bluuebunny/crossref_metadata_2025 huggingface dataset:
What does mos do in oocytes and somatic cells?
Authors: Sagata Noriyuki
Published: February 2005

Mos, a protein kinase, is specifically expressed and functions during meiotic maturation (or G2/M progression) of vertebrate oocytes. When expressed ectopically, however, it can also readily induce oncogenic transformation (or uncontrolled G1/S transitions) in somatic cells. In both of these cell types, Mos activates mitogen‐activated protein kinase (MAPK), which seems largely to mediate its different functions in both oocyte maturation and cellular transformation. In oocyte maturation, the Mos‐MAPK pathway probably serves to activate and stabilize M‐phase promoting factor (MPF) (possibly by inhibiting some negative regulator(s) of this factor), while in cellular transformation, it seems to stabilize and activate the nuclear oncoprotein c‐Fos as well as to induce transcription of its gene. Thus, the different functions of Mos in oocytes and somatic cells may arise chiefly from its different MAPK‐mediated targets in the respective cell types. This review discusses the cellular basis that may enable Mos to act differently in oocytes and somatic cells.
Histone acetylation: A possible mechanism for the inheritance of cell memory at mitosis
Authors: Jeppesen Peter
Published: February 2005

Immunofluorescent labelling demonstrates that human metaphase chromosomes contain hyperacetylated histone H4. With the exception of the inactive X chromosome in female cells, where the bulk of histone H4 is under‐acetylated, H4 hyperacetylation is non‐uniformly distributed along the chromosomes and clustered in cytologically resolvable chromatin domains that correspond, in general, with the R‐bands of conventional staining. The strongest immunolabelling is often found in T‐bands, the subset of intense R‐bands having the highest GC content. The majority of mapped genes also occurs in R‐band regions, with the highest gene density in T‐bands. These observations are consistent with a model in which hyperacetylation of histone H4 marks the position of potentially active gene sequences on metaphase chromosomes. Since acetylation is maintained during mitosis, progeny cells receive an imprint of the histone H4 acetylation pattern that was present on the parental chromosomes before cell division. Histone acetylation could provide a mechanism for propagating cell memory, defined as the maintenance of committed states of gene expression through cell lineages.
Axis specification in animal development
Authors: Goldstein Bob , Freeman Gary
Published: February 2005

Axis specification is the first step in defining specific regions of the developing embryo. Embryos exploit asymmetries, either pre‐existing in the egg or triggered by external cues, to establish embryonic axes. The axial information is then used to generate regional differences within the embryo. In this review, we discuss experiments in animals which address three questions: whether the unfertilized egg is constructed with pre‐determined axes, what cues are used to specify the embryonic axes, and how these cues are interpreted to generate the initial regional differences within the embryo. Based on mapping the data onto an animal phylogeny, we then propose a scenario for how this primary developmental decision occurred in ancestral metazoans.
Genetic depletion reveals an essential role for an SR protein splicing factor in vertebrate cells
Authors: Mount Stephen M.
Published: February 2005

SR proteins are essential for the splicing of messenger RNA precursors in vitro, where they also alter splice site selection in a concentration‐dependent manner. Although experiments involving overexpression or dominant mutations have confirmed that these proteins can influence RNA processing decisions in vivo, similar results with loss‐of‐function mutations have been lacking. Now, a system for genetic depletion of the chicken B cell line DT40 has revealed that the SR protein ASF/SF2 (alternative splicing factor/splicing factor 2) is essential for viability in these cells(1). This study opens the way for a complete functional dissection of this protein, and other SR proteins, in vivo.
Developmental control of cell division in leech embryos
Authors: Bissen Shirley T.
Published: February 2005

During embryogenesis, cell division must be spatially and temporally regulated with respect to other developmental processes. Leech embryos undergo a series of unequal and asynchronous cleavages to produce individually recognizable cells whose lineages, developmental fates and cell cycle properties have been characterized. Thus, leech embryos provide an opportunity to examine the regulation of cell division at the level of individual well‐characterized cells within a community of different types of cells. Isolation of leech homologues of some of the highly conserved regulators of the cell division cycle, and characterization of their patterns of maternal and zygotic expression, indicate that the cell divisions of early leech embryos are regulated by cell type‐specific mechanisms. These studies with leech embryos contribute to the emerging appreciation of the diverse mechanisms by which animals regulate cell division during early development.
Evolution and development — the nematode vulva as a case study
Authors: Sommer Ralf J.
Published: February 2005

To understand how morphological characters change during evolution, we need insight into the evolution of developmental processes. Comparative developmental approaches that make use of our fundamental understanding of development in certain model organisms have been initiated for different animal systems and flowering plants. Nematodes provide a useful experimental system with which to investigate the genetic and molecular alterations underlying evolutionary changes of cell fate specification in development, by comparing different species to the genetic model system Caenorhabditis elegans. In this review, I will first discuss the different types of evolutionary alterations seen at the cellular level by focusing mainly on the analysis of vulva development in different species. The observed alterations involve changes in cell lineage, cell migration and cell death, as well as induction and cell competence. I then describe a genetic approach in the nematode Pristionchus pacificus that might identify those genetic and molecular processes that cause evolutionary changes of cell fate specification.
What do linker histones do in chromatin?
Authors: Wolffe Alan P. , Khochbin Saadi , Dimitrov Stefan
Published: February 2005

