing , Neitoh Yasuhisa , Okazaki Toshiya , Sun Yang , Sun Zhipei , Suenaga Kazu , Sakuma Yoshiki , Tsukagoshi Kazuhito , Taniguchi Takaaki
Published: October 2024

Layer number‐dependent band structures and symmetry are vital for the electrical and optical characteristics of 2D transition metal dichalcogenides (TMDCs). Harvesting 2D TMDCs with tunable thickness and properties can be achieved through top‐down etching and bottom‐up growth strategies. In this study, a pioneering technique that utilizes the migration of in situ generated Na‐W‐S‐O droplets to etch out 1D nanotrenches in few‐layer WS2 is reported. 1D WS2 nanotrenches are successfully fabricated on the optically inert bilayer WS2, showing pronounced photoluminescence and second harmonic generation signals. Additionally, the modulation of inkjet‐printed Na2WO4‐Na2SO4 particles to switch between the etching and growth modes by manipulating the sulfur supply is demonstrated. This versatile approach enables the creation of 1D nanochannels on 2D TMDCs. The research presents exciting prospects for the top‐down and bottom‐up fabrication of 1D‐2D mixed‐dimensional TMDC nanostructures, expanding their use for electronic and optoelectronic applications.
Protection of Fe Single‐Atoms by Fe Clusters for Chlorine‐Resistant Oxygen Reduction Reaction
Authors: Rao Peng , Liu Yurong , Shi Xiaodong , Yu Yanhui , Zhou Yu , Li Ruisong , Liang Ying , Wu Daoxiong , Li Jing , Tian Xinlong , Miao Zhengpei
Published: October 2024

Direct seawater zinc‐air batteries (S‐ZABs), with their inherent properties of high energy density, intrinsic safety, and low cost, present a compelling avenue for the development of energy storage technology. However, the presence of chloride ions in seawater poses challenges to their air electrode, resulting in sluggish reaction kinetics and poor stability for the oxygen reduction reaction (ORR). Herein, Fe atomic clusters (ACs) decorated Fe single‐metal atoms (SAs) catalyst (FeSA‐FeAC/NC) is prepared using a plasma treatment strategy. The aberration‐corrected transmission electron microscope images confirm the successful construction of Fe SAs surrounding Fe ACs, which delivers robust ORR activity with a half‐wave potential of 0.886 V in alkaline seawater electrolyte. When utilized as the cathode catalyst in assembled S‐ZABs, the battery demonstrates excellent discharge performance, achieving a peak power density of 222 mW cm−2, which is 2.3 times higher than Pt/C based S‐ZABs. Moreover, density functional theory calculations unveil that the synergy effect between the Fe ACs and SAs not only reduces the spin‐down d‐band center in the Fe SAs, but also efficiently suppresses Cl−1 adsorption on Fe SAs due to their strong Cl−1 absorption ability of the Fe ACs, thereby enhancing both the activity and stability of the catalyst.
Strong and Ultrahigh Temperature‐Resistant Metal Oxide Nanobelt Aerogels
Authors: Wang Xiaodong , Wang Yijun , Zhang Ze , Zhao Zhiyang , Liu Ting , Tian Yulin , Zhang Xiaoxue , Burkule Snigdha , Malfait Wim J. , Zhao Shanyu , Zhang Zhihua , Shen Jun
Published: October 2024

Metal oxide aerogels, inorganic cousins of the highly commercialized metalloid oxide silica aerogels, exhibit distinct properties specific to each type. Nevertheless, they share a common challenge with silica aerogels—brittleness and low mechanical strength due to their particulate necklace‐like structure. In contrast, polymer aerogels often boast significantly enhanced mechanical properties thanks to their nanofibrillated networks. To enhance the mechanical properties of metal oxide aerogels, the metal oxide formation with a polymeric nanostructure is micro‐templated. This method transforms the necklace‐like particulate microstructure of metal oxide aerogels (e.g., Al2O3 Cr2O3, and Fe2O3) into a polymer‐like nanobelt structure. Remarkably, even after removing the polymer template through calcination at 600 °C, the nanobelt structure remains intact. These metal oxide nanobelt (MNB) aerogels exhibit exceptional compressibility while retaining their mesoporous structure. As a demonstration, the resulting Al‐MNB aerogel can withstand compression up to 80% strain without fracturing while preserving its porous nanobelt structure and a high specific surface area of 228 m2 g−1 and a pore volume of 0.7 cm3 g−1 after heat treatment at 1300 °C. This work introduces an innovative strategy for creating a distinctive polymer‐like nanobelt microstructure, paving the way for novel applications of metal oxide aerogels with unique structures and enhanced performance.