Knockout experiments in Tetrahymena show that linker histone H1 is not essential for nuclear assembly or cell viability. These results, together with a series of biochemical and cell biological observations, challenge the existing paradigm that requires linker histones to be a key organizing component of higher‐order chromatin structure. The H1 Knockouts also reveal a much more subtle role for H1. Instead of acting as a general transcriptional repressor, H1 is found to regulate a limited number of specific genes. Surprisingly, H1 can both activate and repress transcription. We discuss how this architectural protein might accomplish this important regulatory role.
Illuminating flowers: CONSTANS induces LEAFY expression
Authors: Blázquez Miguel A.
Published: February 2005

Higher plants must undergo a major developmental switch, the transition to flowering, if they are to successfully complete their life cycle. In many plants, the crucial decision of when to begin to produce flowers is primarily controlled by environmental signals. The process of floral induction involves the integration of the activities of two types of genes: those that control flowering time as a response to the environment as well as an endogenous clock, and those that determine the floral identity of the cells. The first direct link between these two classes of genes has now been demonstrated(1). Forced expression of CONSTANS, a flowering‐time gene, promotes flowering through the transcriptional activation of LEAFY, a flower‐meristem‐identity gene.
Fish are like flies are like frogs: Conservation of dorsal‐ventral patterning mechanisms
Authors: Holley Scott A. , Ferguson Edwin L.
Published: February 2005

Genetic analysis of Drosophila has shown that a morphogenetic gradient of the Transforming Growth Factor‐β family member dpp patterns the embryonic dorsalventral axis. Molecular and embryological evidence from Xenopus has strongly suggested a similar role for Bmp‐4, the dpp homolog, in patterning the dorsalventral axis of chordates. A recent report has now identified mutations in two genes, dino and swirl, that disrupt dorsal‐ventral patterning in the zebrafish Danio rerio(1). Characterization of these mutations parallels findings from Drosophila, thus establishing a genetic framework for the analysis of dorsalventral patterning in a vertebrate.
Dynamic organisation of intermediate filaments and associated proteins during the cell cycle
Authors: Foisner Roland
Published: February 2005

Intermediate filaments, which form the structural framework of both the cytoskeleton and the nuclear lamina in most eukaryotic cells, have been found to be highly dynamic structures. A continuous exchange of subunit proteins at the filament surface and a stabilisation of soluble subunits by chaperone‐type proteins may modulate filament structure and plasticity. Recent studies on the cell cycle‐dependent interaction of intermediate filaments with associated proteins, and a detailed analysis of intermediate filament phosphorylation in defined subcellular locations at various stages of mitosis, have brought new insights into the molecular mechanisms involved in the mitotic reorganisation of intermediate filaments. Some of these studies have allowed new speculations about the possible cellular functions of cytoplasmic intermediate filaments, and increased our understanding of the specific functions of the lamins and the lamina‐associated membrane proteins in the post‐mitotic reassembly of the nucleus.
Insulin second messengers
Authors: Strålfors Peter
Published: February 2005

The molecular pathways for insulin's signal transduction from its cell surface receptor to the cell's interior metabolic machinery remain in many ways uncharted. Lately two molecules have been proposed as second messengers transducing the insulin signal into the target cell. One is a phospholigosaccharide/inositolphosphoglycan and the other is diacylglycerol, both deriving from the same plasma membrane glycolipid, which is hydrolysed in response to insulin treatment. The phospho‐oligosaccharide appears to mediate many metabolic effects of insulin through control of the phosphorylation state of key regulatory metabolic enzymes. Diacylglycerol may mediate insulin's stimulation of glucose transport over the plasma membrane. The glycolipid precursor of these putative second messengers, as well as the receptor for insulin, appear to be localized in caveolae microdomains of the plasma membrane, and glucose transporters accumulate in caveolae in response to insulin treatment, suggesting a focal role for caveolae in insulin signalling.
The cambrian evolutionary ‘explosion’ recalibrated
Authors: Fortey Richard A. , Briggs Derek E. G. , Wills Matthew A.
Published: February 2005

The sudden appearance in the fossil record of the major animal phyla apparently records a phase of unparalleled, rapid evolution at the base of the Cambrian period, 545 Myr ago. This has become known as the Cambrian evolutionary ‘explosion’, and has fuelled speculation about unique evolutionary processes operating at that time. The acceptance of the palaeontological evidence as a true reflection of the evolutionary narrative has been criticised in two ways: from a reappraisal of the phylogenetic relationships of the early fossils, and from predicitions of molecular divergence times, based on six appropriate metazoan genes. Phylogenetic analysis of the arthropods implies an earlier, Precambrian history for most clades, and hence an extensive period of cladogenesis unrecorded by fossils. A similar argument can be applied to molluscs, lophophorates and deuterostomes. Molecular evidence implies divergence between clades to at least 1000 Myr ago. The apparent paradox between the sudden appearance of recognisable metazoans and their extended evolutionary history might be explained by a sudden Cambrian increase in body size, which was accompanied by skeletisation. A new paradigm suggests that the ‘explosion’ in the record may have been decoupled from the evolutionary innovation.
The IRS‐signalling system during insulin and cytokine action
Authors: Yenush Lynne , White Morris F.
Published: February 2005

The discovery of the first intracellular substrate for insulin, IRS‐1, redirected the field of diabetes research and has led to many important advances in our understanding of insulin action. Detailed analysis of IRS‐1 demonstrates structure/function relationships for this modular docking molecule, including mechanisms of substrate recognition and signal propagation. Recent work has also identified other structurally similar molecules, including IRS‐2, the Drosophila protein, DOS, and the Grb2‐binding protein, Gab1, suggesting that this intracellular signalling strategy is conserved evolutionarily and is utilized by an expanding number of receptor systems. In fact, IRS‐1 itself has been shown to be important in other growth factor and cytokine signalling systems, including growth hormone and several interleukins. Analysis of mice lacking IRS‐1 confirms an important physiological role for this protein in glucose metabolism and general cell growth in the intact animal. Disregulation of the signalling pathways integrated by the IRS proteins may contribute to the pathophysiology of non‐insulin‐dependent diabetes mellitus or other diseases.
Collectins: Collectors of microorganisms for the innate immune system
Authors: Lu Jinhua
Published: February 2005

Collections are a group of multimeric proteins mostly consisting of 9–18 polypeptides organised into either ‘bundle‐of‐tulips’ or ‘X‐like’ overall structures. Each polypeptide contains a short N‐terminal segment followed by a collagen‐like sequence and then by a C‐terminal lectin domain. A collectin molecule is assembled from identical or very similar polypeptides by disulphide bonds at the N‐terminal segment, formation of triple helices in the collagen‐like region and clusters of three lectin domains at the peripheral ends of triple helices. These proteins can bind to sugar residues on microorganisms via the peripheral lectin domains and subsequently interact, via the collagen‐like triple‐helices, with receptor(s) on phagocytes and/or the complement system to bring about the killing and clearance of the targets without the involvement of antibodies. The collectins can also bind to phagocyte receptor(s) to enhance phagocytosis mediated by other phagocytic receptors. Lack, or low levels, of collectin expression can lead to higher susceptibility to infections, especially during childhood when specific immunity has not fully developed. Therefore, the collectins play important roles in the enhancement of innate immunity.
The function of inositol high polyphosphate binding proteins
Authors: Fukuda Mitsunori , Mikoshiba Katsuhiko
Published: February 2005

The inositol phosphate metabolism network has been found to be much more complex than previously thought, as more and more inositol phosphates and their metabolizing enzymes have been discovered. Some of the inositol phosphates have been shown to have biological activities, but little is known about their signal transduction mechanisms except for that of inositol 1,4,5‐trisphosphate. The recent discovery, however, of a number of binding proteins for inositol high polyphosphate [inositol 1,3,4,5‐tetrakisphosphate (IP4), inositol 1,3,4,5,6‐pentakisphosphate, or inositol hexakisphosphate] enables us to speculate on the physiological function of these compounds. In this article we focus on two major issues: (1) the roles of inositol high polyphosphates in vesicular trafficking, especially exocytosis, and (2) pleckstrin homology domaincontaining IP4 binding proteins involved in the Ras signaling pathway.
Controlling the molecular motor of neutrophil chemotaxis
Authors: Hallett M. B.
Published: February 2005

Our defence against microbes depends largely on the ability of neutrophils to migrate from the blood stream to sites of infection. Although the ability of animal cells to move may be primitive, and also fundamental for a number of phenomena in biology, the cellular mechanism by which neutrophils are able to move rapidly towards the infection remains an enigma. Even though the structures of the receptors involved have been sequenced and many of the molecules involved in neutrophil adherence and traction identified, the essential mechanisms that control and regulate the neutrophil motor remain obscure. Here, an outline of the fundamental inadequacies in our current understanding is given, along with some recent developments that promise to produce some significant advances.
Coxsackieviruses and diabetes
Authors: Ramsingh Arlene I. , Chapman Nora , Tracy Steven
Published: February 2005

Insulin‐dependent diabetes mellitus (IDDM) is an autoimmune disease whose etiology is complex. Both genetic susceptibility, which is polygenic, and environmental factors, including virus infections, appear to be involved in the development of IDDM. In this review, we have tried to balance the discussion of diabetes by examining both immunological and virological perspectives. Several mouse models, including viral and non‐viral models, have been used to study diabetes. For this review, we include lessons gleaned from the non‐obese diabetic (NOD) mouse and from mouse models of coxsackievirus‐ and encephalomyocarditis‐virus‐induced diabetes. Finally, we present a multi‐stage model in which several viral infections, including the coxsackieviruses, are postulated to play a role in the autoimmune destruction of pancreatic beta cells.
Complete sequence of a Rhizobium plasmid carrying genes necessary for symbiotic association with the plant host
Authors: Kiss Ernö , Kondorosi Ádám
Published: February 2005

The soil bacteria rhizobia have the capacity to establish nitrogen‐fixing symbiosis with their leguminous host plants. In most Rhizobium species the genes for nodule development and nitrogen fixation have been localized on large indigenous plasmids that are transmissible, allowing lateral transfer of symbiotic functions. A recent paper reports on the complete sequencing of the symbiotic plasmid pNGR234a from Rhizobium species NGR234(1), revealing not only putative new symbiotic genes but also possible mechanisms for evolution and lateral dispersal of symbiotic nitrogen‐fixing abilities among rhizobia.
Vertebrate head induction by anterior primitive endoderm
Authors: Bouwmeester Tewis , Leyns Luc
Published: February 2005

In vertebrates the antero‐posterior organization of the embryonic body axis is thought to result from the activity of two separate centers, the head organizer and the trunk organizer, as operationally defined by Spemann in the 1920s. Current molecular studies have supported the existence of a trunk organizer activity while the presence of a distinct head inducing center has remained elusive. Mainly based on analyses of headless mutants in mice, it has been proposed that the anterior axial mesoderm plays a determining role in head induction. Recent gain‐ and loss‐of‐function studies in various organisms, however, provide compelling evidence that a largely ignored region, the anterior primitive endoderm, specifies rostral identity. In this review we discuss the emerging concept that the anterior primitive endoderm, rather than the prechordal plate mesoderm, induces head development in the vertebrate embryo.
Problems and paradigms: Multifunctional proteins suggest connections between transcriptional and post‐transcriptional processes
Authors: Ladomery Michael
Published: February 2005

Recent findings indicate that substantial cross‐talk may exist between transcriptional and post‐transcriptional processes. Firstly, there are suggestions that specific promoters influence the post‐transcriptional fate of transcripts, pointing to communication between protein complexes assembled on DNA and nascent pre‐mRNA. Secondly, an increasing number of proteins appear to be multifunctional, participating in transcriptional and post‐transcriptional events. The classic example is TFIIIA, required for both the transcription of 5S rRNA genes and the packaging of 5S rRNA. TFIIIA is now joined by the Y‐box proteins, which bind DNA (transcription activation and repression) and RNA (mRNA packaging). Furthermore, the tumour suppressor WT1, at first thought to be a typical transcription factor, may also be involved in splicing; conversely, hnRNP K, a bona fide pre‐mRNA‐binding protein, appears to be a transcription factor. Other examples of multifunctional proteins are mentioned: notably PTB, Sxl, La and PU.1. It is now reasonable to assert that some proteins, which were first identified as transcription factors, could just as easily have been identified as splicing factors, hnRNP, mRNP proteins and vice versa. It is no longer appropriate to view gene expression as a series of compartmentalised processes; instead, multifunctional proteins are likely to co‐ordinate different steps of gene expression.
Hypothesis: L‐selectin: A novel receptor for lipopolysaccharide and its potential role in bacterial sepsis
Authors: Malhotra Rajneesh , Bird Michael I.
Published: February 2005

The activation of leukocytes by bacterial cell wall lipopolysaccharide (LPS) contributes to the pathogenesis of septic shock. It is well established that, in the presence of plasma LPS‐binding protein (LBP), LPS binds with high affinity to CD14. The binding of LPS to CD14 has been associated with the activation of cells, although available evidence indicates that CD14 itself does not transduce intracellular signalling. The physiological function of this interaction is to promote host defense mechanisms of cells to combat the infection and clear LPS from the circulation. At higher concentrations of LPS, however, the activation of cells can take place in the absence of LBP and CD14, presumably through a distinct low‐affinity signalling LPS receptor. On the evidence published by us and others, we propose that in neutrophils, and possibly other leukocytes, L‐selectin can act as a low‐affinity LPS receptor.
Zyxin: Zinc fingers at sites of cell adhesion
Authors: Beckerle Mary C.
Published: February 2005

Zyxin is a low abundance phosphoprotein that is localized at sites of cell‐substratum adhesion in fibroblasts. Zyxin displays the architectural features of an intracellular signal transducer. The protein exhibits an extensive proline‐rich domain, a nuclear export signal and three copies of the LIM motif, a double zinc‐finger domain found in many proteins that play central roles in regulation of cell differentiation. Zyxin interacts with α‐actinin, members of the cysteine‐rich protein (CRP) family, proteins that display Src homology 3 (SH3) domains and Ena/VASP family members. Zyxin and its partners have been implicated in the spatial control of actin filament assembly as well as in pathways important for cell differentiation. Based on its repertoire of binding partners and its behavior, zyxin may serve as a scaffold for the assembly of multimeric protein machines that function in the nucleus and at sites of cell adhesion.
Proliferating cell nuclear antigen: More than a clamp for DNA polymerases
Authors: Jónsson Zophonías O. , Hübscher Ulrich
Published: February 2005

DNA metabolic events such as replication, repair and recombination require the concerted action of several enzymes and cofactors. Nature has provided a set of proteins that support DNA polymerases in performing processive, accurate and rapid DNA synthesis. Two of them, the proliferating cell nuclear antigen and its adapter protein replication factor C, cooperate to form a moving platform that was initially thought of only as an anchor point for DNA polymerases δ and ε. It now appears that proliferating cell nuclear antigen is also a communication point between a variety of important cellular processes including cell cycle control, DNA replication, nucleotide excision repair, post‐replication mismatch repair, base excision repair and at least one apoptotic pathway. The dynamic movement of proliferating cell nuclear antigen on and off the DNA renders this protein an ideal communicator for a variety of proteins that are essential for DNA metabolic events in eukaryotic cells.
Multifunctional plasma membrane redox systems
Authors: Medina Miguel Ángel , Castillo‐Olivares Antonio Del , De Castro Ignacio NúÑez
Published: February 2005

All the biological membranes contain oxidoreduction systems actively involved in their bioenergetics. Plasma membrane redox systems seem to be ubiquitous and they have been related to several important functions, including not only their role in cell bioenergetics, but also in cell defense through the generation of reactive oxygen species, in iron uptake, in the control of cell growth and proliferation and in signal transduction. In the last few years, an increasing number of mechanistic and molecular studies have deeply widened our knowledge on the function of these plasma membrane redox systems. The aim of this review is to summarize what is currently known about the components and physiological roles of these systems.
Signaling activation and repression of RNA polymerase II transcription in yeast
Authors: Reece Richard J. , Platt Adam
Published: February 2005

Activators of RNA polymerase II transcription possess distinct and separable DNA‐binding and transcriptional activation domains. They are thought to function by binding to specific sites on DNA and interacting with proteins (transcription factors) binding near to the transcriptional start site of a gene. The ability of these proteins to activate transcription is a highly regulated process, with activation only occurring under specific conditions to ensure proper timing and levels of target gene expression. Such regulation modulates the ability of transcription factors either to bind DNA or to interact with the transcriptional machinery. Here we discuss recent advances in our understanding of these mechanisms of transcriptional regulation in yeast.
Calpains: Intact and active?
Authors: Johnson Gail V. W. , Guttmann Rodney P.
Published: February 2005

Calpains are a family of calcium‐dependent thiol‐proteases which are proposed to be involved in many physiological processes as well as pathological conditions. Calpains are likely to be involved in processing of numerous enzymes and cytoskeletal components, thereby linking their activity to a variety of intracellular events. Although widely studied, the precise mechanism(s) involved in calpain activation and activity in vivo remain poorly understood. Initial studies suggested that calpain exists primarily as an inactive proenzyme that required autolytic cleavage for activation. It was also hypothesized that calpain associated with membrane phospholipids, serving to increase calcium sensitivity, facilitating autolytic conversion and thus activating the enzyme. These hypotheses, however, have not been universally accepted and there is increasing evidence that intact, non‐autolyzed calpain is the physiologically active calpain form.
Primary rectus abdominis myocutaneous flap for repair of perineal and vaginal defects after extended abdominoperineal resection
Authors: Bell S W , Dehni N , Chaouat M , Lifante J C , Parc R , Tiret E
Published: February 2005

Background

Significant morbidity can result from perineal wounds, particularly after radiotherapy and extensive resection for cancer. Myocutaneous flaps have been used to improve healing. The purpose of this study was to evaluate the morbidity and results of primary rectus abdominis myocutaneous flap reconstruction of the vagina and perineum after extended abdominoperineal resection.

Methods

Thirty-one consecutive patients undergoing one-stage rectus abdominis myocutaneous flap reconstruction of extensive perineal wounds were studied prospectively. Twenty-six patients had surgery for recurrent or persistent epidermoid anal cancer or low rectal cancer, and 21 had high-dose preoperative radiotherapy.

Results

Three weeks after the operation, complete healing of the perineal wound was seen in 27 of the 31 patients. There were nine flap-related complications including three patients with partial flap necrosis, two with vaginal stenosis, one with vaginal scarring, one with small flap disunion and two with weakness of the anterior abdominal wall. There were no unhealed wounds at the completion of follow-up (median 9 months).

Conclusion

The transpelvic rectus abdominis myocutaneous flap for the reconstruction of large perineal and vaginal wounds achieves wound healing with only moderate morbidity in the majority of patients after extensive abdominoperineal resection with or without radiotherapy.
Nipple–areola complex reconstruction using badge flap and intradermal tattooing
Authors: Chen S-G , Chiu T-F , Su W-F , Chou T-D , Chen T-M , Wang H-J
Published: February 2005

A useful technique for breast surgeons
Successful urgent endovascular surgery for symptomatic subclavian artery aneurysmal compression of the trachea
Authors: Bates Mark C. , AbuRahma Ali F. , Crotty Bradley
Published: February 2005

The purpose of this study is to report the progress of a patient who entered the hospital with symptomatic tracheal compression from a large right subclavian artery aneurysm that was treated with a self‐expanding stent graft. The patient was at increased risk for traditional surgery, thus endovascular isolation of the aneurysm was felt to be reasonable. A flexible self‐expanding stent graft was placed via a brachial artery cutdown and common femoral access without complication. The symptoms improved and the patient remained asymptomatic at 2‐year follow‐up with serial CT scan confirmation of aneurysm regression. This unusual case illustrates that endovascular decompression of an aneurysm may have some benefit in alleviating subacute symptoms of extrinsic encroachment into other vital structures. Technical and clinical success was achieved with the stent graft deployment and this seems to be a reasonable alternative to surgery in such patients. Catheter Cardiovasc Interv 2005;64:291–295. © 2005 Wiley‐Liss, Inc.
Rare case of pulmonary arteriovenous fistula simulating residual defect after transcatheter closure of patent foramen ovale for recurrent paradoxical embolism
Authors: Peters Bjoern , Ewert P. , Schubert S. , Abdul‐Khaliq H. , Lange P.E.
Published: February 2005

We report on a patient suffering from recurrent cerebrovascular events despite previous transcatheter closure of persistent foramen ovale (PFO) with a Helex occluder. There was evidence of persistent left‐to‐right atrial shunt shown by transesophageal contrast echocardiography and the patient was admitted to our institution for interventional closure of the supposed residual defect. However, the PFO was completely closed by the device and left pulmonary artery injections showed a pulmonary arteriovenous fistula in the left lower lobe. This rare malformation may well explain the recurrent paradoxical embolism. Transcatheter fistula closure with coils was performed successfully. This case underlines that the existence of an isolated pulmonary arteriovenous fistula as a right‐to‐left shunt in patients with cryptogenic stroke should not be overlooked, even if a PFO is present and pulmonary arteriovenous fistula is not suggested by the initial physical findings or chest X‐ray. Catheter Cardiovasc Interv 2005;64:348–351. © 2005 Wiley‐Liss, Inc.
Submassive pulmonary embolism and paradoxical embolic stroke treated with percutaneous rheolytic thrombectomy and closure of the patent foramen ovale
Authors: Iskander Ayman , Nayak Atasu , Chauhan Manish S.
Published: February 2005

The presence of patent foramen ovale (PFO) in patients with large pulmonary emboli (PE) is associated with an increased risk of stroke and mortality. Many patients are ineligible to receive thrombolytic therapy. We present a patient with bilateral PE and cryptogenic stroke who was treated effectively with rheolytic thrombectomy with AngioJet, PFO closure with CardioSeal device, and placement of an inferior vena cava filter. Catheter Cardiovasc Interv 2005;64:356–360. © 2005 Wiley‐Liss, Inc.
Can Weakly Coordinating Anions Stabilize Mercury in Its Oxidation State +IV?
Authors: Riedel Sebastian , Straka Michal , Kaupp Martin
Published: February 2005

While the thermochemical stability of gas‐phase HgF4 against F2 elimination was predicted by accurate quantum chemical calculations more than a decade ago, experimental verification of “truly transition‐metal” mercury(IV) chemistry is still lacking. This work uses detailed density functional calculations to explore alternative species that might provide access to condensed‐phase HgIV chemistry. The structures and thermochemical stabilities of complexes HgIVX4 and HgIVF2X2 (X−=AlF4−, Al2F7−, AsF6−, SbF6−, As2F11−, Sb2F11−, OSeF5−, OTeF5−) have been assessed and are compared with each other, with smaller gas‐phase HgX4 complexes, and with known related noble gas compounds. Most species eliminate F2 exothermically, with energies ranging from only about −60 kJ mol−1 to appreciable −180 kJ mol−1. The lower stability of these species compared to gas‐phase HgF4 is due to relatively high coordination numbers of six in the resulting HgII complexes that stabilize the elimination products. Complexes with AsF6 ligands appear more promising than their SbF6 analogues, due to differential aggregation effects in the HgII and HgIV states. HgF2X2 complexes with X−=OSeF5− or OTeF5− exhibit endothermic fluorine elimination and relatively weak interactions in the HgII products. However, elimination of the peroxidic (OEF5)2 coupling products of these ligands provides an alternative exothermic elimination pathway with energies between −120 and −130 kJ mol−1. While all of the complexes investigated here thus have one exothermic decomposition channel, there is indirect evidence that the reactions should exhibit nonnegligible activation barriers. A number of possible synthetic pathways towards the most interesting condensed‐phase HgIV target complexes are proposed.
Light and electron microscopic analysis of KChIP and Kv4 localization in rat cerebellar granule cells
Authors: Strassle Brian W. , Menegola Milena , Rhodes Kenneth J. , Trimmer James S.
Published: February 2005

Potassium channels are key determinants of neuronal excitability. We recently identified KChIPs as a family of calcium binding proteins that coassociate and colocalize with Kv4 family potassium channels in mammalian brain (An et al. [2000] Nature 403:553). Here, we used light microscopic immunohistochemistry and multilabel immunofluorescence labeling, together with transmission electron microscopic immunohistochemistry, to examine the subcellular distribution of KChIPs and Kv4 channels in adult rat cerebellum. Light microscopic immunohistochemistry was performed on 40‐μm free‐floating sections using a diaminobenzidine labeling procedure. Multilabel immunofluorescence staining was performed on free‐floating sections and on 1‐μm ultrathin cryosections. Electron microscopic immunohistochemistry was performed using an immunoperoxidase pre‐embedding labeling procedure. By light microscopy, immunoperoxidase labeling showed that Kv4.2, Kv4.3, and KChIPs 1, 3, and 4 (but not KChIP2) were expressed at high levels in cerebellar granule cells (GCs). Kv4.2 and KChIP1 were highly expressed in GCs in rostral cerebellum, whereas Kv4.3 was more highly expressed in GCs in caudal cerebellum. Immunofluorescence labeling revealed that KChIP1 and Kv4.2 are concentrated in somata of cerebellar granule cells and in synaptic glomeruli that surround synaptophysin‐positive mossy fiber axon terminals. Electron microscopic analysis revealed that KChIP1 and Kv4.2 immunoreactivity is concentrated along the plasma membrane of cerebellar granule cell somata and dendrites. In synaptic glomeruli, KChIP1 and Kv4.2 immunoreactivity is concentrated along the granule cell dendritic membrane, but is not concentrated at postsynaptic densities. Taken together, these data suggest that A‐type potassium channels containing Kv4.2 and KChIP1, and perhaps also KChIP3 and 4, play a critical role in regulating postsynaptic excitability at the cerebellar mossy‐fiber/granule cell synapse. J. Comp. Neurol. 484:144–155, 2005. © 2005 Wiley‐Liss, Inc.
Neural control mechanisms of the pheromone‐triggered programmed behavior in male silkmoths revealed by double‐labeling of descending interneurons and a motor neuron
Authors: Wada Satoshi , Kanzaki Ryohei
Published: February 2005

Male silkmoths, Bombyx mori, exhibit a characteristic zigzagging behavior consisting of straight‐line walking, zigzagging turns, and looping. The timing for shifting the turning direction is synchronized to the sideways head movements controlled by neck motor neurons (NMNs) including a cervical ventral NMN (cv1‐NMN). It has been suggested that this programmed behavior is instructed by two types of activity patterns descending from the brain and the thoracic ganglion: one is a phasic excitation and the other is a state‐dependent activity similar to the flipflop in electric memory circuits. These activities are shown by certain descending interneurons contained in two subsets of DNs, Group‐I and ‐II DNs. However, it is not yet well understood which DNs are directly related to instructing this behavior. In order to understand neural control mechanisms of this programmed behavior, we investigated the morphological relationship between these DNs and the cv1‐NMN, which is an index of this programmed behavior. We applied a double‐labeling technique combining backfilling of the cv1‐NMN and intracellular staining of single DNs. 3D confocal images revealed overlapping regions between the Group‐I, ‐II DNs and the cv1‐NMN. Group‐IIA and ‐IID, which showed typical flipflop activities, Group‐IIC DNs, which showed phasic excitation, and Group‐IB DNs, which showed long‐lasting inhibition had many overlapping regions on the cv1‐NMNs. Our results indicate that the programmed behavior is instructed by these types of DNs. J. Comp. Neurol. 484:168–182, 2005. © 2005 Wiley‐Liss, Inc.
Retinotectal transmission in the optic tectum of rainbow trout
Authors: Kinoshita Masae , Fukaya Masahiro , Tojima Takuro , Kojima Satoshi , Ando Hironori , Watanabe Masahiko , Urano Akihisa , Ito Etsuro
Published: February 2005

Retinotectal transmission has not yet been well characterized at the cellular level in the optic tectum. To address this issue, we used a teleost, the rainbow trout, and characterized periventricular neurons as postsynaptic cells expected to receive the retinotectal inputs to the optic tectum. The somata of periventricular neurons are localized in the upper zone of the stratum periventriculare (SPV), whereas the lower zone of the SPV comprises the cell body layer of radial glial cells. Ca2+ imaging identified functional ionotropic glutamate receptors in periventricular neurons. We also cloned cDNAs encoding the NR1 subunit of N‐methyl‐D‐aspartic acid (NMDA) receptors and the GluR2 subunit of (±)‐α‐amino‐3‐hydroxy‐5‐methyl‐isoxazole‐4‐propionic acid (AMPA) receptors, and detected their mRNAs in periventricular neurons by in situ hybridization. The presence of the receptor subunit proteins was also confirmed in the dendrites of periventricular neurons by immunoblotting and immunohistochemistry. On the other hand, radial glial cells in the lower zone of the SPV did not respond to glutamate applications, and mRNA and immunoreactivities of ionotropic glutamate receptors were not detected in glial cells. The present findings suggest that glutamatergic transmission at synapses between retinotectal afferents and periventricular neurons is mediated by the functional NMDA and AMPA receptors. J. Comp. Neurol. 484:249–259, 2005. © 2005 Wiley‐Liss, Inc.
Growth hormone expression in the perinatal and postnatal rat lung
Authors: Beyea Jason A. , Olson David M. , Harvey Steve
Published: February 2005

It is now established that the lung is a target site for pituitary growth hormone (GH) action, because pathophysiological states of pituitary GH excess and deficiency are associated with impaired pulmonary function. The onset of lung development and differentiation is, however, before the ontogenic differentiation of pituitary somatotrophs. GH may be involved, nevertheless, in lung development, because it is present in extrapituitary tissues of preimplantation mouse embryos and in the lung buds of embryonic chickens. The possibility that GH may be expressed in the rat lung during fetal and neonatal development, therefore, has been assessed. GH mRNA was detected in the lung, and its 693‐bp sequence was identical to that in the pituitary gland. By in situ hybridization, this transcript was found to be abundantly expressed in the lungs of embryonic day (ED) 17 rats in mesenchymal, mucosal epithelial, and smooth muscle cells. This transcript was expressed in neonates until at least day 14 postnatally and was localized to type I and II epithelial cells and to pulmonary tissue macrophages and alveolar macrophages. GH immunoreactivity paralleled GH mRNA cellular localization throughout the time course studied. This immunoreactivity was specific and was lost after antibody preabsorption. The perinatal and postnatal lung is, therefore, an extrapituitary site of GH gene expression during development. Given that the GH receptor is present in the lung from early development, lung GH may have autocrine and/or paracrine roles in lung growth or differentiation or in pulmonary function. Developmental Dynamics 232:1037–1046, 2005. © 2005 Wiley‐Liss, Inc.
Retinoic acid down‐regulates Tbx1 expression in vivo and in vitro
Authors: Roberts Catherine , Ivins Sarah M. , James Chela T. , Scambler Peter J.
Published: February 2005

Both Tbx1 and retinoic acid (RA) are key players in embryonic pharyngeal development; loss of Tbx1 produces DiGeorge syndrome‐like phenotypes in mouse models as does disruption of retinoic acid homeostasis. We have demonstrated that perturbation of retinoic acid levels in the avian embryo produces altered Tbx1 expression. In vitamin A‐deficient quails, which lack endogenous retinoic acid, Tbx1 expression patterns were disrupted early in development and expression was subsequently lost in all tissues. “Gain‐of‐function” experiments where RA‐soaked beads were grafted into the pharyngeal region produced localized down‐regulation of Tbx1 expression. In these embryos, analysis of Shh and Foxa2, upstream control factors for Tbx1, suggested that the effect of RA was independent of this regulatory pathway. Real‐time polymerase chain reaction analysis of retinoic acid‐treated P19 cells showed a dose‐dependent repression of Tbx1 by retinoic acid. Repression of Tbx1 transcript levels was first evident after 8–12 hr in culture in the presence of retinoic acid, and to achieve the highest levels of repression, de novo protein synthesis was required. Developmental Dynamics 232:928–938, 2005. © 2005 Wiley‐Liss, Inc.
Green Light Luminescence from ZnO/Dodecylamine Mesolamellar Nanocomposites Synthesized by Self‐Assembly
Authors: Wang Yu‐de , Zhang Shuo , Wu Xing‐hui
Published: February 2005

The synthesis, structural characterization and optical properties of a semiconducting zinc oxide based dodecylamine surfactant, mesolamellar zinc oxide/surfactant nanocomposite (Zn‐L) are described. XRD and TEM results showed the formation of a lamellar mesostructure with two layer spacings ca. 28 Å. A red‐shift in the absorption band edge of absorption spectrum and the green light photoluminescence of the resulted nanocomposite were observed at room temperature. The red‐shift of the absorption band edge and the room temperature photoluminescence (RTPL) of the Zn‐L nano‐composite might be induced by the dielectric confinement effect and the interfacial interaction between the ZnO and the surfactant, respectively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
SH‐SS relationships in Ehrlich ascites tumor cells exposed to edathamil
Authors: Dipaolo Joseph A.
Published: February 2005

By means of an amperometric titration method, the acid soluble sulfhydryl, protein sulfhydryl, and disulfide content of Ehrlich ascites tumor cells were determined before and after exposure to edathamil. No statistically significant differences were found between exposed and control groups. The addition of edathamil did not alter oxygen utilization. Changes in the viscosity of cell cytoplasm were determined by observation of the movement of lipoid granules with a phase contrast microscope following high speed centrifugation. The decrease in viscosity observed with edathamil could be prevented by the addition of glutathione simultaneously or 30 minutes later. A shift from intermolecular SS to intramolecular SS during sol‐gel transformation is suggested by the increased viscosity following the addition of glutathione.
Osmoregulation in the amphibian egg the influence of calcium
Authors: Berntsson Karl‐Erik , Haglund Birgit , Løvtrup Søren
Published: February 2005

Determinations of the permeability coefficient for water show that the osmotic behavior of amphibian eggs (ovarian and coelomic eggs from Rana temporaria) cannot be accounted for by this factor alone. Comparison of the cortical stiffness of coelomic eggs with vitelline membrane in iso‐ and hypotonic solutions indicate that a mechanical tension develops under hypotonic conditions, strong enough to resist osmotic swelling.

In Ca++‐free media preservation of this tension is interfered with, but the effect is observed only after exposure for some hours.

Ca++ does not change the diffusion coefficient for water in the egg cytoplasm, nor the permeability coefficient for water through the cell membrane. Neither is the Young's modulus for the vitelline membrane influenced. A slight effect of Ca++ on the cortical stiffness of naked coelomic eggs was observed. In hypotonic Ca++‐free media no resistance to swelling develops in these eggs, and they disintegrate after a rather short time.

To determine the permeability to water the rate of D2O — H2O exchange was measured with the Cartesian diver balance. The stiffness was determined with a cell elastimeter described by Mitchison and Swann, and the osmotic swelling was determined by measuring the egg diameter with an eyepiece screw micrometer.
Effect of ethanol on electrolyte transport and electrogenesis in animal tissues
Authors: Israel‐Jacard Y. , Kalant H.
Published: February 2005

Ethanol 0.087 M (400 mg/100 ml) did not affect the initial loss of K+ from guinea‐pig brain cortex slices at the start of incubation, but significantly inhibited the subsequent reaccumulation of K+. Ethanol 0.098 M (450 mg/100 ml) also significantly inhibited the active reaccumulation of K+ by pre‐cooled rabbit kidney cortex slices.

In vivo experiments with an electric eel indicated that ethanol in concentrations of 100 to 700 mg/100 ml (22 to 152 mM) significantly diminished the frequency of spontaneous low‐voltage electrogenesis.

These findings, together with others in the literature, suggest that ethanol inhibits the active transport of cations by many types of cell, at concentrations relevant to non‐lethal intoxication.